Search PubMed⌕ Search

Biomedical subjects

J Yamamoto

Publications and source records attributed to J Yamamoto.

At least 55 records · Page 3Linked to original sources

Effects of vitamin E and sesamin on hypertension and cerebral thrombogenesis in stroke-prone spontaneously hypertensive rats.

The preventive effects of sesamin, a lignan from sesame oil, and vitamin E on hypertension and thrombosis were examined using stroke-prone spontaneously hypertensive rats (SHRSP). At 5 weeks of age the animals were separated into four groups: (i) a control group; (ii) a vitamin E group, which was given a 1,000 mg alpha-tocopherol/kg diet; (iii) a sesamin group, given a 1,000 mg sesamin/kg diet; and (iv) a vitamin E plus sesamin group, given a 1,000 mg alpha-tocopherol plus 1,000 mg sesamin/kg diet for 5 weeks from 5 to 10 weeks of age. Resting blood pressure was measured by the tail-cuff method once weekly. A closed cranial window was created and platelet-rich thrombi were induced in vivo using a helium-neon laser technique. The number of laser pulses required for formation of an occlusive thrombus was used as an index of thrombotic tendency. In control rats, systolic blood pressure and the amount of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) became significantly elevated with age. However, the elevation in blood pressure and 8-OHdG were significantly suppressed in rats administrated vitamin E, sesamin, or vitamin E plus sesamin. At 10 weeks, the number of laser pulses required to induce an occlusive thrombus in arterioles of the control group was significantly lower than in the other groups (p<0.05). These results indicate that chronic ingestion of vitamin E and sesamin attenuated each of elevation in blood pressure, oxidative stress and thrombotic tendency, suggesting that these treatments might be beneficial in the prevention of hypertension and stroke.

8-Hydroxy-2'-Deoxyguanosine↗

Changes in Ca2+ signaling and contractile protein isoforms in smooth muscle cells from guinea pig ileum during culture.

Single smooth muscle cells (SMCs) isolated from guinea pig ileum using collagenase and papain were cultured on laminin-coated dishes in MEM containing fetal calf serum. Temporal changes in intracellular calcium ion concentration in response to carbachol and to ATP were investigated using fluo-3/AM and fluorescence microscopy. It was observed that carbachol caused an increased intracellular calcium ion in freshly isolated single SMCs but a reduced or negative response of cultured SMCs before confluence. On the other hand, ATP was observed to cause an increase in the calcium ion content of SMCs throughout the culture. SDS-PAGE and Western blot analyses revealed changes in the expression of contractile proteins as follows. l-Caldesmon and non-muscle type myosin heavy chain (NMHC) (considered to be marker molecules for dedifferentiation in smooth muscle cells) and non-muscle type tropomyosin were not observed in freshly isolated single SMCs. l-Caldesmon and NMHC appeared in the cultured SMCs within 2 days and the tropomyosin isoform was observed 6 days following seeding. Simultaneously, smooth muscle type myosin heavy chain (SMHC) decreased strikingly and the 41 kDa tropomyosin monomer was lost. The content of alpha-actin decreased gradually to a minimum on day 6 when non-muscle type tropomyosin appeared, and the cells began to proliferate rapidly. These results suggest that the loss of contractility in cultured smooth muscle cells is more closely related to changes in contractile protein profiles than to receptor-mediated signal transduction and that in addition to NMHC and l-caldesmon, non-muscle type tropomyosin may be useful as a marker molecule for de-differentiation of smooth muscle cells.

Actins↗

[Surgical treatment of liver metastases from colorectal cancer patient selection and oncological outcome].

The indications for surgical resection of liver metastases from colorectal cancer remain controversial. Clinical, pathological, and outcome data for 418 consecutive patients undergoing hepatectomy between 1984 and 1998 were examined. The over-all 5-year survival rate was 42%, and the 10-year survival rate was 31%. The 5-year survival rate of patients with four or more nodules was 24%, with 20 patients surviving for more than 5 years. Five factors were found to be significant and independent predictors of poor long-term outcome by multivariate analysis. The preoperative scoring system reported by Fong et al was double-checked in our 418 patients and was found to be useful to predict long-term outcome after hepatectomy. It is clear that liver resection alone has limitations. Therefore clinical risk scoring (CRS) and effective intravenous systemic chemotherapy to prevent recurrence both in the remaining liver and lung should be established to improve survival outcome in patients with poor prognostic factors after liver resection.

