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Biomedical subjects

R Nakano

Publications and source records attributed to R Nakano.

At least 73 records · Page 4Linked to original sources
PubMed1997

A novel quinoline derivative, MS-209, overcomes drug resistance of human lung cancer cells expressing the multidrug resistance-associated protein (MRP) gene.

PURPOSE AND METHODS: MS-209 is a newly synthesized quinoline compound used orally to overcome human P-glycoprotein (Pgp)-mediated multidrug resistance (MDR). The multidrug resistance-associated protein (MRP) gene is thought to play an important role in MDR in lung cancer. To investigate whether MS-209 could also overcome MRP-mediated MDR, we examined the effect of the compound using a cytotoxicity assay on MDR1 gene-negative drug-selected MDR and wildtype lung cancer cells with various levels of MRP gene expression. The effects of MS-209 were compared with those of verapamil (VER) and cyclosporin A (CsA). The level of MRP gene expression in the cells was evaluated semiquantitatively by RT-PCR. For vincristine (VCR), intracellular accumulation of [3H]-VCR was measured with or without MS-209. RESULTS: In MDR UMCC-1/VP small-cell lung carcinoma cell line, 5 microM of MS-209 and VER enhanced the cytotoxicity of etoposide, doxorubicin (DOX) and VCR more than twofold, and completely reversed the resistance to VCR. The mean reversing effects of MS-209 on DOX and VCR were significantly stronger than those of VER and CsA. In wildtype non-small-cell lung carcinoma cells, the effects of MS-209 were almost equal to those of VER and CsA. The effect of these three agents correlated with the level of MRP gene expression. The MS-209-induced increase in intracellular accumulation of VCR was proportional to the level of MRP gene expression in these cells. CONCLUSION: Our results indicate that MS-209 is a potentially useful drug that can overcome MRP-mediated intrinsic and acquired MDR in human lung cancer.

Antineoplastic Agents↗
PubMed1997

A missense mutation in the SOD1 gene in patients with amyotrophic lateral sclerosis from the Kii Peninsula and its vicinity, Japan.

Unusually high incidences of amyotrophic lateral sclerosis (ALS) have been observed in the natives of the Kii Peninsula of Japan as well as the indigenous Chamorro people of Guam. Given the relatively high incidence of familial onset of the disease in the Kii Peninsula, we performed mutational analyses of the SOD1 gene of 23 patients (three familial cases and 20 sporadic cases) with ALS from the Kii Peninsula and its vicinity. In two of the 23 patients, we identified the same missense mutation (substitution of Thr for Ile 113) in exon 4 as a heterozygous state. The Ile 113Thr mutation in the SOD1 gene has been identified in some familial as well as sporadic cases with ALS, as a mutation with a low penetrance. This mutation has been reported to be associated with the formation of neurofibrillary tangles in an English family, which is a characteristic feature of ALS in the Kii Peninsula. These results suggest that the Ile113Thr mutation is a characteristic and relatively prevalent mutation in this area.

Adult↗
PubMed1997

Production of inhibin A and inhibin B in human ovarian sex cord stromal tumors.

OBJECTIVE: Our purpose was to examine the cellular localization of inhibin subunits and messenger ribonucleic acid expressions for the inhibin subunits and the serum levels of inhibin A and inhibin B in human ovarian sex cord stromal tumors. STUDY DESIGN: We examined the immunohistochemical localization of the inhibin subunits and the expression of the corresponding messenger ribonucleic acids by Northern blot analysis in a granulosa cell tumor and a Sertoli-Leydig cell tumor. We also measured serum concentrations of dimeric inhibin A and inhibin B by two-site enzyme-linked immunosorbent assay. RESULTS: Immunostaining specific for the inhibin alpha, betaA, and betaB subunits was observed in the granulosa cell tumor. In the Sertoli-Leydig cell tumor we observed immunostaining specific for the alpha subunit in Leydig tumor cells and that specific for the betaA subunit in Sertoli tumor cells and that specific for the betaB subunit in both tumor cells. Northern blot analysis revealed the presence of messenger ribonucleic acids for the alpha, betaA, and betaB subunits in the granulosa cell tumor and the Sertoli-Leydig cell tumor. The serum levels of dimeric inhibin A and inhibin B in patients were elevated preoperatively and decreased progressively after surgery. CONCLUSION: Our results suggest that inhibin A and inhibin B are produced by the human sex cord stromal tumors and that inhibins might be the useful markers of the tumors.

Adolescent↗
PubMed1997

Serum levels of inhibin A and inhibin B in women with normal and abnormal luteal function.

