Biomedical subjects

K K Das

Publications and source records attributed to K K Das.

At least 19 recordsLinked to original sources

PubMed2003

Gastric intestinal metaplasia as detected by a monoclonal antibody is highly associated with gastric adenocarcinoma.

BACKGROUND: Some forms of gastric intestinal metaplasia (GIM) may be precancerous but the cellular phenotype that predisposes to gastric carcinogenesis is not well characterised. Mucin staining, as a means of differentiating GIM, is difficult. A monoclonal antibody, mAb Das-1 (initially called 7E(12)H(12)), whose staining is phenotypically specific to colon epithelium, was used to investigate this issue. METHODS: Using mAb Das-1, by a sensitive immunoperoxidase assay, we examined histologically confirmed GIM specimens from two countries, the USA and Japan. A total of 150 patients comprised three groups: group A, GIM (fields away from the cancer area) from patients with gastric carcinoma (n=60); group B, GIM with chronic gastritis (without gastric carcinoma) (n=72); and group C, chronic gastritis without GIM (n=18). RESULTS: Fifty six of 60 (93%) patients with GIM (both goblet and non-goblet metaplastic cells) from group A reacted intensely with mAb Das-1. Cancer areas from the same 56 patients also reacted. In contrast, 25/72 (35%) samples of GIM from patients in group B reacted with mAb Das-1 (group A v B, p<0.0001). None of the samples from group C reacted with the mAb. CONCLUSIONS: Reactivity of mAb Das-1 is clinically useful to simplify and differentiate the phenotypes of GIM. The colonic phenotype of GIM, as identified by mAb Das-1, is strongly associated with gastric carcinoma.

Adenocarcinoma↗

PubMed2001

The influence of ascorbic acid on nickel-induced hepatic lipid peroxidation in rats.

We studied the effect of oral ascorbic acid treatment on nickel sulfate-induced lipid peroxidation in the liver of Wistar strain male albino rats. Lipid peroxide and glutathione levels and the activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were estimated in liver. Nickel sulfate administration significantly increased the level of lipid peroxides and decreased glutathione, SOD, CAT, and GSH-Px activities in liver. The simultaneous administration of ascorbic acid with nickel sulfate resulted in a remarkable improvement of lipid peroxide, glutathione, SOD, CAT, and GSH-Px status in liver in comparison with rats treated with nickel alone. Nickel sulfate has an adverse effect on hepatic lipid peroxidation in animals, but simultaneous treatment with ascorbic acid offers a relative protection against nickel-induced hepatotoxicity.

Administration, Oral↗

PubMed2001

Large capillary haemangioma arising from the nasal columella--a case report.

A 39-year-old male presented with a mass arising from the nasal columella for last 8 months. The mass was lobulated, dark red in colour, firm in consistency and approximately 3 cm in diameter. It was attached to the columella of the nose by a narrow stalk. The mass was excised completely under general anaesthesia and histopathological examination suggested it to be a case of capillary haemangioma.

Adult↗

PubMed2001

Physical fitness: a longitudinal study among Muslim children of Bijapur (Karnataka).

Aerobic capacity or maximum oxygen uptake capacity (VO2 max) has been widely considered to be reliable and valid measure of cardio respiratory fitness. Persons possessing higher values and have the capacity to yield larger amounts of energy, are capable of performing better in athletic and other field activities. Seventy school going children from the Muslim community of Bijapur (Karnataka) aged 12-16 years (means +/- SEM = 14.33 +/- 0.94), volunteered for this study. Their height (cm) and weight (kg) were measured as physical anthropometry and Body mass index (BMI) was calculated (kg/m2). VO2max (ml.kg-1.min-1) was determined by applying the step test study of Margaria et al. The Physical fitness index (PFI) of the subjects were assessed by Harvard Step Test. The physiological endurance measured as VO2max (ml.kg-1.min-1) was found to be 34.31 +/- 2.44 S.E.M, which is lower in comparison to their Caucasian counterparts but nearly similar when compared with their Indian counterparts. The present study reveals that VO2max significantly correlates with BMI and PFI score. The present study also reveals that 27.2%, 20.07%, 15.77%, 14.37% and 22.87% of the subjects are in excellent, very good, good, average and poor classifications of fitness level respectively.

