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Biomedical subjects

T Kodama

Publications and source records attributed to T Kodama.

At least 451 records · Page 25Linked to original sources
PubMed1995

Induction of VGF mRNA in neurons of the rat nucleus tractus solitarius and the dorsal motor nucleus of vagus in duodenal ulceration by cysteamine.

To investigate the possible role of the brainstem in cysteamine-induced peptic ulceration, we examined the expression of VGF mRNA, which is induced in PC12 cells following application of nerve growth factor [23], in the nucleus tractus solitarius (NTS)/dorsal motor nucleus of vagus (DMV) complex of the medulla oblongata by in situ hybridization histochemistry. In control saline-treated rats, weak VGF mRNA signals were only rarely detected in neurons of the NTS and none were observed in those in the DMV. After 12 h of cysteamine administration (450 mg/kg, s.c.), the time at which duodenal ulcer was detected in all cases, heavily labeled VGF mRNA-expressing neurons appeared in the NTS and DMV. By quantitative analysis on macroautoradiogram, the VGF mRNA signals of the NTS/DMV complex in cysteamine-treated rats were twice as much as those in saline-treated rats. In situ hybridization histochemistry combined with the use of the retrograde neuronal tracer cholera toxin-B subunit revealed that the induced VGF mRNA-expressing neurons of the DMV projected directly to the stomach. The present results suggest that ulceration accompanies the induction of VGF mRNA in neurons of vagal afferent and efferent areas of the brainstem.

Animals↗
PubMed1995

Damage to red blood cells induced by acoustic cavitation.

This experimental study has revealed damage to red blood cells that is quantitatively related to the acoustic pressure during irradiation with 0.75-MHz continuous-wave ultrasound, using a range of intensities comparable to those employed by ultrasonic physiotherapy equipment (0.25 to 7 W cm-2 spatial average temporal average). Damage to the red blood cells was investigated by measuring the extent of haemolysis using a UV/VIS spectrophotometer. There was a clear correlation between the amount of haemoglobin released and the intensity of harmonic emissions recorded from the sample during irradiation. The observed degree of haemolysis could not be produced by temperature rises in the absence of the sound field. This suggests that the damage was a direct result of acoustic cavitation.

Acoustics↗
PubMed1995

The cavitation threshold of human tissue exposed to 0.2-MHz pulsed ultrasound: preliminary measurements based on a study of clinical lithotripsy.

Evidence of acoustic cavitation was identified in the form of transient echoes in ultrasound B-scan images of patients receiving extracorporeal shock-wave lithotripsy treatment on a Storz Modulith SL20. This lithotripter generates 10-microseconds duration pulses with a centre frequency of 0.2 MHz at a pulse repetition frequency of 1 Hz. The visual appearance of B-scan images was examined in a total of 30 patients and a quantitative analysis of echogenicity changes was carried out in six cases involving lithotripsy treatment of stones in the renal pelvis. In these patients new echoes were identified in images unaffected by movement artefacts and were found to occur in perinephric fat and adjacent muscle and kidney tissue at positions close to the axis of the shock-wave field between 1 and 2 cm in advance of the indicated beam focus of the lithotripter. The echogenicity within each region increased significantly above the background level when the output of the lithotripter was increased above a threshold value. The acoustic pressures corresponding to this threshold were measured in water using a calibrated PVDF membrane hydrophone. After correction for attenuation in tissue the cavitation thresholds, in terms of the temporal peak negative pressure, are found to lie between 1.5 MPa and 3.5 MPa in all six cases. Interpretation of the measured values in terms of the likely threshold at the higher frequencies used in diagnostic ultrasound is considered using a theoretical model.

Acoustics↗
PubMed1995

Colocalization of scavenger receptor in CD68 positive foam cells in verruciform xanthoma.

Verruciform xanthoma is a rare variant of xanthoma that appears predominantly on oral mucosa and the anogenital area. The histologic features are characterized by marked accumulation of foam cells in the papillary dermis with verrucous epidermal acanthosis and hyperkeratosis. However, little is known of the nature or origin of foam cells. Recent studies have emphasized the crucial role of macrophage scavenger receptors in the formation of foam cells in atherogenesis. We examined the immunohistologic localization of scavenger receptors in genital verruciform xanthoma. We found that the massively infiltrated foam cells in the papillary dermis were CD68+ monocyte-macrophage lineage cells, and that the majority of CD68+ cells coexpressed scavenger receptors. The in situ staining pattern of scavenger receptor in foam cells was mainly of an intracytoplasmic vacuolar pattern similar to that of dermal resident macrophages found in normal skin. Furthermore, CD1a+ Langerhans cells, completely negative for scavenger receptor, were markedly decreased in number in verruciform xanthoma. These results indicate that scavenger receptor-bearing CD68+ cells are also actively involved in the development of cutaneous verruciform xanthoma, as has been shown to be the case in atherogenesis.

