Surface activity of tear fluid in patients with primary Sjögren's syndrome

Rupture of the preocular tear film leads to formation of a dry spot on the cornea with ocular irritation and symptoms of dry eye. One of the factors determining the stability of the tear film is its surface activity. The purpose of this study was to examine the surface activity of tear fluid from patients with Sjögren's syndrome. Tear fluid was sampled from the eyes of 16 patients with primary Sjögren's syndrome. The surface activity of the sample was measured on a Wilhelmy balance. Maximum and minimum surface tension was 72·2 ± 1·7 and 52·9 ± 7·4 mN m^?1, respectively. Corresponding values in a previously studied group of normal subjects were 71·5 ± 1·3 and 46·6 ± 3·8 mN m^–1, respectively. The difference in minimal surface tension was statistically significant (P<0·001). Reduced surface activity may be caused by dysfunction of the Meibomian glands and suggests a mechanism for causing the symptoms of dry eyes.     

Effect of saliva collection methods and oral hygiene on salivary biomarkers

The aim of this study was to evaluate the influence of unstimulated and stimulated saliva collection methods, as well as tooth brushing, on the secretion rate of salivary total protein, nitrite, total antioxidant capacity and alpha-amylase. Saliva of 14 healthy individuals were collected with stimulation using Salivette^®, Parafilm^® and chewing gum and without stimulation from spit with and without fluid accumulation, before and after oral hygiene. Total protein, nitrite, total antioxidant capacity and alpha-amylase concentration (sAA) were evaluated. The collection of saliva stimulated with Parafilm^® and chewing gum increased the salivary flow (1.5?±?0.4 and 3.4?±?0.7?mL/min, respectively) and the secretion rate of salivary total protein (1.0?±?0.2 and 2.3?±?0.5?mg/min, respectively). Also, chewing gum increases the salivary nitrite secretion (213?±?58?nmol/min) and total antioxidant capacity (410?±?47?nmol trolox eq/min). Interestingly, the unstimulated method without saliva accumulation prior to collection resulted in low sAA levels (23,531?±?7979 pixel density). Furthermore, oral hygiene decreased salivary flow (1.3?±?0.5 to 1.0?±?0.4?mL/min), reduced the secretion rate of total protein (1.0?±?0.5 to 0.6?±?0.2?mg/min, p?p?相似文献   

CT based 3D printing is superior to transesophageal echocardiography for pre-procedure planning in left atrial appendage device closure

Accurate assessment of the left atrial appendage (LAA) is important for pre-procedure planning when utilizing device closure for stroke reduction. Sizing is traditionally done with transesophageal echocardiography (TEE) but this is not always precise. Three-dimensional (3D) printing of the LAA may be more accurate. 24 patients underwent Watchman device (WD) implantation (71?±?11 years, 42% female). All had complete 2-dimensional TEE. Fourteen also had cardiac computed tomography (CCT) with 3D printing to produce a latex model of the LAA for pre-procedure planning. Device implantation was unsuccessful in 2 cases (one with and one without a 3D model). The model correlated perfectly with implanted device size (R²?=?1; p?<?0.001), while TEE-predicted size showed inferior correlation (R²?=?0.34; 95% CI 0.23–0.98, p?=?0.03). Fisher’s exact test showed the model better predicted final WD size than TEE (100 vs. 60%, p?=?0.02). Use of the model was associated with reduced procedure time (70?±?20 vs. 107?±?53 min, p?=?0.03), anesthesia time (134?±?31 vs. 182?±?61 min, p?=?0.03), and fluoroscopy time (11?±?4 vs. 20?±?13 min, p?=?0.02). Absence of peri-device leak was also more likely when the model was used (92 vs. 56%, p?=?0.04). There were trends towards reduced trans-septal puncture to catheter removal time (50?±?20 vs. 73?±?36 min, p?=?0.07), number of device deployments (1.3?±?0.5 vs. 2.0?±?1.2, p?=?0.08), and number of devices used (1.3?±?0.5 vs. 1.9?±?0.9, p?=?0.07). Patient specific models of the LAA improve precision in closure device sizing. Use of the printed model allowed rapid and intuitive location of the best landing zone for the device.     

Local effect of lung contusion on lung surfactant composition in multiple trauma patients.