OBJECTIVE: To determine whether serum inhibin A and inhibin B concentrations are lower in patients with luteal dysfunction than in women with normal luteal function. METHODS: Serum samples were collected from seven healthy women with regular menstrual cycles. Serum samples on days +5 to +9 after the LH surge were collected from patients with luteal dysfunction. The diagnosis of luteal dysfunction was based on a luteal phase duration less than 11 days and a single midluteal progesterone level below 10 ng/mL. Serum levels of inhibin A, inhibin B, progesterone, estradiol (E2), FSH, and LH were measured. RESULTS: The serum inhibin A levels were increased toward the late follicular phase. The levels reached a maximum during the midluteal phase, followed by a fall during the late luteal phase. The serum inhibin B levels were high during the follicular phases and the early luteal phase. The levels decreased during the midluteal and late luteal phases. Serum levels (mean +/- standard error of the mean) of inhibin A in patients with luteal dysfunction were significantly lower than those in women during the midluteal phase (26.2 +/- 2.9 compared to 41.9 +/- 2.8 pg/mL; P < .01) in addition to the expected decrease in serum progesterone levels (6.3 +/- 0.7 compared to 14.7 +/- 1.2 ng/mL; P < .01). Serum inhibin B levels did not differ significantly between normal women and those with luteal dysfunction. There also were no significant differences in the E2, FSH, and LH levels. CONCLUSION: Levels of inhibin A, but not of inhibin B, may reflect the human luteal function.

Adult↗
PubMed1997

Splanchnic and extrasplanchnic arterial hemodynamics in patients with cirrhosis.

BACKGROUND/AIMS: This study was designed to assess the contribution of splanchnic and extrasplanchnic vascular hemodynamics to the hyperdynamic circulation in patients with cirrhosis. METHODS: Cardiac index and flow volume index and pulsatility index (PI) of superior mesenteric artery (SMA) and femoral artery (FA) were measured with Doppler ultrasonography in 40 controls and 86 patients with cirrhosis (Child-Pugh grade A=41, grade B=30, and grade C=15). Mean arterial pressure was also recorded to calculate systemic vascular resistance index. RESULTS: Systemic vascular resistance index was significantly lower in each Child-Pugh group than in controls. SMA blood flow index was significantly higher in each Child-Pugh group than in controls and the increase in SMA blood flow index paralleled the degree of liver dysfunction. SMA-PI was significantly lower in each Child-Pugh group than in controls and the decrease in SMA-PI paralleled the degree of liver dysfunction. FA blood flow index was slightly higher in Child-Pugh grade A patients and significantly higher in grade B patients than in controls, whereas grade C patients had normal FA blood flow index. FA-PI was significantly lower in grade A and grade B patients than in controls, whereas grade C patients had normal FA-PI. When all patients were examined together, SMA-PI significantly correlated with systemic vascular resistance index (r=0.69, p<0.01). In contrast, FA-PI did not significantly correlate with systemic vascular resistance index (r=0.15, p=0.18). CONCLUSIONS: Splanchnic arterial vasodilatation plays an important role in the pathogenesis of decreased systemic vascular resistance seen in patients with cirrhosis.

Analysis of Variance↗
PubMed1997

Effect of posture-induced blood volume expansion on systemic and regional hemodynamics in patients with cirrhosis.

BACKGROUND/AIMS: This study aimed to investigate the effects of posture-induced blood volume expansion on systemic and regional hemodynamics in patients with cirrhosis. METHODS: The mean arterial pressure, cardiac index, peripheral vascular resistance index, and flow volume index of the superior mesenteric artery (SMA) and femoral artery (FA) were measured in 10 patients with cirrhosis and portal hypertension and 10 controls after they had been standing for 2 h. Plasma atrial natriuretic peptide, plasma renin activity, and plasma glucagon levels were also determined. These measurements were repeated after 30 min and 60 min when the patients were recumbent. RESULTS: In the upright posture, systemic hemodynamics, FA blood flow index, plasma atrial natriuretic peptide level, and plasma renin activity level were similar in patients and controls. However, SMA blood flow index and plasma glucagon level were significantly higher in patients than in controls. On the assumption of the supine position, cardiac index and plasma atrial natriuretic peptide level significantly increased in the two groups, but the changes were greater in patients than in controls. Mean arterial pressure remained unchanged. The reduction in peripheral vascular resistance index was therefore greater in patients in controls. SMA and FA blood flow index increased significantly in the two groups, but the changes were greater in patients than in controls. Furthermore, SMA blood flow fraction (SMA blood flow index/cardiac index) was steady in controls, whereas it increased significantly in patients. In contrast, FA blood flow fraction (FA blood flow index/cardiac index) remained unchanged in the two groups. In patients, the change in peripheral vascular resistance index was correlated inversely with that of SMA blood flow index, but not with that of FA blood flow index. Plasma renin activity level dropped significantly, but the decline was similar in the two groups. Plasma glucagon level was not modified in either group. CONCLUSIONS: In patients with cirrhosis, splanchnic vasodilation appears to be present, even in the upright position, and further abnormal vasodilation occurs on recumbency-induced blood volume expansion. This abnormal shear-stress phenomenon observed in the splanchnic circulation seems to be mediated by a local vasodilator rather than a general vasodilator.

