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Biomedical subjects

S Thomas

Publications and source records attributed to S Thomas.

At least 379 records · Page 21Linked to original sources
PubMed1997

Evaluation of the role of syringing prior to cataract surgery.

Patients for cataract surgery in India routinely undergo preoperative syringing to rule out chronic dacryocystitis. We determined the sensitivity and specificity of the clinical test of regurgitation on pressure over the lacrimal sac (ROPLAS) as a screening test for chronic dacryocystitis and compared it to syringing. 621 consecutive outpatients who needed syringing for various reasons (including 318 who had routine syringing prior to cataract surgery) were examined in a masked manner for regurgitation on pressure over the lacrimal sac. They then underwent syringing by a trained (masked) observer. The sensitivity and specificity of ROPLAS were 93.2% and 99.3%, respectively. Using a 6.6% prevalence of chronic dacryocystitis (the prevalence in our cataract population), the negative predictive value of the test was 99.5%. In the presence of regurgitation of pressure over the sac, the high specificity of ROPLAS confirms chronic dacryocystitis. In view of the opportunity costs, when ROPLAS is negative, preoperative syringing in cataract is perhaps unnecessary, unless the findings are equivocal or the index of suspicion for chronic dacryocystitis is very high.

Cataract↗
PubMed1996

A longitudinal study of human age-related ribosomal RNA gene activity as detected by silver-stained NORs.

The relative frequencies of silver-stained nucleolar organizing regions (Ag-NORs) as a function of age have been analyzed in skin fibroblasts derived from eight adult individuals participating in the Gerontology Research Center (GRO) Longitudinal Study, NIA, Baltimore, MD. Since silver staining of NORs is correlated with rRNA gene activity, we used this cytological method to examine the pattern of rRNA gene activity in specific individuals, each at two different ages. Our results show that the average number of Ag-NORs/cell decreases significantly with advancing age of each individual, presumably indicating a general pattern of age-related decline/alteration in rRNA gene activity and this pattern is individual-specific. The findings of our longitudinal study is consistent with the results of previous cross-sectional (population) studies on rRNA gene activity as detected by Ag-NORs. However, it appears that the relative rate in the age-related decline of rRNA gene activity, as evidenced by lower Ag-NOR frequencies with age, is variable from person to person.

Adult↗
PubMed1996

Taxing patients.

Explore the source record for details and available documents.

Humans↗
PubMed1996

Expression of recombinant rat myo-inositol 1,4,5-trisphosphate 3-kinase B suggests a regulatory role for its N-terminus.

We have expressed rat myo-inositol 1,4,5-trisphosphate (IP3) 3-kinase B as both a full-length, recombinant, non-fusion protein and a full-length, recombinant, fusion protein with maltose-binding protein (MBP) in Escherichia coli. The fusion protein with MBP is soluble, binds calmodulin and is enzymically active whereas the non-fusion protein is insoluble and does not bind calmodulin unless co-expressed with bacterial chaperone proteins (either GroES and GroEL, or DnaK, DnaJ and GrpE). However, soluble, calmodulin-binding non-fusion IP3 3-kinase B is enzymically inactive. The catalytic domain of the enzyme has previously been shown to reside near the C-terminus; the results we present suggest an auto-regulatory role for the N-terminus.

ATP-Binding Cassette Transporters↗
PubMed1996

Cardiology. Managing equipment.

As nurses have become involved in more and more highly technological procedures and with the risk of possible litigation associated with potential cross contamination from the reuse of disposable equipment, the management and safe use of equipment are playing an increasingly important role in all spheres of cardiology and cardiac care.

Cardiology↗
PubMed1996

Design of metabolic control for large flux changes.

Metabolic Control Analysis has invalidated many traditional biochemical concepts of control, in particular the rate-limiting step. However, it has not been used to question the mechanisms by which pathway flux is thought to be controlled, such as the action of allosteric effectors or of covalent modification mechanisms. Here we use Control Analysis and computer simulation to examine the response of pathway segments to change in flux imposed by action on an enzyme outside the segment. Whether these segments contain near-equilibrium enzyme-catalysed reactions, cooperative enzymes, feedforward activation loops or feedback inhibition loops, their responses are significantly different from those observed in vivo. In particular, they do not exhibit the remarkable degrees of metabolite homoeostasis during large flux changes that have frequently been observed experimentally. On the other hand, near-constant levels of metabolites in spite of large changes of flux are consistent with our recent proposal that multi-site modulation--simultaneous activation of many pathway steps-is the normal method by which metabolism is controlled.

Animals↗
PubMed1996

Age-related aneuploidy analysis of human blood cells in vivo by fluorescence in situ hybridization (FISH).

All prior studies on human age-related chromosomal analysis were done using only metaphase figures derived from lymphocyte cultures in vitro. However, we believe that this procedure may provide only partial information, since the chromosomal abnormalities probably hidden in non-dividing and/or terminally differentiated leukocytes will not be detected by this method. We, therefore, have attempted to analyze the nature and extent of chromosome-specific aneuploidy at interphase by fluorescence in situ hybridization (FISH) in differentiated myeloid cells in vivo derived from various age-group people. Our data from an analysis of 30,032 cells derived from 12 healthy donors indicate that there is an increase in the mean percentages of myeloid cells with chromosome-specific aneuploidy in the older groups as opposed to that of the younger groups. This increase is applicable to all the three cell types examined (promyelocytes, metamyelocytes and polymorphs). In both the younger and older females, the relatively higher mean frequencies of cells with aneuploidy were noted for chromosome nos. 4, 6 and the X, whereas the lowest mean frequencies of cells with aneuploidy were consistently observed for chromosome no. 3. In the younger and older male donors, similar to the female donors except the X chromosome the higher percentages of aneuploid cells were observed for chromosome nos. 4 and 6 whereas the lowest mean frequencies of aneuploid cells were noted for chromosome no. 3. Among the five autosomes studied, chromosome no. 3 consistently yielded the lowest frequency of aneuploidy in all the three cell types derived from both the younger and older groups of males and females. This could presumably mean that the maintenance of a very high frequency of cells with disomy for chromosome no. 3 might be more beneficial for the process of survival and/or differentiation of myeloid cells as compared to that of other autosomes such as chromosome nos. 4 and 6. Among the five autosomes studied, chromosome no. I exhibited the highest rate of increment in the aneuploidy values of both males and females with advancing age.

Adult↗
PubMed1996

Re-engineering a pharmacy work system and layout to facilitate patient counseling.

The development and evaluation of a new work system and facility design for a chain of community pharmacies are described. A new work system was developed to optimize utilization of pharmacist and technician time and allow the pharmacy to increase patient counseling without adding personnel. In the new system, pharmacists would review prescriptions, check technicians' work, and dispense prescriptions, counseling patients as needed; technicians would enter prescriptions into the pharmacy computer and fill them. The existing work system and design were evaluated in June and July of 1992 by observing, classifying, and recording activities of pharmacy personnel three days per week at six pharmacies in the chain. Pharmacy designs that would work with the new work system were created by a university design class after consultation with representatives of the pharmacy chain and the university's college of pharmacy. The pharmacy chain selected one design, and a detailed floor plan and specifications were created. To test how the new design and system would work at each of the six test pharmacies, a computer simulation program was developed and verified by using the data collected on the existing pharmacy operations. Computer simulation showed that, with the new design and system, increasing patient counseling would increase patient waiting time slightly but would not require additional personnel. The layout and work system in a chain of community pharmacies were redesigned to facilitate patient counseling and make the best use of employee time.

Community Pharmacy Services↗