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Biomedical subjects

Y Hashimoto

Publications and source records attributed to Y Hashimoto.

At least 433 records · Page 24Linked to original sources
PubMed1998

Effect of surfactant on respiratory failure associated with thoracic aneurysm surgery.

OBJECTIVE: To study the effects of surfactant administration on the left lung after surgical repair of descending aortic aneurysms on postoperative respiratory failure. DESIGN: Randomized, prospective, controlled study. SETTING: Clinical investigation. PATIENTS: Eleven patients with respiratory failure associated with thoracic aneurysm surgery. INTERVENTION: Eleven adult patients with acute respiratory failure (PaO2/FIO2 <300 torr [<40 kPa]) after surgical repair of descending aortic aneurysms. The artificial surfactant (30 mg/kg) was given to the operated side of the lung by intrabronchial instillation in six patients (surfactant group), whereas nothing was instilled in the other five patients (control group). MEASUREMENTS AND MAIN RESULTS: Hemodynamic parameters, blood gas, and peak inspiratory pressure were measured at the end of surgery, before surfactant instillation, and at 2, 6, 12, 24, and 48 hrs after surfactant instillation. At the end of surgery, the mean +/- SEM values of the PaO2/FIO2 ratio were 204 +/- 25 torr (27.2 +/- 3.3 kPa) in the surfactant group and 240 +/- 26 torr (32.0 +/- 3.5 kPa) in the control group. After 2, 6, 12, and 48 hrs, improvements in the PaO2/FIO2 ratios were observed in the surfactant group, whereas the control group showed no improvement. Two hours after surfactant instillation, the mean value in the PaO2/FIO2 ratio was significantly higher in the surfactant group (318 +/- 24 torr [42.4 +/- 3.2 kPa]) (p < .05) compared with the control group values (240 +/- 34 torr [32 +/- 4.5 kPa]). CONCLUSION: Surfactant administration immediately after surgery restored gas exchange in postoperative respiratory failure associated with thoracic aneurysm surgery.

Acute Disease↗
PubMed1998

Pharmacologic profile of TA-606, a novel angiotensin II-receptor antagonist in the rat.

This study was carried out to characterize a novel angiotensin II-receptor antagonist, TA-606, (3-pentyloxy) carbonyloxymethyl-5-acetyl-2-n-propyl-3-[2'(1H-tetrazole-5-yl) biphenyl-4-yl]methyl-4,5,6,7-tetrahydro imidazo [4,5-c] pyridine-4-carboxylate hydrochloride, which is a newly synthesized prodrug of 606A. In anesthetized rats, 606A inhibited angiotensin II-induced pressor response with a median inhibitory concentration (IC50) of 6 microg/kg, i.v., and was 8 times more potent than EXP3174, an active metabolite of losartan. Bioavailability of TA-606 was 11 times higher than that of 606A in Sprague-Dawley rats, with consistent hypotensive potencies in spontaneously hypertensive rats (SHRs). In conscious renal hypertensive rats (RHRs) and conscious SHRs, TA-606 lowered the blood pressure without any effects on the heart rate, and its effective dose for 30 mm Hg (ED30) values were 0.14 and 0.21 mg/kg, p.o., respectively. The effect of TA-606 lasted > 10 h in both models. Moreover, the effect of TA-606 was approximately 30 and 10 times more potent than those of losartan in RHRs and SHRs, respectively. TA-606 did not affect the blood pressure in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. TA-606 given for 12 weeks attenuated the development of hypertension in stroke-prone SHRs. These results indicate that TA-606 is a potent angiotensin II-receptor antagonist with antihypertensive efficacy. Thus TA-606 is suggested to be a possible useful agent in the treatment of hypertension.

Angiotensin Receptor Antagonists↗
PubMed1998

Sequences of ten circular ssDNA components associated with the milk vetch dwarf virus genome.

