Biomedical subjects

M Kobayashi

Publications and source records attributed to M Kobayashi.

At least 109 records · Page 6Linked to original sources

PubMed2003

Histological changes and involvement of apoptosis after photodynamic therapy for actinic keratoses.

BACKGROUND: Photodynamic therapy (PDT), which employs a combination of a tumour-localizing photosensitizer and visible light, has been used to treat superficial malignancies in the epidermis. OBJECTIVES: To examine histological changes and the role of apoptosis in lesions of actinic keratosis (AK) after PDT using 5-aminolaevulinic acid (ALA) and excimer dye laser. METHODS: After topical ALA-PDT, biopsy specimens were collected from 18 skin lesions in 15 patients with AK. Paraffin-embedded sections of the skin specimens were stained with haematoxylin and eosin. The detection of apoptosis was performed using a terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labelling (TUNEL) method, antiactivated caspase-3 antibody and anti-Fas antibody. RESULTS: One hour after PDT, cells with eosinophilic cytoplasm and markedly stained nuclei were found, and vacuolation of some tumour cells was noted in the lower layer of the epidermis. An infiltrate of lymphocytes and neutrophils was observed in the upper layer of the dermis. One day after PDT, all layers of the epidermis exhibited slightly degenerative necrosis, with shadow cell formation and chromatin condensation around the nuclear membrane in the lower layer of the epidermis. Necrosis in all layers of the epidermis and lymphocyte infiltration in the dermis were found 3 days after PDT. Tumour cells had disappeared and regenerative thickening of the epidermis was observed 7 days after PDT. TUNEL staining revealed apoptosis-positive cells in the epidermis in 8 of 11 specimens obtained 1 day after PDT. Activated caspase-3 expression was noted in the lower layer of the epidermis in four of these eight TUNEL-positive specimens. CONCLUSIONS: Results suggested that apoptosis is involved in tumour cell death after PDT in patients with AK, and that it occurs within 1 day after PDT.

Aged↗

PubMed2003

Glomerular crescents predominantly express cadherin-catenin complex in pauci-immune-type crescentic glomerulonephritis.

AIMS: To investigate the expression of the cadherin complex in human crescentic glomerulonephritis to elucidate the role of intercellular adherens junction molecules in crescent formation. METHODS AND RESULTS: Immunostaining revealed cadherin complexes localized in Bowman's epithelial cells, but not in podocytes, of normal human glomeruli. Eight adult cases with myeloperoxidase anti-neutrophil cytoplasmic autoantibodies (MPO-ANCA)-related (pauci-immune type) crescentic glomerulonephritis were examined on immunofluorescence microscopy with anti-pan cadherin, p120 catenin, and beta-catenin antibodies. The specimens provided six cellular crescents, 12 fibrocellular crescents, and four fibrotic crescents. Immunofluorescence was semiquantitatively estimated by the rate of the field of localization within the whole area of the crescent, according to the four-grade system [(-) - (++)]. All the tested molecules consisting of the cadherin complex were abundantly observed in cytokeratin-positive epithelial components in crescents, each with an equivalent area of localization. The expression of the cadherin complex was closely associated with that of cytokeratin and both diminished as the crescents developed from cellular to fibrotic. CONCLUSIONS: The cadherin-catenin complex is a specific marker of Bowman's epithelial cells in human glomeruli. The cellular crescents in pauci-immune-type crescentic glomerulonephritis possess adherens junction molecules, indicating a principle parietal epithelial cell phenotype.

Adherens Junctions↗

PubMed2003

Characterization of JNK-like protein derived from a mosquito cell line, C6/36.

