Search PubMed⌕ Search

Biomedical subjects

A Maitra

Publications and source records attributed to A Maitra.

At least 73 records · Page 4Linked to original sources
PubMed1998

Expression of the RNA component of telomerase during human development and differentiation.

We used a radioactive in situ method to study expression of the RNA component of human telomerase (hTR) during normal human development and differentiation using archival tissues. In embryonic tissues, the highest and most uniform expression was present in undifferentiated neuroepithelium. Expression was stronger in immature epithelium than in accompanying immature mesenchyme. Differentiation of most tissues was accompanied by decreased or absent expression. Except for testis and adrenal, the adult pattern of expression was present by the 10th postnatal week. In adult tissues, high expression was present in the testis (primary spermatocytes and Sertoli cells), moderate expression was present in lymphoid follicles (germinal centers), and weak expression was present in epithelia (regenerative cells) but was absent in the nervous system and mesenchymal derived tissues. Expression in adult tissues was predominantly limited to dividing cells, although certain differentiated postmitotic cells expressed the hTR. Our studies demonstrate the complex interrelationship of hTR expression with human development, differentiation, and cell division.

Adolescent↗
PubMed1997

Size Modulation of Polymeric Nanoparticles under Controlled Dynamics of Microemulsion Droplets

Polyacrylamide nanoparticles of different size (<100 nm) were prepared in reverse micelles under various dynamic conditions of micellar systems. The nanoparticles were always larger than the aqueous core in which they were formed; however, the size of the nanoparticles could be controlled if the interdroplet interaction and coalescence rate in reverse micelles were regulated. Factors such as interfacial rigidity of the droplets, size of the aqueous core, temperature, and concentrations of acrylamide (monomer) and N ,N '-methylenebisacrylamide (crosslinking agent) have a profound effect on the size of nanoparticles. By adjustment of these parameters in reverse micelles, nanoparticles ranging from about 10 to more than 100 nm have been prepared.

Journal Article↗
PubMed1997

School accidents to children: time to act.

OBJECTIVE: To describe the profile of injuries sustained by children in school accidents and suggest preventive measures. DESIGN: A five month prospective study of children attending an urban accident and emergency (A&E) department. SUBJECTS: 500 children who sustained injuries in school due to a variety of activities. RESULTS: 10 and 12 year old pupils suffered most injuries in school grounds/playgrounds, on concrete, or on grass/soil surfaces due to random activities resulting in striking or being struck by objects/persons, tripping or slipping, and sports (mainly football); 65.5% of these activities were not supervised and 67.4% occurred "out of lessons"; 22% sustained fractures or dislocations, 28.2% needed follow up treatment, and 1.4% were admitted. CONCLUSIONS: Injuries to children in school are a cause for concern. Effective preventive measures should concentrate on (a) specific target areas using schemes based on individual school, and (b) establishing a credible system of monitoring of their effectiveness.

Accident Prevention↗
PubMed1997

Comparison of two assays for measuring LDL cholesterol.

The purpose of this study was to evaluate the LipiDirect assay (L-LDL) against the Direct LDL immunoseparation method (D-LDL) and beta quantification (BQ-LDL) for measurement of LDL cholesterol (LDL-C) in patients with normo- and hypertriglyceridemia. Samples from 156 patients [triglyceride (Tg) range 0.61-9.95 g/L] were assayed for LDL-C concentrations with the three methods. An additional seven patients with type III hyperlipidemia and 25 paired sera from fasting and nonfasting individuals also were analyzed by the three methods. Both assays displayed excellent precision. The mean LDL-C value from L-LDL was significantly higher than BQ-LDL and D-LDL in normo- and hypertriglyceridemic samples (P < 0.001). The mean absolute bias of L-LDL vs BQ-LDL was 12.7% for Tg < 4 g/L and 30.6% for Tg > or = 4 g/L, compared with 6.2% and 12.5%, respectively, for D-LDL. L-LDL correctly classified only 68% of patients with LDL-C < 1.30 g/L and 57% of patients with LDL-C between 1.30-1.59 g/L as compared with 98% and 93%, respectively, for D-LDL (P < 0.001). In patients with type III hyperlipidemia, L-LDL had a 130% positive bias with BQ-LDL as compared with a 14% negative bias for D-LDL. With all three methods there were no significant differences between samples from fasting and nonfasting individuals. On the basis of these findings, the D-LDL assay appears to be superior to the L-LDL assay.

Cholesterol, LDL↗
PubMed1996

Novel Taxol formulation: polyvinylpyrrolidone nanoparticle-encapsulated Taxol for drug delivery in cancer therapy.

