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Biomedical subjects

K Katoch

Publications and source records attributed to K Katoch.

At least 73 records · Page 4Linked to original sources

Comparative study on the thin-layer chromatographic pattern of methyl mycolates of M. leprae and related species.

The thin-layer chromatographic (TLC) pattern of methyl mycolates of Mycobacterium leprae has been compared with the lipids extracted from M. leprae-infected tissue material and also with those of other cultivable mycobacterial species. It has been found that M. leprae-derived methyl mycolates give two spots, namely, alpha- and keto-derivatives, after charring the TLC plates with K2Cr2O7/H2SO4 spray. Lipids extracted from infected tissue material also show spots with the same Rf values when compared with those of armadillo-derived M. leprae. Normal skin tissue extracts, however, do not show any presence of mycolates. This TLC pattern of M. leprae-derived methyl mycolates is characteristic and is not shown by any other mycobacterial species isolated from leprosy lesions. The strain and species which have been earlier found to resemble M. leprae antigenically or biochemically could readily be distinguished with the help of the TLC pattern of their methyl mycolates.

Cell Wall↗

Hepatitis-B virus infection in patients with leprosy--a brief communication.

The prevalence rate of hepatitis-B surface antigen (HBsAg) were determined in 413 patients of different types of leprosy and 133 healthy controls from the same population, in a study undertaken over a period of more than 3 years. The average frequency of australia antigen (HBsAg) was 7.7% in leprosy cases as compared to 6.0% in their healthy counterparts. Across the spectrum 7.2% of lepromatous patients (LL); 8.5% of borderline lepromatous (BL); 9.1% of borderline borderline (BB); 8.6% of borderline tuberculoid (BT) and 8.8% of tuberculoid (TT) cases were positive for HBsAg. Though the prevalence of australia antigen was slightly higher in borderline tuberculoid, borderline borderline and tuberculoid cases, it is not statistically significant. No association between carriership of HBsAg and lepromatous leprosy could be found in the present study.

Adult↗

Solid, fragmented and granular index as one of the parameters in drug trials.

A bacteriological study of the skin smears of 108 bacteriologically positive cases of leprosy, 30 of them untreated, has been undertaken. In each case solid, fragmented and granular (SFG) index, bacteriological index (BI) and morphological index (MI) of skin smears from 4 sites were calculated. The results show that SFG index together with BI can be used as one of the parameters in drug trials. The importance of SFG index in research and as a routine laboratory procedure in leprosy control units undertaking multi drug therapy is discussed.

Clinical Trials as Topic↗

Indirect assay of beta hydroxy beta methyl glutaryl CoA reductase in the sera of leprosy patients--a further probe into cholesterol metabolism.

With an aim to study the cholesterol biosynthetic capacity of the leprosy patients, the enzyme Beta hydroxy methyl glutaryl CoA reductase (HMG CoA) has been indirectly determined in the sera of leprosy patients and their family members by assaying the circulating levels of HMG CoA and mevalonate and finding out the ratio between two. The ratio was around 1 in leprosy patients indicating a normal HMG CoA reductase activity and approximately the same values were obtained in cases of healthy controls. The results suggest that cholesterol biosynthetic capacity of leprosy patients is normal. Whether cholesterol, the final product or intermediates like mevalonate are utilised by the invading M. leprae, thereby causing a lowered cholesterol level remains to be seen.

Cholesterol↗

Study of gene probes in childhood leprosy.

The objective was to detect nucleic acids of M. leprae in skin lesions of leprosy patients and study the effect of treatment on these nucleic acids, using r-RNA gene probes, using a cross sectional study. The study was carried out at Department of Paediatrics, S.N. Medical College, Agra and Department of Microbiology, Central JALMA Institute for leprosy, Agra. The study included 32 cases of leprosy less than 16 years of age, divided into 3 groups viz. without treatment (12 cases), in middle of treatment (11 cases) and at the end of treatment (9 cases). All cases were subjected to a detailed history and thorough clinical examination. All of them had smear examination and lepromin test done and their skin biopsies were subjected to gene detection. Nucleic acids were isolated from skin biopsies of all cases by standard procedure. After dot blotting of these nucleic acids, they were hybridised with radioactive (p32) r-RNA probes. The results were interpreted after getting the X-ray films processed with background signals from controls. Majority of cases were between 13-16 years of age. As age advanced, the disease moved from tuberculoid end of spectrum towards lepromatous end (p < 0.05). Majority of paucibacillary (PB) cases were lepromin positive while majority of multibacillary (MB) cases were lepromin negative (p < 0.05). In specimens of untreated cases, 50% of PB specimens and 87.5% of MB specimens were positive for r-RNA probes. In multibacillary type 100% smear positive specimens and 67% smear negative specimens were positive for r-RNA probes. In patients during the middle of treatment positivity for r-RNA decreased and 20% of PB specimens and 16.6% MB specimens were positive. At the end of treatment (1 year for PB cases and 2 years for MB cases), the results of r-RNA were negative, which indicated that the treatment regimens used in the study were effective. This study supports the usefulness of r-RNA probes as a diagnostic and therapeutic tool in childhood leprosy.

