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Biomedical subjects

B Thomas

Publications and source records attributed to B Thomas.

At least 127 records · Page 7Linked to original sources
PubMed1996

Population risk factors for hospitalization for stroke in Scotland.

BACKGROUND: There is considerable heterogeneity of cerebrovascular disease (CVD) incidence throughout Scotland. We sought to relate this geographical variation to differences in population risk factors. METHOD: A computer search of linked national hospital discharge data was performed. Individuals were selected if they had been coded with a diagnosis of CVD (ICD-9 430-438), 1984-1986. Age-sex specific rates were correlated to deprivation score and estimated population risk factors for the 22 local government districts of the Scottish Heart Health Study (1984-1986). RESULTS: Men were more commonly admitted in all districts except one, with an overall male:female ratio of 1.43 (P < 0.0001). Rates for men were significantly higher in populations with elevated mean diastolic blood pressure, greater mean alcohol consumption, and where fewer men ate fruit. The most significant associations of male CVD hospital admissions were with population density and deprivation. A similar pattern was found for women, where CVD was significantly associated with elevated diastolic blood pressure, more smokers and fewer non-smokers, and fewer eating fruit. Again rates were higher in densely populated, deprived districts. Multiple linear regression identified the proportion for men. Sex difference was explained by vitamin C intake. CONCLUSION: Geographical variation in CVD rates in Scotland is related to identifiable population risk factors for atherosclerosis and urban environment.

Adult↗
PubMed1996

[Tracheobronchial cylindroma. Success after left pneumonectomy and plastic repair of a large right tracheobronchial break with a musculo-pleural pedicle and bone graft around a temporary Dumont prosthesis].

A 54-year-old woman with a cylindroma of the lower trachea underwent exploration with dissection of the tracheobronchial junction. The main left bronchus was invaded and there was major tissue loss of membranous tracheo-bronchial substance. Histology showed both tracheal and bronchial involvement. Left pneumonectomy was performed and a Dumon prosthesis was installed on the right. The prosthesis was enveloped in a musculopleural plasty reinforced with a vone graft. Good air flow was established immediately allowing secondary reconstruction of a perfectly functional neobronchus. Outcome was quite favorable with a 3 year follow-up.

Bone Transplantation↗
PubMed1996

Rethinking acute inpatient care.

Significant opportunities now exist for the treatment and care of people with mental illness and a range of community facilities are often provided. However, the specific role of the psychiatric inpatient unit within a comprehensive mental health service continues to be a focus of debate. In England, the Department of Health's policy is that specialist psychiatric services should target their efforts toward severely mentally ill people to ensure that they receive the treatment, care and follow up that they need. The current use of beds by those with severe mental illness has recently been reviewed at the Bethlem Royal and Maudsley Hospitals by examining a sample of 1000 people admitted to six acute wards over a two year period. The results suggest that the majority of people are admitted to hospital appropriately. However, research on inpatient wards reveals that nurses are not coping effectively with the changing inpatient population. Patient care plans often reveal a lack of co-ordination and clinical focus. It is proposed that greater attention to the reasons for admission to hospital will highlight priorities for care, leading to more purposeful interventions and ultimately better use of resources.

Acute Disease↗
PubMed1995

Inorganic components of drinking water and microalbuminuria.

Relatively little is known of the chronic effects attributable to the ingestion of inorganic components such as uranium and silicon. Although ingestion of large amounts of U can cause acute renal damage through a chemical effect, studies on humans have typically considered inhalation the route of exposure. We investigated the association between drinking water concentration levels of U and Si, and microalbuminuria, a sensitive biological indicator of renal dysfunction. Linear regression analysis revealed a statistically significant association between U cumulative exposure index and albumin per mmol creatinine (P = 0.03). No such significant relationship appeared for Si, although a positive trend was witnessed. Since normal but increasing levels of microalbuminuria were observed at U concentration levels below the Canadian Maximum Allowable Concentration (MAC), it is suggested that further study be undertaken.

Adolescent↗
PubMed1995

Increased incidence of renal cell tumors in a cohort of cardboard workers exposed to trichloroethene.

