Pathogenesis of chronic cluster headache and bouts: role of tryptamine, arginine metabolism and α1-agonists.

The aim of this study was to explore the possible role of tryptamine in the pathogenesis of chronic cluster headache along with that of adrenaline and noradrenaline (α-agonists) together with arginine metabolism in the origin of cluster bouts. Plasma levels of tyramine, tryptamine, serotonin, 5-hydroxyindolacetic acid, noradrenalin, adrenalin and the markers of arginine metabolism such as arginine, homoarginine, citrulline, ADMA and NMMA, were measured in 23 chronic cluster headache patients (10 chronic cluster ab initio and 13 transformed from episodic cluster) and 28 control subjects. The plasma levels of tyramine, tryptamine, noradrenalin and adrenalin were found several times higher in chronic cluster headache patients compared to controls, whereas the plasma levels of arginine, homoarginine and citrulline were significantly lower. No differences were found in the plasma levels of serotonin, 5-hydroxyindolacetic, ADMA and NMMA between chronic cluster headache patients and control subjects. These results provide support for a role of tryptamine in the pathogenesis of chronic cluster headache and, in particular, in the duration of the cluster bouts. In addition, the low levels of the nitric oxide substrates together with the high levels of noradrenalin and adrenalin suggest an activation of endothelial TAAR1 receptors followed by the release of nitric oxide in the circulation that may constitute the final step of the physiopathology of cluster crisis.

Elevated plasma homocysteine in acute stroke was not associated with severity and outcome: stronger association with small artery disease.

Homocysteine increases in the acute phase of ischaemic stroke and from the acute to the convalescent phase, suggesting that hyper-homocysteinaemia may be a consequence rather than a causal factor. Therefore we measured homocysteine plasma levels in stroke patients in order to investigate possible correlations of homocysteine with stroke severity and clinical outcome. Further we looked for eventual differences in stroke subtypes. We prospectively studied plasma homocysteine levels in acute stroke patients admitted to the stroke unit of our department. Seven hundred and seventy-five ischaemic stroke patients, 39 cerebral haemorrhages and 421 healthy control subjects have been enrolled. Stroke severity and clinical outcome were measured with the Scandinavian Stroke Scale, the Rankin Scale and the Barthel Index. Stroke severity by linear stepwise regression analysis was not an independent determinant of plasma homocysteine levels. Homocysteine was not correlated with outcome measured by the Barthel Index. Mean plasma homocysteine of both ischaemic and haemorrhagic stroke was significantly higher than controls (p<0.05). Homocysteine had an adjusted odds ratios (OR) of 4.2 (95% CI 2.77-6.54) for ischaemic stroke and of 3.69 (95% CI 1.90-7.17) for haemorrhagic stroke. Compared with the lowest quartile, the upper quartile was associated with an adjusted OR of ischaemic stroke due to small artery disease of 17.4 (95% CI 6.8-44.3). Homocysteine in the acute phase of stroke was not associated with stroke severity or outcome. Elevated plasma homocysteine in the acute phase of stroke was associated with both ischaemic and haemorrhagic stroke. Higher levels are associated with higher risk of small artery disease subtype of stroke.

Caspase-3 and -8 activation and cytokine removal with a novel cellulose triacetate super-permeable membrane in an in vitro sepsis model.

