Biomedical subjects

Hiroshi Yoshimura

Publications and source records attributed to Hiroshi Yoshimura.

At least 37 records · Page 2Linked to original sources

PubMed2004

Age-dependent emergence of a parieto-insular corticocortical signal flow in developing rats.

By using the procedure that we developed for inducing population oscillation, it was previously demonstrated that insular cortex stimulation can evoke insulo-parietal field potential propagation and synchronized population oscillation in the parietal cortex in slices obtained from mature rats (27-35 days old). By using the same procedure, we have now studied the reciprocal parieto-insular projection. Parietal cortex stimulation elicited synchronized population oscillation in the parietal--but not insular--cortex in mature tissues. In the insular cortex, the initial wavelet of the oscillation generated by parietal cortex stimulation propagated, but the entire oscillation did not. A prior induction--but not simultaneous occurrence--of oscillation in the parietal cortex sufficed to have this initial wavelet propagate. In immature tissue (9-10 days old), both the parietal cortex oscillation and the parieto-insular propagation were induced only with low [Mg2+]o. This age dependence is exactly the same as we previously observed for the reciprocal insulo-parietal propagation. Given that the parietal cortex receives somatosensory inputs from the oral cavity and the insular cortex receives primarily chemosensory inputs from the same source, the age-dependent changes in the availability of bidirectional signal traffic between these cortices might contribute to the development of multimodal responsiveness of taste neurons.

2-Amino-5-phosphonovalerate↗

PubMed2004

Cortical spatial aspects of optical intrinsic signals in response to sucrose and NaCl stimuli.

To examine whether cortical taste neurons use spatial codes for discriminating taste information, we investigated the spatial aspects of optical intrinsic signal (OIS) responses in the gustatory insular cortex (GC) elicited by the administration of two essential tastants, sucrose and NaCl, on the tongue. OIS responses to sucrose appeared in the rostral part of the GC, whereas those to NaCl appeared in the central part of the GC. Local anesthetization of the tongue abolished OIS responses, and the administration of distilled water elicited no OIS response. Thus, taste information elicited by sucrose and NaCl from the peripheral sensory organs is segregated in the GC, suggesting that the information from two essential tastants is assembled as spatial codes in the primary cortical taste area through the process of taste quality perception.

Animals↗

PubMed2004

En-bloc esophagectomy for esophageal cancer.

BACKGROUND: The operative approach for esophageal cancer varies from simple palliative resection to extended esophagectomy with 3-field lymph-node dissection or en-bloc esophagectomy (EBE) depending on tumor and patient status and surgical strategy of the surgeon. The merits and demerits of such EBE are yet to be determined. METHODS: A literature review was done regarding EBE for esophageal cancer. RESULTS: Twenty articles describing EBE were reported from experienced institutions during the last 20 years and were selected for this study. The conclusions drawn from those articles showed that EBE would be a safe procedure with acceptable morbidity and low mortality rates when performed by an experienced surgeon. When strict patient selection criteria were maintained, this procedure decreased locoregional recurrence and improved long-term survival rates. CONCLUSIONS: EBE would be the treatment of choice in selected patients presenting with esophageal cancer. Development of meticulous preoperative risk assessment and optimum postoperative care may further improve the acceptability of this procedure with minimum morbidity and acceptable mortality rates.

Adenocarcinoma↗

PubMed2004

The ideal lavage volume for removing bradykinin, interleukin-6, and protein from the temporomandibular joint by arthrocentesis.

PURPOSE: The aim of this study was to investigate the ideal volume of perfusate for arthrocentesis of the temporomandibular joint (TMJ) disorders (TMDs). PATIENTS AND METHODS: We evaluated 17 joints in 17 patients with TMD in this study. Arthrocentesis of the TMJ was done by perfusion of 400 mL of Ringer's solution. The first 5 mL of perfusate was collected, and then a 5-mL sample was collected when the total volume of perfusate outflow approached 50, 100, 200, 300, and 400 mL. The concentrations of bradykinin, interleukin-6, and protein were measured by immunoassay. RESULTS: The concentration of bradykinin, interleukin-6, and protein during arthrocentesis were effectively reduced by more than 200 mL of lavage (P <.05). With a perfusate volume of 300 to 400 mL, the protein and bradykinin were no longer detectable. CONCLUSIONS: Arthrocentesis is effective for washing out bradykinin, interleukin-6, and protein from the TMJ, and the ideal lavage volume of perfusate for arthrocentesis is between 300 and 400 mL.