A retrospective cohort study was carried out in a cardboard factory in Germany to investigate the association between exposure to trichloroethene (TRI) and renal cell cancer. The study group consisted of 169 men who had been exposed to TRI for at least 1 year between 1956 and 1975. The average observation period was 34 years. By the closing day of the study (December 31, 1992) 50 members of the cohort had died, 16 from malignant neoplasms. In 2 out of these 16 cases, kidney cancer was the cause of death, which leads to a standard mortality ratio of 3.28 compared with the local population. Five workers had been diagnosed with kidney cancer: four with renal cell cancers and one with a urothelial cancer of the renal pelvis. The standardized incidence ratio compared with the data of the Danish cancer registry was 7.97 (95% CI: 2.59-18.59). After the end of the observation period, two additional kidney tumors (one renal cell and one urothelial cancer) were diagnosed in the study group. The control group consisted of 190 unexposed workers in the same plant. By the closing day of the study 52 members of this cohort had died, 16 from malignant neoplasms, but none from kidney cancer. No case of kidney cancer was diagnosed in the control group. The direct comparison of the incidence on renal cell cancer shows a statistically significant increased risk in the cohort of exposed workers. Hence, in all types of analysis the incidence of kidney cancer is statistically elevated among workers exposed to TRI.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Measurements of spin-lattice relaxation times, T1, in Na2O-MgO-SiO2 glasses doped with MnO.

Silicate glasses without paramagnetic components show 29Si relaxation times, T1, in the order of minutes. Because of these T1 values, unacceptably long instrument times are needed to obtain satisfactory' signal-to-noise ratios. Therefore, all samples were doped with MnO when microstructures of electrode glasses were investigated. Small amounts of paramagnetic ions in the glass reduce the relaxation time but do not affect the electrode properties. In any case when the distribution of manganese ions is homogeneous, the relaxation rates are proportional to the MnO content. The spin-lattice relaxation times of the different Qn species are similar within error limits. The best spectra were obtained using 0.1 mol% MnO.

Electrodes↗
PubMed1995

Solid-state nuclear magnetic resonance investigations on chlorocyclophosphazenes.

The present study deals with solid-state nuclear magnetic resonance (NMR) investigations on hexachlorocyclotriphosphazene (N3P3Cl6) and T and K form of octachlorocyclotetraphosphazene (N4P4Cl8). Using 31P NMR we have recorded spectra of different magic-angle spinning (MAS) frequencies and static powder spectra. By means of the analysis of spinning sideband intensities the isotropic chemical shifts and the principal values of the chemical shift tensor could be determined. Because of the interactions between phosphorus and the neighbouring chlorine nuclei in the MAS spectra of N3P3Cl6 and N4P4Cl8 more lines were found to exist than was expected with regard to the isotropic chemical shift values according to the crystallographic phosphorus positions. To support this evidence solid-state spectra of the geminally disubstituted compound 2,2,4,4-tetrachloro-6,6-bisthiophenylcyclotriphosphazene [N3P3Cl4(SPh)2] were used. In addition, by means of the individual gauched localized orbitals (IGLO) method 31P NMR chemical shifts, principal values and the orientation of the principal axes of the shielding tensor were calculated for the chlorocyclophosphazenes.

Data Interpretation, Statistical↗
PubMed1995

Detection of multiple boron sites in glasses by 11B satellite transition nuclear magnetic resonance spectroscopy.

The magic-angle spinning sidebands of the satellite transition (ST, m = +/- 3/2 <==> +/- 1/2) for 11B nuclear magnetic resonance (11B ST spectroscopy) have been used to detect multiple boron sites in Na2O-B2O3-SiO2 glasses. The experimental details and data analysis are described, how multiple BO4 and BO3 units can be distinguished using standard magic-angle spinning. For a 16Na2O-30B2O3-53.9SiO2 glass (0.1 MnO) two BO4 units with chemical shifts of -2.5 and 0 ppm were found which differ considerably in their quadrupole interaction. Besides this we found three different BO3 units with approximate chemical shifts of 17, 15, and 19 ppm. The results are compared with earlier measurements.

Boron↗
PubMed1995

Imidazoleacetic acid, a gamma-aminobutyric acid receptor agonist, can be formed in rat brain by oxidation of histamine.

