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Biomedical subjects

S Kitazawa

Publications and source records attributed to S Kitazawa.

At least 73 records · Page 4Linked to original sources
PubMed1997

Identification of regulatory elements of human alpha 6 integrin subunit gene.

The integrin alpha 6 subunit associates with either the beta 1 or beta 4 subunit to form receptors for laminin, a major component of the basement membrane. Here, we characterized basal promoter of the human integrin alpha 6 subunit gene. The transcription start site, mapped by primer extension analysis, was 208 bp upstream of the translation start site. The promoter region lacked canonical TATA and GC boxes, but did contain a TATA-like sequence (GATAAA) 23 bp upstream of the major transcription start site. Consensus binding sites for Sp1 and the NF-kappa B complex were also present in the promoter region. A putative glucocorticoid/progesterone receptor responsive element (GRE/PRE), together with the Ap1 and c-myc binding sites located around 350-360 bp upstream of the transcription start site, represented positive regulatory sequences. Our current study showed a molecular model by which progesterone promotes tumor cell invasion through the basement membrane by up-regulating the laminin receptor.

Antigens, CD↗
PubMed1997

Prism adaptation of reaching movements: specificity for the velocity of reaching.

Accurate reaching toward a visual target is disturbed after the visual field is displaced by prisms but recovers with practice. When the prisms are removed, subjects misreach in the direction opposite to the prism displacement (aftereffect). The present study demonstrated that the severity of the aftereffect depends on the velocity of the movements during and after the visual displacement. Trained subjects were required to reach with one of four movement durations (<300, approximately 800, approximately 2000, and approximately 5000 msec) from a fixed starting point to a target that appeared at a random location on a tangent screen (400 mm away). The size of the aftereffect was largest when the movement after the removal was performed with the same duration as that performed with the prisms. It became smaller as the difference in velocity became larger. When the contralateral arm was used after visual displacement, the aftereffect was never significant. Because the adaptation does not generalize across velocities or to the other arm, we infer that the underlying changes occur at a later stage in the transformation from visual input to motor output, in which not only the direction but also the time-dependent parameters of movements, such as velocity, acceleration or force, are represented.

Adaptation, Physiological↗
PubMed1997

Alternative splicing of the erythropoietin receptor gene correlates with erythroid differentiation in rat hematopoietic and leukemic cells.

An alternative splicing of the rat erythropoietin receptor (EpoR) gene was identified in normal and erythroleukemia cells. A 105 bp insert was found at a region corresponding to the extracellular domain of EpoR. The alternative transcript was translated to a soluble EpoR (EpoR-S) expressed in spleen, bone marrow, and cultured erythroleukemia cells in addition to the full-length EpoR (EpoR-F). One of the rat erythroleukemia sublines, K4DT, which partially lost erythroid phenotypes and manifested monocyte/macrophage characteristics also lacked EpoR-S expression. Thus, expression of EpoR-S may play an important role in differentiation of rat erythroid cells.

Alternative Splicing↗
PubMed1997

In situ detection of parathyroid hormone-related protein in ovarian clear cell carcinoma.

A case of ovarian clear cell carcinoma associated with hypercalcemia is reported. A 67-year-old woman developed the lung metastasis 8 months after primary surgery. The patient manifested symptoms of humoral hypercalcemia of malignancy (HHM) during the last 3 months of her clinical course. Serum and urinary C-terminus parathyroid hormone-related protein (PTHrP) levels were remarkably high. No increase in interleukin (IL) 1beta, tumor necrosis factor (TNF) alpha, vitamin D3 metabolites or intact PTH was detected. Pamidronate disodium treatment was transiently suppressed her serum calcium level. The patient died despite seven courses of chemotherapy. Autopsy showed multiorgan metastases and accelerated osteoclastic bone resorption; skeletal metastasis was not detected. Immunohistochemical analysis clearly showed the localization of PTHrP at both the primary and metastatic sites. The transcripts of PTHrP at pulmonary metastatic sites were revealed by in situ hybridization and the reverse transcription polymerase chain reaction (RT-PCR) method. PTHrP was the causative factor for HHM in this case. It is therefore suggested that hypercalcemia may have occurred after PTHrP production had overcome the homeostatic level during the terminal stage, although PTHrP production continued irrespective of the patient's serum calcium level.

Adenocarcinoma, Clear Cell↗
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↗