Biomedical subjects

M Kabuto

Publications and source records attributed to M Kabuto.

At least 55 records · Page 3Linked to original sources

PubMed1997

Experimental and clinical study of detection of glioma at surgery using fluorescent imaging by a surgical microscope after fluorescein administration.

Total resection is the optimal treatment for malignant gliomas. However, an unexpected residual tumor mass is sometimes found on magnetic resonance imaging performed after an operation because of a macroscopically unclear margin of the tumor at surgery. This study was designed to evaluate the effectiveness of fluorescent imaging by a surgical microscope after fluorescein administration for the detection of gliomas at surgery. For this study, we produced two filters for the excitation and emission of fluorescein that can be easily fitted to and removed from a surgical microscope manually during the operation. For the experimental study, Wistar rat brains bearing C6 glioma were removed at appropriate intervals after intravenous administration of 10-20 mg kg-1 body weight of sodium fluorescein, and their surface and coronal section through the tumor were observed using a surgical microscope with the filters. In clinical cases, 1000 mg of sodium fluorescein was intravenously administered to five patients with glioma before tumor resection. In the experimental study, the C6 glioma itself and the edematous brain adjacent to the tumor (within 2-3 mm of the gross surface of the tumor) were well stained a brilliant yellowish green for a few hours. The normal brain was not stained. In clinical cases, the tumors were stained a brilliant yellowish green under fluorescent observation at surgery. The patients had no side effects. At all times the fluorescent observation could be quickly changed to ordinary observation by removing the filters from the surgical microscope. The tumor was also stained a faint yellow under ordinary nonfluorescent observation. Although this contributed to detection of the tumor, the fluorescent staining demarcated the tumor more clearly than nonfluorescent staining. These results suggest that this imaging technique by a surgical microscope with special filters at surgery may be practical and useful for detection of gliomas and warrants further clinical evaluations.

Animals↗

PubMed1997

Fat and fiber intakes in relation to serum estrogen concentration in premenopausal Japanese women.

It has been implied that fat and fiber intakes influence breast cancer risk. The effects of these dietary factors may be mediated by hormonal changes. We evaluated the relationships between fat or fiber intake and serum concentration of estradiol (E2) or sex hormone-binding globulin in premenopausal women. In 1994 blood samples were collected from each of 50 premenopausal healthy Japanese women on Days 11 and 22 of the menstrual cycle. Nutrient intakes were assessed by food frequency questionnaire in which the subjects were asked about their diets during one year before the study. Each nutrient intake was categorized into tertile after adjustment for total energy. Linear regression models, including age and cycle length as covariates, were utilized to evaluate the association between the nutrient intakes and the hormone concentrations. A statistically significant trend was observed between increasing fat intake and increasing E2 on Day 11 of the cycle (p = 0.05). The positive trend for increasing sex hormone-binding globulin on Day 22 with fat intake was of borderline significance (p = 0.06). There was a statistically significant inverse trend for E2 on Day 11 of the cycle with fiber intake (p = 0.05). It was suggested that fat as well as fiber intake should affect the hormone status.

Adult↗

PubMed1997

Decreased serum estradiol concentration associated with high dietary intake of soy products in premenopausal Japanese women.

We examined the cross-sectional relationship of soy product intake to serum concentrations of estradiol (E2) and sex hormone-binding globulin (SHBG) in 50 healthy premenopausal Japanese women. Intakes of soy products and various nutrients were estimated through a semiquantitative food-frequency questionnaire. Blood samples were drawn from each subject on Days 11 and 22 of her menstrual cycle. The intake of soy products was inversely correlated with E2 on Days 11 and 22 of the cycle after controlling for age, body mass index, cycle length, and intakes of total energy, fat, and crude fiber (r = -0.23, p = 0.08 and r = -0.32, p = 0.04, respectively). No significant correlation was observed between soy product intake and SHBG. There was a tendency for the intake of individual soy foods such as tofu and miso to be inversely correlated with E2 on Days 11 and 22 of the menstrual cycle. Miso intake was inversely significantly correlated with SHBG on Day 22 of the cycle (r = -0.36, p = 0.02). If the observed association is causal, our results suggest that the consumption of soy products lowers the risk of developing breast cancer risk modifying estrogen metabolism.

