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Biomedical subjects

T Nakano

Publications and source records attributed to T Nakano.

At least 163 records · Page 9Linked to original sources

Involvement of a nuclear-encoded basic helix-loop-helix protein in transcription of the light-responsive promoter of psbD.

In the chloroplast psbD light-responsive promoter (LRP), a highly conserved sequence exists upstream from the bacterial -10/-35 elements. Multiple sequence-specific DNA binding proteins are predicted to bind to the conserved sequence as transcription factors. Using yeast one-hybrid screening of an Arabidopsis cDNA library, a possible DNA binding protein of the psbD LRP upstream sequence was identified. The protein, designated PTF1, is a novel protein of 355 amino acids (estimated molecular weight of 39.6) that contains a basic helix-loop-helix DNA binding motif in the predicted N-terminal region of the mature protein. Transient expression assay of PTF1-GFP fusion protein showed that PTF1 was localized in chloroplasts. Using the modified DNA sequence in the one-hybrid system, the ACC repeat was shown to be essential for PTF1 binding. The rate of psbD LRP mRNA accumulation was reduced in a T-DNA-inserted Arabidopsis ptf1 mutant. Compared with wild-type plants, the mutant had pale green cotyledons and its growth was inhibited under short-day conditions. These results suggest that PTF1 is a trans-acting factor of the psbD LRP.

Amino Acid Sequence↗

[Clinical evaluation of an immunochromatography test for rapid diagnosis of influenza].

We evaluated a rapid diagnostic kit that detects influenza type A and B viral antigens by immunochromatography, Quick Vue Influenza Test (Quidel Corp., San Diego, CA, USA), with 425 specimens collected from patients with influenza-like symptoms at three hospitals between January and March 2001. The specimens included 184 nasal aspirates, 140 nasal swabs, and 101 throat swabs. The test correctly identified 179 of the 204 culture positive specimens and 203 of the 221 culture negative specimens; the sensitivity and specificity compared with the culture were 87.7% and 91.9%, respectively. The sensitivity of the test was 92.6% (112/121) for nasal aspirates, 83.7% (41/49) for nasal swabs, and 76.5% (26/34) for throat swabs, which is similar to the results for conventional rapid enzyme immunoassay kits for influenza virus infection. The sensitivity and specificity of the QuickVue Influenza Test were equivalent to those of Flu OIA (BioStar, Inc., Boulder, CO, USA), with the agreement of 84.2%. Although the QuickVue Influenza Test does not differentiate between influenza A and B viruses, the easy-to-use kit detects both types in the physician's office, allowing physicians to make a decision on prescription of neuraminidase inhibitor therapy during the initial visit.

Evaluation Studies as Topic↗

[Clinical characterization of blaIMP positive gram-negative rods isolated cases].

We detected the metallo-beta-lactamase gene blaIMP positive strains of the gram-negative rods (GNR) isolated in Oita Medical University Hospital between 1993 and 1999 and studied the clinical characteristics of patients infected or colonized with blaIMP positive GNR. 25 strains (20 Pseudomonas aeruginosa and 5 Serratia marcescens) were detected and most of them were isolated from urinary samples after 1997. In the studies of antimicrobial susceptibility, some strains had sensitivity to aztreonum or imipenem although most of the strains showed multidrug resistance. When blaIMP positive GNR were isolated from patients, these strains were thought to have caused infection in 88% of the patients. About half of the patients were over 65 years old and had malignant diseases. Most of the patients had inserted urinary tract catheters, intratracheal tube or intravernous catheters. It was suggested that the insertion of the catheters were related to infection of blaIMP positive GNRs. Two patients were not treated with any antibiotics before the isolation of blaIMP positive GNRs although more than half of the patients were administered carbapenems and cephems. Most of strains were isolated in the same department and showed the same genotype by pulsed field gel electrophoresis.

Bacterial Proteins↗

Evaluation of accumulation of hepatitis C virus mutations in a chronically infected chimpanzee: comparison of the core, E1, HVR1, and NS5b regions.

