Showing papers by "University of Texas Medical Branch published in 1983"

Improved Classification of Anemias by MCV and RDW

Abstract: New automated blood cell analyzers provide an index of red cell volume distribution width (RDW) or heterogeneity and a histogram display of red cell volume distribution We have developed a classification of red cell disorders, based on mean corpuscular volume (MCV) or red cell size, heterogeneity, and histograms, to guide diagnosis from the peripheral blood analysis The distinction of iron deficiency anemia from heterozygous thalassemia or the anemia of chronic disease and the detection of early iron and folate deficiency is improved Red cell volume distribution histograms identify red cell fragmentation or agglutination, dimorphic populations, and artifactual counting of lymphocytes as red cells We recommend the use of these new variables in the initial classification of anemia by the practicing physician

Single neurones can initiate synchronized population discharge in the hippocampus

Abstract: The synchronized firing of neuronal populations is frequently observed in the mammalian central nervous system. The generation of motor activities such as locomotion and respiration requires the simultaneous activation of many neurones and synchronous firing also underlies the cortical alpha rhythm and the hippocampal theta rhythm. However the influence that single neurones may have on such neuronal population discharges is not clear. We have examined this question using small isolated segments of the CA3 region of the guinea pig hippocampus. We report here that in the presence of picrotoxin, a gamma-aminobutyric acid (GABA) antagonist, these segments spontaneously generate synchronized rhythmic bursts comparable with the interictal epileptiform discharges observed in the hippocampus and neocortex in the presence of penicillin. The activation of some individual neurones by intracellular current injection can partially entrain and reset the rhythm. The probability that a synchronized burst will follow stimulation of a single cell increases with time after a spontaneous synchronized discharge, suggesting that each population discharge is followed by a period of relative population refractoriness. A delay of 40-200 ms elapses between the activation of a single neurone and the synchronized discharge. We suggest that during this time activity elicited in one neurone spreads to other neurones through multisynaptic excitatory pathways and leads eventually to the participation of the whole population in a synchronous burst.

Establishment and characterization of an in vitro model system for human adenocarcinoma of the stomach

Abstract: Ten permanent clones derived from a single biopsy specimen of an untreated human adenocarcinoma of the stomach were established and characterized in vitro. Tissue culture growth properties, doubling times, plating efficiencies, growth fractions, cell cycle phase distributions, DNA indices, modal chromosome numbers, and ploidies were determined. Growth fractions were nearly 100%, and doubling times ranged from 23 to 37 hr. The plating efficiencies were generally high for tumor cells in culture, ranging up to 70%. Modal chromosome numbers varied from 45 to 48, with a wider range of variability in about 25% of the cells studied in each clone. In addition, the parent cell line (from which the clones were isolated) was shown to grow in athymic mice and to have the same histochemical and cytological characteristics as the specimen taken from the patient. It is important to characterize human tumor cells in vitro in this detailed manner, since they serve as excellent model systems for other studies involving the heterogeneous responses to drugs and radiation. The identification of mechanisms of drug sensitivity and resistance and the testing of drug and radiation combination treatment schedules in such in vitro systems can provide valuable insight into the design of clinical protocols for treatment of stomach cancer in humans.

A four-year follow-up of hyperactive boys with and without conduct disorder.

Abstract: A four-year follow-up of clinically selected hyperactive boys with and without associated conduct disorder investigated their outcome during early adolescence and was taken from a structured behavioural interview and standard psychological testing. Boys originally diagnosed as "purely" hyperactive continued to be inattentive and impulsive at follow-up, but showed very few aggressive and antisocial behaviours. Hyperactive boys who had earlier been undersocialized and aggressive continued to have problems with attention and impulsivity, were reported to be aggressive, noncompliant, egocentric, exhibiting antisocial behaviours and using alcohol. These findings suggest that antisocial and delinquent behaviour often reported in follow-up studies of hyperactive boys may be linked to childhood aggression and unsocialized behaviour, rather than the syndrome of hyperactivity.

