A new diagnostic method of spondylodiscitis. Magnetic resonance imaging

Twenty four patients who were hospitalized for a suspicion of spondylodiscitis were prospectively evaluated with magnetic resonance imaging (MRI), radiology and radionuclide studies. Fifteen patients had an infectious spondylodiscitis, four had a vertebral degenerative disease, four had a rheumaticus spondylodiscitis, one had a chemical spondylodiscitis. The microbiological examinations and the clinical development bore the diagnosis out. Seven patients underwent Indium 111 scanning. The results of this scanning were correlated with MRI results. The MRI was performed with a 0.35 T whole body superconducting unit using spin echo technique. All patients were studied in the sagittal plane with two pulse sequences and more often with a surface-coil: TR 500 msec./TE 28 msec. and TR 2,000 msec./TE 60 msec. In all cases of true infectious spondylodiscitis the MRI results finding were characteristics. On the image obtained with the TR 500 msec./TE 28 msec., there was a confluent decreased signal intensity from the vertebral bodies and the intervertebral disk space. On the image obtained with TR 2,000 msec./TE 60 msec. there was an increased signal intensity from the vertebral bodies and the intervertebral disk space. The other spondylodiscitis have given a different MRI imaging, it was a confluent decreased signal intensity from the vertebral bodies and the intervertebral disk space on the twice pulse sequences. different images were obtained during the evolution of the infectious: first we observed a modification of the vertebral signal then the typical image that we described then a normal signal of the vertebral bodies with a pathological signal from the intervertebral disk space at last a degenerative intervertebral disk.(ABSTRACT TRUNCATED AT 250 WORDS)     

Relationship between oxidative stress and essential hypertension.

This study investigated the association of blood pressure with blood oxidative stress-related parameters in normotensive and hypertensive subjects. A cross-sectional design was applied to 31 hypertensive patients and 35 healthy normotensive subjects. All subjects were men between the ages of 35 and 60 years. Exclusion criteria were obesity, dyslipidemia, diabetes mellitus, smoking and current use of any medication. All patients underwent 24-h ambulatory blood pressure monitoring and sampling of blood and urine. Antioxidant enzymes activity, reduced/oxidized glutathione ratio (GSH/GSSG), and lipid peroxidation (malondialdehyde) were determined in erythrocytes. Parameters measured in the plasma of test subjects were plasma antioxidant status, lipid peroxidation (8-isoprostane), plasma vitamin C and E, and the blood pressure modulators renin, aldosterone, endothelin-1 and homocysteine. Daytime systolic and diastolic blood pressures of hypertensives were negatively correlated with plasma antioxidant capacity (r=-0.46, p<0.009 and r=-0.48, p<0.007), plasma vitamin C levels (r=-0.53, p<0.003 and r=-0.44, p<0.02), erythrocyte activity of antioxidant enzymes, and erythrocyte GSH/GSSG ratio, with hypertensives showing higher levels of oxidative stress. Blood pressures showed a positive correlation with both plasma and urine 8-isoprostane. Neither plasma vitamin E nor the assessed blood pressure modulator levels showed significant differences between the groups or correlation with blood pressures. These findings demonstrate a strong association between blood pressure and some oxidative stress-related parameters and suggest a possible role of oxidative stress in the pathophysiology of essential hypertension.     

Online data visualization using the neural gas network.

A high-quality distance preserving output representation is provided to the neural gas (NG) network. The nonlinear mapping is determined concurrently along with the codebook vectors. The adaptation rule for codebook positions in the projection space minimizes a cost function that favors the trustworthy preservation of the local topology. The proposed visualization method, called OVI-NG, is an enhancement over curvilinear component analysis (CCA). The results show that the mapping quality obtained with OVI-NG outperforms the original CCA, in terms of the trustworthiness, continuity, topographic function and topology preservation measures.     

Hyperprolactinemia inhibits natural killer (NK) cell functionin vivo and its bromocriptine treatment not only corrects it but makes it more efficient

We studied NK cell function in eight patients with pathological hyperprolactinemia by measuring⁵¹Cr release by K562 cells exposed to their mononuclear cells and found it decreased compared to normal controls (P<0.01). Bromocriptine (BrC) treatment corrected NK function but also made it more efficient at 12:1 than at 25:1 or 50:1 effector:target ratios (ANOVA;P=0.01). The study of NK cell function in agarose revealed that its decrease in hyperprolactinemia is due to their low active binding to target cells, active killing, and recycling capacity. BrC tended to correct them but also increased recycling capacity to levels higher than those of controls (P<0.05). Sequential studies in three hyperprolactinemic patients before and after BrC showed correction of NK function within 1 week but its increased efficiency at the 12:1 effector:target ratio required 8 weeks. We conclude that hyperprolactinemia decreases NK cell function. BrC corrects this by decreasing prolactin levels but also makes NK function more efficient by increasing the capacity of NK cells to recycle after killing.     

