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Biomedical subjects

M Wright

Publications and source records attributed to M Wright.

At least 19 recordsLinked to original sources
PubMed1992

Severe botulism after eating home-preserved asparagus.

OBJECTIVE: To present a case of adult botulism acquired in Queensland. CLINICAL FEATURES: After eating home-preserved asparagus, a 33-year-old man presented with internal and external ophthalmoplegia, bilateral facial nerve palsies, and descending muscle weakness culminating in a sudden respiratory arrest. Electrophysiological testing demonstrated normal nerve conduction velocities and an incremental response of evoked motor potentials on repetitive stimulation, confirming the clinical diagnosis of botulism. INTERVENTION AND OUTCOME: Treatment with trivalent antitoxin, oral treatment with vancomycin and supportive mechanical ventilation for four weeks resulted in complete clinical recovery. Plasmapheresis was also used but its contribution to the patient's improvement is dubious. CONCLUSIONS: Although botulism is rare in Australia, clinicians should be aware of the clinical presentation and the rapidity of confirmation of the diagnosis by electrophysiological testing. Patients should be nursed in an intensive care setting. Regular testing of vital capacity should be performed to determine the need for mechanical ventilation.

Adult↗
PubMed1992

Microtubule assembly protects the region 28-38 of the beta-tubulin subunit.

Polyclonal antibodies have been raised against the peptide 28-38 of the beta-subunit of the tubulin heterodimer in order to study the accessibility of this region in the tubulin heterodimer and in various tubulin assemblies. These antibodies were specific for all beta-tubulin subunits, except for beta'-tubulin isotypes, and did not recognize the alpha-tubulin subunit. The 28-38 region does not play a role in the interaction between the alpha- and beta-subunits since it was accessible to the antibodies on the native heterodimer. The accessibility of the antibodies was not modified by several microtubular poisons. In contrast, in all tubulin assemblies obtained in the presence of microtubular associated proteins, the region 28-38 was not available to the antibodies. These antibodies did not react with microtubules or tubulin spirals assembled either from microtubule proteins or from pure tubulin when these tubulin assemblies were probed in the absence of free tubulin after centrifugation on glass coverslips. In addition, antibodies failed to interact with the microtubule cytoskeleton in cultured Ptk2 cells indicating that the 28-38 region of beta-tubulin is also protected in cellular structures. These observations suggest that the 28-38 region of the beta-tubulin subunit is either located in a zone of interaction between two successive tubulin dimers within a protofilament or hidden by an allosteric conformational change which occurs during tubulin assembly.

Amino Acid Sequence↗
PubMed1992

Spontaneous evolution of nuclear size and DNA content of non-small-cell-lung cancers grafted onto nude mice.

We monitored the biological evolution of four human non-small-cell lung cancers labeled KLX6, KLX7, KLX9, and KLX14 that had been grafted onto nude mice. This monitoring was carried out by means of digital cell image analysis which assessed morphometric (nuclear area, NA) and densitometric (nuclear DNA content, DI) features on Feulgen-stained nuclei from imprint smears. In each of the four models, the biological evolution of the NA and DI was characterized through their progression during serial passaging onto nude mice. The results show that of the four lung cancer models analyzed, one (KLX6) remained definitively stable with respect to its DNA content (DI assessments), while the other three, i.e., KLX7, KLX9, and KLX14, varied significantly. As assessed by the morphometric parameter, i.e., the NA, the four xenografted lines also varied significantly over serial passaging. In conclusion, we show that digital cell image analyses of Feulgen-stained cell nuclei including morphometric and densitometric parameters are a powerful tool for monitoring the biological evolution of human lung cancers grafted onto nude mice. We think therefore that the ploidy level of a tumor might be dependent upon its age and/or its related clinical stage.

Animals↗
PubMed1992

Fulminant primary Pseudomonas aeruginosa pneumonia and septicaemia in previously well adults.

We report two cases of primary, community acquired, Pseudomonas aeruginosa pneumonia, occurring in previously well adults without any recognisable environmental risk factors. Both patients died within 36 h of the onset of symptoms, despite broad spectrum antibiotics and aggressive supportive care. In neither case was the diagnosis considered in life and neither patient received adequate anti-pseudomonas therapy. Heightened awareness of this rare, fulminant, variant of primary Pseudomonas pneumonia is required if specific anti-pseudomonas therapy is to have any impact on outcome.

Adult↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1991

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↗
PubMed1979

Computed tomography of infratentorial masses in children.

Seventeen cases of infratentorial mass lesions (excluding abscesses) in children are reviewed. The findings after computed axial tomography (CAT) are described, as well as the changes that were revealed by plain radiographs of the skull. Ancillary investigations were performed in 11 cases, and their usefulness is assessed. The possibility of making a provisional diagnosis of the nature of the lesion based on CAT findings is discussed.

Astrocytoma↗
PubMed1979

Physarum thymidine kinase. A step or a peak enzyme depending upon temperature of growth.

The variations of thymidine kinase or ATP:thymidine 5'-phosphotransferase (EC 2.7.1.21) during the cell cycle of Physarum polycephalum plasmodia have been studied at two extreme physiological temperatures: 22 degrees C and 32 degrees C. At 22 degrees C the enzyme activity increases near mitosis and stays constant during late S and G2 phases, exhibiting the typical pattern of a 'step enzyme'. But at 32 degrees C thymidine kinase activity goes through a maximum 1 h 30 min after mitosis and decreases during the subsequent phases as expected for a 'peak enzyme'. The rate of enzyme degradation and/or inactivation, measured in the presence of metabolic poisons (cycloheximide or dinitrophenol), appears to follow a simple exponential function with a half-life of approximately 3 h and 1 h at 22 degrees C and 32 degrees C respectively. The effect of growth temperature on the decrease of thymidine kinase activity can account entirely for the differences in the pattern of enzyme activity at the two extreme temperatures. Tentative calculations indicate that the rate of enzyme synthesis is nearly constant during the cell cycle except near mitosis, where it is temporarily increased. The results suggest the existence of a regulatory mechanism able to modulate the rate of synthesis of thymidine kinase during the cell cycle.

Cycloheximide↗
PubMed1979

Reversible hypertension due to carcinoma of the ureter.

A patient who presented with hypertension of recent onset was found to have unilateral hydronephrosis. Increased activity of the renin-angiotensin system was documented with renal-vein-renin concentrations. The hydronephrosis was due to a primary transitional cell carcinoma of the ureter. Following nephroureterectomy, blood pressure returned to normal and has remained so for two years.

Blood Urea Nitrogen↗