Adult↗

PubMed1997

Factors associated with serum levels of estradiol and sex hormone-binding globulin among premenopausal Japanese women.

We measured serum levels of estradiol (E(2)) and sex hormone-binding globulin (SHBG) among 50 healthy premenopausal Japanese women in 1994 in Gifu, Japan, to investigate the relationships between potential risk factors for breast cancer and hormone levels. Using a self-administered questionnaire, we collected data on body size, physical activity, and previous disease history, as well as menstrual and reproductive histories of the woman and her mother. Blood samples were drawn from each subject on the 11th and 22nd days of her menstrual cycle. Higher serum E(2) levels were observed for women with shorter menstrual cycles. Age as well as cycle length were included in the regression models to determine the associations between hormone levels and study variables. Body mass index (BMI) was inversely related to SHBG level measured at the 11th day of the cycle, after adjusting for age and cycle length (r = -0.33; p = 0. 03). Women born in spring/summer had higher levels of E(2) on the 22nd day (p = 0.07) and higher levels of SHBG on both the 11th and 22nd days of the cycle (p = 0.01 and p = 0.06, respectively) than those born in other seasons. Physical activity at 13-15 years of age was inversely related to E(2) level on the 11th day of the cycle after controlling for age, cycle length, BMI, and birth month (r = -0.35; p = 0.04).

Adult↗

PubMed1997

[Experimental study of detection of brain tumor at surgery using fluorescent imaging under a surgical microscope after fluorescein administration].

Total resection is the optimal treatment for malignant gliomas. However, we sometimes find an unexpected residual tumor mass on magnetic resonance imaging performed after an operation because of a macroscopically unclear margin of the tumor during operation. This study was designed to evaluate the effect of fluorescein sodium on imaging of glioma in combination with a surgical microscope for detection of the tumor at surgery in a rat glioma model. For this study, we produced two filters for the excitation and emission of fluorescein that can be easily fitted to and removed from a surgical microscope manually during the operation. For the in vivo study, Wistar rat brains bearing C6 glioma were removed at appropriate intervals after the intravenous administration of 10-20 mg/kg body weight of fluorescein sodium, and their surface and coronal sections through the tumor were observed using a surgical microscope with the filters. For the in vitro study, the cultured C6 glioma cells were exposed to 5 micrograms/ml of fluorescein sodium for 2 hours and then observed by confocal laser scanning microscopy. In the in vivo study, the C6 glioma itself and the brain within 2-3 mm of the gross surface of the tumor (probably indicating part of the perifocal edema) were well stained a brilliant yellowish green for a few hours. The normal brain was not stained. The intensity of the fluorescence was dose-dependent and was stronger under the xenon than under the halogen lamp. The in vitro study demonstrated almost no uptake of fluorescein by the C6 glioma cells. This fact indicates that the fluorescein in the stained tumor exists in extracellular spaces due to the disruption of the blood-brain barrier. These results suggest that this staining technique using fluorescein sodium and a surgical microscope with special filters during the operation may be the intravenous administration of 10 useful for detection of gliomas and warrants evaluation of clinical application.

Animals↗

PubMed1997

A population study on risk factors for insomnia among adult Japanese women: a possible effect of road traffic volume.