Adolescent↗

PubMed2004

Relationship of calcitonin gene-related peptide in synovial tissues and temporomandibular joint pain in humans.

OBJECTIVE: To elucidate the expression of calcitonin gene-related peptide (CGRP) in synovial tissue taken from the human temporomandibular joint (TMJ) with internal derangement, and discuss the relationship between CGRP and joint pain. STUDY DESIGN: Using an immunohistochemical technique, 48 joints in 48 patients were examined. As controls, synovial tissue specimens from 7 joints with habitual dislocation without pain were also examined. RESULTS: In all of the internal derangement and control subjects, CGRP-positive cells were observed in the connective tissues around the blood vessels beneath the lining cells. The extent score of CGRP was significantly higher in the internal derangement group than in the control group (P=.033). There was a significant positive correlation between the extent score of CGRP and joint pain (P=.036, r=0.30). CONCLUSIONS: These results suggest that the expression of CGRP is increased in the synovial tissues from patients with internal derangement, and that CGRP seems to play an important role in the mechanism of pain production in patients with symptomatic internal derangement.

Adolescent↗

PubMed2004

Interleukin-6 family of cytokines as biochemical markers of osseous changes in the temporomandibular joint disorders.

The aim of this study was to find out whether there was a correlationship between the concentrations of interleukin-6 (IL-6), IL-11, and IL-17 in synovial fluid and osseous changes in the condyle. The synovial fluid was obtained from 61 patients with temporomandibular joint disorders (TMD) and seven healthy volunteers (controls). The concentrations of IL-6, IL-11, and IL-17 were measured by enzyme-linked immunosorbent assay. IL-6 was detected in 43 of 59 (73%), IL-11 in 23 of 52 (44%) and IL-17 in 14 of 51 (27%) samples of synovial fluid. The concentrations of IL-6 and IL-11 in the joints with osseous changes in the condyle were significantly higher than in the joints without osseous changes (P < 0.05) and also higher than in the joints of the control group (P < 0.05). In addition, there was a correlation of concentrations between IL-6 and IL-11 (P < 0.05). These results suggest that IL-6 and IL-11 may participate in the pathogenesis of TMD and induce osseous changes in the condyle.

Adolescent↗

PubMed2003

Age-dependent emergence of oscillatory signal flow between the primary and secondary visual cortices in rat brain slices.

Developmental changes in dynamics of signal propagation between the primary (Oc1) and secondary visual cortex (Oc2) were investigated by using optical recording methods with voltage-sensitive dyes. Propagating oscillatory optical responses were evoked by our previously reported procedure, and were recorded on stimulation to white matter of Oc1 in rat visual cortex slices. In immature slices, evoked signals spread out from the stimulation site by way of deep layers, but were restricted largely to Oc1. In mature slices, however, evoked signals spread upward from the stimulation site at first, and then spread out along layer II/III, finally to penetrate Oc2. More remarkably, after this initial signal was attenuated, oscillatory responses emerged and spread back from Oc2 to Oc1 by way of layer II/III, suggesting that the origin of backpropagating oscillation is located in Oc2. The initial forward component was dependent on both N-methyl-D-aspartate (NMDA) and non-NMDA receptors, and the subsequent backward components were dependent only on NMDA receptors. These results suggest that the extent of corticocoritcal signal propagation within the visual cortex grows wider horizontally during maturation, so that information interchange may become easier between the Oc1 and Oc2.

2-Amino-5-phosphonovalerate↗

PubMed2003

Age-dependent appearance of an insulo-parietal cortical signal propagation that elicits a synchronized population oscillation in the parietal cortex in rats.

