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Biomedical subjects

A T Davis

Publications and source records attributed to A T Davis.

At least 73 records · Page 4Linked to original sources
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↗
PubMed1989

Carnitine femoral arterial-venous differences in the stressed critically ill.

Femoral arterial and venous carnitine concentrations from critically ill patients were measured in order to determine if the large urinary carnitine excretions seen in these patients was associated with a net loss of carnitine from skeletal muscle. Bloods were drawn two or three times during the 7-day study period. A 24-hr urine sample was obtained on the same day. The arterial-venous difference for free carnitine plus short chain acylcarnitine was -2.8 +/- 0.9 microM (means +/- SEM), and -2.7 +/- 1.0 microM for total carnitine. Both values were significantly less than zero (p less than 0.05). Median urinary free carnitine excretion was 1237 mumol/day while the median acylcarnitine excretion was 544 mumol/day. We conclude that skeletal muscle in these patients is in negative carnitine balance, and is at least one source of the increase in carnitine excretion seen in critically ill patients.

Adult↗
PubMed1989

Fractional contributions to total carnitine in the neonatal rat.

This study was designed to determine the fraction of tissue total carnitine derived from the mother in utero, from milk, and from fetal and neonatal de novo synthesis. Female rats were offered drinking water ad libitum containing either tritium or [14C]-labeled carnitine (0.1 mCi/mmol, 5 mM). The rats were mated, and after birth, the pups of females given the tritium-labeled water were switched with the pups of rats given the [14C]-labeled carnitine (cross-fostering). Analyses of neonatal tissue total carnitine in five tissues were determined on d 0, 1, 2, 5, 10, and 20 after birth. Carnitine derived from neonatal de novo synthesis remained relatively constant from birth throughout the 20 d period, ranging from 26% in liver to 50% in the heart at d 0. The contribution from milk carnitine rose rapidly after birth until d 5, at which time it became relatively constant, ranging from 40.8% in heart to 55.4% in kidney at d 20. The fetus is a major contributor to its own tissue carnitine. Nevertheless, the infant rat is dependent upon external sources of carnitine in order to maintain tissue carnitine levels.

Animals↗
PubMed1989

Psychotic states associated with disorders of thyroid function.

Thyroid-related psychoses continue to pose diagnostic and treatment challenges for clinicians. Two case histories illustrate diverse clinical states associated with hyper- and hypo-thyroidism respectively and highlight the need to consider the possibility of thyroid disorder in all patients presenting with acute psychotic mental disorder. They also demonstrate treatment methods directed at control of psychotic symptoms and restoration of an euthyroid state.

Adult↗
PubMed1988

Increased plasma carnitine in trauma patients given lipid-supplemented total parenteral nutrition.

The purpose of this study was to determine the effects of altering the fuel substrate mix of total parenteral nutrition (TPN) on plasma and urinary carnitine in trauma patients. TPN solutions were either 100% carbohydrate (CHO) based or lipid based (70% CHO, 30% lipid). There were statistically significant (p less than 0.05) increases in plasma levels of free carnitine, short-chain acyl carnitine, and total carnitine in trauma patients receiving lipid-based TPN. No significant differences in urinary carnitine excretion were noted between groups. We conclude that the use of lipids in the TPN of trauma patients leads to an alteration in plasma carnitine metabolism.

Adult↗
PubMed1988

Cryoprecipitates in Kawasaki syndrome: association with coronary artery aneurysms.

Cryoprecipitates are postulated to play a role in the pathogenesis of several vasculitis illnesses and infectious diseases. To investigate the presence of cryoprecipitates in Kawasaki syndrome, we studied sera from 25 children with acute Kawasaki syndrome. None of the subjects was treated with intravenous gamma-globulin. Cryoprecipitates were detectable in sera of 11 of 25 (44%) children studied. The mean (+/- SE protein concentration of the cryoprecipitates was 88.0 (+/- 20.2) micrograms/ml serum. Cryoprecipitates consisted primarily of IgG and IgM; no complement components were detected but highly sensitive methods were not used. The presence of cryoprecipitates in the serum of children with acute Kawasaki syndrome was associated with the subsequent development of coronary artery aneurysms detected by echocardiogram (P less than 0.05). There was no association between detectable cryoprecipitates and either peak platelet count or erythrocyte sedimentation rate. In one patient, measurement of cryoprecipitates in serial samples showed a reduction in concentrations that paralleled subsidence of disease activity. We speculate that cryoprecipitates may be a marker for increased risk of coronary aneurysm formation and may play a role in the pathogenesis of the cardiac disease in Kawasaki syndrome.

