Plasmid-mediated beta-lactamase (TEM-7) involved in resistance to ceftazidime and aztreonam

TEM-7, a novel TEM-type beta-lactamase (pI 5.41) encoded on a plasmid of approximately 85 kilobases, was found in a clinical isolate of Citrobacter freundii. Strains containing this enzyme exhibited decreased susceptibility to ceftazidime (64-fold) and aztreonam (16-fold) but not to other third-generation cephalosporins. Addition of a beta-lactamase inhibitor--clavulanic acid, sulbactam, or YTR 830--restored normal susceptibility to associated compounds such as ampicillin, piperacillin, ceftazidime, and aztreonam. DNA-DNA hybridization of an intragenic probe of TEM-1 occurred with a 19-kilobase EcoRI fragment of the plasmid encoding TEM-7. A TEM-2 derivative, TEM-201, with characteristics similar to those of TEM-7 was selected spontaneously in the presence of ceftazidime in vitro.     

Anatomic correction of transposition of the great arteries associated with ventricular septal defect: midterm results in 50 patients

From May 1977 to August 1982 50 patients who were 1.5 to 44 months old underwent anatomic correction of transposition of the great arteries (TGA) and closure of ventricular septal defect (VSD) at our institution. Thirty-nine patients underwent preliminary pulmonary arterial banding. Hospital mortality was 32%: four patients died as a result of technical problems, seven as a result of associated lesions, three of pulmonary hypertension, and two of left ventricular failure. Three other patients died after the first postoperative month (one of mediastinitis, one at reoperation for a residual VSD, and one of pulmonary hypertension). All 31 survivors are in excellent clinical condition and are in sinus rhythm after a mean follow-up period of 31 +/- 14 months. Twenty-five patients were reinvestigated by echocardiography (M mode and two-dimensional) and/or catheterization. Parameters of left ventricular contractility were within normal limits, but systolic aortic diameter was larger than normal (p less than .01). Seven patients had stenosis of the right ventricular outflow tract and five of these required reoperation. The two persistent problems with the anatomic correction of TGA associated with VSD are a relatively high operative mortality and secondary right outflow tract stenosis. However, use of this procedure results in better left ventricular function and fewer arrhythmias than does use of atrial repair techniques and also results in the use of the anatomically left ventricle as the systemic ventricle.     

Sequential drain amylase to guide drain removal following pancreatectomy

Background

Although used as criterion for early drain removal, postoperative day (POD) 1 drain fluid amylase (DFA) ≤ 5000 U/L has low negative predictive value for clinically relevant postoperative pancreatic fistula (CR-POPF). It was hypothesized that POD3 DFA ≤ 350 could provide further information to guide early drain removal.

Treatment of hepatitis C

Hepatitis C virus infection accounts for 40% of chronic liver disease in the United States and is the most common indication for liver transplantation. Estimates suggest that 4 million people, or 1.8% of the American population, have or have had hepatitis C virus infection. Pegylated interferon and ribavirin are the current standard of care for treatment. Recent studies have suggested that ribavirin dose and duration of therapy may be adjusted based on genotype. The goals of therapy are to slow disease progression, improve hepatic histology, reduce infectivity, and decrease the risk of hepatocellular carcinoma. Sustained virologic response, which generally implies the absence of viremia 6 or more months following completion of therapy, is increasingly being regarded as a cure, with evidence of slowing or even regression of fibrosis on follow-up liver biopsy. Assessment by liver biopsy of disease severity and evaluation of comorbidities and possible contraindications to therapy should be weighed in the decision to begin treatment. Counseling patients regarding transmission, natural history, and drug and alcohol abstinence should also be included in management. Close monitoring should be done during treatment for interferon and ribavirin side effects, including depression, bone marrow suppression, and hemolytic anemia.     

