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Biomedical subjects

H M Jones

Publications and source records attributed to H M Jones.

At least 73 records · Page 4Linked to original sources
PubMed1986

Allogeneic bone marrow transplantation for adult leukaemia with soy bean lectin fractionated marrow.

A heterogeneous group of 11 consecutive patients with leukaemia have been transplanted successfully with allogeneic marrow depleted of T lymphocytes by soy bean lectin agglutination and neuraminidase-treated sheep erythrocyte rosetting. Effective depletion was achieved, leaving less than 1% of donor T lymphocytes. Despite the small numbers of nucleated cells infused (mean 0.14 X 10(8)/kg) there was only moderately delayed recovery of peripheral blood counts and no graft failures have occurred. Standard methotrexate prophylaxis against graft-versus-host disease (GVHD) was also employed in the first four transplants. Only one case of mild grade I (skin only) acute GVHD has occurred and there has been no chronic GVHD to date. The group of patients show an actuarial cumulative survival of 55% with two early infective deaths (days 42 and 44 post-transplant) and three late deaths, two with leukaemic relapse and the third with probable viral encephalitis. The longest survivor is now 1109 days post-transplant. This series indicates that lectin fractionation of donor marrow, previously employed mainly in children, can also be effective in minimizing GVHD in adults without endangering successful engraftment.

Adolescent↗
PubMed1985

A role for inhibin in the control of follicle-stimulating hormone secretion in male rats.

We examined the relationship of testosterone (T) and porcine follicular fluid (pFF) in the negative feedback control of FSH and LH secretion in adult male rats. Either at the time of castration (acute) or at least 30 days after castration (chronic), we implanted T-filled Silastic capsules, which were 2 mm, 10 mm, or 30 mm long; empty capsules (30 mm) served as controls. Seven days later, we injected either 0.15 ml of pFF or saline (i.v.), decapitated the rats 6 hours later, and collected trunk blood for subsequent serum analysis of FSH, LH, and T by RIA. In the acute groups, T implants suppressed the postcastration rises in plasma FSH and LH levels in a dose-dependent manner, with only the largest implant, 30 mm, able to return them to intact levels. PFF injection significantly suppressed FSH levels in intact and acute rats but had no effect on serum LH. In chronic rats, T therapy for 7 days suppressed plasma LH levels in a dose-dependent relationship, yet did not do so to plasma FSH levels. FSH levels were significantly higher in rats with the 30 mm T implants than in intact rats, but were significantly suppressed as compared to chronic controls. PFF significantly suppressed serum FSH levels in all chronic groups with the chronic controls showing the greatest amount of suppression. We conclude that the role for inhibin in the normal control of FSH secretion is that of a secondary modulator which is superimposed on, yet independent of, the steroid feedback mechanism. At any given moment this modulation is dependent upon the secretory activity of the FSH gonadotrope.

Animals↗
PubMed1985

Hodgkin-cell leukaemia of B-cell origin.

A case of lymphocyte-depleted nodular sclerosing Hodgkin's disease with a terminal leukaemic phase is described. Circulating Hodgkin cells were shown to be of B-cell origin by immunological phenotyping and the demonstration of clonal immunoglobulin gene rearrangement.

Aged↗
PubMed1985

Transcription of the Escherichia coli fumarate reductase genes (frdABCD) and their coordinate regulation by oxygen, nitrate, and fumarate.

The fumarate reductase enzyme complex allows Escherichia coli to grow anaerobically with fumarate as a terminal electron acceptor for oxidative phosphorylation when the preferred compounds oxygen and nitrate are not available. We used the pKO promoter test vectors to identify a single promoter for the frdABCD genes which encode fumarate reductase. Expression of galactokinase from the frd promoter-galK operon fusion plasmid was repressed by oxygen and by nitrate and was induced by fumarate, indicating that frd gene expression is regulated at the transcriptional level by these terminal electron acceptors. S1 nuclease analysis, using a single-stranded DNA probe from the frd promoter region and mRNA isolated from a fumarate reductase-induced culture, revealed that the frd mRNA transcript initiates with an adenine residue 93 bases prior to the start of frdA translation. No promoters internal to the frd genes were revealed with the plasmid promoter screening system. S1 nuclease analysis revealed that the frd mRNA terminates in a uridine-rich region centered at 46 bases after the last codon of frdD. A stem and loop structure previously described as the growth rate-dependent attenuator for the linked ampC gene precedes the frd mRNA terminus. This result confirms the proposal that the stem and loop structure serves the dual role of a frd terminator anaerobically and an ampC attenuator aerobically. The four frd genes encoding the subunits of the fumarate reductase complex thus comprise an operon which is regulated at the transcriptional level in response to the cellular availability of the alternate electron acceptors oxygen, nitrate, and fumarate.

