Normal pressure hydrocephalus and cerebral blood flow: a PET study of baseline values.

Regional cerebral blood flow (CBF) was studied with O(15)-water positron emission tomography and anatomic region-of-interest analysis on co-registered magnetic resonance in patients with idiopathic (n = 12) and secondary (n = 5) normal pressure hydrocephalus (NPH). Mean CBF was compared with values obtained from healthy volunteers (n = 12) and with clinical parameters. Mean CBF was significantly decreased in the cerebrum and cerebellum of patients with NPH. The regional analysis demonstrated that CBF was reduced in the basal ganglia and the thalamus but not in white matter regions. The results suggest that the role of the basal ganglia and thalamus in NPH may be more prominent than currently appreciated. The implications for theories regarding the pathogenesis of NPH are discussed.     

Identification and characterization of aquaporin-2 water channel mutations causing nephrogenic diabetes insipidus with partial vasopressin response

Congenital nephrogenic diabetes insipidus (NDI) is a rare disease caused most often by mutations in the vasopressin V2 receptor (AVPR2). We studied a family which included a female patient with NDI with symptoms dating from infancy. The patient responded to large doses of desmopressin (dDAVP) which decreased urine volume from 10 to 4 I/day. Neither the parents nor the three sisters were polyuric. The patient was found to be a compound heterozygote for two novel recessive point mutations in the aquaporin-2 (AQP2) gene: L22V in exon 1 and C181W in exon 3. Residue Cys181 in AQP2 is the site for inhibition of water permeation by mercurial compounds and is located near to the NPA motif conserved in all aquaporins. Osmotic water permeability (Pf) in Xenopus oocytes injected with cRNA encoding C181W-AQP2 was not increased over water control, while expression of L22V cRNA increased the Pf to approximately 60% of that for wild-type AQP2. Co-injection of the mutant cRNAs with the wild-type cRNA did not affect the function of the wild-type AQP2. Immunolocalization of AQP2-transfected CHO cells showed that the C181W mutant had an endoplasmic reticulum-like intracellular distribution, whereas L22V and wild-type AQP2 showed endosome and plasma membrane staining. Water permeability assays showed a high Pf in cells expressing wild-type and L22V AQP2. This study indicates that AQP2 mutations can confer partially responsive NDI.      

ATG16L1 and NOD2 polymorphisms enhance phagocytosis in monocytes of Crohn’s disease patients

AIM:To investigate if the presence of relevant genetic polymorphisms has effect on the effectual clearance of bacteria by monocytes and granulocytes in patients with Crohn’s disease(CD).METHODS:In this study,we assessed the differential responses in phagocytosis by measuring the phagocytic activity and the percentage of active phagocytic monocytes and granulocytes in inflammatory bowel disease patients as well as healthy controls.As both autophagy related like 1(ATG16L1)and immunityrelated guanosine triphosphatase gene are autophagy genes associated with CD and more recently nucleo-tide-binding ligomerization domain-containing protein2(NOD2)has been identified as a potent inducer of autophagy we genotyped the patients for these variants and correlated this to the phagocytic reaction.The genotyping was done with restriction fragment length polymorphisms analysis and the phagocytosis was determined with the pHrodo?Escherichia coli Bioparticles Phagocytosis kit for flowcytometry.RESULTS:In this study,we demonstrate that analysis of the monocyte and granulocyte populations of patients with CD and ulcerative colitis showed a comparable phagocytic activity(ratio of mean fluorescence intensity)between the patient groups and the healthy controls.CD patients show a significantly higher phagocytic capacity(ratio mean percentage of phagocytic cells)compared to healthy controls(51.91%±2.85%vs 37.67%±7.06%,P=0.05).The extend of disease was not of influence.However,variants of ATG16L1(WT:2.03±0.19 vs homozygoot variant:4.38±0.37,P<0.009)as well as NOD2(C-ins)(heterozygous variant:42.08±2.94 vs homozygous variant:75.58±4.34(P=0.05)are associated with the phagocytic activity in patients with CD.CONCLUSION:Monocytes of CD patients show enhanced phagocytosis associated with the presence of ATG16L1 and NOD2 variants.This could be part of the pathophysiological mechanism resulting in the disease.     

