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Biomedical subjects

Osamu Sasaki

Publications and source records attributed to Osamu Sasaki.

At least 19 recordsLinked to original sources
PubMed2006

Applicability of a progesterone-based timed artificilal insemination protocol after follicular fluid aspiration using the ovum pick-up technique in suckled beef cows.

We conducted a progesterone-based timed AI protocol after follicular fluid aspiration using the ovum pick-up (OPU) technique to examine its applicability to the suckled beef cow. A total of 19 beef cows were randomly allocated to one of the following three groups based on the number of days postpartum: 13 to 60 days (Group A: suckled; early postpartum period, n=9), 61 to 150 days (Group B: suckled; mid postpartum period, n=6), or 151 to 281 days (Group C: non-suckled; prolonged open period, n=4) postpartum. These cows were treated with follicular fluid aspiration and insertion of a progesterone-releasing intravaginal device (PRID) on day 0. The PRID was removed and 500 microg of cloprostenol was intramuscularly administered on day 7. A dose (100 microg) of fertirelin acetate was injected intramuscularly 48 hours later, and this was followed by a timed AI (TAI) after another 18 hours (day 10). Serum samples were taken on days 0, 7, 9, 10, 12, 17, 24 and 31 for determination of the estradiol-17beta (E(2)) and progesterone concentrations. Pregnancy diagnosis was made by rectal palpation approximately 60 days after TAI. There was no significant difference in the peripheral E(2) concentrations among the three groups during the period of the hormonal treatment. The average progesterone concentrations in Group A on day 17 were significantly higher than those in Group B and exceeded 1.0 ng/ml on day 17 and thereafter. There was no significant difference in the numbers of collected immature oocytes among the three groups. The pregnancy rates in Groups A, B, and C were 77.8% (7/9), 83.3% (5/6) and 50.0% (2/4), respectively. In conclusion, this timed AI protocol is applicable to suckled beef cows within the period of 60 days postpartum.

Administration, Intravaginal↗
PubMed2006

Positive correlations between cerebral choline and renal dysfunction in chronic renal failure.

INTRODUCTION: Cerebral metabolism in chronic renal failure (CRF) patients has not been fully evaluated. This study examined cerebral metabolites in CRF, using proton magnetic resonance spectroscopy (MRS). METHODS: Subjects comprised 19 CRF patients and 21 healthy volunteers. Spectra were acquired from voxels of interest positioned in the parietal gray and white matter, and concentrations of the following cerebral metabolites were measured: N-acetyl group (NA), creatine + phosphocreatine (Cr), choline-containing compounds (Cho), myo-inositol and glutamate + glutamine. Among the 19 CRF patients, 9 who were started on hemodialysis (HD) underwent careful follow-up. Proton MRS was performed before and about 2 weeks after starting HD. In six patients in whom follow-up was possible, a third MRS was performed after about 18 months. RESULTS: The NA/Cr ratio was not significantly changed in CRF. However, elevations in the Cho/Cr ratio were found in both gray and white matter compared with controls. To the best of our knowledge, this is the first report of positive correlations between the Cho/Cr ratio in both regions and serum osmotic pressure. Compared with baseline data, no significant changes in cerebral metabolite ratios were found about 2 weeks after starting HD. About 18 months after starting HD, however, the elevated Cho/Cr ratio was significantly reduced in the gray matter and tended to be reduced in the white matter. CONCLUSIONS: Cho appear to play an important role in the regulation of cerebral metabolism to compensate for alterations in serum osmotic pressure in CRF, and HD may correct this abnormal cerebral metabolism.

Adult↗
PubMed2006

Association of takotsubo cardiomyopathy and long QT syndrome.

A young woman presented with takotsubo cardiomyopathy after a syncopal attack caused by torsades de pointes. Two-dimensional echocardiography on admission showed left ventricular apical akinesis (ballooning) and basal hyperkinesis, compatible with takotsubo cardiomyopathy. This gradually normalized in 2 months. ECG on admission showed remarkable QT prolongation, U waves, and negative T waves, which also gradually normalized. Coronary angiography revealed no organic stenosis; however, acetylcholine provocation test caused the QT interval to again become prolonged. During treadmill exercise stress testing, the QT interval shortened as heart rate increased. Therefore, without genetic analysis, this patient was considered to have sporadic long QT syndrome in which takotsubo cardiomyopathy developed after the syncopal attack caused by torsades de pointes.

