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Biomedical subjects

K Isobe

Publications and source records attributed to K Isobe.

At least 199 records · Page 11Linked to original sources
PubMed1994

[Early detection of primary liver cancer--diagnosis of small liver cancer by needle aspiration biopsy].

Small liver cancer is defined as a solitary hepatocellular carcinoma (HCC) with a diameter less than 2cm. To detect liver cancer as early as possible, patients with liver cirrhosis are screened by ultrasound scanning. Pathological diagnosis in needle aspiration biopsy materials is needed because of low positivity of imaging other than ultrasound scanning. Pathological features are different from those of classical hepatocellular carcinoma. Most of the small HCCs are characterized by the following features: (1) increased cellularity, (2) increased nucleus/cytoplasm ratio, (3) irregular thin trabecular pattern, (4) pseudoglandular or acinar structures, (5) increased staining affinity (eosinophilic/basophilic), (6) frequent fatty change, and (7) residue of the portal tract. Capsules of HCCs, 1-1.5 cm in diameter, are formed. Before the formation of capsules, cancerous cells show a replacing growth pattern. Two cases of small HCC are presented, and these characteristic features are explained.

Biopsy, Needle↗
PubMed1993

The effects of nitric oxide on chondrocytes and lymphocytes.

ConcanavalinA (ConA)-activated lymphocytes markedly induced the production of nitric oxide from chondrocytes. The nitric oxide significantly inhibited the proliferation of both the chondrocytes themselves and the lymphocytes. When culture supernatant from ConA-activated lymphocytes was added to culture of chondrocytes, a large amount of nitric oxide was produced. NG-monomethyl-L-arginine (MMA) significantly eliminated both the production of nitric oxide and the inhibition of chondrocyte and lymphocyte proliferation. Furthermore, when MMA was added to the mixed culture of chondrocytes and lymphocytes with ConA, their proliferation was markedly enhanced compared with individual summation. These results indicate that chondrocytes produce not only nitric oxide but also a lymphocyte stimulating factor, the effects of which are, however, usually masked by the nitric oxide.

Animals↗
PubMed1993

Survival of syngeneic and allogeneic grafted bone in transgenic mice.

The viability of syngeneic, allogeneic and xenogeneic bone grafts was investigated in mice and rats by the polymerase chain reaction method using carcinoembryonic antigen transgenic mice as donors. DNA of syngeneic grafts was detected more than 24 weeks after bone grafting. In contrast, the DNA of allogeneic thymic grafts and xenogeneic bone grafts disappeared by 3 weeks after transplantation. However, DNA of allogeneic bone grafts was detected until 20 weeks after transplantation. Histological examination at 12 weeks after surgery detected some donor nuclei in both syngeneic and allogeneic bone grafts.

Animals↗
PubMed1993

Higher expression of topoisomerase II in lung cancers than normal lung tissues: different expression pattern from topoisomerase I.

To examine the expression of topoisomerase I and topoisomerase II in primary lung cancer specimens at mRNA level, we carried out Northern blot analysis. As for topoisomerase I expression, there was no remarkable difference between lung cancer specimens and non-cancerous lung tissues. On the other hand, we could detect topoisomerase II mRNA in almost all lung cancer specimens, but not in non-cancerous tissues. By Southern blot analysis, we could not detect large deletion nor rearrangement in DNA level. These results suggest that the expression of topoisomerase II is highly increased in lung cancer at mRNA level and drugs against topoisomerase II might be more tumor-specific than those against topoisomerase I.

Adenocarcinoma↗
PubMed1993

Abundant production of nitric oxide from murine macrophages by direct stimulation of tumor cells.

By the coculture of tumor cells and resident murine peritoneal macrophages, we found that P1HTR tumor cells, which were the subline of P815 mastocytoma, stimulated syngeneic or allogeneic peritoneal macrophages to produce nitric oxide. This nitric oxide in turn kills P1HTR target cells. The cytotoxicity and nitric oxide production were completely abolished by the addition of L-arginine homologue NG-monomethyl-L-arginine. The original P815 tumor cells had only weak activity to stimulate macrophages to produce nitric oxide and were weekly killed by coculture of P815 and resident macrophages. Macrophage cell line, RAW264-7, was also stimulated to produce nitric oxide by P1HTR cells. The ability to stimulate macrophages to produce nitric oxide resided on the membranous fragment of P1HTR cells.

