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Biomedical subjects

Y Oku

Publications and source records attributed to Y Oku.

At least 127 records · Page 7Linked to original sources
PubMed1991

Contribution of chemical feedback loops to breath-to-breath variability of tidal volume.

We tested whether chemical feedback loops contribute to the breath-to-breath correlations seen in respiratory cycle parameters. We have analyzed tidal volume (VT) of seven anesthetized, vagotomized, spontaneously breathing rats and the peaks of the 'integrated' phrenic neurograms (P) of another twelve anesthetized, vagotomized, paralyzed and artificially ventilated rats. Animals were studied while breathing 100% O2, 4% CO2 in O2 and/or room air. Our analysis consisted of fitting a first-order autoregressive (AR1) model to each measured variable in steady-state conditions. We found that: (1) breath-to-breath fluctuations of VT could be described by a first-order autoregressive model in which the fluctuation of VT on each breath from its mean level is correlated with that of the immediately preceding breath; (2) breath-to-breath fluctuations of P were not correlated with those of previous breaths, because successive values of P were uncorrelated random variables. Hypercapnia enhanced correlations in VT (3 rats) but not in P (12 rats). We propose that breath-to-breath correlations of VT in anesthetized, vagotomized and spontaneously breathing rats may reflect the effects of noise in respiratory chemical feedback loops.

Animals↗
PubMed1991

Chemotherapy of brain metastases from lung carcinoma: a controlled randomized study.

A controlled randomized study was carried out to evaluate the effects of chemotherapy in patients with brain metastases from lung carcinoma. One hundred patients were randomly divided into three groups at the time of diagnosis or after surgery for metastases. Group A received radiotherapy alone; Group B received radiotherapy and chloroethylnitrosoureas (methyl-CCNU, 100-120 mg/m2, or ACNU 80-100 mg/m2, every 6-8 weeks), and Group C received radiotherapy and a combination of chloroethylnitrosoureas and tegafur (300 mg/m2, daily). Of the 100 patients, 88 could be evaluated. The reduction rates of the tumors of the patients in whom tumor was not surgically removed or not totally removed were compared. Complete resolution of the tumor was noted in 29, 69, and 63% of the patients in Groups A, B, and C, respectively. Tumor regression of greater than or equal to 50% was seen in 36, 69, and 74% of the patients in Groups A, B, and C, respectively. The difference in the response rates of Groups A and C was statistically significant (P less than 0.05). Median survival after the start of treatment for brain metastasis was 27, 30.5, and 29 weeks in Groups A, B and C, respectively. There was 1 long-term survivor (more than 5 years) in Group A, 3 in Group B, and 1 in Group C. The main cause of death was deterioration attributable to the primary lesion or systemic metastasis, and no statistical difference was noted in survival time among the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1991

[Isolation of Vero toxin-producing Escherichia coli (VTEC) from imported meats].

One hundred and four samples of various imported meats obtained from the stores and supermarkets in Matsuyama-city and Iyo-city from November, 1987 to October, 1988 were examined and two strains of Vero toxin-producing Escherichia coli were isolated: one was from beef from Australia and the other was from pork from Canada. By bead-ELISA, it was confirmed that the strain from beef produced Vero Toxin 1 (VT1) and Vero Toxin 2 variant (VT2vh) and the strain from pork produced VT2vh. These results suggest that imported meats may be contaminated with VTEC and thus are possible sources of human VTEC infection, such as hemorrhagic colitis and hemolytic uremic syndrome.

Animals↗
PubMed1991

[The relationship between the aortic pulse wave velocity and osteoporosis in elderly women].

