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Biomedical subjects

H Takei

Publications and source records attributed to H Takei.

At least 37 records · Page 2Linked to original sources
PubMed2000

Combined effect of titanium particles and TNF-alpha on the production of IL-6 by osteoblast-like cells.

To clarify the role of tumor necrosis factor (TNF)-alpha on osteoblast functions in the presence of metal particles, two human osteoblast-like cell lines (MG-63 and SaOS-2) were cultured with TNF-alpha in the presence or absence of titanium particles in vitro. A combination of TNF-alpha and titanium particles showed additive effects on inhibition of cell proliferation and alkaline phosphatase production. On the other hand, production of interleukin-6, which is well known to induce osteoclastogenesis and to directly stimulate bone resorption, was additively stimulated by the combination of TNF-alpha and titanium particles. These results suggest that the association of TNF-alpha and titanium particles may play an important role in the pathogenesis of periprosthetic osteolysis through two different pathways: a reduced periprosthetic bone formation due to inhibition of osteoblast proliferation and alkaline phosphatase production, and osteoblast-mediated activation of osteoclastic bone resorption as suggested by the enhancement of interleukin-6 production.

Biocompatible Materials↗
PubMed2000

Titanium particles inhibit osteoblast adhesion to fibronectin-coated substrates.

To illuminate the effect of titanium particles on osteoblast function, we compared the adhesion force of neonatal rat calvarial osteoblasts on fibronectin-coated glass after incubation with titanium particles (80% had diameters of less than 5 microm). The cells were incubated with the particles for 1.5-72 hours. Using a micropipette single-cell manipulation system, we showed that the adhesion force of the osteoblasts to fibronectin-coated glass (1.0 microg/ml) was significantly affected by the presence of particulate debris. The adhesion force of the cells incubated with titanium particles for less than 4 hours was not significantly affected by exposure to the particles; after 4 hours, however, it was significantly reduced relative to that of controls. Aspiration of particle-challenged osteoblasts into the micropipette demonstrated that the particles were not stripped from the cell surface and therefore confirmed that the osteoblasts had ingested them. During aspiration, the particles traveled through the cytoplasm rather than on the cell surface. When the osteoblasts were exposed to the particles and cytochalasin D, they exhibited much lower adhesion forces than did the controls or the cells exposed to titanium particles only; this indicates an important role of actin filaments in the osteoblastic response to particles. Staining for F-actin also indicated an influence of internalized titanium particulate on cytoskeletal arrangement and cell spreading. Furthermore, with standard Northern blotting techniques, levels of mRNA for collagen type I and fibronectin were significantly reduced as early as 4 hours after exposure to particles compared with levels in controls, and this effect continued to 72 hours. These data indicate that direct exposure of osteoblasts to titanium particles, which we propose to be ingested by the osteoblasts, can significantly decrease osteoblast adhesion force; this may lead to decreased cellular activity and gene expression of fibronectin and collagen type I in the presence of titanium wear debris.

Actins↗
PubMed2000

Atypical cystic lobule of the breast: an early stage of low-grade ductal carcinoma in-situ.

The authors describe the characteristics of atypical cystic lobules (ACLs), which represent a step in the formation of low-grade ductal carcinoma in-situ. The authors define ACLs as a proliferation of luminal cells showing low-grade cytological atypia without architectural atypia. ACLs were compared with conventional hyperplasia, low-grade ductal carcinoma in-situ, and lobular neoplasia. 1) In about 40% of the cases, atypical cystic lobules merged with fully established micropapillary/cribriform ductal carcinoma in-situ. 2) Immunohistochemical staining for hormone receptors, keratin nineteen, and cyclin D1 revealed that atypical cystic lobules demonstrate a consistent immunophenotype, which differs from that of normal lobules and benign lesions and matches the one of low-grade ductal carcinoma in-situ. 3) ACLs are sometimes calcified. Osteopontin-positive histiocytes infiltrated all Kossa-positive (type II microcalcification) cribriform and comedo-type carcinomas and ACLs. The similarities in cytological and immunohistochemical features, the close proximity of the two types of proliferation, and the similarities with respect to calcification suggest that atypical cystic lobules represent an early stage in the formation of certain types of low-grade ductal carcinoma in-situ.

Breast↗
PubMed2000

Sudden hemorrhage of the breast caused by breast cancer: a case report and review of the literature.

