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Biomedical subjects

M Mukai

Publications and source records attributed to M Mukai.

At least 199 records · Page 11Linked to original sources
PubMed1994

Fluoride profiles in different surfaces of human permanent molar enamels from a naturally fluoridated and a non-fluoridated area.

The surfaces, sites and depths of fluoride profiles of enamel from a naturally fluoridated area (West Hartlepool, WHP, 1.9 parts/10(6) F in drinking water) and a non-fluoridated area (Leeds, LDS, < 0.1 parts/10(6) F in drinking water) were examined in detail. Using a regression curve, y = ax-b, comparisons of fluoride concentrations were made at depths of 1, 3, 5, 10, 20 and 30 microns at occlusal, middle and cervical sites of buccal, lingual, mesial and distal molar enamel surfaces. In the outermost enamels (< 10 mu in depth), fluoride concentrations tended to be lower in the occlusal sites than in the cervical sites. In interior enamels (> 20 microns in depth), the fluoride concentrations of molars from WHP were statistically higher than those from LDS, while few significant differences were found in the outermost layers. In the mesio- and disto-occlusal sites of approximal surfaces, there were some significant differences in the exponential regression coefficients of fluoride profiles between the two groups of molars.

Dental Enamel↗
PubMed1994

Phyllodes tumor of the breast containing the intracytoplasmic inclusion bodies identical with infantile digital fibromatosis.

This report illustrates a case of the phyllodes tumor of the breast with intracytoplasmic inclusion bodies that are diffusely distributed over the tumor. The inclusion bodies were identified as aggregated actin filaments by modified immunohistochemical and ultrastructural analyses. These structures are thought to be identical to those of the characteristic intracytoplasmic inclusion bodies observed in the case of infantile digital fibromatosis. To date, tumors with such intracytoplasmic inclusion bodies have been recognized exclusively as infantile digital fibromatosis. Although a few rare cases in which the infantile digital fibromatosis-like tumor occurred outside the digit or in adulthood, all these cases were in the category of fibromatosis or fibroma. This case is the first instance of the tumor containing intracytoplasmic inclusion bodies identical with the infantile digital fibromatosis other than fibromatosis or fibroma.

Actins↗
PubMed1994

[Intra-ventricular pressure gradient and systolic anterior movement of the mitral valve associated with administration of dopamine in a 91-year-old patient].

A 91-year-old woman had decreased systemic blood pressure accompanied by dyspnea and general fatigue after resection of a face tumor (Merkel cell carcinoma). Dopamine was administered to elevate systemic blood pressure, but it did not sufficiently restore the hemodynamic status. Left ventricular apical aneurysm was observed on echocardiogram. Furthermore, SAM (systolic anterior movement of the mitral valve) was observed on M-mode echocardiogram and a pressure gradient of 34.6 mmHg in the midventricular position was confirmed by continuous wave Doppler using the Bernoulli equation. After volume overload and discontinuation of dopamine, SAM completely disappeared and midventricular pressure gradient markedly decreased. Her general condition improved. Because of the narrowed outflow tract, hypercontractile state induced by beta adrenergic stimulation seemed to be one of the important factors for the genesis of SAM and pressure gradient.

Aged↗
PubMed1994

[Morphometric study of age-related changes of the spinal cord].

The relation of aging to the length of the spinal cord and to the cross-sectional area at the levels of C6 and L3 of the spinal cord was studied in 140 autopsy cases who between the age of 47 to 105 without spinal cord lesions. In addition the effect of being bed-ridden on the spinal cord was studied in 11 of 140 cases. As pathological controls, we referred to 40 autopsy cases with compression change of the cervical cord. The length of the spinal cord had no correlation with aging but had a significant positive correlation with the height of the subject. A significant decrease in the cross-sectional area of the spinal cord was observed after the age of 80, in particular at C6. However, the extent of the decrease was not as serious as that of pathological control cases. Decrease of cross-sectional area was associated with that of white matter area. In addition, effect of being bed-ridden on the spinal cord was reflected in a significant decrease of the grey matter of the lumbar cord.

Adult↗
PubMed1994

Differences in cardiac function changes between diabetic and non-diabetic hemodialysis patients.

The main cause of death in chronic hemodialysis patients is heart failure. We studied cardiac function prospectively in diabetic and non-diabetic patients who had recently been started on hemodialysis. We analyzed the mechanocardiograms and echocardiograms in addition to routine blood chemistry tests, chest X-rays, and electrocardiograms of ten hemodialysis patients at our hospital from 1989 to 1991. Ejection fraction (EF) and fractional shortening (FS) were not significantly different between diabetic patients and non-diabetic patients at the start of hemodialysis. After starting hemodialysis, EF and FS declined in diabetic patients. In contrast, non-diabetic patients did not show any changes in EF and FS during hemodialysis. The results demonstrated a poor prognosis in cardiac systolic function in hemodialysis patients with diabetes mellitus.

Adult↗
PubMed1994

[Hodgkin's disease with a giant thymic cyst].