Adult↗
PubMed2005

QTc dispersion in haemodialysis patients with cardiac complications.

BACKGROUND AND AIMS: QTc dispersion (Maximum - Minimum QTc interval on a standard 12-lead electrocardiogram (ECG)) is a useful predictor of tachyarrhythmic events and related sudden cardiac death. Recent studies have reported that QTc dispersion is prolonged in patients receiving haemodialysis (HD), and it is often further prolonged following HD treatment. In the present study, we examine whether the patients who are susceptible to prolongation of QTc dispersion by HD are prone to life-threatening cardiovascular events and related deaths. METHODS: Forty-eight patients with cardiac symptoms such as chest pain (n = 32), arrhythmia (n = 2) or heart failure (n = 14) and receiving chronic HD treatment (40 males and eight females) were subjected to the present study. Twenty-six of a total 48 patients were given a diagnosis of ischaemic heart disease (IHD) by coronary angiography. Ten patients had cerebrovascular accidents and 11 patients had peripheral vascular disease. After the ECG recording, a prospective follow up was conducted for 37 +/- 24 months. RESULTS: During the follow-up period, 30 patients had cardiac events, and 23 including 18 cardiovascular deaths occurred as outcomes. Throughout the total period, patients who showed prolongation of QTc dispersion after HD had cardiovascular deaths with higher incidence than those did not show the prolongation. CONCLUSIONS: We consider that prolongation of QTc dispersion after HD treatment can predict the prognosis of patients with renal failure bearing cardiac complications. Great care is necessary for such patients if they show longer QTc dispersion and/or susceptibility for further prolongation after HD treatment.

Adult↗
PubMed2005

[Second transplant from the same donor without conditioning for bone marrow aplasia after non-myeloablative hematopoietic stem cell transplantation for chronic myeloid leukemia].

We describe a 56-year-old woman with chronic myeloid leukemia (CML) and a past history of stroke, who underwent nonmyeloablative hematopoietic stem cell transplantation (NST) with conditioning consisting of fludarabine and cyclophosphamide. The regimen related toxicity was minimal and patient did not require transfusions of any blood products nor did she have any infections after the NST Since mixed chimerism was observed in both lymphocytes (70% were donor type) and granulocytes (none were donor type) at 56 days after NST, donor lymphocyte infusion (DLI) was performed on day 68 and then immunosuppressant therapy was discontinued. DLI resulted in graft versus leukemia (GVL) effect, causing pancytopenia and bone marrow aplasia. A second hematopoietic stem cell transplantation was performed without conditioning on day 157, and complete donor type hematopoiesis and molecular remission of CML were achieved. Although engraftment of donor hematopoietic stem cells was not obtained after the first transplantation, donor lymphocytes were engrafted by nonmyeloablative conditioning and immunosuppression. That is, the same result might have been achieved even if the patient had received transfusion of only donor lymphocyte subsets in the first step. Based on this case report, a potential cell therapy is proposed composed of the preceding donor lymphocyte infusion alone, which induces GVL effects, and subsequent donor hematopoietic stem cell transplantation.

Bone Marrow Diseases↗
PubMed2004

Orthostatic hypotension at the introductory phase of haemodialysis predicts all-cause mortality.

BACKGROUND: Since the predictive value of orthostatic hypotension (OH) at the introductory phase of haemodialysis (HD) is unknown, we examined the association between OH and all-cause death in patients who started HD between 1987 and 2001. METHODS: More than three consecutive blood pressure measurements before HD treatments (pre-HD BP) were made on each of 304 patients who had recently been started on HD and were in a stable condition. OH was defined as a drop in systolic BP of >20 mmHg or in diastolic BP of >10 mmHg after standing. RESULTS: Of 304 patients, 42% had OH. OH was significantly associated with pre-HD supine systolic BP; its severity was significantly associated with a past history of cerebrovascular disease and pre-HD supine systolic BP. During a mean follow-up of 4.0+/-3.0 years (range 0.1-13.2 years), 136 deaths were recorded. A multivariate Cox proportional hazards model analysis demonstrated that OH and a past history of cerebrovascular disease were independent predictors of all-cause death. The comparison by Kaplan-Meier analysis of the overall survival of patients with and without OH was significant. CONCLUSIONS: Our findings validate OH at the introductory phase of HD as a novel independent predictor of all-cause mortality among HD patients.

