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Biomedical subjects

S K Davis

Publications and source records attributed to S K Davis.

88 records · Page 5Linked to original sources
PubMed1990

Modulation of growth hormone (GH) secretion and GH mRNA levels by GH-releasing factor, somatostatin and secretagogues in cultured bovine adenohypophysial cells.

The effects of endogenous hypothalamic neurohormones and activators of second messenger signalling systems on the secretion of GH and on cell content of GH mRNA of cultured bovine adenohypophysial cells were studied. Synthetic bovine GH-releasing factor (bGRF; 100 nmol/l) increased secretion of GH by bovine adenohypophysial cells five-fold relative to control. Forskolin (an adenyl cyclase activator; 10 mumol/l) and the synthetic cyclic AMP analogue dibutyryl cyclic AMP (dbcAMP; 1 mmol/l) increased secretion of GH by 1.9- and 1.7-fold respectively, relative to control. The protein kinase C activator phorbol 12-myristate 13-acetate (PMA), provided at 1 mumol/l or 10 nmol/l, increased GH secretion by 6.6- and four-fold respectively, relative to control. Somatostatin-14 (SRIF-14) attenuated basal, bGRF-, forskolin- and dbcAMP-stimulated secretion of GH by 40, 49, 47 and 67% respectively, but did not, however, diminish PMA-stimulated GH secretion. The content of GH mRNA in cultured bovine adenohypophysial cells increased 2.2-, 1.7- and 3.2-fold by administration of bGRF, forskolin and PMA respectively, relative to control. Although GH mRNA content was unchanged by SRIF-14 treatment relative to control, SRIF-14 did reduce bGRF-stimulated bGH mRNA content by 67%. This study demonstrates that mechanisms subserving GH secretion in bovine adenohypophysial cells (e.g. adenyl cyclase and protein kinase C) may be coupled with mechanisms which regulate expression of the GH gene or with factors affecting message stability.

Animals↗
PubMed1990

Adipose tissue cellularity and muscle growth in young steers fed the beta-adrenergic agonist clenbuterol for 50 days and after 78 days of withdrawal.

Angus steers (n = 40; approximate weight = 300 kg) were administered the beta-adrenergic agonist clenbuterol for 50 d (7 mg.hd-1.d-1), followed by a 78-d withdrawal period. Carcass fatness variables did not differ (P greater than .05) between treated and control animals either after 50 d or after 128 d. Weights of the 9-10-11th rib longissimus muscle were 25% larger, and longissimus cross-sectional areas were 28% greater, in clenbuterol-fed steers relative to controls from 0 to 50 d (P less than .05). After withdrawal these measurements increased no further in the treated steers. Marbling scores were decreased (P less than .05) in clenbuterol-fed steers after 50 d of treatment; this effect persisted after 128 d of withdrawal from treatment. Shear force values were increased 19% (P less than .05) by feeding clenbuterol for 50 d and remained greater (P less than .05) in treated animals after 128 d. Subcutaneous adipocytes in clenbuterol-fed steers were smaller (P less than .05) than those of controls after 50 d, and this effect was still apparent after the 78-d withdrawal period. Rates of lipogenesis did not differ (P less than .05) between treated and control animals at any time. Perirenal (p.r.) adipocytes were smaller (P less than .05) in treated animals after 50 d, but this effect disappeared by the end of the experiment. There was no indication of a bimodal distribution of smaller s.c. or p.r. adipocytes in either of the treatment groups. Apparent hyperplasia of s.c. adipocytes occurred in the area of the 9-10-11th rib in both treated (P less than .10) and control animals (P less than .05) from 0 to 50 d on trial. Within treated animals there was a significant increase (P less than .05) in total adipocytes in this depot during the withdrawal period. Although the effects of clenbuterol on muscle growth generally were reversed after 78 d, the effects of the beta-adrenergic agonist on adipose tissue development were more permanent.

Adipose Tissue↗
PubMed1990

Clomipramine: an antiobsessional tricyclic antidepressant.

