Endothelial caveolae have the molecular transport machinery for vesicle budding, docking, and fusion including VAMP, NSF, SNAP, annexins, and GTPases

Transport by discrete vesicular carriers is well established at least in part because of recent discoveries identifying key protein mediators of vesicle formation, docking, and fusion. A general mechanism sensitive to N-ethylmaleimide (NEM) is required for the transport of a divergent group of vesicular carriers in all eukaryotes. Many endothelia have an abundant population of non-coated plasmalemmal vesicles or caveolae, which have been reported with considerable controversy to function in transport. We recently have shown that like other vesicular transport systems, caveolae-mediated endocytosis and transcytosis are inhibited by NEM (Schnitzer, J. E., Allard, J., and Oh, P. (1995) Am. J. Physiol. 268, H48-H55). Here, we continue this work by utilizing our recently developed method for purifying endothelial caveolae from rat lung tissue (Schnitzer, J. E., Oh, P., Jacobson, B. S., and Dvorak, A. M. (1995) Proc. Natl. Acad. Sci. U. S. A. 92, 1759-1763) to show that these caveolae contain key proteins known to mediate different aspects of vesicle formation, docking, and/or fusion including the vSNARE VAMP-2, monomeric and trimeric GTPases, annexins II and VI, and the NEM-sensitive fusion factor NSF along with its attachment protein SNAP. Like neuronal VAMPs, this endothelial VAMP is sensitive to cleavage by botulinum B and tetanus neurotoxins. Caveolae in endothelium are indeed like other carrier vesicles and contain similar NEM-sensitive molecular machinery for transport.     

Controlling Legionella in hospital water systems: experience with the superheat-and-flush method and copper-silver ionization

OBJECTIVE: To evaluate the effect of copper-silver ionization on Legionella colonization and nosocomial legionnaires' disease and to compare the efficacy of metal ions versus the superheat-and-flush method of disinfection. DESIGN: Prospective determination over a 36-month period of copper and silver ion concentrations in the recirculating hot-water system, Legionella colonization of the hospital water distribution system, and cases of nosocomial legionnaires' disease. Retrospective comparison of results with the previous 13 years, during which the superheat-and-flush method was used. SETTING: The Pittsburgh Veterans' Affairs Health Care System (University Drive Division) acute-care hospital. INTERVENTION: Three copper-silver ionization systems were installed on the hot-water distribution system in November 1994. RESULTS: The average number of cases of legionnaires' disease per year and the percentage of distal sites positive for Legionella pneumophila for the superheat-and-flush method versus the copper-silver ionization method was six cases with 15% positivity versus two cases with 4% positivity, respectively. The reduction in Legionella colonization after copper-silver ionization was significant (P<.05) compared to the superheat and flush. Mean copper and silver ion concentrations (mg/L) were 0.29 and 0.054 from hot-water tanks, and 0.17 and 0.04 from distal outlets, respectively. CONCLUSIONS: We conclude that a properly maintained and monitored copper-silver ionization system was more effective than the superheat-and-flush method for reducing the recovery of Legionella from the hospital water distribution system.     

Hailey-Hailey disease keratinocytes: normal assembly of cell-cell junctions in vitro

The blisters in the inherited disorder, Hailey-Hailey disease, may be caused by defective epidermal junctional complexes. We evaluated these structural complexes in vivo and in vitro. We induced a vesicular lesion in the apparently normal skin of a patient with Hailey-Hailey disease and studied a biopsy of this lesion by transmission electron microscopy. To determine whether acantholysis was related to a defect in the number or assembly of intercellular junctions, we cultured Hailey-Hailey disease keratinocytes in medium containing 0.1 mM Ca2+ and increased the [Ca2+] to 1.1 mM in order to induce assembly of cell-cell junctions. Keratinocytes were examined by double immunofluorescence with antibodies to the desmosome protein, desmoplakin, and the adherens junction protein, vinculin, at intervals after the increase in [Ca2+]. Characteristic Hailey-Hailey disease histopathology was observed by electron microscopy of the patient's skin after trauma, but we found no splitting of desmosomes. Based on the location, intensity, and rate of change of immunofluorescent staining, Hailey-Hailey and normal keratinocytes did not differ in their ability to assemble desmosomes and adherens junctions. Furthermore, we observed no significant morphologic differences between normal and Hailey-Hailey keratinocytes cultured in low and high [Ca2+]-containing media; Hailey-Hailey cells contained abundant normal-appearing desmosomes in 1.1 mM [Ca2+]. Since Hailey-Hailey disease keratinocytes can assemble normal-appearing adherens junctions and desmosomes in vitro, the functional defect may not lie in assembly of cell-cell adhering junctions, or additional perturbation may be required to expose the defect.     

Double-blind, placebo-controlled study of the effects of carvedilol in patients with moderate to severe heart failure. The PRECISE Trial. Prospective Randomized Evaluation of Carvedilol on Symptoms and Exercise

BACKGROUND: Carvedilol has improved the symptomatic status of patients with moderate to severe heart failure in single-center studies, but its clinical effects have not been evaluated in large, multicenter trials. METHODS AND RESULTS: We enrolled 278 patients with moderate to severe heart failure (6-minute walk distance, 150 to 450 m) and a left ventricular ejection fraction < or = 0.35 at 31 centers. After an open-label, run-in period, each patient was randomly assigned (double-blind) to either placebo (n = 145) or carvedilol (n = 133; target dose, 25 to 50 mg BID) for 6 months, while background therapy with digoxin, diuretics, and an ACE inhibitor remained constant. Compared with placebo, patients in the carvedilol group had a greater frequency of symptomatic improvement and lower risk of clinical deterioration, as evaluated by changes in the NYHA functional class (P = .014) or by a global assessment of progress judged either by the patient (P = .002) or by the physician (P < .001). In addition, treatment with carvedilol was associated with a significant increase in ejection fraction (P < .001) and a significant decrease in the combined risk of morbidity and mortality (P = .029). In contrast, carvedilol therapy had little effect on indirect measures of patient benefit, including changes in exercise tolerance or quality-of-life scores. The effects of the drug were similar in patients with ischemic heart disease or idiopathic dilated cardiomyopathy as the cause of heart failure. CONCLUSIONS: These findings indicate that, in addition to its favorable effects on survival, carvedilol produces important clinical benefits in patients with moderate to severe heart failure treated with digoxin, diuretics, and an ACE inhibitor.     

