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Biomedical subjects

K Okubo

Publications and source records attributed to K Okubo.

At least 19 recordsLinked to original sources
PubMed1999

Paradoxical decrease of an adipose-specific protein, adiponectin, in obesity.

We isolated the human adipose-specific and most abundant gene transcript, apM1 (Maeda, K., et al., Biochem. Biophys. Res. Commun. 221, 286-289, 1996). The apM1 gene product was a kind of soluble matrix protein, which we named adiponectin. To quantitate the plasma adiponectin concentration, we have produced monoclonal and polyclonal antibodies for human adiponectin and developed an enzyme-linked immunosorbent assay (ELISA) system. Adiponectin was abundantly present in the plasma of healthy volunteers in the range from 1.9 to 17.0 mg/ml. Plasma concentrations of adiponectin in obese subjects were significantly lower than those in non-obese subjects, although adiponectin is secreted only from adipose tissue. The ELISA system developed in this study will be useful for elucidating the physiological and pathophysiological role of adiponectin in humans.

Adiponectin↗
PubMed1998

Cloning and developmental expression of the murine homolog of doublecortin.

While analyzing active genes in neonatal mouse hippocampus by quantitative 3'-cDNA collection, we identified a highly conserved murine homolog of doublecortin, the causative gene of X-linked lissencephaly (XLIS) and subcortical laminar heterotopia (SCLH) syndrome. The m-doublecortin cDNA contains nearly 8 kb 3' UTR homologous to hs-doublecortin and it was mapped to the X chromosome. The expression of m-doublecortin is limited to the developing CNS, especially the cortical plate, supporting that XLIS/SCLH syndrome is associated with an arrest of neuronal migration in the cerebral cortex. The m-doublecortin mRNA was absent in the ventricular zone where neuronal precursors proliferate, and interestingly it was found in various brain structures that are not typically affected in patients with this syndrome.

Amino Acid Sequence↗
PubMed1998

A mesangium-predominant gene, megsin, is a new serpin upregulated in IgA nephropathy.

Mesangial cells play an important role in maintaining a structure and function of the glomerulus and in the pathogenesis of glomerular diseases. To identify a specific gene expressed in human mesangial cells, we used a rapid large-scale DNA sequencing and computerized data processing to compare the transcripts in cultured human mesangial cells with various different cells and organs. Using this novel approach, we discovered a new mesangium-predominant gene termed "megsin." We obtained a full-length cDNA clone of megsin, which coded for a novel 380-amino acid protein. Amino acid homology search revealed that megsin belonged to the serpin (serine protease inhibitor) superfamily. The amino acid sequences in the reactive loop site of megsin showed characteristic features of functional serpins. Northern blot and reverse-transcribed PCR analyses of various tissues and cells demonstrated that megsin was predominantly expressed in human mesangial cells. In situ hybridization studies showed the megsin expression in the mesangium of normal glomeruli, while it increased in the expanded mesangium of glomeruli from patients with IgA nephropathy with the degree of mesangial proliferation. Here we report a new human mesangium-predominant gene that may function as an inhibitory serpin in normal and abnormal biological processes of glomerulus.

Amino Acid Sequence↗
PubMed1998

Expression profile of active genes in granulocytes.

A number of genes active in granulocytes have been intensively studied as to the function of their products and their expression controls. However, the intensities and relative order of these gene activities have not been studied. This report describes an expression profile of 748 different species of active genes in human peripheral granulocytes obtained by analyzing a 3'-directed cDNA library that faithfully represents the mRNA population in the source cells. A significant fraction (20.3% of the total) of the expressed genes in granulocytes consisted of nuclear proteins such as DNA binding proteins, of secretory proteins such as cytokines, and of membrane proteins such as major histocompatibility complex (MHC) proteins and receptors. By comparing this expression profile with 11 profiles similarly obtained with unrelated human cells/tissues, we discovered 10 novel genes that are likely to act specifically in granulocytes. Comparison of this expression profile with that obtained with granulocytoids widely used as a granulocyte model by inducing a cultured promyelocytic leukemia cell line HL60 showed similarities and dissimilarities of gene expressions.

