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Biomedical subjects

T L Perry

Publications and source records attributed to T L Perry.

At least 19 recordsLinked to original sources

Partial protective effect of MK-801 on MPTP-induced reduction of striatal dopamine in mice.

The protective effect of MK-801, an N-methyl-D-aspartate (NMDA) receptor antagonist on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced reduction of striatal dopamine (DA) was examined in C57 BL/6 mice. Striatal DA levels were significantly higher in animals receiving parenteral MK-801 before and for 48 h following MPTP administration after 28 days than in animals receiving MPTP alone. The effect was not due to inhibition of monoamine oxidase-B (MAO-B) by MK-801. These data suggest that NMDA receptors may be involved in some of the neurotoxicity produced by MPTP.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine

Amyotrophic lateral sclerosis: interleukin-6 levels in cerebrospinal fluid.

Recent observations indicate that antibodies to gangliosides are found in many patients with amyotrophic lateral sclerosis (ALS). If antigen-antibody complexes occur in ALS, elevations of cytokine levels might be expected, among them the cytokine interleukin-6 (IL-6). IL-6 is secreted by activated monocytes and other cell types and is an important mediator of the inflammatory response. We have measured cerebrospinal fluid (CSF) IL-6 levels in patients with ALS and compared them with those in psychiatric and neurodegenerative disorders not believed to be due to immune disorders of the central nervous system. We found no significant differences in CSF IL-6 levels between these groups.

Amyotrophic Lateral Sclerosis

Excitatory amino acid receptor antagonist in murine motoneuron disease (the wobbler mouse).

Recent evidence has suggested a potential role for involvement of excitatory amino acids (EAA) in the pathogenesis of the neuron loss in motoneuron diseases. We have examined the ability of an antagonist of N-methyl-D-aspartate (NMDA) receptors to halt or retard the progression of neurological symptoms in a murine form of motoneuron disease. The wobbler mouse is an autosomal recessive mutant which develops progressive neurological symptoms secondary to motoneuron loss. Treatment of wobbler mice with the NMDA receptor antagonist (+)-5-methyl-10,11-dihydro-5H-dibenzo(a,d)cyclohepten-5, 10-imine maleate (MK-801) did not retard neurological deterioration as assessed by a semiquantitative clinical scale. We conclude that NMDA receptor activation is probably not involved in the pathogenesis of motoneuron loss in the wobbler mouse.

Amyotrophic Lateral Sclerosis

The wobbler mouse: amino acid contents in brain and spinal cord.

Reductions in glutamate and aspartate contents, together with increased contents of taurine, have been observed in the autopsied brains and spinal cords of patients who have died with amyotrophic lateral sclerosis (ALS). The wobbler mouse develops an inherited degeneration of motoneurons within the brainstem and spinal cord, and has been proposed as an animal model of ALS. In symptomatic wobbler mice we found brain contents of glutamate, aspartate, and taurine similar to those in unaffected littermates, while brain contents of glutamine were increased, and those of serine and alanine were decreased. Spinal cords of wobbler mice had slightly decreased contents of glutamate, aspartate and glycine compared to normal littermates. Abnormalities of amino acid contents in the nervous system of wobbler mice are dissimilar to those in ALS patients suggesting a different pathogenesis of motoneuron loss.

Amino Acids

Puppet-like syndrome of Angelman: a pathologic and neurochemical study.

We present the first pathologic descriptions of the puppet-like syndrome of Angelman based on autopsy studies of a 21-year-old woman. The noteworthy findings were a small brain with mild cerebral atrophy but normal gyral development. There was marked cerebellar atrophy with loss of Purkinje and granule cells and extensive Bergmann's gliosis. Study of dendrite morphology using Golgi impregnations of the visual cortex revealed a prominent decrease in dendritic arborization of layer 3 and layer 5 pyramidal neurons. Quantitative Golgi analysis also revealed a significant decrease in the numbers of dendritic spines in apical layer 3 dendrites and both apical and basal layer 5 dendrites. Neurochemical studies of frozen brain tissue demonstrated markedly reduced gamma-aminobutyric acid content in the cerebellar cortex, as well as elevated glutamate content in the frontal and occipital cortices. Although there are no definite morphologic correlates of many of the clinical signs, the pronounced dendritic pathology and neurochemical abnormalities in cerebral cortex may provide a physiologic basis for mental retardation.

