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Biomedical subjects

S Yamada

Publications and source records attributed to S Yamada.

At least 901 records · Page 50Linked to original sources
PubMed1994

Immune response and in vivo distribution of the virus in chickens inoculated with the cell-associated vaccine of attenuated infectious laryngotracheitis (ILT) virus.

Chickens inoculated with the cell-associated (CA) vaccine acquired higher protective immunity to ILT. In chickens vaccinated with CA or cell-free (CF) vaccine, respectively, virus-neutralizing and IgG- and IgM-ELISA antibodies were detected in the serum, but no antibody was detected in the tracheal washes of the vaccinated chickens. More apparent antibody response was seen in chickens vaccinated with the CA vaccine than with the CF vaccine. The antibody titers did not correlate closely with the protection against challenge with ILT virus. After subcutaneous injection of either CA or CF vaccine, ILT virus was isolated from the liver, spleen, thymus, lungs and other organs of the chickens from 1 to 6 days after injection, and there was no correlation of the isolation rate for the CA-vaccinated and the CF-vaccinated chickens.

Animals↗
PubMed1994

t-PA activity in peripheral blood obtained from pregnant women.

Concentrations of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI) were measured in blood obtained from pregnant women to elucidate the fluctuations in the fibrinolytic system which occur during the course of pregnancy. The t-PA activity was measured with a modified bioimmunoassay using anti-t-PA monoclonal antibody (SP-322) against a single chain of recombinant t-PA. The t-PA antigen was measured by ELISA using the same antibody. PAI activity was determined with a competitive inhibition assay of t-PA activity. In early pregnancy, t-PA activity was found to be close to the standard range seen in nonpregnant women, and gradually decreased during the course of pregnancy, then recovered to rise to the normal range within 48 hours after delivery. The t-PA antigen and PAI activity levels rose slowly during the course of pregnancy, and fell promptly after delivery. t-PA activity and t-PA antigen in levels in umbilical cord blood were higher after vaginal delivery than after cesarean section. These findings suggest that there may be an important physiological balance of the fibrinolytic system between mother and fetus during the course of pregnancy and the puerperium.

Female↗
PubMed1994

Prognostic impact of the period between surgery and postoperative irradiation in esophageal carcinoma.

One hundred and sixty-two esophageal carcinomas curatively resected and followed by postoperative irradiation were analyzed to investigate whether the delay of postoperative irradiation affected the patients' prognosis. The period of 40 or more days between surgery and postoperative irradiation caused significantly worse survival rates, and this fact was true even if the survival rates were corrected by the other significantly important prognostic factors: age and tumor staging. The incidence of infield recurrence and cancerous death were higher in the patients with the waiting period of 40 or more days. Significant repopulation of residual tumor cells in curatively resected esophageal carcinomas begins 40 days after surgery, therefore, postoperative irradiation should be started within 40 days after a radical resection. The difference of survival rates as related to the waiting period became clear after the follow-up of more than four years. The prognostic difference of subclinical tumors seems to be uncovered several years after treatment.

Adult↗
PubMed1994

Locally delivered minocycline and guided tissue regeneration to treat post-juvenile periodontitis. A case report.

A case of post-juvenile periodontitis in a 28-year-old female patient is described along with new periodontal treatment modalities. Administration of minocycline-HCl with local drug delivery system was introduced as a part of initial periodontal therapy following microbiological and immunological examinations. The lesions were subsequently treated by guided tissue regeneration, which resulted in considerable gain of attachment with minimal recession of marginal gingiva. This observation suggests that the local delivery of antibiotics and regenerative therapy may prove to be effective alternative modalities in treatment of post-juvenile periodontitis.

Administration, Topical↗
PubMed1994

[Morphometric study of age-related changes of the spinal cord].

The relation of aging to the length of the spinal cord and to the cross-sectional area at the levels of C6 and L3 of the spinal cord was studied in 140 autopsy cases who between the age of 47 to 105 without spinal cord lesions. In addition the effect of being bed-ridden on the spinal cord was studied in 11 of 140 cases. As pathological controls, we referred to 40 autopsy cases with compression change of the cervical cord. The length of the spinal cord had no correlation with aging but had a significant positive correlation with the height of the subject. A significant decrease in the cross-sectional area of the spinal cord was observed after the age of 80, in particular at C6. However, the extent of the decrease was not as serious as that of pathological control cases. Decrease of cross-sectional area was associated with that of white matter area. In addition, effect of being bed-ridden on the spinal cord was reflected in a significant decrease of the grey matter of the lumbar cord.

Adult↗
PubMed1994

[Trigonoplasty for vesicoureteral reflux--from open surgery to endoscopic surgery].

