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Biomedical subjects

R N Davidson

Publications and source records attributed to R N Davidson.

At least 37 records · Page 2Linked to original sources
PubMed1998

Practical guide for the treatment of leishmaniasis.

This article summarises the clinical features of visceral, cutaneous and mucocutaneous leishmaniasis, and leishmaniasis in HIV-coinfected patients. The characteristics and clinical use of pentavalent antimonials and the traditional drugs used in all forms of leishmaniasis are described. There have been important developments in therapy, such as aminosidine (paromomycin) conventional amphotericin B and lipid-associated amphotericin B. In most cases of leishmaniasis there is a range of treatment options which is determined by the geographical and clinical features. This review is intended to assist the clinician in choosing treatment and in using unfamiliar drugs with safety and efficacy.

Animals↗
PubMed1997

Treatment of visceral leishmaniasis in children with liposomal amphotericin B.

We used liposomal amphotericin B as first-choice treatment of visceral leishmaniasis in 106 immunocompetent children who acquired the infection in a temperate region of southern Europe (Italy) where Leishmania infantum visceral leishmaniasis is endemic. The aim of the study was to identify the minimum total dose of liposomal amphotericin B needed to cure the infection in children and reduce the period of hospitalization. We conclude that the optimal regimen in immunocompetent children with L. infantum visceral leishmaniasis to be a total dose of 18 mg/kg of liposomal amphotericin B (3 mg/kg per day for 5 days, followed by 3 mg/kg administered as an outpatient regimen on day 10).

Adolescent↗
PubMed1997

AIDS and leishmaniasis.

Explore the source record for details and available documents.

AIDS-Related Opportunistic Infections↗
PubMed1997

HIV-testing study of immigrants with pulmonary tuberculosis.

The increasing prevalence of tuberculosis (TB) and human immunodeficiency virus (HIV), particularly in Africa and Asia, led us to investigate the prevalence of HIV infection in immigrants with pulmonary TB at the time of arrival in the UK. We performed anonymous HIV testing of stored sera from 39/65 immigrants referred to our unit between January 1991 and December 1994, who had culture-positive pulmonary TB. None of the 39 patients tested was positive for either HIV-1 or HIV-2, and the characteristics of the 26 patients for whom no serum was available were similar to those of the tested group. Despite the need to consider concomitant HIV infection in any patient with TB, particularly those from an area of HIV endemnicity, the present data do not suggest that recently arrived refugees, asylum seekers, immigrants or long-term visitors to the UK constitute a group in whom dual infection of HIV and Mycobacterium tuberculosis is common.

AIDS Serodiagnosis↗
PubMed1996

Visceral leishmaniasis in HIV infected patients: treatment with high dose liposomal amphotericin B (AmBisome).

Visceral leishmaniasis (VL) in patients coinfected with human immunodeficiency virus (HIV) is often atypical, and characteristically relapses after treatment. We treated 10 HIV infected patients (9 men) with parasitologically confirmed VL with liposomal amphotericin B ("AmBisome': L-AMB) at a dose of 4 mg/kg/day on days 1, 2, 3, 4, 5, 10, 17, 24, 31, and 38. Patients were hospitalized for the first 5 days, and were monitored during, and 1 week and 1, 3 and 6 months after, L-AMB therapy. There were no serious adverse events, and L-AMB was well tolerated. 9/10 patients completed therapy, one patient defaulted at day 24. Clinical improvement was seen in all nine patients and the bone marrow aspirate was cleared of visible/culturable parasites in 8/9 patients. During follow-up, one patient defaulted. The seven remaining patients relapsed at 2, 3, 3, 5, 5, 6 and 7 months. Re-treatment with a variety of antileishmanial drugs was unsatisfactory. The time from first diagnosis of VL to death in six patients was 5-40 months (mean 18.8 months). Only one patient remained alive 26 months after treatment. L-AMB is safe and provides a good initial clinical response. Intermittent dosing enables a short period of hospitalization. However, relapse is probably inevitable.

AIDS-Related Opportunistic Infections↗
PubMed1996

Clinical and laboratory features of patients with loiasis (Loa loa filariasis) in the U.K.

To assess differences between Africans and expatriates, we reviewed records of 100 patients with loiasis presenting to The Hospital for Tropical Diseases, London. Fifty-one were black Africans, and 49 were white expatriates. A history of Calabar swellings was more common amongst expatriates (P = 0.0001, OR 8.1), whilst eyeworm was reported more frequently in Africans (P = 0.0038, OR 4.2). Higher eosinophil levels (P < 0.0001) and filarial antibody levels, whether measured by immunofluorescence (P = 0.047) or ELISA (P < 0.0001) were present in the expatriates. Africans were more likely to have microfilaraemia (P < 0.0025, OR 7.3), and among microfilaraemic patients, Africans had denser microfilaraemia (P = 0.012). The sensitivity of microfilaremia as a screening test for loiasis was 75% in Africans and 29% in expatriates. The sensitivities of filarial antibody tests in Africans and expatriates were 81% and 100% for IFAT, and 28% and 93% for ELISA. Following treatment, 63% of patients were considered cured, 25% were lost to follow-up and 12% had a documented relapse. The differences between the two groups of patients could be caused by differences in the chronicity of loiasis, but other explanations are also discussed.

Adolescent↗
PubMed1996

T cell responses to a mixture of Mycobacterium tuberculosis peptides with complementary HLA-DR binding profiles.

