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Biomedical subjects

K M Davis

Publications and source records attributed to K M Davis.

15 recordsLinked to original sources
PubMed1992

Atrial natriuretic peptide levels in the prediction of congestive heart failure risk in frail elderly.

OBJECTIVE: To develop a noninvasive clinical predictive model for acute congestive heart failure (CHF) in a frail elderly cohort using bedside clinical assessment (medical history and physical examination) and venous atrial natriuretic peptide (ANP) levels. DESIGN: One-year prospective blinded cohort study. SETTING: Life care facility. PARTICIPANTS: Three hundred thirty-one frail, elderly volunteers free of acute illness at study entry (mean +/- SD age, 88 +/- 7 years; 23% male, 77% female). MAIN OUTCOME MEASURE: Clinical episodes of CHF with confirmation of acute pulmonary edema by chest roentgenogram. RESULTS: Fifteen percent of the elderly cohort developed at least one episode of CHF during the 1-year follow-up period. Those developing CHF had significantly higher mean +/- SE ANP values at study entry: 493 +/- 55 vs 207 +/- 15 pmol/L. The risk for development of CHF rose progressively with increasing ANP levels at study entry. In multivariate analysis, only two independent variables significantly predicted CHF: ANP value greater than 200 pmol/L (adjusted odds ratio [OR], 7.9; 95% confidence interval [CI], 3.2 to 19.2) and history of CHF in the previous year (adjusted OR, 7.0; 95% CI, 2.9 to 17). Stratifying the cohort by these two variables results in three CHF risk groups: 55% of the population at 3% annual risk of CHF, 37% of the population at 20% to 24% annual risk of CHF, and 8% of the population at 66% annual risk of CHF. CONCLUSIONS: This simple clinical prediction model identifies elderly subjects at risk for CHF and allows appropriate focusing of medical resources for prevention, early detection, and treatment of this highly morbid clinical syndrome.

Acute Disease↗
PubMed1992

Autonomic surface potential analysis: assessment of reproducibility and sensitivity.

There has been recent interest in measuring sympathetic sudomotor function by autonomic surface potential analysis. The purpose of the present study was to assess factors affecting the reproducibility of the test. We determined the within-day and between-day reproducibility in 24 healthy volunteers. We used an increasing rather than a constant electrical stimulus to minimize habituation. The amplitudes were still highly variable (an average within-day coefficient of variation in the soles of 35%). Habituation did not, however, affect the latencies of the responses, which were much more reproducible (an average within-day coefficient of variation in the soles of 8%). Studies of between-day reproducibility revealed that the mean amplitudes were lower on day 2 vs. day 1 (0.706 +/- 0.10 vs. 0.85 +/- 0.10 mV in the soles, P less than 0.01) but the mean latencies were similar on the different testing days (2.09 +/- .04 seconds for the soles on day 1 vs. 2.16 +/- .05 seconds on day 2). We also assessed the sensitivity of surface potential analysis and report the results of testing 35 patients with far advanced autonomic neuropathy.

Aged↗
PubMed1992

Endometriosis.

Recent advances in endometriosis research are reviewed. Factors relating to the increasing frequency of laparoscopic diagnosis as well as potential diagnostic tests utilizing endometrial antibody and CA 125 assays of both serum and peritoneal fluids are discussed. A new classification is proposed that takes into consideration depth of endometriotic lesions. The pathophysiology of endometriosis is an area of increased research activity with attention directed toward autoimmune theories of impaired surveillance. A variety of autoantibodies have been found to be increased in patients with endometriosis, and peritoneal macrophage activation is also thought to play a role. Laparoscopic treatment options are reviewed, including investigations of various laser methods as well as electrocautery. Medical therapy comparing various gonadotropin-releasing hormone agonists and danazol and the effects of these treatment options on bone density are presented. New directions in immunomodulatory drug therapy are discussed.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1991

Hemodynamic effects of octreotide in patients with autonomic neuropathy.

