Human placental nitric oxide synthase activity is not altered in diabetes.

Endothelial nitric oxide synthase (NOS) protein and mRNA have been identified and calcium-dependent NOS activity has been measured in human placentae during normal pregnancy. Recently, mRNA and protein for the inducible isoform of NOS have been detected in placentae of women with gestational diabetes. The aim of this study was to determine whether calcium-independent (ciNOS) and/or total (tNOS) NOS activities were increased in placentae obtained after vaginal delivery or Caesarean section from women assigned to the following groups according to standard obstetric criteria: gestational diabetes, diabetes before pregnancy and non-diabetic controls. tNOS and ciNOS were assessed by measuring the conversion of [3H]L-arginine to [3H]L-citrulline in the three groups. Michaelis-Menten constants (Km) and maximum velocities of reaction (Vmax) were calculated using Lineweaver-Burk analysis for tNOS. There were no significant differences in either ciNOS, Vmax or Km values between any of the three groups (normal, ciNOS 12.7+/-1.6%, Vmax 16.6+/-3.3 pmol.min-1.mg-1 protein, Km 15.30+/-2.6 micromol/l; gestational diabetes, ciNOS 15.4+/-1.4%, Vmax 14.8+/-5.2 pmol.min-1. mg-1 protein, Km 10.5+/-1.7 micromol/l; diabetes before pregnancy, ciNOS 13.4+/-1.1%, Vmax 14.9+/-3.4 pmol.min-1.mg-1 protein, Km 17. 7+/-2.2 micromol/l). The presence of macrosomia did not affect tNOS activity in those with diabetes before pregnancy, and glycosylated haemoglobin levels measured between weeks 27 and 39 were not correlated with ciNOS activity. The results from the present study do not provide evidence for increased placental tNOS or ciNOS activities in pregnancies complicated by gestational diabetes or diabetes present before pregnancy.     

Monocrotaline pyrrole-induced cardiopulmonary toxicity is not altered by metergoline or ketanserin

Monocrotaline pyrrole (MCTP) causes endothelial cell damage, pulmonary hypertension and right ventricular hypertrophy in rats by an undetermined mechanism. A role for 5-hydroxytryptamine (5-HT) in the cardiopulmonary response to MCTP has been suggested. To investigate the role of 5-HT, the effects of two 5-HT receptor antagonists were examined in MCTP-treated rats. Cotreatment with metergoline, an antagonist which binds to both 5-HT1 and 5-HT2 receptors, did not alter MCTP-induced elevation of lung weight or right ventricular hypertrophy. 5-HT-induced vascular smooth muscle contractions are mediated by 5-HT2 receptors; therefore, MCTP-treated rats were cotreated with ketanserin (KET), a specific 5-HT2 receptor antagonist. At a dosing regimen of KET that inhibited the 5-HT-induced platelet shape change in platelet-rich plasma and the 5-HT-induced increase in perfusion pressure in isolated lungs, KET did not affect the elevation in lung weight or the increased accumulation of 125I-albumin in the lung tissue of MCTP-treated rats. Moreover, MCTP-induced right ventricular hypertrophy was not attenuated by KET. These results indicate that cotreatment with either of these two 5-HT receptor antagonists does not alter the lung injury or right ventricular hypertrophic response to MCTP and suggest that 5-HT is not necessary for MCTP-induced toxicity.     

The steady-state disposition of indinavir is not altered by the concomitant administration of clarithromycin

STUDY OBJECTIVES: To evaluate the safety and potential pharmacokinetic interaction between indinavir and clarithromycin. STUDY METHODS: In a randomized, three-period, crossover fashion, 12 healthy adults received the following for 1 week: 800 mg oral indinavir sulfate every 8 hours with placebo, 500 mg oral clarithromycin every 12 hours with placebo, and indinavir sulfate with clarithromycin. Plasma indinavir, clarithromycin, and 14-hydroxyclarithromycin concentrations were determined after the last dose in each treatment period. RESULTS: Administration of indinavir sulfate with clarithromycin caused a statistically significant increase in four pharmacokinetic parameters: a 58% increase in plasma indinavir concentrations at 8 hours (P = .029), a 47% increase in values for clarithromycin area under the plasma concentration versus time curve from time zero to the last measured concentration [AUC(0-12h); P = .0002], and 49% and 48% decreases in 14-hydroxyclarithromycin AUC(0-12h) and maximum plasma concentration (Cmax) values, respectively (P = .0001 and P = .0001). These effects are not considered to be clinically significant in view of the insignificant effects on the values for indinavir area under the plasma concentration versus time curve from time zero to the last measured concentration [AUC(0-8h)] and Cmax, as well as the safety profile of clarithromycin. CONCLUSIONS: The combination of indinavir sulfate and clarithromycin is generally well tolerated and can be coadministered without dose adjustment.     

