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Biomedical subjects

Y Chiba

Publications and source records attributed to Y Chiba.

At least 181 records · Page 10Linked to original sources
PubMed1994

Chronobiological analysis of a new clock mutant, Toki, in Drosophila melanogaster.

We have isolated a new semidominant clock mutant Toki on the second chromosome in Drosophila melanogaster. This mutant differs from the wild-type Canton-S in several properties as follows. Larger values are obtained in the phase angle difference (phi, the time from lights-off in a 24-hr light-dark cycle to an activity offset), the ratio of activity time to rest time (alpha/rho) and the activity level. The free-running period (tau) is 25.3 hr, one hour longer than in the wild-type. In the phase response curve (PRC), the ratio between the delay and the advance portion is larger and the cross-over point occurs later, although there is no difference in amplitude of the mutant's PRC (Type I). The rhythm is more sensitive to the light intensity, becoming obscure in darker condition. Toki interacts with other clock mutations, pers, perL and And, in such a way that tau s associated with these three X-linked mutations are lengthened and phi values become smaller.

Analysis of Variance↗
PubMed1994

[A case of bilateral coronary-pulmonary artery fistula with multicystic saccular aneurysms].

A 71-year-old woman was admitted to our hospital for evaluation of a chest X-ray abnormality. Heart murmur was not heard. Chest X-ray showed a bulge with calcification at left third arch. Chest computed tomography revealed contrast enhancement of masses, which appeared to originate from the vascular system. Coronary angiography demonstrated multicystic aneurysmal dilatation of a coronary artery fistula originating from the proximal left descending and right coronary artery. Electrocardiography showed no remarkable findings and a treadmill exercise test showed no significant ST-T change. The size of the mass of 3 cm in diameter on chest X-ray remained the same for two years. We concluded that surgery was not necessary immediately. In Japan, nineteen cases of coronary-pulmonary artery fistula with multicystic saccular aneurysms have been reported in the literature, including our case. The majority of these cases are elderly women from fifty to sixty years old.

Aged↗
PubMed1994

Poliomyelitis surveillance in Shandong Province, China, 1990-92.

In Shandong Province, China, programmes were initiated in 1991 for mass immunization against poliomyelitis and for the immediate reporting of acute flaccid paralysis (AFP). The incidence of non-poliomyelitis AFP was found to be 0.46-0.61 cases per 100,000 children per annum. It appeared that illness resembling the Guillain-Barré syndrome was underreported. The incidence of such illness peaked among children aged 2-3 years. Although laboratory investigations have improved, in 1992 they were still inadequate in nearly a third of confirmed poliomyelitis cases. As the prevalence of wild poliovirus declines in China, reliable laboratory support needs to be established and adequately sensitive and specific AFP surveillance be developed if poliomyelitis is to be eradicated.

Adolescent↗
PubMed1994

Effect of intermittent deep hypothermic circulatory arrest on brain metabolism.

The effect of intermittent systemic reperfusion during deep hypothermic circulatory arrest was investigated in dogs to learn how the total arrest period may be prolonged. The animals were cooled on cardiopulmonary bypass to 18 degrees C and divided into the following three experimental groups: group I (n = 7), 60 minutes of uninterrupted circulatory arrest; group II (n = 7), 120 minutes of circulatory arrest with 10 minutes of intermittent systemic perfusion every 30 minutes during the arrest period; group III (n = 7), 120 minutes of circulatory arrest with 10 minutes of intermittent systemic perfusion every 20 minutes during the arrest period. Cerebral oxygen extraction rate increased significantly during the arrest periods (p < 0.05) and returned to normal after each 10-minute period of systemic reperfusion in every group. During circulatory arrest, cerebral excess lactate increased in a time-dependent manner after 20 minutes (r = 0.78; p < 0.001). Anaerobic metabolism did not increase throughout the circulatory arrest period in group III, although it increased significantly in groups I and II (p < 0.05). The present data demonstrate that cerebral energy metabolism becomes predominantly anaerobic within the first 20 minutes of deep hypothermic circulatory arrest. The present findings suggest that intermittent systemic recirculation for brief 10-minute periods every 20 minutes during circulatory arrest should prevent cerebral anaerobic metabolism during long periods of arrest that are required to complete complicated surgical repairs.

