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Biomedical subjects

D Margolis

Publications and source records attributed to D Margolis.

At least 37 records · Page 2Linked to original sources
PubMed1997

Effect of T cell subset dose on outcome of T cell-depleted bone marrow transplantation.

T cell depletion using the murine monoclonal antibody (moAb) T10B9 is unique in that the T cell receptor (TCR)gamma delta bearing subset is relatively spared compared to the TCR alpha beta + subset. We evaluated the probabilities of engraftment, acute and chronic graft-versus-host disease (GVHD), relapse, and survival in 273 recipients of marrow T cell depleted using T10B9. Sixty-two patients received marrow from an HLA-identical sibling, 54 patients received partially matched related donor marrow and 157 patients received unrelated donor marrow. Limiting dilution analysis (LDA) was used to estimate total clonable T cell dose in all patients and a modified LDA using moAb-coated immunomagnetic beads was used to estimate TCR alpha beta +, CD4+, and CD8+ T cells in a subset of patients. TCR gamma delta + cell dose was estimated by flow cytometry. Cox proportional hazards regression models were used to assess the impact of T cell subset dose/kg of body weight on outcome. We found a significant association of TCR gamma delta + T cell dose (P = 0.004), but not TCR alpha beta + T cell dose or total clonable T cell dose, with the probability of engraftment. TCR alpha beta +, CD4+, CD8+ and total clonable T cell dose were significantly associated (P < 0.001) with the risks of grade 2-4 acute GVHD in recipients of marrow from related donors but not in recipients of marrow from unrelated donors. Neither total clonable T cell dose nor any T cell subset dose was found to be significantly associated with chronic GVHD, relapse or survival. The results confirm preclinical studies showing TCR gamma delta + T cells promote engraftment. TCR gamma delta + T cells are not associated with an increased risk of acute GVHD while TCR alpha beta T cells are associated with acute GVHD but not engraftment in recipients of marrow grafts T cell depleted using T10B9. These findings support the hypothesis that T cell subsets differentially contribute to alloengraftment and GVHD.

Adolescent↗
PubMed1997

The impact of active herpes simplex virus infection on human immunodeficiency virus load.

The effect of a concurrent herpes simplex virus (HSV) infection on human immunodeficiency virus type 1 (HIV-1) load was evaluated. Sixteen subjects were identified with an active HSV infection and had pre-outbreak, acute-phase, and post-outbreak plasma (n = 16) and peripheral blood mononuclear cell (PBMC) (n = 8) samples for evaluation. All subjects were treated for an acute HSV outbreak with acyclovir for 10 days, followed by chronic prophylaxis. HIV-1 plasma RNA levels were determined by branched DNA, and intracellular HIV gag mRNA copy numbers were determined by quantitative reverse transcriptase-polymerase chain reaction ELISA. Plasma virus load increased a median of 3.4-fold during the acute outbreak (range, 0- to 10-fold; P = .002), while post-outbreak levels (30-45 days after the appearance of lesions) remained above pre-outbreak, baseline levels in some subjects. Intracellular HIV gag mRNA increased during the outbreak as well. Thus, an acute HSV episode can result in increased HIV transcription and plasma virus load.

AIDS-Related Opportunistic Infections↗
PubMed1996

Unrelated donor bone marrow transplantation to treat severe aplastic anaemia in children and young adults.

Alternative donor bone marrow transplantation (BMT) to treat severe aplastic anaemia (SAA) in children and young adults has been complicated by high rates of graft rejection and severe graft-versus-host disease (GVHD). We hypothesized that increased immunosuppression combined with T-cell depletion of the marrow graft would enable successful use of unrelated donor BMT in this disease. Preconditioning consisted of cytosine arabinoside, cyclophosphamide, and total body irradiation (TBI). T-cell depletion was with the anti-CD3 antibody T10B9. GVHD prophylaxis consisted of cyclosporine A. 28 previously transfused patients were transplanted. Nine donor/recipient pairs were HLA matched. As of 1 January 1996, 15/28 (54%) patients are alive, transfusion independent and well with a range of follow-up of 13 months to 8 years (median 2.75 years). Fatalities include all three patients with nonengraftment and all three patients with grade III/IV GVHD. Other fatalities were due to infections or therapy-related toxicity. The incidence >or= grade II acute GVHD was 28%. These data show that in children with SAA who have failed immunosuppression, unrelated donor BMT offers a reasonable hope of long-term survival.

