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Biomedical subjects

J W Davis

Publications and source records attributed to J W Davis.

At least 19 recordsLinked to original sources
PubMed1996

Postdischarge geriatric assessment of hospitalized frail elderly patients.

BACKGROUND: The diffusion of comprehensive geriatric assessment services has been rather limited in North America partly because of reimbursement and organizational constraints. OBJECTIVE: To evaluate the impact of a comprehensive geriatric assessment intervention for frail older patients that is started before hospital discharge and is continued at home. METHODS: Patients older than 65 years were selected who had either unstable medical problems, recent functional limitations, or potentially reversible geriatric clinical problems. Patients (n = 354) were randomly assigned to either the intervention group or a control group. Information on survival, readmissions, nursing home placement, medication use, and health status was collected at 30 and 60 days after hospital discharge. RESULTS: No differences were observed between the two treatment groups in survival, hospital readmission, or nursing home placement by 60 days. After adjustment for baseline characteristics, no significant differences were observed between the two groups on measures of physical functioning, social functioning, role limitations, health perceptions, pain, mental health, energy and/or fatigue, health change, or overall well-being. CONCLUSIONS: Although efficacy has been demonstrated for some forms of comprehensive geriatric assessment, the types of services that are easier to establish (inpatient consultation services and ambulatory assessment) have not been shown to improve outcomes. Our results indicate that outcomes are unaffected by a limited form of comprehensive geriatric assessment begun in the hospital and completed at home. Further efforts are needed to develop and to evaluate realistic approaches to comprehensive geriatric assessment.

Aged↗
PubMed1995

High-risk behavior and the public burden for funding the costs of acute injury.

OBJECTIVE: To determine if high-risk behavior is associated with increased injury severity and cost and if public agencies bear a disproportionate burden of that cost. DESIGN: Case comparison study utilizing patient data collected over a 10-year period. SETTING: Five level 1 and 2 trauma centers in an urban-suburban community with a population of 2.4 million. PARTICIPANTS: Trauma registry data from 37,304 consecutive hospitalized adult patients with trauma. Financial data were reported and analyzed on 28,842 of these. MAIN OUTCOME MEASURES: Incidence of alcohol intoxication, other drug use, use of vehicular protective devices, and firearm violence injuries in patients with private vs public health care sponsorship. Length of hospital stay, injury severity, and hospital unit charges were assessed for high-risk behavior. RESULTS: High-risk behavior was more prevalent among trauma patients relying on public funding to cover the costs of their injuries (P < .001). Total hospital unit charges were 28% and 35% higher for motorists not wearing seat belts and motorcyclists not wearing helmets, respectively. Injury severity and length of stay were also higher (P < .001). CONCLUSIONS: High-risk behavior is associated with increased injury severity and cost. Trauma victims exhibiting high-risk behavior more often depend on public agencies to cover the cost of acute injury. Failure to establish and enforce laws and policies designed to reduce or prevent injury may generate enormous trauma care costs, borne to a large extent by public agencies. Further restriction of certain types of high-risk behavior and the institution of "users' fees," taxes, or penalties may be necessary to reduce the disproportionate public agency cost generated by this activity.

Acute Disease↗
PubMed1995

A longitudinal study of estrogen and calcium supplement use among Japanese women living in Hawaii.

