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Biomedical subjects

M Wright

Publications and source records attributed to M Wright.

At least 199 records · Page 11Linked to original sources

Leadership orientations of hospital pharmacy directors.

This research is intended to improve understanding of the leadership orientations of hospital pharmacy directors. The results of the study suggest that these pharmacy directors have not assumed leadership roles within the network of social relationships in the organization. One explanation is that descriptive theories are of little relevance to current practice. Another explanation is that these pharmacy directors are not prepared to value and to be competent at leadership roles. In the absence of measures of effectiveness, these results are difficult to evaluate in terms of the need to cultivate leadership skills in pharmacy directors. Nevertheless, cultivating such skills may be desirable because the pharmacy directors participating in this study perceive that they are less prepared to engage in relationships with people external to the pharmacy department than with members of the department. Enhanced competence would create the potential for higher perceived value and may yield shifts in actual behavior.

Chicago↗

A comparison of the effectiveness of sensory integrative therapy and perceptual-motor training in treating children with learning disabilities.

This study compared the effect of sensory integration therapy (SI), perceptual-motor training (PM) and no treatment (NT) on the performance of 103 children with learning disabilities and sensory integrative dysfunction, aged 58 to 107 months, who were randomly assigned to one of the two treatment groups or to no treatment. After receiving a total of 72 1-hour sessions of therapy for 3 hours per week, PM-treated subjects showed significant gains over the other two groups, primarily in gross motor performance. SI-treated subjects showed an advantage in motor planning. There were no accompanying group differences in visual perception, handwriting readiness, copying ability, cognitive, academic, language and attentional skills or in self-concept. These findings demonstrate motor gains resulting from motor treatments without carry-over to functional skills and abilities more directly associated with school performance.

Attention↗

Cell cycle-dependent assembly and disassembly of cytoplasmic microtubules in the plasmodium of the myxomycete Physarum polycephalum.

The giant syncytium of Physarum plasmodia possesses a complex cytoplasmic microtubule network except during the occurrence of the intranuclear mitosis. In early prophase stages, intranuclear spindles assemble concomitantly as the cytoplasmic microtubule network disassembles. No cytoplasmic microtubules are present in metaphase. They begin to reassemble in telophase. The complex cytoplasmic microtubule network reappears in early reconstruction stages. The assembly of cytoplasmic microtubules occurs on cytoplasmic foci, both in telophase stage and during rewarming after cold microtubule disassembly. These foci, independent of the nuclei, correspond to the foci observed in the cytoplasm during interphase, both by immunofluorescence and electron microscopy. As cytoplasmic and intranuclear microtubule-organizing centers are spatially distinct, plasmodial syncytia offer the possibility to study the effects of cell regulatory pathways on two types of microtubule-organizing centers that differ in their nucleating activity during the cell cycle.

Animals↗

Immersion events in residential swimming pools. Evidence for an experience effect.

BACKGROUND: --Drowning and near-drowning in residential swimming pools are leading causes of morbidity and mortality for young children. We tested the hypothesis that the period immediately after a pool is acquired is a time of high risk for these events. This study was also designed to provide population-based data on swimming pool immersion events, regardless of severity. METHODS: --We conducted a mail survey of a probability sample of Sacramento County, California, households with in-ground swimming pools in January 1988; 80% of eligible subjects responded. Onset of exposure to a pool was defined as the month in which (1) the responding household had a pool installed, or (2) the responding household first occupied a residence with a pool. Exposures began in 1959 through 1987. RESULTS: --The home swimming pool immersion event rate was 11 per 1000 pool-years. The rate per 1000 pool-years was higher for the first 6 months of exposure than thereafter (0 to 6 months, 44; 7 to 24 months, 14; greater than 24 months, seven), but 77% of events occurred outside the high-risk period. For households whose exposures began in 1984 through 1987, the immersion event rate was 51 per 1000 pool-years overall and 123 per 1000 pool-years for the first 6 months of pool exposure; these increases probably represent underreporting of earlier events. In this group, 48% of events occurred outside the high-risk period. The family swimming pool accounted for 91% of immersion events at the respondents' homes. CONCLUSIONS: --The residential swimming pool is an important hazard for pool-owning households. The first 6 months of exposure constitute a high-risk period, but many immersion events occur later. Pool drowning prevention programs may focus on newly acquired swimming pools and their owners but should be as broad as possible to maximize their effectiveness.

California↗

Differential in vitro action of S-12363, a new vinblastine derivative, and of its epimer on microtubule proteins.

The action of two epimers of a new vinblastine derivative that differ in their in vivo antitumor activity and their cytotoxicity was studied in vitro in brain microtubule proteins. These two compounds, called S-12363 and S-12362, could not be distinguished from one another or from other active vinca alkaloids by their ability to prevent microtubule assembly. However, they differed strongly both from one another and from vincristine and vinblastine in their ability to induce the formation of tubulin paracrystals and in the stability of the paracrystals following temperature shifts from 0 degree to 37 degrees C and vice versa. The most potent drug, S-12363, induced considerable tubulin aggregation, which was even more pronounced than that observed in the presence of vincristine. Previous results have shown that S-12363, in contrast to vincristine, induces no neurotoxic effects. This observation is in disagreement with a direct relationship between tubulin aggregation and neurotoxicity.

