Showing papers by "Saint Louis University published in 1978"

Minors' consent to treatment: a developmental perspective.

Abstract: This article discusses the cognitive and behavioral characteristics of minors in relation to the question of competence to consent to treatment. The legal standard (knowing, intelligent, and voluntary) that is used to judge the effectiveness of consent is translated into psychological concepts, especially cognitive abilities. Then a review of developmental psychological research examines these concepts as they relate to minors' abilities to satisfy the legal standard. It is suggested that cognitive developmental stages associated with ages below 11-13 years might exclude such minors from meaningful consent. In addition to cognitive considerations, certain results suggest that the tendency toward deference in early adolescence is so normative that capacity for voluntary consent is questionable through age 14. But existing evidence provides no psychological grounds for maintaining the general legal assumption that minors at age 75 and above cannot provide competent consent. Suggestions are made for further developmental and applied research focused on critical questions in the area of a minor's ability to consent.

Relaxation of Orthodontic Elastomeric Chains and Modules In Vitro and In Vivo

Abstract: Relaxation patterns for two orthodontic polyurethane-based elastics have been quantified in dry air and water bath environments and in vivo. Water bath simulation of in vivo behavior is apparently valid for up to a week following initial activation, but it becomes somewhat erroneous thereafter.

Antitrypanosomal effect of allopurinol: conversion in vivo to aminopyrazolopyrimidine nucleotides by Trypanosoma curzi

Abstract: The parasite Trypanosoma cruzi metabolizes allopurinol by a sequential conversion to allopurinol mononucleotide and aminopurinol mononucleotide. The latter is incorporated into RNA. This transformation of a widely used innocuous agent, allopurinol, into a toxic adenine analog appears to account for the antiprotozoan effect of allopurinol. These unique enzymatic activities appear to occur only in T. cruzi and the pathogenic lesihaminae. Allopurinol may serve as a model for the synthesis of similar antiprotozoan agents.

Nigrothalamic pathway in the cat demonstrated by autoradiography and electron microscopy.

Abstract: Light microscopic autoradiography and electron microscopy were used to trace the nigrothalamic projections and to study the sites of termination of this pathway in the cat. Injections of tritiated amino acids or electrolytic lesions were placed in the substantia nigra pars reticularis (SNr). An accumulation of radioactivity was found in the ventral medial nucleus and in the ventromedial part of the ventral anterior nucleus. At the ultrastructural level degenerating medium size synaptic boutons and medium size myelinated fibers were observed in these nuclei. The boutons contained clear pleomorphic vesicles and formed symmetrical type synaptic contacts with regular type dendrites and vesicle-containing dendrites.

In Vitro reconstitution of calf brain microtubules: Effects of macromolecules

Abstract: A comparative study has been carried out of the ability to reconstitute into microtubules of tubulins prepared by the Weisenberg and the cycle procedures. It was found that further purification of cycle tubulin by phosphocellulose chromatography made its ability to polymerize identical with that of Weisenberg tubulin. By adding to either tubulin the isolated proteins which copurify with tubulin in the cycle prodecure, it is possible to reduce their critical concentrations of microtubule formation to a value identical with that of cycle tubulin. It was demonstrated quantitatively that the effect of these nontubulin proteins could be mimicked by a variety of polycationic molecules, the most effective one being poly(L-lysine). A possible mechanism is described by which growing microtubules could be stabilized by subsequent addition of the nontubulin proteins. The conclusion is drawn that, at present, it is not known whether the proteins which copurify with tubulin are specific components of the microtubule system, or simply artefactually coprecipitated impurities.

Focal mechanism studies in the New Madrid seismic zone

Abstract: A recent study of seismicity in the New Madrid seismic zone by Stauder et al. (1976) has shown the existence of linear micro-earthquake patterns of up to 120 km in length. This study presents the results of composite microearthquake focal mechanism studies along these trends together with focal mechanisms obtained using long-period surface-wave data from larger events. Due to the present microearthquake array geometry, the composite focal mechanism studies do not indicate a complete picture of the nature of the earthquake processes for all the trends. However, the motion on the major 120-km long trend into northeastern Arkansas has significant components of right lateral fault motion. The consistency of surface-wave focal mechanisms and the composite focal mechanism along this trend indicates that it should be considered as a single tectonic unit.