Adolescent↗
PubMed1996

Evaluation of Chiron HIV-1/HIV-2 recombinant immunoblot assay.

In a study to determine the reliability, sensitivity, and specificity of the Chiron RIBA HIV-1/HIV-2 Strip Immunoblot Assay (RIBA HIV-1/2 SIA) for confirmation of human immunodeficiency virus type 1 (HIV-1) and HIV-2 antibodies, 1,263 serum samples from various populations in the United States, Caribbean, Africa, India, and Thailand were evaluated by RIBA HIV-1/2 SIA, and the results were compared with those obtained by an HIV-1 Western blot (immunoblot) assay. All sera were tested by HIV enzyme immunoassay, RIBA HIV-1/2 SIA, and Western blotting. Samples with discrepant results were further tested by an HIV-1 and/or HIV-2 immunofluorescent-antibody assay and HIV-1 p24 antigen assay. The RIBA HIV-1/2 SIA detected all 17 HIV-1 and HIV-2 dually reactive serum samples, all 215 HIV-2-positive serum samples, and 480 of 481 HIV-1-positive serum samples for a sensitivity of 99.8%. Of 548 negative samples, 523 were RIBA HIV-1/2 SIA negative, for a specificity of 95.4%, with 22 (4%) samples interpreted as indeterminate and 3 (0.6%) interpreted as falsely positive. Western blotting detected 391 of 548 negative samples (specificity, 71.4%), with 152 (27.7%) samples interpreted as indeterminate and 5 (0.9%) interpreted as falsely positive. In conclusion, the RIBA HIV-1/2 SIA had a sensitivity comparable to that of Western blotting and could discriminate HIV-1 from HIV-2 in one blot, providing a cost advantage. Because of its high degree of specificity, the RIBA HIV-1/2 SIA further reduced the number of indeterminate results found by Western blotting, providing a more accurate means of assessing seronegative individuals.

AIDS Serodiagnosis↗
PubMed1995

Three new exon 10 glucose-6-phosphate dehydrogenase mutations.

Three previously undescribed mutations of the glucose-6-phosphate dehydrogenase (G6PD) gene have been documented in patients with hereditary non-spherocytic hemolytic anemia (HNSHA). In none of the cases have we been able to obtain a sufficient volume of blood to characterize the residual enzyme biochemically. "G6PD Calvo Mackenna" was due to an A-->G transition in cDNA nucleotide 1138 creating an Aat II site and resulting in a substitution of valine for isoleucine at amino acid 380. "G6PD Riley" was due to a T-->C transition at cDNA nucleotide 1139 also changing the 380 isoleucine, in this case to a threonine. "G6PD Wisconsin" was due to an C-->G transversion in cDNA nucleotide 1177, destroying a Aci I site and resulting in a substitution of glycine for arginine at amino acid 393. All of these mutations were in exon 10, where mutations that cause HNSHA appear to be clustered. We present a list of the 83 mutations of G6PD that have been documented to the end of April, 1995.

Anemia, Hemolytic, Congenital Nonspherocytic↗
PubMed1995

Comparative stabilities of quantitative human immunodeficiency virus RNA in plasma from samples collected in VACUTAINER CPT, VACUTAINER PPT, and standard VACUTAINER tubes.

