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Biomedical subjects

S L Schmidt

Publications and source records attributed to S L Schmidt.

35 records · Page 2Linked to original sources
PubMed1996

US experiences for quality assurance in Swiss health care settings.

This report illustrates the first step of a research project at the Institute of Business Research, University of Zurich, concerning quality improvement techniques in Swiss health care institutions. It endeavors to provide a forecast of further research activities. Apart from the analysis provided by the most recent follow-up on the National Demonstration Project for Quality Improvement in Health Care (NDP), this also shows the lessons learned from the perspective of the initial NDP participants. Additionally, the results are adapted for application to European circumstances for quality improvement activities in health care institutions. US experience shows that physician involvement along with a good database are key success factors for quality improvement. Strategically important processes must be selected early on for quality improvement projects. It is important to start with intensive training of process leaders instead of a broad-based training. Furthermore, the new Swiss law regarding quality assurance and its results are explained. The formation of the National Committee for Quality Assurance (NAQ) means that first-time Swiss health care providers, as well as health insurance-companies and cantonal representatives, are discussing quality measures and clinical standards on a national level.

Forecasting↗
PubMed1993

The ontogenesis of the forebrain commissures and the determination of brain asymmetries.

We have reviewed the organization and development of the interhemispheric projections through the forebrain commissures, especially those of the CC, in connection with the development of brain asymmetries. Analyzing the available data, we conclude that the developing CC plays an important role in the ontogenesis of brain asymmetries. We have extended a previous hypothesis that the rodent CC may exert a stabilizing effect over the unstable populational asymmetries of cortical size and shape, and that it participates in the developmental stabilization of lateralized motor behaviors.

Animals↗
PubMed1993

Paw preference in mice with callosal defects induced by prenatal gamma irradiation.

The development of the corpus callosum of male Swiss mice was perturbed by exposure to gamma radiation at embryonic day 16 with total doses of 2 Gy (N = 48) or 3 Gy (N = 26). At adulthood paw preference was studied in these callosal defective animals and in 93 control nonirradiated male Swiss mice. The analysis of directional laterality indicated a populational tendency for right paw use in the 2 Gy group (60%) that was markedly increased in the 3 Gy group (95%). In the 3 Gy group, directional laterality was significantly different from chance in contrast to that observed in normal controls (49%). In the three groups most mice presented a significant individual paw preference. These data are consistent with our hypothesis that the early absence of the corpus callosum disrupts the normal pattern of directional asymmetries.

Agenesis of Corpus Callosum↗
PubMed1991

The effects of total and partial callosal agenesis on the development of paw preference performance in the BALB/cCF mouse.

The relation between callosal defects and paw preference was investigated in 85 male mice of the BALB/cCF strain. Paw preference was also studied in 30 male Swiss mice. Directional laterality and magnitude of laterality devoid of directionality were evaluated independently. The study of the magnitude of paw preference showed that male BALB/cCF mice were more strongly lateralized than Swiss mice. There was no difference between BALB/cCF mice with callosal defects (abnormal group) and normal BALB/cCF mice. The analysis of directional laterality indicated a population tendency for left-paw use in BALB/cCF as compared to Swiss mice. Furthermore, the percentage of left-pawed animals in the abnormal group (78%) was significantly different from chance level, as opposed to an absence of such differences in the normal BALB/cCF and in Swiss mice. It was concluded that developmental disturbance of the corpus callosum is related to the appearance of a directional populational asymmetry in paw preference.

Agenesis of Corpus Callosum↗
PubMed1991

Disparity selective units in the superior colliculus of the opossum.

Binocular visual responses can be recorded in two regions of the superficial layers of the superior colliculus of the opossum. The direct binocular region (DBR) represents the binocular portion of the contralateral hemifield whereas the rostral pole (RP) represents the binocular portion of the ipsilateral hemifield. In the present study single units from both of these regions were tested with binocular and monocular stimulation. Most cells in both regions showed response facilitation when both eyes were simultaneously stimulated and, when tested with different binocular disparities, most cells showed broadly-tuned disparity selectivity. DBR units usually preferred disparities near zero whereas RP units had a wider range of preferred disparities, with a tendency toward positive (crossed) values. This data indicates that the superior colliculus of the opossum could provide a neural substrate for a coarse analysis of depth and also might help control vergence eye movements. The different ranges of disparity selectivity of DBR and RP are consistent with the previously reported monocular receptive-field data and suggest that DBR and RP analyze different depths of the 3-dimensional visual scene.

Animals↗
PubMed1991

The effects of total and partial callosal agenesis on the rotatory behavior of BALB/cCF mice.

We report a study on rotational behavior (free swim test) of 30 adult male mice of an inbred strain in which about 20% of the animals are born with callosal defects (the BALB/cCF strain). The experiment was designed to study the relationship between the development of the corpus callosum and the degree of lateralization in rotatory behavior. Most of the BALB/cCF mice (77%) were lateralized rotators. Although most animals with a normal callosal area presented individual asymmetry, there was no significant tendency for a populational asymmetry toward one side in this group. In contrast, 75% of the animals with abnormally small callosal areas were left rotators. These animals, therefore, presented not only individual asymmetry, but also a tendency for a populational asymmetry. It was concluded that disturbances in the development of the corpus callosum are related to the appearance of directional populational asymmetry in rotatory behavior.

