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Biomedical subjects

R Davis

Publications and source records attributed to R Davis.

At least 145 records · Page 8Linked to original sources
PubMed1998

Physical fitness: exercise prescription for older adults. 3.

Patients age 50 and older who are seen by primary care doctors are in various stages of wellness, ranging from healthy to frail. Because of this diversity, exercise prescription needs to be individualized, based on many of the same principles as drug prescription. Fitness programs typically include exercises to improve posture, aerobics, flexibility, strength, and balance. Exercising for 5 minutes a day is a good starting point, with sessions increasing gradually to 20 to 30 minutes. Trunk strengthening exercise can help patients stand from soft, low chairs. Ankle exercises can reduce the risk of falls and hip fractures. Weight training is safe and effective exercise for older patients.

Aged↗
PubMed1997

Gender gap in cystic fibrosis mortality.

The authors conducted the largest study to date of survival in cystic fibrosis. The study cohort consisted of all patients with cystic fibrosis seen at Cystic Fibrosis Foundation-accredited care centers in the United States between 1988 and 1992 (n = 21,047), or approximately 85% of all US patients diagnosed with cystic fibrosis. Cox proportional hazards regression analysis was used to compare the age-specific mortality rates of males and females and to identify risk factors serving as potential explanatory variables for the gender-related difference in survival. Among the subjects 1-20 years of age, females were 60% more likely to die than males (relative risk = 1.6, 95% confidence interval 1.4-1.8). Outside this age range, male and female survival rates were not significantly different. The median survival for females was 25.3 years and for males was 28.4 years. Nutritional status, pulmonary function, and airway microbiology at a given age were strong predictors of mortality at subsequent ages. Nonetheless, differences between the genders in these parameters, as well as pancreatic insufficiency, age at diagnosis, mode of presentation, and race, could not account for the poorer survival among females. Even after adjustment for all these potential risk factors, females in the age range 1-20 years remained at greater risk for death (relative risk = 1.6, 95% confidence interval 1.2-2.1). The authors concluded that in 1- to 20-year-old individuals with cystic fibrosis, survival in females was poorer than in males. This "gender gap" was not explained by a wide variety of potential risk factors.

Adolescent↗
PubMed1997

Familial and personal medical history of cancer and nervous system conditions among adults with glioma and controls.

The causes of glioma, the most common type of primary malignant brain tumor, are poorly understood. This study compared the personal and first-degree familial medical histories of 462 adults newly diagnosed with glioma in the San Francisco Bay Area between August 1, 1991, and March 31, 1994, with those of 443 controls who were frequency-matched on age, sex, and ethnicity. Cases and controls had equivalent personal histories of cancers other than brain cancer and most nervous system conditions, but they differed significantly regarding histories of epilepsy, seizures, or convulsions 3 or more years prior to diagnosis (odds ratio = 3.3, 95% confidence interval (CI) 1.4-7.9), chickenpox (odds ratio = 0.4, 95% CI 0.3-0.6), and shingles (odds ratio = 0.5, 95% CI 0.3-0.8). Four cases (less than 1%) and no controls had known genetic disorders (three had neurofibromatosis and one had tuberous sclerosis). Cases and controls had similar family histories of cancer and seizures. However, the odds ratio for a validated family history of primary brain tumor was 2.3 (95% CI 1.0-5.8). These results suggest that although family history of any cancer probably is not an important risk factor for adult glioma, a family history of brain tumors may play a role. Variation in exposure to or biologic response to common viral infections might play a greater role in the etiology of adult glioma than family history.

Adult↗
PubMed1997

A metalloproteinase disintegrin that releases tumour-necrosis factor-alpha from cells.

Mammalian cells proteolytically release (shed) the extracellular domains of many cell-surface proteins. Modification of the cell surface in this way can alter the cell's responsiveness to its environment and release potent soluble regulatory factors. The release of soluble tumour-necrosis factor-alpha (TNF-alpha) from its membrane-bound precursor is one of the most intensively studied shedding events because this inflammatory cytokine is so physiologically important. The inhibition of TNF-alpha release (and many other shedding phenomena) by hydroxamic acid-based inhibitors indicates that one or more metalloproteinases is involved. We have now purified and cloned a metalloproteinase that specifically cleaves precursor TNF-alpha. Inactivation of the gene in mouse cells caused a marked decrease in soluble TNF-alpha production. This enzyme (called the TNF-alpha-converting enzyme, or TACE) is a new member of the family of mammalian adamalysins (or ADAMs), for which no physiological catalytic function has previously been identified. Our results should facilitate the development of therapeutically useful inhibitors of TNF-alpha release, and they indicate that an important function of adamalysins may be to shed cell-surface proteins.