BACKGROUND: Estrogen and calcium supplements represent accepted treatments for the prevention of osteoporosis in the United States. The effectiveness of these treatments, however, will depend upon the extent that they are utilized, which may vary over time. METHODS: We report a longitudinal study of estrogen and calcium use among a cohort of Japanese-American women living in Hawaii. Their mean age at the baseline examination in 1981 was 63.9 (age range 45 to 81). Between 1981 and 1992 the same women were repeatedly surveyed regarding their estrogen and calcium supplement use. RESULTS: During the decade of follow-up the prevalence of estrogen use doubled, with 25 to 30% of the women reporting estrogen use in the later years. The prevalence of calcium supplement use (500 mg/day or more) quadrupled over the same interval, with 20% of the women reporting calcium supplement use in the later years. The increases in estrogen and calcium supplement use derived from complex patterns of use. For estrogen, less than half of the users in 1981 were still using 5 years later; the number of women stopping estrogen, however, were more than replaced by new estrogen users. For calcium supplements, fewer than half of the women initiating use continued for as long as 5 years. Women beginning estrogen were younger, had more often used estrogen in the past, had a lower body mass index, had dietary calcium intakes of 400 mg/day or greater, and were more likely to have regularly used alcohol. Women initiating calcium supplements exhibited several of the same characteristics as women initiating estrogen use (younger age, past estrogen use, and regular alcohol use). CONCLUSIONS: The changes in use over the past decade may reduce the risk of osteoporotic fractures among our cohort. Benefits from the changes, however, could be limited by the inconsistent use by many of the cohort women. Also of concern are the weak associations observed between estrogen and calcium supplement use and bone mass measurements, which are strong indicators of fracture risk. It appears that treatment in our cohort has failed to reach many of the women with the greatest fracture risks.

Age Factors↗
PubMed1995

Users of low-dose glucocorticoids have increased bone loss rates: a longitudinal study.

Although high doses of glucocorticoids are believed to cause bone loss, the effects of low glucocorticoid doses are still controversial. Our study examined the effects of low-dose glucocorticoids on the rate of bone loss at three appendicular bone sites. The study population was a cohort of elderly Japanese-Americans, 1094 women and 1378 men. The women were all postmenopausal. At the baseline examination the mean age of the women was 64 years (range 45-81), and the mean age of the men was 68 years (range 61-82). Glucocorticoid users (19 women and 21 men) had used oral systemic or inhaled glucocorticoids on a regular schedule for more than 1 month (mean use was 2.1 years for the women and 1.9 years for the men). The most common dose was equivalent to 5 mg/day of prednisone; fewer than 15% of users had taken doses equivalent to 10 mg/day or more. Changes in bone mass at the calcaneus, distal radius, and proximal radius were documented using bone densitometry at 1 to 2-year intervals over an 8-year period. The initial bone mass of the glucocorticoid users and controls was similar at the baseline examination. The subsequent loss rates among females during glucocorticoid use, however, were approximately double that of the controls. Among males, bone loss rates during glucocorticoid use were 2-3 times that of controls for the calcaneus and radius sites. The differences between glucocorticoid users and controls persisted after adjusting for confounding variables such as age and use of thiazides and estrogens.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Relation of height and weight to the regional variations in bone mass among Japanese-American men and women.

We examined the magnitude of regional variations in bone mass among elderly, Japanese-American men and women. All subjects had bone measurements at the calcaneus, and at the distal and proximal radius sites. A subset of the women had, in addition, spine bone mass measurements. To provide a common measurement scale, the bone measurements were converted to age- and sex-specific Z-scores. The Z-scores between pairs of bone sites were then subtracted to yield the differences in bone mass between bone sites (expressed in Z-score units). For most individuals the differences were less than 1.0 Z-score; however, 12%-20% of the differences were at least 1 Z-score apart. The most similar sites were the distal and proximal radius: different regions within the same bone. Among the other bone pairs, the calcaneus and spine were the most similar to one another. The magnitudes of the differences in bone mass were associated with height and weight. Heavier subjects, for instance, had greater calcaneus than radius bone mass measurements, and greater spine than radius measurements. The spine and calcaneus are more weight-bearing than the radius sites. Associations were observed up to 0.25 Z-score per 10 kg difference in weight. Height was associated with bone mass differences in an opposite direction to weight. Taller subjects had greater bone mass at the radius sites than expected from their calcaneus or spine bone measurements (0.1 to 0.2 Z-score difference per 5 cm difference in height). Bone width partly explained the associations with height; that is, adjusting the radius widths reduced the associations with height. Overall, our results indicate that small to moderate differences between bone sites were common among our study population, and that the magnitudes of the differences were associated with height and weight.

Adult↗
PubMed1995

A randomized, double-masked, placebo-controlled trial of chlorthalidone and bone loss in elderly women.

