Biomedical subjects
K Okubo
Publications and source records attributed to K Okubo.
[The body map: an expression database of human genome].
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A cDNA cloning of human AEBP1 from primary cultured osteoblasts and its expression in a differentiating osteoblastic cell line.
By comparing lists of 3'-directed partial cDNA sequences (gene signatures) randomly collected from various tissues, genes uniquely expressed in individual tissue can be identified. A full length cDNA clone, corresponding to one such gene signature, unique to human osteoblast and adipose tissue, was isolated. This cDNA clone encodes a 845-amino acid protein that is almost identical to the mouse adipocyte transcription factor AEBP1 except that it has additional 105 amino acids in the N terminus. A northern hybridization showed that in the differentiating murine osteoblastic cell line, AEBP1 is also expressed but that it is shut off in the final calcification phase, suggesting a transcriptional repressive effect on genes for bone formation.
Identification and cloning of neuroblastoma-specific and nerve tissue-specific genes through compiled expression profiles.
An expression profile of active genes in a human neuroblastoma cell line CHP134 was obtained by collecting 1222 partial sequences from a 3'-directed cDNA library representing a non-biased mRNA population. By comparing this expression profile with the compiled profiles of multiple tissues, several novel gene transcripts that appeared only in the profile of the neuroblastoma cell line were identified. Further analyses by Northern blotting revealed two specific cDNA clones that are expressed in most of the human neuroblastomas examined, and three that are in some of the human neuroblastoma cell lines as well as in the adult human brain. Full-size cDNAs were cloned using these five partial cDNA sequences as probes and sequenced. A database search revealed that they are all novel and unique sequences: one sharing some amino acid sequence similarities with a cytoskeletal protein, two clones likely to be transcriptional factors, a clone that has characteristic potassium channel properties, and a clone that is non-homologous to any one of the known proteins. Thus, we argue that the collection of 3'-directed cDNA sequences in combination with the compiled expression profiles of active genes in multiple tissues is a powerful tool for discovering novel genes that are specifically expressed in a given cell or tissue, in this case neuroblastomas and/or nerve tissue.
Expression profiles of active genes in human and mouse livers.
An expression profile of active genes in the human liver was obtained by collecting sequences with a 3'-directed cDNA library that faithfully represents composition of the mRNA population. The results show the relative activity of ca. 600 genes in maintaining the hepatocytes and sustaining their liver-specific phenotypes. The most active group of genes are those for the production of plasma proteins, followed by the genes for the synthesis of lipoproteins, protease inhibitors, coagulation factors, and complements. This balance of gene activity was maintained for four independently obtained expression profiles from human livers, including those of adult and fetus. The expression profiling was extended to the liver of adult mouse, used as a model for the molecular etiology of hepatocytes and for examining the effects of drugs. Subtle biological differences between the human and mouse livers are reflected in the global expression profiles of active genes, especially with regard to the synthesis of plasma proteins, lipoproteins and complements. This comparative analysis using expression profiling should find a wide application in comparative biology.
Optical properties of superconducting Bi2Sr2CaCu2O8.
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cDNA cloning and expression of a novel adipose specific collagen-like factor, apM1 (AdiPose Most abundant Gene transcript 1).
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An expression profile of active genes in cultured human keratinocytes.
An expression profile of genes active in cultured human keratinocytes was obtained by collecting 770 partial sequences from a 3'-directed cDNA library that faithfully represents the mRNA population in the source cells. Ninety-four species composed of 258 clones occurred recurrently, and 512 clones appeared only once. The gene which showed the most abundant expression codes for type I keratin 14, the major keratin that is known to be strongly expressed in the basal layer of the epidermis. Altogether 242 gene species were identified in GenBank, 9.5% of which encode cytoskeletal proteins and 14.5% the components of protein synthesis. Keratin synthesis, the unique property of the keratinocyte, has been measured by elevating the level of transcription of several keratin genes. However, there was no expression of the differentiation markers, type II keratin 1 (K1) or type I keratin 10 (K10), indicating that the cells used for our cDNA library construction were in the pre-differentiation stage. By comparing this expression profile with seven expression profiles from other tissues/cells, four clones, including a novel clone were tentatively identified as specific to keratinocytes.
Isolation and chromosomal localization of the human cone cGMP phosphodiesterase gamma cDNA (PDE6H).