We investigated postnatal development of a functional connectivity from the gustatory insular cortex to the parietal cortex, which is known to contain many more neurons responding to oral somesthetic stimulation than the insular cortex, in slices obtained from 9-35-day-old rats. Field potentials were evoked by stimulation to the insular cortex. In the mature cortex, insular stimulation elicited a solitary field potential in both the insular and parietal cortices and, as the simulation continued, the initial solitary potential came to be followed by a population oscillation of field potential in the parietal cortex, but not in the insular cortex. In the immature cortex, by contrast, insular stimulation failed to evoke both the initial solitary potential and the subsequent population oscillation in the parietal cortex. In the mature cortex, application of neither thapsigargin nor AP5 prevented elicitation of the initial solitary potential in the parietal cortex, but either of them abolished the parietal oscillation. In immature cortex bathed with low Mg(2+) medium, insular stimulation elicited both the initial solitary potential and the subsequent parietal oscillation, which were both prevented by thapsigargin or AP5. Theses results suggest that the insular and parietal cortices are anatomically connected but functionally unlinked at an early postnatal stage, and that a functional linkage, dependent both on NMDA and ryanodine receptors, is formed during the first postnatal month.

2-Amino-5-phosphonovalerate↗

PubMed2003

Extended esophagectomy with 3-field lymph node dissection for esophageal cancer.

OBJECTIVE: To review the surgical outcomes of extended esophagectomy with 3-field lymph node dissection (3FLND) for esophageal cancer. DATA SOURCES: Only articles written in English and written after 1980 were selected from MEDLINE. The following terms were identified: 3FLND, extensive or extended lymph node dissection (lymphadenectomy), radical lymph node dissection, cervical lymph node dissection, and extended or radical esophagectomy in esophageal cancer. STUDY SELECTION: There were no exclusion criteria for published information relevant to the topic. The most representative articles were selected when there were several articles from the same institution. Case reports were excluded. DATA EXTRACTION: Twenty-six articles were finally col-lected from MEDLINE. Eleven articles were also selected from reference lists of the pertinent literature. DATA SYNTHESIS: The collected information was organized. CONCLUSIONS: The conclusions drawn from those articles showed that extended esophagectomy with 3FLND would be a safe procedure in experienced hands, with low morbidity and acceptable mortality rates. When strict patient selection criteria were maintained, this procedure reduced locoregional recurrence and improved long-term survival rates. Although the therapeutic value of 3FLND is unproved in a randomized trial, extended esophagectomy with 3FLND would be the treatment of choice in selected patients.

Esophageal Neoplasms↗

PubMed2003

Does fibrin glue reduce lymph leakage (pleural effusion) after extended esophagectomy? Prospective randomized clinical trial.

Fibrin glue has been shown to be effective in improving postoperative chylothorax following various thoracic procedures and in reducing lymphorrhea after axillary dissection. It is unknown, however, whether fibrin glue is effective in reducing lymph leakage (pleural effusion) after esophagectomy. A series of 43 consecutive patients with thoracic esophageal cancer who underwent extended esophagectomy were prospectively randomized to two groups: group A (n = 21), in whom 3 ml of fibrin glue was applied to the dissected mediastinum; and group B (n = 22), in whom fibrin glue was not applied. The time of drain removal and the volume of the thoracic drainage were compared. All data were expressed as the mean +/- standard deviation. There were no significant differences in the clinicopathologic characteristics between the two groups. None of the patients developed chylothorax or died during their hospital stay. The daily volume from the thoracic drain (457 +/- 273 ml) was significantly (p < 0.05) larger on postoperative day (POD) 1 in group A than in group B (298 +/- 158 ml) and tended to be larger (p < 0.10) on PODs 4 and 6 in group A than in group B. The cumulative drainage volume was significantly (p < 0.05) larger on PODs 4 to 6 and POD 9, and it tended to be larger (p < 0.10) on PODs 1, 3, 7, 8, 10, and 11 in group A than in group B, suggesting that the cumulative drainage volume in group A was consistently larger than that in group B. The cumulative numbers of patients with a drain remaining in place were not significantly different for the two groups (p = 0.4683). Three patients in group A, however, had prolonged insertion (> 20 days) of the chest tube. There were no significant differences in the incidence of postoperative chest-related complications. No patients in group A developed viral infectious disease during the long-term follow-up. Application of fibrin glue to the dissected mediastinum seems to induce postoperative lymph leakage and thus be responsible for prolonged chest tube insertion in some patients. Hence the use of fibrin glue cannot be recommended for reducing lymph leakage after esophagectomy.

