Development of molecular probes for the identification of extra interaction sites in the mid-gorge and peripheral sites of butyrylcholinesterase (BuChE). Rational design of novel, selective, and highly potent BuChE inhibitors

Tacrine heterobivalent ligands were designed as novel and reversible inhibitors of cholinesterases. On the basis of the investigation of the active site gorge topology of butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE) and by using flexible docking procedures, molecular modeling studies formulated the hypothesis of extra interaction sites in the active gorge of hBuChE, namely, a mid-gorge interaction site and a peripheral interaction site. The design strategy led to novel BuChE inhibitors, balancing potency and selectivity. Among the compounds identified, the heterobivalent ligand 4m, containing an amide nitrogen and a sulfur atom at the 8-membered tether level, is one of the most potent and selective BuChE inhibitors described to date. The novel inhibitors, bearing postulated key features, validated the hypothesis of the presence of extra interaction sites within the hBuChE active site gorge.     

Risk of Mortality during Four Years after Substance Detoxification in Urban Adults

The objective of this analysis was to assess the mortality rate and risk factors in adults, with substance dependence, who are not receiving primary medical care (PC). Date and cause of death were identified using the National Death Index data and death certificates for 470 adults without PC over a period of almost 4 years after detailed clinical assessment after detoxification. Factors associated with risk of mortality were determined using stepwise Cox proportional hazards models. Subjects were 76% male, 47% homeless, and 47% with chronic medical illness; 40% reported alcohol, 27% heroin, and 33% cocaine as substance of choice. Median age was 35. During a period of up to 4 years, 27 (6%) subjects died. Median age at death was 39. Causes included: poisoning by any substance (40.9% of deaths), trauma (13%), cardiovascular disease (13.6%), and exposure to cold (9.1%). The age adjusted mortality rate was 4.4 times that of the general population in the same city. Among these individuals without PC in a detoxification unit, risk factors associated with death were the following: drug of choice [heroin: hazard ratio (HR) 6.9 (95% confidence interval (CI) 1.6–31.1]; alcohol: HR 3.7 (95% CI 0.79–16.9) compared to cocaine); past suicide attempt (HR 2.1, 95% CI 0.96–4.5); persistent homelessness (HR 2.4, 95% CI 1.1–5.3); and history of any chronic medical illness (HR 2.1, 95% CI 0.93–4.7). Receipt of primary care was not significantly associated with death (HR 0.85, 95% CI 0.34–2.1). Risk of mortality is high in patients with addictions and risk factors identifiable when these patients seek help from the health care system (i.e., for detoxification) may help identify those at highest risk for whom interventions could be targeted. Saitz, Cheng, Richardson, and Samet are with the Clinical Addiction Research and Education Unit, Department of Medicine, Boston Medical Center, Boston, MA, USA; Saitz, Gaeta, Cheng, Richardson, and Samet are with the Section of General Internal Medicine, Department of Medicine, Boston Medical Center, Boston, MA, USA; Saitz and Richardson are with the Youth Alcohol Prevention Center, Boston University School of Public Health, Boston, MA, USA; Gaeta is with the Boston Health Care for the Homeless Program, Boston, MA, USA; Cheng is with the Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA; Larson is with the New England Research Institutes, Watertown, MA, USA; Samet is with the Department of Social & Behavioral Sciences, Boston University School of Public Health, Boston, MA, USA.     

Aneurysms of the abdominal aorta in elderly patients]

Aneurysms of the abdominal aorta are often diagnosed in the over-75s. Although for many Authors the presence of risk factors such as cardiopathies, cerebrovascular problems, renal or respiratory insufficiency, which are clearly more frequent in elderly patients, represent a contraindication to the intervention of choice, personal experience has shown that surgery remains the best solution. In fact, in a group of patients operated on for aneurysm of the abdominal aorta in a heart, no significant differences in age-related mortality were observed. Surgery therefore remains the treatment of choice in the elderly too for it must also be remembered that the natural history of the disease has shown that, in a comparatively short time, the aneurysm ruptures and operating mortality is markedly higher.     

Decellularized dermis in combination with cultivated keratinocytes in a short- and long-term animal experimental investigation

Decellularized human dermis as a potentially ideal scaffold for dermal substitution in severe burns was examined in a two‐staged animal experiment. In an initial step, an in vitro generated composite graft consisting of human keratinocytes and decellularized dermis (AlloDerm®) was transplanted onto nude mice in a short‐term trial (n = 20, 14 days). Subsequently, a combined one‐step grafting of full thickness wounds with both decellularized dermis (in part preincubated with fibroblasts) and cultivated autologous keratinocytes as a cell suspension in fibrin glue was done in a long‐term porcine animal model (n = 10, 6 months). In both series, macroscopic wound healing was evaluated by planimetry. Histological investigations included morphological as well as immunohistochemical parameters. The short‐term study showed both successful integration of the composite grafts and reduction of wound contraction compared with the control group (epithelial grafts). The long‐term porcine study displayed reduced myofibroblast formation and contraction in the wounds that had been treated with fibroblast‐preincubated dermis. After 4 weeks, a decline of the structural integrity of the dermal matrix could be noticed. The utility of decellularized dermis as template for both dermal reconstitution and keratinocyte delivery vehicle was shown. The closure of full thickness wounds by a single‐step combination of an autologous keratinocyte fibrin sealant suspension and acellular dermis in a pig animal model could be shown. Incorporation of fibroblasts led to reduced wound contraction but could not prevent the loss of dermal integrity. The engineered ‘skin’ remained viable and stable over a period of 6 months.     

