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Biomedical subjects

H Nakata

Publications and source records attributed to H Nakata.

At least 19 recordsLinked to original sources
PubMed1992

High levels of nervous system-specific proteins in cerebrospinal fluid in patients with early stage Creutzfeldt-Jakob disease.

Concentrations of several proteins that are characteristic of the nervous system were time-sequentially analyzed by radio- and enzyme-immunoassay in the cerebrospinal fluid (CSF) of patients with Creutzfeldt-Jakob disease (CJD). We found abnormally high levels of several proteins, such as neuron-specific enolase (NSE), S-100b protein, brain-type isozyme of creatine kinase (CK-BB) and alpha subunit of GTP binding protein G0 (G0 alpha) in the early stage of the disease. Generally, these protein levels were far higher in CJD patients than in normal controls and other neurological patients in the early stage before the typical clinical manifestations were evident. These levels increased to maxima when the disease activity was most prominent and returned to normal or mildly elevated levels in the terminal stage. The results imply that these protein levels can serve as biochemical markers for the presence of an active destructive process in CJD brain and provide us with a useful indicator for early diagnosis of CJD.

Brain↗
PubMed1992

Cloning and characterization of gastrin receptor from ECL carcinoid tumor of Mastomys natalensis.

We report here the cDNA cloning of a putative gastrin receptor from enterochromaffin-like (ECL) carcinoid tumor of Mastomys natalensis. For this study, we used the polymerase chain reaction technique to amplify transmembrane domain sequences related to rat pancreatic cholecystokinin (CCK)-A receptor from the ECL tumor cDNA library. The amino acid sequence deduced from the cloned cDNA showed 85.7% and 49.0% identity to canine parietal cell gastrin receptor and rat pancreatic CCK-A receptor, respectively. Ligand binding studies using COS-7 cells transfected with the cDNA showed the same binding specificity for gastrin and CCK-8 as the gastrin receptor on the Mastomys carcinoid tumor membrane. Both gastrin and CCK-8 elevated free cytosolic calcium concentration in COS-7 cells expressing the cloned receptor. RNA blot analysis revealed the expression of the gastrin receptor in both Mastomys stomach and brain.

Amino Acid Sequence↗
PubMed1992

[X-ray examination of the gastrointestinal tract in systemic cutaneous disease].

An X-ray examination of the gastrointestinal tract was performed on 56 patients with systemic cutaneous disease that is often considered associated with internal malignancies. Found were one case of esophageal cancer, two cases of gastric cancer, and two cases of colon cancer. The prevalence of gastric and colon cancer in these patients showed a statistically significant increase compared to the general population. The rate of gastric cancer was 16.26 times higher than the general population and that of colon cancer 32.26. X-ray examination of the gastrointestinal tract in patients with systemic cutaneous disease is useful for detecting malignancy.

Aged↗
PubMed1992

Biochemical and immunological characterization of A1 adenosine receptors purified from human brain membranes.

The A1 adenosine receptor was purified approximately 13,000-fold to apparent homogeneity from human cerebral cortex membranes using a novel affinity-chromatography system developed for the purification of rat brain and rat testis A1 adenosine receptors [Nakata, H. (1989) J. Biol. Chem. 264, 16,545-16,551; Nakata, H. (1990) J. Biol. Chem. 265, 671-677]. The purified human brain receptor showed the ligand-binding specificity expected of the A1 adenosine receptor. The Bmax and Kd for the purified receptor with a specific A1 adenosine receptor antagonist, 8-cyclopentyl-1,3-[3H]dipropylxanthine, were approximately 16 nmol/mg protein and 2 nM, respectively. SDS/PAGE of the purified receptor preparation showed one broad protein band of molecular mass of approximately 35 kDa, which is very similar to that of purified A1 adenosine receptor from rat brain membranes. Endoglycosidase F treatment of the purified receptor reduced the molecular mass to approximately 30 kDa, suggesting that the human brain A1 adenosine receptor is a glycoprotein. Comparison of the purified human and rat brain A1 adenosine receptors by peptide mapping after the proteolytic digestion showed minor differences between these receptors. Immunological comparisons of the human brain A1 adenosine receptor with rat brain A1 adenosine receptor using polyclonal antibodies against the purified rat brain A1 adenosine receptor showed that the antibodies react preferentially with the rat brain receptor and weakly with human brain receptor.