The T cell response to a mixture of eight peptides derived from sequences of the Mycobacterium tuberculosis 16-, 19- and 38-kD antigens (MTBmix-8) has been studied. The peptides were selected on the basis of complementary binding to nine HLA-DR molecules (HLA-DR1 to DR9). MTBmix-8 at 6.25 and 50 micrograms/ml gave rise to significant stimulation (P < 0.05) of peripheral blood mononuclear cells (PBMC) from healthy tuberculin-positive and both untreated and treated diseased subjects, but not in any of a control group of healthy tuberculin-negative subjects. MTB-mix-8 stimulated proliferation of PBMC from healthy tuberculin-positive individuals at lower concentrations than the individual component peptides. However, the maximal stimulation achieved was only slightly higher than that achieved with individual peptides. MTBmix-8 also stimulated the production of interferon-gamma (IFN-gamma) in vitro. Using the mean +/- 2 s.d. of the values for IFN-gamma production in the tuberculin-negative population as a cut-off, MTBmix-8 at 6.25 micrograms/ml was able to detect infection with a sensitivity of 100% in untreated patients, 87% in treated patients, and 82% in tuberculin-positive controls. The corresponding figures for the most potent single peptide (16p91-110) were: 66% in untreated patients, 71% in treated patients and only 42% in controls. Thus, using the IFN-gamma-based assay, which has the additional advantages of speed and does not require radioactivity, the mixture of peptides is more sensitive than single peptides in diagnosing infection.

Adult↗
PubMed1996

Short-course treatment of visceral leishmaniasis with liposomal amphotericin B (AmBisome).

We evaluated liposomal amphotericin B (AmBisome; Vestar, San Dimas, CA) administered to 88 immunocompetent patients (56 children) with visceral leishmaniasis (VL) caused by Leishmania infantum. Thirteen patients received 4 mg/kg on days 1-5 and 10 (total dose, 24 mg/kg), and all were cured; 42 received 3 mg/kg on days 1-5 and 10 (18 mg/kg), and 41 were cured; 32 received 3 mg/kg on days 1-4 and 10 (15 mg/kg), and 29 were cured (amastigotes were not cleared from 1 child, and 2 relapsed). One adult was cured with a total dose of 12mg/kg. The four children who were not cured received 3 mg/kg for 10 days; none had further relapses. There were no significant adverse events. For VL due to L. infantum, we recommended a total dose of AmBisome of > or = 20 mg/kg, given in > or = 5 doses of 3-4 mg/kg over > or = 10 days.

Adolescent↗
PubMed1995

Activity of liposomal amphotericin B (AmBisome) in dogs naturally infected with Leishmania infantum.

Thirteen dogs naturally infected with Leishmania infantum showing viscero-cutaneous signs of disease were treated with different dosages of liposomal amphotericin B (AmBisome). The animals were followed clinically and parasitologically over a period of eight months. Dogs which received three to five administrations of AmBisome 3-3.3 mg/kg showed rapid clinical improvement, with regression of lymphadenomegaly and splenomegaly, and cure of skin lesions. The clinical response was similar to that obtained with 14-21 doses of conventional antileishmanial drugs. However, follow-up lymph node aspirates remained positive for Leishmania in all dogs except one, which was treated with the total dose of AmBisome 15 mg/kg. The failure in parasitological cure may be due to inadequate drug targeting to parasitized cells, or to T-cell immune depression characteristic of patent cases of canine leishmaniasis, or to both.

Amphotericin B↗
PubMed1994

Severe falciparum malaria: predicting the effect of exchange transfusion.

The rationale for exchange transfusion (ET) in severe Plasmodium falciparum malaria is to lower the parasite burden rapidly, to replenish unparasitized cells and to correct severe anaemia. In addition, parasite antigens or 'toxins' may be removed. Despite reports of successful ET in the treatment of malaria since 1974, it remains controversial and its role and technique have been poorly defined. We present a mathematical model of ET which relates volume of exchange to reduction in parasitaemia and change in haemoglobin concentration. This model fits published and unpublished clinical data well, and should facilitate standardization of ET in future.

Blood Volume↗
PubMed1994

Liposomal amphotericin B (AmBisome) in Mediterranean visceral leishmaniasis: a multi-centre trial.

Thirty-one patients with visceral leishmaniasis (VL) caused by Leishmania infantum received liposomal amphotericin B (AmBisome) in a multi-centre study. Ten immunocompetent patients (six children) received 1-1.38 mg/kg/day for 21 days, and ten (nine children) received 3 mg/kg/day for 10 days. All were cured without significant adverse events and without relapse during 12-24 months of follow-up. Eleven immunocompromised adults, including seven co-infected with HIV (four with AIDS) received 100 mg (1.38-1.85 mg/kg) daily for 21 days. All were initially considered cured, but eight relapsed clinically and parasitologically at 3-22 months. Liposomal amphotericin B is a new, safe and effective drug for the treatment of VL.

AIDS-Related Opportunistic Infections↗
PubMed1993

Use of ultrasound in a study of schistosomal periportal fibrosis in rural Zimbabwe.

Ultrasound was used to diagnose periportal fibrosis (PPF) in a rural Zimbabwean community where Schistosoma mansoni is endemic. Ultrasound findings were compared with stool microscopy and abdominal palpation in 492 adults (305 females). 47 (9.6%) had definite PPF. The prevalence of PPF increased with age (P < 0.001), while S. mansoni egg counts decreased with age. Even within age groups, egg count did not correlate with PPF. No association was found between lifetime alcohol consumption and the presence of PPF. Splenomegaly and mid-line enlargement of the liver were specific (97% and 94%) but insensitive (21% and 28%) markers for PPF. Spleen size varied with S. mansoni egg count independently of the presence or degree of PPF. Endoscopy of 18 patients with PPF revealed oesophageal varices in two, both of whom had severe PPF.

Abdomen↗