The relationship between arteriosclerosis and osteoporosis (OP) was assessed in 20 elderly women. The aortic pulse wave velocity (PWV) was used as the index of arteriosclerosis and bone mineral content (BM) of the vertebral body, which was measured by quantitative computed tomography, was used as an index of OP. PWV and BM showed a significant correlation with aging (PWV and age: r = 0.466, p less than 0.05, BM and age: r = -0.487, p less than 0.05). In the group in which the serum alkaline phosphatase (ALP) was higher than 180 IU/l (n = 11), there was a significant inverse correlation between PWV and BM (r = -0.728, p less than 0.02). On the other hand, there was no correlation between PWV and BM in the group in which ALP was lower than 180 IU/l (n = 9). These results suggest that in cases with OP and high levels of ALP, calcium (Ca) seems to be released from the bone system and transferred to the wall of the aorta. The mechanism and pathogenesis of this Ca transference is unknown and should be investigated.

Aged↗
PubMed1991

Phenotypic changes in hepatic mast cells accumulating around the metacestodes of Taenia taeniaeformis in rats.

Staining properties, kinetics and degranulation of the hepatic mast cells (HMC) accumulating around the metacestodes of Taenia taeniaeformis in the liver of rats were studied. Two different types of HMC, designated as Type I and Type II, could be classified according to histochemical properties and response to compound 48/80. Type I cells resembled mucosal mast cells (MMC), whereas Type II did not. HMC, mostly Type I, were observed from day 14 postinfection (PI), while Type II were seen only from day 28 PI. On day 28 PI, Type II represented a transitional staining pattern between MMC and connective tissue mast cells (CTMC). The ratio of Type II to Type I increased gradually with the course of infection and was about 1 to 1 on day 70 PI. At this time, most of the HMC that constituted Type II as well as CTMC could be stained with berberine sulfate. While the phenotypic change of HMC to CTMC was found in the middle and inner capsular layers, most of the HMC in the outer capsular layer maintained the phenotype of MMC. The present results suggest that hepatic mast cells increased as the MMC phenotype, then showed the heterogeneity in which the transitional form of mast cells emerged followed by the appearance of the CTMC type.

Animals↗
PubMed1991

Laboratory rodent models for the tapeworm-stage of Taenia saginata and other related taeniid species.

Attempts were carried out to establish alternative definitive host systems for Taenia saginata, T. crassiceps, T. hydatigena, Echinococcus multilocularis and E. granulosus, in rodents. Following oral inoculation of cysticerci or protoscoleces, the tapeworm-stage development and sexual maturation of the 5 taeniid species in the intestine of a golden hamster (GH) and Mongolian gerbil (MG), both treated with prednisolone, were examined. Sexually mature T. saginata tapeworms were recovered from MG pretreated with prednisolone. The life cycles of E. multilocularis can be completed in MG and T. crassiceps in both MG and GH. T. hydatigena and E. granulosus developed to a certain extent at the tapeworm stage in MG pretreated with prednisolone. Potential use of rodents as an alternative definitive host for taeniid species is discussed.

Animals↗
PubMed1991

Relationship between blood pressure and left ventricular mass in male patients with essential hypertension.

We performed retrospective study of the relationship between the severity and duration of hypertension and echocardiographically-detected left ventricular hypertrophy (echo-LVH) in patients with untreated essential hypertension. The subjects consisted of 92 untreated essential hypertensives who were observed for more than 5 years from the onset of diastolic hypertension (greater than or equal to 95 mmHg), and whose left ventricular (LV) mass index was measured at the end of the observation period. On the basis of the frequency of diastolic hypertension during the observation period, the population was categorized in 3 groups. In Group I (32 cases), diastolic hypertension was observed in more than 80% of blood pressures obtained throughout the entire observation period. In Group II (38 cases), diastolic hypertension was observed in 33 to 80% of the observation period. In Group III (22 cases), diastolic hypertension was observed in less than 33% of the observation period. The average diastolic blood pressure during the entire observation period in each group were 101.0, 96.0, and 90.7 mmHg in groups I, II, and III, respectively. The LV mass index was significantly higher in groups I (114.6 g/m2) and II (105.3 g/m2) than in group III (90.7 g/m2) (p less than 0.01). The prevalence of echo-LVH (more than 121 g/m2) was 34.4%, 18.4%, and 4.8% in groups I, II, and III, respectively. The average diastolic blood pressure in patients with echo-LVH (99.3 +/- 5.1 mmHg) was significantly higher than in patients without echo-LVH (95.7 +/- 4.7 mmHg). We concluded that the degree and duration of diastolic pressure elevation are closely correlated to the LV mass index.

