Pseudoparadoxical dissociation of cerebral oxygen saturation and cerebral blood flow velocity after acupuncture in a woman with cerebrovascular dementia: a case report

Acupuncture can increase both cerebral oxygen saturation and cerebral blood flow velocity. We describe a 77-year-old woman with cerebrovascular dementia in whom acupuncture reproducibly induced an increase of blood flow velocity but a decrease of regional oxygen saturation. At four of 11 acupuncture sessions, blood flow velocity was measured in the middle cerebral artery with transcranial Doppler sonography and cerebral regional oxygen saturation (rSO(2)) with transcranial near infrared spectroscopy. Cerebral blood flow velocity increased by an average of 20% (range: 7-27%) at all four study points whereas rSO(2) consistently decreased by an average of 7% (range: 4-13%). Clinical status and cognitive function improved. These findings in a patient with vascular dementia may suggest increased oxygen extraction by activated neuronal structures.     

Dopamine transporter: involvement in selective dopaminergic neurotoxicity and degeneration

The carrier molecule that transports dopamine (DA) into dopamine neurons by an electrogenic, Na(+)- and Cl(-)-transport-coupled mechanism is known as the dopamine transporter (DAT). This uptake system is exclusively expressed in DA neurons with significantly higher levels of DAT expression in cells of the substantia nigra pars compacta than those of the ventral tegmental area and arcuate hypothalamic neurons. The expression density of DAT strongly correlates with the extent of DA cell loss in Parkinson's disease (PD). There are also DAT gene polymorphisms associated with PD. These data suggest a role of the DAT in the pathogenesis of PD. Though selective for its respective neurotransmitter, the DAT can also transport synthetic/natural analogues of the transmitter. Should such compounds interact with vital intracellular structures, their penetration into the neuron might have significant consequences. This sequence of toxic events could indeed demonstrated for the synthetic toxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which produces selective degeneration of DA neurons characteristic of PD. Dopaminergic toxicity of its active metabolite 1-methyl-4-pyridinium (MPP(+)) is mediated by the DAT through accumulation into DA neurons, where it inhibits mitochondrial complex I activity. Various endogenous and exogenous heterocyclic molecules, which are structurally related to MPTP/MPP(+), such as isoquinolines and beta-carbolines, have been reported to exhibit similar toxic properties on DA cells, which are conferred by their uptake by the DAT. Taken together, there is large body of evidence from morphological, molecular biological and toxicological studies indicating that the DAT might be responsible for the selectivity of DA cell death in PD.     

Linking the synapse to the cytoskeleton: a breath-taking role for microfilaments

Cytoskeletal elements, in particular microtubules and microfilaments, are essential players in a large variety of phenomena requiring cellular and intracellular motility. To name but a few, they are intimately involved in determining cell shape and adhesion, establishment and maintenance of polarity, locomotion and organelle transport in all eukaryotic cells, including neurons. Here, we would like to focus on the synapse in the vertebrate central nervous system, proposing a model for a specific dialogue between neuronal microfilaments and other protein components in neurotransmission and synaptic plasticity.     

Specific downregulation and mistargeting of the lipid raft-associated protein MAL in a glycolipid storage disorder

Metachromatic leukodystrophy (MLD) is a lysosomal lipid storage disease caused by arylsulfatase A deficiency. In MLD patients the sphingolipid sulfatide increasingly accumulates leading to progressive demyelination. We have analysed arylsulfatase A-deficient mice, a MLD mouse model, and we show that accumulation of sulfatide is not restricted to the lysosomal compartment but also occurs in myelin itself. Although, this sulfatide storage did not affect the overall composition of most myelin proteins, it specifically caused a severe reduction of MAL. This demonstrates a regulatory link between sulfatide accumulation and MAL expression and indicates the existence of regulatory mechanisms between lipid and myelin protein synthesis in oligodendrocytes. In addition, in cultured renal epithelial cells, sulfatide accumulation diverts MAL to the late endosomal/lysosomal compartment and thus also affects the intracellular distribution of MAL. The specific reduction and mistargeting of MAL protein as a reaction to sulfatide overload may contribute to the pathogenic mechanisms in metachromatic leukodystrophy.     

Neural and behavioral responses to tryptophan depletion in unmedicated patients with remitted major depressive disorder and controls

