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Biomedical subjects

J Melville

Publications and source records attributed to J Melville.

14 recordsLinked to original sources
PubMed2003

Psychosocial impact of serological diagnosis of herpes simplex virus type 2: a qualitative assessment.

OBJECTIVES: To assess the emotional and psychosocial responses to a serological diagnosis of HSV-2 infection in individuals without previous history of genital herpes. METHODS: 24 individuals who had a positive HSV-2 serology by western blot and no clinical history of disease were recruited from four clinics (sexually transmitted disease, maternal and infant care, family medicine, and virology research) over a 10 month period. In-depth qualitative interviews were conducted to elicit an individual's responses to the HSV-2 diagnosis. RESULTS: Three categories of themes were identified from the interviews. Short term emotional responses included surprise, denial, confusion, distress, sadness, disappointment, and relief to know. Short term psychosocial responses included fear of telling sex partners, anger at the source partner, guilt about acquiring or transmitting, and concern about transmitting to a child. Perceived ongoing responses included fear of telling future partners, concern about transmitting to a sex partner, feeling sexually undesirable, feeling socially stigmatised, feeling like "damaged goods," sex avoidance due to social responsibility, fear of transmitting to a newborn, and relationship concerns relating to the diagnosis. CONCLUSIONS: Individuals exhibit strong emotional and psychosocial responses to a serological diagnosis of HSV-2 infection. Many of the negative responses may be time limited and influenced by factors that are potentially amenable to counselling.

Adult↗
PubMed2001

A molecular phylogenetic study of ecological diversification in the Australian lizard genus Ctenophorus.

We present phylogenetic analyses of the lizard genus Ctenophorus using 1,639 aligned positions of mitochondrial DNA sequences containing 799 parsimony-informative characters for samples of 22 species of Ctenophorus and 12 additional Australian agamid genera. Sequences from three protein-coding genes (ND1, ND2, and COI) and eight intervening tRNA genes are examined using both parsimony and maximum-likelihood analyses. Species of Ctenophorus form a monophyletic group with Rankinia adelaidensis, which we suggest placing in Ctenophorus. Ecological differentiation among species of Ctenophorus is most evident in the kinds of habitats used for shelter. Phylogenetic analyses suggest that the ancestral condition is to use burrows for shelter, and that habits of sheltering in rocks and shrubs/hummock grasses represent separately derived conditions. Ctenophorus appears to have undergone extensive cladogenesis approximately 10-12 million years ago, with all three major ecological modes being established at that time.

Adaptation, Physiological↗
PubMed2001

Testing surgical skills of obstetric and gynecologic residents in a bench laboratory setting: validity and reliability.

OBJECTIVE: Resident surgical skills are acquired mainly through observing and later performing procedures in the operating room. Evaluation of surgical skills has traditionally been done through subjective faculty evaluation, a technique that has poor reliability and unknown validity. Our goal was to develop specific surgical tasks, both laparoscopic and open abdominal, that could be objectively and reliably evaluated in a bench laboratory setting. STUDY DESIGN: The prospective development of a reliable and valid resident surgical skills test in a bench laboratory setting was our goal. A written test of surgical knowledge and 12 skills tests were administered to 36 residents. Laparoscopic bench tasks were simulated with the use of a box and camera with a video display. Six laparoscopic tasks were assessed, including placing pegs on a board, running the bowel simulation, and other tasks that involve hand-eye coordination and manual dexterity. Open abdominal skills simulated incision closure, suturing a vaginal cuff, knot tying, and using a tie on a passer. Residents were timed at each given station and were given a rating score by 2 examiners. RESULTS: Knowledge scores showed a significant improvement by residency level. Assessment of construct validity (the ability to discriminate among residency levels) demonstrated significant differences on the rating of overall performance and individual tasks by level (determined by 1-way analysis of variance). Interrater reliability (agreement between 2 raters) with the use of intraclass correlation was 0.79 for the total score. The cost to administer the bench laboratory test was less than $50 and required 30 hours of faculty time. CONCLUSION: The results of this study suggest that surgical bench laboratory tasks can assess residents' surgical skills with good reliability and validity on most tasks. Our previous study, which used an animal laboratory, was expensive, and the bench laboratory model may provide an alternative means to assess surgical skills.