When Western blot analysis of heat-killed bacteria- and lipopolysaccharide (LPS)-treated Aedes albopictus mosquito cell line C6/36 was performed using antiphospholyrated c-Jun amino-terminal kinase (JNK) antibodies, approximately 46 kDa protein was clearly detected with a peak around 30 min. After the C6/36 cells were incubated at 45 degrees C in order to induce apoptosis, the 46 kDa protein continued to be detected for at least 3 h. The internalization of fluorescein-labelled bacteria was inhibited by a JNK-specific inhibitor SP600125, suggesting that phagocytosis involves the JNK signalling pathway in mosquito cells. Based on these results, we found one candidate for the nucleotide sequence of JNK (Ae-JNK) from the C6/36 cells. This study is the first report regarding the mitogen-activated protein kinase (MAPK) of mosquito.

Aedes↗

PubMed2003

Involvement of the JNK-like protein of the Aedes albopictus mosquito cell line, C6/36, in phagocytosis, endocytosis and infection of West Nile virus.

We recently cloned a c-Jun amino-terminal kinase (JNK) sequence from the C6/36 cell line, derived from the mosquito Aedes albopictus. We showed that SP600125, an inhibitor of JNK proteins, inhibits phagocytosis by C6/36 cells, suggesting that the JNK-like protein regulates phagocytosis. Here, we show that C6/36 cells constitutively express low levels of mRNA encoding the antibacterial peptides, cecropin and defensin, but that these mRNAs were up-regulated upon stimulation by lipopolysaccharide (LPS). Thus, the C6/36 cells have properties similar to those of mammalian macrophages. To characterize further the functional properties of C6/36 cells, we have assayed the role of the JNK-like protein in phagocytosis, endocytosis, and viral infection. C6/36 cells phagocytosed bacteria and artificial beads, and this was only slightly up-regulated following LPS stimulation, suggesting that newly stimulated JNK-like protein was not necessary for phagocytosis. SP600125 inhibited the acidification of intracellular compartments, including those involved in the endocytic pathway. Pretreatment of C6/36 cells with SP600125 or bafilomycin A1, but not cytochalasin D, inhibited the entry of West Nile virus (WNV), suggesting that WNV is internalized mainly by endocytosis, and that the JNK signalling pathway is important for endocytic entry. These findings indicate that the JNK-like protein regulates basic physiological functions, including phagocytosis and endocytosis and infection of WNV.

Aedes↗

PubMed2003

Primary malignant mixed mesenchymal tumour of the heart in a dog.

A case of primary malignant mixed mesenchymal tumour of the heart in an 8-year-old golden retriever is described. The cardiac tumour, measuring 2.5 x 3 x 5 cm, was located in the posterior part of the atrial septum, extending into the surrounding region. Histologically, the tumour was composed of multiple mesenchymal elements of fibrosarcoma, rhabdomyosarcoma, liposarcoma and chondrosarcoma. No previous reports of such a tumour occurring in the heart of the dog were found in the literature.

Animals↗

PubMed2003

Presence of functional domains in NADPH-dependent cytosolic 3,5,3'-Triiodo-L-thyronine (T3)-binding protein (p38CTBP) molecule: analyses with deletion mutants.

Functional domains required for NADPH-binding, T(3)-binding, protein dimerization and cytosolic retention were analyzed in NADPH-dependent cytosolic 3,5,3'-triiodothyronine (T(3))-binding protein (p38CTBP) by using the deletion mutants. Wild-type p38CTBP (amino acids; 1-314) and a series of deletion mutants (amino acids; 1-79, 1-128, 1-146, 1-216, 37-314, and 1-145 with 270-314) were bacterially induced. NADPH-dependent T(3)-binding activity was not observed in all mutant p38CTBPs studied, although wild-type p38CTBP showed high-affinity T(3)-binding activity. Wild-type p38CTBP was able to bind a CL-6B column, none of the mutant p38CTBPs showed any binding activity. Pull-down analyses demonstrated that two regions between amino acid 128 and 146, and between 216 and 270, both of which possess helical structures, were required for homodimeric p38CTBP binding. In fluoroscopic studies, GFP-tagged p38CTBP was preferentially observed in cytoplasm. However, C-terminal region-deleted p38CTBP(1-216) was not only observed in cytoplasm, but also in nucleus. These results suggest that 1) multiple regions in p38CTBP molecule are required for T(3)-binding and NADPH binding, 2) two helical structures in p38CTBP molecule may be important in the homodimer formation, and 3) C-terminal region of p38CTBP contains the function to preserve the protein in cytoplasm.

