Biomedical subjects

M Onizuka

Publications and source records attributed to M Onizuka.

At least 19 recordsLinked to original sources

PubMed2006

New method for evaluation of lung lymph flow rate with intact lymphatics in anaesthetized sheep.

AIM: Lung lymph has commonly been studied using a lymph fistula created by tube cannulation into the efferent duct of the caudal mediastinal node in sheep. In this method, the tail region of the caudal mediastinal node is resected and the diaphragm is cauterized to exclude systemic lymph contamination, and cannulation is performed into one of the multiple efferent ducts originating from the caudal mediastinal node. Moreover, the pumping activity of lymphatics might be diminished by cannulation. Therefore, the purpose of the study was to evaluate the flow rate of lung lymph with maintenance of intact lymphatic networks around the caudal mediastinal node to the thoracic duct in sheep. METHODS: An ultrasound transit-time flow meter was used to measure lung lymph flow. The thoracic duct was clamped just above the diaphragm and the flow probe was attached to the thoracic duct just after the last junction with an efferent duct from the caudal mediastinal node. The lung lymph flow rate was measured at baseline and under conditions of lung-oedema formation. RESULTS: The baseline lung lymph flow rate in our model was three- to sixfold greater than values obtained with the cannulation method. With oedema-formation, the lung lymph flow rate was the same as that measured using cannulation. CONCLUSION: The lung lymph flow was unexpectedly large under the conditions of the study, and our data suggest that the drainage effect of lymphatics is significant as a safety factor against pulmonary oedema formation.

Animals↗

PubMed2006

Elastase-induced aneurysms in rabbits: effect of postconstruction geometry on final size.

BACKGROUND AND PURPOSE: Elastase-induced aneurysms in rabbits have become an accepted model to study endovascular treatment. The size and shape of the resulting aneurysms may vary widely. Our goal was to predict the final aneurysm morphology on the basis of immediate postinduction geometry. METHODS: Thirty New Zealand white rabbits were used. Aneurysms were created at the origin of the right common carotid artery (CCA). Intraluminal incubation of elastase was applied to the origin of CCA with proximal balloon occlusion of the artery. The aneurysms were allowed to mature for 3 weeks and evaluated by digital subtraction angiography. We retrospectively measured neck diameter, dome height, and aneurysm diameter, as well as the angle between the parent artery and the main axis of the aneurysm neck. We performed correlation analysis with immediate postinduction geometry. RESULTS: The diameter of the origin of the CCA measured immediately after elastase incubation correlated positively to the mature aneurysm neck (P < .01). Moreover, the aneurysm neck both after the aneurysm creation and at 3-week follow-up had a positive correlation with the final dome height (P < .05). Finally, the dome height was related to the angle between the centerline of the innominate artery and axis of the aneurysm neck for dome diameter-to-neck ratio of <1.5 (P < .05). CONCLUSION: These results indicate that neck width immediately after creation and the curvature of the parent artery are linked to the final aneurysm dimensions, and we may be able to predict the size of aneurysm on the day of creation.

Angiography↗

PubMed2006

Direct carotid puncture for the endovascular treatment of anterior circulation aneurysms.

We report the usefulness of Guglielmi detachable coil (GDC) embolization by direct carotid puncture for anterior circulation aneurysms. For all 27 patients, GDC embolization by direct carotid puncture was safely performed by using a 5F sheath introducer 5 cm long and a Tracker-38 catheter. Neurologic deficits and hemorrhage were not found in any patient during the follow-up period. If the transfemoral approach cannot be applied, GDC embolization should be considered as an alternative method.

Aged↗

PubMed2006

The significance of incomplete stent apposition in patients undergoing stenting of internal carotid artery stenosis.

