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Biomedical subjects

S Sakamoto

Publications and source records attributed to S Sakamoto.

At least 523 records · Page 29Linked to original sources
PubMed1989

Development of an ultrasonic system for three-dimensional reconstruction of the fetus.

The ultrasonic diagnostic devices available at present can only represent one section of the fetus. We have developed a system for three-dimensional reconstruction of the ultrasonic fetal image in order to facilitate the understanding of the 3-D structure of the fetus and also to make 3-D recordings of this image. Either a real-time linear array probe or a convex array probe of the ultrasonic scanner was mounted on a position sensing arm of a manual compound scanner in order to detect the position of the probe. A microcomputer was used to convert the positional information to a recording of a visual image of videotape. This image was superimposed onto the ultrasonic tomographic image simultaneously using a superimposer and was recorded on the video tape, thereafter, being recalled by the image processing minicomputer. The minicomputer VAX11/780 (DEC) system was used for 3-D reconstruction and 3-D display. In the memory system the image of the anterior uterine wall was identified and subsequently excluded in order to visualise the fetus more clearly. The threshold of brightness was set to a high level so that the fetus could be separated from the amniotic fluid. The fetus was displayed three-dimensionally using computer graphics. Using this system, we have made it possible to observe the whole image of the fetus in utero non-invasively. This system offers a method for easier understanding of the 3-D structure of the fetus in utero and also makes 3-D recording possible. In the future, we confidently expect that this system will be used for screening for fetal anomalies and abnormalities of fetal growth.

Equipment Design↗
PubMed1989

Clinical significance of exercise-induced negative U-waves in patients with anterior myocardial infarction.

To elucidate the clinical significance of the exercise-induced negative U-wave (NU) in patients with anterior myocardial infarction, we compared the angiographic and scintigraphic findings in 15 patients with and 20 patients without NU, and obtained the following results: 1) On coronary angiography, all patients in the NU (+) group showed over 90% stenosis or total occlusion of the left anterior descending coronary artery (LAD). In the latter cases moderate to abundant collaterals were visualized on the anterior wall. In contrast, such a tendency was not observed in the NU (-) group. 2) Segments composed of viable myocardium (estimated by preservation of contraction at rest and T1-201 redistribution after exercise) numbered 30 of 45 segments (67%) in the NU (+) group, and 13 of 60 segments (22%) in the NU (-) group. Segments composed of lost myocardium (estimated by loss of contraction at rest and persistent defect in T1-201 uptake) numbered 7 of 45 segments (16%) in the NU (+) group, and 38 of 60 segments (63%) in the NU (-) group. 3) Exercise-induced NU was frequently observed on R-wave preserved leads with ST depression, but was also observed over abnormal Q waves, ST elevation and in isolation in some instances. 4) In 3 patients, preexisting exercise-induced NU was no longer observed and a transient stress-induced T1-201 defect disappeared after successful LAD revascularization. In conclusion, exercise-induced NU on precordial leads in patients with anterior myocardial infarction may be a sign suggesting the presence of jeopardized, but still salvageable, myocardium in the infarcted area.

Aged↗
PubMed1989

Bronchoconstrictive properties and potentiating effect on bronchial responsiveness of inhaled thromboxane A2 analogue (STA2) in guinea pigs.

Effect of subthreshold concentration of inhaled STA2, a thromboxane A2 (TXA2) analogue, on bronchial responsiveness to histamine was investigated in anesthetized and artificially ventilated guinea pigs. Percent increase in pressure of the airway opening (Pao) by aerosol histamine (50, 100 micrograms/ml) was significantly potentiated by subthreshold dose of aerosol STA2 (0.10 micrograms/ml) which was determined by dose-response curve of % increase in Pao by inhaled STA2 (0.033, 0.10, 0.33, 1.0 micrograms/ml). These results demonstrated that thromboxane A2 could contribute to bronchial hyperresponsiveness which is one of the major clinical features of bronchial asthma.

Aerosols↗
PubMed1989

Matrix collagen of devitalized bone is resistant to osteoclastic bone resorption.

The resorption of devitalized bone by isolated osteoclasts in culture was studied by scanning electron microscopy. Osteoclasts attached to the bone and resorbed mineral but left most of matrix collagen undigested in the resorption pits. Postculture-treatment of bone substrate with collagenase completely removed the matrix collagen in the resorption pits, whereas trypsin did not. The results suggest that native matrix collagen is resistant to osteoclastic attack in this in vitro model using devitalized bone.

Animals↗
PubMed1989

[Cerebral hemodynamics in multiple cerebral infarction with or without dementia].

