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Biomedical subjects

R N Davidson

Publications and source records attributed to R N Davidson.

At least 55 records · Page 3Linked to original sources
PubMed1993

Epidemic visceral leishmaniasis in Sudan: a randomized trial of aminosidine plus sodium stibogluconate versus sodium stibogluconate alone.

In a comparative trial of treatment in southern Sudan, visceral leishmaniasis was diagnosed by the following symptoms: fever for > 1 month, splenomegaly, and antileishmanial direct agglutination test (DAT) titer of > or = 1:25,600. Patients (200) were randomized to receive sodium stibogluconate (Sbv) at 20 mg/kg/day for 30 days (groups S, n = 99) or Sbv at 20 mg/kg/day plus aminosidine at 15 mg/kg/day for 17 days (group AS, n = 101). Of 192 patients who had spleens or lymph nodes aspirated at entry, 134 (70%) were positive for parasites. During treatment, 7% in group S and 4% in group AS died. All 184 patients who completed treatment were clinically cured. At days 15-17, microscopy of aspirates showed that 57 (95%) of 60 in group AS were negative for parasites compared with 47 (81%) of 58 in group S (P = .018). At day 30, 57 (93.4%) of 61 group S aspirates were negative.

Adolescent↗
PubMed1993

Activity of liposomal amphotericin B (AmBisome) against Leishmania infantum and tissue distribution in mice.

Preliminary observations have shown that AmBisome, a liposomal formulation of amphotericin B (Vestar Inc.), is effective and non-toxic in animal and human visceral leishmaniasis. The activity of multiple doses of this drug on Leishmania infantum, in BALB/c mice was investigated, and amphotericin B concentration in liver and spleen was determined. Groups of infected mice were treated intravenously with 3, 5, or 7 doses of AmBisome (3 mg/kg) over 3, 10 and 25 days, respectively. The antileishmanial activity of the drug was compared with that of meglumine antimoniate (28 mg Sbv/kg per day over 21 days). Three consecutive daily doses of AmBisome were sufficient to clear all parasites from the liver of mice, while antimony did so only after 21 doses. Twenty-four-48 h after their last dose all the AmBisome-treated mice showed very high amphotericin B concentrations in liver (61.2-76.2 micrograms/g) and spleen (39.8-72.1 micrograms/g) with no overt signs of toxicity. Mice that received 2 or 4 doses at intervals of 5 to 8 days, maintained drug levels as high as those detected after 3 consecutive doses over 11 and 26 days, respectively. This should enable visceral leishmaniasis treatment on an intermittent or outpatient basis, thereby reducing overall treatment costs.

Amphotericin B↗
PubMed1992

Severity of imported falciparum malaria: effect of taking antimalarial prophylaxis.

OBJECTIVE: To investigate the effects of antimalarial chemoprophylaxis and other variables on the severity of falciparum malaria. DESIGN: Review of consecutive malaria cases between 1987 and 1991. SETTING: The Hospital for Tropical Diseases, London. SUBJECTS: 250 consecutive cases of mild and 51 consecutive cases of severe falciparum malaria. RESULTS: Prophylaxis was taken in 52.4% (131/250) of the cases of mild malaria and 21.6% (11/51) of cases of severe malaria. Severe malaria was more common in white patients than in those of African origin and was also seen more commonly in people returning from central, southern, and east Africa than in those returning from west Africa. Patients with severe malaria presented sooner than patients with mild malaria. CONCLUSIONS: Prior chemoprophylaxis led to a reduction in the severity of falciparum malaria. Ethnic origin, time to presentation, and sex were also associated with the severity of malaria.

Adult↗
PubMed1991

Liposomal amphotericin B in drug-resistant visceral leishmaniasis.

The treatment of visceral leishmaniasis (VL) may be complicated by drug toxicity or intolerance, and by drug resistance. Amphotericin B (AmB) is effective, but its use is limited by toxicity: renal impairment, anaemia, fever, malaise, and hypokalaemia are common. Liposomes have been proposed as an effective way to target drugs at macrophages, which are the cells infected in visceral leishmaniasis. In animals AmB incorporated into liposomes is highly effective against experimental leishmaniasis, with low toxicity. This report is of the successful treatment of a patient with multiply drug-resistant visceral leishmaniasis with a commercially prepared formulation of liposomal amphotericin B (L-AmB) ('AmBisome', Vestar, San Dimas, California, USA). We also report, for comparison, a patient treated with conventional AmB, and preliminary studies in mice comparing the two agents.

