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Biomedical subjects

F Davis

Publications and source records attributed to F Davis.

At least 19 recordsLinked to original sources
PubMed2001

Beta-amyloid plaques induce neuritic dystrophy of nitric oxide-producing neurons in a transgenic mouse model of Alzheimer's disease.

A causative role for nitric oxide has been postulated in a number of neurodegenerative diseases. Using histochemical and immunohistochemical methods, we examined the effect of beta-amyloid plaques on nitric oxide-producing cells in transgenic mice which overexpress a mutant human amyloid precursor protein (APP). In 14-month-old animals, nitric oxide synthase (NOS)-positive dystrophic neurites were observed frequently in the cerebral cortex and hippocampus of all of 16 plaque-bearing transgenic animals and in none of 16 wild-type animals. Double labeling of NOS and beta-amyloid revealed that 90% of beta-amyloid plaques were associated with NOS-containing dystrophic neurites. In 7-month-old animals, beta-amyloid plaques were very rare, but those present were frequently associated with NOS-positive neuritic dystrophy. We conclude that beta-amyloid plaques induce neuritic dystrophy in cortical neurons containing NOS in this model of AD, and hypothesize that this finding may be relevant to the mechanism of beta-amyloid neurotoxicity in human AD.

Alzheimer Disease↗
PubMed2000

Anthropometric indices as predictors of survival in AIDS adults. Aquitaine Cohort, France, 1985-1997. Groupe d'Epidémiologie Clinique du Sida en Aquitaine (GECSA).

The aim of the study was to assess the performance of weight related nutritional markers [reported involuntary weight loss (WL) greater than 10%, measured WL and body mass index (BMI)] in predicting survival at AIDS stage. The three anthropometric indices were used as time dependent variables in Cox models to predict survival at AIDS stage. The studied sample included 630 HIV1-infected individuals of a prospective cohort of those 421 died (median survival at AIDS stage: 19.9 months). After adjustment for usual prognostic factors of survival, the reported WL greater than 10% was a pejorative predictor of survival (hazard ratio (HR) 2.4; 95% confidence interval (CI): 1.9-3.0). For measured WL < 5%, between 5 and 10% and > or = 10% of baseline weight compared with no WL, HR were respectively, 1.9 (CI: 1.4-2.6), 3.3 (CI: 2.4-4.4) and 6.7 (CI: 5.2-8.6). The HR of death were 2.2 (CI: 1.6-3.0) for BMI between 16 and 18.4 kg/m2 and 4.4 (CI: 3.1-6.3) for BMI < 16 compared to normal BMI (> or = 18.5). Even a limited WL measured at a given point in time during follow up increases the risk of death at the AIDS stage. Simple cross-sectional measures of BMI have a good predictive value of survival.

AIDS-Related Opportunistic Infections↗
PubMed2000

Blunt splenic injury in adults: Multi-institutional Study of the Eastern Association for the Surgery of Trauma.

BACKGROUND: Nonoperative management of blunt injury to the spleen in adults has been applied with increasing frequency. However, the criteria for nonoperative management are controversial. The purpose of this multi-institutional study was to determine which factors predict successful observation of blunt splenic injury in adults. METHODS: A total of 1,488 adults (>15 years of age) with blunt splenic injury from 27 trauma centers in 1997 were studied through the Multi-institutional Trials Committee of the Eastern Association for the Surgery of Trauma. Statistical analysis was performed with analysis of variance and extended chi2 test. Data are expressed as mean +/- SD; a value of p < 0.05 was considered significant. RESULTS: A total of 38.5 % of patients went directly to the operating room (group I); 61.5% of patients were admitted with planned nonoperative management. Of the patients admitted with planned observation, 10.8% failed and required laparotomy; 82.1% of patients with an Injury Severity Score (ISS) < 15 and 46.6% of patients with ISS > 15 were successfully observed. Frequency of immediate operation correlated with American Association for the Surgery of Trauma (AAST) grades of splenic injury: I (23.9%), II (22.4%), III (38.1%), IV (73.7%), and V (94.9%) (p < 0.05). Of patients initially managed nonoperatively, the failure rate increased significantly by AAST grade of splenic injury: I (4.8%), II (9.5%), III (19.6%), IV (33.3%), and V (75.0%) (p < 0.05). A total of 60.9% of the patients failed nonoperative management within 24 hours of admission; 8% failed 9 days or later after injury. Laparotomy was ultimately performed in 19.9% of patients with small hemoperitoneum, 49.4% of patients with moderate hemoperitoneum, and 72.6% of patients with large hemoperitoneum. CONCLUSION: In this multicenter study, 38.5% of adults with blunt splenic injury went directly to laparotomy. Ultimately, 54.8% of patients were successfully managed nonoperatively; the failure rate of planned observation was 10.8%, with 60.9% of failures occurring in the first 24 hours. Successful nonoperative management was associated with higher blood pressure and hematocrit, and less severe injury based on ISS, Glasgow Coma Scale, grade of splenic injury, and quantity of hemoperitoneum.