Aged↗
PubMed1995

Immunochemical characterization of recombinant and native tropomyosins as a new allergen from the house dust mite, Dermatophagoides farinae.

BACKGROUND: Two predominant mite species, Dermatophagoides farinae and Dermatophagoides pteronyssinus, are responsible for the immediate hypersensitivity reaction. Although a large number of antigens and allergens was detected in a whole mite culture extract, only the major allergens of Der I and II groups have been extensively studied. Much information on other important allergens remains to be accumulated. METHODS: A new allergen complementary DNA (cDNA) clone was isolated from a D. farinae protein cDNA library. The expression product of the cDNA and native tropomyosin from D. farinae were purified, characterized, and evaluated. RESULTS: An amino acid sequence deduced from the cDNA clone revealed significant homology with tropomyosins conserved in a wide range of animals. The amino acid sequences of two fragments obtained by degradation of the purified protein with cyanogen bromide coincided completely with the corresponding portions of the deduced amino acid sequence. The native tropomyosin reacted with specific IgE in the 31 sera tested at a high frequency (80.6%), comparable to that of Der f I (90.3%) and Der f II (74.2%). CONCLUSIONS: The cloned cDNA encodes tropomyosin. The high binding response of specific IgE antibodies to recombinant and native tropomyosins demonstrates that mite tropomyosin is an additional important allergen in house dust mite.

Allergens↗
PubMed1995

Evidence for involvement of a 12-residue peptide segment of the heavy chain in the neck region of smooth muscle myosin in formation of the 10S conformation.

Two synthetic peptides having amino acid sequences of the heavy chain segments in the neck region of porcine aorta smooth muscle myosin were used to study the formation of the 10S folded conformation. These peptides, MHC821-835 and MHC835-846, correspond to residues 821-835 and 835-846, respectively, of the chicken gizzard myosin heavy chain. The effects of these peptides on the filament formation of porcine aorta smooth muscle myosin were examined. The filamentous myosin fraction increased on the addition of MHC835-846 at NaCl concentrations lower than 0.25 M for both dephosphorylated and phosphorylated myosin, while the filament formation of dephosphorylated myosin was unaffected by the addition of MHC821-835 up to 30 microM. The filaments formed in the presence of MHC835-846 were observed by electron microscopy to be morphologically indistinguishable from those formed in the absence of the peptide. Rotary shadowed images of dephosphorylated myosin monomers revealed mostly the 10S form in the absence of MHC835-846, while the 6S form was predominant in the presence of the peptide. The results indicate that MHC835-846 inhibits the formation of the 10S conformation. On cosedimentation assaying with myosin, rod and light meromyosin, MHC835-846 bound to each of them with a stoichiometry of nearly 1 mol/mol heavy chain. Altogether, these results suggest that the region in the myosin heavy chain corresponding to MHC835-846 may be involved in the binding site for the light meromyosin portion of myosin for formation of the 10S conformation.

Amino Acid Sequence↗
PubMed1995

Somatic-cell mutations as a possible predictor of cancer risk.

The somatic-mutation theory of carcinogenesis has received strong scientific support from results of recent studies on tumor-suppressor genes. We anticipated that people among the high risk for cancer group, either through exposure to various ionizing radiations or by virtue of unique genotypes, would also manifest increased frequencies of somatic mutation. This report presents the results of two somatic-mutation assays--at the erythrocyte glycophorin A (GPA) and lymphocyte T-cell receptor (TCR) genes--in various groups at high risk for cancer development, including atomic-bomb survivors, patients with various cancers, patients administered Thorotrast, and patients with genetic disorders that make them cancer prone. Although neither the GPA-mutation nor the TCR-mutation assay detects gene mutations directly related to carcinogenesis, increased mutation frequencies were detected by both assays in many individuals among the high-risk groups and among cancer patients. We have continued to follow up those individuals who show values of about three times higher than those of the control group. Thus, these assays may prove useful for identifying high-risk cancer groups and for estimating the effects of mutagens. Such information would constitute a valuable data base for epidemiological studies.

Adult↗
PubMed1995

Enzyme-linked immunosorbent assay of pro-gastrin-releasing peptide for small cell lung cancer patients in comparison with neuron-specific enolase measurement.

