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Biomedical subjects

S Stark

Publications and source records attributed to S Stark.

At least 37 records · Page 2Linked to original sources
PubMed1998

Comparison of articulate brachiopod nuclear and mitochondrial gene trees leads to a clade-based redefinition of protostomes (Protostomozoa) and deuterostomes (Deuterostomozoa)

Nuclear and mtDNA sequences from selected short-looped terebratuloid (terebratulacean) articulate brachiopods yield congruent and genetically independent phylogenetic reconstructions by parsimony, neighbour-joining and maximum likelihood methods, suggesting that both sources of data are reliable guides to brachiopod species phylogeny. The present-day genealogical relationships and geographical distributions of the tested terebratuloid brachiopods are consistent with a tethyan dispersal and subsequent radiation. Concordance of nuclear and mitochondrial gene phylogenies reinforces previous indications that articulate brachiopods, inarticulate brachiopods, phoronids and ectoprocts cluster with other organisms generally regarded as protostomes. Since ontogeny and morphology in brachiopods, ectoprocts and phoronids depart in important respects from those features supposedly diagnostic of protostomes, this demonstrates that the operational definition of protostomy by the usual ontological characters must be misleading or unreliable. New, molecular, operational definitions are proposed to replace the traditional criteria for the recognition of protostomes and deuterostomes, and the clade-based terms 'Protostomoza' and 'Deuterostomozoa' are proposed to replace the existing term 'Protostomia' and 'Deuterostomia'.

Animals↗
PubMed1998

Prevalence of antibodies against virus-like particles of Epidermodysplasia verruciformis-associated HPV8 in patients at risk of skin cancer.

There is increasing evidence for widespread occurrences of infection with Epidermodysplasia verruciformis-related human papillomaviruses, both in the general population and in immunosuppressed patients. In order to test for the prevalence of antibodies directed against the native L1 epitopes exposed on the surface of the virions, we have established an IgG-specific enzyme-linked immunosorbent assay with L1 virus-like particles of the Epidermodysplasia verruciformis-specific human papillomavirus 8 as antigen to screen 567 representative serum samples from the general population and immunosuppressed/dermatologic patients. Among healthy European donors (n = 210), 7.6% were found to be seropositive. In a group of renal transplant recipients (n = 185) the antibody prevalence was elevated to 21.1%, irrespective of the presence or absence of skin cancer. High positivity rates could be detected among (i) immunocompetent patients with nonmelanoma skin tumors (45.6%, n = 79) and (ii) Psoralene/UVA treated psoriasis patients (42.9%, n = 42). In contrast, anti-human papillomavirus 8-virus-like particle antibodies were found in only 6.8% of Hodgkin lymphoma patients (n = 44).

Antibodies, Viral↗
PubMed1998

Alcoholism among indigent inpatients: identification and intervention by internal medicine residents.

BACKGROUND: This study examined alcoholism identification and interventions by internal medicine residents, determined the prevalence of alcoholism among indigent inpatients, and examined some variables related to alcoholism in this population. METHODS: The alcohol abuse and dependence section of the Diagnostic Interview Schedule was administered to 197 inpatients, and chart audits were done. RESULTS: The obtained prevalence of alcoholism was 17%. Residents identified current alcohol abuse among 71% of current alcoholics, 17% of past alcoholics, and 3% of nonalcoholics. Sixty-two percent of alcoholics identified by the residents did not receive advice or referral, 13% received advice, 17% were referred to Alcoholics Anonymous, and 8% were referred to an inpatient facility. CONCLUSIONS: Our results suggest that although residents' identification of alcoholism is satisfactory, it is necessary to improve their rates of intervention. The profile of the alcoholic inpatients in this study includes demographics, presence of chronic illnesses, and utilization of medical services as compared with nonalcoholics.

Adult↗
PubMed1998

Acidosis-induced metallothionein (MT) mRNA expression in neonatal rat primary astrocyte cultures.