Animals↗

Computer image processing and automatic counting and measuring of fouling organisms.

The purpose of this study was to optimize the counting and measuring of marine fouling organisms on experimental panels using automated computer techniques. A script was developed that reduced the time required for the counting and measuring of marine fouling tubeworms by at least one order of magnitude over manual counts, with an error of five percent or less. Small, distinct tubeworms can be successfully counted by computer using a correction factor. Measurements of percentage cover or area should be made with larger tubeworms that have overlapping tubes.

Animals↗

Effect of abnormal levels of serum components on antibiotic activity.

Antibiotic activity in serum from a model for type II diabetes was similar to that in normal sera or media containing cholesterol but lacking glucose, insulin, or both. The ratio of effects of broth plus obese-rat serum to effects of broth plus lean-rat serum supplemented with cholesterol approached or equaled 1.

Animals↗

Physarum plasmodia do contain cytoplasmic microtubules!

It has been claimed that the plasmodium of the myxomycete Physarum polycephalum constitutes a very unusual syncytium, devoid of cytoplasmic microtubules. In contrast, we have observed a cytoplasmic microtubule network, by both electron microscopy and immunofluorescence in standard synchronous plasmodia, either in semi-thin sections or in smears, and in thin plasmodia, used as a convenient model. Cytoplasmic microtubules could be seen after immunofluorescent staining with three different monospecific monoclonal anti-tubulin antibodies. The immunolabelling was strictly restricted to typical microtubules as shown by electron microscopy. These cytoplasmic microtubules were entirely and reversibly disassembled by cold treatment and by either of two microtubule poisons: methyl benzimidazole carbamate and griseofulvin. The microtubule network, present in all strains that have been studied, contains single microtubules and microtubule bundles composed of two to eight microtubules. Cytoplasmic microtubules form a dense and complex three-dimensional network, distinct from the microfilamentous domains and from the nuclei. The orientation of the microtubule network varies according to the plasmodial domain examined. Generally microtubules show no special orientation except in plasmodial veins where they are oriented parallel to the long axis of the veins. Differences between our observations and those of previous workers who failed to find cytoplasmic microtubules in plasmodia are discussed. We propose that they reflect difficulties of observation mainly due to the fluorescent background. In contrast with the previous view, the discovery of a microtubule cytoplasmic cytoskeleton in Physarum plasmodia raises several questions concerning its relationships with other cellular organelles and its dynamics during different cell cycle events.

Animals↗

Genetic analysis of the relationships between the amoebal extranuclear spindle-organizing centre and the plasmodial intranuclear spindle-organizing centre of Physarum during conjugation.

Physarum amoebae possess an extranuclear spindle-organizing centre (abbreviated SPOC), located in a typical centrosome with a pair of associated centrioles while plasmodia possess an intranuclear SPOC without centrioles. In order to ascertain whether, during conjugation, the plasmodial SPOC is derived from the amoebal one or is not related to it, we have constructed amoebal strains possessing two and three SPOCs and we have used as a genetic marker the frequency of polycentric metaphases in order to evaluate the number of SPOCs in the plasmodia. The results of both symmetrical crosses, i.e. between amoebae possessing the same number of SPOCs, and asymmetrical crosses, i.e. between amoebae possessing a different number of SPOCs, show that: (1) the number of SPOCs in plasmodia is dependent upon the number of SPOCs in either one of the two parental amoeba; (2) in no cross does the number of plasmodial SPOCs equal the sum of the parental amoebal SPOCs, but it corresponds to that of only one parent without any polarity of transmission in asymmetrical crosses. These results are consistent with the following model: (1) plasmodial SPOCs are derived from the amoebal ones; and (2) one set of parental SPOCs is lost, destroyed or inactivated in the zygote.

Animals↗

Quantitative autoradiographic changes in 5-[3H]HT-labeled 5-HT1 serotonin receptors in discrete regions of brain in the rat model of persistent dyskinesias induced by iminodipropionitrile (IDPN).

Chronic injections of iminodipropionitrile (IDPN) to rat cause a persistent motor hyperactivity, lateral and vertical sustained twisting movement of the neck, random circling and increased startle response. These abnormalities are similar to those observed after the acute administration of serotonin (5-HT) agonists in rodents. Significant changes in 5-HT concentration and in 5-HT2 receptor density in several motor-related brain regions have been observed in IDPN-treated rats. The present quantitative autoradiographic study was undertaken to assess the possibility that IDPN may also affect 5-HT1 receptors in rat brain. IDPN caused significant increases of 5-[3H]HT binding in the oriens and pyramidal layers of the CA3 field of hippocampus. In contrast, there were significant decreases of 5-[3H]HT binding in the frontal and cingulate cortices, the olfactory tubercle, the ventromedial aspect of the caudate-putamen, the nucleus accumbens, the superior colliculus, and the lateral septal nuclei. These results provide further evidence for the involvement of the 5-HT system in the development of the IDPN-induced dyskinetic syndrome.

