Hyperdynamic circulation of cirrhotic rats: role of substance P and its relationship to nitric oxide

BACKGROUND: It has been suggested that excessive formation of nitric oxide (NO) is responsible for the hyperdynamic circulation observed in portal hypertension. Substance P is a neuropeptide partly cleared by the liver and causes vasodilatation through the activation of the endothelial NO pathway. However, there are no previously published data concerning the plasma level of substance P in cirrhotic rats and its relationship to NO. METHODS: Plasma concentrations of substance P and nitrate/nitrite (an index of NO production) were determined in control rats and cirrhotic rats with or without ascites using an enzyme-linked immununosorbent assay and a colorimetric assay, respectively. In addition, systemic and portal hemodynamics were evaluated by a thermodilution technique and catheterization. RESULTS: Cirrhotic rats with and without ascites had a lower systemic vascular resistance (2.6 +/- 0.2 and 3.9 +/- 0.4 mmHg ml(-1) x min x 100 g body weight, respectively) and higher portal pressure (14.6 +/- 0.6 and 11.3 +/- 1.8 mmHg) than control rats (6.5 +/- 0.3 mmHg x ml(-1) x min x 100 g BW and 6.8 +/- 0.2 mmHg, respectively, P < 0.05), and cirrhotic rats with ascites had the lowest systemic vascular resistance. Plasma levels of nitrate/nitrite progressively increased in relation to the severity of liver dysfunction (control rats, 2.7 +/- 0.5 nmol/ml; cirrhotic rats without ascites, 5.6 +/- 1.3 nmol/ml; cirrhotic rats with ascites, 8.3 +/- 2.2 nmol/ml; P < 0.05). Cirrhotic rats with ascites displayed higher plasma values of substance P (57.7 +/- 5.9 pg/ml) than cirrhotic rats without ascites (37.9 +/- 3.1 pg/ml, P < 0.05) and control rats (30.1 +/- 1.0 pg/ml, P < 0.05). There was no significant difference in plasma substance P values between control rats and cirrhotic rats without ascites (P > 0.05). No correlation was found between plasma levels of substance P and nitrate/nitrite (r = 0.318, P > 0.05). CONCLUSIONS: Excessive formation of NO may be responsible, at least partly, for the hemodynamic derangements in cirrhosis. Although substance P may not participate in the initiation of a hyperdynamic circulation in cirrhosis, it may contribute to the maintenance of the hyperdynamic circulation observed in cirrhotic rats with ascites.     

Judgments of social justice: Compromises between equality and efficiency.

Political economists agree that a trade-off exists between equality and efficiency. Using a hypothetical society paradigm, the mean income (representing efficiency) and income variability (representing equality) of distributions of wealth and the correlation between wealth and effort within a society were manipulated. Ss made all pairwise comparisons of distributions within societies of differing meritocracy. A "maximin" principle best described trade-off resolution strategies when effort and outcome were weakly linked: People maximized the minimum standard of living within a society. A compromise principle best described preferences when income was tightly linked to effort: People rejected distributions in which some citizens fell below the "poverty line" but maximized efficiency above this constraint. Ideological polarization was pronounced under moderate meritocracy; here liberals could focus on the role of chance and conservatives on the role of effort and ability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retinopathy of prematurity in Frederiksborg County 1988-1990. A prospective investigation, an update

A report is given of retinopathy of prematurity findings in a Danish county (pop. 342,000) for birth years 1988-90. Out of 12,116 liveborn infants 200 were followed with eye controls during (at least) the first 3 months. In 135 gestational age and/or birth weight were below 32 weeks/1750 g. Twenty-five had ROP stage 1-2 with uneventful regression. Out of 5 with at least stage 3 ROP 2 had spontaneous regression. Three had cryotherapy; two acquired unilateral blindness, one myopia of prematurity. As part of an ongoing prospective investigation the visual results denote progress as compared to the serious results from the preceding 6 years (6 blind children). For 1982-90 the pooled ROP blindness rate amounted to 18.7/100,000 liveborn, a frequency only to be surpassed by the neighbouring Copenhagen area. Considering correct timing of cryotherapy close observation of small premature infants is recommended. At present our screening limits are 32 weeks gestational age/1750 g birth weight.     

The survival and growth of ovine afferent lymph dendritic cells in culture depends on tumour necrosis factor-alpha and is enhanced by granulocyte-macrophage colony-stimulating factor but inhibited by interferon-gamma

An in vitro culture system is described which allows an analysis of the signals responsible for the survival, growth and functional maturation of afferent lymph dendritic cells (ALDC), a subpopulation of migrating dermal dendritic cells involved in antigen carriage and presentation to T-cells. Purified ALDC survived and grew for up to 30 days in lymph node conditioned medium and survived 14 days in recombinant ovine (rov) TNF-alpha whereas none were detected after 24 h in rov GM-CSF, rov IFN-gamma or rh M-CSF. However, when rov GM-CSF was added to cultures along with rov TNF-alpha, increased numbers of ALDC compared with input numbers (growth) were recorded on Days 14 and 21. In contrast, when 50-200 units ml-1 of rov IFN-gamma were added to cultures of ALDC along with TNF-alpha or rov TNF-alpha plus rov GM-CSF, cell survival and growth was inhibited. Antibody blocking studies confirmed the cytokine specificity of these effects. ALDC cultured in rov TNF-alpha or rov TNF-alpha plus rov GM-CSF retained MHC Class-II and ov CD-1 antigen expression and accessory function for autologous ov CD-4 T-cell proliferation, although at reduced levels compared with freshly isolated cells. Neither fresh nor cultured ALDC expressed coagulation factor XIIIa.     

Precision edge contrast and orientation estimation

The contrast and orientation estimation accuracy of several edge operators that have been proposed in the literature is examined both for the noiseless case and in the presence of additive Gaussian noise. The test image is an ideal step edge that has been sampled with a square-aperture grid. The effects of subpixel translations and rotations of the edge on the performance of the operators are studied. It is shown that the effect of subpixel translations of an edge can generate more error than moderate noise levels. Methods with improved results are presented for Sobel angle estimates and the Nevatia-Babu operator, and theoretical noise performance evaluations are also provided. An edge operator based on two-dimensional spatial moments is presented. All methods are compared according to worst-case and RMS error in an ideal noiseless situation and RMS error under various noise levels