Colorectal Neoplasms↗

Food allergy and atopic dermatitis in low birthweight infants during early childhood.

UNLABELLED: The prevalence rates of food allergy and atopic dermatitis in low birthweight infants were evaluated. In Fukuoka City, Japan, between July 1994 and September 1997, sufficient information including birthweight, gestational age, sex, feeding method and a history of food allergy was obtained from questionnaires at the well-baby check-ups of 21766 infants (18 mo of age) and 4378 children (3 y of age). All the children were examined by pediatricians with regard to the existence of atopic dermatitis. The prevalence rate (8.1%) of food allergy in infants with low birthweight (<2,500 g) was significantly lower than that (11.2%) in infants with normal birthweight (> or = 2,500 g) at 18 mo of age (p = 0.0002). Atopic dermatitis was also observed at a lower prevalence rate (1.2%) in infants with low birthweight than in those with normal birthweight (2.3%) at the same age (p = 0.0041). However, this significance was lost at 3 y of age. Other characteristics including male sex and breast-feeding showed independent risks for the development of food allergy and atopic dermatitis at both ages. CONCLUSION: This study found that low birthweight was significantly associated with a lower risk of both food allergy and atopic dermatitis at 18 mo of age.

Breast Feeding↗

[A pediatric case of intractable complex partial seizures associated with mesial temporal lobe astrocytoma: usefulness of interictal epileptiform discharges in the present case].

The patient was a 10-year-old male with normal developmental milestones. He had medically intractable complex partial seizures since the age of 7 years. At the age of 10 years, he had focal motor seizures of the right face, and a head CT scan showed a calcified lesion in the left mesial temporal region. The tumor exhibited low intensity on T 1-weighted and high intensity on T 2-weighted MR images, and was not enhanced by gadolinium-diethylenetriamine pentaacetic acid. Interictal SPECT showed hypoperfusion in the left temporal region. One-day video/EEG monitoring revealed very frequent epileptiform discharges which occurred only during sleep period exclusively in the left anterior-to-middle temporal region. The patient underwent lesionectomy with the guidance of electrocorticography. The histological study of the resected tissue showed astrocytoma. After surgery he has had no seizures for 10 months. It was concluded that very frequent interictal epileptiform discharges strictly localized to the temporal lobe at which MRI-identified tumor was present could be predictive of epileptogenic zone in the present patient in whom clinical symptoms and the results of other studies were also concordant.

Astrocytoma↗

[Effects of volume and concentration of lidocaine on epidural anesthesia].

We studied 40 patients scheduled for gynecological surgery to evaluate the effects of volume and concentration of lidocaine on epidural anesthesia. We injected lidocaine 300 mg as 1% (30 ml) or 2% (15 ml) through epidural catheter at L 1/2. There was no significant difference in the spread of sensory blockade (cold and pain) and the Bromage scale between the two lidocaine solutions. This result suggests that volume and concentration of lidocaine do not affect the effects of epidural anesthesia.

Adult↗

[Acute onset of tuberculous meningoencephalitis presenting with symmetric linear lesions in the bilateral thalamus: a case report].

A 18-year-old woman was admitted to our hospital because of high fever and headache. Nuchal stiffness was present, and a CSF examination showed lymphocyte-domonant pleocytosis and a decreased level of glucose. Although antibiotics, aciclovir and an antimycotic drug were administered, disturbance of consciousness, involuntary movements, and pyramidal tract signs appeared. Soon after the medications were changed to antituberculous medicines, the meningoencephalitis started to subside, and was finally cured. Judging from the clinical findings, the CSF findings, the effectiveness of antituberculous medicines, an elevated ADA level in CSF, and positive conversion in tuberculin tests, the final diagnosis was made as tuberculous meningoencephalitis. At the severest stage of the disease, a brain MRI showed symmetric, linear lesions without the effect of Gd-enhancement in the bilateral thalamus, which thereafter disappeared along with the healing of the illness. From all these things, we conclude that thalamic and other parenchymal lesions should be kept in mind in case of acute tuberculous meningoencephalitis.

