Biomedical subjects
Publications and source records attributed to K Yamazaki.
A 48-year-old man was admitted because of bloody sputum in whom a chest computed tomography (CT) scan and fiberoptic bronchoscopy demonstrated a polypoid tumor in the left main bronchus. The tumor was surgically resected, and the pathological and immunohistochemical findings led to diagnosis of the tumor as a bronchial glomus tumor.
Injury of endothelial cells has been assumed to be an initial trigger of the development of atherosclerosis. In this study, we investigated the molecular mechanisms of endothelial cell death induced by hypoxia, which leads to oxidative stress. To study the relation between hypoxia-induced cell death and activation of nuclear factor-kappaB (NF-kappaB) in a hypoxic state, we evaluated the effect of 2 antioxidant drugs, probucol and pyrrolidine dithiocarbamate (PDTC), on human endothelial apoptosis. Although hypoxic treatment of human aortic endothelial cells resulted in a significant decrease in cell number and a significant increase in apoptotic cells compared with that of cells under normoxia (P<0.01), treatment with probucol (50 micromol/L) or PDTC (100 micromol/L) significantly attenuated the decrease in cell number (P<0.01) and was accompanied by inhibition of NF-kappaB activation. Furthermore, downregulation of bcl-2 caused by hypoxia was inhibited by these drugs. We further investigated the translocation of bax protein from the cytoplasm to the mitochondrial heavy fraction membrane, as translocation of bax protein is considered to be a determinant of apoptosis. Interestingly, we found that antioxidant treatment inhibited the translocation of bax protein caused by hypoxia. Moreover, upregulation of p53, a proapoptotic molecule, was observed in hypoxia, whereas treatment with probucol attenuated the expression of p53 accompanied by suppression of NF-kappaB activation. These data suggest functional links between p53 and endothelial apoptosis through the activation of NF-kappaB. Overall, the current study demonstrated that oxidative stress induced apoptosis in human aortic endothelial cells through the downregulation of bcl-2, translocation of bax, and upregulation of p53, probably through NF-kappaB activation. Oxidative stress may play an important role in endothelial apoptosis mediated by hypoxia, through the activation of NF-kappaB.
Somatic mutations of the MEN type 1 (MEN1) gene were recently shown to be responsible for tumorigenesis in 13-26% of sporadic, nonfamilial primary hyperparathyroidism. However, it is unknown whether these mutations are also involved in tumorigenesis of parathyroid glands occurring during high phosphate therapy for hypophosphatemic rickets or osteomalacia. A male patient with adult-onset, hypophosphatemic osteomalacia had been treated with 1alpha-OHD3 and oral phosphate for 13 yr when tertiary hyperparathyroidism developed. After total resection of four enlarged parathyroid glands and autotransplantation of a hyperplastic gland, the patient has continued to do well for the last 2 yr. Sequence analysis of the coding exons of MEN1 gene revealed a 36-bp deletion with a 2-bp insertion (exon 2) in the right upper parathyroid gland accompanied with loss of heterozygosity at 11q13 locus and a heterozygous mutation of 2-bp deletion (AG) in exon 10 in the right lower gland, in which microsatellite instability was also found. No MEN1 gene mutation was detected in the other two hyperplastic parathyroid glands or in the peripheral blood. These findings indicate that MEN1 gene mutations contributed to tumorigenesis of the right upper parathyroid gland in this case of phosphate-induced tertiary hyperparathyroidism. Very recently a bone tumor was found in the right femoral neck, and the tumor (chondroblastoma) was resected.
Three NMR structures of alpha-conotoxin MI, a potent antagonist of the nicotinic acetylcholine receptor, have been refined using molecular dynamics (MD) simulation with explicit water. Although the convergence of the NMR structures of alpha-conotoxin MI was not sufficient to provide detailed structural features, the average structures obtained from MD simulations converged to one conformation, providing structural characteristics. The resulting structure was also found to be consistent with the results of amide proton-exchange experiments. These results demonstrate that MD simulation with explicit solvent water is very useful in refining NMR structures.
