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Biomedical subjects

R Smith

Publications and source records attributed to R Smith.

At least 181 records · Page 10Linked to original sources
PubMed2001

Hepatitis C virus among high and low risk pregnant women in Dundee: unlinked anonymous testing.

OBJECTIVE: To determine the prevalence of the hepatitis C virus among pregnant women, to gauge the non-injecting, particularly sexual, risk of them being hepatitis C virus infected and to assess the potential impact of selective antenatal screening. POPULATION: Antenatal clinic attenders and women undergoing termination of pregnancy in 1997. SETTING: Ninewells Hospital, Dundee. DESIGN: Unlinked anonymous hepatitis C virus antibody testing of residual sera from specimens sent to the virus laboratory for routine serological testing. The results were linked to non-identifying risk information. RESULTS: Overall anti-hepatitis C virus prevalence was 0.6% (23/3,548). Prevalences among injecting drug users, non-injectors who had a sexual partner who injected, and those with neither risk respectively were 41% (7/17), 15% (5/33) and 0.3% (11/3,498). Relative risks for being an injector and a sexual partner of an injector respectively were 131 (95% CI 58-297) and 48 (95% CI 5-32). It is estimated that one of the 18 antenatal clinic attenders gave birth to an infected child. CONCLUSION: Findings suggest that non-injecting partners of injectors may be at considerable risk of acquiring hepatitis C virus sexually. Efforts to promote the use of condoms among injectors and their sexual partners should be increased. Selective anti-hepatitis C virus screening of women who reported high risk behaviour would have failed to detect half the cases. Research to gauge the views of women of childbearing age on anti-hepatitis C virus testing is required.

Adult↗
PubMed2001

Rate of rise in maternal plasma corticotrophin-releasing hormone and its relation to gestational length.

OBJECTIVE: To assess the relationship between rate of increase in maternal plasma corticotrophin-releasing hormone and gestational length. DESIGN: A prospective observational study. SETTING: Department of Obstetrics and Gynaecology, Prince of Wales Hospital, Hong Kong. METHODS: Serial venous samples taken at four to six week intervals from 81 pregnant Chinese subjects were assayed for corticotrophin-releasing hormone concentrations. The investigators responsible for the laboratory assay were blinded to the obstetric outcome. RESULTS: A total of 380 blood samples were taken. Each subject provided three to seven samples (median = 5). Seven of the 81 subjects had preterm delivery. Maternal corticotrophin-releasing hormone levels increased exponentially as gestation advanced. A negative correlation between the rate of rise of logarithmic equivalence of corticotrophin-releasing hormone concentrations (Ln-corticotrophin releasing hormone) per week and the gestational age at delivery was demonstrated (r = -0.45, P < 0.001). The rate of increase of Ln-corticotrophin releasing hormone concentrations per week was also significantly greater for those who delivered preterm before 37 weeks compared with those with uncomplicated term deliveries (0.27 Vs 0.22, P = 0.018). CONCLUSIONS: The rate of increase in maternal plasma corticotrophin-releasing hormone is inversely proportional to gestational length. Results in a Chinese population confirm and extend results from previous caucasian populations. This study provides another piece of evidence on the close link between maternal plasma corticotrophin-releasing hormone and the timing of human parturition. As the hormone is synthesized by the placenta, it supports the suggestion that the human placenta has an important role in determining gestational length.

Adult↗
PubMed2001

Salmonella enterica serovar typhimurium induces cell death in bovine monocyte-derived macrophages by early sipB-dependent and delayed sipB-independent mechanisms.

It was previously demonstrated that Salmonella enterica serovar Typhimurium induces cell death with features of apoptosis in murine macrophages. Mice infected with Salmonella serovar Typhimurium develop systemic disease without diarrhea, whereas the infection in cattle and in humans is localized and characterized by diarrhea. Considering these clinical disease expression differences between mice and cattle, we investigated whether serovar Typhimurium is cytotoxic for bovine macrophages. Macrophages infected with serovar Typhimurium grown in the logarithmic phase quickly underwent cell death. Macrophages infected with stationary-phase cultures or with a mutant lacking sipB underwent no immediate cell death but did develop delayed cytotoxicity, undergoing cell death between 12 and 18 h postinfection. Both pathways were temporarily blocked by the general caspase inhibitor Z-VAD-Fmk and by the caspase 1 inhibitor Z-YVAD-Fmk. Comparisons of macrophages from cattle naturally resistant or susceptible to intracellular pathogens indicated no differences between these two genetic backgrounds in terms of susceptibility to serovar Typhimurium-induced cell death. We conclude that Salmonella serovar Typhimurium induces cell death in bovine macrophages by two distinct mechanisms, early sipB-mediated and delayed sipB-independent mechanisms.