ADAM Proteins↗
PubMed1997

Evidence for a role of Rho-like GTPases and stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) in transforming growth factor beta-mediated signaling.

Transforming growth factor beta (TGF-beta) is a multifunctional factor that induces a wide variety of cellular processes which affect growth and differentiation. TGF-beta exerts its effects through a heteromeric complex between two transmembrane serine/threonine kinase receptors, the type I and type II receptors. However, the intracellular signaling pathways through which TGF-beta receptors act to generate cellular responses remain largely undefined. Here, we report that TGF-beta initiates a signaling cascade leading to stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) activation. Expression of dominant-interfering forms of various components of the SAPK/JNK signaling pathways including Rho-like GTPases, mitogen-activated protein kinase (MAPK) kinase kinase 1 (MEKK1), MAPK kinase 4 (MKK4), SAPK/JNK, and c-Jun abolishes TGF-beta-mediated signaling. Therefore, the SAPK/JNK activation contributes to TGF-beta signaling.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1997

Long-term survival of elderly trauma patients.

OBJECTIVE: To evaluate the long-term survival and factors that influence survival among a cohort of elderly trauma patients compared with an uninjured cohort. DESIGN: A retrospective cohort analysis. DATA SOURCES: Health Care Finance Administration, Baltimore, Md, Medicare data. SUBJECTS: A cohort of elderly patients (n = 9424) hospitalized for injury in 1987 was identified using Medicare hospital discharge abstract data. An uninjured comparison group (n = 37,787) was identified from Medicare eligibility files. For injured patients, an Injury Severity Score was generated from the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9CM) codes. For both cohorts, preexisting illness was assessed by ICD-9CM codes from Health Care Finance Administration outpatient and inpatient data files for 1986 and 1987. MAIN OUTCOME MEASURES: Relative risk for mortality within 5 years subsequent to injury, adjusted for age, sex, and preexisting illness, using Cox proportional hazard regression. RESULTS: The injured cohort had a significantly reduced 5-year survival when compared with the uninjured group (relative risk [RR] = 1.71; 95% confidence interval, 1.66-1.77). The lower survival persisted even among patients who survived at least 3 years after injury. Coexisting disease, age, and Injury Severity Score were strong predictors of survival. CONCLUSIONS: The adverse effect of trauma on survival in elderly patients is not isolated to the immediate postinjury period, but lasts years after the trauma episode. Further study is required to identify the reasons for this persistent effect of trauma on subsequent survival.

Aged↗
PubMed1997

Group psychoeducation for bulimia nervosa with and without additional psychotherapy process sessions.

OBJECTIVE: The present study examined whether additional sessions of group psychotherapy process (PP) would incrementally benefit bulimia nervosa (BN) subjects over and above that which is achieved through a course of brief group psychoeducation (PE). METHOD: Utilizing a quasi-experimental design, the first cohort of 40 BN subjects completed five-session PE-alone groups that were highly didactic and explicitly devoid of group process work. The second cohort of 41 BN subjects completed 12-session PE + PP groups that integrated PE with more conventional cognitive-behavioral group process interventions. RESULTS: Both treatments were associated with comparable levels of change on measures of specific and nonspecific psychopathology. Furthermore, the two treatments did not differ in rates of premature termination, in rates of remission in eating symptoms, in rates of normalization of scores on psychometric measures, or in consumer evaluation of the treatments. DISCUSSION: While subjects value the opportunity to engage in psychotherapy process with other group members, the addition of seven such sessions offers no enhanced therapeutic benefit over five sessions of group PE.

Adolescent↗
PubMed1997

A randomized controlled trial of fluoxetine and cognitive behavioral therapy for bulimia nervosa: short-term outcome.

This study compared and combined fluoxetine and individual cognitive behavioral therapy in the treatment of bulimia nervosa. Participants were 76 women who sought treatment at the Eating Disorders Program of the Toronto Hospital and who met DSM-III-R criteria for bulimia nervosa. Subjects were randomly assigned to receive fluoxetine alone, cognitive behavior therapy alone, or the two in combination and were treated over 16 weeks. Short-term outcome revealed that all three treatment conditions were associated with clinical improvement across a wide range of parameters. The combination of pharmacotherapy and psychotherapy was superior to pharmacotherapy alone on specific parameters and there was no statistically significant advantage to the combination over psychotherapy alone. Limitations to the study include the absence of a placebo pill group and a waiting list control group as well as a substantial dropout rate across all three treatment conditions.