Adolescent↗

PubMed2000

Effect of nickel on testicular nucleic acid concentrations of rats on protein restriction.

The nucleic acids (DNA and RNA) and total protein concentration in testes were estimated in male Wistar strain rats treated intraperitorally with nickel sulfate (2.0 mg/100 g body weight) on alternate days for 10 dosages. In both normal (18% casein) and protein-restricted (5% casein) experimental animals, the nucleic acids and total protein concentration were found to decrease significantly compared to the corresponding controls. Sperm count and sperm motility were also reduced in both experimental groups of animals. The results indicate that nickel influences the expression of genetic information by reducing testicular nucleic acids and protein concentration in both dietary experimental groups.

Animals↗

PubMed1997

Alteration of testicular biochemistry during protein restriction in nickel treated rats.

Nickel sulfate (2.0 mg/100 g.b.wt) dissolved in double-distilled water was administered (i.p.) on alternate days for ten doses to normal protein-fed and protein-restricted Wister strain albino rats (b.wt. 160 +/- 5 g). Two groups were used: one with normal protein diet, whereas the other with protein-restricted diet served as control. Twenty-four hours after the last treatment, the animals were sacrificed by decapitation. Tissues such as the testes, seminal vesicles, epididymis (Cauda and Caput) and prostate were dissected out, wiped clean, and stored at -20 degrees C until analysis. Lactate dehydrogenase (LDH) activities, glutamate oxaloacetate transaminase (GOT) activities, glycogen content, cholesterol content, and total protein content of the testes were estimated. Nickel sulfate administration significantly decreased the body weight of both normal protein-fed and protein-restricted groups of animals; the organ weights were also decreased. Significant decrease of LDH activity was observed, but GOT activity was not altered significantly. Testicular glycogen and cholesterol increased significantly in both experimental groups, but total protein content decreased. Nickel sulfate seems to have an adverse effect on the male reproductive system in both groups of animals fed with normal protein (18% casein) diet and protein restricted (5% casein) diet.

Animals↗

PubMed1997

Influence of ascorbic acid on acid and alkaline phosphatase activities in some metabolically active tissues of aspirin treated rats.

ACP and ALP activities in plasma were increased in aspirin treated groups for a period of seven days. Ascorbic acid supplemented groups showed no significant change in plasma ACP activity, but a significant change in ALP activity was found. ACP and ALP activities in liver and kidney were decreased significantly in aspirin treated animals. ACP activities in liver and kidney in ascorbic acid supplemented groups showed no significant changes. No significant alteration of ALP activity in liver was found in ascorbic acid supplemented group but a significant changes was observed in kidney. Supplementation of ascorbic acid in high doses to rats fed aspirin can restore enzyme activities almost to the normal level.

Acid Phosphatase↗

PubMed1997

Efficacy of methotrexate in rheumatoid arthritis.

Rheumatoid arthritis is a common inflammatory articular disorder in Bangladesh. Methotrexate has proved to be an effective and relatively safe disease modifying drug for this disease. A quasiexperimental trial of the efficacy of methotrexate in rheumatoid arthritis was carried out in the Rheumatology Clinic, Institute of Postgraduate Medicine & Research, Dhaka during the period between July 1992 and September 1993. Thirty eight patients fulfilling the revised ARA criteria were given methotrexate in a total weekly dose of 7.5 to 15 mg. They were followed up at weekly intervals for one month and then monthly for a total duration of six months. Twenty three subjects eventually completed the trial. The trial showed significant differences in the disease activity indices at the end of six months. The decline of activity was noted at the end of one month. As a whole the response was complete in 4(17%), marked in 14(61%), moderate in 4(17%) and nil in 1(4%). Adverse effects occurred in 27 subjects. They were mild and transient in 22. Methotrexate appeared to be an acceptable DMARD for our rheumatoid arthritis population.

Adult↗

PubMed1995

Efficacy of ciprofloxacin in enteric fever: comparison of treatment duration in sensitive and multidrug-resistant Salmonella.