Cerebral blood flow and metabolism in 25 patients with multiple cerebral infarcts (14 with dementia) and 5 healthy age-matched controls were measured to investigate the difference in cerebral blood low (CBF) and cerebral oxygen consumption (CMRO2) between patients with dementia and patients without dementia. None of the patients had any lesions in the cortex, but all had multiple lesions in the basal ganglionic region, and in the white matter, according to CT images. CBF, CMRO2 and oxygen extraction fraction were measured by positron emission tomography (PET) using the 15O2, C15O2 steady state inhalational technique. In patients with multiple cerebral infarcts the absolute values of CBF and CMRO2 were decreased significantly from normal control values, and there was no significant difference in the absolute values of CBF and CMRO2 between patients with dementia and patients without dementia. In most patients with dementia, relative values (regional value/mean cortical value) of CBF and CMRO2 decreased in the frontal and the parietal cortex. Four patients had repeated PET studies. In two of them, decrease in CMRO2 was preceded by decrease in CBF. These results suggest that dysfunction of frontal cortex and parietal cortex, and chronic ischemia might be related to the occurrence of dementia in patients with multiple cerebral infarcts, which were in the basal ganglia and the white matter.

Aged↗
PubMed1989

[Lung metastases of prostatic cancer vanished by early combined hormonal and chemotherapy: report of a case].

A 69-year-old man initially came to our hospital with the chief complaint of dysuria and hematuria. On rectal examination, the prostate gland was found to be grossly enlarged and rock hard in consistency. Abnormal laboratory data included: lactate dehydrogenase, alkaline phosphatase, acid phosphatase and prostatic acid phosphatase. Chest X-ray revealed multiple nodular lesions in both lung fields. Pathologic findings of the prostate needle biopsy revealed moderately well differentiated adenocarcinoma. Early combined hormonal and chemotherapy (adriamycin, TGF, methotrexate, bleomycin) was performed. After two courses of this regimen, the pulmonary lesions vanished completely. In addition, partial disappearance of osteoblastic lesions on bone scans was recognized.

Adenocarcinoma↗
PubMed1989

In vivo activation of human neutrophil functions by administration of recombinant human granulocyte colony-stimulating factor in patients with malignant lymphoma.

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) was administered (50 to 800 micrograms/m2) once daily as a half-hour intravenous (IV) infusion for 14 days to seven patients with malignant lymphoma. In all patients, administration of rhG-CSF not only ameliorated the decrease in absolute neutrophil count after the cytotoxic chemotherapy but also enhanced superoxide (O2-) release in neutrophils stimulated by N-formyl-methionyl-leucyl-phenylalanine (FMLP). The priming effect of rhG-CSF on neutrophil O2- release was rapid (evident within 6.5 hours) and sustained at least for 24 hours after a single IV administration of rhG-CSF. The responsiveness to further in vitro challenge of rhG-CSF was lost or reduced in neutrophils isolated after rhG-CSF treatment, indicating that neutrophils already primed in vivo by rhG-CSF are desensitized to this factor. In contrast to the results obtained with FMLP, when phorbol myristate acetate (PMA) was used as stimulus, no consistent enhancement of O2- release was observed, suggesting that rhG-CSF modulates the signal transduction pathways linked to FMLP receptors rather than increases the components of the O2- producing enzyme complexes. Administration of rhG-CSF also rapidly (evident within 15 minutes) caused an increase in expression of neutrophil C3bi-receptors that was sustained for at least 24 hours after a single IV administration of rhG-CSF. Pharmacokinetic study of rhG-CSF showed a half-life (t1/2) of 114 min. These findings show that rhG-CSF is a potent activator for neutrophil functions both in vivo and in vitro.

Aged↗
PubMed1989

[Left ventricular diastolic flow dynamics in dilated cardiomyopathy: a color flow imaging and pulsed Doppler echocardiographic study].

Left ventricular filling flow was evaluated at the mitral orifice and in the left ventricle (LV) using color flow imaging and pulsed Doppler echocardiography in seven patients with dilated cardiomyopathy (DCM) and 10 normal subjects. Using the apical approach, filling flow in early and late diastole was observed by two-dimensional color and M-mode color flow imaging, and flow velocity patterns at the mitral orifice and in the LV, 3 cm below the orifice, were analyzed by pulsed Doppler echocardiography. Color flow imaging disclosed slower movement of the inflow signals toward the apex in DCM than in the normal. With pulsed Doppler echocardiography, the delay in timing of peak velocity in the LV was distinctly greater in DCM than in the normal, although the mitral inflow velocity did not differ between DCM and the normal. The width of the filling flow, the rate of velocity reduction and the flow velocity in the LV did not differ between DCM and the normal. Thus, in DCM, the timing of filling flow in the LV is clearly delayed compared to the timing at the mitral orifice, and this cannot be explained solely by the mitral flow velocity pattern.

Adult↗
PubMed1989

[The role of cyclooxygenase products on bronchial responsiveness to methacholine in patients with sino-bronchial syndrome].

