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Biomedical subjects

J E Williams

Publications and source records attributed to J E Williams.

At least 37 records · Page 2Linked to original sources
PubMed2001

Soluble scute proteins of healthy and ill desert tortoises (Gopherus agassizii).

OBJECTIVES: To characterize protein composition of shell scute of desert tortoises and to determine whether detectable differences could be used to identify healthy tortoises from tortoises with certain illnesses. ANIMALS: 20 desert tortoises. PROCEDURES: Complete postmortem examinations were performed on all tortoises. Plastron scute proteins were solubilized, scute proteins were separated by use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and proteins were analyzed, using densitometry. Two-dimensional immobilized pH gradient-PAGE (2D IPG-PAGE) and immunoblot analysis, using polyclonal antisera to chicken-feather beta keratin and to alligator-scale beta keratin, were conducted on representative samples. The 14-kd proteins were analyzed for amino acid composition. RESULTS: The SDS-PAGE and densitometry revealed 7 distinct bands, each with a mean relative protein concentration of > 1 %, ranging from 8 to 47 kd, and a major protein component of approximately 14 kd that constituted up to 75% of the scute protein. The 2D IPG-PAGE revealed additional distinct 62- and 68-kd protein bands. On immunoblot analysis, the 14-, 32-, and 45-kd proteins reacted with both antisera. The 14-kd proteins had an amino acid composition similar to that of chicken beta keratins. There was a substantial difference in the percentage of the major 14-kd proteins from scute of ill tortoises with normal appearing shells, compared with 14-kd proteins of healthy tortoises. CONCLUSIONS AND CLINICAL RELEVANCE: The major protein components of shell scute of desert tortoises have amino acid composition and antigenic features of beta keratins. Scute protein composition may be altered in tortoises with certain systemic illnesses.

Animal Diseases↗
PubMed2001

Influence of undegraded intake protein on reproductive performance of primiparous beef heifers maintained on stockpiled fescue pasture.

The objectives of this study were to evaluate the effects of pre- and postpartum undegraded intake protein (UIP) supplementation on body condition score (BCS), BW, calf weight, milk production, serum IGF-I concentrations, and postpartum interval in primiparous beef heifers (n = 44). Heifers were maintained on endophyte-free stockpiled tall fescue (11.7% CP, 38% ADF) and individually fed supplement daily beginning 60 d prepartum. Pre- and postpartum supplements provided 19.3% CP, 83.4% TDN (UIP); 14.1% CP, 84.1% TDN (Control); 21.5% CP, 81.5% TDN (UIP); and 14.6% CP, 81.4% TDN (Control); respectively. Blood meal (146 g/d) was the source of UIP. Six heifers were removed from the study due to calf loss unrelated to treatment; therefore, postpartum measurements are based on 19 animals per treatment. Statistical analyses using ANOVA and a split-plot design revealed no effects of treatment (P > 0.2) on BCS, BW, calf weight, milk production, or postpartum interval. There tended to be a treatment x time interaction on BCS (P < 0.09) with UIP heifers having higher BCS than Control at wk 5, 7, and 9 postpartum. There was a treatment x time interaction on serum IGF-I (P < 0.06) during the first 35 d postpartum. In UIP heifers, serum IGF-I was greater at calving compared with Control heifers (117.5 vs 92.4 ng/mL, respectively); however, these differences were not related to changes in BCS or BW. Although serum IGF-I concentrations were increased at calving in heifers receiving UIP, there were no treatment effects on postpartum interval (P > 0.7). During the first 30 d postpartum, IGF-I differed (P < 0.01) among heifers with postpartum intervals defined as short, < 50 d (128.9 ng/mL); medium, 51 to 65 d (115.2 ng/mL); and long, 66 to 130 d (52.9 ng/mL). When analyzed as a regression, a 1 ng/mL increase in IGF-I (UIP and Control heifers) at calving (P < 0.05) and throughout the postpartum period (P < 0.01) corresponded to a decrease in postpartum interval of 0.13 d. Based on the results of this study, the inclusion of UIP in diets for primiparous heifers and its effects on postpartum interval warrant further evaluation.

Animal Feed↗
PubMed2001

Review of antiviral and immunomodulating properties of plants of the Peruvian rainforest with a particular emphasis on Una de Gato and Sangre de Grado.

