instruction:
Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.
question:
Abstract: The role of the second messengers cAMP and Ca++ in the control of proopiomelanocortin (POMC) gene expression was investigated with the use of hybridization with cloned complementary DNA probes. The effects of cAMP-related drugs on POMC messenger RNA (mRNA) levels were assessed in primary cultures of intermediate (IL) and anterior rat pituitary cells maintained in serum-free medium. 8-Bromo-cAMP (1 mM), but not 8-bromo-cGMP (1 mM), induced a 2-fold increase in IL and anterior lobe cell after 2 days of treatment. A similar increase was obtained with the adenylate cyclase-activating drugs forskolin (1 microM) and cholera toxin (100 ng/ml) or the phosphodiesterase inhibitor RO 20-1724 (100 microM). At 48 h, all these treatments had increased beta-endorphin accumulation in the medium and transiently decreased the cellular beta-endorphin content in IL cells, suggesting a parallel effect of cAMP-related drugs on secretion and biosynthesis. Incubating the cells with the Ca++ channel antagonists D600 (50 microM), verapamil (50 microM), and the dihydropyridine nifedipine (0.1 microM) decreased basal POMC mRNA levels, whereas the dihydropyridine BAYK 8644 (0.1 microM), which activates the Ca++ channel, increased POMC mRNA levels after 2 days. In addition, nifedipine decreased the stimulatory effect of forskolin, whereas BAYK 8644 further stimulated the forskolin-increased POMC mRNA levels in IL cells. We conclude that both Ca++ and cAMP may regulate the gene expression of POMC.
answer:
Adenosine Cyclic Monophosphate

question:
Abstract: We have developed a variable suction system for irrigation, aspiration and vitrectomy. The system is regulated by the operator's finger-tip.
answer:
Equipment Design

question:
Abstract: In principle, azoospermia has two explanations: occlusion of the duct system and serious dysfunction of the testicular parenchyma. Some cases of duct occlusion are suitable for reconstructive surgery. The authors describe a reconstructive technique based on full mobilization of a single loop of the epididymal duct as caudally as possible with two-layer side-to-end anastomosis to the vas deferens. To ensure follow-up evaluation of each anastomosis, unilateral anastomosis was done primarily. In a few cases, cross-over anastomosis was necessary. In cases of reoperation, if possible, this was performed on the same side. When the epididymal duct system was found empty, the contralateral epididymis was explored. Patients with postoperative oligozoospermia were offered a supplementary contralateral operation. From 1980 to 1984, 41 patients underwent epididymovasostomy. At follow-up evaluation, 35 (85%) presented sperms in repeated tests. Fifteen of these patients (37%) have fathered children. Patients with postoperative normospermia and no antisperm antibodies had an excellent fertility prognosis. The single-loop dissection technique provides anatomic specificity and a high percentage of patent anastomoses and does not interfere with the possibilities of reoperation.
answer:
Adult