Animals↗
PubMed1994

Inhibition of antigen-induced airway hyperresponsiveness in rats: effects of ozagrel (a thromboxane A2 synthase inhibitor) and of CV-3988 (a platelet activating factor antagonist).

The effects of ozagrel, a thromboxane A2 (TXA2) synthase inhibitor, and CV-3988, a platelet activating factor (PAF) antagonist, was investigated on the repeatedly antigenic challenge-induced airway hyperresponsiveness (AHR) in rats. Rats were actively sensitized with DNP-Ascaris antigen and received 3 inhalations of antigen (challenges) or saline (sensitized control) every 48 hr. These animals were also pretreated with ozagrel (100 mg/kg, p.o., 30 min before), CV-3988 (3 mg/kg, i.v., 5 min before) or respective vehicle (water and saline, respectively) before each inhalation of antigen or saline. The in vivo airway responsiveness to cumulatively inhaled acetylcholine (ACh; 0.001-0.03%, each for 3 min) was measured 24 hr after the last inhalation of antigen or saline under anesthesia. A marked AHR was observed after repeated antigenic challenge when compared with the sensitized control group (5.5-9.5 times in order). This AHR was significantly, but partly, attenuated by pretreatment with ozagrel although this treatment alone had no effect on the airway responsiveness to inhaled ACh in sensitized control animals. On the other hand, CV-3988 had no inhibitory effect on this AHR. These findings suggest that TXA2, but not PAF, is one of the most important mediators participating in the pathogenesis of the antigen-induced AHR in rats.

Acetylcholine↗
PubMed1994

[A case of fistula-cancer response to arterial chemoembolization].

Arterial chemoembolization was performed three times preoperatively for cancer associated with fistula-in-ano for diminishing the postoperative surgical tissue defect of the perineum. Partial response of the tumor to this treatment was confirmed by computed tomography. A sixty-two-year-old male patient recognized a mass in the perineum one and a half years ago. He had suffered from fistula-in-ano for thirty years. The mass increased its size and formed a tumor in the bilateral buttocks (12 x 9 cm and 9 x 9 cm in diameter). Biopsy specimen showed a moderately differentiated adenocarcinoma. Angiography showed a hypervascular tumor stain. The main feeders to the tumor were the superior rectal artery and bilateral internal iliac artery. Arterial chemoembolization was performed three times through the right and left internal iliac artery with Gelfoam particle. Arterial infusion chemotherapy was added through inferior mesenteric artery and bilateral internal iliac artery with a total 120 mg of adriamycin and 1,500 mg of 5-FU simultaneously. The tumor decreased in size to 44% of the preoperative size by the treatment. A radical operation was performed following the preoperative treatment. Preoperative arterial chemoembolization for cancer associated fistula-in-ano was considered to be helpful for local control.

Adenocarcinoma↗
PubMed1994

[Cooperation between clinical departments and tissue pathology department].

The author discussed some points where the staff in clinical departments could cooperate with the tissue pathology department to facilitate good quality control, (hereafter abbreviated as QC) from the stand point of a staff in internal medicine or gastroenterology. Remarks on general matters such as necessity of QC system at the ward where nurses are usually engaged in the treatment of the specimens for clinical laboratory. As to QC on tissue pathological diagnosis, inter-hospital surveillance is inevitably important. However, this has not been done because of defects in philosophy of Japanese medical insurance and in facts of medical education. At postmortem examination, the clinician would like to expect the pathologist to have a thoughtful consideration to convenience of the family of the dead. The tissue examinations of the biopsy specimens from GI endoscopy in the author's department are summarized as follows. In 1993, biopsy rates was 26.1% among 1726 patients done upper GI endoscopy. It was 42.4% in 536 patients done lower GI endoscopy. Group IV & V in the histological grade of malignancy account for 13.1% of 450 cases in upper GI specimens. Group 4 & 5 account for 16.3% of 226 cases in lower GI specimens. The frequency of specimens with malignancy taken by each endoscopist did not reveal any difference in the technical skill of each endoscopists, neither did the average number of specimens obtained in one occasion by each endoscopist. On 28 patients, biopsies were done in multiple occasions in a year. The rate of false negative in initial biopsy was 1.4% in 445 cases with which neoplasms were suspected.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Laboratory Techniques↗
PubMed1994

[Dose effects on vital parameters of guinea pig by continuous administration of cisplatin].