Adult↗
PubMed2000

Tornado disaster in rural Georgia: triage response, injury patterns, lessons learned.

Our objective was to characterize the medical response and injury patterns from a recent tornado disaster in rural southeastern Georgia. We conducted a retrospective review of 11 patients treated at a Level I trauma center after sustaining injuries due to an April 9, 1998 F3 tornado. Data were obtained from trauma registry and medical records. Of 11 victims, 8 (73%) were male. Ages ranged from 5 to 54 years. Two patients were triaged directly by military helicopter, six arrived as secondary triage from local rural hospitals (2 by air, 4 by ground), and three arrived by delayed secondary transfer. Six patients were thrown by the tornado, and five were struck by flying debris. All victims were either in exposed areas or mobile homes. Injuries by anatomic region included the chest (45%), abdomen (27%), extremity (91%), and head (45%). Nine (82%) of the patients required surgical intervention. These included three laparotomies, one thoracotomy, six orthopedic procedures, and one neurosurgical procedure. The average Injury Severity Score (ISS) was 23. Among patients who were thrown mean ISS was 31; among those struck by debris, mean ISS was 12. Hemodynamically significant pelvic fractures occurred in three patients (27%). The major complication, sepsis due to Serratia marcescens was seen in three patients, all of whom had been thrown and had clinically significant wound contamination. Both patients who died had Serratia sepsis and multiorgan system failure. The injuries and inclement weather characteristic of tornado disasters stress regional trauma triage responses, cause significant injury, and disrupt communities. Injury patterns involve multiple systems and require coordinated efforts among caretakers. Infectious complications are common and frequently involve Gram-negative bacilli and are associated with soil-contaminated wounds. Trauma severity increases if the victim is thrown rather than struck by flying debris.

Adolescent↗
PubMed1999

The role of ultrasound in patients with possible penetrating cardiac wounds: a prospective multicenter study.

BACKGROUND: Ultrasound is quickly becoming part of the trauma surgeon's practice, but its role in the patient with a penetrating truncal injury is not well defined. The purpose of this study was to evaluate the accuracy of emergency ultrasound as it was introduced into five Level I trauma centers for the diagnosis of acute hemopericardium. METHODS: Surgeons or cardiologists (four centers) and technicians (one center) performed pericardial ultrasound examinations on patients with penetrating truncal wounds. By protocol, patients with positive examinations underwent immediate operation. Vital signs, base deficit, time from examination to operation, operative findings, treatment, and outcome were recorded. RESULTS: Pericardial ultrasound examinations were performed in 261 patients. There were 225 (86.2%) true-negative, 29 (11.1%) true-positive, 0 false-negative, and 7 (2.7%) false-positive examinations, resulting in sensitivity of 100%, specificity of 96.9%, and accuracy of 97.3%. The mean time from ultrasound to operation was 12.1+/-5 minutes. CONCLUSION: Ultrasound should be the initial modality for the evaluation of patients with penetrating precordial wounds because it is accurate and rapid.

Acute Disease↗
PubMed1998

Radiologic evaluation of the acute abdomen in the patient with acquired immunodeficiency syndrome (AIDS): the role of CT scanning.

Abdominal complaints are common in the HIV-infected patient, and the signs and symptoms of disease may be masked by concurrent illness and a weak immune response, making accurate diagnosis difficult. Patients with acquired immunodeficiency syndrome (AIDS) are susceptible to diseases common to the general population; however, their generalized state of immunodeficiency places them at increased risk for many unusual disorders, predominately infectious and neoplastic. Radiologic evaluation, in particular, computed tomography (CT) with its ability to image the entire abdomen and pelvis, plays a crucial role in the prompt and accurate diagnosis and treatment of these patients.

AIDS-Related Opportunistic Infections↗
PubMed1998

Musculoskeletal complications of the patient with acquired immunodeficiency syndrome (AIDS): CT evaluation.

