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Biomedical subjects

Y Naito

Publications and source records attributed to Y Naito.

At least 37 records · Page 2Linked to original sources
PubMed2004

Technical note: Vaginal absorption of 1,25(OH)2D3 in cattle.

Although exogenous 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] administered via intravenous, intramuscular, and oral routes has been tested for efficacy in preventing parturient hypocalcemia in dairy cows, there are few reports concerning intravaginal administration. For this study, 1,25(OH)2D3 was administered via the bovine vaginal lumen, and subsequent changes in blood chemistry, including levels of 1,25(OH)2D3 and several minerals, were measured to confirm vaginal absorption. Each of 5 heifers received a single intravaginal dose of 1 microg of 1,25(OH)2D3/kg body weight; a single control heifer received the ethanol carrier alone. In heifers receiving 1,25(OH)2D3, the plasma 1,25(OH)2D3 levels increased markedly from baseline (88.3 +/- 20.3 pg/mL) within 2 h and reached a peak at 6 h after treatment (1967.4 +/- 1139.6 pg/mL). Plasma Ca levels increased from baseline (10.4 +/- 0.4 mg/dL) to a peak of 11.96 +/- 0.7 mg/dL at 24 h. The levels of inorganic phosphate in plasma increased over time from 7.3 +/- 0.5 to 8.1 +/- 0.8 mg/dL by 6 h and were maintained at a plateau level (9.1 +/- 0.7 to 8.6 +/- 0.6 mg/dL) from 24 to 96 h after treatment. Plasma magnesium decreased from a baseline level of 2.1 +/- 0.1 mg/dL to a plateau level of 1.8 +/- 0.1 mg/dL, which was sustained from 24 to 48 h after treatment. The present study provides evidence of the absorption of exogenous 1,25(OH)2D3 from the bovine vaginal wall, as shown by the marked elevation of plasma 1,25(OH)2D3 levels by 2 h after administration, and indicates the possible utility of intravaginal administration of 1,25(OH)2D3 for prophylaxis of hypocalcemia.

Absorption↗
PubMed2004

[Primary cardiac malignant lymphoma diagnosed intraoperatively during aortic valve repair; report of a case].

A 58-year-old male who complained of chest oppression on effort was diagnosed as aortic regurgitation by echocardiography. The cardiac catheterization was showed moderate aortic regurgitation. He was referred to our hospital for aortic valve replacement. We considered preoperatively that the aortic regurgitation is due to infective endocarditis or aortitis syndrome. We have not noticed cardiac tumor at all until aortic valve replacement. Postoperative pathological diagnosis of the tumor was malignant lymphoma. The tumor had a characteristic architecture of a cardiac MICE (mesothelial/monocytic incidental cardiac excrescence). After the operation, additional chemotherapy using doxorubicin and cysplatin was performed. The patient has been doing well for 5 years after operation.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2004

[Ischemic cardiomyopathy treated with overlapping ventriculoplasty].

A 58-year-old man was admitted due to congestive heart failure. Left ventriculography showed end-diastolic volume index (EDVI) of 172 ml/m2 and ejection fraction (EF) of 16%. Coronary angiography showed severe double vessel disease (the left anterior descending artery and the right coronary artery). Echocardiography showed dilated heart [left ventricular end-diastolic diameter (LVDd) of 74 mm] and severe mitral regurgitation due to tethering of the leaflets. The patient underwent our original left ventricular volume reduction operation, termed overlapping ventriculoplasty (OLVP) combined with mitral annuloplasty, papillary muscles plication (PMP) and coronary artery bypass grafting (CABG). The postoperative course was excellent. Postoperatively, the EDVI decreased to 96 ml/m2, the LVDd diminished to 67 mm, and the EF improved to 34%. This case implies the role of left ventricular remodeling procedure of OLVP and PMP in the ischemic cardiomyopathy with ischemic mitral regurgitation.

Cardiac Surgical Procedures↗
PubMed2004

[Ruptured syphilitic ascending aortic aneurysm; report of a case].

Syphilitic cardiovascular disease has become a rarity today. It most commonly affects the ascending aorta and aortic arch. A case is reported of a 50-year-old female with a ruptured syphilitic ascending aortic aneurysm who underwent an emergency operation. The patient was emergently admitted with complaint of severe dyspnea, circulatory shock due to cardiac tamponade was observed in the emergency room. Bentall's procedure was performed. Intraoperative findings showed multi-cystic dilatation of an aortic root. Penetration was existed on right side posterior wall of an aortic root. Postoperative pathological examination of the aneurysmal wall revealed the characteristic finding of syphilitic aortitis. The postoperative course was uneventful and the patient has been doing well at period of 3 years after operation.

