Biomedical subjects

S Kitazawa

Publications and source records attributed to S Kitazawa.

At least 37 records · Page 2Linked to original sources

PubMed1997

A metal halide light source for laboratory curing of prosthetic composite materials.

A high-intensity laboratory photo-curing unit has been developed with the aim of improving the post-curing properties of composite veneering materials. This study introduces the structure of the curing unit and examines the resulting properties of a representative composite material. The curing unit is equipped with two metal halide lamps that radiate both ultraviolet and visible light. Unlike conventional metal halide lamps for industrial use, these metal halide lamps radiate an increased intensity of visible radiation. Properties of a microfilled composite veneering material cured with the new metal halide unit were ascertained. A xenon photo-curing unit was also used as a control. The specimens cured with the metal halide unit exhibited greater Knoop hardness numbers and flexural moduli as compared with those cured with the xenon unit, and also showed reduced water solubility values. These results suggest that the metal halide light source is effective in curing composite materials within a shorter period of time and with improved conversion.

Analysis of Variance↗

PubMed1997

Role of alternative splicing of the rat erythropoietin receptor gene in normal and erythroleukemia cells.

An alternatively splicing of the rat erythropoietin receptor (EpoR) gene was identified in normal and erythroleukemia cells by the reverse transcription PCR method. Insertion of a 105 bp fragment at the region corresponding to the extracellular domain of rat EpoR was found. The insert sequence, which encodes additional 21 amino acids, is similar to that previously found in the mouse EpoR gene, however, has an additional 27 bp direct repeat. Due to the presence of a stop codon in the insert, the alternative transcript is translated to a truncated and soluble form of EpoR which is preferentially expressed in liver, spleen, kidney, heart, and bone marrow cells as well as cultured erythroleukemia cells. These findings suggest that alternative splicing of the EpoR gene may play an important role in proliferation and differentiation of rat erythroid cells.

Alternative Splicing↗

PubMed1996

Molecular characterization of a novel cancer cell line established from human carcinoma in pleomorphic adenoma (CaPA-4).

A cultured cell line (CaPA-4), derived from an undifferentiated carcinoma in a pleomorphic adenoma of the submandibular gland, was established through xenografted tumors in nude mice. Geneticin treatment eliminated surrounding mouse fibroblasts and yielded enriched tumor cells at an early stage of cell passage. In vitro, the line grew in a cobblestone pattern, revealing its epithelial origin. Chromosomal analysis by Giemsabanding confirmed its human origin, while electron microscopic examination showed its squamous-cell characteristics. CaPA-4 cells stained positive for the c-myc and Ha-ras antibodies. Molecular analysis showed over-expression of both c-myc and Ha-ras mRNA, with point mutation of p53 at codon 248 and of Ha-ras at codon 61. Amplification and rearrangement of the Ha-ras gene were observed; however, no loss of heterozygosity (LOH) of the p53 gene was detected by Southern blotting. This sequence of cancer-related gene activation may represent the malignant transformation from benign pleomorphic adenoma. This report describes the establishment and molecular characterization of this novel cell line from carcinoma in pleomorphic adenoma exhibiting squamous-cell differentiation. This could represent a useful model for investigating the cause of malignant transformation from human salivary-gland mixed tumors.

Adenoma, Pleomorphic↗

PubMed1996

Molecular cloning and characterization of human bone morphogenic protein (BMP)-5 gene promoter.

The bone morphogenic proteins (BMPs) constitute a novel subfamily of the transforming growth factor type beta (TGF-beta) supergene family and play a critical role in modulating mesenchymal differentiation and inducing the processes of cartilage and bone formation. In this study we isolated the 5'-flanking region of the human BMP-5 gene. Nucleotide sequencing, primer extension, DNase I foot printing and functional analysis by transient expression showed that the cloned 1.5 kb promoter region contains two transcription start sites, a canonical TATA box (-17 approximately -12) and a number of consensus recognition sequences including GATA-1 (-582 approximately -576) and engrailed (-549 approximately -541).

