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Biomedical subjects

K Katoch

Publications and source records attributed to K Katoch.

At least 37 records · Page 2Linked to original sources
PubMed1996

Detection of M. leprae by gene amplification; combined ethidium-bromide staining and probe hybridization.

Biopsy and skin-scraping specimens from 130 leprosy cases across the disease spectrum (56 TT/BT/I, 73 BB/BL/LL, and 1 neuritic case) and 50 healthy contacts were studied to assess the application of gene amplification. The nucleic acids from these clinical specimens were extracted by an integrated freeze-thawing--optimized lysozyme-/proteinase-k treatment-purification and fractionation procedure. The nucleic acids from cultured organisms were isolated by the stepwise procedure earlier standardized at this laboratory. Gene amplification for a 360-bp fragment of the 18-kDa protein gene was carried out using primer and the procedure described by its developers, and a 360-bp fragment on Southern blot was taken as the yardstick of positivity. The polymerase chain reaction product was analyzed by electrophoresis, ethidium-bromide (EB) staining, and blot (B) hybridization. Overall sensitivity ranged from 71% in specimens with undetectable acid-fast organisms to 100% in specimens with demonstrable acid-fast bacilli. A positivity of 73% in TT/BT/I specimens and 93% in BB/BL/LL specimens was observed. Four combinations were discerned: EB+, B+ (71%); EB-suspicious, B+ (14%); EB-, B+ (3%) and EB-, B- (12%). By combining the blot hybridization with EB staining, the sensitivity could be significantly improved as compared to EB staining alone. The test was found to be absolutely specific by the absence of any false positivity in control specimens as well as with purified DNAs from mycobacterial as well as non-mycobacterial organisms, grown from these specimens. It is recommended that for optimum sensitivity and specificity both EB staining and blot hybridization should be done.

Biopsy↗
PubMed1995

Detection of antibodies against phenolic glycolipid-1 (PGL-1), 35-kDa and 30-40-kDa components of Mycobacterium leprae in the cerebrospinal fluid of of leprosy patients.

The involvement of the central nervous system (CNS) in lepromatous leprosy (LL) patients was investigated; 33 patients were examined clinically in detail and upper motor neuron involvement was observed in eight and lower motor neuron in three of these patients. Anti-Mycobacterium leprae antibodies could be detected in the CSF by PGL-1 enzyme-linked immunosorbent assay (ELISA) and monoclonal antibody (MAb) based competitive assays against defined epitopes on the 35-kDa protein and 30-40-kDa polysaccharide (lipoarabinomannan) antigens with MAbs MLO4 and ML34, respectively. Antibodies against PGL-1 and 35-kDa protein were observed in more subjects than antibodies against the 30-40-kDa antigen. Some correlation was observed between the upper motor neuron signs and antibody positivity for 35-kDa and PGL-1 antigens in the CSF of these patients.

Adult↗
PubMed1995

Treatment of bacilliferous BL/LL cases with combined chemotherapy and immunotherapy.

Thirty-six, untreated borderline lepromatous/lepromatous (BL/LL) leprosy patients with an initial bacterial index (BI) of 4+ to 6+ were serially allocated to three treatment groups. Group I patients received a slightly modified WHO regimen (rifampin once a month, clofazimine and dapsone daily) and BCG intradermally (i.d.) (0.1 mg/per dose). Group II patients were administered the same MDT and Mycobacterium w (2 x 10(8)) killed bacilli/dose i.d., and Group III received the same MDT with 0.1 ml of distilled water i.d. Vaccination was repeated every 6 months. Biopsies were taken from the local site of vaccination and from a distant site, i.e., the back. The progress was monitored periodically by clinical, histopathological and bacterial (BI, mouse foot pad, ATP) parameters. Twenty-five patients had completed a follow up of more than 2 years. These included: 7 in Group I, 10 in Group II, and 8 in Group III. One patient of the MDT + BCG group who was progressing well dropped out after 28 months. In cases on combined chemotherapy and immunotherapy, no viable bacilli were demonstrable by mouse foot pad and ATP measurement after 6 months (at 12 months or afterward). However, in come of the control cases on MDT alone, viable bacilli could be detected even up to 18 months (by mouse foot pad) and 2 years (by ATP estimation). With 36 months of treatment, the mean BI decreased from 4.64+ to 1.66+ in the group on MDT alone (controls), 4.9+ to 0.08+ in the MDT + BCG group, and 4.75+ to 0 in the MDT+Mycobacterium w group. Compared with the MDT and MDT + BCG groups, the fall in the BI was significantly more in the MDT + Mycobacterium w group at 12, 18, and 24 months. While all of the cases in the Mycobacterium w groups became smear negative by 36 months, it took 42 months for all of the BCG group to achieve negativity. Immunotherapy appears to have a significant effect on the killing and clearance of bacilli and should be considered as an adjunct to chemotherapy, especially in bacilliferous lepromatous cases.

