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Biomedical subjects

R G Wright

Publications and source records attributed to R G Wright.

At least 73 records · Page 4Linked to original sources
PubMed1976

The effect of hyperthermia on the neuroepithelium of the 21-day guinea-pig foetus: histologic and ultrastructural study.

Hyperthermia was induced in guinea-pigs on day 21 of gestation by placing them in an incubator set at 42-5 degrees-43-0 degrees C for 1 hr. At intervals thereafter foetuses were removed from the uterus and sections of the telencephalon were prepared for light and electron microscopy. The histologic and ultrastructural appearance of the telencephalon of the normal 21-day guinea-pig foetus was described for comparative purposes. Damage to cells in mitosis characterised by clumping of chromosomes, and dispersal of polysomes in interphase cells were observed immediately after hyperthermia. Breakdown of the network of junctional complexes was apparent at 4 hr and cellular proliferation was inhibited for 6-8 hr. Degenerative changes and cell deaths were observed deep in the venticular zone after 8 hr; the extent of cell death was related to the post-stressing temperature. Proliferation was resumed at 8 hr and damaged and dead cells moved outward toward the intermediate zone. Phagocytosis of debris by large mononuclear cells was a common finding. Cytoplasmic inclusions, some of which were Feulgen-positive, were present in otherwise normal ventricular cells. Occasional dead cells and empty spaces were present in the ventricular zone at 24 hr and by 48 hr the ventricular zone was normal in appearance. It was concluded that previously observed micrencephaly in the offspring of guine-pig mothers which were heat stressed on day 21 of gestation resulted from a temporary cessation of proliferation and partial depopulation of the proliferating neuroepithelium.

Animals↗
PubMed1976

Gian axonal neuropathy--a generalized disorder of cytoplasmic microfilament formation.

Light and electron microscopy of a sural nerve biopsy obtained from a patient with giant axonal neuropathy revealed the presence of numerous axonal spheroids which were composed chiefly of neurofilaments. Large discrete masses of cytoplasmic microfilaments were also observed in endoneurial fibroblasts, endothelial cells, Schwann cells, perineurial cells and cultured skin fibroblasts. Neuronal degeneration in giant axonal neuropathy appears to be part of a generalized disorder of cytoplasmic microfilament formation.

Axons↗
PubMed1975

Fibroxanthosarcoma of bone.

A tumour arising from the body of the eighth thoracic vertebra is believed to be the first recordedexample of a primary fibroxanthosarcoma of bone. Apart from the absence of a demonstrable storiform pattern, the histology conformed to that of fibroxanthosarcoma of the soft tissues. Ultrastructural studies showed that asteroid-like bodies seen in the cytoplasm of some tumour cells consisted of aggregated centrioles surrounded by cytoplasmic vacuoles. The finding of Langerhans cell granules in some tumour cells supported their identification as histiocytes. These granules have not previously been recorded in the fibrous histiocytoma group of tumours.

Aged↗
PubMedDate not supplied

Cost-effectiveness studies on cervical cancer.

Cost-effectiveness analyses are an important source of information for the design and evaluation of policies to reduce cervical cancer. This paper describes the recommendations of a panel on cost-effectiveness studies convened as part of the International Consensus Conference on the Fight Against Cervical Cancer. Recommendations for cost-effectiveness studies include: (1) the use of reference case methods to support comparisons across studies, (2) the use of a consistent standard of evidence on the clinical effectiveness of different screening strategies, (3)further research into the costs and effectiveness of different screening and treatment strategies for cervical cancer, (4) further research into screening and treatment strategies in a wide range of countries, (5) easily accessible and detailed descriptions of the methods and supplementary analyses underlying published studies, (6) greater use of newly developed models of cervical cancer, and (7) greater revelation of potential conflict of interest by researchers.

Conflict of Interest↗
PubMedDate not supplied

Quality assurance and risk reduction guidelines.

Cervical cancer continues to be a major cause of death in women worldwide. The major problem facing most women is the unavailability of screening Pap tests in poor and underdeveloped countries. While rates of cancer deaths have decreased 60-80% in developed countries since the Pap test became available, the accuracy of Paps was challenged recently. In order to instill public confidence and promote optimal patient care, measures to improve the quality of the entire screening process should be undertaken. Continuous quality improvement processes are more appropriate than traditional quality assurance monitors. Although no standards can be defined that are applicable to all laboratory settings and nations, this document provides current views on universal quality procedures and risk reduction. Procedure/policy manuals, workload assessment, hierarchic/peer review, discrepancy analysis, rescreening studies and cytohistologic correlation are examples of universally applicable quality tools. The variability in practices in different parts of the world is also discussed.

Female↗
PubMedDate not supplied

Quality assurance in cervical cytology screening. Comparison of rapid rescreening and the PAPNET Testing System.

OBJECTIVE: To assess the performance of the PAPNET Testing System and compare the sensitivity of this automated device with that of rapid rescreening. STUDY DESIGN: In this study, 1,000 cervical smears previously diagnosed by our laboratory as negative were seeded with 20 particularly "difficult" cases. We submitted this seeded set of smears for rapid rescreening and to PAPNET to determine cases that could be detected by rapid rescreening, PAPNET or both. RESULTS: Rapid rescreening detected 9 of the 20 cases (45%). The PAPNET system identified 19/20 (95%). This investigation found PAPNET rescreening to be more effective than rapid rescreening in detecting the seeded difficult cases. CONCLUSION: Use of the PAPNET Testing System in tandem with rapid rescreening can reduce the rate of false negatives in diagnostically difficult cervical cytologic smears.

Automation↗
PubMedDate not supplied

Anesthetic considerations for myasthenia gravis and pregnancy.

Three pregnant patients with myasthenia gravis are presented and anesthetic considerations discussed. The course of myasthenia gravis is highly variable and unpredictable during pregnancy. Anticholinesterase therapy should be maintained during labor, and the IM route of administration is preferred. Exacerbations very often occur in the immediate postpartum period. Regional anesthesia is preferred for vaginal delivery. In the case of cesarean section, general anesthesia may be preferable. Neonatal myasthenia gravis is a transient syndrome that appears in 20 to 30% of the newborns of myasthenic mothers.

Adult↗