Efficacy and safety of shunt surgery in patients with idiopathic normal-pressure hydrocephalus: can we predict shunt response by preoperative magnetic resonance imaging (MRI)?

AIM: The aim of this study was to identify preoperative magnetic resonance imaging (MRI) findings that can predict the shunt responsiveness in idiopathic normal-pressure hydrocephalus (iNPH) patients and to investigate postoperative outcome and complications. MATERIALS AND METHODS: A total of 192 patients with iNPH who underwent shunt at our hospital between 2000 and 2021 were included to investigate complications. Of these, after exclusion, 127 (1-month postoperative follow-up) and 77 (1-year postoperative follow-up) patients were evaluated. The preoperative MRI features (the presence of tightness of the high-convexity subarachnoid space, Sylvian fissure enlargement, Evans' index, and callosal angle) of the shunt-response and nonresponse groups were compared, and a systematic review was conducted to evaluate whether preoperative MRI findings could predict shunt response. RESULTS: Postoperative complications within one month after surgery were observed in 6.8% (13/192), and the most common complication was hemorrhage. Changes in corpus callosum were observed in 4.2% (8/192). The shunt-response rates were 83.5% (106/127) in the 1-month follow-up group and 70.1% (54/77) in 1-year follow-up group. In the logistic regression analysis, only Evans' index measuring >0.4 had a significant negative relationship with shunt response at 1-month follow-up; however, no significant relationship was observed at 1-year follow-up. According to our systematic review, it is still controversial whether preoperative MRI findings could predict shunt response. CONCLUSION: Evans' index measure of >0.4 had a significant relationship with the shunt response in the 1-month follow-up group. In systematic reviews, there is ongoing debate about whether preoperative MRI findings can accurately predict responses to shunt surgery. Postoperative corpus callosal change was observed in 4.2% of iNPH patients.

Image findings of anti-neutrophil cytoplasmic antibody-associated vasculitis involving the skull base.

AIM: To investigate computed tomography (CT) and magnetic resonance imaging (MRI) features of skull bases involving anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV). MATERIALS AND METHODS: A retrospective review was undertaken to identify an institutional historical cohort of 17 patients with confirmed AAV who underwent CT or MRI and had skull base involvement between 2002 and 2021. Two radiologists reviewed the extent and features of the lesions, bone changes, and other MRI findings. RESULTS: A total of 17 patients (12 men; mean age ± standard deviation, 46.5 ± 17.1 years) were selected. AAV presented as infiltrative lesions with involvement at various sites. Most cases involved the paranasal sinuses (PNS; 88%, 15/17), nasopharynx (88%, 15/17), pterygopalatine fossa (82%, 14/17), and parapharyngeal space (82%, 14/17), frequently accompanied by mucosal irregularity of the PNS and nasopharynx (71%, 12/17). Central skull base and temporal bone involvement were seen in 53% (9/17) and 38% (6/16) of cases, respectively. On T1-weighted imaging (WI) and T2WI MRI, all lesions (15/15) showed predominant signal iso-intensity to grey matter. CONCLUSIONS: Although radiological findings of AAV are non-specific and skull base involvement is less common, AAV may be considered if infiltrative lesions predominantly involving the PNS, nasopharynx, pterygopalatine fossa, and parapharyngeal space with combined bone changes of skull base are seen.

Accelerated Nonenhanced 3D T1-MPRAGE Using Wave-Controlled Aliasing in Parallel Imaging for Infant Brain Imaging.

BACKGROUND AND PURPOSE: MPRAGE is the most commonly used sequence for high-resolution 3D T1-weighted imaging in pediatric patients. However, its longer scan time is a major drawback because pediatric patients are prone to motion and frequently require sedation. This study compared nonenhanced accelerated MPRAGE using wave-controlled aliasing in parallel imaging (wave-T1-MPRAGE) with standard MPRAGE in infants. MATERIALS AND METHODS: We retrospectively evaluated 68 infants (mean age, 1.78 [SD. 1.70] months) who underwent nonenhanced standard and wave-T1-MPRAGE. Two neuroradiologists independently assessed each image for image quality, artifacts, myelination degree, and anatomic delineation using the 4-point Likert scale. For diagnostic performance, both observers determined whether nonenhancing lesions were present in the brain parenchyma in 2 types of nonenhanced MPRAGE sequences. RESULTS: Wave-T1-MPRAGE showed a significantly lower mean score and lower interobserver agreement for overall image quality and anatomic delineation than standard MPRAGE (P< .001 for each). However, there were no significant differences between the 2 types of MPRAGE sequences for motion artifacts (P = .90 for observer 1, P = .14 for observer 2) and degree of myelination (P = .16 for observer 1, P = .32 for observer 2). Among the nonenhancing pathologic lesions observed on standard MPRAGE by both observers, only 2 were missed on wave-T1-MPRAGE, and they were very tiny, faint, nonhemorrhagic WM injuries. CONCLUSIONS: Although wave-T1-MPRAGE showed lower overall image quality than standard MPRAGE, the diagnostic performance for nonenhancing parenchymal lesions was comparable. Wave-T1-MPRAGE could be an alternative for diagnosing intracranial lesions in infants, with marked scan time reduction.

