Search PubMed⌕ Search

Biomedical subjects

M Rubin

Publications and source records attributed to M Rubin.

At least 91 records · Page 5Linked to original sources
PubMed1996

The effects of dietary phospholipids enriched with phosphatidylethanolamine on bile and red cell membrane lipids in humans.

The role of phospholipids in biliary cholesterol solubilization and crystallization has only recently begun to be appreciated. Phospholipid vesicles are believed to be the metastable carrier from which cholesterol nucleates. Cholesterol crystallization is influenced by the phospholipid species in bile. Feeding rats and hamsters with diets enriched in phospholipids or their precursors, especially ethanolamine, resulted in reduced cholesterol saturation of bile. Although whole phospholipids are normal dietary constituents, the effects and safety of phospholipid components have not been tested in humans. In the present study, we have evaluated the effects of a dietary phospholipid mixture, enriched with phosphatidylethanolamine, on human bile and red blood cell membrane lipid composition. Five ambulatory volunteers having a chronic indwelling T-tube, with an intact enterohepatic circulation, were investigated. Thirty-six grams of phospholipids (54% phosphatidylethanolamine, 54% linoleyl acyl chains) were added to their daily diet for fourteen days. Biliary nucleation time, cholesterol carriers, as well as plasma, red blood cell membrane, and bile lipid compositions, were monitored. Following phospholipid supplementation, the proportion of linoleyl chains (18:2) in biliary phospholipids increased significantly from 31.1 +/- 1.2 to 37.7 +/- 5.3%, while that of oleyl chains (18:1) decreased from 11.4 +/- 1.6 to 9.6 +/- 1.1%. These changes were accompanied by an increase of linoleate and its metabolite, arachidonate, in red cell membranes. Phospholipid feeding did not cause any side effects, and no significant changes in biliary nucleation time, cholesterol, phospholipid, or bile salt concentrations, or in the distribution of cholesterol within micelles or vesicles. We conclude that phospholipid feeding is safe, and can be effective as a vehicle for lecithin fatty acyl chain modulation of bile and lipid membranes. These findings may provide a basis for a controlled modulation of biliary phospholipids to increase cholesterol solubility in bile.

Adult↗
PubMed1996

Lamivudine in children with human immunodeficiency virus infection: a phase I/II study. The National Cancer Institute Pediatric Branch-Human Immunodeficiency Virus Working Group.

The safety, tolerability, pharmacokinetic profile, and preliminary activity of lamivudine (2'-deoxy-3'-thiacytidine), a novel cytidine nucleoside analogue with antiretroviral activity, in human immunodeficiency virus (HIV)-infected children beyond the neonatal period were studied. Ninety children received dosages of 1-20 mg/kg/day. Pharmacokinetic evaluation demonstrated serum and cerebrospinal fluid concentrations that increased proportionally to dose. As of January 1994, 11 children had been withdrawn from study for disease progression and 10 because of possible lamivudine-related toxicity, and 6 had died. CD4 and CD8 cell counts remained stable over 24 weeks in therapy-naive children and decrease slightly in previously treated children. Quantitative immune complex-dissociated p24 antigen and HIV RNA were decreased significantly at 12 and 24 weeks. In vitro resistance to lamivudine was documented in sequential virus isolates from some patients by 12 weeks. Lamivudine was well-tolerated and exhibited virologic activity in children, although future use in children is likely to be in combination antiretroviral regimens.

Adolescent↗
PubMed1996

HIV-1 RNA levels and the development of clinical disease. North American Lamivudine HIV Working Group.

