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Biomedical subjects

S Morrison

Publications and source records attributed to S Morrison.

At least 37 records · Page 2Linked to original sources
PubMed1989

Enlarged gastric folds in association with Campylobacter pylori gastritis.

Enlarged gastric folds in pediatric patients are uncommon. Fifteen patients with upper gastrointestinal (GI) tract symptoms of chronic epigastric abdominal pain, vomiting, or hematemesis underwent radiologic upper GI barium studies and were found to have Campylobacter pylori gastritis at endoscopic biopsy. Seven patients (47%) with C pylori gastric disease had radiologic evidence of enlarged folds. There was no clinical or pathologic evidence of Ménétrier disease. Therefore, C pylori gastritis should be considered in the differential diagnosis of children with upper GI tract symptoms and radiologic evidence of enlarged folds.

Adolescent↗
PubMed1989

Cholinergic regulation of arterial pressure by the C1 area of the rostral ventrolateral medulla.

In anesthetized, paralyzed rats intravenous administration of the acetylcholinesterase inhibitor physostigmine (PHY) (100 micrograms/kg) evoked a dose-related rise in arterial pressure (AP) and heart rate (HR) and an associated increase in sympathetic nerve activity (SNA). The responses to PHY were blocked by electrolytic lesions of, or microinjection of kainic acid into, a specific site in the rostral ventrolateral medulla containing a cluster of neurons immunoreactive for the adrenaline-synthesizing enzyme phenylethanolamine N-methyltransferase and corresponding to the C1 area of the nucleus reticularis rostroventrolateralis (RVL). The C1 area and its surround contain a heretofore unrecognized network of varicose neuronal processes and perikarya labeled immunocytochemically with a monoclonal antibody to the ACh-synthesizing enzyme, choline acetyltransferase (CAT). PHY increased, by over 3-fold, the spontaneous activity of reticulospinal cardiovascular neurons in the C1 area which excite preganglionic sympathetic neurons in the intermediolateral spinal column. The effects of PHY on AP, SNA, and the discharge of reticulospinal neurons were blocked by systemic administration of the muscarinic antagonist scopolamine. Microinjections within the C1 area of the RVL of scopolamine, the M2-selective muscarinic receptor antagonist AF-DX 116, or the high-affinity choline uptake inhibitor hemicholinium-3 blocked the pressor effects of PHY. The nicotinic antagonist hexamethonium and the M1-selective muscarinic receptor antagonist pirenzepine were without effect. We conclude that (1) the increases in AP, HR, and SNA elicited by the systemic administration of PHY result from the augmented action of ACh released from cholinergic terminals within the C1 area of the RVL; (2) the locally released ACh acts through muscarinic receptors of the M2 subtype within the C1 area to produce excitation of intrinsic reticulospinal sympathoexcitatory neurons, thereby increasing the activity of sympathetic preganglionic neurons and consequently elevating AP and HR; and (3) while the specific function of the cholinergic innervation of the C1 area in cardiovascular regulation is unknown, it may contribute to the tonic regulation of AP.

Animals↗
PubMed1988

New differentiation antigens associated with the growth and maturation of B lymphocytes.

Monoclonal antibodies (mAb) NDA3 and NDA4 were generated by hyperimmunizing mice with an alloreactive human T cell clone and fusing the splenocytes with the NS1 myeloma. Immunofluorescence studies indicated that these mAb react with activated, but not with resting T and B lymphocytes or with other types of cells. Immunoprecipitation studies with 125-I-labeled extracts from T and B cell lines demonstrated that the m.w. of the antigen recognized by mAb NDA3 is 36,000 and that of NDA4 is 46,000. Studies on the effect of mAb NDA3 and NDA4 on Epstein Barr Virus-transformed lymphoblastoid B cell lines (LBCL) demonstrated that these antibodies stimulate B cell proliferation and Ig synthesis. The level of expression of NDA3 and NDA4 on the membrane of LBCL is significantly augmented when cells are grown in the presence of recombinant human interferon-beta and gamma and is decreased in the presence of 12-O-tetradecanoyl-phorbol-13-acetate. These observations, in conjunction with the stimulatory effect of mAb NDA3 and NDA4 on the growth and differentiation of LBCL, suggest that these new differentiation antigens, NDA3 and NDA4, may serve as growth factor receptors.