Adult↗
PubMed1998

A novel SCG10-related gene uniquely expressed in the nervous system.

We have isolated a novel cDNA (HiAT3: hippocampus abundant transcript 3) in the course of screening for genes that are preferentially expressed in neonatal mouse hippocampus using random 3'-directed cDNA sequencing approach. It encodes a 180-aa protein that has high similarity to SCG10, a neuron-specific negative regulator of microtubule dynamics during neurite outgrowth. The expression of HiAT3 is limited to neurons and peaks about 1 week after birth. The identification of HiAT3 suggests that there may be an elaborate destabilizing regulation for microtubule dynamics in neurons in addition to the stabilizing effect of multiple microtubule-associated proteins (MAPs).

Amino Acid Sequence↗
PubMed1998

Identification of a novel gene marker specific for epithelial cells by utilizing a 3'-directed cDNA library.

To achieve reliability of molecular diagnosis using reverse transcription-PCR (RT-PCR), we established a unique method to search for a novel gene marker specific for colonic epithelial cells. Of eight candidate genes selected from a 3'-directed cDNA library in colonic mucosa, two genes were expressed in normal mucosa and cancer of the colon but not in either normal lymph node or normal liver tissue. Known sequences of these genes were reported to be located in the 3' noncoding region, and an additional sequence just upstream to gs04094 (one of the candidate genes) was determined. According to the newly identified sequence, we designed a new set of primers so that we could distinguish the DNA fragment amplified in RT-PCR from that in genomic PCR. RT-PCR using these primers demonstrated that gs04094 was expressed in all of 10 primary colon cancers and 4 liver metastases from colon cancer but in none of 5 normal lymph nodes, 10 peripheral blood samples, and 2 normal liver tissues. Sensitivity of this method was so high as to detect gs04094 mRNA in 10(-6) microg of colon cancer RNA per 1 microg of normal lymph node RNA. Thus, our strategy to search for a novel gene marker using 3'-directed cDNA library proved to be highly efficient.

Animals↗
PubMed1998

Oguchi disease with sectoral retinitis pigmentosa harboring adenine deletion at position 1147 in the arrestin gene.

PURPOSE: To report a Japanese patient with Oguchi disease and sectoral retinitis pigmentosa harboring a homozygous adenine deletion at position 1147 (1147delA) in the arrestin gene. METHOD: Case report. RESULTS: In both eyes, golden discoloration with Mizuo-Nakamura phenomenon and tapetoretinal degeneration of the fundus were exhibited. Electroretinography showed abnormal a-wave and absent b-wave. The presence of 1147delA in the arrestin gene was demonstrated. CONCLUSIONS: Our case provides further evidence of the close association of 1147delA in the arrestin gene in Japanese patients with Oguchi disease. Coexpression of both phenotypes of Oguchi disease and retinitis pigmentosa may suggest the possible involvement of additional defects of genes encoding the phototransduction proteins.

Adenine↗
PubMed1998

Interstitial laser coagulation for management of benign prostatic hyperplasia: a Japanese experience.

