Biomedical subjects

T Kitamoto

Publications and source records attributed to T Kitamoto.

At least 145 records · Page 8Linked to original sources

PubMed1991

A prion protein missense variant is integrated in kuru plaque cores in patients with Gerstmann-Sträussler syndrome.

Kuru plaques are the pathologic hallmark in Gerstmann-Sträussler syndrome (GSS). To demonstrate that prion protein (PrP) is a component of kuru plaque cores, we fractionated and sequenced kuru plaque core derived peptides, following digestion with Achromobacter lyticus protease I. We identified 3 PrP-derived peptides by reverse-phase high-performance liquid chromatography and found a fragment of digests derived from a missense variant of PrP. The variant PrP was also present in the prion rod fraction in patients with GSS. This substitution may play a major role in cerebral amyloidogenesis.

Amino Acid Sequence↗

PubMed1991

A comparative immunohistochemical study of Kuru and senile plaques with a special reference to glial reactions at various stages of amyloid plaque formation.

The authors examined 10 patients with Gerstmann-Sträussler syndrome or Creutzfeldt-Jakob disease and 10 with Alzheimer's disease (AD). Immunohistochemistry using anti-prion protein (PrP) and anti-beta/A4 protein (beta/A4) coupled with formic acid pretreatment could detect Congophilic and non-Congophilic deposits. Prion protein deposits were classified into five types and compared with types of beta/A4 deposits. Kuru plaques with multicentric cores and fine granular deposits were a characteristic feature of PrP deposits. Some types of PrP or beta/A4 deposits depend on the anatomic sites. To clarify the relationship of microglia and astrocytes to PrP or beta/A4 deposits, double-immunostaining method was performed. In both kuru and senile plaques, microglia were closely linked to the Congophilic plaques. Astrocytes, however, extended their processes toward the plaques even in the non-Congophilic plaques. These observations strongly suggest that similar glial association with plaque formation may be involved in both kuru and senile plaques, although the amyloid core proteins differ.

Alzheimer Disease↗

PubMed1991

Alzheimer's amyloid precursor protein-positive degenerative neurites exist even within kuru plaques not specific to Alzheimer's disease.

To clarify the relationship between amyloid formation and amyloid precursor protein (APP), the brain sections from eight patients with Alzheimer's disease (AD) and four with Gerstmann-Sträussler Syndrome (GSS) were investigated immunohistochemically by the double-immunostaining method. In AD, most APP-positive senile plaques belong to classical plaques or primitive plaques, whereas in diffuse plaques, APP-positive neuritic components are rarely observed. The authors documented that anti-APP-labeled degenerative neurites surrounding kuru plaques in all four GSS patients. These kuru plaques were verified by double immunostaining using anti-prion protein and anti-APP. The APP-positive structures in kuru plaques were almost identical with those seen in the classical plaques in AD. The authors concluded that APP-positive degenerative neurites are not an early event in the amyloid formation of senile plaques. It is therefore postulated that depositions of beta/A4 and prion proteins are primary events that may involve the surrounding microenvironment and result in the secondary formation of APP-positive degenerative neurites, not specific to AD.

Alzheimer Disease↗

PubMed1991

Hydrated autoclave pretreatment enhances tau immunoreactivity in formalin-fixed normal and Alzheimer's disease brain tissues.

We developed a new immunohistochemical method by which normal tau antigenicity can be visualized in paraffin sections of formalin-fixed brain tissue. This method consists of autoclave pretreatment of sections immersed into distilled water (hydrated autoclaving) before incubation with anti-tau antibodies. In normal human brain, immunoreactive tau was detected in neuronal cell bodies and dendrites, axon fibers, astroglia, oligodendroglia and gray matter neuropil. In previous studies on normal tau distribution, different optimized fixations that effectively preserve tau antigenicity were used but none of these revealed all of these compartments together. Our method is therefore considered to be more sensitive for detecting normal tau immunoreactivity. In addition, hydrated autoclaving had an enhancing effect on the abnormally phosphorylated (modified) tau immunoreactivity in formalin-fixed brains. In hydrated autoclaving of sections from patients with Alzheimer's disease, neuropil threads, senile plaques, extracellular and intracellular tangles were enhanced in quantity and in staining intensity. Therefore, modified tau appears to accumulate more densely than expected from conventional immunohistochemistry. Immunoblot analysis showed that normal or modified tau immunoreactivity was totally or partially eliminated on formalin treatment and could be revisualized by hydrated autoclaving, an event presumably related to recovering of formalin-masked tau antigens through denaturation by hydrated autoclaving.

