Neutron off-plane scattering of aligned membranes. I. Method Of measurement

We describe a method of measuring neutron scattering of aligned membranes with the momentum transfer oriented parallel or partly perpendicular to the plane of the membranes. The method obtains the complete information for the structures within fluid membranes obtainable by scattering. Data from alamethicin- and magainin-induced pores are presented. Although the in-plane scattering curves of these two peptides are similar to each other, their off-plane scattering patterns are strikingly distinct. Magainin pores exhibit intermembrane correlations.     

Donor liver selection. The South-Eastern Organ Procurement Foundation Liver Committee

OBJECTIVE: To investigate the effectiveness of noninvasive (face mask) versus invasive (endotracheal tube) equal pressure values on blood gases and respiratory pattern and to evaluate the feasibility of using mask ventilation after the short term physiologic study. DESIGN: Open, prospective, physiologic study and uncontrolled clinical study. SETTING: Intensive care unit of a trauma center. PATIENTS: 22 intubated trauma patients were studied. INTERVENTIONS: Patients were intubated and ventilated in a pressure support mode (IPSV) of 13.5 +/- 1.5 cmH2O and a post end-expiratory pressure (PEEP) of 5.8 +/- 2.57 cmH2O. After a T-piece trial to assess patient's ability to breath spontaneously, patients were switched over to noninvasive pressure support (NIPSV). The pressure levels were set as during IPSV. Blood gases and respiratory parameters were measured during IPSV, during the T-piece trial, and after 1 h of NIPSV. After the physiologic study, all patients were asked if they wished to continue on NIPSV. The patient's subjective compliance with IPSV and NIPSV was measured by means of an arbitrary score. A successful outcome was defined as no need for reintubation. MEASUREMENTS AND RESULTS: IPSVand NIPSV showed no statistical differences for blood gas and respiratory parameters by using the same values of PSV (13 +/- 5 vs 12.8 +/- 1.7 cmH2O, NS) and PEEP (5.8 +/- 2.5 and 5.2 +/- 2.2 cmH2O NS). The median length of time on NIPSV was 47 h (range 6 to 144). All patients wished to continue on NIPSV, but 9 patients (40.9%) were reintubated after 54 +/- 54 h. Six of them died after 36 +/- 13 days while still on mechanical ventilation. There was no statistically significant difference in compliance score between IPSVand NIPSV. CONCLUSIONS: NIPSV is comparable to IPSV in terms of blood gases and respiratory pattern. The clinical uncontrolled study indicates that NIPSV could be used in selected trauma patients.     

Clinical measurement of swallowing in health and in neurogenic dysphagia

Matrix vesicles are extracellular organelles produced by cells that mineralize their matrix. They contain enzymes that are associated with calcification and are regulated by vitamin D metabolites in a cell maturation-dependent manner. Matrix vesicles also contain metalloproteinases that degrade proteoglycans, macromolecules known to inhibit calcification in vitro, as well as plasminogen activator, a proteinase postulated to play a role in activation of latent TGF-beta. In the present study, we examined whether matrix vesicle metalloproteinase and plasminogen activator are regulated by 1, 25(OH)2D3 and 24,25(OH)2D3. Matrix vesicles and plasma membranes were isolated from fourth passage cultures of resting zone chondrocytes that had been incubated with 10(-10)-10(-7) M24, 25(OH)2D3 or growth zone chondrocytes incubated with 10(-11)-10(-8) M 1,25(OH)2D3, and their alkaline phosphatase, active and total neutral metalloproteinase, and plasminogen activator activities determined. 24,25(OH)2D3 increased alkaline phosphatase by 35-60%, decreased active and total metalloproteinase by 75%, and increased plasminogen activator by fivefold in matrix vesicles from resting zone chondrocyte cultures. No effect of vitamin D treatment was observed in plasma membranes isolated from these cultures. In contrast, 1,25(OH)2D3 increased alkaline phosphatase by 35-60%, but increased active and total metalloproteinase three- to fivefold and decreased plasminogen activator by as much as 75% in matrix vesicles isolated from growth zone chondrocyte cultures. Vitamin D treatment had no effect on plasma membrane alkaline phosphatase or metalloproteinase, but decreased plasminogen activator activity. The results demonstrate that neutral metalloproteinase and plasminogen activator activity in matrix vesicles are regulated by vitamin D metabolites in a cell maturation-specific manner. In addition, they support the hypothesis that 1,25(OH)2D3 regulation of matrix vesicle function facilitates calcification by increasing alkaline phosphatase and phospholipase A2 specific activities as well as metalloproteinases which degrade proteoglycans.     

