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V L Yu

Publications and source records attributed to V L Yu.

At least 73 records · Page 4Linked to original sources
PubMed1996

Candida infection of the arteriovenous fistula used for hemodialysis.

Arteriovenous fistula infection is an exceedingly rare manifestation of Candida infection, with only one case previously reported in the English literature. This report describes three cases of Candida arteriovenous fistula infection seen in a prospective study and reviews the previously reported case. All cases involved the polytetrafluoroethylene graft. The presentations can be either acute or subacute in onset, with drainage at the fistula site as the most common sign. The diagnosis of Candida arteriovenous fistula infection relies on the isolation of the organism from an intraoperative culture of the fistula. Candida was isolated from blood in three of four cases, and wound drainage in two of three cases. Antifungal therapy should be given, but complete removal of the arteriovenous fistula may be necessary for long-term cure.

Aged↗
PubMed1996

Determinants of compliance with antiretroviral therapy in patients with human immunodeficiency virus: prospective assessment with implications for enhancing compliance.

Non-compliance with therapy is a significant problem, particularly when the disease process is chronic and therapeutic regimens are employed for prolonged periods. We assessed the prevalence and variables associated with compliance with antiretroviral therapy in patients with human immunodeficiency virus infection, by means of a longitudinal observational study of 46 patients aged 23 to 68 years, with human immunodeficiency virus infection, followed at the Pittsburgh VA Medical Center. Data on demographics, medical status, physical functioning (Karnofsky performance scores), CD4 lymphocyte count, depression (Beck depression inventory), coping (inventory of coping with illness scale scores), and psychological and emotional stress (profile of mood states scale scores), were prospectively assessed on all patients at baseline and every 6 months. Compliance was assessed at 6 and 12 months: patients taking > or = 80% of antiretroviral therapy were considered compliant. Overall, 63% of patients were compliant with antiretroviral therapy. Age, education, employment, religious support, and perceived quality of life did not correlate with compliance. By univariate analysis, lack of prior intravenous drug use was significantly associated with compliance (p = 0.01). Compliant patients had significantly better adaptive coping (p = 0.03), and less depression (p = 0.04). By multivariate analysis, black race was significantly associated with non-compliance independent of intravenous drug use and educational status. History of prior opportunistic infection (which presumably heightens the perceived severity of illness) (p = 0.02), and lesser psychological disturbance scores (p = 0.02) were associated with compliance. Compliance was observed despite the greater number of prescription medications taken by compliant patients (p = 0.04). At 12 months, Karnofsky scores were better in compliant patients (p = 0.02), although mortality was not different. Besides identifying predictors of compliance, our data suggest that symptoms of depression and psychological stress be sought in patients with non-adherence.

Activities of Daily Living↗
PubMed1996

Candida prosthetic valve endocarditis: prospective study of six cases and review of the literature.

Candida prosthetic valve endocarditis (PVE) is a rare entity; however, its incidence is expected to increase given the recent increase in incidence of nosocomial bloodstream candida infection. This report reviews six cases of candida PVE studied prospectively plus 12 cases previously reported in the literature. Transesophageal echocardiography was more sensitive than transthoracic echocardiography in detecting vegetations. Valvular replacement combined with antifungal therapy has been the standard treatment. However, successful therapy with long-term administration of oral fluconazole has been reported for five patients. The mortality due to candida PVE was high, especially when PVE was complicated by congestive heart failure and persistent fungemia. For uncomplicated PVE, the mortality rate for patients receiving antifungal therapy alone (40%) was no worse than for those receiving combined medical and surgical therapy (33%).

Adult↗
PubMed1996

Low-dose fluconazole as primary prophylaxis for cryptococcal infection in AIDS patients with CD4 cell counts of < or = 100/mm3: demonstration of efficacy in a positive, multicenter trial.

The efficacy of low-dose fluconazole (200 mg orally administered thrice weekly) as primary prophylaxis for cryptococcal infection was prospectively assessed in a multicenter trial involving 218 patients who were infected with human immunodeficiency virus (HIV) and who had CD4 cell counts of < or = 100/mm3. The median CD4 cell count at baseline was 39/mm3, 58% of the patients had an AIDS-defining illness or infection prior to enrollment. Cryptococcal meningitis occurred in 0.4% (1) of the 218 patients. The breakthrough isolate was susceptible to fluconazole, and the fluconazole kinetic study demonstrated adequate drug absorption and serum fluconazole levels; noncompliance could not be excluded in this case. Mucocutaneous and/or esophageal candidiasis developed in 18% (40) of the patients. Noncompliance with fluconazole therapy was the only variable independently associated with breakthrough candidiasis in the study patients (P = .00002). Thus, fluconazole (200 mg thrice weekly) given to HIV-infected patients with CD4 cell counts of < or = 100/mm3 was efficacious as primary prophylaxis for cryptococcosis, with notably lower costs and increased convenience for patients in comparison with daily administration of the drug.

