Pulmonary surfactant and its components inhibit secretion of phosphatidylcholine from cultured rat alveolar type II cells

Pulmonary surfactant is synthesized and secreted by alveolar type II cells. Radioactive phosphatidylcholine has been used as a marker for surfactant secretion. We report findings that suggest that surfactant inhibits secretion of 3H-labeled phosphatidylcholine by cultured rat type II cells. The lipid components and the surfactant protein group of Mr 26,000-36,000 (SP 26-36) inhibit secretion to different extents. Surfactant lipids do not completely inhibit release; in concentrations of 100 micrograms/ml, lipids inhibit stimulated secretion by 40%. SP 26-36 inhibits release with an EC50 of 0.1 microgram/ml. At concentrations of 1.0 microgram/ml, SP 26-36 inhibits basal secretion and reduces to basal levels secretion stimulated by terbutaline, phorbol 12-myristate 13-acetate, and the ionophore A23187. The inhibitory effect of SP 26-36 can be blocked by washing type II cells after adding SP 26-36, by heating the proteins to 100 degrees C for 10 min, by adding antiserum specific to SP 26-36, or by incubating cells in the presence of 0.2 mM EGTA. SP 26-36 isolated from canine and human sources also inhibits phosphatidylcholine release from rat type II cells. Neither type I collagen nor serum apolipoprotein A-1 inhibits secretion. These findings are compatible with the hypothesis that surfactant secretion is under feedback regulatory control.     

Exhalation time effects on arterial and venous blood oxygen content and arterial PCO2 during high frequency jet ventilation of surfactant-depleted cats

Since high frequency jet ventilation (HFJV) relies on lung mechanics for the passive removal of expiratory gas, one would predict that the time allowed for exhalation would have serious effects on cardiopulmonary function. To document these effects we lavaged the lungs of ten cats with 30 ml/kg of saline six times, then sampled arterial and venous blood while the animals were ventilated conventionally at 30 BPM and then with HFJV at 600 BPM, varying inspiratory/expiratory ratios (I/E) from 1:1 to 1:5. The animals breathed 100% O2 throughout the study, and the mean airway pressure was held constant for each animal when the I/E was varied during HFJV. Decreasing the I/E from 1:1 to 1:5 during HFJV resulted in an increase of arterial oxygen content (Cao2) from 11.3 +/- 1.2S E to 13.6 +/- 1.2 ml O2/100 ml blood (P less than 0.01), a decrease of PaCO2 from 43 +/- 6 to 27 +/- 4 mm Hg, and an increase of alveolar to arterial oxygen gradient from 351 +/- 49 to 377 +/- 49 mm Hg. The ratio of systemic blood flow to oxygen consumption (Q/VO2) was similar during conventional ventilation and with HFJV at I/E of 1:1 (18.9 +/- 3.7 vs 18.0 +/- 2.9) but decreased when I/E was reduced to 1:5 during HFJV (13.9 +/- 2.1). The ratio of the product of CaO2 and Q (systemic oxygen availability) to VO2 (SO2 T/VO2) remained unchanged during all modes of ventilation (1.75 +/- 0.15). The increase in CaO2 observed when I/E was reduced from 1:1 to 1:5 during HFJV was counterbalanced by a decrease in Q/VO2 such that SO2 T/VO2 remained relatively constant.     

Human T-cell lymphotropic virus-III (HTLV-III) seropositivity and related disease among 71 consecutive patients in whom tuberculosis was diagnosed. A prospective study

The incidence of tuberculosis has recently risen in Southeast Florida. In order to determine the number and proportion of tuberculosis cases and the characteristics of tuberculosis that might be related to human T-cell lymphotrophic virus-III (HTLV-III) infection, all patients seen by the Dade County Florida Public Health Department-Tuberculosis Clinic during a 6-month period were medically evaluated and screened for HTLV-III antibody by an enzyme-linked immunosorbent assay. Of 71 consecutive patients confirmed to have tuberculosis (70 by culture) during the study period, 22 (31%) were seropositive and 49 (69%) were seronegative for HTLV-III antibody. The seropositive group had a significantly higher proportion of patients who were black, Haitian, and within the age group of 25 to 44 yr. The seropositive group also had a significantly higher rate of mild-to-moderate serum aspartate transaminase elevations (less than or equal to 5 times normal), tuberculin skin test false negativity, extrapulmonary tuberculosis (especially lymphatic), and pulmonary tuberculosis with an atypical radiographic picture. The seropositive group had a significantly lower proportion of patients with sputum cultures positive for M. tuberculosis. There was no significant difference between the groups with respect to the proportion of patients with positive sputum smears when sputum cultures were positive, serious antituberculosis drug reactions (requiring discontinuation of therapy), or percent of home contacts who were tuberculin skin tested and found to be positive. At the time of the diagnosis of tuberculosis, only 6 (27%) of the seropositive patients with tuberculosis had clinical evidence of AIDS or AIDS-related complex (unexplained thrush).(ABSTRACT TRUNCATED AT 250 WORDS)     

