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Biomedical subjects

M Ohtaki

Publications and source records attributed to M Ohtaki.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Method of preventing hepatic artery occlusion during continuous intrahepatic arterial infusion chemotherapy of 5-FU].

A randomized clinical trial of combined use of steroids, which have a vascular endothelium-protecting action, was performed to develop a method to prevent hepatic artery occlusion during continuous intrahepatic arterial infusion chemotherapy with 5-FU. The steroid used was dexamethasone palmitate (Limethason), which has a high rate of uptake by endothelial cells. The 24 patients with advanced colorectal cancer were divided into 2 groups randomly and both were treated with 5-FU 250 mg/day by continuous hepatic arterial infusion for three weeks. The weekly dose was 5-FU 7 V (1,750 mg) adjusted to 50 ml with physiological saline in Group A and 5-FU 7 V (1,750 mg) adjusted to 50 ml with Limethason 1 A (4.0 mg of dexamethasone palmitate) in Group B. The reservoir was replaced every week. No changes in the mixture (appearance, pH, granule diameter, dexamethasone palmitate content) were observed up to one week. Hepatic arterial stenosis was observed in 8 cases in Group A (67%), but was not observed in any of the cases in Group B. The above results indicated that Limethason has a preventive effect against hepatic artery occlusion.

Anti-Inflammatory Agents↗
PubMed1997

Strain differences in the induction of intestinal metaplasia by X-irradiation in rats.

Strain differences in the susceptibility of rats to induction of intestinal metaplasia by X-irradiation were examined. The gastric regions of 5-week-old males of five inbred strains of rats (F344/NSlc, Copenhagen, Buffalo/NacJcl, and ACI/NHos) and three strains of randomly bred rats (HOS:Donryu, Slc:Wistar, Slc:SD) were irradiated with a total dose of 20 Gy X-ray given in two equal fractions at 3-day interrals. When examined after the rats were killed, 6 months after the last irradiation, the number of intestinal metaplastic crypts positive for alkaline phosphatase (ALP) was highest in the Donryu and lowest in the Copenhagen rats. Morphologically, the number of crypts with intestinal metaplasia in the glandular stomachs of Donryu, Wistar, SD, and Buffalo rats was higher than the number in ACI, F344, and Copenhagen rats. Intestinal metaplasia was more frequently observed in the pyloric than in the fundic glands. These results demonstrate that the induction of intestinal metaplasia by X-irradiation in rats is greatly influenced by the rat strain.

Animals↗
PubMed1997

Analysis of cancer mortality among atomic bomb survivors registered at Hiroshima University.

The aim of this study was to investigate the late effect on cancer mortality risk of the radiation exposure of atomic bomb survivors who comprised a study population different from that previously studied by the Radiation Effects Research Foundation (RERF). We examined survivors residing in Hiroshima Prefecture, who were followed up between 1968 and 1989 by the Research Institute for Radiation Biology and Medicine (RIRBM) at Hiroshima University. We used the dose-evaluation system known as Atomic Bomb Survivors 1993 Dose (ABS93D), which was based on the Dosimetry System 1986 for the survivors registered with RERF. The dose estimation was applied in a total of 35,123 subjects. Among survivors who had been alive for > 20 years after the bombing, the relative mortality risk of leukaemia at 1 Gy of organ dose was 2.37 (90% confidence interval: 1.36-3.39), which was significantly higher than the zero dose control group. Similarly, significantly higher risks were observed for all cancers except leukaemia, including cancers of the lung, colon and female breast. Comparison is made with RERF results regarding temporal changes in the relative risk. Although we observed slightly lower relative risks than RERF values for the cancer of the stomach and lung, and for all cancer except leukaemia, no marked trends for any cancer were observed in this study. Though there were some differences in population between RERF and RIRBM, no marked discrepancies were observed.

Adolescent↗
PubMed1997

Lymphoplasmacyte-rich meningioma with clinical resemblance to inflammatory pseudotumor. Report of two cases.

