Influence of chronic ethanol consumption on hamster liver microsomal O-dealkylase activities and cytochrome b5 content

The effects of two different methods of administering ethanol to hamsters on liver microsomal cytochrome levels and the activities of ethoxyresorufin O-deethylase and p-nitroanisole O-demethylase have been examined. Administration of ethanol in liquid diets resulted in enhanced levels of cytochrome P-450, NADPH-supported aniline hydroxylase (Form I), and both NADPH- and NADH-supported p-nitroanisole O-demethylase. NADH-ferricyanide reductase was also increased. No change in NADPH-cytochrome c reductase or in the NADPH-supported rate of ethoxyresorufin O-deethylase was observed. In contrast, both NADH-supported ethoxyresorufin O-deethylase and cytochrome b5 levels were decreased. Administration of ethanol in the drinking water to chow-fed animals had no effect on total cytochrome P-450 levels; however, the rates of NADPH-supported aniline hydroxylase (Form I) and p-nitroanisole O-demethylase activity were increased. No changes in NADPH-cytochrome c reductase, NADH-ferricyanide reductase, or NADH-supported p-nitroanisole O-demethylase activity were noted. Cytochrome b5 levels were decreased as were both the NADPH- and NADH-supported rates of ethoxyresorufin O-deethylase. These data suggest that chronic consumption of ethanol by hamsters either in liquid diet form or as ethanol-water solutions to chow-fed animals lowers cytochrome b5 levels. When cytochrome b5 levels are lowered and total chromosome P-450 levels remain unchanged, the NADPH-supported rate of microsomal O-dealkylation of ethoxyresorufin is decreased. These data suggest that cytochrome b5 participates in the NADPH-supported microsomal O-dealkylation of ethoxyresorufin.     

From conversion to aggregation: protofibril formation of the prion protein

The ability to diagnose and treat prion diseases is limited by our current understanding of the conversion process of the protein from healthy to harmful isoform. Whereas the monomeric, benign species is well characterized, the misfolded conformations responsible for infectivity and neurodegeneration remain elusive. There is mounting evidence that fibrillization intermediates, or protofibrils, but not mature fibrils or plaques, are the pathogenic species in amyloid diseases. Here, we use molecular dynamics to simulate the conversion of the prion protein. Molecular dynamics simulation produces a scrapie prion protein-like conformation enriched in β-structure that is in good agreement with available experimental data. The converted conformation was then used to model a protofibril by means of the docking of hydrophobic patches of the template structure to form hydrogen-bonded sheets spanning adjacent subunits. The resulting protofibril model provides a non-branching aggregate with a 3₁ axis of symmetry that is in good agreement with a wide variety of experimental data; importantly, it was derived from realistic simulation of the conversion process.     

Bowel vaginoplasty in children: a retrospective review

Background/purpose

There are numerous congenital genitourinary conditions that result in vaginal agenesis or atresia. Reconstruction presents a challenge to the surgeon who wishes long-term functional and cosmetic results with low morbidity. Historically, reconstruction has involved the use of skin grafts and nonoperative methods with less than ideal results. The preference of the authors is to use intestinal segments for creating the neovagina and herein review their experience with this procedure.

Methods

The authors identified 10 children who underwent vaginal construction with intestinal segments from 1996 to the present. Patient charts were reviewed for etiology, procedure performed, operative and postoperative complications, and follow-up.

Results

Average age at surgery was 10.9 years (1 to 29 years). Of the 10 children, 3 required vaginal construction for cloacal extrophy, and 7 had vaginal atresia of various etiology. Sigmoid colon was utilized in 6 cases, ileum in 2, and, in 2 patients with high imperforate anus, their mucous fistula segment was used to create the vagina. Mean follow-up was 24 months. Complications included a right ureteral injury necessitating placement of an indwelling ureteral stent and a girl presenting with cyclic pelvic pain who required reanastomosis of the neovagina to the uterus for an obstructed cervical os.

Conclusions

Intestinal segments can be used successfully for creation of a neovagina with exceptional cosmetic results and an acceptable complication rate. In appropriate patients, the mucous fistula can be used to create the vagina obviating the need for a bowel anastomosis.     

Improved contact lens electrode for corneal ERG recordings in mice

The electroretinogram (ERG) is routinely used to study retinal physiology in the clinic and in research. Due to their outstanding properties, contact lens electrodes (CLEs) are widely used for ERG recordings. Though the procedures for ERG recordings in mice are similar to those used in humans and larger vertebrates, use of CLEs in the mouse has been limited because of difficulties involved with the manufacturing of small contact lenses. We describe a simple instrument and method for manufacturing contact lenses and CLEs for stable ERG recordings in mice. The instrument operates like a hole-punch and is based on slip joint pliers incorporating a ball bearing on one jaw and forming plate on the other. These CLEs are simple to manufacture, inexpensive and provide stable, long-term recordings of corneal ERGs in mice. With minor modifications, these CLEs could be made for other small animals such as rats or fish.     