The efficacy of two regimens of ciprofloxacin was compared in a randomized study conducted on 69 patients with enteric fever, 52.2% of whom had infection with multidrug-resistant (MDR) strains of Salmonella typhi or S. paratyphi. Patients were randomly assigned to two regimens (10 days versus 14 days) of ciprofloxacin (500 mg twice a day). The mean +/- SD time required for defervescence was similar for both regimens (4.2 +/- 1.9 days in the 10-day group and 4.9 +/- 2.6 days in the 14-day group). A 100% cure was observed in each treatment group and no serious side effects were observed. Relapse occurred in two patients (14-day regimen). Only one patient (14-day regimen) had growth of S. typhi in stool culture at the time of the first follow-up three days after completion of therapy. Follow-up studies on available patients on two, six, and 12 months after completion of therapy revealed that all patients had negative stool cultures for S. typhi and S. paratyphi. This study indicates that ciprofloxacin may be recommended as an initial therapy for enteric fever for adult men and nonpregnant and nonlactating women in areas where MDR strains of S. typhi and S. paratyphi are prevalent, and that 500 mg twice a day of the drug given for 10 days is as effective as 14 days at the same dosage.

Adolescent↗

PubMed1995

Place of transvaginal sonography in the evaluation of reproductive endocrinology.

A high frequency vaginal probe with improved resolution offers a remarkable sharp clear image of pelvic organs. This is possible because of its closed proximity with target organ and non-intervention by gut or omentum. Study of ovarian follicular dynamics (folliculometry), identification of proliferative, secretory and decidual changes of endometrium (endometrial dating) in different phases of menstrual cycle and imaging of mucus secretion in the cervical canal (cervical mucus study) in the pre-ovulatory phase is possible by transvaginal probe. It is non-invasive, acceptable to patients, and thus can be repeated any number of times. A close serial monitoring offers immense wealth of information about the anatomical as well as reproductive endocrinal status of the patient. Ovulation can be predicted in advance. The case of dysovulation can be identified in first cycle of study; corrective therapy can be started in another two or three cycles, aiming at achieving perfect folliculogenesis. Once well tuned synchronised cycle is restored, the pregnancy outcome is remarkable. Thus transvaginal sonography offers one of the best reproductive endocrinology evaluation in the hand of a modern gynaecological sonologist and infertility specialist.

Female↗

PubMed1995

Role of transvaginal sonography in pelvic scan for female reproductive system.

Three hundred twenty-nine cases of early pregnancy and 116 pelvic pathology studied by transabdominal sonography were compared with 81 cases of early pregnancy and 88 cases of pelvic pathology subjected to transvaginal sonography. A high frequency vaginal probe, because of its close proximity with the target organ, produces remarkably sharp image. An accurate diagnosis is possible in great majority of cases within a short time. Vaginal sonography is done with an empty bladder. A close serial monitoring of ovarian follicles, endometrium and cervical mucus with transvaginal sonography offers an immense wealth of information about the structural and reproductive endocrinal status of the patient. Ovulation can be predicted in advance. Imaging of female reproductive system by transvaginal sonography is indispensable for any modern gynaecological care and for infertility assessment in particular.

Female↗

PubMed1992

In vitro biosynthesis of GbOse4Cer (globoside) and GM2 ganglioside by the (1-->3) and (1-->4)-N-acetyl beta-D-galactosaminyltransferases from embryonic chicken brain. Solubilization, purification, and characterization of the transferases.

