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Biomedical subjects

M Ueda

Publications and source records attributed to M Ueda.

At least 451 records · Page 25Linked to original sources
PubMed1997

Dibutyryl cyclic adenosine monophosphate attenuates lung injury caused by cold preservation and ischemia-reperfusion.

OBJECTIVE: Dibutyryl adenosine 3',5'cyclic monophosphate (db-cAMP) is a membrane-permeable analog of adenosine 3',5'cyclic monophosphate (cAMP). We examined the effect of db-cAMP against lung injury caused by cold preservation and ischemia-reperfusion. METHODS: Rats were divided into three groups (each n = 6) according to the presence or absence of db-cAMP in the preservative solution and cold ischemia (4 degrees C for 15 hours). In the fresh group, the lung was flushed with the preservative solution and reperfusion was performed immediately. In the control group and the db-cAMP group, the lung was flushed either with the solution or with a combination of the solution plus db-cAMP, respectively, and preserved at 4 degrees C for 15 hours. The lung was reperfused for 60 minutes in an ex vivo rat lung perfusion model. RESULTS: The shunt ratios of the reperfused lung in the db-cAMP group were 4.0% +/- 1.6% and 3.4% +/- 1.2% 10 and 60 minutes, respectively, after the initiation of reperfusion, being as low as those in the fresh group and significantly lower than those in the control group (p < 0.01). The wet/dry weight ratio of the lung tissue after reperfusion was 5.99 +/- 1.50 in the db-cAMP group, which was similar to that in the fresh group (5.45 +/- 0.23) and significantly lower than that in the control group (14.20 +/- 3.43) (p < 0.01). Electron microscopic examination showed less damage in the pulmonary arterial endothelium in the db-cAMP group. CONCLUSIONS: We conclude that db-cAMP attenuates the lung injury by cold preservation and ischemia-reperfusion, at least partly by protection of the vascular endothelium.

Animals↗
PubMed1997

Renoprotective effects of a combined endothelin type A/type B receptor antagonist in experimental malignant hypertension.

We previously showed that plasma endothelin-1 (ET-1) concentration was increased in deoxycorticosterone acetate (DOCA)-salt-induced malignant hypertension in spontaneously hypertensive rats (SHR). In contrast, in normal SHR, this value is similar to that seen in Wistar-Kyoto (WKY) rats. The purpose of this study was to examine the effects of the new combined ET type A/type B (ETA/B) receptor antagonist, TAK-044, on the development of hypertension in this model of malignant hypertension. TAK-044 10 mg/kg, which effectively blocks both ETA and ETB receptors, was administered intraperitoneally once per day for 4 weeks in DOCA-salt SHR, and the effects on ET-1 and other parameters were compared with the same values in untreated WKY rats, untreated DOCA-salt SHR, and hydralazine-treated DOCA-salt SHR. DOCA-salt caused marked increases in blood pressure, blood urea nitrogen (BUN), serum creatinine, and plasma ET-1 concentrations in SHR. Both TAK-044 and hydralazine significantly suppressed the increase in blood pressure in DOCA-salt SHR to the same extent. Both treatments also suppressed the increase in BUN and serum creatinine, but this attenuation was less marked with hydralazine than with TAK-044. Neither TAK-044 nor hydralazine affected plasma ET-1 concentration in this model. TAK-044 significantly reduced kidney weight in DOCA-salt SHR, whereas the decrease seen with hydralazine was less marked. Prevention of DOCA-salt-induced renal structural injury (mesangial hypercellularity, glomerular sclerotic changes, and tubulointerstitial damage) in this model was clearly greater with TAK-044 treatment than with hydralazine treatment. These results suggest that endogenous ET-1 may, at least in part, contribute to renal functional and structural damage in malignant DOCA-salt SHR. Our results raise the possibility of renoprotective effects of ETA/B receptor blockers in certain forms of malignant hypertension.

Animals↗
PubMed1997

Surgical treatment for primary esophageal cancer developing after pharyngolaryngectomy for head and neck cancer.