An asymptomatic 26-year-old male was admitted to our hospital for examination of an abnormal mediastinal shadow on chest X-ray. Chest CT showed a large mass in the anterior mediastinum with marked para-aortic lymph node enlargement. The mass consisted mostly of multiloculated low-density areas surrounded by a rim of enhancing parenchymal tissue. Both the cystic tumor and surrounding lymph nodes were resected. The tumor measured 18 x 10 x 2 cm and contained about 450 ml of straw colored fluid. Pathological examination revealed a thymic cyst, the wall of which was composed of Hodgkin's lymphoma cells and nodular sclerotic lesions containing many lacunar cells and Reed-Sternberg cells.

Adult↗
PubMed1994

Cavernous lymphangioma of the thorax: MRI findings.

Cavernous lymphangiomas of the thorax are extremely rare. We encountered an 11-year-old boy with such a disorder. Magnetic resonance imaging (MRI) showed numerous small rounded and tubular structures within the mediastinal mass; we believe these represent dilated lymphatic channels.

Child↗
PubMed1993

Okadaic acid inhibits glucocorticoid-induced apoptosis in T cell hybridomas at its late stage.

Glucocorticoids induce apoptosis in murine T cell hybridomas. It was inhibited by okadaic acid and calyculin A, potent inhibitors of protein phosphatase 1 and 2A, but not by 1-norokadaone, a structural analog of okadaic acid without phosphatase inhibitory activity. The inhibitory effect of okadaic acid was significant even when it was added 9 h after the start of the culture. Okadaic acid did not prevent either the translocation of glucocorticoid receptor from the cytoplasm to the nucleus or the induction of luciferase activity in the T cell hybridoma transfected with a plasmid containing the luciferase gene under the control of glucocorticoid response elements. These results indicate that protein dephosphorylation is an essential step for glucocorticoid-induced apoptosis in T cell hybridomas, and that the step is at the late stage of the apoptotic process.

Animals↗
PubMed1993

Induction of in vitro tumor cell invasion of cellular monolayers by lysophosphatidic acid or phospholipase D.

Serum is known to be required for invasion or phagokinesis of certain tumor cells, although the mechanism of its action is not well understood yet. In the in vitro invasion assay system we have developed, MM1 cells exhibiting extensive invasiveness against cultured mesothelial cell monolayers in the presence of 10% fetal calf serum did not invade them without serum. Human small cell lung cancer (OC10) cells also required serum in invasion. Serum could be completely substituted by oleoyl-lysophosphatidic acid (LPA) or bacterial phospholipase D (PLD). Phosphatidic acid also had an invasion-inducing activity, though to a lesser degree. Since human ovarian cancer (RMUG-S) cells require neither serum, LPA nor the PLD for invasion of mesothelial cell monolayers, the production of phospholipid like LPA, a candidate for intracellular second messenger, in tumor cells seems critical for the invasion by MM1 cells or OC10 cells. This result suggests a possible participation of particular signaling cascade, PLD-LPA(PA) system, in the invasion of certain tumor cells.

Animals↗
PubMed1993

Breast masses with mixed cystic-solid sonographic appearance.

Retrospective analysis was performed for 56 breast masses with mixed cystic and solid sonographic patterns encountered in the last 5 years at Keio University Hospital, with the objective of elucidating their significance. The lesions were classified into two major groups: tumor with cyst (TWC--solid mass with cystic component) and intracystic tumor (ICT--cystic mass with solid component). According to the pathological diagnosis, 57% were benign and 43% were malignant. Fifty eight percent of malignant lesions were shown to have a TWC pattern and 42% an ICT pattern. Among benign lesions, 66% were shown to be TWC and 34% ICT. In malignant tumors, 96% of the cases showed irregular shape and heterogeneous internal content. Even in benign lesions, a high incidence of irregular shape and rough border was found, although the predominant internal echo texture was homogeneous, and three-dimensional (3-D) contour was not clear. In conclusion, we observed that in the TWC group, the lack of a defined 3-D contour is the most important criterion, and tumors with multiples cysts tend to be benign.

Adult↗
PubMed1993

Retraction of cultured endothelial cell monolayer by human breast cancer cells, MCF-7.

A human breast cancer cell line (MCF-7), when sealed on confluent bovine pulmonary aortic endothelial cell (CPAE) monolayers, induced morphological changes (retraction) in CPAE cells. The area of retraction depended on the incubation time and the number of MCF-7 cells, suggesting that MCF-7 cells had the capacity to retract CPAE cells. This capacity was reduced by 60% by pretreatment of MCF-7 cells with 17 beta-estradiol (E) and progesterone (Pg). The extent of retraction was not affected by the addition of various protease inhibitors. CPAE retraction was induced also by adding conditioned medium (CM) from the culture of MCF-7 cells. Considerably less activity was detected in the CM obtained from MCF-7 cells cultured in the presence of E and Pg. The retraction was reversed in 24 h by culturing the monolayer in fresh medium without CM and was not induced by trypsin treatment of the CM.

Breast Neoplasms↗
PubMed1993

Bone-like nodules formed in vitro by rat periodontal ligament cells.