Employing a double-masked, prospective design, bone loss at three skeletal sites has been monitored among 113 postmenopausal women participating in a placebo-controlled trial of the thiazide-like diuretic chlorthalidone for treatment of systolic hypertension. The mean duration of chlorthalidone use was 2.6 years, at doses of 12.5-25 mg/day. Compared with placebo use, chlorthalidone use was associated with significant reductions in annual bone loss rates. Non-use of chlorthalidone was associated with bone loss at the calcaneus (-0.56% per year) and the proximal radius (-0.91% per year); borderline bone gain was observed at the distal radius (+0.39%). In contrast, chlorthalidone use was associated with bone gain at the calcaneus (+0.44% per year) and the distal radius (+1.51% per year); proximal radius bone loss was significantly reduced to -0.32% per year. The average increment for three appendicular sites was +0.9% per year. These data support a causal relationship between chlorthalidone use and reduced bone loss.

Aged↗
PubMed1995

Vertebral dimension measurements improve prediction of vertebral fracture incidence.

We investigated the independent contributions of vertebral size and shape, bone density, and existing fractures for predicting the risk of new vertebral fractures among postmenopausal Japanese-American women in Hawaii. Baseline measurements of bone density at the distal and proximal radius and the calcaneus were obtained in 1981, and at the lumbar spine in 1984. Incident fractures were documented on serial radiographs during an average of 8.0 years of follow up of 840 women. A positive difference of 1 standard deviation in vertebral depth increased the risk of new vertebral fractures by approximately 1.3-fold (95% confidence interval = 1.03, 1.66) after controlling for bone density and prevalent fractures. A combination of large vertebral depth (above the 66th percentile) and low bone density (below the 33rd percentile) increased fracture risk approximately six times compared to women with high bone density (above the 66th percentile) and small vertebral depth (below the 33rd percentile). We conclude that combining information about vertebral depth, bone density, and prevalent fracture appears to be better for predicting new fractures than any single variable alone.

Absorptiometry, Photon↗
PubMed1995

Estrogen and calcium supplement use among Japanese-American women: effects upon bone loss when used singly and in combination.

We examined the effects of estrogen and calcium supplementation upon bone loss among a cohort of Japanese-American women. The women averaged 64 years of age (age range 45-81) and 14 years postmenopause at their initial examination in 1981. They returned at 1-3-year intervals for subsequent examinations, most recently in 1992-1994. At each examination, bone mass was measured at the calcaneus and distal and proximal radius. The women had low average dietary calcium intakes (median intake 384 mg/day). Women taking calcium supplements reported a median supplement intake of 355 mg/day; over 75% of the women taking estrogen took the equivalent of 0.6 mg/day or more of conjugated estrogens. Women taking estrogen had uniformly slower bone loss at all three sites. Compared to women not taking estrogen, whose bone loss averaged about 1% per year, women taking estrogen had 0.75-0.85% per year decreased bone loss at the three bone sites. By contrast, women who stopped estrogen had greater than average loss rates (0.35-0.65% per year greater). Calcium supplementation also reduced bone loss, but to a lesser extent than estrogen: bone loss decreased 0.25% per year at the radius sites, but was not slowed at the calcaneus. The calcaneus is more trabecular than the radius sites, which may explain the lack of response. We also examined combined estrogen and calcium supplement use.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Portal triad injuries.

