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Biomedical subjects

Y Hayashida

Publications and source records attributed to Y Hayashida.

At least 145 records · Page 8Linked to original sources
PubMed1984

Sensitivity of rapidly acting arterial pressure control system in conscious adult rabbits at different ages.

Changes in sensitivity of the rapidly acting arterial pressure control (AP) system with aging were investigated. Two catheters, one for pressure measurement and the other for inducing hemorrhage from the aorta, were chronically implanted in 25 rabbits from the same colony (aged 6 to 30 months). A few days after the operations, each animal was quickly bled (2 ml/kg body weight) while it was conscious. The hemorrhage experiment was repeated 16 times and the mean arterial pressure responses were sampled with an A/D-converter and stored in a digital computer, the 16 strings of data being pooled for each animal. The overall open-loop gain (G) of the AP-system was estimated from the individually pooled responses. In the present study, aging exerted no significant effect on the value of G (7.1) as evaluated by Kruskal-Wallis' non-parametric one criterion variance analysis (p greater than 0.05). The reflex sensitivity of the AP-system over the pressure ranges used in this experiment thus appears to be unaffected by aging over the range from 6 to 30 months.

Aging↗
PubMed1984

[Detection of resection line in early gastric cancer].

In patients with multiple gastric cancer and superficial spreading type gastric carcinoma (abbreviated as S.S.C.) accompanied by IIb, the remnant stomach is sometimes cancer positive. Our study population consisted of 44 patients with multiple early gastric cancer and 63 patients with depressed type S.S.C. The gastric mucosa was classified into 3 types according to the surrounding mucosal atrophy, 1) pyloric gland zone, 2) intermediate zone, 3) fundic gland zone. All lesions of multiple early gastric cancer and S.S.C. were located in the pyloric gland zone or the intermediate zone. The depressed type S.S.C. did not invade the fundic gland zone. Therefore, knowledge about the extend++ of surrounding mucosal atrophy is required for the proper diagnosis of early gastric cancer and the surgeon must recognize the relationship between the glandular border line and resection line.

Gastrectomy↗
PubMed1983

Effects of temperature on denervated carotid body (glomus) cells.

Cat carotid bodies were denervated for 3-31 days by sectioning the carotid nerve. The normal response of glomus cells to cooling by about 6 degrees C, namely, membrane depolarization and reduced input resistance (Ro) was altered. At 3 days, cooling induced normal depolarization although Ro decreased more markedly. At 7 days, cooling depolarized 53% of the cells which was accompanied by variable Ro changes. Forty-seven percent of the cells were hyperpolarized and their Ro increased. At 16 days, a fall in temperature depolarized 25% of the cells which showed variable changes in Ro, whereas the rest showed hyperpolarization and increased Ro. At 31 days, cooling weakly depolarized 64% of the cells together with a small reduction in Ro whereas 28% showed some hyperpolarization and larger Ro. It is concluded that sensory denervation alters the membrane of glomus cells, the preneuronal component of the receptor complex.

Animals↗
PubMed1983

Overall open-loop gain of rapidly acting arterial pressure control system in rabbits.

We estimated the overall open-loop gain of the rapidly acting arterial pressure control system without surgically or pharmacologically opening the reflex loop in rabbits. Animals anesthetized by intravenous injection of Nembutal (27.5 mg X kg-1 body weight) and heparinized were bled by 2 ml X kg-1 body weight within 1-2 s through a catheter inserted into the aortic arch. Arterial pressure change after the quick mild hemorrhage was monitored via a catheter placed in the right subclavian artery for more than 2 min. The overall open-loop gain of the lumped arterial pressure control system determined from the mean arterial pressure response to the hemorrhage was 7.3. It was almost constant over the range between 12.9 and 22.2 kPa systemic pressure.

Animals↗
PubMed1983

Neural activities during replacement of blood with fluorocarbon emulsion.

Exchange transfusion of the blood with fluorocarbon (FC) emulsion was conducted in the cat ventilated spontaneously with high oxygen tension gas, and responses of various neural activities to this replacement were studied. Animals survived in good physiological condition, at hematocrit values of less than 5%, more than 3 hours after the end of the FC transfusion. Electroencephalographic activity and afferent impulses of the carotid sinus nerve increased and sympathetic renal nerve activities decreased compared with the control activities before the replacement, indicating no impairment in the reflexogenic control of the respiratory and circulatory systems. Moreover, the amplitudes of the sensory evoked cortical potentials increased with lower hematocrit values during FC treatment. However, early components of auditory brain stem responses did not increase as markedly compared with the cortical responses. We concluded that the general condition of the animals and the neural responses examined were well preserved after FC emulsion exchange transfusion.

