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Biomedical subjects

A T Davis

Publications and source records attributed to A T Davis.

At least 19 recordsLinked to original sources
PubMed1992

Emergency department laboratory evaluation of children with seizures: dogma or dilemma?

Seizure is a common problem evaluated in pediatric emergency departments. Serum chemistry analysis is often performed as a routine part of the diagnostic evaluation of children who arrive in the ED with seizure. From this retrospective study, we sought to determine 1) how often serum electrolytes (Na, K, Cl, CO2), total calcium, magnesium, ammonia, and glucose chemistries were performed, 2) the frequency of abnormalities detected, and 3) whether abnormalities resulted in a change in patient care. Three hundred eight ED charts from 12 consecutive months were reviewed. Data collected included age, sex, ED diagnosis, medical history, and physical examination. Charts were also reviewed for diagnostic tests ordered and patient management. Children were classified as having febrile (FS) or nonfebrile seizures (NFS) to establish diagnostic evaluation practices for each group as well as to determine rates of laboratory abnormalities. Three hundred eight children were enrolled, 108 (35%) FS and 200 (65%) NFS. The mean ages of FS and NFS patients were 2.1 and 5.7 years, respectively (P less than 0.05, t-test). One hundred twenty-four of 308 (40%) children had at least one test performed; no abnormal test was thought to have caused seizure; none was treated. One hundred five of 308 (34%) were experiencing their first seizure. There was no difference in the likelihood of having a test ordered for children with a first seizure, regardless of seizure category. We concluded that 1) abnormal serum electrolytes, total calcium, magnesium, and glucose rarely cause seizure in children and 2) routine use of these tests in the ED is costly and does not contribute to seizure therapy.

Adolescent↗
PubMed1992

Thymus ontogeny in frogs: T-cell renewal at metamorphosis.

Metamorphosis in amphibians presents a unique problem for the developing immune system. Because tadpoles are free-living, they need an immune system to protect against potential pathogens. However, at metamorphosis, they acquire a variety of new adult-specific molecules to which the tadpole immune system must become tolerant. We hypothesized that Xenopus laevis tadpoles may avoid potentially destructive antiself responses by largely discarding the larval immune system at metamorphosis and acquiring a new one. By implanting triploid (3N) thymuses into diploid (2N) hosts, we examined the influx and expansion of host T-cell precursors in the donor thymus of normally metamorphosing and metamorphosis-inhibited frogs. We observed that donor thymocytes are replaced by host-derived cells during metamorphosis, but inhibition of metamorphosis does not prevent this exchange of cells. The implanted thymuses export T cells to the spleen. This donor-derived pool of cells declines after metamorphosis in normally developing frogs but is retained to a greater extent if metamorphosis is inhibited. These studies confirm previous observations of a metamorphosis-associated wave of expansion of T cells and demonstrate that it is not dependent on the relatively high concentrations of thyroid hormones required for metamorphosis. Although some larval T cells persist through metamorphosis, others may be destroyed or the larval population is significantly diluted by the expanding adult population.

Animals↗
PubMed1991

Attempted suicide in Adelaide and Perth: changing rates for males and females, 1971-1987.

OBJECTIVE: Official rates of attempted suicide in Perth, in 1971-1972 and 1986-1987, were examined, with the aim of documenting changes in the age and sex distribution of persons who attempted suicide over the 15-year period. In addition a survey of all patients presenting to the Royal Adelaide Hospital between 1986 and 1988 aimed to determine whether or not the official figures accurately reflect the number of presentations for attempted suicide. DESIGN AND SETTING: Rates of attempted suicide were calculated from the Hospital Morbidity Data for hospitals in the Perth Statistical Division and from the Inpatient Separations Information System (ISIS) for hospitals in the Adelaide Statistical Division. Rates were expressed for each sex as annual age-specific rates per 100,000 population. The data were age-standardised by the direct method. A survey was completed of all patients presenting to the Royal Adelaide Hospital between 1986 and 1988 after attempted suicide. The findings were compared with the official figures for the Royal Adelaide Hospital and were used to estimate the actual rate of attempted suicide in the Adelaide Statistical Division. RESULTS: In Perth the rate of attempted suicide for males increased from 93 per 100,000 in 1971-1972 to 137 per 100,000 in 1986-1987. The increase was most striking in the age groups 15-19 and 40-44 years. The rates for females decreased from 214 per 100,000 to 195 per 100,000. In Adelaide, from 1986 to 1987, between one-fifth and one-third of persons who attempted suicide and presented to the Royal Adelaide Hospital were not recorded in the ISIS. In 1988, two-thirds were not recorded. We estimated that the real rate of attempted suicide for males in Adelaide was about 180 per 100,000 and for females was about 250 per 100,000. CONCLUSIONS: Our understanding of the epidemiology of attempted suicide is largely based on data which are now out of date. The Perth findings of a 47% rise in rate among males and a 9% fall among females suggest that attempted suicide is no longer a behaviour more associated with females than males. The Adelaide survey data demonstrate that official rates for attempted suicide underestimate the extent of the phenomenon in the community by a significant margin. An attempted suicide register is suggested as a method of overcoming this problem.