This study compared the levels of human immunodeficiency virus (HIV) virion RNA in plasma from whole blood collected in VACUTAINER CPT (cell preparation tube), VACUTAINER PPT (plasma preparation tube), VACUTAINER SST (serum separation tube), and standard VACUTAINER tubes with sodium heparin, acid citrate dextrose, sodium citrate, and potassium EDTA used as anticoagulants. Quantitative plasma HIV RNA levels were measured by branched-DNA signal amplification. Blood from all tubes was either processed within 1 to 3 h after collection or stored at room temperature or at 4 degrees C for analysis at 6 to 8 and 30 h postdraw. Immediately separated plasma from sodium citrate CPT tubes held at 4 degrees C maintained better stability of HIV RNA equivalents than whole blood held at room temperature or 4 degrees C. The highest number of HIV RNA equivalents was seen with EDTA VACUTAINER tubes. HIV RNA equivalents in all types of plasma were significantly higher than in SST tubes. Although a decline in HIV RNA equivalents was seen in all collection devices after 30 h, a significantly greater decline in plasma HIV RNA equivalents occurred in acid citrate dextrose VACUTAINER tubes than in citrate CPT, PPT, and standard EDTA VACUTAINER tubes. In order to minimize the variability of quantitative HIV RNA test results, our data suggest that samples collected for a particular assay should be processed at the same time postdraw using a particular tube type throughout a given study.

Anticoagulants↗
PubMed1995

Determination of human immunodeficiency virus RNA in plasma and cellular viral DNA genotypic zidovudine resistance and viral load during zidovudine-didanosine combination therapy.

Eleven human immunodeficiency virus (HIV)-infected subjects on long-term zidovudine (ZDV) therapy had didanosine (ddI) added to their antiretroviral regimen. HIV RNA in plasma was quantitated by branched-DNA signal amplification assay. Peripheral blood mononuclear cell (PBMC) HIV viral DNA was quantitated by PCR. The relative amounts of wild-type (WT) sequence, ddI resistance-associated codon changes (reverse transcriptase [RT] gene codon 65 K-->R [RT K65R], RT 174V, RT I135K/T/V, and RT M184I/V), and ZDV resistance-associated codon change (RT T215Y/F) from HIV RNA in plasma and RT T215Y/F from PBMC viral DNA were determined by differential hybridization of PCR products from 10 of 11 subjects. All subjects had evidence of RT T215Y/F mutation in both RNA in plasma and PBMC DNA at baseline. Subjects with a mixture of WT and RT T215Y/F HIV RNA in plasma at baseline demonstrated a decline in RNA levels in plasma after the addition of ddI. However, after 6 months of ZDV-ddI therapy, WT HIV RNA in plasma was undetectable in all subjects who had demonstrated a mixture at baseline. Subjects with only RT T215Y/F RNA present in plasma at baseline remained so and demonstrated no decline in RNA levels in plasma. In all subjects, no significant changes in PBMC DNA viral load and RT T215Y/F or WT levels were seen. HIV RNA in plasma demonstrated a significantly higher RT T215Y/F mutant/WT ratio than that of PBMC viral DNA, both at baseline and after ZDV-ddI combination therapy in all subjects. No subjects developed mutations associated with ddI resistance at codons 65, 74, 135, and 184 during this study. This study suggests that determination of relative amounts of RT T215Y/F and WT species from HIV RNA in plasma at baseline may be predictive of virologic response during ZDV-ddI combination therapy.

Base Sequence↗
PubMed1994

Stabilities of quantitative plasma culture for human immunodeficiency virus, RNA, and p24 antigen from samples collected in VACUTAINER CPT and standard VACUTAINER tubes.

We evaluated the stability of human immunodeficiency virus (HIV) load markers from blood samples collected in VACUTAINER CPT or standard VACUTAINER brand tubes using sodium heparin or sodium citrate as anticoagulants. Quantitative plasma culture and p24 antigen concentrations were determined, and HIV RNA levels in plasma were measured by both reverse transcription-PCR-enzyme-linked immunosorbent assay (RT-PCR-ELISA) and branched DNA methods. All tubes were stored at room temperature for analysis at 2, 24, 48, and 72 h after the blood samples were drawn. No difference was seen between tube types with respect to the HIV titer in plasma or the positivity rate for all samples that demonstrated a fall in titer over time. Unbound p24 antigen levels in plasma decreased during the initial 48-h period in both tube types. Immune complex-dissociated p24 antigen levels decreased in CPT tubes but not in standard VACUTAINER tubes. The HIV RNA copy number in plasma measured by RT-PCR-ELISA was stable in most subjects and was significantly higher in CPT tubes than in standard VACUTAINER tubes at 24 and 72 h after the blood samples were drawn. The branched DNA probe assay detected a significant decline in HIV RNA equivalent in plasma over 72 h in both collection tubes, the decline being more dramatic in the standard VACUTAINER tube than the CPT tube. Overall, interday variability suggests that samples collected for a particular assay should be processed at the same time after blood is drawn and that a particular tube type be used throughout a given study.