In an effort to identify risk factors for insomnia and determine the contribution of nightime road traffic volume to insomnia in the general population, a questionnaire survey was carried out among 3,600 adult Japanese women living in eight urban residential areas. The crude prevalence rate of insomnia was 11.2%. Multivariate analysis revealed that aging, living with a child/children aged six or younger, undergoing medical treatment, experiencing major life events, having an irregular bedtime, having a sleep apnealike symptom, and living near a road with a heavy volume of traffic are risk factors for insomnia. Taking into account other risk factors, there was a level-response relationship between the nighttime traffic volume of main roads and the risk of insomnia in the subjects living in the zones 0-20 m from these roads. These results suggest that road traffic noise raises the sound level in bedrooms in such zones, and consequently the prevalence rate of insomnia among the residents, and that noise-induced insomnia is an important public health problem, at least in highly urbanized areas. To confirm this, a further study on noise exposure is needed.

Adult↗

PubMed1996

Secretion of matrix metalloproteinase-2 (72 kD gelatinase/type IV collagenase = gelatinase A) by malignant human glioma cell lines: implications for the growth and cellular invasion of the extracellular matrix.

Human glioma cells (T98G and A172 cell lines) were cultured on various extracellular matrix (ECM) components including type I, IV and V collagens, fibronectin, laminin, and reconstituted basement membrane (Matrigel), and the role of matrix metalloproteinases (MMPs) in their growth and invasion was examined. T98G glioma cells grew well on these ECM components and invaded the reconstituted basement membrane. In contrast, A172 glioma cells showed growth inhibition on collagen types IV and V and Matrigel without invasion of the Matrigel. Gelatin zymography and enzyme immunoassays demonstrated that T98G glioma cells, but not A172 cells, secrete a large amount of matrix metalloproteinase-2 (MMP-2, 72 kD gelatinase/type IV collagenase = gelatinase A), and this was confirmed by immunoblotting and immunohistochemistry. Of the two different tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2), T98G cells produced only TIMP-1 during culture on Matrigel, whereas A172 cells secreted both. Although both human recombinant TIMP-1 and TIMP-2 stimulated T98G cell growth slightly on Matrigel, the in vitro invasiveness was significantly reduced by only recombinant TIMP-2. These results suggest that MMP-2 plays an important role in the ECM invasion of T98G human glioma cells in vitro.

Brain Neoplasms↗

PubMed1996

Endothelial-cell injury of the basilar artery caused by ethanol infusion in dogs.

This study in mongrel dogs was designed to observe the effects of ethanol on both endothelial cells of the basilar artery and brain function. By use of sterile surgical technique, a super-selective catheter was placed in the proximal portion of the basilar artery in the dogs. Five dogs received 3 ml of 25% ethanol and 5 dogs received 3 ml of 50% of ethanol through the catheter over 2 minutes. The remaining 5 dogs received 3 ml of saline as a control. Auditory brain stem response (ABR) was monitored for 2 hours after ethanol infusion, and then perfusion-fixation was performed from the heart with 4% paraformaldehyde. The basilar artery was observed with scanning electron microscopy after routine procedures. The endothelial cells were intact in the control group. The 50% group showed a higher level of injury to the endothelium as well as a higher degree of platelet adhesion and fibrin clot formation compared with the 25% group. The extensive endothelial-cell damage subsequently caused thrombus formation. The ABR disappeared immediately after ethanol infusion in both ethanol groups, and recovered gradually in the 25% group, but did not re-appear during the time course of 2 hours in the 50% group. The ethanol less than 25% in concentration near the endothelium is considered to be safe as a transcatheter embolic agent with the attention to the central toxicity.

Animals↗

PubMed1996

MR imaging of cerebrospinal fluid rhinorrhea following the suboccipital approach to the cerebellopontine angle and the internal auditory canal: report of the two cases.