Aged↗
PubMed2004

[A case of foxhole-shaped left ventricular abnormality induced by complete atrioventricular block with delayed recovery of wall motion].

An 86-year-old woman suffered sudden onset chest discomfort and dyspnea during sleep in the early morning of August 1, 2003. On admission, electrocardiography demonstrated complete atrioventricular block. Echocardiography showed severe hypokinesis in the left ventricular apex and hyperkinesis at the base. Serum cardiac deviant enzymes were slightly elevated. Based on these findings, acute myocardial infarction accompanied by complete atrioventricular block was suspected. Emergency coronary angiography performed under temporary pacing showed no significant stenosis in the coronary arteries. However, ventriculography demonstrated the presence of a foxhole-shaped left ventricular abnormality. A VDD type permanent pacemaker was implanted 5 days after the onset of the symptoms because the atrioventricular block had not improved. Following the implantation, pleural effusion and a temporary elevation of the body temperature occurred. The myocardial scintigraphy using 123I-metaiodobenzylguanidine (123I-MIBG) in the acute phase demonstrated extensive cardiac sympathetic nerve damage in the left ventricular apex. This condition was managed by medication including diuretics, angiotensin II receptor blocker and beta-blocker. Three months later, echocardiography and 123I-MIBG myocardial scintigraphy showed slight recovery of wall motion and sympathetic activity. However, mild pleural effusion persisted. A complete atrioventricular block was also present at this stage. In view of these findings, this case suggested that the foxhole-shaped left ventricular abnormality induced complete atrioventricular block with delayed recovery of wall motion.

Aged↗
PubMed2003

Periodic alternating nystagmus and rebound nystagmus in spinocerebellar ataxia type 6.

We report on a family with ataxia type 6 (SCA6) showing peculiar oculomotor symptoms. The proband presented with periodic alternating nystagmus (PAN), and her 2 brothers had rebound nystagmus and gaze-evoked nystagmus. They carried the identical mutation (the number of expanded CAG repeat, 24) in the CACNA1A gene. The intrafamilial variability of oculomotor symptoms may be ascribed to factors other than CAG repeat expansion size in SCA6.

Calcium Channels↗
PubMed2003

Microalbuminuria and cardiovascular events in elderly hypertensive patients without previous cardiovascular complications.

To assist in the development of better treatments for elderly hypertensive patients, we studied the degree to which the baseline values of urinary albumin excretion (UAE) and other cardiovascular risk factors were predictive of cardiovascular complications in a cohort of elderly hypertensive patients. In 1994, we adopted 144 elderly hypertensive patients, who had been treated for more than 6 years at various clinics and more than 1 year at the National Cardiovascular Center, Osaka, Japan. They were divided into 2 groups: a NA group (n=111) with normoalbuminuria (UAE<30mg/day) and an MA group (n=33) with microalbuminuria (UAE 30-300 mg/day). At baseline, the two groups were similar with respect to systolic and diastolic blood pressure (SBP/DBP), pulse pressure (PP), age, ratio of males to females, serum creatinine, uric acid, total cholesterol, fasting plasma glucose (FPG), and creatinine clearance (CCr). PP was calculated as SBP minus DBP. The efficacy of blood pressure (BP) control was similar in both groups during the 8-year follow up period; however, a total of 14 cardiovascular events occurred in the MA (6/33) and NA (8/111) groups, with the MA group showing the higher incidence rate by multiple logistic regression analysis (p<0.05). At 8 years of follow-up, PP and age were correlated with UAE (p<0.05, p<0.001). At the same time point, CCr was correlated with UAE at baseline (p<0.05). The results indicated that, in elderly hypertensive patients without previous cardiovascular complications, microalbuminuria can be a predictor of cardiovascular events irrespective of conventional BP control.

