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Biomedical subjects

N A Scott

Publications and source records attributed to N A Scott.

123 records · Page 7Linked to original sources
PubMed1984

Tyrosine prevents behavioral and neurochemical correlates of an acute stress in rats.

Exposure of rats to an acute, uncontrollable stressor can increase brain norepinephrine (NE) turnover and decrease locomotor and exploratory behavior. We examined the ability of exogenous tyrosine, NE's amino acid precursor, to protect rats from developing these neurochemical and behavioral changes when stressed. Animals pretreated with saline or tyrosine (200 mg/kg, i.p.) were subjected to tail shock (15 v, 2 mA, 5 sec/30 sec) or to no shock during a 60-min period. Exposure to shock depleted NE and increased its turnover [as indicated by altered NE and 3-methoxy-4-hydroxy-phenylene-glycol sulfate levels (MHPG-SO4)] within the locus coeruleus, the hippocampus and the hypothalamus. Behavioral deficits were observed using measures of locomotion, standing on hind legs, and hole-poking in an open-field apparatus. Animals given tyrosine before shock displayed neither shock-induced NE depletion nor the deficits in locomotion and hole-poking; brain MHPG-SO4 levels tended to be greater than after shock alone. These observations suggest that the stress caused NE to be released from some neurons more rapidly than it could be restored by synthesis or reuptake, thereby impairing noradrenergic transmission and NE-dependent exploratory behaviors. Tyrosine administration presumably enhanced the transmitter's synthesis in stressed animals, thereby preventing both the neurochemical and the behavioral deficits.

Animals↗
PubMed1982

Assessment of depression among incarcerated females.

The use of the abridged BDI as a depression screening device for a sample of recently incarcerated adult female felons was explored, and the concurrent validity of the instrument was examined. The results indicated that the abridged BDI was a highly reliable measure which substantially and significantly correlated with the MMPI D scale, as well as other MMPI scales. In addition, individuals who tended to score high or depressed on the abridged BDI consistently described themselves on self-concept rating scales in the direction of low self-esteem and low self-worth. Substantial and statistically significant negative correlations were consistently observed between the abridged BDI and self-concept measures. Consistent patterns of relationships between the abridged BDI and MMPI, as well as between the abridged BDI and self-concept scales, emerged and were congruent with clinical descriptions of depression. The consistency and pattern of results added strong support to the concurrent validity of the abridged BDI.

Adult↗
PubMed1981

Influence of time of feeding on time of parturition in beef cows.

The influence of time of feeding pregnant beef cows on the timing of parturition was investigated. The results suggest that the distribution of calvings between 'day' and 'night' can be altered by time of feeding. The calculations, based on a small quantity of data, suggest that feeding at 22.00 would result in 79 per cent of cows calving between 06.00 and 22.00. On the same basis of calculation the traditional 09.00 time of feeding would result in 57 per cent of cows calving during the 'day' period. There appears to be some evidence that by feeding pregnant beef cows in the evening better supervision of calving with a smaller proportion of cows calving at night can be achieved.

Animal Husbandry↗
PubMed1981

Tyrosine administration decreases vulnerability to ventricular fibrillation in the normal canine heart.

Intravenous infusion of tyrosine (1, 2, or 4 milligrams per kilogram) for 20 to 30 minutes caused dose-dependent increases in the ventricular fibrillation threshold in normal dogs. Administration of valine, a neutral amino acid that competes with tyrosine for uptake at the blood-brain barrier, in a dose equimolar to the most effective dose of tyrosine, slightly decreased the ventricular fibrillation threshold when given alone and significantly blocked elevation of the ventricular fibrillation threshold after tyrosine infusion. Hence, tyrosine, presumably acting in the central nervous system, can protect against certain ventricular arrhythmias.

Animals↗
PubMed1980

The applicability of the Beall-Panton MMPI escape index to female felons.

