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Biomedical subjects

R B Scott

Publications and source records attributed to R B Scott.

At least 91 records · Page 5Linked to original sources
PubMed1989

Alcohol effects in the elderly.

Alcohol is a potent drug and must be included in the medication history of the patient. The physician must be alert to the possibility of alcohol abuse by the elderly, in whom typical clues may not be present. Alcohol has a greater dose-related effect in elderly persons because of their decreased total body water, which leads to persistently higher blood alcohol levels. Alcohol causes unique kinds of brain damage, a fact that may aggravate the clinical symptoms of dementia such as Alzheimer's disease, but there is no convincing proof of premature aging because of alcohol abuse. Alcohol potentiates the sedating effects of many drugs acting on the CNS. This is especially serious in elderly patients, and they should be cautioned concerning the use of alcohol and drugs.

Aged↗
PubMed1988

Biliary motility associated with gallbladder storage and duodenal delivery of canine hepatic biliary output.

Hepatic biliary output may be stored in the gallbladder (GB) or delivered into the duodenum. The role of the GB and sphincter of Oddi (SO) in the partition of hepatic biliary output between GB and duodenum was studied in 6 dogs during the interdigestive and postprandial periods. Three animals received a continuous intravenous infusion of [14C]taurocholic acid, which served as a marker of the steady-state hepatic output of radiolabeled bile acid. Gallbladder filling and emptying and duodenal delivery of [14C]taurocholic acid were determined using duodenal marker perfusion to measure output. Sphincter of Oddi, common duct, GB, and duodenal manometry was performed in 3 additional dogs. During fasting, partial GB emptying and an increased rate of duodenal delivery occurred between 60% and 90% of each cycle of the migrating motor complex. The majority of hepatic taurocholic acid output was stored in the GB during the first half of the migrating myoelectric complex. However, in the latter half of the migrating myoelectric complex, the frequency of SO contractions and basal SO pressure decreased, GB pressure increased, net partial GB emptying occurred, and peak rates of duodenal taurocholic acid delivery were achieved. Feeding induced immediate decreases in basal SO pressure and frequency of phasic contractions, and an immediate increase of GB pressure. Gallbladder emptying and duodenal taurocholic acid delivery were maximal in the first 10 min after feeding. Thus, both the cyclic interdigestive and immediate postprandial increases in duodenal bile acid delivery are associated with SO relaxation and GB contraction. The immediate postprandial changes in SO and GB motility, and in duodenal bile acid output, suggest a cephalic phase of postprandial duodenal bile acid delivery.

Ampulla of Vater↗
PubMed1988

Metoclopramide in gastroesophageal reflux of infancy.

This study examined the effect of metoclopramide on lower esophageal sphincter (LES) pressure, and frequency and duration of reflux episodes in 28 children (mean age (+/- SD) 9 +/- 11 months) referred for evaluation of gastroesophageal reflux (GER). Esophageal manometry was performed before and after one intravenous dose of metoclopramide (0.125 mg/kg), and esophageal pH was monitored over a 24-hour baseline period, followed by oral metoclopramide therapy (0.125 mg/kg four times a day, for 24 hours.) During pH monitoring, patients received diet for age and were kept in the prone position with the head elevated 45 degrees while sleeping. Eight patients entered a 6-month double-blind, placebo-controlled trial of metoclopramide. Metoclopramide significantly (P = 0.04) increased end-expiratory LES pressure, from 14.9 +/- 7.5 mm Hg to 18.6 +/- 6.8 mm Hg. However, there was a significant (P less than 0.05) increase in the number of reflux episodes/24 hours, and no significant change in percentage of time pH was less than 4, number of episodes lasting greater than 5 minutes, or the longest episode of reflux between the 24-hour baseline and M periods. LES pressure did not correlate well with any of these measurements (r = 0.2). In the controlled trial, the three patients receiving metoclopramide, but none of those receiving placebo, were withdrawn by their parents because of exacerbation of GER symptoms and marked irritability (P = 0.01). In the placebo group, symptoms improved in four infants, but did not change in one. The use of metoclopramide in the treatment of GER of infancy needs to be reconsidered.

Double-Blind Method↗
PubMed1988

Do motilin and pancreatic polypeptide regulate duodenal bile acid delivery?