Serum lysophosphatidylcholine level is not altered in coronary artery disease

ObjectivesLysophosphatidylcholine (LPC) is a promising biomarker for atherosclerosis and phospholipase activity. Serum LPC level in patients with coronary artery disease (CAD) was compared with controls.Design and methodsEighty five CAD patients and 105 controls were enrolled. For sera from both groups of patients, twelve molecular species of LPC and lipid profile were measured. Associations with CAD were investigated and factors affecting serum LPC level were analyzed.ResultsIndividual LPC species, inter-species ratio, and the ratio to serum lipids were not associated with CAD. Diabetes was associated with decreased level of LPC 16:1. The ratios of LPC 16:0 to LPC 18:1, LPC 16:0 to 18:2, LPC 18:0 to LPC 18:1, and LPC 18:0 to LPC 18:2 were significantly affected by sex. Current smokers had lower LPC 18:0 to LPC 18:1 ratio.ConclusionSerum LPC level is not altered in patients with CAD proven by coronary angiography.     

Color vision but not visual attention is altered in migraine

OBJECTIVE: To examine visual search performance in migraine and headache-free control groups and to determine whether reports of selective color vision deficits in migraine occur preattentively. BACKGROUND: Visual search is a classic technique to measure certain components of visual attention. The technique can be manipulated to measure both preattentive (automatic) and attentive processes. Here, visual search for colored targets was employed to extend earlier reports that the detection or discrimination of colors selective for the short-wavelength sensitive cone photoreceptors in the retina (S or "blue" cones) is impaired in migraine. METHOD: Visual search performance for small and large color differences was measured in 34 migraine and 34 control participants. Small and large color differences were included to assess attentive and preattentive processing, respectively. In separate conditions, colored stimuli were chosen that would be detected selectively by either the S-, or by the long- (L or "red") and middle (M or "green")-wavelength sensitive cone photoreceptors. RESULTS: The results showed no preattentive differences between the migraine and control groups. For active, or attentive, search, differences between the migraine and control groups occurred for colors detected by the S-cones only, there were no differences for colors detected by the L- and M-cones. The migraine group responded significantly more slowly than the control group for the S-cone colors. CONCLUSIONS: The pattern of results indicates that there are no overall differences in search performance between migraine and control groups. The differences found for the S-cone colors are attributed to impaired discrimination of these colors in migraine and not to differences in attention.     

Ratio of creatine kinase 2 mass concentration to total creatine kinase activity not altered by heavy physical exercise.

Serum creatine kinase isoenzyme 2 concentrations (CK 2 mass) were measured in marathon runners during training and 1 and 2 days after a race and compared with values from 36 acute myocardial infarction (AMI) patients whose total CK and (or) CK 2 activities were similar to those of runners in the basal state. During training, runners had CK and CK 2 activities 53% and 43% above reference values, respectively, and 36% had CK 2 activity > 5% of total CK. Nine runners (26%) showed CK 2 mass values > 6 micrograms/L but < or = 10 micrograms/L; 35 of the AMI subjects, despite having CK activities similar to those of runners, had values > 10 micrograms/L. The ratio of CK 2 mass to total CK activity was significantly (P < 0.0002) different between sexes for runners. At 1 and 2 days after racing, 100% of CK and CK 2 activities and 71% and 57% of the percentages of CK 2 activity, respectively, were abnormally high; 57% and 43% of CK 2 mass values were > 10 micrograms/L, being comparable with those observed for the AMI group. Basal CK 2 mass values of the runners appeared only slightly higher than that for sedentary subjects, but after exercise half the subjects presented increased values similar to those observed for AMI subjects. The ratio of CK 2 mass to total CK activity appeared unaltered by exercise in all but one of the samples assayed, indicating its utility in evaluating CK 2 mass increases originating in skeletal muscle.     