Tested the discrimination capacity of the MMPI Beall-Panton escape (EC) index by applying it to a sample of 168 minimum security incarcerated female felons. The EC index did not differentiate significantly between escapee (N = 71) and non-escapee (N = 97) female felons. However, significant differentiation between the groups did occur when MMPI clinical and validity scales were considered separately. Escapees scored significantly higher than non-escapees on scales F, PD, PT, SC, and MA and significantly lower on scale L. In addition, female escapees were significantly younger and more often imprisoned as a juvenile than non-escapees. There were no significant differences between the two groups with respect to IQ, educational level, sentence length, or numbers of adult incarcerations, psychiatric hospitalizations, or children.

Adult↗
PubMed1980

Betaine Synthesis from Radioactive Precursors in Attached, Water-stressed Barley Leaves.

In wilted barley leaves, betaine accumulates at about 200 nanomoles per 10 centimeters leaf per day. Results with (14)C-labeled precursors were qualitatively and quantitatively consistent with de novo synthesis of this betaine from serine via ethanolamine, choline, and betaine aldehyde and indicated that water stress may increase the activities of all steps in this pathway except the last.Doses (1 micromole) of each (14)C-labeled precursor were supplied as droplets to the tips of attached, 10-centimeter, second-leaf blades of turgid and wilted plants, and the incorporation of (14)C into betaine was followed. From the rates of betaine labeling, estimates were made of the potential capacities (nanomoles per 10 centimeters leaf per day) for the methylation and oxidation steps. Labeling of betaine from [(14)C]choline, [(14)C]ethanolamine, and [(14)C]serine was about 7- to 10-fold greater in leaves wilted for 2 days than in turgid leaves, whereas label from [(14)C]betaine aldehyde appeared in betaine at about the same rate in both turgid and wilted leaves. In leaves wilted for 2 days, the potential capacities for converting [(14)C]ethanolamine, [(14)C]choline, and [(14)C]betaine aldehyde to betaine all approached or exceeded the rate of betaine accumulation (about 200 nanomoles per 10 centimeters leaf per day); in turgid leaves, only the potential for converting betaine aldehyde to betaine exceeded this rate. The rate of conversion of [(14)C]ethanolamine to betaine increased 4-fold after 6 to 10 hours of wilting, which was soon enough to account for the onset of betaine accumulation.

Journal Article↗
PubMed1980

A morphological and histological study of the postnatal development of intervertebral discs in the lumbar spine of the rabbit.

Some basic features in the development of the structure of the annulus fibrosus and nucleus pulposus in the rabbit, as described by previous workers, have been confirmed in the present study. However, the greater thickness of the anterior part of the disc, as compared with the posterior region, and the distinctive arrangement of lamellae in the posterior part of the disc, cannot be attributed, as conventionally claimed from studies of the human spine, to a secondary curvature in the lumbar spine associated with an upright posture: for these features are present in the lumbar spine of the quadrupedal rabbit with its primary curvature. Secondary ossification produces a plate-like epiphysis separating the growth cartilage from the intervertebral disc. A distinct cartilaginous plate, limiting the nucleus pulposus in the rabbit intervertebral disc, only becomes apparent when collagen fibres cease to traverse the area above and below the nucleus pulposus.

Animals↗
PubMed1979

Correspondence of the MMPI and MMPI-168 among incarcerated female felons.

This study was designed to assess the correspondence between the MMPI and MMPI-168 for a sample of adult incarcerated female felons. The results indicated a high degree of agreement, median correlation of .79, between corresponding validity and clinical scales of the MMPI-168 and the full MMPI. The MMPI-168 significantly overestimated scales L, F, and D, while it underestimated scales K, Hy, Pd, and Mf. Configural correspondence between the two instruments in terms of profile high points was somewhat less than has been reported for psychiatric populations. However, the MMPI-168 appeared to be a useful short screening instrument for incarcerated female felons with respect to accurate assessment of profile validity, configural correspondence to the full MMPI, and correlations between corresponding scales. Its utility in these respects far exceeds prior attempts to employ the Mini-Mult with a similar sample of incarcerated females.

Adult↗
PubMed1976

Correspondence of the MMPI and Mini-Mult among female reformatory inmates.