Aneurysm, Ruptured↗
PubMed2003

Enhanced activation of the auditory cortex in patients with inner-ear hearing impairment: a magnetoencephalographic study.

OBJECTIVE: Injury of peripheral auditory organ often induces abnormality of loudness sensation such as loudness recruitment. However, objective evaluation of this phenomenon has rarely been performed. To elucidate this abnormal loudness sensation, cortical mechanisms were investigated by recording auditory evoked magnetic fields (AEFs). METHODS: We recorded AEFs in 8 patients suffering from inner-ear hearing impairment with loudness recruitment and in 14 healthy hearing controls using a 122-channel whole-head neuromagnetometer. Tone bursts of 1 kHz were presented monaurally at 4 different intensities (40, 50, 60, 70 dB HL) with a constant interstimulus interval of 1 s. RESULTS: In both groups, the 100 ms response (N100m) increased in amplitude and decreased in latency as a function of stimulus intensity in both hemispheres. Concerning the source strength, increment of dipole moment of N100m was more rapid according to the stimulus intensity in patients compared with that in healthy subjects. Source strength of N100m was enhanced at high stimulus intensity in patients, and its ratio to healthy subjects was 1.08 at 50 dB, 1.69 at 60 dB and 2.04 at 70 dB. CONCLUSIONS: In patients with inner-ear hearing impairment, enhanced activation of the auditory cortex was observed, and may help explain loudness recruitment.

Acoustic Stimulation↗
PubMed2003

The effect of rebamipide on Helicobacter pylori extract-mediated changes of gene expression in gastric epithelial cells.

BACKGROUND: Recent studies have shown that Helicobacter pylori affects intracellular signal transduction in host cells, leading to the activation of transcriptional factors and the induction of pro-inflammatory cytokines. On the other hand, rebamipide, an anti-gastritis and anti-ulcer agent, could scavenge reactive oxygen species and reduce interleukin-8 (IL-8) expression in gastric epithelial cells induced by H. pylori-stimulation through the attenuated activation of nuclear factor-kappaB (NF-kappaB). AIMS: In this study, we investigated the effects of rebamipide on gene expression in H. pylori-stimulated epithelial cells using DNA chip. METHODS: H. pylori water extract (HPE) was prepared from NCTC11637, the type strain of H. pylori. Total RNA was extracted from MKN45 cells, a human gastric cancer cell line, following HPE-stimulation with and without rebamipide for 3 h, and differences in gene expression profiles were observed using GeneChip and Human 6800 probe array. RESULTS: The GeneChip analysis demonstrated that 132 up-regulated genes and 873 down-regulated genes, such as growth factors, chemokines and transcription factors, were detected in MKN45 cells 3 h after stimulation of H. pylori. Among them, several genes, including bFGF, RANTES and MIP-2beta, were previously unknown to be expressed in H. pylori-stimulated human gastric cells. Rebamipide reduced expression of 119 genes encoding cytokines, growth factors and their receptors and transcription factors. CONCLUSIONS: These findings suggest that rebamipide could inhibit inflammatory reactions and tumour progression by modifying H. pylori infection-induced gene expression in gastric epithelial cells.

Alanine↗
PubMed2003

Comparative histology of the laminar bone between young calves and foals.

Laminar bone or primary plexiform tissue, not Haversian bone, shows an alternative concentric pattern of laminar-bone units or plates around the bone marrow periphery of long bones, although the laminar bone is gradually replaced by osteons during the growth period. One laminar-bone unit is constructed with a hypercalcified line in the center, woven bone on both sides of the line, and lamellar bone with laminated appositional lines. Such a laminar bone showing a homogeneous calcification has been reported in young calves and some young large animals, but it has not been reported in foals although a previous report proposed that the bone structure was distinguishable from plexiform tissue. In this study, we compared young calves with foals by backscattered electron imaging mainly of transverse ground sections of mid-diaphysis. Foals had many hypercalcified lines arranged concentrically around the bone marrow periphery, which were similar to those of young calves. However, rows of cylindrical osteon-like structures with Haversian canal-like canals running along the long-bone axis were arranged between the concentric hypercalcified lines. Each Haversian canal-like structure was enclosed with laminated appositional rings of lamellar bone deposited on the woven bone. In the developing period, the bone units containing the concentric hypercalcified lines were basically equal to the laminar-bone units. The osteon-like structures or 'pseudo-osteons' were gradually replaced by 'true osteons' during the growth period. The blood vessels in the Haversian canal-like canals of foals ran along the long-bone axis, whereas the blood vessels in the concentrically prolonged bone cavities of young calves ran transversely to obliquely against the long-bone axis. Thus, the long-bone cortex of foals showing an alternative concentric pattern of a row of the osteon-like structures arranged between the hypercalcified lines will be histologically classified into a variety of laminar bone caused by the different arrangement of blood vessels. Such a laminar bone may have a biomechanical structure against physical stress, especially the modified laminar bone of foals with osteon-like structures, when compared with the typical concentric laminar bone of young calves and also Haversian bone possessing variously calcified numerous osteons caused by bone remodeling.