PURPOSE: The principle of interstitial laser coagulation is to shrink the prostate by generating intraprostatic necrosis without damaging the urethra or causing tissue sloughing. The clinical efficacy and durability of interstitial laser coagulation in the treatment of benign prostatic hyperplasia (BPH) were evaluated. MATERIALS AND METHODS: From December 1993 to June 1996, 76 patients with symptomatic BPH were treated with interstitial laser coagulation. A neodymium:YAG laser was used in combination with a specially designed interstitial thermotherapy light guide. The tip of the light guide was inserted into each lobe of the prostate transurethrally under direct vision. All evaluations were made at baseline and then 1, 3, 6 and 12 months after therapy. Treatment outcome was evaluated by International Prostate Symptom Score (I-PSS), flow rate and post-void residual urine volume. Disease specific quality of life was assessed via a quality of life assessment score and a BPH impact index. Independent of symptom assessment, a self-reporting questionnaire was prepared at 3 months postoperatively regarding satisfaction with treatment and sexual function. RESULTS: Among 44 patients followed to 12 months the mean I-PSS significantly decreased from 20.4 at baseline to 7.4, representing 64% improvement (p <0.001). Peak flow rate increased by 50% from a preoperative average of 7.4 to 11.1 ml. per second at 12 months in 42 patients (p <0.001). The post-void residual volume decreased by 57% from 102 to 44 ml. at 12 months in 40 cases (p <0.001). Steady and progressive improvement was observed on quality of life assessment and BPH impact index scores at 3, 6 and 12 months. No patients reported new onset of erectile dysfunction. No serious side effects were observed, except for loss of ejaculation in 3 cases and seminal vesicle abscess in 1. Only 6 patients (8%) required re-treatment for persisting obstructive symptoms during 12 months of followup. A recent change in methods towards more aggressive treatment plausibly influenced the outcomes to require less repeat treatment. CONCLUSIONS: After the interstitial laser coagulation procedure satisfactory results were obtained and improvement lasted through 12 months. Although the optimal number of fiber placements for each prostate is not known, more aggressive treatment appears to provide better outcomes.

Aged↗
PubMed1998

Functional quantitative analysis of the genome in cultured human mesangial cells. Technical note.

For normal physiological function, each cell tightly regulates gene expression in a specific fashion so that critical proteins are synthesized in a well-coordinated manner. Therefore, it is very important to uncover which genes are expressed in specific cells. Recent technological advances combined with rapid large-scale DNA sequencing and computerized data processing have allowed us to investigate the expression levels of a variety of transcripts in the mesangial cells, a target of injury in many forms of glomerulonephritis. Utilizing a large scale sequencing of a 3'-directed cDNA library, which allows us to avoid variable cloning efficiencies reflecting the size of cDNA, we investigated expression profiles of various molecules in cultured human mesangial cells. Among the 1,193 sequenced clones, 688 (57.7%) appeared more than once (redundant sequence group), representing 203 different species. Thirty-nine of these appeared more than three times. The most abundant mRNA was that of fibronectin, which consisted of 3.9% of the total mRNA population. Except for mitochondrial or ribosomal genes, calcyclin came next (2.5%), followed by two cytoskeletal genes, gamma-actin gene and calpactin 1 light chain gene, in addition to an amyloid precursor protein homolog (0.7%). In conclusion, we performed a molecular biological quantification of transcripts in mesangial cells. Fibronectin was the most abundantly expressed, followed by calcyclin, gamma-actin, calpactin 1 light chain, and an amyloid precursor protein homolog. We also discovered some candidate genes specific for human mesangial cells. The expression profile of the transcripts serves as an important tool in understanding the biological properties of mesangial cells.

Actins↗
PubMed1998

Isolation of genes identified in mouse renal proximal tubule by comparing different gene expression profiles.

An expression profile is a list based on a large scale sequencing of 1000 cDNA clones, showing the expressed genes and the abundance of their transcripts in a given cell or tissue (Okubo K et al: Nature Genet 2:173, 1992). We constructed an expression profile of mouse renal proximal tubules (PT) carefully isolated by microdissection in order to characterize its gene expression. Altogether 1000 clones were analyzed; there were 646 types of transcripts in PT, among which 196 were identical or homologous to the previously reported genes. The most abundant transcript was kidney-androgen regulated protein. By comparing the expression profile of PT with those obtained from other sources, several genes were identified only in PT. They included known transcripts and transcripts that were not homologous to the known genes. Three (GS4001, 3991, and 4059) of the non-homologous genes were analyzed by Northern blotting and in situ hybridization, and GS4001 and 4059 were predominantly expressed in the kidney, whereas GS3991 was detected in the liver as well as in the kidney. The sequence analysis of the full-size cDNAs demonstrated that GS4001 was a new member of aspartic proteinases and GS4059 was a novel gene. It also revealed that GS3991 was a mouse homologue of SA gene known to be expressed in PT. The expression profile of mouse PT and its comparison with those of other tissues and cells provide an alternate way of isolating genes predominantly expressed in PT, and also provides probes to study the molecular mechanisms of gene expression in the kidney.