Two cases of lymphoplasmacyte-rich meningioma manifesting clinical and radiological characteristics unusual for a meningioma are reported. The patient in Case 1 was a 22-year-old man with a 9-year history of bilateral visual disturbances and recent dyspnea. An en plaque skull base mass, which was partially resected, was found at surgery to extend down from the planum sphenoidale into the spinal canal to C-5. Seven years later most of the residual mass in the spinal canal had disappeared, although a localized round tumor recurred at C2-3. The patient in Case 2 was a 24-year-old woman with an original diagnosis of clival meningioma, which recurred as multiple skull base lesions that spontaneously regressed in 10 months. These two cases and others reported in the literature indicate that lymphoplasmacyte-rich meningiomas may manifest peculiar biological behavior more typical of intracranial granulomas than of meningiomas.

Adult↗
PubMed1997

[Bronchopneumonia caused by Neisseria meningitidis--probable transmission by a family member who had been in Hong Kong].

A 22-year-old man came to our hospital complaining of bloody sputum. No abnormalities were seen on a chest X-ray film, but computed tomography of the chest showed infiltrates in the middle and lower lung fields. Neisseria meningitidis was isolated from cultured samples of naso pharyngeal secretions, from sputum, and from a sample obtained during bronchoscopy; bacterial bronchopneumonia was diagnosed. Family members were studied for meningococcal infection, and the bacterium was cultured from a nasopharyngeal smear from the patient's mother. The mother was asymptomatic. Both bacteria belonged to Group B serum group and their drug sensitivities were equal. The patient's family had been in Hong Kong, where this bacterium is endemic, for two years. They then returned to Japan and started to live together with the patient nine months before the onset of symptoms. The mother may have become infected in Hong Kong and may have passed the bacterium to her son after her return. Oral ampicillin was effective in both mother and son. Investigation of the patient's family was necessary to establish the probable route of infection and to decide on the treatment.

Adult↗
PubMed1997

[Adult bochdalek hernia after playing at a tug of war].

A 38-year-old female was admitted to Shonai Hospital with severe abdominal pain and nausea after playing at a tug of war in the athletic meeting. The X-ray film showed air above the left diaphragm, and CT scan and barium enema revealed the incarcerated transverse colon to the left thoracic cavity. Operation was performed through a thoracotomy. Because of no evidence of trauma, the case was diagnosed as adult Bochdalek hernia. Repair could be done by direct suture and her postoperative course was uneventful.

Adult↗
PubMed1997

[Direct surgical management of giant and large intracerebral aneurysms, associated with intraluminal thrombus and/or atherosclerotic thickening of aneurysmal neck].

Direct surgical management of giant or large cerebral aneurysms remains one of the most challenging topics in the neurosurgical field. Surgical results have remained unsatisfactory. We review 22 cases of large or giant aneurysms with intraluminal thrombus and/or atherosclerotic thickening of the aneurysmal neck that have received direct surgical management in our department during the period from 1984 to 1996. As initial symptoms, ten patients presented with mass effect, five with ischemic attack, and three with subarachnoid hemorrhage. Sixteen aneurysms were supratentorial and six were in the posterior fossa. Direct neck clipping was attempted in sixteen cases. Two giant basilar aneurysms among them were clipped under deep hypothermia with cardiac arrest. Simple trapping of the parent artery was performed in three aneurysms and trapping with bypass graft was also carried out in three aneurysms. Ten patients made an excellent clinical recovery. Eleven patients suffered mild to severe disability. One death resulted from brain stem infarction, not directly related with surgical management. Appropriate preoperative assessment and intraoperative management of the associated thrombus and atherosclerotic change of the aneurysmal neck are essential for obtaining acceptable surgical results of large or giant cerebral aneurysms.

Adult↗
PubMed1996

Influence of paternal (252) Cf neutron exposure on abnormal sperm, embryonal lethality, and liver tumorigenesis in the F(1) offspring of mice.