BACKGROUND: Cerebrospinal fluid (CSF) otorhinorrhea is one of the most common postoperative complications following the suboccipital approach to the cerebellopontine angle and the internal auditory canal. Accurate preoperative detection of the site of CSF leakage is important because inaccuracy may require a more extensive exploratory surgical procedure in the repair operation. There are few reports on evaluation of magnetic resonance (MR) imaging in diagnosing CSF leakage. CASE DESCRIPTION: MR imaging of two cases of postoperative CSF rhinorrhea is reported. A 53-year-old woman and a 29-year-old man underwent suboccipital operations for microvascular decompression of the facial nerve in hemifacial spasm and for removal of an acoustic schwannoma, respectively. In both cases, MR findings were useful in preoperatively delineating the site of the CSF leakage, which was confirmed during the repair operation. CONCLUSION: MR imaging may be useful in identifying the site of CSF leakage following the suboccipital approach to the cerebellopontine angle.

Adult↗

PubMed1996

MR imaging and CT of pituitary abscess: case report and review.

Pituitary abscess is a rare disorder. However, preoperative diagnosis is important to prevent a cranial approach leading to severe meningitis. A case of a 55 year-old woman with pituitary abcess is reported. The patient was admitted with a several-week history of frontal headache and no signs of inflammation. Computed tomographic (CT) scan showed a slightly low-density suprasellar expanding mass lesion with an enhanced thin wall in the pituitary region. Magnetic resonance imaging showed a homogenous high-intensity signal relative to brain parenchyma on T1-weighted images with an enhanced thin wall and a homogenous low-intensity signal on T2-weighted images. This was histologically shown to be a pituitary abscess. Our case and review of the available literature suggest that pituitary abscess generally shows a homogenous low-density on CT scan and a homogenous low- to iso- and high-intensity signals or homogenous high- and low-intensity signals on T1- and T2-weighted images, respectively, with a cystic appearance and enhanced smooth wall.

Brain Abscess↗

PubMed1996

Meningeal sinus histiocytosis mimicking lymphoplasmacyte-rich meningioma. Case report.

Extranodal sinus histiocytosis with massive lymphadenopathy involving the meninges is a rare clinical entity. The authors describe the unusual case of an occipital meningeal lesion in a 25-year-old man in whom they found inflammation of the occipital lobe mimicking lymphoplasmacyte-rich meningioma. The clinical similarities and differences are discussed.

Adult↗

PubMed1995

Detection of mammosomatotroph cells and identification of the coexistence of growth hormone and prolactin within the same secretory granules in these cells using confocal laser scanning microscopy.

This study was designed to examine whether mammosomatotroph cells (MS cells) can be easily detected using confocal laser scanning microscopy (CLSM) and whether the coexistence of growth hormone (GH) and prolactin (PRL) within the same secretory granule can be identified in the MS cell using CLSM. Conventional epoxy resin-embedded tissues of mixed GH- and PRL-secreting human pituitary adenomas were used for this double-labelling immunofluorescent study by CLSM. A semithin section of the tissue after plastic removal and bleaching was immunohistochemically double-stained with primary antibodies against GH and PRL, followed by secondary antibodies conjugated with Rhodamine (GH) and FITC (PRL). MS cells simultaneously showing fluorescence of both Rhodamine and FITC were easily detected by CLSM at lower magnification. At higher magnification, the coexistence of Rhodamine and FITC on the same secretory granule was identified by using a superimposed display. This finding was confirmed by immunoelectron microscopy. The CLSM technique may be useful for the study of MS cells.

Adenoma↗

PubMed1995

The influence of total body hyperthermia on brain haemodynamics and blood-brain barrier in dogs.

