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Biomedical subjects

M K Roy

Publications and source records attributed to M K Roy.

At least 19 recordsLinked to original sources
PubMed2005

Leiomyoma of the urinary bladder.

Benign mesenchymal tumors of the bladder are rare and comprise less than 1% of the all bladder neoplasms. Leiomyoma is the most common type and comprises 35% of these tumors. These tumors may develop in submucosal (63%), intramural (7%) or subserosal (30%) layer, at any region of the bladder. The clinical presentation is varied and may include obstructive symptoms(50%), irritative symptoms (38%) and hematuria (11%). There are asymptomatic cases (19%), which make the diagnosis more difficult. Occurs more frequently in women than in men (3:1). The most common diagnostic investigations are ultrasonography, intravenous urography, computerized tomography scan and the magnetic resonance imaging. A 66 year old man presented with long standing voiding obstructive symptoms. Various examinations were performed in the last 2 years and was diagnosed either prostatic enlargement or bladder tumor. Cystoscopy was not available for confirming the diagnosis. The surgical exploration revealed a well-circumscribed mass at the bladder neck with moderate enlargement of the prostate. The pathological examination revealed a leiomyoma of the bladder. The post operative period was uneventful and the patient is doing well, without recurrence of the symptoms.

Aged↗
PubMed2004

Effect of body temperature on mortality of acute stroke.

OBJECTIVES: The exact relation between body temperature and mortality of acute stroke victims is poorly understood. However, body temperature can affect the outcome of stroke cases in relation to mortality. In the initial (4-12 hrs) hours of stroke, the temperature rise is often neurogenic in origin and mortality is also higher with raised body temperature. Though the anatomical lesion or nature of lesion along with other established risk factors influence the mortality of stroke cases, change in temperature does affect the outcome of stroke cases. We sought to find out the significance of stroke victim's body temperature (within 4-12 hrs) with respect to short-term mortality rate in our study. METHODS: We selected 100 ischemic and 100 hemorrhagic stroke patients proved by CT scan of brain and 2-hrly oral temperature was strictly recorded for the initial 4-12 hrs of admission. RESULTS: It was evident from the study that hyperthermia (>37.5 degrees C) was associated with highest mortality rate in both hemorrhagic (51.78%) and ischemic (56.66%) cases. In normothermic group, mortality was 13.5% and 8.8% in hemorrhagic and ischemic group respectively, whereas hypothermia (<36.5 degrees C) was associated with 0 % mortality. CONCLUSION: Hyperthermia in acute stroke victim carries a bad prognostic parameter in short term basis.

Acute Disease↗
PubMed2002

Effect of outer-membrane permeabilizers on the activity of antibiotics and plant extracts against Pseudomonas aeruginosa.

Several known outer membrane permeabilizers increased susceptibility of a highly resistant pathogenic strain Pseudomonas aeruginosa to different antibiotics and plant extracts. Of all the chemicals tested, EDTA, sodium citrate and sodium hexametaphosphate (HMP) were found to be potent permeabilizers as shown by enhanced lysis of the bacteria in the presence of lysozyme. In the presence of EDTA and sodium citrate susceptibility of the strain to gentamicin and rifampicin increased markedly. The strain was resistant to vancomycin but became susceptible when grown in the presence of increasing amounts of EDTA and sodium citrate. Similar results were obtained for erythromycin when treated with sodium citrate. EDTA was found to be most potent permeabilizer in enhancing the activity of the plant extracts. Though HMP was an effective permeabilizer it had a weak or no effect on the activity of the antibiotics and plant extracts.

Anti-Bacterial Agents↗
PubMed2002

Peptides from the N-terminal end of bovine lactoferrin induce apoptosis in human leukemic (HL-60) cells.