BACKGROUND: The somatostatin analogue, ectrootide, is being used to treat postprandial hypotension in patients with autonomic neuropathy. Although the therapeutic effect of the drug is presumably secondary to a splanchnic vasoconstrictor action, its effect on splanchnic hemodynamics has never been characterized in patients with autonomic neuropathy. Moreover, it is unknown whether octreotide acts on other vascular beds in this group of patients or whether it affects cardiac output. We, therefore, measured splanchnic, forearm, and systemic vascular resistance and cardiac output before and after administering octreotide (0.4 microgram/kg s.c.) to patients with idiopathic autonomic neuropathy and diabetic autonomic neuropathy. METHODS AND RESULTS: Splanchnic blood flow was determined from the clearance of indocyanine green in seven patients. We observed that octreotide decreased splanchnic blood flow (from 850 +/- 77 to 664 +/- 48 ml/min, p less than 0.005), increased mean blood pressure (from 97 +/- 6 to 115 +/- 3 mm Hg, p less than 0.005), and increased splanchnic vascular resistance (from 0.118 +/- 0.012 to 0.18 +/- 0.018 mm Hg/ml/min, p less than 0.005). Forearm blood flow was measured by plethysmography in 13 patients. Octreotide increased forearm vascular resistance in patients with idiopathic autonomic neuropathy (n = 8) from 19.1 +/- 1.0 to 27.2 +/- 3.8 mm Hg/ml/min/100 ml forearm volume (p less than 0.01) and from 25.2 +/- 3.9 to 41.0 +/- 6.8 mm Hg/ml/min/100 ml (p less than 0.01) in patients with diabetic autonomic neuropathy (n = 5). Cardiac output was measured by two-dimensional echocardiography. Octreotide administration increased cardiac output in five of six patients with idiopathic autonomic neuropathy (from 4.4 +/- 0.4 to 5.0 +/- 0.5 l/min, p less than 0.02) and five of five patients with diabetic autonomic neuropathy (from 3.8 +/- 0.4 to 5.1 +/- 0.4 l/min, p less than 0.02). Systemic vascular resistance increased in patients with idiopathic autonomic neuropathy from 21.2 +/- 2 to 24.9 +/- 2.6 (p less than 0.05) but did not change in patients with diabetic autonomic neuropathy. CONCLUSION: The pressor effect of octreotide in patients with autonomic neuropathy is associated with increased splanchnic and forearm vascular resistance and with increased cardiac output.

Adolescent↗
PubMed1991

The orthostatic tachycardia syndrome: evaluation of autonomic function and treatment with octreotide and ergot alkaloids.

Orthostatic tachycardia is a poorly understood syndrome in which patients develop dizziness, diaphoresis, or palpitations upon shifting from the supine to the upright posture. The present study was performed to determine whether autonomic neuropathy might be present in these patients, and whether the abnormal hemodynamic response to standing might be the result of failure of reflex vasoconstriction. We measured autonomic function in 9 patients with idiopathic orthostatic tachycardia and 2 patients with orthostatic tachycardia and insulin-dependent diabetes mellitus and compared them to 33 age-matched controls. Although most patients with orthostatic tachycardia had normal vasomotor reflexes and normal surface potential amplitudes, the latency of the autonomic response, a measure of sympathetic nerve conduction velocity, was prolonged in the soles (2.44 +/- 0.08 s in patients with idiopathic orthostatic tachycardia vs. 2.12 +/- 0.04 s in controls; P less than 0.005). In 6 of 9 patients, however, the latencies were within the normal range. Autonomic surface potentials were absent in 1 diabetic patient with orthostatic tachycardia; the latency of the response in the feet was greatly prolonged (2.95 s) in the second patient. We also assessed the response of orthostatic tachycardia patients to octreotide and dihydroergotamine, which are known to have a pressor effect in patients with recognized forms of autonomic neuropathy. These agents, in combination, suppressed orthostatic tachycardia (from 116 +/- 7 to 89 +/- 6 beats/min; P less than 0.001) in patients with this syndrome. In summary, our data indicate that evidence of autonomic dysfunction is present in only a minority of patients with orthostatic tachycardia. Nevertheless, administration of the vasoconstrictor drugs dihydroergotamine and octreotide can prevent the abnormal hemodynamic response to the upright posture shown by patients with this syndrome.

Adult↗
PubMed1989

Geriatric depression: physicians' knowledge, perceptions, and diagnostic practices.

An evaluation of physicians' (medical residents) knowledge revealed that whereas they considered detection and treatment of comorbid depression to be important, they knew few of the diagnostic criteria and etiological factors, rarely screened their patients for depression, and viewed current treatments as only marginally efficacious. Implications for graduate training are discussed.

Adult↗
PubMed1988

Systemic treatment of cancer in the elderly.