OBJECTIVE: To assess the prognostic value of HIV RNA levels for predicting clinical disease independently of the CD4 lymphocyte count in patients on antiretroviral therapy. DESIGN: Cohort of HIV-infected patients from two trials of lamivudine therapy. PATIENTS: For 620 patients randomized in the North American NUCA3001 and NUCA3002 trials of lamivudine, HIV RNA levels were measured (median, seven measures per patient) and CD4 counts were assessed at a central laboratory (median, 13 counts per patient). Patients were in the 1993 Centers for Disease Control and Prevention (CDC) stages A (n = 439), B (n = 135) or C (n = 46) at baseline. OUTCOME MEASURES: For patients who were in CDC stage A at baseline we considered the ability of HIV RNA levels and CD4 counts to predict the development of CDC stage B or C disease. A Cox proportional hazards model was used. In a second analysis, patients who were AIDS-free at baseline were considered, and the endpoint was AIDS (CDC stage C). RESULTS: Patients' initial CD4 counts ranged (5-95% centiles) from 104 to 529 x 10(6)/l (median, 274 x 10(6)/l) and HIV RNA levels from 1900 to 339680 copies/ml (median, 44240 copies/ml). For the first analysis, with CDC stage B or C disease as endpoint, both the most recent HIV RNA level and CD4 count predicted the development of clinical disease [relative hazard (RH) for HIV RNA, 1.96 per 10-fold difference in HIV RNA; 95% confidence interval (CI), 1.41-2.73; P = 0.0001; and RH for CD4 count, 1.82 per twofold difference in CD4 count; 95% CI, 1.27-2.56; P = 0.0009]. When both HIV RNA and CD4 count were included in a multiple regression model, both markers provided information additional to that given by the other (RH for HIV RNA, 1.75; 95% CI, 1.23-2.50; P = 0.002; and RH for CD4 count, 1.40; 95% CI, 0.95-2.07; P = 0.09). In the second analysis, with AIDS as endpoint, both HIV RNA level (P = 0.02) and CD4 count (P = 0.004) were independently associated with clinical progression. These results were essentially unchanged after adjustment for treatment arm (zidovudine/lamivudine versus control arms). CONCLUSION: The HIV RNA level shows ability to predict the development of clinical disease and may thus be of importance in addition to the CD4 count in patient monitoring.

Adult↗
PubMed1996

Drug resistance and virologic response in NUCA 3001, a randomized trial of lamivudine (3TC) versus zidovudine (ZDV) versus ZDV plus 3TC in previously untreated patients.

OBJECTIVE: To study the effect of HIV-1 resistance to lamivudine (3TC) and zidovudine (ZDV), and syncytium-inducing (SI) phenotype on virologic response to treatment with ZDV, 3TC, or ZDV plus 3TC in previously untreated individuals with HIV-1 infection. DESIGN: A prospective virologic substudy of GlaxoWellcome protocol NUCA 3001. METHODS: HIV-1 isolates obtained at study entry and at week 12 were expanded in peripheral blood mononuclear cell (PBMC) culture, titered, and assayed for phenotypic and genotypic evidence of resistance to ZDV and 3TC, and for syncytium formation on MT-2 cells. RESULTS: Phenotypic and genotypic resistance to 3TC was detected in the majority of HIV-1 isolates from patients who received 3TC alone or in combination with ZDV. Despite showing 3TC resistance, subjects who received 3TC in combination with ZDV had significantly greater decreases in plasma HIV-1 RNA levels compared with those who received ZDV alone. Occurrence of the K7OR ZDV resistance mutation was significantly reduced in patients who received the 3TC/ZDV combination as compared with patients on ZDV monotherapy. Plasma HIV-1 RNA returned to near-baseline levels more quickly in patients with SI isolates at study entry. CONCLUSIONS: Despite the rapid emergence of 3TC resistance, combination therapy with 3TC plus ZDV resulted in greater reduction in plasma HIV-1 RNA levels over 24 weeks as compared to ZDV monotherapy. Prevention of ZDV resistance may contribute to the sustained activity of the combination therapy.

Adult↗
PubMed1996

Motor neuropathy due to docetaxel and paclitaxel.

Paclitaxel and docetaxel are novel chemotherapeutic agents that promote the polymerization and inhibit the depolymerization of microtubules. Sensory neuropathy is common with these agents, particularly paclitaxel. We evaluated 64 patients treated with these drugs; 54 were followed prospectively. Eleven (17%, including six of the 54 prospectively followed patients) developed muscle weakness that was predominantly proximal. The weakness was idiosyncratic, occurring at any stage of treatment, had a variable course, and was reversible upon cessation of drug. All patients developed symptoms or signs of taxane-induced sensory neuropathy. Weakness was likely neuropathic in origin; electrodiagnostic studies suggested a distal axonopathy in some patients and proximal denervation (anterior horn cell or nerve root) in other.

