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Biomedical subjects

M Turner

Publications and source records attributed to M Turner.

At least 109 records · Page 6Linked to original sources
PubMed1999

Prospective study of high dependency care requirements and provision.

BACKGROUND AND PURPOSE OF THE STUDY: To compare the level of post-operative care requested for surgical patients with that provided in a Scottish teaching hospital. METHODS: A three months pragmatic prospective observational study was undertaken which included patients undergoing major surgery excluding gynaecological and elective orthopaedic surgery. A study specific questionnaire was used to collate the information. The data were inputted to DataEase 4.5 and subsequently exported to SPSSWIN version 6.1.3 for analysis. The main outcome measure was the level of care requested and the level of care actually received. MAIN FINDINGS: Among 1363 patients a total of 1395 operations were performed. The median age was 59 years with a male: female ratio of 1.1:1. The type of admission was elective in 58% and emergency in 42% of cases. The operations were elective in 44% and nonelective in 56% of cases. The ASA score was 3 or greater in 33% of patients. The optimum level of care requested by surgeons and anaesthetists was intensive therapy unit (ITU) in 9.7% and high dependency unit (HDU) in 23.6% of patients. Twenty-one (15.9%) of 132 ITU requests and 256 (73.8%) of 349 HDU requests were not met immediately post-operatively. Overall mortality was 1.5%. For those patients who received optimum requested care mortality was 1.2% and, in those patients who did not receive optimum requested care, mortality was 3.1% (p < 0.038: Chi-square). CONCLUSION: This study confirms a significant lack of access to properly staffed and equipped HDU facilities in a major teaching hospital with a consequent increase in mortality in those not receiving optimal post-operative care.

Adolescent↗
PubMed1999

The Ha locus of wheat: identification of a polymorphic region for tracing grain hardness in crosses.

The grain softness proteins or friabilins are known to be composed of three main components: puroindoline a, puroindoline b, and GSP-1. cDNAs for GSP-1 have previously been mapped to group-5 chromosomes and their location on chromosome 5D is closely linked to the grain hardness (Ha) locus of hexaploid wheat. A genomic DNA clone containing the GSP-1 gene (wGSP1-A1) from hexaploid wheat has been identified by fluorescent in situ hybridization as having originated from the distal end of the short arm of chromosome 5A. A genomic clone containing the gene (wGSP1-D1) was also isolated from Aegilops tauschii, the donor of the D genome to bread wheat. There are no introns in the GSP-1 genes, and there is high sequence identity between wGSP1-A1 and wGSP1-D1 up to 1 kb 5' and 300 bp 3' to wGSP1-D1. However, regions further upstream and downstream of wGSP1-D1 share no significant sequence identity to corresponding sequences in wGSP1-A1. These regions therefore identified potentially valuable sequences for tracing the Ha locus through assaying polymorphic DNA sequences. The sequence from 300 to 500 bp 3' to wGSP1-D1 (wGSP1-D13) was mapped to the Ha locus in a mapping population. wGSP1-D13 was also tightly linked to genes for puroindoline a and puroindoline b which have been previously mapped to be at the Ha locus. In addition wGSP1-D13 was used to detect RFLPs between near isogenic soft and hard Falcon lines and in a random selection of soft and hard wheats.

Base Sequence↗
PubMed1999

Microtechnologies: art or engineering?

Recent developments in micromachining are showing that much more can be achieved at acceptable costs than may have previously been thought possible. One of the biggest challenges, says the author, is unleashing the engineers' imagination. This article tackles some of the problems found in making and using machined microcomponents and offers some solutions.

Biomedical Engineering↗
PubMed1999

Adhesives: a selection guide.

This article analyses the use of three types of adhesive for medical device assembly. The advantages and disadvantages, typical applications and key features are defined for cyanoacrylate, epoxies and UV- and light-cured adhesives.

Adhesiveness↗
PubMed1998

Fc epsilon receptor I-associated lyn-dependent phosphorylation of Fc gamma receptor IIB during negative regulation of mast cell activation.