Our previous study demonstrated that pro-gastrin-releasing peptide(31-98), or ProGRP, is a specific tumor marker in patients with small cell lung carcinoma (SCLC). Using a newly developed, highly sensitive enzyme-linked immunosorbent assay (ELISA) for ProGRP, we analyzed 1,446 samples including those obtained from 478 lung cancer patients to evaluate the clinical usefulness of this ELISA. Several properties indicated that ProGRP is a useful tumor marker for SCLC. First, ProGRP was specifically elevated in SCLC patients. In non-SCLC patients and patients with non-tumorous lung diseases, its serum level was very rarely elevated. Secondly, ProGRP was a reliable marker, in terms of the marked elevation of serum ProGRP levels in SCLC patients. Thirdly, serum ProGRP levels were elevated in SCLC patients even at a relatively early stage of this disease. Fourthly, changes in the serum ProGRP level showed an excellent correlation with the therapeutic responses in SCLC patients. Neuron-specific enolase (NSE) is accepted as a tumor marker of SCLC patients. With the aim of comparing ProGRP and NSE as tumor markers for SCLC patients, we measured serum NSE levels in all samples collected in the present study. We found that ProGRP was superior to NSE in terms of sensitivity, specificity and reliability. Therefore, we consider that ProGRP can play a major role as a clinical tumor marker for SCLC patients.

Biomarkers, Tumor↗
PubMed1995

Glucosyltransferase from Streptococcus sobrinus Catalyzes Glucosylation of Catechin.

We previously showed that the polymeric forms of polyphenols present in oolong tea extract exhibited strong inhibitory activities against glucosyltransferases (GTases) of mutans streptococci, while green tea extract, which is rich in catechins, did not show such GTase-inhibitory activities. In this study, (+)-catechin [2-(3,4-dihydroxyphenyl)-3,4-dihydro-2H-1-benzopyran-3,5,7-triol] was found to be glucosylated by the GTase of Streptococcus sobrinus 6715 with sucrose as the substrate, and the product was identified as 4(prm1)-O-(alpha)-d-glucopyranosyl-(+)-catechin, with a molecular weight of 452. The (alpha)-glucosylated (+)-catechin did not exhibit significant inhibition of glucan synthesis from sucrose by the GTase, which is in contrast to the polymeric polyphenols isolated from oolong tea leaves.

Journal Article↗
PubMed1995

Lung surfactant protein-A and carcinoembryonic antigen in pleural effusions due to lung adenocarcinoma and malignant mesothelioma.

Lung surfactant protein-A (SP-A) is a major phospholipid-associated glycoprotein in surfactant, and is a useful immunohistochemical marker for lung adenocarcinoma. Carcinoembryonic antigen (CEA) has not been immunohistochemically detected in mesothelioma. In pleural effusions due to malignant mesothelioma, very low concentrations of SP-A and CEA can be expected. We studied the value of combined determinations of CEA and SP-A in pleural fluid to distinguish between lung adenocarcinoma and mesothelioma. SP-A and CEA concentrations were measured in pleural effusions from 78 patients with lung adenocarcinoma and 10 with malignant mesothelioma. SP-A concentrations in pleural effusions due to lung adenocarcinoma and mesothelioma were 516 +/- 140 and 16.9 +/- 3.6 ng.ml-1 (mean +/- SEM), respectively. CEA concentrations in pleural effusions due to lung adenocarcinoma and mesothelioma were 239 +/- 92.4 and 1.7 +/- 0.3 ng.ml-1, respectively. SP-A values did not exceed 100 ng.ml-1 in any of 10 mesotheliomas, whilst in 37 of 78 lung adenocarcinomas they did. CEA values did not exceed 10 ng.ml-1 in any of 10 mesotheliomas, whilst in 53 of 78 lung adenocarcinomas they did. Increased values of SP-A and/or CEA were found in pleural effusions from 67 of 78 lung adenocarcinomas. It is concluded that a combination of CEA and SP-A assays in pleural effusions will be helpful for discriminating lung adenocarcinoma from mesothelioma.

Adenocarcinoma↗
PubMed1995

Purification and characterization of membrane-bound hydrogenase from a thermophilic hydrogen-oxidizing bacterium, Pseudomonas hydrogenothermophila strain TH-1.

A membrane-bound hydrogenase was purified aerobically by one step using a hydroxyapatite column after solubilization by acetone treatment from a thermophilic hydrogen-oxidizing bacterium, Pseudomonas hydrogenothermophila strain TH-1. The enzyme consists of two polypeptides of 63 and 31 kDa, respectively. The amino-terminal amino acid sequences of both subunits were homologous to membrane-bound type [Ni-Fe] hydrogenases from other origins. The thermostability under a hydrogen gas atmosphere is highly stable at 50 degrees C, which is the optimum temperature for the cell growth.

Amino Acid Sequence↗
PubMed1995

Application of monoclonal antibodies to histologic diagnosis of gastric cancers.

