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Biomedical subjects

T Yoshimoto

Publications and source records attributed to T Yoshimoto.

At least 181 records · Page 10Linked to original sources
PubMed1999

Intra-operative premature rupture of the cerebral aneurysms. Analysis of the causes and management.

The causes and management of intra-operative premature rupture are analysed and discussed. During the past 6 years, the authors, performed 398 consecutive direct surgical interventions for ruptured cerebral aneurysms. Intra-operative premature rupture is defined as a rupture which occurs before the securing of the parent arteries or the neck of the aneurysm and is out of control, at least temporarily. The causes and management were retrospectively analyzed by reviewing video tape recordings. Intra-operative premature ruptures which met the above definition occurred in 24 cases (6.0%). The causes were as follows: 1.) dural opening and arachnoid opening (8.3%), 2.) haematoma removal (12.5%), 3.) brain retraction (16.7%), 4.) aneurysm dissection (62.5%). A double suction technique was used to control bleeding and haemostasis with a small piece of cotton or a temporary clip, performed in 20 cases (83.3%). However, in cases with premature rupture immediately after the dural or arachnoid opening, the extension of the haematoma into the subarachnoid space resulted in severe brain swelling and partial resection of the brain had to be done to secure temporary clipping. The double suction technique and primary haemostasis using a small piece of cotton or temporary clip resulted in good outcome even in cases with premature rupture. However, very early premature rupture also occurred although its incidence was extremely rare. The removal of part of the brain can secure the working space but the outcome was poor.

Adult↗
PubMed1999

Circulating blood volume in patients with subarachnoid haemorrhage.

To establish the fluid management for patients with subarachnoid haemorrhage (SAH), circulating blood volume (BV) was measured by pulse-spectrophotometry using indocyanine green (ICG) in 34 cases with SAH and 20 cases with neurosurgical disorders as control. BV measured immediately after induction of anaesthesia was lower in cases with SAH than that in controls. (62.8+/-12.3 vs. 73.3+/-11.2 ml/kg, p<0.01). In cases with SAH, the BV was significantly decreased in females (p<0.05) but not so significantly in males. In female cases with SAH, reduced BV was increased 3 days after operation (p<0.01). In conclusion BV is decreased in cases with SAH, especially in females. Active fluid therapy may be necessary when temporary vascular occlusion is required during aneurysm surgery. Since hypovolaemia may cause symptomatic vasospasm, BV measurement with pulse-spectrophotometry may provide useful information to insure normovolaemia.

Adult↗
PubMed1999

Vasculo-protective effects of insulin sensitizing agent pioglitazone in neointimal thickening and hypertensive vascular hypertrophy.

A novel insulin sensitizing agent, thiazolidine, has been demonstrated to inhibit the growth of cultured vascular smooth muscle cells (VSMC) in vitro. This study was undertaken to examine the in vivo effects of the thiazolidine compound pioglitazone (PIO) on carotid neointimal thickening, after endothelial injury in Wistar rats and vascular hypertrophy in stroke-prone spontaneously hypertensive rats (SHR-SP/Izm). PIO treatment (3 mg/kg/day for 1 week prior to endothelial injury and 2 weeks postendothelial injury) remarkably decreased neointimal cross-sectional areas in treated animals (63.8 +/- 4.9 x 10(3) microm2) versus controls (196 +/- 7.6 x 10(3) microm2, P < 0.05). Bromodeoxyuridine uptake in the neointima, a marker of DNA synthesis, was also decreased after treatment compared with controls. In SHR-SP/Izm but not in Wistar rats, PIO treatment decreased blood pressure and plasma insulin levels. PIO treatment in SHR-SP/Izm (3 mg/kg/day from 4 weeks of age for 7 weeks) significantly decreased the medial wall thickness of the mesenteric artery (10.4 +/- 1.2 x 10(3) microm2 versus control, 21.2 +/- 2.4 x 10(3) microm2, P < 0.05). In addition, PIO treatment significantly decreased the expression of EIIIA fibronectin both in the carotid neointima of Wistar rats and the media of the mesenteric artery in SHR-SP/Izm compared with their respective controls (P < 0.05). These results suggest that PIO has vasculo-protective effects in both acute and chronic vascular injury in vivo through inhibition of VSMC proliferation.

Animals↗
PubMed1999

Induction of heme oxygenase produces load-independent cardioprotective effects in hypertensive rats.