Viral diseases, including emerging and chronic viruses, are an increasing worldwide health concern. As a consequence, the discovery of new antiviral agents from plants has assumed more urgency than in the past. A number of native Amazonian medicines of plant origin are known to have antimicrobial and anti-inflammatory activity, although only a few have been studied for their antiviral properties and immunomodulating effects. Those most studied include: Sangre de Grado (drago) (Croton lechleri) in the Euphorbiaceae family and Una de Gato (Uncaria tomentosa) in the Rubiaceae family. This article reviews the chemical composition, pharmacological properties, state of current research, clinical use, and potential antiviral and immunomodulating activity of these and other plants from the Peruvian Amazon.

Antibody Formation↗
PubMed2000

Anger proneness predicts coronary heart disease risk: prospective analysis from the atherosclerosis risk in communities (ARIC) study.

BACKGROUND: Increased research attention is being paid to the negative impact of anger on coronary heart disease (CHD). METHODS AND RESULTS: This study examined prospectively the association between trait anger and the risk of combined CHD (acute myocardial infarction [MI]/fatal CHD, silent MI, or cardiac revascularization procedures) and of "hard" events (acute MI/fatal CHD). Participants were 12 986 black and white men and women enrolled in the Atherosclerosis Risk In Communities study. In the entire cohort, individuals with high trait anger, compared with their low anger counterparts, were at increased risk of CHD in both event categories. The multivariate-adjusted hazard ratio (HR) (95% CI) was 1.54 (95% CI 1.10 to 2.16) for combined CHD and 1.75 (95% CI 1.17 to 2.64) for "hard" events. Heterogeneity of effect was observed by hypertensive status. Among normotensive individuals, the risk of combined CHD and of "hard" events increased monotonically with increasing levels of trait anger. The multivariate-adjusted HR of CHD for high versus low anger was 2.20 (95% CI 1.36 to 3.55) and for moderate versus low anger was 1.32 (95% CI 0.94 to 1.84). For "hard" events, the multivariate-adjusted HRs were 2.69 (95% CI 1.48 to 4.90) and 1.35 (95% CI 0.87 to 2.10), respectively. No statistically significant association between trait anger and incident CHD risk was observed among hypertensive individuals. CONCLUSIONS: Proneness to anger places normotensive middle-aged men and women at significant risk for CHD morbidity and death independent of the established biological risk factors.

Aged↗
PubMed2000

Blastocystis hominis: neutral red supravital staining and its application to in vitro drug sensitivity testing.

A simple in vitro drug sensitivity testing system for Blastocystis hominis clinical isolates was developed. Application of supravital staining by neutral red allowed quantitative viability assessment. Four xenic cultures, isolated from human sources, were grown in modified monophasic Robinson's medium and tested for sensitivities to nine available drugs. Assessment was done using the cell-count method from air-dried preparations after supravital staining with neutral red. Also, the light absorbence method was evaluated. Trimethoprim, metronidazole, quinacrine, tetracycline, paromomycin, and two new antiprotozoal drugs, nitazoxanide and deacetyl-nitazoxanide, showed cytostatic or cytocidal effects on all or some Blastocystis isolates. Chloroquine and sulphamethoxazole did not demonstrate any effect at the concentrations studied.

Amebicides↗
PubMed2000

The integrity of Web-delivered experiments: can you trust the data?

Data from Web-delivered experiments conducted in browsers by remote users of PsychExperiments, a public on-line psychology laboratory, reveal experiment effects that mirror lab-based findings, even for experiments that require nearly millisecond accuracy of displays and responses. Textbook results are obtained not just for within-subjects effects, but for between-subjects effects as well. These results suggest that existing technology is adequate to permit Web delivery of many cognitive and social psychological experiments and that the added noise created by having participants in different settings using different computers is easily compensated for by the sample sizes achievable with Web delivery.

Bias↗
PubMed2000

Effect of dietary energy on milk production and metabolic hormones in thin, primiparous beef heifers.

