PubMed · 14215531
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D SNYDACKER. 1964-11-16. STRABISMUS.. https://pubmed.ncbi.nlm.nih.gov/14215531/
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The purpose of the present study was to assess the influence of autonomic blockade on shortening of effective refractory period (ERP) induced by short-term rapid atrial pacing (RAP) and its recovery process. Fifteen patients (8 men, 7 women, age 52 +/- 16 years) without structural heart disease and without a history of atrial fibrillation were included in this study. All patients underwent RAP at a cycle length of 300 ms for 5 minutes, after which the ERP was measured in all patients at 1, 3, 5, 7.5, and 10 minutes following cessation of RAP. In ten patients, these RAP and measurements of ERPs were repeated after administration of propranolol (P) and subsequent administration of atropine (P + A), respectively. In the remaining five patients atropine (A) was given first and then the administration of propranolol followed (P + A). Relative to the baseline value, the ERP immediately after RAP did not differ significantly from the Control(C), P, A, or P + A (C, 79%+/- 8%; P, 82%+/- 9%; A, 80%+/- 6%; P + A, 82%+/- 13%). However, the ERP 3 minutes after cessation of RAP was significantly (P < 0.05) longer in A (93%+/- 4%) and P + A (97%+/- 5%) than that in C (86%+/- 5%) and P (86%+/- 5%). The recovery time for ERP to return to pre-RAP value was significantly shorter during A and P + A than during either C or P (C, 536 +/- 161 s; P, 503 +/- 172 s; A, 282 +/- 111 s; P + A, 291 +/- 147 s; P < 0.05). Parasympathetic blockade may promote recovery from ERP shortening induced by short-term RAP.
The seeds of Datura metel were carried aboard a retrievable satellite and exposed to space environment. The effects of space environment (weightlessness and ionizing radiation) on the contents of atropine and scopolamine in D. metel were investigated by using an effective capillary zone electrophoresis (CZE) method, which employed 50 mmol/l phosphate buffer (pH 8) containing 10% (v/v) tetrahydrofuran as the running buffer. The results showed that the contents of atropine and scopolamine varied to some extent, and the earth-control group has the lowest content of atropine. However, the variation of atropine and scopolamine contents in three groups was not obvious based on t-test. At the same time, the optimization of the separation was discussed in detail and the two compounds were completely separated within 10 min with satisfactory repeatability and calibration linearity.
A method for the separation of atropine enantiomers, D- and L-hyoscyamine by capillary electrophoresis (CE) has been developed and validated. The advantages of the CE method compared with polarimetry include smaller amounts of analytes and a lower limit of detection of the unwanted enantiomer. Moreover, the present method enables a baseline separation of the analytes and tropic acid, one of the typical impurities of atropine. The developed enantioseparation of atropine was performed using a commercially available sulfated beta-cyclodextrin and was validated for the determination of L-hyoscyamine in atropine as well as for the enantiomeric purity of L-hyoscyamine.