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Biomedical subjects

K Misra

Publications and source records attributed to K Misra.

At least 37 records · Page 2Linked to original sources
PubMed1995

Glyoxalase III from Escherichia coli: a single novel enzyme for the conversion of methylglyoxal into D-lactate without reduced glutathione.

A single novel enzyme, glyoxalase III, which catalyses the conversion of methylglyoxal into D-lactate without involvement of GSH, has been detected in and purified from Escherichia coli. Of several carbonyl compounds tested, only the alpha-ketoaldehydes methylglyoxal and phenylglyoxal were found to be substrates for this enzyme. Glyoxalase III is active over a wide range of pH with no sharp pH optimum. In its native form it has an M(r) of 82000 +/- 2000, and it is composed of two subunits of equal M(r). Glutathione analogues, which are inhibitors of glyoxalase I, do not inhibit glyoxalase III. Glyoxalase III is found to be sensitive to thiol-blocking reagents. The p-hydroxymercuribenzoate-inactivated enzyme could be almost completely re-activated by dithiothreitol and other thiol-group-containing compounds, indicating the possible involvement of thiol group(s) at or near the active site of the enzyme.

Aldehyde Oxidoreductases↗
PubMed1995

Comparison of pleural fluid cytology and pleural biopsy in the evaluation of pleural effusion.

Pleural fluid cytology and pleural biopsy results were studied in 65 cases of pleural effusion. The efficacy of pleural biopsy in diagnosis of neoplastic and non-neoplastic pleural diseases was compared. Of the 24 cases with confirmatory evidence of cancer, 17(70.8%) has positive cytologic findings in pleural fluid, whereas pleural biopsy was diagnostic in only 13 cases (54.1%). For non-malignant pleural effusion in 41 cases 40(97.5%) has a definite diagnosis (tuberculous pleuritis, acute fibrinous pleuritis or hydatid cyst) which could be made by cytology while only 31(75.6%) out of 41 were diagnosed on pleural biopsy. The study indicates that cytologic evaluation of pleural fluid is more efficaceous in the diagnosis of malignant and non-malignant pleural disease than percutaneous pleural biopsy.

Biopsy, Needle↗
PubMed1995

A novel strategy for O6-protection of guanosine.

A "one-pot reaction" has been used for simultaneous protection of amino and O6-function of deoxyguanosine. N-(4-bromobutyl) phthalimide used for O6-protection generates an alkylamino function after mild base hydrolysis. Two sequences d(GGA) and d(GGATCC) have been synthesised with all protected guanosine units. Similarly, 2-(vinyl)pyridine has also been used for O6-protection following the same strategy.

Base Sequence↗
PubMed1995

Fluorophores for labeling of DNA/RNA fragments.

Three fluorescent tags, viz. 4-acetylamino-(N-caproyl)-1,8-naphthalimide, 4-acetylamino-(N-p-carboxyphenyl)-1,8-naphthalimide and 4-acetylamino-1,8-naphthalic anhydride have been synthesized starting from acenaphthene. These were characterized by chromatographic and spectroscopic studies and their relative fluorescence assessed under different conditions. An octamer d(TCTTGCTC) complementary to tat initiator of HIV-1, SK 102(+), a 33-mer and SK 19(+), a 41-mer complementary to a highly conserved region of HIV-1 genome were synthesized. 4-Acetylamino-(N-caproyl)-1, 8-naphthalimide was tagged via its carboxyl function to the 5'-end of these oligonucleotides by generating aliphatic amino function through the reaction of 5'-hydroxyl with carbonyldiimidazole and subsequently with hexamethylenediamine. The resultant labelled oligonucleotides were purified by HPLC on RPC C18 column and showed significant fluorescence.

Base Sequence↗
PubMed1992

Nucleolar organizer regions in FNAC smears of breast lesions.

The argyrophil technique for staining proteins associated with nucleolar organizing regions was applied to the fine-needle aspiration cytology smears of 45 cases of breast disease. These included 14 malignant and 31 benign lesions. A correlation with histology sections was done in 12 cases. There was a significant difference between AgNOR count of benign and malignant breast disease with one case out of 45 falling in the "gray" zone of overlap. Infiltrating lobular carcinoma was found to have the lowest NOR counts among the malignant lesions. The smear staining was superior to that on sections, the positive features being lack of background staining and better dispersion of NORs in the nucleoli.