A rare case of sudden hemorrhage caused by breast cancer is reported. A 71-year-old woman noted bleeding from her left breast. Physical examination of the left breast showed a localized open cavity accompanied by bleeding and coagulation. The patient had no history of breast trauma or anticoagulation therapy. Incisional biopsy followed by histological examination resulted in a diagnosis of granulation tissue with no cancer cells present. Mammography and ultrasonography indicated probable breast cancer. As a result, a second incisional biopsy was performed, which suggested invasive ductal carcinoma without histological skin invasion. A modified radical mastectomy was performed under a diagnosis of stage II breast cancer. Breast cancer with sudden hemorrhage is rare. We review the literature and discuss the cause of this unusual manifestation.

Aged↗
PubMed2000

A case report of advanced male breast cancer with an objective response to tamoxifen treatment.

A 70-year-old man presented with a firm tumor in his right breast first noticed eight years ago. The tumor had enlarged gradually and had produced an ulcer with bleeding. On physical examination, a huge tumor entirely occupied the right breast and extensively had infiltrated the chest wall. Chest X-ray and CT showed massive pleural effusion and multiple small nodular lesions in the lung. Invasive ductal carcinoma of the breast was diagnosed by incisional biopsy,confirming advanced breast cancer with lung metastases and bilateral pleural effusion(T4cN2M1, Stage IV). Because ER and PgR levels were 110 fmol/mg and 190 fmol/mg, respectively, and because his general condition was poor, we selected medical treatment with tamoxifen(TAM). Thirty-two weeks later, the tumor had showed pronounced reduction with scarring. The patient underwent local excision of the scar tissue. The quality of life of the patient was favorably improved and no severe adverse events were observed. The tumor in the chest wall recurred two months after the end of TAM treatment, possibly because the patient did not accept continuous TAM therapy. The patient died from complications of brain metastasis 32 months after the start of TAM treatment. We report a rare case of advanced male breast cancer and on the effectiveness of continuous TAM treatment.

Aged↗
PubMed2000

The distribution of oxidatively-modified lysine in the human vasculature.

Fifty-seven sections of human vessels, collected in the Pathobiological Determinants of Atherosclerosis in Youth study from individuals aged 25-34, were stained with two monoclonal antibodies to oxidatively-modified lysine. Intensity and extent of immunoreactivity were graded by three pathologists. Aorta from a Watanabe heritable hyperlipidemic (WHHL) rabbit was stained as a positive control. Intimal immunoreactivity in the rabbit was predominantly localized to lesions. Although immunoreactivity in humans was somewhat more intense in atherosclerotic plaques, substantial staining was present in intima with diffuse intimal thickening and coronary veins. Localization of oxidatively-modified lysine in humans did not correlate with localization or severity of atherosclerosis. Localization of immunoreactivity for oxidatively-modified lysine to intimal lesions in the WHHL rabbit may be due to absence of diffuse intimal thickening, which prevents retention of epitopes throughout the intima.

Adult↗
PubMed2000

The effects of calcium phosphate cement particles on osteoblast functions.

Calcium phosphate cements (CPC) are increasingly used in the orthopedic field. This kind of cement has potential applications in bone defect replacements, osteosynthetic screw reinforcements or drug delivery. In vivo studies have demonstrated a good osteointegration of CPC. However, it was also observed that the resorption of CPC could create particles. It is known from orthopedic implant studies that particles can be responsible for the peri-implant osteolysis. Biocompatibility assessment of CPC should then be performed with particles. In this study, we quantified the functions of osteoblasts in the presence of beta-TCP, brushite and cement particles. Two particle sizes were prepared. The first one corresponded to the critical diameter range 1-10 microm and the second one had a diameter larger than 10 microm. We found that CPC particles could adversely affect the osteoblast functions. A decrease in viability, proliferation and production of extracellular matrix was measured. A dose effect was also observed. A ratio of 50 CPC particles per osteoblast could be considered as the maximum number of particles supported by an osteoblast. The smaller particles had stronger negative effects on osteoblast functions than the larger ones. Future CPC development should minimize the generation of particles smaller than 10 microm.

Animals↗
PubMed2000

Primary squamous cell carcinoma of the breast during lactation: a case report.

