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Biomedical subjects

R Nakamura

Publications and source records attributed to R Nakamura.

At least 163 records · Page 9Linked to original sources
PubMed1995

Identification of activins and follistatin proteins in human follicular fluid and placenta.

Follistatin, an activin-binding protein, is able to neutralize the various activities of activin by forming an inactive complex with it. The widespread tissue localization of follistatin is very similar to that of activin, which suggests that it plays a local modulatory role in the various paracrine/autocrine actions of activin. We detected significant activin-binding activities in human follicular fluid and placental homogenates, although they were much lower than those in porcine and bovine follicular fluids, which raised the possibility that follistatin is present in human follicular fluid and placenta. Therefore, we attempted to identify the protein molecules responsible for this activin-binding activity in human follicular fluid and placental homogenates. Human follicular fluid, collected from in vitro fertilization patients, was processed by affinity chromatography successive steps on sulfated gel matrices and reverse phase high performance liquid chromatography (HPLC). The final HPLC yielded abundant follistatin and almost equimolar amounts of activin-A, -AB, and -B. The follistatin protein showed characteristic multiple bands when analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The ability of each band to bind activin specifically was determined by activin binding assay and ligand blotting analysis. Several pieces of evidence, including the immunoblotting analysis and functional assay results, demonstrated the presence of three activin isoforms, A, AB, and B, in the follicular fluid. In contrast, human placental homogenates were found to contain follistatin and activin-A proteins only. Activin-AB and -B were not detected in any HPLC fraction, indicating that activin-A is the major form of activin in the human placenta. The present data indicate that the three activin isoforms and multiple forms of follistatin exist in human follicular fluid, and the activin-A isoform and follistatin exist in human placenta. They suggest that the physiological functions of the activin isoforms during embryonic development differ and that follistatin plays a functional role in the local control system(s) that regulates human reproduction.

Activins↗
PubMed1995

Does bacitracin have an absorption-enhancing effect in the intestine?

We studied the absorption enhancement effects of three types of protease inhibitors, aprotinin, bacitracin and soybean trypsin inhibitor, in the rat intestine. Of these protease inhibitors, bacitracin enhanced the absorption of FD-4 and phenol red from the rat small and large intestine without mucosal toxicity. Thus, it was suggested that bacitracin has not only a protease-inhibitory but also an absorption-enhancing capability.

Animals↗
PubMed1995

Four rice seed cDNA clones belonging to the alpha-amylase/trypsin inhibitor gene family encode potential rice allergens.

Four rice seed proteins encoded by cDNAs belonging to the alpha-amylase/trypsin inhibitor gene family were overexpressed as TrpE-fusion proteins in E. coli. The expressed rice proteins were detected by SDS-PAGE as major proteins in bacterial cell lysates. Western blot analyses showed that all the recombinant proteins were immunologically reactive to rabbit polyclonal antibodies and to a mouse monoclonal antibody (25B9) specific for a previously isolated rice allergen of 16 kDa. Some truncated proteins from deletion mutants of the cDNAs retained their reactivity to the specific antibodies. These results suggest that the cDNAs encode potential rice allergens and that some epitopes of the recombinant proteins are still immunoreactive when they are expressed as their fragments.

Allergens↗
PubMed1995

Isolation and culture of bovine mammary epithelial cells and establishment of gene transfection conditions in the cells.

Bovine mammary epithelial cells (BMEC) were isolated as acinous fragments from a mammary gland of a lactating cow. They grew well on plastic substratum, showed the characteristic cobblestone morphology of epithelial cells, and secreted alpha s1-, beta-, and kappa-caseins even when grown on plastic substratum. A plasmid containing the bacterial chloramphenicol acetyl transferase (CAT) gene was transfected to the isolated BMEC by calcium phosphate precipitation and electroporation methods. The transfection efficiency of BMEC by the calcium phosphate method was greatly improved by post-transfection osmotic shock with glycerol or polyethylene glycol. An about 700 bp DNA fragment containing 5'-flanking sequence of bovine alpha s1-casein gene showed promoter activity in the transfected BMEC. The primary culture of BMEC might be useful for studies on regulation of bovine milk-protein gene expression.