Adolescent↗
PubMed1997

Hans.

Explore the source record for details and available documents.

Community Health Nursing↗
PubMed1997

Risk of hospitalization because of aseptic meningitis after measles-mumps-rubella vaccination in one- to two-year-old children: an analysis of the Vaccine Safety Datalink (VSD) Project.

OBJECTIVE: To assess the level of increased risk, if any, of hospitalizations for aseptic meningitis after Jeryl-Lynn mumps strain measles-mumps-rubella (MMR) vaccine in the Vaccine Safety Datalink population. STUDY DESIGN: A possible increased risk of aseptic meningitis 8 to 14 days after receipt of MMR was observed in a preliminary screening analysis of automated data from the Vaccine Safety Datalink (VSD) project Year 2 analysis. To further evaluate this association a retrospective 10-year matched case-control study was undertaken in the four health maintenance organizations (HMOs) in the VSD project. Cases ascertained from a broad scan of the automated data were validated against a standard case definition. Two controls matched on age, sex, HMO and HMO membership were assigned per case. RESULTS: The VSD project involves the cooperative collection of automated vaccination and medical outcome data from four large HMOs that currently have 500,000 children younger than 7 years of age under surveillance. Review of automated screening results from the first 2 years of data revealed a possible increased risk of aseptic meningitis 0 to 14 days after MMR with a relative risk of 3.61 (95% confidence interval, 1.0 to 13.1) although the total number of cases was small. Although the automated data had suggested a possible association of aseptic meningitis with MMR containing the Jeryl-Lynn strain of mumps, review of validated hospitalized cases during the observation period did not reveal evidence of an increased risk of aseptic meningitis after MMR containing the Jeryl-Lynn strain of mumps (odds ratio < 1.0 for all analyses). CONCLUSION: Although it is recognized that hospitalized cases represent a minority of the total cases of aseptic meningitis, it is reassuring that in this evaluation no increased risk of aseptic meningitis after MMR vaccine was found.

Case-Control Studies↗
PubMed1997

Community caring: an ethnographic study within an organizational culture.

American society is demanding that health care organizations design a health care system that is more responsive to the needs of their communities. In their efforts to respond, organizations are challenged to better understand organizational dynamics, community needs, and community relationships. The purpose of this study was to explore and understand the meaning of caring for the community from the perspective of care providers in a hospital-based ambulatory program. Using a focused ethnographic design, the study was conducted in a community hospital close to a large metropolitan city. Research methods included open-ended interviews, participant observations, and examination of documents. Analysis of data revealed five major themes related to the experience of caring for the community. Themes reflected different perspectives of communities, reciprocal relationships and teams, education and prevention, shared values, and understanding community needs. At the same time, an overarching theme related to wellness, growth, and empowerment emerged. Results provided knowledge that may help increase understanding of organizational culture that impacts the development of healthy communities. Findings may also help facilitate organizational change toward the development of new models of care that are integrated with the community.

Anthropology, Cultural↗
PubMed1997

Development of an antimicrobial susceptibility surveillance system for Neisseria gonorrhoeae in Malawi: comparison of methods.

Susceptibility of Neisseria gonorrhoeae to gentamicin, the primary treatment for gonorrhea in Malawi since 1993, was determined by using agar dilution MICs, E-test MICs, disc diffusion, and clinical cure rate. Agar dilution MICs were slightly higher in 1996 than in 1993 isolates, with a concomitant drop in the clinical cure rate. E-test MICs were substantially lower than agar dilution determinations, with only 77.4% within 1 log2 concentration.

Anti-Bacterial Agents↗
PubMed1997

N-acetyl cysteine ameliorates ischemic renal failure.