(1-->4)-N-Acetyl-beta-D-galactosaminyltransferase (GalNAcT-1) and (1-->3)-N-acetyl-beta-D-galactosaminyltransferase (GalNAcT-2), which are involved in the in vitro biosynthesis of GM2 and GbOse4Cer glycosphingolipids, respectively, have been solubilized and separated by differential detergent extraction from a membrane preparation of 19-day-old embryonic chicken brain. The separated GalNAcT-1 activity had a pH optima of 7.8-8.0, and the separated GalNAcT-2 activity a single pH optimum of 7.2. Furthermore, the partially purified GalNAcT-2 preparation catalyzed the transfer of N-acetylgalactosamine from UDP-D-[3H]GalNAc to only GbOse3Cer and nLcOse5Cer. Both GalNAcT-1 and GalNAcT-2 activities were purified to approximately 316- and 428-fold, respectively, by use of UDP-hexanolamine-Sepharose 4B affinity-column chromatography. However, the partially purified GalNAcT-1 preparation appeared to be active only with GM3, lactosylceramide, and lactotriaosylceramide. The proposed linkage of the N-acetylgalactosamine unit incorporated into GM3 is beta-D-GalpNAc-(1-->4)-GM3 from the isolation of [3H]threitol after hydrolysis of the desialylated, lead tetraacetate-treated, enzymic product, beta-D-GalpNAc-(1-->4)-beta-D-[6-3H]Galp-(1-->4)-beta-D-Glcp-(1-->1)-Cer . In addition, beta-D-GalpNAc-(1-->3)-GbOse3Cer was produced, as shown by the identification of 2,4,6-tri-O-methyl-galactose after permethylation and hydrolysis of the GalNAcT-2 enzymic product, GalpNAc-[6-3H]Galp--->Gal-->Glc-->Cer.

Animals↗

PubMed1991

Biosynthesis in vitro of GlcA beta 1-3nLcOse4Cer by a novel glucuronyltransferase (GlcAT-1) from embryonic chicken brain.

A novel glucuronyltransferase (GlcAT-1) has been detected in embryonic chicken brains. This enzyme catalyzes the biosynthesis in vitro of glucuronic acid containing glycolipids starting from neolactotetraosylceramide (nLcOse4Cer) and neolactohexaosylceramide (nLcOse6Cer). The activity is present primarily in the Golgi-rich membrane fraction and can be extracted (60%) from the membrane using a neutral detergent, Nonidet P-40, at pH 7.0. The detergent-solubilized GlcAT-1 is stable (70%) at -20 degrees C for at least 4 months. Both membrane-bound GlcAT-1 and solubilized GlcAT-1 show similar pH optima, 6.5-7.0, in HEPES buffer. The Km values were 15 and 200 microM with UDP-[14C] GlcA and nLcOse4Cer, respectively, when the detergent-solubilized supernatant fraction was used as enzyme source. The purified 14C radioactive product that comigrated with chemically characterized GlcA beta 1-3nLcOse4Cer (GlcA-nLc4) also yielded a positive immunostain with monoclonal antibody (human IgM-RI). The anomeric linkage was established as beta-linked GlcA to the terminal galactose of the substrate, as evidenced by 90-99% cleavage of the terminal [14C] GlcA by purified Helix pomatia and limpet glucuronidases. Permethylation studies of the radioactive product obtained from [6-3H]Gal beta 1-4LcOse3Cer and non-radioactive UDP-GlcA showed the presence of 2,4,6-tri-O-methylgalactose in the hydrolyzed enzymatic product. These studies established the structure of the biosynthesized product from nLcOse4Cer as GlcA beta 1-3Gal beta 1-4 GlcNAc beta 1-3Gal beta 1-4Glc-ceramide.

Animals↗

PubMed1991

Biosynthesis in vitro of core lacto-series glycosphingolipids by N-acetyl-D-glucosaminyltransferases from human colon carcinoma cells, Colo 205.

