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Biomedical subjects

R R MacGregor

Publications and source records attributed to R R MacGregor.

At least 181 records · Page 10Linked to original sources
PubMed1978

Granulocyte function and levels of immunoglobulins and complement in patients admitted for withdrawal from alcohol.

Chronic alcoholics who had been drinking heavily until admission for withdrawal from alcohol were studied to determine their level of granulocyte function, immunoglobulin concentration, and complement system activity. Although most had some mild derangement in results of liver function tests, serum albumin concentrations were normal, and there was no clinical evidence of malnutrition or cirrhosis. Granulocyte adherence was slightly depressed in two subjects (52.4% and 54.1%; normal, 76.0% +/- 12%), although mean adherence for the group was normal. Mean chemotaxis was significantly below normal (2,103 vs. 7,943 counts per min), and the impairment was related to a defect or inhibitor in the serum of patients. Phagocytic activity was less than half that of control subjects in two alcoholics, but mean values were not depressed. Bactericidal activity was normal in all. Serum concentrations of immunoglobulins and total hemolytic complement activity were above the normal range for the group. The general inhibition of chemotaxis or the occasional defects in other granulocyte functions may contribute to the difficulty that alcoholics have with infection.

Adult↗
PubMed1978

Erythropoietin concentration in amphotericin B-induced anemia.

Amphotericin B was given to six patients with systemic fungal infections. A dose averaging 1.78 g, administered from 42 to 144 days, was associated with a fall in hematocrit to a mean value of 25.8%. Despite this degree of anemia, no elevation of erythropoietin concentrations in urine or serum could be detected. Thus, amphotericin appears to cause anemia by inhibiting erythropoietin production rather than by suppressing bone marrow activity directly.

Adult↗
PubMed1978

Comparative adherence of granulocytes to endothelial monolayers and nylon fiber.

Adherence of granulocytes to tissue culture monolayers of endothelium averaged 26.2 +/- 1.3% SEM, which was similar to their adherence on 50-mg nylon fiber columns (27.7 +/- 3.6%). In contrast, adherence to epithelial cells, fibroblasts, kidney cells, and plastic Petri dishes without monolayers was only 12.4, 9.9, 11.1, and 4.3%, respectively. Cyclic nucleotides and adherence-modifying plasma factors induced changes of adherence to endothelium similar to those in nylon fiber columns. Adherence of granulocytes in whole blood was the same as for purified granulocytes in Hank's balanced salt solution. Exposure of endothelial monolayers to 0.18% trypsin for 10 min reduced subsequent granulocyte adherence to 25.2% of control values. Incubation of trypsin-treated monolayers with nutrient medium for 4 h did not improve adherence, but values returned to normal or above by 24 h, with or without serum proteins present in the nutrient medium. The similarity of granulocyte adherence to nylon fiber and to endothelial monolayers in vitro suggests that results with the nylon fiber assay reflect in vivo granulocyte-endothelium interaction. Furthermore, the endothelial monolayer offers a new model for studying this cell-cell relationship in vitro.

Adhesiveness↗
PubMed1978

Propranolol antagonizes the anti-inflammatory effect of alcohol and improves survival of infected intoxicated rabbits.

We studied the effects of alcohol and propranolol on the course of peritonitis in rabbits. Induction of sterile peritonitis with normal saline led to a 50% augmentation of granulocyte adherence in normal rabbits, and a mean cumulative granulocyte count of 27,000/mm(3) in peritoneal exudate by 8 h. Rabbits intoxicated with alcohol at the time of peritonitis induction maintained a granulocyte adherence below pretreatment values, and only delivered a cumulative mean of 12,000 granulocytes/mm(3) into the peritoneal fluid. When intoxicated rabbits received propranolol intravenously at the time of intoxication, adherence increased above preperitonitis levels, and stayed significantly above values for animals given alcohol alone. In addition, the defect in granulocyte delivery was prevented by propranolol, resulting in a mean cumulative granulocyte count in peritoneal fluid of 24,000/mm(3).When peritonitis was induced with live pneumococci instead of a sterile inflammatory stimulus, 14/18 normal animals survived the infection and were culture-negative when sacrificed at 2 wk. In contrast, 17/18 intoxicated animals died of the infection, in a mean of 2.8 days. 9 of 18 intoxicated animals who also received propranolol survived, and those who died lived a mean of 7.5 days. The survival rates and the time-to-death among the nonsurvivors given propranolol were both significantly greater than in the animals intoxicated without propranolol. Thus, propranolol prevents the granulocyte adherence and delivery defects induced by alcohol intoxication, and significantly improves survival from infection.

Alcoholic Intoxication↗
PubMed1978

Tuberculosis: frequency of unusual radiographic findings.

