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Biomedical subjects

J Davis

Publications and source records attributed to J Davis.

At least 127 records · Page 7Linked to original sources
PubMed2000

A randomised comparison and economic evaluation of laparoscopic-assisted hysterectomy and abdominal hysterectomy.

OBJECTIVES: To determine the safety, cost effectiveness and effect on quality of life of laparoscopic-assisted vaginal hysterectomy (LAVH) compared with total abdominal hysterectomy (TAH) in the management of benign gynaecological disease. DESIGN: Randomised controlled trial and economic evaluation. SETTING: Three hospitals in the West of Scotland. PARTICIPANTS: Two hundred women scheduled for an abdominal hysterectomy for benign gynaecological disease. MAIN OUTCOME MEASURES: Conversion rate of LAVH to TAH, complication rates, NHS resource use and costs, quality of life using EuroQol 5 D visual analogue scale, and achievement of milestones. RESULTS: The overall incidence of operative complications was 14% in the TAH group and 8% in the LAVH group, with an 8% conversion rate. Length of operation was significantly greater in the women having LAVH at 81 +/- 30 min vs 47 +/- 16 min (P < 0.001). There was no difference in analgesic requirements between the groups although there was a significantly shorter hospital stay for those having LAVH. The rate of post-surgery recovery, satisfaction with operation and quality of life at four weeks post-operative were similar in the two groups of women. LAVH was significantly more expensive than TAH and remained more expensive for all but the most extreme scenario. CONCLUSIONS: This study demonstrates that despite the decreased length of hospital stay, LAVH is more expensive than TAH. In addition, recovery following operation and patient satisfaction were not affected by the route chosen. It is unlikely that LAVH represents an efficient use of NHS resources.

Adult↗
PubMed2000

Cerebrovascular smooth muscle cell surface fibrillar A beta. Alteration of the proteolytic environment in the cerebral vessel wall.

Cerebrovascular deposition of the amyloid beta-protein (A beta) is a common pathologic event in patients with Alzheimer's disease (AD) and certain related disorders including hereditary cerebral hemorrhage with amyloidosis Dutch-type (HCHWA-D). A beta deposition occurs primarily in the medial layer of the cerebral vessel wall in an assembled fibrillar state. These deposits are associated with several pathological responses including degeneration of the smooth muscle cells in the cerebral vessel wall. Severe cases of cerebrovascular A beta deposition are also accompanied by loss of vessel wall integrity and hemorrhagic stroke. Although the reasons for this pathological consequence are unclear, altered proteolytic mechanisms within the cerebral vessel wall may be involved. Recent studies from our laboratory have shown that cell-surface assembly of A beta into fibrillar structures causes cellular degeneration via an apoptotic pathway and creates an altered proteolytic microenvironment on the cell surface of human cerebrovascular smooth muscle cells (HCSM cells). For example, HCSM cell-surface A beta fibrils serve as a site for tight binding of cell-secreted amyloid beta-precursor protein (A beta PP). Since A beta PP is a potent inhibitor of key proteinases of coagulation cascade, its enhanced localization on the A beta fibrils would provide an strong anticoagulant environment. In addition, HCSM cell-surface A beta fibrils are potent stimulators of tissue plasminogen activator (tPA) creating a profibrinolytic milieu. Our findings indicate that A beta fibril assembly on the HCSM cell surface causes cellular degeneration and results in both a strong anticoagulant and fibrinolytic environment. Together, these altered proteolytic events could create a setting that is conducive to loss of vessel wall integrity and hemorrhagic stroke.

Alzheimer Disease↗
PubMed2000

Utility of tissue culture for detection of Toxoplasma gondii in vitreous humor of patients diagnosed with toxoplasmic retinochoroiditis.

Laboratory recovery and confirmation of the etiologic agent in necrotizing retinochoroiditis are problematic. Tissue culture and intraocular antibody titers were compared as adjuncts to clinical diagnosis for toxoplasmic retinochoroiditis: the correlations were 91 and 67%, respectively. Isolation of Toxoplasma gondii may establish a definitive diagnosis in patients with toxoplasmic retinochoroiditis.

Animals↗
PubMed2000

Differential role of melanocortins in mediating leptin's central effects on feeding and reproduction.

Leptin serves as a humoral link coupling the status of energy reserves to the functional activity of the reproductive system. Leptin is thought to act through melanocortinergic pathways in the brain to regulate ingestive behaviors; however, whether melanocortins mediate leptin's actions on the neuroendocrine-reproductive axis is unknown. We tested this hypothesis first by determining whether the effects of leptin on feeding behavior and reproduction in the ob/ob mouse could be blocked by the melanocortin receptor (MC-R) antagonist SHU9119 and second, by examining the effects of the MC-R agonist MTII on feeding and the endocrine-reproductive system. Administered by intracerebroventricular injections, leptin inhibited food intake, raised plasma gonadotropin levels, and increased seminal vesicle weights compared with controls; SHU9119 (intracerebroventricularly) attenuated leptin's effects on food intake and body weight but did not alter leptin's stimulatory effect on the reproductive axis. MTII (intracerebroventricularly and intraperitoneally) decreased food intake and increased body temperature compared with controls but had no effect on the reproductive-endocrine axis. These results suggest that although leptin acts centrally through melanocortinergic pathways to inhibit ingestive behaviors and stimulate metabolism, leptin's activational effect on the reproductive axis is likely to be mediated by other, unknown neuroendocrine circuits.

