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Biomedical subjects

M Hirano

Publications and source records attributed to M Hirano.

At least 505 records · Page 28Linked to original sources
PubMed1989

Dual loading of the fluorescent indicator fura-2 and 2,7-biscarboxyethyl-5(6)-carboxyfluorescein (BCECF) in isolated myocytes.

Isolated rat heart myocytes were loaded with both the Ca2+ sensitive fluorescent probe fura-2/AM and the fluorescent pH indicator 2,7-biscarboxyethyl-5(6)-carboxyfluorescein (BCECF/AM). Changes in [Ca2+]i and pHi were measured simultaneously using digitized video fluorescence microscopy. In measurement of [Ca2+]i and pHi, the ratios of dual-loaded cells were not different from single-loaded cells. Using this method, [Ca2+]i and pHi in myocytes were 48 +/- 7 nM and 7.17 +/- 0.05. It is concluded that [Ca2+]i and pHi could be measured simultaneously in isolated myocyte using dual-loading of fura-2 and BCECF.

Animals↗
PubMed1989

Class switch from mu to delta is mediated by homologous recombination between sigma mu and sigma mu sequences in human immunoglobulin gene loci.

Class switch of immunoglobulin from mu to gamma occurs by recombination between two repetitive switch sequences: S mu and S gamma. However, there are no such sequences in the mu-delta introns of human and mouse genomes. Although the frequency of IgD-secreting cells is extremely low in mouse about 1% of patients with myeloma produce IgD in human. In a previous report (Nucleic Acids Res. 1988. 16: 9497) we reported that a 442-bp DNA sequence located in the JH-mu intron (defined as sigma mu) was inserted into the mu-delta intron (defined as sigma mu) in human genome. There is no such insertion in mouse. We analyzed Ig H chain gene loci of two human IgD myelomas: one was analyzed by cloning and sequencing and the other by Southern hybridization. We found that recombination had occurred between these two homologous DNA sequences, resulting in loss of the DNA segment from sigma mu to sigma mu. On the other hand, in a Burkitt lymphoma, Daudi, the DNA fragment from sigma mu to sigma mu was duplicated. These results suggest that homologous recombination between sigma mu and sigma mu sequences mediates class switch from mu to delta in human and that it occurs via unequal crossing-over between sister chromatids or daughter chromosomes.

Amino Acid Sequence↗
PubMed1989

Involvement of brain stem noradrenergic neurons in the development of hypertension in spontaneously hypertensive rats.

This study attempted to investigate the possible involvement of the brain stem noradrenergic system in the development of hypertension in spontaneously hypertensive rats. Steady-state norepinephrine, dopamine, serotonin and 5-hydroxyindoleacetic acid concentrations and norepinephrine turnover were determined in the individual brain stem nuclei using high performance liquid chromatography with electrochemical detection. Decreased norepinephrine contents in the nucleus tractus solitarii in spontaneously hypertensive rats compared with Wistar-Kyoto rats at the age of 4, 8, and 16 weeks were demonstrated. In later stages (8 and 16 weeks), increased norepinephrine levels were observed in the nucleus reticularis gigantocellularis, the A1 and A5 areas. Norepinephrine turnover was not different between spontaneously hypertensive rats and Wistar-Kyoto rats in the nucleus tractus solitarii at the age of 4 and 16 weeks and increased in the nucleus reticularis gigantocellularis of spontaneously hypertensive rats at 16 weeks. Our results indicate that altered norepinephrine metabolism in the specific brain stem nuclei, especially the consistently decreased norepinephrine in the nucleus tractus solitarii of spontaneously hypertensive rats, contribute to the development of genetic hypertension.

Adrenergic Fibers↗
PubMed1989

A case of metastasis from gastric cancer to the thyroid gland.

Metastatic tumors in the thyroid gland are rarely seen in clinical practice. This report describes a case of metastasis from gastric cancer to the thyroid, found five years after removal of the primary gastric lesion. The patient had a large thyroid mass extending to the mediastinum, but there were no obvious metastatic lesions anywhere except in the thyroid. Subtotal thyroidectomy was performed and histological examination revealed the same findings a those of the original gastric cancer. Of additional interest are the findings that led us to believe this metastatic tumor produced alpha-fetoprotein. Seven months following the operation, the patient dies suddenly and, although it is difficult to say whether the patient's survival was prolonged, we believe that the thyroid surgery gene him considerable palliation.

Adenocarcinoma↗
PubMed1989

T-cell malignancy following B-cell lymphoma in remission.

A T-cell malignancy developed in a 64-year-old man with recurrent B-cell lymphoma after one and a half years of remission. Immunophenotypic and DNA analyses confirmed clonality and cell lineage of both lymphoid malignancies. Sequential development of B- and T-cell malignancies in this patient may be an example of biclonal lymphoma or treatment-related secondary lymphoma. However, another possibility would be the existence of a transformed lymphoid stem cell that underwent intraclonal conversion from B- to T-cell lines.