The changing pattern of the radiologic presentation of tuberculosis was noted in a review of 100 consecutive cases of pulmonary tuberculosis. Active tuberculosis was not suggested as a radiologic diagnosis in 43% of the patients. Of the 100 cases, only 66 had characteristics of reactivation tuberculosis (i.e., minimal upper lobe infiltrate or more advanced cavitary disease). Of the other 34 patients, 18 had less usual presentations, making the radiographic diagnosis difficult. The remaining 16 patients had radiographic patterns quite unusual for tuberculosis, including masslike densities resembling carcinoma; chronic infiltrates in a lower lobe; miliary tuberculosis, either superimposed on diffuse interstitial lung disease or associated with a diffuse lung pattern atypical for miliary disease; and normal chest radiograph.

Adult↗
PubMed1978

Anaerobic spinal epidural abscess. Case report.

An acute spinal epidural abscess is reported from which a pure growth of the anaerobe Fusobacterium necrophorum was isolated. The mode of infection and pathogen makes it unique. The literature concerning the bacteriology of epidural abscess and the implications of anaerobic epidural infection are discussed.

Abscess↗
PubMed1978

Effect of acute alcohol intoxication on granulocyte mobilization and kinetics.

Granulocyte mobilization into skin abrasions in human volunteers was significantly inhibited by acute alcohol intoxication (45,-800 cells in 8 hr versus 353,000 in normal controls). Alcohol applied locally did not inhibit granulocyte delivery, and protection of the abrasion against heat loss did not reduce the inhibited delivery in intoxicated volunteers. Intoxication inhibited granulocyte adherence and local mobilization in parallel. Alcohol administration to rabbits shifted granulocytes from marginal to circulating pool in a manner similar to epinephrine. Mobilization of bone marrow granulocytes by glucocorticoid or endotoxin administration was not inhibited by intoxication, nor did it prevent the endotoxin-induced shift of granulocytes from circulating to marginal pool.

Alcoholic Intoxication↗
PubMed1977

A randomized clinical trial of granulocyte transfusions for infection in acute leukemia.

In a prospective, controlled, randomized study to evaluate the efficacy of filtration-leukapheresis granulocytes in granulocytopenic, febrile patients with leukemia, 19 patients received antibiotics alone, and 12 received antibiotics plus daily granulocyte transfusions from ABO-matched donors. In skin-chamber studies the granulocytes appeared at sites of inflammation for at least six hours after transfusion. Infected subjects survived longer if they received granulocytes. Differences between control and transfused patients were greatest in patients with persistent bone-marrow failure, the 21-day survival being 20 per cent in controls, and 75 per cent in transfused patients. Granulocytes appeared to have no effect on the outcome of febrile episodes in which infection was not documented, the 21-day survival being 79 per cent for controls and 88 per cent for transfused patients. The transfusion of granulocytes thus appears to offer a survival advantage to infected, persistently granulocytopenic patients.

Acute Disease↗
PubMed1977

Energy-dependent intracellular translocation of proparathormone.

We previously suggested that after synthesis, proparathormone is transferred from rough endoplasmic reticulum to the Golgi region where its conversion to parathormone occurs. We have attempted to define more closely this transfer process. In the first type of study, bovine parathyroid slices were incubated with [3H]leucine for 10 min and then radioisotope labeling was restricted by addition of a large excess of nonradioactive leucine. Under these conditions, more than 90% of the initially labeled proparathormone was converted to parathormone in 40 min. Lowered temperature in the chase period markedly inhibited the conversion. Several chemical agents were employed individually in the chase period to examine their effect on the conversion process. Antimycin A, dinitrophenol, oligomycin, and anaerobiosis (N2) inhibited the conversion, whereas sodium flouride and cycloheximide had no effect. In the second type of study, parathyroid slices were incubated with [3H]leucine for the entire incubation period. Lowered temperature and inhibitors of energy metabolism and microtubular function all lengthened the interval (lag) between the initial synthesis of [3H]parathormone. Cycloheximide, Tris, and chloroquine decreased the rates of protein synthesis and conversion, respectively, but none had any effect on the lag. We interpret the lag to represent the time of transit for proparathormone from rough endoplasmic reticulum to the Golgi region. We conclude that this transfer process is independent of the synthesis of the prohormone and its conversion to the hormone. Moreover, this translocation requires metabolic energy and appears to be mediated by microtubules.

Anaerobiosis↗
PubMed1977

Granulocyte function in patients with chronic renal failure: surface adherence, phagocytosis, and bactericidal activity in vitro.

The defects in host defense mechanisms that explain the enhanced susceptibility to infection of patients with chronic renal failure are not understood, and previous studies concerning function of polymorphonuclear leukocytes (PMNL), the major antibacterial defense, conflict. Therefore, the antimicrobial functions of PMNL obtained from chronically uremic patients and serum factors essential for PMNL activity were evaluated. The potential modifying effect of high concentrations of serum from uremic patients on PMNL of uremic patients was determined, and granulocyte adherence, an activity related to recruitment of cells to inflammatory sites, was measured. Phagocytosis of 14C-labeled Staphylococcus aureus and bactericidal activity were normal and unaffected by high concentrations of uremic serum. Serum from uremic patients opsonized staphylococci and yeast normally. Oxidative metabolism of PMNL [14C-1]glucose oxidation, O2 consumption, and quantitative protein iodination) was normal, as was PMNL adherence. If the uremic patient has an increased risk of infection, this risk cannot be ascribed to defects of PMNL responses that have been studied in these patients.