Adolescent↗
PubMed1991

The perception of attractiveness: what about the beholders?

This study asked whether there is a relationship between heterosexually relevant dimensions and perception of female attractiveness and femininity. Two hundred and forty-nine undergraduate males rated 22 photographs of young women on these two dimensions. Seventy-nine of these subjects also took the Macho Scale, the Survey of Heterosexual Interactions, and the Bem Sex Role Inventory. Results showed that high Macho subjects viewed most of the photographed women as less attractive than low Macho subjects did. Masculinity/femininity and heterosexual anxiety showed less of a relationship. As predicted, moderately attractive women were described most differently by the high Macho/low Macho raters.

Adult↗
PubMed1991

Cardiac carnitine acyltransferase activities in exercised normal and dystrophic hamsters.

Carnitine acyltransferase activities in the hearts of normal and dystrophic, sedentary and swim exercised hamsters were studied, in order to analyze the relationship between carnitine metabolism and exercise in cardiomyopathy. After 12 weeks, the mean specific activities of cardiac carnitine acetyltransferase (CAT), carnitine octanoyltransferase (COT) and carnitine palmitoyltransferase (CPT) were significantly higher in the dystrophic sedentary group, relative to the normal sedentary group (p less than 0.05). There was no significant effect of exercise on the mean specific activity of the carnitine acyltransferases, compared to the dystrophic or normal sedentary controls. Thus, the improvements in cardiac histopathology due to exercise noted previously are not associated with altered carnitine acyltransferase activity.

Animals↗
PubMed1991

Sodium pivalate treatment reduces tissue carnitines and enhances ketosis in rats.

Sodium pivalate, a compound conjugated to carnitine and excreted in the urine was used to induce a secondary carnitine deficiency. In the first series of experiments, rats received in their drinking water either 20 mmol/L sodium pivalate (experimental) or 20 mmol/L sodium bicarbonate (control) for 4 d, 2 wk, or 8 wk. Tissues and urine were collected, and carnitine concentrations in liver, skeletal muscle, heart, plasma and urine were determined. The total carnitine concentrations in tissues and plasma of pivalate-treated rats were significantly depressed (P less than 0.05) at all time points, except at 4 d for skeletal muscle and at 4 d and 2 wk for liver. The acylcarnitine:free carnitine ratios in urine and plasma of the pivalate-treated animals were significantly higher at all time points relative to the controls. In the second experiment, rats received either the pivalate or the bicarbonate treatments for 15 d followed by a 2-d fast. After fasting, the plasma beta-hydroxybutyrate of pivalate-treated rats was significantly higher relative to controls, but there was no significant difference in plasma glucose concentrations. The reduced plasma and tissue carnitine concentrations, increased acylcarnitine:free carnitine ratio in plasma and urine, and fasting ketosis found in pivalate-treated rats are findings also reported for human secondary carnitine deficiency due to organic acidurias.

Animals↗
PubMed1991

America's first school of nursing: the New England Hospital for Women and Children.

This is a historical research about America's first school of nursing. The purpose of this research is to explore and analyze the philosophy, training methods, and the setting in which nursing education began in America. The methodology included the use of primary sources and a site visit to the New England Hospital for Women and Children, now known as the Dimock Health Center. The findings reveal that through feminist endeavors, and women physicians as nurse educators, the New England Hospital for Women and Children emerged as a leader in training nurses. In addition, this institution is credited with graduating two prominent historical pioneers who were admitted to Nursing's Hall of Fame.