Milk vetch dwarf virus (MDV) is a member of the proposed genus Nanovirus, and its genome is composed of multiple, circular ssDNA components of about 1 kb. We have cloned and sequenced ten ssDNA components and designated them MDV-C1 to C10. Each DNA component contains one potential major open reading frame, and contains a putative stem-loop structure in the non-coding region. Notably, four components (C1, C2, C3 and C10) encode distinct replication-associated (Rep) proteins of 33 kDa, which show only limited (42-57%) amino acid identity. The six other components encode proteins with calculated molecular masses ranging from 12.7 to 19.7 kDa. Comparison of the sequences with those of other nanoviruses reveals that MDV is closely related to faba bean necrotic yellows virus (FBNYV) and subterranean clover stunt virus (SCSV). Six putative MDV genome products, including one Rep and five non-Rep proteins, show high (70.4-90.9%) amino acid identity to the corresponding six FBNYV proteins, whereas two other Rep proteins encoded by MDV-C2 and C3 are 82.3% and 73.0% identical to those encoded by SCSV-C2 and C6, respectively. These results indicate that MDV, FBNYV and SCSV have diverged from a common origin, which had multiple Rep components. In addition, the putative proteins encoded by MDV-C4 and its homologues contain a consensus retinoblastoma-binding motif, suggesting that they may be involved in controlling the host cell cycle.

Amino Acid Sequence↗
PubMed1998

The ecdysteroid UDP-glucosyltransferase gene of Autographa californica nucleopolyhedrovirus alters the moulting and metamorphosis of a non-target insect, the silkworm, Bombyx mori (Lepidoptera, Bombycidae).

The Autographa californica nucleopolyhedrovirus (AcMNPV) does not infect the silkworm and molecular studies on silkworm insusceptibility have not been performed. In cultured cells of the silkworm, the expression of viral genes has been reported. The expression of AcMNPV genes and their effect in vivo and in vitro was studied. In this study, the early gene, the ecdysteroid UDP-glucosyltransferase (egt) gene of AcMNPV, which inactivates the insect moulting hormone by sugar conjugation, was examined to determine whether it would alter the growth of the silkworm. Using wild-type (wt) AcMNPV, the egt gene deletion virus (vEGTDEL), and the virus carrying the egt promoter-lacZ cassette in vEGTDEL (vEGTZ), the egt promoter-driven expression in cultured cells and in nonproductive infection of the silkworm was characterized. Infection of cultured cells with vEGTZ at three different doses occurred in a single cell manner. When budded wt AcMNPV was injected into the fourth and fifth instar larvae, an increase in the amount of virus occurred and caused abnormal larval growth, which resulted in the prolongation or skipping of the larval instar, premature pupation, or death during the pupal stage. For infection of the fourth instar larvae, precocious metamorphosis was observed. When the same amount of vEGTDEL was injected, the alteration of growth did not occur. These results suggest that the egt gene was expressed in the primary infected cells of the silkworm, and that the EGT was secreted into the haemocoel, which significantly altered larval growth.

Animals↗
PubMed1998

Isolation and characterization of a temperature-sensitive mutant of Bombyx mori nucleopolyhedrovirus for a putative RNA polymerase gene.

Temperature-sensitive (ts) mutants of Bombyx mori nucleopolyhedrovirus (BmNPV), which exhibited no polyhedra formation at the non-permissive temperature of 33 degrees C, were produced using the base analogue 5-bromodeoxyuridine. A unique ts mutant, designated ts-S1, was characterized in terms of gene mutation and virulence in cultured cells and silkworm larvae. Mutant-infected BmN4 cells at 33 degrees C showed normal viral DNA synthesis but defective budded virus production and polyhedrin synthesis, suggesting the absence of late and very late gene expression. Silkworm larvae were injected with ts-S1 and reared at 33.5 degrees C. At 7 days post-injection, none of the larvae exhibited nucleopolyhedrosis but some possessed viral DNA, detected by PCR using virus-specific primers. Continued rearing of the larvae at a permissive temperature of 25 degrees C showed that, while most developed into normal adults, some developed nucleopolyhedrosis, indicating that the former larvae had aborted the virus infection during the course of rearing at 33.5 degrees C. No viral DNA was detected in the adults. Marker rescue tests to identify the lesion involved in the ts phenotype of ts-S1, and nucleotide sequencing of the identified genome region, showed a single nucleotide mutation of a putative RNA polymerase gene, late expression factor-8 (lef-8). These results indicate that lef-8 is essential for BmNPV replication in vitro and in vivo.