3T3 Cells↗
PubMed1998

Value of the free to total prostate specific antigen ratio and prostate specific antigen density for detecting prostate cancer in Japanese patients.

BACKGROUND: This study evaluated the free to total serum prostate specific antigen (f/t PSA) ratio and prostate specific antigen density (PSAD) in detecting prostate cancer in Japanese males with a PSA level between 2.5 and 20.0 ng/mL in a community-based urology practice. METHODS: Twenty-six patients with clinically localized prostate cancer and 44 patients with histologically-proven benign prostatic hyperplasia (BPH) were studied. The serum levels of free PSA (fPSA) and total (t) PSA were determined using a chemiluminescent enzyme immunoassay. The f/t PSA ratio was calculated by dividing the fPSA value by the total PSA value and was compared with the PSA and PSAD via the receiver operating characteristic (ROC) curves. RESULTS: Patients with prostate cancer had a significantly lower f/t PSA ratio than patients with BPH. The PSAD was a superiordiagnostic tool over PSA (P< 0.01) when analyzed by ROC curves. The f/t PSA ratio was also superior to PSA, but lacked significance (P=0.12), and similarly, the PSAD was superior, but not significant, to the f/t PSA ratio. Using a cut-off value of 0.19, the PSAD had a sensitivity of 81% and a specificity of 82%. With a cut-off value of 14.0%, the f/t PSA ratio had a sensitivity of 81% and a specificity of 66%. CONCLUSION: This study showed that PSAD alone improved cancer detection significantly better than PSA. However, it is still unclear whether the f/t PSA ratio is superior to PSA or PSAD in the discrimination between BPH and prostate cancer in Japanese male patients.

Aged↗
PubMed1998

Incidence of lymph node metastasis and its impact on long-term prognosis in clinically localized prostate cancer.

BACKGROUND: Pelvic lymph node dissection (PLND) is an important staging method for men with clinically localized prostate cancer. We report our experience with staging PLND and the impact of lymph node metastasis on long-term prognosis. METHODS: One hundred forty-eight consecutive patients who underwent staging PLND for clinically localized prostate cancer were retrospectively studied. Patients were evaluated for the presence and number of lymph node metastases, treatment (prostatectomy vs. radiotherapy), and endocrine therapy, and analyzed with respect to disease progression and survival. The mean follow-up period was 52.9 months (range, 2.3 to 165.8 months). RESULTS: Thirty-two patients (21.6%) had pelvic lymph node metastases, the incidence of which markedly decreased from 32.3% in 1982 to 1987 to 6.7% in 1994 to 1997. The intervals to disease progression and cancer death were significantly shorter in patients with positive lymph nodes (P < 0.001). In stage D1 disease, patients who underwent a radical prostatectomy tended to be free of progression longer than those receiving radiotherapy or conservative therapy (P = 0.0546). Other factors, such as early endocrine therapy, the extent of lymph node involvement and the Gleason score of the primary tumor did not predict disease progression or survival. CONCLUSION: These data suggest a decreasing trend in the incidence of lymph node metastasis in the PSA era. Although longer disease-free intervals were observed in radical prostatectomy-treated patients, the impact of an aggressive approach to stage D1 disease awaits further studies.

Adenocarcinoma↗
PubMed1998

Ultrasensitive assay of prostate-specific antigen for early detection of residual cancer after radical prostatectomy.