alpha-Defensins can have anti-HIV activity but are not CD8 cell anti-HIV factors

BACKGROUND: CD8 T cells from healthy HIV-infected individuals inhibit HIV replication in infected CD4 T cells by a non-cytotoxic mechanism mediated by a soluble CD8 cell antiviral factor, CAF. Recently, the antimicrobial peptides, alpha-defensins, were reported to constitute CAF. OBJECTIVE: To examine the antiviral activity of alpha-defensins and address their potential role in CD8 cell non-cytotoxic antiviral responses. DESIGN AND METHODS: A purified mixture of human neutrophil proteins (HNP) 1-3 (alpha-defensins) was used to examine the effect of alpha-defensins on HIV virions and on HIV replication in CD4 cells treated prior to or post infection. alpha-Defensin expression was analyzed at the RNA and protein level in CD8 cells as well as in various other cell types. Antibodies to the defensins were tested for their ability to inhibit CAF activity in CD8 cell culture fluids. RESULTS: The alpha-defensins exhibited anti-HIV activity on at least two levels: directly inactivating virus particles; and affecting the ability of target CD4 cells to replicate the virus. However, while we could demonstrate alpha-defensins in neutrophils and monocytes, we found no evidence for the production of these peptides by CD8 T cells. No messenger RNA encoding these proteins was detected in purified CD8 T cells, nor did these cells produce intracellular or extracellular alpha-defensin peptides. Moreover, antibodies specific for human alpha-defensins 1, 2, and 3 did not block the antiviral activity of CAF-active CD8 cell culture fluids. CONCLUSIONS: The alpha-defensins are not produced by CD8 cells but unexpectedly were found to be expressed in monocytes. alpha-Defensins can have anti-HIV activity but are not CD8 cell antiviral factors.     

Lung inflation with direct injection of agarose: a technique for simultaneous molecular and morphometric measurements

The usual methods for preparing lungs for morphologic study involve the instillation of fixatives that modifyproteins and RNA such that the tissue is unsuitable for molecular studies. To develop a technique suitable for molecular studies, pieces of adult rat lungs were infiltrated with agarose, glutaraldehyde, or paraformaldehyde and the consistency of alveolar inflation was compared to lungs inflated with 10% formalin. Only direct injection with 1% agarose resulted in comparable inflation of lung tissue and preserved RNA and protein. Thus, this technique enables simultaneous molecular and morphometric analysis of the lung on small pieces of lung tissue in heterogeneous lung diseases.     

Prevalence and Risk Factors Associated with HIV Infection Among Men Having Sex with Men in Ho Chi Minh City, Vietnam

To learn more about risk behaviors among men who have sex with men (MSM) in Vietnam and their prevalence of HIV, we conducted a study among MSM in Ho Chi Minh City (HCMC) to determine HIV-1 prevalence and behaviors associated with infection. This consisted of formative (35 MSM) and cross-sectional (600 MSM) studies at 72 sites, including 75 transvestites, 55 bisexuals, 10 sex workers, and 460 other MSM. Only 5.3% cohabited with a wife/girlfriend, but 30% reported ever having sex with a female. Prevalence of HIV was 8%, ranging from 33% in sex workers to 7% among transvestites and other MSM. Injecting drugs, selling sex, being 20–40 years old, having less than 6 years of education, and having more than five male anal sex partners in the past month were associated with being HIV-infected. MSM are an HIV bridge group, and should be included in sentinel surveillance. Targeted interventions should be implemented.     

Understanding the tribological impacts of alkali element on lubrication of binary borate melt

Melt lubricants have been regarded as an effective class to deliver lubrication on moving mechanical contacts at extreme temperatures. Among the elementary constituents, alkali elements play a critical role in governing the physical–chemical characteristics of the lubricant despite the obscurity regarding their intrinsic roles on the rubbing interfaces. The present study attempts to unfold the effects of sodium on the tribological responses of mating steel pair under borate melt lubrication. It has been found that the involvement of Na inspires a total reversal in lubricating potentials of the lone B₂O₃ melt manifested by remarkable friction reduction, wear inhibition and prolonged load-bearing capacity. These exceptional performances are attributed to the accretion of nanothin Na layers on the contact interfaces. The interfacial occurrences are interpreted from a physico-chemistry perspective while the influences of surface microstructure are also discussed in detail. Multiple characterizations are employed to thoroughly examine the sliding interfaces in multi-dimensions including Scanning Electron Microscopy (SEM), Scanning Transmission Electron Microscopy (STEM) and Atomic Force Microscopy (AFM). In addition, chemical fingerprints of relevant elements are determined by Energy Dispersive Spectroscopy (EDS) and Electron Loss Energy Spectroscopy (EELS).

The involvement of sodium induces dramatic transformation in lubrication potentials of boron oxide melt.