Antibodies, Viral↗
PubMed1989

The significance of breast milk biotinidase.

Biotinidase (EC 3.5.1.12) activity in human breast milk was first demonstrated by us, using a newly developed method. The enzyme activity was relatively low compared with that in human serum. However, its activity increased significantly with thiol-reactive agents. Taurine and glutathione also enhanced the enzyme activity considerably. From these results, we speculate that biotinidase in milk would be protected from various inactivation-mechanisms in the same manner as milk lipase. Biotinidase might play an important role in the intestinal absorption of the indispensable vitamin, biotin, during infancy, when enzymes in the pancreatic juice are still immature.

Amidohydrolases↗
PubMed1989

In vitro and in vivo evaluations of a new broad-spectrum oral cephalosporin, BMY-28232, and its prodrug esters.

The in vitro activity of a new cephalosporin, BMY-28232 (7-[(Z)-2-(2-aminothiazol-4-yl)-2-hydroxyiminoacetamido]-3-[ (Z)-1- propenyl]-3-cephem-4-carboxylic acid), was compared with those of cefuroxime and BMY-28488, the 3-vinyl congener of BMY-28232, against 899 bacteria including strains resistant to newer cephalosporins. BMY-28232 displayed potent, broad-spectrum antibacterial activity with high stability to various types of beta-lactamase. Its acetoxyethyl ester (BMY-28271) and pivaloyloxymethyl ester (BMY-28257) were well absorbed after oral administration to mice and rats. Both esters were metabolized to BMY-28232 and mainly excreted in urine. Oral bioavailability of both prodrug esters (60 to 70%) was better than that of cefuroxime axetil (46%) and gave excellent therapeutic efficacy against gram-positive- and gram-negative-bacterial infections in mice. Oral 50% protective doses (in milligrams per kilogram of body weight) of 0.65 and 0.72 for Staphylococcus aureus Smith, 0.9 and 1.2 for Escherichia coli Juhl, 1.6 and 1.6 for Proteus vulgaris, and 18.9 and 14.3 for Enterobacter cloacae were obtained for BMY-28271 and BMY-28257, respectively.

Animals↗
PubMed1989

Asymmetry of the laryngeal framework: a morphologic study of cadaver larynges.

Asymmetry of the laryngeal framework was investigated with 50 excised human larynges, ten from newborns (five males, five females), 20 from adults in their 20s (ten males, ten females), and 20 from adults in their 50s (ten males, ten females). All adults were right-handed. The results are summarized as follows. 1) The laryngeal framework was asymmetric to a greater or lesser extent in all larynges. 2) The degree of asymmetry did not differ among different age groups or between sexes. 3) In newborns, there was no directional preponderance in asymmetry. 4) In older adults, there was a directional preponderance in asymmetry. The right thyroid lamina tended to tilt laterally whereas the left lamina showed a tendency to tilt medially. The right cricoarytenoid joint tended to be located slightly more laterally, posteriorly, and inferiorly than the left joint. The longitudinal axis of the thyroid cartilage was inclined to shift to the right posteriorly against the axis of the cricoid cartilage. The thyroid cartilage as a whole tended to tilt to the right against the cricoid cartilage. 5) There must be some compensatory mechanisms for the asymmetric framework to keep the vocal fold edges relatively symmetric.

Adult↗
PubMed1989

Hydroxylapatite for laryngotracheal framework reconstruction.

Hydroxylapatite plates and rings were employed for reconstruction of the laryngotracheal framework in 12 patients. The cause of the framework defect was surgery for stenosis in nine cases and removal of malignancy in the other three. The trough method associated with a two-stage procedure was tolerated in all 12 cases. Hydroxylapatite plates or rings were used to reconstruct the framework during the second stage. The implant was well taken in all cases, without any infection or rejection. Nine of the 12 cases resulted in excellent airways.

Adult↗
PubMed1989

Improved surgical technique for epidermoid cysts of the vocal fold.

An improved surgical technique for epidermoid cysts of the vocal fold is presented. This technique employs a specially designed double-bladed elevator. Following betamethasone injection around the cyst, an incision is made posterior to the cyst at its mediolateral midpoint. The incision is extended anteriorly over the cyst with the use of a double-bladed elevator. The cyst then is elevated carefully from the surrounding tissue and removed. A single incision line on the upper aspect of the vocal fold should be the result. Eight patients were operated on with the present technique. The voice was improved postoperatively in all patients. The voice improvement was reflected objectively in stroboscopic findings, maximum phonation time, airflow rate, fundamental frequency and intensity of phonation, and results of acoustic analyses of voice.