A case of primary squamous cell carcinoma of the breast during lactation is reported. The patient was a 32-year-old woman, in post-partum lactating 18 months after delivery, who was referred to our hospital following detection of a lump in her left breast during physical examination in mass screening for breast cancer. The tumor, palpated in the upper outer quadrant of the left breast, was firm, well-defined and 2.8 x 2.6 cm in size. Ultrasonograms identified an irregular-shaped hypoechoic lesion and mammograms revealed a well-defined, circumscribed tumor. Based on these findings, breast cancer was suspected and an excisional biopsy was performed. The resected specimen was a firm, solid and circumscribed tumor with central hemorrhage. Microscopic findings demonstrated that the tumor consisted of an invasive ductal carcinoma with marked squamous metaplasia, such as keratinization and squamo-columnar junction. Breast-conserving surgery was performed and no lymph node involvement was noted. Both estrogen and progesterone receptors of the tumor were negative. Generally, the size of both squamous cell carcinoma and carcinoma during the lactation period tends to be larger than ordinary carcinomas. In this case, the cancerous lesion was detected at a relatively early stage. Although the cancerous lesion was detected at a relatively early stage and no lymph node involvement was noted, lung metastases occurred within 12 months of the surgery. Malignant potential is generally considered to be high in cases of squamous cell carcinoma of the breast with lactation and thus intensive treatment potentially resulting in severe side effects was considered to be necessary for this patient.

Adult↗
PubMed1999

The cytotoxic effect of titanium particles phagocytosed by osteoblasts.

The cytotoxic effect of different concentrations of titanium particles on osteoblasts was studied in vitro. It was found that the viability of the osteoblasts was inversely proportional to the particle concentration. Phagocytosis of particles by the osteoblasts was evident and was demonstrated to be responsible for cell necrosis. Moreover, during and after phagocytosis, the osteoblasts released products that were cytotoxic for other osteoblasts, as established with a conditioned medium assay. The titanium particles thus had both a direct and an indirect effect on osteoblast viability. It also was observed that the titanium particles induced a process of programmed cell death (apoptosis) when co-cultured with osteoblasts. The results of this study suggest that not only is the amount of wear debris generated important, but the local accumulation of the debris also may have a significant impact on bone cell function.

Analysis of Variance↗
PubMed1999

A novel glycosylphosphatidyl inositol-anchored protein on human leukocytes: a possible role for regulation of neutrophil adherence and migration.

We report here a novel glycosylphosphatidyl-inositol (GPI)-anchored glycoprotein on human leukocytes. Treatment of neutrophils with a mAb (3H9) to this molecule sequentially up-regulates and down-regulates beta2 integrin-dependent adhesion of these cells as well as their transendothelial migration in vitro. In addition, this mAb simultaneously modulates the avidity of beta2 integrin for its ligand, iC3b, with kinetics similar to those observed in 3H9 modulation of neutrophil adherence. This mAb also induces beta2 integrin-dependent cytoskeletal remodeling. This novel GPI-anchored protein (GPI-80) is highly homologous with Vanin-1, a recently reported GPI-anchored protein that is expressed on perivascular thymic stromal cells and is involved in thymus homing in mice. The finding that both GPI-80 and Vanin-1 are 40% homologous with human biotinidase suggests the existence of a biotinidase superfamily of molecules that may be involved in the regulation of leukocyte trafficking.

Actins↗
PubMed1999

Granular Cell Tumor of the Breast Diagnosed by Core Needle Biopsy: A Case Report.

Granular cell tumor rarely occurs in the breast. We report a 69-year-old woman with a right breast mass that simulated carcinoma on palpation, mammography, and ultrasonography. Aspiration biopsy cytology showed no malignant atypical cells. Core needle biopsy was performed to obtain an accurate diagnosis. The lesion was histologically confirmed to be a granular cell tumor. Immunostaining was positive for S-100 protein and vimentin, and negative for keratin, carcinoembryonicantigen, estrogen receptor and gross cystic disease fluid protein-15. The tumorwas treated by wide local excision. Surgeons should be aware that granular cell tumor can resemble breast cancer in order to avoid performing a needless radical mastectomy.

Journal Article↗
PubMed1999

The efficacy of technetium-99m-MIBI scan and intraoperative methylene blue staining for the localization of abnormal parathyroid glands.

The efficacy of the technetium-99m-2-methoxyisobutylisonitrile (Tc-MIBI) scan and intraoperative methylene blue staining was analyzed in a consecutive series of 15 patients with primary hyperparathyroidism who underwent neck surgical exploration. A total of 17 abnormal parathyroid glands were removed, 7 of which were confirmed histologically as adenomas and 10 as hyperplasias. The Tc-MIBI scan and the thallium-201-technetium-99m subtraction (Tl/Tc) scan preoperatively localized 11 (69%) of 16, and 6 (40%) of 15 abnormal parathyroid glands, respectively. The Tc-MIBI scan correctly localized two ectopic abnormal parathyroid glands which were not localized by the Tl/Tc scan or ultrasonography (US). However, it also demonstrated false-positive accumulations caused by thyroid diseases in two patients. There were 4 abnormal parathyroid glands not detected by the preoperative imaging techniques, whereas all 17 abnormal parathyroid glands were stained with methylene blue, the infusion of which caused no adverse effects or toxicity. In conclusion, Tc-MIBI scanning and intraoperative methylene blue staining are effective techniques for the localization of abnormal parathyroid glands in patients with primary hyperparathyroidism.