Animals↗
PubMed1998

Homotypic adhesion through carcinoembryonic antigen plays a role in hepatic metastasis development.

We established a cell line with high metastatic potential to the liver (LS-LM4) after four successive repetitions of splenic injection of liver-metastatic cells in SCID mice. This cell line strongly expressed CEA and showed increased homotypic adhesion as compared with the parent cell line (LS174T). To examine the role of CEA in the increased homotypic adhesion, LS-LM4 cells were treated with anti-CEA antibody and subjected to an in vitro adhesion and aggregation assay. Further, to study the role of CEA in the hepatic metastasis of cells with high metastatic potential, LS-LM4 cells were treated with anti-CEA antibody, and the inhibition of hepatic metastasis after splenic injection in vivo was examined. There was a 62% decrease in the homotypic adhesion of anti-CEA antibody-treated (100 microg/ml) LS-LM4 cells under a Ca2+-free condition as compared with the control (P<0.01). Anti-CEA antibody (100 microg/ml) inhibited cell aggregation under a Ca2+-free condition (P<0.05). Treatment with anti-E-cadherin antibody (60 microg/ml) plus anti-CEA antibody (100 microg/ml) inhibited cell aggregation more potently than anti-E-cadherin antibody treatment alone in the presence of Ca2+. In vivo, there was a 75% decrease in the number of hepatic metastatic nodules in the G125 anti-CEA antibody-treated group as compared with the control group (P<0.01). Similarly, there was a 40% decrease in the diameter of metastatic nodules and there was a 90% decrease in total tumor volume of hepatic metastasis in the G125 anti-CEA antibody-treated group as compared with the control (P<0.01). These results suggest that increased metastatic potential to the liver is at least partly due to increased homotypic binding mediated by CEA.

Animals↗
PubMed1998

In vivo spasmolytic effect of ketamine and adrenaline on histamine-induced airway constriction. Direct visualization method with a superfine fibreoptic bronchoscope.

BACKGROUND: Ketamine (K) has been reported to produce bronchodilation in patients suffering from asthma. Although most researchers have used indirect measurements to study the effect of K in vivo, the reliability of these indirect methods are controversial. We have developed a new technique to measure the bronchial cross-sectional area (BCA) in vivo with a superfine fibreoptic bronchoscope (SFB). Employing this method, we evaluated in vivo spasmolytic effect of K and adrenaline (A). METHODS: Twenty-one mongrel dogs were anaesthetized with pentobarbitone (30 mg.kg-1) and paralyzed with pancuronium (200 micrograms.kg-1.h-1). The trachea was intubated with an endotracheal tube that has a second lumen for insertion of a SFB (OD: 2.2 mm) to measure the BCA continuously. The tip of the SFB was placed between the 2nd and 3rd bronchial bifurcation of the right lung. A videoprinter printed the BCA, which was then measured with NIH Image. Bronchoconstriction was produced with histamine (H: 10 micrograms.kg-1 + 500 micrograms.kg-1.h-1) which was administered until the end of the experiment. The BCA was assessed before and 30 min after the start of H infusion. The dogs were randomly allocated to 3 groups of 7 dogs each. In group K, K (0-10 mg.kg-1) was given i.v., and the BCA was measured 5 min after each K dose. In group A, A (0-0.4 microgram.kg-1) was given i.v., and the BCA was measured 1 min after each A dose. In group A + K, K (1 mg.kg-1 i.v. + 1 mg.kg-1.h-1 i.v.) was given followed, 30 min after, by A i.v. in the same doses as in group A. The BCA was assessed 30 min after the start of K and again 1 min after each A dose. RESULTS: K 10 mg.kg-1 reversed H-induced bronchoconstriction. A subthreshold dose of K significantly potentiated the effect of A, reversing the decrease in BCA by H. CONCLUSION: We have found that K could reverse the H-induced bronchoconstriction and potentiate the A-induced bronchial relaxation.