Adenosine Triphosphate↗
PubMed1995

Response of leprosy patients with single lesions to MDT.

This study reports the clinical profile and therapeutic response of seventy-two mono-lesions leprosy cases. These 72 cases were among 578 paucibacillary (PB) cases classified according to WHO (1982) and were followed-up on multidrug therapy (MDT). Of these 72 mono-lesion cases, 46 (64%) were tuberculoid (TT) cases, 24 (33%) were Indeterminate (Ind) cases and 2 (3%) were of borderline tuberculoid (BT) types. While 37.5% of these cases presented as macular patches, the remaining 62.5% had raised erythematous lesions. In majority of cases (94%), the lesions were present on the exposed parts like legs and feet, arms and hands, face, whereas only 6% presented on covered areas of trunk and buttocks. These cases were treated with dapsone 100 mg daily for 12 months and rifampicin 600 mg once a month for 6 months. After 6 months of MDT, lesions in 81% of the patients regressed clinically and by one year of therapy 96% of cases had regressed. Treatment was stopped in all cases by one year of therapy. There were no relapse or late reaction in the 5 years of post treatment follow-up. The response of mono-lesion PB cases was better than the multi-lesions PB cases at 6 months and during the post treatment follow-up period.

Adolescent↗
PubMed1995

Enhancement in the histological diagnosis of indeterminate leprosy by demonstration of mycobacterial antigens.

In a clinico-pathological study of Indeterminate leprosy, fifty-six cases were chosen based on specified clinical criteria. Their clinical features were noted, the smears for acid fast bacilli (AFB) were prepared from lesions, lepromin inoculation and biopsies were performed from the lesional edges. They were subsequently treated with a modified extended WHO regimen for paucibacillary leprosy. On routine hematoxylin eosin (HE) and Fite-Faraco staining of paraffin embedded sections, histopathological confirmation of Indeterminate leprosy was observed in only 17/56 (31%) of the clinically diagnosed cases whereas the remaining were labelled as non-specific pathology. Histometric analysis of all HE stained sections did not show any characteristic finding which could be considered as characteristic and discriminatory for Indeterminate leprosy. Immunoperoxidase staining for demonstration of mycobacterial antigen by direct staining procedure using conjugated rabbit anti-BCG and indirect three step procedure using primary rabbit anti-BCG and avidin biotin complex, was next performed on the sections exhibiting non-specific pathology. With the direct immunoperoxidase method, antigen was demonstrable in (11/35) 31% of the cases. The more sensitive indirect method could demonstrate the presence of antigen in (21/35) 60% of the cases. This study thus shows that demonstration of mycobacterial antigen by simple and inexpensive immunoperoxidase techniques enhances the histopathologic diagnosis of Indeterminate leprosy.

Adolescent↗
PubMed1994

Diagnostic value of gene probes and its correlation with clinical profile of leprosy in children.

