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Biomedical subjects

R Hashimoto

Publications and source records attributed to R Hashimoto.

At least 91 records · Page 5Linked to original sources
PubMed1994

The effect of exercise on plasma biopterin levels.

The plasma total biopterin and tetrahydrobiopterin levels of 29 normal volunteers were measured before and after exercise by ergometer, and those of 10 were also measured until 24 h after exercise. An increase of plasma total biopterin and tetrahydrobiopterin was observed only after strong exercise, which exhausted the subjects, the ratio of tetrahydrobiopterin to total biopterin not differing before and after exercise. The increase of plasma biopterins disappeared 2 h after exercise. The mechanism of the increase of plasma biopterins was thought to be different from that of patients with affective disorders.

Adult↗
PubMed1994

Changes in plasma tetrahydrobiopterin levels of depressives in depressive and remission phases: reconfirmed by measurement with an internal standard.

Plasma total biopterin and tetrahydrobiopterin levels of 10 normal controls and 10 patients with monopolar depression were measured with and without internal standard. The levels did not differ between the two methods. A significant increase of total biopterin levels and the lower ratio of tetrahydrobiopterin to total biopterin in the depressive phase were observed in the plasma of patients with depression compared to normal controls, and these changes in plasma biopterin tended to normalize in the remission phase.

Adult↗
PubMed1994

Microinjection of LHRH and its antagonistic analog into the medial preoptic area does not affect pulsatile secretion of LH in ovariectomized rats.

To gain a better understanding of the existence of an ultra-short feedback mechanism controlling LHRH secretion in the medial preoptic area (MPO), we examined the effects of microinjections of LHRH or the LHRH antagonist [D-pGlu1, D-Phe2, D-Try3,6] into the MPO on pulsatile secretion of LH in ovariectomized rats and on the surge of LH secretion in proestrous rats. Neither the injection of 10 ng LHRH nor 100 ng its antagonist into the MPO had any effect on pulse frequency or the mean LH concentration in ovariectomized rats. The injection of 100 ng LHRH antagonist or 10 ng LHRH delayed or advanced, respectively, the LH surge in proestrous rats. Taking these results together with our previous report, the present study indicates that 1) endogenous LHRH in the MPO is involved in the ultra-short feedback regulation of LHRH release and 2) the ultra-short positive feedback mechanism in the MPO acts at the time of the proestrous LH surge but not under a hormonal milieu as in ovariectomized rats.

Animals↗
PubMed1994

Fungal metabolites. Part 14. Novel potent immunosuppressants, mycestericins, produced by Mycelia sterilia.

Mycestericins A, B, C, D and E were isolated from the culture broth of Mycelia sterilia ATCC 20349 along with thermozymocidin (= myriocin). Their structures were elucidated on the basis of spectroscopic studies and chemical evidence. The acetate of mycestericin C was identical with the acetate of 6,7-dihydromyriocin. Mycestericins suppressed the proliferation of lymphocytes in the mouse allogeneic mixed lymphocyte reaction, with a potency similar to that of myriocin.

Animals↗
PubMed1994

[Intrabronchial neurilemmoma: a case report].

A 62-year-old woman who was pointed out abnormal shadow at left middle lung field in chest X-ray was followed up as a hamartoma from 1989. In this period, the tumor was growing up in chest X-ray and occupying the left segmental bronchus (B3) in bronchofiberscopic study. It was suspected neurilemmoma by the final biopsy examination. Left upper lobectomy was performed and pathohistological diagnosis was typical neurilemmoma that consist of Antoni type A and Antoni type B. Intrapulmonary or intrabronchial neurilemmoma is rare and only 20 cases have been reported in the Japanese literature.

Bronchial Neoplasms↗
PubMed1993

Ultrastructure of the developing stomach in human embryos.

