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.

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?
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.

Context: To examine peripheral nerve stimulation (PNS) thresholds for normal human subjects in magnetic resonance imaging (MRI) gradient coils, and determine if observed thresholds could be predicted based on gross physiologic measurements.', 'PNS thresholds for 21 healthy normal subjects were measured using a whole-body gradient coil. Subjects were exposed to a trapezoidal echo-planar imaging (EPI) gradient waveform and the total change in gradient strength (DeltaG) required to cause PNS as a function of the duration of the gradient switching time (tau) were measured. Correlation coefficients and corresponding P values were calculated for the PNS threshold measurements against simple physiologic measurements taken of the subjects, including weight, height, girth, and average body fat percentage, in order to determine if there were any easily observable dependencies.', 'No convincing correlations between threshold parameters and gross physiologic measurements were observed.\Question: Do simple anatomical measurements correlate significantly to individual peripheral nerve stimulation thresholds as measured in MRI gradient coils?
These results suggest it is unlikely that a simple physiologic measurement of subject anatomy can be used to guide the operation of MRI scanners in a subject-specific manner in order to increase gradient system performance while avoiding PNS.

Context: To assess the incidence of retained products of conception (RPOC) in relation to transvaginal ultrasound performed after first-trimester uterine evacuation.', 'This was a prospective randomized study involving 809 women undergoing first-trimester uterine evacuation. The study group included 404 women in whom transvaginal sonography was performed at the end of the surgical procedure and the control group contained 405 women who did not undergo ultrasound examination. Initially, in the study group, recurettage was immediately performed if the endometrium appeared irregular but latterly only if endometrial thickness was > or = 8 mm. The patients were followed up by gynecological and ultrasound examinations 5-8 days following the surgical procedure.', 'The total complication rate was 4.3%. RPOC presented in three women in the study group (0.7%) and in 15 women in the control group (3.7%, P < 0.05). Vaginal bleeding requiring hospitalization occurred in two women in the study group (0.5%) vs. seven in the control group (1.7%, P = 0.2). Endometritis was diagnosed in one woman in the study group (0.2%) vs. six in the control group (1.5%) and uterine perforation occurred in one woman in the control group vs. none in the study group. There were no cases of RPOC in women who had an endometrial thickness of < 8 mm as demonstrated by ultrasound at the end of the surgical procedure.\Question: Does transvaginal ultrasound after first-trimester uterine evacuation reduce the incidence of retained products of conception?
Transvaginal sonography immediately following first-trimester uterine evacuation may reduce the incidence of RPOC and the total complication rate. When the endometrial thickness is > or = 8 mm at the end of suction curettage, an attempt at re-evacuation of the uterine cavity is indicated.