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Biomedical subjects

T L Perry

Publications and source records attributed to T L Perry.

At least 127 records · Page 7Linked to original sources
PubMed1976

Cerebrospinal fluid and plasma glutamine elevation by anticonvulsant drugs: a potential diagnostic and therapeutic trap.

Administration of phenobarbitone or primidone can produce an elevation of glutamine and ornithine concentrations, together with a reduction of urea concentrations, in the fasting plasma and CSF of some infants, and in the CSF of some older epileptic patients. These two anticonvulsant drugs may interfere with the metabolic conversion of ammonia to urea, possibly by enzyme inhibition at the step of carbomoyl phosphate synthesis. The elevation of glutamine in plasma and CSF can mimic values found in some hyperammonemias. Recognition of this drug reaction can prevent erroneous diagnoses of genetically-determined urea cycle disorders and subsequent inappropriate therapy.

Adolescent↗
PubMed1976

Lactic acidosis in three sibs due to defects in both pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase complexes.

A Canadian Indian family is described in which three of the children were mentally retarded, and had seizures and other neurological abnormalities. They had chronic metabolic acidosis associated with elevated blood levels of lactate, pyruvate, and alanine. Two of the children excreted large amounts of pyruvic and alpha-ketoglutaric acids in the urine and had elevated plasma levels of glutamic acid and proline. Hypoglycemia occurred with fasting in two of the children. Treatment with pharmacological doses of thiamine, lipoic acid, biotin, riboflavin, and various dietary regimes was without effect. One child died at 3 1/2 months and another at 4 1/2 months; the third is still alive at 23 months of age. Enzyme assays revealed a low level of activity of both the pyruvate and alpha-ketoglutarate dehydrogenase complexes in cultured fibroblasts of one of the sibs. These patients appeared to have partial defects in the oxidation of pyruvate, as well as of alpha-ketoglutarate within the tricarboxylic acid cycle.

Acidosis↗
PubMed1975

Antibiotic abuse: the testimony of medical students.

Surveys of the use of antimicrobial drugs on students during antimicrobial drugs on students during their first 15 months in medical or dental school indicate that they have been treated with these agents at least three times as frequently as seems reasonable, and that the tetracyclines, ampicillin, penicillin G and erythromycin are the chief drugs overused. Antimicrobiol therapy is frequently instituted for probable viral respiratory tract infections and without any attempt to establish a bacteriologic diagnosis. It is likely that anitmicrobiol agents are used more widely in treating the general public in Canada than in treating medical students. Improvements in the rational use of this important group of drugs could increase the quality and probably reduced the cost of medical care.

Ampicillin↗
PubMed1975

Nonketotic hyperglycinemia. Glycine accumulation due to absence of glycerine cleavage in brain.

Glycine concentrations were measured in plasma and cerebrospinal fluid of five patients in different types of hyperglycinemia to determine why severe neurologic deterioration is confined to the so-called nonketotic form of hyperglycinemia. Glycine content and glycine-cleavage enzyme activity were also determined in brain obtained in autopsy from three of these patients. Spinal-fluid glycine concentrations were 15 to 30 times above normal in patients with nonketotic hyperglycinemia, but were normal in those with hyperglycinemias of undetermined type who had comparable elevations of plasma glycine. Glycine content was two to four times above normal in several brain regions, and brain glycine cleavage enzyme activity was absent in two patients dying of nonketotic hyperglycinemia. By contrast, glycine content was normal and glycine cleavage activity present in the brain of an infant who died of hyperglycinemia of unknown cause. These results suggest that elevated glycine levels may be harmless in blood, but lethal in brain.

Adult↗
PubMed1975

Hereditary mental depression and Parkinsonism with taurine deficiency.

An unusual neuropsychiatric disorder inherited in autosomal dominant fashion occurred in three successive generations of a family. Symptoms commenced late in the fifth decade in six affected patients and led to death in four to six years. The earliest and most prominent symptom was mental depression not responsive to antidepressant drugs or electroconvulsive therapy. This was accompanied by exhaustion, sleep disturbances, and marked weight loss. Later in the disease, symptoms of parkinsonism appeared, and respiratory failure occured terminally. The most recently affected family member was investigated biochemically late in his illness. Concentrations of taurine were greatly diminished in plasma and cerebrospinal fluid, and at autopsy, all regions of brain examined had a markedly reduced taurine content. Since taurine is a putative inhibitory synaptic transmitter, deficiency of brain taurine may possibly have caused the psychiatric and neurological manifestations of this disorder.

Age Factors↗
PubMed1975

Amino acids in human epileptogenic foci.

Free amino compounds were measured in 16 rapidly frozen epileptogenic foci excised from temporal or frontal cortex of nine patients with focal epilepsy, and in single cortical biopsy specimens obtained from 16 nonepileptic patients. Unlike the findings of a previous study, glutamic and aspartic acids were not diminished in the foci, nor was there a decrease in gamma-aminobutyric acid (GABA) or taurine levels. Glycine content was markedly elevated in two of 16 epileptogenic foci. These results do not suggest that deficiencies of GABA or of taurine, amino acids that may act physiologically as inhibitory neurotransmitters or modulators of inhibition, are causes of focal epilepsy, nor do they provide a logical basis for clinical trials of taurine in treatment of human epilepsy.

Adolescent↗
PubMed1975

Metabolic studies of a family with massive formiminoglutamic aciduria.

We have described two siblings who excrete massive amounts (up to 3.89 mmol/24 hr) of N-formiminoglutamic acid (FIGLU) in their urine. This unusual compound was isolated from urine, purified, and firmly identified as FIGLU by combined gas chromatography-mass spectrometry. The patients presumably have a deficiency in activity of the hepatic enzyme, glutamate formiminotransferase, which carries out the fourth sequential step in the main pathway of histidine degradation. Unlike children reported previously with this disorder, our patients had normal serum folate levels, had no hematologic abnormalities, and were not mentally retarded. Very small amounts of FIGLU were present in the plasma of one of the patients, but FIGLU was not detectable in the cerebrospinal fluid of either patient. Administration of pharmacologic doses of folic or folinic acid produced a decrease in excretion of FIGLU in urine. Histidine loading caused a small and comparable urinary excretion of FIGLU in the children's parents and in control adult subjects.

Amino Acid Metabolism, Inborn Errors↗