Adult↗

PubMed2003

Predictive factors and timing for liver recurrence after curative resection of gastric carcinoma.

BACKGROUND: Advanced and reliable diagnostic methods in order to identify the site of recurrence of gastric cancer in an early stage are needed. METHODS: One hundred twenty patients whose recurrence was confirmed after curative resection for gastric cancer were enrolled in this study. RESULTS: Liver recurrence was evident in 41 patients. Advanced age, tumor invasion into subserosa, intestinal and mixed type of histology, Borrmann type 0 to 2, tumor diameter (<6.5 cm), and tumor marker (carcinoembryonic antigen and alpha-fetoprotein) elevation were related to liver recurrence. By logistic regression analysis, independent risk factors for liver recurrence included Borrmann's classification, histology, and tumor marker elevation. The median time from the primary operation to liver recurrence was shortest in the tumor marker elevation group when compared with other independent predictors. CONCLUSIONS: This information may help to design a better follow-up program and appropriate treatment strategy for gastric cancer patients with liver metastasis.

Adenocarcinoma↗

PubMed2003

Correlation between the arthroscopic diagnosis of synovitis and microvessel density in synovial tissues in patients with internal derangement of the temporomandibular joint.

OBJECTIVE: To elucidate the correlation between the arthroscopic diagnosis of synovitis and microvessel density in synovial tissues in patients with internal derangement of the temporomandibular joint (TMJ). STUDY DESIGN: Forty-three joints in 41 patients with internal derangement were examined and biopsies taken. Microvessel density was evaluated using the immunohistochemical method for CD 34 antibody. Arthroscopically diagnosed synovitis was evaluated according to Murakami's criteria. RESULTS: In patients with internal derangement, arthroscopically diagnosed synovitis scores averaged 5.2+/-2.0, according to Murakami et al. (1991). Small to large blood vessels were observed clearly with CD 34 stain. The mean microvessel density was 22.7+/-15.6 per two high power fields (magnification x200). Synovitis scores correlated significantly with microvessel density (p=0.002, r=0.43). CONCLUSION: Synovitis evaluated using Murakami's scores correlated well with the number of blood vessels in synovial tissues in patients with internal derangement of the TMJ. This demonstrates that synovitis is linked to inflammation-related blood vessel density of the synovial tissues.

Adolescent↗

PubMed2003

Expression of osteoprotegerin in synovial tissue and degradation of articular cartilage: comparison with arthroscopic findings of temporomandibular joint disorders.

OBJECTIVE: The aim of this study was to investigate the correlations among the expression of osteoprotegerin (OPG) in synovial tissue and the degree of synovitis, the degeneration of articular cartilage, and the adhesions in patients with internal derangement and osteoarthritis of the temporomandibular joint (TMJ). Study design The expression of OPG, which was detected immunohistochemically, and the degree of arthroscopy of 31 patients with internal derangement and osteoarthritis of the TMJ were assessed and the correlations between them were analyzed statistically. RESULTS: OPG was expressed in the cytoplasm of the endothelial cells, synovial lining cells, and fibroblast cells. TMJs with osteoarthritis had a higher degree of articular cartilage degeneration than did TMJs with internal derangement. There was a correlation between the expression of OPG in the endothelial cells and the degree of the articular cartilage degeneration (P <.01). CONCLUSION: The expression of OPG might be associated with the development of degenerative changes of articular cartilage.

