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Biomedical subjects

L W Smith

Publications and source records attributed to L W Smith.

At least 37 records · Page 2Linked to original sources
PubMed1990

Angiotrophic lymphoma. Presentation in uterine vessels with cytogenetic studies.

An unusual case of angiotrophic lymphoma diagnosed initially in the uterus is described. Immunohistochemical studies documented the intravascular tumor cells in the myometrium to be of B lymphocytic origin. The patient's bone marrow was hypercellular, and cytogenetic studies of the aspirate revealed a subpopulation of cells with multiple clonal chromosomal abnormalities. To our knowledge, this is the first case to document abnormal cytogenetic findings in this uncommon malignancy.

B-Lymphocytes↗
PubMed1990

Avoidant coping predicts psychological disturbance in the elderly.

In a prospective study of 81 independently living elderly persons, information on coping strategy in response to a stressful life event was used in a canonical analysis to examine the relationship between coping factors and health status measures. A canonical correlation of .53 (28% of variance) indicated that those who responded to stressful life events with self-blame, wishful thinking, and avoidance tended to be more symptomatic 4 months later. In a regression analysis, avoidant coping significantly contributed to the prediction of psychological disturbance at the time of the second interview (R2 = .22, p less than .05). Coping strategy, however, did not significantly contribute to the prediction of physical health status during the interval examined. These results are generally consistent with the notion that coping strategies modulate the influence of life events on health and well-being but underscore the possibility that such relationships may differ depending on whether physical or psychological health status is being predicted.

Adaptation, Psychological↗
PubMed1989

A shortened MMPI useful for psychiatric screening of the non-institutionalized elderly.

We compared the reliability of the Faschingbauer Abbreviated MMPI (the FAM) to the standard MMPI with a sample of non-institutionalized, independently living elderly individuals. FAM items were extracted from the standard MMPIs of 83 middle-class men and women with a mean age of 74 years. Results indicate that the FAM is correlated highly with the MMPI. Although statistically significant differences were found between the FAM and MMPI forms on some scales, 77% of the profile pairs were judged to satisfy interpretive reliability criteria, and for the profiles that were rejected the FAM was not found to overestimate or underestimate any MMPI scale systematically. The potential value of the FAM as a screening device for elderly individuals who are living in the community is addressed.

Adaptation, Psychological↗
PubMed1989

Abnormal alveolar epithelial repair associated with failure of resolution in experimental streptococcal pneumonia.

We describe an experimental model in Wistar rats of non-resolving bronchopneumonia evoked by Streptococcus pneumoniae type 25. In contrast to a model of resolving streptococcal pneumonia that we have previously described, morphological studies reveal that in this model, there is significant early damage to type 1 pneumocytes which progresses to necrosis, leaving isolated areas of denuded alveolar basement membrane. Furthermore, there is accompanying degeneration and necrosis of a proportion of the type 2 pneumocytes, and alveolar epithelial repair by proliferation and differentiation of these cells appears to be retarded. Isolated, hypertrophic, and hyperplastic foci of type 2 pneumocytes persist as the acute inflammatory response subsides, and organization progresses with proliferation and emigration of fibroblasts into the lumina of alveoli and terminal bronchioles. The resultant lesion is morphologically indistinguishable from bronchiolitis obliterans organizing pneumonia. We hypothesize that the abnormal outcome in this model of pneumonia is a consequence of the failure of proliferating type 2 pneumocytes to transform into type 1 pneumocytes and thus maintain the integrity of the alveolar epithelial surface.

Animals↗
PubMed1989

Postcardiotomy delirium: conclusions after 25 years?

Although postcardiotomy delirium has been studied widely, there are few data about the current prevalence, compared to that reported in the late 1960s. There have been few efforts to replicate early observations. The authors review the literature using meta-analysis to combine the results of 44 studies. They examined the relationships between postcardiotomy delirium and 28 hypothesized risk variables. The prevalence of postcardiotomy delirium has remained fairly constant over time at 32%. There was no difference in the total prevalence of postcardiotomy delirium reported in studies that used interviews versus chart reviews. Sex, previous psychiatric illness, intelligence, and time on bypass failed to correlate with postcardiotomy delirium, and age correlated with it only slightly. Correlation coefficients of more than 0.30 were found only for noncongenital heart disease and postoperative EEG abnormality. Preoperative psychiatric intervention had the highest correlation with postcardiotomy delirium (r = -0.60).

Cardiac Surgical Procedures↗
PubMed1989

A review of the use of intrinsically 14C and rare earth-labeled neutral detergent fiber to estimate particle digestion and passage.