BACKGROUND: Primary esophageal cancer developing after hypopharyngeal or laryngeal cancer is increasing in frequency, but operative treatment of such cases is not well established. The proximity of both cancers could produce interactive influence on surgical procedures and risk factors. There have been few reports focusing on surgical strategy for such cases. METHODS: We retrospectively investigated the most recent series of 18 patients who had previously undergone pharyngolaryngectomy for cancer and subsequently underwent esophagectomy for second primary cancer of the esophagus. At esophagectomy special care was taken to preserve the tracheal vascularity and to select adequate procedures for lymph node dissection and bowel reconstruction. RESULTS: Curative resection as confirmed macroscopically was achieved in all cases except one. Lymph node involvement was found in half of the patients. No major postoperative complication was observed except for partial necrosis of the trachea in two cases that were conservatively treated. No patient died during hospitalization. The 3-year survival rate was 64% overall and 55% in cases with lymph node involvement. CONCLUSIONS: Although increased operative risk was expected in esophagectomy after pharyngolaryngectomy, our operative results were acceptable. Most risk factors were controllable by selecting appropriate operation procedures. In patients with technically resectable cancer, esophagectomy with systematic lymph node dissection is recommended as in ordinary esophageal cancer.

Aged↗
PubMed1997

Titanium-inlay--a new root-end filling material.

To obtain better results following periradicular surgery, we have developed a Titanium-Inlay with SuperEBA cement as a sealer as a new root-end filling material. This was combined with an ultrasonic root-end preparation technique. The preliminary results suggest that the surgical method we adopted is simple and the results are predictable. The material and technique are presented in this article.

Biocompatible Materials↗
PubMed1997

The effect of the loss of molar teeth on spatial memory and acetylcholine release from the parietal cortex in aged rats.

It has been demonstrated that a loss of teeth is a troublesome problem among age-related pathological phenomena of the oral cavity, which influences the entire body, due to the impairment of mastication. The present studies investigated the abilities of learning and memory and acetylcholine (ACh) release in the parietal cortex in aged rats without molar teeth (hereafter referred to as 'teethless'). After the molar teeth of rats were extracted, the rats were fed with powdered food for 135 weeks. Although the performance in the radial arm maze was progressively acquired by daily training, an increase in the number of errors and a decrease in the initial correct responses were observed in the teethless aged rats compared to the control aged rats, indicating impaired acquisition of spatial memory in the teethless aged rats. The basal level of extracellular ACh in the parietal cortex was not different between the teethless aged rats and the control aged rats. However, the extracellular ACh level of the teethless aged rats under high-concentration of K+ and atropine sulfate stimulation was significantly low compared to that of the control aged rats. These results suggest that the impairment of spatial memory in the teethless aged rats may be due to the functional deterioration of the cholinergic neuronal system induced by tooth loss and that there is a possibility that the loss of teeth may be one of the risk factors for senile dementia.

Acetylcholine↗
PubMed1997

Effect of repeated cold stress on capsaicin-evoked release of glutamate from rat spinal dorsal horn slices.

We investigated the effect of repeated cold stress (RCS) on the capsaicin-evoked release of glutamate from the primary afferent fibers of the rat, and compared this with the effect of inoculation of complete Freund's adjuvant (adjuvant inoculation). The release of glutamate was measured using a fluorometric on-line continuous monitoring system in which the immobilized glutamate dehydrogenase column was connected to an in vitro superfusion system. In the presence of 0.3 microM tetrodotoxin, the application of 1 microM capsaicin to spinal dorsal horn slices evoked glutamate release (18.6 +/- 1.2 pmol mg(-1) protein, n = 11). In rats subjected to RCS (RCS rats), the release of glutamate evoked by 1 microM capsaicin was markedly increased to 272% (n = 6, P < 0.05) of the value for the control group, although the basal release was not significantly altered (n = 6, P > 0.05). Adjuvant inoculation produced a significant increase in the basal and capsaicin (1 microM) evoked release of glutamate to 141 and 344% (n = 6, P < 0.05) of the value for the control group, respectively. The present results suggest that the facilitated release of glutamate from capsaicin-sensitive primary afferent terminals in the spinal dorsal horn is, at least in part, involved in the hyperalgesia of RCS rats as well as the complete Freund's adjuvant-induced hyperalgesia.

Animals↗
PubMed1997

Prevention of infection in dental procedures.

