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Biomedical subjects

J Rees

Publications and source records attributed to J Rees.

At least 37 records · Page 2Linked to original sources
PubMed1990

Contact sensitivity to dinitrochlorobenzene is impaired in atopic subjects. Controversy revisited.

If there is a primary dysfunction of the immune system in atopic eczema it might be reflected in altered capacity to generate delayed-type hypersensitivity. Therefore, the dose-response relationships for contact sensitization were determined for 22 patients (10 men) with minimal atopic eczema and compared with those from 27 nonatopic, healthy control subjects (12 men). Sensitization was induced with 30 micrograms of dinitrochlorobenzene applied to the thigh. Four weeks later the subjects were challenged with three doses of dinitrochlorobenzene (8.8, 12.5, and 17.7 micrograms), and responses were quantified with calipers as change in skinfold thickness at 48 hours. Atopic patients were significantly less responsive with smaller reactions at all challenge doses and a flatter challenge dose-response curve than that for control subjects. Thus, proper quantitative comparisons have shown that subjects with minimal atopic eczema do not mount a normal contact hypersensitivity response. However, it is not clear whether this is a consequence of the atopic state per se or is related to the presence of even a minor degree of eczema.

Adolescent↗
PubMed1989

Differentiation induction therapy of myelodysplastic syndromes.

Myelodysplastic syndromes are a heterogenous group of haemopoietic stem cell disorders characterized by dysplastic haematopoiesis and a defective maturation of a slowly expanding or sometimes of a stable population of haemopoietic progenitors. Defective maturation, which may involve one or more of the marrow cell lineages is regarded as the central pathophysiological feature of myelodysplastic syndromes. Patients with myelodysplastic syndromes respond poorly to conventional cytotoxic chemotherapy, frequently developing a prolonged marrow aplasia. The alternative and more appropriate form of therapy is differentiation induction therapy. The results of few preliminary clinical studies in myelodysplastic patients showed that a combination of differentiating agents is superior to single agent differentiation therapy. An extensive pre-clinical screening of the response of fresh cells from myelodysplastic patients in primary culture is needed to establish the optimal doses and conditions for significant synergies between various differentiating agents followed by large controlled randomized clinical trials based on differentiation induction therapy for patients with myelodysplastic syndromes.

Cell Differentiation↗
PubMed1989

Cooperative effects of human recombinant granulocyte-macrophage colony stimulating factor and human recombinant erythropoietin in inducing erythroid differentiation of the human erythroleukaemia cell line K 562 clonogenic cells.

Human acute erythroleukaemia arises from the inability of the haemopoietic stem cell to differentiate. K 562 cell line provides a homogeneous population of primitive erythroleukaemic cells that are at the same point of differentiation. The effect of human recombinant granulocyte-macrophage colony-stimulating factor and human recombinant erythropoietin on the differentiation of K 562 clonogenic cells was studied. Cells were cultured in methylcellulose culture for 5 days at 37 degrees C in humidified atmosphere containing 5% CO2 in air and scored for erythroid differentiation by benzidine staining. A combination of both growth factors induced erythroid differentiation in more than 80% of K 562 clonogenic cells. This combination may be useful in the treatment of patients with erythroleukaemia.

Cell Differentiation↗
PubMed1989

The role of ABO blood group compatibility in heart transplantation between closely related animal species. An experimental study using the vervet monkey to baboon cardiac xenograft model.

The role of ABO blood group compatibility on graft survival when transplantation is performed between closely related animal species is uncertain. Heart transplants (in the neck) were performed between donor vervet monkeys and recipient baboons; no immunosuppressive therapy was given. Survival in ABO-compatible pairs (group 1, n = 9) was for a mean of 10.3 (+/- 5.2) days, which was not significantly different from that in ABO-incompatible pairs (group 2, n = 9: mean survival 7.3 +/- 5.6 days). In group 2, however, three hearts were rejected hyperacutely within 60 minutes, whereas in group 1 only one heart was rejected within 24 hours (not significant). Preformed anti-vervet monkey antibody was present in only one of 18 baboons, but developed in eight others. ABO-specific antibodies were present in all nine group 2 baboons and increased in titer in six cases. Histopathologic features of vascular (humoral) rejection, sometimes associated with cellular infiltration, were seen in a majority of hearts in both groups. Though the number of animals in this study was small, ABO-incompatibility would not appear to be a major factor in cardiac xenograft survival when transplantation is performed between closely related primate species, though early hyperacute rejection would seem more likely to occur when blood group incompatibility is present.

