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Biomedical subjects

L Ross

Publications and source records attributed to L Ross.

At least 37 records · Page 2Linked to original sources
PubMed2000

Illicit drug use related attendances at accident and emergency services in Aberdeen: a prospective six month survey.

OBJECTIVE: To quantify and examine the nature of known illicit drug related attendances at the Accident and Emergency Department of Aberdeen Royal Hospital over a six month period. DESIGN: A structured questionnaire was completed by Accident and Emergency staff. SETTING: The Accident and Emergency Department of Aberdeen Royal Hospital. SUBJECTS: All patients presenting at the Accident and Emergency Department as a result of known illicit drug use between November 1996 to April 1997 inclusive. RESULTS: One hundred and fifty seven subjects presented at Accident and Emergency during the six month period. Peak attendance was between 18.00 and 21.00 hours. Twenty seven percent of patients chose to visit Accident and Emergency rather than their own general practitioner. Thirty seven percent had no involvement with any health care professional regarding their drug use. Heroin was used by 62% of cases of which the majority (94.9%) had injected and stimulants such as amphetamine and ecstasy were used by a large proportion of cases. Only 4.5% of subjects admitted to not using clean equipment yet 15% admitted to have loaned equipment (to someone else) and 22% of subjects had injecting related problems. Thirteen percent of subjects were considered unco-operative by staff. Fifty four percent of subjects required admission to a ward and ten patients (6%) died. CONCLUSION: Heroin continues to be the main drug causing major health problems. Harm reduction messages are not adequately reaching/or being taken up by drug users given the high proportion with injecting related problems and those being prepared to lend needles. The receptive attitude amongst subjects highlighted the opportunity for patient education as well as giving contact addresses of relevant organisations.

Emergency Service, Hospital↗
PubMed1999

Rapid detection of the HIV type 1 reverse transcriptase codon T215Y by reverse transcription-polymerase chain reaction with fluorogenic probes.

Early detection of viral mutations, particularly those mutations associated with cross-resistance to antiretroviral drugs, is critical both for understanding the mechanism of drug resistance and for the clinical management of patients infected with HIV-1. One of the frequently observed mutations in the HIV-1 reverse transcriptase (RT)-coding region is ACC --> TAC at codon 215, resulting in a change of wild-type threonine (T) to tyrosine (Y); this mutation has been associated with decreased phenotypic susceptibility to zidovudine (ZDV). We describe a technique for the detection of the T215Y mutation using reverse transcription-polymerase chain reaction (RT-PCR) amplification of viral sequences and a 5' nuclease assay requiring fluorogenic probes. In addition to detecting the presence of the ACC --> TAC mutation at codon 215, this assay provides an increased ability to detect low levels of mutant species in a mixed population, relative to conventional sequencing. Further advantages of this technique include the rapid and high-throughput nature of the assay, the accuracy of the assay relative to conventional DNA sequencing, and the convenience of combining RT-PCR virus amplification with the allelic discrimination assay, without the need for purification of PCR products.

Anti-HIV Agents↗
PubMed1999

Changes in attractiveness of elected, rejected, and precluded alternatives: a comparison of happy and unhappy individuals.

In 3 studies the authors compared the responses of self-rated happy and unhappy students in situations involving choice. In Study 1, high school seniors evaluated colleges after applying for admission and then later after making their selections. Happy students tended to be more satisfied than unhappy ones with the colleges they ultimately chose and those they ultimately rejected, and they more sharply devalued the colleges that rejected them. Studies 2 and 3 dealt with postdecisional consequences of less consequential decisions about fancy desserts. In Study 2, unhappy participants sharply derogated the desserts they rejected or were denied, relative to those selected by or for them, whereas happy participants showed no such derogation. These group differences, moreover, proved to be largely independent of self-esteem and optimism. The design of Study 3 helped explicate underlying mechanisms by inducing both groups to distract themselves or to self-reflect. Doing so eliminated all group differences. Implications of the results for the link between cognitive processes and hedonic consequences are discussed.