Experiments were conducted to determine whether neutron-induced genetic damage in parental germline cells can lead to development of cancer in the offspring. Seven-week-old C3H male mice were irradiated with (252) Cf neutrons at a dose of 0, 50, 100, or 200 cGy. Two weeks or three months after irradiation, the male mice were mated with virgin 9-week-old C57BL females. Two weeks after irradiation, the irradiated male mice showed an increased incidence of sperm abnormalities, which led to embryo lethalities in a dose-dependent manner when they were mated with unirradiated female mice. Furthermore, liver tumors in male offspring of male mice in the 50 cGy group were significantly increased in 19 of 44 (43.2%) animals, in clear contrast to the unirradiated group (1 of 31; 3.2%) (P < 0.01). In the 100 cGy group, 6 of 39 (15%) mice had lesions. At 3 months after irradiation abnormal sperm and embryonal lethality were not significantly increased. The incidences of liver tumors in male offspring from the 50 cGy, 100 and 200 cGy groups were 6 of 20 (30%), 5 of 22 (23%) and 1 of 19 (5%), respectively, which are not significantly increased compared with the control. It is concluded that increased hepatic tumor risk in the F(1) generation may be caused by genetic transmission of hepatoma-associated trait(s) induced by (252) Cf neutron irradiation.

Animals↗
PubMed1996

Use of the Weibull hazard model to estimate age-specific probability of permanent tooth loss.

In analysis of the probability of tooth loss with age, the exact time of tooth loss is often unknown, although it is clear whether a tooth remains or has been lost. That is, left censoring is inevitable during data sampling. This may provide a biased estimate if such data are dealt with by the product-limit method, which is a common method of survival analysis. To reduce such a bias in estimating the age-specific probability of tooth loss, we developed a survival analysis method taking left censoring into consideration. Four hundred and forty-six panoramic radiographs obtained in a daily clinical practice were used. The frequency of tooth loss with age was assumed to follow the Weibull hazard model, and a likelihood function taking left censoring into consideration was defined to estimate the probability of tooth loss. The estimate obtained from our method was compared with that from the product-limit method to examine whether the effect of left censoring was reduced. We found that the probability of tooth loss estimated by the product-limit method was biased by left-censored data, and that the bias was reduced when our method was used. A Monte Carlo simulation study, in which the true tooth loss time was given, also showed that our method provided an estimate closer to the true value. Our method is considered to be more accurate in estimating the probability of tooth loss, since it reduces the bias caused by left-censored data.

Adolescent↗
PubMed1996

Usefulness of panoramic radiography in the diagnosis of postmenopausal osteoporosis in women. Width and morphology of inferior cortex of the mandible.

OBJECTIVES: To evaluate the usefulness of width and morphology of the inferior cortex of the mandible on panoramic radiographs in the diagnosis of postmenopausal osteoporosis. METHODS: The width and morphology of the mandibular inferior cortex on panoramic radiographs were compared with trabecular bone mineral density (TBMD) of the 3rd lumbar vertebrae (L3) measured by dual energy quantitative computed tomography in 29 premenopausal and 95 postmenopausal women. RESULTS: There was a significant negative correlation between the width (Kendall's tau = -0.36, p < 0.001) and morphology (Kendall's tau = -0.49, p < 0.001) of the mandibular inferior cortex and the L3 TBMD. Regression analysis showed that significant linear relationships were observed between the L3 TBMD and age (p < 0.001), cortical width (p < 0.05), morphology (p < 0.05), controlling body mass index, number of teeth present and menopausal status (R2 = 0.42). CONCLUSION: Our results suggest that panoramic radiography could be reliable in screening for osteoporosis.

Adult↗
PubMed1996

Purification and activity of recombinant chicken stem cell factor produced by using a baculovirus vector.

Stem cell factor is a pleiotropic cytokine that plays an essential role in the development of hematopoietic cells, germ cells, and melanocytes. To obtain recombinant soluble chicken stem cell factor (chSCF), a baculovirus containing the cDNA encoding chSCF polypeptide from amino acids -25 to 170 was constructed. The chSCF produced in insect cells infected with the virus was purified by ion exchange column chromatography. The ability of the purified protein to induce the outgrowth of neurites from chicken dorsal root ganglia cultured in vitro was demonstrated.