Osteoarticular and muscle infectious lesions in patients with the human immunodeficiency virus

Summary Between 1988 and 1995, 1832 HIV positive patients were evaluated in our institution. We studied the epidemiologic, immunologic and bacteriologic data, laboratory tests, and X-Ray films in those with musculoskeletal infection. We reviewed twenty-one cases of musculoskeletal infection in twenty patients aged 23–35 years (mean 28,6 years, M:F=15:5). In all of them risk factor for HIV was intravenous drug abuse. The number of CD4 positive lymphocytes ranged from 0,003 to 0,5 10⁹/l. Staphylococcus aureus was the organism responsible of the infection in twelve cases, all active intravenous drug abusers at the time the diagnosis was done. The remaining causative agents were: Mycobacterium tuberculosis (3 cases), Candida albicans (2 cases), Salmonella subgroup 1 (1 case), Neisseria gonorrhoeae (1 case), Pseudomona aeruginosa (1 case) and Streptococcus agalactiae (1 case). Fifteen infections were diagnosed between 1988 and 1991 and 6 between 1992 and 1995. Musculoskeletal infectious lesions in HIV positive patients in our country are related in the majority of cases to intravenous drug abuse. In the last four years due to a National medical health care plan conducted to educate this group of people the number of musculoskeletal infections is decreasing.     

Evidence of active efflux in resistance to ciprofloxacin and to ethidium bromide by Mycoplasma hominis

The uptake of fluoroquinolones was characterized for the fluoroquinolone-susceptible strain PG21 of Mycoplasma hominis. Accumulation of fluoroquinolones appeared to occur by passive diffusion. Addition of arginine as the energizer significantly reduced the uptake of fluoroquinolones, suggesting the presence of an energy-dependent efflux process. Reserpine and orthovanadate, two multidrug pump inhibitors, increased significantly the ciprofloxacin (CIP) uptake. In contrast, such a strong effect was not observed for moxifloxacin and pefloxacin uptakes. Two ethidium bromide (EtBr)-resistant strains, selected in vitro, showed a resistance profile compatible with a multidrug-resistant phenotype, with increased MICs for the hydrophilic fluoroquinolones, CIP and norfloxacin, EtBr, and acriflavine. Taking the EtBr-resistant strain RB1La as a model, a significant decrease of the CIP and EtBr uptakes was observed compared to the reference strain PG21. In the presence of reserpine and orthovanadate, both inhibitors of ATP-dependent efflux pumps, the CIP uptake increased significantly, reaching approximately the same level as that of the susceptible strain. Similar results were obtained with EtBr uptake and efflux experiments. Our data suggest the presence of an active efflux system, possibly an ABC-type efflux pump, implicated in the resistance to CIP and unrelated compounds like EtBr in the human mycoplasma M. hominis.     

Video capsule endoscopy for previous overt obscure gastrointestinal bleeding in patients using anti‐thrombotic drugs

Background and Aim: Little is known about the causes of overt obscure gastrointestinal bleeding (OGIB) in patients using anti‐thrombotic therapy. We aimed to describe video capsule endoscopy (VCE) findings and to identify factors associated with positive findings in these patients. Methods: We carried out a retrospective study of 56 patients who underwent VCE for evaluation of previous overt OGIB during anti‐thrombotic therapy. VCE studies were re‐evaluated by a gastroenterologist blinded to clinical details. Clinical data included in the multivariate analysis were sex, age, indication for and type of anti‐thrombotic therapy, hemodynamic instability on admission, type of blood loss, hemoglobin on admission, use of a proton pump inhibitor, NSAID use, time between bleeding episodes and VCE, and whether or not anti‐thrombotic therapy was resumed before the VCE study. Results: A probable cause for gastrointestinal bleeding was identified in 28 (50%) of the 56 studies. Angiodysplasia was found in 19 patients. Twenty‐two studies showed a possible cause in the small bowel. Multivariate logistic regression analysis showed that reinstitution of anti‐thrombotic therapy before VCE was carried out was the only independent predictor of positive VCE findings (OR: 8.61, 95% CI: 1.20–60.42, P = 0.032). Conclusions: Small intestinal angiodysplasia was the most common cause for overt OGIB. Reinstitution of withdrawn anti‐thrombotic drugs before the VCE examination was carried out was associated with positive VCE findings in multivariate analysis.     