Animals↗
PubMed2000

The effects of norepinephrine infusion on the circulating lymphocyte counts of post-open heart surgery patients.

In this retrospective study employing chart reviews, 75 open heart surgery patients (OHSPs) were divided into 3 groups of 25 patients. Group 1 received no intravenous (i.v.) norepinephrine (NE) after surgery. Group 2 and group 3 received a minimum of 0.028 mcg/kg/min of i.v. NE for 6-24 h and greater than 24 h, respectively. In the 3 groups, preoperative lymphocyte counts were compared to counts obtained on postoperative days 1 and 2. The results showed lower lymphocyte counts on postoperative day 2 in group 3 subjects, who received NE for 24 h or more, compared to subjects of the other groups who received no NE or 6-24 h of NE (p < 0.05). There was also evidence that preoperative use of beta-blocking agents significantly affected the change in lymphocyte counts from day 1 to day 2 in both groups receiving NE. Furthermore, postoperative infections were more prevalent in group 3 than the other 2 groups (p < 0.05). The lower lymphocyte counts and higher infection rate, however, may be linked to lower postoperative blood pressure and increased number of intensive care unit days in group 3. Further investigation is warranted to elucidate the effects of i.v. NE administration on the lymphocyte counts of OHSPs and to reduce infections in those receiving NE.

Adrenergic beta-Antagonists↗
PubMed2000

Biologic mechanisms of 89SrCl2 incorporation into type I collagen during bone mineralization.

UNLABELLED: 89SrCl2 is currently used as a palliative treatment for painful osseous metastases associated with an osteoblastic reaction in bone. However, the underlying biologic mechanism by which 89SrCl2 accumulates at these lesions and mediates palliation remains unclear. The aim of this study was therefore to elucidate this mechanism. METHODS: An in vitro cell biologic model, incorporating the MC3T3-E1 murine osteoblast cell line, was established to replicate the process of collagen production and mineralization. Experiments were performed to investigate the cellular association of 89SrCl2 and 45CaCl2 with both MC3T3-E1 cells and the PC-3 human prostate adenocarcinoma cell line. RESULTS: No evidence of intracellular localization of 89SrCl2 or 45CaCl2 was found for either cell line. Localization of radiolabel was seen to be associated with MC3T3-E1 cells but only in cultures that had undergone both differentiation and mineralization. The association of 89SrCl2 was inhibited by the alkaline phosphatase inhibitor levamisole, and extracellular localization of 89SrCl2 was confirmed by microautoradiography. CONCLUSION: 89SrCl2 acts as a calcium mimic and, as such, becomes associated with the collagen matrix produced by the MC3T3-E1 cells during collagen mineralization.

Animals↗
PubMed2000

Human and behavioral factors contributing to spine-based neurological cockpit injuries in pilots of high-performance aircraft: recommendations for management and prevention.

In high-performance aircraft, the need for total environmental awareness coupled with high-g loading (often with abrupt onset) creates a predilection for cervical spine injury while the pilot is performing routine movements within the cockpit. In this study, the prevalence and severity of cervical spine injury are assessed via a modified cross-sectional survey of pilots of multiple aircraft types (T-38 and F-14, F-16, and F/A-18 fighters). Ninety-five surveys were administered, with 58 full responses. Fifty percent of all pilots reported in-flight or immediate post-flight spine-based pain, and 90% of fighter pilots reported at least one event, most commonly (> 90%) occurring during high-g (> 5 g) turns of the aircraft with the head deviated from the anatomical neutral position. Pre-flight stretching was not associated with a statistically significant reduction in neck pain episodes in this evaluation, whereas a regular weight training program in the F/A-18 group approached a significant reduction (mean = 2.492; p < 0.064). Different cockpit ergonomics may vary the predisposition to cervical injury from airframe to airframe. Several strategies for prevention are possible from both an aircraft design and a preventive medicine standpoint. Countermeasure strategies against spine injury in pilots of high-performance aircraft require additional research, so that future aircraft will not be limited by the human in control.

Adult↗
PubMed2000

Fire-based EMS.

Explore the source record for details and available documents.

Adolescent↗
PubMed2000

Violent thoughts and violent behavior following hospitalization for mental disorder.

Using a standardized schedule of questions, this study examined (a) the prevalence of self-report of violent thoughts by patients hospitalized for mental disorders compared with nonpatients, (b) the persistence of violent thoughts after discharge, and (c) the relation between patients' violent thoughts while hospitalized and violent acts within 20 weeks after hospital discharge. About 1/3 of the patients reported thoughts of violence while hospitalized, more than twice the proportion found among nonpatients. Reporting violent thoughts in hospital was significantly related to engaging in violent acts within 20 weeks after discharge for non-White patients, patients without major mental disorder but with substance abuse diagnoses, patients with high symptom severity, and patients whose reports of violent thoughts persisted after discharge. Reporting violent thoughts was significantly related to measures of psychopathy, anger, and impulsiveness.

