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Biomedical subjects

S Davis

Publications and source records attributed to S Davis.

At least 91 records · Page 5Linked to original sources
PubMed2001

Lhermitte-Duclos disease associated with Cowden's syndrome: case report and literature review.

Lhermitte-Duclos disease (LDD) is a rare entity that may occur in the setting of Cowden's syndrome (CS). Accurate preoperative diagnosis can be made on the characteristic CT and MR appearances, thereby obviating the need for biopsy. It is important to be aware of the link between LDD and CS so that appropriate genetic counselling and tumour surveillance can be undertaken.

Adult↗
PubMed2001

Health providers' opinions on provider-client relations: results of a multi-country study to test Health Workers for Change.

A multi-centre study in four African countries was undertaken to test the acceptability and effectiveness of Health Workers for Change, a methodology to explore provider-client relations within a gender-sensitive context. This intervention addresses the interpersonal component of quality of care. The methodology, consisting of six workshops, was implemented by research teams in Zambia, Senegal, Mozambique and Uganda. It was found to be acceptable within in a range of cultural and primary health care settings. The workshops allowed difficult issues such as prejudice and bribery to be discussed openly, fostered problem solving and the development of practical plans to address problems that could strengthen district health systems.

Attitude of Health Personnel↗
PubMed2001

Analysis of the effects of deep mechanical massage in the porcine model.

Deep mechanical massage has been advocated as an alternative or adjunctive therapy for the contouring of subcutaneous fat and as a treatment for cellulite. We evaluated the effects of deep mechanical massage using two pig models. Yucatan pigs were divided into three groups (n = 4). One side of each body received 4, 10, or 20 treatments and the other side served as a control. Full-thickness tissue sections, including the underlying muscle, were harvested from identical treated and untreated regions. Examination of these regionally matched samples revealed an accumulation of dense, longitudinal collagen bands in the middle dermal and deep subdermal regions, which progressively increased with the number of treatments. Distortion and disruption of adipocytes was noted. In Yorkshire pigs, force-transducing balloon catheters were surgically placed between the deep subcutaneous tissue and muscle fascia. Catheters were inserted into two regions with different skin and subcutaneous tissue characteristics, the midflank and the hip. Standardized maneuvers were performed at suction settings 3, 5, 7, and 9 to record baseline tissue forces. Each maneuver carried a unique force signature. The measurement of tissue forces was repeated on the opposite side after 10 standardized treatment sessions. Analysis showed a significant reduction of measured forces at the midflank after the treatments. The actual force measured with each particular maneuver varied between different operators but not with different suction settings, suggesting that the technique of administering the treatments is the primary factor in creating the force within the tissue. This leads to the conclusion that deep mechanical massage is highly dependent on the individual operator of the device.

Adipose Tissue↗
PubMed2001

Dietary soy has both beneficial and potentially adverse cardiovascular effects: a placebo-controlled study in men and postmenopausal women.