Recovery from ischemic renal injury is accompanied by enhanced DNA synthesis and a typical immediate early (IE) gene response. These two processes occur in distinct cell populations, suggesting that the IE gene response does not serve a proliferative function directly. As cellular stress induces an IE response through activation of the stress-activated protein kinases (SAPK) that is not proliferative and can be inhibited by N-acetyl-L-cysteine (NAC), we determined whether the Jun NH2-terminal kinases (JNK), members of the SAPKs, are activated during ischemia and whether NAC administration reduces the IE response and/or the induction of JNK activity. NAC (6 mM/kg body wt) infused 1 h prior to and 1 h following renal ischemia reduced c-fos and c-jun expression by 50 and 70%, respectively. Ischemia increased JNK activity, and this increase was inhibited by NAC. NAC infused animals had a higher glomerular filtration rate at 1 day (NAC, 0.9 +/- 0.2, vs. control, 0.05 +/- 0.01 ml/min, P < 0.001) and 7 days (NAC, 2.0 +/- 0.1, vs. control, 1.2 +/- 0.1, P < 0.001) after the induction of ischemia. NAC did not reduce the extent of proximal tubule necrosis at 24 h after reperfusion but improved histological appearance of the kidney at 7 days. The mechanism by which NAC ameliorates the loss of renal function is unknown but may involve its general properties as an antioxidant or a possible interaction with NAC and NO. We conclude that the IE gene response of the kidney to ischemia reperfusion is a consequence of the stress-activated kinase pathway and that part of the response is deleterious to kidney function and cellular integrity.

Acetylcysteine↗
PubMed1997

Paraplegia: prolonged closed-loop standing with implanted nucleus FES-22 stimulator and Andrews' foot-ankle orthosis.

Our object is to develop a reliable, implantable and closed-loop functional electrical stimulator (FES) hybrid system for safe prolonged standing in paraplegic individuals. Open-loop FES systems rapidly induce muscle fatigue that limits paraplegic standing to less than 20 and typically 10 min. Since December 1991, a paraplegic male (CS: 23 years old, T10 level, Asia: A) has been implanted with the first Nucleus FES-22 channel stimulating system (Cochlear Ltd., Lane Cove, N.S.W., Australia). Epineural platinum disc electrodes (2.5 mm) were placed on branches of the femoral, gluteal and sciatic nerves, which can be activated to produce controlled lower extremity movements for exercise and standing. No medical complications have occurred during these 5 1/2 years of implantation. The ankles are stabilized with Andrews' ankle-foot braces, the knees are free to flex. With bilateral knee goniometers fitted to sense a 10 degrees angle flexion, this hybrid closed-loop stimulation system allows the patient to achieve safe uninterrupted standing for over 60 min. The stimulator has needed to be activated 'on' for 8% (range: 3-17%) of the standing times, preventing muscle fatigue, with little or no changes found in the vital signs. The patient can manipulate and transfer objects at arm length up to 2.2 kg with good stability. New, less obstrusive sensors are currently being tested for a safer and more reliable closed-loop system.

Adult↗
PubMed1997

Nadroparin calcium. A review of its pharmacology and clinical use in the prevention and treatment of thromboembolic disorders.

Nadroparin (nadroparin calcium) is a low molecular weight heparin with a mean molecular weight of 4.5 kD. Compared with unfractionated heparin (UFH), nadroparin has a greater ratio of anti-factor Xa to anti-factor Ha activity, greater bioavailability and a longer duration of action, allowing it to be administered by subcutaneous injection for prophylaxis or treatment of thromboembolic disorders. In clinical trials conducted in older patients (mean age usually > 60 years), nadroparin was at least as effective as UFH in preventing deep vein thrombosis (DVT) and pulmonary embolism after major general or orthopaedic surgery, and in bedridden medical patients. Nadroparin was also at least as effective as dalteparin or oral acenocoumarol in preventing thromboembolic events following general and orthopaedic surgery, respectively. When used for treatment of established DVT, nadroparin was at least as effective as intravenous UFH. Subcutaneous nadroparin, at dosages similar to those used for the treatment of DVT, produced promising results in older patients with pulmonary embolism, acute ischaemic stroke or unstable angina. In 1 study, 75% of nadroparin-treated patients were able to complete their treatment at home and 36% did not require admission to hospital; the potential pharmacoeconomic implications of these results deserve further evaluation. Overall treatment costs (drug acquisition and monitoring costs) were similar for nadroparin and UFH in a French study, but nadroparin was associated with significantly less nursing time spent on treatment delivery. Nadroparin is well tolerated by older patients. The most frequently reported adverse events in a large (n approximately 4500) placebo-controlled study in general surgical patients were wound and injection site haematoma (11.8 and 10.2%, respectively, vs approximately 6.5% for placebo). When used as prophylaxis, no significant differences in bleeding complications were noted between nadroparin and UFH or acenocoumarol recipients. Prophylactic nadroparin was associated with significantly fewer withdrawals because of adverse events than UFH in elderly bedridden medical patients. When used as treatment for DVT, nadroparin was generally associated with lower occurrences of major bleeding than intravenous UFH (0.5 to 2.3% vs 2 to 5%); however, trials were not large enough to demonstrate any significant differences between the 2 agents. Similarly, the incidence of thrombocytopenia was slightly, but generally not significantly, lower in nadroparin (< 1%) than in UFH (< or = 3.5%) recipients. Thus, nadroparin should be considered an effective and well tolerated alternative to UFH for prophylaxis and treatment of DVT in older patients, with the advantage of more convenient administration and decreased monitoring requirements.