Ultrastructural development of the stomach was studied by light, scanning electron and transmission electron microscopy, using 19 human embryos at Carnegie stages from 14 to 23 (6.8-28.0 mm in crown-rump length, 5 to 8 weeks of gestation). The precise time of appearance of differentiated characteristic structures was examined electron microscopically. The first gastric pit, with radially arranged epithelial cells beneath which the basement membrane bulged into the mesenchyme, was observed on the lesser curvature at stage 22. Although the mesenchymal condensation which would develop into the inner circular muscle layer appeared at stage 18 onward, cytoplasmic myofibrils were not observed until stage 22. Nerve fibers were first observed at stage 16, and at later stages they gathered into bundles to form a nerve plexus external to the developing inner circular muscle layer. On the basis of accurate timing of the appearance and the mode of development of these structures, possible relations between developing gastric layers were discussed. Histocytochemically, glycogen or other carbohydrates were demonstrated in the cytoplasm of the gastric epithelium throughout the stages examined. These carbohydrates were localized mainly in vacuole-like spaces in the basal part of the epithelial cells. This subcellular localization, and the amount of carbohydrate, did not change significantly during the observed embryonic period. In the serosa, carbohydrates were not detected at stages 14 and 15, but observed consistently within the vacuoles in the cytoplasm from stage 17 onward. No other layer of the embryonic stomach had detectable carbohydrates.(ABSTRACT TRUNCATED AT 250 WORDS)

Embryo, Mammalian↗
PubMed1993

Muscle pH/PCO2 monitoring.

The surface pH of skeletal muscle has been confirmed to be a sensitive indicator of peripheral muscle blood flow, but the development of a better electrode has been required. As a consequence, a unique and minute sensor was developed to measure muscle pH/PCO2. The purpose of this article was to evaluate this new monitoring device experimentally and clinically in order to clarify its effects, usefulness and specificity. Our experimental and clinical results showed that placement and measurements using the muscle pH/PCO2 monitor were easily and quickly accomplished without any complications. This small sensor provided an accurate assessment of vital physiologic functions and gave an early warning of clinical deterioration. The new monitor should be useful in pediatric surgery clinical management.

Animals↗
PubMed1993

[Usefulness of Vmax and time constant in the evaluation of left ventricular function immediately after cardiac operation].

It is difficult to evaluate the cardiac function accurately, immediately after cardiac operation, because of the restriction of measurements and the variations of loading. To evaluate the exact cardiac function during and after cardiac surgery, we examined the usefulness of unloaded maximal shortening velocity of contractile element (Vmax) and time constant of isovolumic pressure fall (TC) in the condition of hasty changing of preload and afterload. In our experiment, we used canines as our subject. Following the sedation of the canines, the left ventricular pressure (LVP) curve was recorded by using the catheter-tip manometer which was introduced into the apex of the heart. The LVP was measured in the following instances: 1) at control condition, 2) 5 minutes after the administration of dobutamine of 2 or 5 micrograms/kg/min, 3) 5, 10, 15, and 30 minutes interval after the ligation of the left anterior descending artery (LAD). In every situations, preload and afterload were changed by the temporary occlusion of the inferior vena cava or descending thoracic aorta. Vmax and TC were analyzed easily only from the LVP by the personal computer. We used Grunkemeier's method to calculate Vmax which was analyzed only from the LVP curve. We presumed that the mean value of Vmax analyzed by Grunkemeier's method was almost the same as the data by Mason's method by calculating the mean value from the given number of heart beats. Because the correlation of two methods was linear, and furthermore the slope of this regression line was 0.97 and the Y-intercept was 0.19. Vmax was the index that was comparatively independent from the loading condition.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[On the fluctuation of plasma biopterin levels for 24 h in normal controls].