To address the cardiovascular effects of dietary soy containing phytoestrogens, we measured blood pressure (BP), lipids, vascular function (systemic arterial compliance and pulse wave velocity), and endothelial function (flow-mediated vasodilation) in a randomized, double-blind trial. Two hundred thirteen healthy subjects (108 men and 105 postmenopausal women), 50-75 yr old, received either soy protein isolate (40 g soy protein, 118 mg isoflavones) or casein placebo for 3 months. There were 34 withdrawals (16%), with 179 subjects (96 men and 83 women) completing the protocol. After intervention in the soy group, compared with casein placebo, urinary phytoestrogens increased, accompanied by a significant fall in BP reflected by the BP model (P < 0.01) encompassing mean change (+/-SEM) in systolic (-7.5 +/- 1.2 vs. -3.6 +/- 1.1 mm Hg, P < 0.05), diastolic (-4.3 +/- 0.8 vs. -1.9 +/- 0.7 mm Hg, P < 0.05), and mean BP (-5.5 +/- 1 vs. -0.9 +/- 1 mm Hg, P < 0.008). In the lipid model, soy induced greater changes, compared with placebo (P < 0.001). On individual analysis, significant contributors included a reduction in the low- to high-density lipoprotein ratio (-0.33 +/- 0.1 vs. 0.04 +/- 0.1 mmol/L, P < 0.05) and triglycerides (-0.2 +/- 0.05 vs. -0.01 +/- 0.05 mol/L, P < 0.05) and an increase in Lp(a) lipoprotein (+/- 95% confidence interval) [42 (range, 17-67) vs. 4 (range, -22-31) mg/L, P < 0.05], whereas total, low-density lipoprotein, and high-density lipoprotein cholesterol improved in both groups; but no treatment effect was demonstrated. The arterial functional model demonstrated no difference between groups; although again, overall function improved in both groups. On individual analysis, peripheral PWV (reflecting peripheral vascular resistance) improved with soy (P < 0.01), whereas flow-mediated vasodilation (reflecting endothelial function) declined (in males only), compared with casein placebo (P < 0.02). No effect of treatment on the hypothalamic-pituitary-gonadal axis was noted in males or females. In normotensive men and postmenopausal women, soy improved BP and lipids but, overall, did not improve vascular function. Potential adverse effects were noted, with a decline in endothelial function (in males only) and an increase in Lp(a). Further research in hypertensive and hyperlipidemic populations is needed.

Aged↗
PubMed2001

Telemedicine in the Michigan Upper Peninsula region: an evaluation of the first five years.

A telemedicine network has operated in the Upper Peninsula (UP) region of Michigan since 1995. The Marquette General Health System (MGHS) is the tertiary hospital that provides telemedicine services to 14 surrounding rural health facilities and another seven clinics. In order to assess the state of telemedicine in the UP region and its potential for development, three main factors were assessed: organizational development, telemedicine activity and perceptions of the key players. Data were collected through interviews with five MGHS telemedicine staff, 10 physicians (five from the MGHS and five from surrounding rural areas), 13 of the 14 chief executive officers (CEOs) of the remote telemedicine sites and a survey of 21 telemedicine site coordinators. This information was analysed in order to outline job roles and responsibilities; to document the process of doing telemedicine; and to understand current policies and procedures. Telemedicine activity from 1995 to 1999 was analysed in terms of the purpose of the session. In 1999, a total of 515 telemedicine sessions were conducted, 323 being non-educational and 192 being educational. Most CEOs of the rural hospitals were interested in furthering their use of clinical telemedicine applications. The data also indicated a great need for education, particularly of the rural physicians. The overall view of those surveyed about MGHS's telemedicine programme was positive. Respondents were quick to compliment the staff whenever possible. New telemedicine staff have been employed, which will allow responsibilities to be reassigned in such a way as to create a more efficient system.

Attitude of Health Personnel↗
PubMed2001

Measuring temporal variability in residential magnetic field exposures.

Considerable interest has developed during the past ten years regarding the hypothesis that living organisms may respond to temporal variability in ELF magnetic fields to which they are exposed. Consequently, methods to measure various aspects of temporal variability are of interest. In this paper, five measures of temporal variability were examined: Arithmetic means (D(mean)) and rms values (D(rms)) of the first differences (i.e., absolute value of the difference between consecutive measurements) of magnetic field recordings; "standardized" forms of D(rms), denoted RCMS, obtained by dividing D(rms) by the standard deviations of the magnetic field data; and mean (F(mean)) and rms (F(rms)) values of fractional first differences. Theoretical investigations showed that D(mean) and D(rms) are virtually unaffected by long-term systematic trends (changes) in exposure. These measures thus provide rather specific measures of short-term temporal variability. This was also true to a lesser extent for F(mean) and F(rms). In contrast, the RCMS metric was affected by both short-term and long-term exposure variabilities. The metrics were also investigated using a data set consisting of twice-repeated two-calendar-day recordings of bedroom magnetic fields and personal exposures of 203 women residing in the western portion of Washington State. The predominant source of short-term temporal variability in magnetic field exposures arose from the movement of subjects through spatially varying magnetic fields. Spearman correlations between TWA bedroom magnetic fields or TWA personal exposures and five measures of temporal variability were relatively low. Weak to moderate levels of correlation were observed between temporal variability measured during two different sessions separated in time by 3 or 6 months. We conclude that first difference and fractional difference metrics provide specific and fairly independent measures of short-term temporal variability. The RCMS metric does not provide an easily interpreted measure of short-term or long-term temporal variability. This last result raises uncertainties about the interpretation of published studies that use the RCMS metric.