To determine the effects of the multifunctional iron-binding glycoprotein, lactoferrin (LF) and related compounds on the growth of leukemic cells, human myeloid leukemic cells (HL-60) were exposed to bovine lactoferrin (bLF) and proteolytic hydrolysates of bLF. Pepsin hydrolysates of bLF showed a greater growth suppressive effect than tryptic hydrolysates or mature bLF. Four peptides with proliferation inhibition activity were purified from pepsin hydrolysates by ion-exchange chromatography, reverse-phase HPLC, and gel-filtration. All peptides were from the N-terminal end, in a region where lactoferricin B (Lfcin B), an antibacterial peptide, is located. Among the four peptides, peptide 1 (pep1) was found to exhibit highest activity and corresponded to residues 17 to 38 of bLF, with a molecular weight of 2753.88. The IC50 value of this peptide was 6.3 micrograms/ml. Three other peptides were less active and corresponded to sequences 1 to 16 and 45 to 48, linked by disulfide-bridge (pep2, molecular mass of 2430.13), 1 to 15 and 45 to 46 linked by disulfide bridge (pep3, molecular mass of 2017,92) and from residues 1 to 13 (pep4, molecular mass of 1558.73). Cell proliferation inhibition activity of the peptides was thought to be due to induction of apoptosis, which was evaluated by DNA ladder formation, DNA fragmentation, enhanced expression of phosphatidyl serine, and morphological changes. The IC50 values of the three peptides were confirmed using synthetic peptides and were consistent with those of purified peptides.

Amino Acid Sequence↗
PubMed2001

Isolation and structure elucidation of a new antifungal and antibacterial antibiotic produced by Streptomyces sp. 201.

An antibacterial and antifungal antibiotic was isolated from the culture filtrate of Streptomyces sp. 201, and its structure was determined as 2-methyl-heptyl isonicotinate by extensive use of NMR spectroscopy. The compound exhibited marked antimicrobial activity against Bacillus subtilis, Shigella sp., Klebsiella sp., E. coli, Proteus mirabilis, and the pathogenic fungi, Fusarium moniliforme, F. semitectum, F. oxysporum, F. solani and Rhizoctonia solani.

Anti-Bacterial Agents↗
PubMed2001

Role of ultrasonography and urinary cytology in diagnosing recurrence of superficial urinary bladder cancer compared to cystoscopy.

Urinary cytology, ultrasonogram of the urinary bladder and cystoscopy were done in 99 cases of urinary bladder cancer patients in the department of urology of Dhaka Medical College Hospital (DMCH), Dhaka, during the period from January 1997 to December 1998. Pre transurethral resection of bladder tumour (TURBT), urinary cytology was positive in 20.20% cases and ultrasound scan was positive in 96.9% cases. Histopathological examination revealed 95.96% as transitional cell carcinoma:- Grade I (3.0%), Grade II (62.6%) and Grade III (34.4%). During follow-up urinary cytology was positive in only one case whereas ultrasound scan was positive in 53.5% cases of whom only 21.6% patients had actual recurrent bladder tumours proved by cystoscopy. Statistical analysis of the three tests and histopathology showed significant variation though by Chi-square test the ultrasound scan is found superior to urinary cytology. We conclude when ultrasonography of the urinary bladder shows any suspected lesion it should be examined by cystoscope and biopsy should be taken from the suspected area for confirmation. Neither urinary cytology nor ultrasound scan can replace cystoscopic examination.

Adult↗
PubMed2000

Yeast protease B-digested skimmed milk inhibits angiotensin-I-converting-enzyme activity.

Angiotensin-1-converting-enzyme (ACE) inhibitory activity was identified in skimmed milk digested with cell-free extract of yeast Saccharomyces cerevisiae. Simultaneously, a protease enzyme involved in the production of ACE-inhibition materials in digested skimmed milk was purified to homogeneity from the cell-free extracts of S. cerevisiae by ammonium sulphate fractionation and chromatography in DEAE-Sephacel, D-tryptophan methyl ester-Sepharose 4B, Hiload Superdex G-200 and HPLC Mono-Q chromatography. The purified enzyme was identified as protease B, based on the molecular mass on SDS/PAGE and the N-terminal amino acid sequence of the enzyme. The optimum pH for digestion of skimmed milk and production of ACE-inhibition materials was pH 4.8. The IC(50) of the hydrolysate was 0.42 mg of protein/ml when skimmed milk was digested with yeast protease B.

Amino Acid Sequence↗
PubMed1999

Induction of apoptosis in HL-60 cells by skimmed milk digested with a proteolytic enzyme from the yeast Saccharomyces cerevisiae.