Base Sequence↗

PubMed1996

Convergence of skin reflex and corticospinal effects in segmental and propriospinal pathways to forelimb motoneurones in the cat.

The organization of facilitatory convergence from cutaneous afferents (Skin) and the corticospinal tract (pyramidal tract, Pyr) in pathways to forelimb motoneurones of mainly distal muscles was studied in anaesthetized cats by analysing postsynaptic potentials (PSPs), which were spatially facilitated by combinations of stimuli to the two sources at different time intervals. Conditioning Pyr volleys facilitated Skin-evoked PSPs of fixed (1.2-3.6 ms) central latencies (Skin PSPs), suggesting that disynaptic and polysynaptic skin reflex pathways are facilitated from the pyramidal tract. The shortest latencies (1.2-1.7 ms) of pyramidal facilitation suggested direct connection of pyramidal fibres with last order neurones of skin reflex pathways. Conditioning Skin volleys facilitated Pyr-evoked PSPs of fixed, mostly disynaptic latencies (1.0-2.5 ms; Pyr PSPs), suggesting that pyramido-motoneuronal pathways are facilitated from Skin at a premotoneuronal level. The shortest pathway from skin afferents to the premotor neurones appeared to be monosynaptic. Although Pyr and Skin volleys were mutually facilitating, the facilitation curve of Pyr PSPs and that of Skin PSPs were discontinuous to each other, with the peak facilitation at different Skin-Pyr volley intervals. Transection of the dorsal column (DC) at the C5/C6 border had little effect on the latencies or amplitudes evoked by maximal stimulation and the pyramidal facilitation of Skin PSPs. In contrast, the facilitation of Pyr PSPs by Skin stimulation was greatly decreased after the DC transection, and the facilitation curve of Pyr PSPs was continuous to that of Skin PSPs, with no separate peak. Latencies of Pyr PSPs ranged similarly to those in DC intact preparations. More rostral DC transection (C4/C5 border) reduced Skin-facilitated Pyr excitatory PSPs (EPSPs) less than C5/C6 lesions, suggesting that the C5 segment also contains neurones mediating Skin-facilitated Pyr EPSPs. The results show that convergence from skin afferents and the corticospinal tract occurs at premotor pathways of different cervical segments. We suggest that corticospinal facilitation of skin reflex occurs mostly in the brachial segments and Skin facilitation of cortico-motoneuronal effects takes place largely in the rostral cervical segments and partly in the brachial segments.

Animals↗

PubMed1996

Ovarian fibromatosis with minor sex cord elements.

Ovarian fibromatosis is very rare, and the one with focal proliferations of sex cord type elements is extraordinarily rare. A 31-year-old patient developed the bilateral ovarian enlargements and complained of lower abdominal pain, Pathology indicated that these tumors were ovarian fibromatosis with minor sex cord elements. Our two-step operation involved the first right salpingo-oophorectomy for histological examination and the subsequent enucleation of the left ovarian tumor alone. The patient conceived 10 months after operation.

Abdominal Pain↗

PubMed1996

Ovarian small cell carcinoma with K-ras mutation: a case report with genetic analysis.

A rare case of ovarian small cell carcinoma is reported. Laboratory examination of a 46-year-old woman with a lower abdominal tumor showed marked hypercalcemia. Her condition deteriorated progressively, and she died one month after admission. A right ovarian tumor, 8 cm in diameter, metastases to multiple organs, and intraperitoneal bleeding were confirmed by autopsy. Microscopically, the small tumor cell had rounded nuclei with small distinct nucleoli and a scanty cytoplasm. Small cell carcinoma was diagnosed from these histological features and the clinical course associated with hypercalcemia. Immunohistochemical studies showed positive staining of neuron specific enolase (NSE) and keratin. Genetic analysis using DNA extracted from paraffin sections of metastatic lesions revealed mutation of K-ras codon 12. Loss of heterozygosity of the p53 and adenomatous polyposis coli (APC) genes was not informative. Previous reports have shown that ras gene mutations occur in 30% of epithelial ovarian tumors and significantly more frequently in mucinous than in other types of ovarian tumors. These results suggest that small cell carcinoma is of epithelial origin and may have a genetic alteration similar to that of mucinous tumors.

