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.

[EX Q]: Context: Small studies suggest exogenous estrogen may improve vitamin D status, but the etiology is unclear because women who use hormones may make lifestyle choices that differentially affect vitamin D status.', 'Our objective was to investigate the association between use of hormonal contraception and 25-hydroxy-vitamin D (25(OH)D).', 'We used linear regression modeling of cross-sectional data to estimate percent change in season-adjusted serum 25(OH)D with estrogen use after adjustment for other factors.', 'At the enrollment clinic visit (2010-2012) into a cohort study of uterine fibroids, each subject provided a blood sample, had anthropomorphic variables and skin reflectance measured, and answered questionnaires on demographics, dietary and supplement intake, contraceptive use, reproductive and medical history, and behaviors.', 'A total of 1662 African American women, community volunteers, 23-34 years old, living in the Detroit, Michigan, area were included.', 'None.', 'Serum 25(OH)D was measured.', 'Serum 25(OH)D concentrations were low (70% <20 ng/ml). Current use of an estrogen-containing contraceptive was associated with a 20% (95% confidence interval: 14-27) increase in 25(OH)D after adjustment. There was no increase in 25(OH)D among participants who had used estrogen in the past, but were not current users, indicating that results were unlikely to be due to unmeasured confounding by factors related to contraceptive choice.
Answer: The increase in 25(OH)D with use of estrogen-containing contraceptives raise mechanistic questions regarding the biological pathways involved, and highlights the need for studies that examine possible endogenous estrogen effects on vitamin D.
[EX A]: Does use of Estrogen-Containing Contraception be Associated With Increased Concentrations of 25-Hydroxy Vitamin D?

[EX Q]: Context: To determine the role of herpes simplex virus-1 (HSV-1) glycoprotein K(gK) in corneal infection, neuroinvasion, and virus latency in trigeminal ganglia of mice.', 'The recombinant virus HSV-1 (McKrae) Delta gK (MKDelta gK) carrying a deletion of the gK gene was constructed by insertional/deletion mutagenesis and replaced by a gene cassette constitutively expressing the enhanced green fluorescence protein. The gK deletion of the MKDelta gK virus was rescued to produce the wild-type-like virus MKgK. Balb/c mice were infected ocularly with either virus, and the infection pattern in the eye, clinical disease progression, and establishment of viral latency was monitored.', 'Mice infected with the MKDelta gK strain produced in a gK complementing cell line did not exhibit clinical signs when compared with mice infected with the MKgK virus. Direct visualization of infected eyes revealed that the MKDelta gK virus was unable to spread in mouse corneas, while the MKgK rescued virus spread efficiently. Nineteen of 20 scarified and 5/12 unscarified mice infected with the MKgK virus produced infectious virus after coculture with permissive cells, while 0/20 scarified and 0/12 unscarified mice infected with the MKDelta gK virus produced infectious virus. HSV DNA was detected in trigeminal ganglia by PCR in 19/20 scarified and 9/12 unscarified mice inoculated with MKgK, while HSV DNA was detected in the trigeminal ganglia of 3/20 scarified and 0/12 unscarified mice inoculated with MKDelta gK.
Answer: The results show that HSV-1 gK is essential for efficient replication and spread in the corneal epithelium and trigeminal ganglia neuroinvasion in MKDelta gK inoculated mice.
[EX A]: Is the herpes simplex virus type 1 ( HSV-1 ) glycoprotein K ( gK ) essential for viral corneal spread and neuroinvasiveness?

[EX Q]: Context: To evaluate the anti-HIV-1 activity of the cyclotriazadisulfonamide CADA against primary isolates in vitro and the combination of CADA with approved anti-HIV drugs for potential synergy.', 'Peripheral blood mononuclear cells (PBMC) were treated with CADA and infected with 16 different clinical isolates. After 8 days of infection, the median inhibitory concentration (IC50) was calculated from the p24 viral antigen content in the supernatant. MT-4 cells were infected with HIV-1NL4.3 and then cultured with CADA or other antiretroviral drugs (i.e., several reverse transcriptase, protease and entry inhibitors), alone and in combination. After 4 days, IC50 was determined for the various drugs in replicate assays. Analysis of combined effects was performed using the median effect principle (CalcuSyn; Biosoft).', 'The entry inhibitor CADA exerted a potent and consistent anti-HIV-1 activity against a wide range of R5, R5/X4 and X4 primary isolates in PBMC. From the two-drug studies, combination indices showed synergy between CADA and reverse transcriptase inhibitors (zidovudine, stavudine, lamivudine, zalcitabine, didanosine, abacavir, tenofovir, nevirapine, delavirdine and efavirenz), and protease inhibitors (lopinavir, saquinavir, indinavir, nelfinavir, amprenavir and ritonavir). In addition, the combination of CADA with the gp41 fusion inhibitor T-20 (enfuvirtide), the CXCR4 antagonist AMD3100 and the gp120-specific interacting plant lectins from Galanthus nivalis (GNA) and Hippeastrum hybrid (HHA) also resulted in a synergistic inhibition.
Answer: Compounds that can specifically downmodulate the CD4 receptor in PBMC have broad-spectrum anti-HIV activity against primary isolates and act synergistically when used in conjunction with currently available antiretroviral drugs. They deserve further study as potential candidate anti-HIV drugs.
[EX A]:
Is cADA , a novel CD4-targeted HIV inhibitor , synergistic with various anti-HIV drugs in vitro?