The Role of Surgery in the Zollinger-Ellison Syndrome

Abstract: When the Zollinger-Ellison syndrome was first identified, total gastrectomy was proposed as the most effective treatment for the secretory manifestations of the syndrome. Recently, however, great enthusiasm has developed for medical treatment by means of H2-receptor antagonists. The authors have cared for 27 patients with the Zollinger-Ellison syndrome at The University of Texas Medical Branch in the past 12 years and have been pleased with the results of total gastrectomy, which was performed in 23 of the 27 patients (one patient refused operation and three patients had lesser gastric operations). Twenty-three patients underwent total gastrectomy with Roux-en-Y esophagojejunostomy. There were no operative deaths. Primary tumors were found in 17 patients, seven of whom also had metastatic tumors. No tumors were found in nine patients. Nine patients are dead; the actuarial survival rate for all patients was 75% at 5 years and 52% at 10 years. Eleven of the 27 patients had the multiple endocrine neoplasia I syndrome. Of the 18 survivors, only three have normal serum gastrin levels, and all three had extrapancreatic gastrinomas, one in peripancreatic lymph nodes, one in the liver, and one in a cystic tumor attached to the stomach. Nutritional results were good to excellent, with a mean postoperative weight loss of 14.7% (mean follow-up period was 45 months). The authors conclude that treatment of the hypersecretory problems of the Zollinger-Ellison syndrome by total gastrectomy is safe and dependable. Results compare well with those of long-term medical management, whose success is dependent upon serial favorable responses to a lifetime of repeated challenges.

Collaterals of spinothalamic cells in the rat

Abstract: Spinothalamic (STT) cells were investigated in the rat to determine the distribution of subpopulations with terminals in both the lateral and medial thalamus, the thalamus bilaterally, or the thalamus and the medullary reticular formation. Two or more retrogradely transported substances (fluorescent dyes, and/or horseradish peroxidase) were injected in each animal. Three combinations of injections were most commonly used: (1) injections of the medullary reticular formation and thalamus, (2) separate injections into each side of the thalamus, and (3) separate injections into the medial and lateral thalamus. The distribution of single labeled cells after each injection was compared with previously published results for rats. The distribution of cells which contained both tracers, double-labeled (DL) cells, was the focus of this study. An average of 15% of STT cells and 8% of spinoreticular cells projected to both the reticular formation and thalamus. However, only a small component of STT cells (less than 2%) projected bilaterally into the thalamus. Most DL cells were found in upper cervical segments. The laminar distribution of all three groups of DL neurons were similar. These cells were most often located in the reticulated part of lamina V and the intermediate zone, lamina VII. STT cells that had terminals in both the medial and lateral thalamus and STT cells with collaterals in the reticular formation were concentrated on the side contralateral to their terminals. These DL neurons provide an anatomical substrate for noxious stimuli to stimuli to activate the reticular formation and thalamus and/or specific sensory and intralaminar thalamus simultaneously.

Human lymphocyte production of immunoreactive thyrotropin

Abstract: Interferon-alpha inducers were previously shown to cause human lymphocyte production of a corticotropin (ACTH)-like peptide. Thyrotropin (TSH) was not produced under these conditions. In contrast, this report shows that a T-cell mitogen (staphylococcal enterotoxin A), which does not induce the ACTH-like peptide, caused human lymphocyte production of an immunoreactive (ir) TSH. Lymphocyte synthesis of the ir TSH was first detectable at 24 hr, peaked at 48 hr, and thereafter declined. NaDodSO4/polyacrylamide gel electrophoresis of intrinsically radiolabeled lymphocyte-derived ir TSH showed radiolabeled peaks at 80, 50, and 26 kilodaltons. These peaks presumably correspond to trimeric, dimeric, and monomeric TSH-like proteins, respectively. Acid treatment and reduction caused the ir TSH to migrate as a 14-kilodalton peak with a 12-kilodalton shoulder in a gel filtration column run in 6 M guanidine . HCl. Thus, the ir TSH seemed to be composed of subunits with molecular masses corresponding to those of the beta and alpha chains of human TSH, respectively. The ir TSH appeared to be glycoprotein because it bound to a concanavalin A affinity column. Taken together these data suggest that in addition to ACTH, human lymphocytes can also produce a TSH-like substance.

Dantrolene dose response in awake man: implications for management of malignant hyperthermia.

Abstract: Dantrolene sodium was administered intravenously to 12 adult volunteers to assess muscular and cardiopulmonary response. Pharmacokinetic results were obtained from whole blood drug concentration. Indirectly evoked thumb adduction was quantitated. Handgrip strength and subjective weakness score (10 e

