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Biomedical subjects

H Nakano

Publications and source records attributed to H Nakano.

At least 127 records · Page 7Linked to original sources
PubMed2001

TT virus genotype changes frequently in multiply transfused patients with hemophilia but rarely in patients with chronic hepatitis C and in healthy subjects.

BACKGROUND: TT virus (TTV), a novel DNA virus, was originally thought to be transmitted by transfusion. However, nonparenteral transmission is recently suspected to be a major mode of transmission. To investigate the possibility of reinfection with TTV in multiply transfused patients and to evaluate the significance of transfusion transmission of TTV in patients with hemophilia, serial changes in TTV genotype were investigated in three groups. STUDY DESIGN AND METHODS: Serial changes in TTV genotype were investigated in 16 multiply transfused patients with hemophilia, 16 age-matched patients with chronic hepatitis C, and 16 age-matched healthy subjects. RESULTS: Mixed infection with multiple TTV genotypes was common in all groups. However, changes in TTV genotype were frequent in patients with hemophilia (15/16; 93.8%) but rare in patients with chronic hepatitis C and in healthy subjects (each group: 1/16; 6.3%). CONCLUSION: Changes in TTV genotype were frequently observed in multiply transfused patients with hemophilia but not in patients with chronic hepatitis or in healthy subjects without risk of transfusion transmission. This difference may suggest that exposure to TTV or even reinfection occurs frequently in patients with hemophilia, which could be evidence of transfusion transmission of TTV in this population.

Adolescent↗
PubMed2001

Isolation and characterization of a bovine blastocyst-derived trophoblastic cell line, BT-1: development of a culture system in the absence of feeder cell.

We established a trophoblastic cell line, bovine trophoblast-1 (BT-1), derived from in vitro matured and fertilized blastocyst. While several trophoblastic cell lines have been previously reported using feeder cell, BT-1 could be cultured in the absence of feeder cell. BT-1 was cultured for more than 18 months (over 75 passage) in the absence of feeder cells, using bovine endometrial fibroblast-conditioned medium (fibroblast-conditioned medium). We found that the cell growth was accelerated in fibroblast-conditioned medium. In bromodeoxyuridine incorporation analysis, BT-1 cells growth rate in fibroblast-conditioned medium was about two-fold higher than that in conventional medium. Furthermore, fibroblast-conditioned medium accelerated attachment of BT-1 cells to culture dishes following plating. BT-1 showed epithelial morphology and expressed cytokeratin. During continuous culture, cells accumulated fluid under the cell sheet and form dome-like structure that eventually transformed into free floating vesicles. Reverse transcription polymerase chain reaction analysis and immunoblot analysis demonstrated that BT-1 cells expressed interferon-tau as well as placental lactogen (PL). Immunofluorescence analysis demonstrated that a small number of cells were PL-positive, and these cells were binucleate. The BT-1 trophoblastic cell line could serve as a powerful model system for the study of trophoblast cell lineage and proliferation.

Animals↗
PubMed2001

Effectiveness of laparoscopic gonadectomy using abdominal wall lift method on Turner's syndrome patients with 45, X/46, XY mosaicism.

We present a Turner's syndrome patient with a 45, X/46, XY mosaicism who underwent a prophylactic laparoscopic gonadectomy using the abdominal wall lift method. The patient was a 14-year-old phenotypic girl who was referred for an examination of primary amenorrhea. She had already been found to have Turner's syndrome with 45, X/46, XY mosaicism. After an extensive discussion with the patient and her family regarding her high risk for developing a gonadoblastoma, a laparoscopic bilateral salpingo-oophorectomy using the abdominal wall-life method was performed. Laparoscopy using the abdominal wall lift method has an advantage over CO2 pneumoperitoneum method for patients with Turner's syndrome when it is difficult to intubate because of a webbed neck or a shortened trachea.

Adolescent↗
PubMed2001

The effects of capsaicin cream on prostaglandin-induced allodynia.

UNLABELLED: Although intradermal injection of capsaicin produces acute pain and secondary hyperalgesia, long-term topical application of capsaicin cream has been used as a medication for pain relief in various pain conditions. We previously reported that intrathecal administration of prostaglandin (PG) E(2) and PGF(2alpha) into mice induced touch-evoked pain (allodynia) through capsaicin-sensitive and capsaicin-insensitive afferent fibers, respectively. To clarify the mechanism of an analgesic effect by capsaicin cream, here we applied it to the tail and hind paws of mice and investigated its effects on PGE(2)- and PGF(2alpha)-induced allodynia. Twenty-four-hour pretreatment of mice with 0.025% or 0.05% capsaicin cream markedly alleviated allodynia induced by PGE(2), but not by PGF(2alpha). These results suggest that the topical application of capsaicin cream modulates capsaicin-sensitive afferents and ameliorates allodynia evoked by PGE(2) at the spinal level. IMPLICATIONS: Topical application of capsaicin cream alleviates touch-evoked pain induced by the intrathecal administration of prostaglandin E(2). This study may provide a rationale for the use of capsaicin cream as a therapeutic drug for pain relief.