Clinico-bacteriological profile of 73 leprosy patients below 16 years of age was studied. Majority of the patients were males and fell in 11-16 years age group (p < 0.05). Skin lesions were present in all cases on both exposed as well as unexposed areas and their number increased with advancing age. Cutaneous sensations were affected in most of the patients while nerve thickening was observed in 41. As age increased, the disease moved from the tuberculoid end of spectrum towards the lepromatous end (p < 0.05) and the positivity of the skin smears increased (p < 0.05). Majority of the paucibacillary cases were lepromin positive while most multibacillary cases were lepromin negative (p < 0.01). Two M. leprae specific gene probes were applied in 42 cases to assess their diagnostic value. Eighty one per cent cases were picked up by the probes indicating presence of active bacilli. These included all lepromin positive cases, all smear positive cases, and most of smear negative cases (p < 0.05). Seven children with inconclusive histology were also positive. Drug treatment and inadequate size of biopsy sample could explain the negative probe results in 19% cases. This study highlights the immense potential of gene probes in diagnosing leprosy in children.

Adolescent↗
PubMed1993

Clinical and histopathological correlation in the classification of leprosy.

This study reports our observations on the correlation between clinical and histopathological diagnoses of the classification of leprosy. The histopathological classification of leprosy in 1351 cases was done per Ridley-Jopling criteria and was compared with the clinical diagnoses of the same cases. These 1351 cases included 79 cases diagnosed clinically as having a "reaction." However, the histopathologists could not detect any evidence of reaction in 16 of these 79 cases (20%). Of the remaining 1272 cases, 68 (5%) were reported as "no evidence of leprosy" by the histopathologists; 37 of these 68 were found to be from the clinically indeterminate type of leprosy. Histopathological and clinical diagnoses of the classification of leprosy coincided in 69% of the cases. Concordance between the clinical and histopathological diagnoses for different types of leprosy was: indeterminate (I) = 36%, tuberculoid (TT) = 50%, borderline tuberculoid (BT) = 77%, borderline (BB) = 26%, borderline lepromatous (BL) = 43%, and lepromatous (LL) = 91%. When some of the types were combined (BT with TT, BL with LL), the overall concordance figure was 76%; concordance for the TT/BT group was 80%, for the BL/LL group it was 93%. Since both TT and BT are considered paucibacillary and LL or BL are considered multibacillary for treatment purposes, differentiating TT from BT or BL from LL is, perhaps, therapeutically irrelevant. However, for classification purposes it appears that the weight given to different signs and/or histopathological parameters for classifying leprosy cases (especially TT, BB and I) needs to be reassessed.

Biopsy↗
PubMed1992

Histological changes with combined chemotherapy and immunotherapy in highly bacillated lepromatous leprosy.

Highly bacillated untreated lepromatous cases with an initial BI 4+ of to 6+ were treated with combined multidrug treatment (MDT) and immunotherapy with heat killed Mycobacterium w or BCG. The vaccines were administered intradermally every six months. It was observed that majority of cases on immunotherapy showed increased lymphocytic infiltration (both at local and distant sites) and some cases showed epithelioid cells as well. The lymphocytic infiltration was (slightly) more vigorous in those vaccinated with Mycobacterium w. Such changes were not seen in the patients on MDT alone. Also, the granuloma fraction reduced much faster in cases who were on additional immunotherapy as compared to those on MDT alone. These changes along with evidence of clinical and bacteriological improvements suggest that immunotherapy may have an important supportive role specially in the therapy of anergic lepromatous cases.

Antitubercular Agents↗
PubMed1992

Suppressive effect of circulating immune complexes from leprosy patients on the lymphocyte proliferation induced by M. leprae antigens in healthy responders.

