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Biomedical subjects

S B Lucas

Publications and source records attributed to S B Lucas.

At least 73 records · Page 4Linked to original sources
PubMed1995

Immunohistochemical study of cutaneous neuritis in positive lepromin reactions.

Sixty skin biopsies taken from positive tuberculoid and borderline-tuberculoid late lepromin reaction were studied using histological techniques. The distribution of mycobacterial antigen and nerves was demonstrated using immunochemical methods. A total of 557 nerve bundles was observed in 51 biopsies; 9 were devoid of nerves in the sections examined; 475 nerve bundles showed some relationship to the inflammatory infiltrate (85%); perineuritis being seen in 144 (30%) and endoneuritis in 5 (0.9%). Mycobacterial antigens inside the granuloma were detected in 59 of the 60 biopsies (98%). Only one specimen, showing a strong tuberculoid reaction, failed to show these antigens. On the contrary, mycobacterial antigen was absent in almost all nerves. Small deposits were detected in the perineurium of one nerve with perineuritis, and inside a Schwann cell of another, the latter belonging to a previously multibacillary patient. The neurotropic tendency of the granuloma does not seem to be stimulated by the presence of mycobacterial antigens inside the nerves, as normally these antigens do not penetrate them. The hypothesis of some antigenic fraction of the neural tissue which cross-reacts with Mycobacterium leprae antigens, thus eliciting a perineural or near-perineural inflammatory reaction is put forward, but needs further investigation.

Antigens, Bacterial↗
PubMed1995

Clinical and histological discrepancies in diagnosis of ENL reactions classified by assessment of acute phase proteins SAA and CRP.

Sixteen out of 45 (36%) leprosy patients with clinical features of acute erythema nodosum leprosum (ENL) did not show the characteristic presence of neutrophils (polymorphs) in histology of the ENL lesion. The acute-phase reactants, serum amyloid A (SAA) and C-reactive protein (CRP) which are systemic markers of inflammation, and IgM and IgG antibody to Mycobacterium leprae were determined in these patients in order to understand the differences in histological diagnosis. Both SAA and CRP were elevated in ENL patients, irrespective of the presence of polymorph infiltrates, as compared to nonreactional lepromatous patients, patients with histologically confirmed reversal reactions and endemic controls, indicating that all clinically diagnosed ENL patients had ongoing inflammatory reactions. On the other hand, IgM and IgG antibodies were significantly lower (> 70%) in ENL patients as compared to nonreactional lepromatous patients. When the two ENL groups [ENL-PMN+ve (positive for neutrophils) and ENL-PMN-ve (negative for neutrophils)] were compared, there were no significant differences in the mean SAA, IgM or IgG antibody concentrations, but CRP was eightfold lower in ENL-PMN-ve as compared to the ENL-PMN+ve group. This may indicate that the timing or modulation of the reaction was different in the two ENL groups. Thus, measurement of the acute-phase response and the ratio of SAA/CRP in particular are helpful in the clinical diagnosis of ENL reactions in leprosy.

Adolescent↗
PubMed1994

HIV-associated lymphoma in Africa: an autopsy study in Cote d'Ivoire.

HIV infection predisposes to the development of non-Hodgkin lymphoma (NHL). The frequency of NHL among HIV-positive adults and children in sub-Saharan Africa is not known. In 1991-1992, a representative autopsy study of HIV infection was performed in Abidjan, Côte d'Ivoire. Of 247 HIV-positive adult (> 14 years) medical patients dying in hospital, 2.8% had NHL, 1.6% with visceral NHL and 1.2% with primary cerebral lymphoma. The estimated crude incidence of NHL among HIV-positive adults in Abidjan was 84/100,000 per year, 10-fold greater than the expected pre-AIDS incidence of NHL but less than the incidence observed among HIV-positive adults in industrialised countries. None of 78 autopsied HIV-positive children (median age = 17 months) had NHL. HIV infection augments the incidence of NHL among adults in Africa, but short survival with advanced HIV disease probably prevents the major increase in HIV-associated NHL seen in industrialised countries. Survival of HIV-positive children in Africa appears too short to permit the significant development of additional NHL; classic Burkitt lymphoma is not an AIDS-associated tumour in Africa.

Adolescent↗
PubMed1994

Contribution of tuberculosis to slim disease in Africa.

OBJECTIVES: To assess the contribution of tuberculosis to the aetiology of the HIV wasting syndrome (slim) in Africa, a condition usually considered an enteropathy. METHODS: Clinical examination and representative necropsy study of adult patients positive for HIV. SETTING: Hospital medical wards in Abidjan, Ivory Coast. SUBJECTS: Adults positive for HIV. MAIN OUTCOME MEASURES: CD4 T lymphocyte counts before death, clinical and anthropometric data, and gross and microscopic pathology. RESULTS: Necropsy was done on 212 HIV positive adults. Tuberculosis was found in 41 of 93 with the clinical HIV wasting syndrome and in 32 of 119 without (odds ratio 2.1, 95% confidence interval 1.2 to 4.0). A significant association existed between the prevalence of tuberculosis at necropsy and the degree of cadaveric wasting (no wasting 25% (15/59); moderate wasting 40% (23/58); skeletal wasting 44% (42/95); P = 0.02). Wasting was also associated with a history of chronic diarrhoea, but no association existed between diarrhoea and tuberculosis. Median CD4 T lymphocyte counts were lowest in wasted patients irrespective of findings at necropsy and in those with chronic diarrhoea (< 60 x 10(6)/l). CONCLUSION: Wasting and chronic diarrhoea are late stage manifestations of HIV disease in Africa. The importance of tuberculosis as a contributing factor in the pathogenesis of the slim syndrome has been underestimated. In nearly half of patients dying with severe wasting, tuberculosis was the dominant pathological finding.