Two N-acetyl-D-glucosaminyltransferases have been detected in human colon carcinoma Colo 205 cells. These enzymes catalyze the biosynthesis in vitro of the core-glycolipid of Type 1 and Type 2 lacto-series antigens and of the polylactosamine-containing longer chain antigenic structures, respectively. The first enzyme, GlcNAcT-1, which catalyzes the formation of lactotriosylceramide [LcOse3Cer, beta-D-GlcpNAc-(1----3)-LcOse2Cer, the core for all lacto-series Type 1 and Type 2 chains] from lactosylceramide [beta-D-Galp-(1----4)-D-Glcp-Cer, LcOse2Cer] and UDP-GlcNAc shows optimum activity in the presence of nonionic detergent Triton CF-54. The other enzyme, GlcNAcT-2, which catalyzes the biosynthesis in vitro of iLcOse5Cer [beta-D-GlcpNAc-(1----3)-nLcOse4Cer, the core for polylactosamine-containing antigens] from nLcOse4Cer [beta-D-Galp-(1----4)-LcOse3Cer] and UDP-GlcNAc, is optimally active with the zwitterionic detergent, Zwittergent 3-14, when membrane-bound. Both of these activities, however, can be extracted from the membrane by use of a nonionic detergent. Triton X-114, with nearly the same efficiency. These two transferases showed different pH optima, different cation and anion effects, and differential heat-inactivation patterns at 55 degrees. Permethylation studies of the radioactive products isolated from both of the enzyme-catalyzed reactions using respective 3H-substrates and nonradioactive UDP-GlcNAc showed the presence of 2,4,6-tri-O-methylgalactose in the hydrolyzed products. This indicated the presence of a (1----3)-linked beta-D-GlcpNAc group at the nonreducing end in both cases. The linkage of the beta-D-GlcpNAc group to the subterminal D-Gal residue in the two products was confirmed by an almost 90% cleavage of the terminal [3H]GlcNAc group by purified clam and papaya beta-D-hexosaminidases.

Antigens↗

PubMed1990

Effect of a fatty acid moiety of phospholipid and ceramide on purified GalT-3 (UDP-Gal:GM2 beta 1-3 galactosyltransferase) activity from embryonic chicken brain.

Galactosyltransferase, GalT-3 (UDP-Gal:GM2 beta 1-3 galactosyltransferase) has been characterized and solubilized from 19-day-old embryonic chicken brain, and purified to over 2000-fold using mixed-modal chromatography on a omega-aminohexyl Sepharose column and affinity chromatography on a UDP-hexanolamine Sepharose column. The activity of purified GalT-3 was modulated by phospholipids in vitro with stimulation observed specifically with dipalmitoyl phosphatidylethanolamine (PE). All natural phospholipids tested (PE, PC and PI) inhibited GalT-3 activity. Enzyme activity was affected by the structure of the phospholipid vesicle. It was stabilized by the hexagonal (dipalmitoyl PE) structure and inhibited by the bilayer (dielaidoyl PE) structure. The long-chain fatty acid moiety of the glycosphingolipid substrate, GM2, was found to be necessary for optimum enzyme activity. In the absence of fatty acid, the modified substrates, lyso-GM2 and acetyl-GM2, had a 10-fold increased Km and a 4-8 fold decreased Vmax compared to the normal substrate. We postulate that GalT-3 belongs to a group of glycosyltransferases having recognition for both the carbohydrate as well as the hydrophobic domains (HY-CARS) of their substrates and that the fatty acid moiety of either the substrate (GM2) or a heterotropic effector (phospholipid) plays an important role in regulating the activity of this enzyme.

Animals↗

PubMed1990

Carbohydrate and hydrophobic-carbohydrate recognition sites (CARS and HY-CARS) in solubilized glycosyltransferases.

Six different glycosyltransferases that are active with glycosphingolipid substrates have been purified from Golgi-membranes after solubilization with detergents. It appears that GalT-4(UDP-Gal:GlcNAc-R1 beta 1-4GalT), GalNAcT-2(UDP-Gal:Gal alpha-R2 beta 1-3GalNAcT) and FucT-2(GDP-Fuc:Gal beta GlcNAc-R3 alpha 1-2FucT) are specific for oligosaccharides bound to ceramide or to a protein moiety. These are called CARS (carbohydrate recognition sites) glycosyltransferases (GLTs). On the other hand, GalT-3(UDP-Gal:GM2 beta 1-3GalT), GalNAcT-1(UDP-GalNAc:GM3 beta 1-4GalNAcT) and FucT-3 (GDP-Fuc:LM1 alpha 1-3FucT) recognize both hydrophobic moieties (fatty acid of ceramide) as well as the oligosaccharide chains of the substrates. These GLTs are called HY-CARS (hydrophobic and carbohydrate recognition sites). D-Erythro-sphingosine (100-500 microM) modulates the in vitro activities of these GLTs. Modulation depends on the binding of D-sphingosine to a protein backbone, perhaps on more than one site and beyond transmembrane hydrophobic domains. Control of GLTs by free D-sphingosine was suggested with the concomitant discovery of ceramide glycanase in rabbit mammary tissues. The role of free sphingosine as an in vivo homotropic modulator of glycosyltransferases is becoming apparent.