The necessity of voiding cystourethrogram in the pretransplant urologic evaluation

OBJECTIVES: To determine the efficacy of limited use of voiding cystourethrogram (VCUG) in the evaluation of patients for renal transplantation. METHODS: A retrospective review of 439 patients who underwent renal transplantation between October 1983 and May 1995; however, since September 1993 we used VCUG selectively in the pretransplant evaluation. RESULTS: Since September 1993, only 51% of our renal transplant patients had a VCUG as part of their pretransplant evaluation . Only one urologic complication has occurred in a 68-year-old man with a history of glomerulonephritis. He had an episode of acute urinary retention, which was treated successfully with a temporary suprapubic tube followed by medical therapy. CONCLUSIONS: Our preliminary results reveal no adverse outcomes associated with the selective use of VCUG in the pretransplant evaluation, and indicate that this study is of little value in the routine evaluation of these patients.     

Plasmodium falciparum and P. vivax circumsporozoite proteins in anophelines (Diptera: Culicidae) collected in eastern Thailand

In total, 414 anophelines, consisting of Anopheles karwari (James), An. splendidus Koidzumi, An. dirus Peyton & Harrison, and An. barbirostris Van der Wulp were collected in 2 provinces in eastern Thailand and tested by enzyme-linked immunosorbent assay for the presence of circumsporozoite proteins. Plasmodium vivax CS protein was detected in 3.4% (2/54) of An. karwari and 4.8% (2/42) of An. barbirostris specimens. Both P. vivax phenotypes, Pv247 and Pv210, were found in An. karwari, whereas only Pv247 was detected in An. barbirostris. Plasmodium falciparum CS protein was detected only in 0.3% (1/276) of An. dirus. Results indicate that An. barbirostris may play a role in the transmission of P. vivax in Chanthaburi Province, Thailand.     

Helicobacter pylori colonization of Barrett's esophagus and its progression to cancer

Helicobacter pylori (HP) plays a crucial role in gastric carcinogenesis. Few studies have looked at the relationship between HP and Barrett's esophagus/cancer. To further investigate this, a study comparing the prevalence of HP and increasing grades of dysplasia was undertaken. Biopsies from 19 malignant and 94 benign cases of Barrett's esophagus were analysed histologically for the presence of HP. 34% of non-dysplastic Barrett's epithelium was colonized with HP compared with only 17% of dysplastic/malignant cases (P = 0.04). No relationship was found between HP status and: (i) length of Barrett's esophagus; (ii) the presence of ulcers or strictures; and (iii) previous anti-reflux surgery. HP colonization of Barrett's esophagus is not uncommon. We found that HP has a negative correlation with increasing dysplasia which is analogous to gastric carcinogenesis. This finding should be investigated in prospective studies to elucidate its role in Barrett's adenocarcinoma.     

Development and evaluation of a predictive model for the effect of temperature and water activity on the growth rate of Vibrio parahaemolyticus

The growth rates of four strains of Vibrio parahaemolyticus were measured and compared in a model broth system. The results for the fastest growing strain, based on 77 combinations of temperature and water activity (aw) using NaCl as the humectant, were summarised in the form of a predictive mathematical model. The model, of the square-root type includes a novel term to describe the effects of super-optimal water activity, and can be used to predict generation times for the temperature range (8-45 degrees C) and water activity range (0.936-0.995) which permit growth of Vibrio parahaemolyticus. Predicted generation times from the model were compared to literature data, using bias and accuracy factors, for both laboratory media and foods. The model was shown to give realistic growth estimates, with a bias value of 1.01, and an accuracy factor of 1.38.     

Magnetic resonance imaging of the normal mouse brain: comparison with histologic sections

Details in the living animal can be compared with respective histologic section taken after death. In less than 35 min, 12 to 16 coronal and transverse images through the brain can be obtained, each with an in-plane resolution of 100 x 200 microns and a slice thickness of 900 microns. The experimental parameters can be manipulated not only to achieve different tissue contrast but also to access any desired plane.