Four hepatitis C virus genome regions (the core, E1, HVR1, and NS5b) were amplified and sequenced from yearly samples obtained from a chronically infected chimpanzee over a 12-year span. Nucleotide substitutions were found to accumulate in the core, E1, and HVR1 regions during the course of chronic infection; substitutions within the NS5b region were not detected for the first 8 years and were found to be minimal during the last 4 years. The rate of accumulation of mutations in the core and E1 regions, based on a direct comparison between the first 1979 sequence and the last 1990 sequence, was 1.120 x 10(-3), while phylogenetic ancestral comparison using the 12 yearly sequences showed a rate of 0.816 x 10(-3) bases per site per year. Temporal evaluation of the sequences revealed that there appeared to be periods in which substitutions accumulated and became fixed, followed by periods with relative stasis or random substitutions that did not persist. Synonymous and nonsynonymous substitutions within the core, E1, and HVR1 regions were also analyzed. In the core and E1 regions, synonymous substitutions predominated and gradually increased over time. However, within the HVR1 region, nonsynonymous substitutions predominated but gradually decreased over time.

Animals↗

Cross talk between prostacyclin and nitric oxide under shear in smooth muscle cell: role in monocyte adhesion.

We tested the hypothesis that at sites of vascular damage, vessel homeostasis is maintained through the cross talk of shear-induced production of prostacyclin and nitric oxide (NO) in vascular smooth muscle cells (VSMC). Confluent A7r5 cells derived from rat aortic VSMC and mesenteric VSMC were exposed to shear stress at 15 dyn/cm(2) for 90 min with the use of a cone-plate device, and productions of prostacyclin and NO were examined. Shear stress increased cumulative production of prostacyclin by 3- to 3.5-fold and that of NO by 6- to 7.5-fold. Western blot analysis showed that inducible NO synthase protein was expressed after shear stress in both types of VSMC. Inhibition of NO synthase enhanced the shear-induced production of prostacyclin from 40 to 60%. Shear-induced production of NO was suppressed by 70% after treatment with 10(-4) M of indomethacin. A7r5 cells adhesiveness for monocytes was suppressed by 50% after shear stress. This suppression was abolished by pretreatment with 10(-4) M of indomethacin, whereas inhibition of NO synthase only minimally inhibited it. We conclude that there is a cross talk of shear-induced production of prostacyclin and NO in VSMC. At sites of vascular damage, prostacyclin synthesis may prevent monocyte adhesiveness for VSMC through the concomitant enhancement of NO production.

Animals↗

Phosphatidylinositol 3-OH kinase-Akt/protein kinase B pathway mediates Gas6 induction of scavenger receptor a in immortalized human vascular smooth muscle cell line.

The growth arrest-specific gene 6 encodes a secreted protein, Gas6, which was originally identified as the ligand of a receptor, Axl, with tyrosine kinase activity. The class A scavenger receptor (SRA) mediates lipid uptake into cells, leading to the formation of foam cells, an important step in atherogenesis. Although Gas6 induces SRA expression, the underlying mechanism is not clear. In this report, we show that the Gas6-induced expression of SRA was mediated by the phosphatidylinositol 3-OH kinase (PI3-kinase)-serine/threonine kinase (Akt/protein kinase B [PKB]) pathway involving Akt phosphorylation. This pathway was activated by exposure to Gas6. Furthermore, the effect of Gas6 was abrogated by wortmannin, a specific inhibitor of PI3-kinase. We also demonstrated that the constitutively active form of Akt enhanced activity of the SRA promoter but that the dominant-negative mutant of Akt completely abolished the expression of SRA after treatment with Gas6. These results show that the PI3-kinase-Akt/PKB pathway participates in Gas6-induced SRA expression and suggests that the activation of Akt/PKB plays an important role in Gas6-induced atherosclerosis and foam cell formation in human vascular smooth muscle cells.

Androstadienes↗

Mitochondrial coupling factor 6 as a potent endogenous vasoconstrictor.

