Shiro Hariguchi

Abnormal distribution of cathepsins in the brain of patients with Alzheimer's disease

Formalin-fixed paraffin-embedded hippocampal sections of brains with early-onset and late-onset Alzheimers disease were studied immunohistochemically with antisera against cathepsin D and cathepsin B. In addition to the staining of neuronal perikarya, some of the senile plaques visualized by Bielshowsky silver staining and some of reactive astrocytes were positively stained with the antisera against cathepsin D and cathepsin B in brains with Alzheimers disease. Abnormal localization of cathepsin D and cathepsin B immunoreactivity in neuronal perikarya was observed in brains with early-onset Alzheimers disease. These findings demonstrate that the distribution of lysosomal proteases was altered in brains with Alzheimers disease, suggesting the primary and/or secondary involvement of the lysosomal proteases in the pathological process of Alzheimers disease.

Amyloid β-protein precursor deposition in rat hippocampus lesioned by ibotenic acid injection

Ibotenic acid was injected into 3 parts of the lateral rat hippocampus. The animals were sacrificed 100 days after treatment, and studied immunohistochemically. The lesioned side of the hippocampus was highly atrophic with extensive neuronal loss and gliosis. Although silver staining revealed no particular structures such as neurofibrillary tangles or senile plaques, globular and granular depositions of amyloid beta-protein precursor (APP) immunoreactivity was observed by immunostaining in the lesion with the monoclonal antibody (clone 22C11). Increased immunoreactivities of glial fibrillary acidic protein (GFAP) and ubiquitin were found in the lesioned area, while the immunoreactivities of microtubule-associated protein 2 (MAP2) and 200 kDa neurofilament subunit protein (NF-H) were diminished. The results indicate that APP deposition is formed in the lesioned area where neuronal degeneration is produced by ibotenic acid in rat hippocampus.

Lysosome instability in aged rat brain

The study of the age-dependent change in lysosomal enzyme activities of the cerebral tissue showed the significant increase of cathepsin D in the aged rat brain, while those of beta-glucuronidase and acid phosphatase remained unchanged. The subcellular distribution study of cathepsin D and beta-glucuronidase revealed the increased activity of these enzymes in the cytosolic fraction from the aged brain. In vitro incubation of the lysosome fraction from the aged rat brain resulted in more leakage of these two enzymes, indicating the instability of the lysosome in the aged brain, which resembled the effect of L-Leu-methyl ester to the lysosome.

Scales for Mental State and Daily Living Activities for the Elderly: Clinical Behavioral Scales for Assessing Demented Patients

In the diagnosis, treatment, and care of dementia patients in the senile stage, comprehensive evaluation of ability in daily life and mental function is needed. Using a simple behavioral rating scale for the mental states (NM scale) and activities of daily living (N-ADL) of the elderly, we evaluated 250 elderly subjects. According to the NM scale, the scores for subjects in whom the severity was clinically diagnosed were as follows: normal, 50-48; borderline, 47-43; mild dementia, 42-31; moderate dementia, 30-17; and severe dementia, 16-0. Screening for dementia and determining its severity were readily accomplished using the NM scale, and basic activities in the daily life of the elderly could be evaluated effectively using the N-ADL. There was a significant correlation (r = 0.863) between the Hasegawa dementia scale and the NM scale (p < 0.001), a significant correlation (r = -0.947) between intellectual function scores of the GBS scale and the NM scale, and a significant correlation (r = 0.944) between motor function score of the GBS scale and the N-ADL score. Evaluations of daily life activities can be made not only by psychiatrists and clinical psychologists, but by nonspecialists as well, because they are based on data obtained by observation of daily life behaviors; thus, assessment is appropriate both in clinical settings and in places of living.

Enzyme-linked immunosorbent assay for human autoantibody to glial fibrillary acidic protein: higher titer of the antibody is detected in serum of patients with Alzheimer's disease.