The efficacy of a newly-developed anti-cross-contamination device in dentistry, the Air Flushing Clean System (AFCS), was tested under experimental and clinical conditions. In the experimental situation, a dental air turbine handpiece with or without AFCS was contaminated with two bacterial strains, Staphylococcus aureus FDA209P and Streptococcus mutants ATCC25175. After contamination with these bacteria, the handpieces were subjected to two disinfecting methods. Residual bacteria inside the handpiece or an air/water line were cultured and counted, and compared with controls. In this experiment, with AFCS but no dental vacuum suction, wiping of the handpiece with 70% ethanol gauze reduced the count of S. aureus by 99%. No bacterial contamination in the air/water line was detected after exchanging with an autoclaved handpiece. With AFCS and dental vacuum suction, bacterial contamination in the air/water line, as well as in the interior of the handpiece, was not detected. These results indicate that AFCS could reduce bacterial contamination within the air turbine handpiece more effectively than the conventional handpiece regardless of whether or not the dental vacuum suction was used.

Adult↗
PubMed1997

Incidence of actinic keratosis of Japanese in Kasai City, Hyogo.

We determined the incidence of actinic keratosis (AK) among Japanese by screening for skin cancer in Kasai City, Hyogo, Japan, between 1993 and 1995. The incidence per 100,000 Japanese residents was 223.6 in 1993 and 171.2 in 1994. The prevalence of AK was 291.2 per 100,000 residents in 1993, 203.7 in 1994, and 86.8 in 1995. The prevalence in people who had more than six seborrheic keratoses on sun-exposed body sites and in people who had experienced severe sunburns with blister formation during childhood were significantly higher. These results indicate that more than six seborrheic keratoses and several episodes of blister formation in childhood may be risk factors for AK in the Japanese.

Adult↗
PubMed1997

Prevalence of actinic keratosis in Japan.

Most of the epidemiological studies on skin cancer that have been conducted to date have addressed the incidence in light-skinned Caucasians. To determine the prevalence rate of skin cancer and actinic keratosis (AK) on sun-exposed body sites of Japanese in Japan, we examined the skin of 4736 people during health examinations. The study was undertaken in Kasai City, Japan, which had a population of 52,837 in 1992, where participants in a regional health examination were seen by dermatologists. The final diagnosis was made histopathologically. Participants were also interviewed by means of a questionnaire. A total of 36 cases of AK and two of basal cell carcinoma were identified, to give a prevalence of 413.4 per 100,000 for AK. The prevalence among outdoor workers was significantly higher than that of indoor workers. Furthermore, when the participants were classified into three Japanese skin types, the prevalence of AK among people of skin Type I, who are sensitive to UV irradiation, was significantly higher than that among people of skin Types II and III, who are less sensitive.

Adult↗
PubMed1997

Biofilm formation of Staphylococcus aureus strains isolated from impetigo and furuncle: role of fibrinogen and fibrin.

The formation of membranous structure (thickness from the plastic tissue-culture coverslip (hematoxylin-eosin) > 1 mm; periodic acid-Schiff-positive) was more prominent with Staphylococcus aureus (S. aureus) strains isolated from impetigo (coagulase types I.V origin) than with S. aureus strains isolated from furuncle (coagulase type IV origin) (P < 0.05) in the plastic tissue-culture coverslip in human plasma after 72 h. Attachment of S. aureus cells to a plastic tissue-culture coverslip was more marked in 0-3% fibrinogen/tryptic soy broth (TSB) than in plasma (P < 0.05). The formation of the membranous structure was observed on the plastic tissue-culture coverslip with 0.3% fibrinogen/human serum but not with 0.3% fibrinogen + 5% glucose/TSB. Electron microscopy revealed abundant fibrin around S. aureus cells at 4 h and Ruthenium red-positive materials increased at 24 and 72 h in plasma. Staphylococcus aureus cell attachment to the plastic tissue-culture coverslip in plasma decreased by addition of levofloxacin (LVFX) at 1/2 minimum inhibitory concentration (MIC) and clarithromycin (CAM) at 1/4 MIC. Polysaccharide production of S. aureus cells on the plastic tissue-culture coverslip in plasma decreased with the addition of CAM at 1/4 MIC. Fibrinogen is closely related to initiation of infection but biofilm formation requires the conversion of fibrinogen to fibrin. Thus, attachment of S. aureus cells to the plastic tissue-culture coverslip, conversion of fibrinogen to fibrin by coagulase-prothrombin complex, and production of abundant glycocalyx by S. aureus cells are at least required for the production of biofilm in staphylococcal skin infection.

