Arterial thrombosis model with photochemical reaction in guinea-pig and its property.

We have already developed an arterial thrombosis model in the rat femoral artery which utilized photochemical reaction between systemically injected rose bengal and transillumination of a green light with 540 nm wave length from the outside of the vessel. In the present study, we applied this model to guinea-pigs in order to produce a more suitable thrombus model for evaluation of antithrombotic drugs which act on the prostaglandin cascade. In the guinea-pigs, the irradiated femoral artery was completely occluded in 7 min after the injection of rose bengal (10 mg/kg) in a similar manner to the rats. The processes of primary endothelial injury and the subsequent formation of thrombus during this manipulation were observed by the electron microscopy. Pretreatment with aspirin and Y-20811, a thromboxane synthetase inhibitor, significantly prolonged the time required for occlusion in the guinea-pigs, while these drugs were ineffective in the rats. The antithrombotic effect of vapiprost, a thromboxane A2 receptor antagonist, was more pronounced in the guinea-pigs than the rats. In conclusion, this model in guinea-pigs is more suitable for evaluating antithrombotic drugs, particularly, the action of which is exerted involving the prostaglandin cascade.     

The results of an investigation of the various factors influencing the late patency ratio of coronary bypass grafting

The purpose of this communication was to find out the factors influencing the late patency ratio of coronary artery bypass grafts of 42 patients in our institution. The following results were obtained: 1. The size of the measured diameters of coronary arteries and the graft flow rates were correlated well to the late patency ratio (p less than 0.05). 2. The regular physical exercise trainings were significantly important to keep patent grafts (p less than 0.01). 3. In blood serum studies, serum uric acid levels were significantly lower (p less than 0.05), the average mean HDL cholesterol levels were much higher (p less than 0.001) and the ratio of total cholesterol to HDL cholesterol were significantly lower in the group with late patent grafts than with grafts occluded. Therefore, we found out the variables affecting graft patency ratio which were examined by a stepwise method were the diameter of the coronary artery, regular physical exercise training, the average of lower serum uric acid levels and higher HDL cholesterol levels. The multiple coefficient for these four variables was 0.562 (p less than 0.001) and the contribution was 31.6%. According to the base of this studies, we have concluded that postoperative regular physical exercise, low fat and restricted calorie intake were very important to keep the late patent grafts in long-term follow up period after coronary bypass surgery.     

Osseous xanthomatosis and a pathologic fracture in a patient with hyperlipidemia. A case report

Osseous xanthomatosis and a pathologic fracture of the femoral neck associated with hyperlipoproteinemia occurred in a 48-year-old woman. Widely distributed skeletal lesions suggested a primary neoplasm such as malignant lymphoma or multiple myeloma; however, needle aspiration cytology of the fracture site, cutaneous manifestations, and abnormally high concentrations of lipoproteins established a diagnosis of intraosseous xanthomatosis associated with hyperlipidemia. Histologically, the excised femoral head showed a dense aggregate of lipid-laden macrophages and depletion of normal bone trabeculae. The hyperlipidemia is classified as Type IIb hyperlipoproteinemia.     

Physiological significance of plasma free and conjugated dopamine in healthy volunteers--with special reference to sympathetic nerve activity

In order to elucidate the physiological significance of plasma dopamine, blood pressure, pulse rate (PR), plasma concentrations of free or conjugated dopamine (free or conjugated pDA), noradrenaline (pNA) and adrenaline (pAd) were measured in 9 healthy volunteers. Blood sampling for the measurements was performed at a basal condition maintaining a supine position for 60 minutes, after twenty minutes 60 degrees head-up tilt (tilt) and an intravenous infusion of 1000 ml 0.9% saline for 2 hours. Following tilt, mean values in diastolic and mean blood pressure, PR, pNA and pAd were significantly increased, while free, conjugated and total pDA were decreased. On the other hand, saline infusion yielded significant decreases in hematocrit, pNA, free, conjugated and total pDA, but blood pressure, PR and pAd remained at the same level. Free/conjugated pDA ratio did not change during tilt or saline infusion. The basal value of free, conjugated or total pDA did not significantly correlate with blood pressure, PR, pNA or pAd, respectively. Furthermore, no significant correlations between the changes in pDAs and hemodynamic parameters, pNA or pAd by tilt or saline infusion were observed. From these results, it was suggested that plasma free or conjugated dopamine in physiological conditions may not be released from sympathetic nerve endings or adrenomedullary glands. Further investigations are needed to clarify the physiological significance of plasma dopamine in humans.     