Blood Volume↗
PubMed1997

Novel method to investigate kinetics of rat skin cells by means of an occlusive dressing method using bromodeoxyuridine.

We developed a novel technique to detect S-phase skin cells by applying bromodeoxyuridine (BrdU) epicutaneously using an occlusive dressing (OD) method. BrdU was scarcely absorbed from the skin with a simple epicutaneous application, whereas the incorporation of BrdU was very well promoted with the use of our OD method. We applied BrdU on the backs of rats using this method and investigated the conditions required for an optimal response, with a special focus on the period of application, the concentration of BrdU used and vehicles suitable for the immunocytochemical staining of this agent. From these experiments, we were able to determine that an application time of at least 60 min was necessary to liable S-phase cells, a 2% concentration of BrdU was needed to obtain consistent labeling and aqueous vehicles are satisfactory solvents for BrdU preparations. Epidermal keratinocytes and S-phase cells in the upper portion of dermis were clearly labeled after either intraperitoneal injection of BrdU or after administration by means of the OD method. To ascertain whether this latter method could provide an effective alternative to intraperitoneal injection, we compared the labeling patterns of both methods with respect to the speed of migration of BrdU-labeled basal cells from the basal layer to the horny layer of epidermis. Using either of these two methods, basal keratinocytes were labeled immediately after administration. Three days after the first administration, BrdU-labeled cells were detected in the middle layer of the epidermis, but after 8 days, they were no longer evident in epidermal tissue. As another means of comparing both methods, we used antibody to proliferating cell nuclear antigen (PCNA) and compared the ratio of PCNA-positive basal cells to BrdU-labeled basal cells. The number of PCNA-positive cells was about 4.6 times greater than the number of BrdU-labeled basal cells by both methods. We concluded that the OD method could be used as a substitute for intraperitoneal injection in order to observe cell kinetics using bromodeoxyuridine.

Administration, Topical↗
PubMed1997

Control of the luteal function in humans.

Although luteinizing hormone (LH) of the anterior pituitary is considered primarily responsible for the initiation of luteinization in most species, the mechanisms governing the subsequent life and death of the corpus luteum vary among species. In women and in nonhuman primate, the corpus luteum derives its support from LH that must be continuously present. To date, the factors regulating the life span and endocrine activity of the corpus luteum in humans and primates are not completely understood. This article summarizes our study on luteinizing hormone and chorionic gonadotropin receptors in human corpora lutea during the menstrual cycle and pregnancy and the apoptosis of human corpora lutea during the menstrual cycle and pregnancy.

Apoptosis↗
PubMed1997

Increased laminin-1 expression in hydatidiform mole.

To investigate the aetiology of hydatidiform mole, laminin-1 expression was determined in human villous tissues obtained from normal pregnancies (n = 17) and complete hydatidiform moles (n = 10). Indirect immunofluorescent staining was performed to detect laminin-1, and Northern blot analysis was performed to assess expression of laminin mRNA. Serum concentrations of laminin P-1 were also measured. Immunohistochemical analysis revealed stronger staining of the trophoblastic basement membrane in hydatidiform mole than in normal pregnancy. Northern blot analysis revealed that villous expression of laminin mRNA was significantly increased in hydatidiform mole compared with normal pregnancy (P < 0.05). The serum laminin P-1 concentration was also significantly higher in those patients with hydatidiform mole than in normal pregnancy (P < 0.05). These results suggest that laminin-1 might play an important role in determining the pathophysiology and structure of hydatidiform mole. In addition, measurement of serum laminin P-1 in combination with human chorionic gonadotrophin might be useful in the diagnosis of hydatidiform mole, to evaluate the prognosis, and to detect the presence of metastatic or recurrent disease.

Adult↗
PubMed1997

Increase in the relative level of type V collagen in the placentae of patients with pre-eclampsia.

