Endothelium-dependent vasodilation in response to Pseudomonas aeruginosa lipopolysaccharide: an in vitro study on canine arteries

Early systemic arterial hypotension is a common clinical feature of Pseudomonas septicemia. To determine if Pseudomonas aeruginosa endotoxin induces the release of endothelium-derived nitric oxide (EDNO), an endogenous nitrovasodilator, segments of canine femoral, renal, hepatic, superior mesenteric, and left circumflex coronary arteries were suspended in organ chambers (physiological salt solution, 95% O2/5% CO2, pH 7.4, 37 degrees C) to measure isometric force. In arterial segments contracted with 2 microM prostaglandin F2 alpha, Pseudomonas endotoxin (lipopolysaccharide (LPS) serotype 10(Habs) from Pseudomonas aeruginosa (0.05 to 0.50 mg/ml) induced concentration-dependent relaxation of segments with endothelium (P < 0.05) but no significant change in tension of arteries without endothelium. Endothelium-dependent relaxation in response to Pseudomonas LPS occurred in the presence of 1 microM indomethacin, but could be blocked in the coronary artery with 10 microM NG-monomethyl-L-arginine (L-NMMA), a competitive inhibitor of nitric oxide synthesis from L-arginine. The inhibitory effect of L-NMMA on LPS-mediated vasorelaxation of the coronary artery could be reversed by exogenous 100 microM L-arginine but not by 100 microM D-arginine. These experiments indicate that Pseudomonas endotoxin induces synthesis of nitric oxide from L-arginine by the vascular endothelium. LPS-mediated production of EDNO by the endothelium, possibly through the action of constitutive nitric oxide synthase (NOSc), may decrease systemic vascular resistance and may be the mechanism of early hypotension characteristic of Pseudomonas septicemia.

Clinical high risk for psychosis in bipolar disorder: Clinical features, cognition and functioning

Bipolar disorder (BD) is a heterogeneous disease in terms of clinical course, neurocognitive and social-cognitive features, and functioning. Given the overlap between BD and schizophrenia, psychosis high-risk criteria that persist during euthymia may define a subgroup that differs in clinical features and functioning. In this study, we defined a subgroup of BD as ' Bipolar Disorder with Clinical High-Risk for Psychosis (BD-CHR-P)'. Our main aim was to investigate the differences in neurocognition, social cognition, psychosocial functioning, thought disorder, and clinical features in this subgroup and compare them with the BD group without this syndrome. 77 participants are included in this study. According to the Structured Interview for Prodromal Syndromes (SIPS), 25 participants were included in the BD-CHR-P group. Clinical features, cognition, functionality, thought disorder, apathy, impulsivity, and schizotypy were compared between the groups. Individuals with BD-CHR-P showed a higher rate of psychotic features in their manic episodes, and they displayed more Schneiderian symptoms in psychotic manic episodes (p = 0.049). BD-CHR-P group displayed worse functioning (F = 14.153, p < 0.001). The scores of anticipatory anhedonia (F = 5.27, p = 0.024) and positive formal thought disorder were higher in BD-CHR-P (F = 4.486, p = 0.037). In self-report evaluations impulsivity, self-report apathy, and schizotypy scores in the BD-CHR-P group were significantly higher than the BD-nonCHR-P group (F = 5.305, p = 0.024, F = 5.487, p = 0.022, F = 22.759, p < 0.001, respectively). The BD-CHR-P group exhibited poorer functioning. Further studies are needed to elucidate the mechanisms underlying the between-group differences. Moreover, cross-sectional characteristics of the BD-CHR-P group may help identify a subgroup that will develop psychotic disorders in the future.

One-hour exposure to University of Wisconsin solution does not impair endothelium-dependent relaxation or damage vascular smooth muscle of epicardial coronary arteries

To determine whether University of Wisconsin solution impairs production of endothelium-derived relaxing factor or damages vascular smooth muscle function of epicardial coronary arteries, isolated segments of canine left circumflex coronary artery were exposed to either cold (7 degrees C) or normothermic (37 degrees C) University of Wisconsin solution or to cold (30 degrees C) or normothermic (37 degrees C) physiologic salt solution in vitro for 60 minutes. After incubation with the solutions, the vascular segments were studied in vitro in organ chambers. Exposure to cold or to normothermic University of Wisconsin solution did not alter endothelium-dependent relaxation (either maximal relaxation or ED50) of the segments in response to adenosine diphosphate or acetylcholine (10(-9) to 10(-4) mol/L). Also, contraction of the segments in response to potassium ions (voltage-dependent) or prostaglandin F2 alpha (receptor-dependent) and relaxation in response to isoproterenol (cyclic AMP-mediated) or sodium nitroprusside (cyclic GMP-mediated) were unaltered after exposure to cold University of Wisconsin solution. Direct exposure to normothermic University of Wisconsin solution induced transient vasoconstriction in segments with or without endothelium. Thus University of Wisconsin solution does not irreversibly impair release of endothelium-derived relaxing factor or alter function of vascular smooth muscle in epicardial coronary arteries.

Clinical and prognostic features of patients with pandemic 2009 influenza A (H1N1) virus in the intensive care unit

OBJECTIVE

To investigate the clinical and prognostic features of patients admitted to intensive care unit (ICU) with pandemic 2009 influenza A (H1N1) virus.

METHODS

Patients admitted to the intensive care unit for severe pneumonia associated with pandemic 2009 influenza A (H1N1) virus were evaluated.

RESULTS

The study included 20 patients with the mean age of 36±13. Of the 20 subjects, 17 (85%) had underlying conditions. Of the 20 patients, 11(55%) were discharged and 9 (45%) died. Cardinal symptoms were fever, myalgia, and hemoptysis with the rates of 85 %, 75 % and 45 %, respectively. All patients had pneumonic infiltrations in their chest roentgenograms. Main laboratory findings were lymphopenia, high creatin phosphokinase (CPK) and Lactate dehydrogenase (LDH) levels. All patients had positivity on real time reverse transcription-polymerase chain reaction (RT-PCR). None of the patients had pandemic 2009 influenza A (H1N1) virus vaccination. None of them had taken oseltamivir within 48 hours. Main reasons for mortality were cardiovascular complications and ventilatory associated pneumonia due to Acynetobacter baumannii.

CONCLUSION

Early diagnosis and antiviral treatment in these cases seem to be the best approach to avoid serious illness. Special attention should be given to patients having underlying conditions such as cardiovascular and pulmonary diseases and pregnancy.