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Biomedical subjects

H Suda

Publications and source records attributed to H Suda.

At least 55 records · Page 3Linked to original sources
PubMed2001

Isolated unilateral absence of a pulmonary artery: influence of systemic circulation on alveolar capillary vessels.

We report a case of isolated unilateral absence of a pulmonary artery. The first clinical symptom that was manifested in the patient was recurrent hemoptysis, and subsequent angiography revealed that the main pulmonary artery was absent in the right lung, which was being fed only from the systemic circulation. Right pneumonectomy was performed, and neither the main pulmonary artery nor its remnant was detected in the resected right lung. Histologically, there were many muscular vessels in the resected lung, with intimal proliferation, or with plexiform-like lesions. The alveolar septum was moderately thickened and alveolar capillary vessels were dilated. We examined the alveolar capillary endothelial cells of the resected lung for immunoreactivity to thrombomodulin (TM) and von Willebrand factor (vWF). The endothelial cells were negative for TM and positive for vWF, while in the normal lung control group, these cells were positive for TM and negative for vWF. We considered that the hemodynamics of the systemic circulation in the resected lung caused the alteration of immunohistochemical characteristics in alveolar capillary endothelial cells.

Adult↗
PubMed2001

Ultrastructural analysis of MHC class II molecule-expressing cells in experimentally induced periapical lesions in the rat.

Periapical lesions were induced by making 28 days of unsealed pulp exposures in the lower first molars of Wistar rats. Major histocompatibility complex class II molecule-expressing cells were then demonstrated by means of immunoperoxidase staining using a monoclonal antibody OX6, and the ultrastructure of these cells was analyzed under electron microscopy. OX6+ cells were classified into two major populations, (i.e. macrophages and dendritic cell (DC)-like cells. DC-like cells had elongated cytoplasmic processes, contained a few lysosomal structures, lacked distinct phagosomes, and were the most predominant cell type in the established lesion. Some of lymphocytes and plasma cells also showed a positive immunoreactivity. Both OX6+ macrophages and DC-like cells often showed a cell-to-cell attachment with lymphocytes. These findings suggested that major histocompatibility complex class 11 molecule-expressing macrophages and DC-like cells may play a crucial role in periapical lesion development by acting as antigen-presenting cells to memory T lymphocytes.

Animals↗
PubMed2001

Non-involvement of the K-ras mutation in colon carcinogenesis promoted by dietary deoxycholate in azoxymethane-treated rats.

Fisher-344 rats, whose ileum or jejunum had been surgically removed to change the influx of bile acids into the colon, were intraperitoneally administered with azoxymethane and fed on a diet containing deoxycholate for 39 weeks to induce colon cancer. Fecal bile acids in the ileum-resected group were 1.5-times and serum bile acids were about half of those in the jejunum-resected group. As a result, the incidence and number of tumors were higher in the ileum-resected group. In the total of 59 colon tumors (40 were in the ileum-resected group and 19 in the jejunum-resected group), 56 were carcinomas, including two well-differentiated invasive and two mucinous carcinomas found in the ileum-resected rats. However, only three carcinomas, two invasive and one non-invasive, had the K-ras mutation. These results demonstrate that the K-ras mutation was not essentially involved in deoxycholate-promoted colon carcinogenesis.

Animals↗
PubMed2001

Effect of NaClO treatment on bonding to root canal dentin using a new evaluation method.

The purposes of this study were to investigate the reliability and efficiency of a new evaluation method for resin bonding to root canal dentin, which measures both marginal adaptation and shear bond strength simultaneously, and to determine the effects of root canal irrigants on resin bonding. A wet bonding system (Single Bond) and a self-etching primer system (Clearfil Mega Bond) were employed; NaClO was used as a root canal irrigant. No gaps or changes in bond strength were observed despite the NaClO treatment when the wet bonding system was employed, while the gap formation ratio increased, and bond strength decreased with longer NaClO treatment time when the self-etching primer system was employed. These findings suggested that this new experimental method was effective for evaluating resin systems to the root canal wall dentin which is affected by irrigation with NaClO.

Animals↗
PubMed2001

[Early operation for acute type a closing dissection].