BACKGROUND AND PURPOSE: Incomplete stent apposition after carotid angioplasty and stent placement (CAS) is often seen but little is known about how the incomplete attachment goes after stent placement. For example, some may change into restenosis around the stent edge and some may remain unchanged. The purpose of this study is to clarify the morphologic prognosis of an incomplete stent apposition at the stent edge. METHODS: CAS was attempted on 135 consecutive stenotic lesions (124 patients). Angiograms were then evaluated immediately after the procedure. An incomplete stent apposition at stent edge was found in 15 patients, and all of them were followed up by angiography and MR imaging with antiplatelet therapy. RESULTS: No ischemic event caused by the lesions occurred during the mean follow-up period of 11 months (from 4 to 32 months). The angiography findings of 15 lesions at a mean of 8.8 months (from 2 to 28 months) after CAS showed that all remained unchanged. No patients required any additional intervention. No new ischemic lesions were detected in any of the 15 patients who underwent follow-up MR imaging at a mean of 10 months (from 2 to 32 months) after CAS. CONCLUSION: In this study, the existence of a segment of incomplete stent apposition had no adverse morphologic or clinical effect.

Aged↗

PubMed2005

Increased frequency of the angiotensin-converting enzyme gene D-allele is associated with noninfectious pulmonary dysfunction following allogeneic stem cell transplant.

Noninfectious pulmonary dysfunction (NIPD) is a common and often fatal complication associated with allogeneic hematopoietic stem cell transplantation (HSCT). An insertion/deletion polymorphism in the angiotensin-converting enzyme (ACE) gene has been extensively studied in relation to cardiovascular and renal disease, and lung fibrosis. In pulmonary fibrosis, D-allele frequency is significantly higher than in the control population. We hypothesized that a similar mechanism exists between post-HSCT NIPD and pulmonary fibrosis in the absence of HSCT. We retrospectively analyzed the incidence of NIPD and the ACE genotype polymorphism in 118 Japanese patients who underwent HSCT from HLA-identical sibling donors. NIPD occurred in 17 cases. Deletion/deletion genotype carriers were more common in the NIPD group than in the other 101 patients (41.2 vs 11.9%; hazard ratio, 5.19; 95% confidence interval, 1.67-16.21). There were no significant relationships between the clinical characteristics of patients and the development of NIPD. These findings suggest that the ACE genotype is associated with the development of NIPD following HSCT. This study is the first to report the relationship between genetic background and NIPD.

Adolescent↗

PubMed2002

[Resection for pulmonary metastasis of gastrointestinal stromal tumor of the stomach at 10 years after gastrectomy; report of a case].

A 70-years-old male, who had received gastrectomy for leiomyosarcoma of the stomach 10 years ago, was found to have a left lung tumor on chest X-ray and computed tomography (CT). The tumor was diagnosed to be a pulmonary metastasis of gastric leiomyosarcoma. On admission, another tumor was detected at left occipital region by brain CT and was thought to be meningioma. Left lower lobectomy and brain tumor resection were performed serially. The histologic and immunohistochemical findings showed that both tumors were metastases of gastrointestinal stromal tumor (GIST) of the stomach after long disease-free interval. Compared with the primary tumor, cellular density, mitotic figures, bizarre nuclei, and necrotic foci were prominent in the metastatic tumors. This case suggest that GIST may recurrent as pulmonary metastasis after long disease-free interval and should be follow up longer after resection. Patient prognosis with pulmonary metastases is considered to be reflected more exactly in biological malignant potential of metastatic tumor rather than that of primary tumor.

Aged↗

PubMed2002

Effect of phosphodiesterase III inhibitor (Olprinone) on thoracic duct lymph flow in anesthetized sheep with experimentally induced heart failure by endothelin-1.