Boston↗
PubMed1991

Increased acylcarnitine clearance and excretion in septic rats.

Carnitine has been hypothesized to be a semi-essential nutrient in the nutrition of critically ill patients. The purpose of this study was to evaluate the effect of sepsis upon carnitine metabolism in the rat, using the model of cecal ligation and puncture. Three treatment groups, septic, sham, and non-operative controls, were used. The septic rats had significantly increased (p less than 0.05) excretion of acylcarnitine and over six-fold higher urinary acylcarnitine/free carnitine ratio, relative to the other two groups. The septic rats also had significantly higher liver and plasma free and total carnitine compared to the other two groups. A possible explanation for the increased urinary acylcarnitine excretion is that carnitine may be acting to remove toxic metabolites from the body. The septic model of cecal ligation and puncture was suitable for the study of carnitine metabolism during sepsis in the rat.

Animals↗
PubMed1991

Behavioral management of psychogenic cough: alternative to the "bedsheet" and other aversive techniques.

The treatment of persistent psychogenic cough, a potentially debilitating condition among pediatric patients, can pose diagnostic and treatment dilemmas. Its treatment by the use of a procedure called reinforced suggestion technique was described previously. The use of an alternative procedure relying upon parental and self-monitoring of coughing and either social or material rewards for decreasing rates of coughing is presented.

Behavior Therapy↗
PubMed1990

The prediction of suicide.

The prediction of suicide remains a major challenge for health professionals. Sociodemographic predictors of the risk of suicide lack specificity: factors such as living alone, being unemployed, or having a physical or mental illness are common, separately or in combination, but suicide is rare. Psychiatric conditions, such as depression, alcohol dependence, schizophrenia and personality disorders, are strongly associated with suicide, but most psychiatrically ill patients do not suicide. Most suicidal patients consult a helping agency within a month of their act and, in practice, successful assessment of the risk of suicide and intervention to prevent it depend on gaining an understanding of the individual patient and developing a therapeutic relationship. More research into the biological, psychological and social factors that distinguish suicidal from non-suicidal individuals is needed. We review key studies that have addressed the issue of suicide prediction, outline the clinician's role in evaluating the risk of suicide in the individual, and suggest directions for future research.

Adult↗
PubMed1990

Failure of BCAA supplementation to promote nitrogen retention in injured patients.

The purpose of this study was to determine if supplementing total parenteral nutrition (TPN) with lipids or the branched chain amino acids (BCAA) leucine, isoleucine, and valine influences nitrogen balance in the injured patient. Four TPN study solutions were used, with each patient receiving two of the solutions for 4 days each. Group A received solutions consisting of 19% and 44% BCAA, with nonnitrogen calories supplied by 100% carbohydrate. Group B received a 7:3 carbohydrate-to-lipid ratio of nonnitrogen calories as a fuel source. Neither BCAA supplementation nor varying fuel substrates promoted a difference in nitrogen retention. The added cost of BCAA supplementation, along with the lack of an effect upon nitrogen accretion, indicates that greater benefits must be demonstrated before widespread use of BCAA supplementation can be recommended in the injured patient.

Amino Acids, Branched-Chain↗
PubMed1990

Plasma and urinary carnitine of obese subjects on very-low-calorie diets.

We evaluated the differential effects of feeding two very-low-calorie diets upon the fractions of plasma and urinary carnitine in obese females. Ten subjects received either diet D1, a 420 kcal/day formula diet, or diet D2, a 500-600 kcal/day meat/fish/poultry diet. Plasma and urinary carnitine levels were determined at the start of the study. After 1 month, plasma carnitine levels were obtained; at 2 months, both plasma and urinary carnitine levels were obtained. Subjects receiving diet D2 showed significantly higher levels of plasma total carnitine over the course of the study (p less than 0.05). Plasma short-chain acylcarnitine esters increased and free carnitine declined significantly in both groups during the study period. Subjects receiving D1 excreted significantly less urinary carnitine than those receiving D2. We conclude that long-term ingestion of very-low-calorie diets causes alterations in plasma carnitine metabolism.