Animals↗
PubMed1993

Primary structure determination of mono- and diacylglycerol lipase from Penicillium camembertii.

The complete amino acid sequence of mono- and diacylglycerol lipase from Penicillium camembertii was determined. This lipase has a single polypeptide chain consisting of 276 amino acid residues with two disulfide linkages. The primary structure was revealed by sequencing the digests of the intact and S-pyridylethylated proteins by trypsin, endoproteinase Lys-C and V8 protease. The two-dimensional electrophoresis was also carried out to confirm the internal sequence. The catalytic triad of this lipase was Ser, Asp and His, and one potential N-glycosylation site was also revealed.

Amino Acid Sequence↗
PubMed1993

[Extracellular ATP evoked catecholamine release and inositol phosphates formation in cultured porcine adrenal medullary cells].

ATP is ubiquitously present in neural tissues and is released during nerve stimulation. It is known that splanchnic nerve terminals located in adrenal medulla also contain acetylcholine and ATP. These substances may be released concomitantly with nerve stimulation. ATP can exert its effects on neuron-effector junctions by acting directly as a neurotransmitter by increasing or decreasing the release of other neurotransmitters or by modulating their actions. Chern et al. reported that ATP and adenosine inhibited acetylcholine stimulated secretion of catecholamine from isolated bovine adrenal medullary cells. However, Kim et al. showed that extracellular ATP stimulated catecholamine secretion from cultured bovine adrenal medullary cells. Therefore, we investigated the effect of ATP on second messengers levels in cultured porcine adrenal medullary cells as well as catecholamine release from the cells. ATP (500 microM-5mM) evoked catecholamine release significantly (p < 0.05). An unhydrolyzable ATP analogue, ATP gamma S, was several times more potent than ATP in the secretion. ATP-evoked maximal secretion of catecholamine was several times less potent than that evoked by carbachol. Removal of extracellular Ca2+ did not effectively inhibit ATP-induced secretion. 45Ca2+ influx was not observed by the addition of ATP. These results indicated that the catecholamine secretion induced by ATP was independent of extracellular Ca2+. ATP evoked cAMP production slightly at 1mM and did not affect cGMP content. On the other hand, ATP (100 microM-5mM) induced a remarkable increase in inositol trisphosphate, a messenger for mobilization of Ca2+ from intracellular storage sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1993

Redox-linked ligand-independent cell surface triggering for extensive protein tyrosine phosphorylation.

Exposure of lymphocytes to 0.2-2 mM HgCl2, a thiol-reactive heavy metal, induced extensive tyrosine phosphorylation of multiple cellular proteins. The phosphorylation started as quickly as 5 s after exposure to HgCl2, and was irreversible. Another 3 thiol-reactive chemicals also displayed similar, though less marked, actions, whereas dithiothreitol, a reducing agent, antagonized the HgCl2 action. The demonstrated new action of HgCl2 indispensably required membrane-intact cells as a target. Whereas exposure of lymphocytes to > 0.2 mM HgCl2 caused rapid cell death, 0.01-0.1 mM HgCl2 affected the cells so as to accelerate their c-fos transcription. These results suggest a novel redox-linked mechanism of cell surface triggering of intracellular protein kinase activity, which is independent of receptor-ligand interactions.

4-Chloromercuribenzenesulfonate↗
PubMed1993

Nitric oxide production from a macrophage cell line: interaction with autologous and allogeneic lymphocytes.

The indirect stimulation of macrophages to produce nitrite was examined by using the macrophage cell line J774.J774 spontaneously produced nitrite, when cultured at high concentration. J774 cultured in low concentration (< 10(4) cells in 100 microliters) barely produced nitrite. J774 cultured in low concentration produced a large amount of nitrite by the co-culture of nonadherent spleen cells or nonadherent peritoneal exudate cells, which were stimulated with con A, anti-CD3, or staphylococcal enterotoxin A. J774 (BALB/c derived: H-2d) cultured with either syngeneic (BALB/c) or allogeneic (B6; H-2b B10BR; H-2k) nonadherent lymphocytes, which were stimulated with conA or anti-CD3, produced nitric oxide. However, J774 produced nitric oxide by stimulation with SEA only when co-cultured with SEA-reactive T lymphocytes. Peritoneal exudate cells from mice, which did not proliferate by the stimulation of conA or anti-CD3, proliferated well by the addition of L-arginine homologue, NG-monomethyl-L-arginine. The proliferation of nonadherent peritoneal exudate cells stimulated with conA or anti-CD3 was suppressed by the addition of peritoneal macrophages. This suppression was abolished by the addition of NG-monomethyl-L-arginine.