Taxol is a novel antitumor alkaloid that has shown clinical activity against several tumors. However, due to its low aqueous solubility, Cremophor EL (polyoxyethylated castor oil) and ethanol are used as excipients in the pharmaceutical drug formulations. These agents are implicated in hypersensitivity reactions. Hence the goal of this work was to design a novel Taxol formulation using polymeric nanoparticles to eliminate the Cremophor EL vehicle for drug delivery. Polyvinylpyrrolidone nanoparticles containing Taxol were prepared by a reverse microemulsion method. The size of the nanoparticles as determined by quasielastic light scattering was found to be between 50 and 60 nm. The antitumor effect of Taxol encapsulated nanoparticles was evaluated in B16F10 murine melanoma transplanted in C57B1/6 mice. The in vivo efficacy of Taxol-containing nanoparticles as measured by reduction in tumor volume and increased survival time was significantly greater than that of an equivalent concentration of free Taxol. These results suggest that encapsulation of Taxol in polymeric nanoparticles could be useful in improving its therapeutic efficacy in treatment of solid tumors.

Animals↗
PubMed1995

Regulation of porcine granulosa cell 3-hydroxy-3-methylglutaryl coenzyme A reductase by insulin and insulin-like growth factor I: synergism with follicle-stimulating hormone or protein kinase A agonist.

In species such as the pig and human, gonadal steroidogenesis is believed to be dependent upon the availability of low density lipoprotein (LDL) cholesterol. However, before ovulation, Graafian follicles are impermeant to lipoproteins in the LDL class. Thus, de novo cholesterol biosynthesis via the rate-determining enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase is likely to provide a significant mechanism for generating sterol substrate for steroidogenesis by granulosa cells before follicular rupture. As serum-free monolayer culture of (swine) granulosa cells offers an in vitro model of hormonally responsive HMG-CoA reductase, we generated a (porcine) complementary DNA and homologous complementary RNA to investigate by sensitive and specific ribonuclease protection assay the hormonal regulation of HMG-CoA reductase gene expression in ovarian cells from immature Graafian follicles. Using reverse transcriptase-polymerase chain reaction, we cloned and sequenced a 238-base pair complementary DNA from porcine luteal tissue that encodes the catalytic region of HMG-CoA reductase. GenBank analysis of the DNA sequence homology between the pig and other species showed the greatest concordance with human (88%) and hamster (90%). Solution hybridization/ribonuclease protection analysis of total RNA isolated from serum-free monolayer cultures of porcine granulosa cells revealed that insulin (3 micrograms/ml) increased HMG-CoA messenger RNA (mRNA) concentrations corrected for constitutive 18S ribosomal RNA expression in a time-dependent fashion, with significant effects observed at 12 h and a 6-fold increase by 48 h. Recombinant human insulin-like growth factor I (IGF-I) peptide was able to mimic the action of insulin alone. Neither FSH (100 ng/ml) nor 8-bromo-cAMP (1 mM) had observable effects on HMG-CoA message accumulation at any time point studied. However, the combined action of either FSH and insulin or 8-bromo-cAMP and insulin resulted in synergistic increases in reductase mRNA by 31- and 17-fold, respectively. To assess the possible feedback effects of sterol on HMG-CoA gene expression, granulosa cells were treated with LDL. At physiological concentrations, LDL suppressed basal expression of HMG-CoA mRNA to levels below the control value. In addition, LDL inhibited insulin-stimulated HMG-CoA mRNA accumulation by 84% as well as the synergistic effects of insulin and FSH (by 94%) and of insulin and 8-bromo-cAMP (by 93%). We conclude that insulin alone or in combination with FSH or cAMP augments the accumulation of HMG-CoA reductase mRNA in ovarian (granulosa) cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1995

Activity and stability of Bacillus cereus penicillinase entrapped in aerosol OT reverse micelles.

The kinetics of enzyme catalyzed hydrolysis of penicillin G and stability of the enzyme alpha-penicillinase, entrapped in aerosol OT reverse micellar droplets have been investigated spectrophotometrically. Various physical parameters, such as, water pool size (related to Wo), pH and temperature, were optimized for maximum activity of penicillinase in water/aerosol OT/isooctane reverse micelles. The enzyme showed maximum activity of Wo - 14 and pH, 7.0. At any temperature the enzyme was to be more active in reverse micelles than in aqueous solution. At optimum conditions of Wo, pH and temperature the enzyme was 100% more active in reverse micelles than its maximum activity in aqueous solution. In both the systems, the activity starts falling at and above 25 degrees C. CD Spectral studies showed that the enzyme in reverse micelles possesses more helical structure than it has in aqueous solution and at the optimum conditions in which it showed maximum activity, the alpha-helicity was also maximum. The enzyme was very stable in reverse micelles at and above room temperature compared to the same in aqueous solution.