Base Sequence↗

PubMed1996

Integrin alpha V beta 3 expression by bone-residing breast cancer metastases.

Breast cancer metastasis to bone is a multistep process requiring attachment of tumor cells to the bone and bone marrow environment. The precise adhesion molecules involved in skeletal homing of breast cancer to bone are unknown but likely include integrins. We investigated the expression of vitronectin receptor (alpha V beta 3) by breast cancer cells residing in bone because this heterodimer mediates osteoclast-bone recognition. We used immunohistochemistry and in situ hybridization in a systematic study of 22 bone biopsies containing breast cancer metastases and available samples of corresponding primary tumors and normal breast and compared alpha V beta 3, alpha 2 beta 1, and alpha B beta 5 integrin expression. The results showed that alpha V beta 3 was strongly expressed by normal breast epithelium and was decreased in some and strongly expressed in other primary invasive breast carcinomas. In contrast, this integrin heterodimer was abundant in all breast cancer cells metastatic to bone. In situ hybridization revealed high levels of steady-state mRNA corresponding to sites of protein expression; alpha 2 beta 1 was weakly expressed in both primary and metastatic tumors, and alpha V beta 5 was not detected. Our results showed an overexpression of alpha V beta 3 by bone-residing breast cancer cells and suggest either subclonal selection of alpha V beta 3-expressing tumor cell populations or upregulation of alpha V beta 3 in the bone microenvironment.

Biomarkers, Tumor↗

PubMed1996

K-ras gene mutation in gall bladder carcinomas and dysplasia.

Epithelial dysplasia of gall bladder is an important precancerous lesion of gall bladder carcinogenesis. To investigate the frequency of K-ras gene mutation in gall bladder carcinoma and dysplasia, K-ras codon 12 mutations were investigated by the polymerase chain reaction/restriction enzyme based method following direct sequencing. Mutation was detected in 59% (30 of 51) of gall bladder carcinomas, in 73% (8 of 11) of gall bladder dysplasia in gall stone cases, and in 0% of the normal gall bladder epithelium. There was, however, no correlation between K-ras mutation and clinicopathological factors of gall bladder carcinoma. K-ras gene mutation occurs even in gall bladder dysplasia at an incidence similar to that in carcinomas, suggesting that testing for K-ras gene mutation may prove useful as an adjunct to bile cytological or biopsy analysis.

Base Sequence↗

PubMed1996

Enzymatic synthesis of 4-O-beta-D-galactopyranosyl-moranoline and 3-O-beta-D-galactopyranosyl-moranoline by using beta-galactosidase from Bacillus circulans.

A transgalactosylation reaction from lactose to moranoline (1-deoxynojirimycin) was accomplished by using beta-galactosidase [EC 3.2.1.23] from Bacillus circulans. The enzyme formed 3-O-beta-D-galactopyranosyl-moranoline and 4-O-beta-D-galactopyranosyl-moranoline as major products, together with 2-O-beta-D-galactopyranosyl-moranoline and 6-O-beta-D-galactopyranosyl-moranoline as minor ones.

1-Deoxynojirimycin↗

PubMed1995

Interleukin-4 induces expression of the integrin alpha v beta 3 via transactivation of the beta 3 gene.