Adolescent↗
PubMed1994

Helicobacter pylori infection and gastritis in healthy Nigerians.

In a study of forty asymptomatic volunteers from northern Nigeria; 35 (87.5%) had histological gastritis and 32 (80%) were infected by Helicobacter pylori. All but one of the patients infected by Helicobacter Pylori had histological gastritis. This high prevalence of H. Pylori infection in young, asymptomatic subjects, occurs in an area with a low prevalence of duodenal ulcer. The possible reasons for this are discussed.

Adolescent↗
PubMed1994

Nocardiosis in HIV-positive patients: an autopsy study in West Africa.

BACKGROUND: There are many reports of nocardiosis associated with HIV infection in industrialized and developing countries, but its true prevalence is unknown. MATERIALS AND METHODS: An autopsy study was performed of HIV-positive and HIV-negative patients dying on the general medical wards of a large hospital in Abidjan, Ivory Coast, in 1991. RESULTS: 247 HIV-positive adult cadavers were examined. 10 (4%) had nocardiosis of the lung, of whom 6 showed disseminated disease. 8 patients had one or more AIDS-defining pathologies, and 5 had nocardiosis as the main cause of death. Pulmonary tuberculosis was found in 87 cadavers (35%), giving a ratio of pulmonary nocardial to tuberculous disease of 1:9. No nocardiosis was seen in 42 HIV-negative cadavers. CONCLUSIONS: This is the highest recorded prevalence of HIV-associated nocardiosis in a representative sample. The prevalence of nocardiosis varies geographically, and in zones where HIV-associated tuberculosis is common, it is possible that some patients diagnosed as smear-negative pulmonary tuberculosis actually have nocardiosis. A revised strategy of sputum examination with gram stain is suggested to detect nocardia.

AIDS-Related Opportunistic Infections↗
PubMed1994

Reactions in leprosy: an epidemiological study of 386 patients in west Nepal.

This paper presents epidemiological data on reversal reaction (RR) and erythema nodosum leprosum reaction (ENL) from a retrospective study of 386 leprosy patients newly registered at Green Pastures Hospital, Pokhara, West Nepal. The average follow-up time was 21 months. The prevalence of RR at first examination was 28% (23-32), and the prevalence of ENL reaction was 5.7% (2.3-9.2). The overall incidence rates among the 335 patients that were available for follow-up were 8.7 (6.5-12)/100 person years at risk (PYAR) for RR and 3.2 (1.5-6.7)/100 PYAR for ENL. Relapse of RR was common (1.4/patient). In all, 52% of RR were complicated by new nerve function impairment, against 59% of ENL reactions. The finding of other investigators that most RRs occur during the first year of treatment was confirmed by this study. The most significant risk factor for RR was extent of clinical disease measured by a count of body areas with clinical signs of leprosy. The risk of developing a RR for patients with 'extensive disease' (3 or more out of 9 body areas involved) was 10 times that of patients with limited disease (Rate Ratio 10 (1.3-76), p = 0.026). The study indicated that the following categories of patients in Nepal are at high or increased risk of developing a RR: 1, borderline patients during their first year of MDT; and 2, patients with more extensive clinical disease as described above.

Adolescent↗
PubMed1993

Use of polymerase chain reaction to assess efficacy of leprosy chemotherapy.

The assessment of chemotherapy efficacy in leprosy is difficult, since the only reliable method for determining whether the causative organism, Mycobacterium leprae, is viable depends on its growth in mouse foot pads. In an attempt to replace this expensive, time-consuming test, methods based on the polymerase chain reaction (PCR) have been developed. These methods depend on detection of DNA, which is more susceptible to degradation on cell death than are other cell components, so should be a more accurate indicator of viability. We have used a specific PCR assay to detect M leprae DNA in skin biopsy samples from leprosy patients. By use of limiting dilution PCR (LD-PCR), the concentration of M leprae DNA in the original sample could be measured. The DNA concentration was more closely correlated with the morphological index (derived from a staining technique that distinguishes morphologically intact and damaged bacteria) than with the number of bacteria visible (bacterial index, BI, which counts both alive and dead bacteria). In a longitudinal study of multibacillary patients on multi-drug therapy, skin biopsy samples were collected before treatment and 3, 6, 12, and 24 months after the start of therapy. While the BI showed little or no change during treatment, the number of genomes detected by PCR fell sharply, in parallel with the MI. We propose that PCR can be used as a rapid measure of M leprae viability and that this approach can be used for monitoring individual leprosy patients and for assessment of existing and new regimens. The method may be applicable to other infectious diseases in which culture of the causative organism is slow or impossible.

