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Yuji Tanaka

Publications and source records attributed to Yuji Tanaka.

77 records · Page 5Linked to original sources
PubMed2002

A family of autosomal dominant hypocalcemia with a positive correlation between serum calcium and magnesium: identification of a novel gain of function mutation (Ser(820)Phe) in the calcium-sensing receptor.

To date about 20 activating mutations in the calcium-sensing receptor (CaR) gene have been identified to cause autosomal dominant hypocalcemia (ADH) or sporadic hypoparathyroidism. We report a novel activating mutation in the CaR gene in a Japanese family with ADH. The proband, a 15-yr-old boy, and 5 other patients in 3 generations were asymptomatic, except for the proband's grandmother who had a history of seizures. They showed mild hypocalcemia (1.68-1.98 mmol/liter) with normal urinary calcium excretion and low normal serum PTH levels. Their serum magnesium concentrations were below normal in 3 adults and within the normal range in 3 teenagers. There was a significant positive correlation (r = 0.90; P < 0.05) between the serum calcium and magnesium concentrations of 6 affected members. Nucleotide sequencing revealed that the proband had a known polymorphism (Gly(990)Arg) and a novel heterozygous mutation substituting phenylalanine for serine at codon 820 (Ser(820)Phe) in the sixth transmembrane helix of the CaR. In other family members, the Ser(820)Phe mutation cosegregated with hypocalcemia. The mutation was not detected in 50 control subjects. The Gly(990)Arg polymorphism was observed in 8 of 9 family members with or without hypocalcemia and in 36 of 50 controls. The sensitivity of the Ser(820)Phe mutant CaR to calcium was assessed using transiently transfected HEK293 cells and measuring the increases in intracellular Ca(2+) concentrations in response to the changes in extracellular Ca(2+). The concentration-response curve of the mutant receptor was left-shifted, and its EC(50) (2.5 mM) was significantly (P < 0.05) lower than that of the wild-type CaR (3.3 mM). We conclude that the Ser(820)Phe mutation in the CaR caused ADH in this family. The positive correlation between serum calcium and magnesium levels observed in this family may support the concept that renal CaR acts as a magnesium sensor as well as a calcium sensor.

Adolescent↗
PubMed2002

[Dysphagia due to giant cervical osteophytes].

We reported a patient with isolated dysphagia due to an esophageal canal stenosis compressed by focal cervical spondylotic osteophytes. The patient was a 63-year-old male who developed swallowing disturbance of predominantly solid materials. The neurological examination showed subjectively isolated dysphagia unassociated with any significant cranial nerve signs. Cervical magnetic resonance imaging and X-ray demonstrated giant cervical spurs focally at the ventral portion of the C 5/6 vertebral bodies, protruding ventrally and compressing mildly to the esophageal canal. The intervertebral disc formation was relatively preserved between the osteophytes. At the neck flexion portion, the esophagus was severely compressed between the osteophytes and the epiglottis. Videofluoroscopic examination of swallowing function showed a congestion of the contrast medium at the portion of the epiglottic vallecula, unassociated with aspiration into the trachea. The endoscopic examination showed erosion of the posterior wall of the esophagus at the portion compressed by the osteophytes. The anti-inflammatory medication improved the symptom of dysphagia, and the patient has been carefully followed-up without a surgical procedure. The presence of giant osteophyte should be considered in the differential diagnosis of subjectively isolated dysphagia unassociated with any significant cranial nerve signs.

Cervical Vertebrae↗
PubMed2001

Immunocytochemical localization of synphilin-1, an alpha-synuclein-associated protein, in neurodegenerative disorders.

Alpha-synuclein is a major component of Lewy bodies (LB) in Parkinson's disease (PD) and dementia with LB (DLB), as well as of glial cytoplasmic inclusions (GCI) in multiple system atrophy (MSA). Recently, a novel protein called synphilin-1 has been identified that associates with alpha-synuclein, and it has been reported that co-transfection of both alpha-synuclein and synphilin-1 in mammalian cells yielded eosinophilic cytoplasmic inclusions resembling LB. Immunocytochemical and ultrastructural investigations have now been performed on the brain of patients with various neurodegenerative disorders using anti-synphilin-1 antibodies. These antibodies immunostained the neuropil in a punctate pattern throughout the brain of control subjects. In PD, most LB observed in the brain stem were positive for synphilin-1. These LB showed intense staining in their central cores, but their peripheral portions were only weakly stained or unstained. Pale bodies and Lewy neurites, which were positive for alpha-synuclein, were synphilin-1 negative. In DLB, a small fraction of cortical LB were immunolabeled by anti-synphilin-1. In MSA, numerous GCI were positive for synphilin-1. Immunoelectron microscopy revealed that the reaction product was localized within filamentous and circular structures in LB. Various neuronal and glial inclusions in neurodegenerative disorders other than LB disease and MSA were synphilin-1 negative. These findings suggest that abnormal accumulation of synphilin-1 is specific for brain lesions in which alpha-synuclein is a major component.

Brain↗
PubMedDate not supplied

Dietary iron restriction improves aminotransferase levels in chronic hepatitis C patients.

BACKGROUND/AIMS: It is generally accepted that iron overload plays an important role in the pathogenesis of liver cell injury in chronic hepatitis C. The present study was undertaken to evaluate whether low-iron diet improves liver function tests in patients with chronic hepatitis C. METHODOLOGY: Seventeen patients with chronic hepatitis C (13 men and 4 women, 54 +/- 14 years old) that did not respond to, or were unsuitable for interferon therapy, were enrolled in this study. All patients had been pretreated with ursodeoxycholic acid for more than 12 months before the beginning of the study. Dietary iron intake was restricted to less than 7 mg/day, and the patients were followed up for 18 months. RESULTS: Mean daily iron intakes, calculated from food records, were 5.9 and 6.4 mg after 6 and 12 months, respectively. The mean serum ferritin decreased significantly from 362 ng/mL at entry to 179 ng/mL after 18 months. The serum unsaturated iron binding capacity level increased significantly from 163 micrograms/dL at entry to 203 micrograms/dL after 18 months. The serum aspartate aminotransferase decreased significantly from 62 IU/L at entry to 47 IU/L after 18 months, and serum alanine aminotransferase from 68 IU/L at entry to 53 IU/L after 18 months. Serum iron, hepatitis C virus-RNA titer and platelet count remained unchanged throughout the study. CONCLUSIONS: These results suggest that iron-restricted diet may be an important therapeutic modality for improving liver injury in patients with chronic hepatitis C.

Adult↗