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Biomedical subjects

M Tamura

Publications and source records attributed to M Tamura.

At least 505 records · Page 28Linked to original sources
PubMed1994

Small gliomas: metabolism and blood flow.

Eight patients with small gliomas (6 low-grade and 2 high-grade) localized in a single gyrus or less than 2 cm diameter were investigated using positron emission tomography and single photon emission computed tomography. All three tumors examined demonstrated hypermetabolism of amino acids. High-grade gliomas demonstrated hypermetabolism of glucose and high blood flow, but normal or low oxygen metabolism. High-grade gliomas also showed accumulation of 201Tl chloride and high or low accumulation of 123I-isopropyl iodoamphetamine. These indications allow preoperative diagnosis of the malignancy of small gliomas, which is important because small gliomas with high-grade malignancy need more extensive removal and adjuvant therapy.

Adult↗
PubMed1994

Adsorption of salivary proteins to the surface of oral streptococcal cells.

Oral tissues, especially tooth surfaces, are covered with a layer of salivary proteins. Oral bacterial cells that adsorb to salivary components accumulated on the tooth surface are, as a rule, covered with the same components, especially proteins. Thus, it is possible that the salivary proteins covering the bacterial cells are related to the adhesion of bacteria to oral tissues. The aim of this study was to clarify the mechanisms of adsorption of salivary proteins to the surface of Streptococcus sanguis, S. mitis and S. salivarius using an adsorption assay with salivary proteins labeled with tritiated formaldehyde. The results showed that salivary proteins adsorbed more to S. salivarius than to S. mitis, and least to S. sanguis. It was evident that hydrophobic bonding was involved in the adsorption of salivary proteins to the bacterial cells tested. The amount of salivary proteins adsorbed to S. mitis and S. salivarius was decreased by the presence of phosphate, that to S. sanguis was increased by the presence of a divalent cation such as Ca2+, and that to all bacteria tested was inhibited in different ways by the presence of sugars. The amount of salivary proteins adsorbed to S. sanguis and S. salivarius was reduced effectively by pretreatment of the cells with trypsin, chymotrypsin and papain. In the case of S. mitis, the amount of adsorbed salivary proteins was decreased by pretreatment of the cells with chymotrypsin only, and was increased by pretreatment with lipase. These results indicate that there are different mechanisms of adsorption of salivary protein to the cell surfaces of oral streptococci.

Acetylglucosamine↗
PubMed1994

Primary structure of bovine interstitial collagenase deduced from cDNA sequence.

Interstitial collagenase (EC 3.4.24.7, MMP-1) is a member of a family of metalloproteinases and is though to play a role in extracellular matrix remodeling. We have isolated and sequenced a cDNA for bovine interstitial collagenase from a periodontium fibroblast cDNA library. An insert of the cDNA we isolated was 2,025 bp containing an open reading frame which encodes a sequence of 469 amino acids. The identity at the amino acid level between bovine and human interstitial collagenase was 88%, between bovine and rabbit 85% and between bovine and porcine 87%. However, sequence similarity of mouse and rat interstitial collagenases to that of bovine was revealed 55%.

Amino Acid Sequence↗
PubMed1994

[Distribution of NADPH diaphorase-positive nerves in human penile tissue].

Recently, nitric oxide (NO) has been thought to be a neuronal messenger to evoke penile erection. NO synthase (NOS)-containing nerve fibers were identified and localized in human penile tissue, but detail distribution of NOS-containing nerve fibers in the human penis was unclear. In the present study we examined their distribution using histochemical staining of NADPH diaphorase (ND), which is a specific marker of neuronal NOS. In the crura penis some various sizes of ND-positive nerve bundles were observed in the cavernous spaces. In the penile shaft large bundles (> 50 microns) decreased in number and were observed only near deep artery. There were abundant ND-positive nerve terminals with fine varicosity innervating both corpus cavernous smooth muscles and deep, dorsal and helicine arteries. In the wall of deep dorsal vein there were also many groups of ND-positive fibers. Endothelium of deep artery and its large branches was clearly ND-positive, but parts of endothelium of deep dorsal vein or corpus cavernous sinus were only faintly stained. Some of the dorsal penile nerve fibers were ND-positive. In corpus spongiosum many ND-positive nerve fibers were observed and urethelium was clearly ND-positive. In conclusion, NO may have an important role in the function of both corpus cavernosum and corpus spongiosum because NOS-containing nerve fibers were widely distributed in both cavernous tissues.

Amino Acid Oxidoreductases↗
PubMed1994

[Neovascularization in experimental retinal venous obstruction in rabbit].