Tetrahydrobiopterin (BPH4) is the cofactor for the pteridine-dependent monooxygenases, which play important roles in the biosynthesis of cateholamines and indolamines. These biogenic amines have been thought to be related to affective disorders, and the increase of total biopterin (BP) and the lower ratio of BPH4 to total BP were observed in plasma of patients with affective disorders. For the purpose of giving an explanation of these changes of plasma biopterin mentioned above in patients with affective disorders, the fluctuation of plasma biopterin levels for 24 h was measured by high-performance liquid chromatography with fluorescence detection by the method of Fukushima and Nixon in ten normal volunteers. The total BP and BPH4 levels in plasma at 9 am were the highest, and those levels at 1 am were the lowest. The range of the fluctuation of total BP with the passage of time was narrow compared with the range of the increase of total BP observed in the patients with affective disorders. Other factors in addition to the fluctuation of plasma BP for 24 h were thought to be related to the changes of plarma BP levels in the patients with affective disorders.

Adult↗
PubMed1993

[Computerized recording system during cardiopulmonary bypass utilizing the "GEM 6 PLUS analyzer"].

We developed a new computerized recording system to reduce artificial errors by perfusionists during cardiopulmonary bypass. This system included the efficient functions to record the progress of perfusion flow, perfusion pressure, urine output and temperatures from several sources. Furthermore, it could automatically record considerable data of the "GEM 6 PLUS analyzer" which was developed for monitoring of pH, PCO2, PO2, BE, Ca2+, K+ and hematocrit during cardiopulmonary bypass. We considered it very important that the errors of hematocrits associated with electrolytic concentrations. Therefore, we corrected the hematocrit according to a formula based on our experiments, i.e., HCT = GEMHCT + 0.28 x ([Na+]+[K+]) -44. And also we expect that the "GEM 6 PLUS analyzer" will be improved to measure Na+ value in near future.

Body Temperature↗
PubMed1992

A case of mixed-type dysgerminoma with a high serum concentration of both human chorionic gonadotropin and alpha-fetoprotein in a child.

Dysgerminoma is divided into two types: pure and mixed. The mixed type is related to other various elements of germ cell tumors. We experienced a case of mixed type dysgerminoma with a high serum concentration of both human chorionic gonadotropin and alpha-fetoprotein. The patient was a 6 year old girl who was admitted to the Hamamatsu University School of Medicine with an abdominal mass. Laboratory investigations revealed elevated serum alpha-fetoprotein and high concentration of serum beta-human chorionic gonadotropin. The tumor originated from the left ovary. The histopathological diagnosis was dysgerminoma. Serum human chorionic gonadotropin and alpha-fetoprotein levels were useful markers in monitoring the response to treatment in this patient.

Angiography↗
PubMed1992

Timing and sequence of the events in the development of extraocular muscles in staged human embryos: ultrastructural and histochemical study.

The ultrastructure and the appearance of glycogen were studied in the extraocular muscles of 14 externally normal human embryos (Carnegie stages 13-21). At stage 16, myofibrils with an immature Z line and glycogen granules appeared in the cytoplasm of the myoblast. The myoblasts came into cluster at stage 18, and fusion between the myotubes was observed at stage 20. At this stage, an M line appeared in the myofibrils. At stage 21, an A band with a Z line and an H band with an M line were observed, the sarcoplasmic reticulum appeared in the cytoplasm of the muscle fibers and glycogen increased in volume in the cytoplasm. In the previous study, we showed that the muscle-specific isoenzymes, such as creatine kinase, beta-enolase and glycogen phosphorylase, appeared from stage 18 to 20 in the extraocular muscles. The previous findings and the present results suggest that the fusion of the muscle cells occurs in the period when some molecular markers of muscle differentiation are expressed in vivo.

Glycogen↗
PubMed1992

[Chest wall reconstruction with a prosthetic material molded from a extirpated specimen].

A new molding technique of the Acryl-resin Marlex-mesh sandwich method is described. After the wide extirpation of the chest wall, the defect size tends to grow up more larger than the specimen. For making a just fit size prosthesis, we cut off a cardboard as the same size as the specimen and the Acryl-resin Marlex sandwich is molded from the cardboard. Other some know-how are in the text.

Acrylic Resins↗