Eiko Itoga

Discrete regional distributions of thyrotropin releasing hormone (TRH) receptor binding in monkey central nervous system

Thyrotropin releasing hormone (TRH) directly influences central nervous system (CNS) function, independent of its pituitary action. Although these CNS effects have been behaviorally characterized, information is not yet available on the precise regional distribution of its receptor. TRH receptor binding was examined in the monkey CNS by the radioreceptor assay for clarifying the site of TRH action. TRH was bound to brain tissue membranes via high-affinity (Kd = 5.9 x 10(-9) M) and low-affinity (Kd = 11.2 x 10(-8) M) components. TRH receptor binding varied dramatically throughout the monkey brain, with more than 40-fold variation. The limbic system contained the greatest amount of binding. The next highest areas were the cerebral cortex, hypothalamus, interpeduncular nucleus and periaqueductal gray matter of the midbrain. Receptor binding was very low or not detectable in the medial thalamus, cerebellum, brain stem, spinal cord and white matter. These data suggest that TRH has an effect on the CNS via limbic system, cerebral cortex and midbrain.

Studies on familial amyloid polyneuropathy in Ogawa Village, Japan.

A newly discovered large concentration of familial amyloid polyneuropathy (FAP) in Japan is clinically outlined. The importance of the urinary secretion of IgA in these cases is stressed. Dimethyl sulfoxide administration to these patients induced clinical improvements accompanied by increased excretion of low molecular weight proteins. Amino acid composition of amyloid protein of the Ogawa village-type FAP cases was similar to that of primary amyloidosis.

STUDIES ON BIOLOGICAL ACTIONS OF DIMETHYL SULFOXIDE IN FAMILIAL AMYLOIDOSIS

DMSO was therapeutically administered to patients with FAP and in about half of the patients there was some clinical improvement. Urinary proteins were analyzed biochemically and immunochemically before and after DMSO administration in seven cases of amyloidosis. As the results, increased excretion of various proteins of different molecular weights in the urine was observed depending on cases and examined organs. The in vitro effects of DMSO on amyloid proteins were examined. DMSO-degraded amyloid proteins showed void-volume materials and lower molecular weight components on Sephadex G column elution profiles as did guanidine-degraded amyloid protein. Among various denaturating or reducing agents, DMSO is the least potent in dissolving amyloid fibrils into prealbumin-related proteins.

Immunohistochemical localization of neurotensin and β-endorphin in the rat anterior pituitary gland

Nakanes enzyme-labeled antibody technique revealed that cells containing neurotensin-like immunoreactivity were widely distributed in the anterior lobe of the pituitary body. Immunohistochemical studies on serial sections showed that a part of neurotensin positive anterior lobe cells contained beta-endorphin-like peptide simultaneously. The results show that beta-endorphin and neurotensin occur together in certain pituitary cells and this is an evidence of coexistence of more than one peptide within one anterior pituitary cell.

Ontogenetic Development of the Specific [3H]Nitrendipine Binding Sites in the Rat Whole Brain

[3H]Nitrendipine binding sites are localized much more in the synaptosomal membrane than in the mitochondrial and microsomal membranes. To use a whole homogenate (crude membrane fraction) for the purpose of observing nitrendipine binding sites in the synaptosomal membrane instead of P2-B fraction has its reason. The Bmax of specific nitrendipine binding in the rat brain increases linearly until it reaches to the adult level after birth. High affinity binding at early developmental stages shifts to low affinity after the 7 day postnatal stage. Autoradiographically, nitrendipine binding sites are rich in the interpeduncular nucleus, olfactory bulb, hippocampus and superior colliculus in an adult rat. In autoradiography, the density in the hippocampus increases gradually until it reaches the adult level at the 28 day postnatal stage.

Cyclic Nucleotides in Progressive Muscular Dystrophy

The authors radioimmunoassayed cyclic nucleotide concentrations in plasma and biopsied muscles of muscular dystrophy and muscles of chicken embryo. c-AMP concentrations in plasma were significantly lowered in Duchenne-type muscular dystrophy and this lowered degree was correlated with the stage of progression. Plasma c-GMP levels were also depressed in Duchenne-type dystrophy. In biopsied muscles, c-AMP concentrations per milligram of non-collagen protein were within normal limits. Therefore, the decrease of plasma c-AMP concentrations might be an expression of total metabolic changes rather than a pathologic process of the muscle itself. As for the dystrophic chicken embryo, both c-AMP and GMP concentrations were decreasing in the pectoral muscles in parallel with the advancement of hatching stages.

Immunohistochemical Studies on Autopsied Organs of Familial Amyloid Polyneuropathy in Relation with Amyloid Protein

These days, much progress has been achieved on biochemical studies of amyloidogenesis and the relationship between clinical types and amyloid-proteins has been well documented.