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Biomedical subjects

S Murakami

Publications and source records attributed to S Murakami.

989 records · Page 55Linked to original sources
PubMedDate not supplied

Nitric oxide does not contribute to sodium retention and peripheral vasodilation induced by partial portal vein ligation in rats.

The role of nitric oxide (NO) synthesis in the peripheral vasodilation and sodium retention that occurs after partial portal vein ligation (PVL) was investigated. Hemodynamic studies in PVL rats with sodium retention and in sham-operated controls were conducted on the day when PVL rats developed transient and maximal sodium retention. Measurements were obtained before and during two consecutive periods after NO synthesis inhibition with NG-monomethyl-L-arginine (L-NMMA). Under baseline conditions, PVL rats with sodium retention were hypotensive, with equivalent decreases in total peripheral resistance and glomerular filtration rate in comparison to the control group. After L-NMMA, peripheral resistance and arterial pressure increased by similar extent in both groups. As compared with controls, PVL rats with sodium retention remained hypotensive and vasodilated. Furthermore, L-NMMA-induced natriuresis was attenuated in the PVL group. Additionally, serum and urinary levels of nitrate and nitrite did not vary before surgery and at the time of sodium retention. These results suggest that in PVL rats (1) vasodilation is not NO mediated; (2) vasodilation is not a sufficient explanation for sodium retention, and (3) a sodium-retaining factor acting on the renal tubules is responsible for sodium retention.

Animals↗
PubMedDate not supplied

Orientation of stapedial nerve fibers in the facial nerve trunk.

By staining with toluidine blue and vital staining with methylene blue, the topographical orientation of the stapedial nerve fibers in the facial nerve trunk was visualized in adult guinea pigs. The stapedial nerve with its perineural sheath emerges from the facial nerve trunk in the posteromedial aspect of the upper part of the vertical portion. Toward the horizontal portion, the stapedial nerve fibers gradually ramify, lose their investments, and intermingle with other nerve fibers inside the facial nerve trunk. In the labyrinthine portion, the stapedial nerve fibers are distributed diffusely near the surface along the posterior, medial, and anterior margins of the facial nerve trunk. These findings lead to the conclusion that the stapedial nerve fibers of guinea pigs do not form a single funiculus throughout the intratemporal course of the facial nerve.

Animals↗
PubMedDate not supplied

Effects of facial nerve compression on the stapedial nerve.

A series of experiments on guinea pigs was conducted to determine the prognostic dependability of the stapedial reflex measurement in Bell's palsy. Comparison of the threshold of evoked electromyographic response of the stapedius muscle with that of the orbicularis oris muscle revealed that the stapedial nerve had a lower excitability than did the nerve innervating the orbicularis oris muscle. This lower excitability correlates with the histological finding that the stapedial nerve fibers have a smaller average diameter. The results indicate the resistance of the stapedial nerve to injury of the facial nerve. Functional recovery after cramping of the facial nerve tended to occur later in the stapedial nerve than in the nerve innervating the orbicularis oris muscle. The resistance of the stapedial nerve and the longer period required to recover function in this nerve were factors influencing the prognostic ambiguity of this test.

Animals↗
PubMedDate not supplied

A long-term follow-up of five patients with hepatitis delta virus in Japan.

From 1973 to 1989 five patients with hepatitis delta virus having anti-hepatitis delta antibodies continuously in the serum for more than 5 years were identified among 1019 hepatitis B virus carriers who were being followed-up for more than 3 years (mean 8.9 years). Of the five patients with antibodies, three had a history of blood transfusion, in two cases the transfusion was massive, and one patient had been addicted to narcotics given intravenously 35 years before. In the remaining patient, the route of superinfection could not be determined. Hepatitis delta antigen was detected in hepatocyte nuclei of one of the three patients in whom liver biopsies were performed and there was chronic persistent hepatitis detected by an indirect immunoperoxidase technique. During the follow-up, hepatocellular carcinoma developed in one case but the clinical prognosis was favourable in the remaining four cases.

Aged↗
PubMedDate not supplied

Aseptic necrosis of the capitate bone in two gymnasts.