Adolescent↗

PubMed2003

Does joint effusion on T2 magnetic resonance images reflect synovitis? Part 3. Comparison of histologic findings of arthroscopically obtained synovium in internal derangements of the temporomandibular joint.

OBJECTIVES: To evaluate the relationship between the volume of joint effusion (JE), determined by T2-weighted magnetic resonance imaging (MRI), and microscopic findings of synovial inflammation in internal derangement of the temporomandibular joint (TMJ). STUDY DESIGN: Magnetic resonance images of 53 symptomatic TMJs (53 patients) associated with painful hypomobility were taken to evaluate the degree of JE on a scale of 0 to 3. Within 2 months after MRI, biopsy specimens obtained by arthroscopy were quantitatively assessed, on the basis of Gynther's grading system, for severity of hyperplasia of synovial lining cell layers, vascularity, and the presence of inflammatory cells. Each synovitis score was compared among the 4 JE grades, as well as between 2 groups-effusion present (grades 2 and 3) and effusion absent (grades 0 and 1)-by using the Spearman correlation coefficiency and the Mann-Whitney U test. RESULTS: The distribution of JE was as follows: 14 joints had grade 0, 9 joints had grade 1, 19 joints had grade 2, and 11 joints had grade 3. Significant relationships were found between the grades of JE and scores of synovial lining cell layers (P =.0012) as well as between the grades of JE and scores of presence of inflammatory cells (P =.0064). The joints with effusion had significantly higher scores for synovial lining cell layers (2.0 +/- 0.2) than the joints without effusion (1.3 +/- 0.2) (P =.029). There was no statistically significant correlation between the scores of vascularity and JE (P =.394). CONCLUSIONS: The evidence of JE on MRI might correlate with synovial inflammatory activity. It confirms the common consensus that JE probably reflects synovitis, especially when synovial hyperplasia has a key role in the pathogenesis of JE.

Adolescent↗

PubMed2003

Acute cholecystitis and cholelithiasis developed after esophagectomy.

BACKGROUND: Although the prevalence of gallstone disease after gastrectomy is reported to be high, its prevalence after esophagectomy is scarcely reported. MATERIALS AND METHODS: Gallbladder disease following an esophagectomy was prospectively evaluated in 237 patients with esophageal cancer by abdominal ultrasonography twice a year up to five years postoperatively. The median follow-up period was 18.6 months. RESULTS: One patient (0.4%) developed acute acalculous cholecystitis postoperatively, and 13 patients (5.5%) developed gallstone disease during the follow-up period. Nine (69%) of these 13 patients developed gallstone disease within two years, and another two patients developed the disease three years after esophagectomy. Another patient developed gallbladder debris at 35 months postoperatively, and one developed gallbladder polyps at 33 months. Seven of the 13 patients with gallstone disease underwent cholecystectomy between 13 and 125 months after esophagectomy: two developed acute cholecystitis; two had associated common bile duct stones; the remaining three patients had upper abdominal pain. Nine of the 13 patients who developed gallstone disease showed a history of alcoholism, whereas only 81 of 224 patients without gallstone disease had a similar history (P<0.05). CONCLUSION: A certain number of patients with esophageal carcinoma and a history of alcoholism develop cholelithiasis within three years after esophagectomy, and subsequently undergo cholecystectomy during the follow-up period.

Acute Disease↗

PubMed2002

Age-dependent occurrence of synchronized population oscillation suggestive of a developing functional coupling between NMDA and ryanodine receptors in the neocortex.