AIDS-Related Opportunistic Infections↗
PubMed1996

Analysis of trends in antimicrobial resistance patterns among clinical isolates of Bacteroides fragilis group species from 1990 to 1994.

Antimicrobial resistance, including plasmid-mediated resistance, among Bacteroides fragilis group species is well documented. A 5-year (1990-1994) prospective, eight-center survey of 3,177 clinical isolates of Bacteroides species was undertaken to review trends in resistance, using the breakpoints for full and intermediate susceptibility established by the National Committee for Clinical Laboratory Standards. No documented resistance to either metronidazole or chloramphenicol was found in this survey. Among B. fragilis isolates virtually no resistance was seen to imipenem, meropenem, ampicillin/sulbactam, piperacillin/tazobactam, or ticarcillin/clavulanate. Significant increases in resistance among B. fragilis isolates to cefotetan, ceftizoxime, and clindamycin (p < .01) were noted. Resistance to cefoxitin remained unchanged. Among the non-fragilis species of the B. fragilis group, there was virtually no resistance to imipenem, meropenem, chloramphenicol, or metronidazole. The three beta-lactamase inhibitors had increasing levels of resistance, although 95%-98% of strains were susceptible (p < .05). There was a significant decline in cefoxitin, cefmetazole, and clindamycin activity over time against these strains (p <.01). There was a significant (P < .001) increase in geometric mean minimum inhibitory concentration for most drugs and species tested from 1990 to 1994. Clusters in the eight institutions could not account for this rise in resistance. This survey demonstrates that rates of resistance of B. fragilis and non-fragilis species of B. fragilis group are increasing.

Bacteroides↗
PubMed1996

Nosocomial Legionnaires' disease caused by Legionella pneumophila serogroup 5: laboratory and epidemiologic implications.

Environmental monitoring and clinical surveillance for Legionella species were done for 12 months as recommended by the Allegheny County Health Department (Pittsburgh). The water system of a hospital was found to be colonized with Legionella pneumophila serogroup 5. Three patients with nosocomial L. pneumophila serogroup 5 disease were subsequently diagnosed after laboratory tests for legionellae were made available for all patients with nosocomial pneumonia. All serogroup 5 isolates from the hospital water matched the 3 patient isolates by pulsed-field gel electrophoresis (PFGE). Furthermore, isolates found in the water supply dating back 10 years showed the same PFGE pattern. In contrast, 12 L. pneumophila serogroup 5 isolates from eight other institutions had different PFGE patterns. Routine environmental cultures were important in stimulating the application of Legionella laboratory testing, which subsequently identified unsuspected patients with nosocomial legionnaires' disease.

Aged↗
PubMed1996

Quantitative comparison in vitro of mutational antibiotic resistance of Enterobacter spp. using a spiral plater.

The presence of spontaneous mutational antibiotic resistance among 18 bacteremic isolates of Enterobacter spp. to cefotaxime, ceftazidime, gentamicin, amikacin, ciprofloxacin, and trimethoprim-sulfamethoxazole was determined quantitatively in vitro using a spiral plater. Each drug was delivered using the device and the agar plates were inoculated in radial streaks. The degree of resistance was estimated by dividing the antimicrobial concentration required to inhibit 90% of the colonies growing in the area beyond the MIC by the MIC itself. The degree of resistance to third-generation cephalosporins and aztreonam was statistically significantly greater than that to co-trimoxazole, imipenem, and ciprofloxacin (P < 0.01); the latter three antibiotics showed virtually no mutational resistance. An intermediate level of resistance was induced by aminoglycosides, and mutational resistance to piperacillin varied between this and the higher levels observed for the cephalosporins. By providing a simple and efficient means of detecting spontaneous mutational resistance, the spiral plater may prove useful in identifying those antimicrobial agents which induce few or no mutants and therefore may be more likely to be successful in treating infections due to Enterobacter spp.

Bacteriological Techniques↗
PubMed1996

A mechanism of rifamycin inhibition and resistance in Pseudomonas aeruginosa.

We sought to study the nature of rifampicin resistance in Pseudomonas aeruginosa. We hypothesized that the rifamycin regions of RNA polymerase are conserved in P. aeruginosa and that rifampicin resistance is mediated by a mutation in the rpoB gene encoding the beta subunit of RNA polymerase. Transcription assays showed that 50 nM of rifampicin inhibited transcription > 99% in a clinical isolate (MIC = 32 mg/L) and only < 40% in the rifampicin resistant mutant (MIC = 1000 mg/L). DNA sequencing revealed that the rifampicin regions are conserved in P. aeruginosa and the rifampicin regions of the rifampicin-resistant strain contained a mutation. Sodium hexametaphosphate lowered rifamycin MIC in a rifamycin-resistant mutant four-fold and in the clinical isolate 32-fold, suggesting that P. aeruginosa has a natural membrane barrier to rifamycins.