The plasma levels of the enteric hormones, motilin and pancreatic polypeptide, cycle in association with fasting intestinal motility and are altered by feeding. Intravenous administration of motilin causes gallbladder contraction and increased sphincter of Oddi phasic motor activity, whereas pancreatic polypeptide causes gallbladder relaxation. To determine if endogenous plasma levels of motilin and pancreatic polypeptide control sphincter of Oddi and gallbladder motility, and regulate duodenal bile acid delivery, we measured during fasting and after feeding the correlation between (a) changes in plasma motilin or pancreatic polypeptide, and (b) the duodenal delivery of a steady-state hepatic output of radiolabelled bile acid. Four dogs were prepared with duodenal cannulas. Duodenal motility was recorded manometrically. Plasma levels of pancreatic polypeptide and motilin were determined during a full cycle of the migrating myoelectric complex for 20 min before and 40 min after ingestion of a standard meal. To assess the effect of the sphincter of Oddi and the gallbladder together, or the gallbladder alone on duodenal bile acid delivery, the dogs received a continuous i.v. infusion of [14C]taurocholic acid (TCA); duodenal delivery of TCA was quantitated with the sphincter of Oddi intact using duodenal marker perfusion, or with the sphincter of Oddi cannulated and zero outflow resistance. In the interdigestive period with the sphincter of Oddi intact, only 0.1 (r2) of the variance of duodenal bile acid delivery can be predicted from the variance of motilin, and the correlation of plasma pancreatic polypeptide with duodenal TCA delivery is opposite that expected if pancreatic polypeptide caused gallbladder relaxation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Motility effects of intestinal anaphylaxis in the rat.

Intestinal motility was examined in an animal model of intestinal anaphylaxis. Hooded-Lister rats were sensitized (S) by intraperitoneal injection of 10 micrograms egg albumin (Ag) and compared with sham-sensitized controls (C). Seven days later three bipolar jejunal electrodes and a jejunostomy tube for motility recording and Ag administration were implanted. On day 14 intestinal myoelectric and motor activity were measured in fasted animals before and after intraluminal administration of either 10 mg egg albumin in 0.5 ml saline, 10 mg bovine serum albumin (BSA) in 0.5 ml saline, or placebo (P) challenge with 0.5 ml saline. Specific immunoglobulin E serum titers were greater than or equal to 1:64 in S animals, whereas C animals showed no response. None of the C animals challenged with P or Ag and none of the S animals challenged with P or BSA defecated after challenge, but all the S animals challenged with Ag developed diarrhea (P less than 0.001). In S animals challenged with Ag, the fasting motility pattern was disrupted, the migrating motor complex was abolished (P = 0.002), and the frequency of aborally propagating clustered contractions was increased (P less than 0.01). In this animal model an immune-mediated reaction to food protein was associated with diarrhea and altered intestinal myoelectric and motor activity.

Anaphylaxis↗
PubMed1988

Coping with sickle cell disease: a profile and perspective of a pioneer self-help group.

Sickle cell anemia is a chronic, debilitating disease that is passed genetically from generation to generation. It is a disease marked by periods of well-being and crisis, and it has a profound effect on all bodily organs, shortening the lifespan of its victims. The disease also has far-reaching effects on family functioning and relationships. Support for affected families and individuals is therefore a vital component of any management regimen.In the 1960s, the idea for the Association for Sickle Cell Anemia Research (ASCAR) was implemented. The group was spearheaded by Dr. Roland B. Scott and Dr. Angella Ferguson, both of whom were members of the Department of Pediatrics at Freedmen's Hospital (now Howard University Hospital).This group was perhaps the first of its kind, and adopted as its goals education and family support as well as fund-raising to aid in the support of research. This article provides an overview of the development of this group, its organization and activities, as well as an appraisal of its accomplishments. It also offers specific suggestions for formulating similar groups.

Adaptation, Psychological↗
PubMed1988

Lung function in sickle cell hemoglobinopathy patients compared with healthy subjects.

Previous studies of lung function tests performed on patients with sickle cell disease have shown a restrictive ventilatory defect, usually a diffusion defect, and mild hypoxia at rest. The present study was undertaken to explain the pathophysiology of these changes and to extend these studies to include functional measurements not reported previously.Lung function studies were performed at rest and during treadmill walking on 66 patients with sickle cell anemia and on 16 healthy control subjects. Patients had restrictive ventilatory defects, decreased lung compliance, and uneven ventilation-perfusion ratios. These abnormalities caused an increased alveolar-arterial oxygen tension difference that caused hypoxemia. The diffusion defects were because of the sickle cell disease.Carboxyhemoglobin levels were increased in patients with sickle cell disease. This increase may be caused by a combination of factors, including increased cigarette smoking, hemolysis, and preferential survival of red blood cells that contain carbon monoxide and which do not sickle. During treadmill walking, the patients with sickle cell disease showed a decreased work tolerance caused by impaired oxygen delivery. The anaerobic threshold is reached sooner in patients with sickle cell disease and may also account for the limitations in work capacity of these patients.