The effect of ambient temperature extremes on tympanic and oral temperatures.

Exposure to ambient temperature extremes immediately preceding emergency department triage may affect tympanic membrane temperatures taken with infrared emission detection thermometers. In a prospective, unblinded study, 20 healthy subjects, on 2 separate days, underwent 15-minute exposures to hot (43.5 degrees C) and cold (-5 degrees C) temperature extremes in an environmental control room (ECR). Tympanic and oral temperatures were taken at baseline and at 2-minute intervals for 20 minutes after exiting the ECR. Rectal temperatures remained stable during the exposures. Oral temperatures rose significantly after hot exposure (P less than .05; max 0.4 degrees C) and briefly decreased after cold exposure (max 0.5 degrees C). Tympanic temperatures were elevated for 20 minutes after hot exposure (max 0.8 degrees C) and decreased briefly only in male subjects after cold exposure (max 0.7 degrees C). Individuals demonstrated wide variability in their temperature responses. Tympanic and oral temperatures taken within the first 20 minutes after exposure to outdoor temperature extremes may fail to accurately reflect the patient's true temperature.     

Cytochrome P-450 activity is differentially altered in severely injured patients

OBJECTIVE: To assess whether changes in cytochrome P-450 (CYP) activity of specific CYP enzymes occur in severely injured patients and to assess changes in CYP activity during recovery. DESIGN: Prospective clinical study. SETTING: University-affiliated, level I trauma center and trauma critical care unit. PATIENTS: Twenty-three multiply injured patients admitted to a trauma critical care unit were compared with healthy volunteers. INTERVENTIONS: CYP metabolizing activity was assessed using the probe drugs mephenytoin (CYP-2C19), chlorzoxazone (CYP-2E1), dapsone (multiple CYP enzymes), and flurbiprofen (CYP-2C9). MEASUREMENTS AND MAIN RESULTS: Mephenytoin metabolism was profoundly suppressed after injury and increased during postinjury recovery, whereas chlorzoxazone metabolism was suppressed to a lesser degree. Measures of dapsone and flurbiprofen metabolism were elevated throughout the study. Chlorzoxazone and mephenytoin metabolism correlated with the multiple organ dysfunction score and with the multiple organ failure score. CONCLUSIONS: CYP isoform activity is differentially altered by shock and trauma in injured patients. The metabolic activity of selected CYP isoforms may have potential for evaluating acute hepatic dysfunction in critically ill trauma patients.     

Soleus H-reflex recruitment is not altered in persons with chronic spinal cord injury

OBJECTIVE: To determine whether spasticity in persons with spinal cord injury (SCI) is associated with elevated monosynaptic reflex excitability. DESIGN: One-way experimental. SETTING: Research laboratory. PARTICIPANTS: Convenience sample of 9 subjects (8 men, 1 woman) with chronic and complete SCI and 20 persons (14 men, 6 women) with no neurologic impairment. Subjects with SCI exhibited lower-extremity spasticity as indicated by velocity-dependent increased resistance to passive muscle stretch, abnormally brisk deep tendon reflexes, involuntary lower-extremity flexion and/or extension spasms, and clonus. INTERVENTION: Soleus H-reflex recruitment curves were elicited in all subjects. MAIN OUTCOME MEASURES: Soleus H-reflex threshold (HTH), gain (HGN), and amplitude (HPP). RESULTS: There was no difference between subjects with and without SCI in HTH, HGN, or HPP. CONCLUSIONS: Spasticity in people with chronic and complete SCI was not associated with increased excitability of the connections between Ia afferent projections and motoneurons. Factors extrinsic to these connections may have a role in spasticity caused by SCI.     