Biopsy, Needle↗
PubMed1990

Aspiration cytology of hemangiopericytoma: a report on two cases.

The cytological features of fine-needle aspiration in two cases of hemangiopericytoma are described. The diagnosis was confirmed by cell block and the silver impregnation method, demonstrating reticulin fibers on smears as well as on the cell block. Histopathological correlation was done in both cases.

Adult↗
PubMed1990

Use of homologous platelet factors in achieving total healing of recalcitrant skin ulcers.

We used homologous platelet-derived wound healing factors (HPDWHF) to achieve complete healing of recalcitrant ulcers of diverse cause. Twenty-three patients with 27 skin ulcers who had been receiving conventional wound care with no evidence of healing for an average period of 25 weeks (range, 12 to 156 weeks) were studied. The patients were first subjected to controlled wound care for 3 months, with saline solution and silver sulfadiazine dressings used in all cases. At the end of this period, persistent nonhealing ulcers were treated by topical use of HPDWHF and silver sulfadiazine. Ulcer parameters were recorded on the first day and every week during therapy until complete epithelization was achieved in either group. Each ulcer acted as its own control. In the controlled wound care group, only three ulcers in three patients achieved complete healing; the remaining 24 ulcers in 20 patients failed to achieve even 50% healing in the stipulated 3-month period. However, when subjected to HPDWHF applications, these ulcers healed completely, 100% healing occurring in 9.67 +/- 4.9 weeks (range, 3 to 19 weeks), which is highly significant (p less than 0.01). The healing response to HPDWHF applications was of uniform progression over the weeks. Only the basic cause of the ulcer determined the healing rates in this group. The shortest and the longest time to achieve 100% healing occurred in patients with diabetes (6.88 +/- 2.97 weeks) and in the venous stasis group (14.00 +/- 7.07 weeks). Age, sex, location of ulcer, ulcer duration, and ulcer measurements had no influence on the HPDWHF-stimulated healing rates. This is the earliest report of HPDWHF-stimulated repair in chronic nonhealing skin ulcers.

Adolescent↗
PubMed1989

Highly efficient synthesis of oligodeoxyribonucleotides using alpha-phenyl cinnamoyl group for selective amino protection.

alpha-phenyl cinnamoyl (alpha-PhCm) group has been found to be highly selective for exocylic amino function of all the three deoxynucleosides viz, 2'-deoxyadenosine, 2'-deoxyguanosine and 2'-deoxycytidine. The stereospecific nature of the group confers stability to the N-protected derivatives of 2'-deoxyadenosine and 2'-deoxyguanosine towards acids thereby minimising depurination. The easy preparation and introduction of the group, stability of the protected monomers, milder conditions for deprotection resulting in negligible side products during synthesis and above all hydrophobicity of the group are the additional advantages.

Base Sequence↗
PubMed1989

Histopathological study of xanthogranulomatous cholecystitis.

A total of 418 gallbladders removed surgically as chronic cholecystitis or carcinoma gallbladder were studied retrospectively for the presence of xanthogranulomas which were found in 45 (10.8%). The age of patients with xanthogranulomatous cholecystitis ranged from 15 to 80 yr with a mean of 45.3 indicating an early presentation of the disease in our population. The male to female ratio was 1:8. The gallbladder was invariably thickened and calculi of cholesterol or mixed type were present in all cases. Xanthogranulomatous foci appeared as yellowish nodules 2-15 mm in size, on the mucosal surface. In some gallbladders, the involvement was diffuse and these foci extended to the surrounding structures. Histologically, xanthogranulomas encompassed the full thickness of the gallbladder wall with variable extension into adjacent fat and connective tissue. This entity deserves distinct clinicopathological recognition, particularly because of a possible confusion with malignancy and the associated complications.

Adolescent↗
PubMed1986

Improved synthesis of oligodeoxyribonucleotide using 3-methoxy-4-phenoxybenzoyl group for amino protection.

3-Methoxy-4-phenoxybenzoyl group has been used for the protection of exocyclic amino group of nucleosides. In case of 2'-deoxycytidine it has been found to be highly selective under controlled conditions. The N-protected derivatives of 2'-deoxyadenosine and 2'-deoxyguanosine have been found to be sufficiently stable towards acids minimising depurination under conditions of synthesis of oligodeoxyribonucleotide on solid support via phosphotriester approach. The high lipophilicity of the group and milder deprotection conditions are additional advantages.

Methods↗