We demonstrated recently that coupling factor 6, an essential component of the energy-transducing stalk of mitochondrial ATP synthase, suppresses the synthesis of prostacyclin in vascular endothelial cells. Here, we tested the hypothesis that coupling factor 6 is present on the cell surface and is involved in the regulation of systemic circulation. This peptide is present on the surface of CRL-2222 vascular endothelial cells and is released by these cells into the medium. In vivo, the peptide circulates in the vascular system of the rat, and its gene expression and plasma concentration are higher in spontaneously hypertensive rats (SHRs) than in normotensive controls. Elevation of blood pressure with norepinephrine did not affect the plasma concentration of coupling factor 6. Intravenous injection of recombinant peptide increased blood pressure, apparently by suppressing prostacyclin synthesis, whereas a specific Ab to coupling factor 6 decreased systemic blood pressure concomitantly with an increase in plasma prostacyclin. Interestingly, the antibody's hypotensive effect could be abolished by treating with the cyclooxygenase inhibitor indomethacin. These findings indicate that mitochondrial coupling factor 6 functions as a potent endogenous vasoconstrictor in the fashion of a circulating hormone and may suggest a new mechanism for hypertension.

Amino Acid Sequence↗

Increase of cGMP, cADP-ribose and inositol 1,4,5-trisphosphate preceding Ca(2+) transients in fertilization of sea urchin eggs.

Transient increases, or oscillations, of cytoplasmic free Ca(2+) concentration, [Ca(2+)](i), occur during fertilization of animal egg cells. In sea urchin eggs, the increased Ca(2+) is derived from intracellular stores, but the principal signaling and release system involved has not yet been agreed upon. Possible candidates are the inositol 1,4,5-trisphosphate receptor/channel (IP(3)R) and the ryanodine receptor/channel (RyR) which is activated by cGMP or cyclic ADP-ribose (cADPR). Thus, it seemed that direct measurements of the likely second messenger candidates during sea urchin fertilization would be essential to an understanding of the Ca(2+) signaling pathway. We therefore measured the cGMP, cADPR and inositol 1,4,5-trisphosphate (IP(3)) contents of sea urchin eggs during the early stages of fertilization and compared these with the [Ca(2+)](i) rise in the presence or absence of an inhibitor against soluble guanylate cyclase. We obtained three major experimental results: (1) cytosolic cGMP levels began to rise first, followed by cADPR and IP(3) levels, all almost doubling before the explosive increase of [Ca(2+)](i); (2) most of the rise in IP(3) occurred after the Ca(2+) peak; IP(3) production could also be induced by the artificial elevation of [Ca(2+)](i), suggesting the large increase in IP(3) is a consequence, rather than a cause, of the Ca(2+) transient; (3) the measured increase in cGMP was produced by the soluble guanylate cyclase of eggs, and inhibition of soluble guanylate cyclase of eggs diminished the production of both cADPR and IP(3) and the [Ca(2+)](i) increase without the delay of Ca(2+) transients. Taken together, these results suggest that the RyR pathway involving cGMP and cADPR is not solely responsible for the initiating event, but contributes to the Ca(2+) transients by stimulating IP(3) production during fertilization of sea urchin eggs.

Adenosine Diphosphate Ribose↗

Deficiency of phospholipase C-gamma1 impairs renal development and hematopoiesis.

Phospholipase C-gamma1 (PLC-gamma1) is involved in a variety of intracellular signaling via many growth factor receptors and T-cell receptor. To explore the role of PLC-gamma1 in vivo, we generated the PLC-gamma1-deficient (plc-gamma1(-/-)) mice, which died of growth retardation at embryonic day 8.5-9.5 in utero. Therefore, we examined plc-gamma1(-/-) chimeric mice generated with plc-gamma1(-/-) embryonic stem (ES) cells for further study. Pathologically, plc-gamma1(-/-) chimeras showed multicystic kidney due to severe renal dysplasia and renal tube dilation. Flow cytometric analysis and glucose phosphate isomerase assay revealed very few hematopoietic cells derived from the plc-gamma1(-/-) ES cells in the mutant chimeras. However, differentiation of plc-gamma1(-/-) ES cells into erythrocytes and monocytes/macrophages in vitro was observed to a lesser extent compared with control wild-type ES cells. These data suggest that PLC-gamma1 plays an essential role in the renal development and hematopoiesis in vivo.