OBJECTIVE: The aim of this study was to investigate the direct influence of lung contusion on pulmonary surfactant in multiple trauma patients. DESIGN: Prospective, nonrandomized study. SETTING: University hospital, trauma intensive care unit. PATIENTS: Eighteen multiple trauma patients with unilateral lung contusions and Injury Severity Scores >19 were studied prospectively. INTERVENTIONS: Bronchoalveolar lavage was performed daily until either day 7 or extubation. Samples from the side of lung contusion (n = 62) and the contralateral, uninjured side (n = 62) were obtained at the same time in 14 patients. Total phospholipids, total phospholipid classes, and surfactant apoprotein A were quantified. Additionally, surfactant function was measured with a pulsating bubble surfactometer in four patients. All data are presented as mean +/- SEM. Statistical analyses were performed using programs of SPSS for Windows 6.1.3 (SPSS Inc., Chicago, IL) (Student's t-test; p < .05). MEASUREMENTS AND MAIN RESULTS: Total phospholipids were significantly increased on the side of lung contusion (contusion side, 40+/-7 microg/mL; contralateral side, 21+/-3 microg/mL; p = .004). The percentage contents of phosphatidylcholine (contusion side, 87.1%+/-1.0%; contralateral side, 84.3%+/-1.0%; p = .04) and sphingomyelin (contusion side, 2.9%+/-0.3%; contralateral side, 1.9%+/-0.2%; p = .004) were significantly higher. In contrast, the percentage content of phosphatidylglycerol was significantly decreased (contusion side, 4.1%+/-0.1%; contralateral side, 6.9%+/-0.6%; p = .001). No alterations were found for the relative contents of phosphatidylethanolamine (contusion side, 2.4%+/-0.2%; contralateral side, 2.2%+/-0.2%; p = .47), phosphatidylinositol (contusion side, 3.5%+/-0.4%; contralateral side, 4.6%+/-0.5%; p = .06), and surfactant apoprotein A (contusion side, 7177+/-1404 ng/mL; contralateral side, 4513+/-787 ng/mL, p = .10). There was no statistical difference for minimal surface tension measured with the pulsating bubble surfactometer after 5 mins of oscillation (contusion side, 29.5+/-2.3 mN/m; contralateral side, 23.7+/-2.1 mN/m; p = .08). CONCLUSIONS: Direct damage of lung parenchyma by lung contusion alters the composition of surfactant. No additional changes in surfactant function were observed that would argue in favor of functional compensation.     

Pilot Study of a Novel 18F-labeled FSHR Probe for Tumor Imaging

Purpose

Follicle-stimulating hormone receptor (FSHR) is overexpressed in primary and metastatic tumor. Molecular imaging of FSHR is beneficial for prognosis and therapy of cancer. FSHβ(33–53) (YTRDLVYKDPARPKIQKTCTF), denoted as FSH1, is a FSHR antagonist. In the present study, maleimide-NOTA conjugate of FSH1 (NOTA-MAL-FSH1) was designed and labeled with [¹⁸F] aluminum fluoride. The resulting tracer, ¹⁸F-Al-NOTA-MAL-FSH1, was preliminarily evaluated in PET imaging of FSHR-positive tumor.

Procedures

NOTA-MAL-FSH1 was synthesized and radiolabeled with Al¹⁸F complex. The tumor-targeting potential and pharmacokinetic profile of the ¹⁸F-labeled compound were evaluated in vitro and in vivo using a PC3 human prostate tumor model.

Results

¹⁸F-Al-NOTA-MAL-FSH1 can be efficiently produced within 30 min with a non-decay-corrected yield of 48.6?±?2.1 % and a radiochemical purity of more than 95 %. The specific activity was at least 30 GBq/μmol. The radiotracer was stable in phosphate-buffered saline and human serum for at least 2 h. The IC₅₀ values of displacement ¹⁸F-Al-NOTA-MAL-FSH1 with FSH1 were 252?±?1.12 nM. The PC3 human prostate tumor xenografts were clearly visible with high contrast after injection of ¹⁸F-Al-NOTA-MAL-FSH1 via microPET. At 30, 60 and 120 min postinjection, the tumor uptakes were 2.98?±?0.29 % injected dose (ID)/g, 2.53?±?0.20 %ID/g and 1.36?±?0.12 %ID/g, respectively. Dynamic PET scanning showed that tumor uptake reached a plateau by about 6 min. Heart peaked earlier and then cleared quickly. Biodistribution studies confirmed that the normal organs except kidney uptakes were all below 1 %ID/g at 1 h p.i. The tumor-to-blood and tumor-to-muscle ratio at 10 min, 0.5, 1, and 2 h after injection were 1.64?±?0.36, 2.97?±?0.40, 9.31?±?1.06, and 13.59?±?2.33 and 7.05?±?1.10, 10.10?±?1.48, 16.17?±?3.29, and 30.88?±?4.67, respectively. The tracer was excreted mainly through the renal system, as evidenced by high levels of radioactivity in the kidneys. FSHR-binding specificity was also demonstrated by reduced tumor uptake of ¹⁸F-Al-NOTA-MAL-FSH1 after coinjection with an excess of unlabeled FSH1 peptide.

Conclusion

NOTA-MAL-FSH1 could be labeled rapidly and efficiently with ¹⁸F using one step method. Favorable preclinical data suggest that ¹⁸F-Al-NOTA-MAL-FSH1 may be a suitable radiotracer for the non-invasive visualization of FSHR positive tumor in vivo.     

