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Polyhydroxyethylmethacrylate polymers (poly-HEMA) form hydrogels that provide an excellent alternative to agar in the production of salt bridges for use in bioelectrochemical experiments. A method for the simple production of poly-HEMA salt bridges is described. The poly-HEMA bridges were compared with agar bridges of similar geometry. Whereas poly-HEMA salt bridges have a conductivity that is 20 times lower than that of agar bridges of a similar geometry, poly-HEMA bridges are capable of dissipating twice the power compared with agar bridges. The mechanical properties of the poly-HEMA bridges make them easy to manufacture, store, and sterilize. When agar bridges were compared with poly-HEMA bridges in long-term cell culture experiments, the failure rate of the agar bridges was found to be approximately 10% per week vs. a virtually nonexistent failure rate for the poly-HEMA bridges. Because poly-HEMA salt bridges are reliable, durable, and nontoxic to cells, they are a practical alternative to agar salt bridges in certain experimental designs.

Plasma cAMP was determined using the method of Toveyetal. in normal pregnant women with a mean concentration of 18.9 ± 0.8 pmol/ml (x ± SEM). Between weeks 9–12 and 33–36 of gestation, there were two peaks, with a mean cAMP of 22.5 ± 2.4, which were significantly increased in comparison to the other weeks of pregnancy. Significantly decreased values were found in patients with threatened abortion (weeks 12–28) which terminated in abortion (11.6 ± 2.4; p < 0.01). In premature labor no differences were found. During therapy with fenoterol there were highly significantly increased plasma cAMP levels (48.2 ± 2.8; p < 0.0005). During thyroid hormone therapy in euthyroid goiter, cAMP was significantly decreased (14.0 ± 1.4; p < 0.05). 1 week after cessation of therapy a highly significant increase of cAMP was observed (38.2 ± 6.9; p < 0.0005). There was a negative linear regression between T₃ and cAMP ( 2p < 0.01). In pregnancy with hypertension cAMP was significantly elevated (30.5 ± 3.8; p < 0.0005), but nearly normal under antihypertensive therapy. In pregnancy with edema only, no difference was found. Induction of labor with PGE_2Α was followed by a decrease of plasma cAMP.

Acute ischemic stroke is now considered a neurological emergency for which there are new therapies. Neurosurgeons and neurologists need to remain apprised of advances in this field. The authors discuss approved and emerging therapies for patients suffering from acute ischemic stroke, based on a review of recent publications. Currently, intravenous tissue-type plasminogen activator is the only Food and Drug Administration–approved therapy for acute ischemic stroke. Intraarterial delivery of thrombolytics is a promising treatment and may be effective in selected patients. Other therapies for acute cerebral ischemia are intriguing but still in the investigational stages.

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