Adenosine↗
PubMed1992

Affinity chromatography in purification of A1 adenosine receptors.

Purification of A1 adenosine receptor of rat brain membranes was performed using a newly developed affinity gel employing xanthine amine congener (XAC) as an immobilized ligand. The A1 adenosine receptor was solubilized with digitonin-cholate from brain membranes and then purified by a sequential use of affinity chromatography on XAC-agarose, hydroxyapatite chromatography and reaffinity chromatography on XAC-agarose. The A1 adenosine receptor was purified ca. 45,000-fold with a yield of 5%. The final receptor preparation gave a single broad band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with a Mr approximately 34,000. This band was also shown to be specifically labelled with an affinity labelling reagent for A1 adenosine receptors. This purification method was also applicable for the complete purification of A1 adenosine receptors from rat testis and human brain membranes.

Animals↗
PubMed1992

Chymotrypsin-reactive antibodies in insulin-dependent diabetes mellitus.

In a previous study (Frazier et al., 1990), it was demonstrated that two patients with type 1 (insulin-dependent) diabetes mellitus had antibodies in their serum which reacted with four 29 kDa pancreas-specific proteins on two-dimensional immunoblots. This paper reports on the purification and identification of these pancreatic proteins. The protein with the pI closest to pH7 was purified through the use of ammonium sulfate fractionation and ion-exchange chromatography. Gel filtration chromatography established that the protein's molecular weight was closer to 25 kDa. Amino acid composition and sequence analyses demonstrated homology between the protein and chymotrypsin. It is suggested that an abnormal regulation of chymotrypsin activity might be related to antibodies formed in some diabetic patients.

Adolescent↗
PubMed1992

Rare point mutation at codon 301 and 969 of FMS/M-CSF receptor in acute myelomonocytic and monocytic leukemia.

We have investigated whether point mutations occurred at codon 301 or 969 of FMS (M-CSF receptor) in 19 patients with acute myelomonocytic (M4) and monocytic leukemia (M5). Nineteen peripheral blood and bone marrow blood samples collected from M4 and M5 patients were examined by using polymerase chain reaction and hybridization to allele specific oligonucleotide probes. Mutations at codon 301 and 969 of FMS were not detected in any samples. FMS gene mutations at codon 301 and 969 were rarely involved in M4 and M5 patients in Japan.

Amino Acid Sequence↗
PubMed1992

Effects of islet amyloid polypeptide (amylin) and calcitonin gene-related peptide (CGRP) on glucose metabolism in the rat.

In this study, we compared the effects of islet amyloid polypeptide (IAPP) and calcitonin gene-related peptide (CGRP) on glucose metabolism both in vivo and in vitro in the rat. Intravenous injection of rat CGRP caused a significant increase in plasma glucose concentration with a simultaneous increase in plasma insulin levels, whereas neither IAPP-NH2 nor IAPP-COOH had any effect. Moreover, intravenous infusion of CGRP decreased tolerance to intragastric administration of glucose (O-GTT) without altering plasma insulin levels, but again IAPPs had no effect. On the other hand, 125I-[Tyr0]rat CGRP specifically bound to the liver plasma membrane, and not only CGRP but also IAPP-NH2 dose-dependently displaced the specific binding of 125I-[Tyr0] CGRP, whereas IAPP-COOH had no effect. Conversely, CGRP as well as IAPP-NH2 but not IAPP-COOH evoked dose-dependent activation of adenylate cyclase in the membranes, and these effects were significantly inhibited by a CGRP receptor antagonist, human CGRP-I(8-37). However, neither CGRP nor IAPP-NH2 had any effect on glucose production in rat isolated hepatocytes. These results suggest that (1) IAPP-NH2 but not IAPP-COOH induces adenylate cyclase activation via CGRP receptors on rat liver plasma membranes, and (2) CGRP might not involve its action on the liver in the changes of glucose metabolism.

Amyloid↗
PubMed1992

Differences and similarities in albumin and red blood cell flows through cerebral microvessels.