Metabolic responses of the heart in acute myocardial infarction in man

Abstract: Acute myocardial infarction evokes a characteristic neurohumoral response: Catecholamine release is increased, plasma contents of free fatty acids and glucose are elevated and glucose tolerance is diminished. To what degree the myocardium participates in this stress response was evaluated by sampling coronary sinus and arterial blood in 50 patients with acute transmural infarction. Studies were initiated an average of 8 hours after the clinical onset of infarction and were continued for up to 60 hours. A total of 173 separate metabolic studies were analyzed. Forty-one percent exhibited a pattern of predominant myocardial free fatty acid uptake (mean extraction ratio 24 percent) in the presence of elevated plasma free fatty acid and glucose contents (respective means 1,181 μmol/liter and 210 mg/100 ml). Myocardial extraction ratios for glucose, lactate and pyruvate were low (respective means 1.1, 4 and 11 percent). Twenty-one percent of the studies revealed normal myocardial metabolism and 18 percent showed enhanced carbohydrate uptake, as evidenced by increased myocardial extractions of lactate and pyruvate (respective means 42 percent) and of glucose (mean 5 percent). Plasma contents of glucose and free fatty acids were lower than in the predominant free fatty acid group (respective means 156 mg/100 ml and 743 μmol/liter). The remaining 20 percent of studies showed high plasma substrate contents and low myocardial substrate uptake suggesting metabolic breakdown. The free fatty acid metabolic pattern was observed in more than 50 percent of the studies performed at the time of or close to the occurrence of important clinical complications. Propranolol, 0.1 mg/kg intravenously, shifted myocardial substrate utilization from free fatty acids toward carbohydrates. The myocardial respiratory quotient increased from an average of 0.79 to 0.88 ( P The study demonstrates that the metabolic patterns of the myocardium are influenced by the systemic response to stress. Beta adrenergic blockade changed substrate utilization of the myocardium, supporting the hypothesis that adrenergic activation plays an important role in these metabolic responses.

Vitamin K and gamma-carboxyglutamate biosynthesis.

Abstract: Publisher Summary This chapter discusses Vitamin K and γ-Carboxyglutamate Biosynthesis. Long periods of time may elapse between the discovery of a given vitamin deficiency disease, the isolation and structural analysis of the vitamin, and the final elucidation of its metabolic function. It is now established that vitamin K is part of a membrane bound carboxylase system and participates in the posttranslational carboxylation of selected peptide-bound glutamate residues in a number of vitamin K-dependent proteins. The requirements of this carboxylase system are reduced vitamin K, carbon dioxide, oxygen, and a suitable peptide substrate. The precise mechanism of the carboxylase reaction and the biochemical role of vitamin K are still unknown. It is now clear that vitamin K is also involved in an electron transport system in microsomes of mammalian organisms carrying out peptide-bound glutamate carboxylation. The chain involves NADH, vitamin K, and presumably oxygen as a terminal electron acceptor. The energy generated in this electron transport system is coupled in an as yet undetermined way to CO 2 fixation in glutamate. The intuitive belief that vitamin K should be involved in an electron transport system in expressing its procoagulant activity has been vindicated by recent work.

Control of the recruitment and firing frequencies of motor units in electrically stimulated muscles in the cat.

Abstract: Although the order by which motor units are recruited, and the frequencies at which they fire, vary during different types of exercise, laboratory studies involving the electrical stimulation of muscle have never examined the effect of different orders of recruitment on muscular function. This has been due, principally, to the lack of an adequate technique capable of selectively stimulating discrete populations of motor units in a muscle having a mixed population of fibres. The paper describes a computer-controlled stimulator and special electrode array which can control the pattern of motor-unit recruitment during electrical stimulation of the lower leg of the cat. In addition, following a program of recruitment analogous to that which is believed to normally occur during voluntary isometric exercise, the computer was able to sustain isometric muscular contractions to fatigue at a variety of tensions with almost identical endurance times. as are found in man.

