Salicylic-acid elicited phospholipase D responses in Capsicum chinense cell cultures.

The plant response to different stress types can occur through stimulus recognition and the subsequent signal transduction through second messengers that send information to the regulation of metabolism and the expression of defense genes. The phospholipidic signaling pathway forms part of the plant response to several phytoregulators, such as salicylic acid (SA), which has been widely used to stimulate secondary metabolite production in cell cultures. In this work, we studied the effects of SA treatment on [(32)-P]Pi phospholipid turnover and phospholipase D (PLD) activity using cultured Capsicum chinense cells. In cultured cells, the PIP2 turnover showed changes after SA treatment, while the most abundant phospholipids (PLs), such as phosphatidylcholine (PC), did not show changes during the temporal course. SA treatment significantly increased phosphatidic acid (PA) turnover over time compared to control cells. The PA accumulation in cells treated with 1-butanol showed a decrease in messengers; at the same time, there was a 1.5-fold increase in phosphatidylbutanol. These results suggest that the participation of the PLD pathway is a source of PA production, and the activation of this mechanism may be important in the cell responses to SA treatment.

Effect of different inhibitors on phospholipase C activity in Catharanthus roseus transformed roots.

We have previously reported that Catharanthus roseus transformed roots contain at least two phosphatidylinositol 4,5-bisphosphate-phospholipase C (PLC) activities, one soluble and one membrane associated. In this paper, the effect of neomycin and several divalent cations was analyzed, both in the soluble and the membrane-associated PLC activity in C. roseus transformed roots. In this system, neomycin, an aminoglycoside antibiotic, inhibited PLC in a concentration-dependent fashion. The neomycin IC50 (100 microM) was the same for the inhibition of the soluble and the membrane associated PLC activity. The effect of different divalent cations such as Ni2+, Cu2+, and Zn2+ was studied as well. In order to see the effect of these cations on PLC activity, we selected two conditions: a) in the presence of and b) in the absence of calcium. In the presence of calcium, these three divalent cations were able to inhibit PLC activity in both fractions in a concentration-dependent manner; however, the IC50s were different for the membrane and the soluble activities. For the soluble activity, the inhibition due to the three cations was very similar (IC50s between 0.2 and 0.3 mM). For the membrane associated PLC activity, Cu2+ was the most potent inhibitor (IC50 3.6 microM), then Ni2+ and then Zn2+. In the absence of calcium, higher concentrations of Cu2+ and Zn2+ demonstrated some inhibitory effect. We discuss the possible physiological role of these inhibitors on PLC activity.

[Autoimmune hemolytic anemia and posthepatitis-C liver cirrhosis]. / Anemia hemolítica autoinmune y cirrosis hepática posthepatitis C.

Here we are presenting the case of a 70-years-old woman who has hepatic cirrhosis anti-HCV and insulin-dependent diabetes mellitus, without relevant epidemiologic ascendants or previous transfusions and HBV, HIV negatives. On admission to our hospital she showed signs of autoimmune hemolytic anaemia (AHA) which was confirmed by positive direct Coombs test and an improvement in blood test after corticoid treatment. Having discarded other possible causes such as drugs infectious diseases or essential mixed cryoglobulinemia (CME), we put forward the possible association between AHA and infection by HCV, where AHA was an extrahepatic immunological manifestation of HCV. This fact has never been brought to light in previous medical literature.

[Evidence of abnormal kidney processing of uric acid in patients with insulin-dependent diabetes mellitus]. / Evidencia del manejo renal anormal de ácido úrico en pacientes diabéticos insulinodependientes.

Renal uric acid handling in 62 insulin dependent diabetic (IDD) patients of both sexes, without clinical or biochemical signs of nephropathy or hypertension was studied and compared to healthy age matched control groups. IDD adults (n = 38, age 45-64) presented uremia similar to controls (n = 9 age 45-64). Neither, the tubular charge or filtration charge (CFU) or the uric acid excretion fraction showed statistically significant differences. Young IDD (n = 24, age 13-37) presented levels uric acid than significantly (p less than 0.001) lowers to young controls (n = 10, age 13-38) and adults IDD (p less than 0.001). The CFU is lower in both, young and adult IDD when compared to young controls (p less than 0.02). Nevertheless, the CFU is higher in young IDD than in controls of the same age (p less than 0.001) or in adult IDD (p less than 0.001). In summary, we conclude the existence of an abnormal (uric acid) renal management caused by a tubular defect probably lying on the proximal tubular segment where the uric acid secretion is carried out.