Mechanisms underlying the enhanced elevation of IL-1beta and TNF-alpha mRNA levels following endotoxin challenge in rat alveolar macrophages cultured with low-Mg2+ medium.

We have previously shown that interleukin (IL)-1beta and tumour necrosis factor (TNF)-alpha mRNA levels in rat alveolar macrophages are increased in by endotoxin (lipopolysaccharide; LPS)- stimulation and further enhanced by culturing with low-Mg2+ medium. We have now investigated the mechanisms of underlying this enhancement by using some specific signal transduction inhibitors. The enhanced elevation of both mRNAs levels was suppressed by pretreatment with TMB-8 (which inhibits calcium release from the endoplasmic reticulum) or dexamethasone (which inhibits nuclear factor [NF]-kappaB and activator protein [AP]-1), but not with verapamil or nifedipine (which inhibits calcium channels). The enhancment of IL-1beta, but not TNF-alpha mRNA levels, was suppressed by pretreatment with W-7 (which inhibits calmodulin), whereas the enhancement of TNF-alpha mRNA levels was suppressed by pretreatment with U73122 (which inhibits phospholipase C). Curcumin (an inhibitor of AP-1), suppressed the increases in both mRNAs induced by low-Mg2+ medium alone, but had no suppressive effect on the levels of either mRNA after LPS-stimulation in low-Mg2+ medium. Pyrrolidine dithiocarbamate (an inhibitor of NF-kappaB) prevented the elevation of TNF-alpha mRNA levels induced by low-Mg2+ medium without LPS-stimulation, but had no suppressive effect on IL-1beta mRNA levels. From these results, we conclude that the enhanced elevation of IL-1beta and TNF-alpha mRNA levels seen in LPS-stimulated alveolar macrophages in low-Mg2+ medium occurs partly via the same, and partly via different, signaling pathways.     

Promoter methylation and protein expression of the E-cadherin gene in the clinicopathologic assessment of adenoid cystic carcinoma.

Adenoid cystic carcinoma, a relatively uncommon tumor of salivary glands, is characterized by a prolonged clinical course and a fatal outcome. The molecular events underlying their progression are unknown. In this study, we examined the methylation status of E-cadherin gene and its protein expression in 23 cases of adenoid cystic carcinoma and correlated the results with the clinicopathologic factors to determine its role in these tumors. We also analyzed the effect of 5-azacytidine on the re-expression in a methylated cell line of adenoid cystic carcinoma for this gene. In our study, E-cadherin immunoreactivity, although heterogeneous, showed a progressive reduction with high histological grade and in metastatic and recurrent lesions. Promoter methylation was detected in 16 of 23 cases (70%), but there was no correlation with the histological grade or patient prognosis. Microdissection of immuno-negative cells in heterogeneous tumors showed positive methlyation. In the cell line from salivary adenoid cystic carcinoma with methylated E-cadherin, 5-azacytidine restored the E-cadherin expression. Our results indicate that: (1) E-cadherin gene promoter is frequently methylated in adenoid cystic carcinoma, leading to reduced E-cadherin expression, (2) variable E-cadherin expression might result from the intratumoral heterogeneity, and (3) increased extent of methylated areas may be associated with progression and advancement of the disease.