Adult↗
PubMed1987

Age and prevalence of sickle-cell trait in a large ambulatory population.

We performed hemoglobin electrophoresis in 30,400 apparently healthy black individuals in the Washington D.C. Metropolitan area, who were participating in a community based sickle-cell screening program during the period 1978-1985. The overall prevalence of sickle-cell trait was 6.7%. The frequency of sickle-cell trait in various age groups, which included young children, adults, and individuals over 65 years of age, ranged from 6.4 to 7.4%. There were no statistically significant differences in the prevalence of sickle-cell trait among the various age groups, nor did we detect a significant trend for increasing or decreasing sickle cell frequency with advancing age (P = 0.418). Thus, in this population sickle-cell trait appears to have no effect on longevity. If the various complications of sickle-cell trait reported in the literature are not fortuitous, their frequency and/or severity must be too low to affect prevalence figures.

Adolescent↗
PubMed1987

Argininosuccinic aciduria: long-term treatment with arginine.

The presentation and 2 year treatment of a patient with argininosuccinic aciduria is reported. Erythrocyte argininosuccinate lyase activity was less than 2% of normal. Long-term management included protein restriction and arginine dietary supplementation. The child experienced three episodes of hyperammonaemia (greater than 100 microns), the first at birth, the second at 6.5 months and the third at 16 months. Neurological development deteriorated between 14 and 24 months. Hepatomegaly and biochemical hepatitis, a feature of this condition, was accompanied by enlarged mitochondria with tubular paracrystalline inclusions not previously recognized in this disorder.

Amino Acid Metabolism, Inborn Errors↗
PubMed1987

Esophageal function following Livaditis repair of long gap esophageal atresia.

Proximal pouch esophagomyotomy (Livaditis) allows for repair of long gap esophageal atresia (EA). Postoperative esophageal functional studies in these patients are lacking. Six such infants were followed for up to 42 months. Esophageal function was assessed clinically and by barium swallow, manometry, 24 hr pH monitoring, esophagoscopy, and biopsy. Operative complications included two minor anastomotic leaks and two asymptomatic diverticula at the myotomy site. All patients had dysmotility on barium swallow. Gastroesophageal reflux (GER) was seen in four. Manometry showed a variable aperistaltic segment in each infant but lower esophageal sphincter pressures and relaxation were retained. Twenty-four hour pH monitoring showed an increase in frequency and duration of GER. All four patients biopsied had esophagitis. Five of the six patients showed normal growth velocity. Livaditis modified repair of EA was not associated with significant surgical complications. Esophageal motility showed abnormalities similar to those reported after the standard repair of EA. Myotomy did not adversely affect the esophageal function.

Biopsy↗
PubMed1987

Gallbladder pressure, compliance, and hysteresis during cyclic volume change.

The gallbladder has both storage and contractile properties, but is pressure-volume characteristics have not been fully described. We studied gallbladder pressure, compliance, stress relaxation, and the work performed during infusion-withdrawal of fixed volumes of bile at increments of base-line volume under halothane anesthesia in 13 dogs. Two cannulae were inserted in the gallbladder fundus: one for cyclic infusion-withdrawal of bile, and one for pressure monitoring. Following ligation of the cystic duct, the gallbladder was fully aspirated and then filled to successive predetermined base-line volumes (15, 20, 25, 30, or 35 mL). At each base-line volume, 5 mL of bile was infused and withdrawn at 2.47 mL/min. Studies were performed under basal conditions and with cholecystokinin octapeptide (CCK) infusion (10 or 30 ng.kg-1.h-1iv). Pressure was measured at base-line, after infusion, and after withdrawal. Compliance during infusion (delta V/delta P) was calculated for each cycle. Stress relaxation was defined as the difference between base-line pressure and any reduction in pressure after withdrawal. Hysteresis, the difference between work of infusion and work of withdrawal, was calculated. The results were such that base-line, end-infusion, and end-withdrawal pressures; work of infusion, work of withdrawal, and hysteresis; and stress relaxation all increased significantly with increases in the predetermined base-line volumes (p less than 0.001). Compliance decreased significantly (p less than 0.001) with increasing base-line volume. CCK at 10 ng.kg-1.h-1iv had no effect, but infusion of CCK at 30 ng.kg-1.h-1 significantly (p less than 0.05) increased pressure and work, decreased compliance, and increased stress relaxation compared with controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Migrating action potential complexes--a feature of normal jejunal myoelectric activity in the rat.