Carnitine↗
PubMed1990

Monoclonal antibodies against nuclear casein kinase NII (PK-N2).

A monoclonal antibody was produced against the nuclear casein kinase II (PK-N2) isolated from rat liver. The antibody was of the IgM class, and showed immunoreactivity towards the higher molecular weight subunit (41K Da) of the protein kinase in Western blots. The antibody was equally reactive towards the PK-N2 isolated from rat ventral prostate indicating that it can recognize the enzyme from different tissues of the rat. The antibody also detected the cytosolic casein kinase II (CK-2) suggesting significant similarity of the antigenic domains in the two forms of this protein kinase. No binding was detected with the nuclear or cytosolic casein kinase I (PK-N1 and CK-1). The antibody did not inhibit the enzyme activity or directly precipitate the enzyme, but when coupled to an affinity matrix and cross-linked with dimethylpimelimidate, it was capable of removing nearly all the PK-N2 activity from solution.

Animals↗
PubMed1990

Taurine concentrations in serum of critically injured patients and age- and sex-matched healthy control subjects.

Sulfur-containing amino acid concentrations were measured in serum of nine previously healthy adult trauma patients after 7 d of taurine-free parenteral nutrition and were compared with fasting serum concentrations in age- and sex-matched healthy subjects. Serum taurine concentrations in the patient group were depressed by 60% relative to control values (P less than 0.05) whereas serum methionine concentrations were significantly higher in the patient group. Serum cysteine concentrations were not significantly different between the two groups. This early decline in serum taurine concentrations in unsupplemented trauma patients suggests that taurine may be essential in the post-injury state.

Adolescent↗
PubMed1990

Tissue trimethyllysine biosynthesis and carnitine content in pregnant and lactating rats fed a lysine-limiting diet.

Previous studies have indicated that carnitine biosynthesis is primarily regulated by the availability of trimethyllysine. The present study investigated the rate of trimethyllysine biosynthesis during pregnancy in rats fed a lysine-restricted diet. Pregnant Sprague-Dawley rats were fed ad libitum a crystalline amino acid diet (18% amino acids) containing either 1.44% or 0.36% lysine. Food intakes were not significantly different between the two groups, either during 19 d of gestation or 12 d of lactation (p greater than 0.05). Trimethyllysine content and synthetic rates were not significantly different between the treatment groups for any of the five tissues tested at either of the two time points. Tissue carnitine content was not consistently affected by dietary lysine content. Liver carnitine content was significantly higher in control rat pups at 12 d of lactation than in pups in the lysine-deficient group. Pups in both groups had peptide-linked trimethyllysine levels in skeletal muscle that were 46% of those seen in the control adults. However, previous reports of higher protein turnover in the neonate would indicate that trimethyllysine is not limiting at this age. Under these experimental conditions, carnitine biosynthesis is not impaired because of restricted availability of trimethyllysine.

Animals↗
PubMed1990

Short-term course of depression following attempted suicide: a preliminary report.

The course of depression over 1 week in patients admitted to hospital following an attempted suicide was examined utilizing a clinical interview, the Zung Self-Rating Depression Scale, the Levine-Pilowsky Depression (LPD) Questionnaire and the Hamilton Rating Scale for Depression. On all measures the group had depression of moderate to marked severity at the time of attempted suicide. In males there was a statistically and clinically significant reduction in severity of depression over 1 week. This trend was also observed in the younger patients. There was no significant change in the frequency of the LPD category endogenous depression, but examination of changes in DSM-III diagnostic frequencies revealed a significant reduction in major affective disorder over 1 week. Symptom changes were also examined. Factors that may have contributed to the observed changes in depression are discussed. Therapeutic implications and further research directions are outlined.

Adjustment Disorders↗
PubMed1990

A multidisciplinary approach to prosthetic management.

This study describes a multidisciplinary team approach to prosthetic management for inpatients. A Communication Management System summary sheet was developed to list all prosthetic devices owned and basic information concerning any existing communication problems. The summary sheet is to be posted in a wooden frame above the patients bed. A member of the nursing staff would be responsible for completing the pertinent data.

Communication↗