The hypothesis that microvessels in brain parenchyma are continuously perfused by plasma but intermittently perfused by red blood cells (RBCs) was tested in awake Sprague-Dawley rats. The microvascular distribution volumes of radioiodinated serum albumin (RISA) and 51Cr- and 55Fe-labeled RBCs were measured for periods from 15 s to 30 min. Local cerebral blood flow (LCBF) was assessed by the iodoantipyrine technique. The RISA and RBC distribution volumes were constant in the 12 areas studied from 15 s onward. These data fit a model of continuous plasma flow with intermittent RBC flow (and thus support the hypothesis), but they are also consistent with other models, e.g., continuous flow of both plasma and RBCs through all perfused microvessels. In parallel with LCBF, microvascular blood volume varied greater than 10-fold among brain areas. Relative to arterial hematocrit, microvascular hematocrits were low, which indicates that the passage of RBCs through parenchymal microvessels is more rapid than that of RISA. This could be the result of both the Fahraeus effect and intermittent RBC flow.

Animals↗
PubMed1992

Squamous cell carcinoma of unknown origin in middle mediastinum.

We report a rare case of squamous cell carcinoma located in the middle mediastinum as a solitary mass. Histologically, lymphatic tissues remained together with nests of squamous cell carcinoma which were occupying the greater part of the mass. Examinations of the whole body failed to detect a primary site of the squamous cell carcinoma. It is considered that the carcinoma cells reflect metastasis from a primary-unknown carcinoma (most likely TO lung squamous cell carcinoma) or that they originated from benign epithelial inclusions in a mediastinal lymph node.

Carcinoma, Squamous Cell↗
PubMed1992

Cerebral glucose utilization and blood flow in adult spontaneously hypertensive rats.

Not only blood pressure but also behavioral activity, brain morphology, and cerebral ventricular size differ between young spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. This suggests that cerebral blood flow and cerebral metabolism may vary between these two rat strains. To test this hypothesis, we measured local cerebral glucose utilization in 31 brain areas of 26-30-week-old rats. Local cerebral blood flow was also assessed in these same areas. Cerebral glucose utilization was measured by the 2-deoxyglucose method; cerebral blood flow was determined by the iodoantipyrene method. In virtually all gray matter structures, the apparent rate of glucose utilization was lower in SHR than in normotensive WKY rats; the interstrain differences varied significantly among structures and were statistically significant (uncorrected t tests) in 14 of 28 gray matter areas. Local cerebral blood flow was fairly similar in the two rat strains. The coupling of blood flow to glucose utilization varied significantly among brain areas in normotensive WKY rats as well as in SHR. In a number of gray matter structures, the coupling of flow to metabolism differed between hypertensive and normotensive animals. These data suggest that for many brain areas, either glucose utilization or glucose partitioning differs between WKY rats and SHR.

Analysis of Variance↗
PubMed1992

[A case of cardiac sarcoidosis associated with various clinical symptoms and thrombocytopenia].

A 29-year-old man presented with acute onset of high fever, chest pain and dyspnea. Chest X-ray film showed diffuse interstitial shadows, a cavitary lesion in the left upper lung field and cardiomegaly, but no lymphadenopathy. Abdominal CT scan showed hepatosplenomegaly and multiple small low density areas in the liver and spleen. Electrocardiogram demonstrated multifocal ventricular premature beats and ventricular tachycardia. Cardiac catheterization revealed left ventricular aneurysms. Sarcoidosis was confirmed by lung and liver biopsy. Drug therapy of prednisolone and mexiletine resulted in clinical improvement of symptoms, signs and chest X-ray film, but platelet count decreased gradually. It is suggested that an immune mechanism of sarcoidosis may have been the cause of this thrombocytopenia.

Adult↗
PubMed1992

[Two cases of unclassified chronic myeloproliferative disorders].

