伴随结节性硬化的浸润性视网膜星形细胞瘤4例

众所周知，视网膜星形细胞瘤常伴有结节性硬化的表现。视网膜星形细胞瘤一般是发生在视网膜神经纤维层的无蒂轻度隆起性病变。临床上可以是单侧发生，也可以是双侧发生。可以单个病灶，也可以多个病灶。可以是透明的，也可以是不透明的。可以有钙化，也可以没有钙化。视网膜星形细胞瘤相对固定的伴有眼内结节性硬化，很少表现为浸润性增长。在很少的情况下视网膜星形细胞瘤可以表现出浸润性增长，造成局部严重并发症。     

Dextromethorphan potentiates morphine antinociception at the spinal level in rats

PURPOSE: Morphine is an effective analgesic, but adverse effects limit its clinical use in higher doses. The non-opioid antitussive, dextromethorphan (DM), can potentiate the analgesic effect of morphine and decrease the dose of morphine in acute postoperative pain, but the underlying mechanism remains unclear. We previously observed that DM increases the serum concentration of morphine in rats. Therefore, we investigated the effects of drugs administered at the spinal level to exclude possible pharmacokinetic interactions. As DM has widespread binding sites in the central nervous system [such as N-methyl-D-aspartate (NMDA) receptors, sigma receptors and alpha(3)ss(4) nicotinic receptors], we investigated whether the potentiation of morphine antinociception by DM at the spinal level is related to NMDA receptors. METHODS: We used MK-801 as a tool to block the NMDA channel first, and then studied the interaction between intrathecal (i.t.) morphine and DM. The tail-flick test was used to examine the antinociceptive effects of different combinations of morphine and other drugs in rats. RESULTS: DM (2-20 microg) or MK-801 (5-15 microg) showed no significant antinociceptive effect by themselves. The antinociceptive effect of morphine (0.5 microg, i.t.) was significantly enhanced by DM and reached the maximal potentiation (43.7%-50.4%) at doses of 2 to 10 microg. Pretreatment with MK-801 (5 or 10 microg, i.t.) significantly potentiated morphine antinociception by 49.9% or 38.7%, respectively. When rats were pretreated with MK-801, DM could not further enhance morphine antinociception (45.7% vs 50.5% and 43.3%). CONCLUSION: Our results suggest that spinal NMDA receptors play an important role in the effect of DM to potentiate morphine antinociception.     

Anterior stromal puncture for recurrent erosion: further experience and new instrumentation

Anterior stromal puncture has recently been proposed as a new treatment for recalcitrant cases of recurrent corneal erosion. Concerns about the risks of corneal perforation and scarring, as well as doubts regarding its efficacy have prevented many patients from benefiting from this procedure. We introduce a new, inexpensive, commercially available instrument designed to standardize this technique, minimize scarring, and prevent corneal perforation. In a clinical trial involving 25 consecutive patients with recurrent erosions resistant to vigorous conservative treatment, the first 11 patients underwent stromal puncture in which a straight tuberculin needle was used; the following 14 were treated with a newly designed prototype needle. All patients in this series remained free of erosions after completion of stromal puncture, except for one woman with marked diffuse anterior basement membrane dystrophy, who went on to develop spontaneous bilateral erosions. Follow-up ranged from 2 months to 30 months (mean, 13 months). There were no complications of stromal puncture, and subjective and objective evaluations revealed no significant postoperative glare. Microscopic analysis of eye bank eyes subjected to anterior stromal puncture procedures demonstrated that the new prototype needle provided shallower penetration and thus less likelihood of perforation or excessive scarring than the straight needle. Also, postoperative discomfort and scarring appeared to be significantly less in patients treated with the prototype needle.