Amino Acid Chloromethyl Ketones↗
PubMed2001

RNA trafficking signals in human immunodeficiency virus type 1.

Intracellular trafficking of retroviral RNAs is a potential mechanism to target viral gene expression to specific regions of infected cells. Here we show that the human immunodeficiency virus type 1 (HIV-1) genome contains two sequences similar to the hnRNP A2 response element (A2RE), a cis-acting RNA trafficking sequence that binds to the trans-acting trafficking factor, hnRNP A2, and mediates a specific RNA trafficking pathway characterized extensively in oligodendrocytes. The two HIV-1 sequences, designated A2RE-1, within the major homology region of the gag gene, and A2RE-2, in a region of overlap between the vpr and tat genes, both bind to hnRNP A2 in vitro and are necessary and sufficient for RNA transport in oligodendrocytes in vivo. A single base change (A8G) in either sequence reduces hnRNP A2 binding and, in the case of A2RE-2, inhibits RNA transport. A2RE-mediated RNA transport is microtubule and hnRNP A2 dependent. Differentially labelled gag and vpr RNAs, containing A2RE-1 and A2RE-2, respectively, coassemble into the same RNA trafficking granules and are cotransported to the periphery of the cell. tat RNA, although it contains A2RE-2, is not transported as efficiently as vpr RNA. An A2RE/hnRNP A2-mediated trafficking pathway for HIV RNA is proposed, and the role of RNA trafficking in targeting HIV gene expression is discussed.

Animals↗
PubMed2001

Crystalline silica exposure and lung cancer mortality in diatomaceous earth industry workers: a quantitative risk assessment.

OBJECTIVE: To use various exposure-response models to estimate the risk of mortality from lung cancer due to occupational exposure to respirable crystalline silica dust. METHODS: Data from a cohort mortality study of 2342 white male California diatomaceous earth mining and processing workers exposed to crystalline silica dust (mainly cristobalite) were reanalyzed with Poisson regression and Cox's proportional hazards models. Internal and external adjustments were used to control for potential confounding from the effects of time since first observation, calendar time, age, and Hispanic ethnicity. Cubic smoothing spline models were used to assess the fit of the models. Exposures were lagged by 10 years. Evaluations of the fit of the models were performed by comparing their deviances. Lifetime risks of lung cancer were estimated up to age 85 with an actuarial approach that accounted for competing causes of death. RESULTS: Exposure to respirable crystalline silica dust was a significant predictor (p<0.05) in nearly all of the models evaluated and the linear relative rate model with a 10 year exposure lag seemed to give the best fit in the Poisson regression analysis. For those who died of lung cancer the linear relative rate model predicted rate ratios for mortality from lung cancer of about 1.6 for the mean cumulative exposure to respirable silica compared with no exposure. The excess lifetime risk (to age 85) of mortality from lung cancer for white men exposed for 45 years and with a 10 year lag period at the current Occupational Safety and Health Administration (OSHA) standard of about 0.05 mg/m(3) for respirable cristobalite dust is 19/1000 (95% confidence interval (95% CI) 5/1000 to 46/1000). CONCLUSIONS: There was a significant risk of mortality from lung cancer that increased with cumulative exposure to respirable crystalline silica dust. The predicted number of deaths from lung cancer suggests that current occupational health standards may not be adequately protecting workers from the risk of lung cancer.

Adult↗
PubMed2001

Quantum mechanical quantitative structure activity relationships to avoid mutagenicity in dental monomers.

The objective of this study was to identify through quantum mechanical quantitative structure activity relationships (Q-QSARs) chemical structures in dental monomers that influence their mutagenicity. AMPAC, a semiempirical computer program that provides quantum mechanical information for chemical structures, was applied to three series of reference chemicals: a set of methacrylates, a set of aromatic and a set of aliphatic epoxy compounds. QSAR models were developed using this chemical information together with mutagenicity data (Salmonella TA 100, Ames Test). CODESSA, a QSAR program that calculates quantum chemical descriptors from information generated by AMPAC and statistically matches these descriptors with observed biological properties was used. QSARs were developed which had r2 values exceeding 0.90 for each study series. These QSARs were used to accurately predict the mutagenicity of BISGMA. a monomer commonly used in dentistry, and two epoxy monomers with developing use in dentistry, GY-281 and UVR-6105. The Q-QSAR quantum mechanical descriptors correctly predicted the level of mutagenicity for all three compounds. The descriptors in the correlation equation pointed to components of structure that may contribute to mutagenesis. The QSARs also provided 'dose windows' for testing mutagenicity, circumventing the need for extensive dose exploration in the laboratory. The Q-QSAR method promises an approach for biomaterials scientists to predict and avoid mutagenicity from the chemicals used in new biomaterial designs.

Dental Enamel↗
PubMed2001

Books@Ovid: a product review.