Animals↗
PubMed2001

Protection against Fas-mediated and tumor necrosis factor receptor 1-mediated liver injury by blockade of FADD without loss of nuclear factor-kappaB activation.

OBJECTIVE: To investigate the role of FADD (Fas-associated protein with death domain) in Fas and tumor necrosis factor receptor 1 (TNFR1)-mediated hepatic injury and inflammatory response in vivo. SUMMARY BACKGROUND DATA: Fas and TNFR1 are cell surface molecules that trigger apoptosis or inflammation on engagement by a specific ligand or antibody. FADD is recruited to the cytoplasmic domain of these receptors on their activation and works as a common mediator to induce apoptosis. It is known that a blockade of FADD can inhibit apoptosis mediated by Fas or TNFR1 in vitro. However, it is not known whether the blockade can prevent organ injury and whether the inflammatory cascade is affected in vivo. METHODS: A FADD deletion mutant lacking the death effector domain was introduced into mice by transduction with an adenovirus vector, and the effect of this FADD dominant negative mutant was examined in several liver injury models. RESULTS: Hepatic injury induced by anti-Fas monoclonal antibody or tumor necrosis factor (TNF)-alpha plus D-galactosamine was markedly ameliorated by the FADD dominant negative transduction, which abrogated the death rate. Further, the FADD dominant negative transduction efficiently blocked T cell- mediated concanavalin A-induced hepatitis while not affecting TNF-alpha production or TNF-alpha-induced nuclear factor-kappaB activation in the liver. CONCLUSIONS: These results provide the basis for a novel therapeutic modality in which an unfavorable apoptotic process can be inhibited without affecting a favorable response for liver regeneration; this would be relevant to the clinical treatment of acute and chronic liver diseases as well as to some inflammatory disorders with hypercytokinemia, such as sepsis.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Analysis of allelic imbalance in patients with colorectal cancer according to stage and presence of synchronous liver metastases.

OBJECTIVE: To investigate the relationship between number and location of allelic imbalances (AI) and local tumor progression according to Astler-Coller classification. SUMMARY BACKGROUND DATA: Spontaneous errors in DNA replication (i.e., allelic imbalance or microsatellite instability) have been suggested to play an important role in carcinomatous transformation as reflecting alterations of gene function. METHODS: One hundred two consecutive patients with colorectal carcinoma undergoing surgical resection were included in this study. Patients were distributed according to the Astler-Coller classification as stages A (n = 7), B1 (n = 15), B2 (n = 24), C (n = 31), and D (n = 25). Fluorescent polymerase chain reaction was performed on frozen tumor, normal colon mucosa, and blood DNA at 35 microsatellite markers. Allelic imbalance frequency was compared with tumor staging. RESULTS: The percentage of AI was significantly higher in stage D than in A/B1 and B2. In addition, the percentage of AI was significantly higher in 10 synchronous colorectal liver metastases than in stage A/B1 and B2 tumors. However, the allelotyping revealed a subgroup of A/B1 tumors with a high AI frequency. Statistical analysis showed that the presence of AI at microsatellites D1S305, D2S138, D3S1282, D17S790, and D22S928 presented a significantly positive correlation with stages. CONCLUSION: The frequency of AI significantly correlates with tumor progression of colorectal cancer. Primary tumors with synchronous colorectal liver metastases showed a higher percentage of AI, suggesting that a frequency of AI greater than 35% with this selection of markers indicates a high risk of local progression and of development of metastases.

Adult↗
PubMed2001

Mechanical failure of unsupported Huckstep intramedullary nail in malignant bone tumor reconstruction.