The chemistry, pharmacology, pharmacokinetics, adverse effects, and dosage of clomipramine hydrochloride are described, and clinical studies of the use of clomipramine in treating obsessive-compulsive disorder (OCD), other psychiatric conditions, and chronic pain are reviewed. Clomipramine hydrochloride, a tricyclic antidepressant, is a potent inhibitor of serotonin reuptake and may affect dopaminergic neurotransmission, suppress rapid eye movement sleep, produce changes in electrocardiograms, and elevate plasma prolactin. The drug is well absorbed from the gastrointestinal tract and undergoes extensive first-pass metabolism. Peak plasma concentrations occur three to four hours after a 150-mg oral dose. The mean elimination half-life is 39 hours. Some 66% of a dose is excreted in the urine, the remainder being eliminated in the feces. In clinical trials, clomipramine was significantly more effective than placebo, clorgiline, amitriptyline, imipramine, and doxepin in ameliorating the symptoms of OCD. Initial effects are seen at four weeks; improvement may continue for up to 18 weeks. Clomipramine may also be effective in treating panic attacks, phobias, depression, and chronic pain. The most common adverse effects of clomipramine are anticholinergic; others include nausea, seizures, and sexual difficulties. Interactions between clomipramine and barbiturates, haloperidol, monoamine oxidase inhibitors, and cigarette smoking have been documented. The usual initial adult dosage is 25-50 mg/day, titrated gradually to 250 mg/day if necessary. Clomipramine hydrochloride is a welcome new agent for the treatment of obsessive-compulsive disorder. Although its adverse-effect profile is like that of other tricyclic antidepressants, sexual dysfunction and seizures may be more frequent with this agent and limit its use.

Clomipramine↗
PubMed1989

Isolation, characterization, and expression of fatty acid binding protein in the liver of Gallus domesticus.

1. Fatty acid binding protein (FABP) was isolated from chicken liver cytosol. 2. Apparent molecular weight, pI, functional activity, and hybridization of a rat hFABP cDNA probe with chicken liver mRNA suggest that chicken liver FABP is structurally related to hepatic FABP (hFABP) previously isolated and characterized in the rat. 3. Fatty acids bound to liver FABP affect the electrophoretic nature of FABP. 4. Levels of liver FABP mRNA isolated from chickens at various stages of development parallel developmental alterations in lipid metabolism, being highest in day old chicks and laying hens versus juvenile birds.

Amino Acids↗
PubMed1989

Isolation and characterization of two fatty acid binding proteins from intestine of Gallus domesticus.

1. Two distinct fatty acid binding proteins (FABPs) were isolated and characterized from chicken duodenal mucosa. 2. Molecular weight, functional activity, immunospecificity, mRNA expression, and amino acid composition data for the 14 kDa chicken intestinal FABP was similar, yet not identical, to that of a previously isolated chicken liver FABP. 3. Bound fatty acids were shown to produce isoforms of the 14 kDa intestinal protein but not the larger molecular weight intestinal FABP.

Amino Acids↗
PubMed1989

Elevation of a specific mRNA in longissimus muscle of steers fed ractopamine.

To address the hypothesis that some classes of growth promoters stimulate muscle protein synthesis in growing cattle, 23 crossbred steers were fed diets containing the phenethanolamine growth promoter ractopamine in a 140-d feeding trial. Steers received either no ractopamine, .18 or .36 mg.kg BW-1.d-1 ractopamine for 140 d or .36 or .72 mg.kg BW-1.d-1 ractopamine for 56 d. Longissimus muscle was obtained at slaughter and frozen in liquid N2. RNA was extracted by homogenization of pulverized frozen muscle in guanidinium isothiocyanate and centrifugation through cesium chloride. Polyadenylated mRNA was extracted by capture on oligo-dT columns. Ractopamine had no effect on total RNA or mRNA concentrations (P greater than .25). Hybridization of the RNA to a putative myosin light chain-1/3 (MLC-1/3) cDNA clone in a Northern blot indicated one heavy band (approximately 1 kb) with no evidence of extensive destruction of the RNA. A second, minor band (approximately 3 kb) also was observed in some samples. The MLC-1/3 cDNA clone was hybridized to 1- or 5-micrograms samples of total RNA, and the intensity of the resultant autoradiographs was quantified by laser densitometry. There was a statistical correlation between MLC-1/3 mRNA-micrograms RNA-1 and longissimus cross-sectional area (P less than .05) and average daily gain (P less than .025). The results suggest that ractopamine either increased the transcription of the putative MLC-1/3 gene and(or) increased the stability of MLC-1/3 mRNA in bovine longissimus muscle, either of which could result in an increase in specific myofibrillar protein synthesis.