Amphotericin B↗
PubMed1991

Liposomal amphotericin B in the treatment of visceral leishmaniasis.

A case of visceral leishmaniasis unresponsive to several course of treatment with standard drugs, was successfully cured by a 21 day course (50 mg/day) of liposomal amphotericin B (AmBisome, Vestar Inc.). The efficacy of the AmBisome formulation is supported by experimental studies on Leishmania donovani infected BALB/c mice where ED50 values of AmBisome and conventional amphotericin B were 0.15-0.25 and 0.95-4.9 mg/kg, respectively. A lack of toxicity of the AmBisome formulation was noted in both studies.

Adult↗
PubMed1991

Diagnosing multiple parasitic infections: trypanosomiasis, loiasis and schistosomiasis in a single case.

A case is reported of a 32-year-old traveller with loiasis, schistosomiasis and African trypanosomiasis. The patient had been working in oil exploration in Nigeria and Gabon and presented with Calabar swellings and carpal tunnel syndrome. Serology for all 3 diseases was positive but microfilariae of Loa loa and ova of schistosomiasis were not found. Treatment with diethylcarbamazine and praziquantel was given for loiasis and schistosomiasis respectively. Trypanosomes were isolated from a lymph node aspirate only after repetition of the procedure 2 months later and the patient was treated with suramin. He developed a drug induced nephritis and was then treated successfully with alpha-difluoromethylornithine. There is a discussion of the difficulties encountered making these diagnoses in Europeans particularly where there are atypical clinical features. The risks of rural work in West Africa are noted and the importance of considering all parasitic diseases relevant to the travel/occupational history is emphasised.

Adult↗
PubMed1990

Therapeutics review: the use of parenteral drugs for falciparum malaria.

Recent studies on the pharmacokinetics of parenteral chloroquine and quinine have resulted in safer regimens for the treatment of severe falciparum malaria. In this article we summarise these regimens, and discuss the emergence of chloroquine resistance and the implications for treatment.

Animals↗
PubMed1989

Fibreoptic bronchoscopy: an assessment of immediate cytological diagnosis using methylene blue stain.

A method of examining cytological material during fibreoptic bronchoscopy using a methylene blue (MB) stain was assessed in 164 consecutive fibreoptic bronchoscopies where cytology specimens were taken. The MB method provided an immediate positive diagnosis in 86% of bronchoscopically visible tumours. Subsequent histology provided a positive diagnosis in 69%, conventional brush cytology in 81% and trap cytology in 77%. The MB method produced no false positive diagnosis of malignancy and the tumour cell type identified by MB stain agreed with the histological cell type in 72% of cases. This technique is considered to be sufficiently specific to provide a method of controlling the quality of specimens taken at bronchoscopy, for further analysis in the laboratory.

Bronchial Neoplasms↗
PubMed1988

Group G streptococcal endocarditis: two case reports, a review of the literature and recommendations for treatment.

Two cases of endocarditis caused by a group G streptococcus are reported and the literature on group G streptococcal endocarditis is reviewed. The onset of illness is usually acute and the portal of entry for the organism through the skin. The left side of the heart is mainly involved and in about 50% cases the endocarditis arises on a normal valve. Most patients develop complications, both embolic and cardiac, and the mortality is high (36%). We suggest that patients with proven group G streptococcal endocarditis should be treated with large doses of benzyl penicillin and with an aminoglycoside for not less than 4 weeks. Patients with complications should be referred to a cardiothoracic centre. We should be glad to know details of complications, treatment and outcome in other cases of group G streptococcal endocarditis.

Acute Disease↗
PubMed1988

Craniofacial resection for extensive paranasal sinus aspergilloma.

Craniofacial resection techniques were developed to allow complete monobloc removal of malignant tumours of the ethmoid region. Such a surgical approach may also occasionally be useful in certain non-malignant conditions. Extensive 'destructive' aspergillosis of the paranasal sinuses has a high mortality once the anterior cranial fossa dura is reached. Craniofacial surgery provides excellent access to excise such large infective 'tumours'.

Adolescent↗
PubMed1988

Chickenpox pneumonia: experience with antiviral treatment.

Of 13 patients with chickenpox pneumonia (12 of them adults) treated during 1979-87, 10 received antiviral drugs--nine acyclovir and one vidarabine. Three died despite intensive treatment. Serious secondary infections occurred in six cases. There were no clear indications that antiviral treatment altered the natural history of the condition. Acyclovir may at present be used too late in the course of chickenpox pneumonia to alter its outcome.

Acyclovir↗