Adenoma↗
PubMed1999

Recurrent cardiac tamponade treated using a pericardio-venous shunt.

A 49-year-old woman was admitted because of recurrent cardiac tamponade. She had undergone radical mastectomy and radiotherapy for left breast cancer four years previously. In the following two years, she felt short of breath on exertion due to cardiac tamponade. Repeated conservative therapy with diuretics and pericardial drainage were ineffective in terminating pericardial effusion. The therapeutic procedure of a pericardio-venous shunt was then employed and was effective for improving the recurrent symptoms.

Breast Neoplasms↗
PubMed1999

Alterations of protein kinase C, 8-hydroxydeoxyguanosine, and K-ras oncogene in rat lungs exposed to passive smoking.

To investigate the effects of exposure to sidestream cigarette smoke (CS) on the initiation and promotion of lung cancer, two groups of 8 or 10 rats were exposed to CS for a 1 h period twice a day for 8, 12, or 20 weeks. The protein kinase C (PKC) activity of the lung exhibited significant changes of 120, 86 and 81% in the CS groups, compared with the respective control group values in the three exposure periods. The in vitro activation of PKC by the active oxygens was efficiently eliminated by hydroxyl radical scavengers, indicating that hydroxyl radicals are responsible for the PKC activation. For the alterations in the lung nucleus caused by passive smoking, the 12- and 20-week exposure CS groups showed significant increases in the accumulation of 8-hydroxydeoxyguanosine. One rat with K-ras activation by G:C transversion (GGT-->GCT) at codon 12 was found among 26 rats of the CS groups in the three exposure periods. These results show that active oxygens introduced by passive smoking may contribute to K-ras activation as an initiator of a tumor model, possibly through the oxygen-induced DNA damage, and may also contribute to an initial activation and the subsequent down-regulation of PKC as a promoter.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1999

Smoking and atherosclerosis in youth.

Coronary heart disease is the most common cause of death in the US. Studies have demonstrated that smoking is a major risk factor for coronary heart disease and that a positive relationship occurs between smoking and aortic and coronary atherosclerosis in adults. In 1985, a multicenter cooperative study, Pathobiological Determinants of Atherosclerosis in Youth (PDAY), was organized to study atherosclerosis in trauma victims 15-34 years of age. Reports from this study have demonstrated that smoking is strongly associated with the prevalence and extent of grossly visible raised lesions in the abdominal aorta but only weakly associated with similar lesions in the right coronary artery. Coronary arteries from 50 smokers and 50 non-smokers were classified microscopically using a system developed by the American Heart Association in order to determine the stage at which smoking affects atherosclerosis. Smokers had over twice as many advanced lesions, types IV and V, as non-smokers (32 vs 14%) and fewer early lesions, types I, II, III, as non-smokers (38 vs 62%). The prevalence of advanced or types IV and V lesions (32%) was over twice that of intermediate or type III lesions (14%) in smokers. The opposite relationship was observed in non-smokers (14 vs 26%). This observation suggest that intermediate lesions progress rapidly into advanced lesions in smokers and that intima formerly having early lesions is replaced by intima with raised lesions.

Adolescent↗
PubMed1999

Cognitive deterioration associated with focal cortical dysplasia.

Surgery for an area of focal cortical dysplasia in a critical region is reported in a right-handed female manifesting intractable focal epilepsy and verbal cognitive deterioration. She developed the first seizure at 2 years of age and was treated with phenytoin and zonisamide, with good control until 10 years of age. Although seizures did not occur at 9 years of age, she manifested dyscalculia, right-left disorientation, and finger agnosia, and N-isopropyl-p-iodoamphetamine single-photon emission computed tomography (SPECT) revealed focal hypoperfusion in the left parietal lobe. At 11 years of age, she developed regular nocturnal seizures and gradually lost the ability to understand the meaning of sentences. Verbal IQ declined from 94 to 63, and the area of hypoperfusion detected by interictal N-isopropyl-p-iodoamphetamine SPECT spread over the left parietotemporal lobes. Magnetic resonance imaging revealed focal cortical dysplasia mainly in the left parietal lobe, and ictal technetium-99m-ethyl cysteinate dimer SPECT images demonstrated an area of hyperperfusion around the focal cortical dysplasia, including the left precentral gyrus. Because of the overlap between the epileptogenic and functional cortex, the authors concluded that cortical resection, including focal cortical dysplasia, was inappropriate in this patient.

Cerebral Cortex↗