Analysis of Variance↗
PubMed1999

Progress's Pilgrim: a critical narrative of research in progress.

There is increasing interest in the use of stories to develop nursing and health care practice. This paper reports on how we used story to understand and develop research on nursing practice. Story (or narrative) and science can be seen as distinct but complementary paradigms. We have found that a story framework can help researchers to reflect on a process of social scientific investigation, and to consider how to 'go on' in that process. In a study on 'Community psychiatric nurses' empowerment of people with enduring mental disorders in the community: involving users to develop services' we have encountered a number of interesting and challenging issues related to design and use of methods. We present these issues within a framework of story analysis, focusing on issues related to empowerment. This analysis draws on Burke's 'pentad' of story elements as a framework for narrative analysis. We present the elements of the 'story of the study-as-funded' and as it was carried out through the pilot stage, and outline the story of developments in the main study. 'Trouble' in a story centres on a problematic 'ratio' of story elements. The 'trouble' at this stage in the progress of our study relates to lack of fit between some parts of the instruments (the methods) and the goal (empowerment), and to the status of the CPNs as actors or agents. Narrative analysis sensitizes us to these issues of 'trouble' and provides a means of addressing them. Like John Bunyan's Pilgrim, we have learned through our progress; unlike Pilgrim, we know not our end.

Community Mental Health Services↗
PubMed1999

Quality of cryopreserved testicular sperm in patients with obstructive and nonobstructive azoospermia.

PURPOSE: Sperm retrieved by testicular sperm extraction is routinely used to attempt pregnancy by in vitro fertilization-intracytoplasmic sperm injection. We evaluated the efficacy of cryopreserving testicular sperm collected by testicular sperm extraction at diagnostic biopsy. MATERIALS AND METHODS: A total of 73 men with obstructive and 42 with nonobstructive azoospermia underwent testicular sperm extraction at diagnostic biopsy. Sperm was retrieved and cryopreserved in all cases of obstruction and in 15 of nonobstructive azoospermia cases. Before freezing we determined sperm count, motility, morphology and viability, and after thawing we assessed sperm motility and viability. In 17 couples a total of 20 cycles of in vitro fertilization-intracytoplasmic sperm injection were performed and fertilization, cleavage and pregnancy rates were determined in cases of obstruction and nonobstruction. RESULTS: Sperm count and morphology were lower in the testicular biopsies of men with nonobstructive versus obstructive azoospermia. Motility was low or absent in all testicular sperm extraction specimens. Importantly, pre-freeze (63%) and post-thaw (31%) viability was the same in both patient groups. After in vitro fertilization-intracytoplasmic sperm injection using frozen and thawed testicular sperm the fertilization, cleavage, implantation and clinical pregnancy rates were 60, 86, 16 and 50%, respectively. Using cryopreserved sperm we observed no differences in outcome of any in vitro fertilization-intracytoplasmic sperm injection procedure in patients with obstructive versus nonobstructive azoospermia. CONCLUSIONS: Cryopreservation of testicular sperm provides enough good quality sperm after thawing to result in excellent in vitro fertilization-intracytoplasmic sperm injection outcomes. Cryopreservation does not adversely affect intracytoplasmic sperm injection outcomes, including pregnancy rate. Therefore, we recommend routine testicular sperm extraction and cryopreservation of sperm at testicular biopsy.

Cryopreservation↗
PubMed1998

A novel isoform of the mitochondrial outer membrane protein VDAC3 via alternative splicing of a 3-base exon. Functional characteristics and subcellular localization.