OBJECTIVES: Perhaps the greatest value of PSA determination in the treatment of prostate cancer is in determining persistent disease after a radical prostatectomy. We investigated the ability of an ultrasensitive PSA assay to detect residual prostate cancer in men at risk for recurrence after a radical prostatectomy. METHODS: Using the Immulite third-generation PSA assay (detection limit, less than 0.003 ng/mL), and the standard IMx PSA assay, we determined PSA levels in 205 serum samples serially obtained from 34 men after a radical prostatectomy. The average days from surgery to serum sampling was 430 (range, 63 to 1296). Patients were classified as having nonaggressive or aggressive cancers, based on clinicopathologic findings. A biochemical relapse was arbitrarily defined. RESULTS: All 17 patients with nonaggressive cancers had PSA values of less than 0.02 ng/mL throughout the sampling period. Two of these patients (12%) had 2 or more consecutive PSA increases and were considered as a biochemical relapse. In contrast, 14 (82%) of 17 patients with aggressive cancers fit criteria of a biochemical relapse. All of the relapses were identified within 2 years after surgery. The IMx assay detected only 7 biochemical relapses during the same sampling period. CONCLUSIONS: Using the Immulite PSA assay, relapse detection times may be shortened allowing for most serological recurrences to be detected within 2 years after a radical prostatectomy. Patients with aggressive cancers may require frequent postoperative PSA determinations with a highly sensitive PSA assay which would allow early intervention when treatments for relapse are effective.

Aged↗
PubMed1998

Inhibitory effects of catecholamines and maternal stress on aromatase activity in the fetal rat brain.

OBJECTIVE: Aromatization in the the fetal brain is thought to be involved both in sex differentiation during early development and in adult sexual behavior. Although recently the relationship between aromatase and catecholamine has been discussed, the effect of stress on aromatase in the fetal brain has not been clarified. Therefore, in the present study, localization of aromatase and the inhibitory effects of catecholamines and maternal stress on aromatase activity in the fetal rat brain were examined. METHODS: Localization of aromatase cytochrome P-450 using a specific polyclonal antiserum against human placenta aromatase was examined, and the inhibitory effects of dopamine and norepinephrine on aromatase activity in vitro were studied. Further, the influences of intrauterine stress on aromatase activity in the prenatal rat brain were evaluated in vivo. RESULTS: Aromatase-immunoreactive neurons are located principally in the medial amygdaloid nucleus. Aromatase activity in the fetal rat brain was competitively inhibited by dopamine and norepinephrine, with Ki values of 120 microM and 100 microM, respectively. Aromatase activity in the fetal brain was significantly lower in stressed rats given 1.5% salt water (89.2 +/- 17.5 fmol/mg/hr; n = 4) (p < 0.05) than in the control group (123.1 +/- 10.0 fmol/mg/hr; n = 4). CONCLUSION: Aromatase activity in the prenatal rat brain is influenced by catecholamine metabolism during intrauterine stress.

Amygdala↗
PubMed1998

[A case of brain abscess accompanied with sudden-onset hemiplegia as initial manifestation].

A 58-year-old male experienced a sudden stroke-like onset of right hemiplegia and numbness of his right upper limb while engaged in his desk-work on April 7, 1997. He had a past history of diabetes mellitus and hyperlipidemia. On admission, he had no fever and the blood pressure was 140/70 mmHg. General physical examination was unremarkable. Neurological examination showed 4/5 strength of his right unilateral extremities and numbness of his right upper limb. Clinical features and computed tomography (CT) without contrast medium at the onset of hemiplegia suggested a stroke. Seven days after admission, his consciousness worsened and body temperature fluctuated between 37 and 38 degrees C. Subsequent Gd-enhanced magnetic resonance (MR) which demonstrated an irregular shaped ring-enhancement lesion and lumbar puncture 9 days after admission was compatible with the diagnosis of brain abscess. Surgical drainage confirmed the presence of brain abscess due to alpha-streptococcus. It improved following surgical drainage and antibiotic therapy with PAPM.BP 2 g/day and PIPC 4 g/day. An afebrile patient of sudden stroke-like onset may be a rarity to be added to the differential diagnosis of brain abscess.

Acute Disease↗