Two cases of unclassified chronic myeloproliferative disorders (UCMPD), diagnosed by hematological, cytogenetic and DNA analyses, are described. Case 1: a 63 year old female was admitted because of leukocytosis (96,800/microliters) and splenomegaly. Hematological examinations revealed an increase of the granulocytes in the peripheral blood and bone marrow. The neutrophil alkaline phosphatase (NAP) score was 121. The patient developed blast crisis after 12 months of the chronic phase. Case 2: a 48 year old male was presented with fever and leukocytosis (20,000/microliters). Hematological examinations revealed an increase of granulocytes in the peripheral blood and bone marrow. The NAP score was 33. Maturation-arrest in granulocytic series and morphological abnormalities of marrow cells were not observed in the two cases. Cytogenetic analysis of bone marrow cells disclosed 46, XX, i (17 q) in case 1 and 47, XY, +8 in case 2. Southern blot analysis using 3' bcr probe and TransProbe-1 showed no bcr rearrangement. These cases are thought to be valuable in order to clarify the relationship between UCMPD and CMPD such as Ph1 negative chronic myelocytic leukemia and myelodysplastic syndromes.

Blast Crisis↗
PubMed1991

Receptors for gastrin on gastric carcinoid tumor membrane of Mastomys natalensis.

Specific binding sites for human gastrin I (gastrin) were identified in a crude membrane preparation from the gastric carcinoid tumor of Mastomys (Praomys) natalensis. The binding of 125I-gastrin to the carcinoid tumor membrane was saturable, and Scatchard analysis of the data revealed a single class of binding site with a dissociation constant of 139.2 pM and a maximal binding capacity of 23.5 fmol/mg protein. Gastrin and CCK8 equipotently and dose-dependently displaced the binding of 125I-gastrin to the membrane. GTP but not ATP decreased 125I-gastrin binding to the membrane, and removal of Mg2+ attenuated this inhibitory action of GTP. The GTP-induced reduction of 125I-gastrin binding was found to be due to a decrease in binding affinity without a change in binding capacity. These results clearly indicate the presence of specific binding sites for gastrin, probably coupled to guanine nucleotide-binding protein, in the carcinoid tumor membrane of Mastomys, and suggest that gastrin has possible biological actions on these tumors.

Adenosine Triphosphate↗
PubMed1991

Interleukin-1 enhances the response of osteoblasts to platelet-derived growth factor through the alpha receptor-specific up-regulation.

Both platelet-derived growth factor (PDGF) and interleukin-1 (IL-1) are produced by activated macrophages and are thought to contribute to bone remodeling, but their precise roles remain to be clarified. The interaction between PDGF and IL-1 was, therefore, studied in normal osteoblast-like cells (MC3T3-E1). The expression of alpha- and beta-PDGF receptors on MC3T3-E1 cells was detected by RNA blot analysis and confirmed by immunoblot analysis. PDGF-induced chemotactic as well as mitogenic activities were synergistically enhanced by either IL-1 alpha or IL-1 beta (40 units/ml) pretreatment in serum-free medium, although IL-1 alone did not show any detectable chemotactic activities. This biological enhancement by IL-1 was accompanied by a selective increase of alpha-PDGF receptor expression, following the augmentation of alpha receptor autophosphorylation and inositol phosphate hydrolysis induced by PDGF-AA. These findings suggest that PDGF and IL-1 are jointly involved in the bone-remodeling microenvironment as local coupling factors.

Blotting, Northern↗
PubMed1991

[Radiological diagnosis of splenic metastasis and its prevalence at autopsy].

CT and US findings of 7 cases of splenic metastases are described and the prevalence of splenic metastases at autopsy in 641 cases with malignant tumors were evaluated. Metastatic foci in spleen appeared mostly as poorly-defined low density masses on CT. Iodinated contrast material was administered in 2 cases, but no contrast enhancement was observed. US showed both hypoechoic and hyperechoic patterns. These appearances were nonspecific, but were similar to those of metastatic lesions in the liver which were often visible on CT associated with splenic metastases. At autopsy splenic metastases were found in 34 of 641 cases (5.3%). Gastric, colon, lung and ovarian cancers were most common primary tumors. However, the rate of splenic metastasis per tumor was highest in ovarian cancer (50.0%), followed by malignant melanoma (33.3%), colon cancer (16.2%) and gastric cancer (8.2%). Hepatoma which had the biggest number of autopsy cases in this series showed the lowest rate of splenic metastasis (0.8%).

Aged↗