To determine if migrating action potential complexes (MAPCs) are a feature of normal motility, Hooded-Lister rats (100-150 g) were surgically prepared with three pairs of bipolar jejunal electrodes spaced 2.5 cm apart and with a jejunostomy tube for motility recording. Animals were studied conscious and unrestrained on postoperative day 14 after an 18-h fast. Intestinal myoelectric and motor activity was recorded for a 1-h interval in 24 animals that continued to fast and in 12 animals that were allowed to feed for 10 min. Fasting rats had a jejunal slow wave frequency of 32 +/- 2 contractions/min which did not differ significantly after feeding. Migrating myoelectric complexes (MMC) were clearly identified in all fasting animals and had a cycle period of 10.0 +/- 3.6 min. MAPCs were seen during phase II in 83% of MMCs and had an average distribution of 4.2 +/- 3.9/MMC. Feeding abolished the MMC and initiated a continuous irregular pattern of electrical spiking and associated contractile activity. Migrating action potential complexes were seen after feeding with a frequency of 1.8 +/- 0.4/min. It is concluded that MAPCs are a common feature of normal interdigestive phase II and also of postprandial jejunal motility in the rat. This supports the hypothesis that the MAPC is a basic propulsive motor pattern intrinsic to normal intestinal function.

Action Potentials↗
PubMed1987

Chronic pancreatitis associated with ulcerative colitis.

A twelve-year-old girl without apparent predisposing factors developed chronic pancreatitis, and 10 months later had fulminant onset of ulcerative colitis requiring a colectomy. This report strengthens the evidence for a relationship between pancreatitis and inflammatory bowel disease.

Child↗
PubMed1986

HLA-B35 is associated with red cell alloimmunization in sickle cell disease.

HLA-A, -B, -C, and DR antigens were determined in 33 patients with sickle cell disease (SCD), who had received red blood cell (RBC) transfusions. Twenty-one patients formed red cell alloantibodies after transfusions (responders) while 12 multitransfused SCD patients did not form any RBC antibodies (non-responders). We found that 67% of the SCD responder participants had HLA-B35 versus 25% of the non-responders (chi 2 = 5.3079, P = 0.0212). The frequency of B35 in non-responder SCD patients was similar to that of a normal healthy Black population consisting of 139 individuals. Calculation of the relative risk showed that sickle cell patients with B35 are six times more likely to form RBC alloantibodies after transfusion than those lacking that HLA antigen. We found no significant increase or association between any HLA-DR antigens and sickle cell disease.

Adolescent↗
PubMed1986

Differentiation-associated changes in in-vitro mRNA translation in the HL60 cell line.

In order to characterize certain aspects of gene expression during the granulocytic differentiation of the HL60 cell line, we have analysed changes in the population of mRNA available for translation in vitro. RNA extracts of DMSO-induced and control cells were translated in vitro in a wheat germ cell-free protein synthesizing system. Translation products were analysed by two-dimensional electrophoresis followed by autoradiography. Autoradiograms were analysed by a computer-assisted method utilizing a drum-scanning microdensitometer. Spots were identified by their relative positions on the films and their relative intensity was estimated. One hundred and eighty-one peptides were identified in both the DMSO-induced and untreated control HL60 cells, 31 of which showed differentiation-associated changes in synthesis in vitro. The 11 peptides which decreased in synthesis did so early in the differentiation process, whereas most of the 20 peptides which increased did so at a later time. Three peptides were shown to increase more than 8-fold by day 4 of induction. A comparison with normal granule proteins from human leukocytes suggests that at least two of these may correspond to functional granule proteins. The changes in peptide patterns which we describe demonstrates that the program of gene expression during HL60 differentiation includes changes in the relative abundance of specific mRNA transcripts. The data described here also provides a standard for comparison of other proteins, such as oncogene products, as they are identified.

Blood Proteins↗