Experimental retinal venous obstruction was produced in rabbit eyes by transadventitial instillation of thrombin for the purpose of studying the late stage of histopathological changes in the retina. Three months after the instillation, abnormal vessels and compensatory shunt vessels were observed by ophthalmoscopy. Capillary obstruction, blood leakage from venules and neovascularization were observed on gelatin-fluorescein injected flat preparations of the retina three months after the thrombus formation. Although venular lumina were first narrowed and restored to normal three months after thrombin instillation, the lumina of arterioles remained narrow and intraluminal fibrin thrombi were present in the arterioles more than three months later in light microscopy. In electron microscopy many ribosomes and large nuclei were observed in newly formed retinal vessels, and their basement membranes were thin and discontinuous. Ghost vessels penetrated by glial cell processes were also found in the proliferative tissues. These results suggest that neovascularization occurs when the intraretinal damages last more than 3 months after the onset of thrombogenesis.

Animals↗
PubMed1994

[Antibacterial activities of a carbapenem antibiotic, biapenem (L-627), against penicillin-resistant Streptococcus pneumoniae].

Antibiotic susceptibilities were evaluated for 48 strains of Streptococcus pneumoniae collected in 1992-1993 at Ichihara City of Chiba Prefecture. Twenty two (46%) of the 48 strains were benzylpenicillin (PCG) insensitive or resistant (PRSP) judged from the MICs of PCG to higher than 0.1 microgram/ml. MICs of piperacillin and cefotaxime increased as the MICs of PCG increased. However, elevations of MICs of imipenem and biapenem (L-627) were small in spite of the increases of MICs of PCG. L-627 was effective in a case of purulent meningitis due to PC-insensitive S. pneumoniae. Thus, L-627 is a candidate to be used in treatment of PRSP infections including purulent meningitis.

Humans↗
PubMed1994

Changes of the bromodeoxyuridine labeling index of astrocytic tumors between primary and recurrent lesions.

Changes of bromodeoxyuridine labeling index at recurrence were examined in 6 glioblastomas, 2 anaplastic astrocytomas, and 3 fibrillary astrocytomas. Decreased labeling index occurred in 5 glioblastomas, probably due to the effects of combined radiotherapy and chemotherapy, but was not correlated with a favorable outcome. No change of labeling index occurred in 1 anaplastic astrocytoma. Increased labeling index was seen in 1 glioblastoma, 1 anaplastic astrocytoma, and 3 fibrillary astrocytomas, possibly indicating rapid progression just before surgery for recurrent tumor. Recurrent astrocytomas had become anaplastic astrocytoma or glioblastoma, but demonstrated no specific histopathology or labeling index of the primary lesion.

Adult↗
PubMed1994

[Seasonal variation in intraocular pressure].

Generally speaking, physicians have the impression that intraocular pressure (IOP) in winter is higher than in summer, but it is very difficult to evaluate the difference between summer and winter IOP statistically, because the treatments of glaucoma patients are changed according to their conditions. We compared the winter and summer IOP of normal subjects and of several glaucoma patients who had no therapy or no change in therapy. The subjects were divided into four groups, i.e., 20 eyes of the normal group, 17 eyes of the ocular hypertensive group, 24 eyes of the primary open angle glaucoma group, and 52 eyes of the low tension glaucoma group. The difference in mean IOP between summer and winter were evaluated for each subject. In all groups, the mean difference in mean winter IOP was significantly higher. The ups and downs of IOP were greater in the ocular hypertensive group and the primary open angle glaucoma group than in the normal group and the low tension glaucoma group. These results suggest that the seasonal variation of IOP should be taken in consideration when treating glaucoma patients.

Adult↗
PubMed1994

[Assessment of osteoporosis in the local population by means of a portable dual energy X-ray absorptiometry unit].

We assessed bone mineral density (BMD) in the local population by means of a portable dual energy X-ray absorptiometry (DXA) unit. BMD was measured by DXA in 197 women (62 premenopausal and 135 postmenopausal) in Shiunji town. Age, height, weight, body mass index (BMI), menstrual history, obstetric history, habits, symptoms and hormonal cytology (eosinophilic index (EI), karyopyknotic index (KPI) and maturation value (MV)) were investigated. A negative correlation (r = -0.645, p < 0.01) was found between BMD and age. Low BMD (BMD < 0.8g/cm2) was found at a rate of 3.2% in premenopausal women and 51.1% in postmenopausal women. The low BMD group of postmenopausal women had significantly lower BMI and higher age at first delivery than the normal BMD group (BMD > or = 0.8g/cm2). There were no differences between the 2 groups in other factors. We found a positive correlation between BMD and hormonal cytology (KPI and MV). These findings suggest that the rate of osteopenia in postmenopausal women is high than expectation and it is difficult to predict bone loss by symptoms, history and habits. The portable DXA unit is useful for screening osteopenia in local populations.