Synchronized population oscillation of delta to alpha range frequencies was synaptically induced in rat visual cortex neurons, depending on (1) the extent of N-methyl-D-aspartate (NMDA) receptor activation, (2) occurrence of calcium-induced calcium release (CICR), and (3) the age of animals. In adult slices bathed with 0.1 mM Mg(2+), as white matter stimulation continued, solitary synaptic potentials gradually became enlarged and overridden by small wavelets oscillating at alpha range frequencies. The calcium store depeletor thapsigargin prevented appearance of these wavelets. When Mg(2+) block of NMDA receptors was intensified with 0.5 or 2.0 mM Mg(2+), the oscillation failed to be induced, but became inducible by caffeine, which facilitates CICR. NMDA receptor blockade abolished induction of the oscillation even under caffeine application. In immature slices, the induction of oscillation was possible only with 0.1 mM Mg(2+) and bath-applied caffeine, but failed with 0.5 mM Mg(2+) or without caffeine. The oscillation induced in immature tissue was smaller in amplitude and frequency (delta-theta; range) than in adult tissue (alpha range). Immature tissue thus requires more restricted conditions for inducing the oscillation. We propose that NMDA and ryanodine receptors become coupled during maturation to enhance synaptically induced intracellular calcium releases, thereby facilitating induction of the oscillation at later stages.

Age Factors↗

PubMed2002

Esophageal cancer patients surviving 6 years after esophagectomy.

BACKGROUND: Esophageal cancer is one of the most malignant tumors, with a dismal prognosis in spite of recent advances in early diagnosis and extended lymphadenectomy. These patients need to be stratified according to prognostic variables for precise identification of high-risk group. MATERIAL AND METHODS: Seventy-six patients with esophageal carcinoma were uniformly treated with curative intent between 1980 and 1992 with at least 6 years follow-up. Results and prognostic factors of long-term survival were analyzed by univariate and multivariate analyses. RESULTS: Thirty patients (39.5%) survived 6 years, and the remaining 46 patients died within 6 years: recurrent esophageal cancer in 27 and causes unrelated to esophageal cancer in 19. The 1-, 2-, 3-, and 6-year overall survival rates in all 76 patients were 77.6%, 57.9%, 53.9%, and 39.5%, respectively. The factors influencing survival rate verified by univariate analysis were Borrmann classification (0, 1 vs. 2, 3), size of tumor (< or =3.0 vs. >3.0 cm), depth of invasion (T1, 2 vs. T3, 4), pN category (pN0 vs. pN1), number of lymph node metastasis (< or =4vs. >4), metastatic lymph node ratio (< or =0.1 vs. >0.1), time of operation (< or =480 vs. >480 min), and amount of perioperative blood transfusion given (< or =2 vs. >2 U). Among the significant variables independent prognostic factors for survival determined by multivariate analysis were metastatic lymph node ratio and amount of blood transfusion. CONCLUSIONS: A significant number of patients can thus apparently be cured of esophageal carcinoma by extensive resection. Patients with many metastatic lymph nodes and much blood transfusion, on the other hand, should receive appropriate treatment against such esophageal carcinoma.

Aged↗

PubMed2002

Expression and prognostic significance of PTEN product protein in patients with esophageal squamous cell carcinoma.

BACKGROUND: PTEN is a candidate tumor-suppressor gene in a variety of malignant tumors. The prognostic importance of PTEN product protein (PTEN) and its correlation with clinicopathologic characteristics have yet to be delineated in patients with esophageal carcinoma. METHODS: Specimens from 97 patients with esophageal squamous cell carcinoma were used for the immunohistochemical evaluation of PTEN expression. RESULTS: PTEN expression was detected in the nucleus in 48 specimens (49.5%). There were statistically significant correlations between nuclear PTEN expression and macroscopic tumor classification, T stage, and American Joint Committee on Cancer (AJCC) stage (P < 0.01), indicating that PTEN expression was down-regulated by advancement of the disease process. There were no statistically significant correlations between nuclear PTEN expression and the intensity and extent of cytoplasmic PTEN expression. The 10-year overall survival rate was significantly better in patients with positive nuclear PTEN expression (n = 48 patients) compared with the rate in patients with negative nuclear PTEN expression (n = 49 patients; P < 0.01). The results of a multivariate analysis of factors that were prognostic for survival showed that AJCC stage (P < 0.05; relative risk, 2.038) and negative nuclear PTEN expression (P < 0.05; relative risk, 1.825) were significant factors indicative of poor survival. CONCLUSIONS: Nuclear PTEN expression may be a favorable biologic marker and a useful prognostic indicator in patients with esophageal squamous cell carcinoma.

Aged↗