Extinction coefficient of thyroglobulin

The extinction coefficient at 280 nm of the solution (pH 7,2-7,4) of thyroglobulin from normal thyroid and nodular euthyroid goiter was measured with the values of 0,6-0,7 to 0,9 ml.mg-1.cm-1. The value of E1%280 as function of the iodoamino acid content depends on the morphological state of the thyroid gland. A simple method for determination of the E1%280 value by measuring of the protein absorption spectrum is proposed.     

Effect of cerebrosides on the oxidative phosphorylation and translocation of hydrogen ions in the brain and liver mitochondria of rats

Oxidative phosphorylation and translocation of hydrogen ions in the brain and liver mitochondria of albino rats were studied as affected by cerebrosides with their chronic intraperitoneal injection. Cerebrosides are shown to inhibit the rate of respiration in the brain and liver mitochondria with the presence of ADP as well as that of substrate respiration in the liver mitochondria. A decrease in the phosphorylation rate is observed in the brain and liver mitochondria. When studying kinetics of hydrogen ions translocation in the brain and liver mitochondria it was found out that fixation of hydrogen ions induced by ADP is unchanged quantitatively though the fixation time is prolonged. Release of hydrogen ions under the effect of CaCl2 decreases in the liver mitochondria.     

Noninvasive ultrasonic carotid angiography: prospective validation by contrast arteriography

A technique for the beat-by-beat measurement of stroke volume is described. Aortic blood velocity signals are obtained from a catheter-mounted electromagnetic velocity transducer and analysed by a purpose-built analog computer. The stroke volume is computed by integration of each period of systolic forward flow using the velocity signal as its sole input. Automatic compensation of flowmeter drift is incorporated and inappropriate triggering of integration by diastolic artefact is prevented by applying both amplitude and duration criteria for the recognition of systolic forward flow. Early diastolic reverse flow is excluded from integration. The cardiac output, mean aortic flow per beat, and interbeat interval are also computed from the velocity signal. With aortic pressure as an additional input signal the mean arterial pressure per beat and systemic vascular resistance can be computed. The computer outputs are calibrated by a manual method. Preliminary studies comparing values for the cardiac output measured by this system and the direct Fick technique have indicated an excellent correlation between the two methods.     

Decreasing postpartum sexual abstinence time

Postpartum sexual abstinence time can be safely shortened for most patients when episiotomy repair is done meticulously with fine PGA suture on small needles. The time preferred by patients for resumption of intercourse seems to be between the second and third postpartum week. We have seen no ill effects from this, and we feel that sexual intercourse at these early dates does not influence the healing of the episiotomy in any way.     

The molecular chaperone Hsp90 can negatively regulate the activity of a glucocorticosteroid-dependent promoter

Hsp90, a molecular chaperone required for the functioning of glucocorticosteroid receptor (GR), ensures, by direct interaction, the conformational competence of the steroid-binding pocket. In addition to having this positive function, Hsp90 maintains steroid receptors in an inactive form in the absence of hormone. However, neither the participation of Hsp90 once the pathway has been activated by the ligand nor the importance of increased Hsp90 levels in determining the amplitude of the response has ever been assessed directly. Here, by increasing the Hsp90/GR ratio in the nuclear compartment, we found an attenuation of the response to glucocorticosteroids that was not due to a nonspecific or toxic effect of the Hsp90 modified by nuclear targeting. Since this negative effect was more pronounced at high levels of hormone, when receptor and Hsp90 are maximally dissociated, the possibility of an interaction between Hsp90 and GR, already activated to a DNA-binding form, was directly investigated. Indeed GR, after in vivo activation by ligand, was still able to reassociate with Hsp90, suggesting that this interaction plays a role in vivo, possibly in receptor recycling. Moreover, the GR binding to its DNA response element was inhibited by an excess of Hsp90, pointing to a function of Hsp90 in the nuclear compartment. It is thus proposed that an increased Hsp90/GR ratio influences the responsiveness to ligand at a step that is after receptor activation. This increased ratio may be of pathophysiological relevance in the different circumstances that lead to an elevated level of nuclear Hsp90.