Animals↗
PubMed1996

A case of calcification of the cervical ligamentum flavum.

We report a case of cervical myelopathy caused by the calcification of the cervical ligamentum flavum. A 42-year-old woman with gait disturbance and an episode of dysuria was transferred to our hospital on June 30, 1994. Neurological examination revealed only a mild right hemiparesis. A plain neck X-ray and a tomogram revealed a nodular calcification in the posterior part of the spinal canal at the level of C5/6. Three dimensional computed tomography clearly demonstrated that the mass consisted of three nodular structures on the vertebral lamina. Magnetic resonance images demonstrated severe compression of the spinal cord by the mass whose intensity was low. The mass was removed en bloc together with the ligamentum flavum and C5 and C6 lamina. The mass showed no continuity to the dura mater. The calcification was confined within the ligament. The patient's neurological deficits were resolved two weeks after the surgery. X-ray diffraction study demonstrated the component of the mass was found to be pure hydroxyapatite. Clinical features of calcification of the ligamentum flavum are reviewed from 85 reported cases including ours, and the difference between this calcification and the ossification of the ligament is emphasized. Calcification of the ligamentum flaum is a distinct clinical entity.

Adult↗
PubMed1996

[Surgical approach for cervical dumbbell type neurinoma: posterior approach by partial hemilaminectomy with preservation of a facet joint].

We report on a case harboring a cervical dumbbell type neurinoma. The tumor was completely removed by a modified posterior approach, consisting of partial hemilaminectomies of C2 and C3 with preservation of the facet joint. The operative field under microscope was limited by the preserved facet joint of C2/3. However, sufficient bulk reduction of the epidural and paravertebral mass enabled us to obtain a good operative field. The paravertebral mass, which extended anteriorly to just beside the posterior aspect of the carotid sheath, was removed through the lateral space. The operative field was easily widened beside the right facet joint of C2/3 with partial removal of the posterior part of the transverse process of C2 and C3. The transit portion of the tumor to the normal nerve fiber was also identified through this space. The intracanalicular mass was removed by the partial hemilaminectomies of C2 and C3 without compressing the dural sac. Following sufficient reduction of the bulk, the right vertebral artery was identified at the anteromedial margin of the enlarged intervertebral foramen. Finally the intradural part of the tumor was removed through this space. Our modified posterior approach is a less invasive method to the bony elements of the cervical vertebrae and may minimize the incidence of postoperative instability and angular deformity. This approach also eliminates the necessity of long postoperative immobilization using a rigid cervicothoracic brace.

Cervical Vertebrae↗
PubMed1996

[Distinctions of petroclival meningioma with perifocal edema on adjacent brain stem].

Although the most frequent benign tumor of the central nervous system, meningioma may be associated with extensive peritumoral edema. Whereas, peritumoral edema in the brain stem along the tumor in the infratentorial region has not been given sufficient recognition. Among 44 meningiomas attached to the petrous bone, 25 cerebellopontine angle meningiomas and 17 petroclival meningiomas, peritumoral edema in the brain stem along the tumor were clearly demonstrated on T2 weighted images of MRI in three petroclival meningiomas (6.8% of all clival and 17.6% of petroclival meningiomas). Attempts were made to surgically remove all of these tumors. However, during surgery an arachnoid/pial layer between the tumor and brain stem was destroyed completely and small perforating arteries were found to be encased in the tumor at the level of the associated edema. So surgical dissection of the tumors from the brain stem was quite difficult. By attempting radical removal of the tumor in the first case, even meticulous dissections caused direct surgical damage in the brain stem due to the obliteration of small perforating vessels. In the second case, a thin layer of the tumor remnant beside the brain stem was left intentionally, but a severe damage of the brain stem also occurred due to the obliteration of small perforating vessels. In the third case, only bulk reduction of the tumor was attempted to minimize the mass effect to the brain stem and the tumor located beside the brain stem with edema and encasing the cranial nerves and the perforating arteries from the vertebrobasilar artery was left untouched. This surgical attempt caused a transient worsening of a swallowing disturbance, but was not associated with the brain stem damage in this case. In meningiomas attached to the clivus, existence of associated peritumoral edema in the adjacent brain stem on T2 weighted images on MRI may be caused by the destruction of a arachnoid/pial layer and the encasement of small perforating vessels. The attempt at tumor dissection from the brain stem at the level of the edema was very difficult and led to serious surgical complications due to direct damage to the brain stem. In such cases, the surgery should aim at achieving a simple bulk reduction and the tumor beside the brain stem with edema should be left untouched.