Although heme oxygenase (HO) has been suggested to be involved in the regulation of cardiovascular function through production of carbon monoxide (CO), the pathophysiological significance of HO in hypertensive organ damage remains unknown. We examined the effects of inducing HO-1 mRNA by stannous chloride (SnCl2) on cardiac hypertrophy in stroke-prone spontaneously hypertensive rats (SHR-SP/Izm). Chronic administration of SnCl2 resulted in a significant decrease in left ventricular (LV) weight/body weight ratio and LV brain natriuretic peptide (BNP) mRNA levels as a marker of cardiac hypertrophy and a significant increase in LV HO-1 mRNA levels and LV cGMP contents in SHR-SP/Izm, while there was no significant change in systemic blood pressure. These results provide the first evidence that induction of HO in the heart attenuates cardiac hypertrophy in load-independent mechanism in genetically hypertensive rats.

Animals↗
PubMed1999

Evaluation of neuronal loss in adult moyamoya disease by 123I-iomazenil SPECT.

BACKGROUND: Central benzodiazepine (BZD) receptor imaging is effective to evaluate neuron density in the pathological brain cortex. This study used BZD receptor imaging to evaluate neuronal damage in adult ischemic moyamoya disease. METHODS: Single photon emission computed tomography and a novel tracer, 123I-iomazenil, were used to measure BZD receptor density in the brain. Evaluation of early and late images was performed in three asymptomatic, unoperated patients, and six mildly symptomatic, operated patients. RESULTS: Uptakes in the frontal, parietal, and occipital lobes of symptomatic patients were significantly lower (p<0.05) than those of asymptomatic patients. The late image/ early image count ratios (L/E ratios) of asymptomatic patients were relatively constant (mean, 0.571; range, 0.550-0.581) in all regions of interest. In contrast, the L/E ratios of symptomatic patients were not uniform. CONCLUSIONS: The neuron density was preserved in adult asymptomatic patients despite harboring moyamoya disease. In contrast, the neuronal density was decreased in symptomatic patients even though their symptoms were mild and they had undergone revascularization.

Adolescent↗
PubMed1999

Non-anastomotic bypass surgery for childhood moyamoya disease using dural pedicle insertion over the brain surface combined with encephalogaleomyosynangiosis.

BACKGROUND: Anastomotic bypass surgery for childhood moyamoya disease provides more rapid improvement of blood circulation than indirect non-anastomotic bypass surgery, but there are several problems, such as the technical difficulty of the operation, the extended period of anesthesia, and temporary occlusion of blood flow in the vessels of the brain surface. METHODS: We describe a new non-anastomotic bypass procedure using dural pedicle insertion over the brain surface combined with encephalogaleomyosynangiosis and preservation of the superficial temporal artery (STA). We treated nine patients with childhood moyamoya disease admitted to our institution from 1989 through 1994. The operative field was determined based on the ischemic site identified by preoperative neuroimaging methods. Our procedure was performed in a total of 15 hemispheres, and the patients have been followed up for 5 months to 5 years after operation. RESULTS: Cerebral angiography, cerebral blood flow measurements, and clinical symptoms and signs were improved at the operation site in all patients. Because the STA and the superficial portion of the temporal muscle attached to the skin flap were preserved, the skin at the operation site was not depressed and no necrosis, infection, or alopecia developed. CONCLUSION: Childhood moyamoya disease is progressive, so repeated bypass surgery may be required. Therefore, non-anastomotic bypass surgery is better for the first operation because the STA is preserved. The present procedure using temporal muscle, galea, and dura can be extended over a wider brain surface than the operative field, and is suitable for establishing collateral circulation in the frontal lobe. Blood flow in the skin flap is maintained, so the cosmetic result is satisfactory.

Cerebral Angiography↗
PubMed1999

Arachnoid membrane closure. Prevention of postoperative cerebrospinal fluid leakage.

BACKGROUND: Opening the arachnoid membrane causes leakage of the cerebrospinal fluid (CSF). CSF spillage and collection in the subdural, epidural, and/or subcutaneous space are occasionally seen on a postoperative CT scan. Closure of the arachnoid membrane is considered to be unnecessary because most of the fluid in the extracerebral space is temporary and disappears spontaneously. However, in some cases, this CSF collection results in serious complications such as brain compression, extracerebral hematoma, intractable meningitis, and skin problems. In this study for prevention of CSF leakage, the arachnoid membrane was tightly closed with 10-0 nylon after a small opening was made for cerebrovascular bypass surgery. METHODS: The arachnoid membrane closure was performed in 18 patients (20 sides) after bypass surgery between 1994 and 1995. As a control, 51 patients (57 sides) had conventional bypass surgery without the arachnoid membrane closure. RESULTS: The radiological findings revealed that only one (5%) of the patients had a small fluid collection after arachnoid membrane closure, which was significantly lower than the control (49%). CONCLUSION: Arachnoid membrane closure is a simple technique and is effective for prevention of postoperative extracerebral CSF collection.