Animals↗
PubMed1995

Fitness of the formulae of simplified version of recovery evaluating system-3 (RES-3) for stroke patients.

Using the formulae for prediction of functional status at 4, 8 and 12 weeks after admission in the stroke patient (simplified version of Recovery Evaluating System-3; RES-3) and demographic data at the admission of 128 stroke patients, the estimated scores of four measures, Motor Age Score (MOA), Manual Function Score (MFS), Barthel Index (BI) and Mini-Mental State (MMS), were obtained. Fitness of the formulae was tested in terms of the agreement between the estimated and the measured scores. The results indicated that the differences between the measured and the estimated scores were statistically not significant except BI. The measured scores of BI were 3 to 5 points high compared to the estimated ones. When the confidence limits of the differences were examined at a confidence coefficient of 95%, they were within 5% of the full score for MOA, MFS and MMS, and were within 10% for BI. Accordingly, by setting the allowable limit to 5% of the full score around the means, the fitness of prediction would be more than a probability of 95%. The formulae of simplified version of RES-3 were practically useful.

Adult↗
PubMed1995

Magnetic resonance imaging of multiple brain abscesses of the bilateral basal ganglia.

A 64-year-old woman developed multiple brain abscesses of the basal ganglia associated with Klebsiella pneumoniae septicemia. Magnetic resonance (MR) images showed three different stages of the brain abscesses. The images of early cerebritis of this site mimicked lacunar infarctions or dilated Virchow-Robin spaces. The differentiation of the brain abscess from lacunae and dilated Virchow-Robin spaces is discussed, together with the evolution of the brain abscesses on MR images.

Basal Ganglia↗
PubMed1995

[A case of urachal carcinoma associated with elevated levels of CA19-9].

A 53-year-old man was admitted with the chief complaint of gross hematuria. Cystoscopic examination revealed a non-papillary tumor at the dome of the bladder. The plasma level of CA19-9 was markedly elevated before treatment. Total cystectomy with en bloc removal of the tumor and radical lymphadenectomy were performed under the diagnosis of urachal carcinoma. The plasma CA19-9 level decreased to the normal level after operation and was well correlated with postoperative course. The monitoring of CA19-9 may be useful for follow up in patients showing a high elevation of CA19-9.

Adenocarcinoma↗
PubMed1995

A case of massive adrenal malignant pheochromocytoma: management of a large pheochromocytoma.

A 69-year-old man was referred to our hospital for a left abdominal tumor measuring about 30 cm in diameter. Laboratory examination revealed an elevation of norepinephrine in plasma and of its metabolites in urine. CT scan disclosed a huge cystic tumor in the retroperitoneal space and an enlarged aortocaval lymph node, suggesting a diagnosis of malignant pheochromocytoma. The hemodynamic studies showed low blood volume and high vascular resistance, and therefore, he was treated with vasodilators and volume expansion. His hemodynamic status normalized and a complete excision was performed. Pathological examination revealed that the patient had a pheochromocytoma with metastasis to a lymph node. The total weight of the tumor was 5,930 g. Since pheochromocytomas can become a large with a risk of malignancy, they should be surgically excised as completely as possible with further treatment after making a definite diagnosis.

Adrenal Gland Neoplasms↗
PubMed1995

Structural and functional differences of subspecies of apoA-I-containing lipoprotein in patients with plasma cholesteryl ester transfer protein deficiency.