We have developed an enzyme‐linked immunosorbent assay (ELISA) to detect anti‐glial fibrillary acidic protein (GFAP) autoantibody in human sera. The ELISA was prepared by coating microtest plates with purified GFAP from bovine spinal cord. The autoantibody activities were assayed in the serum from 219 control subjects, 39 Alzheimers disease patients and 39 cerebrovascular dementia patients. Higher titer of the antibody was observed in the serum of Alzheimers disease patients. Since the titer showed no significant change with aging or with sex in the control serum, we could determine a certain normal value of the antibody titer. The percentage of abnormal subjects whose antibody levels were over the normal value was 53.8% in Alzheimers disease (presenile onset) patients, 30.8% in Alzheimers disease (senile onset) patients, 10.3% in cerebrovascular dementia patients and 5.5% in control subjects. We discuss the relationship between the anti‐GFAP autoantibody and the pathogenesis of Alzheimers disease and suggest that the evaluation of the anti‐GFAP autoantibody level may be useful in diagnosing Alzheimers disease.

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)

Age-dependent change in activities of lysosomal enzymes in rat brain

The age-dependent change in activities of seven lysosomal enzymes (cathepsin D, beta-glucuronidase, acid phosphatase, acid/alkaline DNases and acid/alkaline RNases) was studied in four brain regions (cerebrum, hippocampus, pons and cerebellum) of Wistar rats. The activity of cathepsin D was significantly increased with aging in the four regions. The age-dependent change in activities of acid and alkaline DNases showed the characteristic regional difference, and the ratio of acid to alkaline DNases was increased with aging in all regions. Acid RNase showed the lowest activity in 18-month-old rats, and alkaline RNase activity was decreased with aging. The activity of beta-glucuronidase was higher in 2-month-old rats in all of the regions studied. Acid phosphatase showed no significant age-dependent change except in pons. The study demonstrated that all of the lysosomal enzyme activities do not change in parallel with aging, and that the age-dependent change showed the characteristic regional difference.

Involvement of clathrin light chains in the pathology of Alzheimer's disease

Clathrin, which constitutes coated vesicles, plays important roles in neuronal functions. In the brains of the patients with Alzheimers disease, distribution of clathrin was immunohistochemically investigated using four monoclonal antibodies against clathrin light chains, LCB.1, LCB.2, X-16 and CON.1, to study the involvement of clathrin in the pathology of Alzheimers disease. LCB.1, LCB.2, X-16, and CON.1 bind to the aminoterminus of the clathrin light chain b(LCb), to the neuron-specific insert of LCb, to the light chain a(LCa), and to LCa and LCb, respectively. In Alzheimer brains, granular staining of LCB.2 around neurons in the hippocampus was weaker or patchily defected in comparison with control brains. Some neurofibrillary tangles and neurons were intensely stained in Alzheimer brains by LCB.2, whereas neurons were weakly stained in control brains. Crowns of some senile plaques in the brains of early onset Alzheimers disease were positively stained by LCB. 2. LCB. 1 supported the observations of LCB.2. Reactive astrocytes in Alzheimer brains were intensely stained by X-16. On the other hand, Western blot analysis using LCB.2 and X-16 demonstrated no apparent differences in protein amounts and molecular weights of LCa and LCb between control and Alzheimer brains. These observations demonstrated abnormal distribution of clathrin in Alzheimer brains, implying impairment of axonal transport in this disease.

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.

Involvement of clathrin light chains in the pathology of Pick's disease; impilication for impairment of axonal transport

Clathrin, which constitutes coated vesicles and plays important roles in neuronal functions, has been reported to be involved in the pathology of Alzheimers disease. In the brains of the patients with Picks disease, distribution of clathrin was immunohistochemically investigated using monoclonal antibodies binding to different epitopes of clathrin light chain a and b. All the antibodies intensely labeled Picks body and some perikarya of neurons, indicating impairment of slow axonal transport b (SCb). Antibodies against neurofilament, kinesin and synaptophysin also labeled Picks body. These observations suggested impairment of axonal transport in the brains with Picks disease, and might contribute to elucidating the pathology of Picks body forming. It is implied that common pathological processes might lie in Alzheimers disease and Picks disease.