Clinical Competence↗
PubMed1999

238Pu alpha-particle-induced C3H10T1/2 transformants are less tumorigenic than the X-ray-induced equivalent.

Transformation is a complex multistage process in vitro by which benign cells gradually acquire characteristics of tumour cells. Transformed C3H10T1/2 cells appear in vitro as multilayers of cells termed foci. A variety of transformed phenotypes are observed in vitro and in this study samples of these phenotypes were developed as cell lines and assessed for their ability to induce tumours in C3H mice. It was found that, while a high proportion of X-ray-induced transformants were tumorigenic, most of the alpha-particle-induced transformants were non-tumorigenic. Although tumours produced by the X-ray-induced transformants appeared earlier, they grew at similar rates to the alpha-particle-induced equivalent. Foci were classified as fully or partially tumorigenic depending on whether the foci produced at least one tumour in the mice injected (partially tumorigenic) or produced tumours in all mice injected (fully tumorigenic). It was found that tumours from the partially tumorigenic foci grew slower or appeared later than those of the fully tumorigenic foci. It is hypothesized that the apparent low tumorigenicity of positively transformed alpha-particle-induced foci is due to an increase in genomic instability of progeny focus cells compared with X-ray-induced foci leading to a larger non-viable population of cells in the alpha-particle-induced foci.

Alpha Particles↗
PubMed1998

Lisinopril, an angiotensin I-converting enzyme inhibitor, prevents entry of murine hematopoietic stem cells into the cell cycle after irradiation in vivo.

The hemoregulatory peptide N-Acetyl-Ser-Asp-Lys-Pro (AcSDKP) has been shown in vivo to inhibit the cycling of murine hematopoietic stem cells triggered into S-phase by either cytotoxic drug administration or irradiation. This property, further confirmed using in vitro models, demonstrates that the peptide has an in vivo protective effect on the hematopoietic system. AcSDKP has been shown to be a physiological substrate of angiotensin I-converting enzyme (ACE), which catabolizes the peptide through a dipeptidasic activity. Thus, oral administration of ACE inhibitor to humans has led to an increase in the plasma AcSDKP concentration. In the present paper, we report on the in vivo effect of lisinopril, an ACE inhibitor, on the proliferative status of murine hematopoietic stem cells triggered into S-phase by irradiation. Administration of lisinopril (10 mg/kg) 1 hour after irradiation led to a 90 to 100% inhibition of murine plasma ACE activity as observed during the first 4 hours postirradiation. This inhibition was correlated with a 600% increase in the endogenous plasma AcSDKP level and a total suppression at 24 hours of entry of the hematopoietic stem cell into the cell cycle. We discuss the possible role of ACE in the regulation of hematopoietic stem cell proliferation through control of the AcSDKP concentration.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1992

The mechanism of action of the tetrapeptide acetyl-N-Ser-Asp-Lys-Pro (AcSDKP) in the control of haematopoietic stem cell proliferation.

The mechanism of action of the haemoregulatory tetrapeptide Acetyl-N-Ser-Asp-Lys-Pro (AcSDKP, M(r) = 487 amu), was investigated using an in vitro assay of a murine high proliferative potential colony-forming cell (HPP-CFC) which responds to proliferation regulators of the haematopoietic stem cell population. AcSDKP had no direct inhibitory effect on the number, or the proportion in S phase, of the committed granulocyte-macrophage progenitor (GM-CFC), or cycling HPP-CFC populations. However, AcSDKP blocked the action of a stimulator of haematopoietic stem cell proliferation, preventing the switching of quiescent HPP-CFC into cell cycle. It would appear that AcSDKP exerts its inhibitory haemoregulatory role indirectly, by preventing stimulator action on haematopoietic stem cells.