By comparing lists of 3'-directed partial cDNA sequences (gene signatures) randomly collected from various tissues, genes unique to each tissue can be identified. A full-size cDNA clone, corresponding to one such tissue-specific gene signature that recurred only in a retina library, was isolated and analyzed. This clone encoded 83 amino acids highly homologous to the bovine blue cone cGMP phosphodiesterase gamma subunit. The retina-specific expression of this gene was confirmed by multiple tissue Northern blotting, and its cone specificity was confirmed by in situ hybridization to a human retina specimen. From these results, we concluded that this clone (HGMW-approved symbol PDE6H) encodes for the gamma subunit of human cone-specific cGMP phosphodiesterase, and it was assigned to chromosome 12p13 by fluorescence in situ hybridization.
Oxygen-radical-scavenging activity of DDMP-conjugated saponins and physiological role in leguminous plant.
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Chemiluminescence of oxygen radical scavengers such as DDMP saponins in the presence of radicals and aldehyde.
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Effects of pancreatic duct ligation and aging on acute taurocholate-induced pancreatitis. Experiments in the perfused pancreas in rats.
CONCLUSION: When taurocholate was injected into the common bile duct, high ductal pressure due to ligation of the pancreatic duct did not produce more damage in the pancreas of both old rats and young adult rats, and levels of pancreatic enzymes in portal venous effluent were lower in old rats than in younger rats. BACKGROUND: The effects of ligation of the pancreatic duct and aging on acute pancreatitis caused by taurocholate are still unclear. METHODS: Young adult and old male Wistar rats were used. Six hours after ligation of the common bile duct in both the duodenum and liver hilus, rats were killed and the pancreata were perfused. Taurocholate or normal saline was injected retrogradely into the common bile duct. The levels of amylase and lipase in the portal venous effluent were determined as markers of damage to the pancreas. The pancreas was also histologically examined after the perfusion experiments using an Image Analysis System. RESULTS: (1) A nonsignificant elevation of pancreatic enzymes was found in portal venous effluent by the retrograde injection of saline into the common bile duct. Injection of taurocholate caused a marked elevation of enzymes in the effluent for the first 30 min after injection, which then gradually decreased. (2) Basal levels of pancreatic enzymes were significantly higher in the ligation group than in the nonligation group. Injection of saline into the common bile duct had no apparent effect on enzymes in the effluent. In contrast, taurocholate injection into the common bile duct produced a marked increase in enzymes in the portal venous effluent. However, no significant difference was found between the ligation group and the nonligation group. (3) Similar findings were obtained when old rats were used. (4) Although basal levels of enzymes were almost the same in nonligated old and young adults rats, taurocholate injection into the pancreatic duct in old rats resulted in a significant depression of enzymes compared to that in young adult rats. In the ligation group, pancreatic enzymes in the portal venous effluent following taurocholate injection tended to be lower in old rats than in young adult rats. The results were histologically supported in that various degrees of fibrosis were found in the pancreata of old rats.
Molecular cloning of a human neuroD from a neuroblastoma cell line specifically expressed in the fetal brain and adult cerebellum.
Several neuron-specific cDNAs were identified using large-scale collection of 3'-directed partial cDNA sequences from a human neuroblastoma cell line. One of such cDNAs encoded a protein homologous to the mouse NeuroD. The mouse NeuroD, a basic helix-loop-helix (bHLH) protein seems to function as a differentiation factor for neurogenesis, as the gene is transiently expressed in postmitoic differentiating neurons. The human counterpart has a bHLH domain completely identical to that of the mouse NeuroD. But its expression was not only in the fetal brain but also in the adult cerebellum. The result of cross-species in situ hybridization also showed the transcripts were detected in the granule cell layer of the adult mouse cerebellum. The results suggest that the human as well as the mouse neuroD may play some important functions not only in the fetal brain but also in the fetal brain but also in the matured neurons of the cerebellum.
Extensive resection with selective cerebral perfusion for a lung cancer invading the aortic arch.
An extensive operation for lung cancer invading the aortic arch is reported. A 66-year-old man presented the recent onset of hoarseness. Chest computed tomography and magnetic resonance imaging demonstrated a tumor of the Botallo lymph node invading the aortic arch. Left pneumonectomy with combined resection of the aortic arch was performed with the use of brain-isolated cardiopulmonary bypass. The aortic arch was resected and replaced by an artificial graft. Pathological examination revealed a primary lesion of adenocarcinoma in the left upper lobe and contiguous lymph node involvement, pT4N2M0. He was discharged and followed as an outpatient, however he died of miswallowing 10 months later. Such an extensive operation may be of value in selected patients.
Transurethral interstitial laser coagulation for benign prostatic hyperplasia: treatment outcome and quality of life.