Effect of regular physical training on age-associated alteration of body composition in men

Body composition changes with increasing age in men, in that lean body mass decreases whereas fat mass increases. Whether this altered body composition is related to decreasing physical activity or to the known age-associated decrease in growth hormone secretion is uncertain. To address this question, three groups of healthy men (n = 14 in each group), matched for weight, height and body mass index, were investigated using dual-energy X-ray absorptiometry, indirect calorimetry and estimate of daily growth hormone secretion [i.e. plasma insulin-like growth factor I (IGF-I) levels]. Group 1 comprised young untrained subjects aged 31.0 ± 2.1 years (mean ± SEM) taking no regular physical exercise; group 2 consisted of old untrained men aged 68.6 ± 1.2 years; and group 3 consisted of healthy old men aged 67.4 ± 1.2 years undergoing regular physical training for more than 10 years with a training distance of at least 30 km per week. Subjects in group 3 had for the past three years taken part in the ‘Grand Prix of Berne’, a 16.5-km race run at a speed of 4.7 ± 0.6 min km^?1 (most recent race). Fat mass was more than 4 kg higher in old untrained men (P < 0.01, anova ) than in the other groups (young untrained men, 12.0 ± 0.9 kg; old untrained men, 16.1 ± 1.0 kg; old trained men, 11.0 ± 0.8 kg), whereas body fat distribution (i.e. the ratio of upper to lower body fat mass) was similar between the three groups. The lean mass of old untrained men was more than 3.5 kg lower (P < 0.02, anova ) than in the other two groups (young untrained men, 56.4 ± 1.0 kg; old untrained men, 52.4 ± 1.0 kg; old trained men, 56.0 ± 1.0 kg), mostly because of a loss of skeletal muscle mass in the arms and legs (young untrained men, 24.0 ± 0.5 kg; old untrained men 20.8 ± 0.5 kg; old trained men, 23.6 ± 0.7 kg; P < 0.01, anova ). Resting metabolic rate per kilogram lean mass decreased with increasing age independently of physical activity (r = ?0.42, P < 0.005). Fuel metabolism was determined by indirect calorimetry at rest. Protein oxidation was similar in the three groups. Old untrained men had higher (P < 0.001) carbohydrate oxidation (young untrained men, 13.2 ± 1.0 kcal kg^?1 lean mass; old untrained men, 15.2 ± 1.3 kcal kg^?1; old trained men, 7.8 ± 0.8 kcal kg^?1), but lower (P < 0.05, anova ) fat oxidation (young untrained men, 10.1 ± 1.2 kcal kg^?1 lean mass; old untrained men, 6.5 ± 1.0 kcal kg^?1; old trained men, 13.7 ± 1.0 kcal kg^?1) than the other two groups. Mean plasma IGF-I level in old trained men was higher than in old untrained men (P < 0.05), but was still lower than that observed in young untrained men (P < 0.005) (young untrained men, 236 ± 24 ng mL^?1; old untrained men, 119 ± 13 ng mL^?1; old trained men, 166 ±14 ng mL^?1). In summary, regular physical training in older men seems to prevent the changes in body composition and fuel metabolism normally associated with ageing. Whether regular physical training in formerly untrained old subjects would result in similar changes awaits further study.     

Adverse effects of permanent atrial fibrillation on heart failure in patients with preserved left ventricular function and chronic right apical pacing for complete heart block

Background

The impact of atrial fibrillation (AF) on heart failure (HF) was evaluated in patients with preserved left ventricular (LV) function and long-term right ventricular (RV) pacing for complete heart block.

Methods

Clinical, echocardiographic, and laboratory parameters of HF were assessed in 35 patients with established AF who had undergone ablation of the atrioventricular node and pacemaker implantation (Group A) and 31 patients who received dual-chamber pacing for spontaneous complete heart block (Group B).

Results

During a follow-up period of 12.7?±?7.5?years, New York Heart Association (NYHA) functional class increased from 1.3?±?0.5 to 2.1?±?0.6 (p?p?p?p?=?0,21) in Group B. At the end of follow-up, markers of LV function were moderately depressed in Group A compared with those in Group B: NYHA class 2.1?±?0.6 versus 1.6?±?0.7, p?=?0.001; LVEF 53.0?±?8.2 versus 56.9?±?7.0?%, p?p?p?10?%, increasing NYHA class ≥1, and NT-proBNP levels >1,000?pg/ml.

Conclusions

Permanent AF was associated with adverse effects on LV function and symptoms of HF in patients with long-term RV pacing for complete heart block, and appears to play an important role in the development of HF in this specific patient cohort.     

Surfactant

Surfactant, a complex substance containing specific proteins and phospholipids, is essential for gas exchange in the lungs. Research shows that surfactant not only lowers surface tension, but also plays a role in host defense. Surfactant replacement therapy is a cornerstone in the treatment of respiratory distress syndrome in premature infants. New information on endogenous surfactant composition including surfactant apoproteins has led to advances in the surfactant replacement products currently available. Because of the success of surfactant deficiency treatment in neonates, surfactant replacement therapy has been studied in both the pediatric and adult population for the treatment of other respiratory disorders. This article describes the composition, metabolism, and function of endogenous surfactant and other uses of surfactant replacement therapies in neonates.     

Surfactant chemical composition and biophysical activity in acute respiratory distress syndrome.