Acute Disease↗

Inhibitory effect of various thrombin inhibitors on shear-induced platelet function and dynamic coagulation.

We assessed the effects of active site-directed, fibrinogen recognition exosite (FRE)-directed and bifunctional thrombin inhibitors, on shear-induced platelet reactivity (adhesion/aggregation) and dynamic coagulation (coagulation of flowing blood). An in vitro test for shear-induced haemostatic plug formation and dynamic coagulation (haemostatometry) was employed using non-anticoagulated rat blood. The active site-directed inhibitors (argatroban, P891, P899) caused inhibition of platelet reactivity and coagulation at 1-, 100- and 100-microM concentrations, respectively. Bifunctional inhibitors (P553, P1053) exerted inhibitory effects at 0.1 microM. A dimeric bifunctional inhibitor P824 caused significant inhibition at 1 microM. The FRE-directed inhibitor (P960) inhibited shear-induced platelet reactivity at 10 microM but the dynamic coagulation at 1 microM. Combination of active site-directed argatroban and FRE-directed P960 did not show any synergistic effect. The most potent inhibition was observed in monomeric bifunctional inhibitors. The inhibitory effects were compared with the K(i) values against human thrombin and with the IC(50) values against fibrin clot formation. The minimum effective concentrations on shear-induced platelet reactivity and dynamic coagulation were comparable with the IC(50) values, but not with the K(i) values.

Animals↗

Adoptive immunotherapy to lower postsurgical recurrence rates of hepatocellular carcinoma: a randomised trial.

BACKGROUND: Postsurgical recurrence of hepatocellular carcinoma (HCC) is frequent and fatal. Adoptive immunotherapy is active against HCC. We assessed whether postoperative immunotherapy could lower the frequency of recurrence. METHODS: Between 1992 and 1995, we did a randomised trial in which 150 patients who had undergone curative resection for HCC were assigned adoptive immunotherapy (n=76) or no adjuvant treatment (n=74). Autologous lymphocytes activated vitro with recombinant interleukin-2 and antibody to CD3 were infused five times during the first 6 months. Primary endpoints were time to first recurrence and recurrence-free survival and analyses were by intention to treat. FINDINGS: 76 patients received 370 (97%) of 380 scheduled lymphocyte infusions (mean cell number per patient 7.1x10(10) [SD 2.1]; CD3 and HLA-DR cells 78% [16]), and none had grade 3 or 4 adverse events. After a median follow-up of 4.4 years (range 0.2-6.7), adoptive immunotherapy decreased the frequency of recurrence by 18% compared with controls (45 [59%] vs 57 [77%]) [corrected] patients. Time to first recurrence in the immunotherapy group was significantly longer than that in the control group (48% [37-59] vs 33% [22-43] at 3 years, 38% [22-54] vs 22% [11-34] at 5 years; p=0.008). The immunotherapy group had significantly longer recurrence-free survival (p=0.01) and disease-specific survival (p=0.04) than the control group. Overall survival did not differ significantly between groups (p=0.09). INTERPRETATION: Adoptive immunotherapy is a safe, feasible treatment that can lower recurrence and improve recurrence-free outcomes after surgery for HCC.

Adult↗

Critical behavior of layer compression modulus near the smectic- A-smectic- C(*)(alpha) transition

The layer compression modulus was measured near the smectic- A-smectic- C(*)(alpha) phase transition in a chiral smectic liquid crystal. The layer compression modulus B shows marked pretransitional effects above the phase transition. The critical softening of B can be fit to a simple power law. It is described by the theoretical description based on the renormalization-group method and seems to suggest a crossover behavior. These effects clearly show that the transition is not of the Landau mean-field type.

Journal Article↗

Fibrous pseudocapsule of metastatic liver tumors from colorectal carcinoma. Clinicopathologic study of 152 first resection cases.