OBJECTIVE: Injuries to the portal triad are a rare and complex challenge in trauma surgery. The purpose of this review is to better characterize the incidence, lethality, and successful management schemes used to treat these injuries. DESIGN: A retrospective review of the experience of eight academic level I trauma centers over a combined 62 years. RESULTS: A retrospective review of the experience of eight anatomical structures of the portal hepatis: 118 injuries to the anatomical structures of the portal hepatis: 55 extrahepatic portal vein injuries, 28 extrahepatic arterial injuries, and 35 injuries to the extrahepatic biliary tree. Sixty-nine percent of the injuries were by penetrating mechanism and 31% were by blunt mechanism. All patients had associated injuries with a mean Injury Severity Score of 34 in blunt trauma patients. Overall mortality was 51%, rising to 80% in patients with combination injuries. Sixty-six percent of deaths occurred in the operating room, primarily from exsanguination; 18% of deaths occurred within 48 hours of injury from refractory shock, coagulopathy, or cardiac arrest; 16% occurred late. Ten percent of patients undergoing portal vein ligation survived, compared to 58% managed by primary repair. Survival after hepatic artery ligation was 42%, compared to 14% after primary repair. Survival after biliary-enteric anastomosis as treatment of extrahepatic bile duct injury was 89%, compared to 50% after primary repair and 100% after ligation of lobar bile duct injuries. Missed bile duct injuries had a high (75%) severe complication rate. CONCLUSIONS: Injuries to the anatomical structures of the portal triad are rare and often lethal. Intraoperative exsanguination is the primary cause of death, and hemorrhage control should be the first priority. Bile duct injuries should be identified by intraoperative cholangiography and repaired primarily or by enteric anastomosis; lobar bile ducts can be managed by ligation.

Adolescent↗
PubMed1995

Clearing the cervical spine in obtunded patients: the use of dynamic fluoroscopy.

OBJECTIVE: Obtunded patients (Glasgow Coma Scale score of < 13) with normal cervical roentgenograms remain in collars until they can be clinically evaluated. Cervical collars provide incomplete immobilization and have complications. Our hypothesis was that cervical spines could be evaluated in obtunded patients with normal cervical roentgenograms using dynamic fluoroscopy. DESIGN: This study was a prospective clinical evaluation. METHODS: Obtunded trauma patients with normal cervical roentgenograms underwent fluoroscopic examination of the cervical spine through a full range of motion. RESULTS: Fluoroscopic evaluations were done in 116 patients. There were 113 true negative examinations. Two patients had facet fractures not diagnosed on cervical roentgenograms, and no instability on fluoroscopy. One patient had a positive exam, with 2 mm of subluxation. There were no neurologic complications. Decubiti were present in 44% and were more frequent when the collar was on > 5 days (p = 0.029). CONCLUSIONS: Dynamic fluoroscopy can safely and effectively clear the cervical spine in obtunded patients. Earlier removal of the collar decreases decubiti.

Adult↗
PubMed1995

Iliofemoral venous injuries: an indication for prophylactic caval filter placement.

Prophylactic placement of vena caval filters is recommended in trauma patients at high risk for pulmonary embolism (PE). We present a group of patients with iliofemoral venous trauma, and subsequent complications of deep venous thrombosis (DVT) and PE. Of twelve patients with iliac or common femoral venous injuries, seven underwent primary repair. All received DVT/ PE prophylaxis with mini-dose heparin and/or sequential compression hose. In spite of this, two patients suffered DVT, one patient had DVT and PE and one patient had clinical evidence of PE but did not undergo confirmatory testing. Three patients underwent prophylactic caval filter placement without complication. The DVT/PE complication rate in this small group was at least 43% (3 of 7). Patients with repaired iliofemoral venous injuries represent a high risk subset for DVT/PE and prophylactic caval filter placement is recommended.

Adolescent↗
PubMed1995

Neurogenic pulmonary edema in fatal and nonfatal head injuries.

Impaired pulmonary function is a frequent but poorly understood complication of acute head injury (HI). A potential early contributor to the pulmonary dysfunction seen in HI patients is neurogenic pulmonary edema (NPE). We hypothesized that NPE would occur early after HI and that it would have a continuum of clinical severity depending on the severity of the HI and associated intracranial hypertension. A large autopsy data base and inpatient HI data base were used to search for cases of NPE. Patients in the autopsy data base were stratified according to injury type and whether they died at the scene or within 96 hours of injury. There were significant (p < 0.0001, analysis of variance) elevations in lung weights in patients dying at the scene and within 96 hours from HI, compared with those dying from other noncentral nervous system injuries. No other organs studied showed significant weight increases. The incidence of NPE in isolated HI patients dying at the scene was 32%. In patients with isolated HI dying within 96 hours, the incidence of NPE was 50%. We found an inverse correlation (r = 0.62; p < 0.0014) between the initial cerebral perfusion pressure and the PaO2/FIO2 ratio despite a normal-appearing chest x-ray film. We conclude that NPE occurs frequently in HI patients. The process of edema formation begins early in the clinical course and is isolated to the lung.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Mechanical determinants of myocardial oxygen consumption in conscious dogs.