Adult↗
PubMed1977

Comparative penetration of amikacin, gentamicin, and penicillin g into exudate fluid in experimental sterile peritonitis.

Using a rabbit sterile peritonitis model, we compared the penetration of intravenously administered amikacin, gentamicin, and penicillin G into peritoneal exudate. Peritonitis was induced with sterile normal saline, and the peritoneal exudate contained 23,751 +/- 3,039 granulocytes 8 h later. Antibiotics were administered intravenously 3 h after initiating peritonitis, and serum and peritoneal fluid concentrations were measured for 5 h. Peritoneal levels of each antibiotic exceeded simultaneous serum levels by 1 h after dose and remained above serum levels thereafter. The maximum peritoneal fluid concentration of amikacin reached 71.2% +/- 12.7 of the maximum serum concentration, whereas maximum gentamicin peritoneal concentration achieved 37.1% +/- 2.7, and penicillin achieved 23.2% +/- 4.5, of their respective maximum serum concentrations.

Amikacin↗
PubMed1977

Host-defense mechanisms in hidradenitis suppurativa.

Host-defense mechanisms were studied in seven patients with active hidradenitis suppurativa (HS). Granulocyte phagocytic function was measured by ingestion of Staphylococcus aureus labeled with radioactive carbon 14 and intracellular killing was determined by bactericidal pour plate method. Chemotaxis was measured by radioactive counting of sodium chromate Cr 51 granulocytes migrating in modified Boyden chambers. Granulocyte adherence was estimated in vitro by filtering blood samples through nylon fiber columns. Cell-mediated immunity was measured by intradermal delayed hypersensitivity responses to Candida, mumps. streptokinase/streptodornase, and purified protein derivative antigens. No abnormality was demonstrated in any granulocyte or cell-mediated immune function tests. Moreover, all patients had normal immunoglobulin levels and elevated total hemolytic complement. Therefore, we conclude that HS is a localized chronic infection of apocrine glands without a generalized defect in host defense.

Adult↗
PubMed1977

Disruption of the Golgi zone and inhibition of the conversion of proparathyroid hormone to parathyroid hormone in human parathyroid tissue by tris(hydroxymethyl)aminomethane.

Tris(hydroxymethyl)aminomethane (Tris, Tromethamine, THAM) and other non-amphoteric amines were previously reported to inhibit the conversion of proparathyroid hormone to parathyroid hormone in bovine parathyroid glands incubated in vitro. This inhibition correlated with a striking dilation of the Golgi complex. This work has now been extended to normal, hyperplastic, and adenomatous parathyroid glands from human subjects. The tissues were incubated for up to 3 hours with 3H-leucine in physiologic solutions (control) or in the same solutions containing 50 mM Tris. In one case, diethylamine also was tested. Electron microscopy revealed that the amines produced a dilation of the Golgi complex and swelling of vesicles, predominantly in the region of the Golgi zone. Other organelles were normal in appearance. During the same period, Tris reduced by sixfold the ratio of the parathyroid hormone to proparathyroid hormone, from a control value of 2:1 to 1:3. It was apparent that Tris exerted the same biochemical and morphologic actions in human parathyroid tissues as it was previously shown to do in bovine glands. These studies support the concept that the Golgi zone is that region in the parathyroid gland in which proparathyroid hormone to parathyroid hormone conversion is initiated and that Tris inhibits this conversion through disruption of the converting site.

Adenoma↗
PubMed1977

Radiopharmaceuticals XXVII. 18F-labeled 2-deoxy-2-fluoro-d-glucose as a radiopharmaceutical for measuring regional myocardial glucose metabolism in vivo: tissue distribution and imaging studies in animals.

18F-2-Deoxy-2-fluoro-D-glucose (18FDG) is rapidly extracted by the mouse heart, and the radioactivity in heart (3-4% per organ) remains relatively constant for 2 hr post injection. The brain uptake (2-3% per organ) remained relatively constant throughout the time course of the study. Liver, lungs, kidneys, small intestine, and blood all showed a rapid clearance of radioactivity after injection of 18FDG. At 120 min the heart-to-lung ratio was 12 and heart-to-liver ratio was 32. Urinary excretion of activity was approximately 16% of the injected dose at 60 min. The uptake of radioactivity by dog heart following the intravenous administration of 18FDG was 2.8-4.1% at 60 min and 2.4% at 135 min; it was regionally distributed, the areas of highest activity being the left ventricle and the interventricular septum. The brain activity was 2.1-3.5% at 120 min, with a ratio of gray matter-to-white matter of 2-3:1. Urinary excretion in dogs was 16% and 50% of the injected dose at 60 and 135 min. The chemical form of the activity in the urine, although unidentified, was not 18F-. Cross-sectional images of the myocardium of the dog after intravenous injection of 18FDG were obtained using emission tomography.

Animals↗