Agenesis of Corpus Callosum↗
PubMed1991

Absence of population cerebral asymmetries in mice with callosal defects induced by prenatal gamma irradiation.

The development of the corpus callosum of 19 male Swiss mice was disturbed by exposure to a 60Co gamma source on embryonic day 16 with a total dose of 2 Gy (dose rate of 56 to 59 rads/min). At adulthood the animals were perfused with saline followed by formaldehyde and the cerebral hemispheres were weighed and photographed in dorsal, lateral and medial views. Brain asymmetries were evaluated by measurements of hemisphere weight, as well as dorsal and lateral areas. From the measurements of the midsagittal callosal areas, performed on the medial views, 2 subgroups could be identified: one with a small callosal remnant (N = 9) and another with a non-measurable callosal area (N = 10). In spite of a pronounced individual asymmetry, the irradiated mice (N = 19) did not show a populational asymmetry toward any side. A slight tendency favoring the left hemisphere was found in the small remnant subgroup. These results are consistent with our previous data for a strain of mice in which some animals present callosal defects. We conclude that the present data support the hypothesis that the corpus callosum may play a role in directing morphological hemispheric asymmetries.

Abnormalities, Radiation-Induced↗
PubMed1989

The effects of total and partial callosal agenesis on the development of morphological brain asymmetries in the BALB/cCF mouse.

The corpus callosum fails to develop in some mice of the BALB/cCF strain. We report here a study on cerebral morphological asymmetry in males of this particular strain in order to test the hypothesis that the normal development of the corpus callosum is responsible for the establishment of brain asymmetries. In 46 animals the dorsal area and the weight of each hemisphere were measured. In order to identify the animals with callosal defects and check for size anomalies of the anterior commissure, the hemispheres were cut into sagittal sections and stained with cresyl violet. Measures of sagittal area of the anterior commissure did not support the hypothesis that this commissure is enlarged when the corpus callosum is reduced or absent. In normal animals, the mean difference between left and right dorsal cortical areas showed a significant directional asymmetry, the left being consistently greater than the right. A similar pattern was found for weight. In mice with callosal defects there were no significant differences, either between the dorsal areas or between the weights of the hemispheres. However, data on the absolute values of the hemispheric differences indicated the presence of a nondirectional asymmetry not only in normal animals, but also in mice with callosal defects. Therefore, our data suggest that the ontogenesis of the corpus callosum plays a role in directing the development of cerebral asymmetries.

Agenesis of Corpus Callosum↗
PubMed1988

Pharmacokinetics of ketamine HCl and metabolite I in the cat: a comparison of i.v., i.m., and rectal administration.

Ketamine HCl [2-(o-chlorophenyl)-2-(methylamino) cyclohexanone HCl] concentrations in whole blood were used to study the pharmacokinetics of i.v., i.m., and rectal administrations, at a dose of 25 mg/kg, in normal domestic cats. Absorption was rapid with both the i.m. and rectal routes. Systemic availability was 51% (SEM 10) for the i.m. dose and 43.5% (SEM 6.1) for the rectal dose. The first-pass effect had a minimal influence on the metabolism of ketamine HCl administered rectally. The elimination rate constant (beta) of the drug was statistically similar in the i.v., i.m., and rectal groups, at a 95% level of significance (P less than 0.05). At the dosage rates studied, ketamine HCl produced an anesthetic effect in the cat following i.v., i.m. and rectal administration.

Administration, Rectal↗
PubMed1988

Effect of diuretics on ketamine and sulfanilate elimination in cats.

Rate constants of elimination were used to evaluate potential effects of diuretic agents on the elimination of ketamine from the blood of cats. Furosemide, mannitol, and aminophylline did not significantly alter the ketamine elimination rate constants, although the diuretics had a tendency to prolong elimination. This tendency of furosemide was further substantiated by observing the effect of furosemide on glomerular filtration. The rate of sulfanilate elimination, used as an indicator of glomerular filtration, was significantly decreased in the cats that were administered furosemide. Possible mechanisms for the influence of furosemide on the renal excretion of ketamine are discussed.

Aminophylline↗
PubMed1987

Effects of prenatal irradiation on the development of cerebral cortex and corpus callosum of the mouse.