Animals↗
PubMed1998

Effects of isoflurane on oxygenation during one-lung ventilation in pulmonary emphysema patients.

BACKGROUND: Hypoxic pulmonary vasoconstriction has an important role in human one-lung ventilation (OLV) in the lateral decubitus position under general anesthesia. During OLV, inhalational anesthesia may inhibit hypoxic pulmonary vasoconstriction and the decrease in arterial oxygenation. We studied the effect of isoflurane administration on arterial oxygen tension in chronic obstructive pulmonary disease patients. METHODS: Ten patients who had thoracoscopic laser ablation of bullous emphysema were studied. Patients received 2% isoflurane in oxygen from induction until the first 20 min of OLV in the lateral decubitus position, then were switched to 1% isoflurane lasting 20 min and next were switched to 0.5% isoflurane lasting 20 min. After each 20-min inhalation, pulmonary and hemodynamic parameters were measured. The given concentrations for isoflurane were merely vapor meter concentrations. RESULTS: PaO2/FIO2, Qs/Qt respiratory rate peak inspiratory pressure and PaCO2 showed no significant changes at each point of isoflurane. Expiratory tidal volume significantly decreased (P < 0.05) with 0.5% isoflurane compared to that with 2% isoflurane. Cardiac output, mean arterial pressure, mean pulmonary arterial pressure, systemic vascular resistance and pulmonary vascular resistance showed no significant changes at each point of isoflurane. CONCLUSIONS: In patients with pulmonary emphysema, arterial oxygenation is not affected by low isoflurane concentration during OLV in the lateral decubitus position.

Aged↗
PubMed1998

Inhibited hypothalamic histamine metabolism during isoflurane and sevoflurane anesthesia in rats.

BACKGROUND: Histamine is most densely distributed in the hypothalamus and has an important effect on consciousness or wakefulness. It has been little considered whether general anesthetics could exert their effects on hypothalamic histamine metabolism. The present study was conducted to investigate the effects of isoflurane and sevoflurane anesthesia on hypothalamic histamine metabolism. METHODS: Sixty male Wistar rats were divided equally into isoflurane and sevoflurane anesthesia groups. Each group was divided into three equal sub-groups: the control, anesthesia and recovery groups. The rats of the anesthesia and recovery groups were exposed to either 2% isoflurane or 3% sevoflurane for 30 min. The recovery group was kept in air for 30 min after anesthesia. The rats were decapitated to dissect out hypothalamus which was divided into the fore and rear portion. The contents of histamine and 1-methylhistamine, which is a main histamine metabolite, were determined by high-performance liquid chromatography. The obtained data were analyzed by one-way analysis of variance followed by Bonferoni's test. RESULTS: Histamine contents of the anterior and posterior hypothalamus in both isoflurane and sevoflurane groups increased significantly during the anesthesia and 1-methylhistamine contents of the anterior and posterior hypothalamus in sevoflurane group increased remarkably after anesthesia. The increases of histamine contents supposedly reflected inhibited histamine metabolism and the increases of 1-methylhistamine would be caused by acceleration of histamine degradation. CONCLUSIONS: Histamine metabolism was inhibited during both isoflurane and sevoflurane anesthesia and accelerated only in the posterior hypothalamus during the emergence from these anesthetics.

Analysis of Variance↗
PubMed1998

Chemoreceptive epithelioid cells in the chicken aorta. An electron microscopical study.

Aggregations of granulated epithelioid cells exist in the chicken aorta. In the present study, the locational characteristics of the epithelioid cells were investigated via an electron microscopic approach. Epithelioid cells were found mainly in two regions; the tunica interna just below the endothelial cell layers, and the intermediate region of the tunica media. In the former, the epithelioid cells were in contact with endothelial cells and sometimes directly exposed to the aortic lumen. No contact between the epithelioid cells and the nerve endings was observed in this region. On the other hand, in the intermediate region of the tunica media, five or more epithelioid cells were aggregated, and the synaptic structures were occasionally observed. Additionally, the epithelioid cells in this region was observed to closely contact smooth muscle cells. In an experiment using horseradish peroxidase injection, reactions were detected in the intercellular spaces between the epithelioid cells and endothelial cells. These results suggest that the epithelioid cells localized in the subendothelial region receive information from the aortic lumen, whereas their aggregations in the tunica media are controlled by the nervous system.

