Site percolation and random walks on d-dimensional Kagome lattices

The site percolation problem is studied on d-dimensional generalisations of the Kagome' lattice. These lattices are isotropic and have the same coordination number q as the hyper-cubic lattices in d dimensions, namely q=2d. The site percolation thresholds are calculated numerically for d= 3, 4, 5, and 6. The scaling of these thresholds as a function of dimension d, or alternatively q, is different than for hypercubic lattices: p_c ~ 2/q instead of p_c ~ 1/(q-1). The latter is the Bethe approximation, which is usually assumed to hold for all lattices in high dimensions. A series expansion is calculated, in order to understand the different behaviour of the Kagome' lattice. The return probability of a random walker on these lattices is also shown to scale as 2/q. For bond percolation on d-dimensional diamond lattices these results imply p_c ~ 1/(q-1).Comment: 11 pages, LaTeX, 8 figures (EPS format), submitted to J. Phys.

Les Sarcosporidies des petits ruminants au Sénégal

Les Sarcosporidies des petits ruminants rencontrées au Sénégal ont été étudiées. Une prévalence de 82 p. 100 d'infestations à S. ovicanis chez le mouton et de 88 p. 100 à S. capracanis chez la chèvre a été trouvée. Pour S. capracanis une étude est faite au microscope électronique. L'importance de la sarcosporidose dans la pathologie des petits ruminants est discuté

Prognostic value of bcl-2 expression in invasive breast cancer.

Expression of the bcl-2 proto-oncogene was studied immunohistochemically in 251 invasive ductal breast carcinomas (median follow-up time 91 months, range 24-186 months) and the results were correlated with clinicopathological data and prognostic variables. Sixty-three (25%) tumours were scored bcl-2 negative and 188 (75%) tumours were bcl-2 positive. No relationship could be observed between bcl-2 status and tumour grade, pTNM staging or menopausal status. A strong positive relationship was demonstrated between bcl-2 immunoreactivity and oestrogen receptor status (P < 0.001) and progesterone receptor status (P < 0.001). No prognostic value was demonstrated for bcl-2 expression on disease-free survival and overall survival in axillary node-negative breast cancer patients. However, in axillary node-positive breast cancer patients multivariate analysis demonstrated absence of bcl-2 expression to be independently related to shortened disease-free survival (P = 0.003) and shortened overall survival (P < 0.001). Our results suggest a potential important role for bcl-2 expression as a modulator of response to adjuvant therapy in breast cancer

Quantification and prognostic relevance of angiogenic parameters in invasive cervical cancer.

Tumour stromal neovascularization was investigated in 114 invasive and 20 in situ carcinomas of the uterine cervix by staining representative sections with the specific endothelial marker anti CD31 (clone JC/70A, isotope IgG1). A digital image analyser was used to measure the immunoreactivity. The following parameters were determined in the 'hot spots': vessel counts, vessel perimeter and endothelial stained area (expressed per mm2). The results were correlated with clinical and histopathological data. There was no significant relationship between the histopathological findings (tumour histology, tumour differentiation, FIGO stage, presence of lymph node metastasis or lymphovascular space involvement) and the median vessel count. In a univariate analysis all angiogenesis parameters had prognostic value: a higher vascularity was associated with worse prognosis (P < 0.05). Multiple regression analysis showed that vascular permeation (P < 0.001) and the median vessel count (P = 0.005) were the most important prognostic indicators. In the future these criteria may be used for selection of patients for anti-angiogenesis therapy

Vitamin C as well as β-carotene attenuates experimental liver fibrosis after intoxication with carbon tetrachloride in rats

The therapeutic effects of vitamin C and &#946;-carotene on chronic liver diseases have not yet been fully demonstrated and their application as dietary intakes or supplements lacks strong experimental backing. We aimed at investigating the therapeutic efficacy of these vitamins on hepatic fibrogenesis caused by carbon tetrachloride (CCl4)-intoxication in rats. Four groups of albino rats were used: group 1 (control) received only saline, whereas groups 2-4 were injected intraperitoneally with 0.5 mL/kg body weight CCl4 every 3 days plus pentobarbital (0.3 mg/L) in drinking water for 10 weeks; after which CCl4 and pentobarbital were stopped and the animals in group 2 were allowed to rest, while those in groups 3 and 4 were treated with intramuscular injections (100 mg/kg/day) of vitamins C and &#946;-carotene, respectively, for further 2 weeks. CCl4 plus pentobarbital resulted in well established fibrosis associated with notable steatosis and ballooning. Treatment with vitamin C or &#946;-carotene modulated CCl4-induced liver pathology, as reflected by significantly lower histological scores (p&lt;0.05). Vitamin C intervention was also associated with significantly lower levels of liver enzymes, unlike &#946;-carotene. We conclude that compared to &#946;-carotene, vitamin C significantly ameliorated both biochemical and histological changes in CCl4-induced liver disease and that both vitamins separately attenuated liver fibrosis.Keywords: Albino rats, liver enzymes, hepatic fibrosis, histological scores, CCl