Adult↗
PubMed1996

Response of small cell carcinoma of pancreas to a small cell lung cancer regimen: a case report.

Small cell carcinoma of the pancreas is a very rare malignancy with 18 cases reported in the literature, of which only 3 were treated with chemotherapy. A 52-year-old man was diagnosed with small cell carcinoma originating in the head of the pancreas and invading the duodenum. He was treated with a similar approach as for localized small cell lung cancer, with six cycles of combination chemotherapy and local radiotherapy, and went into complete remission. After 3 months, he developed liver metastases along with an enlarged left supraclavicular lymph node. He was treated with two cycles of CVA, but developed lung metastases and was treated with ifosfamide/mesna. However, his overall condition deteriorated and hospice care was instituted until the patient's demise. The patient survived 14 months following diagnosis, significantly longer than the 15 reported patients with small cell pancreatic carcinomas not treated with chemotherapy. Combination chemotherapy and radiation therapy as it is utilized for small cell lung cancer appear to be beneficial for small cell carcinoma of the pancreas.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Does lipid infusion affect bile composition in humans?

A prospective study was performed to investigate the effect of short-term lipid infusion on bile composition and its lithogenicity in humans. The study group comprised 44 patients scheduled for laparotomy. The patients were hospitalized 48 h prior to elective surgery and randomized to be infused with a lipid emulsion of either long chain triglycerides (LCT) or a mixture of medium and long chain triglycerides (MCT/LCT) for 6 h of each 24 h, or with glucose-saline. Bile samples were obtained by puncture of the gallbladder during operation. In non-gallstone patients, both lipids caused an elevation of biliary cholesterol and phospholipids, but this effect was more pronounced and significant (P <0.001) only with the mixture of MCT/LCT emulsion. The fatty acid composition of biliary phospholipids was not affected by either lipid infusion. The Cholesterol Saturation Index increased significantly (P <0.005) with the MCT/LCT emulsion and there was insignificant shortening in the nucleation time. In contrast to patients with cholelithiasis, no effects could be demonstrated on gallbladder bile composition, cholesterol saturation index, nucleation time, or fatty acid composition of phospholipids. The effects of both lipid emulsions on plasma lipids and lipoproteins were similar in all groups. Our results indicate that lipid emulsions containing MCT/LCT induce lithogenic changes in the composition of human bile. We propose that the lack of effect of lipid infusion on bile composition in patients with cholelithiasis may be due to precipitation of excess cholesterol in the gallbladder of cholesterol gallstone patients whose bile is already saturated. These findings imply that patients with cholesterol gallstones cannot be grouped with non-gallstone patients in studies of alterations of bile composition.

Bile↗
PubMed1995

A preliminary trial of lamivudine for chronic hepatitis B infection.

BACKGROUND: Better treatments for chronic hepatitis B are needed. Lamivudine, the (-)enantiomer of 3'-thiacytidine, is a potent inhibitor of hepatitis B virus (HBV). METHODS: In a double-blind trial, we randomly assigned 32 patients with chronic hepatitis B (including 17 who had no response to earlier treatment with interferon) to receive 25, 100, or 300 mg of oral lamivudine daily for 12 weeks. The patients were then followed for 24 additional weeks. All the patients had hepatitis B antigen in serum. RESULTS: Levels of HBV DNA became undetectable (< or = 1.5 pg per milliliter) in 70 percent of the patients who received the 25-mg dose of lamivudine and 100 percent of those treated with the 100-mg or 300-mg dose. In most patients, HBV DNA reappeared after therapy was completed; however, six patients (19 percent), including five who had not responded to interferon, had sustained suppression of HBV DNA accompanied by normalization of alanine aminotransferase levels. Hepatitis B e antigen disappeared in four of these six patients (12 percent), three of whom had had no response to interferon. Levels of HBV DNA fell in all patients, including those who had had high levels at base line or normal alanine aminotransferase levels at base line, but sustained responses were more likely in patients with initially low HBV DNA levels and high alanine aminotransferase levels. During and after therapy, alanine aminotransferase levels at least doubled in five patients (50 percent) given the 25-mg dose and eight patients (36 percent) given the 100-mg or 300-mg dose. Minor adverse events occurred that were not related to the dose, as did transient, asymptomatic elevations of amylase, lipase, and creatine kinase levels. CONCLUSIONS: In a preliminary trial, 12 weeks of lamivudine therapy was well tolerated, and daily doses of 100 mg and 300 mg reduced HBV DNA to undetectable levels.