Aged↗
PubMed2003

Protective effect of Pasteurella multocida cell-free antigen and toxoid against challenge with toxigenic strains of pasteurella multocida in mice.

The cell-free antigen (CFA) obtained from the culture supernatant of Pasteurella multocida (P. multocida) and the toxin (PMT) purified from CFA were inactivated and mixed with oil adjuvant to prepare a trial vaccine. Both of the mice immunized with CFA and PMT toxoid vaccine were noticeably protected against intratracheal challenge with toxigenic strains of P. multocida. Nevertheless, the protective indices of the mice immunized with CFA vaccine indicate that it is more protective and clears away the bacteria more promptly than in the mice immunized with PMT vaccine. The results suggested that CFA would possibly be good as an effective antigen to toxigenic strains of P. multocida infection.

Animals↗
PubMed2002

Role of visual input in nonlinear postural control system.

Stabilometry signals involve irregular and unpredictable components. The purpose of the present study was to investigate these signals with a nonlinear technique to examine how the complexity of the postural control system breaks down under altered visual conditions. We evaluated the dynamical similarities of the postural control system when the eyes were open or closed, or when there was optokinetic stimulation (OKS). A similarity index was calculated by the cross-correlation integral between the two dynamics: eyes open and eyes closed, or eyes open with OKS. Using this technique, dynamical changes were not observed between eyes-open and eyes-closed conditions. This result suggests that the nonvision condition does not produce any striking effect on the postural control system; instead, the eyes-open condition causes a decrease in the stochastic activity of the postural control system, which may originate mainly from the stiffness of the musculoskeletal systems. In contrast, the visual input of OKS affected the dynamics of the postural control system in nearly half of the subjects (group 2) despite showing no significant differences between the eyes-open condition and the other conditions for area as the conventional parameter. However, the other half of the subjects (group 1) did not experience any influence of OKS on their postural dynamics, despite showing significant differences between eyes-open and the other conditions for all traditional parameters. From the results for group 2, we hypothesize that OKS may induce the striking effect on dynamics properties of the multilink network system involving visual and vestibular cortex related to self-motion perception, which acts to decrease the stochastic activity in order to correct disturbed posture.

Adult↗
PubMed2002

Primary marginal zone lymphoma of the thymus accompanied by chromosomal anomaly 46,X,dup(X)(p11p22).

We report a case of primary marginal zone lymphoma in the thymus of a 34-year-old woman. She was initially suspected of having a mediastinal plasmacytoma because of the presence of dominantly proliferating plasmacytic cells in a small fragment obtained by thoracoscopic biopsy, and an elevated level of serum monoclonal IgA. However, histology of the tissue obtained by a subsequent open surgical biopsy revealed diffuse proliferation of atypical monocytoid B-lymphocyte-like cells, which showed prominent plasmacytic differentiation and a close association with thymic epithelial cells consistent with the histology of a marginal zone lymphoma of the thymus. These lymphoma cells were positive for CD19, CD20, IgA, and kappa, and negative for CD5, CD10, and other T/NK-cell and myelomonocyte antigens. Both G-banded and spectral karyotyping analyses revealed the lymphoma cells carried a chromosomal anomaly, 46,X,dup(X)(p11p22). Although large cell type B-cell lymphoma in the thymus (mediastinal diffuse large B-cell lymphoma), which is categorized as a definite subtype in revised European-American classification of lymphoid neoplasms and the new World Health Organization classification, is not infrequent, primary marginal zone lymphoma of the thymus is extremely rare. To our knowledge, this is the first case report of primary marginal zone lymphoma of the thymus with a detailed chromosomal analysis.

Adult↗
PubMed2002

Altered expression of retinoblastoma protein-interacting zinc finger gene, RIZ, in human leukaemia.

