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Biomedical subjects

R C Hall

Publications and source records attributed to R C Hall.

At least 55 records · Page 3Linked to original sources
PubMed1991

Evaluation of a simple weight-loss method for determining the permeation of organic liquids through rubber films.

The standard ASTM method for determining permeation of liquid penetrants through polymeric films (F739-85) was compared with a simple weight-loss method. The weight-loss permeation cell was constructed of off-the-shelf components, a conventional analytical balance was used to measure the weight loss, and a chamber with continuous ventilation was used to hold the cell at constant temperature and evacuate the permeating penetrant. The advantages and limitations of the weight-loss method were illustrated by using data obtained from the permeation of acetonitrile, n-hexane, and methanol through films of four acrylonitrile-butadiene copolymers. The steady-state flux obtained by using the weight-loss method gave results statistically equivalent to the more analytically complex ASTM standard method. The weight-loss method required the experimenter to monitor the weight of the cell and its contents over time to obtain the steady-state flux whereas the ASTM method required the experimenter to chemically analyze for the penetrant concentration in the effluent gas stream as a function of time. The ASTM method required more analytical skill and training and more costly analytical equipment than did the simple weight-loss method. The weight-loss method needs further improvement and validation but shows promise even in its present form. By using the weight-loss method, the potential exists for far more chemical protective clothing users to conduct their own low-cost permeation testing as an initial screening to determine the relative permeation performance of candidate protective clothing materials. The weight-loss method is not meant to replace the standard ASTM method but to supplement it as a screening test.

Evaluation Studies as Topic↗
PubMed1990

Ammonia and ethylene oxide permeation through selected protective clothing.

An automated permeation test system was developed to collect permeation data. Three test specimens were evaluated simultaneously versus a challenge gas. The study evaluated chemical protective clothing garment materials for use by emergency response personnel confronted by ammonia or ethylene oxide in the gas phase. A total of 13 encapsulating suit materials and 2 glove materials were tested. Surgical latex material is not recommended for use in handling ammonia or ethylene oxide; other materials offer much greater protection.

Ammonia↗
PubMed1989

Physical illness encountered in patients with eating disorders.

Careful evaluation for medical illness with a severity rating scale of 276 eating-disorder patients admitted to hospital revealed that patients with anorexia and bulimia were at risk for developing medical complications. Severe cardiovascular complications were most likely to occur in eating-disorder patients who were also diuretic and/or laxative abusers. Forty percent of patients with bulimia had significant medical complications. The findings suggest that a medical work-up should be carefully undertaken in both anorexic and bulimic patients admitted to hospital. A mixed history of severe anorexia nervosa alternating with periods of bulimia was most likely to lead to severe life-threatening illness. Seventy percent of the bulimic patients admitted required some medical treatment. Five percent were considered severely medically ill, while 34% suffered from a significant medical disorder. Ten percent of patients with restrictive anorexia or anorexia alternating with binge/purge required intensive care unit (ICU) placement. Most illnesses requiring medical treatment were unknown to the patient and the patient's physician at the time of admission.

Anorexia Nervosa↗
PubMed1989

Sexual abuse in patients with anorexia nervosa and bulimia.

Few studies have documented the extent and nature of sexual abuse among women who later come to treatment for anorexia nervosa or bulimia. This comparison study reports on a sample of 158 patients admitted to an eating-disorder unit, of whom 60 gave a history of sexual abuse, compared to 98 with no history of abuse. Fifty percent of the anorexic and bulimic patients had suffered sexual abuse, compared to only 28% of patients admitted with other eating-disorder diagnoses; this was a significant difference (p less than 0.001). Of the four types of abuse surveyed, only those patients suffering rape were likely to have sought help from caregivers prior to admission (p less than 0.001). The authors report on likely perpetrators of abuse, age of first abuse, and frequency of depressive symptoms in the abused population. The data from this study strongly suggest that the possibility of sexual assault or abuse must be assessed and the results included in a comprehensive therapy plan for eating-disorder patients.

Adolescent↗
PubMed1989

Mitral valve prolapse and anxiety disorders in patients with anorexia nervosa.

Much has been written about the occurrence of mitral valve prolapse among eating disordered patients. Despite this literature, a causal relationship between the two conditions has yet to be established. The present study evaluated 500 patients with eating disorders and demonstrated an association between a low median ideal body weight and the frequency of mitral valve prolapse (P less than 0.001). The physical signs and symptoms of mitral valve prolapse disappeared in eating disordered patients with the return of normal weight (P less than 0.001). Contrary to prior reports, there was no association between mitral valve prolapse and the occurrence of diagnosable panic or anxiety disorders. The results of this study suggest that the symptoms of anxiety and panic associated with mitral valve prolapse in eating disordered individuals may be due to physiologic change in cardiac status related to weight rather than central nervous system changes associated with classic anxiety disorders.

Adolescent↗
PubMed1989

Sexual abuse in patients with eating disorders.

The incidence of sexual abuse in eating disorder patients appears significant. Fifty percent of both our anorectic and bulimic patients reported a history of sexual abuse while only 28% of a non-anorexic, non-bulimic control population reported similar problems (p less than 0.01). Several patterns of behavior seemed related to previous sexual assault. In one, the eating disorder was used to change the body image of the patient and therefore to provide a defense to future abuse. Other behaviors which occurred more specifically in bulimic women dealt with a projection of repressed anger toward male authority figures. Forty six percent of the bulimic women seen in our study exhibited some promiscuous behavior, using sex either as a gauge of their own self worth or as a means of punishing men. It is essential that sexual issues be addressed early in the treatment of patients with eating disorders. Disclosure is often difficult particularly in outpatient situations where the patient lives at home with her family. It usually does not occur in such cases until the later stages of therapy, or until the patient is hospitalized. Rape is the exception since our data suggests that it is usually revealed early in the course of treatment (p less than 0.001). Once disclosure occurs, a dramatic change is usually seen in the patient and treatment becomes more effective. As the patient deals with the issues of sexual abuse, they no longer need to deny their sexuality or punish themselves or others. Issues of guilt, depression, repressed anger, low self-esteem, social isolation and inadequacy are important and need to be addressed during the course of therapy with sexually abused patients.

Adolescent↗
PubMed1989

Food and drug abuse: the contrasts and comparisons of eating disorders and alcoholism.

The authors present a series of comparisons highlighting the similarities and differences between alcoholism and two eating disorders: anorexia nervosa and bulimia nervosa. They suggest that diagnostic, psychodynamic and therapeutic similarities are strong and may relate to a common lack of behavioral inhibition once abnormal drinking or eating patterns become set. They point to recent research suggesting that eating disorder patients are at greater risk for alcoholism later in life. They conclude that a scientific comparison of these disorders may yield new research findings that could advance treatment methods for both types of psychopathology and may prevent later morbidity for the eating disorder group.

Alcoholism↗