[A simple and cosmetically ideal method large cranioplasty]

Repair of large skull defects is indicated as well to improve cosmetic as to protect the brain. A simply and easy to use procedure for exact duplication of cranial bone flaps used in cranioplasty is described. The original bone flap must be available to produce the definitive prosthesis.

Short-term prognostic factors in lumbar disc surgery: the low back prognostic score is of predictive value

In order to determine prognostic factors of lumbar disc surgery, we examined 107 patients who were conventionally operated on in a prospective, consecutive study. We analysed general data, the case history, the neurological examination at admission and all data from imaging examinations and therapy. In addition, all patients received a questionnaire based on the Low Back Outcome Score [9, 10]. The patients were re-examined after 2-8 months (103 days mean). According to their ratings on a pain grading scale, the patients were divided into a group with favorable and another with unfavorable results. These groups were analysed in relation to the patients' initial condition. At follow up, 88% of the patients had either completely recovered or their complaints had been relieved. According to the Low Back Outcome Score (LBOS), 64.5% went well. Used to evaluate the initial condition of the patients on admission the LBOS was able to predict favorable outcome in 68% and unfavorable outcome in 50%. To improve the prognostic value, we combined significant questions of the LBOS with the pain grading scale and significant prognostic factors to form a new prognostic score (Low Back Prognostic Score). With this new score we were able to predict a favorable outcome in 84% of our patients, and an unfavorable outcome in 71%. The Low Back Prognostic score seems to provide a sensitive method for predicting a favorable or unfavorable outcome for patients scheduled to undergo lumbar disc surgery.

Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) of intracranial lipomas

We show a detailed magnetic resonance (MR) examination of two rare pericallosa lipomas with a fat suppression imaging sequence and proton MR spectroscopy. For comparison, subcutaneous fat and lipids in glioblastomas were examined with H MR spectroscopy in vivo and ex vivo. Fat suppression makes the identification of lipomas simple. It is suggested that H MR spectroscopy shows no differences in the aliphatic chain length of lipoma and subcutaneous fat, whereas lipids in glioblastomas have a much shorter chain length. Chain length of fatty acids in lipoma measured with in vivo MR spectroscopy are in concordance with data from the literature.

The extraneuronal transporter for monoamine transmitters exists in cells derived from human central nervous system glia

From studies on sympathetically innervated peripheral tissues it is well known that both neuronal and non-neuronal transport systems contribute to the inactivation of released monoamine transmitters. The close proximity between synapses and glia cell processes in the CNS leads to the so far unresolved question whether non-neuronal transporters are involved in the inactivation of centrally released monamine transmitters such as noradrenaline, dopamine and 5-hydroxytryptamine. 1-Methyl-4-phenylpyridinium (MPP+) is a prototypical substrate of the extraneuronal monoamine transporter (uptake2). [3H]MPP+ was found to accumulate in various human glioma cell lines. [3H]MPP+ transport was characterized in more detail in HTZ146 human glioma cells. The Ki values of various compounds for the inhibition of initial rates of [3H]MPP+ transport into HTZ146 cells were closely correlated with known Ki values for the inhibition of the extraneuronal monoamine transporter (P < 0.01, r = 0.991, n = 7). The rank order of inhibitory potencies was decynium 22 > corticosterone > cyanine 863 > O-methylisoprenaline > quinine > clonidine > quinidine. [3H]MPP+ accumulation was investigated not only in various CNS tumour cell lines but also in primary cultures of human astrocytes and rat cerebral cortex slices. In all tested experimental systems, accumulation was sensitive to cyanine-related inhibitors of the extraneuronal monamine transporter. These findings suggest that the extraneuronal monamine transporter exists in glia cells. Furthermore, it was shown that MPP+ is able to make use of the extraneuronal monoamine transporter not only to enter but also to leave glia cells. This finding suggests that the extraneuronal monoamine transporter may play a key role in the mechanism of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxicity.

Extraneuronal uptake of noradrenaline in human tissue (uptake2)

The neurotransmitter, noradrenaline, is inactivated by active transport out of the synaptic cleft, either back into the adrenergic neurons (uptake1) or into extraneuronal cells (uptake2). Although experimental models clearly demonstrate uptake2 in various animal tissues, there are few reports of studies that demonstrate uptake2 in human tissue. Furthermore, uptake2 has never been described in human heart tissue. We demonstrated a reduction of 3H-noradrenaline uptake in human atrial and venous tissue and in rat atrial and ventricular tissue by O-methyl isoprenaline-a known inhibitor of uptake2. These results indicate that uptake2, as has been described in previous experimental models, does exist in humans and further, the results emphasize the importance of uptake2, since about 50% of exogenous noradrenaline is inactivated by uptake2 in the rat heart.

The neuronal transport mechanism for noradrenaline is not influenced by the ATP analogue ATP gamma S

Noradrenaline is taken up in noradrenergic neurones via a desipramine-sensitive transport system (uptake1). There are reports which describe the activity of uptake1 being increased by extracellular ATP and ATP gamma S. This was attributed to a protein kinase-mediated mechanism. We reevaluated this phenomenon since a modulation of uptake1 by extracellular ATP would be of great physiological relevance. In clonal rat pheochromocytoma cells (PC12) we determined the kinetic parameters, Km and Vmax, of noradrenaline transport in the absence and presence of ATP gamma S. The addition of 0.1 mumol/L ATP gamma S had no effect on initial rates of specific noradrenaline transport. Only a slightly increased non-specific noradrenaline flux in the presence of ATP gamma S could be observed. On the basis of our results, there is no evidence for the modulation of the uptake1 carrier by ATP gamma S.

The extraneuronal transport mechanism for noradrenaline (uptake2) avidly transports 1-methyl-4-phenylpyridinium (MPP+)

The corticosterone-sensitive extraneuronal transport mechanism for noradrenaline (uptake2) removes the neurotransmitter from the extracellular space. Recently, an experimental model for uptake2 has been introduced which is based on tissue culture techniques (human Caki-1 cells). The present study describes some properties of uptake2 in Caki-1 cells and introduces a new substrate, i.e., 1-methyl-4-phenylpyridinium (MPP+). Experiments on Caki-1 cells disclosed disadvantages of tritiated noradrenaline as substrate for the investigation of uptake2. The initial rate of 3H-noradrenaline transport [kin = 0.58 microliter/(mg protein.min)] was low compared with other cellular transport systems and intracellular noradrenaline was subject to rapid metabolism (kO-methylation = 0.54 min-1). The neurotoxin MPP+ was found to be a good substrate of uptake2. Initial rates of specific 3H-MPP+ transport into Caki-1 cells were saturable, the Km being 24 micromol/l and the Vmax being 420 pmol/(mg protein.min). The rate constant of specific inward transport was 34 times higher [19.6 microliters/(mg protein.min)] than that of 3H-noradrenaline. The ratio specific over non-specific transport was considerably higher for 3H-MPP+ (12.6) than for 3H-noradrenaline (3.0). 3H-MPP+ transport into Caki-1 cells was inhibited by various inhibitors of uptake2. The highly significant positive correlation (p less than 0.001, r = 0.986, n = 7) between the IC50's for the inhibition of the transport of 3H-noradrenaline and 3H-MPP+, respectively, proves the hypothesis that MPP+ enters Caki-1 cells via uptake2. 3H-MPP+ is taken up via uptake2 not only by Caki-1 cells but also by the isolated perfused rat heart which is another established model of uptake2.(ABSTRACT TRUNCATED AT 250 WORDS)