Aged↗
PubMed1996

[Evaluation of carotid artery stenosis with three-dimensional CT angiography and surgical revascularization].

The accuracy of three-dimensional CT angiography (3D-CTA) for delineating atherosclerotic carotid stenosis was examined in comparison with digital subtraction angiography (DSA) in symptomatic patients. In cases undergoing carotid endarterectomy (CEA), the clinical usefulness of 3D-CTA for surgical planning was also evaluated in the light of intraoperative findings. From July 1992 to June 1995, 52 patients suffering from internal carotid ischemia and/or presenting carotid bruit were evaluated to detect carotid bifurcation stenosis by 3D-CTA. Shaded surface reconstruction (SSR) for three-dimensional display and maximum intensity projection (MIP) were employed in multiple projection to evaluate sites of stenosis. DSA was performed in 18 out of 31 patients having atherosclerotic carotid stenosis shown by 3D-CTA. MIP reconstructions accurately delineated sites of stenosis close to DSA and allowed precise depiction of ulcerated plaque and intramural calcification. The percentage of carotid stenosis was determined by comparing the narrowest point to the internal carotid artery (ICA) beyond the bulb on both 3D-CTA and DSA. Assessment of carotid stenosis was highly correlated between 3D-CTA and DSA (r = 0.987, p < 0.0001). In this series, 9 carotid arteries in 8 patients underwent CEA for severe stenosis. 3 patients with ICA occlusion and 1 patient with elongated severe stenosis underwent STA-MCA anastomosis. Using MIP reconstructions and two-dimensional original images it was found that ICA occlusion was apparently distinguished from high grade ICA stenosis. SSR provided valuable informations during CEA for atherosclerotic plaque regarding anatomical relationship with the internal jugular vein and bony structures. This advanced means of 3D-CTA can be adequate as a screening method to detect carotid stenosis in symptomatic patients and useful for surgical planning of CEA and post-operative follow-up examination.

Angiography, Digital Subtraction↗
PubMed1996

[Prognosis after total removal of craniopharyngiomas via the frontobasal interhemispheric approach].

Prognosis after total removal of craniopharyngiomas via the frontobasal interhemispheric approach is reviewed. Seventeen patients with craniopharyngiomas were operated on in Sapporo Medical University Hospital between January, 1985 and December, 1993. In eleven patients, lamina terminalis was incised and in the last six patients, it was left intact. Tumors were completely resected in all patients. After removal of the tumor, hypothalmic--pituitary functions, visual functions and psychometric functions were examined. Two of the 17 cases showed hypernaturemia and fourteen (82%) had permanent DI. Fourteen patients are receiving DDAVP and all are receiving endocrine replacement. Of fourteen patients who had disturbance of their visual acuity, nine (64%) improved. Five of six patients (83%) who presented visual field defect showed improvement in their deficits. Thirteen patients had a psychometric assessment at the time of follow-up examination. Full-scale intelligence quotient scores were distributed as follows: three above 120, five between 90 and 109, three between 70 and 79 and two below 69. Four (32%) had some impairment of memory. Concerning the QOL after total removal of craniopharyngiomas via the frontobasal interhemispheric approach, thirteen patients (76%) are leading normal lives, and three (18%) are leading nearly normal lives but require some help to overcome mild deficits. One (6%) has suffered a significant handicap.

Adolescent↗