Adult↗

PubMed1991

[Mutation of codon 117 of the prion gene in Gerstmann-Sträussler-Scheinker disease].

We report the clinical progression of the Gerstmann-Sträussler-Scheinker disease (GSS) in a family of Alsatian origin. The age of onset and duration of evolution were variable. The clinical picture became more complex over the generations: isolated dementia in the first generations, then, more recently, a triad of pyramidal, pseudobulbar syndrome and dementia associated with symptoms indicating spread of damage to the spinal cord and cerebellum. Study of the prion gene showed that in all patients analyzed and in 10 healthy family members, there is a double mutation of codon 117 leading to loss of the restriction site PvuII and to the replacement of an alanine by a valine. We did not find the mutation of codon 102 reported in 5 GSS families. The role of these mutations in the pathogenesis of the disease is unclear: marker for a particular susceptibility to the encephalopathies due to the prion, or direct role in the disease? Further study of the family, particularly the healthy carriers, could suggest the answer. GSS seems to be an especially useful model for the study of the role of a foreign abnormal protein in the synthesis and regulation of host proteins.

Chromosome Mapping↗

PubMed1990

Cerebral amyloid in mice with Creutzfeldt-Jakob disease is influenced by the strain of the infectious agent.

We examined Fukuoka-1 and Fukuoka-2 mouse-adapted Creutzfeldt-Jakob disease strains. Mice infected with the Fukuoka-2 strain have a higher incidence of kuru plaques, a higher concentration of proteinase-resistant prion protein, and a higher infectivity titer than do mice with the Fukuoka-1 strain. Thus, it must be kept in mind that there is a difference in the strain of the infectious agent in murine Creutzfeldt-Jakob disease.

Amyloidosis↗

PubMed1990

Creutzfeldt-Jakob disease patients with congophilic kuru plaques have the missense variant prion protein common to Gerstmann-Sträussler syndrome.

Congophilic kuru plaques, one of the pathological hallmarks in kuru and Gerstmann-Sträussler syndrome, are sometimes present in patients with Creutzfeldt-Jakob disease (CJD). The congophilic kuru plaques are composed partly of a host-encoded prion protein, and a missense variant prion protein with the codon 102 proline-to-leucine change (Leu102) is commonly present in patients with Gerstmann-Sträussler syndrome. To investigate the relationship between this syndrome and CJD with congophilic kuru plaques, we made a sequence analysis of the prion protein gene from patients with CJD, with or without congophilic kuru plaques. We found no alterations other than the Leu102 change, common to Gerstmann-Sträussler syndrome, in one of the prion protein alleles of the patient with congophilic kuru plaques. In the prion protein genotype analysis of other patients with CJD, the Leu102 allele was revealed to be carried heterozygously by 6 of 7 patients who had CJD with congophilic kuru plaques, yet no patient with CJD without congophilic kuru plaques had this allele. Interestingly, the Leu102 allele was also carried by some unaffected relatives of 3 patients with CJD with congophilic kuru plaques but with no apparent familial occurrence of a similar neurological disorder. Our findings show that CJD with congophilic kuru plaques should be categorized as belonging to Gerstmann-Sträussler syndrome, not CJD, and also suggest that the variant prion protein with Leu102 is closely related to the amyloidogenesis seen in subjects with congophilic kuru plaques.

Adult↗

PubMed1990

Immunogold light and electron microscopic detection of amyloid plaques in transmissible spongiform encephalopathies.

