Preliminary report on psychiatric comorbidity in adolescent substance abusers.
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Adolescent↗
Biomedical subjects
E Marsh
Publications and source records attributed to E Marsh.
Bromocriptine antagonizes behavioral effects of cocaine in the rat.
Rats given cocaine or bromocriptine under conditions of low basal arousal showed dose-dependent increases of locomotor activity for less than or equal to 1 hours, followed by depression of activity that diminished gradually over the next 2 hours. Arousal was related biphasically to dose (maximum at ca. 5 mg/kg) but depression increased monophasically with the dose of either agent. Both behavioral arousal and depression induced by cocaine were antagonized by bromocriptine, even at doses lacking behavioral effects alone (ID50 = 1.0 and 0.36 mg/kg [1.3 and 0.5 mumol/kg], respectively). Bromocriptine blocked depression of locomotion even when given after the initial stimulation by cocaine. Bromocriptine induced very weak stereotypy, and neither increased nor blocked stereotypy induced by cocaine or apomorphine. Cocaine, at maximally effective doses, did not deplete catecholamines or serotonin in brain regions at times of maximum behavioral arousal or depression, nor did bromocriptine after metabolic turnover of dopamine. Bromocriptine antagonized arousal induced by direct injection of dopamine into the nucleus accumbens. The ability of bromocriptine to block both the behavioral arousal and depression induced by cocaine may reflect activity of bromocriptine as a mixed agonist-antagonist with limited intrinsic agonistic activity at central dopaminergic D2 receptors, perhaps with particular reference to limbic mechanisms.
Animals↗
Automatic encoding of clinical narrative.
An experiment in the automatic encoding of English-language medical data is described. The encoding program has two stages. First, the free-text input is parsed and the information is arranged in a tabular format by a general-purpose natural language processor developed at New York University. Then a simple code-dependent subprogram assigns numerical values to the entries on the basis of the positions the input words occupy in the information format. Results of a blind test of the encoding program using the code employed at Roswell Park Memorial Institute for earliest symptoms of head-neck cancer are presented.
Data Collection↗
Influence of joint position on ankle plantarflexion in humans.
The contractile properties of the triceps surae (medial and lateral gastrocnemii and soleus) have been studied in humans. In comparison with most other human muscles, the triceps complex had a slow twitch (mean contraction and half-relaxation times 112.4 +/- 11.1 and 99.6 +/- 14.4 ms, respectively) and a low tetanus fusion frequency (60 Hz). Stretching the muscle caused both the contraction and half-relaxation times to become longer. With the knee bent, the optimum length for torque development corresponded to almost full dorsiflexion of the ankle. Similar results were obtained with the knee extended. The optimum position of the ankle differed considerably from the position of the joint when the leg was at rest. Although the position of the ankle joint affected electromyographic (EMG) activity recorded during maximal voluntary contraction, there was little change in the EMG-to-M wave ratio.
Adult↗
An experiment in automated health care evaluation from narrative medical records.
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Computers↗
Influence of joint position on ankle dorsiflexion in humans.
A method is described for investigating the contractile properties of the dorsiflexor muscles of the ankle. With the joint in the midposition the tibialis anterior was found to contribute less than half of the maximum voluntary torque, the remainder presumably being provided by the long extensors of the toes. The mean contraction and half-relaxation times of tibialis anterior muscles in healthy young men were 81.2 +/- 7.4 (SD) ms and 83.6 +/- 17.2 ms, respectively. When the tibialis anterior was stretched, the twitch became slower and more complete fusion of the contractions occurred during tetanic stimulation at low frequencies. Stimulation of tibialis anterior at 30 and 40 Hz disclosed that the optimum length of the muscle corresponded to about 10 degrees of plantarflexion. Maximum voluntary torque was also developed at 10 degrees of plantarflexion and decreased sharply as the ankle was dorsiflex beyond 5 degrees. The position assumed by the ankle joint at rest depended on whether the subject was sitting, standing, or lying, but was always greater, in the plantarflexed direction, than the "optimum" position for torque development. At low rates of stimulation the torque continued to increase throughout the full range of plantarflexion, probably because of the elasticity of the tendon. During maximum effort motoneuronal excitability did not appear to be influenced significantly by changes in joint angle.
Adult↗
Immunochemical evaluation of the organ specificity of prostatic acid phosphatase.
In a survey of normal and cancerous human tissues we determined the distribution of immunoreactive prostatic acid phosphatase, using rabbit antiserum to acid phosphatase purified from prostatic fluid. In all normal tissues and blood cells studied except leukocytes we found less than 0.1% (expressed as micrograms per gram of wet weight of tissue) of the quantity of immunoreactive prostatic acid phosphatase detected in normal prostate tissue by radioimmunoassay. A small quantity of cross-reactive antigen (2.5 microgram/10(8) cells) was found in leukocytes. In all normal and cancerous nonprostate tissues surveyed by an immunohistochemical technique we detected no immunoreactive prostatic acid phosphatase, except in kidney tissue. Faint but reproducible staining was detected in the lumen of distal tubules and collecting ducts and within interstitial capillaries. Immunoreactive prostatic acid phosphatase was detected in the urine of pre- and post-pubertal males and females. We propose that this material is from serum (low concentrations of immunoreactive prostatic acid phosphatase are present in the serum of men and women) and that it is excreted into urine by the kidneys. Full proof of this must await future experimentation. The specificity of our antiserum for prostatic acid phosphatase was demonstrated by the fact that the Mr 100 000 and 20 000 liver acid phosphatase isoenzymes did not cross with our antiserum in either the radioimmunoassay or double-diffusion analysis. Similarly, preparations of isoenzymes 5A and 5B are human serum albumin did not cross react.