To evaluate endoscopic trigonoplasty compared to open trigonoplasty for vesicoureteral reflux, we analyzed clinical results, complications, the use of analgesics for postoperative pain and bladder irritability and postoperative length of hospitalization. One of six patients undergoing endoscopic trigonoplasty subsequently underwent open trigonoplasty due to failure of trocar placement, therefore, 7 patients having vesicoureteral refluxy renoureteral units underwent open trigonoplasty and 5 patients with vesicoureteral reflux 7 renoureteral units underwent endoscopic trigonoplasty. Mean operative time was 143 +/- 48 minutes for open surgery and 185 +/- 54 minutes for endoscopic surgery. Vesicoureteral reflux disappeared in 8 renoureteral units but was worse in one unit after open trigonoplasty, while vesicoureteral reflux subsided in 6 units and improved in one unit from grade II to grade I after endoscopic trigonoplasty. There were no intraoperative complications after open surgery, while one patient had pneumoperitoneum due to inadequate placement of a trocar during endoscopic surgery. There were no early postoperative complications after endoscopic surgery. However, 2 patients developed hematuria after open surgery. The degree of postoperative pain and irritability following endoscopic trigonoplasty was lower than that after open trigonoplasty and analgesics were used less frequently after endoscopic surgery. The mean postoperative hospital stay was 16.7 +/- 3.2 days for open surgery and 14.4 +/- 2.9 days for endoscopic surgery. These results indicate that endoscopic trigonoplasty is a useful procedure for vesicoureteral reflux because it is minimally invasive.

Adolescent↗
PubMed1994

[A study on predicting factors of the effect of intra-arterial infusion chemotherapy in patients with bladder cancers: the usefulness of in-vitro chemisensitivity test measuring intracellular ATP contents (ATP assay)].

We studied a relationship between in vitro sensitivity of the tumors to anti-cancerous drugs and histopathological effectiveness of an intra-arterial infusion chemotherapy in 15 patients with bladder cancers. The in vitro sensitivity test was performed by measuring intra-cellular ATP contents (ATP assay). The intra-arterial chemotherapy were performed by injecting methotrexate (MTX), adriamycin (ADM) and eisplatin (CDDP) from the internal iliac artery. When the intra-cellular ATP contents of the tumor cells treated with an anti-cancerous drug decreased to less than 50% of the untreated tumor cells, the tumor was evaluated as sensitive to the drug. The effectiveness of the chemotherapy were histopathologically evaluated by a pathologist according to the response criteria for bladder cancer treatment. When the histopathological responses of higher than grade 2 were observed in the tumor, the chemotherapy was evaluated as effective. In 8 of 9 tumors sensitive to ADM, chemotherapy were effective histopathologically and in all 6 tumors resistant to ADM, histopathological response of the chemotherapies were poor. The overall coincidence ratio between sensitivity to ADM and the histopathological effectiveness of the chemotherapy was 93%, showing statistically significant correlation. In 7 of 12 tumors sensitive to CDDP, the chemotherapies were effective and in 2 of 3 tumors resistant to CDDP, the chemotherapies were ineffective. Although the overall coincidence ratio between the sensitivities to CDDP and chemotherapeutic effectiveness was 60%, there was no significant correlation between them. In 7 of 8 tumors sensitive to both of ADM and CDDP, the chemotherapies were effective and in 6 of 7 tumors resistant to at least one of them, the chemotherapies were ineffective. (ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1994

[Laparoscopic pelvic lymphadenectomy in prostate cancer].

We described the clinical results and efficacy of laparoscopic pelvic lymphadenectomy for localized prostate cancer. This procedure was followed by radical prostatectomy, if metastasis was not found in frozen section. In the presence of positive nodes, optional treatment, such as TUR or castration, other than radical prostatectomy was performed. We performed laparoscopic lymphadenectomy on twenty seven patients between April 1992 and September 1993. They range from 52 to 78 years in age and consist of 4 patients with stage A2, 17 with stage B, and 6 with stage C. We dissected the obturator lymph nodes on bilateral sides. The average operating time was 162 minutes (range 86 to 320 minutes). The average number of nodes removed from the right side was 7.1 +/- 5.9 and 6.1 +/- 4.5 from the left side, which was comparable to the number of lymph nodes obtained by open dissection. Colon injury occurred in one patient, which was managed by laparotomy procedure. Nodal metastases were found in 6 patients by frozen section, and in 10 patients by permanent section. This discrepancy suggested that two-staged operation might be preferable for the localized prostate cancer. Six patients were given suitable therapies besides radical prostatectomy. Laparoscopic pelvic lymphadenectomy is a safe and useful procedure for prostate cancer, especially for the patients who are likely to have nodal metastasis.

Aged↗
PubMed1994

Pharmacokinetics of amlodipine and its occupancy of calcium antagonist receptors.