Bacillus cereus↗
PubMed1993

The conservative treatment of mallet finger with a simple splint: a case report.

Sixty patients with mallet finger deformity were randomly treated with either a Stack or a custom-made padded aluminium alloy malleable finger splint. Both splints were equally effective in correcting the deformity but the aluminium alloy splint was able to be fitted to a wider variety of finger shapes and sizes and caused significantly fewer skin complications.

Adolescent↗
PubMed1993

Universal precautions--a critical review.

The route of HIV transmission are now well defined. For health care workers the major occupational risk is from parenteral exposure to infected blood or other body fluids. To prevent such exposures, it would be prudent for HCWs to assume that all patients are potentially infected and a set of precautions applicable universally be followed in contacts with all patients. The provisions of "Universal Precautions" apply to blood, CSF, genital secretions and all body fluids. It is essential that barrier protection and washing of hands be practiced, body fluids be handled with care, correct sterilization and disinfection procedures be followed and a suitable system of waste disposal be evolved. Although the Universal Precautions have been useful in abating some of the more extreme behavior associated with treating AIDS patients and in establishing a rational approach to infection control, some of the recommendations have not been found to be efficacious or cost effective. Preventive measures recommend on the basis of demonstrated efficacy and aimed at routes of exposure that represent true risk are needed. The risks for occupational infection with blood borne pathogens have been a source of concern for health care workers (HCWs) because of their frequent and often substantial exposure to patient blood and body fluids. HCWs have long been identified as a group "at risk" for occupationally acquired Hepatitis B infection. With the development of acquired immunodeficiency syndrome (AIDS) epidemic, both HCWs and policy makers have become increasingly concerned about occupational risk from blood borne infections.(ABSTRACT TRUNCATED AT 250 WORDS)

Gloves, Protective↗
PubMed1992

Patient satisfaction in an urban accident and emergency department.

The aim of this study was to assess patients' opinions about their experience of attending an urban Accident and Emergency department. They were given a questionnaire designed to demonstrate any shortcomings in the delivery of care which required corrective actions. Just over half (50.8%) the patients responded, 411 (95%) of whom recorded satisfaction with the outcome of their visit (P = 0.0001). There was significant correlation between patient satisfaction and waiting time to see the doctor (P = 0.003), the doctor's explanation about management (P = 0.02), and total time spent in the department (P = 0.01). A total of 120 patients (27.8%) did not receive any explanation from the nurse about what was going to happen, and 267 (61.6%) received no information about possible delay. These factors did not significantly influence patients' satisfaction with the outcome, but they need to be addressed as they will obviously lead to an improved service.

Adolescent↗
PubMed1992

An audit of trauma deaths in Newcastle upon Tyne.

The TRISS methodology was applied to identify unexpected trauma deaths during a one-year period. Out of a total of 104 deaths, 50 were hospital deaths (M = 0.6837). Twelve (27%) of these deaths were judged to be unexpected, ie, had a probability of survival (Ps) > or = 0.50 (Z = +4.80). Those deaths deemed to be unexpected were subject to further analysis. The implications of these findings are discussed.

Adolescent↗
PubMed1990

Double-blind, randomized, controlled clinical trial of norfloxacin for cholera.

In a double-blind, randomized clinical trial with 78 adults with acute watery diarrhea and severe dehydration, 37 subjects were positive for Vibrio cholerae. In conjunction with rehydration therapy, 13 patients received norfloxacin, 12 received trimethoprim-sulfamethoxazole (TMP-SMX), and 12 received a placebo. Norfloxacin was superior to TMP-SMX and to the placebo in reducing stool output, duration of diarrhea, fluid requirements, and vibrio excretion. TMP-SMX was no better than the placebo.

Adult↗
PubMed1990

Displaced boxers' fractures: a simple and effective method of external splintage.

Forty patients with fractures of the fifth metacarpal neck (boxers' fractures) having a volar angulation of 30 degrees or more were treated by closed reduction and external immobilisation. A combination of malleable aluminium alloy splint and plaster of Paris cast was used. The results show a significant improvement in fracture angulation after reduction and at follow-up (3/5 weeks) using this form of external splintage. There were no complications. Our results compare favourably with those of other recently published series. We advocate the use of this method of treatment for these fractures with significant volar angulation.

Adolescent↗