Animals↗
PubMed2003

[Surgery for distal aortic arch aneurysm with a patent left internal mammary-to-coronary artery graft; report of a case].

We report a case of 62-year-old male who suffered from a distal aortic arch aneurysm developed 5 years after coronary artery bypass grafting (CABG). Preoperative angiography revealed a distal arch aneurysm and a patent left internal mammary artery (LIMA) graft. Graft replacement of the total aortic arch was performed using a 4 branched graft. After the re-median sternotomy, cardiopulmonary bypass was established with ascending aortic perfusion and right atrium (RA) drainage. Myocardial protection was achieved with root cold blood cardioplegia and LIMA continuous cold blood perfusion. Distal anastomosis was performed under selective cerebral perfusion and during deep hypothermic circulatory arrest. Postoperative course was satisfactory and the patient was discharged without complications.

Aorta, Thoracic↗
PubMed2002

Ubiquitin-proteasome inhibitor enhances tumour necrosis factor-alpha-induced apoptosis in rat gastric epithelial cells.

BACKGROUND: Tumour necrosis factor (TNF-alpha) is a candidate factor for involvement in inflammation-mediated gastric mucosal injury. However, the effect of this cytokine on gastric epithelial cells has been poorly investigated. In the present study, we examined whether gastric epithelial cells are resistant to TNF-alpha-induced apoptosis, and whether this resistance is related to ubiquitin-proteasome-associated nuclear factor-kappaB (NF-kappaB) activation. METHODS: The rat gastric mucosal cell line RGM-1 was grown in DMEM/F12 medium supplemented with 10% FCS. Confluent monolayers of cells were pretreated or not for 60 min with PSI, a peptide aldehyde known to specifically inhibit the chymotrypsin-like activity of 26S proteasome. Cells were subsequently stimulated with recombinant rat TNF-alpha and their viability was determined by WST-1 assay. Apoptosis was confirmed by fluorescence microscopy after staining with Hoechst 33342 and propidium iodide, and DNA fragmentation was determined by flow cytometry using an APO-BRDU kit. IkappaB-alpha and the p65 binding subunit of NF-kappaB were detected by Western blots. RESULTS: Twenty-four-hour incubation with TNF-alpha alone or PSI alone did not affect the cell viability of RGM-1 cells. Pretreatment with PSI significantly enhanced the level of apoptosis induced by TNF-alpha. In RGM-1 cells treated with TNF-alpha, cytoplasmic IkappaB-alpha decreased and p65 in nuclear extracts increased markedly 30 min after cytokine stimulation. Pretreatment with PSI at 12.5 micromol/L blocked these TNF-alpha-induced changes. CONCLUSION: PSI enhances TNF-alpha-induced apoptosis through inhibition of NF-kappaB activation in RGM-1 cells.

Animals↗
PubMed2002

Role of elastase and active oxygen species in gastric mucosal injury induced by aspirin administration in Helicobacter pylori-infected Mongolian gerbils.

BACKGROUND: H. pylori infection potentiates aspirin-induced gastric mucosal injury by mechanisms that include accumulation of activated neutrophils. AIM: To determine the role of elastase and active oxygen species (AOS) produced by activated neutrophils in the gastric mucosal injury induced by administration of acidified aspirin to H. pylori-infected Mongolian gerbils. METHODS: H. pylori ATCC43504 culture broth was administered by oral gavage to male Mongolian gerbils at 7 weeks of age. After 4 weeks, acidified aspirin (400 mg/kg) was administered orally, and 3 h later, the total area of gastric erosions, myeloperoxidase (MPO) activity (an index of neutrophil accumulation), thiobarbituric acid-reactive substances (TBARS, an index of lipid peroxidation), and KC/GRO (a chemo-attractive cytokine in rodents) were measured in gastric mucosa. To determine the role of elastase or AOS derived from neutrophils in these circumstances, ONO-5046 (an elastase inhibitor), a combination of superoxide dismutase (SOD) and catalase (scavengers of AOS), and polaprezinc (an anti-ulcer agent with anti-inflammatory effects) were administered before aspirin. RESULTS: ONO-5046 inhibited the increase in gastric erosions and mucosal TBARS induced by administration of aspirin to H. pylori-infected gerbils, but not the increases in MPO activity or KC/GRO contents. A combination of SOD and catalase or polaprezinc significantly reduced gastric erosions, TBARS concentrations, MPO activity and KC/GRO concentration. CONCLUSIONS: These results suggest that neutrophil-derived-elastase and -oxidants play an important role in the gastric mucosal injury induced by administration of aspirin to H. pylori-infected gerbils.