Adult

Amyotrophic lateral sclerosis: fasting plasma levels of cysteine and inorganic sulfate are normal, as are brain contents of cysteine.

Recent reports suggest that amyotrophic lateral sclerosis (ALS) is caused by one or more unidentified neurotoxins that are poorly metabolized in patients to less toxic and more readily excreted compounds, and that a genetically determined defect in cysteine degradation and in inorganic sulfate production is the mechanism underlying a failure to metabolize xenobiotics normally in ALS. We measured concentrations of total cysteine and of inorganic sulfate in the plasma of age-matched groups of ALS patients and healthy control subjects and found no differences. L-Cysteine, a putative endogenous neurotoxin in ALS, was present in equal concentrations in autopsied brain from ALS patients and controls.

Adult

What excitotoxin kills striatal neurons in Huntington's disease? Clues from neurochemical studies.

Amino acid analyses of both caudate nucleus and putamen obtained at autopsy from patients dying with Huntington's disease (HD), and from control subjects, showed significantly decreased mean glutamate contents in the HD patients. In addition, the mean glutamate concentration was significantly increased in the CSF of living HD patients as compared with controls. Neurochemical studies also showed that neither aspartic acid, proline, 5-oxoproline, nor homocysteic acid is likely to act as a causative excitotoxin in HD. Excessive striatal glycine content, or deficient glutathione content, is unlikely to contribute to the effects of a causative excitotoxin in HD. We suggest that glutamic acid may be the proximate causative neurotoxin in the striatum in HD, as a result of an unexplained failure in the reuptake mechanism for glutamate released there as an excitatory neurotransmitter.

Adult

Gamma-aminobutyric-acid deficiency in brain of schizophrenic patients.

Gamma-aminobutyric acid (G.A.B.A.) was measured in the nucleus accumbens and thalamus of brains from patients who had died with schizophrenia or Huntington's chorea (H.C.) and from control subjects. Mean G.A.B.A. content was significantly reduced in both brain areas in schizophrenia and in H.C. Extraneous factors, such as age, interval from death to necropsy, cause of death, and drug use, did not readily explain the observed reduction in brain G.A.B.A. G.A.B.A. deficiency may be a biochemical characteristic of some forms of schizophrenia.

Brain Chemistry

Familial fatal Parkinsonism with alveolar hypoventilation and mental depression.

The clinical, pathological, and neurochemical characteristics of a newly recognized inherited neurological disorder are reported. Lethargy and mental depression are early symptoms, followed by mild parkinsonism and progressive weight loss. Failure of automatic respiratory control develops and may result in sudden death. Advanced degeneration of the substantia nigra, cell loss and gliosis of the basal ganglia, and focal gliosis in the medulla are seen on pathological study. Degeneration of the nigrostriatal dopaminergic system is evidenced by low levels of tyrosine hydroxylase, dopamine, homovanillic acid, and L-dopa decarboxylase in postmortem brain samples. Taurine concentrations in fasting plasma and CSF are somewhat depressed; brain contents of taurine are within normal limits.

Brain

Isoniazid therapy of Huntington disease.

We describe clinical and biochemical changes in seven patients with Huntington disease given isoniazid (INH) in dosages three to five greater than normally used in tuberculosis. Because INH inhibits the enzyme gamma-aminobutyric acid aminotransferase (GABA-T), and increases GABA content in the brains of experimental animals, it might correct the brain GABA deficiency characteristic of Huntington disease. Of six patients treated long enough to be clinically evaluated, one showed marked and two others showed signifciant improvement. High-dose INH therapy carries serious toxic risks, which are influenced by patients' acetylator phenotypes. Nevertheless, results are sufficiently promising to warrant further controlled trials of INH or other GABA-T inhibitors in Huntington disease.

4-Aminobutyrate Transaminase