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Biomedical subjects

J Thorpe

Publications and source records attributed to J Thorpe.

At least 19 recordsLinked to original sources
PubMed1996

Encore, a gene required for the regulation of germ line mitosis and oocyte differentiation during Drosophila oogenesis.

During Drosophila oogenesis, a stem cell daughter undergoes precisely four rounds of mitosis to generate a cyst of 16 cells interconnected by cytoplasmic bridges. One of the cells becomes the oocyte while the remaining 15 cells differentiate as nurse cells. We hve identified a gene, encore, that is involved both in regulating the number of germline mitoses and in the process of oocyte differentation. Mutations in encore result in exactly one extra round of mitosis in the germline. Genetic and molecular studies indicate that this mitotic defect may be mediated through the gene bag-of-marbles. The isolation and characterization of multiple alleles of encore revealed that they were all temperature sensitive for this phenotype. Mutations in encore also affect the process of oocyte differentiation. Egg chambers are produced in which the oocyte nucleus has undergone endoreplication often resulting in the formation of 16 nurse cells. We argue that these two phenotypes produced by mutations in encore represent two independent requirements for encore during oogenesis.

Alleles↗
PubMed1995

High resolution magnetic resonance imaging of the anterior visual pathway in patients with optic neuropathies using fast spin echo and phased array local coils.

High resolution MRI of the anterior visual pathways was evaluated using frequency selective fat suppressed fast spin echo (FSE) sequences in conjunction with phased array local coils in patients with optic neuropathies. Fifteen normal controls and 57 patients were examined. Coronal T2 weighted fat suppressed FSE images were obtained in 11 minutes with an in plane resolution of 0.39 x 0.39 mm. The optic nerve and its sheath containing CSF were clearly differentiated. Central retinal vessels were often visible. In demyelinating optic neuritis and in anterior ischaemic optic neuropathy high signal within the nerve was readily delineated. Meningiomas and gliomas involving the optic nerve were precisely visualised both in the orbit and intracranially. Extrinsic compression of the optic nerves was readily visualised in carotid artery ectasia and dysthyroid eye disease. Enlarged subarachnoid spaces around the optic nerves were demonstrated in benign intracranial hypertension. High resolution MRI of the anterior visual pathway represents an advance in the diagnosis and management of patients presenting with optic neuropathy.

Adult↗
PubMed1994

Preliminary evidence from magnetic resonance imaging for reduction in disease activity after lymphocyte depletion in multiple sclerosis.

The central nervous system lesions of multiple sclerosis (MS) can be detected by magnetic resonance imaging (MRI) and the initial perivascular inflammatory component is distinguished by the presence of gadolinium enhancement. To assess the effect of systemic lymphocyte depletion on disease activity, seven patients with MS received a 10-day intravenous course of the humanised monoclonal antibody CAMPATH-1H (anti-CDw52). With some variations in the protocol, enhanced cerebral MR images were obtained monthly for 3-4 months before and at least 6 months after treatment. 28 enhancing areas were detected on the first series of 7 scans; 51 additional active lesions were identified on 18 scans before treatment; 15 were detected on 20 scans done over the next 3 months, but only 2 active lesions were seen on 23 scans during follow-up beyond 3 months. The difference in lesion incidence rate before and after treatment varied and the rate ratio was significantly reduced in only three patients. Collectively, in a "meta-analysis", the rate ratios were 0.15 [corrected] (95% CI 0.09-0.24) for all seven patients and 0.24 (0.14-0.42; p < 0.001) with exclusion of the patient whose scanning schedule differed. The effect of CAMPATH-1H on disease activity provides direct, but preliminary, evidence that disease activity in MS depends on the availability of circulating lymphocytes and can be prevented by lymphocyte depletion. It is too early to say anything about the clinical results of treatment with this agent.

Antigens, CD↗
PubMed1994

Comorbidity of other chronic age-dependent diseases in dementia.

This study compares the prevalence rates of 5 common age-dependent diseases in non-demented and demented subjects. Control and dementia populations were approximately age-matched and their numbers also approximated. Prevalence rates for hypertension, myocardial infarction (MI), stroke, cancer and diabetes were determined. The rates of two or more coexisting diseases in the same patient were also compared. Two populations were studied: one was designated the autopsy series, and the other the hospital series. In the autopsy series, the rate of cardiomegaly/hypertension was 1.3 times higher in the control than in the dementia population, and for MI it was 1.7 times higher in the former than in the latter. The rate for stroke was higher in the control group by only a factor of 1.1, for cancer by only a factor of 1.2, and for diabetes the rates were almost identical in the two populations. The rate differences were statistically significant only with respect to cardiomegaly and MI. When the non-vascular and vascular dementias were compared, the rates in the latter were higher by only a factor of 1.3 for cardiomegaly, stroke, cancer and diabetes; for MIs, the rates were about the same in the two dementia categories. The data for two or more coexisting diseases were almost identical in control and dementia autopsy populations. In the hospital series, the hypertension rate was 1.6 times higher in the control than in the Alzheimer's disease (AD) group; for MI, the control group was higher by a factor of 1.5.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Schizosaccharomyces pombe mitochondria: morphological, respiratory and protein import characteristics.

A technique is described for the isolation and purification of intact, respiratory-competent mitochondria from Schizosaccharomyces pombe. The purified mitochondria are capable of oxidizing NADH and succinate as respiratory substrates, indicating the presence of succinate dehydrogenase and an NADH dehydrogenase located on the outer surface of the inner membrane. Mitochondria display good respiratory control with an ADP/O ratio of < 2. Respiratory activity is linearly dependent upon the redox poise of the quinone pool, suggesting the presence of an unbranched respiratory pathway to molecular oxygen. Immunogold labelling using antisera raised against mitochondrial HSP70 proteins (SSP1, SSC1 and PHSP1) from three different species, namely S. pombe, Saccharomyces cerevisiae and the plant Pisum sativum respectively, has been used to investigate the presence and ultrastructure of the mitochondria isolated by this procedure. The immunocytochemistry was carried out using cells containing wild-type levels of SSP1 protein and cells over-expressing the protein. These results also demonstrate the capacity of mitochondria to import increased levels of protein in vivo. In vitro import experiments using COXIV-DHFR indicate that purified S. pombe mitochondria can efficiently import this precursor, and that protein translocation is dependent upon an oxidizable substrate and a membrane potential.

Amino Acid Sequence↗
PubMed1992

Teaching children with autism through task variation in physical education.

The purpose of the study was to determine whether the technique of task variation (with maintenance tasks interspersed) (TV) is more effective in the acquisition of gross motor skills for students with autism than a constant task (CT) condition in a physical education setting. Subjects were 12 male students with autism, ages 11 to 15 years. The study included pretest-posttest administration of the I CAN assessment of Gross Motor Skills to assess skills such as overhand throw, kick, and vertical jump. After a 6-week treatment period, the TV condition was significantly more effective than the CT condition, at the .05 level.

Adolescent↗
PubMed1979

Hepatic enzymes of tyrosine metabolism in tyrosinemia II.

A middle-aged adult male with a mild form of tyrosinemia II (Richner-Hanhart syndrome) is described. Treatment with a low-tyrosine diet caused a fall in plasma tyrosine and clearing of the hyperkeratosis of the soles. Liver biopsy of this patient revealed low but measurable levels of cytoplasmic tyrosine aminotransferase and elevated levels of the mitochondrial tyrosine-metabolizing enzyme aspartate aminotransferase. It is hypothesized that these enzymes have been induced in sufficient amounts to account for the mild clinical course.

Amino Acid Metabolism, Inborn Errors↗
PubMed1977

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California↗