The retinoblastoma protein-interacting zinc finger gene (RIZ), a member of the nuclear protein methyltransferase superfamily, is characterized by the presence of the N-terminal PR domain. The RIZ gene encodes for two proteins, RIZ1 and RIZ2. While RIZ1 contains the PR (PRDI-BF1 and RIZ homologous) domain, RIZ2 lacks it. RIZ gene expression is altered in a variety of human cancers and RIZ1 is now considered to be a candidate tumour suppressor. To investigate the role of RIZ in leukaemogenesis, we analysed the differential expression of RIZ1 and RIZ2 by quantitative real-time reverse-transcription polymerase chain reaction assay. Our results showed that the expression of RIZ1 was significantly decreased in leukaemia cell lines (14 out of 17, 82%) and in patients with acute myeloblastic leukaemia (eight out of 14, 57%). In contrast, RIZ2 expression was increased in patients with acute lymphoblastic leukaemia (eight out of 11, 73%), compared with normal bone marrow cells. These findings indicate that suppression of RIZ1 expression or enhancement of RIZ2 expression may have an important role in leukaemogenesis.

Adolescent↗
PubMed2002

Left ventricular hypertrophy is a risk factor independent of hypertension in survival of hemodialyzed patients.

Hemodialysis patients have low 5-year survival rates of approximately 60%, and the most common cause of death is cardiovascular diseases. Their population may be considered, therefore, as an accelerated model in analyzing the risk factors for cardiovascular diseases. We previously reported the role of blood pressure, one of the most important risk factors for cardiovascular diseases, in determining the prognosis of hemodialysis patients. In this study, we examined the effect of cardiomegaly detected on chest roentgenogram or electrocardiogram before initiating hemodialysis therapy on survival after introduction to maintenance hemodialysis. One hundred and sixty hemodialysis patients who had no history of ischemic heart disease or arrhythmia were followed up for 88.9 +/- 4.0 months, among whom 69 died. Heart enlargement, defined on chest roentgenogram, was detected in 104 patients, and left ventricular hypertrophy, defined on electrocardiogram, was detected in 105 patients. The presence of either finding shortened their survival. However, Cox's proportional hazards model and logistic multiple regression analysis identified only left ventricular hypertrophy as one of the significant determinants for survival, but heart enlargement was not independent. Correction of systolic hypertension on the maintenance phase had no significant favorable effect on survival in patients with left ventricular hypertrophy, while it improved in those with heart enlargement. This finding, together with those above from Cox's model and logistic analysis strongly suggests that risk from left ventricular hypertrophy is independent of, but one from heart enlargement is dependent on hypertension.

Cardiovascular Diseases↗
PubMed2002

Ocular surface inflammation induced by Propionibacterium acnes.

PURPOSE: In the eye, is commonly isolated in the lid, conjunctiva, and meibomian gland secretion. Well known as a causative bacterium of granulomatous endophthalmitis and a potent inflammatory stimulus, reportedly induces a delayed-type hypersensitivity (DTH) response and forms granulomas in the liver and lung in animal models. In this study, we examined whether can induce a DTH response in the cornea. METHODS: Six- to 8-week-old female Lewis rats were immunized with heat-killed suspension of and assessed as to DTH response via ear challenge at 2 weeks after immunization. At 3 weeks after immunization, suspension was injected in the rat corneal stroma, which was then observed biomicroscopically at 6, 24, and 48 hours after injection. Phenol-killed suspension was also used for the comparison. Histological examination was also performed on the corneal tissues, using hematoxylin and eosin staining as well as immunohistochemical staining against CD4 and CD8 T cells. RESULTS: Rats immunized with suspension showed significantly higher ear swelling values at both the 24- and 48-hour measurements than did the naïve controls (p < 0.005). Massive cellular infiltration with stromal edema was observed biomicroscopically at 48 hours after injection of suspension in the corneal stroma. Histological study showed that the cell infiltration pattern was similar to that of DTH in the skin, i.e., neutrophils infiltrated at 6 hours, followed by mononuclear cells that, including macrophages and lymphocytes, increased and mixed with neutrophils, accompanied by stromal edema at 48 hours. Immunohistochemical study revealed that CD4 T-cell infiltration in the corneal stroma appeared to predominate over CD8 T-cell infiltration. CONCLUSIONS: These results indicate that can induce a DTH response in the cornea and may be a causative bacterium of ocular surface inflammation.

Animals↗