Pregabalin as an analgesic option for patients undergoing thoracotomy: cost analysis of pregabalin versus epidural analgesia for post-thoracotomy pain relief.

BACKGROUND: Our previous randomized controlled trial (RCT) to evaluate the effects of pregabalin on acute post-thoracotomy pain compared with epidural analgesia showed that pregabalin is a safe and effective treatment and that it may be an alternative to epidural analgesia for acute post-thoracotomy pain. In this analysis, to additionally analyze the economic aspects of pregabalin in patients undergoing thoracotomy, we compared the medical costs between pregabalin and epidural analgesia as an analgesic technique for post-thoracotomy pain. METHODS: Costs for patients undergoing thoracotomy and receiving either pregabalin or epidural analgesia for post-thoracotomy pain relief in the previous RCT were retrospectively collected from health insurance claims data. The following five cost categories were compared between the groups: (I) surgery costs; (II) costs for surgical materials and medications; (III) costs for anesthetic management; (IV) total hospitalization costs; and (V) costs for outpatient pain-relief medications (from hospital discharge to 6 months after thoracotomy). RESULTS: We analyzed data from 90 patients (45 patients for each group). Median costs for surgical materials and medications and those for anesthetic management were significantly lower in the pregabalin group than in the epidural analgesia group [(Japanese yen) ¥69,720 vs. ¥77,180, P=0.017; ¥161,000 vs. ¥195,500, P<0.001, respectively]. However, total hospitalization costs and costs for outpatient pain-relief medications were similar between the groups. Pregabalin was prescribed to more patients in the pregabalin group than those in the epidural analgesia group as outpatient treatment (75.0% vs. 37.5%), but median prescribed doses were much smaller in the pregabalin group. CONCLUSIONS: Although the use of pregabalin did not result in lower total hospitalization costs, it may reduce fee-for-service surgery- and anesthesia-related costs. The economic benefits of pregabalin may reinforce its usefulness as an alternative to epidural analgesia, especially for patients who are unsuitable for epidural analgesia.

Differential muscle regulatory factor gene expression between larval and adult myogenesis in the frog Xenopus laevis: adult myogenic cell-specific myf5 upregulation and its relation to the notochord suppression of adult muscle differentiation.

During Xenopus laevis metamorphosis, larval-to-adult muscle conversion depends on the differential responses of adult and larval myogenic cells to thyroid hormone. Essential differences in cell growth, differentiation, and hormone-dependent life-or-death fate have been reported between cultured larval (tail) and adult (hindlimb) myogenic cells. A previous study revealed that tail notochord cells suppress terminal differentiation in adult (but not larval) myogenic cells. However, little is known about the differences in expression patterns of myogenic regulatory factors (MRF) and the satellite cell marker Pax7 between adult and larval myogenic cells. In the present study, we compared mRNA expression of these factors between the two types. At first, reverse transcription polymerase chain reaction analysis of hindlimb buds showed sequential upregulation of myf5, myogenin, myod, and mrf4 during stages 50-54, when limb buds elongate and muscles begin to form. By contrast, in the tail, there was no such increase during the same period. Secondary, these results were duplicated in vitro: adult myogenic cells upregulated myf5, myod, and pax7 in the early culture period, followed by myogenin upregulation and myotube differentiation, while larval myogenic cells did not upregulate these genes and precociously started myotube differentiation. Thirdly, myf5 upregulation and early-phase proliferation in adult myogenic cells were potently inhibited by the presence of notochord cells, suggesting that notochord cells suppress adult myogenesis through inhibiting the transition from Myf5(-) stem cells to Myf5(+) committed myoblasts. All of the data presented here suggest that myf5 upregulation can be a good criterion for the activation of adult myogenesis during X. laevis metamorphosis.

Adult-type myogenesis of the frog Xenopus laevis specifically suppressed by notochord cells but promoted by spinal cord cells in vitro.

Larval-to-adult myogenic conversion occurs in the dorsal muscle but not in the tail muscle during Xenopus laevis metamorphosis. To know the mechanism for tail-specific suppression of adult myogenesis, response character was compared between adult myogenic cells (Ad-cells) and larval tail myogenic cells (La-cells) to a Sonic hedgehog (Shh) inhibitor, notochord (Nc) cells, and spinal cord (SC) cells in vitro. Cyclopamine, an Shh inhibitor, suppressed the differentiation of cultured Ad (but not La) cells, suggesting the significance of Shh signaling in promoting adult myogenesis. To test the possibility that Shh-producing axial elements (notochord and spinal cord) regulate adult myogenesis, Ad-cells or La-cells were co-cultured with Nc or SC cells. The results showed that differentiation of Ad-cells were strongly inhibited by Nc cells but promoted by SC cells. If Ad-cells were "separately" co-cultured with Nc cells without direct cell-cell interactions, adult differentiation was not inhibited but rather promoted, suggesting that Nc cells have two roles, one is a short-range suppression and another is a long-range promotion for adult myogenesis. Immunohistochemical analysis showed both notochord and spinal cord express the N-terminal Shh fragment throughout metamorphosis. The "spinal cord-promotion" and long-range effect by Nc cells on adult myogenesis is thus involved in Shh signaling, while the signaling concerning the short-range "Nc suppression" will be determined by future studies. Interestingly, these effects, "Nc suppression" and "SC promotion" were not observed for La-cells. Situation where the spinal cord/notochord cross-sectional ratio is quite larger in tadpole trunk than in the tail seems to contribute to trunk-specific promotion and tail-specific suppression of adult myogenesis during Xenopus metamorphosis.