It is generally accepted that in mammalian brain histamine is metabolized solely by histamine methyltransferase (HMT), to form tele-methylhistamine, then oxidized to tele-methylimidazoleacetic acid. However, histamine's oxidative metabolite in the periphery, imidazoleacetic acid (IAA), is also present in brain and CSF, and its levels in brain increase after inhibition of HMT. To reinvestigate if brain has the capacity to oxidize histamine and form IAA, conscious rats were injected with [3H]histamine (10 ng), either into the lateral ventricles or cisterna magna, and decapitated 30 min later. In brains of saline-treated rats, most radioactivity recovered was due to tele-methylhistamine and tele-methylimidazoleacetic acid. However, significant amounts of tritiated IAA and its metabolites, IAA-ribotide and IAA-riboside, were consistently recovered. In rats pretreated with metoprine, an inhibitor of HMT, labeled IAA and its metabolites usually comprised the majority of histamine's tritiated metabolites. [3H]Histamine given intracisternally produced only trace amounts of oxidative metabolites. Formation of IAA, a potent GABA-A agonist with numerous neurochemical and behavioral effects, from minute quantities of histamine in brain indicates a need for reevaluation of histamine's metabolic pathway or pathways in brain and suggests a novel mechanism for interactions between histamine and the GABAergic system.

Animals↗
PubMed1995

Function of phytochrome A in potato plants as revealed through the study of transgenic plants.

We have generated transgenic potato plants (Solanum tuberosum) containing the potato phytochrome protein encoded by the PHYA gene cDNA (phyA) in sense or antisense orientation under the control of the 35S cauliflower mosaic virus promoter. Plants with increased and decreased phyA levels were analyzed. When grown under white light, development and growth of sprouts and plants were barely distinguishable from wild type. Under continuous far-red light, stem extension, leaf expansion, and hook opening of sprouts were accelerated in phyA overexpressors and delayed in antisense plants. Sprouts with reduced phyA levels were less sensitive to red light with regard to stem extension and expression of the small subunit genes for ribulose bisphosphate carboxylase. Under low red light:far-red light ratios, increased phyA levels reduced the stem extension component of the shade-avoidance response, whereas decreased levels led to an increase in the response.

Amino Acid Sequence↗
PubMed1995

Properties of a resiniferatoxin-stimulated, calcium inhibited but phosphatidylserine-dependent kinase, which is distinct from protein kinase C isotypes alpha, beta 1, gamma, delta, epsilon and eta.

We have separated a resiniferatoxin-stimulated histone-kinase activity from human neutrophils, elicited mouse macrophages and murine alveolar macrophages by hydroxyapatite chromatography. The assay conditions for resiniferatoxin kinase were optimized as part of this study and in the presence of phosphatidylserine but absence of Ca2+ the Ka for histone IIIs phosphorylation by resiniferatoxin was calculated as 16 nM. Using a phosphate gradient of 20-500 mM, peaks of protein kinase C activity could be washed from the hydroxyapatite column in 300 nM phosphate and resiniferatoxin kinase recovered in 500 mM phosphate. At the optimum concentration of 160 nM, the ability of resiniferatoxin to induce enzyme activity was compared with a range of phorbol esters all at the same concentration. These related compounds failed to activate resiniferatoxin kinase although they have previously been shown to activate protein kinase C isotypes. Similarly sn-1,2,-dioleoylglycerol and the potent irritant capsaicin at 30 microM failed to activate the kinase. A Scatchard analysis of [3H] phorbol dibutyrate binding produced a linear plot (Kd 41.6 nM; Bmax 11.6 fmol unit-1) and binding was inhibited by resiniferatoxin and 12-O-tetradecanoylphorbol-13-acetate (TPA), with resiniferatoxin 700 times more potent than TPA in this respect. A radiolabelled resiniferatoxin binding assay was also used to demonstrate specific binding of [3H]resiniferatoxin which could be inhibited by unlabelled compound. Resiniferatoxin kinase activity was shown to be distinct from the protein kinase C isotypes alpha, beta 1, gamma, delta and epsilon by means of immunological analysis and from the eta isotype, because that isotype was not stimulated by resiniferatoxin but was stimulated by TPA when a pseudosubstrate was used. In addition the resiniferatoxin-stimulated activity was inhibited in-vitro by the addition of Ca2+ (Ki 0.1-0.5 nM free Ca2+). Further purification of resiniferatoxin kinase by Superose chromatography indicated a major activity fraction of about 70-90 kDa. Thus resiniferatoxin kinase, isolated from human and mouse inflammatory cells is distinct from the known isotypes of protein kinase C and is a major resiniferatoxin receptor.

