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S Hariguchi

Publications and source records attributed to S Hariguchi.

27 records · Page 2Linked to original sources
PubMed1988

Activities of lysosomal enzymes in rabbit brain with experimental neurofibrillary changes.

Rabbits were injected intracerebrally with aluminum salt leading to experimental neurofibrillary change formation as a model of Alzheimer neurofibrillary change. Eleven days after the injection, the brain tissues were excised from the cortex, hippocampus, and cervical region of spinal cord. Five lysosomal enzymes (cathepsin D, beta-glucuronidase, acid phosphatase, acid DNase, alkaline DNase) were assayed and compared with the control. Cathepsin D, acid DNase and beta-glucuronidase activities increased significantly in all 3 areas of aluminum-injected brain. On the other hand, acid phosphatase and alkaline DNase activities remained at the same level. The results showed the lysosomal enzymes did not change in parallel after aluminum administration, suggesting a role of the increased enzymes in the brain with neurofibrillary changes.

Acid Phosphatase↗
PubMed1988

Neurofilament degradation by bovine brain cathepsin D.

The effect of cathepsin D on bovine neurofilament protein was studied biochemically, immunologically, and morphologically. Degradation products of each neurofilament triplet by bovine brain cathepsin D at neutral pH were identified by electrophoresis and immunoblotting with anti-neurofilament antibodies. The 68-kDa subunit was the most susceptive to cathepsin D proteolysis among the triplet proteins. All of the triplet gave rise to partial degradates of the 50-kDa size. The reconstituted fiber from neurofilament triplet proteins and the 68-kDa subunit protein were attacked by cathepsin D and the mode of disruption of the fiber structure was studied by electronmicroscopy.

Animals↗
PubMed1987

Histaminergic neuromodulation of the release of vasopressin.

In an attempt to clarify the nature of histaminergic neuromodulation of the vasopressinergic system, several studies under different experimental paradigms were carried out. L-Histidine loads (8 mmol/kg, i.p.) induced a marked increase in histamine (HA) in the anterior (AHR) and posterior (PHR) hypothalamic regions, the median eminence (ME) and adenohypophysis (Ah) with no apparent effect on the concentration of HA in the neurohypophysis (Nh), as measured by high-performance liquid chromatography. These findings correlated with decreases in vasopressin (VP) levels in the AHR and ME, accompanied by increases of the neuropeptide in the PHR and Ah. Intraperitoneal injections of HA (6 mumol/kg), resulted in a significant (p less than 0.005) rise in VP levels in the PHR, ME and Ah. HA induced an elevation of VP in the prefrontal cortex (PFC) from 6.23 +/- 2.02 to 43 +/- 4.05 microU/mg, as well as a 60% reduction in neurohypophyseal VP. These HA-induced VP responses were abolished by both mepyramine (3 mumol/kg) and famotidine (4 mumol/kg) in the PHR and PFC. Mepyramine suppressed the HA-induced VP response in the Ah and enhanced it in the Nh, while famotidine did the opposite. When alpha-fluoromethylhistidine (FMH), an irreversible inhibitor of histidine decarboxylase, was administered at doses of 100 mg/kg/day (i.p.), hypothalamic HA levels fell by 40-45% after 1 h, by 50% after 3 h, and by 65-80% after 24 h in adrenalectomized rats. In the same conditions, but after a week of treatment with FMH, the VP response to adrenalectomy was clearly impaired.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1969

[Dementia].

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Dementia↗
PubMedDate not supplied

Cell-cycle-dependent abnormal calcium response in fibroblasts from patients with familial Alzheimer's disease.

Change in calcium response was studied to clarify the pathological process of Alzheimer's disease (AD). Cultured fibroblasts from patients with familial Alzheimer's disease (FAD; n = 6), sporadic Alzheimer's disease (SAD; n = 4), and age-matched healthy control subjects (n = 4) were studied with an ACAS Interactive Laser Cytometer (ACAS-470). Fibroblasts from two independent families with FAD (OS-1, and OS-2 families) showed a suppressed calcium response after stimulation by 100 nM bradykinin (BK) 100 nM vasopressin (VP) or 10% FCS in Ca(2+)-free condition compared with control fibroblasts at 48 h after plating. However, on the 7th day after plating, the abnormal calcium response was no longer observed. The height of the calcium peak showed periodic variation, indicating a relationship of calcium response with the cell cycle. When fibroblasts from OS-1 and OS-2 families were arrested in S phase, they showed a significantly suppressed calcium peak after BK stimulation. However, when those fibroblasts were arrested in other phases, they showed the same calcium peak as the other cells. The suppression of calcium response in S phase was indistinguishable from the calcium suppression induced by A23187 administration. Since Hardy type mutation on amyloid precursor protein gene is found in the OS-1 family, the observed abnormalities in calcium response might be related with pathological processing of amyloid precursor protein in AD. The reported abnormal calcium response, which is observed most obviously in fibroblasts in S phase, may indicate participation of the cell-cycle-dependent process in the pathology of AD.

Adult↗