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Biomedical subjects

A D Bryceson

Publications and source records attributed to A D Bryceson.

At least 55 records · Page 3Linked to original sources

High-dose sodium stibogluconate treatment of cutaneous leishmaniasis in Kenya.

Cutaneous leishmaniasis caused by Leishmania aethiopica usually responds poorly to conventional doses of pentavalent antimonial drugs. We treated three patients with cutaneous leishmaniasis acquired in Kenya, presumed or documented to be caused by L. aethiopica, with intravenous sodium stibogluconate, 18 to 20 mg Sb/kg body-weight twice daily for 30 days. All patients had a good response to treatment, with disappearance of parasites from skin smears and cultures after 14 to 27 days, clinical healing of the lesions, and no recurrence during a three to 18-month follow-up. Side effects of treatment were minor. We conclude that this high dose sodium stibogluconate regimen is safe and effective for treating cutaneous leishmaniasis caused by L. aethiopica in Kenya.

Adolescent↗

A comparison of three dosage regimens of sodium stibogluconate in the treatment of visceral leishmaniasis in Kenya.

A prospective randomized trial of three dosage regimens of sodium stibogluconate (Pentostam; Wellcome Foundation, London) to treat visceral leishmaniasis was conducted. Previously untreated patients were randomized to receive 31 doses of sodium stibogluconate (10 mg Sb/kg of body weight per dose) administered once daily for 31 days (group A), every 12 hr for 15 days (group B), or every 8 hr for 10 days (group C). Of the 29 patients who completed treatment, seven of 10 in group B and all of the patients in groups A and C responded to treatment and remained well for one year. One patient in group B failed to respond to treatment, and two others in group B initially responded to treatment but relapsed six weeks after discharge. None of the treatment regimens was toxic. Parasites disappeared from splenic aspirates most quickly and hemoglobin levels rose most rapidly in patients receiving sodium stibogluconate every 8 hr. Treatment of visceral leishmaniasis in Kenya with sodium stibogluconate at a dose of 10 mg Sb/kg every 8 hr for 10 days appears to be a safe alternative to conventional treatment. Its efficacy should be confirmed in a larger number of patients.

Adolescent↗

Comparison of microscopy and culture in the detection of Leishmania donovani from splenic aspirates.

Three culture media were compared with Giemsa-stained smears for the detection of Leishmania in splenic aspirates from Kenyan patients with visceral leishmaniasis. Ninety-nine splenic aspirates obtained from 26 patients at various times before, during, and after treatment were cultured in Schneider's Drosophila medium and RPMI medium 1640 (each supplemented with 20% fetal bovine serum) and McConnell's modification of Senekje's medium overlayed with 0.9% saline. From 13 splenic aspirates obtained before treatment, amastigotes were identified microscopically in all and promastigotes were cultured in 12. During and after treatment, Schneider's medium was the most sensitive method for detecting parasites, followed by microscopic examination of stained smears which was more sensitive than either of the other two media tested. Results indicate that, for initial diagnosis, both culture and direct microscopy of aspirates should be employed.

Culture Media↗

Quantitation of amastigotes of Leishmania donovani in smears of splenic aspirates from patients with visceral leishmaniasis.

During a 20-month period, more than 500 splenic aspirations were performed in 89 patients with suspected or proven visceral leishmaniasis. The two complications which occurred (intra-abdominal bleeding and penetration of the intestine in one patient each) both resolved with conservative management. Parasite density in splenic aspirate smears was graded on a logarithmic scale from 0 (no parasites in 1,000 microscopic fields) to 6+ (greater than 100 parasites per microscopic field). Among 46 newly diagnosed and 17 relapsed or drug-resistant patients with visceral leishmaniasis, the average initial parasite grade was 4.35 +/- 0.92 (mean +/- SD) and 4.15 +/- 1.37, respectively. The grading system was useful in measuring the speed of response to treatment, and in distinguishing slow responders from nonresponders. This was especially valuable for managing patients with drug-resistant visceral leishmaniasis. The system also provided a means of comparing the efficacy of different treatment regimens, and for calculating the optimum duration of treatment.

Adult↗

Immunosuppression in Kenyan visceral leishmaniasis.

Cell-mediated immune responses were evaluated in 15 patients with active visceral leishmaniasis from Masinga location in eastern Kenya where the disease is endemic. Age and sex matched controls were selected from a village school in the same area. In vivo studies were carried out by skin testing with leishmanin, tuberculin, streptococcal and candida antigens. Lymphocyte blastogenic transformation to the mitogens phytohaemagglutinin (PHA) and concanavalin A (Con A) and the antigens purified protein derivative (PPD), streptokinase-streptodornase (SKSD) and leishmanial antigen (LA) was studied in vitro. The results showed that immunosuppression in visceral leishmaniasis in Kenya was both specific and non-specific. In the majority of patients there was complete anergy to all antigens in vivo and in vitro. The suppression of responses to mitogens was less marked. Recovery of non-specific responses preceded the development of specific immunity. In a small number of patients (23%) immune unresponsiveness to leishmanial antigens persisted 1 year after parasitological cure.