This study was designed to examine the influence of total body hyperthermia (TBHT) using an extracorporeal circuit with a heat exchanger on the cerebral blood flow (CBF), intracranial pressure (ICP), brain tissue pH, cerebral autoregulation and blood-brain barrier (BBB) permeability in dogs. The rectal temperature of the dow was raised to 41.5 degrees C, maintained at 41.5-42.0 degrees C for 2 hours (HT period) and then reduced to normothermia by cooling. Regional CBF was measured by the hydrogen clearance method before heating, during the HT period and after cooling. ICP and brain tissue pH were monitored during the TBHT treatment. Autoregulation of the CBF during the HT period was assessed by measuring the regional CBF and the ICP in a state of induced hypo- or hypertension. The influence of TBHT on BBB permeability was examined using an immunohistochemical technique. The regional CBF increased from 38.1 +/- 6.5 (mean +/- SD) to 49.1 +/- 9.8 ml/100 g/min and the ICP from 10.3 +/- 4.2 to 16.8 +/- 3.4 mmHg when TBHT was raised. These returned to normal values after cooling. The regional CBF and the ICP changed in parallel with drug-induced changes of mean arterial blood pressure during the HT period. These changes suggest that autoregulation of the CBF is paralysed during the HT period. Brain tissue pH decreased rapidly when the rectal temperature exceeded 41.0 degrees C. The pH was 7.18 +/- 0.05 during the HT period and was relatively stable. The pH returned to a normal value after cooling. Immunopositive stain for albumin was not observed in heated brain tissue except for the normally leaky pineal gland and the choroid plexus, indicating preservation of BBB during TBHT. These results suggest that brain oedema may occur easily due to paralysed cerebral autoregulation when the arterial blood pressure fluctuates excessively, so arterial blood pressure must be controlled strictly during TBHT.

Acid-Base Equilibrium↗

PubMed1995

Effect of mannitol on focal cerebral ischemia evaluated by somatosensory-evoked potentials and magnetic resonance imaging.

BACKGROUND: Mannitol has been used in routine neurosurgical practice for the control of increased intracranial pressure. The effect of mannitol on focal cerebral ischemia was evaluated by somatosensory-evoked potentials (SEP) and magnetic resonance imaging (MRI). METHODS: The left middle cerebral artery (MCA) was exposed via the superomedial transorbital approach and occluded proximal to the origin of the perforating arteries. Ten cats received mannitol (0.5 g/kg IV) immediately, 6, 12, and 18 hours after MCA occlusion. The other 10 cats received saline solution and served as control. The animals were initially prepared to measure SEP before and 15, 30, and 60 minutes after MCA occlusion. Following SEP measurement, all cats were prepared for MRI. Sequential MRI of both intravoxel incoherent motion (IVIM) and T2-weighted spin echo techniques were obtained at 2, 4, 6, and 24 hours after MCA occlusion. The animals were sacrificed after the last MRIs for histologic study. RESULTS: The SEP amplitude decreased to about 10% at 15 minutes after MCA occlusion and then gradually recovered to 38% at 60 minutes in the mannitol group, and 21% in the control group. In MRI study, IVIM imaging demonstrated ischemic cerebral injury as a sharply demarcated area at 2 hours after MCA occlusion, while T-2 weighted imaging failed to show clear evidence of injury until 2-6 hours. High-signal intensity areas on both IVIM and T2-weighted images were smaller in the mannitol group than those in the control group. Histologic study demonstrated that infarction size was 36.9% +/- 7.7% of the left hemisphere in the mannitol group and 57.3% +/- 5.3% in the control group (p < 0.05). CONCLUSIONS: Mannitol is effective for acute cerebral ischemia, and SEP and MRI are useful for monitoring it.

Animals↗

PubMed1995

Experimental study of intraoperative local chemotherapy with fibrin glue containing nitrosourea for malignant gliomas.

BACKGROUND: Local control of the tumor bed after removal of a tumor is one of the most important points in the treatment of malignant gliomas. This study was designed to examine whether fibrin glue is useful as a vehicle for sustained release of intraoperative local chemotherapy with nitrosourea (ACNU). METHODS: The growth-inhibiting activity of ACNU on C6 glioma cells and ACNU released into 5-mL supernatant saline from fibrin glue containing 5 mg/mL (10 mg) of ACNU was measured in vitro. C6 tumor inoculated in rat brains was covered with fibrin glue containing either 2 mg/mL or 5 mg/mL of ACNU for 5 days, and the histologic changes were examined. RESULTS: ACNU inhibited the growth of C6 glioma cells in a dose-dependent manner, and the drug concentration required for 50% inhibition of cell growth (IC50) was about 4 micrograms/mL with 1 hour of treatment. Although about 50% of all ACNU included in the fibrin glue was released in the first hour, an effective concentration over the value of IC50 was sustained even after 12 hours. A histologic examination showed tumor cells damaged within a depth of about 2-3 mm from the tumor surface covered with fibrin glue containing ACNU. CONCLUSIONS: Fibrin glue may be useful as a vehicle for sustained-release chemotherapy, and intraoperative local chemotherapy with fibrin glue containing anticancer agents such as nitrosourea may be helpful in the local control of malignant gliomas.