Blood Pressure↗
PubMed1991

[A case of left coronary ostial obstruction due to syphilitic aortitis].

Coronary ostial stenosis is a rare lesion, which is a complication of syphilitic aortitis, Takayasu's aortitis, aortic valve disease, and familial hypercholesterolemia. We present a case of left coronary ostial obstruction due to syphilitic aortitis. A 67 years old man was admitted to our hospital for evaluation of a ten year history of angina on exertion. On physical examination, the only abnormal finding was a grade 2/6 high-pitched diastolic murmur. Coronary risk factor was not detected from biochemical results, but both the TPHA and FTA-ABS test were positive. Treadmill stress test showed more than 2 mm ST segment depression associated with chest pain. Coronary angiography revealed complete obstruction of left coronary ostium with good collaterals from the right coronary artery. The coronary arterial tree was otherwise normal. Furthermore, aortagraphy showed a moderate degree of aortic regurgitation. From the examination of previous reports including our own case, we think that the angiographic features of syphilitic coronary ostial stenosis can be summarized as below. 1. Coronary artery stenosis is generally limited to the ostium. 2. The grade of stenosis almost always shows more than 90% stenosis, and sometimes bilateral coronary ostium can be affected. 3. Aortic regurgitation is frequently noted, associated with coronary ostial stenosis.

Aged↗
PubMed1990

Growth of a Japanese isolate of Taenia crassiceps in intermediate and definitive hosts.

Higher infection rates were observed in gerbils and voles than in ICR mice after oral inoculation with eggs of a Japanese isolate of Taenia crassiceps. Asexual reproduction of T. crassiceps cysticerci was observed in all gerbils and voles infected i.p. with the cysticerci. However, ICR mice and Wistar rats were not suitable for the asexual proliferation of T. crassiceps. The hooks of cysticerci from mice were smaller than those from gerbils. In experimentally infected puppies, parasite development was noted as follows: strobilation and initial differentiation of the genital primordia on day 7 postinoculation (p.i.), appearance of the testes on day 9, observation of the ovaries on day 10, and development of the lateral branches of the uterus on day 15. The prepatent period was 27-31 days. After day 15 p.i., most of the worms were recovered from the middle third of the small intestine. The number of proglottids shed per day by each strobila was about 1. The number of eggs contained in a gravid segment was about 13,000.

Animals↗
PubMed1990

Demonstration of RNA N-glycosidase activity of a Vero toxin (VT2 variant) produced by Escherichia coli O91:H21 from a patient with the hemolytic uremic syndrome.

A new Vero toxin purified from Escherichia coli O91:H21 isolated from a patient with the hemolytic uremic syndrome (VT2vh) was shown to inhibit elongation factor 1-dependent aminoacyl-tRNA binding to ribosomes, resulting in inhibition of protein synthesis in rabbit reticulocytes. VT2vh, like Shiga toxin, VT1 and VT2, showed RNA N-glycosidase activity and cleaved the N-glycosidic bond of the adenosine residue at position 4324 in 28S ribosomal RNA.

Animals↗
PubMed1990

Long-term observation of cardiac function in Duchenne's muscular dystrophy. Evaluation using systolic time intervals and echocardiography.

