Given a passage, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Q: A fundamental prerequisite for using degradable synthetic biopolymers as composite skin substitutes is the ability to establish vascular tissue. PEGT/PBT block-copolymer matrices have previously been shown as a favorable dermal substitute. In this study, quantitative data on neovascularization of PEGT/PBT block-copolymer matrices are presented.', 'PEGT/PBT-block-copolymer discs of three different pore diameters (1: < 75 microm, 2: 75-212 microm, 3: 250-300 microm) were implanted into dorsal skinfold chambers of balb/c mice. Histological sections were evaluated 7, 14, and 21 days post implantation by light and scanning electron microscopy. Blood vessel analysis was performed by means of digital image analysis (n = 288) of hematoxylin/eosin stained sections within apical (AOF) and basal (BOF) observation fields of the matrices.', 'Twenty-one days after implantation the density of blood vessels within the BOF of the scaffolds with a pore size of 75-212 and 250-300 microm were 4.6 +/- 0.45 and 5.8 +/- 0.62 (mean +/- S.E.M.; blood vessel profiles (BVF)), respectively. In <75 microm scaffolds, smaller numbers of BVF were found (4.2 +/- 0.39). In contrast, the evaluation within the AOF revealed significantly higher numbers of BVF in 75-212 microm group (3.5 +/- 0.49) and 250-300 microm group (4.5 +/- 0.66) as compared to the < 75 microm group (2.3 +/- 0.48).

A: Does analysis of neovascularization of PEGT/PBT-copolymer dermis substitute in balb/c-mice?
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Q: To investigate the effects of copper on permeability and P-glycoprotein (P-gp) of Caco-2 cell monolayers.', 'The differentiated Caco-2 cell model was used in this study. Permeability of cell monolayers was reflected by monitoring transepithelial electrical resistance (TEER); distribution of tight junctional protein ZO-1 was measured by immunofluorescent staining; F actin was measured by fluorescence staining; and Activity of P-gp was reflected by changes of transcellular transport and accumulation of Rho-123 in Caco-2 cells.', "Apical treatment with copper (30 - 100 micromol/L, Hanks' buffered salt solution, up to 3 hours) induced a time- and concentration-dependent increase in permeability reflected by progressive decrease of TEER of Caco-2 cell monolayers, accompanied by deorganization of F actin, but without significant effects on tight junctional protein ZO-1; at a dose without any adverse effects on viability and permeability of Caco-2 monolayers, copper treatment (300 micromol/L, complete medium, 24 hours) decreased Papp(BL-->AP) from 7.37 +/- 0.20 x 10(-6) cm/s (controls) to (6.43 +/- 0.27) x 10(-6) cm/s, the increased Papp(AP-->BL) from (1.23 +/- 0.05) x 10(-7) cm/s (controls) to (3.41 +/- 0.08) x 10(-7) cm/s, and enhanced the intracellular Rho-123 from (0.31 +/- 0.01) nmol/filter (controls) to (0.50 +/- 0.03) nmol/filter.

A: Does [ Copper treatment alter the barrier functions of human intestinal Caco-2 cells ]?
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Q: To test the peripheral arterial vasodilation hypothesis of sodium retention in cirrhosis. This states that sodium retention is triggered by arterial underfilling and predicts that development of sodium retention will be associated with significant and related declines in indices of arterial filling that reverse when sodium retention resolves.', 'Longitudinal evaluation of a cohort of patients with alcoholic liver disease.', 'Eighteen men, 8 of whom were studied twice, 3 three times, 2 four times, and 5 five times (40 between-study comparisons). Between 23 studies, the patients were ascites-free (Group NN). Ascites spontaneously disappeared between seven studies (Group YN), appeared between six studies (Group NY), and remained present between four studies (Group YY). Between-study changes in blood volume, arterial blood pressure, cardiac output, systemic vascular resistance, left atrial volume, left ventricular diastolic diameter, aortic root diameter, aortic blood velocity, plasma norepinephrine and atrial natriuretic factor concentrations, plasma renin activity, and urinary sodium excretion were evaluated by paired t-tests. These changes were also compared among groups by analysis of variance. In addition, correlations among the changes were sought.', 'Systolic, diastolic, and mean arterial pressures, left ventricular diastolic diameter, aortic root diameter, stroke volume, cardiac output, plasma norepinephrine concentration, and systemic vascular resistance were unchanged between studies. Left atrial volume increased between studies in Group NY. Pulse pressure fell more in Group NY than in Groups NN and YN, principally as a result of a decline in systolic blood pressure. Plasma norepinephrine concentration, plasma renin activity, and blood volume rose more in Group NY than in Groups NN, YN, and YY. Changes in both systolic and pulse pressures were directly correlated with the change in sodium excretion but unrelated to the change in plasma norepinephrine concentration. Changes in plasma norepinephrine concentration and plasma renin activity were unrelated to changes in blood pressure, systemic vascular resistance, and urinary sodium excretion.

A:
Does arterial underfilling cause sodium retention in cirrhosis?
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