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Biomedical subjects

L W Smith

Publications and source records attributed to L W Smith.

At least 19 recordsLinked to original sources
PubMed1997

Application of inter simple sequence repeat (ISSR) markers to plant genetics.

Microsatellites or simple sequence repeats (SSRs) are ubiquitous in eukaryotic genomes. Single-locus SSR markers have been developed for a number of species, although there is a major bottleneck in developing SSR markers whereby flanking sequences must be known to design 5'-anchors for polymerase chain reaction (PCR) primers. Inter SSR (ISSR) fingerprinting was developed such that no sequence knowledge was required. Primers based on a repeat sequence, such as (CA)n, can be made with a degenerate 3'-anchor, such as (CA)8RG or (AGC)6TY. The resultant PCR reaction amplifies the sequence between two SSRs, yielding a multilocus marker system useful for fingerprinting, diversity analysis and genome mapping. PCR products are radiolabelled with 32P or 33P via end-labelling or PCR incorporation, and separated on a polyacrylamide sequencing gel prior to autoradiographic visualisation. A typical reaction yields 20-100 bands per lane depending on the species and primer. We have used ISSR fingerprinting in a number of plant species, and report here some results on two important tropical species, sorghum and banana. Previous investigators have demonstrated that ISSR analysis usually detects a higher level of polymorphism than that detected with restriction fragment length polymorphism (RFLP) or random amplified polymorphic DNA (RAPD) analyses. Our data indicate that this is not a result of greater polymorphism genetically, but rather technical reasons related to the detection methodology used for ISSR analysis.

Autoradiography↗
PubMed1993

Psychometric evaluation of pharmacology calculation test for hospital staff nurses.

Based on our evaluation, we believe this newly developed test is a reliable and valid instrument for measuring nurses' competence in performing pharmacological calculations. The overall conclusion that this test is reliable and valid is strengthened by the use of various different measures of both reliability and validity. Following completion of this evaluation study, we began to use this test with all newly hired nursing staff. We arbitrarily chose a cut-off score of 80 percent as the passing score. Individuals who could not pass on their first attempt were offered remediation and then allowed a second attempt. During the first three months of use, we tested 25 newly hired nurses. Of those, 20 were able to pass the pharmacological calculations test on their first or second attempt, with a mean score of 88.7. The score on the second attempt of the five who failed (all LPNs) was 53.0. These individuals were not allowed to actually work as nurses at our hospital. We have subsequently changed the policy to allow three attempts, using the three parallel versions of the test. Remediation is offered after the second failed attempt. This approach has reduced the time needed by the education department to remediate, but meets nursing managers' desire and need to help those who can succeed and become competent members of our staff. The test has not been in use at our institution for over two years and is administered to all nurses who provide patient care in our institution (including agency/travel nurses). It has been generally well received and we area convinced that it can accurately measure nurses' pharmacological calculation competence.

Clinical Competence↗
PubMed1992

Symptoms of illness in late adulthood are related to childhood social deprivation and misfortune in men but not in women.

Experiencing adverse life events during childhood may increase vulnerability to physical illnesses and psychological disorders during adulthood. We developed an Early Life Events Questionnaire (ELEQ) with 12 scales and administered it to 92 relatively healthy elderly individuals (29 men and 63 women). A canonical-correlation analysis of the 12 ELEQ scales and physical and psychological symptoms revealed a significant canonical correlation. The results indicate that those who grew up in a family with a harsh climate and whose affiliation needs were not met tended to have more psychological and physical symptoms in old age. Regression analysis revealed that, in men, early life events accounted for 42% of the variance in physical symptoms and 39% in psychological symptoms. No significant relationship, however, was found between ELEQ scales and health outcomes in women. These results suggest that women may be less vulnerable than men to the adverse health consequences of childhood deprivation and other misfortunes.

Age Factors↗
PubMed1991

Primary culture of adult mouse lung fibroblasts in serum-free medium: responses to growth factors.

We report a completely serum-free system for primary culture of fibroblasts from explants of adult mouse lung tissue which permits bioassays for cytokine activity to be performed using unselected populations of cells at low passage number, without interference by serum binding proteins or interacting growth factors. Cultures were established on collagen-coated surfaces in medium MCDB 201 containing albumin, transferrin, epidermal growth factor, lipids, prostaglandin E1, vitamin E, and reducing agents. The cells were morphologically and ultrastructurally typical of fibroblasts in culture and demonstrated expression of vimentin and induction of expression of desmin in culture. Proliferation of the cells was reproducible between different primary cultures and was growth factor dependent. Both cycling and growth-arrested cells exhibited increased DNA synthesis when stimulated with epidermal growth factor, platelet-derived growth factor, or basic fibroblast growth factor, which functioned as complete mitogens, but did not respond to insulin, tumor necrosis factor or interleukin-1 beta. Maximal induction of DNA synthesis by epidermal growth factor required the continued presence of the mitogen in the culture medium. These results cannot be satisfactorily explained by the competence-progression model of responses to mitogenic stimuli but support and extend the findings of other studies using diploid fibroblasts.

Animals↗
PubMed1990

Chromosome abnormalities in human epithelial ovarian malignancies.

