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Biomedical subjects

R Hashimoto

Publications and source records attributed to R Hashimoto.

At least 109 records · Page 6Linked to original sources
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↗
PubMed1991

Long-term depressor effects of catecholamine neuronal grafts in the third ventricle of the brain in normotensive rats.

Neuronal tissue containing A-6 group noradrenalin (NA) neurons of the locus ceruleus, or A-10 group dopamine (DA) neurons of the substantia nigra, was grafted into the third ventricle at the level of the preoptic-anterior hypothalamic region, in normotensive male rats. A significant and long-lasting depressor effect was shown in rats with either graft. In rats with an NA neuron-rich graft, plasma concentrations of arginine-vasopressin (AVP), plasma renin activity (PRA), and corticosterone (CS) decreased significantly, whereas in rats with a DA neuron-rich graft, AVP and PRA concentrations also decreased significantly but CS showed no significant change. Neither NA nor adrenalin in plasma changed significantly in rats with either graft.

Animals↗
PubMed1991

The activity of catecholamine synthesis in the hypothalamus of female normotensive Wistar Kyoto and spontaneously hypertensive rats.

The activity of catecholamine synthesis in the hypothalamus, as determined by the rate of 3,4-dihydroxyphenylalanine (DOPA) accumulation after the administration of a DOPA decarboxylase inhibitor, was compared among Wistar, spontaneously hypertensive (SH), and genetically matched normotensive Wistar Kyoto (WKY) rats. DOPA accumulation in the median eminence, an index of the activity of tuberoinfundibular dopaminergic neurons, was greater in SH rats than Wistar and WKY rats while DOPA accumulation in the medial preoptic area was smaller in Wistar rats than SH and WKY rats. No strain difference was found in DOPA accumulation in the corpus striatum, which represents the activity of nigrostriatal dopaminergic neurons. These results suggest that there are differences in catecholamine synthesis in the hypothalamus not only between SH and WKY rats but also between WKY and Wistar rats.

Animals↗
PubMed1991

Intrasellar cavernous angioma in neurofibromatosis.

A case of neurofibromatosis complicated by a large intrasellar (pituitary) cavernous angioma is reported. Vascular abnormalities, consisting of smooth muscle cell proliferation in the intima of the intermediate and small arteries, were also observed in branches of the renal and pulmonary arteries. An association between neurofibromatosis and intracranial cavernous angioma is discussed.

Autopsy↗
PubMed1991

Canopy development in young sugi (Cryptomeria japonica) stands in relation to changes with age in crown morphology and structure.

In young sugi (Cryptomeria japonica D. Don) stands, crown shape (crown length/crown diameter) ratio, average branch inclination, and spatial density of foliage in the crown increased with stand age. Within crowns, foliage distribution increased from the apex downward and, until crown closure, reached a maximum near the crown base. After crown closure, the maximum occurred near the middle of the crown. In each stand, foliage distribution in the canopy showed almost the same vertical change over time as it did in individual crowns. The vertical distribution of foliage in the canopy moved upward with stand age, accompanied by an increase in canopy depth and leaf mass. The shape of the vertical distribution was almost symmetrical between the upper and lower halves in the closed stands, although slightly skewed downward. The logarithm of average spatial density decreased linearly as cumulative leaf mass increased with distance from the top of the canopy. The total cross-sectional area of the crowns exceeded the stand area from the middle of the canopy downward in the closed stands because of crown overlap. However, partly because of changes in crown morphology and structure, the increase in leaf mass with stand age did not always cause more severe crown competition.

Journal Article↗
PubMed1991

Monotherapy for childhood epilepsies with zonisamide.

Zonisamide was tried on 44 children, 18 girls and 26 boys, from 8 months to 15 years of age at the start of the trial. In 6 children the drug has been stopped because of side effects. The drug was introduced at a dose of 2-4 mg/kg/day and increased to 12 mg/kg/day unless a satisfactory response occurred at a lower dose. A 100% control of seizures was achieved in 5 of 5 cases of idiopathic generalized epilepsies, in 7 of 8 cases of symptomatic generalized epilepsies, in one of one case of idiopathic partial epilepsies, and in 17 of 24 cases of symptomatic partial epilepsies. The main side effect was drowsiness, especially during the introduction.

Administration, Oral↗
PubMed1991

Isolated central nervous system arteriopathy with multiple aneurysms in an adolescent. A case report.

A 17-year-old male suffered recurrent subarachnoid hemorrhages due to multiple aneurysms in the distal branches of the cerebral arteries. Autopsy revealed arteriopathy as well as the aneurysms. The arteriopathy was widespread, affecting the distal branches of small and medium-sized muscular cerebral arteries, as well as the anterior and posterior spinal arteries, and vasocorona. The arteriopathy was characterized by prominent intimal thickening, discontinuity or absence of the internal elastic lamina, and thinning and/or disappearance of smooth muscle in the tunica media with fibroplasia. Slight intimal thickening was also observed in the arteries of the circle of Willis and its major branches, as well as in the basilar artery. However, the arterioles, venules and veins showed no remarkable features. The arterial lesions were found only in the central nervous system. The multiple aneurysms in the distal branches of the cerebral arteries, which had produced the main symptoms and clinical signs, were due to the arteriopathy.

Adolescent↗
PubMed1991

Chromosome analysis of postimplantation stage embryos for studying possible causes of developmental abnormalities in nonobese diabetic mice.

The chromosomes of postimplantation stage embryos of nonobese diabetic (NOD) mice were analyzed to investigate the causal mechanism of congenital anomalies in diabetic pregnancies. Postimplantation stage embryos (day 12 of gestation) in diabetic (NOD-DM) and nondiabetic (NOD-N) NOD mice had either a high or low incidence of chromosomal abnormalities. A large majority of externally normal embryos from NOD-DM and NOD-N mice had low incidences. A high incidence of chromosomal abnormalities was found in externally abnormal embryos of NOD-DM and NOD-N mice, and in a smaller number of externally normal NOD-N and NOD-DM embryos. No control ICR embryo manifested a high incidence of chromosomal abnormalities. In the NOD-DM embryos, the chromosomes appeared to be influenced by long-term maternal diabetic conditions, while high incidences of chromosomal abnormalities in the NOD-N embryos suggested a probable cause by other factor(s) (e.g. a genetic predisposition) or by a very mild diabetic condition because the NOD-N mice were prediabetic.

Animals↗
PubMed1991

Effects of intraventricular injection of delta receptor antagonist ICI 154, 129 on the secretion of luteinizing hormone and prolactin in the proestrous rat.

In order to ascertain the role of delta receptors in the control of gonadotropin secretion, a preferential delta receptor antagonist ICI 143,129 was microinjected into the third ventricle through chronically implanted cannulae and the effects on the serum concentration of luteinizing hormone (LH) and prolactin (PRL) were determined in female rats in proestrus. When the injection was given at 1030 h, ICI 154,129 (50 micrograms) exerted no significant effects on either LH or PRL. However, in the rat given a microinjection of ICI 154,129 at 1300 h, an afternoon rise in LH occurred in advance and was of greater magnitude, with the peak time more than 1 h earlier and the peak amplitude approximately 100% greater than that in the control rat, respectively. The injection also suppressed the PRL rise during the plateau phase. The results indicate that delta receptors are involved in the mediation of the inhibitory influence of endogenous opioids on the surge of LH in proestrus, and that delta receptors mediate the facilitatory influence of opioids on the PRL surge during the plateau phase.

Analysis of Variance↗