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Biomedical subjects

S Ishikawa

Publications and source records attributed to S Ishikawa.

At least 127 records · Page 7Linked to original sources
PubMed2000

Muscle CT scan findings in McLeod syndrome and chorea-acanthocytosis.

Computed tomography (CT) scans of lower leg muscles reveal a selective pattern of fat infiltration in the posterior compartment with spared gracilis, semitendinosus, and the lateral head of the gastrocnemius in both McLeod syndrome and chorea-acanthocytosis, which are disorders characterized by the presence of circulating acanthocytes. The selectivity of affected muscles indicates that late onset and slowly progressive muscular atrophy in both diseases could be a consequence of primary myopathy. Asymmetrical muscle involvement may be seen during the process of degeneration only in McLeod syndrome, however, and may be helpful in distinguishing this disease from chorea-acanthocytosis.

Adult↗
PubMed2000

A new model of lung metastasis for intravital studies.

We created anexperimental model of pulmonary metastasis based on subcutaneously implanted Lewis lung cancer in mice and observed in vivo the microcirculation of spontaneously metastasized tumors in the lung. The mice lung was held by a small handmade suction ring to stop cardiac and respiratory movement. Using fluorescent microscopy, tumor microcirculation and normal lung microcirculation in the same lung lobe were compared by measuring microvessel diameter and blood flow velocity [red blood cell (rbc) velocity]. In normal microcirculation, the mean values of microvessel diameter and rbc velocity were 10.4 +/- 2.7 microm and 188 +/- 63 microm/s, respectively. In tumor microcirculation, the mean values of the same were 10.6 +/- 3.3 microm and 105 +/- 40 microm/s. The rbc velocity in normal microcirculation was significantly higher (P < 0.001) than that in tumor microcirculation. The calculated shear rates of normal microcirculation and tumor microcirculation were 73.4 +/- 23.4 (/s) and 41.2 +/- 16.1 (/s), respectively. The shear rate of the tumor microcirculation was significantly slower (P < 0.001) than that of the normal microcirculation. We demonstrated a feasibility of observation and measurement of tumor microcirculation in the lung and confirmed that the physiologic data were compatible to those in the brain or in the liver reported by others. This model might be useful for studying metastatic tumor pathophysiology in the lung microcirculation.

Animals↗
PubMed2000

Accuracy of carboxyhemoglobin dilution method for the measurement of circulating blood volume.

PURPOSE: The management of circulating blood volume (BVc) is crucial in intensive care unit (ICU) patients. The purpose of this study was to verify the accuracy and precision of the carbon monoxide-labeled hemoglobin (CO-Hb) dilution method (CO method) by comparing it with the 51Cr-labeled erythrocyte dilution method (51Cr method) for the measurement of BVc. METHODS: A prospective study was performed in 18 patients who underwent coronary artery bypass grafting (CABG) under mild hypothermic cardiopulmonary bypass (CPB). The BVc was measured by both the CO method and the 51Cr method at 24 hr after ICU admission in order to verify the accuracy and precision of the CO method. Paired data were assessed in absolute terms, and percentage errors were calculated by the degree of agreement. RESULTS: Small mean differences and standard deviations between the CO method and the 51Cr method (-70.2 +/-184.8 mL) and small percentage errors (-0.49+/-1.29%) indicated the accuracy and precision of the CO method, and a close correlation was observed (r = 0.97). CONCLUSION: The CO method can measure BVc with a similar degree of accuracy as the 51Cr method. It is simple, repeatable and safe without the risk of exposure to radioactivity in the ICU.

Blood Volume↗
PubMed2000

Changes in gastric intramucosal pH and circulating blood volume following coronary artery bypass grafting.

PURPOSE: To determine the changes in gastric intramucosal pH (pHi) following coronary artery bypass grafting (CABG) in comparison with systemic hemodynamic variables and circulating blood volume (BVc). METHODS: Twenty patients who underwent CABG under mild hypothermic cardiopulmonary bypass (CPB) were included. Hemodynamic variables and the values of pHi were obtained at 3,6, 12 and 24 hr after admission to the intensive care unit (ICU). The pHi was measured by gastric tonometric catheter. The BVc was measured by carbon monoxide (CO)-labeled hemoglobin (CO-Hb) dilution method (CO method) at 6 and 24 hr after ICU admission. RESULTS: Systemic vascular resistance index (SVRI) and pulmonary vascular resistance index (PVRI) decreased with time. Systemic oxygen delivery index (DO2I) and systemic oxygen consumption index (VO2I) showed a gradual increase during the study period. By contrast, pHi decreased to the lowest value (7.26+/-0.05) at six hours and returned to normal levels (7.34+/-0.04) at 24 hr after ICU admission. Changes in BVc between six and 24 hr ranged from -242 ml to 978 ml (mean, 334+/-338 ml). The pHi increased in patients whose BVc increased by > 300 ml. Mean fluid balance was negative in this period (-386+/-667 ml; range, -1786 - + 423 ml). CONCLUSION: The pHi showed the lowest value at six hours and returned to normal at 24 hr after ICU admission. The pHi increased with the decrease in vascular resistance and with the increases in BVc in this period. The improvement of pHi, an indicator of splanchnic perfusion, appears to be related to systemic vasodilatation and an increase in BVc.