Animals↗

PubMed1990

Characterization of solubilized GlcAT-1 (UDP-GlcA: nLcOse4Cer beta 1-3 glucuronyltransferase) activity from embryonic chicken brain and its inhibition by D-erythro-sphingosine.

Glycolipid glucuronyltransferase activity (GlcAT-1) has been solubilized and characterized from 19-day-old embryonic chicken brain Golgi-rich membranes. The enzyme catalyzes the biosynthesis in vitro of GlcA beta 1-3nLcOse4Cer glycolipid using neolactetraosylceramide (nLcOse4Cer, Gal beta 1-4GlcNAc beta 1-3Gal beta-1-4Glc-Cer) as the substrate. The membrane-bound enzyme shows optimum activity in the presence of neutral detergents such as Triton CF-54, Triton DF-12, and Nonidet P-40. Approximately 60% of the enzyme activity can be solubilized from the Golgi membrane by Nonidet P-40. The solubilized GlcAT-1 activity is inhibited by different salts such as NaCl, NaBr, NaI, and NaOAc, but not by sodium fluoride (up to 0.4 M concentration). Desialyzed alpha 1 acid glycoprotein (SA alpha 1AGP) can be used as a substrate for glucuronyltransferase. Competition studies between glycolipid (nLcOse4Cer) and glycoprotein SA alpha 1AGP) substrates show a mixed type of inhibition. Phospholipids, in particular phosphatidylglycerol, stimulate solubilized GlcAT-1 activity, while D-erythro-sphingosine, a metabolite of glycosphingolipids, is inhibitory (50% inhibition at 0.8 mM D-erythro-sph). These results demonstrate that both phospholipid as well as sphingosine might be involved in modulating glucuronyltransferase activity.

Animals↗

PubMed1988

Solubilized glycosyltransferases and biosynthesis in vitro of glycolipids.

The assembly of most of the ceramide-linked glycolipids (GSLs) in eukaryotic cells occurs in Golgi bodies. At least 18 different glycolipid:glycosyltransferases (GSL:GLTs) have been characterized, 10 of which have been solubilized. These GLTs can be classified into 2 distinct groups: 1) GLTs dedicated to either Dol-P-P-sugar(s) or ceramide-linked sugar(s); and 2) GLTs with dual loyalties (i.e., they compete with glycolipid- and glycoprotein-bound oligosaccharides). Studies with solubilized and purified GalNAcT-1 and GalNAcT-2 from embryonic chicken brains prove that GalNAcT-1 (UDP-GalNAc:GM3 beta 1-4GalNAcT) is specific for GSL, whereas GalNAcT-2 (UDP-GalNAc:Gb3 beta 1-3GalNAcT) can transfer to an oligosaccharide containing the alpha-linked terminal galactose. Similarly, GalT-3 (UDP-Gal:GM2 beta 1-3GalT) is more specific for ganglio-oligosaccharide and GalT-4 (UDP-Gal:Lc3 beta 1-4GalT) can transfer galactose to N-acetylglucosamine linked to p-nitrophenol, glycolipid or glycoprotein. Both GalT-3 and GalT-4 have been separated and purified from embryonic chicken brains. Studies with solubilized SAT-4 and SAT-3, from bovine spleen and embryonic chicken brains, respectively, suggest the existence of 2 different gene-expressed alpha 2-3SATs. The newly discovered FucT-3 (GDP-Fuc:NeuGc-iLc6-alpha 1-3FucT) from human colon carcinoma (Colo-205) has also been solubilized and separated from other GSL:GLTs. Using a new activity gel-Western blot combined technique, the molecular mass of this FucT-3 was determined to be 105 kDa.

Animals↗