Towards a common language in neurosurgical outcome evaluation: the NEON (NEurosurgical Outcome Network) proposal

BACKGROUND

The aim of this study was to achieve a consensus on the minimum set of outcome measures and predictors to be used in the neurosurgical practice and on the timing of outcome assessment.

METHODS

A consensus building approach was employed. All neurosurgical departments in Lombardy (Italy) were invited to participate by the Carlo Besta Neurologic Institute IRCCS Foundation. Three workshops were organized during which a multidisciplinary group called Neurosurgical Outcome Network (NEON) was created and the methodology to select outcome measures, predictors, and timing of outcome assessment was established. Eight working groups were created for the different neurosurgical diseases (neuro-oncological, skull base, vascular, traumatic, spinal, peripheral nervous system, malformation, functional) and 8 workshops were organized to identify the outcome measures and predictors specific for each of the neurosurgical diseases based on the experts' clinical practice and the existing literature.

RESULTS

A total of 20 neurosurgical departments participated in this study. Specific outcome measures, predictors and the timing of outcome assessment were identified for each of the 8 neurosurgical diseases. Moreover, a list of variables common to all pathologies were identified by the NEON group as further data to be collected.

CONCLUSIONS

A consensus on the minimum set of outcome measures and predictors and the timing of outcome assessments for 8 neurosurgical diseases was achieved by a group of neurosurgeons of the Lombardy region, called NEON. These sets could be used in future studies for a more homogeneous data collection and as a starting point to reach further agreement also at national and international level.

A potentiometric and spectrofluorimetric approach to unravel inhibitory effects of semi- and thiosemicarbazones on mushroom tyrosinase activity

The inhibitory effects on mushrooms tyrosinase activity of some semi- and thiosemicarbazones were investigated. While the semicarbazones are inactive, the thiosemicarbazones are, in general, more active than the reference (kojic acid, IC₅₀ = 70 μM), with maximum activity obtained with benzaldehyde thiosemicarbazone (IC₅₀ = 7 μM). These inhibitors probably act by coordination of the copper(II) metal ions in the active site of tyrosinase: effectively, potentiometric studies conducted in water solutions confirm that the most active thiosemicarbazone is a good ligand for copper(II) ions. The tyrosinase CD spectra do not show any significant difference by addition of an inhibitor or an inactive compound. On the contrary, interesting results were obtained by spectrofluorimetric titrations of mushrooms tyrosinase aqueous solutions with some of the investigated compounds, giving helpful information about possible mechanism of action. The thiosemicarbazones here reported are not cytotoxic on human fibroblasts and do not activate cells in a pro-inflammatory way.

Posterolateral transpedicular approach for ventrally seated cervicothoracic spinal cord lesions: how I do it

BACKGROUND

Surgical exposure of lower cervical and upper thoracic intradural extramedullary lesions located along the ventral medulla are among the most complexes to address in spinal surgery, and their surgical removal carries a high risk.

METHODS

We describe the surgical steps of a posterolateral transpedicular approach for resection of an intradural extramedullary lesion located anterolaterally at C7-T1 level.

CONCLUSIONS

A posterolateral transpedicular approach is a safe and efficient surgical corridor to explore the ventral spinal cord and to have a direct access to lower cervical-upper thoracic lesions without the extensive manipulation of the spinal cord and the spine instability.

UniPR129 is a competitive small molecule Eph-ephrin antagonist blocking in vitro angiogenesis at low micromolar concentrations

BACKGROUND AND PURPOSE

The Eph receptor tyrosine kinases and their ephrin ligands are key players in tumorigenesis and many reports have correlated changes in their expression with a poor clinical prognosis in many solid tumours. Agents targeting the Eph-ephrin system might emerge as new tools useful for the inhibition of different components of cancer progression. Even if different classes of small molecules targeting Eph-ephrin interactions have been reported, their use is hampered by poor chemical stability and low potency. Stable and potent ligands are crucial to achieve robust pharmacological performance.

EXPERIMENTAL APPROACH

UniPR129 (the L-homo-Trp conjugate of lithocholic acid) was designed by means of computational methods, synthetized and tested for its ability to inhibit the interaction between the EphA2 receptor and the ephrin-A1 ligand in an elisa binding study. The ability of UniPR129 to disrupt EphA2-ephrin-A1 interaction was functionally evaluated in a prostate adenocarcinoma cell line and its anti-angiogenic effect was tested in vitro using cultures of HUVECs.

KEY RESULTS

UniPR129 disrupted EphA2-ephrin-A1 interaction with Ki = 370 nM in an elisa binding assay and with low micromolar potency in cellular functional assays, including inhibition of EphA2 activation, inhibition of PC3 cell rounding and disruption of in vitro angiogenesis, without cytotoxic effects.

