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Biomedical subjects

R Ray

Publications and source records attributed to R Ray.

At least 145 records · Page 8Linked to original sources
PubMed1994

Stromal tumors of the stomach: prognostic value of the PCNA index.

Reliable indicators of behavior in stromal tumors of the gastrointestinal tract have yet to be elucidated. Aggressive behavior has been associated with large size, hypercellularity, tumor necrosis, nuclear atypia, and high mitotic rate. Recently, new methods of measuring proliferation have been developed that exploit the phenomenon of cell cycle specific protein synthesis. In this study the expression of the S-phase specific nuclear protein proliferating cell nuclear antigen (PCNA) is tested as an indicator of malignancy. Sixteen stromal tumors of the stomach were reviewed for tumor size, cellularity, nuclear atypia, mitotic rate, necrosis, vascular invasion, and predominant cell type. Local recurrence and/or mortality were ascertained with a minimum follow-up of 5 yr. An immunohistochemical assay for PCNA was performed on a paraffin section of tumor and the percentage of positively stained cells ("PCNA index") was determined. Among the nine men and seven women, age 37 to 80 (median 66) yr, two had local recurrences that were treated surgically with no metastases. Only positive resection margin correlated with local recurrence. Two other patients developed distant metastases at 8 and 15 mo and died. Mortality did not correlate with age, sex, size, cellularity, necrosis, cell type, and vascular invasion. High grade nuclear atypia (2/2 versus 1/14, P = 0.02) and high mitotic rate (20.5 versus 5.5 per 40 hpfs, P = 0.01) did correlate with mortality. PCNA index did not correlate with local recurrence, but was sharply higher in fatal cases (6.4 versus 1.2, P = 0.001). Both fatal tumors had PCNA values above 6.0, and all others had values of 4.0 or less. The PCNA index is a proliferative marker that may have prognostic value in gastric stromal tumors.

Adult↗
PubMed1994

Obesity in preschool children: an intervention programme in primary health care in Singapore.

The Programme on Prevention and Management of Obesity in Preschool Children, aged three to six years, was implemented in 17 Primary Health Clinics in November 1991. The study sample comprised 1128 preschool children who qualified to enter the obesity register, using the defined criteria for obesity of 2 standard deviations above the normal weight for height and age. This group was divided into three categories, namely, mildly overweight (120% to below 140%), moderately overweight (140% to below 160%), and severely overweight (above 160%). The severely overweight category was referred to dietitians for follow-up management, while the other two categories were managed by the clinic staff through pre-planned nurse-conducted counselling sessions. In this paper, we analysed the first 1128 preschool children aged three to six years on the Programme with respect to their demographic characteristics; medical conditions; family history of obesity, diabetes, hypertension and ischaemic heart disease; number of siblings and parents' educational and occupational status. The Malay children showed significantly more severe grades of obesity compared to the Chinese and Indian children. A family history of obesity and hypertension among the three groups were significant (P < 0.001). After one year of follow-up with the intervention programme, the following were found: 40.4% (456) of the children improved in their obesity status and 20.2% (228) reached normal status. The severe, moderate and mild categories reduced from 6.3% to 5.9%, 29.3% to 23.2% and 64.4% to 50.7% respectively and was found to be statistically significant (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1993

Induction of peroxisomal fatty acid beta-oxidation and liver fatty acid-binding protein by peroxisome proliferators. Mediation via the cytochrome P-450IVA1 omega-hydroxylase pathway.

Both the enzymes of peroxisomal fatty acid beta-oxidation and the liver fatty acid-binding protein (L-FABP) are induced in the liver by peroxisome proliferators, such as clofibrate (CF), as well as high fat diets. One proposed mechanism for this induction is that it represents an adaptive response to altered intracellular fatty acid fluxes, mediated by dicarboxylic fatty acids formed via the cytochrome P-450IVA1 omega-oxidation pathway. The studies presented in this paper were designed to investigate the role of the products of P-450IVA1 omega-oxidation in the regulation of peroxisomal beta-oxidation and L-FABP. In primary hepatocyte cultures exposed to CF, the increase in P-450IVA1 activity preceded the induction of peroxisomal beta-oxidation and L-FABP. The CF-mediated increases in peroxisomal beta-oxidation and L-FABP, but not P-450IVA1, could be significantly inhibited pretranslationally by concurrent exposure of cultured hepatocytes to inactivators of cytochromes P-450, such as 1-aminobenzotriazole and 10-undecynoic acid. Hexadecanedioic acid, a 16-carbon dicarboxylic fatty acid, that is poorly metabolized in hepatocytes, induced peroxisomal beta-oxidation and L-FABP, but not P-450IVA1, via a pretranslational mechanism that was not inhibited by 1-aminobenzotriazole. Long-chain monocarboxylic acids were without such inducing effect. In further studies, non-beta-oxidizable dicarboxylic acid analogs were found to display greater potency as inducers of peroxisomal beta-oxidation when compared to hexadecanedioic acid. The inducing effects of the dicarboxylic acid analogs were also independent of the P-450 omega-oxidation pathway. The results of these studies suggest that the regulation of peroxisomal beta-oxidation enzymes and L-FABP is mediated, to a significant extent, by poorly metabolized long-chain dicarboxylic acids formed via the P-450IVA1 pathway.

