Young red blood cells; observations about the cytometric and morphologic alterations in the beginning of their life

Summary A recently described separation technique consisting of a combination of counterflow centrifugation and subsequent density (Percoll) scparation was tested for its ability to enrich red cell populations with young cells in comparison to either separation technique alone. The relative age of every fraction was determined by HbAlc measurements, resulting in the lowest HbAlc for the combination method. Conventional reticulocyte counting and floweytometric counting with thiazole orange indicated that in the youngest fractions the combination method showed the highest reticulocyte counts. There was a good correlation between manual and flowcytometric counting results. Radio-iron studies showed a two-fold enrichment with young cells in the fraction with the lowest HbAIc acquired by the combination technique in comparison to the other two methods. Cytometric measurements showed that the fractions with the lowest HbAlc were the ones with the highest MCV and MCH and the lowest MCHC. Besides loss of their RNA-material, young cells already seem to loose water and haemoglobin like older cells, resulting in a decrease of MCV and MCH and in increase in MCHC. It is concluded that combining counterflow centrifugation with subsequent density fractionation results in superior enrichment with young cells in comparison to the results of each method alone.     

Effect of angiotensin-ll blockade on systemic and hepatic haemodynamics and on the renin-angiotensin-aldosterone system in cirrhosis with ascites

We have studied the effect of angiotensin-II blockade with saralasin on the cardiovascular and hepatic hemodynamics and on the renin-angiotensin-aldosterone system in fourteen patients with cirrhosis and ascites. Control measurements showed that most of the patients had a low mean arterial pressure, high plasma volume, normal or high cardiac index, low peripheral resistance and high plasma renin activity and aldosterone concentration. The wedged hepatic venous pressure was increased in each patient and the estimated hepatic blood flow was normal in most of them. Overall, saralasin induced a significant reduction of the mean arterial pressure, cardiac index and peripheral resistance. The decrease of the peripheral resistance was greater than that of the cardiac index. Six of the patients developed a marked reduction of the mean arterial pressure with low doses of saralasin (1--2.5 microgram/kg/min), and they had significantly higher plasma renin activity and lower mean arterial pressure than the remaining eight patients who showed a slight or no hypotensive response in spite of infusing saralasin up to a dose of 10 micrograms/kg/min. Overall, the decrease of the mean arterial pressure correlated directly with the baseline values of plasma renin activity. Angiotensin-II blockade induced a significant reduction of the wedged hepatic venous pressure. The hepatic blood flow did not show any significant change. The decrease of the wedged hepatic venous pressure was directly related to the reduction of the mean arterial pressure and also to the control plasma renin activity. Our study indicates that in most patients with cirrhosis, ascites and high plasma renin activity, arterial pressure is maintained by the effect of endogenous angiotensin II on the peripheral vasculature, and we suggest that a pre-existing arterial hypotension secondary to an arteriolar vasodilatation is the cause of renin release in these patients. Our results also show that angiotensin-II blockade is accompanied by a reduction of the post-sinusoidal hepatic vascular resistance.     

Diagnosis and treatment of erectile dysfunction in retrospect

Background We sought to establish relationships between current sexual functioning, the findings of initial psychophysiological screening (PPS) and the treatment undergone in patients with erectile dysfunction (ED).
Methods A follow-up study (1–4 years later; mean time period 1.9) was carried out among 406 patients with ED, of which a representative sample of 237 responded. An extensive questionnaire was used including items dealing with the original medical examination, including PPS, treatment, subjective experience of the treatment and psychosexual functioning over the 3 months prior to the questionnaire study. Questionnaire data were linked with originally collected PPS data, including the sexual-history data.
Results Present sexual satisfaction was positively correlated with original numbers of spontaneous daytime and morning/night erections, but was not correlated with the degree of genital and sexual arousal elicited by visual sexual stimulation (VSS). Treatment results were not satisfactory in 55% of patients. Autoinjection therapy (AIT) and psychotherapy yielded higher satisfaction scores than other treatments. In general men < 40 years appeared to be more sexually active and satisfied, and to experience fewer sexual problems than the older patients.
Conclusions The occurrence of spontaneous daytime erections and morning/night erections, obtained by history taking, indicates a psychogenic cause of the ED, and has clear predictive significance for later sexual functioning. While a positive outcome of PPS suffices to make the diagnosis of non-organic ED, it does not, contrary to what we had expected, predict later sexual functioning.     

The influence of extracellular Ca2+ on the time course of isovolumetric pressure development in the guinea-pig urinary bladder

Isovolumetric contractions were induced electrically in five guinea-pig bladders in a 1.8 mm Ca²⁺ buffer solution at two different volumes. The rate of pressure development was studied by analysis of phase-plots, which are plots of the rate of change of intravesical pressure as a function of pressure. At relatively large volumes the rate of pressure development showed a biphasic nature, suggesting that two different processes were involved in different phases of contraction. Extracellular Ca²⁺ was manipulated to identify these processes. Removal of extracellular Ca²⁺ led to an 85% reduction of the maximum isovolumetric pressure in subsequent stimulations, but pressure developed faster. The biphasic nature of pressure development at large volumes tended to disappear. It was concluded that at large bladder volumes pressure development in this type of smooth muscle is determined by the release of intracellularly stored Ca²⁺ in the early phase of contraction. In the final phase the rate of pressure development is limited by the extracellular Ca²⁺ influx. At small bladder volumes the Ca²⁺ influx takes place at a higher rate, so that the contribution of intracellular Ca²⁺ release to pressure development could not be identified at these volumes.