Animals↗
PubMed1993

Matrix-assisted ultraviolet laser desorption/ionization mass spectrometry applied to multiple forms of lipases.

Matrix-assisted ultraviolet laser desorption/ionization mass spectrometry was used to investigate heterogeneous patterns and molecular masses of microbial lipases from Penicillium camembertii, Geotrichum candidum, and Pseudomonas sp. Mass spectral peaks of the native, glycosylated lipases from P. camembertii and G. candidum were broader than those of the corresponding deglycosylated enzymes, indicative of heterogeneous glycosylations. The broader peaks in the mass spectra were caused by an overlapping of unresolved peaks, derived from single glycoprotein species. Molecular masses determined for the deglycosylated proteins were in excellent agreement with those deduced from amino acid composition and sequence data, whereas with conventional biochemical methods (gelfiltration, sodium dodecyl sulfate-polyacrylamide gel electrophoresis) only very rough estimations of molecular masses were possible. By mass spectrometric analysis of the four fractions of chromatographically separated P. camembertii lipase molecular masses of 29,990, 34,030, 31,990, and 32,140 Da were found before and 29,960, 29,980, 29,990 and 30,010 Da, respectively, after deglycosylation. Thus from the four native fractions of P. camembertii lipase three were glycoproteins. G. candidum lipase showed an average molecular mass of 63,500 Da for the heterogeneously deglycosylated native form and a molecular mass of 59,650 Da for the deglycosylated enzyme. For the Pseudomonas lipase, which could only be isolated with lipids firmly attached, a molecular mass of 32,890 Da was determined, in close agreement with that derived from the cDNA sequence.

Bacterial Proteins↗
PubMed1993

Expression of carcinoembryonic antigen (CEA) and nonspecific crossreacting antigen (NCA) in gastrointestinal cancer; the correlation with degree of differentiation.

In spite of its reputation as a tumour marker, little is known about the function of carcinoembryonic antigen (CEA). We examined the mRNA expression of CEA and NCA in 26 gastric and 14 colorectal cancers together with adjacent morphologically normal mucosae. There was no significant difference between the CEA mRNA levels of colorectal cancer and adjacent mucosa, whereas the CEA mRNA levels were significantly elevated in gastric cancer compared with normal gastric mucosa. The expression of NCA, on the other hand, was more cancer-specific and was significantly up-regulated in both gastric and colorectal cancers compared with the corresponding normal mucosae. No correlation was found between the mRNA level and plasma CEA value. No significant up-regulation was recognised in the node positive cancer, cancer with distant metastasis, or the metastatic tissues themselves. Marked diversity in the degree of differentiation in gastric cancer tissues, however, resulted in varied expression of the CEA gene family, compared with the constantly high expression found in colorectal cancer. Further analysis revealed significant up-regulation of NCA in well and moderately differentiated gastric cancers over poorly differentiated cancers, suggesting that NCA might have roles in differentiation.

Antigens, Neoplasm↗
PubMed1993

Nonspecific crossreacting antigen (NCA) is a major member of the carcinoembryonic antigen (CEA)-related gene family expressed in lung cancer.

Carcinoembryonic antigen (CEA) is one of the most important tumour markers in the management of human carcinoma, including lung cancer. So far, however, because of the nonspecificity of anti-CEA antibodies, it remains unclear whether the experimental measurements of CEA expression really reflect genuine CEA. In normal lung, nonspecific cross reacting antigen (NCA) has been described as a major component of CEA-related antigens. Recently isolated CEA and NCA cDNA clones enabled us to analyse CEA and NCA expression of in vivo tumour specimens and tumour cell lines at mRNA levels. NCA-specific mRNA (but not CEA-specific mRNA) was detected in all normal lung tissues examined. Of 21 lung cancer tissue specimens, nine expressed both NCA and CEA and five expressed only NCA. Of 16 tumour cell lines, two expressed only NCA and one expressed both NCA and CEA, although its level of CEA mRNA was weaker than that of NCA mRNA. Therefore, CEA-related mRNA expression was always accompanied by NCA mRNA expression; there were no cases of CEA mRNA expression alone. These findings suggest that NCA is a major member of the CEA-related gene family expressed in lung cancer.

