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Biomedical subjects

A Kono

Publications and source records attributed to A Kono.

At least 55 records · Page 3Linked to original sources

A very small juxtaglomerular cell tumor preoperatively identified by magnetic resonance imaging.

We describe a 31-year-old man. Although the plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were elevated, computed tomography and rapid sequence pyelography disclosed no abnormality. However, based on the findings of the small tumor (8 x 8 mm) in the kidney visualized by magnetic resonance imaging (MRI) and excessive PRA in the right renal vein, tumor resection was performed. The positive immunohistochemical staining of renin and the visualization of renin mRNA by in situ hybridization provided evidence supporting the diagnosis of juxtaglomerular cell tumor. Blood pressure, PRA, and PAC were normalized after the surgery. The observations suggest that MRI is a powerful diagnostic procedure in small juxtaglomerular cell tumor.

Adenocarcinoma↗

Gene structure of rat cholecystokinin type-A receptor.

Little is known about the gene structure and mRNA expression of cholecystokinin type-A(CCKA) receptor in animals or in human. By screening an EMBL phage library containing partially digested Long-Evans rat DNA, we isolated 7 genomic clones covering a continuous 27 kb region over which a rat CCKA receptor gene spanned. The gene is approximately 10 kb in length containing the entire coding region of the rat CCKA receptor cDNA and consists of five exons interrupted by four introns. The expected sizes of the transcripts from the initiation sites were consistent with the results of northern blot analyses.

Amino Acid Sequence↗

An animal model of congenital defect of gene expression of cholecystokinin (CCK)-A receptor.

Expressions of the CCK-A and B receptor genes in fetal and adult pancreas of OLETF rats were examined by the reverse transcriptase polymerase chain reaction followed by Southern blot hybridization. The pancreatic responses to various stimulants were examined in vitro and results were compared with those of control (LETO) rats. CCK-A receptor mRNA was not expressed in the fetal pancreas of either strain or in the adult pancreas of OLETF rats, but was expressed in the adult pancreas of LETO rats. CCK-B receptor mRNA was expressed in fetal and adult pancreas in both strains. Southern blot hybridization indicated a difference in gene structure in the two strains. The maximal effective concentrations of neuromedin C, carbachol, and secretin for amylase secretion and intracellular Ca2+ movement stimulated by carbachol and neuromedin C were similar in the two strains. CCK-8 and the non-sulfated form stimulated amylase secretion only in LETO rats. These results suggest that OLETF rats are a new model of a congenital defect of the CCK-A receptor gene and should be useful for determining CCK receptor function.

Amylases↗

Frequent expression of genes for receptor tyrosine kinases and their ligands in human pancreatic cancer cells.

Limited information is available concerning the involvement of growth factor receptors and their ligands in the pathogenesis of human pancreatic cancer. We analyzed 12 human pancreatic cancer cell lines by Northern blot analysis for the expression of 9 receptor tyrosine kinase (RTKs) and 6 growth factors. The effect of a monoclonal antibody (MAb) against transforming growth factor-alpha (TGF-alpha) on in vitro pancreatic cancer cell growth was also assessed, mRNA for EGF-R, c-erbB-2 and c-erbB-3 was expressed in 12 (100%), 12 (100%), and 7 (58%), respectively, of the cell lines examined. In addition, 8 (67%) cell lines expressed the c-met/receptor for hepatocyte growth factor. As for ligands, TGF-alpha mRNA was detected in 10 (83%) cell lines; MAb against TGF-alpha inhibited growth of the 2 cell lines examined. Furthermore, mRNA for amphiregulin (AR) was expressed in 10 (83%) cell lines. Coexpression of TGF-alpha, AR, and EGF-R was observed in 9 (75%) cell lines. These results support the concept that several specified types of RTKs and their ligands are closely involved in regulation of the growth of human pancreatic cancer cells.

ErbB Receptors↗

Cytotoxicity of CPT-11 for gastrointestinal cancer cells cultured on fixed-contact-sensitive plates.

The cytotoxicity of SN-38, the major metabolite of CPT-11 (7-ethyl-10-[4-(1-piperidino)-1- piperidino]carbonyloxycamptothecin, was compared among gastrointestinal carcinomas of every organ, and between primary and metastatic lesions of every organ-originated gastrointestinal carcinoma, by an in vitro anticancer drug sensitivity test using fixed-contact-sensitive plates. The rates of cases having a high response (percent survival 75% or lower) to SN-38 but a low response (percent survival above 75%) to cisplatin, mitomycin C (MMC), adriamycin (ADM) and 5-fluorouracil (5-FU) were 14.6, 19.4, 15.6 and 27.0%, respectively. While, the rates of cases having a high response to cisplatin, MMC, ADM and 5-FU but a low response to SN-38 were 7.3, 2.8, 9.4 and 13.5%, respectively. Each of the former rates were higher than each of the latter rates. In particular, the former rate for MMC was significantly higher than the latter rate (p = 0.04). Two cases with colon cancer showed a high response only to SN-38. The percent survival of primary lesions in colon cancer was significantly lower than that in stomach cancer. The rates of hepatocellular carcinoma cases having a high response to SN-38 but a low response to cisplatin, MMC, ADM and 5-FU were 16.7, 16.7, 0 and 25%, respectively. Only one case had a high response to 5-FU but a low response to SN-38. The percent survival of metastatic lesions in pancreatic cancer was significantly lower than that of primary lesions. From this study, we recommend the further clinical trial of CPT-11 for colon and hepato-cellular cancers.