Animals↗

PubMed2003

Effect of calcium antagonist on cerebral blood flow and oxygen metabolism in patients with hypertension and chronic major cerebral artery occlusion: a positron emission tomography study.

To evaluate the effect of a calcium antagonist, nilvadipine, on cerebral blood flow and oxygen metabolism, we prospectively examined five ischaemic stroke patients, with both hypertension and chronic major cerebral artery occlusion, using positron emission tomography. The blood pressure showed a significant decrease after 3 months of nilvadipine treatment, the cerebral blood flow in the affected regions showed a significant increase and the oxygen extraction fraction showed a significant decrease. We conclude that nilvadipine is a safe and effective anti-hypertensive agent for patients with both hypertension and chronic major cerebral artery occlusion.

Aged↗

PubMed2003

Two cases of superficial basaloid squamous carcinoma of the esophagus.

. Basaloid squamous carcinoma of the esophagus is very rare. We report two cases of basaloid squamous carcinoma of the esophagus. Both tumors histologically consisted of solid cell nests with intervening fibromyxoid stroma. In some tumor nests were comprised of pseudoglandular structures containing myxoid matrix, and displayed focal immunoreactivity for laminin. Thoracic esophagectomy with lymph node dissection was followed by intrathoracic esophagogastrostomy in both patients. The patients had uneventful postoperative courses. Regular periodic follow-up showed no evidence of recurrence or metastasis in the 22-month postoperative period.

Carcinoma, Squamous Cell↗

PubMed2003

Surgical correction of cor triatriatum dexter in a dog under extracorporeal circulation.

A shiba inu dog with marked abdominal distension was diagnosed with cor triatriatum dexter and surgical correction was performed under extracorporeal circulation. The total duration of cardiac arrest was 11 minutes and total perfusion time was 34 minutes. The dog had an uneventful postoperative recovery. Postoperative contrast radiography of the caudal vena cava revealed normal flow into the right heart. Abdominal distension was no longer observed. Although several methods have been used to treat cor triatriatum dexter in dogs, the authors consider surgical correction under extracorporeal circulation to be a reliable approach.

Animals↗

PubMed2003

Subcutaneous phaeohyphomycosis caused by Veronaea botryosa in the People's Republic of China.

The second case of phaeohyphomycosis caused by Veronaea botryosa in China, in a 12-year-old boy from Jiangsu Province, is presented. Based on direct examination of the scrapings from crusted lesions; histologic examination of the biopsy tissue showing septate, phaeoid hyphal elements; and the culture exhibiting sympodial, conidiogenous cells producing predominantly two-celled, cylindric conidia, the etiologic agent was identified as V. botryosa.

Child↗

PubMed2003

Adjustment of the occlusal vertical dimension in the bite-raised guinea pig.

In humans, the inappropriate occlusal vertical dimension (OVD) causes several orofacial disorders, such as bruxism and pain in the masticatory muscles and temporomandibular joint. However, it is still unclear how strictly the OVD is adjusted. To answer this question, we studied the temporal change of the OVD in bite-raised young guinea pigs. The OVD was raised by fixation of a bite-raising appliance to the lower incisors, and increased by either 3 or 1.5 mm at the first molars. After the space produced between the upper and lower molars was filled within 10 days due to eruption of the molars, the appliance was removed. In the bite-raised animals, the raised OVD was reduced until it attained that observed in the control animals, after which the OVD increased according to cranial growth. These results show that the OVD is developmentally changed and strictly controlled.

Adaptation, Physiological↗

PubMed2003

An involvement of trigeminal mesencephalic neurons in regulation of occlusal vertical dimension in the guinea pig.