Analysis of Variance↗
PubMed1988

Effect of data collection method on results of serum digoxin concentration audit.

The appropriateness of serum digoxin concentration (SDC) orders was evaluated with respect to indication for use, sampling time, and action taken by physicians when the reported SDC was out of the normal therapeutic range; the effect of the two data-collection methods used (retrospective and concurrent audits) on the results was studied. Criteria for the appropriate use of SDCs were approved by the medical staff through the pharmacy and therapeutics committee. Patients on adult medicine services were entered into the study as daily SDC determinations were reported by the clinical laboratory. Most of the SDCs were evaluated using approved criteria by primary pharmacist clinicians who were concurrently monitoring drug therapy and participating with the treatment team. A retrospective audit of the same patients was conducted, using only chart review. A total of 134 SDCs involving 78 patients were evaluated. Concurrent-audit results indicated that 18.7% of the SDCs were ordered without an appropriate indication, 16.4% were sampled incorrectly with respect to proper timing, and 8.2% did not result in dosage adjustments when indicated. With respect to appropriate sampling time and overall use of SDCs, significantly more SDCs met the standards under concurrent audit than under retrospective audit. The retrospective chart review method of auditing may not detect as much pertinent information as is desirable.

Concurrent Review↗
PubMed1987

Evolution of the 28S ribosomal RNA gene in anurans: regions of variability and their phylogenetic implications.

Fifteen restriction sites were mapped to the 28S ribosomal RNA gene of individuals representing 54 species of frogs, two species of salamanders, a caecilian, and a lungfish. Eight of these sites were present in all species examined, and two were found in all but one species. Alignment of these conserved restriction sites revealed, among anuran 28S rRNA genes, five regions of major length variation that correspond to four of 12 previously identified divergent domains of this gene. One of the divergent domains (DD8) consists of two regions of length variation separated by a short segment that is conserved at least throughout tetrapods. Most of the insertions, deletions, and restriction-site variations identified in the 28S gene will require sequence-level analysis for a detailed reconstruction of their history. However, an insertion in DD9 that is coextensive with frogs in the suborder Neobatrachia, a BstEII site that is limited to representatives of two leptodactylid subfamilies, and a deletion in DD10 that is found only in three ranoid genera are probably synapomorphies.

Animals↗
PubMed1987

Use of staff pharmacists to reduce the inappropriate use of parenteral histamine-2 antagonist therapy.

This article describes the development and implementation of a target drug monitoring program using staff pharmacists as primary data collectors. This target drug program increased professional activities of staff pharmacists and showed how pharmacists could make an impact on drug therapy both financially and clinically. Parenteral histamine-2 antagonists were selected based upon amount of use and potential for inappropriate use and dosing. Criteria were developed in conjunction with the Pharmacy and Therapeutics Committee and medical staff. In phase I, pharmacists prospectively monitored all patients receiving parenteral cimetidine and ranitidine. Therapy was reviewed for justification of parenteral therapy (vs. oral), dosage adjustment in renal impairment, and monitoring of specific drug-drug interactions with cimetidine or ranitidine. During this phase, pharmacists collected data without intervening. Results from phase I and a program proposal for phase II were approved by the Pharmacy and Therapeutics Committee. Phase II consisted of the same monitoring procedures; however, when inconsistencies with the criteria were identified in one of the three categories, "chart education sheets" were placed in the chart. Results from phase I indicated a potential for cost savings. During phase II, 45% of the inappropriate parenteral therapy was changed to oral therapy, representing an annualized cost savings of $23,321 in this 540-bed hospital. The pharmacists were also successful in adjusting doses in renal impairment and monitoring potential drug interactions. The target drug program has proved to be an effective method of educating physicians and decreasing costs to the institution without the use of additional personnel.