Animals↗

Effect of a cholecystokinin (CCK) antagonist (CR 1505) on gene expressions of CCK and secretin in rat intestine.

The effects of intragastric administration of cholecystokinin (CCK) antagonist (CR 1505; 60-300 mg/kg/day) to rats for 3 days on the gene expressions of CCK and secretin, the plasma CCK immunoreactivity, and the CCK content in the intestinal mucosa were examined. CR 1505 increased the level of CCK mRNA in the intestine dose dependently to up to 1.6 times the level in control rats but did not affect the level of secretin mRNA. It also significantly increased the plasma CCK immunoreactivity and the amount of CCK extracted from intestine with acid dose dependently. CR 1505 tended to decrease the trypsin activity in the intestine. These results suggest that ingested CR 1505 increased the CCK mRNA level in the intestine.

Animals↗

Therapy and imaging of pancreatic carcinoma xenografts with radioiodine-labeled chimeric monoclonal antibody A10 and its Fab fragment.

Recombinant mouse/human chimeric monoclonal antibody A10 (ch-A10) and its Fab fragment (ch-Fab) react with carcinoembryonic antigen on various gastrointestinal carcinomas. We performed biodistribution studies with 125I-labeled ch-A10 and ch-Fab in an antigen-positive human pancreatic carcinoma (BxPC-3) xenograft model. We also evaluated the anti-tumor effect of 131I-labeled ch-A10, and studied the detection of BxPC-3 xenografts with 123I-labeled ch-Fab in whole body scintigraphy. In comparative biodistribution studies, the tumor uptake of 125I-labeled ch-A10 was significantly greater than that of 125I-labeled ch-Fab 24 h post-injection. However, the tumor-to-blood ratio was 46.8 for ch-Fab at 24 h post-injection, while it was only 1.4 for ch-A10. Microautoradiography studies showed that ch-Fab penetrated more uniformly into the tumor nodules than did ch-A10. In mice given a therapeutic dose of 131I-labeled ch-A10, a significant inhibition of tumor growth was seen, while control 131-I-labeled human IgG did not affect tumor growth. Leukocyte toxicity was observed within 3 weeks after injection of 131I-labeled ch-A10, but leukocyte counts recovered to normal levels at 8 weeks post-injection. In whole-body scintigraphy, clear and rapid tumor imaging was obtained with 200 microCi of 123I-labeled ch-Fab 24 h post-injection. These results suggest that radioiodine-labeled chimeric A10 antibodies could potentially be useful candidates for radioimmunotherapy and radioimmunodetection of pancreatic carcinomas.

Adult↗

Characteristics of aldosterone-producing adenoma responsive to upright posture.

A small subgroup of primary aldosteronism due to aldosteronoma, named aldosterone-producing renin-responsive adenoma (AP-RA), has been reported to masquerade as idiopathic hyperaldosteronism (IHA) because of the responsiveness of the plasma aldosterone concentration (PAC) to upright posture (UP). We found two patients with AP-RA in 19 patients with aldosteronoma who were examined by UP stimulation and were treated surgically. In 17 patients with typical aldosterone-producing adenoma (APA), PAC decreased or increased only slightly (less than 200% of the basal level); in contrast, it increased to over 300% of the basal level in two patients with AP-RA. The two groups were comparatively studied as to their hormonal levels, adrenal computed tomography (CT) scan and histological findings in order to clarify the characteristics of AP-RA. Basal PAC was within the normal range (11.1 and 13.0 ng/dl) in AP-RA but in APA it ranged from 14.8 to 58.1 ng/dl with a mean of 32.3 +/- 2.7 ng/dl. The diameters of the adenoma in AP-RA were apparently smaller (6 and 9 mm) than those in APA ranged from 10 to 25 mm with a mean of 15.5 +/- 1.1 mm. After a contrast medium was injected at CT scan, the density of the normal adrenal gland adjacent to the adenoma increased but that of the adenoma did not in APA, making a clear distinction between the adenoma and the gland. On the other hand, the density of the adenoma and gland increased to almost the same degree in AP-RA.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Cortex Neoplasms↗

Lack of satiety effect of cholecystokinin (CCK) in a new rat model not expressing the CCK-A receptor gene.