Animals↗

Polypeptides from the myxomycete Physarum polycephalum interacting in vitro with microtubules.

Microtubule-interacting proteins have been studied in the lower eukaryote Physarum polycephalum. We show for the first time 1) the presence in Physarum amoebal crude extracts of at least six polypeptides that bind specifically to amoebal microtubules, 2) the binding between these proteins and mammalian microtubules, 3) the heat stability of two of these polypeptides (125 and 235 kDa), 4) the functional properties of a fraction containing a heat-soluble 125 kDa polypeptide, and 5) the phosphorylation of the 125 kDa polypeptide during two distinct periods of the cell cycle in Physarum synchronous plasmodia, first at late S/early G2 phase and second at late G2/prophase.

Animals↗

Regulation of tubulin synthesis during the cell cycle in the synchronous plasmodia of Physarum polycephalum.

Regulation of alpha- and beta-tubulin isotype synthesis during the cell cycle has been studied in the myxomycete Physarum polycephalum, by subjecting synchronous plasmodia to temperature shifts and pharmacological perturbations. Temperature shifts interfered with the regulation of tubulin synthesis. Inhibition of DNA synthesis prevents tubulin degradation after completion of the cell cycle (Ducommun and Wright, Eur. J. Cell Biol., 50:48-55, 1989) but did not perturb the initiation of tubulin synthesis. The constant increase of tubulin synthesis in the presence of tubulin-sequestering drugs and the decrease of tubulin synthesis during a treatment with aphidicolin in late G2 phase suggest the existence of an autoregulatory mechanism of tubulin synthesis. Moreover, the microtubule poison methyl benzimidazole carbamate dissociated synthesis of the alpha 1-tubulin isotype from the generally strictly coordinated synthesis of all tubulin isotypes during the transient interruption of mitosis. These observations show that a microtubular poison can perturb regulation of the synthesis of specific isotubulins.

Aphidicolin↗

Alcohol and drowning: an analysis of contributing factors and a discussion of criteria for case selection.

We test the hypothesis that there are host or environmental factors that significantly affect the likelihood of alcohol involvement in drownings. Our results are based on records of 234 drownings that meet predetermined eligibility criteria designed to exclude cases with postmortem blood alcohol concentrations (BACs) that do not reflect the BAC at the time of immersion. Cases are drawn from a total of 442 drownings occurring in Sacramento County, California, from 1974 to 1985. Overall, 41% of deaths were alcohol-associated; among these only one victim was under 15 years old. Among older persons, increasing age generally suggested a higher likelihood of alcohol involvement, and particularly of a BAC greater than 200 mg/dl. Other associated factors were male gender (OR = 2.5; 95% CI = 1.6, 3.8), activity (for land motor-vehicle occupants vs. all others, OR = 3.3; 95% CI = 2.6, 4.3), and time of year (January-June vs. July-December, OR = 2.1; 95% CI = 1.6, 2.8). A lower likelihood of alcohol involvement was seen for drownings in bathtubs (OR = .16; 95% CI = .04, .57) and swimming pools (OR = .47; 95% CI = .27, .82). Race was not a factor. Differing eligibility criteria have been used in studies of alcohol and drowning. After a critical review of the experimental literature, we propose that the following be adopted in future such studies: (i) death must occur within six hours of the onset of immersion, unless an antemortem sample is available and, unless evidence to the contrary exists, death can be assumed to have occurred within a few minutes of immersion; (ii) blood must be drawn for BAC determination within 24 hours of death.

Adolescent↗

Development of a somatic cell hybrid mapping panel and molecular probes for human chromosome 3.

A somatic cell hybrid mapping panel and molecular probes have been developed for human chromosome 3. This panel defines 11 regions for the short and long arms of the chromosome. Four hundred thirty-two probes have been mapped using these hybrids. One hundred thirty-one of these probes were derived from EcoRI and HindIII flow-sorted libraries. The remaining 301 probes were isolated from NotI boundary and random (partial MboI) libraries constructed from a hybrid that provided a relative enrichment in 3p DNA sequences. For some regions of the chromosome, significant differences in the distribution of probes were noted. This was observed for both the unique sequence flow-sorted and NotI probes. These differences are in agreement with previous suggestions that Giemsa light bands are GC-rich, and therefore gene-rich (especially housekeeping genes), and that the Giemsa dark bands may contain DNA that is more highly condensed. The isolation of probes from different types of libraries, or by different screening strategies, appears to reduce deficiencies that might arise from the use of probes derived with a more limited approach. These hybrids and probes should facilitate the construction of physical and genetic linkage maps to identify various disease loci involving chromosome 3.

Animals↗