A wide used anti-neoplasmic agent, cisplatin (CDDP), injures normal organs dose-dependently by its toxicity. The mechanisms of organ injuries have been studied to prevent and rescue patient conditions. We analyzed the relation between CDDP doses and onset of organ injuries to clarify the mechanism of CDDP toxicity. The onset doses to cause organ injuries were calculated using weekly collected vital parameters of 18 male guinea pigs which were injected CDDP (2 mg/kg/day, 5 times/week) intraperitonealy until the death of animals. Correlations between the values of vital parameters and CDDP doses and applicative survival curve method were used to estimate the onset doses. Abnormal changes in iron metabolism and auditory organ were first noted at 10.2 mg/body and 10.8 mg/body of CDDP, respectively. The change in the salivary glands were noted at 15 mg/body. Renal injury started at 19.5 mg/body, and damages to the bone marrow started between 19.7 mg/body to 33.6 mg/body of CDDP. The minimal dose of liver dysfunction was 21.3 mg/body. It is concluded from these results that 1) the onset of organ injury depends on the dose of CDDP, and 2) the order of such injuries was iron metabolism, auditory organ, the salivary glands, kidney, the bone marrow, and the liver in guinea pigs, 3) Other organ injuries might be detected to clarify hearing levels during chemotherapy because those were noted following auditory damage except iron metabolism.

Animals↗
PubMed1993

A new method for coronary artery reconstruction in patients with recurrent aortic prosthetic valve endocarditis and an inaccessible coronary arterial system.

A new approach to the problem of recurrent infection of an aortic valve prosthesis in a patient with an inaccessible coronary arterial system is presented. The coronary arteries were reconstructed by anastomosing a looped ringed-PTFE graft to the left and right coronary ostia within the aorta, and the graft was withdrawn from the aorta just above the ostia. Then the top of the looped graft was anastomosed to the aorta above a translocated aortic prosthesis. This procedure is most likely to be useful in the treatment of recurrent aortic prosthetic valve endocarditis which has dense pericardial adhesion secondary to multiple cardiac operations. Aortic prosthetic valve endocarditis frequently is associated with a paravalvular ring abscess which may destroy the normal annulus. In these cases, translocating the aortic valve to the ascending aorta, and placing saphenous vein bypass grafts to the right and the left anterior descending coronary artery may be required. However, the coronary arteries may not be accessible following multiple operations. The following case illustrates a new solution to the problem how to translocated the aortic valve and reconstruct the coronary arteries in a patient with an infected aortic root and inaccessible coronary arteries.

Adult↗
PubMed1993

En bloc resection for cancer of the gastric cardia without thoracotomy.

Thirty-five consecutive patients underwent en bloc resection of cardia cancer without thoracotomy. All tumors were adenocarcinoma. The operative procedure involved wide resection of the peri-hiatal diaphragm, dissection of the upper abdominal and lower mediastinal lymph nodes, and resection of the stomach including a portion of the lower thoracic esophagus without thoracotomy. The resection area of the diaphragm included not only the crural muscle as in other methods, but also the diaphragmatic tissue surrounding the esophageal hiatus. Through the enlarged hiatus, dissection of the mediastinum was possible up to the carina from the abdominal cavity. The mediastinal node stations were affected in 25% of patients whose tumor invaded to the serosa. Hypotension with or without atrial arrhythmias and pleural tears occurred during surgery in 20 patients (57%) and in 18 patients (51%), respectively. Postoperatively, hypoxia requiring reintubation developed in 7 patients (19%), pleural effusions needed tube drainage in 16 patients (46%), atelectasis in 5 patients (14%), and anastomotic leaks in 3 patients (9%). They were all successfully treated. The cumulative 5-year survival rate for 21 patients with stages I (2 patients), II (9), and III (10) diseases was 62%, whereas none of the patients with stage IV disease lived for more than 2 years after surgery. Because thoracotomy is avoided, the procedure is better tolerated by debilitated patients. We believe this technique is a reasonable and safe alternative to the left thoracotomy approach for resection of cancer of the gastric cardia.