The effect of circulating immune complexes, isolated in the form of polyethylene glycol (PEG) precipitates from leprosy patients, on lymphocyte proliferation was studied. The results obtained showed that PEG precipitates obtained from the borderline lepromatous/lepromatous (BL/LL) types of leprosy patients and those undergoing erythema nodosum leprosum (ENL) had significant suppressive effects on the lymphocyte proliferation induced by Mycobacterium leprae antigens in healthy responders. The percent decreases in the mean values of delta cpm in the presence of PEG precipitates from the BL/LL and ENL groups were found to be 46.8 +/- 22.4 and 65.0 +/- 24.3, respectively. However, no significant suppressive effects (except for ENL PEG precipitates) of these PEG precipitates were observed on the lymphocyte proliferation induced by tuberculin (PPD). Further, PEG precipitates alone (in the absence of M. leprae antigen) from the BL/LL and ENL groups were found to have no effect on the lymphocyte proliferation.

Antigen-Antibody Complex↗
PubMed1992

A preliminary study of correlation of immuno-histological and ultrastructural characteristics of neural granuloma in leprosy patients.

With an aim to better understand the pathogenesis of nerve damage in leprosy, peripheral nerve biopsies from six untreated leprosy cases (3 BT/TT and 3 BL/LL) were studied by electronmicroscopy and immuno-histology. In addition to routine histopathology for diagnosis, infiltrating cells of granuloma were characterized after preparation of single cell suspension. The lymphocytes in the lesion were characterized by E and EAC rosetting and macrophage phagocytic system (MPS) cells were studied using histochemical markers like esterase and peroxidase. The results indicate that the lymphocyte content was significantly greater in tuberculoid neural granuloma compared to lepromatous nerves and these formed rosettes with sheep erythrocytes (E) and expressed HLA-DR antigen suggesting that they are activated T cells. Infiltrating macrophages in both the tuberculoid and lepromatous neural granuloma were esterase positive, peroxidase negative and did not form rosettes with sheep erythrocytes or EAC. Ultrathin sections of tuberculoid granuloma showed lymphocytes clearly associated to epithelioid macrophages having well developed Golgi apparatus and rough endoplasmic reticulum. Correlation of these immunological and ultrastructural characters suggests that hypersensitivity mechanisms are possibly responsible for nerve damage in tuberculoid leprosy. Ultrastructural examination of lepromatous nerves, on the other hand, showed the predominance of macrophages with large nucleus, heavily bacillated Schwann cells, and a few lymphocytes. The correlation of immuno-histological and ultrastructural characters indicates that the mechanism(s) of nerve damage in lepromatous leprosy are basically different wherein hypersensitivity appears to play a very limited role.

Academies and Institutes↗
PubMed1991

Association of mycobacterial-specific and Mycobacterium leprae specific antibody levels with clinical activity in tuberculoid leprosy: a comparative study of three serological enzyme-immunoassays.

The ELISAs for polyclonal antibodies against Mycobacterium leprae (ML-ELISA) and specific antibodies against epitopes on 35 kDa protein (SACT-ELISA) and phenolic glycolipid I (PG-ELISA) of M. leprae were evaluated comparatively in a group of 88 tuberculoid leprosy patients. The overall seropositivity rate with a battery of 3 tests (68%) was not significantly higher than that obtained with ML-ELISA alone (55%) for IgG class of antibodies. Seropositivities for SACT-ELISA and PG-ELISA were, respectively, 38% and 26%. ML-ELISA for IgM class of antibodies was least sensitive, showing only 8% positivity. A significant correlation was noted between individual values of the three assays, but the positive proportions overlapped maximally in the case of ML-ELISA (IgG) and SACT-ELISA. Further, positivity for the latter two assays, particularly SACT-ELISA, showed significant associations with the extent of 'active' (largely untreated) infection. Immunoblotting revealed that the main antibody response was directed towards M. leprae antigens in the molecular weight range of 20-40 kDa and the densitometry results of this zone correlated significantly with corresponding SACT-ELISA and ML-ELISA (IgG) values.

Antibodies, Bacterial↗
PubMed1991

A method for the detection of M. leprae antigens in urine of leprosy patients by gel diffusion and gel electrophoretic techniques and significance in diagnosis.