Acid Phosphatase↗
Electrophoretic, kinetic, and immunoinhibition properties of gamma-glutamyltransferase from various tissues compared.
gamma-Glutamyltransferase (EC 2.3.2.2) from human liver, kidney, pancreas, and duodenum migrated in acrylamide gels (65 g/L) as a single band with the following decreasing order of electrophoretic mobility: liver > pancreas > kidney > duodenum. The initial velocity kinetic constants of pancreatic and duodenal gamma-glutamyltransferase and of the enzyme in human serum were determined and compared with those we previously established for the enzyme from human kidney, liver, and serum. The greatest differences were in the glycylglycine competitive-inhibition constants: kidney gamma-glutamyltransferase was the most strongly inhibited and pancreatic enzyme the second most strongly inhibited by high concentrations of glycylglycine, with the liver and duodenal isoenzymes only slightly inhibited and the enzyme in serum not inhibited over the concentration range (0-150 mmol/L) of glycylglycine used. Differences between the other kinetic constants of these isoenzymes were much smaller. Human liver gamma-glutamyltransferase was obtained in a highly purified form by a six-step procedure that included papain digestion of the original homogenate. Rabbit antisera raised against this preparation inhibited liver, kidney, and pancreatic gamma-glutamyltransferase activity equally well (78, 76, and 78% inhibition, respectively), but inhibited the hog-kidney enzyme only slightly (1%). We conclude that the polypeptide portions of the isoenzyme molecules are structurally similar but that the carbohydrate moieties differ significantly in structure and topography.
Duodenum↗
Studies of long-range density effects on the proliferation of 3T3 and RLCW cells in recirculated medium.
Swiss mouse 3T3 cells and rat liver-derived RLCW cells were grown in monolayers and perfused with culture medium. A flow-rate dependent increase in the growth rate was observed both by 3H-thymidine uptake and by a rise in cell numbers. The characteristics of the response were dependent on the recirculating volume and on whether serum was present in the culture medium. In RLC cultures perfused with serum-supplemented medium the growth promoting effect decreased with increasing density of the cells. In the absence of serum, recirculation of NCTC medium had no effect on RLCs but increased growth was observed in recirculated MEM. In 3T3 cultures, a linear response was observed over a limited density range in the presence of 10% serum-supplemented medium indicating that substances present in the serum substantially modify the behaviour of the monolayer to perfusion. In serum-free medium the effect of perfusion on 3T3 cultures was confined to a small density range and was consistent with the more rapid removal of a diffusible inhibitor from the pericellular environment by recirculating the medium. Treatment of the perfusing medium with immobilised proteinases (trypsin, chymotrypsin, protease) did not alter the response except in the presence of putrescine.
Cell Count↗
Triiodothyronine in rat submaxillary salivary gland: effects of altered adrenergic function.
To determine whether changes in adrenergic nerve terminal activity may influence tissue metabolism of iodothyronines, sympathetic nervous function of the rat submaxillary salivary gland was altered, and effects on salivary gland triiodothyronine (T3) uptake and retention measured. Following unilateral superior cervical ganglionectomy, denervated salivary gland contained 24% less (p less than 0.02) radioimmunoassayable T3/mg and took up 20% less (p less than 0.001) intravenously administered 125I-T3/mg than the contralateral innervated gland. Effects were similar at 7, 14 and 56 days following ganglionectomy and could not be accounted for by post-denervation changes in the delivery of the isotope, in total salivary gland water, in vascular volume or in extracellular or intracellular fluid spaces. When reserpine was administered to unilaterally ganglionectomized animals, uptake of 125I-T3/mg in the innvervated gland was reduced by 10% (p less than 0.005), relative to the denervated gland. The results suggest that loss or diminution of peripheral adrenergic nerve terminal activity reduces tissue uptake and retention of T3.
Animals↗
The changing health scene.
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Health Workforce↗
Preventing bicycle-related head trauma in children.
Although the majority of bicycle-related injuries and deaths could be prevented by the use of bicycle helmets, rates of helmet use in the United States remain well below Healthy People 2000's goal of 50% usage. Educational efforts to improve usage rates often fail to produce significant changes, in part because a child's understanding of risk plays only a small role in his or her decision to wear a helmet. To address the need for more effective injury prevention techniques, the authors propose a modification of the Health Belief Model, which is used by injury control experts to explain the various cognitive, social, and environmental factors that influence preventative health behavior. By incorporating the behavioral theory of self-efficacy in the structure of the Health Belief Model, trauma care providers and injury prevention specialists will be better able to design successful injury prevention programs that address key variables in health-related decision making.
Bicycling↗