Amino Acid Sequence↗
PubMed1996

In vitro activities of two novel oxazolidinones (U100592 and U100766), a new fluoroquinolone (trovafloxacin), and dalfopristin-quinupristin against Staphylococcus aureus and Staphylococcus epidermidis.

Two oxazolidinones (U100592 and U100766), trovafloxacin, and a streptogramin combination (dalfopristin-quinupristin) were highly active in vitro against Staphylococcus aureus and Staphylococcus epidermidis, including methicillin-resistant strains. Trovafloxacin was more active than ciprofloxacin. Time-kill synergy studies demonstrated indifference for the oxazolidinones combined with vancomycin and rifampin against methicillin-resistant staphylococci. Spontaneous resistance was observed with all agents.

Acetamides↗
PubMed1996

Assessment of enzyme immunoassay versus radioimmunoassay for detection of Legionella pneumophila serogroup 1 antigen in frozen urine specimens.

An enzyme immunoassay (EIA) was compared with a radioimmunoassay (RIA) for detection of Legionella pneumophila serogroup 1 antigen in 37 frozen urine samples. Among 18 samples positive by the RIA at the time of collection, 50% (9 of 18) of stored specimens retained positivity when retested by the RIA whereas 78% (14 of 18) of stored specimens retained positivity when retested by the EIA (P < 0.02). A false-negative result occurred after storage for 5 months or less if the original RIA result showed weak positivity.

Humans↗
PubMed1995

Epitope-labeled soluble human interleukin-5 (IL-5) receptors. Affinity cross-link labeling, IL-5 binding, and biological activity.

The human receptor for the potent eosinophilopoietic cytokine interleukin-5 (IL-5) consists of two components: a 60-kDa ligand-binding alpha chain (IL-5 alpha R) and a 130-kDa beta chain (IL-5 beta R). Three ectodomain constructs of the alpha chain (alpha RED) bearing C-terminal epitope tags were engineered and expressed in baculovirus-infected Sf9 cells. Each recombinant alpha chain was secreted into the medium, maximum expression occurring 72 h post-infection. The various soluble alpha chains were shown by affinity cross-link labeling and competition with unlabeled IL-5 to bind recombinant human (rh) 125I-IL-5 specifically with an ED50 of 2-5 nM. The epitope tag provided a simple purification of the receptor from conditioned medium using immunoaffinity chromatography. The purified material had an apparent molecular mass of 43 kDa and was heterogeneously glycosylated. Sedimentation analysis revealed a 1:1 association of the purified epitope-tagged soluble receptor with its ligand, resulting in the formation of a 70-74-kDa complex. Circular dichroism analysis revealed that the soluble alpha chain existed with a significantly ordered structure consisting of 42% beta-sheet and 6% alpha-helix. Such analyses combined with fluorescence spectrometry suggested that ligand-receptor complex formation in solution resulted in minimal conformational changes, consistent with the suggestion that the membrane-associated form of the alpha chain itself has minimal signal transduction capability. Surface plasmon resonance studies of the interaction of the purified alpha RED with immobilized rhIL-5 revealed a specific, competable interaction with a dissociation constant of 9 nM. Preincubation of an IL-5-dependent cell line with the epitope-tagged alpha RED also dose-dependently neutralized rhIL-5-induced proliferation. These data demonstrate that biologically active epitope-tagged recombinant soluble IL-5 receptors are facile to produce in large quantities and may have therapeutic utility in the modulation of IL-5-dependent eosinophilia in man.

Amino Acid Sequence↗
PubMed1995

Molecular cloning and pro-apoptotic activity of ICErelII and ICErelIII, members of the ICE/CED-3 family of cysteine proteases.

Cysteine proteases related to mammalian interleukin-1 beta-converting enzyme (ICE) and the nematode cell death abnormal ced-3 gene product have been implicated in the effector mechanism of apoptotic cell death. Two novel members of this new family of ICE/CED-3-related proteases, designated ICErel-II and ICErel-III, were cloned from human monocytic cells. Both were highly homologous to human ICE (52% identical) and CED-3 (25% identical) and both contained the absolutely conserved pentapeptide sequence Gln-Ala-Cys-Arg-Asp containing the catalytic cysteine residue. Other structural motifs that were comparable with ICE suggest that ICErel-II and ICErel-III are also synthesized as larger proenzymes which are proteolytically processed to form heterodimeric active enzymes. Pro-interleukin-1 beta processing activity could not be detected in cells transfected with ICErel-II or ICErel-III, but pro-domain-less truncated forms of ICErel-II and ICErel-III were capable of effectively inducing fibroblast apoptosis. ICErel-II and ICErel-III may, therefore, participate in proteolytic events culminating in the apoptotic death of human cells.