Morphine-induced depression of spinal excitation is not altered following acute disruption of GABAA or GABAB receptor activity

Loss of spinal inhibitory mechanisms is thought to contribute to the pathophysiology of abnormal pain states, including neuropathic pain. By using an evoked spinal field potential technique, the hypothesis was tested here that decreased spinal GABAergic control underlies poor response to morphine (MOR) that often accompanies neuropathic pain. Therefore, field potentials evoked by electrical peripheral nerve stimulation during spinal superfusion with MOR were recorded in rats rendered neuropathic by a spinal nerve ligation (SNL) procedure, and compared to responses recorded in naı¨ve rats. MOR effects on evoked field potentials were then assessed in rats in which spinal GABAergic inhibition had been acutely reduced by treatment with GABA_A and GABA_B receptor-antagonists.In naı¨ve animals, field potentials evoked by peripheral C fibre-input were significantly decreased by spinal superfusion with 1 μM MOR, whereas those elicited by Aδ fibre input were reduced to a lesser extent also (10 μM, p < 0.05). Nine to eleven days after surgery, animals subjected to SNL exhibited significantly reduced thresholds to plantar stimulation with von Frey filaments. In electrophysiological experiments, a small but significant decrease of the IC₅₀ value (2.17 ± 0.38 μM) for MOR was found in rats subjected to SNL, relative to naı¨ve rats (8.65 ± 0.76 μM). In contrast, MOR failed to reduce field potentials evoked by peripheral Aδ fibre-activation at any dose tested (up to 1 mM).C fibre- and Aδ fibre-evoked spinal field potentials disinhibited by prior application of the GABA_B or GABA_A receptor-antagonists CGP35348 (1 mM) or bicuculline (50 μM), respectively, were both significantly reduced by MOR, with IC₅₀ values not significantly differing from those in naı¨ve animals. Two-way analysis of variance revealed no interaction of MOR with either CGP354348 (p = 0.42) or BIC (p = 0.14).Evidence is presented here that injury to the primary afferent system results in significant changes in the ability of spinal MOR to depress field potentials evoked by peripheral input. However, the present findings do not support a pathogenic role for decreased GABAergic inhibition in such changes.     

Phosphorylation of beta-D-ribosylbenzimidazoles is not required for activity against human cytomegalovirus.

We have previously reported that 2,5,6-trichloro-1-(beta-D-ribofuranosyl)benzimidazole (TCRB) and its 2-bromo analog (2-bromo-5,6-dichloro-1-(beta-D-ribofuranosy)benzimidazole [BDCRB]) are potent and selective inhibitors of human cytomegalovirus (HCMV) replication that block viral DNA maturation via HCMV gene products UL89 and UL56. To determine if phosphorylation is required for antiviral activity, the in vitro metabolism of BDCRB was examined and the antiviral activities of nonphosphorylatable 5'-deoxy analogs were determined. Reverse-phase high-performance liquid chromatography (HPLC) analysis of extracts from uninfected and HCMV-infected cells incubated with [(3)H]BDCRB revealed two major metabolites. Both were less polar than naturally occurring nucleoside monophosphates, but one peak coeluted with a BDCRB-5'-monophosphate (BDCRB-5'-MP) standard. Further analysis revealed, however, that neither metabolite partitioned with BDCRB-5'-MP on anion-exchange HPLC. Their retention patterns were not affected by incubation with alkaline phosphatase, thereby establishing that the compounds were not nucleoside 5'-monophosphates. Both compounds were detected in uninfected and HCMV-infected cells and in mouse live extracts, but neither has been identified. Like TCRB and BDCRB, the nonphosphorylatable 5'-deoxy analogs were potent and selective inhibitors of HCMV replication. The 5'-deoxy analogs maintained inhibition of HCMV replication upon removal of BDCRB, whereas an inhibitor of DNA synthesis did not. Similar to TCRB, its 5'-deoxy analog (5'-dTCRB) did not affect viral DNA synthesis, but 5'-dTCRB did inhibit viral DNA maturation to genome-length units. Additionally, virus isolates resistant to TCRB were also resistant to 5'-dTCRB and the 5'-deoxy analog of BDCRB. Taken together, these results confirm that TCRB, BDCRB, and their 5'-deoxy analogs have common mechanisms of action and establish that these benzimidazole ribonucleosides, unlike other antiviral nucleosides, do not require phosphorylation at the 5' position for antiviral activity.     