Bovine skimmed milk digested with cell-free extract of the yeast Saccharomyces cerevisiae was found to exhibit proliferation inhibition activity towards human leukemia (HL-60) cells. The optimum pH for digestion of skimmed milk and production of the proliferation inhibition factor was pH 4.8. Nondigested skimmed milk exhibited little suppressive effect on the proliferation of HL-60 cells. An active enzyme involved in the production of cell proliferation inhibitory materials from skimmed milk was purified from the cell-free extract of S. cerevisiae by a series of column chromatographies: DEAE-Sephacel, D-tryptophan methyl ester-Sepharose 4B, Hiload Superdex G-200 and HPLC Mono Q. The homogeneous purified enzyme and exhibited a molecular mass of 33 kDa in sodium dodeceyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and was identified as protease B by N-terminal amino acid sequence analysis. Bovine skimmed milk digested with purified protease B was found to inhibit proliferation activity of HL-60 cells most strongly when digestion was conducted at pH 4.8. The cell proliferation inhibition activity induced by digested skimmed milk was shown to be due to the induction of apoptosis, demonstrated by the formation of apoptotic bodies and fragmentation of DNA in treated cells. The proliferation inhibition factors produced were recovered in the soluble fraction of 92% ethanol, suggesting that the factors were hydrophilic low molecular mass substances derived from skimmed milk.

Journal Article↗
PubMed1999

Distribution of phage type of Vibrio cholerae O1 biotype ElTor in Indian scenario (1991-98).

During the period 1991-98, distribution of biotype, serotype and phage type of V. cholerae O1 strains isolated from different parts of the country and referred to the National Institute of Cholera and Enteric Diseases, Calcutta were studied. Of the 8101 strains received, 5613 (69.2%) were subjected to phage typing. All these strains belonged to the biotype ElTor and Ogawa was the predominant serotype (96.08%). The strains were clustered into only two types--types 2 and 4 and around 10 per cent strains remained untypable. However, using the new scheme, all these strains were found to be typable and 8 major types were recognized of which type number 27 was the predominant type (66.12%). The distribution of a common type throughout the country suggests that a particular clone of V. cholerae O1 is probably circulating all over India. A constant monitoring through phage typing is necessary to observe the emergence of any new clone of V. cholerae O1 in India.

Bacterial Typing Techniques↗
PubMed1999

Coordinate production of cephamycin c and clavulanic acid by Streptomyces clavuligerus.

Production of cephamycin c and clavulanic acid by Streptomyces clavuligerus was investigated using different media in shake flask condition. Highest cell growth (3.8 g/L) was observed in glycerol, sucrose, proline and glutamic acid (GSPG) medium. Although, GSPG medium supported maximum growth, it was least effective for the synthesis of both cephamycin and clavulanic acid. Yield of cephamycin and clavulanic acid was maximum in dextrin and K medium, respectively. High and low level of constituents of dextrin medium, affected production of both cephamycin and clavulanic acid. Biosynthesis of clavulanic acid was associated with production of cephamycin c.

Anti-Bacterial Agents↗
PubMed1998

Degradation of fenitrothion by Bacillus stearothermophilus adhering to silica.

B. stearothermophilus strain AG-49, when cultivated in mineral medium in the presence of silica (SA), adhered to SA. Adhesion depended on age of culture, contact time and glucose concentration of the culture medium. Mid-exponential phase culture (5 h) required minimum contact time (30 min) for maximum adhesion. 0.6% glucose concentration was optimum. Quantitative variation in protein and saccharide extractable in sodium chloride and sodium dodecyl sulfate (SDS) was observed. Five % degradation of fenitrothion by adherent B. stearothermophilus could be achieved in 4 d.

Bacterial Adhesion↗
PubMed1998

Experimental biofilm and its application in malathion degradation.

Mixed bacterial culture consisting of three different strains of Micrococcus sp. (AG 36, AG 94 and AG 98) and two strains of Pseudomonas sp. (AG 7 and AG 52) and its individual components was passed through a sand column and 25.5-92% of cell dry mass was found to be retained (adsorbed) on it. Incubation of sand soaked in mineral medium containing glucose as a sole carbon source resulted in formation of a biofilm with 1.2-2.5-fold increase in biomass. A 61% degradation of malathion by the mixed culture biofilm could be achieved in 4 d.

Bacterial Adhesion↗
PubMed1998

In vitro transformation of ampicillin to cephalexin by free and immobilized cells of Streptomyces sp.

In vitro transformation of ampicillin to cephalexin was studied using calcium alginate-immobilized and free Streptomyces sp. strain DRS-1 packed in glass columns. Tris-HCl buffer containing ampicillin was continuously circulated through the columns for four cycles, each cycle (with fresh ampicillin) being continued for 5 h. The pattern of product formation was identical in both cases, i.e. in each cycle, after reaching a certain concentration, its formation did not increase. Product formation was always higher with immobilized cells. Conversion of ampicillin to cephalexin by the strain was affected by cell and substrate concentration.

Alginates↗