Acute Respiratory Distress Syndrome (ARDS) is characterized by lung injury and damage to the alveolar type II cells. This study sought to determine if endogenous surfactant is altered in ARDS. Bronchoalveolar lavage was performed in patients at-risk to develop ARDS (AR, n = 20), with ARDS (A, n = 66) and in normal subjects (N, n = 29). The crude surfactant pellet was analyzed for total phospholipids (PL), individual phospholipids, SP-A, SP-B, and minimum surface tension (STmin). PL was decreased in both AR and A (3.48 +/- 0.61 and 2.47 +/- 0.40 mumol/ml, respectively) compared to N (7.99 +/- 0.60 mumol/ml). Phosphatidylcholine was decreased in A (62.64 +/- 2.20% PL) compared to N (76.27 +/- 2.05% PL). Phosphatidylglycerol was 11.58 +/- 1.21% PL in N and was decreased to 6.48 +/- 1.43% PL in A. SP-A was 123.64 +/- 20.66 micrograms/ml in N and was decreased to 49.28 +/- 21.68 micrograms/ml in AR and to 29.88 +/- 8.49 micrograms/ml in A. SP-B was 1.28 +/- 0.33 micrograms/ml in N and was decreased to 0.57 +/- 0.24 micrograms/ml in A. STmin was increased in AR (15.1 +/- 2.53 dyn/cm) and A (29.04 +/- 2.05 dyn/cm) compared to N (7.44 +/- 1.61 dyn/cm). These data demonstrate that the chemical composition and functional activity of surfactant is altered in ARDS. Several of these alterations also occur in AR, suggesting that these abnormalities occur early in the disease process.     

Use of human surfactant low molecular weight apoproteins in the reconstitution of surfactant biologic activity.

Two low molecular weight (LMW) apoproteins were isolated from human pulmonary surfactant. SDS polyacrylamide gel analysis showed one protein (SP 18) to have an apparent molecular weight of 18,000 when unreduced and 9,000 D after reduction. The second protein (SP 9) migrated at approximately 9,000 D in the presence or absence of reducing agents. Both proteins contain a high number of hydrophobic amino acids. The NH2-terminal sequence of SP 18 was determined to be: NH2-phe-pro-ile-pro-leu-pro-tyr-. A cDNA clone isolated from a human adult lung cDNA library contained a long open reading frame encoding at an internal position the human SP 18 amino-terminal sequence. Mixtures of phospholipids (PL) and SP 9 and SP 18 were assessed for their capacity to reduce surface tensions on a pulsating bubble surfactometer. The addition of 1% apoprotein resulted in a reduction of surface tension after 15 s from 42.9 dyn/cm for PL alone to 16.7 and 6.3 dyn/cm for preparations containing SP 9 and SP 18, respectively. In vivo assessment of reconstituted surfactant activity was performed in fetal rabbits. Reconstituted surfactant consisting of PL + 0.5% SP 18 instilled intratracheally at delivery resulted in a marked increase in lung compliance, while the incorporation of 0.5% SP 9 yielded a moderate increase. These data show the ability to produce biologically active surfactant by the addition of isolated LMW apoproteins to defined PL.     

Preserved vasodilator response to adenosine in insulin-dependent diabetes mellitus

Experimental data derived from animal models suggest that the endogenous nucleoside adenosine has important cardioprotective properties. The potent vasodilator effects of adenosine may contribute to this cardioprotection as ischaemia-induced release of endogenous adenosine has been suggested to adjust local blood flow to the metabolic demands of the tissue. Interestingly, the vascular effects of adenosine appeared to be impaired in animal models for diabetes mellitus. This observation may be of importance with respect to the increased cardiovascular mortality in diabetes. Therefore, the authors investigated the in vivo vasodilator effects of adenosine in insulin-dependent diabetic patients. In 12 uncomplicated insulin-dependent male diabetic patients and 12 healthy male age-matched subjects, the brachial artery was cannulated for infusion of adenosine (0.15, 0.5, 1.5, 5, 15 and 50 μg 100^?1 mL min^?1) and for measurement of mean arterial pressure (MAP). Forearm blood flow (FBF) was measured by venous occlusion mercury-in-silastic strain gauge plethysmography. Maximal vasodilatation was assessed by standardized post occlusive reactive hyperaemia (PORH). Baseline forearm blood flow was 2.7 ± 0.4 and 1.8 ± 0.2 0.2 mL 100^?1 mL min^?1 for the diabetic patients and control group respectively. In the diabetic patients, adenosine infusion raised forearm blood flow to 2.4 ± 0.4, 2.6 ± 0.4, 4.4 ± 0.7, 6.3 ± 1.0, 9.8 ± 1.5 and 14.2 ± 2.1 mL 100^?1 mL min^?1 for the respective dosages. In the control group these values were 1.7 ± 0.21, 1.9 ± 0.3, 3.2 ± 0.8, 6.0 ± 1.2, 10.9 ± 2.1 and 17.1 ± 3.4 mL 100^?1 mL min^?1 respectively (P > 0.1 for between group comparison). Forearm blood flow at the contralateral side was not significantly affected by the placebo and adenosine infusions. Similar results were obtained when results were expressed as changes in forearm vascular resistance or forearm blood flow ratio (FBF infused arm/FBF control arm). Maximal vasodilatation did not differ between the two groups. The authors conclude that the forearm vasodilator response to adenosine is preserved in uncomplicated insulin-dependent diabetic patients. This observation argues against a primary role of a reduced adenosine responsiveness in the cardiovascular sequelae of diabetes.     