Adolescent↗

Chemotherapy trial in paucibacillary leprosy using clofazimine.

In a double blind study, 300 PB patients (smear negative, indeterminate, tuberculoid and borderline tuberculoid) were randomly allotted to two regimens, the control subjects (150 patients) receiving the standard WHO multidrug regimen of six doses of once a month rifampicin with daily dapsone therapy for six months, while the study group (150 patients) receiving 50 mg of clofazimine daily for six months in addition to the WHO regimen. After stoppage of therapy all the patients were followed up on placebo. The regimens were well tolerated. In 7.5% of patients on clofazimine containing regimen, the lesions showed persisting activity at the time of stoppage of therapy, compared with 16% on the control regimen. This activity subsided spontaneously, more rapidly, in the study group (80% compared with 30% in the control group) in six months. Two patients in the control group and one patient in the study group developed late reaction. There were no relapses in the study group, whereas, two patients have relapsed in the control group during a follow-up of 2.5 to 3.5 years.

Clofazimine↗

Assessment of viability by normal mouse foot-pad and bacillary ATP bioluminescence assay in multibacillary cases treated with an MDT regimen using conventional as well as newer drugs like minocycline and ofloxacin.

The therapeutic effect of a drug regimen of conventional drugs as well as newer drugs like ofloxacin and minocycline in smear-positive multibacillary (MB) leprosy cases was assessed by mouse foot-pad and ATP bioluminiscence methods. Biopsies were taken before starting treatment and after one year of treatment. They were processed for viability assessment by normal mouse foot-pad inoculation and bacillary ATP assay techniques. The test regimen was quite effective in its anti-bacterial effect as it was found to result in loss of bacillary viability in all the cases, as assessed by both methods.

Adenosine Triphosphate↗

Patients presenting with defined areas of sensory loss--a preliminary study.

Thirty patients presenting with circumscribed areas of clearly demonstrable hypoesthesia were chosen from amongst those attending this Institute. Their history and clinical features were recorded, lepromin test was done for reading at four weeks, and peripheral part of the hypoesthetic area was biopsied for histopathology and immunostaining. The subjects were predominantly adult males with the symptomatic sites limited to the extremities. On routine histopathological examination of the symptomatic sites, the diagnosis of leprosy, using defined criteria, could be made in six cases (20%). Immunostaining of the remaining sections showing either no pathology or a nonspecific pathology revealed the presence of mycobacterial antigen in five of the 24 cases (20.83%). Overall, leprosy could be diagnosed in 11 of the 30 cases studied (36.66%). This study shows that leprosy may be an important cause of circumscribed areas of sensory deficit.

Adolescent↗

Treatment of paucibacillary leprosy with a regimen containing rifampicin, dapsone and prothionamide.

Ninety paucibacillary leprosy patients having indeterminate (I), tuberculoid (TT) and borderline tuberculoid (BT) type of leprosy with bacterial index (BI) of less than two on the Ridley scale were treated with rifampicin (RFM) 600 mg once a month, dapsone (DDS) 100 mg daily and prothionamide (PTH) 250 mg daily. Treatment was stopped at the end of six months. The patients tolerated the drugs fairly well and in only two patients the drugs had to be stopped (in one due to jaundice and in the other due to gastric intolerance). About 6% of patients had early reactions which subsided with additional steroid therapy. The inactivity rate was 60% at six months and this improved to 96% at 12 months. No cases of late reactions and relapses were encountered in the limited follow-up period of six months; and a longer follow-up is necessary for ascertaining the relapse rates. The preliminary results however suggest that the addition of prothionamide to the standard WHO paucibacillary regimen is well-tolerated with increased inactivity rate and fewer instances of late reactions.

Adolescent↗

CD1 positive epidermal Langerhans cells in indeterminate leprosy.

Langerhans cells (LC) in the skin lesions of 10 untreated indeterminate leprosy patients were defined by indirect immunofluorescence using monoclonal antibodies. No difference was observed in the numbers and distribution of epidermal LC in the indeterminate lesions and controls. However, the infiltrates of these lesions contained CD1+ cells. Most cells in the infiltrates HLA DR antigens.

Antibodies, Monoclonal↗

Seroepidemiological studies in subsided cases of multi and paucibacillary types of leprosy using FLA-ABS test.

FLA-ABS test was carried out in 145 subsided cases of multibacillary (BL/LL) and 197 subsided cases of paucibacillary (TT/BT/I) types. The period of subsidence varied from 0-5 years or more. It was observed that percentage positivity decreases with the subsidence of the disease. In multibacillary cases, FLA-ABS positivity was 95% (active cases), 50% (after 1 year of subsidence) and 36% (after 5 years of subsidence) whereas in paucibacillary types FLA-ABS positivity was 80% (active cases), 34% (after 1 year of subsidence) and 19% (after 5 years of subsidence). A significant proportion of multibacillary subsided cases continued to be positive at high titres (1:160 and 1:640) even after 5 years of clinical subsidence. This implies the presence of continuous antigenic stimulus resulting in high antibody titres even after several years of clinical subsidence. On the other hand percentage positivity at high titres gradually decreased with the increased duration in paucibacillary cases.

Antibodies, Bacterial↗