Adolescent↗
PubMed1995

Treatment with lamivudine, zidovudine, or both in HIV-positive patients with 200 to 500 CD4+ cells per cubic millimeter. North American HIV Working Party.

BACKGROUND: The reverse-transcriptase inhibitor lamivudine has in vitro synergy with zidovudine against the human immunodeficiency virus (HIV). We studied the activity and safety of lamivudine plus zidovudine as compared with either drug alone as treatment for patients with HIV infection, most of whom had not previously received zidovudine. METHODS: Three hundred sixty-six patients with 200 to 500 CD4+ cells per cubic millimeter who had received zidovudine for four weeks or less were randomly assigned to treatment with one of four regimens: 300 mg of lamivudine every 12 hours; 200 mg of zidovudine every 8 hours; 150 mg of lamivudine every 12 hours plus zidovudine; or 300 mg of lamivudine every 12 hours plus zidovudine. The study was double-blind and lasted 24 weeks, with an extension phase for another 28 weeks. RESULTS: Over the 24-week period, the low-dose and high-dose regimens combining lamivudine and zidovudine were associated with greater increases in the CD4+ cell count (P = 0.002 and P = 0.015, respectively) and the percentage of CD4+ cells (P < 0.001 for both) and with greater decreases in plasma levels of HIV-1 RNA (P < 0.001 for both) than was treatment with zidovudine alone. Combination therapy was also more effective than lamivudine alone in lowering plasma HIV-1 RNA levels and increasing the percentage of CD4+ cells (P < 0.001 for all comparisons), and these advantages persisted through 52 weeks. Adverse events were no more frequent with combination therapy than with zidovudine alone. CONCLUSIONS: In HIV-infected patients with little or no prior antiretroviral therapy, treatment with a combination of lamivudine and zidovudine is well tolerated over a one-year period and produces more improvement in immunologic and virologic measures than does treatment with either agent alone.

Adult↗
PubMed1995

Chelation therapy.

Explore the source record for details and available documents.

Chelation Therapy↗
PubMed1995

Importance of TNF production for the curative effectiveness of low dose melphalan therapy for mice bearing a large MOPC-315 tumor.

We have previously shown the importance of the acquisition of CD8+ T cell-dependent tumor-eradicating immunity for the curative effectiveness of low dose melphalan (L-PAM, L-phenylalanine mustard) for mice bearing a large MOPC-315 tumor. Here we show the importance of TNF production for the curative effectiveness of low dose L-PAM for such tumor-bearing mice. Studies regarding the mechanism(s) through which TNF exerts its antitumor effects in L-PAM-treated MOPC-315 tumor-bearing mice (L-PAM TuB mice) revealed that MOPC-315 tumor cells are not sensitive to the cytotoxic effects of TNF either before or after the chemotherapy. However, TNF is essential for the in vitro generation of potent CTL activity by CD8+ T cells from L-PAM TuB mice. Moreover, addition of exogenous TNF to in vitro stimulation cultures of spleen cells from untreated mice bearing a large MOPC-315 tumor resulted in the generation of a greatly enhanced CTL activity against MOPC-315-associated Ags. Finally, we have previously shown that TCR V beta 8+/CD8+ T cells are involved in the curative effectiveness of low dose L-PAM for mice bearing a large MOPC-315 tumor. Here we show that TNF is important for the ability of MOPC-315-specific V beta 8+/CD8+ T cell lines from L-PAM TuB mice to bring about tumor eradication upon adoptive transfer into tumor-bearing mice. Taken together, these studies illustrate that low dose L-PAM mediates its therapeutic effectiveness for mice bearing a large MOPC-315 tumor, at least in part, via TNF production (e.g., by V beta 8+/CD8+ T cells), which in turn promotes the generation of anti-MOPC-315 CTL activity.