To obtain some insight into the extracellular matrix in the human placenta, we investigated the composition of collagens purified from the placentae of patients with pre-eclampsia and compared it with normal placentae. Collagen was extracted from the placentae of both normal and pre-eclampsia pregnancies during the third trimester. The relative amounts of various collagens were evaluated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The ratio of the intensity of the band corresponding to the alpha 1 (III) chain with that of the alpha 1 (I) chain in placentae of pre-eclampsia was significantly lower than in normal placentae (P < 0.05). In contrast, the ratio of the intensity of the band corresponding to the alpha 1 (V) chain with that of the alpha 1 (I) chain in placentae of pre-eclampsia was significantly higher than in normal placentae (P < 0.05). The results suggest that an increased level of type V collagen relative to type I collagen in the placentae of pre-eclampsia might be closely associated with the disturbance to trophoblastic cell functions and the supply of nutrients to the developing fetus necessary for the maintenance of pregnancy.

Adult↗
PubMed1997

Cloning of maize ferredoxin III gene: presence of a unique repetitive nucleotide sequence within an intron found in the 5'-untranslated region.

A genomic clone encoding the precursor of a non-photosynthetic ferredoxin (Fd III) from maize has been isolated and characterized. In comparison with the corresponding cDNA, the gene (fedIII) was found to be interrupted in the 5'-untranslated region by an intron consisting of 3,037 bp. About 80% of the total region of this intron is organized into four classes of tandemly repeated sequences with monomeric lengths of about 200 bp, 320 bp, 130 bp, and 90 bp. This unique intron organization is present in the fedIII gene of three related maize cultivars examined.

Amino Acid Sequence↗
PubMed1997

A nitrate-inducible ferredoxin in maize roots. Genomic organization and differential expression of two nonphotosynthetic ferredoxin isoproteins.

We have identified and characterized a nitrate-inducible ferredoxin (Fd) in maize (Zea mays L.) roots by structural analysis of the purified protein and by cloning of its cDNA and gene. In maize Fd isoproteins are encoded by a small multigene family, and the nitrate-inducible Fd was identified as a novel isoprotein, designated Fd VI, which differed from an Fd I to Fd V identified to date. In the roots of seedlings cultured without nitrate, Fd VI was undetectable. However, during the induction of the capacity for nitrate assimilation, the amount of Fd VI increased markedly within 24 h. Concurrently, the level of transcript for Fd VI increased, but more quickly, reaching a maximal level within 2 h with kinetics similar to those of nitrite reductase and Fd-NADP+ reductase. Fd III was constitutively expressed in roots, and no such changes at the protein and mRNA levels were observed during the nitrate induction. In the 5' flanking region of the gene for Fd VI only, we identified NIT-2 motifs, which are widely found in genes for enzymes related to nitrogen metabolism. These data indicate that Fd VI is co-induced with the previously characterized enzymes involved in nitrate assimilation, and they suggest that the novel Fd isoprotein, distinct from the constitutively expressed Fd, might play an important role as an electron carrier from NADPH to nitrite reductase and other Fd-dependent enzymes in root plastids.

Amino Acid Sequence↗
PubMed1997

Gene mutation analysis and quantitation of DNA topoisomerase I in previously untreated non-small cell lung carcinomas.

To elucidate whether gene alterations of topoisomerase I (topo I) exist in untreated non-small cell lung carcinomas (NSCLC), polymerase chain reaction-single strand conformation polymorphism analysis was performed in forty-four NSCLC tissue samples. Gene alterations of topo I were sought in three regions, near codons 361 and 363, 533, and 722 and 729, where point mutations have been found in resistant tumor cell lines selected by chronic camptothecin exposure. In addition, nuclear topo I contents were determined by immunoblotting. No mobility shifts were observed compared to the pattern observed in a normal control at any of the three regions in any sample, whereas topo I levels showed an approximately 12-fold variation. The variation is remarkably large compared to those seen in previous in vitro and in vivo studies. The results suggest that mutations of topo I may not contribute to intrinsic resistance of NSCLC to camptothecins, but low topo I levels may account, at least in part, for the resistance.

Adenocarcinoma↗
PubMed1997

Increased serum concentrations of type IV collagen and laminin associated with granulosa cell tumour of the ovary.

