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Biomedical subjects

C Ryan

Publications and source records attributed to C Ryan.

At least 127 records · Page 7Linked to original sources
PubMed1986

Experiments with continuous hemofiltration and hemofiltrate regeneration in the rat.

Experimental studies were made with continuous hemofiltration treatment for bilaterally nephrectomized rats and initial observations regarding the effects of such treatment on leukocyte and thrombocyte counts are reported. Hemofiltration of unanesthetized rats able to move freely within their cage could be continued for up to 30 h using a pump-driven ECC system. Blood parameters recorded during this treatment indicate that the detoxification was effective. In another series of experiments the water and electrolyte reabsorption capacity of the colon ascendens of healthy rats was tested by continuously supplying NaCl solution into the colon via a fistula. A large proportion, if not all, of the hemofiltrate can be discharged into the colon without diarrhoea. A final series of experiments showed that the three-stage operation (implantation of permanent catheters, connection of a permanent intestinal fistula and bilateral nephrectomy) is possible with the rat.

Animals↗
PubMed1985

Neonatal 6-hydroxydopamine lesion of spinal norepinephrine terminals fails to affect the ontogeny of swimming behavior.

Newborn rats were injected either systemically or intraspinally with 6-hydroxydopamine. Both treatments drastically reduced spinal norepinephrine (NE), while the former also reduced forebrain NE. Spinal NE loss did not affect the ontogeny or the adult expression of swimming, a sensitive test of complex patterned locomotion. Spinal NE is not essential to either the ontogeny of complex motor behavior or to the generation of such behavior in adult rats.

Animals↗
PubMed1985

Learning deficits in adolescents with anorexia nervosa.

Learning ability was examined in a group of female adolescents hospitalized with anorexia nervosa, and in groups of demographically similar depressed inpatients, diabetic outpatients, and healthy normal subjects. Results showed that the group of anorectic females was significantly impaired on a difficult symbol-digit paired-associate learning test, but did not differ from control subjects on measures of attention, immediate or delayed visual memory, and psychomotor ability. Whereas performance on the Symbol-Digit Learning Test was found to be independent of acute weight loss at the time of testing, a significant relationship was obtained between learning ability and duration of illness.

Adolescent↗
PubMed1985

Tricyclics: possible treatment for posttraumatic stress disorder.

The response to tricyclic antidepressants (TCAs) was examined in 17 combat veterans with DSM-III defined posttraumatic stress disorder (PTSD) by means of concurrent and retrospective chart review. Severity and improvement were determined by means of Clinical Global Impressions (CGI) ratings by two independent but nonblind raters who demonstrated satisfactory reliability. Prior to treatment, 82% were rated as markedly or severely ill and 18% as moderately ill. Following treatment, 82% were rated as much improved and 18% as minimally improved. The results support further investigation of TCAs for the treatment of PTSD.

Adult↗
PubMed1985

Cognitive deficits in adolescents who developed diabetes early in life.

A comprehensive battery of neuropsychological tests was administered to 125 adolescents with a history of insulin-dependent diabetes, and to 83 demographically similar nondiabetic control subjects. To test the hypothesis that developing this disease early in life greatly increases the risk of manifesting significant cognitive impairments, diabetic subjects were assigned to an "early-onset" (diagnosis before age 5 years) or a "later-onset" subgroup. Results showed that subjects with early onset of diabetes performed more poorly than either subjects with later onset of diabetes or nondiabetic control subjects on virtually all tests, including measures of intelligence, school achievement, visuospatial ability, memory, motor speed, and eye-hand coordination. Moreover, multiple regression analyses demonstrated that the age at onset and the duration of diabetes seem to affect neuropsychological functioning in very different ways. The duration of the disease best predicted performance on those tests requiring highly overlearned, primarily verbal, skills whereas the age at onset best predicted scores on tests requiring the ability to process relatively unfamiliar, typically nonverbal, information in novel ways. Although the etiology of these deficits remains unclear, there is a possibility that they are secondary to mild brain damage that develops as a consequence of multiple episodes of serious hypoglycemia early in life.