Osteoclastic bone resorption is dependent upon cell-matrix recognition. This process is mediated by the integrin alpha v beta 3 whose expression is enhanced, in avian osteoclast precursors, by bone-seeking steroids. The purpose of this study was to determine if bone-modulating cytokines impact on alpha v beta 3 expression by mouse marrow macrophages (BMMs), known to differentiate into osteoclasts. Of the cytokines tested. Interleukin-4 (IL-4) is most effective in increasing beta 3 mRNA levels by a mechanism involving transactivation of the beta 3 gene. Moreover, IL-4 augmented beta 3 mRNA is mirrored by plasma membrane appearance of alpha v beta 3. As IL-4 induces beta 3 and not alpha v mRNA, the beta 3 chain appears to regulate surface expression of the heterodimer. The functional significance of IL-4-induced alpha v beta 3 is underscored by the fact that, while attachment to fibronectin is unaltered, treatment of BMMs with the cytokine enhances alpha v beta 3-mediated binding to vitronectin 5-fold. Expression of this heterodimer by BMMs driven along a non-osteoclastic lineage suggests alpha v beta 3 may play a role in the inflammatory response of macrophages.

Animals↗

PubMed1995

Tuberculosis health education. Needs in homeless shelters.

Tuberculosis has reemerged as an important public health concern, particularly with the rise in multi-drug-resistant strains. The homeless are at increased risk for infection, for active disease, and for incomplete treatment. Public health authorities have recommended that tuberculosis health education materials be developed specifically for residents and staff of homeless shelters. In this study, a diverse sample of 20 adult homeless-shelter residents responded to open-ended questions regarding 1) their knowledge of tuberculosis and tuberculosis screening and treatment, 2) their perceptions of access to health care services related to tuberculosis, and 3) their views of health education regarding tuberculosis. The majority of the subjects had limited knowledge of tuberculosis and of screening and treatment for the disease. Many had misconceptions about the disease, particularly regarding its transmission. An analysis of the subjects' responses within the framework of the Health Belief Model indicated that basic tuberculosis health education programs for residents of homeless shelters are needed. The study findings indicated that a small-group educational format utilizing written materials and video aids might be most effective.

Adolescent↗

PubMed1995

Effect of the angiotensin-converting enzyme inhibitor alacepril on ventricular function and beta-adrenoceptor number in rabbits with aortic regurgitation.

This study was performed to determine the effects of the angiotensin-converting enzyme inhibitor alacepril on hemodynamic variables and beta-adrenoceptor number in rabbits with heart failure induced by aortic regurgitation. Aortic regurgitation was induced by perforation of the aortic valve in 12 rabbits. Sixty mg/kg of alacepril was administered by gastric tube for 7 days after manifestation of aortic regurgitation to 6 rabbits (group AR + A). The other 6 rabbits with aortic regurgitation were administered vehicle in the same fashion (group AR + C). Seven rabbits underwent sham operation (group S). One week after induction of aortic regurgitation left ventricular end-diastolic pressure was higher and cardiac output was lower in AR + C than in S. End-diastolic and end-systolic left ventricular diameter were larger and left ventricular weight was also higher in AR + C than in S. For each of these parameters, the opposite findings were obtained from a comparison of AR + A and S. Myocardial beta-adrenoceptor density and norepinephrine content were reduced in AR + C, but were restored in AR + A. These findings indicate that alacepril has beneficial effects on ventricular remodeling and function, and on sympatho-neuronal regulation in the volume-overloaded myocardium.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1995

Effects of delayed visual information on the rate and amount of prism adaptation in the human.

Accurate reaching towards a visual target is initially disturbed when the visual field is displaced by prisms, but recovers with successive trials. To determine how the improvement depends on the visual error signals associated with the motor output, the time course of prism adaptation was studied with delayed visual information on the error. Subjects were trained to reach rapidly at a target on a tangent screen. Vision was always blocked during the movement, and allowed again only after the index finger touched the screen. One experiment consisted of three sets of 30 trials. In the first set, the subject wore no prisms and vision was allowed without delay. In the second, the visual field was displaced by prisms, and vision was available only after a delay period of 0-10,000 msec while the subjects maintained their final pointing position. Initially, the subject misreached the target by about the amount of visual displacement (60 mm). Errors decreased with trials by an amount proportional to the error in the preceding trial. The rate of decrease of error was generally largest when the delay was 0 msec, became significantly smaller when the delay was 50 msec, and showed only gradual change with longer delays. In the third set, the subject wore no prisms and vision was allowed without delay. Initial misreaching in the direction opposite to the visual displacement, reflecting the amount of adaptation in the second set, was generally largest with no delay (median of 46 mm) and significantly smaller with 50 msec and longer delays (17-33 mm).(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗

PubMed1995

Development of skeletal metastases.

