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Biomedical subjects

R A Frank

Publications and source records attributed to R A Frank.

At least 37 records · Page 2Linked to original sources
PubMed1993

Adams-Oliver syndrome: cutis marmorata teleangiectatica congenita with multiple anomalies.

A 1-year-old female with the following multiple congenital anomalies is described: large vascular plaques on the scalp with atrophy and ulcerations, cutis marmorata and dilated veins on the trunk and extremities, short toes with partially missing phalanges and nails, retro- and micrognathia, strabismus convergens and atrial septal defect. These anomalies are characteristic of the Adams-Oliver syndrome, a rare autosomal dominant neuroectodermal syndrome which may be a maximal variant of van Lohuizen's syndrome (cutis marmorata teleangiectatica congenita).

Abnormalities, Multiple↗
PubMed1993

Both perceptual and conceptual factors influence taste-odor and taste-taste interactions.

Observers are often asked to make intensity judgments for a sensory attribute of a stimulus that is embedded in a background of "irrelevant" stimulus dimensions. Under some circumstances, these background dimensions of the stimulus can influence intensity judgments for the target attribute. For example, judgments of sweetness can be influenced by the other taste or odor qualities of a solution (Frank & Byram, 1988; Kamen et al., 1961). Experiments 1 and 2 assessed the influence of stimulus context, instructional set, and reference stimuli on cross-quality interactions in mixtures of chemosensory stimuli. Experiment 1 demonstrated that odor-induced changes in sweetness judgments were dramatically influenced when subjects rated multiple attributes of the stimulus as compared with when they judged sweetness alone. Several odorants enhanced sweetness when sweetness alone was judged, while sweetness was suppressed for these same stimuli when total-intensity ratings were broken down into ratings for the sweetness, saltiness, sourness, bitterness, and fruitiness of each solution. Experiment 2 demonstrated a similar pattern of results when bitterness was the target taste. In addition, Experiment 2 showed that the instructional effects applied to both taste-odor and taste-taste mixtures. It was concluded that the taste enhancement and suppression observed for taste-odor and taste-taste mixtures are influenced by (1) instructional sets which influence subjects' concepts of attribute categories, and (2) the perceptual similarities among the quality dimensions of the stimulus.

Adult↗
PubMed1993

Practice management education--are residency programs properly preparing physicians for the 21st century?

Several surveys indicate that third-year physician residents and recent graduates felt that their training in practice management skills was inadequate and that they felt unprepared in this area. This professional paper will present a discussion of residency education and the current complex health care environment. It will also describe a three-year comprehensive curriculum in practice management which can be incorporated into the programs.

Curriculum↗
PubMed1992

Cocaine euphoria, dysphoria, and tolerance assessed using drug-induced changes in brain-stimulation reward.

The time course of cocaine-induced changes in self-stimulation thresholds were used to evaluate cocaine euphoria and dysphoria as a function of the chronicity of drug treatment, dosage level, and the spacing of injections. It was assumed that cocaine-induced decreases in thresholds were indicative of cocaine euphoria, while increases in thresholds reflected rebound dysphoric responses to cocaine administration. Three experiments were performed using self-stimulating rats implanted with ventral tegmental area electrodes. Cocaine's threshold-lowering effects were evident 15 min postinjection (IP) with thresholds returning to baseline by approximately 3.0 h after treatment. Little evidence for cocaine-induced increases in thresholds was observed during periods of chronic cocaine treatment. However, thresholds were slightly elevated upon withdrawal from chronic cocaine treatment in Experiments 2 and 3. No evidence of tolerance or sensitization to cocaine-induced shifts in thresholds was noted with single daily injections, while multiple daily injections produced tolerance to cocaine's threshold-lowering effects. It is concluded that cocaine's ability to enhance brain-stimulation reward is highly reliable and robust, while decreases in brain-stimulation reward associated with chronic cocaine treatment are less reliable and difficult to demonstrate. The possible influence of drug dosage on the induction of cocaine dysphoria and the ability of various self-stimulation procedures to measure dysphoric effects are discussed.

Animals↗
PubMed1991

Cocaine's effects on rate of intracranial self-stimulation.

While some investigators have reported that cocaine increases response rates for brain stimulation reward, others have failed to demonstrate this effect. The present study was designed to evaluate the influence of stimulation parameters, dose of cocaine and operant-dependent response requirements on cocaine's ability to alter self-stimulation rates. Self-stimulation rates were collected on a minute by minute basis for 45 min following IP injections of 0, 5, 15 or 30 mg/kg cocaine HCI. All doses were tested using both nose-poking and lever-pressing operants. It was found that mean lever-pressing rates were significantly increased by 5 mg/kg cocaine, while nose-poking rates were significantly increased by 15 and 30 mg/kg cocaine. Further examination of the pattern of results indicated that the cocaine-induced increases in lever-pressing rate were mainly due to an increase in the time spent self-stimulating, whereas increases in nose-poking were mainly due to increases in nose-poking rate/min within self-stimulation bouts. It was hypothesized that 5 mg/kg cocaine increased lever-pressing by producing response perseveration, while the higher doses increased nose-poking mainly due to the compatibility of the nose-poking response topography with cocaine-induced stereotypies.