Animals↗
PubMed1993

Quantification and kinetics of 25-hydroxyvitamin D3 by isotope dilution liquid chromatography/thermospray mass spectrometry.

A liquid chromatography/thermospray mass spectrometry method has been developed and used to measure the plasma levels and half-life of 25-hydroxyvitamin D3 in adults. The mean plasma levels of 25-hydroxyvitamin D3 averaged 40 ng ml-1 (n = 4) in summer and 30 ng ml-1 (n = 6) in winter. The method was also used to determine the half-life of serum 25-hydroxyvitamin D3 in subjects maintained on either high or low-fiber diets who had been given an intravenous infusion of (6,19,19-2H3)25-hydroxyvitamin D3 sufficient to label 5% of their estimated body pools. The half-life was determined to be 10.4 days (n = 4), which is approximately 50% of the currently accepted value of 19 days, determined using radiolabeled methods. This difference may be due to kinetic isotope effects arising as a result of the tritiated compounds being labeled at sites that undergo Cyt-P450-catalyzed oxidations.

Adult↗
PubMed1993

Quantitative analysis of mast cells in testicular aspiration cytology smears in azoospermic males.

Quantitative estimation of mast cells was done in testicular aspiration cytology smears of 90 azoospermic males. Cases included normal spermatogenesis (32), Sertoli cell only (38), late maturation arrest (16), and early maturation arrest (4). The pooled number of mast cells in 20 standard fields in Sertoli cell only and late maturation arrest cases were significantly higher than that of normal spermatogenesis (P < .001 and P < .01 respectively). Aggregates of mast cells were found around the seminiferous tubules in Sertoli cell only cases. The findings suggest that increased number of mast cells may be the cause or effect of testicular damage in idiopathic male infertility.

Biopsy, Needle↗
PubMed1993

Microencapsulated human parainfluenza virus induces a protective immune response.

Human parainfluenza type 3 (PI3) virus was incorporated into microspheres composed of a biocompatible and biodegradable DL-lactide and glycolide copolymer. Sera from mice immunized with these microspheres showed an antibody response to the viral glycoproteins and neutralized virus infectivity. The microspheres were also evaluated by intraperitoneal, oral, or intranasal administration to determine their protective efficacy in the hamster. After challenge infection of the intraperitoneally immunized hamsters with live PI3 virus, a significant reduction of virus titers in the respiratory tract was observed, demonstrating the protective efficacy of the microencapsulated viral antigens.

Administration, Intranasal↗
PubMed1993

Comparison of fine needle sampling by capillary action and fine needle aspiration.

Fine needle aspiration (FNA) and non-suction fine needle sampling (FNS) were performed consecutively in 107 lesions from 100 patients. The quality of diagnostic material was assessed using a scoring system based on the cellularity and amount of blood in the smear. The total score in the FNS group was significantly higher (P < 0.05) than that of FNA technique. The FNS procedure is less traumatic and equally cost effective and can be safely undertaken in liver, orbital and thyroid lesions. In lymph nodes, especially in children, FNS gives an excellent cellular yield. However, this procedure can not be advocated in cystic, bony and fibrous lesions.

Biopsy, Needle↗
PubMed1992

Triplex formation prevents Sp1 binding to the dihydrofolate reductase promoter.

The human dihydrofolate reductase (DHFR) promoter sequence contains two consensus binding sites for the Sp1 regulatory protein. We have determined the effect of intermolecular triplex DNA formation on Sp1 binding to the DHFR promoter. The DHFR Sp1 binding site I (-39 to -48 relative to the DHFR transcription start site) demonstrates concentration-dependent triplex formation with a 19-base pair G-rich oligonucleotide (GR19) which is complementary to the polypyrimidine strand. DNase I footprint analysis demonstrates that GR19 forms a DNA triplex structure with the DHFR promoter fragment in a sequence-specific manner. DNase I footprinting analysis also indicates that the orientation of binding of these G-rich oligonucleotides is antiparallel. CR19, a C-rich complementary oligonucleotide, on the other hand, does not form triplex. The DNase I protection pattern of DHFR promoter fragment incubated with both recombinant Sp1 and triplex-forming oligonucleotide suggests that triplex formation prevents Sp1 binding. This is confirmed by gel shift analysis which demonstrates that triplex formation by the Sp1 binding sequences of the DHFR promoter prevents recombinant Sp1 binding in a concentration-dependent manner. These results demonstrate that intermolecular triplex formation prevents regulatory protein binding in a sequence-specific manner.

Base Sequence↗
PubMed1992

Synthesis and anticholinesterase activity of new bispyridinium compounds.

Synthesis of new bis(1-methylpyridinium) compounds containing a 1,4-diacetylbenzene linkage between the pyridinium moieties from commercially available 2-, 3-, and 4-picoline precursors was accomplished via metallation, reaction of the picolyllithium with 1,4-dicyanobenzene, and subsequent quaternization of the resulting bispyridyl compounds. Acetylcholinesterase inhibitory activity was determined colorimetrically with purified electric eel enzyme. Examination of structure-activity relationships indicated that the 3-substituted pyridinium compound is the most potent isomer, followed by the 2-substituted isomer, and that the 4-substituted analogue is the least active.

Animals↗