ApoA-I-containing lipoproteins exist in plasma in two main forms: one contains only apoA-I (LpA-I) while the other contains both apoA-I and apoA-II (LpA-I/A-II). We characterized structural and functional changes of these lipoproteins in six patients with cholesteryl ester transfer protein (CETP) deficiency. In these patients, the amount of LpA-I and LpA-I/A-II had increased significantly. Sixty-five percent of plasma apoA-I was associated with LpA-I/A-II, which indicated that LpA-I/A-II was predominant. The chemical composition of both LpA-I and LpA-I/A-II was characterized by increased ratios of neutral to polar lipid, compared with findings in normal subjects. Particle sizes of these lipoproteins shifted to larger diameter ranges, as compared to the size seen in normal subjects. Incubation of patients' LpA-I and LpA-I/A-II with CETP markedly corrected the chemical and physical abnormalities in these lipoproteins. Cholesterol-reducing capacities of these lipoproteins from macrophage foam cells were significantly lower than in normal controls. Cholesterol esterification rates in LpA-I, LpA-I/A-II, and plasma were significantly lower in patients than in normal controls. We propose that the structure and function of LpA-I and LpA-I/A-II are severely affected in the presence of CETP deficiency.

Apolipoprotein A-I↗
PubMed1995

[A pharyngeal carcinoma after resection of a upper esophageal web].

Dysphagia suddenly progressed in a 69-year-old woman who had a 50-year history of intermittent difficulty in swallowing solid food. A thick circumferential who in the upper esophagus was extensive enough to be the cause of dysphagia. There was another thin semicircular web in the pharynx. Bouginage resulted in only 6-months relief of symptoms, and the same esophageal who was reformed with the same severe symptoms 3 years later. Surgical resection of the esophageal web was performed. Extensive pharyngeal carcinoma was found 4 years after surgery. She died of heart failure during combination therapy of irradiation and chemotherapy.

Aged↗
PubMed1995

Changes in wound healing factors in liver cirrhosis after esophageal transection for esophageal varices.

Quantitative changes in plasma wound healing factors in cirrhotic patients after esophageal transection were evaluated and compared with those of non-cirrhotic esophageal cancer patients (controls) after esophageal resection. Serum total protein, albumin and fibronectin were maintained at the same levels as those in controls when multiple units of fresh frozen plasma and albumin products were employed. Nevertheless, the principle protease inhibitors including alpha-1-antitrypsin and alpha-1-acid-glycoprotein showed little increase by the 3rd postoperative day, while those of controls increased as much as twofold at this time. Levels of complements C3 and C4 showed consistent depression, with little change during the study period. We conclude that the levels of some of the plasma proteins essential in wound healing are depressed in cirrhotic patients during the critical period after surgery.

Blood Proteins↗
PubMed1994

Late-onset selective neuronal damage in the rat spinal cord induced by continuous intrathecal administration of AMPA.

Neurotoxicity mediated by 1-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) was investigated by infusing this agent continuously for 7 days intrathecally to adult rats using a mini-osmotic pump. Behavioral changes were apparent only after the second postoperative day, when the rats displayed hindlimb palsy or incontinence of urine. The behavioral deficits became progressively severe and the rats usually displayed both hindlimb paraplegia and incontinence of urine by the 7th postoperative day. These progressive behavioral deficits were induced in a dose-dependent manner in the rats that received AMPA at a dose of > 100 pmol/h (100 microM at 1 microliter/h, 17 nmol in total dose). The severity of behavioral deficits was in parallel with that of neuropathological changes in the lumbosacral cords. In spinal segments rostrally adjacent to those with severe pathological changes, only the neurons in the dorsal horns (Rexed's laminae II-IV) were destroyed with intense gliosis. These changes were not induced by infusing AMPA for 1 day. The concomitant administration of 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), an antagonist for non-N-methyl-D-aspartate (NMDA) receptors, with AMPA, but not that of 2-amino-5-phosphonovalerate (APV), an antagonist for NMDA receptor, prevented induction of the behavioral and neuropathological changes. The findings of the present study suggest that this late-onset, selective neurotoxicity is mediated by AMPA-type glutamate receptors.

Animals↗
PubMed1994

Evidence for impaired cellular cholesterol removal mediated by apo A-I containing lipoproteins in patients with familial lecithin: cholesterol acyltransferase deficiency.