Arachnoid↗
PubMed1999

Coexistence of intracranial arteriovenous malformation with Turcot's syndrome: a case report.

Turcot's syndrome is a combination of multiple adenomatous gastrointestinal polyps and neuroepithelial tumors of the central nervous system (CNS). A 16-year-old man presented with Turcot's syndrome consisting of nonfamilial colorectal polyposis and multiple fibrillary astrocytomas accompanied by ruptured intracranial arteriovenous malformation (AVM) manifesting as generalized epileptic activity. Multiple CNS tumors are extremely unusual in Turcot's syndrome. This is the first description of Turcot's syndrome associated with an intracranial AVM. This case may correspond to a new phenotypic variant of colonic polyposis syndrome.

Adenomatous Polyposis Coli↗
PubMed1999

Antegrade recanalization of completely embolized internal carotid artery after treatment of a giant intracavernous aneurysm: a case report.

BACKGROUND: Parent artery occlusion is one of the traditional methods of treatment for unclippable aneurysms. However, parent artery occlusion may not result in permanent exclusion of the aneurysm from the systemic circulation. We present a case of cerebral aneurysm treated by proximal embolization of the parent artery, which recanalized during the follow-up period. CASE DESCRIPTION: A 69-year-old woman presented with a right blepharoptosis and diplopia. A large aneurysm arising from the cavernous portion of the right internal carotid artery was found and endovascularly excluded from the cerebral circulation by proximal internal carotid artery occlusion with balloons. Eleven days after treatment, occlusion of the parent artery and obliteration of the aneurysm were angiographically confirmed. However, the parent artery was found to be recanalized with nearly total obliteration of the aneurysm at the follow-up 6 months after treatment. CONCLUSION: Angiography suggested that recanalization took place through the vaso vasorum. We believe that recanalization was induced by marginal cerebral blood flow in the ipsilateral hemisphere.

Aged↗
PubMed1999

Liquid jets, accelerated thrombolysis: a study for revascularization of cerebral embolism.

A prior study has reported that a rapid recanalization therapy of cerebral embolism, using liquid jet impacts generated by the interaction of gas bubbles with shock waves, can potentially penetrate through thrombi in as little as a few microseconds with very efficient ablation (Kodama et al. 1997). The present study was undertaken to examine the liquid jet impact effect on fibrinolysis in a tube model of an internal carotid artery. First, the conditions for generating the maximum penetration depth of liquid jets in the tube were investigated. Gelatin was used to mimic thrombi. The shock wave was generated by detonating a silver azide pellet weighing about a few micrograms located in a balloon catheter. The collapse of the inserted gas bubbles and the subsequent liquid jet formation were recorded with high-speed photography. Second, thrombi were formed using fresh human blood from healthy volunteers. The fibrinolysis induced by the liquid jet impact with urokinase was explored. This was conducted under selected conditions based on the experiment using the gelatin. Fibrinolysis was calculated as the percentage of the weight loss of the thrombus. Fibrinolysis with urokinase alone and with a single liquid jet impact with urokinase was 1.9 +/- 3.7% (n = 16) and 20.0 +/- 9.0% (n = 35), respectively, for an incubation time of 60 min. Statistical differences were obtained between all groups (ANOVA). These results suggest that liquid jet impact thrombolysis has the potential to be a rapid and effective therapeutic modality in recanalization therapy for patients with cerebral embolism and other clinical conditions of intra-arterial thrombosis.

Carotid Artery, Internal↗
PubMed1999

Imaging the pyramidal tract in patients with brain tumors.

The clinical usefulness of diffusion-weighted magnetic resonance imaging (DWI) of the pyramidal tract was evaluated in patients with brain tumors. Five normal volunteers and seven patients with glioma (n = 4) or meningioma (n = 3) near the pyramidal tract underwent coronal echo planar DWI. Greyscale DWIs in each of the three orthogonal diffusion gradients were transformed into graduations, color-coded as red, green or blue, respectively, and then composited to form a combined color image. The entire pyramidal tract was visualized on a single fiber mapping image by combining the upper half of the image slice including the primary motor cortex, the corona radiata and the internal capsule with the lower half of the image slice including the internal capsule, the cerebral peduncle and the ventral brain stem. Fiber mapping images demonstrated the pyramidal tract as a distinct band indicating nerve fiber integrity in all volunteers. The entire pyramidal tract from the primary motor subcortex to the ventral brain stem could be traced. Fiber mapping images showed the ipsilateral pyramidal tract as either discontinuous due to impaired anisotropy or compressed due to mass effect in patients with brain tumors. These findings corresponded well with the pre- and postoperative motor functions. Fiber mapping images are useful for evaluating the white matter neuronal tracts and can provide indications for determining surgical strategy.