BACKGROUND: The presence of pseudocapsules of liver tumors has been recognized in hepatocellular carcinoma and is known to be a favorable prognostic factor. Although several studies have reported pseudocapsules around metastatic liver tumors, to the authors' knowledge there have been few evaluations of the clinical significance of such features in patients with metastatic colorectal carcinoma. METHODS: A clinicopathologic study was conducted in 152 patients who underwent initial hepatic resection for metastatic colorectal carcinoma. RESULTS: The presence of fibrous tissue between the tumor and the surrounding hepatic parenchyma was noted in 93 of the 152 patients (61%) with colorectal liver metastases. These patients were classified as having a thin pseudocapsule (n = 46) or a thick pseudocapsule (n = 47), according to the number of collagen bundles (< 10 or >/= 10) between the tumor and the hepatic parenchyma in histologic sections. Pathologically, the presence and thickness of the fibrous pseudocapsule were related closely to less invasiveness into adjacent vessels (P = 0.004) and the presence of macroscopic intrabile ductal invasion (P = 0.008). The postresection survival was significantly better in patients with thick or thin pseudocapsules than in those without a pseudocapsule (3-year and 5- year cumulative survival rates of patients with no, thin, and thick pseudocapsules were 41% and 31%, respectively, 71% and 64%, respectively, and 88% and 88%, respectively; P < 0.001). In a multivariate analysis using the Cox proportional hazards model, after adjusting for other potential prognostic factors (vascular invasion, bile ductal invasion, number of tumors, tumor size, and curativeness of surgery), the presence of a fibrous pseudocapsule was an independent predictor of a favorable outcome after hepatic resection. CONCLUSIONS: The presence of fibrous tissue between the tumor and the liver parenchyma was a promising indicator of a better prognosis after resection in patients with colorectal liver metastases.

Adult↗

Adjuvant effect of antibodies against von Willebrand Factor, fibrinogen, and fibronectin on staphylokinase-induced thrombolysis as measured using mural thrombi formed in rat mesenteric venules.

The change in thrombus mass during thrombolytic therapy is thought to be the difference between its growth and its degradation induced by thrombolytic agents. Platelets play a pivotal role in arterial thrombosis and bind to each other and to exposed subendothelial matrices via adhesive proteins such as von Willebrand Factor, fibrinogen, and fibronectin. The aim of the present study was to assess whether administration of antibodies against these adhesive proteins, in conjunction with plasminogen activator, could enhance the degradation of platelet-rich thrombus. Mural platelet-rich thrombi were formed in rat mesenteric venules using He-Ne laser irradiation. Recombinant staphylokinase was infused continuously and polyclonal antibodies against adhesive proteins were given by bolus injection. The thrombolytic process was analysed using computer-enhanced image analysis software. Administration of each of the antibodies enhanced staphylokinase-induced thrombolysis.

Adjuvants, Immunologic↗

Cystic liver metastases from colorectal cancer.

BACKGROUND AND OBJECTIVES: Cystic liver metastases from colorectal cancer are rarely reported. METHODS: Clinicopathological and radiological analyses were performed on six cases of cystic liver metastases from colorectal cancer. RESULTS: Computed tomography or ultrasound findings for the tumors were atypical for metastases of colorectal cancer, and the lesions needed to be differentiated from cystadenocarcinoma and benign tumors. The histological findings were peculiar: the central portions of the tumors contained necrotic tissue or areas of hemorrhage, and adenocarcinoma cells were found predominantly outside well-developed fibrous capsules. CONCLUSIONS: Clinicopathological observations suggested that these metastatic tumors had the potential to grow rapidly, but, unexpectedly, the patients had favorable prognoses.

Adenocarcinoma↗

Insulin-like growth factor-I is expressed by avian flexor tendon cells.