Invaginated vein graft as nerve conduit: An experimental study

Vein grafts have been used for nerve repair in experimental and clinical studies. However, some concerns about their collapsability and the presence of valves which could block axonal growth have been put forth. We propose a modification to eliminate these potential problems by turning the vein inside out, obtaining an “invaginated” vein graft. We performed an experimental study on 61 adult Wistar rats, divided into 3 groups: control (non-operated) (n = 11); immediate repair, with 3 subgroups: invaginated vein graft (n = 10), vein graft (n = 10), and nerve graft (n = 10); and delayed repair, with 2 subgroups: invaginated vein graft (n = 10) and nerve graft (n = 10). Delayed repair was performed 3 to 4 weeks following division of the nerve. Electromyographical (EMG) assessment was performed in all operated animals at 2, 4, and 6 months after immediate reconstruction, and at 1 and 4 months after delayed repair. At the end of the study, all nerves were excised and a morphometric analysis was performed. We conclude that vein grafts are as useful as nerve grafts in immediate and delayed nerve repair, as there were no significant functional or histologic differences. We found no significant differences between invaginated vein grafts and non-invaginated vein grafts. However, electrophysiological results were slightly superior in the former. Regenerated axons were small, grouped in minifascicles with thin myelin sheaths. The venous adventitia did not interfere with axonal growth. © 1994 Wiley-Liss, Inc.     

Effect of Zr:Mo ratio on 99mTc generator performance based on zirconium molybdate gels.

Zirconium molybdate gels have shown to be viable alternatives for preparation of 99mTc generators using 99Mo produced by neutron activation. The aim of this work was to investigate the effect of the Zr:Mo molar ratio on the gel chemical structure and correlate it with the elution efficiency. A series of gels were prepared at Zr:Mo molar ratios from 0.5:1 to 2.3:1 and characterized by TGA, IR, XRD and UV. It was found that the variation of Zr:Mo ratio produces different polymolybdate arrangements on the octahedral units around to the zirconia which is mainly influenced by the water content. When the matrix molybdenum concentration was increased a lesser amount of water was found and the elution efficiencies were increased. However high elution efficiencies produce higher 99Mo breakthrough values. The gel formulation appears thus to be a compromise between the elution efficiency and the molybdenum breakthrough. The chemical-physical properties of these gels are presented and discussed.     

Application of factor VII-Sepharose affinity chromatography in the purification of human tissue factor apoprotein

Coagulation factor VII covalently coupled to Sepharose proved to be an effective binding ligand for human tissue factor apoprotein, the specific cofactor of factor VII for the activation of factor X and IX. This interaction is completely calcium-dependent and the calcium ions cannot be replaced by magnesium or barium ions. The binding of the apoprotein to immobilized factor VII seems to be independent of the presence of phospholipid. When factor VII-Sepharose column chromatography is combined with a mild extraction procedure, tissue factor apoprotein could be purified approximately 40,000-fold from an acetone powder of human brain. SDS-PAA gel electrophoresis revealed that with this simple purification scheme human tissue factor apoprotein can be purified to apparent homogeneity and that the apoprotein migrates at a molecular weight of 47,000. The isolated human protein is heterogeneously glycosylated; the two different forms of the apoprotein function as cofactor of factor VII in the activation of both factor X and factor IX.     

Effect of compression of spinal cord on brain rhythms

Electroencephalographic changes were studied in anaesthetised rats, subjecting them to the mechanical compression of spinal cord. The EEG waves that were studied-Alpha, Theta, and Delta. The changes in these waves and shift from one pattern to another after the compression of the spinal cord at the Lumbar level. These waves were subjected Fourier analysis. The results show remarkable changes in wave patterns and a shift in the dominating wave pattern. With 50% compression the EEG showed a slight increase in the amplitude in all three wave forms-- with Delta wave pattern being more dominant. At 100% compression there is a marked decrease in the Delta amplitude compared to normal. We tried to observe the changes in activity of the brain--the effects of spinal lesion and its relationship with tonic activity changes in EEG.