A healthy 58-year-old woman presented with recurrent swelling and pain of the nose and both auricules. Bruits were heard over both carotid arteries. Magnetic resonance angiography revealed stenosis of both internal carotid arteries. Relapsing polychondritis was diagnosed. These symptoms improved after treatment with prednisolone and azathioprine. Although relapsing polychondritis is sometimes associated with systemic vasculitis, large vessel arteritis is rare and can negatively affect prognosis. We conclude that the detection of systemic vascular lesions, including those involving the central nervous system, can play an important role in the diagnosis of relapsing polychondritis and that early treatment is essential for a good outcome.
BACKGROUND: Early-onset periodontitis (EOP) is considered to have a genetic basis, which has not been clearly defined. The tumor necrosis factor-alpha (TNF-alpha) gene polymorphism as one of the genetic factors may influence the expression of several chronic inflammatory diseases. The aim of the present study was to evaluate whether the polymorphisms in the 5'-flanking region of the TNF-alpha gene are associated with Japanese EOP patients. METHODS: Forty-six Japanese, generalized EOP (G-EOP) patients and 104 Japanese healthy subjects were identified according to established clinical criteria. Twenty healthy subjects were analyzed by nucleotide sequence to screen polymorphisms of the 5'-flanking region of the TNF-alpha gene. Then, all subjects were analyzed by polymerase chain reaction and sequence-specific oligonucleotide probe (SSOP) methods. RESULTS: We determined 5 single nucleotide polymorphisms at positions -1031 (T/C), -863 (C/A), -857 (C/T), -308 (G/A), and -238 (G/A) in the 5'-flanking region of the TNF-alpha gene. There were no significant differences in the genotype and allele frequency when we compared G-EOP patients to healthy subjects. Because the frequency of polymorphic alleles at positions -308 and -238 was very low in this study population, we demonstrated the existence of 4 detected haplotypes and 6 detected genotypes concerning 3 single nucleotide polymorphisms (-1031, -863, and -857). The frequency of the H1/H3 (TCC/TCT)-detected genotype tended to decrease in G-EOP patients compared to healthy subjects, but was not statistically significant. CONCLUSION: These findings suggest there is no significant association between polymorphisms in the 5'-flanking region of the TNF-alpha gene and susceptibility to G-EOP in Japanese patients.
A 55-year-old man was admitted to our hospital with fever and vomiting. Abdominal computed tomography (CT) revealed multiple low density masses in the liver. A diagnosis of primary adenosquamous carcinoma of the liver was confirmed by histological examination of a necropsy specimen. The present case showed leukocytosis and hypercalcemia with high levels of serum granulocyte-colony-stimulating factor (G-CSF) and parathyroid hormone related protein (PTHrP). Recent studies have shown that G-CSF and PTHrP are responsible for the paraneoplastic syndromes with leukocytosis and hypercalcemia. The tumor cells demonstrated positive cytoplasmic immunohistochemistry staining with anti-G-CSF and anti-PTHrP antibodies. This result suggested that the tumor produced G-CSF and PTHrP.
We report a case of lymphocutaneous sporotrichosis in a 69-year old man who had nodular-ulcerated lesions on the right hand and forearm. Small nodules remained on the right hand after 8 weeks of 0.5 g daily treatment with potassium iodide. Alternatively, terbinafine therapy (125 mg/day) resulted in healing with atrophic scars after 9 weeks without side effects. We reviewed 67 patients of cutaneous sporotrichosis in Japan from 1993 to 1999. Those cure rates (and mean durations of treatments in parentheses) are 90.9% (8.1 weeks) with potassium iodide, 86.6% (12.6 weeks) with itraconazole (100 mg/day) and 71.4% (12.8 weeks) with terbinafine (125 mg/day) treatments, respectively. These results lead us to consider a daily dose of 250 mg as more appropriate for terbinafine.