The antigenicity of the 'prion' protein amyloid fibrils was shown to be preserved after glutaraldehyde/OsO4 fixation in uranyl acetate-stained brain tissue blocks from patients with Gerstmann-Sträussler syndrome (GSS) and from mice infected with Creutzfeldt-Jakob disease (CJD). Amyloid plaques were demonstrated by light microscopy in immunogold silver-intensified semithin sections. Under the electron microscope, the amyloid fibrils were labelled in immunogold-reacted ultrathin sections using an antiserum prepared against GSS amyloid plaque cores and mouse amyloid fibrils respectively. The influence of various oxidizing agents (hydrogen peroxide, sodium metaperiodate) on the tissue preservation and the immunohistochemical detection was tested.

Amyloidosis↗

PubMed1990

Immunochemical, molecular genetic, and transmission studies on a case of Gerstmann-Sträussler-Scheinker syndrome.

Using immunostaining with anti-prion protein (PrP) antiserum, we detected numerous kuru plaques in the brain of a 24-year-old man with Gerstmann-Sträussler-Scheinker syndrome. Immunoreactivity on Western blotting of the protease-resistant PrP fraction from the frozen brain was weak. PrP gene analysis showed substitution of alanine to valine in codon 117 but no substitution in codon 102. As the experimental transmission of the disease to mice was negative, a pathogen of a relatively low infectivity may cause the disease in predisposed family members.

Adult↗

PubMed1989

Expression of cellular retinoic acid binding protein II (chick-CRABP II) in the chick embryo.

We previously demonstrated the presence of cellular retinoic acid binding protein II, chick-CRABP II, in chick embryos. In the present study, we investigated the distribution of chick-CRABP II in 14-day chick embryos by means of immunoblot analysis. Chick-CRABP II was expressed in skin, muscle, bone with tendon of the embryos, but not expressed in the nervous system. In adult chick tissues, chick-CRABP II was not detected on immunoblotting; Chick-CRABP II in adults amounts to less than 10 ng/mg soluble protein. These observations suggest that chick- CRABP II is an embryonic protein involved in the development of specific tissues, such as bone, muscle and skin.

Animals↗

PubMed1989

Pro----leu change at position 102 of prion protein is the most common but not the sole mutation related to Gerstmann-Sträussler syndrome.

The host-encoded prion protein (PrP) is a component of transmissible amyloid deposited in the brains affected by Gerstmann-Sträussler syndrome (GSS). Recently GSS in two unrelated Caucasian families has been reported to be linked to an amino acid change in PrP codon 102, proline to leucine (Leu102). However, it has not been clear whether the change is commonly found to GSS regardless of ethnic origin. We report here that Leu102 is also found in all the Japanese GSS patients tested. Interestingly, one French GSS patient was found to have another change, alanine to valine in codon 117 (Val117), instead of Leu102. Our results indicate that Leu102 is closely related to GSS irrespective of ethnic origin, but not the sole mutation related to GSS. Val117 may also be related to GSS.

Alleles↗

PubMed1989

Ferritin immunohistochemistry as a marker for microglia.

An immunohistochemical analysis of formalin-fixed, paraffin-embedded brain sections was performed with antisera against holoferritin and the light(L)-subunit of ferritin. Sections immunostained using anti-glial fibrillary acidic protein (GFAP), Ricinus communis agglutinin-1 (RCA-1) stain for microglia and iron stain (Berlin blue stain) were compared. The L-subunit of ferritin was purified from normal human spleen according to the modified scrapie-associated fibrils purification, and the anti-serum was raised in a rabbit. Both ferritin antisera positively stained resting and, more markedly, reactive microglia, both of which were also stained with RCA-1 but not with GFAP. Ferritin-positive resting microglia were seen more abundantly in cerebral and cerebellar cortices than in white matter. The advantages of ferritin antisera over RCA-1 are as follows. (1) RCA-1 heavily stains blood vessels, while anti-ferritin does not, hence the microglial cells are more readily visualized with ferritin immunohistochemistry. (2) Reactive microglia and macrophages are more strongly stained with anti-ferritin. (3) The staining intensity of ferritin is independent of the length of tissue fixation in formalin. However, anti-ferritin is inferior to RCA-1 in staining resting microglia with a scanty cytoplasm, especially in the white matter, probably because the former recognizes cytoplasmic components, while the latter recognizes cell membrane. Iron stain only gave a reaction to microglial cells in brains with neurosyphilis and to hemosiderin-laden macrophages. Thus, in addition to RCA-1, ferritin antisera are useful as a microglia marker in formalin-fixed, paraffin-embedded sections.

