Biomedical subjects
Publications and source records attributed to V Brennan.
Multidrug-resistant tuberculosis (TB) is an increasing problem worldwide, however only three cases have been previously described in transplant recipients, especially involving lung and heart transplant. We describe a case of multidrug-resistant TB in an allogenic bone marrow transplant recipient with good response to second-line therapy.
Previous studies have shown that intravenous immunoglobulin (IVIg) therapy is useful prophylaxis against infection in patients with secondary hypogammaglobulinaemia due to a low-grade lymphoproliferative disease. This randomized double-blind study was undertaken to determine prospectively the dose regime required. 34 such patients received IVIg at either 500 or 250 mg/kg every 4 weeks for 1 year. There was no significant difference in the rates of serious infections between the two groups of patients, which were well matched for disease and laboratory parameters. The rates of infection seen were similar to those in IVIg groups of previous studies and strikingly different from those in the placebo group in the previously randomized placebo-controlled study.
The baculovirus expression system was used to overexpress recombinant human thyroid peroxidase. Sf-9 cells infected with the recombinant virus AcMNPV-hTPO synthesized hTPO protein (hTPO-bac) immunogenic on Western blots when probed with either rabbit anti-TPO peptide sera or pooled human anti-TPO sera (MS12/89). hTPO-bac was a major constituent of the membrane fraction from the infected cells, constituting 14.9% and 10.1% of the 1% deoxycholate-soluble and insoluble fractions, respectively, as judged by densitometry. Recombinant hTPO-bac was extracted from cellular membranes with 1% deoxycholate and partially purified by Sepharose 6B column chromatography. Specific immunoreactivity of MS12/89 to hTPO-bac on microtiter plates was seen using ELISA. Detergent extract from wild-type virus-infected Sf-9 cells was used as background control antigen; no specific reactivity to either hTPO-bac or control antigen was seen with control sera. To determine antigenic potency, MS12/89 was incubated with increasing concentrations of various preparations of hTPO antigen and with ovalbumin as control. The capacity of the partially purified hTPO-bac to immunoneutralize human anti-hTPO standard at 50% inhibition of binding was 0.01 U/microgram hTPO-bac (NIBSC Units), compared with 0.5 U/microgram and 0.06 U/microgram for natural hTPO and CHO-hTPO, respectively. When ELISA was performed using clinical samples of human sera to detect hTPO autoantibodies, results using hTPO-bac correlated well with those using hTPO from Graves' thyroid tissue (r = 0.85, p = 0.02) and those using recombinant hTPO from Chinese hamster ovary cells (hTPO-CHO) (r = 0.85, p = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)
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The effect of serum TSH on rat thyroid peroxidase mRNA levels was studied in order to investigate the regulation of thyroid peroxidase gene expression in vivo. A nearly full-length rat thyroid peroxidase cDNA clone was isolated from a bacteriophage cDNA library synthesized using poly A+ RNA isolated from the thyroids of propylthiouracil-treated rats. cDNA probes derived from this clone were used to study rat thyroid peroxidase mRNA levels in response to the level of serum TSH. Two major rat thyroid peroxidase mRNA bands were detected on Northern blots of total cellular RNA (at 3.2 kb and at 3.7 kb). Injection of thyroxine, which lowered the levels of serum TSH, also lowered the steady-state levels of both rat thyroid peroxidase mRNAs, whereas treatment with methimazole, which increased serum TSH, increased both rat thyroid peroxidase mRNA levels. In hypophysectomized rats 10 days postoperative, very low levels of thyroid peroxidase mRNA were observed. Injection of bovine TSH (1 IU/day) increased rat thyroid peroxidase mRNA expression, preferentially in the 3.2 kb band. These results clearly demonstrate that TSH regulates rat thyroid peroxidase mRNA levels in vivo.
Chronic lymphocytic leukemia (CLL) is a disorder with multiple defects leading to an increased susceptibility to infection. Hypogammaglobulinemia is present in about 20% to 70% of patients with CLL. Intravenous immunoglobulin (IVIG) supplementation (400 mg/kg body weight every 3 weeks) prevented bacterial infections in these patients. An ongoing study is being conducted to compare doses of 250 mg/kg/mo with those of 500 mg/kg/mo in 36 patients included so far. As of this writing, the rate of infection in the two treatment groups was not significantly different, and no substantial loss of protection against bacterial infection was found in the lower-dose group. It seems likely that the lower dose is almost as effective as the standard therapy. If this is so, cost savings would be substantial.
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Bacterial infection is an important cause of morbidity and mortality in patients with B-cell tumors; this is related to their secondary hypogammaglobulinaemia. Two studies of intravenous replacement therapy [IVIg] have been performed in such patients: a crossover study over two years and a randomised, multicentre study over one year. Both involved infusions of IVIg [400 mg/Kg] or an equivalent volume of saline every three weeks for one year. In both studies, serious bacterial infections were considerably reduced by IVIg. Viral and fungal infections were uncommon. In the crossover study bacterial infections were more frequent in periods in which patients serum IgG levels were below the normal range [less than 6.4 g/l]. The sites of bacterial infection were similar in these studies to those in previously published reports, namely respiratory tract, skin, urinary tract and blood. There were a few mild adverse reactions which were related to the rate of infusion, but no serious toxic effects. Haematological parameters were not significantly changed by IVIg at this dose and disease progression did not appear to be changed.
A randomized crossover study of prophylactic immunoglobulin (IgG) therapy was performed in patients with chronic lymphocytic leukaemia (CLL) or non-Hodgkin's lymphoma (NHL). Twelve patients with hypogammaglobulinemia or a history of recurrent infections received infusions of IgG or placebo intravenously (IV) every 3 weeks for 1 year. They were then switched to the alternative preparation for another year. The number of serious bacterial infections was significantly less (P = .001; Mainland's cross-over method) in the months in which patients received IgG. Serious bacterial infections showed a trend to be associated with an IgG level less than 6.4 g/L (P = .046; Fisher's exact test).
Twelve patients, ten with common variable hypogammaglobulinaemia and two with hypogammaglobulinaemia secondary to chronic lymphocytic leukaemia (CLL), have been taught to self-infuse their intravenous immunoglobulin replacement therapy. Follow-up of these patients has shown that regular self-infusion at home is feasible and safe. There have been no anaphylactic or other serious reactions. Excellent patient compliance results from greater convenience and control over their own lives, in addition to time and money saved by the hospital.
ScV-L is a simple double-stranded RNA virus of yeast, consisting of a 4.8 kilobase pair double-stranded RNA (L) encapsidated in isometric particles composed mainly of one polypeptide (ScV-Pl) of 88,000 daltons. L encodes ScV-Pl. There is a capsid-associated RNA polymerase that synthesizes in vitro predominantly single-stranded RNA. We show that this polymerase activity is a transcriptase, at the least one product of which is the mRNA for ScV-Pl. The transcript, like its template, is uncapped.
We investigated the possibility of sequence of homology between yeast DNA and one of the double-stranded RNAs present in many strains of Saccharomyces cerevisiae. These double-stranded RNAs are encapsidated in virus-like particles, which appear to be similar to the viruses of higher fungi. Contrary to a recent report (M. Vodkin, J. Virol. 21:516--521, 1976), we find no such homology.
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