This work expands recent observations that Otsuka Long-Evans Tokushima Fatty (OLETF) rats show little or no pancreatic expression of the cholecystokinin (CCK)-A receptor gene. We examined whether the CCK-A and -B receptor genes were expressed in the brain (hypothalamus) of OLETF rats in comparison with control (Long-Evans Tokushima Otsuka = LETO) rats. CCK-A receptor mRNA was detected in the hypothalamus of LETO rats but not OLETF rats. The CCK-B receptor gene was expressed in the hypothalamus in both strains. Cerebroventricular administration of CCK-8 sulfate inhibited daily food intake in LETO rats, but not in OLETF rats. These results show that in OLETF rats the absence of CCK-A receptor gene expression in the hypothalamus results in hyperphagia because of lack of satiety.

Animals↗

Production and secretion of chromogranin A and pancreastatin by the human pancreatic carcinoma cell line QGP-1N on stimulation with carbachol.

Chromogranin A (CGA) is thought to be a precursor of pancreastatin (PST). Carbachol (Cch) stimulated the secretion of CGA and PST from QGP-1N cells derived from a human pancreatic islet cell tumor. Atropine inhibited the secretion of both. Sodium fluoride, phorbol ester, and calcium ionophore also stimulated the secretion of both. Cch (10(-5) M) stimulated inositol 1,4,5-trisphosphate production in QGP-1N cells. Stimulation with Cch increased the total amount of PST in the cells and the medium 1.7-fold and decreased the amount of CGA in the cells and medium. QGP-1N cells were labelled with [35S]methionine, and then CGA and PST in the cells and medium were immunoprecipitated with specific antisera, and separated by electrophoresis in polyacrylamide gel. Stimulation with Cch resulted in an increase in the intensity of PST-immunoreactive bands and a decrease in those of CGA-immunoreactive bands. Cch did not increase the cellular level of CGA messenger RNA. These results suggested that (1) the secretion of CGA and PST from QGP-1N cells is regulated mainly through muscarinic receptors coupled with activation of polyphosphoinositide breakdown by a G protein, with intracellular calcium ion and protein kinase C playing a role in the stimulus-secretion coupling and that (2) Cch may induce the secretion of PST and CGA and processing from CGA to PST.

Carcinoma, Islet Cell↗

Little or no expression of the cholecystokinin-A receptor gene in the pancreas of diabetic rats (Otsuka Long-Evans Tokushima Fatty = OLETF rats).

Expression of the CCK-A receptor gene in the pancreas and pancreatic exocrine function was examined in diabetic model rats (OLETF) at 5 wks of age. Little or no CCK-A receptor was detected in the pancreas of OLETF rats. Pancreatic exocrine function in response to exogenous CCK and to bile-pancreatic juice diversion (endogenous CCK) was impaired in conscious OLETF rats. The pancreatic insulin and protein contents of OLETF (Otsuka Long-Evans Tokushima Fatty) and control LETO (Long-Evans Tokushima Otsuka) rats were not significantly different. No histological abnormalities or expression of pancreatitis associated protein (PAP) mRNA was detected in the pancreas in either group. These results suggest that OLETF rats are a new experimental model for congenital deficiency of CCK-A receptor in the pancreas.

Animals↗

Expression of the cholecystokinin precursor gene in rat tissues.

Cholecystokinin, a brain gut peptide that stimulates gall bladder contraction and pancreatic exocrine secretion, also acts as a neurotransmitter. In this study, we demonstrated that small amounts of cholecystokinin precursor mRNA were expressed in the heart, lung, and kidney, as well as in the brain and the small intestine. The nucleotide sequences of the coding regions of the cholecystokinin precursor mRNA in these tissues were identical to those of the small intestine, indicating that cholecystokinin precursor proteins produced in these tissues are identical to those in small intestine. This is the first report demonstrating that the cholecystokinin precursor gene is expressed in the heart, lung, and kidney, as well as in the gastrointestinal tract and brain.

Animals↗

Pancreastatin molecular forms in normal human plasma.

Circulating molecular forms with pancreastatin (PST)-like immunoreactivity in plasma from normal subjects were examined. An immunoreactive form corresponding to a human PST-like sequence [human chromogranin-A-(250-301)] (hPST-52) and a larger form (mol wt 15-21 kDa) were detected by gel filtration of plasma from normal subjects. On high performance liquid chromatography, predominant immunoreactive forms coeluted with the three larger forms which were purified from the xenograft of human pancreatic islet cell carcinoma cell line QGP-1N cells and with synthetic hPST-52. The fraction containing larger forms purified from xenograft of QGP-1N cells had biological activity equivalent to that of hPST-52 on the inhibition of pancreatic exocrine secretion. These results suggest that the larger molecular forms as well as hPST-52 may be physiologically important circulating forms of PST in human.