Animals↗
PubMed1991

Program planning and costing: a blueprint for success.

Intense competition and rapid technological changes have pressured the home care industry to respond to the need for new program and service line development. There is no secret to assured success. However, systematic planning to include identification of the program's purpose and objectives, market assessment, analysis of the program alternatives, resource needs and availability, and the impact of the program on the home care agency's market niche and financial state are all essential to facilitate successful implementation.

Cost Allocation↗
PubMed1991

Effects of thyroid status and fasting on hepatic metabolism of apolipoprotein A-I.

Metabolism of apolipoprotein (apo)A-I was studied in normal and chow-fed hyperthyroid rats, in 24-h fasted untreated male rats, and in rats after thyroparathyroidectomy (TXPTX). Rats were made hyperthyroid by administration of T3 (9.6 micrograms/day) or T4 (30 micrograms/day) with an Alzet osmotic minipump. Hyperthyroidism produced a similar two- to threefold elevation in plasma levels of apoA-I in male or female animals. During treatment with T3, plasma levels of T3 ranged from 200 to 400 ng/dl and did not correlate with plasma apoA-I levels. The net mass secretion and synthesis ([3H]leucine incorporation) of apoA-I by perfused livers from male hyperthyroid rats was elevated, while secretion of albumin was not different than that of euthyroid rats. Furthermore, the incorporation of [3H]leucine into total perfusate and hepatic protein was not altered by hyperthyroidism. The effect of thyroid hormone on apoA-I synthesis, therefore, does not appear to be a general effect on protein synthesis. After longer periods of treatment (28 days) with T3 (9.6 micrograms/day), hepatic apoA-I production decreased from that observed after 7 or 14 days of treatment, yet plasma apoA-I concentrations remained elevated. Plasma T3 decreased from 100 ng/dl to 40 ng/dl, in the hypothyroid rat resulting from TXPTX, but the plasma concentration of apoA-I did not change during the 2-week experimental period. The net secretion of apoA-I by livers from hypothyroid animals was depressed and albumin was uneffected compared to the euthyroid. Overnight fasting of euthyroid rats did not alter hepatic apoA-I secretion or plasma apoA-I levels, although under fasting conditions we had reported that hepatic output of apoB and E of VLDL is depressed. The addition of oleic acid to the perfusion medium, sufficient to stimulate VLDL production, did not affect net hepatic secretion of apoA-I by livers from euthyroid, hyperthyroid, or hypothyroid rats. In summary, hepatic synthesis of apoA-I appears to be controlled independently of other apo-lipoproteins and secretory proteins (albumin). Hepatic apoA-I synthesis is sensitive to thyroid status, increased in the hyperthyroid and decreased in the hypothyroid state. The specific stimulation of hepatic synthesis and secretion of apoA-I in the hyperthyroid state, however, tends to normalize over an extended period, perhaps from compensatory effects of a hormonal nature.

Animals↗
PubMed1990

Cocaine facilitates prefrontal cortex self-stimulation.

It has been demonstrated that cocaine HCl lowers thresholds for and increases rates of medial forebrain bundle intracranial self-stimulation. The influence of cocaine on prefrontal cortex self-stimulation was assessed in the present experiment. The prefrontal cortex was chosen because evidence indicates that the neuroanatomical and pharmacological substrate for intracranial self-stimulation at this site may differ from the substrate for medial forebrain bundle self-stimulation. Cocaine significantly decreased train-duration thresholds and increased the rate of prefrontal cortex self-stimulation. It was concluded that cocaine facilitates both prefrontal cortex and medial forebrain bundle self-stimulation, perhaps by influencing neural activity in the mesocorticolimbic dopamine system. However, the role of dopamine in cocaine's effects at both sites remains speculative.

Animals↗
PubMed1989

Chronic imipramine does not block cocaine-induced increases in brain stimulation reward.

Self-stimulating rats implanted with ventral tegmental area electrodes were tested with 15 mg/kg cocaine HCl before and after chronic imipramine treatment. Chronic imipramine had no influence on cocaine's ability to lower brain stimulation reward thresholds, suggesting that tricyclic antidepressant treatment does not block cocaine-induced euphoria.

Animals↗
PubMed1988

The effect of chronic cocaine on self-stimulation train-duration thresholds.

The effect of chronic cocaine treatment on brain stimulation reward was assessed by examining self-stimulation train-duration thresholds. Following a predrug, saline injection period, cocaine hydrochloride (10 or 15 mg/kg) was injected (IP) across 18 consecutive days of testing. Cocaine lowered thresholds across the entire period of drug administration, with the magnitude of cocaine's effect remaining stable during this time. The subjects returned to predrug, saline levels during a postdrug test conducted immediately following chronic cocaine treatment. In a final attempt to modify cocaine's effects, the subjects received 25 mg/kg cocaine HCl three times/day for three consecutive days. Subsequent testing at the original dosage levels revealed no change in the magnitude of cocaine's effect. It was concluded that cocaine's effect on brain stimulation reward does not show tolerance or sensitization with chronic use. Similar effects have been reported for morphine and amphetamine's effect on brain stimulation reward.