Animals↗
PubMed1998

Macrophages in the chicken oviduct: morphometrical studies by light and transmission electron microscopy and the possible influence of sex hormones.

Light and electron microscopic techniques were used to study the morphometry and dynamic changes of macrophages in the postnatal and sex hormone-treated chicken oviduct, respectively. Abundant typical macrophages, containing clear vacuoles, well-developed mitochondria, Golgi complexes and lysosomal bodies in their cytoplasms, were observed in the lamina propria of all segments of the postnatal chicken oviduct, occurring more frequently in the vaginal part. When 7-day-old chickens were injected with diethylstilbestrol (DES), and DES plus progesterone, infiltration of a significant number of macrophages in both groups, but not in controls could be seen. The light and electron microscopic structures of the macrophages in both postnatal and sex hormone-treated chicken oviduct were similar. These results show that typical macrophages are present in the chicken oviduct; their frequency of occurrence varies with different oviductal segments, and they are influenced by sex hormones.

Aging↗
PubMed1998

Accidental transmission of HCV and treatment with interferon.

Accidental transmission of contagious pathogens, especially hepatitis C virus (HCV), by needlestick or other means as an occupational hazard for medical staff is of concern. We retrospectively analysed cases of work-related accidental injury with pathogens such as hepatitis B virus (HBV), HCV, syphilis and human immunodeficiency virus (HIV) reported to the centres for disease control at 15 hospitals (total 5776 beds) in the Gunma prefecture, Japan, from December 1990 to August 1993 (24.7 months). There were 416 such cases (16.8 cases/month), with an incidence of 0.2-3.5 accidents per month per hospital. Such accidents occurred in 297 (71.2%) nurses, 98 (23.5%) medical doctors, 13 (3%) laboratory technicians, four (1.0%) hospital maintenance workers, one (0.2%) assistant nurse, one secretary and two others. There were 323 (77.6%) injuries caused by needlestick, 42 (10.1%) from suture needles or surgical knife cuts, 17 (4.1%) from blood splatters from patients into the eyes or mouth, 10 (2.4%) from contact with injured skin and 24 (5.8%) simple skin contacts. Of the pathogens, 60.3% were HCV, 22.6% HBV, 5.8% syphilis, 0.7% HIV and 10.6% were of unknown origin. Four cases (1.6%) of HCV infection were found and treated with one or two courses of interferon therapy, and HCV was subsequently cleared. All four patients were cured with interferon therapy. None of the HBV-injured cases resulted in infection, possibly because of prophylaxis with HB immunoglobulin and HB vaccine. No HIV or syphilis infection was contracted. In summary, chronic HCV infection acquired as an occupational hazard can be cured by appropriate treatment, such as with interferon, after early detection of the infection.

Accidents, Occupational↗
PubMed1998

In-vivo calibration of microdialysis probe by use of endogenous glucose as an internal recovery marker: measurement of skin distribution of tranilast in rats.

To estimate the absolute concentration of substrates surrounding a microdialysis probe in-vivo, we developed a simple calibration method using endogenous glucose as an internal recovery marker and determined the skin distribution of tranilast (N-(3,4-dimethoxy-cinnamoyl)anthranic acid), an anti-allergic agent, in rats. This calibration method was based on the assumption that the concentration of glucose in the extracellular fluid of skin tissues is the same as that in plasma and that the in-vivo recovery ratio of glucose to tranilast by microdialysis is the same as that estimated in-vitro. Based on these assumptions, the dialysate concentrations of tranilast and glucose recovered from cutaneous microdialysis, glucose concentration in plasma, and in-vitro recovery ratio of tranilast to glucose by microdialysis were determined for the estimation of absolute unbound concentration of tranilast in the extracellular fluid of skin tissues. In an in-vitro study employing plasma containing tranilast, the unbound concentration of tranilast in plasma estimated from the dialysate concentration was just comparable with that determined by ultrafiltration methods. Also in an in-vivo study under steady-state plasma concentration of tranilast in rats, the estimated concentration of tranilast in the skin extracellular fluid was the same level as the unbound concentration of tranilast in plasma. Using the present calibration method, the skin distribution of tranilast administered into the intestinal loop or transdermally was continuously monitored in a quantitative manner.

