Blood supply of the sinus node artery in beagle dogs

Summary Postmortem coronary angiography was performed in 20 beagles and 15 mongrels, and the origin and distribution of the sinus node arteries (SNAs) were subsequently investigated using soft X-ray radiography, the tissue clearing method, and histological examination. In 19 of 20 beagles, the SNAs consisted of a single atrial branch originating from the right coronary artery, and the distribution pattern of the atrial branch seemed to be uniform. In contrast, the following three different patterns were recognized in the atrial branches forming the SNAs of mongrels: (1) distribution by two atrial branches, i.e., one originating from the right coronary artery and the other from the left circumflex artery, (2) dual distribution by two atrial branches originating from the right coronary artery, and (3) distribution by a single atrial branch originating from the right coronary artery or from the left circumflex artery. In 26 of the 30 dogs which were histologically examined, the SNAs ran outside of the sinus node and were not centrally located. In the beagles, the proximal atrial branch from the right coronary artery reached the atrioventricuolar node area and supplied blood to the atrioventricular node together with the arterial branches derived from the anterior septal artery and posterior septal artery. In addition, the arterial branch of the SNAs reached the atrioventricular junction area. These findings should contribute to clinical, pharmacological, and pathological studies of the cardiovascular system, including studies on cardiac arrhythmias in beagles.     

Lysophosphatidic acid transactivates both c-Met and epidermal growth factor receptor, and induces cyclooxygenase-2 expression in human colon cancer LoVo cells

AIM: To examine whether lysophosphatidic acid (LPA) induces phosphorylation of c-Met and epidermal growth factor receptor (EGFR), both of which have been proposed as prognostic markers of colorectal cancer, and whether LPA induces cyclooxygenase-2 (COX-2) expression in human colon cancer cells. METHODS: Using a human colon cancer cell line, LoVo cells, we performed immunoprecipitation analysis, followed by Western blot analysis. We also examined whether LPA induced COX-2 expression, by Western blot analysis. RESULTS: Immunoprecipitation analysis revealed that 10 umol/L LPA induced tyrosine phosphorylation of c-Met and EGFR in LoVo cells within a few minutes. We found that c-Met tyrosine phosphorylation induced by LPA was not attenuated by pertussis toxin or a matrix metalloproteinase inhibitor, in marked contrast to the results for EGFR. In addition, 0.2-40 umol/L LPA induced COX-2 expression in a dose-dependent manner. CONCLUSION: Our results suggest that LPA acts upstream of various receptor tyrosine kinases (RTKs) and COX-2, and thus may act as a potent stimulator of colorectal cancer.     

Aggressive surgical resection for hepatocellular carcinoma with tumor thrombus extending to inferior vena cava and synchronous pulmonary metastasis

We describe a 66-year-old man having hepatocellular carcinoma with tumor thrombus extending into the inferior vena cava and synchronous pulmonary metastasis. He was referred to Chiba University Hospital on May, 2000, complaining of emaciation. Radiological findings showed a huge hepatocellular carcinoma in the entire right lobe and tumor thrombus extended into the intrapericardial inferior vena cava. He also had a solitary pulmonary metastasis in the left pulmonary lobe (stage IVB). Right hemihepatomy was performed under total hepatic vascular exclusion without cardiopulmonary bypass, and tumor thrombus was completely removed. Thoracoscopic wedge resection of pulmonary metastasis was also performed. The patient had an uneventful postoperative course. Histopathological examination revealed that the tumor was moderately differentiated hepatocellular carcinoma The patient is still alive after 26 months with pulmonary recurrence, but without hepatic recurrence. To our knowledge, there has been no reported case of resection for both hepatocellular carcinoma invading the inferior vena cava and synchronous pulmonary metastasis. In conclusion, aggressive surgical resection for advanced hepatocellular carcinoma concomitant with pulmonary resection may bring about better prognosis in highly selected patients.     