Animals↗
PubMed2002

Helicobacter pylori infection potentiates aspirin induced gastric mucosal injury in Mongolian gerbils.

BACKGROUND: Helicobacter pylori infection and non-steroidal anti-inflammatory drugs are two major causes of gastric ulceration but interactions between H pylori and these drugs in gastric mucosal injury are unclear. AIMS: We studied the influence of experimental H pylori infection on gastric mucosal injury induced by aspirin. SUBJECTS: Male Mongolian gerbils free of specific pathogens were used. METHODS: H pylori ATCC43504 culture broth was administered by oral gavage at seven weeks of age. After three weeks, acidified aspirin (400 mg/kg) was administered orally, and three hours later the total area of gastric erosions, myeloperoxidase (MPO) activity (an index of neutrophil accumulation), thiobarbituric acid reactive substances (TBARS, an index of lipid peroxidation), and KC/GRO (a chemoattractive cytokine in rodents) were measured in gastric mucosa. To determine the role of neutrophils in these circumstances, antigerbil neutrophil rabbit serum (ANS) was administered to some animals 18 hours before aspirin. RESULTS: Aspirin caused more extensive haemorrhagic erosions (33.1 (12.3) mm2) associated with greater MPO activity (1887.7 (598.5) microU/mg protein) and TBARS (0.33 (0.14) nmol/mg protein) and KC/GRO concentrations (28.3 (9.5) pg/mg protein) in infected than in uninfected gerbils (13.7 (2.3); 204.0 (68.9); 0.12 (0.06); 3.1 (0.8), respectively) Pretreatment with ANS inhibited the increases in gastric erosions, MPO activity, and TBARS but not KC/GRO concentration. The reduction in aspirin induced mucosal injury by administration of ANS was much greater in H pylori infected animals (65%) than in uninfected animals (31%). CONCLUSIONS: H pylori infection potentiates aspirin induced gastric mucosal injury by mechanisms that include accumulation of activated neutrophils.

Animals↗
PubMed2002

Buoyancy and maximal diving depth in penguins: do they control inhaling air volume?

Using a newly developed data logger to measure acceleration, we demonstrate that free-ranging king and Adélie penguins only beat their flippers substantially during the first part of descent or when they were presumed to be chasing prey at the bottom of dives. Flipper beating stopped during the latter part of ascent: at 29+/-9 % (mean +/- S.D.) of dive depth (mean dive depth=136.8+/-145.1 m, N=425 dives) in king penguins, and at 52+/-20 % of dive depth (mean dive depth=72.9+/-70.5 m, N=664 dives) in Adélie penguins. Propulsive swim speeds of both species were approximately 2 m s(-1) during dives; however, a marked increase in speed, up to approximately 2.9 m s(-1), sometimes occurred in king penguins during the passive ascending periods. During the prolonged ascending, oblique ascent angle and slowdown near the surface may represent one way to avoid the potential risk of decompression sickness. Biomechanical calculations for data from free-ranging king and Adélie penguins indicate that the air volume of the birds (respiratory system and plumage) can provide enough buoyancy for the passive ascent. When comparing the passive ascents for shallow and deep dives, there is a positive correlation between air volume and the depth of the dive. This suggests that penguins regulate their air volume to optimize the costs and benefits of buoyancy.

Air↗
PubMed2002

[A case of elderly in shock due to ruptured stanford type A acute aortic dissection with cardiac tamponade].

An 87-year-old female in shock was referred to our hospital. Emergency chest computed tomography and echocardiography showed a dissecting aneurysm of the ascending aorta and remarkable epicardial effusion. She was diagnosed as having rupture of Stanford type A acute aortic dissection with cardiac tamponade and an emergency operation was performed. While anesthesia was administered, cardiac arrest occurred and the chest was opened. We managed to establish an extra-corporeal circulation and performed graft replacement of the ascending aorta with GRF glue. The patient followed a satisfactory postoperative course and was discharged from the hospital at the 48th postoperative day. The proper indication for operation and minimally invasive procedure enabled us to operate on the elderly patient.