Aged↗
PubMed2000

Uptake and elimination of sevoflurane in rabbit tissues--an in vivo magnetic resonance spectroscopy study.

PURPOSE: Previous pharmacokinetic studies of fluorinated anesthetics using 19F-magnetic resonance spectroscopy (19F-MRS) have focused on the brain. Investigation of other tissues would give more precise information about the pharmacokinetics of inhalational anesthetics. In this study we investigated the pharmacokinetics of uptake and elimination of sevoflurane in brain, liver, muscle, venous blood and arterial blood of rabbits. METHODS: Twenty rabbits were examined by 19F-MRS conducted at 4.7 Tesla using a 1-cm-diameter surface coil for brain (n = 4), liver (n = 5) and muscle (n = 5), and a 1.3-cm-diameter surface coil for arterial (n = 3) and venous (n = 3) blood. Sevoflurane, 4% in oxygen, was administered for 120 min, followed by 120 min elimination. RESULTS: Both the uptake and elimination kinetics were best fitted by a biexponential curve which was divided into fast and slow components. During the uptake experiment the time required to reach half of the maximum spectroscopic intensity in each tissue was 1.6 min in arterial blood, 4.7 min in liver, 12.2 min in venous blood, 14.4 min in brain and 20.9 min in muscle. During the elimination experiment the time required to reach half maximum intensity was 2.4 min in arterial blood, 6.3 min in liver, 13.4 min in venous blood, 19.6 min in brain and 28.7 min in muscle. CONCLUSIONS: Sevoflurane uptake or elimination in the tissues examined followed biexponential kinetics. In this rabbit model, sevoflurane uptake and elimination were fastest in arterial blood, followed, in order, by liver, venous blood, brain and muscle.

Anesthetics, Inhalation↗
PubMed2000

Induction of acute-phase reactive substances during open-heart surgery and efficacy of ulinastatin. Inhibiting cytokines and postoperative organ injury.

OBJECTIVE: A systemic inflammatory response after open-heart surgery using cardiopulmonary bypass may be responsible for postoperative organ dysfunction. Ulinastatin, a protease inhibitor, plays an important role in host defense under periods of stress. METHODS: We studied the efficacy of ulinastatin on changes in acute-phase reactive substances during and after open-heart surgery. Patients undergoing open-heart surgery were divided into an ulinastatin group (Group U) and a control group (Group C). In Group U, we introduced 600,000 units of ulinastatin into a priming solution for cardiopulmonary bypass, 300,000 units into a cardiopulmonary bypass circuit at the removal of aortic cross-clamping, and 300,000 units a day for 5 days following surgery. RESULTS: Immediately after cardiopulmonary bypass, alpha 1-antitrypsin levels decreased significantly in both groups, and increased significantly on the second day after surgery. Ulinastatin levels decreased after cardiopulmonary bypass in Group C. Significantly high levels of ulinastatin were obtained in Group U. Interleukin-6, interleukin-8, and polymorphonuclear elastase were markedly induced, and high levels of plasma concentration continued for several days after surgery. At all sample points, these concentrations in Group U tended to be lower than those in Group C. A significantly positive correlation was seen between the maximum levels of interleukin-8 and polymorphonuclear elastase, but these cytokine and polymorphonuclear elastase levels did not correlate with parameters such as the duration of anesthesia, surgery, cardiopulmonary bypass, or aortic cross-clamping. CONCLUSIONS: Our study suggests that high-dose ulinastatin administration to maintain a sufficient concentration of circulating protease inhibitors may suppress overinduction of cytokines and polymorphonuclear elastase in open-heart surgery.

Aged↗
PubMed2000

Obesity and postoperative oxygenation after coronary artery bypass grafting.