Seventeen segmental resections of diaphyseal tumors and five knee resection arthrodeses were reconstructed using the Huckstep nail with intercalary bone grafts (fibula), cementation, and ceramic and titanium spacers. Although the bone defects were 0 to 25.5 cm in length (mean, 13.1 cm), all patients had relief of pain and were able to move alone with a wheelchair or a cane. Nail breakage occurred in four patients who had reconstruction surgery using a ceramic spacer (four patients without intercalary fibula graft and one patient with intercalary fibula graft). The nail survival rate was significantly better in the patients with reinforcement by vascularized fibular graft (100% at 5 years and 75% at 10 years; n = 8) than in the patients without reinforcement by vascularized fibular graft (87.5% at 3 years and 0% at 5 years; n = 14). Huckstep nailing is a useful option for reconstruction of large bone defects in diaphyseal tumors and knee resection arthrodesis. It should be used in combination with a vascularized fibula graft to prevent mechanical failure and to achieve durability of limbs with defects from primary bone tumors. Huckstep nailing with nonbiologic augmentation is good for palliative surgery for bone metastases in patients with a shorter expected survival rate.

Adolescent↗
PubMed2001

Rapid, quantitative PCR monitoring of growth of Clostridium botulinum type E in modified-atmosphere-packaged fish.

A rapid, quantitative PCR assay (TaqMan assay) which quantifies Clostridium botulinum type E by amplifying a 280-bp sequence from the botulinum neurotoxin type E (BoNT/E) gene is described. With this method, which uses the hydrolysis of an internal fluoregenic probe and monitors in real time the increase in the intensity of fluorescence during PCR by using the ABI Prism 7700 sequence detection system, it was possible to perform accurate and reproducible quantification of the C. botulinum type E toxin gene. The sensitivity and specificity of the assay were verified by using 6 strains of C. botulinum type E and 18 genera of 42 non-C. botulinum type E strains, including strains of C. botulinum types A, B, C, D, F, and G. In both pure cultures and modified-atmosphere-packaged fish samples (jack mackerel), the increase in amounts of C. botulinum DNA could be monitored (the quantifiable range was 10(2) to 10(8) CFU/ml or g) much earlier than toxin could be detected by mouse assay. The method was applied to a variety of seafood samples with a DNA extraction protocol using guanidine isothiocyanate. Overall, an efficient recovery of C. botulinum cells was obtained from all of the samples tested. These results suggested that quantification of BoNT/E DNA by the rapid, quantitative PCR method was a good method for the sensitive assessment of botulinal risk in the seafood samples tested.

Animals↗
PubMed2001

Myxococcus xanthus mokA encodes a histidine kinase-response regulator hybrid sensor required for development and osmotic tolerance.

A gene, mokA, encoding a protein with similarities to histidine kinase-response regulator hybrid sensor, was cloned from a Myxococcus xanthus genomic library. The predicted mokA gene product was found to contain three domains: an amino-terminal input domain, a central transmitter domain, and a carboxy-terminal receiver domain. mokA mutants placed under starvation conditions exhibited reduced sporulation. Mutation of mokA also caused marked growth retardation at high osmolarity. These results indicated that M. xanthus MokA is likely a transmembrane sensor that is required for development and osmotic tolerance. The putative function of MokA is similar to that of the hybrid histidine kinase, DokA, of the eukaryotic slime mold Dictyostelium discoideum.

Amino Acid Sequence↗
PubMed2001

Ambient temperature modulates hypoxic-induced changes in rat body temperature and activity differentially.

When rats, acclimated to an ambient temperature (T(a)) of 29 degrees C, are exposed to 10% O(2) for 63 h, the circadian rhythms of body temperature (T(b)) and level of activity (L(a)) are abolished, T(b) falls to a hypothermic nadir followed by a climb to a hyperthermic peak, L(a) remains depressed (Bishop B, Silva G, Krasney J, Salloum A, Roberts A, Nakano H, Shucard D, Rifkin D, and Farkas G. Am J Physiol Regulatory Integrative Comp Physiol 279: R1378-R1389, 2000), and overt brain pathology is detected (Krasney JA, Farkas G, Shucard DW, Salloum AC, Silva G, Roberts A, Rifkin D, Bishop B, and Rubio A. Soc Neurosci Abstr 25: 581, 1999). To determine the role of T(a) in these hypoxic-induced responses, T(b) and L(a) data were detected by telemetry every 15 min for 48 h on air, followed by 63 h on 10% O(2) from rats acclimated to 25 or 21 degrees C. Magnitudes and rates of decline in T(b) after onset of hypoxia were inversely proportional to T(a), whereas magnitudes and rates of T(b) climb after the hypothermic nadir were directly proportional to T(a). No hyperthermia, so prominent at 29 degrees C, occurred at 25 or 21 degrees C. The hypoxic depression of L(a) was least at 21 degrees C and persisted throughout the hypoxia. In contrast, T(a) was a strong determinant of the magnitudes and time courses of the initial fall and subsequent rise in T(b). We propose that the absence of hyperthermia at 21 and 25 degrees C as well as a persisting hypothermia may protect the brain from overt pathology.