Books@Ovid is a full-text database of clinical textbooks published by Lippincott, Williams and Wilkins, and McGraw-Hill. It is distributed by Ovid Technologies. In addition to discussing the search environment for Books@Ovid, this paper discusses its online help, indexes, and content, in terms of both coverage and updates. How this product competes with its counterparts in print is also treated in the discussion.

Databases as Topic↗
PubMed2001

Corticotrophin-releasing hormone and human parturition.

Corticotrophin-releasing hormone (CRH), the hypothalamic peptide that controls function of the pituitary-adrenal axis in response to stress, is expressed in abundance in the human placenta and is present in high concentrations in maternal and fetal plasma during late pregnancy. A number of lines of evidence now imply a role for this hormone in the control of parturition and fetal maturation in humans. It has been proposed that CRH, through interactions with oestrogen, adrenal steroids, prostaglandins and oxytocin, establishes positive-feedback loops that initiate parturition and labour. Excessive production of placental CRH has also been linked to preterm labour. However, there are a number of significant gaps in our knowledge of the function of this peptide in pregnancy. This review examines current evidence regarding the putative role of CRH in human parturition.

Animals↗
PubMed2001

A comparison of the effects of local analgesic solution in the navicular bursa of horses with lameness caused by solar toe or solar heel pain.

We hypothesised that analgesia of the navicular bursa is not selective for the navicular apparatus; and that solar pain in some horses can be temporarily abolished or attenuated by analgesia of the navicular bursa. To test this hypothesis, we caused lameness in horses by inducing pain in the dorsal margin or the angles of the sole and then evaluated the ability of a local analgesic solution administered into the navicular bursa to attenuate lameness. The response of horses with solar pain in the dorsal or palmar aspect of the foot to 3.5 ml local analgesic solution administered into the navicular bursa was examined. Lameness was induced in 6 horses by creating solar pain in the dorsal aspect of one forefoot and, at another time, the palmar aspect of the other forefoot, with set-screws inserted into a custom-made shoe. Horses were videotaped trotting before and after application of set-screws and after administering 3.5 ml local analgesic solution into the navicular bursa. Lameness scores were assigned by examining videotaped gaits. Scores were significantly lower (P<0.05) for all horses with set-screws applied to the dorsal margin of the sole after administration of local analgesic solution into the navicular bursa. In conclusion, analgesia of the navicular bursa was less effective in desensitising the angles of the sole than in desensitising the dorsal margin of the sole. Pain arising from the sole should not be excluded as a cause of lameness when lameness is attenuated by analgesia of the navicular bursa.

Anesthetics, Local↗
PubMed2001

A comparison of the effects of two volumes of local analgesic solution in the distal interphalangeal joint of horses with lameness caused by solar toe or solar heel pain.

The response of horses, with solar pain in the dorsal or palmar aspect of the foot, to 6 or 10 ml local analgesic solution administered into the distal interphalangeal (DIP) joint was examined. Lameness was induced in 7 horses by creating solar pain in the dorsal aspect of one forefoot and, at another time, the palmar aspect of the other forefoot with set-screws inserted into a custom-made shoe. Horses were videotaped trotting before and after application of set-screws and, in separate trials, after 6 or 10 ml local analgesic solution was administered into the DIP joint. Lameness scores were assigned by examining videotaped gaits. Scores were significantly lower (P < 0.05) for horses with set-screws applied to the angles of the sole and receiving 10 ml, but not 6 ml, local analgesic solution into the DIP joint. Scores were significantly lower (P < 0.05) for all horses with set-screws in the dorsal margin of the sole receiving either volume of local analgesic solution. Analgesia of the DIP joint was less effective in desensitising the angles of the sole than in desensitising the dorsal margin of the sole, and 10 ml local analgesic solution was more effective than 6 ml in desensitising these regions. The response of horses with solar pain to local analgesic solution in the DIP joint was influenced by the volume administered and the region of sole affected.

Analgesia↗
PubMed2001

Characterization of urocortin in human pregnancy.

OBJECTIVE: To examine whether urocortin is produced locally to regulate utero-placental vascular tone during pregnancy. METHODS: We examined the distribution of urocortin in human placenta, fetal membranes and uterine tissue at term in the presence and absence of labor using a urocortin antibody produced in our laboratory and the immunoperoxidase staining method. Subsequently, we tested urocortin secretion from chorio-decidual cells in vitro using an immunoblot technique. Then, we tested whether urocortin is present in maternal plasma throughout gestation using a radioimmunoassay. A Sephadex G-50 column was used to examine whether immunoreactive urocortin (IR-urocortin) in maternal plasma is the same as synthetic urocortin. RESULTS: IR-urocortin was observed in vascular smooth muscle of myometrium decidual stromal cells, syncytiotrophoblast and amnion epithelium. No differences in staining intensity for urocortin were detected between tissues obtained in the absence or presence of labor. Staining intensity for IR-urocortin was greatest in the decidua, suggesting this may be the main site of urocortin production. Positive staining for urocortin was observed in 40% of chorio-decidual cells with 34% of these cells secreting urocortin under basal conditions. Urocortin was detectable in maternal plasma from 16 weeks gestation and concentrations did not change as gestation progressed. IR-urocortin in the maternal plasma eluted from a Sephadex G-50 column at the same site as synthetic urocortin and had a calculated retention co-efficient of 0.44. CONCLUSION: This study indicates that urocortin is produced by the decidua during human pregnancy and is detectable in maternal plasma. These data are consistent with the hypothesis that urocortin is produced locally by the decidua and may act to regulate utero-placental blood flow.