Amino Acid Sequence↗
PubMed1992

A 10-year follow-up survey of acceptability of controlled drinking in Britain.

This study was designed to reassess the acceptability of controlled drinking (CD) approximately 10 years after Robertson and Heather's (1982) survey of British treatment providers. Sixty percent of a wide range of almost 300 targeted alcohol service agencies in Scotland, England and Wales responded to a mailed questionnaire. Three-quarters of these respondents reported that nonabstinence was an acceptable outcome goal. About half of the respondents who accept CD reported it as acceptable for only 1-25% of their clientele. Within the subgroup of outpatient agencies, almost one-third reported CD as appropriate for at least 50% of their clientele. Respondents endorsing CD rated severity of dependence, client attitudes and beliefs about controlled drinking and abstinence, drinking history, liver function test results and social stability/social relationships as the most important factors of those listed in selecting outcome goals. Respondents reportedly based acceptance or rejection of CD most frequently on their own professional experience and, to a lesser extent, on research evidence for or against CD and on agency policy.

Adult↗
PubMed1991

A guide to the selection of paediatric tracheostomy tubes.

A large range of tracheostomy tube types and sizes are available for use in children. Regional preference, rather than individual patient assessment, tends to determine selection. We present a table designed to assist with appropriate size selection, and discuss the relative merits and shortcomings of the tubes currently available.

Adolescent↗
PubMed1991

Persistence of murine myeloid leukaemic cells in long-term bone marrow cultures.

Patterns of growth in long-term bone marrow culture were compared for a number of murine myeloid leukaemias. A leukaemic pattern of haematopoiesis was maintained in culture for a period of at least 15 weeks for one of the lines. However in the other five murine myeloid leukaemic lines studies, the leukaemic cells appeared not to survive in culture and normal haematopoiesis was established. Transplantation of cells from these established cultures at weeks 7 or 11 into syngeneic recipients revealed that leukaemic cells were present. Thus leukaemic cells seem to persist in long-term bone marrow cultures even in morphologically normal cultures.

Animals↗
PubMed1989

Cyclizine abuse among a group of opiate dependents receiving methadone.

Twenty opiate dependents receiving long-term prescriptions of oral methadone, were identified as being habitual abusers of the anti-emetic drug cyclizine. A semi-structured interview elicited the dosage of cyclizine used, its effects, the reasons for starting and persisting with abuse of cyclizine and the attitudes of the patients to it. Cyclizine was taken in large doses intravenously with methadone. The effects initially were of intense stimulation, often with hallucinations, sometimes with aggressive behaviour, and occasionally with epileptic fits. Subsequent depressive mood changes occurred often accompanied by a craving for cyclizine. Tolerance to the drug occurred but no clear cut withdrawal syndrome is apparent. It seems that dependence upon cyclizine occurs. The significance of these findings for doctors, pharmacists and for drug treatment units is discussed. The paucity of information on the pharmacology and pharmacokinetics is noted.

Adult↗
PubMed1975

Longitudinal contractions in the duodenum: their fluid-mechanical function.

The hypothesis examined was that contractions of the longitudinal muscle layer occurin the duodenum which are independent of those of the circular muscle layer and that they induce flow of duodenal contents. A segment of opossum duodenum isolated in vitro was marked and photographed during periods of longitudinal muscle contraction, when the circular muscle layer appeared inactive. The prequency of longitudinal oscillation of the marked points was 20.5 cycles/min. The longitudinal displacement wave spread caudad with an average velocity of 3.27 cm/s. Frequency and velocity of electrical slow waves were determined in similiar duodenal segments. Slow-wave frquencywas 18.9 cycles/min. In a two-dimensional mechanical model, flow induced by simulatedlongitudinal muscle layer appear to be driven by the electrical slow waves of the duodenum. They are capable of inducing a pattern of flow in which ocntents flow betweenthe core and the periphery of the intestinal conduit.

Animals↗