Metallothionein (MT) mRNA levels were determined following exposure of neonatal rat primary astrocyte cultures to acidosis. Astrocyte total RNA was probed on northern blots with [alpha 32 P]dCTP-labeled synthetic cDNA probes specific for rat MT isoform mRNAs. The probe for MT-I mRNA hybridized to a single mRNA with a size appropriate for MT, approximately 550 nucleotides. MT-I mRNA levels in astrocyte monolayers exposed to pH 6.5 and 6.0 for 3 or 6 hours were unchanged compared with MT-I mRNA levels in control cultures exposed to pH 7.4. In contrast, 9 hour exposure of astrocytes to pH 6.5 and 6.0 led to a significant increase in MT-I mRNA transcripts compared with controls maintained at pH 7.4 (p < 0.001 and p < 0.02, respectively). A probe for MT-II mRNA that hybridizes to a single mRNA (450 nucleotides) was also used to determine the effect of acidosis on astrocyte MT-II mRNA transcripts. Although statistical significance was not attained, a similar trend was noted, with a 9 hour exposure to pH of 6.5 and 6.0 resulting in increased astrocytic expression MT-II mRNA compared with control cells maintained at pH 7.4. Acidosis was also associated with a pH-dependent increase in astrocytic volume. Accordingly, acidosis is invoked as an added stimulus to stress factors associated with the induction of astrocytic MT mRNA transcripts.

Acidosis↗
PubMed1997

Binding of aminoalkylindoles to noncannabinoid binding sites in NG108-15 cells.

1. Aminoalkylindoles, typified by WIN 55212-2, bind to G protein-coupled cannabinoid receptors in brain. Although cannabinoids inhibit adenylyl cyclase in NG108-15 neuroblastoma x glioma hybrid cells, cannabinoid receptor binding in these cells has not been described previously. This study compares pharmacological characteristics of [3H]WIN 55212-2 binding sites in rat cerebellar membranes and in NG108-15 membranes. 2. Although the KD of specified [3H]WIN 55212-2 binding was similar in brain and NG108-15 membranes, the Bmax was 10 times lower in NG108-15 than in cerebellar membranes. In both brain and NG108-15 membranes, aminoalkylindole analogues were relatively potent in displacing [3H]WIN 55212-2 binding. However, IC50 values for more traditional cannabinoids were significantly higher in NG108-15 membranes than in brain, e.g., the Ki values for CP55,940 were 1.2 nM in brain and > 5000nM in NG108-15 membranes. Moreover, sodium and GTP-gamma-S decreased [3H]WIN 55212-2 binding in brain but not in NG108-15 membranes. 3. These data suggest that WIN 55212-2 does not label traditional cannabinoid receptors in NG108-15 cells and that these novel aminoalkylindole binding sites are not coupled to G proteins.

Analgesics↗
PubMed1997

[Adrenal gland incidentaloma is not a "time bomb"--arguments for follow-up control].

Adrenal masses are nowadays more and more diagnosed incidentally. In the vast majority of cases these "incidentalomas" are benign adrenocortical adenomas which do not compel operative therapy. In about 12% of patients an endocrine activity is detected. With Increasing tumor size the risk of malignancy increases. This article summarizes recommendations, only to allow patients with endocrine activity or an increased risk of malignancy to be selected for surgery. A small uncertainty will always remain, but may be minimized by an individually tailored follow-up.

Adrenal Gland Neoplasms↗
PubMed1996

Cannabinoid receptor stimulation of guanosine-5'-O-(3-[35S]thio)triphosphate binding in rat brain membranes.