Animals↗
PubMed2001

Multiskilling: a course to increase multidisciplinary skills in future dietetics professionals.

Multiskilling, or cross training, can enable students to gain the knowledge and skills to become proficient practitioners. This article describes a multiskilling course designed to increase dietetics students' awareness of diverse health-related skills and to enhance their ability to develop new skills for future practice. Allied health professionals lectured on and demonstrated cardiopulmonary resuscitation, stress management, dysphagia and swallowing evaluation, adaptive feeding devices, exercise testing, monitoring of vital signs, and multi-department management. Results of course-evaluation surveys distributed to the students (n = 12) on the last day were extremely positive, with an overall mean rating of 1.07 on a scale of 1 (highest) to 4, indicating that the course included appropriate information, assignments, and evaluation mechanisms. This study provides preliminary evidence that a didactic experience can enhance students' awareness of other allied health professions. Through "hands-on" activities, students can become more confident in their knowledge and in the skills needed to function effectively as members and leaders of health care teams.

Competency-Based Education↗
PubMed2001

Representations of mind: C. S. Sherrington and scientific opinion, c. 1930-1950.

Recent writers in the brain sciences and the philosophy of mind contrast modern biological theories of consciousness with a mind-body dualism supposedly dominant half-a-century ago which they regard as scientifically sterile. Reference to C. S. Sherrington often signals the rejected dualism. This paper re-examines Sherrington's highly qualified position and links it to the arguments of British scientists for whom he was a figurehead in the 1930s and 1940s. I interpret the mind-body literature as ancillary to debates about cultural values. From this perspective, dualism represents a defense of a threatened conservative culture. Dismissal of scientists' supposed "dualism" does little to illuminate the tension in their thought between defense of values traditionally associated with mind and hope for an integrated mind-body science. This leads to comments on Sherrington's own concept of integration. The conclusion relates these points to the new research in the brain sciences evident by the end of the 1940s.

Brain↗
PubMed2001

Protecting genetic materials and genetic information: a case study of Guthrie Cards in Victoria.

The authors are privileged to have been provided with correspondence about a dispute over the ongoing storage of genetic material (as Guthrie Cards) in Victoria. The correspondence details confusion over the roles of government and the private sector service provider in accounting for the storage, use and destruction of these stored genetic materials collected as part of a government public health program. The purpose in publishing this account is to highlight the present inadequacies in current practices and the ongoing potential for a crisis in the management of collected genetic materials through a lack of appropriate regulation, transparency and accountability. The article suggests measures to remedy some of the existing inadequacies in contractual arrangements and recommends that the government retain ownership and control of both the genetic materials and the derived information to ensure some accountability in the present legal environment.

Contract Services↗
PubMed2001

An audit of the investigation and use of anti-D immunoglobulin prophylaxis in Tayside.

OBJECTIVES: To audit the implementation of national guidelines on the investigation and management of RhD disease in Tayside. SETTING: Tayside region. DESIGN: An eight month retrospective audit. RESULTS: Two hundred and eighty eight completed pregnancies in RhD negative women were observed from a total of 1879 deliveries. Of these, 120 RhD negative and 169 RhD positive babies were delivered from women who had not previously been sensitised. At delivery, anti-D was used appropriately in all cases. Of those assessed to require anti-D (n = 168), 91% received it within 24 hours of delivery. In 59 RhD negative subjects, 75 potential sensitising events occurred antenatally. In 45 of these, the event occurred after 20 weeks gestation and 44 received appropriate anti-D. In 11 (23.7%) of these, no foetomaternal haemorrhage assessment was carried out. CONCLUSION: Despite a significant increase in awareness of antenatal prophylaxis since a previous audit in the region, there is still a significant failure to request FMH assessments following potential antenatal sensitising episodes and after delivery. During the audit period, an EDTA plasma gell-based antibody detection system was commissioned in the region. This has allowed the introduction of internal laboratory referral for FMH assessment. This has allowed accurate knowledge on the possible occurrence of FMH at delivery, but has not had a significant impact on antenatal events.

Female↗