Amino Acid Sequence↗
PubMed1995

Trimethoprim-sulfamethoxazole for the prevention of spontaneous bacterial peritonitis in cirrhosis: a randomized trial.

OBJECTIVE: To assess the efficacy and safety of trimethoprim-sulfamethoxazole for the prevention of spontaneous bacterial peritonitis in patients with cirrhosis and ascites. DESIGN: A randomized controlled trial. SETTING: University-affiliated Veterans Affairs medical center. PATIENTS: 60 consecutive patients with cirrhosis and ascites. INTERVENTIONS: Consecutive patients were randomly assigned to receive either no prophylaxis or trimethoprim-sulfamethoxazole, one double-strength tablet daily, five times a week (Monday through Friday). Patient entry was stratified by serum bilirubin (> 51 mumol/L [> 3 mg/dL]), ascitic fluid protein (< 1 g/dL), and serum creatinine (> 177 mumol/L [> 2 mg/dL]) levels to ensure that high-risk patients would be similarly distributed in the two groups. The median duration of follow-up for the study patients was 90 days. MAIN OUTCOME MEASURES: Spontaneous bacterial peritonitis or spontaneous bacteremia as defined by objective criteria. RESULTS: Spontaneous bacterial peritonitis or spontaneous bacteremia developed in 27% (8 of 30) of patients who did not receive prophylaxis compared with 3% (1 of 30) of patients receiving trimethoprim-sulfamethoxazole (P = 0.025). Overall, infections developed in 9 of 30 patients (30%) not receiving prophylaxis and in 1 of 30 patients (3%) receiving trimethoprim-sulfamethoxazole (P = 0.012). Death occurred in 6 of 30 patients (20%) who did not receive prophylaxis and in 2 of 30 patients (7%) who received trimethoprim-sulfamethoxazole (P = 0.15). Side effects--particularly, hematologic toxicity--could not be attributed to trimethoprim-sulfamethoxazole in any patient. CONCLUSIONS: Trimethoprim-sulfamethoxazole was efficacious, safe, and cost-effective for the prevention of spontaneous bacterial peritonitis in patients with cirrhosis.

Ascites↗
PubMed1995

Herpes zoster-associated idiopathic thrombocytopenic purpura in a liver transplant recipient: a case report and overview.

Idiopathic (autoimmune) thrombocytopenic purpura has been previously reported as a rare complication in children and in a few adults following chickenpox. We report a case of varicella zoster virus-associated idiopathic thrombocytopenic purpura in an adult liver transplant recipient following dermatomal zoster. Idiopathic thrombocytopenic purpura developed 3 days after the onset of herpes zoster in our patient, with a nadir platelet count of 3000/mm3. The patient was treated with intravenous gamma globulin with recovery of thrombocytopenia after 3 weeks. Transplant clinicians need to be aware that this serious and potentially life-threatening complication may occur with herpes zoster in transplant recipients.

Acyclovir↗
PubMed1995

Invasive gastrointestinal zygomycosis in a liver transplant recipient: case report and review of zygomycosis in solid-organ transplant recipients.

Zygomycosis is a rare but highly invasive fungal infection that occurs in transplant recipients. We report a case of invasive gastrointestinal zygomycosis that occurred in a heavily immunosuppressed liver transplant recipient 5 days after retransplantation and that presented as gastric perforation. Despite aggressive surgical and antifungal therapy, the patient died. We review 46 cases of invasive zygomycosis in solid-organ transplant recipients. The rhinocerebral form of zygomycosis occurred in 57% of cases; the pulmonary, cutaneous, and disseminated forms each occurred in 13%; the renal form occurred in 2%; and the gastrointestinal form occurred in 2%. The infection ensued a median of 2 months after transplantation (range, 5 days to 8 years). Seventy-six percent of the patients had diabetes or had received antirejection therapy, mainly in the form of corticosteroids, before the onset of zygomycotic infection. The mortality for patients who received antifungal therapy and/or who underwent surgery was 50% for those who had rhinocerebral zygomycosis, none for those who had pulmonary and cutaneous zygomycosis, and 100% for those who had disseminated zygomycosis. Knowledge of the diverse clinical manifestations (including gastrointestinal involvement, as is illustrated by our case) and predisposing factors in transplant recipients with zygomycosis can aid in early recognition of this disease in this patient population.

Adult↗