Primary linitis plastica of the colon. Report of two cases and review of the literature

Abstract: Two cases of primary linitis plastica of the large intestine will be presented and discussed. Characteristic clinical features of this type of adenocarcinoma of the large intestine include younger age of presentation, low incidence of hepatic metastasis and a high incidence of ovarian, lymph node and peritoneal metastasis. Pathological features reveal thickening of the intestinal wall by diffuse infiltrating tumor cells of the characteristic signet ring cells, abortive glands and undifferentiated or anaplastic cells. The prognosis is poor.

A controlled study of the effect of oral contraceptives on migraine.

Abstract: Most patients do not discontinue the contraceptive pill because of minor cyclic migraine headaches. Physicians should determine which class of medication the patient is taking. Oral contraceptives may increase both the frequency and intensity of established migraine and sometimes also precipitate vasomotor or depression headaches. The incidence of headache varies from 0.2 to 60% depending on estrogen and progesterone ratio of pills. It might initiate headache in previously headache-free individuals. The incidence of attack is greater when the patient is beyond 30 years of age. Patients with the history of menstrual cycle longer than 28 - 30 days attack of migraine during the early trimester of pregnancy or during menstruation and parity influence the incidence of headache. A controlled study was conducted to observe headache frequency and index in migraine patients both on and off oral contraceptives with 20 patients in each category. Three distinct groups of patients were identified. One group improved while on the pill in a 2nd group headaches were aggravated by the pill and a 3rd group showed no influence of oral contraceptive on headache. Most women fell in the last two groups. Psychological factors play a role in the incidence of headache.

3-Oxo acid coenzyme A transferase activity in brain and tumors of the nervous system.

Abstract: THE ABILITY of the CNS to utilize the ketone body acetoacetate is dependent on its capability to form the corresponding CoA derivative (PAGE er a/.. 1971). The enzyme succinyl-CoA-3-oxo acid transferase (EC 2.8.3.5) is principally responsible for the conversion of acetoacetate to acetoacetyl-CoA (STERN et a/.. 1956). The formation of acetoacetyl-CoA appears to be quite important to the CNS, because exogenous acetoacetate and the other major ketone body. 3-hydroxybutyrate. are major carbon sources for energy production (HAWKINS er a/.. 1971; WILLIAMSON & BUCKLEY. 1973; DEVIVO et al., 1975) and lipid synthesis (WENG et a/.. 1973: DEVIVO et a/.. 1973; EDMOND, 1974; PATEL rr a/.. 1975: RAMSEY, 1976; PATEL & OWEN, 1977) in this tissue. particularly during the developmental period. Although CoA transferase has been shown to have a mitochondrial synaptosomal subccllular localization in the CNS (DEVIVO t't a!.. 1976). neural cell-specific activities have not been previously determined. Whole brain activity of the CoA transferase in the adult rat has been found to be approx 14\"\" of that of kidney, the organ of greatest activity (FENS~LAU & WALLIS. 1974). With regard to neoplastic tissue, F E N S ~ L A ~ et a/. (1975) have demonstrated that CoA transferase activity is present in hepatomas but not normal liver. A positive correlation was shown in these tumors between increased malignancy and increased enzyme activity. The mitochondial localization of the enzyme suggested that the acetoacetate was being used for increased energy production (FENSELAU et a/.. 1976). Since the CNS can normally utilize ketone bodies. including acetoacetate. we sought to establish if this ability was enhanced in tumors of the nervous system.

Isometric tension from rotary stimulation of fast and slow cat muscles.

Abstract: In cats anesthetized with alpha-chloralose, different populations of motor units in soleus, plantaris, and medial gastrocnemius muscles were stimulated in rotation through surgically divided groups of ventral roots. As a result, smooth muscular contractions were obtained at low frequencies of rotary stimulation, and maximal tetanic tensions were induced at frequencies within the upper range of voluntary contractions. The frequencies necessary to induce maximal tetanic contractions were lower for slow-twitch muscles than for fast-twitch muscles. It is speculated that the primary benefit resulting from asynchronous stimulation of the muscles is in the engagement of the tendon, which permits motor units to exert their tension without having to overcome a major portion of the elastic damping.

The calcium transport of sarcoplasmic reticulum.