Base Sequence↗
PubMed1985

Bone marrow T cell colony-forming cells: studies of their origin and use in monitoring T cell-depleted bone marrow grafts.

Peripheral blood T cell colony forming cells (T-CFC) are mature T cells. When blood was fractionated into sheep red blood cell receptor positive (E+) and negative (E-) fractions, T cell colony growth was largely restricted to the E+ population. When bone marrow was similarly fractionated, many colonies grew from the E- cells but myeloid colonies also grew making interpretation of colony numbers difficult. We have, therefore, also assessed T cell proliferation during culture as an expansion index (EI) by determining the absolute number of T cells pre and post culture. This data shows that T cell expansion is on average nine times greater in the E- marrow fraction than in the E+ fraction. Studies are presented suggesting that this is because marrow E- cells contain appropriate accessory cells and that high numbers of T cells inhibit T cell growth. The cells giving rise to bone marrow T cell colonies thus appear to be contaminating mature T cells rather than pre-thymic progenitor cells. We have measured T cell expansion in culture as a sensitive assay of T cell contamination following procedures to remove T cells from bone marrow grafts for the prevention of graft versus host disease (GVHD).

Bone Marrow↗
PubMed1984

The effect of cyanide on the uptake of gold by red blood cells.

Cyanide markedly increased the rate of uptake of gold by red blood cells when incubated with sodium aurothiomalate, a polymeric gold complex. Thiocyanate had no significant effect on gold uptake. The effect of cyanide was demonstrated to be due to the conversion of aurothiomalate to the complexion, aurocyanide, which is rapidly taken up by red blood cells. At a low ratio (1:20) of cyanide to aurothiomalate, cyanide appeared to act as a shuttle to carry gold into red blood cells. Tobacco smoking is known to increase the concentrations of gold in red blood cells in patients treated with aurothiomalate. The present data indicate that this effect of smoking is most likely due to cyanide inhaled in tobacco smoke and not to thiocyanate, a circulating metabolite of cyanide. An effect of cyanide on the uptake of polymeric gold complexes to target cells such as polymorphonuclear leukocytes and monocytes is suggested.

Aurothioglucose↗
PubMed1983

Ultrastructural morphometry of the myocardium of Thunnus alalunga.

The common ventricle in the heart of the Thunnus alalunga was studied. The ventricular myocardium consists of an outer compact layer and a thick inner spongy layer. The compact layer has slightly larger cells (4-6 microns diameter) than the spongy layer (2.5-5 microns diameter). Ultrastructurally the myocardium displays normal arrangements of myofibrils and mitochondria. The sarcoplasmic reticulum is poorly developed. The intercalated discs are simple with the fascia adherens being the most frequent junctional type observed; occasionally a desmosome was seen. Nexus type junctions are present but are unassociated with the intercalated discs. There are no t-tubules evident but the plasmalemma exhibits numerous caveolae which rarely form couplings with the sarcoplasmic reticulum. A morphometric analysis of the volume percent of mitochondria and myofibrils showed that the myocardial cells in the spongy layer of the heart have a significantly greater volume percentage of mitochondria than the compact layer. No significant differences were found between myocardial regions when the volume percentages of myofibrils were compared. The physiological studies revealed that the albacore tuna has heart rates (120 bpm) and ventricular blood pressures (100 mmHg) that are among the highest reported for fish.

Animals↗
PubMed1983

In vivo 5' terminus and length of the mRNA for the proton-translocating ATPase (unc) operon of Escherichia coli.

The promoter for the proton-translocating ATPase (unc) operon of Escherichia coli was localized by using a plasmid promoter-screening vector system. S1 nuclease analysis, using the appropriate single-stranded DNA probe from this promoter region and in vivo mRNA, revealed that the 5' end of the in vivo unc mRNA initiates with a guanine residue 73 bases before the start of the proposed gene 1 or 474 bases before uncB. An in vivo unc mRNA species of approximately 7,000 nucleotides in length which initiates in the unc promoter region was shown to exist by RNA-DNA hybridization analysis. This unc mRNA species (based on DNA sequence analysis) is sufficient in length to contain all nine genes, gene 1 and uncBEFHAGDC. That gene 1 is cotranscribed with the unc genes was confirmed by using hybridization probes containing the promoter-proximal (gene 1) or -distal gene (uncC). No strong internal promoters within the unc operon were revealed with either the promoter-screening vector system or the RNA-DNA hybridization analysis. The 5' terminus and the length of the unc mRNA were found to be identical in cells grown either aerobically or anaerobically. The level of unc operon expression, as assayed with the unc promoter plasmid, did not significantly differ when cells bearing the plasmid were grown either aerobically or anaerobically.

Adenosine Triphosphatases↗
PubMed1983

Two cases of dipylidiasis (dog tapeworm infection) in children: update on an old problem.