Cannabinoid receptors belong to the class of G-protein-coupled receptors which inhibit adenylyl cyclase. Coupling of receptors to G-proteins can be assessed by the ability of agonists to stimulate guanosine-5'-O-(3-[35S]thio)triphosphate ([35S]GTP gamma S) binding in the presence of excess GDP. The present study examined the effect of cannabinoid agonists on [35S]GTP gamma S binding in rat brain membranes. Assays were conducted with 0.05 nM [35S]GTP gamma S, incubated with rat cerebellar membranes, 1-30 microM GDP and the cannabinoid agonist WIN 55212-2. Results showed that the ability of WIN 55212-2 to stimulate [35S]GTP gamma S binding increased with increasing concentrations of GDP, with 10-30 microM GDP providing approximately 150-200% stimulation by the cannabinoid agonist. The pharmacology of cannabinoid agonist stimulation of [35S]GTP gamma S binding paralleled that of previously reported receptor binding and adenylyl cyclase assays, and agonist stimulation of [35S]GTP gamma S binding was blocked by the cannabinoid antagonist SR141716A. Brain regional studies revealed widespread stimulation of [35S]GTP gamma S binding by WIN 55212-2 in a number of brain areas, consistent with in vitro [35S]GTP gamma S autoradiography. These results demonstrate that [35S]GTP gamma S binding in the presence of excess GDP is an effective measure of cannabinoid receptor coupling to G-proteins in brain membranes.

Animals↗
PubMed1994

Project 2000 student wastage: a case study.

High wastage rates associated with the nursing profession were a contributory factor driving recent reforms in the form of Project 2000 (P2000). Such changes beg the question: to what extent has this new educational initiative affected current wastage patterns among nursing students? This paper examines whether or not this new initiative is having an effect on student wastage at a first-wave college of nursing, midwifery and health visiting which implemented P2000 in 1989. Thus far, 10 cohorts of students have been admitted on to the course, seven full-time and three part-time. It is hoped other institutions involved in nurse education and training may gain some beneficial insights from the lessons learnt and measures taken to stem wastage at the college described in this case study.

Adolescent↗
PubMed1994

A nurse tutor's experience of personal and professional growth through action research.

Action research is growing in popularity as an approach to research in the nursing profession. Action research seeks to engage practitioners collaboratively into taking action to improve their situation; therefore, one could argue it is ideally suited to nursing since it is a practice-based profession. This paper examines how the action research process, which is underpinned by self-reflection, has the potential to develop practitioners both professionally and personally. A nurse tutor's experience of engaging in action research for the first time is outlined. The paper includes extracts from the tutor's diary to provide an insight into how she experienced, in particular, self-reflection as part of her learning about action research. Her experience was initially painful, but over a few months it became pleasurable as she discovered the joy in initiating positive changes in her work as well as in herself.

Attitude of Health Personnel↗
PubMed1993

The antihypertensive efficacy and tolerability of a low dose combination of ramipril and felodipine ER in mild to moderate essential hypertension.

1. The antihypertensive efficacy and tolerability of a low dose combination of the angiotensin converting enzyme inhibitor ramipril (2.5 mg) and the extended release formulation of the dihydropyridine calcium channel antagonist felodipine (5 mg) were assessed in a double-blind, double dummy placebo controlled, randomised, crossover study in 20 patients (mean age 55.4 years; range 46-69) with uncomplicated mild to moderate hypertension (supine diastolic > 90 mmHg < 115 mmHg after 4 weeks of single-blind wash-out on placebo). The four randomised, double-blind, crossover study phases evaluated the response to 4 weeks of once daily treatment with placebo, monotherapy with each drug and the combination. Noninvasive ambulatory blood pressure monitoring (Spacelabs 90207) was performed for 24 h at the end of each phase. 2. The mean 24 h ambulatory blood pressure (mmHg) was 147.9/92.0 following placebo, 141.3/87.8 following monotherapy with ramipril 2.5 mg, 136.8/85.8 following monotherapy with felodipine ER 5 mg and 131.1/82.6 following the combination of ramipril 2.5 mg and felodipine ER 5 mg. All active treatment phases significantly reduced mean 24 h ambulatory diastolic pressure by comparison with placebo. The antihypertensive efficacy of the combination was additive. 3. The coadministration of ramipril did not attenuate the incidence of headache attributable to felodipine ER.

Aged↗
PubMed1993

Purification and characterization of the CA 125 tumor-associated antigen from human ascites.