We investigated the cholesterol reducing capacity of two species of lipoproteins containing apo A-I, one containing only apo A-I (LpA-I) and the other containing apo A-I and apo A-II (LpA-I/A-II), in 7 patients (4 homozygotes and 3 heterozygotes) with familial lecithin: cholesterol acyltransferase (LCAT) deficiency. Interaction of normal LpA-I or LpA-I/A-II with macrophage foam cells induced a mass reduction in cholesterol from these cells and the cholesterol reducing capacity of LpA-I was greater than that of LpA-I/A-II. When foam cells were incubated with these lipoproteins from homozygotes or heterozygotes, the capacity of LpA-I and LpA-I/A-II particles to reduce cellular cholesterol was decreased by approx. 50% in the homozygotes but was increased by 25-50% in the heterozygotes. These results suggest that LpA-I and LpA-I/A-II isolated from homozygotes and from heterozygotes differ in their ability to accept cellular cholesterol. The former are poor and the latter good acceptors of intracellular cholesterol. We conclude that factors other than reverse cholesterol transport via apo A-I containing lipoproteins have to be considered to explain why homozygotes for LCAT deficiency are not at high risk for premature atherosclerosis.

Adult↗
PubMed1994

Immunologically cross-reactive 57 kDa and 53 kDa glycoprotein antigens of bovine milk fat globule membrane: isoforms with different N-linked sugar chains and differential glycosylation at early stages of lactation.

Two glycoprotein antigens with molecular masses of 57 kDa (MGP57) and 53 kDa (MGP53) were co-purified from bovine milk fat globule membrane (MFGM) by immunoaffinity chromatography using a monoclonal antibody raised against the MFGM. Their N-terminal sequences of 22 amino acids determined were identical, and the sequence was homologous (about 60% identical) to the deduced amino acid sequence of mouse milk fat globule epidermal growth factor (EGF) factor 8 (MFG-E8) (Ref. [12], Stubbs, J.D. et al., Proc. Natl. Acad. Sci. USA, 87, 8417-8421, 1990). This suggests that MGP57/53 are bovine MFGM components 15/16 (PAS-6 and PAS-7), which have recently been reported to be bovine homologs of MFG-E8. N-Glycanase treatment of these glycoproteins reduced their molecular masses, and consequently the enzymatically deglycosylated MGP57 and MGP53 converged on a single band of 50 kDa as measured by SDS-PAGE, indicating that the polypeptide portions of these two distinct glycoprotein antigens are very similar or identical and that their N-linked sugar chains contributed to minor difference in their molecular masses. Western blot analyses using lectins also revealed that they were differentially glycosylated; MGP57 was stained with concanavalin A (Con A) more strongly than MGP53, whereas MGP 53 was stained well with soybean agglutinin (SBA). Reactivity with SBA remarkably increased during early stages of lactation. Two-dimensional gel electrophoresis showed that MGP57 and MGP53 were electrically heterogeneous; from day 9 after parturition, both glycoproteins fell in almost the same range of isoelectric points between 6.4 and 7.6, also, such glycoproteins from day 1 after parturition were more acidic, probably due to terminal sialylation of their sugar chains.

Amino Acid Sequence↗
PubMed1994

Dystrophin-related protein is found in the central nervous system of mice at various developmental stages, especially at the postsynaptic membrane.