From March 1997 to January 2000, we operated eleven cases of Stanford type A acute closing dissection. The patients consisted of 4 men and 7 women with a mean age of 71 +/- 9 years. There were 9 cases (81%) of cardiac tamponade and 5 cases (45%) was in the shock state. There were no malperfusion and end organ ischemia. All cases were operated with deep hypothermia and circulatory arrest. Ascending aortic replacement were performed in 9 cases and 2 cases were performed total arch replacement. 6 cases (63%) were not required blood transfusion. There was one operative death and one hospital death. These result suggest that we had better to perform immediate graft replacement for Stanford type A acute closing dissection as soon as possible, even if there were no serious complications.

Acute Disease↗
PubMed2001

[A case of minimal invasive aortic valve replacement for quadricuspid aortic valve with aortic regurgitation].

Congenital quadricuspid aortic valve is rare, which may be a cause of sever aortic regurgitation. We report a case of a 55-year-old man who had severe aortic regurgitation with congenital quadricuspid aortic valve. Preoperative aortography showed severe aortic regurgitation. Preoperative trans-esophageal echocardiography revealed abnormal quadricuspid aortic valve. We performed minimal invasive aortic valve replacement with SJM # 21 mm HP prosthetic valve through the limited upper sternotomy. Skin incision was 9 cm. Aortic cross-clamping time was 92 min, cardiopulmonary bypass time was 108 min. At the operation, a quadricuspid valve with three equal cusps and one small cusp was noted. The postoperative course was excellent and he discharged 8 days after the operation.

Aortic Valve↗
PubMed2001

[A case of emergency surgery for acute mitral regurgitation due to complete papillary muscle rupture as a severe form of reperfusion injury: report of a case].

Complete rupture of a papillary muscle following acute myocardial infarction is a severe complication associate with acute left ventricular failure and pulmonary edema. Since the introduction of acute percutaneous transluminal coronary angioplasty (PTCA) in the management of acute myocardial infarction, the frequency of this complication has further decreased. We described a patient who had acute mitral regurgitation due to complete rupture of papillary muscle rupture after successful coronary intervention. Transesophageal echocardiography demonstrated severe mitral regurgitation and the ruptured papillary muscle. At operation, posteriol papillary muscle was found to be totally ruptured. Mitral valve replacement was performed. Postoperative course was uneventful, with 2 days of IABP and 5 days of ventilator support.

Acute Disease↗
PubMed2000

Pulsed Nd:YAG laser irradiation of the tooth pulp in the cat: I. Effect of spot lasing.

BACKGROUND AND OBJECTIVE: The purpose of the present study was to evaluate physiologically pulpal nerve responses and to elucidate histopathologically the pulp tissue reactions to "spot irradiation" with a pulsed Nd:YAG laser. STUDY DESIGN/MATERIALS AND METHODS: Antidromic compound action potentials and the pulpal blood flow (PBF) were recorded from the canine tooth of a sodium pentobarbitone-anesthetized cat. The laser irradiation-induced pulp tissue changes were histologically investigated. RESULTS: The coronal antidromic compound action potentials disappeared in all the teeth tested during lasing, and the time needed to erase them was significantly shortened with increases in lasing power (P < 0.05). The radicular PBF increased when spot irradiation was performed, and the coronal PBF also temporarily increased with low-powered lasing. Histologic investigation revealed that spot irradiation with the laser produced severe damage in the pulp tissue in a dose-dependent manner. CONCLUSION: The present study suggests that spot irradiation with a pulsed Nd:YAG laser risks producing nerve injury and irreversible tissue damage in the pulp with lasing for the purpose of desensitizing hypersensitive dentin.

Action Potentials↗
PubMed2000

Pulsed Nd:YAG laser irradiation of the tooth pulp in the cat: II. Effect of scanning lasing.

BACKGROUND AND OBJECTIVE: The purpose of the present study was to assess whether "scan irradiation" with a pulsed Nd:YAG laser could produce changes in intrapulpal nerve activities and pulpal blood flow and to investigate whether it would cause tissue damage in the pulp. STUDY DESIGN/MATERIALS AND METHODS: The pulsed Nd:YAG laser was used to irradiate, in a scanning manner, the canine tooth pulp in sodium pentobarbitone anesthetized cats. The compound action potentials and spike response in the functional single afferent nerve fibers were recorded while responding to various external stimuli applied to the exposed dentin. Histologic observation was performed to detect lasing-induced tissue changes. RESULTS: Pulpal compound action potentials evoked by various external stimuli were significantly reduced (P < 0.05) and unit firings were observed in both functional single A delta- and C-fibers during irradiation. Unit responses to external mechanical stimulation of the dentin completely disappeared after "scan irradiation" with the pulsed Nd:YAG laser. Histologic observation revealed that irradiation with the laser produced tissue damage in the pulp. CONCLUSION: "Scan irradiation" with the pulsed Nd:YAG laser of cat's teeth produced alterations in the intrapulpal nerve activities, as well as caused tissue damage in the pulp.