Animals↗
PubMed1993

Ca(2+)-dependent stimulatory effect of pituitary adenylate cyclase-activating polypeptide on catecholamine secretion from cultured porcine adrenal medullary chromaffin cells.

Pituitary adenylate cyclase-activating polypeptide (PACAP) stimulates catecholamine secretion from cultured porcine adrenal medullary chromaffin cells in a dose-dependent manner with the half-maximal and maximal doses of 30 nM and 1 microM, respectively. Either removal of extracellular Ca2+ or addition of Gd3+, an inorganic Ca2+ channel blocker, very potently inhibits PACAP-induced catecholamine secretion. Both nicardipine (1 microM) and methoxyverapamil (1 microM), blockers of voltage-dependent Ca2+ channels, are also effective in inhibiting PACAP-induced catecholamine secretion. When the intracellular free Ca2+ concentration ([Ca2+]i) is measured in a fura 2-loaded single chromaffin cell, PACAP is found to cause a sustained increase in [Ca2+]i by mobilizing Ca2+ from both extra- and intracellular pools. It is also found that PACAP stimulates the production of inositol phosphates in a dose-dependent manner, which is not abolished by removal of extracellular Ca2+ unlike the case of nicotine. PACAP increases cAMP content in chromaffin cells in a dose-dependent manner. Removal of extracellular Ca2+ enhances PACAP-induced cAMP production but strongly inhibits PACAP-induced catecholamine secretion. Pretreatment of cells with adenosine-3':5'-monophosphothioate, cyclic, Rp-isomer, a cAMP antagonist, does not block PACAP-induced catecholamine secretion. The addition of forskolin or 3-isobutyl-1-methylxanthine does not enhance the PACAP-induced catecholamine secretion. These results indicate that PACAP activates voltage-dependent Ca2+ channels and phospholipase C as well as adenylate cyclase in cultured porcine adrenal medullary cells and strongly suggest that PACAP-induced catecholamine secretion is mainly mediated by activation of voltage-dependent Ca2+ channels.

Adrenal Medulla↗
PubMed1993

Types of traumatic brain injury and regional cerebral blood flow assessed by 99mTc-HMPAO SPECT.

To investigate the relationship between focal and diffuse traumatic brain injury (TBI) and regional cerebral blood flow (rCBF), rCBF changes in the first 24 hours post-trauma were studied in 12 severe head trauma patients using single photon emission computed tomography (SPECT) with 99mtechnetium-hexamethyl propyleneamine oxime. Patients were classified as focal or diffuse TBI based on x-ray computed tomographic (X-CT) findings and neurological signs. In six patients with focal damage, SPECT demonstrated 1) perfusion defect (focal severe ischemia) in the brain region larger than the brain contusion by X-CT, 2) hypoperfusion (focal CBF reduction) in the brain region without abnormality by X-CT, and 3) localized hyperperfusion (focal CBF increase) in the surgically decompressed brain after decompressive craniectomy. Focal damage may be associated with a heterogeneous CBF change by causing various focal CBF derangements. In six patients with diffuse damage, SPECT revealed hypoperfusion in only one patient. Diffuse damage may be associated with a homogeneous CBF change by rarely causing focal CBF derangements. The type of TBI, focal or diffuse, determines the type of CBF change, heterogeneous or homogeneous, in the acute severe head trauma patient.

Adolescent↗
PubMed1993

[Transgenic mice: the basic methods].

This paper introduces the techniques of transgenic mice. The great advances of molecular biology have started to elucidate the mechanism of higher function of the human brain. The introduction of cloned gene to mouse will enable study of the human brain in vivo.

Animals↗
PubMed1993

[Serological diagnosis of adenovirus conjunctivitis].

We compared the serum antibody titers against adenoviruses of pair sera and the identification of isolated adenovirus from 17 patients with acute conjunctivitis. Isolated adenoviruses were Ad3 in ten cases, Ad8 in four cases, Ad37 in two cases, and Ad4 in one case. Among these cases, eleven cases showed identical results in a neutralization test. In one patient from whom Ad3 was isolated, no neutralizing antibody was found. In 3 patients from whom Ad8 or Ad37 was isolated, there were discrepancies between serological results of the neutralization test or the haemagglutination inhibition test, and viral isolation. Antibody titers against adenoviruses subgenus D, such as Ad8, 19 and 37 were increased not only for the isolated serotypes, but also for other serotypes of this subgenous.

Adenovirus Infections, Human↗