Animals↗
PubMed1995

Renal artery stenosis presenting as crescendo angina pectoris.

The coexistence of different clinical syndromes due to atherosclerosis in different organs is not rare and emphasizes the diffuse nature of this vascular process. Although renovascular disease may cause hypertension and/or renal insufficiency, it may also occur in the absence of the usual clinical markers that suggest renovascular hypertension. We report a patient with stable coronary anatomy who presented with crescendo angina pectoris. Diagnosis of renovascular hypertension was made by screening renal angiography at the time of the cardiac catheterization. Renal artery stenting resulted in stabilization of the coronary syndrome and obviated the need for further coronary intervention. To our knowledge, this is the first case of renovascular hypertension precipitating an unstable coronary syndrome in a patient with documented stable coronary anatomy. Review of the literature supports that patients undergoing cardiac catheterization are a high risk population for renovascular disease, particularly in the presence of other predictive factors such as documented coronary artery disease, older age, female gender, congestive heart failure, peripheral vascular disease, renal insufficiency, and smoking. Firm recommendations for routine screening renal angiography in patients undergoing peripheral or coronary angiography will need further studies.

Aged↗
PubMed1995

Morbidity of subtotal colectomy in patients with severe ulcerative colitis unresponsive to cyclosporin.

PURPOSE: The aim of this study was to document the morbidity of urgent subtotal colectomy and ileostomy in patients with severe ulcerative colitis who failed cyclosporin treatment. METHODS: We reviewed the charts of patients with severe ulcerative colitis who did not respond to cyclosporin treatment and underwent urgent subtotal colectomy and Brooke ileostomy at two inflammatory bowel disease centers over the 12-month period ending April 1994. RESULTS: Fourteen patients (6 males; mean age, 34 years) required an urgent subtotal colectomy and Brooke ileostomy after failing treatment with cyclosporin. There were no deaths. Eight patients (57 percent) developed post-operative complications, which included ileus (3), deep vein thrombosis (2), wound infection (2), and partial dehiscence of rectal stump (1). Mean length of postoperative hospital stay was 8.8 days. CONCLUSIONS: These initial data suggest that cyclosporin treatment may not influence the safety of urgent surgical treatment in severe ulcerative colitis.

Adolescent↗
PubMed1995

Prospective analysis of perioperative morbidity in one hundred consecutive colectomies for ulcerative colitis.

BACKGROUND: This study was undertaken to evaluate prospectively the indications for surgical treatment and perioperative morbidity for patients with idiopathic ulcerative colitis (UC). METHODS: Between January 1985 and August 1994, 145 patients were referred to the senior author (F.M.) for treatment of UC. Data were prospectively collected. One hundred patients have completed all stages of their surgical treatment and have been followed up for at least 1 year. These 100 patients form the basis of this study. RESULTS: Thirty patients underwent a proctocolectomy with end-ileostomy in one (25) or two (5) stages. Seventy patients underwent a restorative proctocolectomy with ileal J-pouch anal anastomosis in either one (2), two (37), or three stages (31). In total 100 patients underwent 204 procedures. Failure of medical treatment was by far the most common indication. The initial colectomy was performed electively in 61 patients and urgently in the remaining 39. The rate of perioperative complications for elective and urgent colectomy was 26% and 44%, respectively (p < 0.05). CONCLUSIONS: The overall perioperative morbidity rate remains high and almost doubles for urgent cases. Reducing the need for urgent procedures by earlier elective colectomy may allow for a reduction in perioperative morbidity.

Colectomy↗
PubMed1995

Are bilirubin and plasma lipid profiles of premature infants dependent on the lipid emulsion infused?