Animals↗
PubMed2000

Response of feline intradental nerve fibers to tooth cutting by Er:YAG laser.

BACKGROUND AND OBJECTIVE: The aim of this study was to investigate the response of intradental A- and C-fibers during tooth cutting by Er:YAG laser. STUDY DESIGN/MATERIALS AND METHODS: Bipolar electrical stimulation was applied to the cat's canine to identify functional single nerve fibers of the inferior alveolar nerve. The tip of the canine tooth was cut in 0.5-mm steps until the pulp was exposed. Teeth were alternately cut by using Er:YAG laser (50 mJ, 5 pps) and micromotor under water cooling. The nerve response recorded from the single nerve fibers during laser cutting was compared with that during micromotor cutting. RESULTS: All 26 A-fibers responded to laser cutting with high frequency of nerve firings. The nerve firing rate was significantly higher during laser cutting compared with that during micromotor cutting of superficial dentin (Chi(2) test, P < 0.05) but was not significantly different at deep dentin (P > or = 0. 05). Nine of 11 C-fibers responded to laser cutting when the deep dentin was cut. Among those nine nerve fibers, three also showed a low frequency response to laser cutting of the superficial dentin. CONCLUSION: During the tooth cutting, Er:YAG laser was more effective in activating intradental A-fibers compared with micromotor and also caused the activation of intradental C-fibers.

Animals↗
PubMed2000

Cloning and sequence analysis of the Candida boidinii ADE2 gene.

Candida boidinii ADE2 gene (phosphoribosyl-5-aminoimidazole carboxylase; AIRC, EC 4. 1. 1. 21) has been cloned by homology to the Saccharomyces cerevisiae ADE2 gene. The cloned C. boidinii ADE2 gene complemented the ade2 mutation of S. cerevisiae. Sequence analysis showed a single open reading frame of 1719 nucleotides coding for a polypeptide of 573 residues. Comparison of the deduced amino acid sequence with those of AIRC enzymes from other yeasts showed marked homology among yeast AIRCs.

Amino Acid Sequence↗
PubMed2000

Increased blood flow and nerve firing in the cat canine tooth in response to stimulation of the second premolar pulp.

Mustard oil or mechanical stimulation was applied to maxillary second premolar tooth pulps and pulpal blood flow and or intradental nerve activity in the ipsilateral canine tooth were recorded in the cat. Mustard oil application to the second premolar pulp significantly increased blood flow in the canine tooth pulp to 162.0+/-65.8% (n = 16) of the prestimulation flow compared to control data obtained with application of mineral oil (107.0+/-5.1%, n = 6) (Mann-Whitney U-test, p = 0.0009). Sectioning of the infraorbital nerve and its branches on the experimental side (n = 4) did not affect this increase in pulpal blood flow. The paraperiosteal injection of 2% lidocaine (1.0 ml) without vasoconstrictor significantly inhibited the increase in canine pulpal blood flow induced by mustard oil application to the second premolar pulp (109.8+/-6.8% of the prestimulation level, n = 7) (Mann-Whitney U-test, p = 0.0013). Sporadic firing or sometimes bursts of action potentials in the canine pulp nerves were recorded during and/or after the mustard oil application to the second premolar pulp in three of 16 cases. Four single pulp nerve units firing in synchrony with the mechanical stimulation of the second premolar pulp were recorded in two of eight canines, which substantiated the existence of branched afferents innervating both teeth. These findings suggest that stimulation of the second premolar pulp may induce axon reflex-related vasodilation and intradental nerve firing in the canine pulp via branched afferent fibres innervating both the second premolar and canine teeth.

Animals↗
PubMed2000

Successful valve-sparing in aortic root reconstruction under endoscopic guidance.