Absorption↗
PubMed1997

Nefazodone. A review of its pharmacology and clinical efficacy in the management of major depression.

Nefazodone hydrochloride is a phenylpiperazine antidepressant with a mechanism of action that is distinct from those of other currently available drugs. It potently and selectively blocks postsynaptic serotonin (5-hydroxytryptamine; 5-HT) 5-HT2A receptors and moderately inhibits serotonin and noradrenaline (norepinephrine) reuptake. In short term clinical trials of 6 or 8 weeks' duration, nefazodone produced clinical improvements that were significantly greater than those with placebo and similar to those achieved with imipramine, and the selective serotonin reuptake inhibitors (SSRIs) fluoxetine, paroxetine and sertraline. The optimum therapeutic dosage of nefazodone appears to be between 300 and 600 mg/day. Limited long term data suggest that nefazodone is effective in preventing relapse of depression in patients treated for up to 1 year. Analyses of pooled clinical trial results indicate that nefazodone and imipramine produces similar and significant improvements on anxiety- and agitation-related rating scales compared with placebo in patients with major depression. Short term tolerability data indicate that nefazodone has a lower incidence of adverse anticholinergic, antihistaminergic and adrenergic effects than imipramine. Compared with SSRIs, nefazodone causes fewer activating symptoms, adverse gastrointestinal effects (nausea, diarrhoea, anorexia) and adverse effects on sexual function, but is associated with more dizziness, dry mouth, constipation, visual disturbances and confusion. Available data also suggest that nefazodone is not associated with abnormal weight gain, seizures, priapism or significant sleep disruption, and appears to be relatively safe in overdosage. Nefazodone inhibits the cytochrome P450 3A4 isoenzyme and thus has the potential to interact with a number of drugs. Further long term and comparative studies will provide a more accurate assessment of the relative place of nefazodone in the management of major depression. Nonetheless, available data suggest that nefazodone is a worthwhile treatment alternative to tricyclic antidepressants and SSRIs in patients with major depression.

Animals↗
PubMed1997

Fosinopril. A review of its pharmacology and clinical efficacy in the management of heart failure.

Fosinopril is the prodrug of the active diacid ACE inhibitor fosinoprilat. In patients with heart failure, fosinopril reduces pulmonary capillary wedge pressure, mean arterial blood pressure, mean right atrial pressure and heart rate, and increases stroke volume index and cardiac index. The drug has compensatory dual elimination routes via renal and hepatic systems and accumulates to a lesser extent than enalapril and lisinopril in patients with chronic renal insufficiency with or without heart failure. Comparative studies of 3 or 6 months' duration with fosinopril 10 to 40 mg/day have demonstrated clinical efficacy significantly superior to that of placebo in patients with heart failure [mostly New York Heart Association (NYHA) functional class II or III]. Fosinopril treatment consistently increased exercise duration and improved heart failure symptoms in these patients. Significantly fewer fosinopril than placebo recipients withdrew or were hospitalised because of worsening heart failure. Additionally, significantly more fosinopril than placebo recipients showed improvement, and fewer patients had deteriorated, in terms of NYHA functional class. Fosinopril and enalapril showed similar clinical efficacy over 6 and 12 months' treatment in patients with NYHA functional class II to IV heart failure. As yet, there are no data showing a mortality benefit with fosinopril. Fosinopril was well tolerated in clinical trials in patients with heart failure. Dizziness (11.9 vs 5.4% for placebo), cough (9.7 vs 5.1%) and hypotension (4.4 vs 0.8%) were the most commonly reported adverse events. In 6- or 12-month comparative studies, fosinopril therapy was associated with a lower incidence of dizziness and hypotension, but a higher incidence of vertigo, than enalapril therapy. 0.8% of patients discontinued the drug because of cough, which occurred to a similar extent with fosinopril and enalapril. Thus, based on available clinical evidence, fosinopril is an effective and well tolerated option for the management of patients with heart failure. Although clinical data are limited, fosinopril may be especially useful in patients with renal or hepatic impairment.

Angiotensin-Converting Enzyme Inhibitors↗