Aseptic necrosis of the capitate bone is a rare disease, except in the scaphoid bone and the lunate bone. This report describes an aseptic necrosis of the bone in two gymnasts. In both cases, the necrosis probably resulted from dorsiflexion compression injury in gymnastics. In an attempt to enable these patients to continue athletics, partial resection and drilling were performed to give successful results.

Adolescent↗
PubMedDate not supplied

Immunohistologic analysis of synovium in infrapatellar fat pad after anterior cruciate ligament injury.

To clarify the natural course of synovitis after anterior cruciate ligament injury, we took synovial tissues at various periods after injury and analyzed them immunohistologically. Twelve patients with isolated anterior cruciate ligament injuries participated in the study. Inflammation intensity was graded semiquantitatively based on the following parameters: synovial lining cell depth, synovial hyperplasia, vascular hyperplasia, lymphocyte infiltration, and the expression of cell adhesion molecules. The expression of fibrogenic cytokines and the degree of fibrosis were also investigated to elucidate the mechanisms of arthrofibrosis. The results demonstrated that synovitis in the infrapatellar fat pad subsides within 3 months after injury with the progression of fibrosis. Fibrogenic cytokines, platelet-derived growth factor and transforming growth factor-beta, were detected at fibrotic sites, suggesting their involvement in arthrofibrosis. An increased incidence of arthrofibrosis recently has been recognized to occur when anterior cruciate ligament reconstruction is performed within several weeks after injury. We speculate that when anterior cruciate ligament reconstruction is performed during the stage of acute synovitis, the operation may further promote the synovitis, accelerating the arthrofibrotic reaction. Waiting to perform the anterior cruciate ligament reconstruction until the synovitis resolves may possibly decrease the motion problems seen postoperatively.

Adipose Tissue↗
PubMedDate not supplied

Quantitative analysis of synovial fibrosis in the infrapatellar fat pad before and after anterior cruciate ligament reconstruction.

We performed quantitative analysis of synovial fibrosis in the infrapatellar fat pad in 26 patients who underwent arthroscopically assisted anterior cruciate ligament reconstructions. Twelve patients underwent reconstruction with patellar tendon autografts, and 14 had reconstructions with semitendinosus and gracilis tendon autografts. Synovial samples were obtained at the time of reconstruction from 10 patients and at second-look arthroscopy from all 26 patients. Sections from quick-frozen samples were stained with either hematoxylin and eosin or Fast green and Sirius red. We used sodium hydroxide in absolute methanol to elute the Fast green and Sirius red stains, and the total collagen content of each section was estimated by measuring the optical density of the eluted solution. The volume of each section was determined on a computer using an imaging program, and collagen content per unit of tissue was calculated. Median collagen content was 15.3 micrograms/mm3 for the preoperative samples, 25.1 micrograms/mm3 for the group with patellar tendon autografts, and 27.1 micrograms/mm3 for the group with hamstring tendons autografts. Analysis of preoperative and postoperative paired samples revealed a significant increase in synovial collagen after anterior cruciate ligament reconstruction. We observed increased fibrosis in patients who had pain on exertion or stiffness in squatting after the reconstructive surgery.

Adipose Tissue↗
PubMedDate not supplied

A methylenetetrahydrofolate reductase polymorphism is associated with expression of p16 in human lung cancer.

Methylenetetrahydrofolate reductase (MTHFR) is a critical enzyme in the folate cycle. Reduced MTHFR activity induces DNA hypomethylation and stability, which may protect the tumor suppressor gene p16INK4. We examined the association between MTHFR polymorphism and expression of p16INK4. The frequency of the MTHFR genotypes were 21 Ala/Ala, 29 Ala/Aal, and 7 Val/Val. Expression of p16INK4 was 26.2 +/- 26.8% in the Val/Val genotype and 11.2 +/- 16.6% in the other genotypes (p=0.46) as examined by immunostaining, and excluding four specimens that were overstained. These results suggest that folate metabolism can affect carcinogenesis through the expression of p16INK4.

Adult↗
PubMedDate not supplied

Tumor size and extension of lymph node metastases in N2 lung cancer.