In vitro and in vivo intrapulmonary distribution of fluorescently labeled surfactant

OBJECTIVE: To determine the distribution of endotracheally administered surfactant at the alveolar level in an animal model of acute respiratory distress syndrome. DESIGN: Prospective, randomized animal study. SETTING: Research laboratory of a university hospital. SUBJECTS: Seventy-one male Sprague-Dawley rats, weighing 330-370 g. INTERVENTIONS: To measure surfactant distribution in vitro, a glass trough mimicking dichotomic lung anatomy was used to determine the spreading properties of bovine lung surfactant extract supplemented with fluorescent Bodipy-labeled surfactant protein B. To measure surfactant distribution in vivo, rats were anesthetized, and lipopolysaccharide was aerosolized (12 mg/kg body weight) to induce lung injury resembling acute respiratory distress syndrome; in control rats, buffered saline was aerosolized. Twenty-four hours later rats were anesthetized, tracheotomized, and mechanically ventilated (peak airway pressure = 20 mbar; positive end-expiratory pressure = 6 mbar; inspiration time = expiration time = 0.6 sec; Fio2 = 50%). Surfactant (bovine lung surfactant extract, supplemented with fluorescent Bodipy-labeled surfactant protein B; 50 mg/kg body weight) was applied as a bolus; in control rats, saline was administered as a bolus. Rats were ventilated for 5, 15, 30, or 60 mins (n = 8 or 9 for each group). Then, lungs were excised and sliced. Lung slices, divided into aerated (open), underinflated (dystelectatic), or collapsed (atelectatic) alveolar areas, were examined by both light and fluorescence microscopy. RESULTS: In vitro experiments revealed that surfactant spread independent of glass trough geometry and lowered the surface tension to equilibrium values (25 mN/m) within a few seconds. In vivo experiments showed that administered surfactant distributed preferentially into underinflated and aerated alveolar areas. Furthermore, surfactant distribution was not affected by length of mechanical ventilation. CONCLUSIONS: When conventional mechanical ventilation was used in lipopolysaccharide-induced lung injury, surfactant preferentially distributed into underinflated and aerated alveolar areas. Because surfactant rarely reached collapsed alveolar areas, methods aiding in alveolar recruitment (e.g., open lung concept or body positioning) should precede surfactant administration.     

Daily variation in circulating cytokines and acute-phase proteins correlates with clinical and laboratory indices in community-acquired pneumonia

Our objective was to investigate the initial levels of circulating proinflammatory cytokines, such as interleukin 1β (IL-1β), interleukin 6 (IL-6), and tumour necrosis factor alpha (TNF-α), of certain acute-phase proteins, such as C-reactive protein (CRP), fibrinogen (FBN) and albumin, and of the glycoprotein fibronectin at presentation and their daily variation during the clinical course of community-acquired pneumonia (CAP) in relation to clinical and laboratory indices of infection. Thirty otherwise healthy hospitalized patients aged 48 ± 3 years (mean ± SEM) and with bacteriologically confirmed CAP were studied prospectively. IL-1β and IL-6 were found to be 15-fold higher on admission (122 ± 9 pg mL^?1 and 60 ± 4 pg mL^?1 respectively), whereas TNF-α was three-fold higher (102 ± 5 pg mL^?1) than those of controls, all of them showing a decline towards normal. Initial CRP levels were increased 90-fold (416 ± 1 mg L^?1), whereas fibronectin levels were reduced (242 ± 9 mg dL^?1). The presence of parapneumonic effusion was associated with a higher TNF-α serum level (127 ± 7 vs. 86 ± 4 pg mL^?1, P = 0.0002), a more rapid daily decline in TNF-α (–7.2 ± 0.7 vs. ?3.8 ± 0.5 pg mL^?1 day^?1, P = 0.0005), a slower rate of decline in CRP (?42.8 ± 3.0 vs. ?54.6 ± 3.0 mg L^?1 day^?1, P = 0.02) and a slower rate of increase in FBN (5.9 ± 1.0 vs. 11.7 ± 1.0 mg dL^?1 day^?1), P = 0.001]. Furthermore, daily progression of serum levels of cytokines and acute-phase proteins correlated strongly with pyrexia, erythrocyte sedimentation rate (ESR), neutrophil count, alveolar–arterial oxygen difference and radiographic resolution, clinically manifested by improvement in the patients' condition.     