Usefulness of Wave-CAIPI for Postcontrast 3D T1-SPACE in the Evaluation of Brain Metastases.

BACKGROUND AND PURPOSE: High-resolution postcontrast 3D T1WI is a widely used sequence for evaluating brain metastasis, despite the long scan time. This study aimed to compare highly accelerated postcontrast 3D T1-weighted sampling perfection with application-optimized contrasts by using different flip angle evolution by using wave-controlled aliasing in parallel imaging (wave-T1-SPACE) with the commonly used standard high-resolution postcontrast 3D T1-SPACE for the evaluation of brain metastases. MATERIALS AND METHODS: Among the 387 patients who underwent postcontrast wave-T1-SPACE and standard SPACE, 56 patients with suspected brain metastases were retrospectively included. Two neuroradiologists assessed the number of enhancing lesions according to lesion size, contrast-to-noise ratiolesion/parenchyma, contrast-to-noise ratiowhite matter/gray matter, contrast ratiolesion/parenchyma, and overall image quality for the 2 different sequences. RESULTS: Although there was no significant difference in the evaluation of larger enhancing lesions (>5 mm) between the 2 different sequences (P = .66 for observer 1, P = .26 for observer 2), wave-T1-SPACE showed a significantly lower number of smaller enhancing lesions (<5 mm) than standard SPACE (1.61 [SD, 0.29] versus 2.84 [SD, 0.47] for observer 1; 1.41 [SD, 0.19] versus 2.68 [SD, 0.43] for observer 2). Furthermore, mean contrast-to-noise ratiolesion/parenchyma and overall image quality of wave-T1-SPACE were significantly lower than those in standard SPACE. CONCLUSIONS: Postcontrast wave-T1-SPACE showed comparable diagnostic performance for larger enhancing lesions (>5 mm) and marked scan time reduction compared with standard SPACE. However, postcontrast wave-T1-SPACE showed underestimation of smaller enhancing lesions (<5 mm) and lower image quality than standard SPACE. Therefore, postcontrast wave-T1-SPACE should be interpreted carefully in the evaluation of brain metastasis.

alpha-MSH decreases apoptosis in ischaemic acute renal failure in rats: possible mechanism of this beneficial effect.

BACKGROUND: Apoptosis frequently occurs in acute renal injury but the molecular mechanisms responsible for this distinct form of cell death are largely unknown. Fas belongs to the tumour necrosis factor (TNF)/nerve growth factor superfamily and engagement by Fas ligand induces apoptosis in various epithelial cells. To investigate the role of apoptosis and associated mechanisms, we examined the occurrence of apoptosis and Fas and Fas ligand expression, and the therapeutic effect of alpha-melanocyte-stimulating hormone (alpha-MSH), a potent anti-inflammatory cytokine in an ischaemic acute renal failure (ARF) rat model. We also examined neutrophil infiltration together with intercellular adhesion molecule-1 (ICAM-1) expression because of their possible involvement in apoptosis due to their ability to release various inflammatory cytokines and reactive oxygen species. METHODS: After unilateral nephrectomy in female Sprague-Dawley rats, the renal artery of the contralateral kidney was clamped for 40 min and reperfused. alpha-MSH or vehicle was injected intraperitoneally immediately after reperfusion and at 1, 6, or 24 h after reperfusion. The expression of Fas and Fas ligand was studied by western blot analysis and semiquantitative reverse transcription polymerase chain reaction (RT-PCR). Apoptosis was assessed by the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling (TUNEL) method, and neutrophil infiltration by naphthol AS-D chloracetate staining. The degree of apoptosis, neutrophil infiltration, and Fas and Fas ligand, and ICAM-1 expression, as well as biochemical and histological data were compared between the alpha-MSH and the vehicle-treated groups. RESULTS: Intraperitoneally administered alpha-MSH significantly reduced renal injury, measured by blood urea nitrogen (BUN) and creatinine and by the degree of tubular necrosis (109.6+/-7.1/54.7+/-3.1 mg/dl for BUN, and 1.6+/-0.2/1.03+/-0.06 mg/dl for creatinine 24 h after ischaemia) (5.4+/-0.8/2.6+/-0.3 for injury score 24 h after ischaemia). Ischaemia caused an increase in Fas and Fas ligand expression and was accompanied by morphological evidence of apoptosis. alpha-MSH significantly reduced the degree of apoptosis, as well as Fas and Fas ligand expression (mean apoptotic cell number, 41.7+/-3.5/14.2+/-2.2 per x200 field at 24 h after ischaemia. Fas protein expression: sham, 1409+/-159 DI (densitometric index); vehicle/alpha-MSH, 2818+/-635/1306+/-321 DI at 24 h and 5542+/-799/2867+/-455 DI at 72 h after ischaemia. Fas ligand protein expression: sham, 1221+/-181 DI; vehicle/alpha-MSH, 2590+/-85/1279+/-169 DI at 4 h, 4376+/-268/2432+/-369 DI at 24 h and 5200+/-648/2253.7+/-1104 DI at 72 h after ischaemia). Neutrophil infiltration and ICAM-1 expression were also significantly reduced in alpha-MSH group (neutrophil infiltration: vehicle/ alpha-MSH, 5.05+/-1.8/1.59+/-0.4) (ICAM-1 expression, vehicle/alpha-MSH 0.46+/-0.21/0.29+/-0.19). CONCLUSION: These results suggest that apoptosis clearly contributes to tubular cell loss in ischaemia/reperfusion (I/R) injury possibly by neutrophil-mediated pathways or an increase in Fas-Fas ligand expression. The observed beneficial effect of alpha-MSH could be related to these mechanisms.

