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Biomedical subjects

J A Thompson

Publications and source records attributed to J A Thompson.

At least 325 records · Page 18Linked to original sources
PubMed1977

Evaluation of central nervous system vaccinia antibody synthesis in multiple sclerosis patients.

A serum/cerebrospinal fluid (CSF) ratio method was used to determine whether elevated CSF vaccinia antibody titers in some patients with multiple sclerosis are the result of central nervous system antibody synthesis or of a leak in the blood-brain barrier. Nine of 20 multiple sclerosis patients were noted to have a depressed serum/CSF vaccinia antibody ratio and a normal ratio for poliovirus-I, an agent thought not to be involved in the pathogenesis of multiple sclerosis. These data suggest central nervous system synthesis of vaccinia neutralizing antibody. Vaccinia virus antigens may play an important direct or indirect role in the pathogenesis of multiple sclerosis.

Adult↗
PubMed1977

Mitochondrial and microsomal phospholipids of Morris hepatoma 7777.

The phospholipids of both mitochondrial and microsomal membranes from normal liver, host liver, and Morris hepatoma 7777 were isolated, separated, and quantitated. The total as well as the individual fatty acid concentrations and compositions were determined. The total phosphlipids isolated from tumor mitochondria were idly altered, compared with mitochondria from other normal or host liver. The polyenoic acids were decreased, and there was a concomitant increase in the monoenes. When the respiratory control was determined, the tumor mitochondria exhibited a significant decrease in this parameter. The tumor microsomal membrane fraction, on the other hand, contained about 50% less phospholipid than the controls. The fatty acid patterns of the total as well as the individual phospholipids were quite similar to those observed in the mitochondria. The species of phosphatidylcholine from both membrane fractions were separated by argentation chromatography of the intact molecules, and, as predicted by the fatty acid compositions, the major species of the tumor was the monoenoic/dienoic fraction. The acyl coenzyme A:1-acyl glycerophosphorylcholine acyltransferases, which aid in controlling the fatty acid composition of phospholipids, were measured. The very marked increase in activity of these enzymes toward polyenoic as well as monoenic fatty acids suggested that the polyenoic acids were not available for use in the resynthesis of the phosphatidylcholines in the tumor.

1-Acylglycerophosphocholine O-Acyltransferase↗
PubMed1977

Urinary organic acids quantitated by age groups in a healthy pediatric population.

Urine samples from 92 individuals of a healthy pediatric population ranging in age from less than 24 h to 12 years were analyzed for organic acid content (amino acids excepted). A few samples from adults were included for purposes of comparison. Acids were extracted by using an anion-exchange procedure, converted to trimethylsilyloxime derivatives, and analyzed by gas chromatography with the help of a small computer system. Identifications were confirmed by using a combined gas chromatograph/mass spectrometer/computer system. The data has been tabulated according to five pediatric age groups. Despite large individual variation within age groups, significant differences in amounts of several acids excreted (based on urinary creatinine concentration) have been determined between age groups. Such differences might be due to one or a combination of several factors, including changes with age in creatinine excretion, in physiologic maturity, and in diet. Such data may help to provide a basis for diagnosing metabolic abnormalities in pediatric patients.

Adult↗
PubMed1976

Salicylate poisoning complicated by fluid retention.

We have presented two cases of salicylate poisoning that demonstrate fluid retention in the face of adequate hydration, resembling the syndrome of inappropriate secretion of ADH. These cases necessitated marked alterations from normal fluid therapy. Mannitol was found to be an effective, albeit transient, diuretic for treating the acute symptoms associated with fluid retention, but only strict fluid restriction resulted in a prompt and satisfactory diuresis.

Adult↗
PubMed1976

The effects of morphine- and nalorphine- like drugs in the nondependent and morphine-dependent chronic spinal dog.

Three different syndromes produced by congeners of morphine have been identified in the nondependent chronic spinal dog. These syndromes have been attributed to interaction of agonists with three distinguishable receptors (mu, kappa and sigma). Morphine is the prototype agonist for the mu receptor, ketocyclazocine for the kappa receptor and SKF-10,047 for the sigma receptor. The morphine syndrome (mu) in the dog is characterized by miosis, bradycardia, hypothermia, a general depression of the nociceptive responses and indifference to environmental stimuli. Ketocyclazocine (kappa) constricts pupils, depresses the flexor reflex and produces sedation but does not markedly alter pulse rate or the skin twitch reflex. SKF-10,047 (sigma), in contrast to morphine and ketocyclazocine, causes mydriasis, tachypnea, tachycardia and mania. The effects of these three drugs can be antagonized by the pure antagonist naltrexone, indicating that they are agonists. Further, chronic administration of morphine, ketocyclazocine and SKF-10,047 induces tolerance to their agonistic effects. Morphine suppresses abstinence in morphine-dependent dogs while ketocyclazocine does not. Ketocyclazocine at best precipitated only a liminal abstinence syndrome in the morphine-dependent dog, indicating that it had little affinity for the morphine receptor. Ketocyclazocine thus appears to be a selective agonist at the kappa receptor. Further, it has been shown that buprenorphine is a partial agonist of the mu type which both suppressed and precipitated abstinence in the morphine-dependent dog while morphine and propoxyphene are stronger agonists. Apomorphine and SKF-10,047 produce similar pharmacologic effects suggesting that sigma activity may involve a dopaminergic mechanism.

Animals↗
PubMed1975

Studies on the mechanism of the NADPH-catalyzed peroxidation of endogenous microsomal lipid.

The importance of metal chelation in the mechanism of microsomal lipid peroxidation has been studied using both phosphate- and sulfhydryl-containing compounds. The optimal concentration for maximum stimulation by each of these compounds has been determined, and the decrease in stimulation observe at concentrations above the maxima has been related to the ability of these compounds to form stable chelation complexes with non-heme iron. Of the compounds tested, only ADP and ATP facilitated the cooperative binding of NADPH to the membrane and thus suggested the possibility of three binding sites for NADPH. Neither of the other two phosphate-chelating agents (Pi or PPi) and neither of the two thiols (cysteine or dithiothreitol)facilitated cooperative binding of NADPH. These data suggested that the adenine ring of ADP or ATP is directly involved in the cooperativity of NADPH binding. They also emphasized that the binding of the chelation complex to the protein is an important parameter in the mechanism of the NADPH-catalyzed peroxidation of endogenous microsomal lipids. Furthermore, stimulation of the rat of lipid peroxidation by sulhydryl-containing compounds, by freezing thawing the microsomal protein, and by treatment of the protein with detergent may be due to a decrease in this cooperative binding effect. Since cysteine and deoxycholate as well as freezing and thawing alter membrane structure, the stimulation of lipid peroxidation seems to involve some alteration to the structure of the microsomal membrane prior to the onset of enzymatic lipid peroxidation.

Adenosine Diphosphate↗