Animals↗
PubMed1988

The interactive effects of cocaine and imipramine on self-stimulation train-duration thresholds.

The present experiment examined the ability of the tricyclic antidepressant imipramine to influence cocaine's effect on intracranial self-stimulation. Following a predrug, saline injection period, cocaine hydrochloride (10, 20 or 30 mg/kg) was injected (IP) in 19 rats implanted with ventral tegmental area electrodes. Cocaine treatment uniformly decreased self-stimulation train-duration thresholds. In the next phase, the subjects were divided into two groups. One group received cocaine (as in the previous phase) and the other received cocaine plus imipramine (10 mg/kg, IP). Imipramine doubled cocaine's effect on self-stimulation train-duration thresholds. In addition, several other effects of cocaine (e.g., bradycardia, rear-limb dyskinesia) were potentiated by imipramine treatment. The results suggest that care must be exercised when treating cocaine abuse with tricyclic antidepressants since coadministration of these drugs intensifies cocaine's effects.

Animals↗
PubMed1987

The effect of operant and electrode placement on self-stimulation train duration response functions.

Multiple operants have been used to assess the effects of drugs on self-stimulation. It has typically been assumed that changing the operant used to obtain brain stimulation represents a simple performance manipulation. However, the validity of this assumption has been challenged by several research findings. The present study sought to clarify the role of response topography and slight differences in electrode placement on operant-induced shifts in self-stimulation thresholds and response rates. Thresholds and rates were determined for three operants (leverpressing, nosepoking and omnidirectional leverpressing) using two bilaterally placed electrodes. In addition, the response topographies used to perform each operant were evaluated. It was found that the relationship between the thresholds and rates produced by the operants was more dependent on the electrode placement than operant or subject-specific factors. The results of this experiment suggest that the characteristics of the stimulation site determine the relationship among different operants. This finding may be due to differences in the reward substrate or stimulation-induced behaviors activated at various brain loci.

Animals↗
PubMed1987

A systematic evaluation of the properties of self-stimulation train-duration response functions.

A series of experiments examined the characteristics of train-duration response functions and two statistics derived from these functions: train-duration thresholds and maximum rates. Train-duration response functions exhibited a steplike appearance. The slope of the train-duration curves was not influenced by either reward or performance manipulations, which suggests that the animals were not matching their response rates to changes in these factors along the steep part of the function. Substantial shifts in train-duration thresholds were observed following changes in the reward value of the brain stimulation, whereas maximum rates were affected by changes in factors such as response effort. The results of Experiments 1 through 6 demonstrate several similarities and differences between train-duration response functions and the reward summation functions generated with manipulations of stimulation frequency. The experiments described in this report provide convergent evidence for the validity of both of these approaches.

Animals↗
PubMed1985

Gustatory processing differences in PTC tasters and non-tasters: a reaction time analysis.

The present study examined differences in gustatory processing for tasters and non-tasters of phenylthiocarbamide (PTC) by assessing intensity judgment reaction times in these two groups. After prescreening for sensitivity to PTC, subjects were asked to judge whether solutions of sucrose, sodium chloride, quinine sulfate, hydrochloric acid and PTC were weak, medium or strong as quickly as they were able. Based on the reaction time and PTC sensitivity data, three groups of subjects were identified; tasters, sensitive non-tasters and less sensitive non-tasters. The taster population was characterized by their high sensitivity to PTC and a typical, negatively skewed distribution of reaction times. Sensitive non-tasters demonstrated a distribution of reaction times that was similar to that observed with tasters. However, these subjects were insensitive to PTC. The less sensitive non-tasters were insensitive to PTC and produced reaction times that were significantly slower than those produced for the other two groups across all of the substances tested. It is hypothesized that two groups of PTC non-tasters exist. One group has a specific deficit involving PTC and related compounds. The other group demonstrates sensitivity deficits for a wide range of gustatory stimuli.

Adolescent↗
PubMed1985

Both response effort and current intensity affect self-stimulation train duration thresholds.

Self-stimulation thresholds obtained from rate/intensity functions have often been used to measure brain stimulation reward (BSR) under the assumption that these indices are not contaminated by performance factors. However, very few studies have explicitly examined the effect of performance variables on thresholds. The present experiment examined the joint effects of response effort and current intensity on train duration thresholds. Three levels of stimulation current and lever weightings were factorially combined and train duration thresholds (defined as 50% of maximum response rates) were determined for each condition. It was discovered that changes in both current intensity and response effort produced shifts in thresholds, and that these shifts were of approximately equal magnitude. It was concluded that caution must be exercised when interpreting self-stimulation threshold data since, at least under some conditions, both reward (i.e., train duration) and performance (i.e., effort) manipulations produced similar shifts in self-stimulation response functions.

Animals↗