Adult↗
PubMed2000

Genetic testing and screening in pediatric populations.

It is conceivable that in the near future a family could present themselves to their health care provider and request to be tested for diseases X, Y, and Z, equipped only with a web page listing of disease-causing genes. The testing of children suggests subtle and controversial inherent conflicts, however. Decisions about whether to provide genetic testing become increasingly murky for a health care professional as the requests advance from testing a child for carrier status for an autosomal recessive disorder, to testing a girl for a sex-linked mutation, to testing an asymptomatic child for a susceptibility to a particular disorder. Although no single case can exemplify every variable and circumstance confronting health care professionals today, this case-based discussion of x-linked severe combined immune deficiency can serve as a framework to examine some of the potential dilemmas surrounding the testing of children for genetic disorders.

Adolescent↗
PubMed2000

Self-care strategies to reduce fluid intake and control thirst in hemodialysis patients.

The purpose of this pilot study was to describe how often hemodialysis (HD) patients used particular self-care strategies to reduce fluid intake or relieve thirst, how effective each strategy was perceived to be, and whether they planned to use that strategy in the future. A cross-sectional descriptive design was used. The sample of 20 participants from one Midwest dialysis unit verbally responded to the self-care items that were presented. Most of these patients reported they regularly avoided the sun, took medications with mealtime fluid, limited salt on their foods, avoided salty foods, stayed busy, stayed away from fast food restaurants, drank ice-cold drinks, and drank only when thirsty to reduce fluid intake and relieve thirst. They also planned to use these strategies in the future. Interestingly, the strategies perceived as most effective--measuring daily allotted fluids in a pitcher to drink from all day, spacing liquids over the entire day, and measuring the amount of fluid they drank--were not the same as those they used most. Replication of these findings with larger samples is strongly recommended.

Adult↗
PubMed1999

Myelodysplastic and myeloproliferative disorders of childhood: a study of 167 patients.

Myelodysplastic syndromes (MDS) and myeloproliferative syndromes (MPS) of childhood are a heterogeneous group of clonal disorders of hematopoiesis with overlapping clinical features and inconsistent nomenclature. Although a number of genetic conditions have been associated with MDS and MPS, the overall contribution of inherited predispositions is uncertain. We report a retrospective study examining clinical features, genetic associations, and outcomes in 167 children with MDS and MPS. Of these patients, 48 had an associated constitutional disorder. One hundred one patients had adult-type myelodysplastic syndrome (A-MDS), 60 had juvenile myelomonocytic leukemia (JMML), and 6 infants with Down syndrome had a transient myeloproliferative syndrome (TMS). JMML was characterized by young age at onset and prominent hepatosplenomegaly, whereas patients with A-MDS were older and had little or no organomegaly. The most common cytogenetic abnormalities were monosomy 7 or del(7q) (53 cases); this was common both in patients with JMML and those with A-MDS. Leukemic transformation was observed in 32% of patients, usually within 2 years of diagnosis. Survival was 25% at 16 years. Favorable prognostic features at diagnosis included age less than 2 years and a hemoglobin F level of less than 10%. Older patients tended to present with an adult-type MDS that is accommodated within the French-American-British system. In contrast, infants and young children typically developed unique disorders with overlapping features of MDS and MPS. Although the type and intensity of therapy varied markedly in this study, the overall outcome was poor except in patients with TMS.

Child↗
PubMed1999

Insights into the mechanism by which inhibition of Na,K-ATPase stimulates aldosterone production.

Inhibition of Na,K-adenosine triphosphatase (Na,K-ATPase) activity by ouabain has been shown to increase the release of aldosterone from rat glomerulosa cells, but the mechanism by which this elevation of aldosterone production occurs has not been established. Small changes in membrane potential can significantly affect aldosterone release. Consequently, inhibition of Na,K-ATPase in glomerulosa cells may stimulate aldosterone production by membrane depolarization. If so, ouabain-stimulated production should be dependent on calcium influx through voltage-gated calcium channels. It has previously been shown that ouabain induces a moderately rapid increase in cytosolic calcium in rat glomerulosa cells. Therefore, in this study, we test whether ouabain stimulates aldosterone production with a time course consistent with early membrane depolarization as suggested by the previously reported early increase in cytosolic calcium. To study the time course of aldosterone production, we developed a perfusion technique that allows an examination of the initial effects of ouabain on aldosterone production. The results show that ouabain rapidly stimulates aldosterone production. Continuous perfusion with 0.25 or 1 mmol/L ouabain induced a brisk, robust increase in aldosterone production, followed by a decrease to near baseline over 60 minutes. Ouabain-stimulated aldosterone production was dependent on the presence of extracellular calcium and calcium influx through voltage-gated calcium channels. Our results support the hypothesis that the inhibition of Na,K-ATPase in rat adrenal glomerulosa cells immediately depolarizes the membrane potential and opens voltage-gated calcium channels.

Adrenal Glands↗