OBJECTIVE: The relationship between obesity and postoperative oxygenation after coronary artery bypass grafting was studied. METHODS: Subjects were 68 patients undergoing solitary coronary artery bypass grafting--49 men and 19 women with a mean age of 64 years--divided into 3 groups by body mass index: group L with a body mass index of < 20 kg/m2 (n = 10), group M with a 20 < or = body mass index < 25 (n = 46), and group H with a 25 < or = body mass index (n = 12). Perioperative oxygenation was evaluated using respiratory indices measured preoperatively and 3 and 15 hours postoperatively. RESULTS: Postoperative respiratory indices significantly increased from 0.23 to 0.67 (p < 0.001) at 3 hours and to 0.97 (p < 0.01) at 15 hours postoperatively in group L, from 0.27 to 0.80 (p < 0.001) and to 0.94 in group M, and from 0.31 to 1.39 (p < 0.001) and to 1.45 in group H. The postoperative respiratory index in group H was significantly higher (p < 0.01) than that in groups M and L both at 3 and 15 hours postoperatively. Multivariate analysis showed that the coefficients of determination of body mass index to postoperative respiratory index, 23% at 3 hours and 16% at 15 hours postoperatively, were the highest among perioperative factors. CONCLUSIONS: Obesity is a major factor impairing postoperative oxygenation. Careful management in a semirecumbent position and/or nasal intermittent positive pressure ventilation may thus be required in obese patients.

Body Mass Index↗
PubMed2000

Meconium peritonitis in utero.

To clarify the relationship between clinical features in utero and postnatal prognosis, 20 fetuses who underwent ultrasonic (US) evaluation for meconium peritonitis (MP) over a 17-year period were reviewed. According to final US findings in utero, patients were classified into three types. Type I (massive meconium ascites) was noted is 5 cases, type II (giant pseudocyst) in 4, and the other 11 were classified as type III (calcification and/or small pseudocyst). Abdominal calcifications were identified in only 5 cases (2 type I, 1 type II, 2 type III). Seven fetuses who had associated polyhydramnios (1 Type I, 1 Type II, 2 Type III) and fetal hydrops (3 Type II) were delivered before 36 weeks' gestation. Cardiopulmonary resuscitation at birth was required in 9 cases (5 type I, 4 type II) who underwent abdominal drainage before delivery and/or immediately after birth. Although dilatation of the intestine was identified in 10 fetuses (2 type II, 8 Type III), 18 had intestinal atresia and 2 had fecal obstruction of the distal ileum. Four infants (2 type I, 1 type II, 1 type III) died of respiratory failure and postoperative complications. These results indicated that careful fetal US may be useful for perinatal management of MP.

Ascites↗
PubMed2000

Continuous intra-arterial blood gas monitoring during thoracic surgery.

PURPOSE: This study was undertaken to assess the clinical usefulness of a continuous intra-arterial blood gas (CIABG) monitoring system, Paratrend 7, during thoracic surgery. METHODS: A sensor of the CIABG monitoring system was inserted into the radial artery in 50 patients. During one-lung/differential lung ventilation, arterial blood samples for estimation of blood gases (ABG) were taken every 45-90 min or when clinically needed. The PCO(2), PO(2), and pH values displayed by the CIABG monitor were recorded prior to arterial blood sampling and were compared with the results of ABG analysis. The mean (bias) and the standard deviation (precision) of the differences were calculated from the data for each parameter. RESULTS: Ninety-four blood samples were obtained. The correlation between CIABG and ABG measurements was strong for each parameter: r = 0.83 (PCO(2)), 0.89 (PO(2)), 0.74 (pH). The bias +/- precision between the two methods was 0.4 +/- 3.0 mmHg for PCO(2), -6 +/- 47 mmHg for PO(2), -1.2 +/- 27.4% for PO(2) and -0.01 +/- 0.04 for pH. For PO(2) values <150 mmHg, the bias +/- precision was 1 +/- 28 mmHg. CONCLUSION: The agreement between CIABG and ABG measurements was better for PCO(2) and pH than for PO(2). The PO(2) value displayed on the CIABG monitor may not always be reliable during thoracic surgical procedures.

Journal Article↗
PubMed2000

Thoracoscopic treatment of primary chylopericardium.

The development of video-assisted thoracoscopy has changed the practice of thoracic surgery. This report describes a 20-year-old man who successfully underwent thoracoscopic thoracic duct ligation and partial pericardiectomy for primary chylopericardium. We recommend a right-sided thoracoscopic approach to the thoracic duct in the lower thoracic cavity.

Adult↗
PubMed2000

Inducible expression of basic transcription element-binding protein 2 in proliferating smooth muscle cells at the vascular anastomotic stricture.