CONCLUSIONS AND IMPLICATIONS

The discovery of UniPR129 represents not only a major advance in potency compared with the existing Eph-ephrin antagonists but also an improvement in terms of cytotoxicity, making this molecule a useful pharmacological tool and a promising lead compound.

Novel mixed ligand technetium complexes as 5-HT1A receptor imaging agents

The synthesis, characterization and biological evaluation of two novel 3 + 1 mixed ligand 99mTc-complexes, bearing the 1-(2-methoxyphenylpiperazine) moiety, a fragment of the true 5-HT1A antagonist WAY 100635, is reported. Complexes at tracer level 99mTcO[(CH3CH2)2NCH2CH2N(CH2CH2S)2][o-CH3OC6H4N(CH2CH2)2NCH2CH2S], 99mTc-1, and 99mTcO[((CH3)2CH)2NCH2CH2N(CH2CH2S)2][o-CH3OC6H4N (CH2CH2)2NCH2CH2S], 99mTc-2, were prepared using 99mTc-glucoheptonate as precursor. For structural characterization, the analogous oxorhenium complexes, Re-1 and Re-2, were prepared by ligand exchange reaction using ReOCl3(PPh3)2 as precursor, and characterized by elemental analysis and spectroscopic methods. Complex Re-1 was further characterized by crystallographic analysis. Labeling was performed with high yield (>85%) and radiochemical purity (>90%) using very low ligand concentration. The structure of 99mTc complexes was established by comparative HPLC using the well-characterized oxorhenium analogues as references. In vitro binding assays demonstrated the affinity of these complexes for 5-HT1A receptors (IC50 : 67 and 45 nM for Re-1 and Re-2 respectively). Biological studies in mice showed the ability of 99mTc-1 and 99mTc-2 complexes to cross the intact blood-brain barrier (1.4 and 0.9% dose/g, respectively at 1 min post-inj.). The distribution of these complexes in various regions in rat brain is inhomogeneous. The highest ratio between areas reach and poor in 5-HT1A receptors was calculated for complex Tc-1 at 60 min p.i. (hippocampus/cerebellum = 1.7).

Synthesis and in vitro anthelmintic activity against Nippostrongylus brasiliensis of new 2-amino-4-hydroxy-delta-valerolactam derivatives

The synthesis of a series of 2-amino-4-hydroxy-delta-valerolactam derivatives is described (compounds 4 to 10). These compounds showed a high anthelmintic in vitro activity against the Nippostrongylus brasiliensis model.

Interaction of DAPI with pepsin as a function of pH and ionic strength

The fluorescent probe 4',6-diamidino-2-phenylindole (DAPI), extensively used with nucleic acids, has also recently been used with membranes and proteins (Favilla et al., Biophys. Chem., 46 (1993) 217-226 and Mazzini et al., Biophys. Chem. 52 (1994) 145-156, respectively). The spectroscopic changes of DAPI observed, namely a considerable enhancement of fluorescence, induced circular dichroism (CD) and absorbance spectral shifts, have been exploited to study the binding of this dye to both native and alkali denatured pepsin. Fluorescence and CD titrations show that nearly two molecules of DAPI bind to either native or alkali denatured pepsin with pH and ionic strength dependent Kd values, whereas absorbance titrations evidentiate an interaction characterized by a lower affinity and a larger number of binding sites. Therefore two kinds of interaction are proposed: a specific one, involving both hydrophobic and electrostatic forces; and a non-specific one, involving surface protein negative charges only. Finally, the behaviour of DAPI as a competitive inhibitor and the remarkable effect of pepstatin A, a specific inhibitor of pepsin, on both the CD and fluorescence spectra of DAPI in the presence of pepsin, show the involvement of the protein active site in the interaction.