Karyotypic analysis of tumor specimens from 29 patients with untreated epithelial ovarian carcinoma was performed at the University of Kentucky Medical Center. Twenty-three of the twenty-nine tumors had adequate cells for analysis. Seventeen of these tumors exhibited chromosome abnormalities. Chromosome alterations were complex, with an average of seven different abnormal chromosomal patterns per tumor (range 2-14). Chromosomes 1 and 11 were the most commonly involved, being abnormal in 89 and 83% of tumors, respectively. Chromosomes 3 and 7 were also frequently abnormal. In contrast to invasive tumors, alterations in chromosomes 1 and 11 were not seen in the two tumors of borderline malignant potential. Evidence for DNA amplification of IGF2, Ha-ras-1, and c-ets was not observed. Amplification of the c-erbB-2 oncogene was present in two tumors. These findings indicate that multiple karyotypic abnormalities occur in untreated epithelial ovarian malignancies, with chromosomes 1 and 11 being the most frequently abnormal. These data also suggest that alterations of these chromosomes may be associated with the biologically aggressive behavior of frankly invasive ovarian tumors.

Adult↗
PubMed1990

Internal vs. external determinants of coping responses to stressful life-events in the elderly.

Coping appears to function in the relationship between stressful life-events and health. Factors that may influence an individual's use of a particular coping strategy, however, are not well understood. Coping consistency within individuals and across situations was examined in a longitudinal study of 74 independently living elderly persons, as were the effects of the type of event experienced, appraisal of its degree of threat, and demographic variables on coping behaviour. Correlational analyses indicated that coping responses were more a function of event type than of an individual's consistent style. A number of distinct life-events were associated with particular types of coping responses. The degree of threat, one's expectation of the changeability of an event, and one's appraisal of possible courses of action were also correlated with specific coping behaviours. Age was negatively correlated with problem-focused coping and total number of coping responses. This study suggests that the type of stressful event an individual experiences may be a more important general determinant of one's coping response than is one's overriding propensity to cope in a particular way.

Adaptation, Psychological↗
PubMed1990

Particle size reduction during initial mastication of forages by dairy cattle.

Four experiments were conducted with dairy cattle to determine the effects of initial feed particle size and moisture content on particle size of ingested masticates. Three mature Holstein cows were used in either latin square or Youden square designs. Samples of masticated and ingested boli were collected at the cardiac opening through a ruminal fistula between 0 and 5, 5 and 10 and 10 and 15 min after meal initiation. In Exp. 1, masticate log mean particle sizes (LMPS) (ln microns, log normal distribution) were 3.50, 3.53 and 3.50 for corn silage, fine-chopped alfalfa haylage and coarse-chopped alfalfa haylage, respectively. In Exp. 2, boli LMPS for ground, chopped and long alfalfa hay were 3.11, 3.76 and 4.09, respectively. Boli LMPS in Exp. 3 for ground, chopped and long timothy hay were 2.93, 3.12 and 3.03, respectively. Exp. 4 compared the effect of addition of water to produce 30%, 47%, 64% and 82% DM in chopped alfalfa hay. Boli LMPS were 3.66, 3.56, 3.64 and 3.68 for the respective alfalfa hay DM contents. Feed LMPS was not reduced during mastication in Exp. 4, nor were there differences in LMPS due to time after feeding. Boli LMPS was affected by feed particle size of alfalfa hay, but there was no effect of feed particle size on masticate particle size in timothy hay. The magnitude of particle size reduction during mastication appears to be dependent on forage type and is not dependent totally on initial feed particle size and DM content of forages.

Animal Feed↗
PubMed1990

Supersensitivity and changes in the active population of beta adrenoceptors in rat right atria in early sepsis.

We have investigated the effect of sepsis induced by cecal ligation and puncture on the chronotropic actions of beta adrenoceptor agonists on isolated right atria. The present findings show that right atria obtained from rats in an early stage of sepsis were supersensitive to the chronotropic actions of the beta-agonists, isoproterenol (ISO), fenoterol (FEN) and prenalterol (PREN). The supersensitivity to the chronotropic actions of ISO and FEN was much greater than that which developed to PREN. The positive chronotropic actions of isobutylmethylxanthine and forskolin were not affected by sepsis. The receptor subtypes mediating the responses to ISO, FEN and PREN by control and septic right atria were characterized by functional assays using selective beta-1 and beta-2 antagonists. The results showed that the chronotropic response produced by all three agonists on right atria obtained from control rats were mediated by beta-1 receptors. In contrast, the chronotropic actions of ISO and FEN on atria from septic rats were mediated by what appears to be beta-2 receptors and those of PREN by beta-1 receptors.

1-Methyl-3-isobutylxanthine↗
PubMed1990

In vitro cardiac function in early sepsis.

The involvement of the myocardium in the injury resulting from bacteremia has been somewhat controversial. Recently, some investigators have suggested that the transition from an early stage of sepsis, in which the cardiovascular system is stable and mortality is relatively low, to the late or preterminal stage of sepsis is a result of cardiac dysfunction. Here, however, data are presented to show that contractile defects and loss of myocardial reserve occur even early during a septic episode, i.e., at a time when cardiac output is elevated or normal. Efforts to determine the mechanism of the cardiac dysfunction are described. These entail studies of whole heart performance under conditions of varying the calcium availability for contraction and assessment of subcellular organelle function. The data indicate that calcium dyshomeostasis may at least partially contribute to the cardiac dysfunction of sepsis. The in vivo adequacy of cardiac function probably results from the capacity of the myocardium in early sepsis to respond to catecholamine support of chronotropy and inotropy.

Animals↗