Thirty-six primiparous heifers were used to determine the effect of dietary energy on postpartum interval, milk production, serum concentrations of insulin, insulin-like growth factor I (IGF-I), growth hormone, and cerebrospinal fluid (CSF) concentrations of neuropeptide-Y (NPY). Low-quality hay was fed during the last trimester of pregnancy to achieve suboptimal calving weight (370 +/- 5 kg) and condition score (4.0 +/- .1). After calving, cows were allotted to one of four dietary treatments that differed in metabolizable energy. Experimental diets were fed at 2.5% of shrunk body weight and formulated to provide 1.8 (low), 2.1 (maintenance), 2.4 (maintenance high), or 2.7 (high) Mcal of ME/kg DM. Daily milk production was estimated at approximately 30, 60, and 90 d postpartum. Condition score change and weight change were defined as change from calving to d 90 postpartum. As energy intake increased, condition score change (P < .001), IGF-I (P < .001) and insulin (P < .01) increased and postpartum interval decreased (P = .04). No relationship existed between postpartum interval and CSF concentration of NPY (P > .1). Condition score change was positively associated with IGF-I and insulin (r = .71, P < .001; r = .38, P = .02, respectively) and negatively associated with GH (r = -.67, P < .001). Weight change and serum concentrations of GH did not differ (P > .10) among treatments. Increasing dietary energy intake was associated with a curvilinear increase in milk yield (P = .04) and percentage milk fat (P = .03) and a linear increase (P = .04) in energy available for milk production. Greater milk yield at d 30 was associated with a longer postpartum interval (r = .34, P < .05). In conclusion, a greater proportion of net energy is partitioned to maternal tissue realimentation when cows receive high compared to low-, maintenance-, or moderate-energy diets.

Animal Feed↗
PubMed1999

Racial disparities in CHD mortality from 1968-1992 in the state economic areas surrounding the ARIC study communities. Atherosclerosis Risk in Communities.

PURPOSE: This study examined racial variations in CHD (coronary heart disease) mortality rates (1968-1992) of residents aged 35-84 in the state economic areas (SEAs) surrounding the ARIC (Atherosclerosis Risk in Communities) study. The quarter century of CHD mortality rates are discussed in relation to racial and gender differences in baseline risk factors measured in the ARIC cohort and to the incidence of hospitalized myocardial infarction and case fatality rates obtained from the community surveillance component of the ARIC study between 1987 and 1994, inclusive. METHODS: Five-year average annual, gender- and age-specific CHD mortality rates were compared across race groups, based on National Vital Statistics data for state economic areas. RESULTS: Five-year average annual CHD mortality declined 2.6% for white men and women and 1.6% and 2.2% for black men and women, respectively. The black-white mortality rate ratio increased over time for men and women. The black-white mortality age crossover (higher black than white mortality in young men, lower black than white mortality at older ages) had disappeared by the end of the observation. CHD mortality was markedly greater in black than white women at all ages and time periods. The black disadvantage in CHD mortality was increasingly greater in the ARIC SEAs than in the United States as a whole. CONCLUSIONS: Persistent and increasing racial disparities in CHD mortality occurred in the ARIC SEAs concurrently with racial differences in risk factors, the incidence of myocardial infarction, and case fatality rates.

Adult↗
PubMed1999

Measured energy expenditure of tube-fed patients with severe neurodevelopmental disabilities.

OBJECTIVE: To determine measured resting energy expenditure (REE) of nonambulatory tube-fed patients with severe neurological neurodevelopmental disabilities. METHODS: Twenty patients were prospectively studied. Only steady state indirect calorimetry measurements were taken. All measurements were conducted using a canopy system. Nutritional needs were met entirely by enteral feedings via a permanent ostomy. RESULTS: REE was widely distributed from 16 kcals/kg/day to 39 kcals/kg/day. The mean REE (888+/-176 kcals/day) of the patients was significantly (p<0.01) lower than predicted as estimated by the Harris-Benedict equations (1081+/-155 kcals/day) and World Health Organization equations (1194+/-167 kcals/day). Fat-free mass (FFM) was the best parameter for predicting REE. Two predictive equations were developed that are not significantly biased and more precise (< or =15% error) than conventional predictive formulas. CONCLUSION: Conventional formulas for estimating energy expenditure are inaccurate and generally overestimate measured energy expenditure of nonambulatory patients with severe developmental disabilities.

Adolescent↗
PubMed1999

Self-complexity and the persistence of depression.

Self-complexity, a measure of the structure of cognition involving the self, was used to predict the persistence of depression in patients diagnosed with major depression. Self-descriptions offered by depressed patients were analyzed using a clustering algorithm to model cognitive structure. Indices of positive and negative self-complexity, derived from the resulting models, were used to predict depressive symptomatology 9 months after the onset of a major depression. Negative self-complexity uniquely predicted subsequent levels of depression even after the effects of initial levels of depression, self-evaluation, and dysfunctional attitudes were statistically removed. Highly complex negative self-representation appears to be associated with poor recovery from a major depressive episode. Future studies examining the relationship between cognition and psychopathology should investigate, in addition to its content, the formal and structural properties of cognition.

Adult↗
PubMed1999

Neuromechanical interaction in human snoring and upper airway obstruction.