Although the occlusal vertical dimension (OVD) is strictly controlled, the neuronal mechanism of its regulation is still unclear. We hypothesize that neurons in the trigeminal mesencephalic nucleus (MesV) play an important role in the regulation of the OVD, because the MesV receives the projection from jaw-closing muscle spindles and periodontal mechanoreceptors. We measured the temporal OVD change in the guinea pig to study the effects of MesV lesions on the OVD. OVD-raised animals without MesV lesions showed a rapid OVD decrease to the same level as that in naïve controls, followed by an OVD increase after the OVD-raising appliance was removed. In contrast, OVD-raised animals with MesV lesions showed only a slight decrease in the OVD for 15 days after removal of the appliance, and then the OVD increased. The time-course of OVD development in normal-bite animals with MesV lesions was similar to that of naïve controls. These results suggest that MesV neurons are involved in OVD regulation.

Animals↗

PubMed2003

Analysis of temporal changes in the expression of estrogen-regulated genes in the uterus.

In order to understand early events caused by estrogen in vivo, temporal uterine gene expression profiles at early stages were examined using DNA microarray analysis. Ovariectomized mice were exposed to 17beta-estradiol and the temporal mRNA expression changes of ten thousand various genes were analyzed. Clustering analysis revealed that there are at least two phases of gene activation during the period up to six hours. One involved immediate-early genes, which included certain transcription factors and growth factors as well as oncogenes. The other involved early-late genes, which included genes related to RNA and protein synthesis. In clusters of down-regulated genes, transcription factors, proteases, apoptosis and cell cycle genes were found. These hormone-inducible genes were not induced in estrogen receptor (ER) alpha knockout mice. Although expression of ERbeta is known in the uterus, these findings indicate the importance of ERalpha in the changes in gene expression in the uterus.

Animals↗

PubMed2003

Similarities and differences in uterine gene expression patterns caused by treatment with physiological and non-physiological estrogens.

Administration of physiological and non-physiological estrogens during pregnancy or after birth is known to have adverse effects on the development of the reproductive tract and other organs. Although it is believed that both estrogens have similar effects on gene expression, this view has not been tested systematically. To compare the effects of physiological (estradiol; E2) and non-physiological (diethylstilbestrol; DES) estrogens, we used DNA microarray analysis to examine the uterine gene expression patterns induced by the two estrogens. Although E2 and DES induced many genes to respond in the same way, different groups of genes showed varying levels of maximal activities to each estrogen, resulting in different dose-response patterns. Thus, each estrogen has a distinct effect on uterine gene expression. The genes were classified into clusters according to their dose-responses to the two estrogens. Of the eight clusters, only two correlated well with the uterotropic effect of different doses of E2. One of these clusters contained genes that were upregulated by E2, which included genes encoding several stress proteins and transcription factors. The other cluster contained genes that were downregulated by E2, including genes related to metabolism, transcription and detoxification processes. The expression of these genes in estrogen receptor-deficient mice was not affected by E2 treatment, indicating that these genes are affected by the E2-bound estrogen receptor. Thus, of the many genes that are affected by estrogen, it was suggested that only a small number are directly involved in the uterotropic effects of estrogen treatment.

Animals↗

PubMed2003

Off-pump reconstruction of pseudoaneurysm of the descending thoracic aorta.

We report 2 cases of postoperative pseudoaneurysm of the descending thoracic aorta, repaired successfully by temporary bypass graft without extracorporeal bypass. One patient presented with a large recurrent pseudoaneurysm that developed 30 years after ligation of a patent ductus arteriosus. The other patient presented with a pseudoaneurysm 18 years after thoracic aortic reconstruction for a traumatic aneurysm. In both cases, a temporary bypass graft was created from a major branch of the aortic arch to the femoral artery prior to definitive reconstruction. The postoperative course was uncomplicated by organ dysfunction or neurologic deficit. Creation of a temporary bypass graft can avoid the need for cardiopulmonary bypass in selected patients. By avoiding heparin use, blood loss is decreased, especially when dense pulmonary adhesions from previous surgery are present.