Reaction monitoring of succinylation of collagen with matrix-assisted laser desorption/ionization mass spectrometry.

Succinylated collagen was synthesized by the reaction of collagen with succinic anhydride under basic conditions for one hour. Using the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) technique, the reaction products were directly identified without multi-step separation processes. MALDI-MS monitored the reaction more accurately than the conventional method of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). From the change in molecular mass during the reaction, it is observed that about 28 succinyl groups are attached to the collagen strand.

Thermophilic sulphate and sulphite reduction in lab-scale gas-lift reactors using H(2) and CO(2) as energy and carbon source.

Feasibility of thermophilic (55 degrees C) sulphate and sulphite reduction with H(2) and CO(2) gas-mixtures was studied in gas-lift reactors, which contained pumice particles as carrier material. Particular attention was paid to biomass retention and the competition between hydrogenotrophic sulphate-reducers and other hydrogenotrophic thermophiles. A model medium with defined mineral nutrients was used.The results of the experiments clearly demonstrate that sulphate conversion rates up to 7.5 g SO(4) (2-)/L per day can be achieved. With sulphite, a reduction rate of 3.7 g S/L per day was obtained, which equals a sulphate conversion rate of 11.1 g SO(4) (2-)/L per day. Under the applied conditions, a strong competition for hydrogen between hydrogenotrophic sulphate-reducers, tentatively designated as Desulfotomaculum sp., and hydrogenotrophic methanogens was observed. The outcome of the competition could not be predicted. Growth of the mixed culture was totally inhibited at an H(2)S concentration of 250 mg/L. Poor attachment of sulphate-reducing bacteria was observed in all experiments. The biomass concentration did not exceed 1.2 g/L, despite the presence of 50 g/L of pumice. The reason for this phenomenon remains to be understood. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 807-814, 1997.

Potentiometric properties of ion-selective electrode membranes based on segmented polyether urethane matrices.

Potentiometric responses of polyurethane (PU)-based membranes containing valinomycin and varying amounts of plasticizer (DOA) and/or lipophilic additive (KTpClPB) were examined as a function of soft segment [poly(tetramethylene ether glycol)] contents in aromatic diisocyanate-based PU matrices. Upon increasing the weight percentages (w(soft)) of soft segments, which in part behave like a built-in plasticizer, providing the matrices with rubbery structure (glass transition temperature below -58 °C), the amounts of DOA and/or KTpClPB necessary to result in near-Nerntian response (e.g., slope > 50 mV/decade) to potassium were substantially lowered. The apparent effect of adding plasticizer to PU-based membranes was comparable to that resulting from an increase of free carrier concentration in normal PVC-based membranes. Owing to the chemical interaction between mobile anionic sites and urethane chains, plasticizer-free PU membranes could be prepared with the PU matrices with high soft segment contents (w(soft) ≥ 60 wt %). PUs composed of 60 ≤ w(soft) < 80 wt % were recommended as the matrix for fabricating ISE membranes with no or low plasticizer content.