Anticoagulants↗
PubMed1993

Diagnosis of lower-extremity ulcers.

The prevalence of lower-extremity ulcers is expected to increase as the U.S. population ages. Although these ulcers are often difficult to diagnose, the proper etiologic diagnosis can be useful in guiding treatment.

Diagnosis, Differential↗
PubMed1991

Enterobacter cloacae bacteremia in children: a review of 30 cases in 12 years.

A review was performed of the 30 cases of pediatric Enterobacter cloacae (EBC) bacteremia which occurred at our institution during a 12-year period. These 30 cases represented 88% of all cases in which EBC was isolated by blood culture (four other instances were considered contaminants); the rate of isolation of this organism relative to all positive blood cultures was 0.6%. There were 14 patients less than 12 months of age, with 10 less than 2 months of age. Infection was nosocomially-acquired in 17 cases. At the time the positive blood culture was obtained, 5 patients were afebrile, and 8 patients (five immunocompromised) had been receiving parenteral antibiotic therapy to which the organism exhibited in-vitro sensitivity for at least 24 hours. EBC was a constituent of polymicrobial bacteremia in 6 cases; in 5 instances the associated organisms were also gram-negative bacteria. There were a total of 33 underlying medical conditions or foci of infection associated with EBC bacteremia identified in 27 patients, the most common of which were immune-deficiency state (17) and gastrointestinal tract lesions (6). There were 3 patients who died. EBC bacteremia is a relatively rare pediatric infection. It is commonly nosocomially-acquired, and afflicts children who are younger-aged or compromised by underlying medical problems.

Anti-Bacterial Agents↗
PubMed1986

Apocytochrome c induces pH-dependent vesicle fusion.

The ability of apocytochrome c and the heme containing respiratory chain component, cytochrome c, to induce fusion of phosphatidylcholine (PC) small unilamellar vesicles containing 0-50 mol % negatively charged lipids was examined. Both molecules mediated fusion of phosphatidylserine (PS):PC 1:1 vesicles as measured by energy transfer changes between fluorescent lipid probes in a concentration- and pH-dependent manner, although cytochrome c was less potent and interacted over a more limited pH range than the apocytochrome c. Maximal fusion occurred at pH 3, far below the pKa of the 19 lysine groups contained in the protein (pI = 10.5). A similar pH dependence was observed for vesicles containing 50 mol % cardiolipin (CL), phosphatidylglycerol (PG), and phosphatidylinositol (PI) in PC but the apparent pKa values varied somewhat. In the absence of vesicles, the secondary structure of apocytochrome c was unchanged over this pH range, but in the presence of negatively charged vesicles, the polypeptide underwent a marked conformational change from random coil to alpha-helix. By comparing the pH dependencies of fusion induced by poly-L-lysine and apocytochrome c, we concluded that the pH dependence derived from changes in the net charge on both the vesicles and apocytochrome c. Aggregation could occur under conditions where fusion was imperceptible. Fusion increased with increasing mole ratio of PS. Apocytochrome c did induce some fusion of vesicles composed only of PC with a maximum effect at pH 4. Biosynthesis of cytochrome c involves translocation of apocytochrome c from the cytosol across the outer mitochondrial membrane to the outer mitochondrial space where the heme group is attached. The ability of apocytochrome c to induce fusion of both PS-containing and PC-only vesicles may reflect characteristics of protein/membrane interaction that pertain to its biological translocation.

Animals↗