Cost Control↗
PubMed1986

Perceptions by the aged of crime, criminals, and the criminal justice system.

A general fear of crime victimization led to modified activities in the community and feelings of relative safety in their own area for 132 elderly respondents on a 24-item questionnaire. They held sympathetic views of crime perpetrators as disadvantaged victims of society themselves, but came to the unlikely conclusions that more police control and harsher prison sentences are needed.

Aged↗
PubMedDate not supplied

The polled locus maps to BTA1 in a Bos indicus x Bos taurus cross.

Two hundred and nine reciprocal backcross and F2 progeny produced by embryo transfer from Angus (Bos taurus) and Brahman (Bos indicus) parents and their 60 parents and grandparents were utilized to localize the locus (POLL) responsible for the polled phenotype in a genetic map of bovine chromosome 1. Progeny were scored for polled, scurred, and horned phenotypes at 1 year of age and again following skull disection at slaughter at 20 months of age. Phenotype frequencies were independent of gender. One hundred and forty-two informative meioses for POLL and 13 microsatellite loci with an average of 267 informative meioses per locus contributed to a genetic map spanning 124.6 cM with an average interval of 9.6 cM. POLL mapped proximal to the centromere and 4.9 cM from TGLA49 supporting a previous study that employed two anonymous microsatellites. Difficulties in discriminating between scurred and horned phenotypes indicate that bracketing markers will be essential for refining the model for inheritance of the horned, scurred, and polled phenotypes and for effective marker assisted selection (MAS) for polled.

Animals↗
PubMedDate not supplied

Comprehensive interventions for affecting the parenting effectiveness of chemically dependent women.

Research suggests that the ineffective parenting techniques used by many chemically dependent women may be as much a result of pre-existing conditions, such as traumatic childhood experiences, negative affective states, and ineffective social support networks, as from actual substance abuse. Comprehensive interventions are needed that address these pre-existing conditions along with drug and alcohol issues to maximize the parenting outcomes of chemically dependent women. The sequence of appropriate interventions in the areas of assessments, treatment, parenting education, and pregnancy and health needs as they relate to the quality of parenting among chemically dependent women are discussed. The role of the health care provider is discussed, and suggestions about referrals and resources are identified.

Child Care↗
PubMedDate not supplied

Increasing disparity in knowledge of cardiovascular disease risk factors and risk-reduction strategies by socioeconomic status: implications for policymakers.

During the 1980s extensive local and national cardiovascular health promotion campaigns were implemented to improve knowledge of risk reduction. This study analyzed changes from 1980 to 1990 in knowledge of acquired cardiovascular risk factors (i.e., actual, objective knowledge of adverse lifestyle factors affecting cardiovascular health); perceived knowledge of risk-reduction strategies (i.e., subjective knowledge about how to reduce the likelihood of cardiovascular disease); and interest in risk modification (i.e., interest in changing risk-factor habits) by socioeconomic status using level of education. The study population included 2,455 women and men 25-74 years of age from three population-based cross-sectional surveys in two northern California cities. We found significant differentials in baseline knowledge that widened over the 10-year study period, resulting in larger disparities across educational groups at the final survey in 1990 (P < .05). From 1980 to 1990, individuals with < 12 years of education experienced only slight improvement in their knowledge of cardiovascular risk factors (mean summary score of 4.4 increasing to 5.5, based on a 17-item questionnaire of risk factors); those with > or = 16 years of education experienced twice as much improvement (mean of 8.4 increasing to 11.1) (P < .05). There were similar time-effect disparities in knowledge of risk-reduction strategies (P < .05). In contrast, interest in risk modification was high for all educational groups and remained uniform across time. The continuing and widening disparity in knowledge between socioeconomic groups suggests the need for policymakers to reform existing cardiovascular risk-reduction education campaigns.

Adult↗