Anti-Bacterial Agents↗
PubMed1997

Involvement of prostaglandin E2 in rabbit corneal injury by anterior segment ischaemia.

The involvement of prostaglandins (PGs) in the development of anterior segment ischaemia after occlusion of the bilateral long posterior ciliary arteries was investigated in rabbit eyes. In this experimental ischaemia, the tissue weight and protein content in the peripheral cornea and the protein content in the aqueous humour increased on the first postoperative day. Topically applied cyclooxygenase inhibitor diclofenac (0.1%) reduced corneal inflammation and further suppressed the elevation in the tissue weight and protein content in the peripheral cornea on day 1 after ischaemia, but did not affect the changes in the aqueous humour. Subconjunctivally administered PGE1 and PGE2 induced corneal oedema and increased corneal protein content in diclofenac-treated and ischaemia-induced eyes, but PGD2, PGF2alpha, and the stable PGI2 analogue cicaprost did not evoke any change. In fact, PGE2 content was markedly increased in the aqueous humour on day 1 after ischaemia, and diclofenac suppressed the increase. In addition, CPT-cAMP increased the corneal tissue weight and protein content in organ culture. These observations suggest that PGE2 may play an important role in developing corneal oedema at the initial stage of ischaemic damage, possibly through the cAMP-mediated pathway.

Alprostadil↗
PubMed1997

Clinical results of cultured epithelial cell grafting in the oral and maxillofacial region.

Cultured epithelium has proven to be a good grafting material for skin defects. In our experience two kinds of epithelial cells, skin keratinocytes and mucosal cells, have been used to fabricate cultured epithelial sheets and autografted to the patients. Traumatic scars of the face were treated by cultured epidermal epithelium (CEE). The skin graft in the oral cavity was replaced by mucosa using cultured mucosal epithelium (CME). Also, the CME was applied to the skin defects at the donor sites of split-thickness skin grafts. Postsurgical follow-up showed good results. As a result, CME was useful in improving the biological environment around the abutments of dental implants, and it also promoted the re-epithelialization of skin defects. From our investigations, CEE/CME are promising treatment modalities which can reduce pain and speed up the healing process in burn patients. Therefore, cultured epithelium banks are worth establishing for auto- and allografting of skin/mucosal defects.

Adult↗
PubMed1997

Trifocal distraction osteogenesis for segmental mandibular defect: a technical innovation.

Distraction osteogenesis in the mandible is a promising method, not only for correction of mandibular hypoplasia such as hemifacial microsomia, but also for reconstruction of segmental bone defects in the mandible. The authors report a case in which a mandibular segmental defect, about 60 mm in length, was reconstructed by distraction osteogenesis. The patient was a 45-year-old man who had been treated for an oral floor cancer. After preoperative chemotherapy and irradiation therapy, the mandible had been resected from the second incisor on the right side to the first molar on the left side, and had been reconstructed with a titanium plate and a vascularized rectus-abdominis compound flap. However, an infection developed around the titanium plate and this plate had to be removed. Therefore, trifocal distraction using an original three-dimensional distractor was performed, at the rate of 1 mm per day (0.5 mm in the morning and 0.5 mm in the evening). During the distraction period, the skin flap was pushed out from the bone defect. Although small free bone transplants were needed for complete continuity, the segmental bone defect was almost filled by the regenerated bone with the lengthened gingiva. Radiographic observation showed successful new bone formation in the lengthened area.

Bone Plates↗
PubMed1997

Maxillary advancement by distraction osteogenesis using osseointegrated implants.

The purpose of this study was to establish a new technique for distraction osteogenesis in the maxilla, using an osseointegrated implant and intraoral device. After extraction of the premolar and molar teeth, four titanium implants were installed in the maxillary alveolar bone. Three months later, the distraction device was connected to the abutments, and osteotomy in the medial portion of maxilla between the implants was performed. Distraction was carried out at the rate of 1 mm per day to obtain a 10-mm elongation, Morphological, radiographic and histological examinations showed that successful maxillary advancement was achieved. New bone was primarily formed by intramembranous ossification and partial endochondral ossification. Titanium implants placed for anchorage of the distraction device remained stable during the course of maxillary advancement. This technique can provide significant advancement of the maxilla with better stability. The treatment system can be applied in any kind of maxillary deformities which need to be corrected surgically by classic osteotomy without bone grafting.