Skeletal metastases result from a series of complex steps including activation of osteoclasts and interaction between adhesion molecules on cancer cells and bone matrices. Researchers of this study used pathologic specimens of breast cancer cells from primary and metastatic sites obtained at surgery or autopsy to demonstrate the expression of parathyroid hormone-related protein by immunohistochemistry and beta 3 integrin by in situ hybridization to clarify the role of tumor-derived osteoclast activating factors and adhesion molecules in the development of skeletal metastases. The results of this retrospective study showed a significant difference of parathyroid hormone-related protein and beta 3 integrin expression in cases with and without skeletal metastases. These expressions were enhanced or clonally selected or both in skeletal metastatic sites. Because activation of osteoclastic bone resorption by parathyroid hormone-related protein could facilitate tumor cells to attach to the eroded bone surface through cell adhesion molecules, these 2 factors could make it easier for tumor cells to grow in bone.

Adult↗

PubMed1995

[Sex-related differences in EEG coherence in normal young adults--evaluation during rest and photic stimulation].

EEG coherence is a noninvasive technique for studying functional relationships between brain regions. Although EEG coherence would be a useful method to explore the differences in cerebral functional organization between the sexes, sex differences in coherence have not been well documented. The present study was conducted therefore to examine sex differences in interhemispheric EEG coherence during rest and photic stimulation (PS) in 15 male and 15 female healthy young adults. Interhemispheric coherence of the resting EEG revealed no significant sex differences for any frequency band. In contrast, coherence during PS revealed significant sex differences, and the females had a significantly higher coherence than the males in the frequency band (4.5-5.5Hz) corresponding to 5Hz PS. In addition, the changes in interhemispheric coherence from rest to the stimulus condition (i.e., coherence reactivity) showed sex differences at the brain region primarily involved in visual functioning; the females had significantly greater coherence reactivity for O1-O2 in EEG during PS at 5 and 15Hz. These findings indicate sex differences in interhemispheric EEG coherence during PS, and provide further evidence that sex-related differences exist in the degree of lateralization of hemispheric function.

Adult↗

PubMed1995

[Ethosuximide].

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Adult↗

PubMed1995

DNA resynthesis and binucleated metamorphosis in cardiac muscle cells after isoproterenol-induced injury: bromodeoxyuridine immunohistochemistry.

In this study, we assessed reactive DNA synthesis in mouse cardiac myocytes after injury in vivo using the Bromodeoxyuridine (BrdU) immunohistochemical method and clarified binucleated metamorphosis of S-phase cardiac myocytes in the myocardial healing process. The animals were injured by isoproterenol i.p., and studied 0, 1, 2, 3, 5 and 10 days after injury. Each animal was killed 3 hr after labeling with BrdU i.p. The BrdU labeling index was calculated 0, 1, 2, 3, 5 and 10 days after injury. Moreover, we observed the morphological difference of S-phase cardiac myocytes between Group A and Group B (A and B group were killed 3 hr and 3 days, respectively, after BrdU i.p.). Most of BrdU positive cells were mesenchymal fibroblastic, and BrdU positive cardiac myocytes were a minor phenomenon during healing process. In cardiac myocytes, the BrdU labeling index is 0.49 +/- 0.02 and 0.05 +/- 0.01 at day 3 and 0 after injury, respectively (P < 0.05). All BrdU positive cardiac myocytes were located around myocardial necrosis. All BrdU positive myocytes in Group A were mononucleated, whereas some were binucleated in Group B. These results indicated that some of the cardiac myocytes could synthesize DNA reactively even after birth, and that in a healing process, myocytic DNA synthesis is probably followed by binucleated metamorphosis.

Animals↗