Abdomen↗
PubMed2001

GABAergic modulation of ventilation and peak oxygen consumption in obese Zucker rats.

Obesity is often associated with a reduced ventilatory response and a decreased maximal exercise capacity. GABA is a major inhibitory neurotransmitter in the mammalian central nervous system. Altered GABAergic mechanisms have been detected in obese Zucker rats and implicated in their hyperphagic response. Whether altered GABAergic mechanisms also contribute to regulate ventilation and influence exercise capacity in obese Zucker rats is unknown and formed the basis of the present study. Eight lean [317 +/- 18 (SD) g] and eight obese (450 +/- 27 g) Zucker rats were studied at 12 wk of age. Ventilation at rest and ventilation during hypoxic (10% O(2)) and hypercapnic (4% CO(2)) challenges were measured by the barometric method. Peak O(2) consumption (VO(2 peak)) in response to a progressive treadmill test to exhaustion was measured in a metabolic treadmill. Ventilation and VO(2 peak) were assessed after administration of equal volumes of DMSO (vehicle) and the GABA(A) receptor antagonist bicuculline (1 mg/kg). In lean animals, bicuculline administration had no effect on ventilation and VO(2 peak). In obese rats, bicuculline administration significantly (P < 0.05) increased resting ventilation (465 +/- 53 and 542 +/- 72 ml. kg(-1). min(-1) for control and bicuculline, respectively), ventilation during exposure to hypoxia (899 +/- 148 and 1,038 +/- 83 ml. kg(-1). min(-1) for control and bicuculline, respectively), and VO(2 peak) (62 +/- 3.7 and 67 +/- 3.5 ml. kg(-0.75). min(-1) for control and bicuculline, respectively). However, in obese Zucker rats, ventilation in response to hypercapnia did not change after bicuculline administration (608 +/- 96 vs. 580 +/- 69 ml. kg(-1). min(-1)). Our findings indicate that endogenous GABA depresses ventilation and limits exercise performance in obese Zucker rats.

Animals↗
PubMed2001

Flow-mediated release of nitric oxide in isolated, perfused rabbit lungs.

The effects of changing perfusate flow on lung nitric oxide (NO) production and pulmonary arterial pressure (Ppa) were tested during normoxia and hypoxia and after N(G)-monomethyl-L-arginine (L-NMMA) treatment during normoxia in both blood- and buffer-perfused rabbit lungs. Exhaled NO (eNO) was unaltered by changing perfusate flow in blood-perfused lungs. In buffer-perfused lungs, bolus injections of ACh into the pulmonary artery evoked a transient increase in eNO from 67 +/- 3 (SE) to 83 +/- 7 parts/billion with decrease in Ppa, whereas perfusate NO metabolites (pNOx) remained unchanged. Stepwise increments in flow from 25 to 150 ml/min caused corresponding stepwise elevations in eNO production (46 +/- 2 to 73 +/- 3 nl/min) without changes in pNOx during normoxia. Despite a reduction in the baseline level of eNO, flow-dependent increases in eNO were still observed during hypoxia. L-NMMA caused declines in both eNO and pNOx with a rise in Ppa. Pulmonary vascular conductance progressively increased with increasing flow during normoxia and hypoxia. However, L-NMMA blocked the flow-dependent increase in conductance over the range of 50-150 ml/min of flow. In the more physiological conditions of blood perfusion, eNO does not reflect endothelial NO production. However, from the buffer perfusion study, we suggest that endothelial NO production secondary to increasing flow, may contribute to capillary recruitment and/or shear stress-induced vasodilation.

Acetylcholine↗
PubMed2001

Role of airway nitric oxide on the regulation of pulmonary circulation by carbon dioxide.

The effects of hypercapnia (CO(2)) confined to either the alveolar space or the intravascular perfusate on exhaled nitric oxide (NO), perfusate NO metabolites (NOx), and pulmonary arterial pressure (Ppa) were examined during normoxia and progressive 20-min hypoxia in isolated blood- and buffer-perfused rabbit lungs. In blood-perfused lungs, when alveolar CO(2) concentration was increased from 0 to 12%, exhaled NO decreased, whereas Ppa increased. Increments of intravascular CO(2) levels increased Ppa without changes in exhaled NO. In buffer-perfused lungs, alveolar CO(2) increased Ppa with reductions in both exhaled NO from 93.8 to 61.7 (SE) nl/min (P < 0.01) and perfusate NOx from 4.8 to 1.8 nmol/min (P < 0.01). In contrast, intravascular CO(2) did not affect either exhaled NO or Ppa despite a tendency for perfusate NOx to decline. Progressive hypoxia elevated Ppa by 28% from baseline with a reduction in exhaled NO during normocapnia. Alveolar hypercapnia enhanced hypoxic Ppa response up to 50% with a further decline in exhaled NO. Hypercapnia did not alter the apparent K(m) for O(2), whereas it significantly decreased the V(max) from 66.7 to 55.6 nl/min. These results suggest that alveolar CO(2) inhibits epithelial NO synthase activity noncompetitively and that the suppressed NO production by hypercapnia augments hypoxic pulmonary vasoconstriction, resulting in improved ventilation-perfusion matching.