We characterized the occupancy of dihydropyridine (DHP) calcium antagonist receptors by amlodipine in spontaneously hypertensive rats (SHR) in relation to its pharmacokinetics. Oral administration of amlodipine (10 mg/kg) in SHR produced a significant (20-70%) decrease in the number of specific (+)[3H]PN 200-110 binding sites in cardiac tissues 0.5-18 h later, and the effect was greatest 3 h later. In these rats, there was little change in cerebral cortical (+)[3H]PN 200-110 binding. Occupancy of cardiac calcium antagonist receptors after oral administration of amlodipine correlated well with its plasma concentration. In vitro blockade of cardiac (+)[3H]PN 200-110 binding sites induced by amlodipine also persisted after the tissues were washed by centrifugation and suspension, whereas that induced by nifedipine was reversible under these conditions. Thus, our results suggest that the gradual onset and long-lasting pharmacologic effect of amlodipine are due to its slow binding kinetics (association and dissociation) of cardiovascular receptor sites in addition to its slow pharmacokinetics.

Amlodipine↗
PubMed1994

Raynaud's phenomenon of fingers and toes among vibration-exposed patients.

Eleven patients with Raynaud's phenomenon of the toes as well as the fingers were encountered among about 1,000 vibration-exposed patients. They consisted composed of four chain-saw operators, five rock drillers, a stone quarrier and a welder in a shipyard. All the cases were examined carefully for differential diagnosis, but there were no particular abnormalities in hematological, immunological and homodynamic examinations. The rock drillers, quarrier and welder had direct vibration exposure of the foot, which was considered to be responsible for their Raynaud's phenomenon of the toe. Four chain-saw operators, who had been little exposed to vibration of the foot directly, were examined further on skin temperature of fingers and toes every three hours except at night and in a 30-min cold provocation test at 5 degrees C. The skin temperature of both their fingers and toes was lower than in age-matched healthy controls. The chain-saw operators started to work in the 1960's and early in the 1970's, when the chain saw vibration level was high. It is, hence, considered that they were exposed to strong vibration of the hand from chain saws, and then suffered severe Raynaud's phenomenon of both fingers and toes.

Aged↗
PubMed1994

Pathological changes of finger and toe in patients with vibration syndrome.

Pathological findings of the fingers and toes were studied in finger and toe skin specimens from 21 male patients with vibration syndrome and 13 referent male cadavers. Thickening of the medial muscle layer of small arteries or arterioles, and increase of collagen fibers in the connective tissues, especially in perivascular regions, were noted in not only the finger but also the toe in patients with vibration syndrome. The ratio of the media/external diameter in the finger and toe was significantly greater in the patients than in the referents, even in the patients who had operated chain saws, bush cutters or grinders and had not been exposed to vibration of the foot directly. And the ratio in the finger was approximately parallel with that in the toe in the same subject. The present findings pathohistologically confirmed the existence of circulatory disturbances in the feet as well as the hands. The medial thickening of arteries and perivascular fibrosis in the toe can result from not only direct vibration exposure of the foot, but also long-term repeated vasoconstriction and circulatory disturbances in the foot through the activation of the sympathetic nerve system caused by hand-arm vibration.

Aged↗
PubMed1994

Vibration exposure and prevention in Japan.

Working conditions of vibration exposure have generally improved, but many difficult problems must be solved such as (1) hygienic improvements in a variety of vibrating tools; (2) improving working conditions, for example, by limiting the time of operation in spite of economic difficulties such as those faced by those who work on a piece rate basis; (3) gathering more complete information about the risk population because of the large number of self-employed in informal employment sectors; and (4) finding work places after rehabilitation for patients, particularly in mountainous rural areas or in small scale industries. Historical observation of vibration and preventive measures in Japanese national forests was presented on the basis of the results of a retrospective cohort study in Kyushu, Japan. Prevalence rate of VWF remarkably changed from 58.4% in the groups that began to operate chain saws in 1960 to only a few cases in the groups who started the operation after 1971. When we compare the relationships between the results of long term cohort study and the consequences of preventive measures of vibration syndrome, the most important factor is the decrease of vibration exposure (improvement in chain saws plus the time restriction system). The comprehensive prevention system used in Japanese national forests consists of the following: (1) Health care system; (2) Work regulation system; (3) System for improving mechanized tools; (4) Warming system to protect against cold conditions; and (5) Education and training system.

Humans↗
PubMed1994

Research into hand-arm vibration syndrome and its prevention in Japan.