Induction of virus-specific modifications recognized by cytotoxic T cells is not altered by prior substitution of target cells with trinitrophenol

Cytotoxic thymus-derived lymphocytes generated after interaction with trinitrophenyl (TNP)-substituted or virus-infected cells only lyse H-2 compatible target cells modified with the component used to immunize (TNP or virus). Prior saturation of TNP-reactive sites inhibits neither the infectivity of influenza A viruses, nor the capacity of infected cells to develop antigenic changes recognized by influenza-immune T cells. The two antigens are distinct entities on the cell membrane and do not obviously compete to form interactions with H-2 molecules.     

Local proteolytic activation after pulmonary trauma is not prevented by high dose steroids

Local trauma to the lungs induces a temporary permeability disturbance with reduction in the osmotic reflection coefficient of a sheep lung lymph model. Proteolytic enzymes may be involved in this microvascular injury. In the present study, we tested the hypothesis that pretreatment with methylprednisolone prevents activation of proteolytic systems after pulmonary trauma and that these systems are of etiological importance in the development of the pulmonary lesion. Central markers of proteolytic cascade systems were monitored in sheep subjected to local trauma to the lungs (lung lymph fistula preparation) with (n = 7) or without (n = 7) methylprednisolone (30 mg/kg) pretreatment. In control animals, reduced levels of prothrombin, antithrombin, kallikrein inhibitors, antiplasmin, and increased level of plasminogen activator inhibitor (PAI) indicated systemic activation of the coagulation, kallikrein-kinin, and fibrinolytic systems. These changes, except for PAI, were more pronounced in lung lymph. High levels of thromboxane A2 and 6-keto prostaglandin F1 alpha were found in lymph. In steroid-pretreated animals, the prostanoid response was attenuated, but all other variables were similar to control animals; thus, steroids did not prevent either local or systemic proteolytic enzyme activation caused by local trauma to the lung. The etiological role of this activation in the development of lung lesion has not yet been evaluated.     

Taurine prevents apoptosis induced by high ambient glucose in human tubule renal cells.

BACKGROUND: Hyperglycemia selectively triggers apoptosis in tubule and endothelial cells. Taurine, a conditionally essential amino acid, is abundant in several tubule segments, but its role has not been defined fully. It can serve as an osmolyte or as an endogenous antioxidant. Taurine metabolism is altered in diabetes mellitus, with extracellular and intracellular pools reduced. It is still unknown whether taurine can play a role as a protective agent in apoptosis induced by high glucose in tubular cells. METHODS: Apoptosis (by annexin V binding and the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling method), cellular reactive oxygen species (ROS) formation (by fluorescent probe 2'-7' dichlorofluorescin diacetate and FACScan flow cytometry), and Bcl-2 and Bax proteins (by immunostaining) were studied in a human proximal tubular cell line (HK-2) grown in a medium with physiologic (5.5 mM) or high (30 mM) glucose concentrations for 48 hours. In separate experiments, taurine (3-24 mM) was added to the media. RESULTS: The exposure of human tubule cells to 30 mM glucose for 48 hours resulted in a significant increase in apoptosis compared with 5.5 mM glucose (35 +/- 8% vs. 6 +/- 3%, p < 0.001). Thirty mM mannitol failed to induce the effects of high glucose. High glucose-mediated apoptosis was associated with a decrease in the expression of Bcl-2 (-87%) and a twofold increase in the expression of Bax protein. Taurine had a dose-dependent effect in preventing high-glucose-induced apoptosis (-78%, p < 0.001 at 24 mM). Moreover, with taurine, intracellular ROS decreased by 34% (p < 0.05), and changes in intracellular ROS formation induced by taurine at 24 hours predicted the variations in the apoptotic index at 48 hours (r = 0.87, p < 0.02). Other antioxidants, such as glutathione and N-acetylcysteine, also attenuated the high glucose-induced apoptosis. CONCLUSION: These results demonstrate that taurine attenuates hyperglycemia-induced apoptosis in human tubular cells via an inhibition of oxidative stress. Taurine might act as an endogenous antioxidant in tubule cells and could exert a beneficial effect in preventing tubulointerstitial injury in diabetic nephropathy.     