Comparison of the MMPI and Mini-Mult scales yielded significant scale-by-scale correlations. However, the group means were different in 6 of the 11 possible scales, and there was a general tendency for the Mini-Mult to over-estimate MMPI scales. The Mini-Mult proved to be highly ineffective to detect MMPI invalid profiles. In addition, agreement on profile configurations or high points and degree of pathology as indicated by number of significant clinical scale elevations was very poor. The results of this investigation are similar to the findings of Rybolt and Lambert (1975), as well as those of Platt and Scura (1972), and lead one to recommend that the Mini-Mult not be employed as a clonical assessment instrument with incarcerated adult female populations. Its multiple deficits make clinical use hazardous.

Adolescent↗
PubMedDate not supplied

Overview of therapies for prevention of restenosis after coronary interventions.

Coronary artery disease is a leading cause of morbidity and mortality in the United States and across the world. The economic impact of coronary artery disease is staggering and on the rise. Percutaneous transluminal coronary angioplasty is widely used to treat severe, symptomatic coronary stenosis. The Achilles heel of angioplasty is restenosis of those treated arteries. As a result, numerous therapies, including mechanical and pharmacological approaches, to prevent restenosis have been studied. A greater understanding of the pathophysiology of restenosis has enhanced the success of these therapeutic approaches. To date, the most important and successful approach to limit restenosis has been the use of coronary stents. Stents have reduced the rate of restenosis from approximately 50% down to 20-30%. However, in-stent restenosis presents a new and an even more challenging dilemma. The success of adjunctive drug therapy has been promising, but, as of yet, very limited. Antithrombotic agents have reduced acute thrombosis and many of the acute complications of angioplasty. New approaches and therapies are very encouraging, and provide great hope in the treatment of restenosis. Brachytherapy has shown success in the treatment of in-stent restenosis, and recently has been approved by the United States Food and Drug Administration for this indication. Drug-eluting stents using antiproliferative drugs are the most exciting new advance in preventing restenosis, currently in Phase III trials. Gene therapy, targeted drug delivery, and newer antithrombotic agents are also under investigation. We will review the pathophysiology of restenosis, animal models, pharmacological therapies, and mechanical approaches for the treatment of restenosis.

Animals↗
PubMedDate not supplied

Opiate and sedative dependence predicts a poor outcome for patients receiving home parenteral nutrition.

BACKGROUND: Home parenteral nutrition (HPN) is used to treat intestinal failure. A minority of HPN patients are dependent on opiates and benzodiazepines to control pain and anxiety. The aim of this study was to determine what effects such drug dependence had on patient outcomes. METHODS: Ten dependent patients were prospectively compared with 10 well-matched, nondependent HPN patients for the same 12-month period. Episodes of line sepsis and other complications were documented and the cost of treatment estimated. Health status was measured using the SF36 and EuroQol instruments. RESULTS: The dependent group had significantly more episodes of central line sepsis (p = .0007) as well as other complications (p = .0002). This led to significantly longer periods of inpatient care (p = .0004) and therefore higher costs of treatment. Health status was lower in the dependent group; they reported more pain (p = .04) and less energy (p = .04). CONCLUSIONS: The complication rate and increased cost of treatment for opiate- and sedative-dependent patients receiving HPN significantly detract from the overall outcome of this therapy.

Adult↗
PubMedDate not supplied

Octreotide and postoperative enterocutaneous fistulae: a controlled prospective study.

Nineteen patients with postoperative enterocutaneous fistulae were randomised, in a double blind fashion, to receive either 12 days of octreotide (100 micrograms tds) by subcutaneous injection or 12 days of placebo injections. Fistula output for 7 days before and during all 12 days of treatment was recorded for each patient. Fistula losses before entering the trial were similar for both the placebo group (n = 8; range of daily medians: 202 mls to 400 mls) and the group of patients randomised to receive octreotide (n = 11; range of daily medians: 252 mls to 550 mls). There was no significant difference in fistula output between the two groups of patients while receiving either 12 days of placebo injections or 12 days of subcutaneous octreotide therapy. Fistula closure, defined as no fistula output for 2 successive days during the 12 days "therapy" period, was seen in only 1 patient given octreotide and in 3 patients given the placebo. In a double blind prospective study of 19 patients with enterocutaneous fistulae, octreotide therapy was neither associated with a significant reduction in fistula losses nor an increased rate of spontaneous fistula closure.

Adult↗