We investigated the short-term effects of a phosphodiesterase III inhibitor (Olprinone) on hemodynamics and thoracic duct lymph flow in anesthetized open-chest sheep with heart failure induced by endothelin-1 (cardiogenic shock). Ultrasound transit-time flow probes were attached to the thoracic duct, the ascending aorta and the renal artery. Arterial, pulmonary and central venous pressures were monitored. Endothelin-1 was infused intravenously at a dosage that reduced cardiac output to 50% or more of baseline (n=11). The effects of Olprinone were examined (n=5) by intravenous infusion after endothelin-1 administration. Other sheep (n=6) were used as controls. Olprinone significantly increased cardiac output that had been decreased by endothelin-1 and further increased thoracic duct flow that had been increased by endothelin-1. Increased arterial and pulmonary pressures induced by endothelin-1 administration were rapidly decreased by Olprinone. Renal arterial flow and central venous pressure were, however, unchanged by Olprinone. Overall, Olprinone acutely improved experimental cardiogenic shock (heart failure) induced by endothelin-1, and maintained thoracic duct lymph flow at a high level after endothelin-1 administration.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed2001

Innominate artery rupture after transcervical drainage for descending necrotizing mediastinitis.

We present a case of innominate artery rupture after descending necrotizing mediastinitis (DNM) on day 36 of cervicomediastinal drainage. The patient recovered after aortosubclavian arterial bypass grafting followed by resection of the eroded artery. Because mechanical pressure caused by drains in addition to the inflammatory process can cause major vessel erosion, prolonged transcervical tube drainage for treating descending necrotizing mediastinitis should be avoided even if the drains applied are soft and thin.

Aortic Dissection↗

PubMed2001

Topographical analysis of p53 expression and DNA ploidy in early bronchial squamous cell carcinoma and preneoplastic lesions.

The significance of p53 mutations and DNA aneuploidy in carcinoma cells has been investigated on the basis of a multi-step development theory of carcinogenesis. It has, however, not been determined whether these alterations can be used as diagnostic markers for the early detection of bronchial squamous cell carcinoma (BSqCC). To address this problem, we topographically investigated p53 alterations and DNA aneuploidy in 24 X-ray-negative, early BSqCC patients with various preneoplastic lesions and in 25 non-carcinoma patients with preneoplastic lesions. Bronchial lesions (n=88) were morphologically classified as hyperplasia (HP, n=5), squamous metaplasia (SM, n=23), low-grade dysplasia (LGD, n=14), high-grade dysplasia (HGD, n=11), intraepithelial carcinoma including 'carcinoma in situ' (CIS) (IEC, n=15), and microinvasive carcinoma (MIC, n=20). Immunohistochemistry for the p53 protein and image cytometry for DNA ploidy detection were performed in serial sections of each lesion. Overexpression of p53 protein was detected in 36, 73, and 65% of the HGD, IEC, and MIC lesions, respectively. Aneuploid DNA profiles were found only in carcinoma lesions, 33% in IEC and 85% in MIC. The topographical analysis revealed two types of early BSqCCs, one with adjacent preneoplastic lesions (sequential type, n=8) and another without such lesions (de novo type, n=16). The p53 protein was frequently overexpressed in both types (sequential type, 79%; de novo type, 62%). In the sequential type, however, the p53 protein was overexpressed in HGD lesions that were directly adjacent to p53-overexpressing carcinoma lesions without exception. The present topographical study suggests that p53 mutations play an important role in the carcinogenesis of BSqCC and that p53-overexpressing HGD lesions in sequential types should be regarded as 'truly' preneoplastic lesions that actually develop into carcinomas. In addition, our study demonstrated that DNA aneuploidy might occur at times after p53 alteration with increasing frequency, as invasive growth begins. Such combination analysis of p53 immunohistochemistry and nuclear DNA ploidy in routine histology may contribute to estimates of malignant potential in preneoplastic and intraepithelial squamous lesions and provide additional information for early detection of BSqCC.

Aneuploidy↗

PubMed2001

TSLC1 is a tumor-suppressor gene in human non-small-cell lung cancer.