Voltage-dependent anion channels (VDACs) are pore-forming proteins found in the outer mitochondrial membrane of all eucaryotes. VDACs are the major pathway for metabolites through the outer mitochondrial membrane and, in mammals, bind several cytosolic carbohydrate kinases. Whereas yeast contain a single VDAC (YVDAC), to date three isoforms have been described in the mouse that constitute a gene family. We have observed an additional isoform of VDAC3 that appears to be generated via the tissue-specific alternative splicing of a 3-base exon (ATG). The exon is predicted to introduce a methionine 39 amino acids downstream of the amino terminus of the polypeptide. Between exons 3 and 4 is an intronic sequence that potentially encodes the exon, with flanking splice enhancer elements. Expression of this alternative form in the mouse is limited to brain, heart, and skeletal muscle. Complementation of YVDAC-deficient yeast by the two isoforms and with other sequence variants of VDAC3 suggests this residue is an important modulator of VDAC3 function. In transfected mammalian cells both isoforms localize to mitochondria. A similar variant is present in humans.

3T3 Cells↗
PubMed1998

Evidence that IgE receptor stimulation increases adenosine release from rat basophilic leukaemia (RBL-2H3) cells.

Adenosine may play a role in asthma by enhancing inflammatory mediator release from lung mast cells. In this study, we investigated whether adenosine is released from cultured rat basophilic leukaemia (RBL-2H3) cells in response to antigen challenge and whether released adenosine enhances mediator release. RBL-2H3 cells closely resemble mucosal mast cells, the most common type of mast cell in lung tissue, and they express adenosine A3 receptors (which have been associated with asthma). Measurement of adenosine in RBL-2H3 cell incubation medium was possible if adenosine metabolism was inhibited by EHNA (10 microM; an adenosine deaminase inhibitor) and 5-iodotubericidin (5-IT; 10 microM; an adenosine kinase inhibitor). Basal adenosine concentration increased up to 1.0 microM during a 90 min incubation; after antigen challenge, adenosine concentration was increased by 0.3-0.4 microM above basal. Antigen-induced adenosine release ranged from 30-70 nmol/1.25x10(6) cells. Antigen-induced mediator release (beta-hexosaminidase and [3H]5-hydroxytryptamine) was increased by APNEA, an adenosine A3 receptor agonist (EC50 approximately 20 nm) but inhibited by EHNA and 5-IT, despite increased adenosine levels. This inhibition was not blocked by the adenosine A1/A2 receptor antagonist DPSPX (5 microM). Therefore, it is unlikely to be related to adenosine receptor activation. In conclusion, although our data provide no direct support for a positive feedback effect of adenosine on mast cell mediator release, the observation that IgE receptor stimulation increases adenosine production in cells which express stimulatory A3 receptors is consistent with this hypothesis.

Adenine↗
PubMed1998

A comparison of social phobia outcome measures in cognitive-behavioral group therapy.

This article reports the effects of a cognitive-behavioral group therapy program for social phobia (N = 25 outpatients) on several psychometric measures. It is the first study to simultaneously examine three newer and promising social-phobia measures: the Social Phobia Scale (SPS) and accompanying Social Interaction Anxiety Scale (SIAS), the Social Phobia and Anxiety Inventory (SPAI), and the Liebowitz Social Anxiety Scale (LSAS). More traditional measures of social phobia were also included, along with measures of anxious and depressed mood. Among the newer scales, the SPAI and SPS/SIAS were found to have good sensitivity to treatment. There was limited support for the LSAS. Intercorrelations among all of the outcome measures are presented both before and after cognitive-behavioral therapy. Strengths and weakness of each of the newer social-phobia measures are discussed.

Adult↗
PubMed1997

Cycloheximide inhibition of delayed early gene expression in baculovirus-infected cells.