Fc gamma RIIB are low-affinity receptors for IgG whose intracytoplasmic domain contains an immunoreceptor tyrosine-based inhibition motif (ITIM). Fc gamma RIIB inhibit cell activation triggered by receptors that signal via immunoreceptor tyrosine-based activation motifs. This inhibition requires ITIM tyrosyl phosphorylation and is correlated with the binding of SH2 domain-containing phosphatases that may mediate the inhibitory signal. In the present work, we investigated the mechanism of Fc gamma RIIB phosphorylation and its consequences in mast cells. We demonstrate that the phosphorylation of Fc gamma RIIB requires coaggregation with Fc epsilon RI and that, once phosphorylated, Fc gamma RIIB selectively recruit the inositol polyphosphate 5 phosphatase SHIP, in vivo. In vitro, however, the phosphorylated Fc gamma RIIB ITIM binds not only SHIP, but also the two protein tyrosine phosphatases, SHP-1 and SHP-2. We show that the coaggregation of Fc gamma RIIB with Fc epsilon RI does not prevent Fc epsilon RI-mediated activation of lyn and syk. Both kinases can phosphorylate Fc gamma RIIB in vitro. However, when coaggregated with Fc epsilon RI, Fc gamma RIIB was in vivo phosphorylated in syk-deficient mast cells, but not in lyn-deficient mast cells. When Fc epsilon RI are coaggregated with Fc gamma RIIB by immune complexes, Fc epsilon RI-associated lyn may thus phosphorylate Fc gamma RIIB. By this mechanism, Fc epsilon RI initiate ITIM-dependent inhibition of intracellular propagation of their own signals.

Animals↗
PubMed1998

Epoxybutene-hemoglobin adducts in rats and mice: dose response for formation and persistence during and following long-term low-level exposure to butadiene.

Measurement of specific adducts to hemoglobin can be used to establish the dosimetry of electrophilic compounds and metabolites in experimental animals and in humans. The purpose of this study was to investigate the dose response for adduct formation and persistence in rats and mice during long-term low-level exposure to butadiene by inhalation. Adducts of 3,4-epoxy-1-butene, the primary metabolite of butadiene, with N-terminal valine in hemoglobin were determined in male B6C3F1 mice and male Sprague-Dawley rats following exposure to 0, 2, 10, or 100 ppm of 1,3-butadiene, 6 h/day, 5 days/week for 1, 2, 3, or 4 weeks. Blood samples were collected from groups of five mice and three rats at the end of each week during the 4 weeks of exposure and weekly for 3 weeks following the end of the 4-week exposure period. The increase and decrease, respectively, of the adduct levels during and following the end of the 4-week exposure followed closely the theoretical curve for adduct accumulation and removal for rats and mice, thereby demonstrating that the adducts are chemically stable in vivo and that the elimination follows the turnover of the red blood cells. The adduct level increased linearly with butadiene exposure concentration in the mice, whereas a deviation from linearity was observed in the rats. For example, after exposure to 100 ppm butadiene, the epoxybutene-hemoglobin adduct levels were about four times higher in mice than in rats; at lower concentrations of butadiene, the species difference was less pronounced. Blood concentrations of epoxybutene, estimated from hemoglobin adduct levels, were in general agreement with reported concentrations in mice and rats exposed by inhalation to 62.5 ppm. These studies show that adducts of epoxybutene with N-terminal valine in hemoglobin can be used to predict blood concentration of epoxybutene in experimental animals.

Algorithms↗
PubMed1998

Can the number of cigarettes smoked predict high-grade cervical intraepithelial neoplasia among women with mildly abnormal cervical smears?

OBJECTIVE: We investigated whether the number of cigarettes smoked by women who had mildly abnormal cytologic study results could identify those at risk for high-grade dysplasia. STUDY DESIGN: This was a prospective study of all women who were referred for colposcopy with a mildly abnormal cervical smear over a 4-year period. A detailed questionnaire was completed that evaluated sociodemographic characteristics including smoking history. Colposcopy then determined the degree of disease. RESULTS: One hundred seventy-three women were referred with a mildly abnormal cervical smear. There was a significant relationship between the numbers of cigarettes smoked and the risk of high grade disease (P = .007). Once the number of cigarettes smoked daily exceeded 20, the risk of high grade cervical intraepithelial neoplasia was increased fivefold (odds ratio 5.85 [95% confidence interval 1.92 to 17.80]). CONCLUSION: Cigarette smoking is associated with a dose-dependent increased risk of cervical intraepithelial neoplasia grade 2 or 3 among women who have mildly abnormal cervical smears.