Base Sequence↗
PubMed1993

A case control study on human immunodeficiency virus-1 (HIV-1) infection as a risk factor for tuberculosis and leprosy in western Kenya.

A case control study was undertaken in Western Kenya from April 1989 to August 1990 to evaluate HIV-1 infection as a risk factor for tuberculosis and leprosy. The study involved 144 newly diagnosed sputum smear positive tuberculosis cases with 432 age, sex and neighbourhood-matched controls, and 132 diagnosed leprosy cases with 384 matched controls. Odds ratios obtained by conditional logistic regression (matched) analysis were 4.9 (95% CI 2.6, 6.8), and 1.8 (95% CI 0.9, 3.2), for the association between HIV-1 and tuberculosis and leprosy respectively. Approximately 31% of tuberculosis cases among males, and 11% of cases among females, were attributable to HIV infection.

AIDS-Related Opportunistic Infections↗
PubMed1993

Pathogens and predictors of fatal septicemia associated with human immunodeficiency virus infection in Ivory Coast, west Africa.

In East Africa, bacteremia is more common in hospitalized human immunodeficiency virus (HIV) type 1-positive than -negative patients. In 1991, blood cultures and clinical and laboratory data were obtained from 319 patients in Ivory Coast, where both HIV-1 and -2 infections occur. Forty-three bacterial, 10 mycobacterial, and 8 fungal pathogens were isolated from blood of 54 patients (17%). Pathogens isolated significantly (P < or = .05) more frequently from HIV-positive than -negative patients were nonmycobacterial bacteria, particularly Salmonella enteritidis; mycobacteria, particularly Mycobacterium tuberculosis-Mycobacterium bovis; and yeast or fungus. HIV-1 or -2 positivity was associated with a 3-fold increased risk for septicemia (P < .02). HIV-positive patients with fever or with lymphocyte counts < 1000 were more likely to be septicemic than those without these characteristics. Mortality increased significantly with HIV positivity (40% vs. 14%, P < .001) and, among HIV-positive patients, with having pathogens isolated from blood (63% vs. 33%, P < .001).

Adult↗
PubMed1993

The mortality and pathology of HIV infection in a west African city.

BACKGROUND: HIV disease is epidemic in Africa, but associated mortality, underlying pathology and CD4+ T-lymphocyte counts have not previously been evaluated in a representative study. Such data help to determine the management of HIV-positive people. Both HIV-1 and HIV-2 infections are prevalent in Côte d'Ivoire, and the pathology of HIV-2 infection in Africa is unclear. METHODS: Consecutive adult medical admissions to a large city hospital in Côte d'Ivoire were studied in 1991, and a sample of HIV-positive deaths autopsied. RESULTS: Of 5401 patients evaluated, 50% were HIV-positive; 38% of these died, with a median survival of 1 week. At autopsy (n = 294, including 24% of HIV-positive deaths in hospital), tuberculosis (TB), bacteraemia (predominantly Gram-negative rods) and cerebral toxoplasmosis caused 53% of deaths. TB was seen in 54% of cadavers with AIDS-defining pathology and Pneumocystis pneumonia in 4%. The median CD4+ T-lymphocyte counts in those who died was < 90 x 10(6)/l. Compared with HIV-1-positives, patients with HIV-2-positivity had a greater frequency of severe cytomegalovirus infection, HIV encephalitis and cholangitis. CONCLUSIONS: In this population, HIV-positive adults present to hospital with advanced disease associated with high mortality. The three major underlying pathologies (TB, toxoplasmosis and bacteraemia) are either preventable or treatable. TB is an underestimated cause of the 'slim' syndrome in Africa. The patterns of pathology in HIV-2-positive patients suggest a more prolonged terminal course compared with HIV-1. There is an urgent need for attention towards the issues of therapy and care for HIV disease in developing countries.

AIDS-Related Opportunistic Infections↗
PubMed1993

HIV and the necropsy.

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AIDS-Related Opportunistic Infections↗
PubMed1993

Clinical research, prophylaxis, therapy, and care for HIV disease in Africa.

By the end of the century, citizens of resource-poor countries will constitute 90% of the world's human immunodeficiency virus (HIV)-infected people. Clinical management of such persons in developing countries has been neglected; most AIDS research has concentrated on epidemiology, and donor agencies have generally invested in the prevention of HIV infection. The heavy burden of HIV disease in Africa requires that care for AIDS be addressed, and prevention and care should be seen as interrelated. Prevention and treatment of tuberculosis, the commonest severe infection in persons with AIDS in Africa, illustrate this interrelationship. We outline priorities for applied research on the management of HIV disease in a resource-poor environment, and discuss prophylaxis, therapy for opportunistic diseases, terminal care, and use of antiretroviral therapy. Research should define the standard of care that can realistically be demanded for HIV disease in a resource-poor environment. Research and public health programs for AIDS in developing countries must address AIDS care and attempt to reduce the widening gap between interventions available for HIV-infected persons in different parts of the world.

AIDS-Related Opportunistic Infections↗