Effects of 17beta-estradiol, nonylphenol, and bisphenol-A on developing Xenopus laevis embryos

Many chemicals released into the environment have the capacity to disrupt the normal development of aquatic animals. We investigated the influence of nonylphenol (NP), bisphenol-A (BPA), and 17beta-estradiol (E2) on developing Xenopus laevis embryos, as a model animal in the aquatic environment. Embryos were exposed to eight different concentrations of NP, BPA or E2 between 3 and 96 h post-fertilization (p.f.). Short body length, microcephaly, flexure, edema, and abnormal gut coiling were induced by 20 microM NP, BPA or 10 microM E2 by 96 h p.f. To clarify sensitive stages to these compounds, embryos were exposed to chemicals for 45 or 48 h starting at different developmental stages and experiments were terminated 96 h p.f. BPA and NP induced abnormalities in developing X. laevis, though the sensitive stages of embryos to these chemicals are different, BPA affecting earlier stages and NP affecting at later stages. To analyze the functional mechanisms of BPA and NP in induction of morphological changes, we adapted a DNA array technology and identified 6 X. laevis genes, XIRG, alpha skeletal tropomyosin, cyclin G1, HGF, troponin C2, and ribosomal protein L9. These findings may provide important clues to elucidate common mechanisms underlying teratogenic effects of these chemicals.     

Regional patterns of birthweights in Papua New Guinea in relation to diet,environment and socio-economic factors

Regional differences in mean birthweight in rural Papua New Guinea (PNG) and the importance of differences in family diet and maternal education and socio-economic status on such patterns were explored using birthweight data collected by the 1982/83 PNG National Nutrition Survey. A total of 6137 birthweight measurements from 85 PNG districts were available, representing 22% of all children included in the survey. The nature of possible selection biases are assessed and their implications discussed. Hierarchical Bayesian spatial models based on conditional autoregressive (CAR) priors were used to model spatial patterns in birthweights and their relation to different sets of covariates. Birthweights were found to exhibit striking geographical differences. Children from the central PNG highlands and from affluent lowland areas had the highest birthweights, while they were lowest in the (largely lowland) Sepik, Western, Madang and Milne Bay Provinces and in remote highland fringe areas. Maternal education, socio-economic status and diet were all important predictors, but only differences in family diet were correlated with the observed spatial patterns. The results of the present study highlight the importance of nutrition and socio-economic status in explaining differences in birthweights in PNG. Besides improving maternal health, interventions for improving birthweights in PNG should therefore aim at strengthening the economic base of rural populations and promote the cultivation and consumption of high quality foods.     

Antegrade selective cerebral perfusion with mild hypothermic systemic circulatory arrest during thoracic aortic surgery

Objective Antegrade selective cerebral perfusion (ASCP) and retrograde cerebral perfusion (RCP) have proven to be reliable methods of brain protection during aortic surgery. These techniques are usually accompanied by systemic circulatory arrest with moderate hypothermia (24–28°C) or deep hypothermia (18–24°C). However, hypothermia can lead to various problems. The present study therefore reports results for thoracic aorta replacement using ASCP with mild hypothermic systemic arrest (28–32°C).

Design Between 1995 and 2003, 68 consecutive patients underwent repair of the ascending aorta and/or aortic arch. Mild hypothermic ASCP was utilized in 31 cases, moderate hypothermic ASCP in 20, and deep hypothermic RCP in 17. Various parameters were compared between the mild hypothermic ASCP, moderate hypothermic ASCP, and RCP.

Results Hospital mortality was 10.3%, with no significant differences observed between any groups. Permanent neurological dysfunction was 8.8%, and no significant differences were observed between any groups. Mild hypothermic ASCP displayed significantly decreased transfusion volume, intubation time, and ICU stay.

Conclusions Use of ASCP with mild hypothermic systemic circulatory arrest during aortic surgery resulted in acceptable hospital mortality and neurological outcomes. ASCP with mild hypothermic arrest allows decreased transfusion volume and reduced duration of intubation and ICU stay.