Cardiac involvement is common in patients with Duchenne type muscular dystrophy (DMD). However, published reports of long-term follow-up studies in the same patients are very rare. The purpose of this study was to clarify the natural course of cardiac dysfunction in DMD, and to analyze the relationship between the deterioration of cardiac function and skeletal muscular function. The cardiac function was serially evaluated for 2-12 years in 34 patients with DMD. The systolic time intervals and echocardiography were used for evaluating the cardiac function. The PEP/ET (pre-ejection period/ejection time) of systolic time intervals significantly deteriorated in 9-12 years (p less than 0.001). The maximal systolic and diastolic endocardial velocity (MSEV and MDEV) and the D/S ratio of echocardiography significantly deteriorated in 5 years (p less than 0.001). The D/S ratio is the ratio of the mean systolic velocity and the mean diastolic velocity of the left ventricular posterior wall. In almost half the patients, the deterioration of these parameters was correlated with that of Swinyard's stage. The Swinyard's functional ability stage demonstrates the grade of the skeletal muscular dysfunction. However, there was no correlation between the deterioration of cardiac function and Swinyard's stage in the other half of the patients. Correlation coefficient in the whole group was 0.32 (p = n.s.) between the PEP/ET and Swinyard's stage, and was -0.15 (p = n.s.) between the D/S ratio and Swinyard's stage. Although the mean left ventricular ejection fraction calculated using echocardiography was slightly decreased for 5 years, no significant change was detected in the whole group. One patient had progressive deterioration of left ventricular function despite mild skeletal muscular dysfunction, and died from congestive heart failure. The cardiac dysfunction was predominant. We named it 'cardiac type' DMD. Since deterioration of cardiac function was not always correlated with deterioration of skeletal muscular function (Swinyard's stage), cardiac function must be carefully monitored in patients with DMD.

Adolescent↗
PubMed1990

The relationship between 24 hour total heart beats or ventricular arrhythmias and cardiopulmonary function in patients with Duchenne's muscular dystrophy.

To evaluate the relationship of 24 hour total heart beats (THB) or ventricular arrhythmias and cardiopulmonary function, 29 patients with Duchenne's muscular dystrophy (DMD) were studied using Holter electrocardiographic and echocardiographic recordings. The THB were 144,428 +/- 12,237 beats per 24 hours in the child group (8 to 15 years, n = 12) and 136,355 +/- 19,991 beats per 24 hours in the adult group (16 to 25 years, n = 17). The THB in the adult group significantly correlated well with % VC (r = -0.74), PaCO2 (r = 0.67), PaO2 (r = -0.59) and the respiration rate (r = 0.71), but not in the child group. In both groups, the echocardiographic parameters of the left ventricular size and function (left ventricular dimension, ejection fraction and D/S ratio) did not significantly correlate with the THB. Premature ventricular contractions (PVCs) were observed in 14 of the 29 patients (48.3%), and high risk PVCs (Lown's grade 3-4b) were observed in 11 of these 14 patients (78.6%). Echocardiographic parameters of the left ventricular function in the high risk PVC group were significantly deteriorated as compared with the low risk PVC group (Lown's grade 0-2) (p less than 0.02-p less than 0.001). We conclude that the THB in the adult group was mainly related to depressed pulmonary function, and the severity of the PVCs in both the adult and child groups was mainly related to the degree of left ventricular dysfunction.

Adolescent↗
PubMed1990

[The relationship of osteoporosis to mitral annular and aortic valvular calcification in elderly women].

Mitral annular calcification (MAC) and aortic valve calcification (AVC) are thought to be attributable to the aging process, and their incidences are especially high in elderly women. It is known that the incidence of osteoporosis (OP) is also relatively high in elderly women. Therefore, we investigated the relationship of OP to MAC and AVC. The study subjects were 39 women aged 70-89 years. MAC and AVC were investigated by echocardiography. The amount of bone mineral (BM) in the lumbar vertebral bone was measured by computed tomography using a bone phantom and the standard amount of CaCO3. MAC and AVC were detected in 14 (35.9%) and 19 (48.7%) of the 39 subjects, respectively, and there was a tendency of coexistence of MAC and AVC. There was no significant age difference between patients with and without MAC. The amount of BM was significantly lower in patients with MAC than in patients without it (27.1 +/- 8.2 vs 53.5 +/- 27.3 mg/cm3: p less than 0.01). There was no correlation between the amounts of BM and AVC. In conclusion, the amount of BM is clearly lower in elderly women with MAC, suggesting that MAC may be related to OP etiologically. However, there was no clear relationship between AVC and OP. Thus, the etiologies of AVC and MAC may be different.