A new practical descriptor of metabolic to mechanical myocardial energy transfer (MET), termed the virtual work model, was evaluated in 32 conscious dogs and in 8 isolated canine hearts. An index of total mechanical energy expenditure (TME) was calculated as the sum of external energy (stroke work) and an internal energy index of heat (left ventricular end-diastolic volume times left ventricular mean ejection pressure). Physiological comparison of TME (x-axis) and myocardial oxygen consumption (MVO2; y-axis) yielded highly linear MET relationships (mean r = 0.93 +/- 0.07), with an average slope of 0.86 +/- 0.39 (SD) and a y-intercept of 9.1 +/- 6.4 mW/ml myocardium. The linear MVO2-TME relationship did not vary under steady-state vs. dynamic vena caval occlusion, increased heart rate, increased afterload, or increased inotropic state with calcium infusion. Compared with five other indexes of myocardial energetics, the virtual work model of MET was the most linear, the most practical in not requiring determination of the end-systolic pressure-volume relationship, and the most accurate predictor of MVO2 under normal and altered hemodynamic conditions.

Animals↗
PubMed1995

Trampoline-related injuries.

Two hundred and seventeen patients who had sustained an injury during the recreational use of a trampoline were managed in the emergency room of Logan Regional Hospital in Logan, Utah, from January 1991 through December 1992. We retrospectively reviewed the charts and radiographs of these patients to categorize the injuries. Additional details regarding the injuries of seventy-two patients (33 per cent) were obtained by means of a telephone interview with use of a questionnaire. The injuries occurred from February through November, with the peak incidence in July. The patients were eighteen months to forty-five years old (average, ten years old); ninety-four patients (43 per cent) were five to nine years old. Eighty-four patients (39 per cent) sustained a fracture; fifty-four (25 per cent), a sprain or strain; forty-five (21 per cent), a laceration; and thirty-four (16 per cent), a contusion. Fifty-seven injuries (26 per cent) involved the elbow or forearm; forty-six (21 per cent), the head or neck; forty (18 per cent), the ankle or foot; thirty-three (15 per cent), the knee or leg; nineteen (9 per cent), the trunk or back; thirteen (6 per cent), the shoulder or arm; and nine (4 per cent), the wrist or hand. Thirteen patients (6 per cent) had a back injury, but none of them had a permanent neurological deficit. One patient who had an ocular injury was transferred to a tertiary care center. One hundred and fifty-six patients (72 per cent) were evaluated radiographically, fifteen (7 per cent) were admitted to the hospital, and thirteen (6 per cent) had an operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidental Falls↗
PubMed1994

Induction of hepatic acyl-CoA-binding protein and liver fatty acid-binding protein by perfluorodecanoic acid in rats. Lack of correlation with hepatic long-chain acyl-CoA levels.

Liver fatty acid-binding protein (L-FABP) and acyl-CoA-binding protein (ACBP) are involved in the intracellular trafficking and compartmentalization of fatty acids and fatty acyl-CoA esters, respectively, in the liver. Both proteins are induced in rat liver by the potent peroxisome proliferator perfluorodecanoic acid (PFDA). While it is believed that the peroxisome proliferator-activated receptor may mediate the responses to peroxisome proliferators by inducing responsive genes, the ligand(s) of this receptor remains unknown. We hypothesized that induction of L-FABP and ACBP in rat liver by PFDA is secondary to accumulation of long-chain acyl-CoA esters. However, neither dose-response nor time-course effects of PFDA on hepatic long-chain acyl-CoA, L-FABP, or ACBP concentrations confirmed this hypothesis. In a dose-response study, PFDA increased hepatic long-chain acyl-CoA concentrations (7 days after treatment) over the dose range of 20-50 mg/kg, whereas it increased ACBP and L-FABP over the wider dose range of 20-65 mg/kg. In the time-course study, PFDA treatment (50 mg/kg) elevated long-chain acyl-CoA esters in the liver beginning on day 3 post-treatment, yet hepatic L-FABP concentrations were increased earlier beginning on day 2 and ACBP was not induced until day 7. To determine if this dissociation of increases in hepatic long-chain acyl-CoA concentrations from increases in hepatic L-FABP and ACBP concentrations could be demonstrated under other conditions, control rats fasted for 24-48 hr were used. Fasting increased hepatic long-chain acyl-CoA levels to a greater extent than PFDA treatment, yet neither L-FABP nor ACBP was induced. We conclude that elevated concentrations of hepatic long-chain acyl-CoAs in PFDA-treated rats are not a major contributor to the induction of L-FABP or ACBP by peroxisome proliferators. A more plausible mechanism is that PFDA induces L-FABP and ACBP by activating the peroxisome proliferator receptor directly rather than indirectly through long-chain acyl-CoA esters.

