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Biomedical subjects

J M Talbot

Publications and source records attributed to J M Talbot.

At least 37 records · Page 2Linked to original sources

Otic capsule dysplasia: clinical and CT findings.

Many congenital dysplasias of the osseous labyrinth have been identified. Differentiation of these dysplasias is essential for patient management. High-resolution computed tomography (CT) was used to identify individual malformations in 32 patients. Thirty patients had six previously described forms, while two patients had a form that has not previously been reported to our knowledge. Review of patient histories revealed clinical characteristics that were specific for certain forms of otic capsule dysplasia. CT enabled detailed analysis of each lesion and helped direct proper treatment of each patient. The characteristic CT appearance and clinical presentation of each form of dysplasia are presented.

Congenital Abnormalities↗

Potential hearing loss resulting from MR imaging.

To determine if the loud noise generated by magnetic resonance (MR) imaging equipment is capable of inducing hearing loss, the hearing of 24 patients was tested before and after MR imaging. Fourteen patients were imaged without ear protection, and six (43%) suffered a temporary, mild loss of hearing (less than or equal to 15 dB at at least one frequency). Ten patients were imaged with ear protection, and only one experienced any hearing loss. Therefore, the noise generated by MR imagers may cause temporary hearing loss, and earplugs can prevent this loss. All threshold changes had returned to within 10 dB of baseline by 15 minutes after completion of the second audiometric test.

Adult↗

Nutrition and metabolism in spaceflight.

The United States Space Station being planned for the 1990s will accommodate six or more crew members on 90-d flights in low earth orbit. Adequate nutrition will be essential for maintaining crew health, effectiveness and morale. Although much is known from prior space experience about in-flight metabolism, nutrition and associated food technology, important gaps in knowledge exist that need additional research, development and analysis to meet Space Station requirements. This paper is a synopsis of a report prepared by the Life Sciences Research Office (LSRO), FASEB, from a study of the nutritional and metabolic aspects of spaceflight. It reviews available data on the metabolic responses to spaceflight including extravehicular activity, physiological responses to microgravity that influence metabolism and energy needs, in-flight nutritional experience, space menus, food packaging, in-flight food service methodology, water supply and disposal of food wastes. The LSRO ad hoc Working Group identified critical gaps in knowledge and suggested corresponding research approaches for acquiring essential new data. The 38 research suggestions detailed in the report address in-flight metabolic needs, nutrient requirements, food systems and nutritional countermeasures.

Diet↗

A review of the psychological aspects of space flight.

Instances of overt, serious functional impairment of space crews caused by adverse psychologic responses have not been scientifically documented. However, transient disorientation, spatial illusions, and visual disturbances as well as anomalous myopias, sleep disturbances, and instances of substandard performance have been described. Moreover, anecdotal information describes significant psychologic aberrations in space flight. Adequate scientific data are lacking for optimal psychological and psychophysiological methods for crew selection, training, and performance evaluation, for identifying key psychosocial factors for crew compatibility, cohesiveness, and productivity, and for determining the effects of space flight on perceptual, intellectual, and motor skills. The ad hoc Working Group, convened to review psychological aspects of space flight, favored establishment of a comprehensive research and development program to address the deficiencies identified in the study.

Behavior↗

Influence of space flight on red blood cells.

Losses of red blood cell mass (RCM) averaging 10-15% have been observed consistently in astronauts after space flight; postflight recovery of RCM requires 4-6 wk. Although apparently not harmful to the health and effectiveness of crews during uncomplicated flights, decreased RCM could compromise health and performance in the event of illness, injury, or partial malfunction of the life support system. Whether the loss of RCM would worsen or stabilize in missions longer than 7 months is unknown. As a biological response, it is a significant, predictable reaction whose etiology, biological mechanisms, and potential operational significance are inadequately defined. Weightlessness is probably the primary cause; however, contributory factors may include hypokinesia/hypodynamia, bone loss, muscle atrophy, altered hemodynamics, stress, and metabolic disturbances. Space medical specialists consider other possible influences such as hypoxia, hypobaria, radiation, toxic contaminants, and launch and reentry accelerations as less likely factors. Because the data base on loss of RCM is insufficient for the National Aeronautics and Space Administration's space medical responsibilities, the Life Sciences Research Office ad hoc Working Group on Space Anemia suggested research approaches ranging form fundamental topics such as utilization of erythropoietin and oxygen in target organs and cell-cell interactions, through possible splenic and vascular dysfunctions, metabolic disturbances, and inhibitors of erythropoiesis, to methodology and models.