CA 125 is an antigenic determinant associated with epithelial ovarian carcinomas, which is recognized by a monoclonal antibody, OC 125. The biochemical structure, the immunological characteristics and the physiological function of CA 125 are unknown, principally because the molecule expressing it has not been purified to homogeneity. In the present study, we developed a single, one-step method for purifying CA 125 by column affinity chromatography, using the OC 125 antibody as immobilized ligand. The column proved to be highly specific for the purification of CA 125 from human ascites (HA). The antigen that eluted from the column has a specific activity of 6,240 +/- 120 U of CA 125/mg protein, the specific activity in the initial HA samples being 100 +/- 12 U/mg protein. The purified, immunoreactive CA 125 (IR-CA 125) was shown to be proteinaceous in nature. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration characterization showed that the purified antigen exists as a high molecular weight (MW) complex, of up to 1.5 million daltons, which could be dissociated under strong denaturing conditions, giving rise to moieties with an apparent MW of 205 and 55 kD. IR-CA 125 was also associated with a lower MW protein, with an apparent MW of 10-15 kD. The 205-kD MW protein was immunoreactive CA 125, as measured by immunoradiometric assay after being electroeluted from the polyacrylamide gel. Furthermore, when the affinity-purified antigen was subjected to SDS-PAGE, followed by immunoblotting, the lane which was reactive with the iodinated OC 125 antibody gave rise to a band with a molecular mass of 205 kD. Our results suggest that, on an analytical scale, the affinity column is useful for the purification of CA 125. The purified antigen is being used to investigate the possible role of CA 125 in the growth, development and physiological characteristics of human ovarian carcinomas in in vitro studies.

Antibodies, Monoclonal↗
PubMed1991

Combined lipid-lowering and antihypertensive treatment as part of a strategy of multiple risk factor intervention.

Thirty-six patients with treated mild to moderate hypertension and hypercholesterolaemia (greater than 6.5 mmol/l) entered a 12 week study to evaluate the efficacy and patient tolerability of combined lipid-lowering and antihypertensive treatment as part of a strategy of multiple risk factor intervention. The principal effects on the plasma lipid profiles were significant reductions of 30-40% in total and LDL cholesterol. These reductions were achieved without loss of blood pressure control. There was no significant impact on HDL cholesterol or on lipoprotein Lp(a). These preliminary results suggest that substantial reductions in total and LDL cholesterol can be achieved without compromising blood pressure control which remained satisfactory at 144/82 supine and 143/80 mmHg standing. Furthermore, these changes were achieved without any problems of patient tolerability or interference with patient compliance with drug treatment. Overall, therefore, substantial reductions in CHD risk can be achieved with an acceptable combination of lipid lowering and antihypertensive treatments.

Aged↗
PubMed1985

Mechanism of alternating bundle branch aberrancy with atrial bigeminy: electrocardiographic-electrophysiologic correlates.

The mechanism of alternating bundle branch aberrancy in response to atrial bigeminy with fixed coupling intervals lacks adequate explanation. In this report, electrophysiologic studies on five patients with fixed coupled atrial bigeminy, identical impulse intervals arriving at the His bundle and alternating bundle branch aberrancy are presented. The mechanism of alternating bundle branch aberrancy in these patients appears to be alternating changes in the refractory periods of the bundle branches resulting from differences in the activation sequence of the distal bundle branches. These findings provide further insight into the mechanism of aberrant conduction.

Arrhythmias, Cardiac↗
PubMed1985

Unusual presentation of DDD pacemaker system malfunction.

A DDD pacemaker utilizing an atrial J electrode was implanted in a patient whose right atrial appendage had been removed 7 years prior during aortic valve replacement. Alternating QRS morphologies produced by pacemaker stimulus artifacts occurred as a consequence of atrial lead dislodgement. The screw-in atrial electrode has superior stability in patients with right atrial appendage removal; stability of the atrial J electrode cannot be obtained in such cases.

Electrocardiography↗
PubMed1983

Peripheral facial palsy with intact taste and tearing caused by intrapontine lesion.

Two patients with documented lesions in the floor of the fourth ventricle had unilateral paralysis of the upper and lower facial muscles but normal taste sensation and tearing function. These findings contradict the widely accepted clinical notion that an intraparenchymal lesion of the facial nerve invariably causes loss of gustatory and lacrimal function.

Brain Diseases↗