Animals↗

PubMed1995

The antitumor effect of MX2, a new morpholino anthracycline, against malignant glioma cell lines and its subcellular distribution.

The chemotherapeutic effect of MX2 (3'-deamino-3'-morpholino-13-deoxo-10-hydroxycarminomycin), a new lipophilic morpholino anthracycline, against rat C6 and human T98G glioma cells, was examined in vitro and in vivo. The subcellular distribution of MX2 was also studied. The drug concentrations of MX2 required for the 50% inhibition of cell growth (IC50) for C6 and T98G cells were 25.5 +/- 1.3 ng/ml and 70.6 +/- 6.8 ng/ml, respectively, which were much lower than the IC50 values for nimustine (ACNU). A C6 subline resistant to ACNU, C6/ACNU, was established by continuous exposure to graded concentrations of ACNU. The IC50 of MX2 for C6/ACNU was 28.3 +/- 2.2 ng/ml, indicating no cross-resistance to MX2. In the rats bearing the intracerebral C6 tumors, the life span was increased by about 40 to 100% after intravenous administration of MX2 at doses ranging from 1 to 3 mg/kg of body weight. Confocal laser scanning microscopy demonstrated visually the good accumulation of MX2 in the implanted intracerebral C6 tumors, as well as its predominant distribution in the cytoplasm over the nucleus in both cell lines in vitro. Ultrastructural studies also demonstrated the cytotoxic effects of MX2 against glioma cells. Our results suggest that MX2 may be a useful chemotherapeutic agent in the treatment of malignant gliomas and that confocal laser scanning microscopy is useful for the study of the cellular pharmacokinetics of anthracycline derivatives, such as MX2.

Animals↗

PubMed1995

Brain metastasis from malignant mesothelioma--case report.

A 62-year-old male presented with a rare brain metastasis from malignant mesothelioma manifesting as headache and progressive left hemiparesis. He had previously undergone pleurectomy for malignant mesothelioma. Chest x-ray films showed no recurrence of mesothelioma. Computed tomography and magnetic resonance imaging revealed a homogeneously enhanced nodular mass adjacent to the falx in the right frontal lobe. The tumor was totally removed and diagnosed histologically as brain metastasis from malignant mesothelioma. Following surgery, left hemiparesis improved gradually. Brain metastasis from malignant mesothelioma is usually discovered in the terminal stage or at autopsy. Surgical removal and radiotherapy should be considered for isolated lesions.

Brain Neoplasms↗

PubMed1995

Simultaneous bilateral hypertensive intracerebral hemorrhages--two case reports.

A 65-year-old male and an 80-year-old female presented with unusual simultaneous bilateral hypertensive intracerebral hemorrhages in the putamina and thalami, respectively. The hematomas were demonstrated by computed tomography performed within a few hours of onset. The patients underwent conservative therapy. The male patient died 4 days after the onset and the female finally became vegetative. The majority of patients with bilateral intracerebral hemorrhages generally have a poor outcome due to the development of severe disturbed consciousness, tetraparesis, and pseudobulbar palsy, even if the hematomas are not so large. The indication of surgery for this type of hemorrhage may be confined to patients with small hematomas who can be expected to have a good functional outcome after removal of the larger hematoma.

Aged↗