P2X receptor stimulation amplifies complement-induced haemolysis.

Activation of the complement system evokes cell damage by insertion of membrane attack complexes, which constitute the basis of the pathogenesis of various haemolytic disorders. Recently, we found that haemolysis caused by other types of membrane pore-forming proteins such as α-haemolysin (HlyA) from Escherichia coli, α-toxin from Staphylococcus aureus and leukotoxin from Aggregatibacter actinomycetemcomitans inflict their cytotoxic effects through P2 receptor activation. Here we show that similar to haemolysis induced by HlyA, leukotoxin and α-toxin, complement-induced haemolysis is amplified through ATP release and subsequent P2 receptor activation. Similar results were found both in murine, sensitised ovine and human erythrocytes, with either human plasma or guinea pig serum as complement donors. Non-selective P2 antagonists (PPADS and suramin) concentration-dependently inhibited complement-induced haemolysis. More specific P2 receptor antagonists imply that P2X1 and P2X7 are the main receptors involved in this response. Moreover, complement activation produces a sustained increase in [Ca(2+)]i, which initially triggers significant erythrocyte shrinkage, most likely mediated by KCa3.1-dependent K(+) efflux. These results indicate that complement, similar to HlyA and α-toxin, requires purinergic signalling for full haemolysis and that activation of erythrocyte volume regulation protracts the process. This finding points to several new pathways to interfere with haemolytic diseases and implies that P2 receptor antagonists potentially can be used to prevent intravascular haemolysis.

Provider-patient communication and metabolic control.

OBJECTIVE: To determine whether nurses' and NIDDM patients' communication styles during consultations are related to subsequent metabolic control and to examine factors influencing patterns of communication in these consultations. RESEARCH DESIGN AND METHODS: A total of 47 NIDDM patients participated in the study and completed the following procedures: 1) assessment of baseline HbA1, 2) attended 3.5 days of diabetes education, 3) returned in 1 mo for a follow-up consultation with a nurse, and (4) returned in 9-12 wk for a follow-up HbA1 assessment. The communication variables coded from the consultations were the frequency with which nurses produced controlling, informative, and patient-centered utterances and the frequency with which patients sought information, engaged in decision making, and expressed negative affect. RESULTS: The results were as follows: 1) patients experienced poorer metabolic control after interacting with nurses who were more controlling and directive in their communication with patients (r = 0.39, P < 0.01); 2) the nurses' use of patient-centered responses was directly related to the degree to which patients expressed feelings (r = 0.34, P < 0.01) and exhibited decision-making behavior (r = 0.62, P < 0.01); and 3) several of the nurses' and patients' communicative behaviors were related to patient characteristics such as age, sex, education, and baseline HbA1 levels. CONCLUSIONS: The results suggest that providers' attempts to exert considerable control during consultations with NIDDM patients may be counterproductive and contribute to poorer outcomes. The findings also indicate that patient-centered behaviors (e.g., encouraging the patient's involvement, respecting the patient's opinion, and offering support) facilitate the patient's ability to be an active participant in the consultation.

[The significance of familial studies in paternity disputes]. / Význam rodinné studie v paternitních sporech.

In the majority of paternity suits no fundamental problems develop when paternity of the man is ruled out or not ruled out. The authors describe a paternity suit which lasted a total of thirteen years and only a family study confirmed practically with certainty the paternity of the accused man.

[Use of the computer for the evaluation of platelet aggregation]. / Pouzití pocítace pri hodnocení agregace desticek.

The authors describe some methods of evaluation for platelet aggregation. Because the approaches are different, frequently some results of aggregation in pathological conditions differ. The authors give an account of their method of evaluation of platelet aggregation by means of a small personal computer.

[The blood group system in paternity disputes]. / Krevní skupinové systémy ve sporech o otcovství.

The author presents a brief account of the literature on the secretory capacities of different antigenic systems on red blood cells, isoenzymes, serum proteins and the HLA system of leucocytes and provides information on his own experience when dealing with paternity suits. The certainty of elimination of men unjustly accused of paternity is high.

Efficacy of diabetes education: classroom versus individualized instruction.

A pilot study was conducted using the concerns based adoption model (CBAM) developed at the University of Texas-Austin. This model uses two diagnostic dimensions: stages of concern (SC) and levels of use (LU). Movement in these dimensions is an important determinant of self-motivated disease management. It is postulated that this self-motivation is the basis of long-term adherence to the patient's therapeutic regimen and results in the decreased use of medical services. Twenty patients who attended a series of formal diabetes education classes were compared with 20 patients who received individualized instruction. Classroom education was significantly more effective in increasing the SC about diabetes management. However, the increase in LU (technical skills) was not significantly different in either setting. At 2- to 3-month follow-up evaluation, results indicated that retention of skills and motivation are excellent and that SC and LU continued to improve. In summary, this study demonstrated that classroom education is technically equivalent, more cost-effective, and may be more conducive to learning than individualized instruction.