Vascular calcification: contribution of parathyroid hormone in renal failure

Hyperphosphatemia is a driving force in the pathogenesis of vascular calcification (VC) and secondary hyperparathyroidism associated with renal failure. To test for the possible contribution of parathyroid hormone (PTH) to cardiovascular calcification, we removed the parathyroid glands from rats but infused synthetic hormone at a supraphysiologic rate. All rats were pair-fed low, normal, or high phosphorus diets and subjected to a sham or 5/6 nephrectomy (remnant kidney). Control rats were given a normal diet and underwent both sham parathyroidectomy and 5/6 nephrectomy. Heart weight/body weight ratios and serum creatinine levels were higher in remnant kidney rats than in the sham-operated rats. Remnant kidney rats on the high phosphorus diet and PTH replacement developed hyperphosphatemia and hypocalcemia along with low bone trabecular volume. Remnant kidney rats on the low phosphorus diet or intact kidney rats on a normal phosphorus diet, each with hormone replacement, developed hypercalcemia. All rats on PTH replacement developed intense aortic medial calcification, and some animals presented coronary calcification. We suggest that high PTH levels induce high bone turnover and medial calcification resembling M?mckeberg's sclerosis independent of uremia. This model may be useful in defining mechanisms underlying VC.     

Writing epilepsy: a neurophysiological, neuropsychological and neuroimaging study

Writing epilepsy is a rare reflex syndrome in which seizures are triggered by writing. We describe a 33-year-old, right-handed man, with a history of juvenile absence epilepsy in remission and a family history of epilepsy, in whom myoclonic jerks precipitated exclusively by writing started at the age of 30. Intensive video/EEG monitoring during neuropsychological tests revealed, at about 1 minute after starting to write, a dystonic posture, followed by myoclonic jerks involving the right hand that shortly after became generalized. Concomitantly, the ictal EEG documented generalized hypersynchronous polyspike-wave discharges, maximal over the right parietocentral area. SPECT revealed an ictal hyperperfusion and interictal hypoperfusion over right parietofrontal regions, and fMRI showed extensive and intense left frontal, supplementary motor area activation, induced by writing. This case study provides some evidence supporting the hypothesis that the mechanism underlying writing-triggered seizures may be a generalized seizure process, with a focal cortical trigger zone, presumed to be the left frontal lobe as suggested by clinical and fMRI data. A relevant role played by the right hemisphere (right parietofrontal region) is postulated in the full-blown expression of reflex epileptogenesis, as supported by EEG and SPECT findings.     

ACCM/PALS haemodynamic support guidelines for paediatric septic shock: an outcomes comparison with and without monitoring central venous oxygen saturation

INTRODUCTION: The ACCM/PALS guidelines address early correction of paediatric septic shock using conventional measures. In the evolution of these recommendations, indirect measures of the balance between systemic oxygen delivery and demands using central venous or superior vena cava oxygen saturation (ScvO(2) > or = 70%) in a goal-directed approach have been added. However, while these additional goal-directed endpoints are based on evidence-based adult studies, the extrapolation to the paediatric patient remains unvalidated. OBJECTIVE: The purpose of this study was to compare treatment according to ACCM/PALS guidelines, performed with and without ScvO(2) goal-directed therapy, on the morbidity and mortality rate of children with severe sepsis and septic shock. DESIGN, PARTICIPANTS AND INTERVENTIONS: Children and adolescents with severe sepsis or fluid-refractory septic shock were randomly assigned to ACCM/PALS with or without ScvO(2) goal-directed resuscitation. MEASUREMENTS: Twenty-eight-day mortality was the primary endpoint. RESULTS: Of the 102 enrolled patients, 51 received ACCM/PALS with ScvO(2) goal-directed therapy and 51 received ACCM/PALS without ScvO(2) goal-directed therapy. ScvO(2) goal-directed therapy resulted in less mortality (28-day mortality 11.8% vs. 39.2%, p=0.002), and fewer new organ dysfunctions (p=0.03). ScvO(2) goal-directed therapy resulted in more crystalloid (28 (20-40) vs. 5 (0-20 ml/kg, p<0.0001), blood transfusion (45.1% vs. 15.7%, p=0.002) and inotropic (29.4% vs. 7.8%, p=0.01) support in the first 6 h. CONCLUSIONS: This study supports the current ACCM/PALS guidelines. Goal-directed therapy using the endpoint of a ScvO(2)> or =70% has a significant and additive impact on the outcome of children and adolescents with septic shock.     

Diphenyl diselenide exerts anxiolytic-like effect in Wistar rats: putative roles of GABAA and 5HT receptors

Diphenyl diselenide [(PhSe)2] is an organoselenium compound which presents pharmacological antioxidant, anti-inflammatory, antinociceptive and antidepressant properties. The present study was designed to investigate the anxiolytic effect of (PhSe)2 in rats, employing the elevated plus maze task. The involvement of 5HT and GABA receptors in the anxiolytic-like effect was also evaluated. (PhSe)2 (5, 25 and 50 micromol/kg, i.p.) did not affect locomotor activity as evaluated in the open open-field test, and learning and memory when assessed in the inhibitory foot-shock avoidance task. However, (PhSe)2 at the 50 micromol/kg dose produced signs of an anxiolytic action, namely a decreased number of fecal boli in the open-field arena and an increased time spent in as well as an increased number of entries to the open arms of the elevated plus maze test. To evaluate the role of GABA and 5HT receptors in the anxiolytic-like effect of (PhSe)2, a selective GABAA receptor antagonist bicuculline, (0.75 mg/kg, i.p.), a non-selective 5HT2A/2C receptor antagonist, ritanserin (2 mg/kg, i.p.), a selective 5HT2A receptor antagonist, ketanserin (1 mg/kg, i.p.), and a selective 5HT1A receptor antagonist, WAY100635 (0.1 mg/kg, i.p.) were used. All the antagonists used were able to abolish the anxiolytic effect of (PhSe)2 suggesting that GABAA and 5HT receptors may play a role in the pharmacological property of this selenocompound in the central nervous system.