A simple and novel method has been developed for the first time to detect M. leprae antigens in the urine of leprosy patients by treating the urine samples with sodium dodecyl sulphate (SDS). The antigens thus released can be demonstrated by simpler techniques like gel diffusion. By this method about 86% antigen positivity is observed in the urine of TT/BT and 83% positivity in BB patients. In BL/LL patients the antigen positivity is observed in 87% of the subjects. The high rate of M. leprae antigen positivity by the present method in the urine of patients with early leprosy may prove to be of diagnostic significance.

Adult↗
PubMed1991

Persistent reduced solubilization of immune complexes in lepromatous leprosy patients with reactions.

It is held that immune complexes (IC) play a vital role in the pathogenesis of some of the reactions in leprosy. The complement system is known to solubilize and render IC innocuous. We have previously shown that patients undergoing lepra reactions had lowered complement-mediated IC solubilization (CMS). We, therefore, undertook a prospective study of untreated multibacillary leprosy patients and monitored their CMS levels sequentially while on therapy. In addition, the concentrations of the complement component C3d, immunoglobulins G, A and M, and circulating immune complexes (CIC) were also estimated. A total of 26 patients were included in the study and were investigated at 3-month intervals for 3 years. Thirteen of the 14 patients who did not develop reactions at all had normal CMS values, although all of them showed elevated CIC. From the inception of treatment, 10 of the 12 patients who developed lepra reactions had low CMS values which remained below normal levels even after evidence of complement activation disappeared and long after the subsidence of reaction. It is suggested that this defective CMS acts as a predisposing cause of lepra reactions.

Adult↗
PubMed1991

Antigens of Mycobacterium leprae in the cerebrospinal fluid of leprosy patients: detection by monoclonal-antibody-based sandwich immunoradiometric assay and avidin/biotin immunoblotting.

Mycobacterium leprae antigens could be detected in the cerebrospinal fluid (CSF) of patients with leprosy, using a monoclonal-antibody-based sandwich immunoradiometric assay (SIRMA). Antigens of 12 kD, 35 kD and 30-40 kD were detected using ML06, ML04, and ML34 monoclonal antibodies, respectively. The 30-40-kD polysaccharide antigen, although present in larger amounts in M. leprae than the 12-kD and 35-kD protein antigens, was found in the CSF of comparatively fewer subjects. The antigen capture assay has been found sensitive to the level of nanograms. Avidin-biotin-based immunoblotting using pooled leprosy sera detected a larger number of antigens than using anti-M. leprae antisera raised in rabbits. The immunoblotting of CSF samples revealed about three antigens in the region of 100-160 kD and three more in the region of 45-60 kD as probed by leprosy sera. This study has for the first time revealed the presence of M. leprae antigens in the CSF of leprosy patients and the probable involvement of the central nervous system in leprosy.

Antibodies, Monoclonal↗
PubMed1991

Clinical and bacteriological progress of highly bacillated BL-LL patients discontinuing treatment after different periods of MDT.

Highly bacillated lepromatous patients (BL/LL) with an initial bacterial index (BI) of 4 to 6+ are being treated with a modified World Health Organization-recommended multiple-drug therapy (WHO/MDT) regimen consisting of rifampin 600 mg once a month, clofazimine 100 mg on alternate days, and dapsone 100 mg daily. The clinical and bacteriological profiles of the patients who had discontinued treatment at different durations have been compared with patients who took the same treatment until attainment of smear negativity. All six of the patients who had discontinued treatment at 12-18 months had worsened clinically and bacteriologically, and viable bacilli could be demonstrated in those tested for ATP. In four patients who had stopped treatment at 24-30 months, the BI continued to fall and there was no clinical or bacteriological worsening in 1 to 2 years of follow-up. The fall in the BI in five cases who had discontinued treatment at 36-44 months was comparable to those on continuous treatment, and there was no worsening. These observations indicate that with the conventional MDT regimen it is not advisable to stop treatment at 12 and 18 months. It appears that treatment should be continued for at least 2 years, and longer in the untreated highly bacillated cases. Prospective clinical trials with a sufficient number of cases and long-term follow-up need to be carried out to ascertain the optimum duration.

Adolescent↗