Animals↗

Level of plasma tissue factor pathway inhibitor is inversely correlated with intraarterial diastolic pressure in subjects who underwent coronary angiography.

There are only a few studies of the relationship between hemostatic abnormalities and intraarterial pressure, so the present study investigated the association of various newer lipid and hemostatic variables with intraarterial pressure levels. Levels of total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol, triglyceride, lipoprotein-(a), remnant-like particle cholesterol, cholesteryl ester transfer protein, uric acid, blood glucose, fibrinogen, free form of tissue factor pathway inhibitor (TFPI), C-reactive protein, serum amyloid A protein, anti-Chlamydia pneumoniae immunoglobulin G and immunoglobulin A, and apolipoproteins (apo) A-I, B, and E were measured in 176 patients who underwent diagnostic coronary angiography. Intraarterial blood pressure was determined from central aortic pressure using a standard fluid-filled catheter-external transducer system. Multivariate regression analyses showed that TFPI level was the only independent factor associated with aortic diastolic pressure. The linear regression equation demonstrated a significant negative correlation of TFPI level with aortic diastolic pressure (r=-0.395, p=0.0011). With respect to the association with other parameters, the TFPI level showed significant correlations between the HDL-C level and the apo A-I level, both in the overall patients and in the patients with coronary artery stenosis. This is the first evidence that the level of the plasma free form of TFPI is inversely correlated to aortic diastolic pressure.

Adult↗

Multiple pulmonary emboli with pulmonary hypertension caused by effort thrombosis and effective balloon venoplasty of the subclavian vein.

A 36-year-old woman with effort thrombosis of the subclavian vein associated with multiple pulmonary emboli was successfully treated with local thrombolysis of the subclavian vein using a pulse-spray catheter and systemic anticoagulation. Balloon venoplasty of the residual stenosis of subclavian vein was carried out and in follow-up venography 6 months later, there was no restenosis, and the patient has been asymptomatic for 12 months. Pulmonary embolism is not a rare complication of upper extremity deep vein thrombosis and should be managed as aggressively as lower extremity deep vein thrombosis.

Adult↗

Cytokinin-induced gene expression in cultured green cells of Nicotiana tabacum identified by fluorescent differential display.

The cell growth and plastid development of cultured green tobacco cells were maintained by the phytohormone cytokinin. After subculture into cytokinin-free medium, when cytokinin treatment was resumed, physiological changes induced by cytokinin were analyzed. Changes in chlorophyll biosynthesis and photosynthetic gene expression were observed 1 week after cytokinin induction, and changes in cell growth were observed 2 weeks after cytokinin induction. Two cytokinin-induced genes (cig) were isolated from these cells using the fluorescent differential display technique. Northern analysis confirmed that expression of these cig was induced by both natural and synthetic cytokinins. The expression of cig1 was also induced by abscisic acid, and its cDNA sequence was similar to the proline dehydrogenase gene. The expression of cig2 is specific to cytokinin and is not induced by other phytohormones. The amino acid sequence encoded by cig2 is similar to the GDP/GTP exchange factor eIF2B, which regulates translation initiation. The expression of these cig suggests a complex induction system involving cytokinin and other phytohormones.

Amino Acid Sequence↗

First-trimester ultrasonographic investigation of cardiovascular anatomy in thoracoabdominally conjoined twins.