Methodology that allows simultaneous measurement of dynamic events affecting NDF digestion in passage from the rumen should improve our understanding of factors influencing intake and digestion. Ideally, particle flow is measured with a marker indelibly attached to or intrinsically part of the feed. If flow measurements are to reflect physiological conditions, marked and unmarked feed must be digested and passed with identical fractional rates. Application of 14C-labeled plant fiber to the study of ruminal dynamics has been slow because of expense and difficulty in producing 14C-labeled plant material. Recently, alfalfa was intrinsically labeled with 14C under field conditions to produce plant material similar in composition to unlabeled material. Carbon-14 specific activity was similar in all particle sizes, and in indigestible and digestible NDF. Greater concentrations of ytterbium (Yb) were associated with smaller vs larger particles. Larger differences in turnover rates among animals than differences attributable to treatments force comparisons of markers to be made within animal or with in vitro systems. The uncertainty about how extrinsic markers respond under various environments resulting from interaction of feed properties and gut function, and the high error inherent in measuring dynamic systems, raise serious questions on the interpretability of results. Advantages of 14C-labeled NDF over other markers include simultaneous measurements of particle breakdown, digestion and passage rates as well as the potential to study microbial attachment, VFA, CO2 and CH4 production and rate of incorporation of labeled metabolites into tissues.

Animals↗
PubMed1988

Inotropic sensitivity to beta-adrenergic stimulation in early sepsis.

In early sepsis, maintenance of in vivo cardiovascular performance is at least partly dependent on sympathetic support to hearts with intrinsic contractile defects. Yet prolonged sympathetic stimulation, as occurs in sepsis, would be expected to alter the heart's ability to respond to this stimulation. We have investigated myocardial inotropic sensitivity to beta-adrenergic stimulation in a model of sepsis in which animals, at the time studied, exhibited bacteremia, normal arterial blood pressure and cardiac output, elevated heart rate, and elevated plasma catecholamines. Intrinsic myocardial contractile function, as assessed by the maximal rate of left ventricular pressure development (LV dP/dtmax) in an isovolumically contracting heart preparation, was significantly depressed in septic animals. To determine whether hearts from septic animals could respond normally to beta-adrenergic stimulation, we studied inotropic response to a bolus of isoproterenol in these isolated hearts. With maximal isoproterenol stimulation, hearts from septic animals were able to attain the same dP/dtmax as were hearts from control animals. With lower levels of isoproterenol, there was also no difference in inotropic indexes between the two groups when response was expressed as a percent of the maximal increase in dP/dtmax achieved with isoproterenol. These results suggest that in early sepsis, despite intrinsic myocardial contractile dysfunction, the ability of the heart to modulate its inotropic state in response in beta-adrenergic stimulation is intact.

Animals↗
PubMed1988

Acute and repeated dose inhalation toxicity of para-nitrophenol sodium salt in rats.

Para-Nitrophenol Sodium Salt (PNSP) has relatively low acute inhalation toxicity; the 4-hr Approximate Lethal Concentration in rats is greater than 4.7 mg/l. One subacute study was conducted at 0, 0.34 and 2.47 mg PNSP/l for ten 6-hr exposures. Darker urine, proteinuria and elevated creatinine and SGOT were seen after exposure and were still evident after 14 days recovery. Methemoglobinemia also was seen and was reversible at 0.34 mg/l after 14 days. In addition, exposure to 2.47 mg/l caused elevated erythrocytes, hemoglobin and hematocrit. A second subacute study at 0.03 and 0.13 mg PNSP/l showed reversible methemoglobinemia only at 0.13 mg/l. The repeated dose no-observable effect level was 0.03 mg/l. No compound-related pathologic changes were noted in any of the studies.

Administration, Inhalation↗
PubMed1988

Feeding and management of dairy heifers for optimal lifetime productivity.

A total of 433 Holstein heifer calves were fed two different energy amounts from 6 wk of age to breeding weight to determine the effect of early nutrition and age at first calving on lifetime performance. A control group of 182 heifers was fed according to the Beltsville growth standard. A second group of 251 heifers was accelerated in growth by providing more energy during early development. Both groups of heifers were bred at a minimum weight of 340 kg. Average ages at first calving for control and accelerated heifers were 24.6 mo and 22.2 mo with corresponding 305-d first lactation unadjusted milk production values of 6985 and 6729 kg and unadjusted milk fat yields of 222 and 216 kg. Average 305-d milk production values through subsequent lactations for control and accelerated animals, were lactation 2, 7790, 7842 kg; lactation 3, 8200, 8330 kg; lactation 4, 9481, 9134 kg; lactation 5, 9865, 9588 kg; lactation 6, 9515, 10,108; lactation 7, 9661, 10,112. Average total milk yields over five lactations were 42,321 and 41,623 kg. Percentages of cows remaining in the herd after five lactations were 19 and 18 for control and accelerated animals. Reproductive problems, mastitis, and deaths accounted for 70% of cows leaving the herd and did not differ between treatment groups.

Animal Husbandry↗
PubMed1987

Physician marketing in the restructured medical services field.

Since the Supreme Court's ruling that removed barriers to professional advertising, one profession after another has changed radically. Restructuring has brought unparalleled marketing opportunities to professionals, many of whom are confused and even discouraged by the changes. Physicians are cautioned against "jumping onto the bandwagon" of professional advertising. They are encouraged to develop an overall marketing plan, with concrete business goals and specific marketing applications.

Advertising↗
PubMed1987

Myocardial dysfunction in sepsis.