Dystrophin deficiency is known to be the cause of X-linked Duchenne muscular dystrophy (DMD). A recently cloned B3-cDNA shares 80% homology with the C-terminus and actin-binding portion of dystrophin. This autosome-derived gene product is called dystrophin-related protein (DRP). DRP is known to exist in fetal muscles even in mdx mice, an animal model for X-linked DMD, but not in mature mouse muscles. We raised a polyclonal antibody against a B3-unique amino acid sequence (Ab-LDP) and investigated the existence and distribution of DRP in the central nervous system (CNS) tissues of mdx and normal control B10 mice at various stages of development using immunoblotting and immunohistochemical methods. The former shows that DRP exists in the CNS of both B10 and mdx mice, regardless of the developmental stage, with the exception that the 420 kDa DRP band of the 15-day fetus is faint. In immunohistochemical studies, the choroid plexus, some neurons, glial cels, pia mater, and blood vessels were stained with Ab-LDP. Staining intensity did not differ between B10 and mdx mice or between developmental stages except that the 15-day fetus stained only faintly. This is in contrast to the results obtained for muscles in which DRP localized to muscle membrane in embryo decreases and is assembled at the neuromuscular junction in adults. In addition, an electron microscopic study on the cerebral cortex from adult B10 mice was also performed and revealed Ab-LDP staining of the postsynaptic membrane of dendrite and the rough endoplasmic reticulum of neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

Production and characterization of monoclonal antibodies directed against bovine milk fat globule membrane (MFGM).

Nine hybridomas secreting monoclonal antibodies (mAbs) to bovine milk fat globule membrane (MFGM) were produced from spleen cells of three immunized BALB/c mice. Several MFGM antigens recognized by some mAbs were identified as a 120 kDa protein and 67 kDa (butyrophilin), 57 kDa (PAS-6), 53 kDa (PAS-7), 33 kDa glycoproteins. The other mAbs secreted by four independent hybridoma clones recognized many broad bands ranging from 20 to 200 kDa. The 120 kDa protein and 67 kDa, 57 kDa, 53 kDa glycoproteins were detected by each mAb in the plasma membrane fraction prepared from a lactating bovine mammary gland. Moreover, mammary gland epithelium of a thin section was specifically stained with these mAbs, indicating that these mAbs directed against MFGM recognized membrane proteins and glycoproteins of lactating mammary epithelial cells. Upon heating of the MFGM in phosphate buffer, pH 7.4 at 100 degrees C for 10 min, the antigens still retained most of its reactivity to these mAbs, whereas, proteolytic cleavage by trypsin and chymotrypsin strongly reduced its reactivity to these mAbs by 60% or more except for two mAbs which recognized the 57 and 53 kDa glycoproteins, respectively.

Animals↗
PubMed1994

Role of fine needle aspiration cytology and endoscopic biopsy in the preoperative assessment of pancreatic and peripancreatic malignancies.

Sixty-seven of 207 patients with pancreatic and peripancreatic malignancies underwent preoperative fine needle aspiration cytology (FNA), and 24 patients underwent intraluminal endoscopic biopsies. All patients had confirmation of the diagnosis of malignancy either at operation, autopsy, or by clinical follow-up. FNA of liver metastases was positive for malignancy in 12 of 12 patients. FNA of the pancreas was performed on 44 patients with pancreatic adenocarcinoma and 11 patients with other pancreatic or peripancreatic malignancies. The diagnosis of cancer was established by FNA in 32 of 44 (72.4%) patients with pancreatic adenocarcinoma and 1 of 11 patients (9.1%) with other pancreatic or peripancreatic malignancies. In the patients with pancreatic adenocarcinoma, 17 of 18 patients (94.4%) who had no operative intervention, 12 of 18 (66.7%) patients who had palliative bypass procedures, and 3 of 8 (37.5%) patients resected had positive FNA. Eighteen of 24 patients (75%) who underwent intraluminal endoscopic biopsies, and 11 of 15 (73.3%) with ampullary carcinoma were positive. We believe that FNA is of limited value in the diagnosis of small resectable tumors of the pancreas as it identified cancer in only 3 of 8 patients in whom it was employed. False negative FNA may delay the diagnosis and treatment of pancreatic malignancies. Patients in whom there is a high index of suspicion of pancreatic or peripancreatic malignancy based on clinical presentation, CT scan, or ERCP assessment do not require preoperative, histologic proof of malignancy prior to pancreaticoduodenectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy, Needle↗