Cefodizime (HR221) versus norfloxacin for treatment of urinary tract infections

Cefodizime is a stable new beta-lactamase cephalosporin chemically related to cefotaxime and with a long half-life. Its clinical efficacy and tolerability were compared with those of norfloxacin in patients with intercurrent urinary tract infections plus chronic liver diseases. Cefodizime (2 g, once a day, i.v.) and norfloxacin (400 mg, twice a day, p.o.) were randomly given to two groups of 20 patients each with urinary tract infections caused by organisms sensitive in vitro to these drugs. Cultures of midstream bladder urine, urinalysis and blood biochemical tests were performed before and after each antibiotic treatment. Clinical resolution was observed in 100% of the patients at the end of the treatments, but bacteriological eradication was obtained in 90% of the patients treated with cefodizime and 85% of those treated with norfloxacin, because of the development in five patients of asymptomatic bacteriuria (superinfections).     

Blood group A immunodeterminants on human red cells differ in biologic activity and sensitivity to alpha-N-acetylgalactosaminidase

BACKGROUND: Epitopes of blood group A antigen can be enzymatically cleaved from red cells (RBCs), but the extent of cleavage required for normal survival in allogeneic blood transfusion recipients is unknown. Therefore, the cleavage rates were studied for A antigen epitope binding of 1) complement-activating anti-A, 2) Dolichos biflorus anti- A, lectin, and 3) hemagglutinating anti-A during incubation with a purified alpha-N-acetylgalactosaminidase, E.C. 3.2.1.49 (alpha- GalNAc'ase). STUDY DESIGN AND METHODS: Suspensions of group A RBCs were incubated with alpha-GalNAc'ase. Cells were removed at intervals, washed, and tested for loss of binding by monoclonal, polyclonal, and complement-activating anti-A, D. biflorus anti-A1 lectin, and Ulex europaeus anti-H lectin. RESULTS: A epitopes binding D. biflorus lectin were highly susceptible to alpha-GalNAc'ase; simultaneously with their loss, binding with U. europaeus lectin emerged. Loss of complement- mediated hemolysis was slower. A epitopes binding hemagglutinating anti- A were most resistant. Cleavage of A epitopes from membrane glycosphingolipids with short oligosaccharide chains was similarly resistant. Rates of cleavage from A1 and A2 RBCs were similar. CONCLUSION: RBC epitopes of blood group A differ in susceptibility to cleavage and biologic reactivity, which suggests that subsets mediating important biologic functions exist on functionally and topographically distinct membrane glycoconjugates.     

Effect of 50 Milliliters of 50% Dextrose in Water Administration on the Blood Sugar of Euglycemic Volunteers

Abstract. Objective : To evaluate the effect of administration of 1 ampule of 50% dextrose in water solution (D₅₀W) on serum glucose levels in healthy adult volunteers, the authors set out to determine whether a pre-D₆₀W serum glucose level can be predicted from the ED sample. Methods : This was a prospective, interventional study conducted from the ED of an urban, university-affiliated hospital. All subjects were healthy employee volunteers between 25 and 40 years of age. Baseline serum glucose levels were determined and all subjects were given an IV bolus of 25 grams of 50% dextrose solution. The main outcome measures were post-D₅₀W serum glucose levels (observed) at 5 predetermined time intervals (5 min, 15 min, 30 min, 1 hr, and 2 hr). An expected change in serum glucose was calculated using the volume of distribution formula for glucose. Results : Twenty-five volunteers (17 males and 8 females) participated in the study. The mean baseline serum glucose was 82.3 ± 13.5 mg/dL. The mean post-infusion levels were: 244.4 ± 44.6 mg/dL (5 min), 145.8 ± 52.3 mg/dL (15 min), 88.1 ± 28.8 mg/dL (30 min), 77.6 ± 13.6 mg/dL (60 min), and 83.2 ± 11.4 mg/dL (120 min). Using a mixed-effect regression model, statistically significant increases in serum glucose levels were found at 5 minutes (p < 0.001) and 15 minutes (p < 00001) following administration of D₅₀W. There was a return to baseline serum glucose by 30 minutes. The expected change based on the volume of distribution formula (53.7 ± 34.9) did not correlate with the observed changes at any measured time interval. Conclusion : Without pre-intervention blood drawing by emergency medical services, it is not possible to accurately predict pre-D₅₀W serum glucose levels based on post-D₅₀W glucose levels. The diagnosis of hypoglycemia as the etiology of altered mental status must therefore remain a diagnosis of exclusion. In addition, the return of serum glucose to baseline after 30 minutes suggests the duration of the effect of 1 ampule of D₅₀W. Frequent re-evaluation of the serum glucose levels of suspected or proven hypoglycemic patients after administration of D₅₀W should be considered.