Children in households with dogs and cats may become infected with the dog tapeworm more frequently than suspected. Because of age-appropriate hand-to-mouth exploration, young infants and toddlers, through contact with fleas on pets, floors, and furnishings, are particularly susceptible. Knowledge of the life cycle of this animal parasite and the manner in which children acquire and demonstrate infection can lead to early diagnosis and effective treatment.

Animals↗
PubMed1982

Hepatotoxicity of bile acids in rabbits: ursodeoxycholic acid is less toxic than chenodeoxycholic acid.

The hepatotoxic effects of cholelitholytic bile acids, ursodeoxycholic and chenodeoxycholic acids, were compared with each other and with those of lithocholic acid, a known hepatotoxic bile acid, in the rabbit. Male New Zealand white rabbits were fed regular laboratory chow containing ursodeoxycholic, chenodeoxycholic, or lithocholic acid at a concentration of 0.5 per cent (w/w) for 14 days. The control group was fed the chow without added bile acids. The mortality rate was highest (six of 12) in the lithocholate group, intermediate (two of eight) in the chenodeoxycholate group, and lowest (none of six) in the ursodeoxycholate group. Light microscopy of the liver revealed fibrosis, inflammation, and bile duct proliferation in the portal regions in the three experimental groups; however, the lesions in the lithocholate and chenodeoxycholate groups were more severe and often associated with periportal extension of fibrosis and focal necrosis of the parenchyma. In addition, electron microscopy revealed distortion of bile canaliculi, conspicuous bundles of intermediate-sized filaments, expansion of pericanalicular cytoplasmic matrix due to apparent accumulation of microfilaments, prominence of lysosomes, and fragmentation of cisternae of the rough endoplasmic reticulum. These ultrastructural changes were less marked and often absent in the ursodeoxycholate group. The serum L-alanine aminotransferase activity increased 5- to 6-fold in the lithocholate and chenodeoxycholate groups, whereas it remained less than 2-fold of the control level in the ursodeoxycholate group on day 14. The serum lithocholate concentration was markedly elevated to comparable levels in all three groups, whereas ursodeoxycholate was highly increased in the ursodeoxycholate group but undetectable in the other groups at the time of sacrifice. It is concluded that (1) although the oral administration of three bile acids induces hepatic injuries in the rabbit, ursodeoxycholate causes less severe injury than do the other two, (2) the advantage of ursodeoxycholate versus chenodeoxycholate is probably relative rather than absolute, (3) lithocholate formed through metabolic conversion from ursodeoxycholate may be responsible for the most part for hepatotoxicity, and (4) it is possible that the concurrent presence of ursodeoxycholate may mitigate lithocholate's hepatotoxicity.

Animals↗
PubMed1981

A two-site immunoradiometric assay for the MB isoenzyme of creatine kinase.

A two-site immunoradiometric assay for myocardial creatine kinase MB isoenzyme is described. The method utilizes immobilized anti-human creatine kinase BB antibodies and 125I-labelled anti-human creatine kinase MM antibodies and can specifically detect creatine kinase MB in the presence of approximately 1000-fold excess of creatine kinase MM or BB. Native creatine kinase MB prepared from human heart and creatine kinase MB prepared by hybridisation of purified human creatine kinase MM and creatine kinase BB appeared to react identically in the assay. Serum estimations on patients with suspected myocardial infarction correlated with the presence of an MB band on electrophoresis but preliminary results suggest that the two-site immunoradiometric assay may be more sensitive.

Animals↗
PubMed1981

Ultrastructural localization of cholesterol by enzyme histochemistry.

The histochemical localization of cholesterol using oxidized diaminobenzidine as the final reaction product was studied at the electron microscopical level and compared with the digitonin method of cholesterol localization based on cholesterol digitonide as the final reaction product. Tissue chopper sections of fixed rat adrenal glands were incubated at 37 degrees C in a medium consisting of 0.8 units/ml cholesterol oxidase, 1.4 units/ml cholesterol ester hydrolase, 50 units/ml horseradish peroxidase, 0.5 mg/ml diaminobenzidine, 0.1% v/v Triton X-100 (or Surfal) and an endogenous peroxidase inhibitor in 0.1 M phosphate buffer, pH 7.0. An electron-dense osmiophilic reaction product was observed in many lipid droplets, intracellular vesicles and focally around mitochondria. Appropriate control experiments indicated that deposition of reaction product depended on the presence of cholesterol and the necessary enzymes. Comparison studies using digitonin confirmed the presence of cholesterol in the lipid droplets, but ultrastructural distortion limited the resolution of the more discrete deposits of cholesterol than the digitonin method because it does not cause distortion of cellular ultrastructure attributed to the formation of cholesterol digitonide. The enzyme method or a combination of enzyme and digitonin enable localization of free, esterified or total cholesterol.

3,3'-Diaminobenzidine↗