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Biomedical subjects

S Brown

Publications and source records attributed to S Brown.

At least 325 records · Page 18Linked to original sources
PubMed1997

Epilepsy, the law and the media.

It is generally accepted that the media exerts a powerful influence over what the general public feels and believes. This study examined references to epilepsy and the law found in general media communications from January 1993 to December 1994 in the UK. These articles were extracted from general audience material mainly newspapers and magazines. Any article which referred to the legal aspects of epilepsy were then selected. These included those relating to legislation e.g. driving, state benefits and those relating to criminal law e.g. convictions. The reports were analyzed in terms of type of communication, space allotted, circulation and terminology used both in the title and the general text. An attempt was also made to classify the general image which the article portrayed. It is accepted that content analysis itself provides no direct data about the nature of the communicator, the audience or its effects and this method has cautiously been used to classify and describe the manifest content of the method of communication. The study concludes that although it is encouraging that legal aspects of epilepsy are receiving media attention, this attention could be used in a more positive manner in promoting awareness, rather than many of the cases examined which appeared to use negative images in order to pander to popular audience appeal.

Adult↗
PubMed1997

Women's views of different models of antenatal care in Victoria, Australia.

BACKGROUND: This study assessed women's views of care in pregnancy, contrasting the experiences and satisfaction of women using different models of care in Victoria, Australia. METHODS: A statewide postal survey of women who gave birth during a 2-week period in 1993 was carried out 6 to 7 months after birth. RESULTS: Of 1336 women, 62.5 percent responded, and of these, 62.4 percent rated their antenatal care as very good, 27.7 percent as good, 8.2 percent as mixed, and 1.8 percent as poor or very poor. Although social factors, obstetric factors, and model of care had significant associations with satisfaction in univariate analyses, only model of care, mother's country of birth, and medical risk remained significant in a multivariate analysis using logistic regression. Women were most likely to be satisfied when antenatal care was provided by an obstetrician in private practice or a birth center. When comparisons were restricted to options available to women without private health insurance, using public hospital clinics as the baseline in a multivariate analysis, women were significantly more likely to be satisfied with birth center care, and significantly less likely to be satisfied with shared care. Contributing factors were waiting times, staff seeming rushed, and lack of continuity of caregiver. CONCLUSION: The expansion of shared antenatal care has not succeeded in improving satisfaction with antenatal care for women in the public health care sector.

Adolescent↗
PubMed1997

9p21 deletions in primary melanoma.

Formalin-fixed, paraffin-embedded primary melanoma biopsies were evaluated for evidence of genomic loss on the short arm of chromosome 9 using microsatellite PCR assays for the D9S157, D9S161 and D9S171 loci. Paired normal and tumor DNA was extracted from the same block for comparison of microsatellite marker patterns. Some detectable abnormality was seen in at least one of these loci in 15 of 44 evaluable specimens (34%). Homozygous deletions were detectable at these loci in 8 of 44 informative specimens (18%) and hemizygous deletions were seen in 11 of 44 informative specimens (25%). Deletions at 9p were more likely to be found as primary tumor thickness increased (p < 0.05). This evidence supports the concept that 9p21 deletions are involved in primary sporadic melanomas, and that 9p deletions are not solely an in vitro phenomenon.

Alleles↗
PubMed1997

UV irradiation of a B-cell hybridoma increases expression of alkaline phosphatase: involvement in apoptosis.

Expression of alkaline phosphatase (APase) by 7TD1 B-cell hybridoma was amplified by ultraviolet irradiation; cell growth was inhibited and cell death by apoptosis was increased. Irradiation induced high levels of APase activity in cycling as well as in apoptotic cells. In contrast, APase activity faded with time in nonirradiated cells and was no longer expressed in spontaneous apoptotic cells appearing after several days in culture. This was demonstrated by cell morphology, DNA fragmentation, and flow cytometry after simultaneous staining of DNA with Hoechst 33342 and APase with naphthol AS-TR phosphate--fast red RC fluorescent reagent. Levamisole, a specific inhibitor of APase activity, almost totally abrogated apoptosis induced by ultraviolet irradiation at doses that failed to affect 7TD1 cell survival. These data suggest that APase could play a role in the signalling cascade that mediates apoptosis in irradiated cells.

Alkaline Phosphatase↗
PubMed1996

Refined mapping of the Usher syndrome type III locus on chromosome 3, exclusion of candidate genes, and identification of the putative mouse homologous region.

A locus for Usher syndrome type III (USH3; MIM No. 276902) was recently assigned to a 5-cM region on chromosome 3q. We constructed a yeast artificial chromosome contig that allowed us to position novel polymorphisms in the region. These were typed in a total of 32 pedigrees from a geographically isolated Finnish founder population in which a putative single ancestral USH3 mutation segregates. A multipoint linkage analysis assigned USH3 to a 4-cM region between D3S1555 and a novel marker D3S3625. By analysis of linkage disequilibrium and historical recombinations in 77 USH3 chromosomes, the location of the Finnish USH3 mutation could be narrowed to an approximately 1-cM interval between the markers D3S1299 and D3S3625. A gene for profilin-2 (PFN2) was mapped in the vicinity and excluded as a candidate for USH3 by sequencing. The putative mouse homolog of PFN2 was mapped to mouse chromosome 3, thus suggesting a localization for the mouse homolog of USH3.

Alleles↗
PubMed1996

Class 3 Hox genes in insects and the origin of zen.

We have cloned, from a beetle and a locust, genes that are homologous to the class 3 Hox genes of vertebrates. Outside the homeobox they share sequence motifs with the Drosophila zerknüllt (zen) and z2 genes, and like zen, are expressed only in extraembryonic membranes. We conclude that the zen genes of Drosophila derive from a Hox class 3 sequence that formed part of the common ancestral Hox cluster, but that in insects this (Hox) gene has lost its role in patterning the anterio-posterior axis of the embryo, and acquired a new function. In the lineage leading to Drosophila, the zen genes have diverged particularly rapidly.