OBJECTIVE: Aortic insufficiency (AI) associated with ascending aneurysm can be corrected by valve-sparing aortic root reconstruction ('David' reimplantation, 'Yacoub' remodeling). Intraoperative endoscopic evaluation in the aortic root may help to clarify the procedure and to access competence of the preserved valve. METHODS: Following cross-clamping of the ascending aorta, an endoscopy was inserted into the proximal aortic root. Perfusion of crystalloid cardioplegia enabled the visualization of the pressure-loaded valve in the closed position. Conventional macroscopic evaluation would have overlooked valve prolapse because of a release from perfusion pressure. Valve coaptation was imaged directly before and after the valve-sparing procedure. A total of 17 patients underwent aortic root reconstruction under endoscopic guidance. Indications of the valve-sparing were determined with endoscopic findings. The degree of AI before and after the surgery was evaluated by aortography and scored (0, none; 1 trivial; 2, mild; 3, moderate; 4, severe). RESULTS: Remodeling was employed to eight patients and reimplantation to four. The other five patients were replaced with prosthetic valved-conduit. There was no early and late mortality. Before and after the valve-sparing surgery, grades of AI were significantly reduced. Three patients who underwent reimplantation procedure required late valve replacement for late progression of AI, however, none of the patients with remodeling required reoperation. CONCLUSION: Introduction of an endoscopy successfully reduced postoperative AI and clarified indications and limitations of valve-sparing aortic root operations.

Aortic Dissection↗
PubMed2000

Educating overseas students: just another responsibility or a chance to grow for faculty?

With a gradual decrease of the university-entering young population, Japanese universities face more and more competition for survival. It is up to each university's efforts to be distinctive and competitive to flourish toward the 21st century. At Tokyo Medical and Dental University, the Faculty of Medicine and the Faculty of Dentistry will be reorganised in April 2000 as a graduate-school-centred university, where faculty will face increased demands in research activities while maintaining or even improving undergraduate education. On the other hand, our university has a 20-year history of accepting overseas students mainly from Asia, and ranks first among Japanese national universities in terms of the number of overseas students studying health sciences. Do our faculty regard teaching overseas students as just another responsibility to be fulfilled or as a unique opportunity to grow as a university faculty? In October 1998, a questionnaire was conducted to discover the faculty attitude towards education of overseas students. Out of 211 dental faculty members, 164 responded to the questionnaire. The results indicated that about 90% of the respondents were interested in teaching overseas students and that those who had already served as a supervisor or a tutor found the experience very meaningful. The results also indicated that they encountered problems deriving from language and culture. It was suggested that our university should redefine overseas student education as an important part of our mission by establishing a more comprehensive system for accepting and teaching overseas students.

Attitude of Health Personnel↗
PubMed2000

Response of Class II molecule-expressing cells and macrophages to cavity preparation and restoration with 4-META/MMA-TBB resin.

AIM: The aim was to test the hypothesis that the resin and bonding agent 4-META/MMA-TBB (4-META), has the potential to prevent transdentinal antigenic challenges. METHODOLOGY: Class I cavity preparation and immediate restoration with 4-META were made in the maxillary right first molars of 36 six-week-old Wistar rats. Contralateral teeth with an unrestored cavity served as positive control (cavity without 4-META) group. The maxillary first molars of 12 age-matched normal rats (total 24 teeth) were also examined as negative control (intact tooth group). At 3 or 28 days after cavity preparation, the teeth were subjected to immunoperoxidase staining using OX6 (anticlass II molecules) and ED1 (antimacrophages) as primary antibodies. RESULTS: A total of 10 teeth were not available for histological examination. In the teeth filled with 4-META at 3 days, the density of OX6+ and ED1+ cells in the coronal pulp was significantly higher than that in the intact tooth group. At 28 days, formation of sound reparative dentine was noted and the density of the immunocompetent cells was comparable to the intact teeth. In the teeth without 4-META at 3 days, pulpal abscess was observed in 14 out of 16 and the density of OX6+ and ED1+ cells was significantly increased (P < 0.001, paired t-test) compared with the 4-META group. Partial pulp necrosis had developed in the teeth without 4-META at 28 days. CONCLUSIONS: Restoration with 4-META significantly reduced transdentinal antigenic challenges. This property may have special implications for 4-META's capacity to protect the dentine/pulp complex.

Abscess↗