Cellular infiltrates and injury evaluation in a rat model of warm pulmonary ischemia–reperfusion

INTRODUCTION: Beside lung transplantation, cardiopulmonary bypass, isolated lung perfusion and sleeve resection result in serious pulmonary ischemia–reperfusion injury, clinically known as acute respiratory distress syndrome. Very little is known about cells infiltrating the lung during ischemia–reperfusion. Therefore, a model of warm ischemia–reperfusion injury was applied to differentiate cellular infiltrates and to quantify tissue damage. METHODS: Fifty rats were randomized into eight groups. Five groups underwent warm ischemia for 60 min followed by 30 min and 1–4 hours of warm reperfusion. An additional group was flushed with the use of isolated lung perfusion after 4 hours of reperfusion. One of two sham groups was also flushed. Neutrophils and oedema were investigated by using samples processed with hematoxylin/eosin stain at a magnification of ×500. Immunohistochemistry with antibody ED-1 (magnification ×250) and antibody 1F4 (magnification ×400) was applied to visualize macrophages and T cells. TdT-mediated dUTP nick end labelling was used for detecting apoptosis. Statistical significance was accepted at P < 0.05. RESULTS: Neutrophils were increased after 30 min until 4 hours of reperfusion as well as after flushing. A doubling in number of macrophages and a fourfold increase in T cells were observed after 30 min until 1 and 2 hours of reperfusion, respectively. Apoptosis with significant oedema in the absence of necrosis was seen after 30 min to 4 hours of reperfusion. CONCLUSIONS: After warm ischemia–reperfusion a significant increase in infiltration of neutrophils, T cells and macrophages was observed. This study showed apoptosis with serious oedema in the absence of necrosis after all periods of reperfusion

Paclitaxel for malignant pleural mesothelioma: a phase II study of the EORTC Lung Cancer Cooperative Group.

The EORTC Lung Cancer Cooperative Group undertook a phase II study of paclitaxel in 25 chemotherapy-naive patients with malignant pleural mesothelioma. Paclitaxel was given intravenously at a dose of 200 mg m-2 as a 3 h infusion every 3 weeks, after standard premedication with corticosteroids and antihistamines. This regimen was well tolerated, with < 4% of cycles resulting in severe toxicity. No major objective responses were observed and ten patients had stable disease. Median survival time was 39 weeks and the 1 year survival rate was 30%. In conclusion, paclitaxel at the dose and schedule investigated in this trial had no major activity in the treatment of malignant pleural mesothelioma

Microvessel quantification in primary colorectal carcinoma: an immunohistochemical study.

The vascularisation of human primary colorectal carcinomas was studied immunohistochemically using the endothelial cell markers CD31 and factor VIII-related antigen. Tumour sections were systematically scanned at a magnification of x 100 to find areas of intense neovascularisation. Microvessel counts within these vascular 'hotspots' were performed at magnification x 250. Regions in which tumour cords were surrounded by a collagen IV-positive basement membrane were compared with those in which this was absent and with normal mucosa. CD31 appeared to be a more sensitive marker for endothelial cells than factor VIII-related antigen (mean 185 +/- 59 and 120 +/- 38 microvessels mm-2). Within individual tumour sections microvessel counts in vascular hotspots with highest vessel density correlated significantly with microvessel counts in vascular hotspots with second highest vessel density (P < 0.01). Microvessel counts in tumour areas where collagen IV-positive basement membrane were absent exceeded those in areas where it was present (factor of 1.7) and those in normal mucosa (factor of 1.6). The differences in vessel density between individual tumours and the low variability in vessel density within individual tumours using this quantification technique allow us to investigate the prognostic value of vessel density in areas of intense neovascularisation in human primary colorectal carcinomas