Afferent Pathways↗
PubMed1983

The effects of pulmonary circulation pulsatility on the impedance cardiogram.

To study the effects of pulmonary blood flow on the impedance cardiogram, the pattern of pulmonary blood flow was alternated from pulsatile to non pulsatile, or the reverse, using our extracorporeal bypass-method on anaesthetized dogs. The thoracic impedance cardiogram was recorded from band electrodes placed around the neck and upper abdomen. During nonpulsatile pulmonary blood flow, the height of the diastolic phase of the delta Z wave was lower than that during pulsatile pulmonary blood flow. The area under the impedance curve decreased during nonpulsatile pulmonary blood flow. This appeared to be more obvious as the pulmonary arterial flow was reduced. The results suggest that the pulmonary blood flow might have substantial effects on the impedance cardiogram.

Animals↗
PubMed1982

Investigation of genetic markers in a true hermaphrodite with chi 46,XX/46,XY.

We documented a new case of chi 46,XX/46,XY true hermaphroditism substantiated by the evaluation of chromosomal heteromorphism in banded preparations. The patient, a 12-year-old Japanese boy with ambiguous external genitalia, was seen because of abnormal breast development. Surgical exploration showed the right gonad to be an ovotestis and the left gonad to be an ovary. Cytogenetic studies revealed cell admixtures of 46,XX and 46,XY karyotypes in peripheral lymphocytes, skin fibroblasts, and gonadal fibroblasts. From the pedigree studies, the paternal double genetic contributions were evidenced by the differences of sex chromosomes and the blood group types for the ABO and MNSs systems in the two cell lines of the patient. The maternal double genetic contributions were confirmed by the inheritance of Q-fluorescent markers on chromosomes 13 and 22 and by alleles for the Kidd blood group system.

Blood Grouping and Crossmatching↗
PubMed1982

Immunocytochemical identification of human chorionic gonadotropin- and alpha-fetoprotein-producing cells of hepatoblastoma associated with precocious puberty.

A one-year-five-month-old boy with hepatoblastoma producing both human chorionic gonadotropin (hCG) and alpha-fetoprotein (AFP) is presented. Histologically, the primary tumor was mainly composed of well differentiated hepatoblastoma cells, with minor areas of poorly differentiated cells. Immunoperoxidase staining of the tumor for hCG and AFP showed that a few well differentiated, fetal type cells and multinucleated giant cells were positive for hCG, and AFP was never stained in the same cells. In areas where cells were poorly differentiated, positive reactions for either hCG or AFP were not observed. Electron microscopic studies revealed focal aggregates of cytoplasmic cored vesicles in some tumor cells, similar to secretory granules.

Carcinoma, Hepatocellular↗
PubMed1982

Follow-up studies of children treated with a long-term intravenous nutrition (IVN) during the neonatal period.

The outcome of the 28 children treated with intravenous nutrition (IVN) for more than 4 wk during the neonatal period was investigated. Ten of the 28 children had a normal length of small bowel (group 1) and the other 18 children had a short bowel (group 2). Eight of these 28 children (4 in group 1 and 4 in group 2) died during or after cessation of IVN; three died from complication of IVN and 5 died from their initial disease. On physical examination, delay in catch-up growth was observed in the early postoperative period, particularly in children in group 2, but this diminished with time. Mental and emotional development showed both groups to be within the normal range, except for two children. Intellectual function was also normal in five children over the age of 4 yr who were examined. Hepatic dysfunction was noticed during IVN in 30.0% in group 1 and 66.7% in group 2, indicating that the longer the duration of IVN, the higher the incidence of liver damage. Furthermore, histologic abnormalities in these neonates lasted for a longer time. These results imply that long-term IVN during the neonatal period in surgical patients does not interfere with physical and developmental growth. However, careful and long-term follow-up of liver function after IVN is necessary.

Child↗
PubMed1981

Gradual occlusion of the portal branch with hepatic artery ligation for unresectable hepatic tumour in children.

For the surgical treatment of unresectable hepatic tumour in children we devised a method whereby the portal vein is gradually occluded. Using this new procedure, combined with ligation of the hepatic artery and intraarterial and systemic anticancer chemotherapy, there was a marked decrease in tumour size and hypertrophy of the contralateral lobe of the liver. For gradual occlusion of the portal vein we used the Ameroid constrictor, which consists of a casein derivative enclosed in a stainless steel jacket, and when applied the vessels will occlude within 7-10 days. The patients tolerated this procedure well; there was no occurrence of shock, the liver dysfunction was temporary and normal ranges were reverted to within 2-3 weeks after surgery. One patient treated in this way lived for 14 months after undergoing such surgery.

Animals↗