Adult↗

PubMed2002

Hypoxia enhances the expression of autocrine motility factor and the motility of human pancreatic cancer cells.

The incidence of distant metastases is higher in the tumours with low oxygen pressure than in those with high oxygen pressure. It is well known that hypoxia induces the transcription of various genes involved in angiogenesis and anaerobic metabolism necessary for the growth of tumour cells in vivo, suggesting that hypoxia may also induce the transcription of metastasis-associated genes. We sought to identify the metastasis-associated genes differentially expressed in tumour cells under hypoxic conditions with the use of a DNA microarray system. We found that hypoxia enhanced the expression of autocrine motility factor mRNA in various cancer cells and also enhanced the random motility of pancreatic cancer cells. Autocrine motility factor inhibitors abrogated the increase of motility under hypoxic conditions. In order to explore the roles of hypoxia-inducible factor-1alpha, we established hypoxia-inducible factor-1alpha-transfectants and dominant negative hypoxia-inducible factor-1alpha-transfectants. Transfection with hypoxia-inducible factor-1alpha and dominant-negative hypoxia-inducible factor-1alpha enhanced and suppressed the expression of autocrine motility factor/phosphohexase isomerase/neuroleukin mRNA and the random motility, respectively. These results suggest that hypoxia may promote the metastatic potential of cancer cells through the enhanced autocrine motility factor/phosphohexase isomerase/neuroleukin mRNA expression and that the disruption of the hypoxia-inducible factor-1 pathway may be an effective treatment for metastasis.

Blotting, Northern↗

PubMed2002

Green revolution: a mutant gibberellin-synthesis gene in rice.

The chronic food shortage that was feared after the rapid expansion of the world population in the 1960s was averted largely by the development of a high-yielding semi-dwarf variety of rice known as IR8, the so-called rice 'green revolution'. The short stature of IR8 is due to a mutation in the plant's sd1 gene, and here we identify this gene as encoding an oxidase enzyme involved in the biosynthesis of gibberellin, a plant growth hormone. Gibberellin is also implicated in green-revolution varieties of wheat, but the reduced height of those crops is conferred by defects in the hormone's signalling pathway.

Crops, Agricultural↗

PubMed2002

Residuals of beta-hexachlorocyclohexane, dichlorodiphenyltrichloroethane, and hexachlorobenzene in serum, and relations with consumption of dietary components in rural residents in Japan.

To estimate levels of organochlorine residuals in the Japanese population and the contribution of dietary factors to these levels, we determined serum levels of beta-hexachlorocyclohexane (beta-HCH), hexachlorobenzene (HCB), p,p'-dichlorodiphenyldichloroethane (p,p'-DDD), 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene (p,p'-DDE) and p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT) in 41 volunteers (14 men and 27 women) in a rural area of Northern Japan. These organochlorine levels were measured using gas-chromatography mass-spectrometry. By a self-administered dietary history questionnaire, the usual dietary intake was estimated. Their median levels (range) were as follows: beta-HCH, 0.50 (0.05-1.50); HCB, 0.20 (0.02-0.70); and total DDT (p,p'-DDE + p,p'-DDT), 5.0 (0.9-31.0) ng/ml serum. Levels of p,p'-DDD were detected in only seven subjects (0.05-0.6 ng/ml serum). The beta-HCH levels were increased with rice and milk intakes, but the least squares means were not simply increased according to the quartile of the intakes. Concerning HCB, fish intake showed a borderline significant correlation (0.20, P = 0.052). In terms of total DDT, intakes of meat, fish, vegetable and milk showed a positive relationship, although none of them provided statistically significant results. No other statistically significant relation between any organochlorines and any food intakes examined was observed in this study. The present study suggests that organochlorine compounds are transported into the human body via foods in the Japanese population. Their effects on health should thus be investigated and monitored.

Aged↗