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Biomedical subjects

Y Shibasaki

Publications and source records attributed to Y Shibasaki.

At least 145 records · Page 8Linked to original sources
PubMed1985

Restriction fragment length polymorphism of the insulin gene region in Japanese diabetic and non-diabetic subjects.

A polymorphic locus flanking the 5' end of the insulin gene was studied in 154 unrelated Japanese diabetic and nondiabetic subjects. A predominance of the small allele was found with the following frequency: of 64 nondiabetic subjects, only 3 of 128 alleles were of the large class (2%); none of 78 alleles were of the large class in 39 Type 1 (insulin-dependent) diabetic subjects, and 4 of 102 alleles (4%) were of the large class in 51 Type 2 (non-insulin-dependent) diabetic subjects. The very low frequency of large allele may relate to the lower prevalence of atherosclerosis in Japanese. However, this possibility requires further examination.

Alleles↗
PubMed1985

Posttranslational cleavage of proinsulin is blocked by a point mutation in familial hyperproinsulinemia.

Familial hyperproinsulinemia is characterized by the accumulation of proinsulin-like material (PLM) in the plasma of affected patients. This disorder is inherited in an autosomal dominant fashion. The accumulation of PLM is thought to be due to the impaired conversion of proinsulin to insulin. Although PLM has been suggested to have an amino acid substitution, it has been impossible to locate and identify a substituted amino acid, due to the difficulty in isolating sufficient amounts of PLM from plasma samples. Therefore, we analyzed leukocyte DNA from one member of a proinsulinemic family, and we found a point mutation that changed guanine to adenine in the insulin gene. This transition implies that a substitution of histidine for arginine has occurred at amino acid position 65. Furthermore, it indicates that arginine at 65 is essential for the conversion of proinsulin to insulin. Our results suggest a novel mechanism by which disease can be incurred: a heritable disorder can result from a posttranslational processing abnormality caused by a point mutation.

Amino Acid Sequence↗
PubMed1984

Clinical application of prostaglandin E1 (PGE1) upon orthodontic tooth movement.

Chemically produced prostaglandin E1 (PGE1) was administered in clinical cases of orthodontic tooth movement. In the first phase, lingual arch springs were applied on both sides of the maxilla to upper first premolars which were scheduled for extraction. One side received submucosal injections of PGE1 and the other received vehicle injections. The rate of tooth movement in the buccal direction approximately doubled on the side of several PGE1 injections as compared to the control side. In the second phase, the PGE1 injections were applied in canine-retraction cases for up to 3 weeks in first-premolar-extraction cases. The rate of distal canine movement was almost double on the side receiving PGE1 injections as compared to the vehicle-injected side. In the third phase, the PGE1 injections were applied on routine canine retraction in first-premolar-extraction cases. The rate of distal canine movement was almost 1.6-fold on the side of PGE1 injections as compared to the vehicle-injected side. Throughout this study, no side effects were observed macroscopically in the gingiva and roentgenographically in the alveolar bone, except for a slight pain reaction consistent with orthodontic tooth movement.

Alprostadil↗
PubMed1984

Alteration of beta-cell function in different diabetic states.

To assess the effects of metabolic control upon beta cell function in diabetes, pro-insulin and insulin were determined following gel-filtration of plasma at two time points in each three diabetic patients, once when the metabolic state was severely deranged and again after the metabolic state had improved after therapy. Before therapy, proinsulin concentration were 30 pM (as IRI), both fasting and at 2 hours after an oral glucose load. These values did not change with treatment. Insulin concentrations were 22 pM at both time points before therapy. With treatment, plasma insulin increased 2-fold at fasting and 7-fold at 2 hours after oral glucose. These results suggest an exhaustion of the insulin pool in beta cells during severe metabolic decompensation of diabetes, a condition which may be reversed by correction of the metabolic states of the patients with proper therapy.

Acromegaly↗
PubMed1984

[Pharmacological studies on new cephamycin, MT-141. (1) Its effect on central nervous system, respiration and cardiovascular system].

The results on pharmacological effects of MT-141 were as follows. MT-141 did not exert effect on central nervous system in mice and rabbits but potentiated the anesthetic effect of thiopental at doses above 800 mg/kg i.v. MT-141 slightly raised a level of blood pressure in dogs and also caused a slight increase in the blood flow and heart rate when intravenously given more than 400 mg/kg. This compound did not affect the spontaneous contraction of isolated guinea pig atria and the blood vessels in perfused rabbit ears. MT-141 did not significantly affect the spontaneous contraction and coronary flow in isolated hearts of guinea pig. The body temperature was raised slightly by an injection of more than 400 mg/kg of MT-141. These results suggest that MT-141 does not possess specific effect on central nervous system but at a high dose slightly affects the autonomic nervous system such as blood pressure, body temperature, heart rate and blood flow in experimental animals.

Animals↗
PubMed1982

Chromosomal investigations of the Usubuchi sarcoma. II. Chromosomal alteration of the stem line cells revealed by differential staining techniques.

Stem line cells of the Usubuchi sarcoma (US) were karyologically investigated by means of G-, C-, and N-banding methods in ten samples from the 1,923rd to 2,081st transfer generations, with special attention to the structural alteration of marker-1 chromosome. The US cells showed wide variations in chromosome constitution and number, while the modal number of chromosomes was consistently 64 in all the generations examined. The chromosome constitutions varied widely even in cells with the modal number. In the early stage (1,923rd to 1,936th generations) the US contained two major stem lines characterized by marker combinations such as 1-2-3-4(1)-4(3)-8 and 2-3-4(1)-4(2)-4(3)-8, occurring with nearly similar frequency. From the middle to later transfer stages (from the 2,004th to the 2,081st generations), the 1-2-3-4(1)-4(3)-8 stem line rapidly declined and finally disappeared. In contrast, the 2-3-4(1)-4(2)-4(3)-8 line became a predominant part of the stem line. The G- and C-banding and population analyses of the stem line cells strongly suggested that marker 4(2) might have been derived from marker 1 by a deletion of the distal half of its long arm. The US studied contained a few stem lines and various types of sublines, each karyologically characteristic. G-Banding analysis revealed various types of intra- and interchromosomal rearrangements probably due to occasional chromosomal mutations either in markers or in nonmarkers in both stem lines and sublines. It seems likely that the stem line cells of the US are not always stable, but rather variable, in their chromosome makeup during the course of multiplication and successive transfers.

Animals↗
PubMed1982

Behavior of mast cells in periodontal ligament associated with experimental tooth movement in rats.

Orthodontic mechanical stress reduced the frequency of the appearance of mast cells stainable with toluidine blue in the periodontal ligament on both the pressure and tension sides of rat molar teeth. This effect was seen immediately after insertion of elastic bands between the first and second molars, and the greatest reduction in the number of mast cells stainable with toluidine blue was observed 15 min after insertion.

Animals↗