Abstract: The sarcoplasmic reticulum is a key element in the regulation of the contraction-relaxation cycle in skeletal,1,2 cardiac? and smooth4 muscles. Less extensively developed but functionally analogous systems in nonrnuscle cells may play a similar role in the modulation of cytoplasmic movement^,^ secretory functions,? and the activity of Ca2+-dependent enzyme systems. The extent of homology between the intracellular Ca\" pumps and the ATP-dependent Ca2+ pumps of surface membranes' is unknown.

Antiestrogen Modulation of the Salt-Resistant Nuclear Estrogen Receptor*

Abstract: Studies were performed in vivo to determine the ability of the antiestrogen U-11.100A (UA) to modulate the binding of the estrogen receptor to uterine nuclei. UA (100 μg) injected at 30, 60, or 120 min into immature female rats arrested the rapid estradiol receptor complex (ERC) clearance from the nuclei after the 1-h accumulation which normally occurs after a single 5-μg injection of 17β-estradiol (E2). The UA receptor complex was then accumulated in the nuclei and retained for at least 48 h. As there is no indication that there is any significant replenishment of the cytoplasmic estrogen receptor within the first 12 h after a UA (100 μg) injection or after an E2 (5 μg) injection followed by a subsequent UA (100μg) injection at 30, 60, or 120 min, the UA appears to be recapturing estrogen receptors initially translocated to the nuclei. However, by 24 h after a UA injection, there is replenishment of the cytoplasmic estrogen receptor, and subsequent E2 injections at this time will cause the nuclear transl...

Prostaglandin Levels in Avian Blood and Reproductive Organs

Abstract: A radioimmunoassay with a sensitivity of 5 pg/assay tube was established to measure prostaglandins E, F, and A in avian plasma and tissues. Compared to plasma values when no egg is present in the uterus (shell gland), PGE but not PGF or PGA levels were significantly higher in hens in which an egg was present (P<0.001). However, in the various segments of the oviduct as well as in the lung, PGF levels were 2-8 times higher than PGE levels. In the plasma of laying Japanese quail hens, both PGE and PGF (but not PGA) levels were significantly higher than in birds that ceased to lay. Relatively high PGE concentrations were found in turkey hens during the day (855 pg/mi), and these increased significantly in the evening (1310 pg/mI). Prostaglandin levels in the plasma of roosters were generally lower than in hen plasma. Similarly, concentrations in the testes were considerably lower than those found in ovaries. It is suggested that, in the domestic hen, E prostaglandins are involved not only in promoting oviposition (as previously proposed) but also in mobilizing calcium from skeletal stores during the hours of intensive shell formation.

Transverse myelitis in mixed connective tissue disease

Abstract: Neurologic disease is reported to occur in just 10% of patients with mixed connective tissue disease (MCTD). Most commonly, this is manifested by mild trigeminal neuralgia. This report details the clinical and neuropathologic findings of transverse myelitis in a patient with MCTD. Neurologic features include progressive areflexic paraplegia with loss of bowel and bladder function. Neuropathologically there was thinning of the thoracic cord, widespread loss of axons and myelin sheaths, reactive astrocytosis, macrophage formation, vascular thickening with perivascular chronic inflammatory cell infiltration, and calcium deposits. This case demonstrates that severe neurologic disease unresponsive to therapy can occur in MCTD.

Bile acids LVII. Analysis of bile acids by high pressure liquid chromatography and mass spectrometry.

Abstract: Several high pressure liquid chromatographic methods for the separation of conjugated and free bile acids are presented. A mixture of synthetic conjugated bile acids has been separated by reverse-phase systems consisting of either a Waters Associates’ “fatty-acid analysis” or a μBondapak/C18 column eluted with a mixture of 2-propanol/potassium phosphate buffer (pH 2.5 or 7.0). The major conjugated bile acids present in the gallbladder bile of obese subjects have been analyzed each in less than 30 min and quantitated with a U.V. detector set at 193 nm. Some of the 5α- and 5β-isomers of conjugated bile salts could be resolved in straight-phase systems on Corasil II or μPorasil columns. Mass spectra of the conjugated bile acids obtained by electron impact were characteristic of the type of amino acid attached to the side chain, and the number of hydroxyl substituents on the nucleus. Most of the isomers could readily be differentiated by the relative intensities of the fragment ions.