OBJECTIVE: The proliferation of vascular smooth muscle cells surrounding a suture line is an important factor in the development of anastomotic stricture that is frequently seen after coronary artery bypass grafting. The aim of this study was to investigate the time course of intimal thickening and to examine the expression of the molecular marker of smooth muscle cell activation surrounding the suture line. METHODS: Longitudinal aortotomy was performed in the abdominal aorta of rats. The rats were put to death 1, 2, 4, and 8 weeks after aortotomy, and the percentage of the lumen occluded by intimal thickening was calculated. All tissues were stained with antibodies against basic transcription element- binding protein 2, human cyclin-dependent kinase (cdk4), and Sp1 for immunohistochemistry. Basic transcription element-binding protein 2 is a transcription factor that is involved in phenotypic modulation of vascular smooth muscle cells. Cdk4 represents a marker for G(1) phase of the cell cycle. Sp1 is a transcription factor known to be expressed in a variety of tissues. Basic transcription element-binding protein 2 messenger RNA expression was confirmed by means of reverse transcriptase-polymerase chain reaction. RESULTS: We noted significant thickening of the intimal layer 1 week after aortotomy. Immunohistochemistry demonstrated that smooth muscle cells in the neointima were strongly positive for basic transcription element-binding protein 2 and human cyclin-dependent kinase 4, which peaked 2 weeks after aortotomy. Basic transcription element-binding protein 2 expression was closely associated with human cyclin-dependent kinase 4 expression in the neointima, although Sp1 was not. Basic transcription element-binding protein 2 messenger RNA levels were significantly up-regulated early after aortotomy. CONCLUSION: The experimental rat aortotomy model is useful to investigate the proliferation of vascular smooth muscle cells around the suture line. Moreover, our results suggest the possible role of basic transcription element-binding protein 2 in the development of vascular anastomotic strictures.

Anastomosis, Surgical↗
PubMed2000

Intracorporeal imaging and differentiation of living tissue with an ultra-high-frequency ultrasound probe.

Intraoperative diagnostic tissue differentiation is expected to be useful clinically. We have fabricated a 3-mm diameter rod-shaped ultrasound (US) probe mounted with a 120-MHz transducer whose lateral resolution is the same as the cellular size of 13 microm. The probe can image a microscopic structure (i.e., the cellular arrangement inside intracorporeal living tissue). We imaged normal kidney tissue of a living mouse and tumor tissue implanted in another mouse kidney. We anesthetized the mice, exteriorized the kidneys, and punctured the kidneys with the probe. Renal corpuscle-like structures were seen in the healthy kidney, but a wavy spindle-like structure was seen in the tumor. The similarity between the ultrasonic images and histological sections taken from the imaged organs demonstrates the possibility of real-time tissue differentiation by ultra-high-frequency US.

Animals↗
PubMed2000

Ultrasonographic evaluation of the influence of different postures on diaphragmatic motion in mechanically ventilated patients.

We confirmed a diaphragmatic motion during mechanical ventilation in four patients with central nervous system damage. The right hemidiaphragm were visualized with 3.5 MHz ultrasound, and motion was measured using time-motion analysis in separate postures. The dome was most impaired during the right decubitus posture. The crural region was most improving during the left decubitus posture. The costal region was most impaired during the sitting posture. The motion of the dependent region was impaired.

Adolescent↗
PubMed2000

Rhabdoid tumour of the lung is a dedifferentiated phenotype of pulmonary adenocarcinoma.

AIMS: Primary rhabdoid tumour of the lung is rare, and histological and biological characteristics have not been fully documented. We describe three cases of primary lung rhabdoid tumour, all associated with adenocarcinoma, and investigate the histological features and biological characteristics. METHODS AND RESULTS: Three cases were obtained from a total 902 cases of surgically removed primary lung tumours between 1986 and 1998. The rhabdoid cells were found to occupy about 50-90% of each tumour. All of the tumours had nonrhabdoid adenocarcinoma foci in the centre of the tumours. Transition between the adenocarcinomatous and rhabdoid components was demonstrated. Detailed immunohistochemical studies were carried out. The epithelial markers, cytokeratins and epithelial membrane antigen (EMA), were strongly expressed in rhabdoid and adenocarcinomatous components. Furthermore, surfactant apoprotein A was positive in both components in one case, but myoglobin, MyoD and HHF35 were not expressed. Vimentin was strongly and diffusely stained in all cases. The neuroendocrine markers, chromogranin A (all cases), neuron-specific antigen (NSE) (two cases) and CD56 (one case) were occasionally positive in only a small number of the rhabdoid tumour cells. GM-CSF was positively stained in one case, and the dedifferentiated characteristics of the rhabdoid cells was suggested. Proliferative cell nuclear antigen (PCNA) was strongly demonstrated in the rhabdoid tumour cells (all cases). To gain better understanding the highly proliferative characteristics of the tumours, p53 gene (exons 5-8) mutation was examined by DNA sequencing analysis; mutation of the p53 DNA was not detected. Overexpression of p53 protein was also not demonstrated in all cases. HPV6 was demonstrated in one case by PCR method and also non-isotopic in-situ hybridization (NISH). Two cases died in a short period of time (3 years and 4 months, respectively). CONCLUSION: The rhabdoid cells in these three cases were considered to represent the dedifferentiated components of the accompanying adenocarcinoma. Dedifferentiated characteristics (neuroendocrine markers, GM-CSF, vimentin, and the aggressive behaviour) were evident.

Adenocarcinoma↗