Adult↗
PubMed1989

[Application of Holter electrocardiography to exercise testing for the group examination of school children: comparison between obese and normal children].

Application of Holter electrocardiography to an exercise test for heart function is useful in the group examination of school children. The circulatory responses to a step test among obese boys and girls and control were as follows: 1. Four cases of arrhythmia were detected, of whom 2 cases were discovered during exercise. ST-segment depression of 0.1 mV or more during and after exercise was recognized in 29 cases, 27 of the junctional- and 2 of the sagging slope, with a higher percentage in obese girls than in normal girls. 2. Serial ECG records during the procedure, performed for all children with the same single-step test, showed differences in the circulatory responses among the test groups. The load was estimated to be 76-86% of the maximal heart rate predicted by Cummings, with obese and girl groups being higher than other groups. The comparison revealed that the heart rate (HR) responses to exercise done by the boys increased faster than those by the girls at 1 minute after exercise. There were differences between obese and control and between boys and girls in HR at recovery, and also in HR before and 4 minutes after exercise between two sexes, which findings agree with other reports. 3. Concerning anthropometric factors, either the skinfold thickness or the obesity index was related to the HR at the peak of the exercise as well as immediately after it and to the half time. By contrast, the arm muscle diameter was found unrelated to the HR. Using this method, applied these combination of Holter ECG and step test to a group examination, we got ECG data for 254 subjects, 97.5% of which were suitable for analysis. We found this method to be effective for detecting ECG changes and for determining HR responses to exercise. This method is safe, simple, and inexpensive and is applicable to examination not only for school children but also for different population groups, for the estimation of circulatory responses.

Age Factors↗
PubMed1989

Multiplicity of spontaneous lung tumors in CD-1 mice.

The multiplicity of the spontaneous lung tumor in CD-1 mice was investigated in 413 males from 6 different control groups of 2-year carcinogenicity studies with agrochemicals. Among a total of 152 lung tumor bearers, 95 (62.5%) were seen with 1 nodule, 36 (23.7%) with 2 nodules, and 14 (9.2%) with 3 nodules. Three males bore 4 nodules and each of 5, 7, 9 and 10 nodules was seen in one male, respectively. In one control group 20 out of 30 lung tumor bearers had 2 or more nodules presenting a significant heterogeneity among the control groups in terms of the multiplicity of lung tumor nodule.

Animals↗
PubMed1989

[Bonding durability of various adhesion systems of dental alloy in aciditic solution].

Previous studies found that the adhesive resin provided strong adhesion to alloys. Also, the bond durability was improved by oxidation of alloys. In oral, many aciditic substances exist. However, the oxides yielded by oxidation are unstable in aciditic environment. Thereupon, the adhesive resin systems should be studied in aciditic environment. In this study, half of the alloy disks were air-brushed with alumina and the remaining half were polished with #600 emery. They were then ion-coated. One third of the disks were with Cu oxide another one third were Cu.Sn oxide, and remaining were Sn oxide. The handle was affixed by the 4-META resin. For reference, Co-Cr specimen oxidized ultrasonically was fabricated. Completed specimens emery polished were stored in lactic acid at 37 degrees C for 3 months, and sand-blasted were for 6 months. Then the tensile strength was measured. In 0.002% solution, initial bond strength of all the specimens was maintained after immersion. After 1.0% immersion, bond strength of Cu oxide coating specimen polished with emery decreased rapidly. Bond strength of Cu.Sn oxide and Sn oxide coated specimens decreased slowly. Sand-blasted specimens showed higher durability than emery polished. Co-Cr alloy specimen showed the highest durability, and 260 kgf/cm2 was maintained after 6 months in 2.0%.

Dental Alloys↗
PubMed1989

[Study on ion-coating surface treatment of dental alloys for adhesion. 2. Effect of Sn and Cu-Sn target on Au-Ag-Pd alloy].

Previous study found that ion coating treatment with Cu target demanded 10 minutes of treatment to achieve the durable adhesion with 4-META resin. For clinical application, it's indispensable to shorten the treatment period. Sn and Cu-Sn target were examined in this study. 4 minutes of treatment with Sn target showed high bond strength of adhesion. However, the excess of treatment time over 8 minutes caused the remarkable decrease of adhesion durability against thermal cycling. In clinical situation, many of the prosthesis possess the wings of complex shape and it's difficult to attain the uniform coating by only once treatment. However, the repetition of treatment with Sn target is undesirable because of the decrease of adhesion durability. Favorable result was shown by 4 minutes of treatment with Cu-Sn target and even by 30 minutes of treatment, same result was attained. With this ion treated specimens of Au-Ag-Pd alloy sandblasted, the adhesive bond strength of above 200 kgf/cm2 was maintained after 100,000 thermocycles.

Acrylic Resins↗