Apoptosis of microglia and oligodendrocytes after spinal cord contusion in rats

Following spinal cord contusion in the rat, apoptosis has been observed in the white matter for long distances remote from the center of the lesion and is primarily associated with degenerating fiber tracts. We have previously reported that many of the apoptotic cells are oligodendrocytes. Here we show that the oligodendrocyte death is maximal at 8 days postinjury and suggest that loss of oligodendrocytes may result in demyelination of axons that have survived the initial trauma. There are two mechanisms that may account for the observed oligodendrocyte apoptosis. The apoptotic cell death may result from the loss of trophic support after axonal degeneration or it may be the consequence of microglial activation. The hypothesis that oligodendrocyte apoptosis is secondary to microglial activation is supported by our observations of microglia with an activated morphology in the same regions as apoptosis and apparent contact between some of the apoptotic oligodendrocytes and microglial processes. In addition to oligodendrocyte apoptosis, a subpopulation of microglia appears to be susceptible to apoptotic cell death as well, as evidenced by the presence of apoptotic bodies in OX42 immunopositive profiles. Thus, the population of apoptotic cells following spinal cord contusion is comprised of oligodendrocytes and putative phagocytic microglia or macrophages. Given the delayed time course of oligodendrocyte death, the apoptotic death of oligodendrocytes may be amenable to pharmacological intervention with subsequent improvement in functional recovery.     

Primary intraosseous meningioma of the vault

Primitive intra-osseous meningioma is a rare benign tumor. We report a case with a temporal localization and antro-attical extension into the petrous bone.     

Laser photocoagulation for macular soft drusen. Updated results

PURPOSE: To update the results of a study on the disappearance of macular soft drusen after laser treatment in the natural evolution of age-related macular degeneration. METHODS: A total of 46 patients with confluent soft drusen and pigmentary changes were studied prospectively. Group 1 was composed of 30 patients with bilateral drusen; the authors randomly assigned one eye of each patient for treatment and the fellow eye for the control. In 16 patients a choroidal neovascular membrane was present in one eye, and treatment was applied to the fellow eye (group 2). Argon green laser treatment was applied directly to the soft drusen in the temporal macula. RESULTS: All treated drusen disappeared in a mean of 3.5 months after treatment, and untreated drusen disappeared in all but three patients in an average of 8.5 months. After an average period of 3 years, only one control eye and none of the treated eyes in group 1 developed a choroidal neovascular membrane (P = 0.500). In group 2, neovascularization occurred in 18% of the patients. The initial improvement in Snellen acuity after subfoveal drusen disappearance diminished as a consequence of cataract progression. CONCLUSIONS: Although no definitive conclusions should be made because of the small number of patients studied, results seem to show that this treatment does not reduce the risk of choroidal neovascularization in the treated eye of patients with a history of exudative disease in the fellow eye. It may be effective in patients with high-risk bilateral soft drusen, that is, in less advanced stages of the disease.     

The gender difference on the Mental Rotations test is not due to performance factors

We have studied the antibacterial activity of different concentrations of 0.005-2% lidocaine (lignocaine) in mixtures with Diprivan (propofol), against micro-organisms commonly implicated in sepsis as a result of extrinsically contaminated Diprivan. Bacterial colony counts were reduced progressively with increasing concentrations of lidocaine. Bacteriostatic and bactericidal concentrations of lidocaine were 0.2-2%. Lidocaine 2% was not bactericidal for one of the seven organisms tested. By inhibiting bacterial replication, lidocaine, when added to Diprivan to reduce pain on injection, may possibly reduce the harmful consequences if extrinsic contamination occurs.     

Cloning, sequencing, and expression of the structural genes for the cytochrome and flavoprotein subunits of p-cresol methylhydroxylase from two strains of Pseudomonas putida

The structural genes for the flavoprotein subunit and cytochrome c subunit of p-cresol (4-methylphenol) methylhydroxylase (PCMH) from Pseudomonas putida NCIMB 9869 (National Collection of Industrial and Marine Bacteria, Aberdeen, Scotland) and P. putida NCIMB 9866 were cloned and sequenced. The genes from P.putida NCIMB 9869 were for the plasmid-encoded A form of PCMH, and the genes from P.putida NCIMB 9866 were also plasmid encoded. The nucleotide sequences of the two flavoprotein genes from P.putida NCIMB 9869 and P.putida NCIMB 9866 (pchF69A and pchF66, respectively) were the same except for 5 bases out of 1,584, and the translated amino acid sequences were identical. The nucleotide sequences of the genes for the cytochrome subunits of PCMH from the two bacteria (pchC69A and pchC66) varied by a single nucleotide in their 303-base sequences, and the translated amino acid sequences differed by a single residue at position 41 (Asp in PchC69A and Ala in PchC66). Both cytochromes had 21-residue signal sequences, as expected for periplasmic proteins, and these sequences were identical. On the other hand, no signal sequences were found for the flavoproteins.pchF69A and pchC69A were expressed, separately or together, in Escherichia coli JM109 and P.putida RA4007, with active PCMH produced in both bacteria. The E. coli-expressed flavocytochrome was purified. Our studies indicated that the E.coli-expressed subunits were identical to the subunits expressed in P.putida NCIMB 9869: molecular weights, isoelectric points, UV-visible spectra, and steady-state kinetic parameters were the same for the two sets of proteins. The subunits readily associated upon mixing two crude extracts of E.coli, one extract containing PchC69A and the other containing PchF69A. The courses of association of PchC69A and PchF69A were essentially identical for pure E. coli-expressed subunits and pure P. putida 9869-expressed subunits. E. coli-expressed PchC69A and PchF69A contained covalently bound heme and covalently bound flavin adenine dinucleotide, respectively, as the proteins expressed in nature.     

Intraventricular atrial natriuretic peptide for acute intracranial hypertension

The effect of intraventricular atrial natriuretic peptide (ANP) on elevated intracranial pressure (ICP) was evaluated in a rodent model of global ischemia and reperfusion. ANP administration into the lateral ventricle 30 minutes after reperfusion statistically significantly reduced ICP compared with both vehicle treated animals (p < 0.001) and pretreatment pressures (p < 0.001). The ICP effects of ANP did not coincide with specific changes in regional perfusion parameters measured by laser-Doppler flowmetry. Two different vehicles for ANP were used to verify that the changes in ICP observed were independent of the sodium content administered in the vehicle. Based on the reductions observed in ICP, ANP deserves further evaluation as a treatment modality for the acute elevations in ICP associated with ischemic brain injury.