Adolescent↗

Experience with mebendazole in the treatment of inoperable hydatid disease in England.

Eleven heterogeneous patients with inoperable hydatid disease were treated with high doses of oral mebendazole, up to 200 mg/kg/day for 16 to 48 weeks. Toxicity was not encountered. Despite careful assessment it proved difficult critically to evaluate the efficacy of mebendazole. In four patients chemotherapy appeared to have been at least partially successful and success seems to have correlated with serum levels in excess of 100 ng/ml one to three hours after dosage. The problems of assessment are discussed and the need for controlled trials of mebendazole in hydatid disease are stressed.

Adolescent↗

The effect of delayed addition of antigen and 'E' rosetting on the proliferative response to mycobacterial antigens of peripheral blood lymphocytes from normal individuals or from patients with tuberculosis or leprosy.

Some suppressor cells are reported to lose their activity when precultured without stimulus in vitro. We have investigated the role of such suppressors in responsiveness to mycobacterial antigens of peripheral blood mononuclear cells (PBMNC) from patients with leprosy or tuberculosis, or from normal donors. Delayed addition of mycobacterial antigens (Mycobacterium leprae, Mycobacterium vaccae and Mycobacterium tuberculosis), but not of a fungal antigen (Candida albicans) caused enhanced responses using PBMNC from most normal donors, or tuberculoid leprosy (TT/BT) patients. However, the effect was less common using PBMNC from the lepromatous leprosy (BL/LL) group. (P less than 01.01, using M. leprae, relative to the TT/BT group), suggesting that this type of suppression reflects a normal mechanism, which is diminished rather than increased in anergic patients. Delayed addition of antigens to 'E'-rosetting cells did not result in enhanced responses. However, the different effects of 'E'-rosetting on the responses to the mycobacterial antigens of cells from normals, TT/BT and BL/LL patients, suggested that there may be two types of proliferative response to these antigens.

Antigens, Bacterial↗

Cutaneous leishmaniasis and leprosy.

Eight patients who had concomitant leprosy and leishmaniasis are described. Two patients with lepromatous leprosy had high resistance leishmaniasis, implying that the immune deficiency in lepromatous leprosy is specific to Mycobacterium leprae.

Adolescent↗

Cell-mediated immunity during natural measles infection.

Natural measles causes prolonged depression of cell-mediated immunity yet little is known as to how the infection influences lymphocyte function. Therefore, we studied the properties and function of lymphocytes during and after measles. The number and proportion of circulating thymus-derived lymphocytes was low during the acute stage of measles, and at this time 37% of these cells showed positive immunofluorescent staining for measles virus after stimulation with phytohemagglutinin. 7% of B cells were shown to contain virus but their numbers did not alter during the infection. Acute-phase lymphocytes, when stimulated, yielded infective virus and half were killed on incubation with autologous serum and complement. In acute measles the increase in [(3)H]-thymidine uptake of lymphocytes when stimulated with an optimal dose of PHA was normal in media with 10% fetal calf serum and low in media containing 10% autologous serum: the mean values were 56.8+/-34.1 and 23.7+/-25.9 cpm x 10(3) per 10(6) lymphocytes, respectively. Stimulation of acute-phase lymphocytes by Candida antigen was also low in media containing autologous serum averaging 1.2 x 10(3) cpm per 10(6) lymphocytes. On recovery 4-6 wk later this rose significantly to 18.9+/-19.8. The mean migration index of leukocytes to heat-killed candida cells in acute measles was 0.84+/-SD 0.08, and this fell significantly to 0.75+/-SD 0.08 4 wk later. Thus, depletion of T cells, an inhibitor of lymphocyte proliferation in the serum and a possible defect in antigen processing, interacts to depress cell-mediated immunity in measles.

Antigens, Fungal↗

Dangerous reactions to treatment of onchocerciasis with diethylcarbamazine.

Nine Nigerians with severe onchocerciasis who were treated with diethylcarbamazine developed clinical changes, ranging in severity from mild itching to distress, cough, and syncope. Physiological changes (fever, tachypnoea, tachycardia, or hypotension) were seen in eight. In five patients the systolic blood pressure fell by more than 25 mm Hg, and one patient collapsed on attempting to sit up. Circulating eosinophils decreased profoundly in all cases, reaching their lowest levels just before or during the clinical and physiological changes. A fall in serum complement (c3) accompanied the reaction but there was no fall in antibody titre. Diethylcarbamazine probably acts on the parasite's cuticle, thus exposing it to the body's defence mechansims. The reaction coincides with the death of microfilariae, and the accompanying physiological changes may be so severe, even in generally healthy patients, the treatment should perferably be started in hospital.

Adolescent↗