Musculoskeletal disorders are infrequent complications of HIV infection in this country. However, AIDS patients are susceptible to a wide range of musculoskeletal complications, from the common to the otherwise uncommon. The following is a summary of some of the more frequently encountered musculoskeletal manifestations of these disorders within the HIV-positive community and their associated imaging characteristics.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Brain tumor survival: results from the National Cancer Data Base.

Hospital-based data reported to the National Cancer Data Base (NCDB) were available for over 60,000 patients with a primary brain tumor diagnosed from 1985-1988 and 1990-1992. The most common histologies were glioblastomas, astrocytomas and meningiomas. Five-year survival rates for these tumors were 2%, 30% and 70% respectively. Histology, age at diagnosis, behavior, and location were important variables in estimating survival. Comparisons with population-based registry data suggest that the malignant tumors are well represented in NCDB, but the benign histologies are under-reported. Survival estimates for the malignant tumors are comparable to previously reported studies. The NCDB provides recent information on brain tumor distribution and survival patterns not available in other large databases.

Adolescent↗
PubMed1998

The descriptive epidemiology of craniopharyngioma.

OBJECT: In this report the authors describe the epidemiology of craniopharyngioma. METHODS: The incidence of craniopharyngioma in the United States was estimated from two population-based cancer registries that include brain tumors of benign and borderline malignancy: the Central Brain Tumor Registry of the United States (CBTRUS) and the Los Angeles county Cancer Surveillance Program. Information on additional pediatric tumors was available from the Greater Delaware Valley Pediatric Tumor Registry (GDVPTR). The overall incidence of craniopharyngioma was 0.13 per 100,000 person years and did not vary by gender or race. A bimodal distribution by age was noted with peak incidence rates in children (aged 5-14 years) and among older adults (aged 65-74 years in CBTRUS and 50-74 years in Los Angeles county). Survival information was available from GDVPTR and the National Cancer Data Base (NCDB), a hospital-based reporting system. In the NCDB, the 5-year survival rate was 80% and decreased with older age at diagnosis. Survival is higher among children and has improved in recent years. CONCLUSIONS: Craniopharyngioma is a rare brain tumor of uncertain behavior that occurs at a rate of 1.3 per million person years. Approximately 338 cases of this disease are expected to occur annually in the United States, with 96 occurring in children from 0 to 14 years of age.

Adolescent↗
PubMed1998

Managing care in an integrated delivery system via an Intranet.

The CareGroup Provider Service Network is a managed care contracting organization which provides central administrative services for over 1800 physicians and 200,000 managed care lives. Services include utilization management, disease management and credentialing for the entire network. The management model of the Provider Service Network empowers local physician groups with information and education. To meet the managed care information needs of the network, we implemented an intranet-based executive information system, PSNWeb, which retrieves data from a managed care data warehouse. The project required the integration of diverse technologies and development of a complex security/confidentiality infrastructure to deliver information to 8 major clinician groups, each with different information needs.

Computer Security↗
PubMed1997

The effect of intravenous administration of a chimeric anti-IgE antibody on serum IgE levels in atopic subjects: efficacy, safety, and pharmacokinetics.

CGP 51901 is a non-anaphylactogenic mouse/human chimeric anti-human IgE antibody that binds to free IgE and surface IgE of IgE-expressing B cells but not to IgE bound to high affinity IgE receptors (Fc epsilonR1) on mast cells and basophils or low affinity IgE receptors (Fc epsilonR2) on other cells. A phase 1 double-blind, placebo-controlled, single dose study with doses of 3, 10, 30, and 100 mg of CGP 51901 was conducted in 33 pollen-sensitive subjects who had raised levels of serum IgE and received either intravenous CGP 51901 or placebo. The administration of CGP 51901 was well tolerated and resulted in a decrease of serum free IgE levels in a dose-dependent manner, with suppression after 100 mg of CGP 51901 reaching > 96%. Time of recovery to 50% of baseline IgE correlated with the dose of administered antibody and ranged from a mean of 1.3 d for the 3 mg to 39 d for the 100 mg dose. Total IgE, comprised of free and complexed IgE, increased as stored and newly synthesized IgE bound to CGP 51901. Complexed IgE was eliminated at a rate comparable with the terminal half-life of free CGP 51901 (11-13 d at all doses). Only one subject showed a weak antibody response against CGP 51901. We conclude that the use of anti-human IgE antibody is safe and effective in reducing serum IgE levels in atopic individuals and provides a potential therapeutic approach to the treatment of atopic diseases.