The baculovirus protein IE1 is required for the transactivation of many early viral genes in transient expression assays. However, cycloheximide inhibition studies have failed to reveal a dependence of early gene transcription on expression of IE1 in infected cells. We show here that synthesis of IE1 was not effectively inhibited by the addition of 100 microg/ml cycloheximide, the concentration routinely used in these studies. However, when cycloheximide was added at 250 microg/ml, IE1 synthesis was repressed to less than 5% of control levels. These more stringent conditions were used to discriminate between immediate early and delayed early genes. Transcription of three immediate early genes (ie1, ie2, and ie0) was increased by the addition of high concentrations of cycloheximide. However, transcription of three other early genes (39k, p35, and lef-3), which are known to be dependent on IE1 transactivation, was significantly reduced by the addition of 250 microg/ml cycloheximide. Immunoblot analyses also revealed a difference between the immediate and delayed early class of viral genes. Synthesis of IE1, IE2, and IE0 was resistant to cycloheximide treatment, while translation of SSB/LEF-3 and pp31 was strongly inhibited even at the lower concentration of cycloheximide. Although cycloheximide was shown to be useful in defining early temporal classes, it induced apoptosis in both uninfected and infected Sf9 cells when used at the inhibitory concentration.

Animals↗
PubMed1997

Motivation underlying career choice for internal medicine and surgery.

Self-determination theory (Deci and Ryan, 1985) was used to predict medical students' career choices for internal medicine or surgery based on their experiences of the autonomy support provided by the instructors in the two corresponding third-year clerkships. Fourth-year medical students (n = 210) at three medical schools completed questionnaires that assessed (1) retrospective prior likelihood (as of the end of second year) of their going into internal medicine and surgery, (2) their perceived competence with respect to these two medical specialties, (3) their interest in the problems treated in each specialty, (4) the autonomy support of the instructors on the two corresponding rotations, (5) the current likelihood (late in the fourth year) of going into each of the two specialties, and (6) their actual residency choices. For a subset (n = 64), actual prior likelihoods of going into the two careers had also been assessed at the end of their second year. Structural equation modeling confirmed, as hypothesized, (a) that perceived autonomy support of the corresponding clerkship would predict students' choices of internal medicine or surgery, even after the effects of retrospective (and actual) prior likelihood had been removed, and (b) that this relationship between perceived autonomy support and career choice was mediated by perceived competence and interest. The present study suggests that students' experiences on clerkships do affect the likelihood that they will select particular specialties, and that students' interest in the areas are good indicators of the selections they will make.

Adult↗
PubMed1997

Self-interest and fairness in problems of resource allocation: allocators versus recipients.

Two studies explored the tension between self-interest and the equality norm in problems of resource allocation. Study 1 presented graduate business students with a hypothetical task requiring them to make a series of managerial decisions. On learning the outcome of those decisions, they were asked to divide a bonus pool between self and a rival manager (who had opted for very different decisions and achieved either the same results as self on 2 criteria or a better result on 1 criterion and a worse result on the other criterion). Study 2 required Stanford and San Jose State undergraduates to consider the division of a hypothetical scholarship fund between candidates from their 2 schools. Data from both studies contrasted the apparent evenhandedness and lack of self-interest manifested by allocators with the self-serving responses of evaluators. Furthermore, when faced with different claims, participants were inclined to justify an unequal allocation of resources--provided that they, or a representative of their group, received the larger share--that few personally would have recommended, demanded, or imposed.

Defense Mechanisms↗
PubMed1997

Hedonic consequences of social comparison: a contrast of happy and unhappy people.

Two studies tested the hypothesis that self-rated unhappy individuals would be more sensitive to social comparison information than would happy ones. Study 1 showed that whereas unhappy students' affect and self-assessments were heavily affected by a peer who solved anagrams either faster or slower, happy students' responses were affected by the presence of a slower peer only. These between-group differences proved to be largely independent of 2 factors associated with happiness, i.e., self-esteem and optimism. Study 2 showed that whereas the unhappy group's responses to feedback about their own teaching performance were heavily influenced by a peer who performed even better or even worse, happy students' responses again were moderated only by information about inferior peer performance. Implications for our appreciation of the link between cognitive processes and "hedonic" consequences are discussed.