Animals↗
PubMed1988

Biochemical changes associated with thermal biofeedback treatment of hypertension.

Fifty-two hypertensive patients whose blood pressure (BP) was controlled on two medications received either 16 sessions of thermal biofeedback (n = 30) for hand warming or 8 sessions of progressive muscle relaxation (n = 22) prior to medication withdrawal. A number of biochemical measures, including plasma norepinephrine (NEPI) (supine and standing), plasma renin activity, plasma aldosterone, and urinary sodium and potassium, were taken before treatment and after treatment while medication remained constant. Results for the biofeedback-treated patients showed significant reductions in mean arterial pressure as well as in both supine and standing NEPI, while the other biochemical measures were unchanged. There were no significant changes on any variable for the relaxation-treated patients. Although the group data support a reduction in peripheral sympathetic tone as associated with the decrease in BP for the thermal biofeedback condition, dose-response relations were not significant.

Adult↗
PubMed1988

Unsuspected adrenal masses in the neonate: adrenal cortical carcinoma and neuroblastoma. A report of two cases.

Masses involving the adrenal in the neonate are most commonly due to hemorrhage. The literature involving the neonatal adrenal reflects this propensity. Although there have been reports of newborns with neuroblastoma [1, 2] and other tumors [3], which are more common in older children, ultrasonographic descriptions of masses involving the adrenal secondary to such tumors are rare [1]. Within a 6-month span we have discovered a clinically unsuspected adrenal carcinoma and adrenal neuroblastoma.

Adrenal Cortex Neoplasms↗
PubMed1988

Cats see subjective contours.

Behavioural techniques were used to determine whether cats are able to see subjective contours. Through several stages of testing with increasingly complex displays, cats continued to respond to a figure defined by subjective contours. This result provides the first direct evidence that a nonhuman perceives subjective contours.

Animals↗
PubMed1988

The C1 area of the brainstem in tonic and reflex control of blood pressure. State of the art lecture.

Recent studies have demonstrated that the neurons of the lower brainstem that are responsible for maintaining normal levels of arterial pressure reside in a specific area of the rostral ventrolateral medulla. In rat, the critical zone corresponds to a small region containing a subpopulation of the adrenergic C1 group, defined immunocytochemically by the presence of the epinephrine-synthesizing enzyme phenylethanolamine N-methyltransferase. Neurons of this region (the C1 area), possibly including the adrenergic neurons, directly innervate preganglionic neurons in the spinal cord, and are tonically active and sympathoexcitatory. The excitatory transmitter released into the spinal cord is unknown. The discharge of C1 area neurons is locked to the cardiac cycle and, in turn, leads to firing of sympathetic preganglionic neurons. The C1 area neurons are inhibited by baroceptor input and mediate the vascular component of baroceptor reflexes. They also mediate somato-sympathetic pressor responses from skin and muscle and participate in reflex responses to hypoxia. The neurons are directly innervated by local neurons containing gamma-aminobutyric acid, acetylcholine, enkephalin, and substance P, all of which modulate arterial pressure. The C1 area is the site of the hypotensive actions of clonidine. Clonidine appears to act on imidazole receptors in the C1 area to lower arterial pressure. The natural ligand for these receptors may be a newly defined substance in brain, clonidine-displacing substance. Neurons of the C1 area appear to be the critical neuronal group governing the normal resting and reflex control of arterial pressure. They may play a critical role in the maintenance of elevated arterial pressure in hypertension and as a site of action of antihypertensive drugs.

Animals↗
PubMed1988

Stimulation of opiate receptors in the dorsal pontine tegmentum inhibits reflex contraction of the urinary bladder.