The role of cyclooxygenase products on bronchial responsiveness to methacholine was studies in 9 patients with sino-bronchial syndrome. Provocative concentrations of methacholine, producing a 20% fall in forced expiratory volume in one second (FEV1)(PC20-FEV1) and a 35% fall in inverse respiratory resistance (Grs) (PC35-Grs), were measured before and after oral administration of a thromboxane synthetase inhibitor (OKY-046) and a cyclooxygenase inhibitor (indomethacin). Baseline values of FEV1 and respiratory resistance (Rrs) were not altered by OKY-046 or indomethacin. Geometric mean values of PC20-FEV1 and PC35-Grs were significantly (p less than 0.005 and p less than 0.05) increased from 2.19 mg/ml (GSEM, 1.58) and 0.79 mg/ml (GSEM, 1.70) to 8.13 mg/ml (GSEM, 1.92) and 1.55 mg/ml (GSEM, 1.38) by indomethacin, whereas these values were not significantly increased by OKY-046. These findings indicate that not thromboxane A2 but bronchoconstricting prostaglandins may play a role in bronchial hyperresponsiveness in sino-bronchial syndrome.

Bronchi↗
PubMed1989

[Germ-line configuration of the immunoglobulin heavy chain gene in a case of B cell precursor acute lymphoblastic leukemia].

A 20-year-old man was admitted to our hospital because of fever and knee joint pain on March 20, 1986. Physical examination revealed generalized lymphadenopathy and hepatomegaly. White blood cell count was 32,800 microliters with 74.4% blast cells. Bone marrow was hypercellular with 93.6% blast cells. Blast cells were weakly positive for acid phosphatase and PAS stainings but were negative for peroxidase, sudan black B and esterase stainings. Cell surface marker analysis of blast cells disclosed that they were positive for anti-HLA-DR, CD19, CD24, CD33 and CD38, but were negative for CD10 and CD20. Cytoplasmic immunoglobulin of blast cells was negative and TdT activity by immunofluorescent method was positive. Chromosomal analysis of bone marrow samples revealed normal karyotype. Therefore, this case was diagnosed as having acute lymphoblastic leukemia (L2) and achieved complete remission with LVP therapy consisting of 1-asparaginase, vincristine and prednisolone. Gene analysis of blast cells disclosed germ-line configuration of both the immunoglobulin heavy chain gene and T cell receptor beta chain gene. We speculated that the phenotype of leukemic cells might precede the genotype in some cases of acute leukemia.

Acute Disease↗
PubMed1989

[Inhibitory effect of procaterol (beta 2 agonist) on the release of cyclooxygenase products during antigen-induced bronchoconstriction in the guinea pig in vivo].

The purpose of this study was to investigate whether procaterol (beta 2 agonist) inhibits the release of cyclooxygenase products in bronchoalveolar lavage fluid (BALF) during in vivo allergic bronchoconstriction in passively sensitized guinea pigs. Antigen-induced bronchoconstriction was significantly inhibited by pretreatment with procaterol. The concentrations of 6-keto-PGF1 alpha, PGF2 alpha and TXB2 in BALF significantly decreased in guinea pigs pretreated with inhaled procaterol. The concentration of TXB2, which is the stable metabolite of TXA2, a strong bronchoconstrictor, was especially markedly decreased compared with that in the control animals. These data indicate that procaterol (beta 2 agonist) may inhibit the release of chemical mediators during allergic reactions as well as directly decrease the contractility of airway smooth muscle. Consequently, regular inhalation of procaterol may be clinically useful for prophylaxis of bronchial asthma.

Administration, Inhalation↗
PubMed1989

[Multivariate analysis of prognostic factors influencing survival in chronic myelogenous leukemia].

Prognostic significance of disease features obtained at the time of initial diagnosis was analyzed in 90 patients with chronic myelogenous leukemia (CML) in chronic phase. Median survival of this population was 45.9 months. Univariate analysis revealed that splenomegaly, bone marrow basophils, bone marrow blasts, peripheral blood blasts, and bone marrow eosinophils were significant prognostic factors for survival, and that peripheral blood leukocytes counts, hemoglobin concentration, performance status, age and lymphadenopathy were factors with border line significance. There were multiple interrelationship among these disease features. Multivariate regression analysis identified that age, hemoglobin concentration, and bone marrow blasts were independent primarily significant prognostic factors for survival. The Cox model generated with three variables of age, hemoglobin concentration, and percent blasts in bone marrow provided a useful representation of risk status in the population. A hazard function derived from the patients population segregated patients into three groups with significantly different survival patterns: A lower risk group, an intermediate group and a high risk group of patients with median survival of 57.8, 49.8 and 38.4 months respectively. Survival after CML blast crisis was short and overall median survival of 54 patients with CML blast crisis was 6.4 months. A sole prognostic factor for survival in blast crisis identified by multivariate analysis was blast cell type at CML blast crisis and patients with lymphoid phenotype had a good prognosis with median survival of 9.8 months. Median survival of myeloid crisis was 4.2 months. No other disease features were identified as significant prognostic factors in the present patient population.

Adult↗