Body Weight↗

Space sickness.

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Aerospace Medicine↗

Investigation and control of an outbreaks of legionnaires' disease in a district general hospital.

Between December, 1979, and July, 1980, 12 cases of legionnaires' disease were recognised in a district general hospital. 11 of the patients probably acquired their infection within the hospital. Epidemiological and environmental studies indicated that the plumbing system and possibly also the air-conditioning cooling-tower exhaust in the new building of the hospital were the sources of infection. Chlorination of the cold-water supply and raising the hot-water temperature appeared to terminate the outbreak.

Adult↗

A clinical assessment of nine pregnancies obtained by in vitro fertilization and embryo transfer.

An analysis of nine pregnancies resulting from in vitro fertilization and embryo transfer was made in order to identify factors common to all of the pregnancies. These factors included clomiphene stimulation; general anesthesia for laparoscopy; identification of large follicles (greater than 8 ml) and a mature oocyte; preincubation of the oocyte for 4.7 to 6.5 hours in vitro before insemination; insemination with 0.8 to 1.3 x 10(6) fresh spermatozoa from fertile samples; transfer to the uterus of two-, four-, and eight-cell embryos, 38 to 50 hours after insemination; and uncomplicated uterine transfers of embryos. It was difficult to determine whether these factors are causal or coincidental in the attainment of successful pregnancies. The detailed analysis was useful in demonstrating factors which did not prevent the establishment of pregnancy by in vitro fertilization and embryo transfer. These factors included a variety of causes of infertility, including idiopathic and male infertility; age of the infertile woman over 35 years; the presence of T-mycoplasma in the genital tract; the use of human chorionic gonadotropin; a variety of agents used for general anesthesia; the use of carbon dioxide to induce pneumoperitoneum; a delay of up to 50 minutes in the interval between the induction of general anesthesia and oocyte recovery; the use of antiprostaglandins at the time of embryo transfer; and a brown discharge from the vagina following embryo transfer.

Embryo Transfer↗

Role of dietary fiber in diverticular disease and colon cancer.

This paper reviews recent research on the characterization, properties, and definition of dietary fiber as well as its possible role in colonic carcinogenesis and diverticulosis. Despite progress in analytic methods and characterization, an accepted definition and terminology for fiber are lacking as is an accurate, rapid method for measurement of total dietary fiber or fiber in foods. Mechanisms of effects of fiber in the gut and the significant of interactions between fiber, nutrients gut flora and associated metabolites, and enteric secretions are unclear. Epidemiologic and experimental data indicate an increased risk of diverticular disease and colonic cancer with low-fiber intakes; however, genetic, environmental, cultural, dietary, and other variables were often uncontrolled in the epidemiologic studies. Thus, conclusive evidence for a causal relationship between low intake of fiber and diverticulosis or colonic cancer is not available, and the question whether first protects against human colonic cancer and/or diverticulosis is not completely resolved. Clinical trials in which symptomatic diverticular disease was treated with supplementary dietary fiber have generally had favorable results. Numerous specific questions require additional study before a role for dietary fiber in the prevention of human colonic diverticulosis and cancer of the colon can be established. Suggestions for possible future investigation are provided.

Cellulose↗

Attitudinal and nonattitudinal determinants of contraception: a cross-cultural study.

Survey data from women in pregnancy risk in Venezuela and Kenya are used to examine the determinants of contraceptive intention, use, and the intention/use consistency. The five ranking determinants of contraceptive use are: intention to contracept, social support, accessibility, conjugal communication, and desire for additional children. All five determinants have direct and additive effects on contraception, but their relative impacts vary significantly between the two cultures. Contraceptive intention and use are highly consistent, while level of consistency varies significantly between the two samples and within each by various combinations of ranking variables and by parity. Major research and policy implications of the results are reviewed.

Adolescent↗