The periodontal ligament has been shown to possess the ability to regenerate both new cementum and alveolar bone as well as a self-regenerative capacity; however, the source of cementoblasts and osteoblasts is not still clear. We investigated the development of bone-like tissue in vitro by periodontal ligament cells, in order to determine whether the periodontal ligament contains osteoprogenitor cells. Periodontal ligament cells were obtained from periodontal ligament tissue attached to the maxillary incisors of 6-week-old WKA rats by means of the explant technique. Cells at passage #3 were cultured for long term in alpha-minimum essential medium containing 10% fetal bovine serum, antibiotics, and 50 micrograms/ml ascorbic acid, and were then examined using phase-contrast microscopy, histochemistry, transmission electron microscopy, X-ray microanalysis, and electron diffraction. Nodules were formed in the cultures, and when 10 mM Na-beta-glycerophosphate was added, these nodules became mineralized. The mineralized nodules were identified as bone-like elements in view of the presence of osteoblast-like and osteocyte-like cells, collagenous matrix, a mineral composed of hydroxyapatite, and intense alkaline phosphatase activity. The results show that the periodontal ligament contains osteoprogenitor cells, which differentiate into osteoblasts and produce bone-like tissue.

Animals↗
PubMed1993

Fluoride uptake in human dentine from glass-ionomer cement in vivo.

The purpose was to examine F uptake and distribution in dentine from a F-containing glass-ionomer cement in vivo. Nine volunteers were selected from dental students who were scheduled for extraction of their third molars. Two cavities were prepared on the same occlusal surface of the third molars for each subject; one was restored with glass-ionomer cement (Virtabond), the other with zinc phosphate cement as a control. After 3 months the teeth were extracted. F profiles in the dentine from the cavity floor to the pulpal surface were determined in tissue immediately adjacent to the restorations. An abrasive micro-sampling technique was used. The F concentration of the dentine was highest immediately beneath glass-ionomer cement filling, decreasing towards the pulpal surface. Overall F concentrations were greater in the dentine beneath the glass-ionomer cement than in that beneath the zinc phosphate cement. It was concluded that the glass-ionomer cement markedly enhanced fluoride uptake by underlying dentine in vivo.

Adult↗
PubMed1993

Biocompatibility of tetracalcium phosphate cement when used as a bone substitute.

We evaluated the biocompatibility of tetracalcium phosphate (4CP) cement, made of 4CP powder and 40 wt% copolymer of polyacrylic acid/itaconic acid and 10 wt% citric acid solution. Light and electron microscopic characteristics were studied 3, 10 and 30 d after implantation. Neither inflammation nor foreign-body giant cell reaction was observed in the tissue adjacent to the implanted material. After 30 d, this material was surrounded with newly formed bone. Ultrastructural examination showed that osteogenesis occurred directly on the surface of the material. These findings suggest that this 4CP cement is biocompatible and possesses osteoconductive properties.

Animals↗
PubMed1993

Deep body temperature during the warming phase of cardiopulmonary bypass.

We have compared deep body temperature (DBT) measured at the forehead with the core temperatures of the nasopharynx, oesophagus and rectum during the warming phase of cardiopulmonary bypass (CPB) (moderate hypothermia of 26.7-29.6 degrees C) in 12 patients. DBT was measured transcutaneously by an insulated thermistor probe that created an area of zero thermal flow between skin and subcutaneous tissue. The core temperatures measured at different sites lagged behind the increase in arterial blood temperature during warming. The trend was most marked with rectal temperature and least with oesophageal temperature. Among all measurements, the closest linear relationship was found between forehead DBT and nasopharyngeal core temperature (0.99 x nasopharyngeal temperature (degrees C) -0.07; SEE = 0.53; r = 0.99; P < 0.0001). Forehead DBT measurement may be useful as a reliable non-invasive method of monitoring cerebral temperature during CPB.

Adult↗
PubMed1993

Malignant epithelioid schwannoma of the skin showing partial HMB-45 positivity.

A malignant epithelioid schwannoma occurred on the right second toe of a 30-year-old Japanese man. It was a firm, flesh-colored, benign-appearing nodule and measured 13 x 9 mm in diameter and 6 mm in height. To our knowledge, this is the first case of malignant epithelioid schwannoma occurring on the toe. Histopathology was characterized by a circumscribed nodule in the dermis that predominantly consisted of atypical large epithelioid cells with some spindle cells whose proliferation was similar to that of the Verocay bodies seen in ordinary schwannoma. Fontana-Masson staining demonstrated no melanin pigment in the tumor at the light microscopic level. The eosinophilic cytoplasm contained abundant glycogen and was positive for S-100 protein and HMB-45, as usually seen in melanomas. Electron microscopy revealed that there was an abundance of long-spacing collagen in the extracellular matrix, and the cells contained numerous dense-cored granules. But no definite melanosomes were observed in any stage. As far as we are aware, this is the first case of a malignant epithelioid schwannoma showing HMB-45 positivity.

Adult↗