Adolescent↗
PubMed1984

Alcohol consumption and premature aging. A critical review.

Research conducted during the past ten years has demonstrated that alcoholics resemble yet older nonalcoholics on a variety of behavioral, radiological, electrophysiological, and regional blood flow measures of brain function. These similarities have led to speculation that excessive alcohol consumption causes a premature aging of the brain that, in turn, is responsible for the characteristic structural and functional changes seen in detoxified alcoholics. In this chapter, we discuss some of the conceptual and methodological problems associated with what has become known as the premature-aging hypothesis and review a series of recent studies that have used neuropsychological, computerized-tomography, and evoked-potential techniques to test its validity. We conclude that there is very little compelling empirical support for this intriguing hypothesis and suggest that the neurobehavioral changes seen in alcoholics are merely the reflection of a diffusely distributed pattern of brain damage.

Aged↗
PubMed1983

Cognitive loss and recovery in long-term alcohol abusers.

The nature of the memory and visuospatial defects associated with chronic alcoholism, and the recovery of these functions, were investigated in a large group of alcoholic men and well-matched nonalcoholic controls. Both young and old alcoholics displayed significant impairments on tasks requiring the learning of novel associations and the holding of information in memory over longer delay intervals. The recovery of cognitive skills was found to depend on the length of abstinence and the particular behavioral functions examined. Whereas psychomotor skills and short-term memory improved significantly with prolonged abstinence, long-term memory was impaired even after seven years of continuous sobriety. We propose that recovery of short-term memory reflects reestablishment of cortical functioning, while the persistent long-term memory defect indicates more permanent damage to diencephalic structures.

Alcohol Drinking↗
PubMed1983

Critical review of international standards for respiratory protective equipment - I. Respiratory protective equipment for particulate-laden atmospheres.

The standards for respiratory protective equipment (R.P.E.) from eleven countries and standards organizations were grouped according to type as particulate removing, gas and vapor removing, airline (fresh air hose and compressed air types), and self-contained breathing apparatus (open circuit and closed circuit). Each group of standards was further divided into specification and performance requirements. This paper is one in a series of three that highlights and critically reviews international respirator standards; it deals specifically with R.P.E. for protection against particulate-laden atmospheres. Great Britain, Australia, European Committee for Standardization (CEN), France, South Africa, Italy, Spain, New Zealand, Scandinavia, Japan, and Germany have standards for R.P.E. against particulate-laden atmospheres. Tabular summaries and accompanying discussion of national requirements are presented in the following categories: solid and liquid aerosol removal efficiency, clogging, and rough usage. Large differences and some notable omissions exist among standards. For example, the protection capacity of the filter can be tested by using solid particulate or liquid challenge aerosols. The majority of the countries evaluate protection capacity using solid particulate aerosols, while the remainder use both solid and liquid or liquid aerosols only. Other differences in filter testing deal with the composition of the test aerosol and the characteristic of the filter measured. The initial penetration or the penetration of the filter as it is being loaded over a specified period of time can be measured. In the latter case penetration is averaged over the test period and the degree of protection is assessed only for that overall time period; information is not provided concerning the protection afforded by the filter in the earlier stages of use.

Aerosols↗
PubMed1981

Effective heat strain index using pocket computer.

An effective heat strain index (EHSI) using a hand calculator with memory is suggested for on-site evaluation of prevailing hot ambient conditions. The inputs to the programmed calculator include dry-bulb, wet-bulb and globe temperatures, and estimates of metabolism and air movements. The index is based on a program for calculation of the total heat balance and on the efficiency of sweating. The display of information on the ambient conditions EHSI display is one of following: no strain; low strain; high strain; or time limits of exposure.

Body Temperature↗