The effect of lysosome permeability changes on DNA synthesis and mitosis of cells growing in vitro

Summary Cultures of sheep embryonic cells, when actively growing, were incubated with quinacrine (a lysosome tagg) at concentrations of 10^–7, 10^–6, 10^–5 g/ml of culture medium, for 24 hours. The mean number of mitosis and 24 hour thymidine labelled cells are an exponential function of the initial dye concentration on the culture medium. The variation of S compartment (on one hour pulse autoradiographs) suggests two different transit times of cell population at 10^–6 and 10^–7 g/ml. The distribution obtained by plotting the percentages of cells with acid phosphatase against mitotic index points to an inverse correlation between these two parameters. Multinucleation in cells obtained from 10^–5 g/ml preparations was six times more frequent as compared to the controls. In such preparations 3.2% of the cells showed nucleus-cytoplasmatic bridging with no thymidine label. The intravital stained bodies (the lysosomes) contain acid phosphatase, a PAS positive substance, ribonucleoprotein and a blue fluorescent material resisting nuclease digestion.

---

Zusammenfassung Wachsende Kulturen von Embryonalzellen des Schafes wurden mit Quinacrin, einem die Lysosomen markierenden Farbstoff, in verschiedener Konzentration (10^–5, 10^–6 und 10^–7 g/ml des Kulturmediums) für 24 Std. inkubiert. Die durchschnittliche Zahl der Mitosen und der 24stündlich mit Thymidin markierten Zellen entsprechen einer Exponentialfunktion der anfänglichen Farbstoffkonzentration im Kulturmedium. Die Variationen der S-Phase (gemessen an autoradiographischen Impulsen in einer Stunde) legt das Vorhandensein zweier verschiedener Zeiten für Zellpopulationen bei 10^–6 und 10^–7 g/ml nahe. Der Vergleich des Prozentsatzes der Zellen mit sauerer Phosphatase mit dem Mitoseindex spricht für ein gegensätzliches Verhalten beider Parameter. Vielkernigkeit war bei den Zellen von den 10^–5 g/ml-Präparaten sechsmal häufiger als in den Kontrollen. In den Präparaten zeigten 3,2% der Zellen Kern-Cytoplasma-Brücken ohne Thymidinmarkierung. Die intravital gefärbten Lysosomen enthielten sauere Phosphatase, eine PAS-positive Substanz, Ribonucleoprotein und einen blau fluorescierenden Stoff, der resistent war gegen Nucleaseverdauung.

     

Heart rate variability,exercise capacity and levels of daily physical activity in children and adolescents with mild-to-moderate cystic fibrosis

Background:Autonomic nervous system balance is altered in cystic fibrosis (CF), although its influence on physical fitness has been poorly explored.Objective:This study aimed to evaluate the association of heart rate variability (HRV) with exercise capacity and levels of daily physical activity in children and adolescents with mild-to-moderate CF.Methods:A cross-sectional study including individuals with CF aged 6–18 years, not under CFTR modulator therapy, was performed. Sociodemographic (age, sex) and clinical information (airway colonization, pancreatic insufficiency, and genotyping) were collected. In addition, exercise capacity (modified shuttle test — MST), lung function (spirometry), body composition (bioimpedance), levels of daily physical activity (5-day accelerometer), and HRV (both at rest and during the MST) were evaluated.Results:30 individuals (20 females) aged 11.2±3.7 years, mean FEV162.8±27.6%, were included. A sympathovagal balance (LF/HF) increase (p<0.001) during the MST was shown, indicating a predominance of sympathetic modulation. The standard deviation of all RR intervals (SDNN) and the high frequency (HF) index during exercise correlated significantly with FEV₁ (r=0.45, p=0.01 and r=0.46, p=0.01; respectively). MST distance also correlated positively and significantly with SDNN (r=0.43, p=0.01), square root of the mean of the sums of squares of frequencies between RR intervals greater than 50 ms — RMSSD (r=0.53, p<0.01), low frequency — LF (r=0.48, p<0.01), HF (r=0.64, p<0.01), dispersion of points perpendicular to the short-term identity line — SD1 (r=0.40, p=0.02) and negatively with LF/HF (r=−0.57, p<0.01). Regarding daily physical activity, SDNN at rest (r=0.37, p=0.04) and exercise (r=0.41, p=0.02) showed positive correlations with time in moderate-to-vigorous activities. When normalizing the SDNN and classifying individuals as normal or altered, those presenting altered SDNN showed poorest FEV₁ (p=0.001) and lower exercise capacity (p=0.027).Conclusion:HRV correlates with lung function, exercise capacity and levels of daily physical activity in children and adolescents with CF. The study highlights the influence of CF on autonomic function and suggests HRV measurement as an easy tool to be used in clinical settings as an alternative marker to monitor CF individuals.     

A mixture of pesticides at environmental concentrations induces oxidative stress and cholinergic effects in the neotropical fish Rhamdia quelen

The insecticides imidacloprid (IMI), a neonicotinoid, and propoxur (PRO), an N-methylcarbamate compound, are pesticides widely used throughout the world. Although they are not used together to combat pests, both are often found in freshwater near agricultural areas. Thereby, the goal of this study was to evaluate the additive effects of IMI and PRO mixtures at environmental concentrations in relation to isolated compounds on Rhamdia quelen, a neotropical fish. The fish was exposed to IMI (0.11 µg/L), PRO (0.039 µg/L), or Mix (0.11 µg/L IMI plus 0.039 µg/L PRO) during 96 h. Glutathione S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), acetylcholinesterase (AChE) activities were determined. To verify oxidative damage thiobarbituric acid reactive substances (TBARS), protein carbonyl (PC), reactive oxygen species contents (ROS), antioxidant capacity against peroxides (ACAP) were determined in gills, liver, brain and muscle. The results shows that a mixture of these pesticides at environmental concentrations inhibited acetylcholinesterase activity in the brain and induced oxidative damage in all analyzed tissues. These results reinforce the hypothesis that mixture of contaminants present in environment could induce additive or synergistic effects on fish species.

     

Necrotizing sarcoid granulomatosis in a family of patients with sarcoidosis reinforces the association between both entities

Necrotizing sarcoid granulomatosis (NSG) is a rare entity mainly characterized by a prominent granulomatous vasculitis affecting middle-aged or old individuals and with a favorable prognosis. Although many believe it is a variant of sarcoidosis, the proper classification is still a matter of debate as some of its features are found in sarcoidosis but also in Churg-Strauss syndrome, Wegener's disease and hypersensitivity pneumonitis. In this paper, we described for the first time a case of NSG in a family with several cases of sarcoidosis, reinforcing the relationship between NSG and sarcoidosis. Additional interesting findings were the young age of the patient (15 years old), the symptoms limited to the respiratory tract (uncommon when NSG affects youngsters) and the increase in serologic markers of autoimmune disease. Though complete criteria for autoimmune disease were not present, systemic lupus erythematosus and Sjogren's syndrome are possible candidates. As sarcoidosis is described to be associated with several autoimmune diseases, this finding is an additional suggestion of the relationship between both entities.