Aged↗
PubMed1990

Development and sexual maturation of Taenia crassiceps (Cestoda) in the golden hamster.

The development of cysticerci of Taenia crassiceps to mature tapeworms in the intestinal tract of cortisone-treated and untreated golden hamsters is described. The development of the worms in untreated hamsters is as follows. Maturation and branching of the uterus and the presence of ova in the uterus were observed on day 15 postinfection (PI). By day 21 PI, fertilization had taken place, as evidenced by the presence of sperm in the seminal receptacle. On day 28 PI, shelled eggs were observed in feces. The rate of development of the worms in cortisone-treated hamsters was similar to that observed in untreated hamsters. More worm recovery and a longer period of worm survival were seen in the cortisone-treated than in the untreated hamsters. Thus, both cortisone-treated and untreated golden hamsters can produce normal gravid individuals of T. crassiceps.

Animals↗
PubMed1989

Purification and some properties of a Vero toxin from a human strain of Escherichia coli that is immunologically related to Shiga-like toxin II (VT2).

A cytotoxin to Vero cells (Vero toxin), which was immunologically related to Shiga-like toxin II (SLT-II) (or VT2), was purified from a stain of Escherichia coli isolated from a patient with hemolytic uremic syndrome. The toxin was active on Vero cells but much less active on HeLa cells, a property similar to that of the recently identified SLT-II variant from E. coli strains that caused edema disease of swine. Thus the toxin purified in this report was tentatively named Shiga-like toxin II variant (Vero toxin 2 variant). The purification procedures consisted of ammonium sulfate fractionation, DEAE-Sepharose CL-6B column chromatography, chromatofocusing column chromatography, and repeated high performance liquid chromatography (HPLC) on TSK-gel G-2000SW column and on TSK-gel DEAE-5PW columns. About 90 micrograms of purified toxin was obtained from 451 of the culture supernatant with a yield of about 16%. The purified toxin consisted of A and B subunits of molecular sizes similar to those of SLT-II (VT2). The isoelectric point of the purified toxin was 6.1, which was different from that of SLT-II (VT2) (pI = 4.1). In an Ouchterlony double gel diffusion test, purified toxin and SLT-II (VT2) formed precipitin lines with spur formation against anti-purified toxin and anti-SLT-II (anti-VT2), respectively. The purified toxin was cytotoxic to Vero cells, about 6 pg of the toxin killing 50% of the Vero cells, and showed lethal toxicity to mice when injected intraperitoneally, the LD50 being about 2.7 ng per mouse.

Bacterial Toxins↗
PubMed1989

[Bacteriological investigation on an outbreak of acute enteritis associated with verotoxin-producing Escherichia coli O111:H-].

An outbreak of acute enteritis in children aged one to thirty-three months occurred from June 10th to 23rd, 1986, at a private orphanage in Matsuyama City. Twenty-two out of 23 children suffered from diarrhea. Nine of the 22 children excreted bloody stool. Fever and vomiting were observed with a few patients. One of them, a 33-month-old girl, developed hemolytic uremic syndrome, and died twelve days after the admission. Escherichia coli O111:H- was isolated from fecal specimens of 7 out of 15 patients. The culture filtrate of the isolate caused fluid accumulation in ligated ileal loops in a rabbit, and was lethal to mice. It was found that all isolates produced two kinds of Vero toxins (VT1 and VT2, or shiga-like toxin I and II). The amount of VT2 produced in vitro was about 10 times more than that of VT1.

Acute Disease↗