Acute hyperinsulinaemia decreases cholesterol synthesis less in subjects with non-insulin-dependent diabetes mellitus than in non-diabetic subjects

To investigate the effect of insulin on cholesterol synthesis in vivo we measured plasma mevalonic acid (MVA) concentrations using gas chromatography–mass spectrometry in six non-obese patients with non-insulin-dependent diabetes mellitus (NIDDM) [four men, two women; age 57.5±2.2 years (mean±SEM); glycated haemoglobin (HbA1) 8.5±0.5%; total cholesterol (TC) 5.7±0.5 mmol L^?1, triglyceride (TG) 3.8±0.9 mmol L^?1] and six non-diabetic, sex- and age-matched control subjects (age 55.7±2.8 years; HbA1 6.5±0.1%; TC 5.4±0.3 mmol L^?1, TG 1.2±0.1 mmol L^?1). Subjects were studied twice: during 13-h hyperinsulinaemic (1 mu kg^?1 min^?1), euglycaemic (5 mmol L^?1) clamp and during a saline infusion. Baseline MVA concentration was significantly higher in diabetic patients than in control subjects (9.8±0.7 ng mL^?1 vs. 5.6±0.9 ng mL^?1P=0.004). At the end of each study, MVA concentration, expressed as a percentage of baseline, was significantly lower during the hyperinsulinaemic, euglycaemic clamp than during the saline study in both the diabetic (54.4±5.3% vs. 69.6±6.3%, P=0.036) and control subjects (30.5±3.4% vs. 61.7±6.0%, P=0.01). However, the decrease in MVA during the hyperinsulinaemic clamp study was more marked in the control subjects than in the diabetic subjects (P=0.03). A significant positive correlation was found between percentage decrease of MVA and non-esterified fatty acids following the insulin clamp in NIDDM (r=0.83, P=0.04). We conclude that acute hyperinsulinaemia decreases cholesterol synthesis less in subjects with NIDDM than in non-diabetic subjects and that this phenomenon, together with increased basal cholesterol synthesis in NIDDM, may in part be due to insulin resistance.     

Influence of methoctramine on the acetylcholine-isoprenaline functional antagonism in the guinea pig isolated trachea

Summary— It has been suggested that activation of muscarinic M₂ receptors is one of the components of the functional antagonism between muscarinic and β-adrenoceptor agonists in canine and guinea pig tracheal smooth muscle. The aim of the present study was to determine in the guinea pig trachea the importance of this component according to the magnitude of the acetylcholine-induced contraction. Cumulative concentration-response curves for isoprenaline were obtained in the absence or presence of the muscarinic M₂ receptor antagonist methoctramine (3 × 10^?7 M) in tracheal rings under basal tension or precontracted by acetylcholine 2 × 10^?7, 3 × 10^?6 and 10^?4 M, giving contractions of 25, 50 or 75%, respectively, of the maximal tension induced by acetylcholine 3 × 10^?3 M. In the absence of methoctramine, acetylcholine induced a concentration-dependent shift of the concentration-response curves of isoprenaline (-log EC₅₀ of isoprenaline are 8.09 ± 0.07, 7.85 ± 0.08, 7.38 ± 0.12 and 6.49 ± 0.12, n = 6 for basal tension and for acetylcholine concentrations of 2 × 10^?7, 3 × 10^?6 and 10^?4 M, respectively). In the presence of methoctramine, the basal -log EC₅₀ of isoprenaline was unmodified, whereas the acetylcholine-induced shifts of concentration-response curves of isoprenaline were abolished for low levels of contraction (25%) and significantly reduced to 50 and 75% levels of contraction. Under similar conditions, acetylcholine-induced shifts of concentration-response curves of isoprenaline were unmodified by the muscarinic M₁ receptor antagonist pirenzepine (10^?7 M). These results suggest that the inhibitory effect of M₂ receptors on β-adrenoceptor agonists effects is important for low contraction levels induced by acetylcholine, and that this effect becomes less important for higher concentrations of acetylcholine.     

TEG® and RapidTEG® are unreliable for detecting warfarin-coagulopathy: a prospective cohort study

Background

Thromboelastography^® (TEG) utilizes kaolin, an intrinsic pathway activator, to assess clotting function. Recent published studies suggest that TEG results are commonly normal in patients receiving warfarin, despite an increased International Normalized Ratio (INR). Because RapidTEG? includes tissue factor, an extrinsic pathway activator, as well as kaolin, we hypothesized that RapidTEG would be more sensitive in detecting a warfarin-effect.

Methods

Included in this prospective study were 22 consecutive patients undergoing elective cardioversion and receiving warfarin. Prior to cardioversion, blood was collected to assess INR, Prothrombin Time, TEG, and RapidTEG.

Results

INR Results: 2.8?±?0.5 (1.6 to 4.2). Prothrombin Time Results: 19.1?±?2.2 (13.9. to 24.3). TEG Results (Reference Range): R-Time: 8.3?±?2.7 (2–8); K-Time: 2.1?±?1.4 (1–3); Angle: 62.5?±?10.3 (55–78); MA: 63.2?±?10.3 (51–69); G: 9.4?±?3.5 (4.6-10.9); R-Time within normal range: 10 (45.5%) with INR 2.9?±?0.3; Correlation coefficients for INR and each of the 5 TEG variables were insignificant (P?>?0.05). RapidTEG Results (Reference Range): ACT: 132?±?58 (86–118); K-Time: 1.2?±?0.5 (1–2); Angle: 75.4?±?5.2 (64–80); MA: 63.4?±?5.1 (52–71); G: 8.9?±?2.0 (5.0-11.6); ACT within normal range: 9 (40.9%) with INR 2.7?±?0.5; Correlation coefficients for INR and each of the 5 RapidTEG variables were insignificant (P?>?0.05).