PURPOSE: To elucidate histopathologic features of the lacrimal gland in chronic graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation. METHODS: Lacrimal gland specimens from five patients who had dry eye as part of the symptoms of chronic GVHD were examined by immunohistochemistry and transmission electron microscopy. Lacrimal gland specimens from five patients with Sjögren's syndrome (SS) were used as control samples. RESULTS: Lymphocytes, predominantly T cells, were found primarily in the periductal areas of the lacrimal gland from patients with chronic GVHD, whereas B cells were the dominant infiltrating cells in the acinar areas of the lacrimal gland from patients with SS. Notable findings in the lacrimal gland from patients with chronic GVHD were marked fibrosis of the glandular interstitium and an increase in the number of CD34(+) stromal fibroblasts. These findings were more prominent in patients with severe dry eye than in those with mild dry eye. Electron microscopic observations of the lacrimal gland from patients with chronic GVHD revealed that stromal fibroblasts were attached to various inflammatory cells, especially T cells, through primitive or rudimentary contacts. In addition, the presence of a well-developed rough endoplasmic reticulum in the fibroblasts and newly synthesized collagen fibrils in the extracellular matrix indicated an active production of extracellular matrix components. Electron micrographs revealed multilayered and thickened basal laminae of blood vessels, ducts, and lobules in the lacrimal gland of patients with chronic GVHD; however, these observations were infrequently observed in the lacrimal glands of patients with SS. CONCLUSIONS: The results suggest substantial differences in the lacrimal gland histopathology of patients with chronic GVHD and SS. In addition, it is likely that stromal fibroblasts are actively involved in the pathogenic process of chronic GVHD in the lacrimal gland by producing excessive extracellular matrix components.
Lung cancer with a solitary metastasis to the stomach occurred in a 65-year-old man, surgically treated for gastric metastasis was followed by pulmonary resection. The gastric metastasis accompanied by upper gastrointestinal hemorrhage. After total gastrectomy to control this hemorrhage, a left lower lobectomy with a partial resection of the lingular segment and combined resection of the chest wall were done. Histopathological features of both the primary tumor in the left lower lobe and the gastric tumor were poorly differentiated adenocarcinoma, and showed the same immunoreactivities of p53 protein, carcinoembryonic antigen and keratin. These results indicate that the gastric tumor was a metastasis originated from the lung cancer.
In recent years, bone metabolic markers have been one of the most important tools in osteoporosis treatment because of their usefulness of understanding current bone metabolic status, early judgment of osteoporosis treatment and their possibilities in the evaluation of fracture risk. It is important that we utilize bone metabolic markers for osteoporosis treatment in combination with the measurement of bone mineral density and the evaluation of fractures by X-ray photograph.
Glutamine:fructose-6-phosphate amidotransferase (GFAT) is the first and rate-limiting enzyme of the hexosamine biosynthesis pathway, which plays an important role in glucose toxicity and cellular insulin resistance. Thus, the mechanisms by which GFAT expression is regulated under physiological and pathological conditions are of interest in connection with diabetes. In this study, we cloned the 5'-flanking region of the mouse GFAT2 gene and characterized its promoter activity. Sequence analysis revealed several putative regulatory elements Sp1, a CCAAT box, AP-1 and AP-2, but no TATA box. Transfection experiments showed that the 5'-flanking region between -2462 to +38 relative to the transcription start site of the GFAT2 gene drives transcription in NIH3T3 cells and that the fragment from -141 to -9 has the highest transcription activity. Reporter assays using deletion and mutant variants suggested that the Sp1 sites at positions -83 to -78 and -22 to -17 both play an important role in the basal promoter activity of the mouse GFAT2 gene. Electrophoretic mobility shift assay showed DNA-protein binding at both Sp1 sites. We also compared the promoter activities of mouse GFAT1 and GFAT2 in several cell lines.