The goal of this review is to provide a readable and exhaustive reference in three major areas of geriatric oncology: complications of chemotherapy and radiotherapy, responsiveness of cancer to systemic treatment, social issues in the care of elderly patients with terminal illnesses. The conclusions of this study are: 1. Progressive deterioration of renal function is the most consistent change of aging. Adjustment of doses of renally excreted drugs to individual creatinine clearance may prevent life-threatening myelotoxicity in the elderly. 2. Intensive chemotherapy regimens (acute leukemia, non Hodgkin's lymphoma) cause more serious and prolonged myelotoxicity in the elderly. Elderly are more susceptible than younger patients to cardiotoxicity and central and peripheral neurotoxicity. Age is a poor predictor of complications in other organs or systems. 3. The prognosis of patients with Hodgkin's disease worsens with aging, possibly due to increased prevalence of mixed cellularity histology. It is controversial whether the prognosis of other neoplasias is poorer. Prognosis is not age-related in multiple myeloma. In general, elderly in good performance status may benefit from systemic cancer treatment to the same extent as younger patients, except for Hodgkin's disease. 4. The Informal Support Network, epitomized by the family, appears the most suitable environment to care for the elderly with cancer.

Aged↗
PubMed1987

Physician awareness of cost under prospective reimbursement systems.

The failure of some strategies to reduce physician use of costly hospital services has been attributed in part to retrospective reimbursement systems. However, anticipation of changes in the reimbursement structure has led to speculation that a different environment might lead to increased cost awareness by physicians. To measure the impact of prospective reimbursement systems on physician awareness of cost, the authors surveyed 46 medicine residents and faculty at a medical center. Data show that only 34% were able to correctly estimate common charges and 24% less common charges. In the early stages of prospective reimbursement, there has been no increased physician awareness of cost.

Cost Control↗
PubMed1987

Brain death: nursing roles and responsibilities.

Nurses working in an intensive care setting must be knowledgeable about the diagnosis of brain death and its ramifications to care competently for the patient and family. The medical community has identified specific physical and diagnostic findings necessary for the determination of brain death. Brain death is an irreversible state, from which recovery has never been reported. The neuroscience nurse's responsibilities include meeting the patient's physical needs and identifying the family's needs and teaching them about brain death. Not fulfilling these responsibilities could result in dysfunctional grieving for the family and loss of a potential organ donor.

Brain Death↗
PubMed1985

Anaplastic neoplasm in a patient with hairy cell leukemia.

A 63-year-old white man had a history of recurrent pneumonia, pancytopenia, and splenomegaly when the diagnosis of hairy cell leukemia was made on bone marrow biopsy examination. Splenectomy confirmed that diagnosis and his pancytopenia moderately improved. Three years following the diagnosis, the patient developed an upper abdominal mass involving the stomach wall that was found to be an anaplastic "large cell" neoplasm. Palliative radiotherapy was started, but the patient died 2 months later. Cytochemical studies of the anaplastic gastric neoplasm revealed cytoplasmic tartrate resistant acid phosphatase activity. Electron microscopy showed no epithelial differentiation. These observations suggest that the gastric neoplasm represented an evolution of hairy cell leukemia into a more aggressive tumor analogous to the transformation that occurs in other B-cell neoplasms.

Bone Marrow↗
PubMedDate not supplied

Listeria rhombencephalitis mimicking tuberculous meningitis.

A previously healthy man developed a progressive neurologic illness characterized by an "aseptic meningitis syndrome," progressive hypoglycorrhachia, and severe brain-stem dysfunction. Initial dramatic response to antituberculosis therapy supported the diagnosis of tuberculous basilar meningitis; however, Listeria monocytogenes eventually grew in a blood culture, and the patient recovered following intravenous ampicillin therapy. The entity of listerial rhombencephalitis should be considered as a treatable cause of acute, progressive brain-stem meningoencephalitis.

Acute Disease↗
PubMedDate not supplied

Magnetic resonance imaging in congenital dysplasia of the hip.

This study was designed to determine the usefulness of magnetic resonance imaging (MRI) in managing congenital hip dysplasia and dislocation. We compared various hip parameters using bony and cartilaginous landmarks. MRI determined that the bony acetabular index (AI) accurately reflects the cartilaginous AI. Bony acetabular indices greater than 30 degrees indicated hip dysplasia, subluxation, or dislocation. MRI demonstrates qualitative information not available on plain films; however, it does not provide further quantitative data, so we do not recommend its routine use in the evaluation of congenital hip dysplasia. The true benefit of MRI may be its ability to identify a group of patients with bone dysplasia but normal cartilaginous growth potential.

Child↗