Effects of humidity and temperature on in vitro dissolution of carbamazepine tablets

The rate and extent of dissolution of various approved marketed carbamazepine (CBZ) tablets exposed to 33, 52, 75, and 97% relative humidities at both room temperature and 40 degrees C, and saturated water vapor at room temperature were compared to fresh unstressed tablets. The dissolution data indicate that exposure of CBZ tablets to high humidity and temperature can have a profound effect on tablet disintegration and dissolution. The dissolution rates of some batches of CBZ products exposed to 97% humidity at 40 degrees C or saturated water vapor at room temperature were drastically reduced in only 6-7 days.     

Exclusive approach through the pulmonary artery or r. atrium in the surgical treatment of stenoses of the r. ventricle ejection channel (author's transl)

In the light of their experience of surgical treatment of right ventricle muscular stenoses, the authors have gradually abandoned the classical approach (ventriculotomy) and now exclusively use a new one through the tricuspid and pulmonary rings. The new approach considerably reduces the number and extent of enlargement patches in the infundibulum and should result in better preservation of the right ventricular function.     

Electrochemical and NMR characterizations of mixed polymer electrolytes based on oligoether sulfate and imide salts

Polymer electrolytes based on mixtures of lithium trifluoromethylsulfonylimide, LiTFSI and lithium oligoether sulfates dissolved in poly(oxyethylene) were studied. The properties of these mixed electrolytes i.e. thermal stability, ionic conductivities, transference numbers, diffusion coefficients and electrochemical stabilities were established in a wide range of compositions. A satisfactory compromise was found between high cationic transference numbers and high conductivities, while markedly decreasing the total amount of LiTFSI used. Since lithium oligoether sulfates should be considerably less expensive than LiTFSI and easy to recycle, these mixed polymer electrolytes seem to be promising.     

The hemodynamic effects of maternal hypo- and hyperoxygenation in healthy term pregnancies

OBJECTIVE: To evaluate the hemodynamic effects of maternal hypo- and hyperoxygenation in normal term pregnancy. METHODS: Ten healthy women between 35-41 weeks' gestation were exposed to 10% oxygen in inspired air for 10 minutes and, after a 5-minute recovery period, to a stepwise increase in oxygenation with 50 and 100% oxygen for 10 minutes. Maternal ventilation, hemodynamics, and oxygenation were assessed noninvasively, and maternal and fetal vascular responses were assessed with pulsed-wave color Doppler velocimetry. Computerized cardiotocography was used for fetal heart rate (FHR) analysis. RESULTS: Substantial maternal hypoxia was achieved and accompanied by a statistically significant rise in the maternal heart rate (from 89 +/- 11 to 104 +/- 16 beats per minute) and systolic blood pressure (from 123 +/- 13 to 131 +/- 13 mmHg). Doppler measurements demonstrated a statistically significant decline in the pulsatility index (PI) of the maternal internal carotid artery (from 1.8 +/- 0.3 to 1.5 +/- 0.4) and an increase in the uterine artery PI (from 0.60 +/- 0.12 to 0.72 +/- 0.13). Baseline FHR, heart rate variability, and Doppler velocimetry in the umbilical artery and the middle cerebral artery showed no statistically significant changes. Hyperoxia did not cause changes in the maternal circulation, but the FHR decreased significantly (from 142 +/- 12 to 133 +/- 11 beats per minute). CONCLUSION: Acute short-term hypoxia modifies the maternal circulation, suggesting redistribution of maternal blood flow, but exerts no detectable effects on the healthy fetus. Maternal hyperoxygenation induces no apparent adverse effects.     

Mental status and fragile X expression in relation to FMR-1 gene mutation

The fragile X mental retardation syndrome is caused by unstable expansion of a CGG repeat in the FMR-1 gene. Clinical expression is associated with a large expansion of the CGG repeat. The mutation in the FMR-1 gene and the cytogenetic expression of the fragile site at Xq27.3 have been studied in 52 fragile X male patients. The percentage of the cytogenetic expression of the fragile site at Xq27.3 positively correlates with the mean size of the full mutation in the FMR-1 gene (p < 0.0001) irrespective of the presence of additional premutation alleles. We noted a less frequent occurrence of additional premutation alleles in adult patients compared with juveniles, suggesting a continued mitotic instability in life. Additionally, the level of mental retardation has been ascertained in 35 patients using the Stanford-Binet or Terman-Merrill test of general intelligence. The presence of a full mutation in the FMR-1 gene seemed decisive for the occurrence of mental impairment in the patient. No correlation is observed between the degree of mental retardation and the size of the full mutation. The degree of mental retardation seemed not to be influenced by the presence of premutation alleles in part of the cells in addition to a full mutation. One patient is described with the 'Prader-Willi-like' subphenotype of the fragile X syndrome, showing a deletion in the FMR-1 gene in a part of his cells in addition to a full mutation.