Absorptiometry, Photon↗
PubMed1994

[Three cases of hypersensitivity pneumonitis caused by inhalation of spores of Pholiota nameko and the background of the disease].

Here we report a new type of hypersensitivity pneumonitis caused by inhalation of spores of Pholiota nameko. P. nameko is a kind of mushroom which is of Japanese delicacy. Among people who are working in nameko cultivation, we found three patients suffering from hypersensitivity pneumonitis, and identified that it was caused by inhalation of spores of P. nameko. Every patient was engaged in indoor nameko cultivation inside a building equipped with a air and moisture conditioning system for two to ten years. In the indoor environment, it was thought that they were exposed to and inhaled a high density of nameko spores. Among 15 healthy indoor nameko growers, we found 6 who had precipitating antibody against extracts from nameko spores; however, there were no antibody positive people in 17 outdoor nameko growers. As seen in dairy farmers, it was clarified that there is a percentage of precipitin positive nameko growers who are asymptomatic. This is concrete evidence that changes of mushroom cultivation style can induce a new type of hypersensitivity pneumonitis. These findings were considered to be an important experience from the view points of environmental pulmonary diseases and industrial medicine.

Adult↗
PubMed1994

[Multiple cooperative study of UFT-adjuvant chemotherapy for malignant tumor in the jaw and oral cavities. The Oral Surgery Malignant Tumor Research Association in Kanto Kohshinetsu District].

We studied the usefulness and safety of long-term administration of uracil and tegafur (UFT) after primary therapy of the malignant tumor in jaw and oral cavity regions randomized controlled trial. 112 cases were totallized 6 institutes belonging to the Oral Surgery Malignant Tumor Research Association in Kanto Kohshinetsu District during 2 years and 10 months, beginning in September 1986. After completing the primary therapy, treatment was not performed in group A and 400 mg/day of UFT was orally administered in group B for 1 year. A variation was observed in the stages of background factors such as sex and age (more than 30 years old and less than 80 years old), while no such discrepancy was observed in other stages. No significant difference of 1-year-survival ratio and non-recurrence ratio was noted in either group, while the non-recurrence ratio was more favorable in group B than group A, and the usefulness of UFT for adjuvant chemotherapy was suggested. The incidence of side effects in group B was 42.6%, and no serious side effect was observed.

Adenocarcinoma↗
PubMed1994

Doppler echocardiographic evaluation of left ventricular output and left ventricular diastolic filling changes in the first day of life.

The aim of this study was to evaluate the changes in Doppler transmitral flow patterns during the 1st d of life. Doppler echocardiography of the ascending aorta and mitral valve was performed serially in 20 normal neonates at 2, 12, and 24 h of age. A computer-interfaced digitizer pad was used to measure the following: ascending aorta flow velocity-time integral, total diastolic filling flow velocity-time integral, flow velocity-time integral of early diastolic filling, and flow velocity-time integral of atrial contraction. The inner diameter of the ductus arteriosus was 4.2 +/- 0.6 mm at 2 h of age, 2.3 +/- 0.5 mm at 12 h of age, and had closed in 17 of 20 neonates (85%) by 24 h of age. The ascending aorta flow velocity-time integral and total diastolic filling flow velocity-time integral, which were high at 2 h of age, decreased significantly at 12 h of age [12.2 +/- 2.1 cm versus 9.6 +/- 1.7 cm (p < 0.001) and 8.0 +/- 1.1 versus 7.1 +/- 1.4 (p < 0.01), respectively] but remained constant thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Output↗
PubMed1994

[Trigeminal neurinoma in the cavernous sinus revealed by intratumoral hemorrhage: a case report].

A case of trigeminal neurinoma located in the left cavernous sinus and revealed by intratumoral hemorrhage is reported. Preoperatively, magnetic resonance imaging provided the accurate localization of the lesion, allowing precise planning of the surgical approach. The neurinoma inside the cavernous sinus wall was removed successfully, and the patient developed no new neurological deficits except for anesthesia in the 1st division of the trigeminal nerve. The characteristic findings of magnetic resonance imaging of the trigeminal neurinoma in the cavernous sinus are reported.

Adult↗