Child↗
PubMed1988

Carving a niche--the general academic pediatrician as consultant. Part I: The referring physicians and their patients.

The role of the general pediatrician as a specialist is often unclear to the majority of physicians and patients. The role of the general academic pediatrician (GAP) as a consulting subspecialist also is in need of definition. We surveyed a consultation service staffed primarily by three GAPs in our tertiary care children's hospital. During the 12-month survey, 275 patients with a mean age of 5.6 years were evaluated. The mean duration of the chief complaint prior to the initial visit was 12.3 months. A total of 254 (92%) were evaluated initially as outpatients; of these, 20 (8%) were eventually hospitalized. Only 29 percent of the patients were referred to pediatric subspecialists. GAPs acting as consultants in a tertiary care setting most often see patients with long-standing complaints that do not require hospitalization or subspecialist referral, but their role at times is expanded to include more acute and more complex problems. Referrals may come from primary care physicians or from tertiary care subspecialists, particularly surgeons, or by self-referral from the patients' families.

Adolescent↗
PubMed1988

Carving a niche: the general academic pediatrician as consultant. Part II: Academic, financial, and educational concerns.

The General Academic Pediatrician (GAP) may act as a consultant to both primary care pediatricians and tertiary care subspecialists. The authors surveyed a consultation service staffed by three GAP's in a tertiary care children's hospital. The service was financially successful and generated new sources of referrals for its parent institution. The increasing complexity of the role of a GAP within a department of pediatrics in regards to clinical, teaching, and research activities is explored.

Chicago↗
PubMed1988

A turbidimetric method for fibronectin assay in the dog.

An immunoturbidimetric method, using spectrophotometry, for the assay of canine plasma fibronectin concentration was compared with the immunoelectrophoretic method. The spectrophotometric method (S) correlated positively (r = 0.7) and significantly (P less than 0.01) with the immunoelectrophoretic method (I). The regression equation was S = 0.37I + 53. Ninety-five percent confidence levels for the regression line were calculated to allow detection, by spectrophotometry, of plasma fibronectin concentrations outside the normal range.

Animals↗
PubMed1987

Antibiotic administration to treat possible occult bacteremia in febrile children.

We performed a prospective, randomized, placebo-controlled, double-blind clinical trial of antibiotic administration to treat possible occult bacteremia in febrile children. A total of 955 children aged 3 to 36 months with temperatures greater than or equal to 39.0 degrees C and no focal bacterial infection were enrolled at the emergency departments of two children's hospitals from January 1982 until July 1984. Blood samples for culture were obtained, and the children were randomly assigned to receive either oral amoxicillin or placebo and were restudied approximately 48 hours after enrollment. Data were also collected on 228 children who could not be randomly assigned. Twenty-seven of the randomly assigned children (2.8 percent) had bacteremic infections with pathogenic organisms (Streptococcus pneumoniae, Haemophilus influenzae, and salmonella). There were no differences in the incidence of major infectious morbidity associated with bacteremia between the antibiotic and placebo groups--2 of 19 patients (10.5 percent) in the antibiotic group and 1 of 8 (12.5 percent) in the placebo group--although the power for this comparison was low. Antibiotics reduced fever (P less than 0.005) and improved the clinical appearance (P = 0.07) in the children with bacteremia but not in those without bacteremia. Although there were no statistically significant differences in the incidence of side effects, diarrhea tended to occur more often in the patients treated with amoxicillin (15 vs. 11 percent, P less than 0.10). We conclude that our data do not support the routine use of standard oral doses of amoxicillin in febrile children who do not have evidence of focal bacterial disease.

Amoxicillin↗