A field comparison of three neutron moisture meters

A study was undertaken to compare 3 neutron moisture meters (NMMs) over a range of counting times on 2 soil types in north-westem Victoria. The meters were a Pitman Wallingford 225 (WAL225), a Campbell Pacific Nuclear 503 (CPN503), and a Campbell Pacific Nuclear 501DR (CPN501). The soil types were a grey self-mulching clay and a solonised brown soil (sandy loam). The 3 NMMs exhibited different count rates in water, from 242 to 2645 counts per second. It was necessary to increase the counting time of CPN501 to 64 s to achieve a comparable performance to WAL225 at 16 s. Over the 15-month experiment, standard counts remained relatively constant for WAL225 and CPN501, but CPN503 showed pronounced variation. In field calibrations, the inclusion of depth (as a separate variable to account for neutron absorbing gradients in the soil profile) made significant improvement to the regression of all NMMs irrespective of counting time. No improvements in the calibration were achieved using density corrections from core samples for individual layers. On both soil types, WAL225 and CPN503 performed similarly to each other, with very similar residual mean squares and coefficients of determination. On the grey clay, WAL225 and CPN503 explained 77 and 88% of the variation in soil water content, respectively. CPN501 performed poorly, even with a 64 s counting time, and explained only 52% of the variation when depth was included. When depth was excluded this fell to 25%. On the sandy loam, WAL225 and CPN503 explained 76 and 74%, respectively, of the variation in soil water content. CPN501 again performed poorly with a 64 s counting time, accounting for 65% of the variation when depth was included and 33% with depth excluded. Examples of poor calibrations or none at all in water use studies are discussed and typical errors are demonstrated.

Cropping practices in the Victorian Mallee. 1. Effect of direct drilling and stubble retention on the water economy and yield of wheat

Two experiments were conducted at the Mallee Research Station, Walpeup, between 1985 and 1989 to evaluate the impact of conservation farming practices on wheat yields. The first experiment compared wheat crops established by direct drilling into a chemical fallow with those conventionally sown into a cultivated fallow. Over the 5 years, yields ranged from 1.31 to 3.24 t/ha, and there was no reduction in crop yield associated with chemical fallowing and direct drilling compared with the cultivated fallow. There was also no significant effect of the chemical fallow on the amount of water conserved in the soil at sowing, at depth 0-100 cm; the range was 206-274 mm water. The second experiment from 1987 to 1989 examined the effect of maintaining 4 rates of stubble (0, 0.5, 1.0, 2.0 t/ha) on the surface of a conventionally cultivated long fallow. Stubble maintained at 2 t/ha increased the amount of water stored in the soil at sowing, at depth 0-140 cm, by 16 mm in 1 year of 3. This increase in soil water availability was not reflected in increased crop yield. These findings indicate that erosion control and potentially lower production costs associated with direct drilling and stubble retention can be achieved without loss of wheat yield in the Victorian Mallee.

Cropping practices in the Victorian Mallee. 2. Effect of long fallows on the water economy and the yield of wheat

Two experiments were conducted at the Mallee Research Station, Walpeup, between 1985 and 1989 to determine whether increases in wheat yield that occur after long fallows result from improvements in the supply and use of additional soil water conserved during the fallow. Although long fallows increased the amount of water stored in the soil at sowing (average 22 mm) and the yield of wheat (0.26 to 1.37 t/ha) in the first experiment, the results suggest no causal relationship between these increases. Improvements in wheat yield were attributed to increases in soil nitrogen availability and to control of cereal root diseases rather than to any increase in soil water conservation. This was confirmed in the second experiment, which was managed to ensure that nitrogen supply and cereal root diseases were not limiting crop production. Increases in soil water content at sowing resulting from long fallows did not result in higher wheat yields. This study suggests that long fallows cannot be justified on the basis of this increased soil water storage, as much of the additional soil water accumulated during the fallow period is stored in the lower part of the rootzone. Movement of this water below the rootzone during the growing season appears to be the main reason for the additional water stored at sowing, with long fallows failing to increase wheat growth and yield.

Rooting depth of wheat in the Victorian Mallee

In 1986 and 1987 wheat was sown in an experiment at the Mallee Research Station, Walpeup, at 2 times of sowing and with 3 rates of applied nitrogen. Soil cores were taken and trenches excavated to 1.5 m to measure wheat root growth and depth of rooting. Wheat roots penetrated to a maximum depth of 104 cm in crops sown in May, the optimum time of sowing for maximum yield, while delayed sowing reduced total root biomass and limited rooting depth to 73-83 cm. The application of nitrogen fertiliser did not affect either the rooting depth or growth and yield. Significant changes in total soil water content between sowing and harvest only occurred in 1987 with the early and late sown crops reducing the total soil water content by 47 and 99 mm respectively. In 1986, above average rainfall during the growing season caused the early sown crop to accumulate more water below 50 cm than the late sown crop. While total water use was increased only in 1986 with early sowing, crop water use efficiency and yield was greater in both years. The addition of nitrogen had no effect on crop water use or water use efficiency. A survey of wheat crops carried out in 1988 on 10 Mallee farms also found that shallow rooting is widespead. The field experiment and survey data show that, irrespective of sowing time, roots did not penetrate as far down the profile as might be expected, given reported rooting depths commonly in excess of 200 cm on similarly textured soils. This was shown to be associated with high soil pH and salt content. Poor rooting depth of wheat in this environment will restrict the use of stored water and accordingly, calls the practice of fallowing into question.