Brain↗

PubMed1989

Organ distribution of proteinase-resistant prion protein in humans and mice with Creutzfeldt-Jakob disease.

We attempted to clarify the organ distribution of human and murine proteinase-resistant prion protein (PrPCJD) in Creutzfeldt-Jakob disease (CJD), and to measure the concentration of PrPCJD, using a semi-quantitative Western blot analysis. Human PrPCJD was restricted to the central nervous system, whereas murine PrPCJD was present in the central nervous system and in the lymphoreticular system at the end stage of CJD. PrPCJD concentration in the central nervous system of mice was almost identical to that of humans. The minimum wet weight of an organ with a positive reaction was 0.3 mg for brain, 1 to 3 mg for spleen, 3 mg for spinal cord, 3 mg for lymph node, 10 mg for thymus and 10 to 30 mg for intestine of the CJD-infected mice. There were no immunoreactions in purified PrPCJD fractions from 300 mg of spleen, lymph node, liver or peripheral nervous systems of humans, nor in 300 mg of liver, lung or kidney of CJD-infected mice. Within the limits of our method, the distribution of murine PrPCJD differed from that of human PrPCJD. Antibodies on the Western blot membrane from murine spleen PrPCJD fractions stained the kuru plaques in the CJD-infected mouse brain. Therefore, PrPCJD in the murine spleen probably shares the epitopes of the antigen in the murine kuru plaques. Although the immunological detection of PrPCJD does have limits of sensitivity, PrPCJD concentrations did correlate with infectivity titres in scrapie-infected or CJD-infected mice.

Animals↗

PubMed1989

Beta-protein amyloid is widely distributed in the central nervous system of patients with Alzheimer's disease.

To clarify the distribution, morphology, and density of amyloid deposits in patients with Alzheimer's disease (AD), tissue sections from various areas of the central nervous system of 14 patients with AD and from 20 nondemented aged controls were investigated immunohistochemically using anti-beta protein antiserum. beta-protein amyloid deposits were present not only in the cores of the senile plaques and in the vascular wall (amyloid angiopathy), but also in various sized plaque-shaped fibrillary, perivascular, subpial, and subependymal deposits. Amyloid deposits were found mainly in the cerebral cortex in nondemented controls, while in AD they were distributed widely in the regions that were not affected in nondemented controls. The positivity of amyloid deposits in AD was 100% in the cerebral cortex, hippocampus, amygdala, thalamus, caudate nucleus, claustrum, hypothalamus, nucleus basalis of Meynert, and cerebellar cortex. Putamen and brain-stem nuclei were affected frequently, and the spinal cord, dentate nucleus, and globus pallidus were sometimes (less than 50%) affected. This result provides an evidence that Alzheimer's disease is a beta-protein amyloidosis of the central nervous system. An assessment of the distribution of amyloid deposits should prove to be useful for the histopathologic diagnosis of AD.

Aged↗

PubMed1989

Positive transmission of Creutzfeldt-Jakob disease verified by murine kuru plaques.

Kuru plaque is a pathognomonic feature in the brain of patients with Creutzfeldt-Jakob disease (CJD) and in the brain of CJD-infected mice. Kuru plaques from CJD-infected mice were immunolabeled with rabbit anti-murine prion protein (PrP) absorbed with human PrP, but not so with mouse anti-human PrP. Therefore, the murine kuru plaque is composed of the host (mouse) PrP and can be distinguished antigenically from human PrP. Immunostaining using the anti-murine PrP and formic acid enhancement on tissue sections revealed not only birefringent kuru plaques but also nonbirefringent diffuse and small PrP accumulations. This immunohistochemical detection of kuru plaques provides more positive evidence than heretofore employed histochemical approaches. There were kuru plaques in brains of the first passage mice inoculated with tissues from 30 (91%) of 33 patients with CJD, the 3 negative patients belonging to a type of Gerstmann-Sträussler syndrome. Tissues from 6 other demented patients did not produce kuru plaques. In the evaluation of spongiform changes, mice inoculated with tissues from 23 (70%) of 33 patients were considered cases of successful transmission. In some mice, kuru plaques were present in the absence of spongiform changes. Further inoculations from 9 mice with kuru plaques but no spongiform changes were successful in almost all mice. Therefore, mice with murine kuru plaques in the absence of spongiform changes are also infectious. Thus, the presence of murine-specific kuru plaques can serve as another hallmark of a successful transmission.