In all patients with NSCLC, systematic nodal dissection was performed. Since 1981, 218 stage IIIA-N2 cases were resected. We registered 2 operative mortalities. Overall survival was 23% while, in completely resected cases, survival amounted to 30%. For long-term survival, favourable prognostic factors were cN2 T1-2 N2M0, single mediastinal node involvement and a tumor 20 mm or less in maximum size. The 5 yr survival rates of stage IIIA N2 patients was, respectively 48.1% with tumor diameter < 20 mm, 27.7% with diameter between 21-30 mm, 31.2% with diameter between 31-50 mm and, finally, 16.7% with tumors larger than 51 mm. When micrometastases to lymph nodes in p-stage I (stained with H-E) were examined with immunohistochemical staining, 27% (36 patients of 132) showed micrometastases.

Carcinoma, Non-Small-Cell Lung↗
PubMedDate not supplied

Comparison of Salmonella isolation rates in different types of egg-layer hen houses in Chiba, Japan.

This study investigated the differences in Salmonella isolation rates in environmental samples taken from several types of hen houses in Chiba, Japan. In addition, for the detailed epidemiologic survey, environmental samples, hens, and rodents were collected from Salmonella-contaminated windowless houses on three farms. As a result, Salmonella was isolated from four (80%) of five farms with windowless hen houses; Salmonella enteritidis was isolated from a single windowless house. In contrast, only one serotype of Salmonella was isolated from 1 (6.7%) of 15 farms with open hen houses. In the S. enteritidis-contaminated windowless hen house, the isolation rates of S. enteritidis as compared with the other serotypes were 90.9% of environments, 94.1% of hens, and 86.4% of roof rats (Rattus rattus) that resided in the environments. In reference to the phage type (PT) of these isolates, PT1 was detected in environments and roof rats, and PT9 was detected in both these samples and in hens. Thus, the Salmonella isolation rate in hen houses seems to be associated with whether the premises are windowless or open. Moreover, roof rats appear to be the most important vectors in the spread of S. enteritidis in the windowless hen house because the S. enteritidis PTs coincide with each other.

Animal Husbandry↗
PubMedDate not supplied

Delayed visualization of gallbladder with in vivo labeled Tc-99m-red blood cell scintigraphy for gastrointestinal bleeding.

A case of a 78-year-old man with delayed visualization of the gallbladder during in vivo labeling for 99mTc-red blood cell scintigraphy for gastrointestinal bleeding is reported. The patient had several episodes of renal failure, melena, anemia, blood transfusion, and hemodialysis. The mechanism of this unusual phenomenon is not clear; however, excess binding of heme and 99mTc-pertechnetate caused by autohemolysis and oliguria are suggested to be the main factor in this phenomenon.

Aged↗
PubMedDate not supplied

Evaluation of the clamshell incision for bilateral pulmonary metastases.

To treat bilateral pulmonary metastases during a single operation, simultaneous bilateral thoracotomy via median sternotomy is usually employed. With this approach, however, it is sometimes difficult to access lesions located on the dorsal side of the left lower lobe. We have explored the use of clamshell incisions for such difficult cases. From 1990 to 1995, we studied the use of clamshell incisions in 14 patients with bilateral pulmonary metastases. The average duration of surgery was 212 minutes, the average volume of intraoperative blood loss was 477 ml, and the average number of metastatic lesions extirpated was 23. The endotracheal tube could be removed immediately after the operation in 12 patients, while the remaining 2 patients, who underwent an extensive operation, needed 3 and 4 days of intubation. The arterial blood gas analysis on the first postoperative day for the former 12 patients was as follows: the average value of PaCO2 was 44.4 mmHg, and the average value of PaO2 was 140.4 mmHg (FiO2 = 0.4). None of the patients experienced severe pain or respiratory distress that impaired their daily activities due to continuous epidural anesthesia following surgery. The length of time from surgery to discharge was relatively short, averaging 22 days. We have not encountered any sternal override in our patients. Although we cannot ignore the biological behaviour of primary tumors when selecting a surgical approach, the clamshell incision seems to provide a useful means of thoracotomy when treating bilateral pulmonary metastases. We intend to use this approach in future, taking into careful consideration the indication of each individual case.

Adolescent↗