Amino Acid Sequence↗
PubMed1996

Sinefungin and taxol effects on cell cycle and cytoskeleton of Leishmania donovani promastigotes.

Sinefungin is an antibiotic possessing a strong anti-leishmanial activity. Among the most important effects of this molecule on Leishmania donovani promastigotes are morphological modifications and a very rapid and effective inhibition of DNA synthesis. These cells contain a single DNA-rich mitochondrion whose division cycle is coordinated with the nuclear division cycle. We have developed a flow-cytometric procedure based upon mithramycin as fluorochrome that can perform quantitative cell cycle analysis on the nuclear DNA. Cell cycle progression was analyzed to establish that sinefungin irreversibly blocks the promastigotes in early S phase. Sinefungin did not react with stationary cells as they were arrested in G1. Surprisingly, taxol, a microtubule-stabilizing drug, induced the same morphological modifications as sinefungin although it interfered with the G2/M progression. According to immunofluorescence studies, the stable microtubular network is apparently affected neither by taxol nor by sinefungin.

Actins↗
PubMed1996

Flow cytometric analysis of cytosolic pH of mesophyll cell protoplasts from the crabgrass Digitaria sanguinalis.

Phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) is a key enzyme of photosynthesis in C4 plants; it is specifically localized in the cytosol of mesophyll cells and is regulated by a phosphorylation/dephosphorylation process. The light-dependent phosphorylation of PEPC is triggered by an increase in the cytosolic pH (pHc) of mesophyll cell protoplasts. An epifluorescence and confocal microscopy analysis showed that the specific pH probe 2',7'-bis-(2-carboxyethyl)-5-(and-6) carboxyfluorescein, acetoxymethyl ester (BCECF-AM), when used at low concentration, was essentially localized in the protoplast cytosol. By the nigericin null-point method and flow cytometry, the pHc of freshly isolated protoplasts was estimated to be 6.4. To observe the full activity of PEPC kinase and maximal phosphorylation of PEPC in vivo, such protoplast suspensions must first be treated with a permeant weak base. The present report shows that 20 mM NH4Cl raised the final pHc to 7.4. This method can be useful for estimating rapid changes of pHc in plant cells.

Ammonium Chloride↗
PubMed1996

Cytosine arabinoside differentially alters survival and neurite outgrowth of neuronal PC12 cells.

Cytosine arabinoside, a potent antimitotic agent, is used clinically as an anticancer drug with the side effect of severe neurotoxicity. Earlier reports suggested that this agent blocks the signaling pathway of nerve growth factor in sympathetic neurons, which results in neuronal death. The present study demonstrated that neuronal PC12 cells deprived of nerve growth factor showed a decrease of neurite outgrowth, which was not seen in cytosine arabinoside-treated neuronal PC12 cells, suggesting that this agent may not interfere with the part of the NGF signaling pathway that leads to neurite outgrowth. On the other hand, treatment of neuronal PC12 cells with cytosine arabinoside led to a dose- and time-dependent decrease of viability. These results suggest that there is a distinction between the neurite outgrowth and the survival promoting activities of nerve growth factor.

Animals↗
PubMed1996

Effects of Ca and H2O2 added to RPMI on the fretting corrosion of Ti6Al4V.

Titanium and its alloys have demonstrated considerable success in various surgical procedures including orthopedic, dental, and cardiovascular surgery. However, particulate debris from corrosion and wear is present in a considerable quantity in tissue local to the implant. This study evaluated the effect of Ca, since it is present in both serum and bone, and H2O2, since it is produced through local inflammation, on the amount of titanium release. Four sets of Ti6Al4V plates and Ti6Al4V screws were used. Each set was designated to one of four solutions: RPMI (cell culture growth media), RPMI with CaCl2, RPMI with CaCO3, and RPMI with H2O2. A fretter was used to cause corrosion by creating micromotion between two screws and a two-hole plate of Ti6Al4V. After fretting for 72 h, weight loss of the plate and screws and the amount of Ti and vanadium (V) in solution was used to assess the amount of fretting corrosion which had occurred. Results of weight loss and Ti in solution indicated that the presence of H2O2 increased the amount of particulate debris produced in RPMI as compared with RPMI alone. The addition of CaCl2 to RPMI also increased both weight loss and Ti in solution compared with RPMI alone. The addition of CaCO2, however, did not give values significantly different from RPMI alone. Comparison of weight loss and Ti in solution indicated that the increase in fretting corrosion was not different between RPMI with CaCl2 and RPMI with H2O2. The particulate wear debris from the four solutions was black in color and the size of the particulate produced was compared using a Coulter Multisizer. The results indicated that particles produced in the four solutions were not different, with mean values between 1.324 and 1.100 microns, and they were similar in size to the particulate found in tissues surrounding failed total hip replacements. In order to better understand the role of Ca in the fretting corrosion of Ti6Al4V, energy dispersive x-ray analysis (EDXA) using SEM was used to determine elemental composition of one countersink surface of a plate which had been run four times in RPMI with CaCl2. The presence of Ca in the bulk was not significant (% composition < 0.5%). However, Ca was present in two surface particles which were examined at a magnification of 55,000, with a Ca% composition of 63.2% and 19.2%. While results from this study indicate that both soluble Ca(CaCl2) and H2O2 increase the fretting corrosion of Ti6Al4V, the insoluble form of Ca, which would be found in bone and hydroxyapatite, has no effect. These data indicate that it is important to specify the media used in corrosion, dissolution, and elution experiments.

Alloys↗