Histologic diagnosis of poorly differentiated gastric adenocarcinomas by conventional hematoxylin-eosin (HE) staining is often limited by the quality of gastroendoscopic biopsy specimens. In this study we attempted to identify gastric cancer cells in biopsy specimens and ascites of gastric cancer patients using the gastric cancer reactive monoclonal antibodies S202 and S74. Twenty-four of 25 specimens shown to contain cancer cells by HE staining were stained positively by monoclonal antibody S202. In contrast, 3 of 16 specimens that were diagnosed as not including cancer cells by HE staining was stained positively by S202. The possibility that cancer cells in the biopsy specimens were not detected by HE staining cannot be ruled out. Cancer cells in ascites of patients diagnosed with carcinomatous peritonitis by Papanicolaou staining were stained positively by monoclonal antibody S74. From these results, we conclude that monoclonal antibodies S202 and S74 may be useful supplemental agents for the diagnosis of gastric cancer.

Adenocarcinoma↗
PubMed1995

Collagenous colitis.

Collagenous colitis is characterized clinically by chronic watery diarrhea and pathologically by colonic mucosal subepithelial collagen deposition. We report a 72-year-old woman who had collagenous colitis associated with chronic watery diarrhea. She received a non-steroidal anti-inflammatory agent (sulindac) because of rheumatoid arthritis. Histological examination of biopsy showed a thick subepithelial collagen layer with lymphocytes, plasma cells, and infiltration of a few eosinocytes in the lamina propria. These findings led to the diagnosis of collagenous colitis. After treatment with salazosulfapyridine, her bowel movement became normalized and mucosal subepithelial collagen deposition disappeared.

Aged↗
PubMed1995

Polymyositis associated with thymoma and the subsequent development of pure red cell aplasia.

A 53-year-old woman with polymyositis associated with thymoma subsequently developed pure red cell aplasia (PRCA). She was hospitalized because of fever and muscle weakness, and diagnosed as having polymyositis by muscle biopsy. Remarkable clinical improvement followed administration of prednisolone. Progressive anemia became evident, however, while prednisolone was being tapered. Erythroid aplasia and the presence of thymoma confirmed the diagnosis of PRCA. Further examinations revealed that cytotoxic T cells may play an important role in the pathogenesis of this case.

Cytotoxicity, Immunologic↗
PubMed1995

Expression of cytokine mRNA in gastric mucosa with Helicobacter pylori infection.

BACKGROUND: We have studied the cytokine production patterns in gastric mucosal biopsy specimens with and without the Helicobacter pylori infection, using a reverse transcription-polymerase chain reaction (RT-PCR) method capable of detecting low levels of specific mRNA. METHODS: Total RNA was prepared from biopsy specimens with the acid guanidinium thiocyanate-phenol-chloroform method. cDNA was synthesized by M-MLV RTase and amplified using the oligonucleotide primers specific for interleukin-1 beta (IL-1beta), IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, tumor necrosis factor-alpha (TNF-alpha), interferon-alpha (IFN-alpha), IFN-beta, and IFN-gamma by PCR methods. RESULTS: Although IL-1 beta and IFN-gamma mRNA were detected in most specimens, IL-2, IL-3, IL-4, IL-5, IL-9, TNF-alpha, and IFN-beta mRNA were not detected at all. The expressions of IL-7 and IL-8 mRNA were significantly higher in H. pylori-positive gastritis than in H. pylori-negative normal controls. There was a significant correlation between the expression of IL-8 mRNA and the severity of gastritis both in the antrum and in the corpus. On the other hand, there was a significant correlation between the expression of IL-7 mRNA and the severity of gastritis only in the corpus. CONCLUSIONS: These findings suggest that some cytokines, especially IL-7 and IL-8, play some roles in H. pylori-associated gastritis.

Adult↗
PubMed1995

Immunohistochemical and ultrastructural detection of advanced glycation end products in atherosclerotic lesions of human aorta with a novel specific monoclonal antibody.

To elucidate the deposition of advanced glycation end products (AGEs) in aortic atherosclerosis, aortic walls were obtained from 25 autopsy cases and examined immunohistochemically and immunoelectron microscopically with a monoclonal antibody specific for AGEs, 6D12. Among the autopsy cases, atherosclerotic lesions were found in the aortas of 22 cases and were composed of diffuse intimal thickening, fatty streaks, atherosclerotic plaques, and/or complicated lesions. In these cases, intracellular AGE accumulation was demonstrated in the intimal lesions of aortic atherosclerosis in 12 cases. Compared with the diffuse intimal thickening, intracellular AGE accumulation was marked in the fatty streaks and atherosclerotic plaques. Immunohistochemical double staining with 6D12 and monoclonal antibodies for macrophages or muscle actin or a polyclonal antibody for scavenger receptors demonstrated that the AGE accumulation in macrophages or their related foam cells was marked in the diffuse intimal thickening and fatty streak lesions and that almost all macrophages and macrophage-derived foam cells possessed scavenger receptors. Immunoelectron microscopic observation revealed the localization of 6D12-positive reaction in lysosomal lipid vacuoles or electron-dense granules of the foam cells. These results indicate that AGE accumulation occurs in macrophages, smooth muscle cells, and their related foam cells.

Adult↗