The existence of tumor-suppressor genes was originally demonstrated by functional complementation through whole-cell and microcell fusion. Transfer of chromosome 11 into a human non-small-cell lung cancer (NSCLC) cell line, A549, suppresses tumorigenicity. Loss of heterozygosity (LOH) on the long arm of chromosome 11 has been reported in NSCLC and other cancers. Several independent studies indicate that multiple tumor-suppressor genes are found in this region, including the gene PPP2R1B at 11q23-24 (ref. 7). Linkage studies of NSCLC are precluded because no hereditary forms are known. We previously identified a region of 700 kb on 11q23.2 that completely suppresses tumorigenicity of A549 human NSCLC cells. Most of this tumor-suppressor activity localizes to a 100-kb segment by functional complementation. Here we report that this region contains a single confirmed gene, TSLC1, whose expression is reduced or absent in A549 and several other NSCLC, hepatocellular carcinoma (HCC) and pancreatic cancer (PaC) cell lines. TSLC1 expression or suppression is correlated with promoter methylation state in these cell lines. Restoration of TSLC1 expression to normal or higher levels suppresses tumor formation by A549 cells in nude mice. Only 2 inactivating mutations of TSLC1 were discovered in 161 tumors and tumor cell lines, both among the 20 primary tumors with LOH for 11q23.2. Promoter methylation was observed in 15 of the other 18 primary NSCLC, HCC and PaC tumors with LOH for 11q23.2. Thus, attenuation of TSLC1 expression occurred in 85% of primary tumors with LOH. Hypermethylation of the TSLC1 promoter would seem to represent the 'second hit' in NSCLC with LOH.

Animals↗

PubMed2001

Asymptomatic brain tumor detected at brain check-up.

Brain check-up was performed in 4000 healthy subjects who underwent medical and radiological examinations for possible brain diseases in our hospital from April 1996 to March 2000. Magnetic resonance imaging revealed 11 brain tumors which consisted of six meningiomas, three pituitary adenomas, one astrocytoma, and one epidermoid cyst. The detection rate of incidental brain tumor in our hospital was 0.3%. Nine patients underwent surgery, with one case of morbidity due to postoperative transient oculomotor nerve paresis. The widespread use of brain check-up may increasingly detect asymptomatic brain tumors. Surgical indications for such lesions remain unclear, and the strategy for treatment should be determined with consideration of the patient's wishes.

Adenoma↗

PubMed2001

Computer-assisted neurosurgical navigational system for transsphenoidal surgery--technical note.

Transsphenoidal surgery carries the risk of carotid artery injury even for very experienced neurosurgeons. The computer-assisted neurosurgical (CANS) navigational system was used to obtain more precise guidance, based on the axial and coronal images during the transsphenoidal approach for nine pituitary adenomas. The CANS navigator consists of a three-dimensional digitizer, a computer, and a graphic unit, which utilizes electromagnetic coupling technology to detect the spatial position of a suction tube attached to a magnetic sensor. Preoperatively, the magnetic resonance images are transferred and stored in the computer and the tip of the suction tube is shown on a real-time basis superimposed on the preoperative images. The CANS navigation system correctly displayed the surgical orientation and provided localization in all nine patients. No intraoperative complications were associated with the use of this system. However, outflow of cerebrospinal fluid during tumor removal may affect the accuracy, so the position of the probe when the tumor is removed must be accurately determined. The CANS navigator enables precise localization of the suction tube during the transsphenoidal approach and allows safer and less-invasive surgery.

Acromegaly↗

PubMed2001

[Placement of stent for internal carotid artery stenosis in the cervical portion improved ocular ischemic syndrome].

We report a case of ocular ischemic syndrome due to severe stenosis of the internal carotid artery. The patient was a 67-year-old man with a hemispheric transient ischemic attack and an amaurosis fugax. Ocular examination showed multiple soft exudates and dilatation of the retinal veins. Carotid stenting was performed to reconstruct the internal carotid artery. The multiple soft exudates were almost diminished and the visual acuity was improved. These results suggest that carotid stenting for severe stenosis of the internal carotid artery should be one of the less invasive methods to improve the microcirculation of the retina.

Aged↗

PubMed2001

[Cerebral arteritis and cerebritis caused by subdural empyema: two cases report].

