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Biomedical subjects

K Altman

Publications and source records attributed to K Altman.

At least 37 records · Page 2Linked to original sources
PubMed1980

Suppression of self-injurious behaviour: determining the least restrictive alternative.

In keeping with recent ethical and legal guidelines regarding the use of aversive treatment procedures, a number of alternatives for the treatment of self-injury have been suggested. The present study provides an example of the determination of the least restrictive but most effective treatment with a case of self-injury. Employing a combination of multiple baseline and reversal designs, the effects of DRO, overcorrection, lemon juice, and aromatic ammonia on the rate of self-poking in a profoundly retarded child were examined. DRO and overcorrection were both ineffective. Although lemon juice suppressed and stabilised the rate of poking, aromatic ammonia produced greater suppression. Implications for the testing of treatments for SIB are discussed.

Behavior Therapy↗
PubMed1979

Effects of the Feingold diet on seizures and hyperactivity: a single-subject analysis.

The effects of a dietary manipulation on seizure frequency and activity level of a 3 1/2-year-old male with tuberous sclerosis, mental retardation, and uncontrolled seizures were assessed. Using a reversal design, the Feingold (K-P) diet was presented and withdrawn three times, while the medication regimen remained unaltered. Every application of the K-P diet resulted in substantial reductions in seizure frequency. During a 21-week follow-up, seizure frequency remained low despite the phasing out of one drug, and seizures were reportedly eliminated 1 year later. Brief objective measures of hyperactivity failed to show any effect due to the diet changes.

Child, Preschool↗
PubMed1978

Behavioral treatment of obesity in patients with Prader-Willi syndrome.

Self-monitoring combined with contingency contracting resulted in weight loss, modification of dysfunctional eating habits, and increased or sustained exercise rates for two obese, mentally retarded adolescent females with Prader-Willi syndrome. Contingency contracting between clients and their parents/caregivers was used to specify consequences for daily self-monitoring, reduced caloric intake, weight loss, and exercise. Punishment for food stealing was also employed. Results suggest that contingency contracting is an effective technique for producing long-term weight loss in obese mentally retarded adolescents. Further, these techniques offer an alternative to the clinician considering solely dietary restriction or surgical intervention.

Adolescent↗
PubMed1978

Effect of progestins on androgen delta4-3-ketosteroid-5alpha-A-ring reductase system in rat oral mucosa.

Rat oral mucosa microsomal delta4-3-ketosteroid-5alpha-A-ring reductase enzyme system, reducing testosterone and 4-androstenedione, was found to be inducible by systemic administration of medroxyprogesterone acetate (MPA). MPA, when used in a mixture with testosterone and/or 4-androstenedione in vitro, acted as a competitive inhibitor of the reduction of these substrates.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1977

Establishing walking by severely retarded children.

This article examines the implications of independent ambulation for severely retarded children and reviews the literature describing behavioral interventions which facilitate walking. Findings from applied behavior analysis of single subjects support the value of operant techniques in the acquisition of walking. An operationally defined, data-based, four-level sequence for training walking beginning with momentary standing and ending with independent walking on command is described. Representative data from five severely retarded children are presented.

Behavior Therapy↗
PubMed1977

Specific glucocorticoid receptor in the iris--ciliary body of the rabbit.

The cytoplasm of the iris--ciliary body of the rabbit contains a receptor capable of specifically binding dexamethasone. This binding protein has a high affinity for dexamethasone (average KD = 2.0 X 10(-8) M), a low capacity (average 4.8 X 10(-13) mol of steroid bound per milligram of protein), and extreme heat sensitivity; it exhibits a pattern of competition virtually identical to that obtained with glucocorticoid receptors from other tissues and shows characteristic physicochemical behavior in various salt concentrations. The demonstration of a specific dexamethasone receptor in the iris--ciliary body provides the first direct biochemical evidence that these tissues may function as a target organ for glucocorticoids.

Animals↗
PubMed1976

Effect of alcohol (ethanol) administration on sex-hormone metabolism in normal men.

To determine whether ethanol per se affects testosterone metabolism, alcohol was administered to normal male volunteers for periods up to four weeks, resulting in an initial dampening of the episodic bursts of testosterone secretion followed by decreases in both the mean plasma concentration and the production rate of testosterone. The volunteers received adequate nutrition and none lost weight during the study, which tended to exclude a nutritional disturbance as the cause of the decreased testosterone levels. The changes in plasma luteinizing hormone suggested both a central (hypothalamus-pituitary) and gonadal effect of alcohol. In addition, alcohol consumption increased the metabolic clearance rate of testosterone in most subjects studied, probably owing to the combined effects of a decreased plasma binding capacity for the androgen and increased hepatic testosterone A-ring reductase activity. These results indicate that alcohol markedly affects testosterone metabolism independently of cirrhosis or nutritional factors.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1976

Prolonged ethanol consumption increases testosterone metabolism in the liver.

Male alcoholics often suffer from features of hypogonadism related to abnormal metabolism of sex steroids. Since the activity of testosterone reductases is rate limiting for testosterone metabolism in the liver, the effect of prolonged ethanol consumption by rats and human volunteers on the activities of these microsomal and cytosolic enzymes was studied. In rats, long-term ethanol ingestion doubled microsomal 5alpha-testosterone reductase activity, a major pathway for testosterone metabolism, while in human volunteers the activity was increased two- to fivefold. These changes may play a role in the altered androgenic activity of the chronic alcoholic.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1976

Steroid metabolism in ocular tissues of the rabbit.

The metabolism of cortisol and other steroids was studied in normal untreated rabbit iris-ciliary body and cornea as part of an investigation into the mechanism of glucocorticoid-induced glaucoma. Cortisol is readily converted to the inactive metabolite cortisone by these eye tissues indicating the presence of an 11beta-oxidoreductase system. This reaction is reversible with cortisone being converted to cortisol in the presence of appropriate cofactor. However, due to the absence of a (or as yet undetectable) cortisol-A-ring-reductase system (rate-limiting reaction) the steroid is not irreversibly metabolized to biologically inactive compounds. The 11beta-oxidoreductase system readily converts other C21-11beta-hydroxysteroids, such as corticosterone, to its appropriate C21-11-ketosteroid (11-dehydrocorticosterone). Some C21-steroids lacking the 11-hydroxyl group (11-deoxycortisol, 11-deoxycorticosterone) remain virtually unmetabolized (exception to this was found with progesterone). Evidence of a C21-steroid A-ring reductase system was found only when cortisone and progesterone were used as substrates. However, testosterone a C19 steroid was converted to clearly identifiable A-ring reduced and 17beta-and 3alpha(beta)-oxidoreduced metabolites, thus indicating the presence of testosterone A-ring reductase, 17beta-and 3alpha(beta)-oxidoreductase systems in the eye tissues studied. The presence of a steroid 5alpha(beta)-reductase for some steroids but not for cortisol indicates a distinct substrate specificity for this enzyme system in the eye tissues.

Androstenedione↗
PubMed1972

Hydrocortisone induction of rat-liver leucyl-transfer RNA and its synthetases.

Within 3 hr after the intraperitoneal administration of hydrocortisone to female rats, a new leucine-accepting tRNA and a new leucyl-tRNA synthetase activity appear in the liver cytosol. The new isoaccepting tRNA can be acylated only with the synthetase derived from livers of hormone-treated animals. Both components are transient; by 12 hr after hydrocortisone administration, the isoaccepting tRNA and its synthetase disappear from livers of treated animals.

Amino Acyl-tRNA Synthetases↗