The fact that snoring and obstructive apnea only occur during sleep means that effective neuromuscular functioning of the upper airway during sleep is vital for the maintenance of unimpeded breathing. Recent clinical studies in humans have obtained evidence demonstrating that upper airway neural receptors sense the negative pressure generated by inspiration and "trigger," with a certain delay, reflex muscle activation to sustain the airway that might otherwise collapse. These findings have enabled us to propose a model in which the mechanics is coupled to the neuromuscular physiology through the generation of reflex wall stiffening proportional to the retarded fluid pressure. Preliminary results on this model exhibit three kinds of behavior typical of unimpeded breathing, snoring, and obstructive sleep apnea, respectively. We suggest that the increased latency of the reflex muscle activation in sleep, together with the reduced strength of the reflex, have important clinical consequences.

Airway Obstruction↗
PubMed1999

Effects of short- or long-term infusions of acetate or propionate on luteinizing hormone, insulin, and metabolite concentrations in beef heifers.

Two trials were conducted to evaluate the effects of short- (Trial 1) or long-term (Trial 2) intraruminal isocaloric infusions of acetate or propionate on secretion of LH, insulin, and selected metabolites in short- or long-term energy-restricted beef heifers. In Trial 1, 16 Angus heifers were assigned on d 6 to 12 of a synchronized estrous cycle (estrus = d 0) to a body weight-maintenance (BWM; n = 4) or an energy-restricted, body weight-loss (BWL; n = 12) treatment. On d 12 of a synchronized estrous cycle, heifers received PGF2alpha to synchronize estrus, and 12 h later BWL heifers received intraruminal, isocaloric infusions of acetate, propionate, or vehicle for 6 h and BWM heifers received vehicle concurrently. Mean plasma LH and LH pulse frequencies and amplitudes were not affected by treatment (P > .05). In contrast, infusion of propionate increased plasma insulin (P < .05) and reduced plasma concentration of NEFA (P < .05). In Trial 2, six ovariectomized Angus heifers were energy-restricted for 30 d. On d 14 and 26 of restriction, heifers began receiving intraruminal isocaloric infusions of acetate or propionate for 96 h in a switchback approach. Intraruminal infusions of vehicle for 6 h preceded infusions of acetate or propionate. Jugular blood was collected at 12-min intervals during infusions of vehicle and during the last 6 h of infusion of acetate or propionate. Mean concentration of LH and amplitude of pulses of LH were lower during acetate vs propionate or vehicle infusion (P < .05). Infusion of propionate increased insulin relative to acetate or vehicle infusion (P < .05). Plasma NEFA were reduced by infusion of propionate (P < .05) and increased by infusion of acetate (P < .05).

3-Hydroxybutyric Acid↗
PubMed1999

Undergraduate labs and computers: the case for PsychExps.

PsychExps (http:/(/)www.olemiss.edu/PsychExps) is an interactive on-line psychology laboratory designed to facilitate teaching and conducting research over the Internet. With the increased use of the Web among students and the development of technology enabling the deployment of experiments via the Internet, a laboratory such as PsychExps appears to offer numerous advantages over the solely classroom-based laboratory. As part of the development of PsychExps, a survey was conducted, to assess the utility of this novel approach to the traditional computer-based psychology laboratory classes. Responses generally indicate interest in and a need for cost-effective resources such as an Internet-based laboratory. In addition, PsychExps offers several advantages over the mostly pedagogical and demonstration-based psychology sites on the Internet.

Computers↗
PubMed1998

Real time measurement of stimulated dopamine release in the conscious rat using fast cyclic voltammetry: dopamine release is not observed during intracranial self stimulation.

Fast cyclic voltammetry (FCV) was used to measure real time release of electrically stimulated endogenous dopamine in the nucleus accumbens (NAc) of conscious freely moving rats for up to 17 days. The method of electrode construction, implantation, electrical stimulation and recording of changes of extracellular dopamine concentration in the conscious rat are described. Rats trained on a continuous reinforcement schedule to perform intracranial self stimulation (ICSS) were implanted with electrodes for FCV. During ICSS, no faradaic signal was observed at an electrode implanted in the NAc. Decreasing the intensity of the stimulating current abolished ICSS, increasing the stimulating current disrupted ICSS. Operator delivered electrical stimulations using currents greater than those needed for ICSS yielded dopamine signals. It is concluded that during ICSS, sufficient dopamine does not reach the extracellular fluid space to yield a faradaic signal detectable by FCV.

Animals↗