We report two cases of cerebral angitis and cerebritis caused by subdural empyema. A 22-year-old man, who complained of a headache and high fever, suddenly developed unconsciousness and right hemiparesis. CT and MRI demonstrated left subdural empyema with diffuse brain swelling. CT angiography showed diffuse narrowing of the left internal carotid artery, middle cerebral artery, and anterior cerebral artery. Although we performed craniotomy, continuous irrigation with drainage, systemic injection of antibiotics for subdural empyema, antiplatelet therapy, and hyperbaric oxygen therapy for angitis, his condition remained unchanged. A 67-year-old man who had previously undergone burr hole surgery presented to our hospital for the treatment of scalp infection. He suddenly developed unconsciousness and right hemiparesis. CT and MRI demonstrated left subdural empyema with diffuse brain swelling, but MR angiography did not show any abnormal findings. Hemiparesis improved after the surgery and systemic injection of the antibiotics. Subdural empyema with sinusitis or meningitis around the skull base sometimes causes cerebral angitis. We considered that the angiographical evaluation for the subdural empyema was necessary to detect angitis.

Adult↗

PubMed2001

[Penetrating head injury caused by an icepick].

The patient was a 39-year-old man, with a three year history of schizophrenia, who attempted suicide by piercing his head with an icepick. Spinal cord injuries and shock caused by falling from the fifth floor of the building following this penetrating injury were also noted on admission. The CT scan revealed that the icepick had deeply penetrated the posterior fossa from the forehead. No new neurological deficits or cerebrospinal fluid leakage appeared after admission. The icepick was removed completely without difficulty. In penetrating head injuries, early assessment with cerebral angiography to determine the extent of vascular injury is useful for deciding if surgery should be performed.

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

Thoracic duct lymph flow and its driving pressure in anesthetized sheep.

We examined the relationship between thoracic duct lymph flow (TDF) and its driving pressure (DP) in six anesthetized sheep. DP was determined as the thoracic duct pressure (TDP) minus the innominate vein pressure (VP). TDF was measured using an ultrasound transit-time flow meter, placing a flow probe beside the caudal mediastinal lymph node. TDP was measured with a fine needle inserted near the flow probe. TDP increased linearly together with an increase in VP after balloon inflation in the cranial vena cava with a TDP/VP ratio of 0.79. DP decreased, therefore, with an increase in VP and this decrease in DP correlated directly with a fall in TDF. After rapid i.v. fluid infusion, TDF increased but DP varied among the six sheep. Nonetheless, after balloon inflation with expanded volume (i.e., i.v. fluid infusion), DP and TDF were positively correlated. We conclude that DP is the main factor determining TDF when VP rises in conjunction with increased lymph production.

Animals↗

PubMed1999

Characteristics of symptomatic chronic subdural haematomas on high-field MRI.

We studied the frequency of various features of the appearances on high-field MRI in symptomatic patients with chronic subdural haematomas (CSDH). The ability to predict recurrence after treatment with one burr-hole procedure using MRI was evaluated. A total of 40 patients with symptomatic CSDH underwent MRI at 1.5 T. All haematomas were evacuated within a few days of the MRI examination. Symptomatic CSDH were divided into five groups according to the MRI findings: group A (11 cases), isointense or low signal on T1- and low signal on T2-weighted images; group B (18 cases), high signal on T1- and low signal on T2-weighted images; group C (5 cases), high signal on both T1- and T2-weighting; group D (1 case), low signal on T1- and high signal on T2-weighted images; group E (5 cases), heterogeneous intensity on T1- and T2-weighting throughout the haematoma cavity. The mean interval between onset of symptoms and MRI for group A was 5.0 +/- 4.1 days, which was significantly shorter than that for group B (9.4 +/- 4.4 days, P < 0.02), group C (27.8 +/- 20 days, P < 0.005) or group E (17.8 +/- 12.2 days, P < 0.01). Recurrence was seen in three haematomas of group A and one of group B. Reoperation was most closely correlated with diffuse low signal on T2-weighted images but not with a multiloculated appearance. Low signal on T2 weighting was surprisingly high (72.5%) and the age of the haematomas as estimated on the MRI correlated well with the interval between the onset of symptoms and MRI. Our findings support the causative role of recurrent bleeding in the enlargement of CSDH.

Adult↗