PubMed Health⌕ Search

Biomedical subjects

R Butlin

Publications and source records attributed to R Butlin.

9 recordsLinked to original sources
PubMed2001

Sexual selection and speciation.

The power of sexual selection to drive changes in mate recognition traits gives it the potential to be a potent force in speciation. Much of the evidence to support this possibility comes from comparative studies that examine differences in the number of species between clades that apparently differ in the intensity of sexual selection. We argue that more detailed studies are needed, examining extinction rates and other sources of variation in species richness. Typically, investigations of extant natural populations have been too indirect to convincingly conclude speciation by sexual selection. Recent empirical work, however, is beginning to take a more direct approach and rule out confounding variables.

Journal Article↗
PubMed2000

Delay in presentation and start of treatment in leprosy: experience in an out-patient clinic in Nepal.

Delayed presentation is a recognized risk factor for disability in leprosy but is the result of complex interactions between physical, social, economic and psychological factors. The present study is a response to the situation in an outpatient clinic in Nepal where the wide variation in delay in presentation was a cause for concern. A purpose-written questionnaire was used to collect information on 166 consecutive outpatient admissions. The data included demographics, the first symptom of leprosy, first actions, initial help-seeking behaviour, the reasons for finally seeking treatment and experience with professional health services. Initial analysis found a relationship between delay in presentation and age, rural environment, leprosy classification, walking time, housing not shared with another person affected by leprosy, and an inappropriate first action. The relationship with lack of education and total travel time just failed to reach significance. Further analysis identified that for the study population initial lack of awareness of leprosy and an inappropriate first action were the primary contributors to delay. Extensive and effective health education is needed to address this situation.

Adolescent↗
PubMed1993

Lymphocyte proliferation, IFN-gamma production and limiting dilution analysis of T-cell responses to ICRC and Mycobacterium leprae antigens in leprosy patients.

Lymphocyte proliferative responses and interferon-gamma (IFN-gamma) production after stimulation with antigens of ICRC, Mycobacterium leprae, and purified protein derivative (PPD) were assessed in leprosy patients and healthy donors. The patients studied were newly diagnosed as having lepromatous leprosy (LL), multidrug therapy (MDT) responders (MDT-R LL), MDT nonresponders (MDT-NR LL), borderline lepromatous (BL), and borderline tuberculoid/tuberculoid (BT/TT) leprosy. The tuberculoid leprosy patients showed increased lymphocyte proliferation and IFN-gamma production in response to stimulation with ICRC, M. leprae, and PPD antigens compared to other groups of LL patients and healthy donors. Although lymphocytes from LL patients showed low responses to ICRC and M. leprae antigens, their responses to PPD were not grossly affected. MDT-R LL patients showed higher lymphocyte proliferative responses and IFN-gamma production after stimulation with ICRC and PPD but not with M. leprae antigens. Tuberculoid leprosy patients showed higher T-cell frequencies to ICRC and M. leprae antigens compared to MDT-R LL and MDT-NR LL patients. The increased lymphocyte proliferative responses to ICRC observed in the MDT-R LL patients was reflected in the increased T-cell frequency to ICRC compared to M. leprae.

Antigens, Bacterial↗
PubMed1992

Major proteins of mycobacterial strain ICRC and Mycobacterium leprae, identified by antibodies in sera from leprosy patients and their contacts.

Sera from leprosy patients across the clinical spectrum, healthy contacts, tuberculosis patients, and healthy donors were tested for their reactivity with antigens of mycobacterial strain ICRC (a cultivable mycobacterium) and Mycobacterium leprae by immunoprecipitation technique. Using M. leprae antigens, it was not possible to distinguish between reactivities of sera from lepromatous, borderline lepromatous, borderline tuberculoid, and tuberculoid leprosy patients. All these sera identified M. antigens with molecular masses of 47, 36, 21, and 14 kDa. When the same sera were tested for their reactivities with antigens of mycobacterial strain ICRC, several differences were observed. The 21-kDa antigen of mycobacterial strain ICRC was exclusively precipitated by sera from all lepromatous leprosy patients and from those undergoing erythema nodosum leprosum reaction. Sera from all the other donors tested failed to identify the 21-kDa antigen of mycobacterial strain ICRC. The 14-kDa protein of mycobacterial strain ICRC was identified by sera from a few lepromatous leprosy patients (5 of 26) and all their contacts. Our studies indicate that antigens present on cultivable mycobacteria rather than species-specific antigens may prove to be useful in the serodiagnosis of leprosy.

Antibodies, Bacterial↗
PubMed1991

Mitogen induced proliferation and cytokine production by lymphocytes from leprosy patients.

In this paper we have assessed the mitogen responses of leprosy patients and healthy donors in terms of proliferation and cytokine production (Interleukin 2 and Interferon gamma). The patients investigated included untreated and multidrug therapy non-responsive LL patients and MDT responsive LL and TT patients. The mitogen responses of untreated and multidrug therapy non responsive LL patients were not significantly different from those of the healthy donors. It was interesting to note that TT and multidrug therapy responsive LL patients showed higher responses to mitogens than healthy donors as assessed by all three parameters. The results suggest a correlation of increased mitogenic responses with improvement in clinical status in leprosy.

Cell Division↗
PubMed1990

Natural killer-cell-mediated and antibody-dependent cellular cytotoxicity in leprosy.

We have assessed the natural killer (NK) cell-mediated cytotoxicity and antibody-dependent cellular cytotoxicity (ADCC) in the peripheral blood lymphocytes (PBL) from untreated lepromatous leprosy (LL) patients, LL patients on multidrug therapy (MDT) with favorable responses (MDT-R), LL patients clinically classified as nonresponders to MDT (MDT-NR), treated tuberculoid leprosy (TT) patients, and healthy donors. NK cytotoxicity was modulated by treating the PBL with recombinant interferon-alpha (IFN-alpha) and recombinant interleukin-2 (IL-2). The mean percent NK cytotoxicity of untreated LL patients (15 +/- 3), treated MDT-R patients (20 +/- 4), and treated MDT-NR patients (12 +/- 4) was significantly lower than that of TT patients (39 +/- 6) and healthy donors (37 +/- 5). Treatment of effectors with IL-2 or IFN-alpha enhanced NK cytotoxicity in 5 of 6 untreated LL patients, 6 of 6 treated MDT-R LL patients, 4 of 5 and 3 of 5 treated MDT-NR LL patients, respectively, and 5 of 8 and 3 of 8 treated TT patients, respectively. Although PBL from TT patients showed initial NK activity comparable to that of healthy donors, fewer TT patients showed modulation of NK activity by IL-2, and IFN-alpha to a lesser extent. The ADCC activity was lower in untreated LL patients compared to treated patients, while TT patients had normal ADCC activity. The results indicate that although LL patients show lowered spontaneous cytotoxicity, it can be modulated favorably by lymphokines.

Antibody-Dependent Cell Cytotoxicity↗