Adolescent↗
PubMed1997

Evaluation of internal alpha-particle radiation exposure and subsequent fertility among a cohort of women formerly employed in the radium dial industry.

This study examined the effect of internal exposure to alpha-particle radiation on subsequent fertility among women employed in the radium dial industry prior to 1930, when appreciable amounts of radium were often ingested through the practice of pointing the paint brush with the lips. The analysis was limited to women for whom a radium body burden measurement had been obtained and who were married prior to age 45 (n = 603). Internal radiation dose to the ovary was calculated based on initial intakes of radium-226 and radium-228, average ovarian mass, number and energy of alpha particles emitted, fraction of energy absorbed within the ovary, effective retention integrals and estimated photon irradiation. Time between marriage and pregnancy, number of pregnancies and number of live births served as surrogates for fertility. Radiation appeared to have no effect on fertility at estimated cumulative ovarian dose equivalents below 5 Sv; above this dose, however, statistically significant declines in both number of pregnancies and live births were observed. These trends persisted after multivariable adjustment for potential confounding variables and after exclusion of subjects contributing a potential classification or selection bias to the study. Additionally, the high-dose group experienced fewer live births than would have been expected based on population rates. There were no differences in time to first pregnancy between high- and low-dose groups. These results are consistent with earlier studies of gamma-ray exposures and suggest that exposure to high doses of radiation from internally deposited radium reduces fertility rather than inducing sterility.

Abortion, Spontaneous↗
PubMed1996

Ethnic variation in the incidence of stomach cancer in Illinois, 1986-1988.

Wide ethnic and geographic variation in stomach cancer incidence has been reported in Eastern and Western countries. Stomach cancer is reported to be the most common malignant neoplasm in Asia, specifically, China, Japan, and Korea. In contrast, stomach cancer incidence in the United States among Caucasians is low and among blacks, moderate to low. Only one other study has directly compared the rates of stomach cancer in the three ethnic groups (i.e., white, African American, and immigrant Korean) living in the same region. The authors extend their investigation by comparing the incidence rate of stomach cancer among the same three ethnic groups in the state of illinois from 1986 to 1988. In this study, the incidence of stomach cancer was observed to be lowest in whites, intermediate in African Americans, and highest in immigrant Koreans. The overall 3-year cumulative incidence rate from 1986 to 1988 was 62.6/100,000 (95% confidence interval (CI) 38.6-86.7), 28.2/100,000 (95% CI 25.7-31), and 22.5/100,000 (95% CI 21.5-23.5) for immigrant Koreans, African Americans, and whites, respectively. The 3-year age-adjusted cumulative incidence rate for immigrant Koreans (172/100,000) was approximately four-and eightfold higher than for African Americans (41/100,000) and whites (21/100,000). The incidence of stomach cancer increased as a function of age in both sexes. Although a higher rate was observed in males than in females, these rates were four-and eightfold higher in African Americans and immigrant Koreans, when compared with their white counterparts in both sexes. Despite a substantial reduction of stomach cancer incidence in the United States and other Western countries, it remains the most frequent malignancy in native and immigrant Koreans. The high rate of stomach cancer in immigrant Koreans compared with African Americans and white populations residing in Illinois indicates either a drastically disproportionate undercount of immigrant Koreans in the 1990 census or a profound genetic-environmental interaction.

Adolescent↗
PubMed1996

Applying the realized probability of dying to cancer survival.

Age comparisons of survival in cancer cohorts generally utilize relative survival rates, which are based on indicators of the probability of survival for a given number of years after diagnosis. Cancer relative survival rates for the same number of years tend to decline as age at diagnosis increases. However, the same number of years of survival reflects higher relative longevity at older ages than at younger ages. The realized probability of dying (RPD) is a survival measure that expresses individual survival time after diagnosis relative to the survival distribution of an age-, race-, and sex-specific reference population, in effect weighing individual survival time more heavily as age at diagnosis increases. The purpose of this study was to apply the RPD as a survival measure in cancer epidemiology. Two cohorts of cancer patients, white males with prostate cancer and white females with breast cancer, aged 55 years and over at diagnosis, were followed for 15 years. Although older subjects survived less time after diagnosis than younger subjects, they achieved more favorable RPD values. We present survival analysis methods for analyzing the RPD in this population, an approach not previously used with this measure. The implications for use of the RPD in cancer epidemiology are discussed.

Breast Neoplasms↗