Conclusions

TEG, using kaolin activation, and RapidTEG, with kaolin and tissue factor activation, were normal in a substantial percent of warfarin patients, despite an increased INR. The false-negative rate for detecting warfarin coagulopathy with either test is unacceptable. The lack of correlation between INR and all TEG and RapidTEG components further indicates that these methodologies are insensitive to warfarin effects. Findings suggest that intrinsic pathway activation may mitigate detection of an extrinsic pathway coagulopathy.     

A Fractally Coated, 1.3 mm2 High Impedance Pacing Electrode

Minimizing the geometric surface area of pacing electrodes increases impedance and reduces the current drain during stimulation, provided that voltage (pulse-width) thresholds remain unchanged. This may be feasible by coating the electrode surface to increase the capacity of the electrode tissue interface and to diminish polarization. Ten unipolar, tined leads with a surface area of 1.3 mm² and a “fractal” coating of Iridium (Biotronik SD-V137) were implanted in the ventricle, and electrogram amplitude (unfiltered), slew-rate, pacing threshold (0.5 ms), and impedance (2.5 V; 0.5 ms) were measured by the 5311 PSA (Medtronic). On days 0, 2, 5, 10, 28, 90, 180, 360 postimplant, sensing threshold (up to 7.0 mV, measuring range 1–14 mV on day 360 only) and the strength duration curve (0.5–4.0 V; 0.03–1.5 ms; steps: 0.5 V; 0.01 ms, respectively) were determined, the minimum charge delivered per pulse (charge threshold), and the impedance were taken from pacemaker telemetry (Intermedics 294–03). Data were compared with those of an earlier series of 20 unipolar, tined TIR-leads (Biotronik) with a surface area of 10 mm² and a “fractal” coating of titanium nitride. With the model SD-V137 versus TIR, intraoperative electrogram amplitudes were 15.1 ± 6.1 versus 14.4 ± 3.9 mV(NS), slew rates 3.45 ± 1.57 versus 1.94 ± 1.06 V/s (P < 0. 05), pacing thresholds 0.16 ± 0.05 versus 0.52 ± 0.15 V (P < 0.01) and impedance measurements 1,136 ±175 versus 441 ± 73 Ω (P < 0.0001), respectively. During follow-up, sensing thresholds were the same with both leads. Differences in pulse width thresholds lost its significance on day 28 but resumed on day 360 (SD-V137: 0.08 ± 0.04 ms; TIR: 0.16 ± 0.06 ms at 2.5 V; P < 0.01). With an electrode surface of 1.3 mm², charge per pulse and impedance consistently differed from control, beingO.15 ± 0.15 versus 0. 66 ± 0. 20 μC (P < 0.001) and 1,344 ± 376 versus 538 ± 79 Ω, respectively, one year after implantation (P < 0.0001). In summary, “fractally” coated small surface electrodes do not compromise sensing; by more than doubling impedance against controls they offer pacing thresholds (mainly in terms of charge) that are significantly lower than with the reference electrode.     

Arterial antithrombotic and bleeding time effects of apixaban,a direct factor Xa inhibitor,in combination with antiplatelet therapy in rabbits

Summary. Background: Optimal treatment of arterial thrombosis may include a combination of antiplatelet and anticoagulant drugs. We evaluated apixaban, a direct and highly selective factor Xa inhibitor, in combination with clinically relevant doses of aspirin and/or clopidogrel for prevention of arterial thrombosis in rabbits. Methods: Studies were conducted in rabbit models of electrically induced carotid artery thrombosis and cuticle bleeding time (BT). Apixaban 0.04 and 0.3 mg kg^?1 h^?1 or aspirin 1 mg kg^?1 h^?1 was infused intravenous (i.v.) continuously from 1 h before artery injury or cuticle bleed until the end of the experiment. Clopidogrel at 3 mg kg^?1 was dosed orally once daily for three days, with the last dose given 2 h before injury. Results: Control thrombus weight and BT averaged 8.6 ± 0.9 mg and 181 ± 12 s, respectively (n = 6 per group). Effective doses of apixaban that reduced thrombus weight by 20 and 50% (ED₂₀ and ED₅₀) were 0.04 and 0.3 mg kg^?1 h^?1 i.v., respectively. Addition of aspirin to apixaban ED₂₀ and ED₅₀ significantly reduced the thrombus weight from 7.4 ± 0.5 to 5.3 ± 0.3 and 3.6 ± 0.3 mg, respectively, with no significant increases in BT (190 ± 7 s vs.181 ± 9 and 225 ± 11 s, respectively). Addition of aspirin and apixaban (ED₂₀ dose) to clopidogrel produced a further significant reduction in thrombus weight from 5.3 ± 0.3 to 0.7 ± 0.1 mg. This combination of clopidogrel and aspirin with apixaban (ED₂₀ dose) produced a significant but moderate BT increase of 2.1 times control. Conclusions: The combination of apixaban and aspirin or apixaban, aspirin and clopidogrel can reduce formation of occlusive arterial thrombosis without excessive increases in BT in rabbits.     