Adult↗
PubMed1998

Adjudicating ventilator-associated pneumonia in a randomized trial of critically ill patients.

PURPOSE: The purpose of this study was to evaluate an adjudication strategy for diagnosing ventilator-associated pneumonia (VAP) in a randomized trial. MATERIALS AND METHODS: In a double-blind trial of sucralfate versus ranitidine, one of four pairs of adjudicators examined each case of clinically suspected VAP. Nurse and physician notes and all relevant laboratory data were allocated to each adjudication pair in groups of five patients. Each reader in the pair decided whether the patient had VAP; differences were resolved by consensus discussion. RESULTS: The overall unadjusted study odds ratio for VAP was 0.82 (P = .21) representing a trend toward less pneumonia with sucralfate compared with ranitidine. The odds ratio adjusted for adjudication pair was 0.85 (P = .27). The proportion of charts adjudicated as VAP positive among pairs ranged from 50% to 92%; crude agreement between readers in each pair varied from 50% to 82%. When adjudicators disagreed, the final consensus was split evenly between the two adjudicators' initial opinions in two pairs; in the other two pairs, the final decision reflected one dominant initial opinion. Personnel time to adjudicate all patients with a suspicion of VAP was 74 days. CONCLUSIONS: Though adjudication of outcomes such as VAP is time-consuming, consistent decision-making requires strict criteria, training, and calibration. Patients should be assigned to adjudication teams through random allocation.

Anti-Ulcer Agents↗
PubMed1998

CD19 as a membrane-anchored adaptor protein of B lymphocytes: costimulation of lipid and protein kinases by recruitment of Vav.

CD19 is a coreceptor that amplifies signaling by membrane immunoglobulin (mIg) to promote responses of the B lymphocyte to T-dependent antigens. Vav is a guanine nucleotide exchange factor for the Rho, Rac, Cdc42 family of small GTPases. We found that coligating mIg and CD19 causes a synergistic increase in the tyrosine phosphorylation of CD19. Phosphorylated tyrosine-391 of CD19 binds Vav to mediate a sustained increase in intracellular Ca2+ concentration. This response correlates with activation by the CD19-Vav complex of phosphatidylinositol 4-phosphate 5-kinase for the synthesis of phosphatidylinositol 4,5-bisphosphate. Interaction of CD19 with Vav also mediates the synergistic activation of the mitogen-activated protein kinase JNK. Therefore, CD19 is a membrane adaptor protein that recruits Vav for the activation of lipid and protein kinases.

Animals↗
PubMed1998

Observation of a paradoxical temperature increase during cognitive stress in some chronic pain patients.

A total of 224 chronic pain somatoform disorder patients without obvious pathophysiology or psychopathology were found to have colder hands than nonpatients. A paradoxical temperature increase (PTI) in response to a cognitive stressor (mental arithmetic) was noted in a subset of these chronic pain patients. Patients were defined as "PTI" responders if, during cognitive stress, an increase in digital temperature occurred over a prior eyes closed resting condition. It was found that 49.4% of males and 42.6% of females in a total sample of 224 patients demonstrated PTI. The PTI patients had significantly colder hands than non-PTI patients prior to stress. A concurrent SCL measure of sympathetic activation found no difference between the PTI and non-PTI groups either at baseline or during cognitive stress. It appears from this data that PTI is specific to the peripheral vascular system of these patients and may be a marker of psychophysiological dissociation or trauma blocked from consciousness.

Adult↗
PubMed1998

Reversion to back-up mode (VOO) in a DDD pacemaker model.

Sorin recently identified mode reversion to backup mode (VOO). They estimate a prevalence of 1% and suggest electromagnetic interference (EMI) as the cause. We identified ten patients being followed in our pacing clinic, of whom four were found to have suffered mode reversion. We, therefore, conclude that the prevalence of this problem may be greater than predicted. None of the patients who were found to have mode reversion gave any history to suggest that they had been exposed to EMI.

Arrhythmias, Cardiac↗