Research on vibration syndrome in Japan began in the 1930s with studies of the disorder among railway, mining and shipyard workers. In 1947, the Ministry of Labor decided vibration syndrome among operators of rock drills and riveters etc. was an occupational disease. Industrial developments in the 1950s and 1960s promoted the survey of vibration syndrome in mining, stone quarrying and forestry. The Ministry of Labor (1965) and the National Personnel Agency (1966) legally recognized vibration syndrome among chain saw operators as an occupational disease. Guidelines for prevention and early therapy were issued in the 1970s and 80s. From the late 1970s into the 1980s, research focused on the clinical picture, diagnostic methods and therapy. In pathophysiology, advances were made in research into the autonomic nervous system during the 1980s. The 1970s and 80s saw a steady reduction in risk from technological change and working conditions, and advances in medical care, education and meteorological forecasting. A comprehensive prevention system established in the 1980s in the Japanese forest industry involved: 1) work restrictions, 2) an improved health care system, 3) advances in the design of vibrating tools, handle-warming devices, and 4) improved worker education. This comprehensive preventive system was legally introduced into other industries, resulting in a rapid decrease in the incidence of vibration syndrome in Japan.

Arm↗
PubMed1994

Correlations among examination findings, subjective symptoms and classification of stages in vibration syndrome.

From data collected in 1966, 1973, 1986 and 1989, we analyzed the correlations among examination findings, subjective symptoms, stages in the disorder of vibration syndrome and vibration exposure. As vibration syndrome progressed and vibration exposure accumulated, abnormality of examination findings, the prevalence of vibration induced white finger (VWF), numbness (N) and other subjective symptoms increased. Abnormality of examination findings and prevalence of subjective symptoms in the VWF(+) N(+) group were greatly different from those in the VWF(-) N(-) group. Both findings and symptoms showed closer correlations with VWF(+) than with N(+). Stages in the disorder traced the progression from VWF(-)N(-) to VWF(-)N(+), then to VWF(+)N(+/-), and finally to VWF(+/++)N(+/++). Pathophysiologically, it seems that VWF(+) and N(+) relayed many more cold and pain signals from the hand to the central nervous system. Such signals may activate autonomic nervous activity. In the recovery, subjective symptoms correlated more closely with N(+) than with VWF(+). This is because VWF involves the autonomic nervous system's hyperactivity and hypersensitivity to cold, both of which subside gradually in the recovery; N, however, involves pathological changes in nerve tissue which are irreversible.

Adult↗
PubMed1994

Large clear cell adenoma of the parathyroid in a patient with MEN-1 syndrome. Ultrastructural study of the tumour exhibiting unusual RER formations.

A 48 year old man presented with hyperparathyroidism and acromegaly. Although pancreatic tumour was not demonstrated, the diagnosis of MEN-1 syndrome was made. The parathyroid adenoma was removed surgically and investigated by histology and transmission electron microscopy and was diagnosed as large clear cell adenoma with extensive deposition of glycogen. Much of the endoplasmic reticulum was present in two special forms: annulate lamellae and the rare rail-like configurations both of which showed continuity with the conventional RER as well as with each other. No obvious correlation was apparent between presence of special RER formations and growth rate or endocrine activity of tumour; they may be regarded as signs of cellular dedifferentiation.

Acromegaly↗
PubMed1994

Integrin regulatory switching in development: oscillation of beta 5 integrin mRNA expression during epithelial-mesenchymal interactions in tooth development.

Integrin receptors for extracellular matrix molecules are thought to play important roles in morphogenesis since they mediate aspects of embryonic cell adhesion and migration. Using in situ hybridization, the mRNA expression pattern of the beta 5 integrin receptor subunit was examined during murine tooth development, a classical system for studying morphogenesis. In developing tooth, high-level expression of beta 5 integrin mRNA alternates from epithelium to mesenchyme and back to epithelium. Each switch in localization occurs within one day. These results demonstrate that an integrin mRNA can be precisely and rapidly up- and down-regulated over unexpectedly short time spans, and that expression can oscillate between adjacent, interacting epithelial and mesenchymal tissues during morphogenesis. This rapid modulation of mRNA expression suggests a potential regulatory role for the beta 5 integrin receptor in morphogenesis.

Animals↗
PubMed1994

Cerebral protective effects of VA-045, a novel apovincaminic acid derivative, in mice.

The cerebral protective effects of VA-045, a novel apovincaminic acid derivative, were investigated in mice under conditions of normobaric hypoxia, histotoxic anoxia by potassium cyanide (KCN), and complete ischemia. VA-045 and thyrotropin releasing hormone (TRH) showed a significant protective effect on normobaric hypoxia. The duration of action of the protective effect of VA-045 was longer than that of TRH. VA-045 but not TRH significantly prolonged the survival time following administration of KCN. VA-045 and TRH showed a positive effect on complete ischemia, and the duration of the protective effect of VA-045 was longer than that of TRH. Beneficial effects of VA-045 for treating cerebral hypoxia, anoxia and ischemia will be discussed.

Animals↗