Evaluation of Efficacy of Microwave Irradiation in Disinfecting Dental Gypsum Casts: An Ex Vivo Study

The aim of this study is to assess the efficacy of microwave irradiation in disinfecting gypsum casts and also to compare its efficacy with validated method of chemical disinfection. The present study is an ex vivo study conducted on a sample of five irreversible hydrocolloid impressions in vitro and on ten patients gypsum casts in vivo following standard impression techniques to check the efficacy of microwave oven irradiation and compare its efficacy with standard chemical method of disinfection. Results were analysed using Mann–Whitney test and Wilcoxon signed rank test. Untreated gypsum casts showed cfu/ml counts with a median log value of 6, while microwave-irradiated ones had median cfu/ml counts of 0. Casts poured from chemically disinfected impressions demonstrated cfu/ml counts with a median log value of 5. Microwave irradiation was found to be effective in disinfecting gypsum casts when compared to chemical disinfectant in disinfecting dental impressions.     

Impact of duration of symptoms on CSF dynamics in idiopathic normal pressure hydrocephalus

Czosnyka Z, Owler B, Keong N, Santarius T, Baledent O, Pickard JD, Czosnyka M. Impact of duration of symptoms on CSF dynamics in idiopathic normal pressure hydrocephalus.
Acta Neurol Scand: 2011: 123: 414–418.
© 2010 John Wiley & Sons A/S. Objective – Cerebrospinal fluid (CSF) pressure–volume compensation may change over time as part of normal ageing, where the resistance to CSF outflow increases and the formation of CSF decreases with age. Is CSF compensation dependent on duration of symptoms in idiopathic normal pressure hydrocephalus (iNPH)? Methods – We investigated 92 patients presenting with iNPH. Mean age was 73 (range 47–86). There were 60 men and 32 women. They all presented with gait disturbance and ventricular dilatation. Memory deficit occurred in 72% and urinary incontinence in 52% of patients. All patients underwent computerized CSF infusion tests. Sixty‐four shunted patients were available for follow‐up, and their improvement was expressed using the NPH score. Results – Mean intracranial pressure (ICP) was 10.1 ± 5.1 mmHg, and mean resistance to CSF outflow was 17.3 ± 5.2 mmHg/(ml/min). Mean duration of symptoms was 24 ± 19 months (range from 2 weeks to 86 months). Baseline ICP, magnitude of ICP pulse waveform, brain compliance and improvement after shunting (72% of patients improved) did not exhibit any dependency on the duration of symptoms. The resistance to CSF outflow showed a strong tendency to decrease in time with the duration of symptoms beyond 2 years (R = −0.702; P < 0.005). Conclusion – This is a preliminary observation, and it suggests that for patients with duration of symptoms longer than 2–3 years, the threshold for normal resistance to CSF outflow should be duration‐adjusted.     

Idiopathic intracranial hypertension: 12 cases treated by venous sinus stenting

BACKGROUND: The high pressures documented in the intracranial venous sinuses in idiopathic intracranial hypertension (IIH) could be the result of focal stenotic lesions in the lateral sinuses obstructing cranial venous outflow. OBJECTIVE: To explore the relation between venous sinus disease and IIH. METHODS: 12 patients with refractory IIH had dilatation and stenting of the venous sinuses after venography and manometry had shown intracranial venous hypertension proximal to stenoses in the lateral sinuses. Intrasinus pressures were recorded before and after the procedure and correlated with clinical outcome. RESULTS: Intrasinus pressures were variably reduced by stenting. Five patients were rendered asymptomatic, two were improved, and five were unchanged. CONCLUSIONS: The importance of venous sinus disease in the aetiology of IIH is probably underestimated. Lateral sinus stenting shows promise as an alternative treatment to neurosurgical intervention in intractable cases.     

Extradural hematoma causing venous sinus obstruction and pseudotumor cerebri syndrome

Case report The case of a small right occipital extradural hematoma in a 10-year-old girl is presented. The patient had bifrontal occipital headache out of proportion to the size of the hematoma, as well as diplopia. MR venography revealed compression and occlusion of the dominant right transverse sinus resulting in a pseudotumor cerebri syndrome.Discussion The relationship between venous sinus obstruction and the pseudotumor syndrome is discussed. Clinicians should be aware of the possible effects of an extra-axial collection on the cerebral venous sinuses.