A synthesis of the postulated sequence of events for development of the inappropriate response of the myocardium to a demand for increased cardiac index is schematically represented in Fig. 10. In sepsis, bacteremia and/or the release of endotoxin activate the macrophages which release a spectrum of mediators. Some of these mediators (and possibly also endotoxin itself) have a negative influence on myocardial contractile function either directly and/or through altering cellular calcium flux. This results in impaired myocardial function manifested initially by decreased stroke volume. Subsequently, stroke volume will be either partially or completely restored to normal through the action of circulating catecholamines, the concentration of which is markedly elevated due to the presence of endotoxin and/or macrophage-produced mediators. Endotoxin and/or these mediators also act on the SA node increasing its sensitivity to beta-adrenergic stimulation. This will result in elevated heart rates. The latter, combined with the restored stroke volume, will yield an increased cardiac index which is the hallmark of the hyperdynamic phase of sepsis. In the cecal ligation and puncture model of sepsis, where cardiac index is maintained at the original level, the partially restored stroke volume and the elevated heart rate will combine to maintain cardiac index. Although this mechanism of increasing cardiac index through tachycardia is not energy efficient, the myocardium is able to cope with these changes and also to maintain its high energy phosphate concentrations, since the utilization of the three major myocardial substrates (fatty acids, lactate and glucose) is not affected by sepsis. Although this putative sequence of events is consistent with the observed experimental findings, further work is needed to substantiate its applicability to the etiology of myocardial dysfunction in man during sepsis.

Animals↗
PubMed1986

Cardiac function and chronotropic sensitivity to beta-adrenergic stimulation in sepsis.

An organism's cardiovascular response to sepsis is at least partly dependent on hormonal and neural modulation of myocardial function. We have investigated both intrinsic myocardial performance and one aspect of myocardial sensitivity to beta-adrenergic stimulation in a model of sepsis in which animals, at the time studied, exhibited bacteremia, normal arterial blood pressure and cardiac output, elevated heart rate, and elevated plasma catecholamines. Intrinsic myocardial contractile function, studied with the isolated, perfused working heart preparation, was depressed over a range of preloads in septic animals, whereas heart rate was elevated. To determine whether hearts from septic animals could respond normally to beta-adrenergic stimulation, we studied chronotropic responses to isoproterenol in both Langendorff perfused hearts and in isolated right atria. In langendorff perfused hearts from septic animals, basal rates were significantly increased and lower concentrations of isoproterenol elicited greater increases in heart rate. In isolated right atria from septic animals, basal rates were also elevated and the EC50 for the chronotropic response to isoproterenol was significantly less than in atria from control animals. The maximal heart rate response to isoproterenol was not significantly different from control. These results indicate that in sepsis, despite apparently adequate in vivo cardiac performance, intrinsic myocardial function is depressed, but chronotropic sensitivity to beta-adrenergic stimulation is increased.

Animals↗
PubMed1983

Data base management system for tracking occupational health.

An Occupational Health Information System (OHIS), a data base management system for tracking occupational health, has been developed. A primary feature is its ability to correlate employee workplace environment with health. Hardware implementation of OHIS is on a minicomputer with application programs written in ANSI standard MUMPS language. OHIS integrates personnel, medical and industrial hygiene/toxicology information into one data base. The personnel module is comprised of demographic information collected and updated by the personnel department. The medical module utilizes an interactive video display terminal (VDT)-driven questionnaire and multiphasic testing subsystems which are accessed selectively by authorized users. The backbone of OHIS is a parameter dictionary of all possible data elements. A final medical report includes a medical history summary, physical findings and X-ray interpretation, highlighted and normal test findings, computer interpretations, and a final one-page summary of problem and health-risk information. Information characterizing the workplace environment is captured and reported by the questionnaire subsystem. This questionnaire is designed to define: 1) monitoring conditions, 2) sample analysis, 3) measurement results, and 4) personal protective equipment used. These data provide a means of assigning environmental exposure measurements to appropriate employees.

Adult↗
PubMed1982

Short-term inhalation toxicity of perfluoroisobutylene.

Perfluoroisobutylene (PFIB) is a highly toxic, colorless gas. The 4-hour Approximate Lethal Concentration in male rats is 0.5 ppm (v/v). The median lethal concentration (LC50) was calculated for groups of 10 male Crl:CD rats, exposed, nose-only, for either 0.25, 0.50, 1, 2, 5, or 10 minutes to various concentrations of PFIB. Atmospheric concentrations of PFIB were determined by gas chromatography (electron capture detector). No mortalities or signs of respiratory irritation were seen during exposure. Weight loss and respiratory impairment were evident up to 48 hours post-exposure. Affected rats either died with gross pathological signs of pulmonary congestion or recovered with no apparent residual effects. The 0.25-minute LC50 was 361 ppm (321--415 ppm, 95% Confidence Limits); the 10-minute LC50 was 17 ppm (15--19 ppm, 95% Confidence Limits). The steep slope of the concentration-mortality curve at each time interval reflected the narrow range of concentrations that produced mortality (LC1-LC99). In addition, a "Concentration x Time = Constant" relationship was apparent from 0.25 to 10 minutes.

Animals↗