Animals↗
PubMed1998

[Prevention of Lyme borreliosis infection after tick bites].

Lyme borreliosis is one of the zoonotic and vectorial diseases in the world. Female of Taiga tick, Ixodes persulcatus play an important role being the main vector of the agents, Borrelia burgdorferi sensu lato, of the disease in the Far East including Japan. The number of patients who contacted Lyme borreliosis have been estimated to be around 100 cases in all of Japan. We also detected the spirochetes from the skin tissues of 27 cases involving erythema and 3 cases without erythema after tick bites in Hokkaido. We noticed that in those cases when the victims removed ticks by themselves using their fingers within several days later, almost all of them developed erythema. On the other hand, an infected tick from 8 cases which were removed by surgical procedure, the spirochetes were not transmitted in these cases (No. 31-38). Therefore, we supposed that the transmission of agents takes place by regurgitation of the spirochestes from the midgut diverticula due to the pressure by fingers (calling Syringe phenomenon). Then, the authors recommended that fine tweezers has a firm grip around the mouth part of infested tick and pull out within 24 hours and/or trials to surgical operation for tick removal on passing over 24 hours after infestation.

Adolescent↗
PubMed1998

Preventive effect of erythromycin on experimental bleomycin-induced acute lung injury in rats.

BACKGROUND: Erythromycin has been reported to have an inhibitory effect on chronic inflammatory airway disease and chronic infiltration of neutrophils into the airway. Bleomycin (BLM) often induces interstitial lung fibrosis following acute lung injury. A study was undertaken to investigate the effects of erythromycin (EM) on experimental bleomycin-induced acute lung injury in rats. METHODS: Bleomycin-induced lung injury was assessed by light microscopic examination, measurement of neutrophil elastase activity and of the interleukin 8 (IL-8) content in bronchoalveolar lavage (BAL) fluid. The potential inhibitory effect of erythromycin was assessed by overall comparison of erythromycin untreated (BLM alone), concurrently treated (BLM + EM), and pretreated (BLM + pre-EM) groups. RESULTS: The neutrophil count and concentration of neutrophil-derived elastase in BAL fluid were significantly different in the three groups. The morphological changes of lung injury were also less extensive in rats pretreated with erythromycin. However, these protective effects were not marked in the group concurrently treated with erythromycin. Moreover, the concentration of IL-8 in the BAL fluid tended to be less in the erythromycin treated groups; however, there were no significant differences between the bleomycin-treated groups. CONCLUSION: Erythromycin exhibits a prophylactic effect on acute lung injury induced by intratracheal administration of bleomycin, which is possibly associated with a downregulation of neutrophil-derived elastase.

Animals↗
PubMed1998

A case of Lyme disease with parotitis.

A-59-year-old Japanese woman presented a cellulitis-like erythematous skin rash, low-grade fever, and general fatigue, accompanied by a firm swelling of the right parotid gland. She had a history of tick bite on the right lateral neck 2 weeks before. Serum anti-Borrelia burgdorferi antibody was positive by Western blot analysis, and B. burgdorferi was isolated from the skin lesion. Serum amylase level was elevated with predominant salivary gland isozyme; the level returned to normal within 3 weeks following penicillin and tetracycline treatment. Parotitis might be included among the rare complications of Lyme disease affecting the head and neck region.

Borrelia burgdorferi Group↗
PubMed1998

Malignant mesodermal mixed tumor of the ureter.

Malignant mesodermal mixed tumor comprised of epithelial and nonepithelial components is rarely encountered in the urological field. Only 6 cases of malignant mesodermal mixed tumor of the ureter have previously been reported in the literature. We recently encountered a 7th case of malignant mesodermal mixed tumor of the ureter and describe the case in detail. The etiology of malignant mesodermal mixed tumor is also discussed.

Aged↗