Given a passage with a context and an answer, 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.
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Question: Context: 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).
Answer: There is evidence that the three-dimensional structure of PEGT/PBT-block-copolymer (pore size structure) influences neovascularization. The porous structures of copolymer matrices with adequate interconnection of pores (pore sizes of 75-212 and 250-300 microm) are characterized by faster ingrowth of vascular tissue.

Answer: Does analysis of neovascularization of PEGT/PBT-copolymer dermis substitute in balb/c-mice?

Question: Context: The goals of the current study were to examine the incidence and severity of toxicity resulting from dexamethasone and prednisone during induction therapy for children with precursor B-cell acute lymphoblastic leukemia (ALL) and to determine whether the addition of daunomycin affected toxicity.', 'Medical records of patients with precursor B-cell ALL from January 1996 through June 2000 were reviewed retrospectively for toxicity during the 4-week induction phase and the 2 weeks after the induction phase.', 'One hundred seventy-six patients age < 14 years were diagnosed with precursor B-cell ALL from January 1996 through June 2000. Of the 156 evaluable patients, 106 were treated with prednisone and 50 with dexamethasone. Fifty-two patients received steroids, L-asparaginase, and vincristine, whereas 104 high-risk patients received daunomycin in addition to these 3 agents. The incidence of gastritis was significantly higher among patients receiving dexamethasone (P = 0.01); incidence rates of hyperglycemia, hypertension, and myopathy were similar for all treatment groups. Dexamethasone led to more weight gain than did prednisone (+11.9% vs. +5.4%; P = 0.002). Serious infections were observed in 27 (25.5%) and 18 (36%) patients receiving prednisone and dexamethasone, respectively (P < or = 0.2). Five patients, four of whom received prednisone and one of whom received dexamethasone, died of infection. The addition of daunomycin to treatment regimens increased overall toxicity (P < 0.01). When daunomycin was included in treatment regimens, toxicity was greater among patients receiving dexamethasone; in contrast, when daunomycin was not included, toxicity was equal for both treatment groups. Regardless of daunomycin use, there was no difference in the incidence of serious infection between the two groups. ALL treatment was not compromised by steroid-related toxicity in either group.
Answer: The addition of daunomycin led to a much larger increase in dexamethasone-related toxicity compared with the increase in prednisone-related toxicity. Although the use of daunomycin enhanced dexamethasone-related toxicity, this enhancement did not result in a higher mortality rate or the alteration of planned ALL therapy.

Answer: Is dexamethasone-associated toxicity during induction chemotherapy for childhood acute lymphoblastic leukemia augmented by concurrent use of daunomycin?

Question: Context: Low serum levels of vitamin D have been associated with depression in non-stroke subjects. Our aim was to examine the possible association between serum vitamin D levels and the development of post-stroke depression (PSD).', 'In total, 189 patients with acute ischaemic stroke were consecutively recruited. Serum levels of 25-hydroxyvitamin D [25(OH)D] were measured by competitive protein-binding assay within 24 h after admission. The 17-item Hamilton Depression Scale was used for screening for the existence of depressive symptoms at 1 month after stroke. Patients with a Hamilton Depression Scale score of 7 were given the Structured Clinical Interview of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, for diagnosis of PSD. Meanwhile, 100 healthy control subjects were also recruited and underwent measurement of 25(OH)D.', 'Fifty-five patients (29.1%) were diagnosed as having PSD at 1 month. Serum vitamin D levels within 24 h after admission were significantly lower in both non-PSD patients and PSD patients than in normal controls. PSD patients had significantly lower vitamin D than non-PSD patients. Serum vitamin D levels (37.1 and 64.1 nmol/l) were independently associated with the development of PSD (odds ratio 8.824, 95% confidence interval 2.011-38.720, P = 0.004, and odds ratio 0.127, 95% confidence interval 0.022-0.718, P = 0.020, respectively).
Answer: Serum vitamin D levels within 24 h after admission are found to be associated with PSD and may predict its development at 1 month post-stroke.

Answer:
Are low serum levels of vitamin D associated with post-stroke depression?