Acyl Coenzyme A↗
PubMed1994

Evidence for both generalized and regional low bone mass among elderly women.

The consistency of bone mass measurements across bone sites was examined in a cohort of elderly Japanese-American women. The study included 744 women of mean age 66.6 years (age range 47-82 years) who had bone densitometry measurements at the spine, calcaneus, and distal and proximal radius. The women were classified at the four bone sites as in the lower, middle, or upper bone mass tertile for their age. Slightly more than half (56%) of the women were in the lower tertile at one or more of the bone sites, and such women were usually in the lower category at more than one site. Of the women, 24% were classified in the lower tertile at all four sites. Furthermore, as a group, women classified as in the low bone mass category at any one site had a low average bone mass at all four sites. Prospectively, the number of low bone mass sites predicted the risk of new spine fractures after adjusting for age and the number of spine and nonspine prevalent fractures. The risk increased approximately 1.3-fold for each additional low bone mass site. A subgroup (15%) of the population had marked heterogeneity in bone mass between sites. These women had one or more lower tertile bone mass site(s) and one or more upper tertile bone mass site(s). The results suggest that osteoporosis may occur as either a generalized or as a regional disorder.

Absorptiometry, Photon↗
PubMed1994

Inhibition of S-(1,2-dichlorovinyl)-L-cysteine-induced lipid peroxidation by antioxidants in rabbit renal cortical slices: dissociation of lipid peroxidation and toxicity.

Precision-cut, rabbit renal slices were used to examine the effects of three novel antioxidants (U-74006, U-74500, and U-78517) on S-(1,2-dichlorovinyl)-L-cysteine (DCVC)-induced lipid peroxidation and toxicity. Slices exposed to DCVC showed a dose- and time-dependent increase in lipid peroxidation (TBARS) and a decrease in cellular viability, as evidenced by the loss of intracellular potassium, during the course of a 3 hour incubation. Subsequent studies employed DCVC concentrations of 100 microM. Microemulsion formulations of U-78517, U-74500, and U-74006 (100 microM) inhibited DCVC-induced lipid peroxidation by 100 +/-, 50 +/-, and < 5% (not significant), respectively. However, none of these antioxidants had a significant effect on DCVC-dependent cytotoxicity, as indicated by intracellular potassium release. The effects of U-78517, the most potent of the three antioxidants, were similar to those observed with two model antioxidants, diphenyl-p-phenylenediamine (DPPD) and the iron chelator, deferoxamine. Aminooxyacetic (AOAA), an inhibitor of renal cysteine conjugate beta-lyase, had only a minimal effect on DCVC-induced lipid peroxidation, and no effect on toxicity. These data represent the first report of DCVC-induced lipid peroxidation in rabbit renal cortical slices, a system which has been widely used to investigate mechanisms of nephrotoxicity, including that induced by DCVC. Our results demonstrate that DCVC-induced lipid peroxidation in renal slices can be inhibited by a variety of antioxidant compounds operating by different mechanisms. Because inhibition of lipid peroxidation had minimal effect on DCVC-dependent cytotoxicity, the data suggest that DCVC-induced lipid peroxidation is not a major mechanism in the cytotoxicity induced by this compound.

Aminooxyacetic Acid↗