Animals↗
PubMed1994

Structure of hydrated layers on silicate electrode glasses.

The structural changes of the silicate framework in hydrated layers of silicate electrode glasses compared with untreated glasses as well as the quality and quantity of water and its ionic species stored in the layer have been investigated by high-resolution solid-state nuclear magnetic resonance (NMR) techniques [29Si magic-angle spinning (MAS), 29Si cross-polarization (CP) MAS, 1H high-speed MAS, 1H CRAMPS and 1H Echo NMR]. To support the results, infrared (IR) spectroscopy, thermal analysis and sodium ion concentration analyses were used. It was found that at least two different water species exist in the hydrated layer: SiOH groups and not very mobile hydrogen-bonded molecular water. Concerning the framework modified, Q3 groups [(SiO)3SiOH] were formed in the hydrated glass. During the swelling process a condensation of silanol groups formed took place to a great extent.

Electrodes↗
PubMed1994

Mixing the genders, an ethical dilemma: how nursing theory has dealt with sexuality and gender.

As nursing moves towards a holistic approach to care, its publications on sexuality have proliferated. 'Sexuality' and 'Gender' are concepts which are extremely difficult to define. While sex refers to the physical differences of the body, gender concerns the psychological and sociocultural differences between females and males. This distinction between sex and gender is fundamental, since many differences between females and males are not biological in origin. And, when a person's gender and sex fall together in accordance with social norms, it may not necessarily be a similar correlation for every individual. The nature of these similarities is essentially threefold. First, Thomas, Savage and Webb accept that there should be a nursing definition of sexuality. In different ways they acknowledge and refer to it as an integral part of a person's being and self concept. Secondly, the authors underline some of the complexities and difficulties nurses have defining and dealing with it in professional relationships as well as on the level of self reflection, knowledge, attitudes and beliefs. Thirdly, all three surveys show why such difficulties prevail, and go on to make suggestions for change in nursing interventions and training. This article summarizes these contributions and discusses the ethical problems which nurses face in dealing with the sexuality of their patients.

Behavior Control↗
PubMed1994

Ureaplasma urealyticum in Reiter's syndrome.

OBJECTIVE: To evaluate the role of Ureaplasma urealyticum (Uu) in the pathogenesis of Reiter's syndrome (RS). METHODS: Infection with Uu was determined in 31 patients with RS and 28 patients with other arthritides by urethral, cervical and synovial fluid (SF) culture and by measuring anti-Uu serum antibody. Infection with Chlamydia trachomatis was determined by examining SF by a direct immunofluorescence technique, by a polymerase chain reaction and by measuring anti-C. trachomatis serum antibody. The proliferative response of SF and peripheral blood mononuclear cells (PBMC) to Uu antigens in patients with RS was compared to that of a control group. The effect that treatment of 6 patients with RS with ciprofloxacin had on repeated cultures, on titer of anti-Uu antibody and on mononuclear cell reactivity was measured sequentially. RESULTS: The colonization rate of Uu in patients with RS (74%) was significantly greater than in patients with other arthritides (14%). Genital C. trachomatis isolation and serum anti-C. trachomatis antibody were uncommon in both groups (11 and 13%, respectively). SF mononuclear cells of the patients with RS proliferated specifically in response to Uu antigens [up to 6.9 stimulation index (SI)], as did their PBMC (up to 14.5 SI). In some patients, high anti-Uu antibody titers were measured in the serum. Clinical remission was observed in 4 of 6 patients and correlated with eradication of Uu, decrease in antibody titers and disappearance of mononuclear cell reactivity to Uu antigens. CONCLUSION: Our findings suggest that Uu might be a causative agent or a trigger in the development of sexually acquired RS.

Adult↗