Defects of the cerebral cortex and corpus callosum of mice subjected prenatally to gamma irradiation were evaluated as a function of dose and of embryonic age at irradiation. Pregnant mice were exposed to a gamma source at 16, 17, and 19 days of gestation (E16, E17, and E19, respectively), with total doses of 2 Gy and 3 Gy, in order to produce brain defects on their progeny. At 60 postnatal days, the brains of the offspring were analyzed qualitatively and quantitatively and compared with those of nonirradiated animals. Mice irradiated at E16 were all acallosal. Those that were exposed to 2 Gy displayed an aberrant longitudinal bundle typical of other acallosals, but this was not the case in those irradiated with 3 Gy. The corpus callosum of animals irradiated at E17 with 3 Gy was pronouncedly hypotrophic, but milder effects were observed in the other groups. Quantitative analysis confirmed a dependence of callosal midsagittal area upon dose and age at irradiation, and, in addition, indicated an interaction between these variables. The neocortex of irradiated animals was hypotrophic: layers II-III were much more affected than layer V, and this was more affected than layer VI. Quantitative analysis indicated that this effect also depended on dose and age at irradiation and that it was due to a loss of cortical neurons. Furthermore, a positive correlation was found between the number of neurons within layers II-III, and V and the midsagittal area of the corpus callosum. Ectopic neurons were found in the white matter and in layer I of animals irradiated at E16 and E17, indicating that fetal exposure to ionizing radiation interfered with the migration of cortical neuroblasts.

Abnormalities, Radiation-Induced↗
PubMed1986

Dose-dependent occurrence of the aberrant longitudinal bundle in the brains of mice born acallosal after prenatal gamma irradiation.

Two groups of pregnant mice were gamma-irradiated at the 16th gestation day with doses of 2 or 3 Gy. All litters were born acallosal, but while the 3-Gy mice showed a severely hypotrophic neocortex without the aberrant longitudinal bundle typical of early disconnected rodents, in the 2-Gy group the cortex was less deranged and the aberrant bundle appeared consistently underneath the white matter.

Agenesis of Corpus Callosum↗
PubMed1986

Validation of optional elastance-resistance left ventricle pump models.

Left ventricular pressure, P(t), and outflow Q(t), data were collected in anesthetized, open-chest rats and dogs. The data were used in a three-tiered validation procedure to evaluate 14 competing forms of elastance [E(t)]-resistance (R) left ventricle (LV) pump models. Competing models arose from considering two forms of parameterization of E(t), time variation versus no time variation in LV unstretched volume (Vd) and dependence versus no dependence of R on P(t) and isovolumic P(t). A descriptive test based on the normalized root-mean-square errors in the fit to P and, separately, in the fit to Q was used to distinguish between models. The best of the competing models was the one that treated Vd as a function of time and R as a constant. Models of this form fitted the data very well and were said to be descriptively valid. The best of the competing models were then asked to predict the observed responses to changes in afterload, preload, and prior-beat history. The models did not predict these conditions well and failed to pass the test for predictive validity. Additionally, the model parameters were judged not to represent their supposed physical homologs and, thus, failed the test for explanative validity. One cause for E(t)-R model failure was an inadequate representation of events at end systole. This deficiency was apparently due to not accounting for deactivation in the model. Other features may also be needed before a comprehensive LV model can be formulated. Identical conclusions were made from data from the rat and the dog.

Animals↗
PubMed1985

Hiring patterns for non-faculty clinical staff pharmacist positions in institutions greater than 500 beds.

A survey was mailed to 150 randomly-selected hospitals greater than 500 beds to determine: 1) the type of pharmacists currently in non-faculty clinical staff positions; and 2) to assess the hiring philosophy toward such positions. Seventy-two surveys were used to tabulate results. Fifty-eight per cent of the non-faculty clinical positions in the institutions surveyed are held by BS pharmacists. Top preference if rehiring was an advanced degree PharmD or an entry level PharmD with a specialized residency. However, BS pharmacists with clinical experience also ranked high in preference, showing a definite competition with advanced degree pharmacists. Personality and experience seem to become important factors. MS graduates ranked very low, unless their degree was accompanied by a specialized residency. Implications of the survey results are discussed in respect to graduating pharmacy students, academe, and pharmacists currently in the work force.

Education, Pharmacy↗
PubMedDate not supplied

Effects of sex and laterality on the rotatory swimming behavior of normal mice.

Clockwise and counterclockwise full turns are commonly used to assess lateralization in circling behavior. Although previous studies have reported that the rotatory swimming (ROSW) test is simple and reliable, little is known about lateralization of turns lower than 360 degrees and the amount of turning close to the wall, and even less is known about alternation of direction during a session. Here we investigated the effects of consistency of laterality and sex on 30 degree turns in center and in periphery of the swimming apparatus, and on alternation of direction upon three sessions. Approximately 80% of the turns occurred when mice swam along the wall. In side-consistent turners, this suggests the existence of an intrinsic sensorimotor asymmetry that determines the adhesion to the preferred side. Regarding categorization of side preferences, there was a high percentage of agreement between center and periphery, as well as between full turns and extra 30 degree turns (30 degree turns that do not contribute to full turns). Therefore, behavioral asymmetry in the ROSW can be assessed using 30 degree turns. There was no significant directional bias in the population, and side preference was found to be independent of sex. By contrast, after the second minute of each session, males exhibited a significantly higher number of reversal of direction (RD) as well as a higher number of RD per turn than females. The amount of RD presented by each animal is not predicted by the animal's side preference. Thus, RD is independent of preferred side of turning and depends on sex.

Animals↗