Animals↗

Production of endothelin-1 and thrombomodulin by human pancreatic cancer cells.

Analysis of bioactive substances produced by cancer cells is one approach to understanding the biological features of human cancer. One of these bioactive substances is endothelin (ET)-1, a peptide with potent vasoconstrictive activity produced by vascular endothelial cells. We have previously reported the production of ET-1 by several types of human cancer, especially pancreatic cancer cells. To elucidate whether these cancer cells might share biological characteristics with vascular endothelial cells, we investigated the production of three ET isoforms in pancreatic cancer cells, using a specific radioimmunoassay. Further, we also investigated whether these cells produce thrombomodulin (TM), another product of endothelial cells functioning as a modulator of procoagulant activity. ET-1 was detected in 11 of 12 pancreatic cancer cell lines (92%) while ET-2 and ET-3 were detectable in only one cell line. Gel filtration analysis confirmed the presence of ET-1. Moreover, TM was detected in the cell lysates of 11 of the 12 cell lines (92%) and it was released into the culture medium in the majority (58%) of these cell lines. TM mRNA was also detected in these cells. In addition, TM was demonstrated immunocytochemically along the cell surface. These results suggest that pancreatic cancer cells share two characteristics with endothelial cells: the production of ET-1 and TM.

Antibodies, Monoclonal↗

[Establishment of a human colon cancer-derived cell line (KC-1) which produces CEA, CA 19-9 and sialyl SSEA-1(SLX)].

A human colon cancer-derived cell line, KC-1, was established from the surgical specimen of mucinous adenocarcinoma of the colon. The cells grew as monolayers, showing formation of irregular aggregation of cells and pleomorphic nuclei. The doubling time in vitro was 56.6 hours. The cells produced CEA, CA19-9 and sialyl SSEA-1(SLX). Chromosome numbers were distributed between 79 and 83 with many structural abnormalities. A point mutation of the Ki-ras gene in codon 61 (CAA-->CAT) was found. The cells have been subcultured 13 times during these three years. This cell line can be useful for investigations of colon cancer.

Adenocarcinoma, Mucinous↗

[A 46-year-old man with cardiac failure and statues epileptics].

We report a 46-year-old man with bacterial endocarditis and cardiac failure, who developed status epileptics. The patient was apparently well until July of 1991 when there was a gradual onset of fever and general fatigue. He was hospitalized to the cardiology service of our hospital where diagnosis of bacterial endocarditis and aortic insufficiency was made. On October 9, 1991, he suddenly developed cardiogenic shock, and emergency replacement of the aortic valve was made; at the operation, the main trunk of the left coronary artery showed embolic occlusion, and the myocardial movement was markedly diminished; serum creatine kinase was 3.150 IU/l. His cardiac failure did not resolve, and renal failure developed in December 1991, for which peritoneal dialysis was necessary. On February 2, 1992, he suddenly developed a clonic seizure which started from his face with a transient post-ictal left hemiparesis; a cranial CT scan was unremarkable. He was treated with phenytoin and glycerol, however, he developed status epileptics on February 3; he developed cardiac arrest after the injection of phenytoin 750 mg. He was resuscitated, however, his status did not resolve. Neurological consultation was asked on February 4. On physical examination, his blood pressure was 80/40 mmHg heart rate 77/min and regular, and body temperature 39.1 degrees C. The palpebral conjunctiva were slightly anemic, however, the bulbar conjunctiva were not icteric. No cervical adenopathy was noted. Glade II systolic murmur was heard in the apex; the lungs were clear. The abdomen was flat and soft without organomegaly. No edema was present in the legs. On neurologic examination, he was comatose without response to painful stimuli. He repeatedly had convulsion lasting for 30 seconds every 2 to 3 minutes; his convulsions started with the conjugate deviation of the eyes to the left followed by turning of the head toward left, and then clonic convulsions started in this left upper limb extending to other extremities. The optic fundi were unable to visualize because of corneal clouding; light reflex was sluggish on the right side; no oculocephalic response was elicited; corneal reflex was also lost bilaterally. Extremities were hypotonic, and no automatic movement was seen. The triceps brachii reflex was diminished, but all the other deep reflexes were lost; no plantar response was elicited. Meningeal sign was absent. He was treated with intravenous diazepam; the interval of convulsions prolonged, however, blood pressure dropped to 40 to 40 mmHg. On February 4, intravenous thiopental anesthesia was instituted, and assisted respiration was started.(ABSTRACT TRUNCATED AT 400 WORDS)

Brain↗