In urethane-anesthetized rats the i.v. administration of the potent short-acting opioid, fentanyl, elicited inhibition of rhythmic spontaneous reflex increases in vesical pressure (VP) evoked by urinary bladder distension. The duration of fentanyl-induced inhibition was dose-related between 0.8 and 8.0 micrograms/kg i.v. Pretreatment with the opiate receptor antagonist, naloxone HCl (250 micrograms/kg i.v.), antagonized completely fentanyl's effect on VP rhythm. Results similar to those obtained with fentanyl were observed after the bilateral stimulation of opiate receptors in the dorsolateral tegmental-subceruleus region of the pons (DLT-SC region) with D-Ala2-Met5-enkephalinamide (DAMA) microinjections. These inhibitory effects were dose-related and significant between 1.0 and 100.0 ng/site. DAMA in the DLT-SC did not alter basal cardiorespiratory parameters. The systemic and local administration of naloxone reversed rapidly the VP effects elicited by DAMA in the DLT-SC region. Naloxone alone, administered either i.v. or locally in the DLT-SC region, increased the frequency of spontaneous reflex increases in VP. Moreover, pretreatment of the DLT-SC region with naloxone microinjections significantly (55% reduction) decreased the duration of fentanyl (8.0 micrograms/kg i.v.)-induced inhibition of VP rhythm. Neurons in DLT-SC region whose discharge increased just before and throughout spontaneous increases in VP (vesical contraction-related units), were inhibited rapidly and completely by the systemic administration of fentanyl. However, fentanyl elicited a prolonged decremental discharge in neurons of the DLT-SC region with discharge patterns related to vesical relaxation (vesical relaxation-related units).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Arteriopathy in children with acquired immune deficiency syndrome.

Pathologic features of the arteries of different organs (heart, lungs, kidneys, spleen, intestine, brain) seen at autopsy in 6 children with acquired immune deficiency syndrome (AIDS) are described. Small and medium-sized arteries, which were the most commonly involved, showed intimal fibrosis with fragmentation of elastic tissue, fibrosis and calcification of media with variable luminal narrowing, and a vasculitis or perivasculitis that was seen only in the brain in association with AIDS encephalopathy. In 1 case aneurysms of the right coronary artery with thrombosis and myocardial infarction were seen. Vascular inflammation, seen only in the brain, may be related to the agent associated with AIDS encephalopathy. The fibrocalcific arterial lesions most closely resemble idiopathic arterial calcification of infancy, but because of differences in age incidence, clinicopathologic and immunologic features, and the size and distribution of the involved arteries, the arterial lesions of pediatric AIDS appear to constitute a distinctive arteriopathy. Infection, secondary to immunodeficiency and resulting in increased exposure to endogenous and exogenous elastases, may be the pathogenesis. Luminal narrowing caused by arterial lesions may play a contributory role in the pathogenesis of the atrophy, cell depletion, scarring, and necrosis or infarction found in organs of children with AIDS. Pediatricians should be alerted to the possibility of arterial involvement in pediatrics AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Pediatric AIDS.

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Acquired Immunodeficiency Syndrome↗
PubMed1986

The ideal chart.

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Documentation↗
PubMed1984

Azygos continuation of the inferior vena cava: demonstration by NMR imaging.

Azygos continuation of the inferior vena cava was diagnosed by magnetic resonance (MR) imaging in a patient with a right tracheobronchial angle mass. The characteristic findings included a dilated azygos vein and absence of the hepatic segment of the inferior vena cava. Advantages of MR imaging in evaluation of anomalies of the cava are discussed.

Adult↗
PubMed1984

Isolation and analysis of aroFo mutants by using an aroF-lac operon fusion.

The lac structural genes were fused to the regulatory region of the aroF-tyrA operon so that the expression of beta-galactosidase was regulated by the tyrR+ gene product. Transducing phage carrying the aroF-lac fusion were isolated, and a lambda aroF-lac lysogen was used to select for aroFo mutants. A plasmid vector was constructed onto which the aroFo mutations were transferred by recombination in vivo.

Coliphages↗
PubMed1983

Attitudes, beliefs and alcohol use. An analysis of relationships.

The relationships between attitudes toward alcohol and actual drinking behavior were examined. Attitudes toward specific drinking behaviors correlated better with those behaviors than did more global attitudes. Heavy drinkers believed that drinking heavily resulted in positive experiences.

Adolescent↗