Biochemical and Electrophysiological Characteristics of Mammalian Gaba Receptors

Abstract: Publisher Summary The identification of γ-aminobutyric acid (GABA) in the vertebrate central nervous system was made by Roberts and Frankel, Udenfriend, and Awapara. In the succeeding 30 years, data have accumulated to suggest that this amino acid may serve as one of the more important neurotransmitters in mammalian brain and spinal cord. While early work concentrated on characterizing the manner in which this substance is synthesized, catabolized, stored, released, and accumulated in brain tissue, in more recent years there has been a shift in emphasis to identifying and defining the synaptic receptor sites for GABA. There was skepticism about a neurotransmitter role for GABA prior to the discovery of agents capable of antagonizing, relatively specifically, the electrophysiological effects of this substance. During the past decade, the tempo of research on GABA transmission has increased dramatically. Evidence has been found to link alterations in GABA function with the symptoms of a variety of neuropsychiatric disorders. Discoveries have been made implicating GABA and its receptors in the mechanism of action of a variety of clinically effective agents, such as anxiolytics, hypnotics, muscle relaxants, and anticonvulsants. Knowledge in this area has advanced to a stage where it is now possible to design drugs that will rather selectively modify the GABA system. Many of these agents are currently undergoing clinical trials. This chapter discusses the results of recent biochemical and electrophysiological studies directed toward characterizing GABA receptors. Because of the rapid developments in this field, the chapter focuses on highlighting and discussing topics that represent some of the more exciting advances in this area.

Factor analysis of the WAIS and wechsler memory scale: An analysis of the construct validity of the wechsler memory scale

Abstract: The WAIS and Wechsler Memory Scale subtest scores of 256 neurologic and nonneurologic subjects were factor analyzed. The results supported the construct validity of the Wechsler Memory Scale as a measure of verbal learning and memory, attention and concentration, and orientation. Construct validity was not demonstrated for the Visual Reproduction subtest as a measure of visual memory. Suggestions are offered for future development and research on measures of visual memory.

Bowel-Bypass Syndrome Without Bowel Bypass: Bowel-Associated Dermatosis-Arthritis Syndrome

Abstract: • A recurrent, episodic illness that occurs in as many as 20% of patients who undergo ileojejunal bypass surgery for morbid obesity has been well characterized and includes inflammatory cutaneous lesions with a histologic appearance like that of neutrophilic vasculitis, a nondeforming polyarthritis, and other systemic manifestations. Current concepts of pathogenesis center on overgrowth of bacterial flora in the bypassed bowel segment with subsequent development of a circulating immune complex disease. We report, for the first time to our knowledge, an identical clinicopathologic syndrome in four patients who have not had jejunoileal bypass surgery. Each patient, however, had other gastrointestinal disease that we believe predisposed to this syndrome, possibly via circulating immune complexes with bowel-associated antigens. We propose the expanded term,bowel-associated dermatosis-arthritis syndrome, to incorporate these new cases. We believe that this is not a rare syndrome and that it is easily distinguishable from other types of cutaneous necrotizing vasculitis. (Arch Intern Med1983;143:457-461)

Rapid resetting of aortic baroreceptors in vitro

Abstract: Pressure-response characteristics of arterial baroreceptors (BR) were shown recently to be reset following a 15- to 20-min change in mean arterial pressure (MAP); the curves shifted in the directio...

Modulation of Candida albicans attachment to human epithelial cells by bacteria and carbohydrates.

Abstract: The effects of carbohydrates (mannose and dextrose). Escherichia coli 07KL. and Klebsiella pneumoniae on Candida albicans attachment to epithelial cells was studied. Dextrose had no effect on yeast attachment to epithelial cells. Conversely, mannose significantly decreased both yeast and piliated bacterial attachment (E. coli 07KL, heavily piliated K. pneumoniae) whereas having no effect on nonpiliated K. pneumoniae attachment to epithelial cells. The number of yeasts attaching to epithelial cells was enhanced by preincubation of epithelial cells with piliated strains of bacteria, whereas preincubation with nonpiliated strains of bacteria had no effect on yeast attachment. Scanning electron microscopy showed that piliated bacteria and yeasts were juxtaposed on the epithelial cell surface. These data suggest that certain piliated strains of bacteria can enhance C. albicans attachment to epithelial cells and that type 1 pili of bacteria can be a factor in the enhanced attachment of C. albicans to epithelial cells.

Kearns‐sayre syndrome with reduced plasma and cerebrospinal fluid folate

Abstract: A young woman with Kearns-Sayre syndrome and progressive central nervous system deterioration over 15 years had decreased plasma and cerebrospinal fluid folate levels while receiving phenytoin for a seizure disorder. A muscle biopsy showed a "ragged red fiber" myopathy with reduced muscle carnitine and mitochondrial enzymes. Computed tomographic brain scans showed cerebral white matter hypodensities and bilateral calcification of the basal ganglia. The mechanism for the folate deficiency and altered ratio of plasma to cerebrospinal fluid folate is unknown, but the deficiency may be responsive to replacement therapy.

Familial subtypes of childhood hyperactivity.