Pro-apoptotic molecules are generated during sepsis which may be responsible for alteration of organ function in sepsis. Removal of systemic apoptotic activity may affect recovery from sepsis. Current high flux membranes might not be sufficiently permeable to eliminate pro-apoptotic factors. We evaluated the elimination of pro-apoptotic factors induced by LPS in human whole blood by a super-permeable cellulose triacetate membrane (SUREFLUX FH 150, Nipro, Osaka, Japan) in comparison to a standard high flux cellulose triacetate membrane (UT 700, Nipro, Osaka, Japan) and a polyethersulfone plasmafilter (Bellco, Mirandola Italy) in an in vitro blood circulation. We spiked human whole blood with lipopolysaccharide from Escherichia coli (Serotype 026-86, 10 mg/ml), incubated it for 3 hours to allow cytokine generation and recirculated it at 300 ml/min for 3 hours. The UF line was first returned to the blood module at 10 min. After this, the UF was drained from 10 to 60 min at a rate of 1000 ml/h. Zero balance was obtained by re-infusion of bicarbonate buffered hemofiltration fluid. Apoptosis was assessed on U937 monocytes (incubated with plasma or ultrafiltrate) by fluorescence microscopy dyes (Hoechst 33342, propidium iodide) and annexin V flow cytometry. Caspase-3 and Caspase-8 activity was assessed on the recirculated blood monocytes by spectrophotometric methods. IL-2, IL-10 and TNFalpha were determined by commercially available ELISAs. Sieving coefficients and clearances were determined for the different cytokines. Caspase-3 and Caspase-8 were activated by LPS and remained either stable or increased during in vitro circulation. Apoptosis activity of U937 cells, when incubated with the ultrafiltrate, increased in parallel with arterial plasma values (for Uf: UT700 = 23.1%; Sureflux FH150 = 42.5%). However, by 60 min the apoptotic activity recorded with the ultrafiltrate was reduced to the levels of arterial plasma (for Uf: UT700 = 19.8%; Sureflux FH150 = 11.2%). Sieving coefficients in the super-permeable membrane were significantly higher for all measured cytokines in comparison to the standard high flux membrane (e.g. TNFalpha 0.72 vs 0.03 p < 0.001) and close to the values observed for the plasmafiltration membrane. Nevertheless protein losses measured by albumin leakage were much lower with the Sureflux filter in comparison to the plasmafilter. In conclusion, pro-apoptotic factors can be eliminated by dialytic membranes with the removal rate maximized by using super high flux dialysers which may represent a compromise between hemofiltration and plasmafiltration membranes.

Temporal profile of serum anti-inflammatory and pro-inflammatory interleukins in acute ischemic stroke patients.

The presence of an inflammatory response in the pathophysiology of acute brain ischemia is relatively well established, but less is known about the anti-inflammatory mechanisms. The aim of the present study was to evaluate part of the immune response in acute stroke patients and to analyze a possible correlation with other hematological parameters, clinical outcome, size of infarct and subtypes of strokes. We prospectively studied 42 stroke patients, without signs of infections or inflammatory diseases, at days 0, 1, 3, 7 and 14, and 39 healthy control subjects. We measured serum levels of the anti-inflammatory cytokine interleukin-10 (IL-10) and the pro-inflammatory cytokine interleukin-6 (IL-6) by ELISA method. We observed a highly inverse correlation between these two molecules in control subjects (r=-0.78, p=0.0000001), and this correlation was lost in stroke patients. Patients had significantly lowered IL-10 serum levels soon after the acute event (p=0.00005), with a slight increase at the seventh day. On the other hand, patients had increased IL-6 serum levels compared with controls after day one until day 14 (p<0.04), with a maximum increase at day 3. Interleukin-6 correlated with clinical outcome whereas interleukin-10 did not. Low levels of interleukin-10 indicate that the antiinflammatory response is down-regulated in acute stroke patients. The pro-inflammatory response begins 24 hours after the onset of acute cerebral ischemia, as indicated by the increased serum levels of interleukin-6. The physiological balance between these two molecules is altered in acute stroke patients.

Removal of platelet-activating factor in experimental continuous arteriovenous hemofiltration.