Adenocarcinoma↗
PubMed1993

The carbohydrate moiety of the acid carboxypeptidase from Aspergillus saitoi.

Acid carboxypeptidase from Aspergillus saitoi is a glycoprotein that contains both N- and O-linked sugar chains. The N-glycanase released high-mannose type oligosaccharides that were separated into eight components on HPLC. One, which had a unique structure of Man11GlcNAc2, was characterized. Mild alkali treatment of the carboxypeptidase, under conditions that effect beta-elimination, yielded D-mannose. Deglycosylation of the carboxypeptidase with endo-beta-N-acetylglucosaminidase and alpha-mannosidase effected the reduction of the molecular mass from 72 kDa to 60 kDa. Partial changes of CD spectra of the native and the deglycosylated enzymes indicate that some conformational changes on the peptide of the enzyme occurred after deglycosylation. Other enzymatic properties, such as catalytic activity, pH, and thermal stability and resistivity to protease digestion, did not appear to change. Tunicamycin halted secretion of the carboxypeptidase extracellularly.

Aspergillus↗
PubMed1993

Suppression of the lordosis reflex of female rats by efferents of the medial preoptic area.

In freely moving, estrogen- and progesterone-treated ovariectomized female rats, electrical stimulation of the medial preoptic area, which had been isolated dorsally from the septum by a horizontal knife cut (roof cut), caused immediate interruption of the lordosis reflex, a principal component of female reproductive behavior in this species. Neither the knife cut nor the stimulation affected their proceptive interactions with the males. Lordosis was interrupted in a graded manner in response to increased stimulus intensity, with a threshold at 30 microA. The optimal frequency was at 50-100 Hz. Lordosis was reinstated promptly by the termination of current application. The rapid time course distinguished the stimulation effect in the rats with the roof cut from that in the intact control animals, which was slow in its onset and recovery. In the sham-operated animals, an adjunct bilateral cut of the stria terminalis was sufficient to restore the rapid response as in the roof-cut animals. The roof-cut animals were sensitive to lower doses of estrogen than those without the knife cut; therefore, the preoptic area appears to be a separate entity from the septum in the inhibitory control of lordosis. The elimination of facilitatory neural components for this reflex, which enter the preoptic area dorsally via the stria terminalis, might be responsible for the prompt and exaggerated stimulation effect in the roof-cut animals.

Afferent Pathways↗
PubMed1993

Strain differences in change in airway responsiveness after repeated antigenic challenge in three strains of rats.

1. The strain differences in 2,4-dinitrophenylated-Ascaris antigen-induced airway hyperresponsiveness (AHR) were investigated in three strains of rats: Brown-Norway (BN), Long-Evans Cinnamon (LEC) and Wistar. 2. Fourty-eight hour-passive cutaneous anaphylaxis titers after repeated challenge were highest in BN and lowest in LEC. 3. Twenty-four hours after the last challenge, a marked AHR and significant increase in wet/dry weight ratio of the main bronchus were observed only in Wistar. 4. Only the isolated bronchus of the challenged Wistar among the strains showed hyperresponsiveness to acetylcholine. 5. Wistar may be the best strain for antigen-induced AHR.

Acetylcholine↗
PubMed1993

Entrainability of circadian activity of the mosquito Culex pipiens pallens to 24-hr temperature cycles, with special reference to involvement of multiple oscillators.

Entrainability of the circadian rhythm of mosquito flight and locomotor activity was investigated by giving a 24-hr temperature cycle (28 degrees C for 16 hr, 23 degrees C for 8 hr) to the free-running rhythm or by shifting the temperature cycle. The phase angle difference between the entrained rhythm and the temperature cycle depended on the free-running period, but not on the circadian phase at which the temperature cycle started. The rhythm transients (advancing or delaying) to entrainment depended on phase, but did not depend on either the phase or the free-running period for their average speed. We postulate that flight and locomotor activity in the mosquito may be controlled by two circadian oscillators moving in different directions in response to the temperature cycle. It is likely that at least one of the oscillators is diphasic.

Adaptation, Physiological↗