Abstract: On the basis of family history data we defined two subtypes of childhood hyperactivity: family history-positive (FH+), in which at least one biological parent of the child had a diagnosis in the antisocial spectrum; and family history-negative (FH-), in which neither parent had such a diagnosis. Whi

Prolonged, naloxone-reversible inhibition of the flexion reflex in the cat

Abstract: A long-lasting inhibition of the flexion reflex was produced by prolonged electrical stimulation of a peripheral nerve with high intensity and low frequency pulses in decerebrate and spinal cats. The flexion reflex in single active motor axons was recorded from filaments of the L7, Sl or S2 ventral roots. The reflex was elicited either by electrical stimulation of a cutaneous or mixed hind limb nerve or by natural forms of stimulation applied to the foot. A late flexion reflex discharge could be elicited by electrical stimuli that activated Aδ and C afferent fibres. Conditioning stimulation of the common peroneal or tibial nerve at a suprathreshold intensity for C fibers at a rate of 2 Hz for 15 or 30 min produced an inhibition of the flexion reflex late discharges which outlasted the conditioning stimuli. Maximum inhibition on average was to 40.1% and 42.7% of control reflex value in decerebrate and spinal cats, respectively. In decerebrate cats, the duration of inhibition varied from less than 10 min to over 1 h beyond the termination of the conditioning stimuli, depending on the unit (mean = 37.1 ± 13.2 min). However, inhibition lasted over 20 min for all units tested in spinal animals (mean = 38.3 ± 5.4 min). This long-lasting inhibition of the flexion reflex was reversed completely by systemic injection of naloxone hydrochloride (0.05 mg/kg). The long-lasting inhibition of the flexion reflex produced by peripheral nerve stimulation is discussed in relation to peripheral nerve stimulation produced analgesia.

Interaction between calcium ions and surface charge as it relates to calcium currents

Abstract: Calcium ions affect the gating of Ca currents Surface charge is involved but to what extent is unknown We have examined this, using isolated nerve cell bodies of Helix aspersa and the combined microelectrode-suction pipette method for voltage-clamp and internal perfusion We found that Ba and Sr currents produced by substitution of these ions for extracellular Ca ions are activated at less positive potentials than Ca currents Mg ions do not permeate the Ca channel and changes in [Mg]o produce shifts in the activation-potential curves that are comparable to the effects of changes in [Ba]o or [Sr]o Inactivation of Ba currents also occurs at less positive potentials Perfusion intracellularly with EGTA reduced inactivation of Ca currents as a function of potential, but did not shift the inactivation-potential curve Hence, Ca current-dependent inactivation which is blocked by intracellular EGTA probably does not involve a similar change of intracellular surface potential The voltage shifts of activation and inactivation produced by extracellular divalent cations used singly or in mixtures can be described by the Gouy-Chapman theory for the diffuse double layer with binding (Gilbert & Ehrenstein, 1969; McLaughlin, Szabo & Eisenman, 1971) From the surface potential values and the Boltzman distribution, we have computed surface concentrations that predict the following experimental observations: 1) saturation of current-concentration relationships when surface potential is changing maximally; 2) the increase in peak current when Ca ions are replaced by Sr or Ba ions; and 3) the greater inhibitory effect of Mg on IBa than ICa Theory indicates that surface charge cannot be screened completely even at 1 M [Mg]o and thus that Ca channel properties must be evaluated in the light of surface charge effects For example, after correction for surface charge effects the relative permeabilities of Ca, Ba and Sr ions are equivalent In the presence of Co ions, however, Ca ions are more permeable than Ba ions suggesting a channel binding site may be involved

Intracellular pH and Na fluxes in barnacle muscle with evidence for reversal of the ionic mechanism of intracellular pH regulation.

Abstract: The ion transport mechanism that regulates intracellular pH (pHi) in giant barnacle muscle fibers was studied by measuring pHi and unidirectional Na+ fluxes in internally dialyzed fibers. The overall process normally results in a net acid extrusion from the cell, presumably by a membrane transport mechanism that exchanges external Na+ and HCO-3 for internal Cl- and possibly H+. However, we found that net transport can be reversed either by lowering [HCO-3]o and pHo or by reducing [Na+]o. This reversal (acid uptake) required external Cl-, was stimulated by raising [Na+]i, and was blocked by SITS. When the transporter was operating in the net forward direction (acid extrusion), we found a unidirectional Na+ influx of approximately 60 pmol . cm-2 . s-1, which required external HCO-3 and internal Cl- and was stimulated by cyclic AMP and blocked by SITS or DIDS. These properties of the Na+ influx are all shared with the net acid extrusion process. We also found that under conditions of net forward transport, the pHi-regulating system mediated a unidirectional Na+ efflux, which was significantly smaller than the simultaneous Na+ influx. These data are consistent with a reversible transport mechanism which, even when operating in the net forward direction, mediates a small amount of reversed transport. We also found that the ouabain-sensitive Na+ efflux was sharply inhibited by acidic pHi, being totally absent at pHi values below approximately 6.8.