OBJECTIVE: There is a positive correlation between the amount of ultrafiltration and the improved survival rate of patients with ischemia or sepsis-induced acute renal failure. Continuous arteriovenous hemofiltration (CAVH) removes vasoactive substances with a molecular weight of < 1000 daltons. This study evaluated the removal of platelet-activating factor, a lipid mediator of endotoxic shock, by CAVH with respect to kinetics, adsorption, and ultrafiltration. DESIGN: Prospective laboratory study. SUBJECTS: Normal human subjects. INTERVENTIONS: Radioactive [3H] or biologically active platelet-activating factor was added to whole blood or washed blood resuspended in Tris-buffered (pH 7.2) physiologic saline with 4% human serum albumin or plasma. Whole or washed blood cells or plasma were recirculated at 100 mL/min through polysulfone hemofilters for 120 mins with ultrafiltration (condition A), without ultrafiltration (condition B), or in a static condition (condition C). Concentrations of albumin, total protein, and radioactive or biologically active platelet-activating factor in samples obtained from the blood and ultrafiltrate compartment were determined. MEASUREMENTS: Biologically active platelet-activating factor was quantified on washed rabbit platelets and results were expressed in ng/mL over a calibration curve obtained with synthetic platelet-activating factor. MAIN RESULTS: [3H]-platelet-activating factor added to recirculated whole blood was ultrafiltered (percent of ultrafiltered platelet-activating factor/min: 0.48 +/- 0.02 [SD]; total platelet-activating factor removed in 120 mins: 15.52%; condition A) at significantly (p < .001) higher amounts than when added to washed blood cells (percent of ultrafiltered platelet-activating factor removed/min: 0.195 +/- 0.06; total platelet-activating factor removed in 120 mins: 7.46%). The highest amounts of [3H]-platelet-activating factor were bound to polysulfone membranes after recirculation with whole blood (44.5 +/- 12.2%) than with washed blood (1.1 +/- 0.3%) or plasma (11.9 +/- 0.7%). Biologically active platelet-activating factor concentrations significantly decreased in both conditions A and B (maximal decrease at 120 mins: 63% and 59%, respectively). No significant reduction could be observed in condition C. CONCLUSIONS: These studies provide experimental evidence for the prompt, efficient removal of platelet-activating factor in CAVH and provide a possible rationale for the beneficial effect of this therapy in the development of multiple organ failure in sepsis.

Fibrinogen survival and fibrinopeptide A in acute leukemia.

BACKGROUND. Hypofibrinogenemia and increased fibrin(ogen) degradation products in acute leukemia have been attributed to intravascular thrombin generation triggered by leukemic cells. However, the strict relationship between fibrinogen catabolism and turnover of fibrinopeptide A (FPA), which is a sensitive and specific marker of thrombin activity, has not been evaluated in acute leukemia (AL) with or without disseminated intravascular coagulation (DIC) to see whether mechanisms other than thrombin activity could be responsible for fibrinogen consumption. We report here the 125I-fibrinogen kinetics and FPA measurements in 19 patients with AL, 6 of them with DIC. METHODS AND RESULTS. Radiolabelled fibrinogen kinetics were studied in all the patients concomitantly with the start of chemotherapy. Fibrinopeptide A was measured by a radioimmunoassay at time of diagnosis and during chemotherapy. The kinetics of disappearance of radiolabelled fibrinogen where biphasic, with a rapid phase in the first 1-3 days of chemotherapy and a subsequent slow phase associated with the reduction or disappearance of blast cells. Patients with DIC had a significantly shorter half-life and turnover than patients without DIC. The latter group had significant shortening of these parameters in comparison to normal subjects. The thrombin-dependent catabolic rate of fibrinogen, calculated from the mean level of FPA during the first phase of disappearance curve and by assuming 2 moles of FPA generated per mole of fibrinogen, was similar in patients without DIC and in normal subjects, whereas patients with DIC had a significantly higher catabolic rate, even though the increase was not sufficient to account for all the turnover of fibrinogen. No relationship was observed between fibrinogen turnover and FPA turnover.

[Primary intestinal lymphangiectasis. A case treated surgically]. / Linfangectasia intestinale primitiva (L.I.P.). Un caso di trattamento chirurgico.

The authors describe a rare case of primary intestinal lymphangiectasis resolved with surgical treatment. Usually the natural course of the disease is relatively mild and medical nutritional treatment can be sufficient. In this case the lymphatic intestinal anomaly was generalized to the entire small intestine but a distal ileal segment was particularly involved. The surgical resection of this intestinal tract resolved the symptomatology.