Options for the treatment of thoracoabdominally conjoined twins are dependent on the anatomy of the cardiovascular system. It is important to increase the accuracy of diagnosis of conjoined twins with a fused heart. Color Doppler imaging performed in a 23-year-old nulliparous Japanese woman at 12 weeks of gestation revealed synchronized blood flow in 2 aortic arches arising from a single heart. The patient underwent a therapeutic abortion, and the diagnosis of conjoined twins with a fused heart was confirmed. Thus, color Doppler imaging is useful for investigating the cardiovascular anatomy in conjoined twins suspected of having a fused heart, even in an early gestational age.

Abdomen↗

Neonatal nucleated red blood cell counts in twins.

We counted nucleated red blood cells (NRBC) per 100 white blood cells (WBC) in the umbilical cord blood from 98 twins born to 49 women with uncomplicated twin pregnancies at > or = 34 weeks of gestation to better characterize NRBC in twins. Twelve women with monochorionic (MC) placentas and 37 with dichorionic (DC) placentas gave birth at 36.7 +/- .9 and 36.5 +/- 2 weeks of gestation, respectively. All twins were born with an Apgar score of > or = 7 at 1 min. Log10 (NRBC/100 BC) in 98 twins exhibited a nearly normal distribution, and was significantly associated with gestational age for both MC (r = -0.457, p = 0.025) and DC twins (r = - 0.275, p = 0.018), and with birth weight for both MC (r = -0.682, p < 0.001) and DC twins (r = -0.336, p = 0.003). Log10 (NRBC/100 WBC) tended to be larger in smaller twins than in larger twins in the MC group, and significantly larger in smaller twins than in larger twins in the DC group (p < 0.05). Intertwin difference in Log10 (NRBC/100 WBC) was defined as the value of Log10 (NRBC/100 WBC) of the smaller twin minus Log10 (NRBC/100 WBC) of the larger twin, and became greater with increasing intertwin difference in birth weight (r = 0.411, p = 0.003). These findings suggest that neonatal NRBC reflected gestational age and birth weight in twins. This preliminary observation using a small number of twins suggests that the smaller twin may have experienced a relative lack of oxygen compared with the larger twin in utero.

Adult↗

Embryonic stem cell.

Mouse embryonic stem (ES) cells are the cells that possess pluripotential differentiation activity into not only all somatic cells but also germ cells. Genetic alteration of mouse ES cells can be easily achieved and such genetic modification can be introduced into the animal, since ES cells are differentiated into germ cells in vivo. This technology enables us to analyze the function of any particular genes of interest in mice. And in vitro differentiation induction of mouse ES cells into various cell lineages, such as blood cells, neural cells, and cardiac muscle cells, has been studied. In vitro hematopoietic differentiation experiments were carried out most extensively and can be regarded as a model system of induction. Recently, human ES cells have been established. Many scientists, clinicians and even mass media have entertained the idea that human ES cells can be used after changing the cells into lineage-specific stem cells or progenitor cells such as hematopoietic stem cells and neural progenitor cells.

Animals↗

Three patients with isolated adrenocorticotropin deficiency presenting with neuroleptic malignant syndrome-like symptoms.

We report 3 patients with isolated adrenocorticotropin (ACTH) deficiency presenting with neuroleptic malignant syndrome (NMS)-like symptoms. All patients were in their 60's or 70's and showed consciousness disturbance, a high-grade fever, extrapyramydal signs, and muscle enzyme elevations, which met the criteria for NMS. Also, they all showed hyponatremia induced by isolated ACTH deficiency. In addition to the standard therapy for NMS, corticosteroid supplement therapy was effective in all patients. There thus appear to be subjects with isolated ACTH deficiency among patients presenting with NMS-like symptoms, and adrenal and pituitary function should be checked in NMS patients with hyponatremia.

Adrenocorticotropic Hormone↗

Hyperbaric oxygen for anorexia nervosa.

Hyperbaric oxygen was given to a patient with anorexia nervosa who had developed postoperative ileus, resulting in not only improvement in ileus, but also enhancement of intestinal movement, inducing the feeling of hunger, and thereby increasing food ingestion. Hyperbaric oxygen may be effective as an initial treatment for anorectic patients showing severe bloating and resistance to food ingestion.

Adolescent↗