TASK DEFINITION: In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
PROBLEM: Context: We developed an algorithm that prospectively defines when to excise the neurovascular bundles during radical retropubic prostatectomy with the goal of maximizing the performance of nerve sparing procedures while minimizing positive surgical margins.', 'From January 1 to December 31, 2000 a single surgeon performed 272 radical retropubic prostatectomies and 263 were performed from January 1 to December 31, 2001. A single pathologist analyzed all specimens with positive margins. There were no prospectively defined criteria to guide decisions regarding excision of the neurovascular bundles in the 2000 study cohort. Gleason score, percent tumor volume and perineural invasion were independently analyzed in the biopsy specimens according to the site of origin (right versus left side) for the 2001 group only. The ipsilateral neurovascular bundle was excised for Gleason 6 or less tumors when there were 50% or greater tumor volume in the biopsy specimen and perineural invasion, for Gleason 7 tumors when there was 30% or greater tumor volume, or perineural invasion and for Gleason 8 to 10 tumors when there was 10% or greater tumor volume, or perineural invasion.', 'There were no statistically significant differences between the 2000 and 2001 groups in regard to preoperative prostate specific antigen, clinical and pathological stage, biopsy Gleason score and percent tumor volume in the surgical specimen. There was a statistically significant decrease in the incidence of positive margins between the 2000 and 2001 groups (14% versus 8%, p = 0.027). The lower positive margin rate was not achieved because of a tendency to excise more neurovascular bundles since a significantly greater percent of neurovascular bundles was preserved in the 2001 group. The sensitivity, specificity, positive and negative predictive values, and accuracy of our algorithm were 18%, 93%, 28%, 89% and 84%, respectively. In sides of the prostate with extraprostatic extension ipsilateral wide excision of the neurovascular bundle was associated with positive margins in 33% of cases compared with 22% when the neurovascular bundle was preserved (p = 0.42).\Question: Does the New York University nerve sparing algorithm decrease the rate of positive surgical margins following radical retropubic prostatectomy?

SOLUTION: The New York University nerve sparing algorithm prospectively defines when to excise the neurovascular bundle based on Gleason score, perineural invasion and tumor volume in the biopsy specimen. Use of this algorithm decreases positive surgical margin rates, while significantly increasing the preservation of neurovascular bundles.

PROBLEM: Context: Vitamin A plays a major role in lipid metabolism. Previously, we reported that chronic vitamin A feeding (129 mg/kg) for two months normalized the abnormally high plasma HDL-cholesterol (HDL-C) levels in hypercholesterolemic obese rats by upregulating the hepatic scavenger receptor class B type 1 (SR-BI) expression. In this report, we hypothesize that the administration of a dose less than 129 mg of vitamin A/kg would also be effective in lowering the plasma HDL-C levels in these rats.', 'Changes in the activity and expression of proteins related to RCT were analyzed together with blood parameters in five-month-old male lean and obese rats supplemented with 2.6 (control group), 26, 52 and 129 mg of vitamin A/kg as retinyl palmitate for 20 weeks.', 'Vitamin A supplementation in the obese rats decreased the plasma HDL-C levels with a concomitant increase in the hepatic SR-BI expression and lipase activity compared to that observed in the control diet-fed obese rats treated with 2.6 mg of vitamin A/kg diet. Furthermore, vitamin A supplementation at doses of 52 and 129 mg/kg diet reduced the plasma lecithin cholesterol acyltransferase activity and increased the hepatic ATP-binding cassette transporter protein A1 expression in the obese rats. Interestingly, most of these changes were not observed in the lean rats fed a vitamin A-enriched diet.\Question: Does vitamin A-enriched diet modulate reverse cholesterol transport in hypercholesterolemic obese rats of the WNIN/Ob strain?

SOLUTION: Chronic feeding of a vitamin A-enriched diet in hypercholesterolemic obese rats normalizes the plasma HDL-C level and presumably improves RCT, with an effective dose of 52 mg/kg diet. Further studies should focus on the pharmacological potential of vitamin A supplementation to correct an abnormal human obesity-associated lipoprotein metabolism.

PROBLEM: Context: Gastrin and pepsinogens reflect the functional state of the gastric mucosa.', 'To evaluate whether serum gastrin and pepsinogens correlate with the different grades of severity of gastro-oesophageal reflux disease (GERD).', "In all, 388 patients with heartburn not taking any form of acid suppressive therapy were matched-controlled for age and gender and sub-classified into four groups: group 1 non-erosive reflux disease (NERD); group 2, erosive reflux disease (ERD) Los Angeles (LA) A and B, group 3, ERD LA C and D; group 4 Barrett's oesophagus (BO). Fasting serum was analysed for gastrin 17, pepsinogen I, pepsinogen II und Helicobacter pylori using specific EIA tests (GastroPanel; Biohit, Plc).", 'Kruskal-Wallis test and analysis of variance.', 'There was a significant difference among the four groups with respect for pepsinogen I, but not for pepsinogen II, the pepsinogen I pepsinogen II ratio, H. pylori serology and gastrin levels. Pepsinogen I was the lowest in NERD and the highest in BO (median 91.6, mean +/- standard deviation 106.2 +/- 51.6 vs. median 114.7, mean +/- standard deviation 130.4 +/- 70.6; P = 0.046). Pepsinogen I levels were higher in H. pylori positive subjects. After adjusting for H. pylori status, the differences in pepsinogen I across patient groups were no longer statistically significant (P = 0.298).\Question: Do serum gastrin and pepsinogens correlate with the different grades of severity of gastro-oesophageal reflux disease : a matched case-control study?

SOLUTION:
Serum gastrin and pepsinogen I and II do not correlate with the different grades of severity of GERD. The non-invasive GastroPanel is not useful for the differentiation of the various forms of GERD.