Neuroblastoma in Europe: differences in the pattern of disease in the UK. SENSE. Study group for the Evaluation of Neuroblastoma Screening in Europe

BACKGROUND: Neuroblastoma is a major contributor to childhood cancer mortality, but its prognosis varies with age and stage of disease, and some tumours regress spontaneously. Urinary screening programmes or clinical examination may detect the disease before symptoms appear, but the benefit of early diagnosis is uncertain. We examined the incidence, pattern, and presentation of neuroblastoma in four European countries. METHOD: Population-based incidence rates were derived for France, Austria, Germany, and the UK. Age, sex, and stage distribution were analysed by Mantel-Haenszel techniques and Poisson regression. The proportion of incidental diagnoses (cases without symptoms found at routine health checks or during investigation of other disorders) and mortality rates were also compared. FINDINGS: Between 1987 and 1991, 1672 cases of neuroblastoma were diagnosed in children under 15 years old (France, 624; Austria, 69; Germany, 493; UK, 486). Age-standardised annual incidence was significantly lower in the UK (10.1/million) than in France (12.5) and Germany (11.4). In the UK a deficit of low-stage disease in infants was accompanied by an excess of stage IV in older children. The UK had significantly fewer incidental diagnoses (8%) than Austria (27%) and Germany (34%). UK mortality rates were significantly higher than German or French rates. INTERPRETATION: In the UK, neuroblastoma diagnosis is delayed, possibly because of a less rigorous system of health checks for children. Although some overdiagnosis occurs in mainland Europe, our data suggest that in the UK some low-stage cases, undetected in infancy, may later present as advanced disease. This finding has implications for screening programmes and organisation of routine surveillance of infant health in the UK.     

Interactions of African American infants and their mothers: relations with development at 1 year of age

The relationships between aspects of mother-infant interaction and both communication and cognitive skills at 1 year of age were examined in 92 African American dyads, of whom 64 (70%) fell below the poverty line. Ratings of warmth, sensitivity, responsiveness, encouragement of initiative, stimulation, and elaborativeness during a semistructured play interaction were correlated with measures of global cognition, expressive and receptive communication, and communication use. The overall quality of the home environment and maternal ratings of stimulation and elaborativeness were the most consistent correlates of infant communication measures. Relationships were stronger in middle-income than lower-income dyads. These results support the linkage of didactic and functional aspects of maternal behavior to cognitive and communication skills at 1 year of age for African American infants.     

Downward movement of nitrate and ammonium nitrogen in a flatland ultisol

Three field trials were conducted in the early and late rainy season on a Piarco Series soil (Aquoxic Tropudults) in Central Trinidad to monitor downward movement of NH ₄ ⁺ -N and NO ₃ ^- -N under flat-tilled and ridge-tilled conditions as affected by mulch application. The first experiment was carried out in the early rainy season under bare-fallowed conditions, while okra (Abelmoschus esculentus) was the test crop used in the two remaining trials, which were conducted during the early and late rainy season periods. The plots were fertilized with urea seven days after crop emergence and 14 days after land preparation for the cropped and bare-fallowed experiments respectively. Soil samples were collected weekly after fertilizer application and analyzed for NH ₄ ⁺ -N, NO ₃ ^- -N and soil water.Urea application increased NH ₄ ⁺ -N levels in the soil and NH ₄ ⁺ -N was the dominant inorganic N form observed for the first four weeks after fertilization. Mulch application decreased NH ₄ ⁺ -N and NO ₃ ^- -N soil levels. Ridging the soil increased downward movement of NH ₄ ⁺ -N and NO ₃ ^- -N. Under bare-fallowed conditions, downward movement of NH ₄ ⁺ -N was noted in the 30 to 45 cm soil layer at seven days after fertilization, while under cropped conditions its movement was restricted to the 15 to 30 cm layer within the same period. In bare-fallowed soil, increased NO ₃ ^- -N and its downward movement was noted after four weeks of fertilization. In the cropped soil, downward movement of NO ₃ ^- -N was observed one week after fertilization in the early rainy season and three weeks after fertilization in the late rainy season.     

Volumetric flow rate comparisons for water and product on pasteurization systems

A flow calibration tube system was assembled to determine the volumetric flow rates for water and various dairy products through a holding tube, using three different flow promotion methods. With the homogenizer, the volumetric flow rates of water and reconstituted skim milk were within 1.5% of each other. With the positive displacement pump, the flow rate for reconstituted skim milk increased compared with that for water as the pressure increased or temperature decreased. The largest increase in flow rate was at 310-kPa gauge and 20 degrees C. On a magnetic flow meter system, the volumetric flow rates of water and reconstituted skim milk were within .5% of the flow rate measured from the volume collected in a calibrated tank. The flow rate of whole milk was similar to that of skim milk on the three flow promoters evaluated. Ice milk mix increased the flow rate of the positive displacement pump, but not the homogenizer and magnetic flow meter system.