The role of torovirus in nosocomial viral gastroenteritis at a large tertiary pediatric centre

OBJECTIVE:

To describe the viral etiology and epidemiology of nosocomial viral gastroenteritis (NVG) at a tertiary care pediatric hospital and identify any changes over the past two decades.

METHODS:

Retrospective review of all patients with laboratory-confirmed NVG at The Hospital for Sick Children (Toronto, Ontario), from January 1, 2004, to December 31, 2005.

RESULTS:

One hundred forty-two episodes of NVG were found among 133 patients, occurring in 0.48 of 100 admissions. The median age was two years; 42% were <1 year of age and 41% were immunocompromised. The most commonly detected pathogen was torovirus (67% of episodes), followed by rotavirus (19%) and adenovirus (9%). Seventy-five cases (53%) were epidemiologically linked in 32 separate clusters (median cluster size two, range two to four). The NVG rate fell from 0.63 of 100 to 0.22 of 100 admissions after March 2005 (P<0.001) when enhanced infection control precautions were instituted in response to an outbreak of vancomycin-resistant Enterococcus.

CONCLUSIONS:

Torovirus remains the most commonly identified cause of NVG at The Hospital for Sick Children. Most NVG cases were epidemiologically linked, and a significant reduction in cases occurred after the institution of enhanced infection control practices following an outbreak of vancomycin-resistant Enterococcus. Improved education and surveillance for NVG should lead to further reduction in this problem.     

Crosstalk Between the Renin–Angiotensin System and the Advance Glycation End Product Axis in the Heart: Role of the Cardiac Fibroblast

Cardiac fibroblasts (CFs) are involved in maintaining extracellular matrix (ECM) homeostasis in the heart. CFs mediate responses to hormonal and mechanical stimuli and relay these to other local cell types through release of autocrine and/or paracrine factors. CFs also play important roles in the setting of injury, i.e., myocardial infarction, where ECM production is key to efficient scarring. However, conditions exist in which excess production of ECM by CFs can lead to cardiac fibrosis. Two important pathways known to be involved in development of cardiac fibrosis are renin?Cangiotensin system (RAS) and advanced glycation end products (AGE) receptor (RAGE) signaling cascades. This report summarizes actions of these two pathways on function of CFs. Because cardiac fibrosis is an important component of diabetic cardiomyopathy, we include new data that suggests a possible crosstalk between the RAS and AGE/RAGE pathway in order to activate CFs in diabetes.     

Qualitative comparison of coronary angiograms between 4 french catheters with an Advanced Cardiovascular Injection System and 6 french catheters with manual injection

Objectives: This study aimed to test whether advanced cardiovascular injection (ACI) via 4 French (Fr) catheters is more advantageous than manual injection with 6 Fr catheters. Background: For coronary angiography, proponents of contrast media ACI believe it utilizes smaller‐diameter catheters when compared with manual injection, without compromising the quality of the angiogram, and has the potential to reduce the amount of contrast used and lessen the use of closure devices. Methods: In a prospective study, 200 consecutive patients referred for elective coronary angiography were randomized to standard 6 Fr catheters with manual injection versus 4 Fr catheters with ACI. The study's primary endpoint is the quality of the coronary angiogram. Secondary endpoints include groin complications, utilization of closure devices, and volume of contrast media. Thirty‐six patients who underwent ad hoc percutaneous coronary intervention were excluded from the analysis. Results: The final analysis included 80 patients treated with 4 Fr catheters with ACI and 84 patients treated with 6 Fr catheters with manual injection. The groups had similar demographic and clinical characteristics. The quality of the angiogram was similar between groups with the exception of more left coronary sinus flush with 4 Fr catheters (3.57 ± 1.1 vs. 2.98 ± 0.9, P < 0.001) and less closure device use with 4 Fr (25 vs. 71.4%, P < 0.01) compared to 6 Fr catheters. The procedure duration, volume of contrast used, vascular complications, and time to ambulation were similar between groups (all P > 0.05). Conclusions: 4 Fr diagnostic catheters with ACI offer similar quality coronary angiograms, similar rates of vascular complications, procedure duration, contrast used, and time to ambulation, but have a significantly lesser need for closure devices compared to the 6 Fr system with manual injection. © 2011 Wiley‐Liss, Inc.     

Platypnea‐orthodeoxia Syndrome after Failed Percutaneous Closure of Secundum Atrial Septal Defect

We report a 51‐year‐old patient with platypnea‐orthodeoxia syndrome after percutaneous closure of a secundum atrial septal defect, an unusual complication of this modality of treatment. Echocardiography, the main diagnostic technique in the present case, showed that one of the percutaneous device's rims was fixed to the anterior wall of the inferior cava vein. Furthermore it showed that the blood flowed from the inferior cava vein, through the defect in the atrial septum, into the left atria.