Leisure time but not occupational physical activity significantly affects cardiovascular risk factors in an adult population

BACKGROUND: A large number of studies have demonstrated that regular physical activity during leisure time (LTPA) accounts for a significant protection against cardiovascular diseases (CVD). On the other hand, conflicting findings on the beneficial effects of occupational physical activity (OPA) have been reported. The aim of this study is to evaluate the possible influence of different amounts of LTPA and OPA on circulating levels of several parameters associated with an increased risk of CVD. MATERIALS AND METHODS: We studied 932 individuals (365 M; 567 F, with a mean age of 54 years) living in Florence, Italy, who were enrolled in a population study conducted between 2002 and 2004. Subjects were divided into three classes of LTPA and OPA according to a score derived from a questionnaire that assessed the amount of physical activity performed. RESULTS: LTPA was inversely related to body mass index (BMI), hip circumference, diastolic blood pressure and triglycerides, as well as directly correlated with high-density lipoprotein (HDL) cholesterol. Likewise, a higher OPA was found to be associated with higher HDL cholesterol levels. Moreover, a multivariate logistical regression analysis, adjusted for possible confounders, showed that a moderate-to-high intensity of LTPA was able to confer a significant protection against having abnormal levels of BMI, waist circumference and triglycerides, main features of the metabolic syndrome, whereas no associations between these parameters and OPA were observed. CONCLUSIONS: A moderate-to-high LTPA was found to be significantly associated with a more favourable cardiovascular risk profile in terms of anthropometric, metabolic and lipid parameters among an Italian population. In addition, a relationship between OPA and HDL-cholesterol was reported.     

Theophylline pharmacokinetics are not altered by lansoprazole in CYP2C19 poor metabolizers.

Lansoprazole is a potent gastric proton pump inhibitor that is metabolized by CYP2C19 but appears to induce the activity of hepatic microsomal CYP1A2 in a concentration-dependent manner. Because the inducing effect appears to be a dose-dependent phenomenon, it may be more important in poor metabolizers of CYP2C19 who have more than four times the area under the lansoprazole plasma concentration-time curve (AUC) and constitute 12% to 23% of Asian populations. Theophylline owes a significant portion of its metabolism to CYP1A2 and can cause gastric acid reflux that calls for concurrent use of proton pump inhibitors. We conducted a prospective, randomized, subject-blind, multicenter crossover study of the effect of multiple high-dose oral lansoprazole (30 mg twice a day for 7 days) on the pharmacokinetics of a single intravenous dose of theophylline (4.73 mg/kg) in healthy volunteers characterized for CYP2C19 genotype. The study compared the pharmacokinetics of lansoprazole and theophylline in five white extensive metabolizers, six Korean extensive metabolizers, and seven poor metabolizers of CYP2C19. The pharmacokinetics of lansoprazole were significantly different among groups; AUC values were 1.55+/-0.20 microg x h/mL in white extensive metabolizers, 7.01+/-0.72 microg x hr/mL in Korean extensive metabolizers, and 14.34+/-2.60 microg x h/mL in poor metabolizers (P < .001). The administration of lansoprazole did not change intravenous theophylline clearance compared with placebo in any group, and theophylline clearance exhibited no correlation with AUC of lansoprazole (rs = 0.12; P > .1). These data suggest that usual therapeutic doses of lansoprazole have no clinically significant influence on the clearance of theophylline, even in poor metabolizers of CYP2C19.     

Relationship between ventilation and breathlessness during exercise in chronic obstructive airways disease is not altered by prevention of hypoxaemia

We have examined the hypothesis that hypoxaemia contributes to breathlessness by a mechanism distinct from its action as a ventilatory stimulant. Five patients who developed arterial oxygen desaturation during incremental exercise were studied. Exercise tests were performed on a cycle-ergometer. Breathlessness was measured by using a visual analogue scale technique. All five patients had considerable previous experience of these procedures. Two identical exercise tests were performed by each patient, breathing either room air or 60% oxygen in a blind randomized study. Breathing air, arterial saturation at rest was 93% and fell by 7% during exercise. Breathing 60% oxygen, resting saturation was 98% and there was no fall during exercise. Breathing oxygen, ventilation for a given work load was reduced and exercise duration was increased when compared with air breathing. In each of the five patients the relationship between breathlessness and minute ventilation was the same whether breathing air or 60% oxygen, despite the reduction in ventilation for a given work rate.