A 65 year old woman presented with an ovarian mass. Ultrasonography and computed tomography findings, and an increased serum oestrogen concentration were suggestive of an oestrogen producing ovarian tumour. The tumour was removed surgically and weighed 460 g. The pathological diagnosis was adult-type granulosa cell tumour. Strong immunohistochemical staining specific for type IV collagen and laminin was observed, and these components were localised to the pericellular region of the granulosa cells. The serum concentrations of these basement membrane components (measured by radioimmunoassay) were very high before surgery, but decreased rapidly thereafter. Serial measurement of type IV collagen and laminin, in conjunction with other tumour markers and oestrogen concentrations, might be helpful in evaluating prognosis of ovarian granulosa cell tumours, in detecting metastatic or recurrent lesions and in monitoring response to treatment.

Aged↗
PubMed1997

Effects of oestrogen on the extracellular matrix in the endometrium of postmenopausal women.

AIM: To obtain insight into the effects of oestrogen on extracellular matrix (ECM) in the postmenopausal endometrium. METHODS: The distribution of the components of the ECM, including collagen types I, III, IV, and VI, and laminin, was investigated in the human postmenopausal endometrium by an indirect immunofluorescence method with specific monoclonal antibodies and a polyclonal antibody. Collagens were also extracted from the endometrial tissues of postmenopausal women who had or had not been treated with oestrogen for three weeks. RESULTS: Immunohistochemical studies demonstrated that type I collagen was the predominant interstitial collagen, and that types III and VI collagens were absent or very sparsely distributed in the stroma of the postmenopausal endometrium. However, types I, III, and VI collagens were diffusely localised in the stroma of the postmenopausal endometrium after administration of oestrogen. Even though type IV collagen was not seen in the basement membrane of the endometrial glands in the endometrium of postmenopausal women in the absence of oestrogen treatment, both type IV collagen and laminin were localised exclusively in the basement membrane of the endometrial glands in the postmenopausal endometrium after three weeks of oestrogen treatment. The level of type III collagen relative to that of type I collagen was significantly increased (p < 0.01) in the endometrium of oestrogen treated postmenopausal women compared with non-treated postmenopausal women. CONCLUSIONS: Conjugated equine oestrogen might induce changes in the distribution of components and in the composition of the ECM in the endometrium of postmenopausal women.

Aged↗
PubMed1997

Apoptosis: gene-directed cell death. An overview.

Apoptosis, a term derived from the ancient Greek meaning a 'falling off, such as 'of leaves from a tree', is a physiologic cell death used by the body to delete unwanted cells without eliciting an immune response or inflammatory reaction. A hallmark of apoptosis is the activation of endonuclease that attacks the cell's genomic DNA at the linker regions that connect the nucleosomal units. Degradation of DNA produces DNA fragments in size multiples of 185 to 200 bp that can be observed as a distinct 'DNA ladder pattern'. Apoptotic cell death is gene-directed cell death.

Animals↗
PubMed1997

Apoptosis of human ovary and uterine endometrium during the menstrual cycle.

To investigate apoptotic changes in the ovary or uterine endometrium, we studied the cleavage of DNA in these tissues obtained from regularly cycling women by in situ analysis of DNA integrity and quantitative end labeling of DNA gel fractionation. In situ analysis of several sized atretic follicles of ovaries revealed that granulosa cells showed positive staining to some extent, however, these methods do not discriminate between cells undergoing apoptosis and those undergoing necrosis. Total DNA extracted from human corpora lutea (CL) of the early luteal phase contained predominantly high molecular weight DNA, whereas CL of the midluteal phase exhibited the appearance of DNA cleavage into low molecular weight ladders characteristic of apoptosis. Although apoptotic DNA cleavage of human CL increased from the midluteal phase to the late luteal phase, CL of early pregnancy did not exhibit apoptotic DNA fragmentation. Both large and small luteal cells were the primary cell type exhibiting DNA cleavage in human CL of the midluteal and late luteal phases and in regressive CL. Biochemical analysis of human endometrium revealed that the ladder pattern cleavage of DNA was identified at three different phases of the menstrual cycle, namely the early proliferative, late secretory, and menstrual phases. Cells undergoing apoptosis were scattered in the functional layer of the early proliferative endometrium, but not in the late proliferative phase to midsecretory phase: At the beginning of the late secretory phase, apoptosis reappeared in the stromal cells and spread gradually to almost all components of the functional layer. By contrast, cells in the basal layer showed no evidence of apoptosis throughout the menstrual cycle. The present findings suggest that: (1) human luteal regression may be mediated by apoptosis; (2) CL of early pregnancy may be rescued from luteolysis through inhibition of the occurrence of apoptotic luteal cell death, and (3) apoptosis occurs in specific populations of endometrial cells during the human endometrial cycle. In conclusion, apoptosis might play an important role in the regulation of the menstrual cycle in women.

Adult↗