The Utility of [<Superscript>18</Superscript>F]DASA-23 for Molecular Imaging of Prostate Cancer with Positron Emission Tomography

Purpose

There is a strong, unmet need for superior positron emission tomography (PET) imaging agents that are able to measure biochemical processes specific to prostate cancer. Pyruvate kinase M2 (PKM2) catalyzes the concluding step in glycolysis and is a key regulator of tumor growth and metabolism. Elevation of PKM2 expression was detected in Gleason 8–10 tumors compared to Gleason 6–7 carcinomas, indicating that PKM2 may potentially be a marker of aggressive prostate cancer. We have recently reported the development of a PKM2-specific radiopharmaceutical [¹⁸F]DASA-23 and herein describe its evaluation in cell culture and preclinical models of prostate cancer.

Procedure

The cellular uptake of [¹⁸F]DASA-23 was evaluated in a panel of prostate cancer cell lines and compared to that of [¹⁸F]FDG. The specificity of [¹⁸F]DASA-23 to measure PKM2 levels in cell culture was additionally confirmed through the use of PKM2-specific siRNA. PET imaging studies were then completed utilizing subcutaneous prostate cancer xenografts using either PC3 or DU145 cells in mice.

Results

[¹⁸F]DASA-23 uptake values over 60-min incubation period in PC3, LnCAP, and DU145 respectively were 23.4?±?4.5, 18.0?±?2.1, and 53.1?±?4.6 % tracer/mg protein. Transient reduction in PKM2 protein expression with siRNA resulted in a 50.1 % reduction in radiotracer uptake in DU145 cells. Small animal PET imaging revealed 0.86?±?0.13 and 1.6?±?0.2 % ID/g at 30 min post injection of radioactivity in DU145 and PC3 subcutaneous tumor bearing mice respectively.

Conclusion

Herein, we evaluated a F-18-labeled PKM2-specific radiotracer, [¹⁸F]DASA-23, for the molecular imaging of prostate cancer with PET. [¹⁸F]DASA-23 revealed rapid and extensive uptake levels in cellular uptake studies of prostate cancer cells; however, there was only modest tumor uptake when evaluated in mouse subcutaneous tumor models.

     

Pulmonary surfactant in patients with Pneumocystis pneumonia and acquired immunodeficiency syndrome

OBJECTIVE: Pneumocystis pneumonia (PCP) is a severe infection of the immunocompromised host, resulting in diffuse alveolar damage and life-threatening respiratory failure. We analyzed pulmonary surfactant composition and function in bronchoalveolar lavage fluid (BALF) from ventilated and spontaneously breathing HIV-positive patients with PCP. DESIGN: Prospective clinical trial. SETTING: University hospital intensive care unit. PATIENTS: Thirty-four spontaneously breathing (SB-PCP) and 20 ventilated HIV-positive patients with PCP (V-PCP), ten patients with acute respiratory distress syndrome (ARDS), 11 spontaneously breathing patients with bacterial pneumonia (PNEU), and 22 healthy volunteers. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Total phospholipid in BALF did not differ between any category vs. controls, whereas total protein increased approximately 14-fold in V-PCP and five-fold in SB-PCP compared with controls (p < .001). The relative content of large surfactant aggregates (LA) was reduced in SB-PCP and V-PCP compared with controls (p < .05). The phospholipid and fatty acid profiles showed a significant reduction in the relative content of phosphatidylcholine (PC), phosphatidylglycerol, and palmitic acid in PC in all patient categories compared with controls, with more in V-PCP (p < .001) compared with SB-PCP (p < .05). The neutral lipid-to-phospholipid ratio in LA was three-fold elevated in V-PCP (p < .01 compared with control) but not in SB-PCP. Analysis of neutral lipid classes showed a significant increase in the relative content of triglycerides and a reduction in free fatty acids in V-PCP compared with controls. BALF surfactant protein (SP)-A and SP-D significantly increased in V-PCP and SB-PCP, but not in ARDS and PNEU, compared with controls (p < .05). SP-B and SP-C content in LA remained unchanged in PCP compared with controls but decreased significantly in ARDS and PNEU. The minimum surface tension of LA was impaired (p < .001) in V-PCP more than in SB-PCP and was strongly correlated with the reduction in palmitic acid levels in PC LA (r = -.81). Reductions in phosphatidylglycerol strongly correlated with decreased Pao2/Fio2 values (r = .72). CONCLUSIONS: We conclude that severe alterations in surfactant function and composition occur in patients with PCP and are even more pronounced in ventilated patients than in nonventilated patients. Surfactant lipid changes in PCP, but not surfactant protein profiles, closely resemble those found in ARDS.