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Biomedical subjects

I Shimada

Publications and source records attributed to I Shimada.

At least 145 records · Page 8Linked to original sources
PubMed1986

A case of normocalcemic primary hyperparathyroidism with osteomalacia.

A 59 year-old patient had lumbago and pain in hip joints, knees, and ribs of long duration. Severe hypophosphatemia and high serum ionized calcium were found in spite of normal level of total serum calcium. The serum parathyroid hormone and alkaline phosphatase levels were elevated, and diffuse demineralization of the bones and renal stones were found by x-ray examination. Parathyroid adenoma was diagnosed from the subtraction image of the 99mTc O-4 and 201Tl-Cl2 scintigrams. Osteomalacia was demonstrated by bone biopsy at the right iliac crest. A right lower parathyroid adenoma of 2.0 X 1.8 cm, weighing 4.0 g was removed. The long standing phosphate depletion and hypophosphatemia, due to hyperparathyroidism causing renal damage with nephrocalcinosis and reduced synthesis of active vitamin D, and milk tolerance due to gastroduodenostomy were probably responsible for producing the clinical picture of normocalcemic hyperparathyroidism complicated with osteomalacia.

Adenoma↗
PubMed1985

Binding modes of inhibitors to ribonuclease T1 as studied by nuclear magnetic resonance.

The binding modes of inhibitors to ribonuclease T1 (RNase T1) were studied by the analyses of 270-MHz proton NMR spectra. The chemical shift changes upon binding of phosphate, guanosine, 2'-GMP, 3'-GMP, 5'-GMP, and guanosine 3',5'-bis(phosphate) were observed as high field shifted methyl proton resonances of RNase T1. One methyl resonance was shifted upon binding of phosphate and guanosine nucleotides but not upon binding of guanosine. Four other methyl resonances were shifted upon binding of guanosine and guanosine nucleotides but not upon binding of phosphate. From the analyses of nuclear Overhauser effects for the pair of H8 and H1' protons, together with the vicinal coupling constants for the pair of H1' and H2' protons, the conformation of the guanosine moiety as bound to RNase T1 is found to be C3'-endo-syn for 2'-GMP and 3'-GMP and C3'-endo-anti for 5'-GMP and guanosine 3',5'-bis(phosphate). These observations suggest that RNase T1 probably has specific binding sites for the guanine base and 3'-phosphate group (P1 site) but not for the 5'-phosphate group (PO site) or the ribose ring. The weak binding of guanosine 3',5'-bis(phosphate) and 5'-GMP to RNase T1 is achieved by taking the anti form about the glycosyl bond. The productive binding to RNase T1 probably requires the syn form of the guanosine moiety of RNA substrates.

Endoribonucleases↗
PubMed1985

Taste response to 2,5-anhydro-D-hexitols; rigid stereospecificity of the furanose site in the sugar receptor of the flesh fly.

2,5-Anhydro-D-mannitol with a fixed furanose ring stimulated the sugar receptor of the flesh fly and reacted with the furanose site. This is the first direct evidence that a furanose can stimulate the sugar receptor and supports strongly the assumption that beta-D-fructofuranose is the only stimulatory component in the solution of D-fructose. Rigid stereospecificity of the furanose site in the sugar receptor is discussed according to the effectiveness of various synthetic 2,5-anhydro-D-hexitols and related compounds. At least four receptor sites are concluded to be in a single sugar receptor: a pyranose (P) site, a furanose (F) site, an aliphatic carboxylate (R) site and an aromatic amino acid (Ar) site.

Animals↗
PubMed1985

Ventricular arrhythmias late after aortic and/or mitral valve replacement.

Since it is not yet known whether ventricular arrhythmias in patients with valve replacement are associated with an increased risk of sudden death, as in patients with coronary artery disease, a total of 46 patients who were long-term survivors of aortic and/or mitral valve replacement were examined with 24-hour ambulatory electrocardiographic monitoring, and the factors influencing the occurrence of ventricular arrhythmias were analyzed. The significance of ventricular arrhythmias in the prognosis of valve replacement is discussed. The occurrence of ventricular arrhythmias was significantly higher: 1) in patients with aortic stenosis than in those with aortic regurgitation, 2) in patients with multiple valve surgery than in those with single valve replacement and 3) in patients with larger heart size. Pre- and postoperative hemodynamics, including left ventricular function, were not significantly related to the incidence of ventricular arrhythmias. A review of the patients who died suddenly, late after valve replacement suggests that frequent ventricular arrhythmias and thromboembolism are the most important factors in the late mortality of these patients. The prognostic significance of postoperative ventricular arrhythmias in patients with valve replacement requires additional study.

Adolescent↗
PubMed1985

Modified Blalock-Taussig shunt following long-term administration of prostaglandin E1 for ductus-dependent neonates with cyanotic congenital heart disease.

In the treatment of cyanotic heart diseases in neonates who are ductus dependent, the small size of the pulmonary artery and/or subclavian artery often precludes construction of a sufficient Blalock-Taussig shunt. To avoid an emergency operation and to obtain pulmonary and subclavian arteries of adequate size (3 mm), a low dose of prostaglandin E1 was given to 16 neonates for a mean of 47 days (range 26 to 65 days), and a modified Blalock-Taussig shunt operation was performed in neonates whose mean age was 50 days. The pulmonary artery grew significantly (mean 4.5 mm) and the mean diameter of the subclavian artery was 3 mm, which was large enough for a good shunt at the time of operation. There were two late deaths and one operative death. All surviving patients shunts at the mean follow-up period of 22 months. The shunt was constructed on the same side as the ductus arteriosus so that the ductus could be ligated at the same operation in selected cases; the ductus may not close after discontinuation of prostaglandin E1 infusion and may cause uncontrollable congestive heart failure because of excessive pulmonary blood flow, particularly in patients with a univentricular heart. The ductus, dissected in nine patients, was enlarged and elongated in all and was ligated in four patients without complication.

Ductus Arteriosus, Patent↗