Achievement↗
PubMed1997

Morphologic and molecular changes induced by recombinant human leptin in the white and brown adipose tissues of C57BL/6 mice.

Leptin is a 16-kd protein synthesized and secreted by adipose tissue, which regulates adiposity and body weight. To investigate the peripheral effects of recombinant human leptin, lean C57BL/6 mice were treated with subcutaneous injections of vehicle or 20 mg/kg/day leptin for 1 to 14 days. Groups of animals were killed on Days 1, 2, 3, 4, 7, or 8 and 15 to evaluate the time course of clinical chemistry, morphologic, and molecular changes in white (WAT) and brown adipose tissue (BAT) depots. There was a progressive daily reduction in the body weight of mice receiving leptin. By Day 15, the body weight of leptin-treated groups decreased by 6% to 8% relative to base-line weight. Clinical chemistry changes in treated mice included decreased cholesterol and triglyceride levels. At necropsy, the mice had rapidly progressive atrophy of subcutaneous, intra-abdominal, and retroperitoneal WAT and interscapular BAT depots, with complete depletion of fat stores by Days 3 to 4 in most females and by Days 7 to 14 in male mice. Histologically, white and brown adipocytes underwent marked atrophy with loss of lipid droplets and activation of BAT cells in WAT depots. Ultrastructurally, white and brown adipocytes contained numerous, enlarged mitochondria. Molecular analysis of key adipose tissue genes in brown and white fat depots revealed a rapid, selective increase in the mRNA expression of thermogenic proteins and lipolytic enzymes, including uncoupling proteins 1 and 2, lipoprotein lipase, and hormone-sensitive lipase, with decreases in the lipogenic enzyme fatty acid synthase, endogenous leptin, and cytochrome c oxidase. These data suggest that the peripheral effects of leptin include increased thermogenesis and lipid oxidation in brown fat coupled with increased lipolysis and decreased fat synthesis in white and brown fat, which lead to a rapid reduction in the body weight and adiposity of mice.

Adipose Tissue↗
PubMed1996

Identification of pesticide poisoning in wildlife.

The Wildlife Incident Investigation Scheme investigates incidents of suspected poisoning of wildlife (also honey bees and companion animals) by pesticides in the United Kingdom. The approach to these investigations has evolved over the past 30 years. Field investigations, post-mortem examinations, toxicological data and experience of previous poisoning incidents assist in the selection and interpretation of appropriate chemical analyses. Several 'multi-residue' and several 'individual compound' analytical methods for pesticides in wildlife are currently in use; these are described.

Animals↗
PubMed1996

Meiotic recombination initiated by a double-strand break in rad50 delta yeast cells otherwise unable to initiate meiotic recombination.

Meiotic recombination in Saccharomyces cerevisiae is initiated by double- strand breaks (DSBs). We have developed a system to compare the properties of meiotic DSBs with those created by the site-specific HO endonuclease. HO endonuclease was expressed under the control of the meiotic-specific SPO13 promoter, creating a DSB at a single site on one of yeast's 16 chromosomes. In Rad+ strains the times of appearance of the HO-induced DSBs and of subsequent recombinants are coincident with those induced by normal meiotic DSBs. Physical monitoring of DNA showed that SPO13: : HO induced gene conversions both in Rad+ and in rad50 delta cells that cannot initiate normal meiotic DSBs. We find that the RAD50 gene is important, but not essential, for recombination even after a DSB has been created in a meiotic cell. In rad50 delta cells, some DSBs are not repaired until a broken chromosome has been packaged into a spore and is subsequently germinated. This suggests that a broken chromosome does not signal an arrest of progression through meiosis. The recombination defect in rad50 delta diploids is not, however, meiotic specific, as mitotic rad50 diploids, experiencing an HO-induced DSB, exhibit similar departures from wild-type recombination.

DNA, Fungal↗