Adult↗
PubMed1999

Large-scale preparation of high-molecular weight DNA from buccal mucosa.

Four non-invasive methods of sampling DNA from buccal mucosa, simple rinses, scrubbing with cotton balls, scrubbing with toothbrushes and rinses after scrubbing with toothbrushes, were investigated. Scrubbing with toothbrushes yielded 5.79 +/- 5.56 microg of DNA rich in high-molecules, while less than one eighth the amount was recovered by scrubbing with cotton balls. Rinses after scrubbing with toothbrushes gave 50.0 +/- 46.0 microg of DNA and simple rinses 34.4 +/- 35.7 microg, although the DNA was considerably degraded. DNA specimens obtained from buccal cells were shown to be more or less in the process of degradation including apoptosis. For minisatellite analysis, only DNA prepared by scrubbing with toothbrushes could be used, while all specimens could be applied to PCR analyses. Since scrubbing with toothbrushes is painless and harmless, we recommend this method. Subsequent rinsing will yield a large amount of DNA suitable for many PCR analyses.

Journal Article↗
PubMed1999

Evaluation of two new STR loci 9q2h2 and wg3f12 in a Japanese population.

Two short tandem repeat (STR) loci (9q2h2 and wg3f12) have been evaluated in a Japanese population. Ten and seven different alleles were observed in 9q2h2 and wg3f12 respectively. 9q2h2 displayed simple polymorphism in tetrameric repeat structure; by contrast, wg3f12 contained variable numbers of tetrameric repeats and a 30-bp deletion/insertion polymorphism. No "interalleles" were found. The expected heterozygosities of 9q2h2 and wg3fl2 were 0.749 and 0.574, respectively. No deviation from Hardy-Weinberg equilibrium was found.

Journal Article↗
PubMed1999

Evaluation of the paternity probability on an application of minisatellite variant repeat mapping using polymerase chain reaction (MVR-PCR) to paternity testing.

Minisatellite variant repeat (MVR) mapping using polymerase chain reaction (PCR) was applied to a practical case of paternity testing to evaluate the paternity probability. In order to obtain single allele mapping by allele-specific MVR-PCR, three flanking polymorphic sites for each of the MS31A and MS32 loci were investigated and all three individuals were typed as heterozygous for at least one flanking polymorphic site at each locus. Allele-specific MVR-PCR was then performed using genomic DNA. It was confirmed that one allele in the child was identical to that from the mother and the other one in the child was identical to that from the alleged father. Mapped allele codes were also compared with those in the database by dot-matrix analysis, and no identical allele was found although some motifs were shared with Japanese alleles. The paternity index and the probability of paternity exclusion in the case at these two MVR loci were calculated using the presumed values of the allele frequencies. These studies seem to illustrate the practical value of MVR mapping of MS31A and MS32 loci in paternity testing.

Journal Article↗
PubMed1999

Purification of nuclear DNA from single hair shafts for DNA analysis in forensic sciences.

The typing of nuclear DNA from hair shafts has often been unsuccessful to date. We tried to type one of the nuclear DNA loci, HLA-DQA1, from hair shafts, using an efficient cetyl-trimethyl ammonium bromide (CTAB) precipitation for DNA purification and a sensitive semi-nested PCR. After thorough washing with ethanol and water, hair shafts were digested by proteinase K in the presence of dithiothreitol, followed by a purification step including CTAB-DNA precipitation. The specific region of HLA-DQA1 gene was amplified by the semi-nested PCR, and the amplified products were cloned and sequenced. The HLA-DQA1 genotype was determined by comparing the sequence to the known sequence of each allele. All genotypes of HLA-DQA1 were successfully typed with hair shafts from six known heterozygotes, although one of them showed the predominant appearance of one allele. For correct typing, a template DNA equivalent to a hair shaft of 5 or 10 cm in length was necessary. Without the CTAB-DNA precipitation step, DNA extract from such hair shafts inevitably contains enough melanin to inhibit PCR. The present results suggest that hair shafts can be used for the typing of nuclear DNA loci.

Journal Article↗