Aged↗
PubMed2002

[First successful clinical application of tissue engineered blood vessel].

With this tissue engineering (TE) technique, the peripheral pulmonary artery was successfully reconstructed, using the patient's own venous cells in a 4-year-old girl, 2 years after Fontan procedure. A 4-year-old girl was given a diagnosis of single right ventricle, double-outlet right ventricle and pulmonary atresia. She underwent left modified Blalock-Taussig shunt at a month old, pulmonary artery angioplasty at a year and 3 months old, and bidirectional cavopulmonary shunt at 2 years and a month old. She underwent again pulmonary artery angioplasty and Fontan operation at 3 years and 3 months. An angiographical examination 7 months after the operation revealed total occlusion of the right intermediate pulmonary artery. TE technique using autologous cells was indicated. The application of this procedure was approved by the ethical committee in Tokyo Women's Medical University. The patient's parents were thoroughly informed and signed a consent form. Approximately 2 cm of the peripheral vein was explanted under sterile conditions. The tissue was minced, placed in tissue culture dishes and cultured at 37 degrees C, 100% humidity and a 5% CO2 atmosphere for almost a month. The number of cells substantially increased to reach 12 millions for almost a month. The culture medium was changed every 3 days. The polymer tube that served as a scaffold for cells was composed of the copolymer of PCL-PLA (50:50) with reinforcement by woven PGA. The polymer conduit, 10 mm in diameter, 20 mm in length and 1 mm in thickness, was designated to biodegradate within 8 weeks. The number of seeded cells was approximately a million/cm2. The graft transplantation was performed 10 days after seeding cells. The occlusive right intermediate pulmonary artery was reconstructed with the TE vessel graft under extracorporeal circulation with a pump-oxygenator. The patient followed a satisfactory postoperative course. The postoperative angiography demonstrated that the graft was not constricted and dilated but that it preserved good patency. Long-term follow-up are necessary. We plan to continue to use the TE technique using autologous cells in the low pressure system like venous or pulmonary circulation. Because our results even in early experimental phase were valuable and promising, we believe that the TE approach may play an important role in the near future as an another alternative, together with transplantation and artificial organ, especially in the field of cardiovascular surgery that mostly needs replants.

Blood Vessel Prosthesis Implantation↗
PubMed2002

[Extracardiac fontan procedure in adult: report of a case].

We report a case of a 28-year-old female who underwent an extracardiac Fontan procedure. The subject was diagnosed as an atrioventricular septal defect (Rastelli classification: type C), a double outlet right ventricle, pulmonary artery stenosis, a hypoplasty of left ventricle, total anomalous venous return (Darling: Ib + IIb), and atrial flutter. She underwent a Blalock shunt and an aorto-pulmonary shunt at the ages of 3 and 9 years, respectively. Under a total CPB, an extracardiac total cavo-pulmonary connection (TCPC), using a 26 mm Hemashield graft, was completed. The postoperative course was uneventful. The complicated atrial anatomy and atrial arrhythmia indicated TCPC in this adult patient.

Adult↗
PubMed2002

Plasma hepatocyte growth factor levels after open heart surgery for congenital heart disease.

BACKGROUND: Hepatocyte growth factor (HGF) is a polypeptide which acts protectively against endothelial cell dysfunction. A high plasma level of HGF is shown when the endothelium is injured. We measured plasma HGF levels during and after open heart operations for congenital heart disease, to elucidate its involvement with endothelial cell injury. METHODS EXPERIMENTAL DESIGN: prospective study. SETTING: perioperative setting. PATIENTS: 18 children electively operated upon for congenital heart disease using CPB. RESULTS: Plasma HGF levels (ng/ml) before cardiopulmonary bypass (CPB) were 0.36+/-0.07 in 10 children (S-group) who were older and with simpler diseases, and 0.48+/-0.12 in 8 children (C-group) who were younger and with relatively complex diseases. HGF levels significantly increased after CPB, and gradually decreased thereafter. Plasma HGF levels 3 and 6 hours after CPB were significantly greater in the C-group than in the S-group (1.13+/-0.12 vs 1.68+/-0.1 6 3 hours after, and 1.09+/-0.19 vs 2.35+/-0,43 6 hours after; p<0.05 for both). There were significant positive correlations between HGF levels 6 hours after CPB and the duration of the CPB, the aortic crossclamping time, and plasma thrombomodulin levels just after CPB in all patients (p<0.05 for all). CONCLUSIONS: This data suggests that increased HGF levels are associated with endothelial cell injury induced by CPB, and that the increases are much greater in younger patients with complex anomalies.

Biomarkers↗