OBJECTIVE: To assess the efficacy and safety of transurethral interstitial laser coagulation (ILC) in the treatment of benign prostatic hyperplasia (BPH). PATIENTS AND METHODS: From December 1993 to March 1995, 61 patients (mean age 69.7 years, range 55-89) with symptomatic BPH were treated with ILC. A neodymium: YAG laser was used in combination with specially designed interstitial thermotherapy light-guides. The tip of the light guide was inserted repeatedly into each lobe of the prostate transurethrally, under direct vision. The number of fibre placements depended on the size and configuration of the gland. The prostatic urethra was preserved during the procedure. Treatment outcome was evaluated using the International Prostatic Symptom Score (IPSS), measurement of urinary flow rate and post-void residual urine volume (PVR). The disease-specific quality of life (QOL) was assessed using a QOL assessment score and a BPH impact index. Independently of the symptom assessment, a self-reporting questionnaire was completed 3 months after treatment to determine the patients' satisfaction with the treatment and their sexual function. RESULTS: Among the 31 patients followed for 6 months, the mean IPSS decreased significantly, from 18.9 at baseline to 7.7 (59% improvement; P < 0.001), the mean peak flow rate increased from 6.7 mL/s to 10.0 mL/s (49% improvement; n = 29; P < 0.001), the mean PVR decreased from 119 mL to 29 mL (76% improvement; n = 28, P < 0.001) and the mean prostate volume decreased significantly, from 37.1 mL to 31.6 mL (15% reduction at 3 months; n = 52, P < 0.001). There was a steady and progressive improvement in both the QOL assessment and the BPH impact index scores at 3 and 6 months. More than 90% of the patients reported satisfaction with the treatment and none reported the new onset of erectile dysfunction. There were no serious side-effects, except for two cases of loss of ejaculation. CONCLUSIONS: The early clinical results suggest that the ILC procedure is a safe and effective less-invasive treatment for BPH that appears to have favourable effects on the patients' quality of life.
Laparoscopic ureterolysis for retrocaval ureter.
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Microwave coagulation therapy for hepatocellular carcinoma.
BACKGROUND & AIMS: Surgical resection is not always feasible in patients with hepatocellular carcinoma. Microwave coagulation therapy has been used as an alternative to resection, and its efficacy has been evaluated. METHODS: Nineteen patients with unresectable hepatocellular carcinoma underwent microwave coagulation therapy through laparotomy (n = 12), laparoscopy (n = 5), or thoracotomy (n = 2) because of advanced liver cirrhosis and/or intrahepatic metastases. One nodule was treated in 13 patients, tumor size ranged from 5 to 90 mm. Patient outcomes were studied. RESULTS: Microwave coagulation therapy created a reproducible regional necrosis. Fourteen patients underwent potentially curative treatment; the remaining 5 patients underwent palliative treatment (n = 4) or incomplete tumor coagulation (n = 1). Of the 31 nodules treated, 28 underwent complete tumor ablation. Only 2 patients undergoing laparoscopic microwave coagulation therapy developed local recurrence. The coagulated area subsequently shrank. Patients showed rapid recovery without hepatic dysfunction. Thirteen patients, including 2 long-term survivors, are alive either without tumor (n = 10; 14-64 months) or with tumor (n = 3; 17-22 months). Six patients died of hepatocellular carcinoma (n = 4) or liver insufficiency (n = 2). CONCLUSIONS: This preliminary study suggests the efficacy of microwave coagulation therapy, including safety and potential curability, in patients with hepatocellular carcinoma with advanced liver cirrhosis and multifocal or central tumors.
Prevention of hydrogen peroxide damage by soybean saponins to mouse fibroblasts.
Soybean saponin is one of several soybean glycosides. Recently, new soybean saponins which possess the DDMP (2,5-dihydroxy-6-methyl-2,3-dihydro-4H-pyran-4-one) moiety have been detected. Soyasaponin beta g of these new soybean saponins was shown to inhibit hydrogen peroxide damage to mouse fibroblast cells. Not only the new saponin but also soyasaponin I, which has lost the DDMP moiety from soyasaponin beta g, was tested and showed higher inhibition in this assay. In order to investigate the relationship between the effect and chemical structure, glycyrrhizin, which has a similar chemical structure to soyasaponin I, was also tested and exhibited the same effect as soyasaponins beta g and I. Soyasaponin Ab, a major authentic bisdesmosidic saponin that exists only in the soybean hypocotyl, was also tested and exhibited the highest inhibition of hydrogen peroxide damage among the four saponins. It was concluded that water-soluble soybean saponins protected the cells from damage by hydrogen peroxide.