The effect of a lipid emulsion containing long-chain triglycerides (LCT) and supplemented with L-carnitine on plasma lipids and bilirubin in premature neonates on total parenteral nutrition was compared to that of lipid emulsions containing either LCT or a mixture of LCT and medium-chain triglycerides (MCT). In a double-blind randomized study 49 premature neonates received one of the three fat emulsions, given intravenously, over 16-20 h daily for 6 days. Plasma carnitine levels increased significantly in the supplemented group only; the addition of carnitine did not seem to affect any of the parameters studied. Mean plasma triglycerides rose by 193 and 199% in the carnitine-supplemented and the LCT groups, respectively, and by 314% in the MCT/LCT group. On the sixth day of the study free fatty acids were significantly higher in the MCT/LCT group than in the other two groups. Plasma phospholipids and free cholesterol increased (p < 0.05) progressively in all groups and were correlated (r = 0.74, p < 0.001). At the end of the 6-day study all groups showed a similar decline in free and total bilirubin levels despite the significant increase in plasma lipids and free fatty acids resulting from the stepwise increase in lipid load. No correlation was found between free fatty acids and free bilirubin. Since hyperbilirubinemia and hypertriglyceridemia appear to be clinically independent factors, the infusion of lipids should not be withheld from jaundiced infants on total parenteral nutrition.

Bilirubin↗
PubMed1995

Antipyrine disposition in the dehydrated camel.

In the present study the effects of water deprivation in the camel (Camelus dromedarius) on the pharmacokinetic profile of antipyrine were assessed. A cross-over design was used. The pharmacokinetics of antipyrine in adult and young camels were compared. Antipyrine was administered intravenously to young and adult female camels when water was available ad libitum and to the adult camels after 14 days of dehydration. The elimination half-life of antipyrine in watered adult camels was 136.5 +/- 16.7 min. The half-life of elimination and the mean residence time of antipyrine were significantly prolonged following dehydration. The observed effects of water deprivation were not a function of age, as the pharmacokinetic profile of antipyrine in young camels was similar to that of the adults, but more likely due to the changes in oxidative metabolic capacity of the liver as a result of a reduced general metabolism. The results of the present study also show that the intrinsic clearance of antipyrine is proportional to the camel's body weight, as previously shown for other mammalian species.

Aging↗
PubMed1995

Monotherapy for fever and neutropenia in cancer patients: a randomized comparison of ceftazidime versus imipenem.

PURPOSE: To compare the efficacy of ceftazidime and imipenem monotherapy for fever and neutropenia, and to determine whether fewer antimicrobial modifications (additions or changes) are required by the broader-spectrum agent, imipenem. PATIENTS AND METHODS: Adult and pediatric patients undergoing chemotherapy for solid tumors, leukemias, or lymphomas were randomized to receive open-label ceftazidime or imipenem on presentation with fever and neutropenia. Success with or without modifications of the initial antibiotic was defined as survival through neutropenia; failure was death due to infection. Comparisons were based on numbers of modifications made to each monotherapy during the course of neutropenia, in patients stratified as having unexplained fever or a documented infection. RESULTS: Among 204 ceftazidime and 195 imipenem recipients, the overall success rate with or without modification was more than 98%, regardless of initial antibiotic regimen. Modifications occurred in half of all episodes, primarily in patients with documented infections on either monotherapy. Antianaerobic agents were more frequently added to ceftazidime (P < .001), but addition of other antibiotics, including vancomycin and aminoglycosides, was similar between the two monotherapy groups. Imipenem therapy was associated with significantly greater toxicity, manifested by Clostridium difficile-associated diarrhea and by nausea and vomiting, which required discontinuation of imipenem in 10% of recipients. CONCLUSION: Ceftazidime and imipenem are both effective in the management of fever and chemotherapy-related neutropenia, provided that modifications are made in response to clinical and microbiologic data that emerge during the course of neutropenia. Imipenem, despite its broader antimicrobial spectrum, does not significantly decrease the overall need for antibiotic modifications and is more often complicated by gastrointestinal toxicity.

Acyclovir↗