Air Pollution, Indoor↗
PubMed2001

Testosterone deficiency in women.

Testosterone (T) is an important component of female sexuality, enhancing interest in initiating sexual activity and response to sexual stimulation. Testosterone is also associated with greater well-being and with reduced anxiety and depression. Clinical and biochemical definitions of T deficiency have not been established; hence, the prevalence of this condition is not known. However, surgically menopausal women are among the populations most likely to experience T deficiency, a syndrome characterized by blunted or diminished motivation; persistent fatigue; decreased sense of personal well-being; sufficient plasma estrogen levels; and low circulating bioavailable T (either a low total T/sex hormone binding globulin (SHBG) ratio or free T in the lower one-third of the female reproductive range); and low libido. Exogenous estrogen, particularly when administered orally, increases SHBG, which, in turn, reduces free T and estradiol (E2). After oophorectomy, levels of T and its precursor, androstenedione, decline by approximately 50%. T replacement continues to be evaluated as an adjunct to estrogen replacement therapy, particularly for women with androgen deficiency symptoms, surgically menopausal women and women with premature ovarian failure. In the United States, oral methyltestosterone is the common product currently approved for androgen replacement in women. The best product specifically designed for women has yet to be determined, as standardized, long-term, randomized, control clinical studies are lacking and product refinement continues.

Estrogen Replacement Therapy↗
PubMed2001

National Institute of Mental Health Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE): Alzheimer disease trial methodology.

The authors describe the development of the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) protocol for Alzheimer disease (AD), a trial developed in collaboration with the National Institute of Mental Health (NIMH), assessing the effectiveness of atypical antipsychotics for psychosis and agitation occurring in AD outpatients. They provide an overview of the methodology utilized in the trial as well as the clinical-outcomes and effectiveness measures that were implemented.

Aged↗
PubMed2000

Neurological manifestations of enterovirus 71 infection in children during an outbreak of hand, foot, and mouth disease in Western Australia.

Enterovirus 71 (EV71) causes epidemics of hand, foot, and mouth disease associated with neurological complications in young children. We report an outbreak of EV71-associated neurological disease that occurred from February through September 1999 in Perth, Western Australia. Fourteen children with culture-proven, EV71-induced neurological disease were identified. Nine patients (64%) developed severe neurological disease; 4 of these patients developed long-term neurological sequelae. Neurological syndromes included aseptic meningitis, Guillain-Barré syndrome, acute transverse myelitis, acute cerebellar ataxia, opso-myoclonus syndrome, benign intracranial hypertension, and a febrile convulsion. Clinical and magnetic resonance imaging data indicated that immunopathology was a major factor in the pathogenesis of neurological disease in this outbreak. This finding is in contrast to reports of previous EV71 epidemics, in which virus-induced damage to gray matter was the most frequent cause of neurological disease.

Acute Disease↗
PubMed2000

Trends in the rate of emergency room admissions for preventable cardiovascular conditions among african american men and women over the past decade. Continuation of negative trends.