Adult↗

PubMed1989

Increased tau accumulation in senile plaques as a hallmark in Alzheimer's disease.

To identify the tau component in senile or kuru plaques, the authors examined brain sections from 12 patients with Alzheimer's disease (AD), 6 with Creutzfeldt-Jakob disease (CJD), and 20 nondemented aged controls using anti-beta protein, anti-buman prion protein, and affinity-purified tau-specific antibody. The tau component was identified both in senile and kuru plaques. In AD, tau-positive senile plaques were found in all cerebral cortices of almost all cases, and the tau-positivity of plaques in cerebral cortices was 5.1 to 27.5%. In CJD, tau-positive senile and kuru plaques were restricted to the hippocampus, and the tau-positivity was 4.3 and 1.2%, respectively. In nondemented aged controls, tau-positive senile plaques also were restricted mostly to the hippocampus, and the tau-positivity was 1.3%. Significant differences in the tau-positivity of senile plaques were found between AD and CJD and nondemented aged controls, and no significant differences were found between CJD and nondemented aged controls. These observations are important because increased tau accumulation in senile plaques can be a hallmark of AD.

Adult↗

PubMed1988

The presence of a novel cellular retinoic acid-binding protein in chick embryos: purification and partial characterization.

Two cellular retinoic acid binding proteins, CRABP I and II, which behaved differently on a DEAE-cellulose column, were purified from 14-day chick embryos. Their molecular weights were 15.8 kDa and 16.2 kDa, respectively. NH2-terminal 36 amino acid sequence of CRABP I was identical to that of bovine CRABP, which was reported previously. CRABP II was a novel cellular retinoic acid binding protein, in which the amino acids at 6 positions of the NH2 terminal sequence are different from those in CRABP I. The homology between CRABP I and II was more than 83%.

Amino Acid Sequence↗

PubMed1988

Structure of fatty acid synthetase from the Harderian gland of guinea pig. Proteolytic dissection and electron microscopic studies.

Limited proteolysis and electron microscopic observation of fatty acid synthetase from the Harderian gland of guinea pig was performed to elucidate the higher-order structures of this multifunctional protein. Staphylococcus aureus V8 protease dissected the 250,000 Mr subunit of fatty acid synthetase into 120,000, 70,000, 35,000 and 30,000 Mr fragments, which were aligned in this order from the NH2 terminus. Some of the protease-resistant fragments produced with elastase, trypsin and lysyl endopeptidase were purified and fragment-specific antibodies (A40L, A33E and A25T) were prepared. A25T and A33F specifically bound the 35,000 and 30,000 Mr fragments, and A40L recognized the region between the 120,000 and 70,000 Mr fragments. Electron microscopic studies employing rotary shadowing, unidirectional shadowing and negative staining revealed that the overall dimension of the enzyme was 22 nm x 15 nm x 7 nm, and that two elongated subunits mainly composed of three subregions were in contact with each other at a few, three at most, points with two holes between them. The outer two attachment sites were often not in contact, indicating a certain flexibility of subunits at their ends. Immunocomplexes composed of fatty acid synthetase and fragment-specific antibodies were isolated and observed under the electron microscope. The attachment sites of A40L and A33E were located at the end of the minor and the major axes of the ellipsoidal contour of the molecule, respectively. Based on these results, the three-dimensional structure of animal fatty acid synthetase is discussed.

Amino Acid Sequence↗