Cells in normal tendon are in a resting G0 state, performing maintenance functions. However, traumatic injury introduces growth factors such as platelet-derived growth factor and insulin-like growth factor from blood as well as activates endogenous growth factors. These factors stimulate migration and proliferation of tendon cells at the wound area. Tendon cells require growth-promoting factors to transit the cell cycle. To evaluate the contribution of endogenous growth factors in tendon, extracts of the epitenon and internal compartment of avian flexor tendon as well as medium of cultured cells from the epitenon (tendon surface cells) and internal tendon (tendon internal fibroblasts) were collected to assess their ability to stimulate DNA synthesis. Acid-ethanol extracts of tissues and medium were chromatographed on a P-30 molecular sieve column and assayed for mitogenic activity by quantitating [3H]thymidine incorporation into tendon cell DNA. The extract from the internal tendon compartment was more stimulatory for DNA synthesis than that from the epitenon, particularly when tested on tendon internal fibroblasts. However, conditioned medium fractions from surface epitenon cells stimulated DNA synthesis to a high degree on both tendon surface cells and tendon internal fibroblasts. Conditioned medium from tendon internal fibroblasts was also stimulatory. An anti-insulin-like growth factor-I antibody ablated most of the mitogenic activity present in both tissues and conditioned medium. The levels of acid-extractable insulin-like growth factor-I in tendon were determined by competitive radioimmunoassay as 1.48+/-0.05 ng/g tissue for the epitenon and 3.83+/-0.03 ng/g tissue for the internal compartment. Results of Western immunoblots of conditioned medium revealed insulin-like growth factor-I at the 7.5 kDa position. Cultured tendon surface cells and tendon internal fibroblasts as well as cells in intact flexor tendon expressed insulin-like growth factor-I mRNA detected by reverse transcriptase-polymerase chain reaction. In situ hybridization histochemistry positively identified insulin-like growth factor-I mRNA in tendons from 52-day-old chickens. Platelet-derived growth factor was not detected at the protein or message levels. Furthermore, tendon surface cells and tendon internal fibroblasts both expressed receptors for insulin-like growth factor-I detected by flow cytometry. These data suggest that tendon cells express insulin-like growth factor-I mRNA and synthesize insulin-like growth factor-I in both the epitenon and the internal compartment of tendon, which is present in an inactive form, most likely bound to insulin-like growth factor-binding proteins.

Animals↗

Surgical results for hepatocellular carcinoma with macroscopic portal vein tumor thrombosis.

BACKGROUND: The longterm results after liver resection for hepatocellular carcinoma with macroscopic tumor thrombus of the portal vein are unclear. STUDY DESIGN: The records of 47 HCC patients with tumor thrombus in the segmental portal branch (n = 33) and the first portal branch or portal vein trunk (n = 14) were reviewed in this study. Survival rates of the patients were calculated with regard to 14 dinicopathologic variables. A log-rank analysis was performed to identify which variables predicted the prognosis. RESULTS: Overall 1-, 3-, and 5-year survival rates were 53.9%, 33.2%, and 23.9%, respectively. The indicators of a favorable prognosis included curative liver resection, tumor size less than 10 cm in diameter, and absence of intrahepatic metastases. CONCLUSIONS: Liver resection should be considered a therapeutic option for hepatocellular carcinoma with macroscopic portal vein tumor thrombus when the tumor is small and curative liver resection can be expected.

Adult↗

Splenectomy in patients with hepatocellular carcinoma and hypersplenism.

BACKGROUND: Hypersplenism secondary to portal hypertension is common in hepatocellular carcinoma (HCC), but surgeons still face the unresolved problem of how to manage HCC patients with hypersplenism. STUDY DESIGN: The records of 48 patients with HCC and hypersplenism were retrospectively examined and postoperative changes in platelet counts, serum total bilirubin levels, and dinical staging scores were analyzed to evaluate the clinical value of combined splenectomy and liver resection. Hepatectomy and splenectomy were performed as a two-stage operation in 13 patients and synchronously in 35. RESULTS: Postoperative platelet counts were significantly increased, and serum total bilirubin levels were significantly decreased. Clinical staging scores were also reduced after splenectomy in patients who underwent splenectomy before hepatectomy. CONCLUSIONS: Synchronous or metachronous splenectomy can increase the safety of hepatectomy in selected patients with HCC by reducing both the likelihood of bleeding complications and bilirubin overload.

Aged↗