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.     

Chronic zinc deficiency induces an antioxidant adaptive response in rat lung

Few studies are available about the role of dietary zinc (Zn) in respiratory diseases. Adult male rats were divided into 2 groups and fed respectively a moderate Zn-deficient diet and a Zn-adequate control diet. In lung tissue at 2 months, thiobarbituric acid-reactive species (TBARS), total glutathione, glutathione disulfide, protein carbonyls, metallothionein, and the activities of glutathione peroxidase (GPx), catalase, CuZn-superoxide dismutase (CuZnSOD) and glucose-6-phosphate dehydrogenase (G-6-PDH) were increased, but protein thiols decreased. In lung tissue at 4 months, TBARS, metallothionein, and the activities of CuZnSOD, Mn-superoxide dismutase (MnSOD) increased. The activities GPx, catalase, G-6-PDH were lower than control group. The changes were accompanied by histological alterations in Zn-deficient lung. The results provide evidence of the pro-oxidative effects of Zn-deficiency in lung, and suggest that the time of treatment play a key role in determining lung susceptibility to oxidative stress.     

Intravenous streptokinase in acute myocardial infarction. A Mexican multicentric study

To evaluate the benefits of intravenous streptokinase (SQIV) in acute myocardial infarction (AMI), we joined a group of ten Mexican university hospitals, that were coordinated by the National Institute of Cardiology of Mexico. We included patients less than 70 years of age admitted to the hospital with less than 6 hours from the onset of chest pain during their first myocardial infarction. All patients had ST segment elevation of 1.5 mm or more, and none had contraindication for SQIV. They received 1.5 millions of SQIV in one hour. Reperfusion criteria included absence of pain, ST segment reduction and a rapid rise and fall of enzyme levels. Angiographic criterion for reperfusion was the permeability of the affected coronary vessel. Of 66 patients studied, 57 (86%) had clinical reperfusion; of the 24 available angiographic studies, 92% demonstrated reperfusion. Eight (12%) of the patients had minor complications and 7 (10%) had serious complications. There were 0 deaths. We concluded that SQIV is a useful therapeutic procedure, easy to perform in general hospitals.     

Changes in ovarian LHRH receptor content during the onset of puberty in the female rat

LHRH and some of its analogs have been reported to exert inhibitory effects on ovarian function, seemingly following interaction of the neurohormone with specific, high affinity binding sites. The present experiments were undertaken to determine whether LHRH binding sites in the ovary undergo quantitative changes during the onset of puberty in the rat. Changes in LHRH receptor content were assessed by the binding of the stable LHRH analog, [D-Ala6, Pro9]-LHRH to ovarian membrane preparations. LHRH binding in prepubertal rats (anestrus, A) was 166 +/- 11 fmol/mg protein, declined gradually (to 127 +/- 14 fmol/mg protein) during the early proestrous (EP) phase of puberty--a time at which intrauterine fluid begins to accumulate and uterine weight increases more rapidly--and became even lower (75 +/- 4 fmol/mg protein) by 1300 h of the day of first proestrus (LP), prior to the initiation of the first gonadotropin surge. At the time of the surge (1600 h) binding was 70 +/- 3 fmol/mg protein. LHRH binding was minimal on the day of the first estrus (E) and increased slightly on diestrus (D). The results indicate that the ovarian steroidogenic activation that precedes the first surge of gonadotrophins in the rat is associated with a marked loss in ovarian LHRH receptor content and suggest that a reduction in LHRH inhibitory function within the ovary may be a contributing factor to the pubertal enhancement in ovarian secretory activity.