Magnetic resonance imaging study of the effects of age and accommodation on the human lens cross-sectional area

PURPOSE: To evaluate the effect of age and accommodation on lens cross-sectional area (CSA). METHODS: High-resolution magnetic resonance images of the eye were acquired from 25 subjects ranging in age from 22 to 50 years during accommodation and with accommodation at rest. The images were analyzed to obtain the total lens CSA and the CSAs of the anterior and posterior portions of the lens. RESULTS: The total lens CSA and the CSA of the anterior portion increased with age in both accommodative states. With accommodation, the CSA was larger in these portions of the lens; however, this difference decreased with age. Conversely, the CSA of the posterior portion of the lens remained statistically independent of both age and accommodative state. CONCLUSIONS: This preliminary study documents, in vivo, that the lens grows with age. This growth appears to be confined to the anterior portion. A quite unexpected finding is that both the total lens CSA and the CSA of the anterior portion are greater during accommodation when zonular tension is minimized. This accommodative change in CSA, which decreases with age, may be due to compression of the lens material during relaxed accommodation when zonular tension is greatest. That both age and accommodative changes in CSA appear to be limited to the anterior portion of the lens may be related to properties of the anterior capsule and lens material, the position of the zonular attachments, and the location of the fetal nucleus.     

Perceptions of senior baccalaureate nursing students and nurse leaders. A look at elements of success in the workplace

This article compares the perceptions of senior baccalaureate students and nurse leaders (administrators, managers, academic leaders, and advanced practice nurses) regarding the qualities that are needed to be successful in the current nursing shortage. The congruence between the two groups' responses validates the importance of valuing practice-oriented-education as well as the power within and between the education and practice arenas to strategize and solve problems together at a highly tumultuous time.     

Glutamine and barrier function in cultured Caco-2 epithelial cell monolayers

Dietary glutamine (Gln) has been shown to be important for maintenance of the intestinal barrier. To investigate the role of the epithelium in this Gln dependence, Caco-2 cells were raised on semipermeable membranes under conditions that model different regions of the crypt and villus. Gln availability was controlled by addition to the medium and treatment with methionine sulfoximine to inhibit Gln synthetase (GS). Barrier function was assayed by measuring transepithelial electrical resistance and fluxes of [(14)C]mannitol and fluorescein isothiocyanate-dextran. The barrier function of these monolayers was found to require the Gln provided either in the medium at the apical or basal surface or via GS. However, the barrier was no more sensitive to Gln deprivation than it was to accumulation or maintenance of total protein. These results suggest that the in vivo dependence of the gut mucosal barrier on Gln likely involves roles separate from maintenance of the epithelial barrier per se.     

甲硝唑葡萄糖注射液细菌内毒素检查法的研究

目的;以细菌内毒素检查法对甲硝唑葡萄糖注射液进行试验研究。方法;采用抑制或增强试验,并将细菌内毒素检查法与家兔法检测结果作对比。结果：该注射液经一定稀释后对测定无干扰。结论：细菌内毒素检查法适用于检测该注射液。     

Poor correlation between pulmonary arterial wedge pressure and left ventricular end-diastolic volume after coronary artery bypass graft surgery

The authors studied 12 surgical patients in the intensive care unit post coronary artery bypass graft surgery and ten nonsurgical patients in the coronary care unit with chronic heart failure to determine the usefulness of the pulmonary arterial wedge pressure as an indicator of left ventricular preload. Left ventricular end diastolic volume was derived from concomitant determination of ejection fraction (gated blood pool scintigraphy) and stroke volume (determined from thermodilution cardiac output). In the nonsurgical patients, there was a significant correlation between changes in pulmonary arterial wedge pressure and left ventricular end-diastolic volume (P less than 0.05, r = 0.57). In the 12 patients studied during the first few hours after surgery, there was a poor correlation between changes in pulmonary wedge pressure (range = 4-32 mmHg) and left ventricular end-diastolic volume (range = 25-119 ml/m2), and a poor correlation between pulmonary arterial wedge pressures and stroke work index. In contrast, there was a good correlation between left ventricular end-diastolic volume and stroke work index. The poor correlation between the pulmonary arterial wedge pressure and left ventricular end-diastolic volume was not explained by changes in systemic or pulmonary vascular resistance. The altered ventricular pressure-volume relationship may reflect acute changes in ventricular compliance in the first few hours following coronary artery bypass graft surgery. While measurement of pulmonary arterial wedge pressure remains valuable in clinical management to avoid pulmonary edema, it cannot reliably be used as an index of left ventricular preload while attempting to optimize stroke volume in patients immediately following coronary artery bypass graft surgery.