ABO Blood-Group System↗
PubMed1988

Plasma from myasthenia gravis patients reduces acetylcholine receptor agonist-induced Na+ flux into TE671 cell line.

Plasma from myasthenia gravis patients was tested for its ability to inhibit agonist-induced 22Na+ influx into the TE671 cell line that expresses human acetylcholine receptors. Reduced 22Na+ influx correlated weakly with the total anti-acetylcholine receptor antibody level in the plasma, and was also related to the presence of antibody directed against the agonist binding site, as detected by inhibition of 125I-alpha-bungarotoxin binding. However, in some cases there was inhibition of 22Na+ flux without evident anti-alpha-bungarotoxin binding site antibody. We conclude that in most patients antibodies that interfere with 22Na+ influx do so by blocking the agonist binding site. However, in some cases antibodies may be directed at the Na+ ion channel or some important functional determinant.

Adult↗
PubMed1988

Application of radioimmunoassay to monitor treatment of human cerebral gliomas with bleomycin entrapped within liposomes.

A radioimmunoassay was assessed for its suitability for monitoring the blood and urinary concentrations of bleomycin entrapped within large unilamellar liposomes in patients receiving therapeutic doses of the drug. Bleomycin entrapped within liposomes was administered by direct intracerebral injection to three patients with grade III to IV cerebral gliomas, twice weekly for up to six weeks. No clinically important toxic effects were observed which could have been attributed to these preparations, although all three patients showed progressive deterioration in their clinical condition. This type of treatment may be more beneficial to patients at an earlier stage of their disease.

Adolescent↗
PubMed1988

Lay theories of schizophrenia.

Subjects completed two brief questionnaires, one concerning the description of, and attitudes towards schizophrenia and schizophrenics and the second on the possible cause of schizophrenia. Both questionnaires yielded a clearly interpretable factor structure and the relationship between the cause and 'symptoms' was examined. The results are discussed in terms of the range, determinants and structure of lay beliefs in mental illness, particularly schizophrenia.

Adult↗
PubMed1988

A double-blind comparison between nitrazepam, lorazepam, lormetazepam and placebo as preoperative night sedatives.

Benzodiazepines are used as hypnotics to reduce anxiety and give a good night's sleep on the night prior to surgery. In a double-blind procedure, patients were given either lorazepam (2 mg or 4 mg), lormetazepam (1 mg or 2 mg), nitrazepam 10 mg or placebo. Measures were taken of sleep, anxiety, memory and after-effects. There was no evidence that the drugs reduced anxiety, nor evidence of amnesia. Quality and length of sleep was shown to be better for nitrazepam (P less than 0.05), lorazepam 2 mg (P less than 0.05) and lorazepam 4 mg (P less than 0.01), compared with placebo. However, significantly higher ratings of clumsiness and confusion as after-effects were found with nitrazepam (P less than 0.05), and clumsiness (P less than 0.005), slurred speech and blurred vision (P less than 0.01), sleepiness, nausea, weakness and confusion (P less than 0.05) with lorazepam 4 mg. It was concluded that lorazepam 2 mg produced the greatest net benefit.

Adult↗
PubMed1988

Cardiac allotransplantation across major blood group barriers in the baboon.

In heterotopic heart transplantation experiments in Chacma baboons, some of the animals were significantly immunosuppressed with cyclosporine, resulting in prolonged cardiac allograft survival. ABO blood group incompatibility between recipient and donor did not significantly influence mean allograft survival, but early hyperacute (vascular) or acute (cellular) rejection occurred only when ABO incompatibility was present.

ABO Blood-Group System↗