PURPOSE: The objective of this retrospective analysis was to compare secular changes in the rate of emergency room admissions (per 100,000) for selected acknowledged preventable cardiovascular conditions among African Americans (AA) men and women aged >/=21 from 1991-1998, and rate of change for Caucasian (Cau), Hispanic (Hisp), and Asian (Asi) men and women aged >/=21; conditions included angina, congestive heart failure (CHF), diabetes, and hypertension.METHODS: Results are derived from calendar-year California hospital data based on a selection of specified ICD-9 codes that correspond to the principal diagnosis for admission. The combined study sample size included a total of 21,016 individuals who were admitted to a hospital via the ER. Separate standardized and age-adjusted Poisson regression models were employed for each condition to assess race and time main effects and race x time interaction terms (P </= 0.01). Age and payer-source were entered as covariates to control for confounding effects. Men and women were analyzed separately.RESULTS: Mean overall rates of ER admission due to angina were significantly lower among AA men compared to Cau men (17.8 vs 18.2); however, rates were higher among Hisp and Asi men (6.03 and 7.1, respectively). Rates for CHF were higher among AA men compared to Cau, Hisp, and Asi men (23.7 vs, 11.0, 3.7, 4.8, respectively); similar results were observed for diabetes (8.6 vs 2.7, 2.3, 1.2, respectively) and hypertension (5.1 vs, 1.6, 0.9, 1.5, respectively). Differentials in 1991 resulted in widening disparities overtime for each condition. For women, mean overall rates due to angina were significantly higher among AA women compared Cau, Hisp, and Asi women (17.0 vs 13.5, 5.7, 5.7, respectively). Similar patterns were observed for CHF (23.1 vs, 11.0, 3.7, 4.8, respectively), diabetes (6.4 vs 2.0, 1.8, 1.1, respectively) and hypertension (5.8 vs 1.9, 1.1, 1.5), respectively). As observed among AA men, differentials in 1991 resulted in widening disparity overtime.CONCLUSIONS: Findings reveal higher rates of ER admissions for preventable cardiovascular conditions among AA men and women during the 1990s with evidence of widening health status disparities into the new millennium.

Journal Article↗
PubMed2000

Vascular-specific growth factors and blood vessel formation.

A recent explosion in newly discovered vascular growth factors has coincided with exploitation of powerful new genetic approaches for studying vascular development. An emerging rule is that all of these factors must be used in perfect harmony to form functional vessels. These new findings also demand re-evaluation of therapeutic efforts aimed at regulating blood vessel growth in ischaemia, cancer and other pathological settings.

Angiopoietin-2↗
PubMed2000

The MAPK/ERK cascade targets both Elk-1 and cAMP response element-binding protein to control long-term potentiation-dependent gene expression in the dentate gyrus in vivo.

The mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling cascade contributes to synaptic plasticity and to long-term memory formation, yet whether MAPK/ERK controls activity-dependent gene expression critical for long-lasting changes at the synapse and what the events underlying transduction of the signal are remain uncertain. Here we show that induction of long-term potentiation (LTP) in the dentate gyrus in vivo leads to rapid phosphorylation and nuclear translocation of MAPK/ERK. Following a similar time course, the two downstream transcriptional targets of MAPK/ERK, cAMP response element-binding protein (CREB) and the ternary complex factor Elk-1, a key transcriptional-regulator of serum response element (SRE)-driven gene expression, were hyperphosphorylated and the immediate early gene zif268 was upregulated. The mRNA encoding MAP kinase phosphatase MKP-1 was upregulated at the time point when MAPK/ERK phosphorylation had returned to basal levels, suggesting a negative feedback loop to regulate deactivation of MAPK/ERK. We also show that inhibition of the MAPK/ERK cascade by the MAPK kinase MEK inhibitor SL327 prevented CREB and Elk-1 phosphorylation, and LTP-dependent gene induction, resulting in rapidly decaying LTP. In conclusion, we suggest that Elk-1 forms an important link in the MAP kinase pathway to transduce signals from the cell surface to the nucleus to activate the genetic machinery necessary for the maintenance of synaptic plasticity in the dentate gyrus. Thus, MAPK/ERK activation is required for LTP-dependent transcriptional regulation and we suggest this is regulated by two parallel signaling pathways, the MAPK/ERK-Elk-1 pathway targeting SRE and the MAPK/ERK-CREB pathway targeting CRE.

Animals↗