Alveolar Process↗
PubMed1997

Surgical treatment of cancer of the thoracic esophagus in association with a major pulmonary operation.

BACKGROUND: Pulmonary complications have been a major cause of mortality after operations for cancer of the thoracic esophagus. Although the risk involved in esophagectomy associated with a major pulmonary operation is expected to be high, it has seldom been evaluated on the basis of clinical experience. STUDY DESIGN: Of 408 patients who underwent esophagectomy, 8 had previously undergone major pulmonary operation (7 for tuberculosis and 1 for pulmonary cancer) and 10 underwent concurrent major pulmonary resection (7 for pulmonary invasion of esophageal cancer, 2 for synchronous pulmonary cancer, 1 for extensive bronchiectasia). All patients underwent systematic lymph node dissection for esophageal cancer, except one patient with mucosal cancer. To prevent postoperative complications, the operative approach and dissection procedures for esophageal cancer were modified according to the associated pulmonary operation and the extent of cancer invasion. All thoracotomies for esophagectomy were performed on the same side as the major pulmonary operation. Additional median sternotomy was performed when necessary. In the most recent 8 patients who underwent major pulmonary resection concurrent with esophagectomy, the bronchial stump was covered with a pedicle flap. RESULTS: Of the 18 patients who underwent pulmonary operation, postoperative complications developed in 13 of the 18 object patients, but none was fatal. The 3-year survival rate was 45%. All deaths were caused by esophageal cancer or another cancer. CONCLUSIONS: Aggressive esophagectomy associated with major pulmonary operation is not contraindicated in patients with fair risk conditions. The operative procedures for esophagectomy should be appropriately modified to minimize the effect of the associated pulmonary operation. Special care should be taken with respect to the approach for mediastinal dissection and closure of the bronchial stump.

Combined Modality Therapy↗
PubMed1997

A comparative study of removal torque of endosseous implants in the fibula, iliac crest and scapula of cadavers: preliminary report.

This study was undertaken to compare removal torque of endosseous implants in the fibula, iliac crest and scapula of cadavers. The fibulae, iliac crests and scapulae were harvested from the right side of 5 formalin-preserved cadavers. Endosseous implants (Brånemark System) were placed at 3 points of each bone. The removal torque of the implant was measured by a torque gauge manometer (Tohnichi 15 BTG-N). After measurement of the removal torque, the bone was cut at each implant site. The thicknesses of cortical and total bone were measured. The mean removal torques were 46.3 N cm in the fibulae, 15.2 N cm in the iliac crests and 21.4 N cm in the scapulae. There was a statistically significant difference in mean removal torque between the three bones. The total bone thicknesses were 11.7 mm in the fibulae, 9.9 mm in the iliac crests and 8.2 mm in the scapulae. The cortical bone thicknesses were 5.0 mm in the fibulae, 1.6 mm in the iliac crests and 1.8 mm in the scapulae. Significant correlation between the removal torque and the cortical bone thickness was found. However there was no significant correlation between the removal torque and the total bone thickness. In conclusion, the implants inserted in the fibulae showed the highest removal torques as compared to the ones inserted in the iliac crests and the scapulae. Moreover the removal torque was related to the thickness of the cortical bone in the implant sites.

Adult↗
PubMed1997

Differential diagnosis of tumours of the minor salivary glands of the palate by computed tomography.

OBJECTIVE: To define the CT criteria for differentiating malignant from benign tumours of the minor salivary glands of the palate and to evaluate their accuracy. PATIENTS AND METHODS: CT findings of 63 patients with histopathologically proven minor salivary gland tumours of the palate (23 malignant, 40 benign) were retrospectively evaluated. RESULTS: Aggressive bone destruction was a specific finding of malignant tumours, but was seen in only 57% (13/23) of this series. Extension into the pterygopalatine fossa was observed in seven malignant and one benign tumour. Calcifications within a tumour were observed in four cases, all of which were malignant. These three CT findings were significantly more frequent in malignant tumours. Using any one of these as the criterion for the malignancy, the sensitivity was 78% (18/23), specificity 98% (39/40) and accuracy 90% (57/63). CONCLUSION: Malignant tumours of the minor salivary glands of the palate are very likely to show any or all of aggressive bone destruction, extension into the pterygopalatine fossa and calcification, whereas benign tumours can almost always be correctly diagnosed by their absence.

Calcinosis↗