Animals↗
PubMed2001

Serotonergic modulation of ventilation and upper airway stability in obese Zucker rats.

To elucidate the role of serotonin in the maintenance of normal breathing and upper airway (UA) patency in obesity, we studied the effects of systemic administration of ritanserin, a serotonin (5-HT) 2A and 2C receptor antagonist, on ventilation (V E) during room air breathing and during hypoxic (10% O2) and hypercapnic (4% CO2) ventilatory challenges in awake young (6-8 wk) and older (7-8 mo) obese and lean Zucker (Z) rats. Older obese Z rats adopted a more rapid shallow breathing pattern compared with older lean rats. The administration of ritanserin (1 mg/kg intraperitoneally) to older obese rats resulted in a reduction in V E (439 +/- 35 [SD] to 386 +/- 41 ml/kg/min, p < 0.01), a decrease in respiratory rate, a prolongation of inspiratory time, and an increase in V O2 (16.4 +/- 1.7 to 18.2 +/- 1.9 ml/kg(0.75)/min, p < 0.05) during room air breathing. By comparison, it had little effect on ventilation in young lean and obese Z or older lean Z rats. Ritanserin also had no effect on ventilatory responses to either hypoxia or hypercapnia in young or older lean and obese Z rats. The collapsibility of the isolated UA was examined in older Z rats. The pharyngeal critical pressure (Pcrit) of older obese rats was significantly greater than that of lean rats (p < 0.05), indicating that obese rats have more collapsible UA than lean rats. The administration of ritanserin significantly increased Pcrit in older obese rats (-1.6 +/- 0.3 to -0.8 +/- 0.2 cm H2O, p < 0.01) and in lean rats (-3.1 +/- 1.0 to -2.4 +/- 0.6 cm H2O, p < 0.05). We suggest that the 5-HT(2A/2C) receptor subtype plays an important role in the maintenance of UA stability and normal breathing in obesity, and we speculate that older obese Z rats may have augmented serotonergic control of UA dilator muscles as a mechanism to prevent pharyngeal collapse.

Age Factors↗
PubMed2001

Interleukin-18 in human milk.

We analyzed IL-18 levels of human milk. Colostrum contained significantly higher levels of IL-18 compared with early milk and mature milk. By stepwise multiple linear regression analysis, preterm delivery and pregnancy complications of mothers significantly correlated with high levels of IL-18 in human milk (p = 0.0007 and 0.0018, respectively). There was a significant correlation between the levels of IL-18 and soluble Fas ligand in colostrum (p = 0.0003). IL-18 was detected in actively secreting epithelial cells in lactating mammary gland by immunohistochemical staining. These results suggest that IL-18 in colostrum plays an important role in host defense of high-risk neonates.

Base Sequence↗
PubMed2001

Dosage effect of minor arginyl- and isoleucyl-tRNAs on protein synthesis in an Escherichia coli in vitro coupled transcription/translation system.

In Escherichia coli mRNA, the arginine codons AGA/AGG and the isoleucine codon AUA are rarely used with frequencies of about 0.35% and 0.41%, respectively. Six genes with a different number of these codons were expressed in an E. coli in vitro coupled transcription/translation system, which contained either tRNA prepared from E. coli cells carrying a plasmid with argU and ileX genes encoding rare tRNAs (tRNA(arg)(AGA/AGG) and tRNA(ile)(AUA)), designated codon-plus tRNA, or normal tRNA from cells lacking the plasmid. Genes having a low number of the rare codons, such as genes encoding chloramphenicol acetyltransferase and anti-gp120 single-chain Fv (artificially constructed to remove rare codons), were expressed at similar levels using with both tRNA preparations. On the other hand, the use of codon-plus tRNA increased the expression levels of genes having a relatively large number of the rare codons, including genes encoding archaeal proteins, green fluorescent protein of jelly fish origin, and a single-chain Fv of mouse origin, by about 20% higher than that using normal tRNA.

Journal Article↗