Postprandial hyperlipidemia is frequently accompanied with intra-abdominal visceral accumulation in human subjects. We have found that the decreased lipoprotein lipase (LPL) mass and activity is negatively associated with the amount of visceral fat accumulation. Here, we studied the postprandial hyperlipidemia using the OLETF rat, a model with visceral obesity, in order to clarify the molecular mechanism causing postprandial hyperlipidemia accompanied with visceral obesity. At the same age of 32 weeks, the OLETF rats showed obviously higher plasma leptin, total cholesterol, triglyceride, and HDL-cholesterol levels than the control LETO rats, although the plasma glucose level was not significantly different. Fat-loading test revealed the delayed metabolism of exogenous fat in the OLETF rats compared to the LETO rats, similar to human subjects with visceral obesity. In the obese rats, plasma levels of LPL mass and activities were 60 and 49% of control rats. The expression of LPL gene was decreased in subcutaneous adipose tissues and skeletal muscle of OLETF rats to 40 and 52% compared to those of LETO rats. In OLETF rats, plasma tumor necrosis factor-alpha (TNF-alpha) and insulin levels were increased to 2.0- and 2.3-folds compared to those in control rats. Furthermore, plasma insulin and TNF-alpha levels in OLETF rats were negatively correlated with the expression levels of LPL gene in subcutaneous fat and muscle. These results indicate that decreased LPL mass and activity in the animal model with visceral obesity is possibly caused by decreased expression of LPL gene in tissues mediated by the increased levels of insulin and TNF-alpha. The different expression of LPL gene in tissues associated with the increased levels of insulin and TNF-alpha possibly elucidate the underlying mechanisms involving the postprandial hyperlipidemia observed in visceral obesity.
Mutations of the von Hippel-Lindau (VHL) tumor suppressor gene predispose individuals to a variety of human tumors, including renal cell carcinoma, hemangioblastoma of the central nervous system, and pheochromocytoma. Here we report on the identification and characterization of the Drosophila homolog of VHL. The predicted amino acid sequence of Drosophila VHL protein shows 29% identity and 44% similarity to that of human VHL protein. Biochemical studies have shown that Drosophila VHL protein binds to Elongins B and C directly, and via this Elongin BC complex, associates with Cul-2 and Rbx1. Like human VHL, Drosophila VHL complex containing Cul-2, Rbx1, Elongins B and C, exhibits E3 ubiquitin ligase activity. In addition, we provide evidence that hypoxia-inducible factor (HIF)-1alpha is the ubiquitination target of both human and Drosophila VHL complexes.
The several linked polymorphic genes of the MHC, which has been proposed as a prime determinant of sensed genetic individuality within species, is known to operate in mice by olfactory recognition in aspects of reproductive behavior that concern mate selection, thereby favoring outbreeding and heterozygosity, and also concern the maintenance of pregnancy. A single base-change can alter an individual MHC odortype, and the potential range of combinatorial MHC-determined odortypes is clearly vast. Following our findings that newborn mice already express their MHC odortype (which is detectable at 9 days of gestational age), we sought to determine whether MHC is involved in behavioral aspects of early development, such as rearing. In the studies presented herein, we report the ability and proclivity of mothers to recognize and preferentially retrieve syngeneic (genetically identical) pups from other pups differing only for MHC. Reciprocally, we report the ability of pups to recognize their familial environment, regardless of whether they had been nursed by their biological mothers or by foster mothers. Early learning experiences of the MHC environment are apparently a key element in survival, assuring maternal protection and promoting outbreeding.
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An autosomal recessive neurological mutant, ataxia (ax) mouse, was investigated to determine whether neuronal cell death occurs in the brain. The brains of homozygotes (ax(J)/ax(J)) and phenotypically normal littermates (ax(J)/+ or +/+) aged at 23-38 days were examined by the terminal dUTP nick-end-labeling (TUNEL) method. A few TUNEL-positive cells were observed in the granule cell layer of the cerebellum, the dentate gyrus, and the olfactory bulb of normal mice. In the affected mice, the number of TUNEL-positive cells was significantly increased in the cerebellum, particularly in the granule cell layer, compared to normal littermates. The findings suggest that ax mice will be useful as a model for studies on the genetic basis of apoptotic neuronal cell death.
Acute phase responses to intragastric administration of a single dose of CCl(4) were examined with albumin mRNA turnover as a marker. Based on the combination of the changes in stability of albumin mRNA and activity of transcription of its gene, the entire course of liver injury was classified into three stages, the first stage for aggravation of injury until 9 h, the second from 9 to 24 h, and the third for repair of injury or regeneration of liver after 48 h. Liver S100 fractions from normal and CCl(4)-treated rats contained, in total, 11 polypeptides cross-linked with part of albumin mRNA, although they did not appear to be specific to this mRNA. Their profiles were altered together with the changes in stability of albumin mRNA in different stages. These findings suggest that the polypeptides with distinct properties play roles in physiologically significant processes involved in utilization and turnover of albumin mRNA, apparently altering its stability.