CONTEXT: An instructive paradigm for investigating the relationship between brain serotonin function and major depressive disorder (MDD) is the response to tryptophan depletion (TD) induced by oral loading with all essential amino acids except the serotonin precursor tryptophan. OBJECTIVE: To determine whether serotonin dysfunction represents a trait abnormality in MDD in the context of specific neural circuitry abnormalities involved in the pathogenesis of MDD. DESIGN: Randomized double-blind crossover study. SETTING: Outpatient clinic. PARTICIPANTS: Twenty-seven medication-free patients with remitted MDD (18 women and 9 men; mean +/- SD age, 39.8 +/- 12.7 years) and 19 controls (10 women and 9 men; mean +/- SD age, 34.4 +/- 11.5 years). INTERVENTIONS: We induced TD by administering capsules containing an amino acid mixture without tryptophan. Sham depletion used identical capsules containing hydrous lactose. Fluorodeoxyglucose F 18 positron emission tomography studies were performed 6 hours after TD. Magnetic resonance images were obtained for all participants. MAIN OUTCOME MEASURES: Quantitative positron emission tomography of regional cerebral glucose utilization to study the neural effects of sham depletion and TD. Behavioral assessments used a modified (24-item) version of the Hamilton Depression Rating Scale. RESULTS: Tryptophan depletion induced a transient return of depressive symptoms in patients with remitted MDD but not in controls (P<.001). Compared with sham depletion, TD was associated with an increase in regional cerebral glucose utilization in the orbitofrontal cortex, medial thalamus, anterior and posterior cingulate cortices, and ventral striatum in patients with remitted MDD but not in controls. CONCLUSION: The pattern of TD-induced regional cerebral glucose utilization changes in patients with remitted MDD suggests that TD unmasks a disease-specific, serotonin system-related trait dysfunction and identifies a circuit that probably plays a key role in the pathogenesis of MDD.     

Atypische Enzephalitis eines 20-jährigen Wehrpflichtigen

Zusammenfassung Wir berichten über einen Patienten mit unspezifischen Zeichen einer ZNS-Infektion, die sich im Verlauf neben einem bronchopulmonalen Infekt als weitere Organmanifestation einer Mycoplasma-pneumoniae-Infektion herausstellte. Unter adäquater Antibiotikatherapie war der weitere Verlauf trotz des anfangs äußerst ungünstigen klinischen Befunds sehr gut. Pathophysiologische, differenzialdiagnostische und therapeutische Implikationen des Falls werden diskutiert und Richtlinien für die Diagnose vorgeschlagen.     

Insulin and dexamethasone inhibit TGF-beta-induced apoptosis of hepatoma cells upstream of the caspase activation cascade

Insulin and dexamethasone are potent inhibitors of apoptosis induced by transforming growth factor-beta1 (TGF-beta) in hepatoma cells. Using FTO-2B rat hepatoma cells, we determined whether the anti-apoptotic effects of these agents result from interference within or upstream of the TGF-beta-induced caspase cascade. Activation of different initiator and effector caspases, Bax and Bcl-xL expression, mitochondrial cytochrome c release and activation of PKB/Akt were analyzed by use of synthetic caspase substrates and Western blotting, respectively. TGF-beta-induced apoptosis was characterized by release of cytochrome c from mitochondria and activation of caspases-3, -7, -8 and -9. These effects were observable as early as 8-12 h after start of treatment and increased with time of observation. Inhibition of TGF-beta-induced apoptosis by insulin and dexamethasone was paralleled by a strong reduction of caspase-3-like activity. Caspase-8 activation was almost completely suppressed by these agents, and caspase-9 activity was decreased to levels within or slightly above unstimulated control cells. In addition, cytochrome c release from mitochondria was efficiently repressed, which was associated with upregulation of Bcl-xL by dexamethasone and activation of PKB/Akt by insulin. Thus, both anti-apoptotic compounds exert their inhibitory effects through modulation of anti-apoptotic signalling pathways involved in regulation of cytochrome c release and activation of the caspase machinery.     

Medical care for individual patients: concepts beyond evidence-based medicine

Todays evidence-based medicine has brought the practicing physician a vast amount of statistical evidence from which various stakeholders in the healthcare system obtain their arguments for and against the use of new therapies. Physicians assume an obligation to prescribe these new treatment options for their patients, firstly because of their eagerness to provide the best medicine, and secondly because of their fear of litigations. On looking at the published data, however, we have observed that the arguments for saving lives with a new treatment are not always supported by the underlying data. Sometimes the data show that the effect of treatment, in real terms, is only a relatively small gain in life-time prolongation. It is concluded that EBM-based concepts such as NNT (number needed to treat), absolute risk and relative risk fall short in ensuring real benefit for the patient. We have, therefore, put forward a mathematic model which takes into account the benefit of a treatment for the individual patient in terms of expected gain in lifetime duration. This model is readily applicable to published results on the clinical effects of a medical therapy and gives the practicing physician a useful tool for deciding whether to administer a medical therapy or not. By looking at the duration of treatment and the individual gain in lifetime expected, we have derived an effectiveness coefficient which can be used to categorize medical treatments into highly effective (close to 100%) and not effective (< 5%), and at the same time arrive at a cost-benefit analysis of the treatment in question. These simple concepts will help physicians and individual patients to make informed decisions based only on those medical therapies which are proven and appropriate. The model we have developed provides a new perspective in therapy for the individual patient using medicines that constitute a rational therapy i.e. a therapy that makes "sense" (sense-orientated medicine = SOM).     

TBE booster immunization according to the rapid immunization schedule: are 3-year booster intervals really necessary?

In order to evaluate the need for further booster immunizations, 222 subjects aged 20-52 years, who had received the first booster dose with a new tick-borne encephalitis (TBE) vaccine in a preceding study, were invited for a serological follow-up. A total of 191 and 182 adult subjects were analyzed for the persistence of neutralizing TBE antibodies at 1 and 2 years following the first booster immunization, respectively. Both serological follow-ups revealed high levels of neutralizing TBE antibodies in more than 99% of subjects. Although an expected decline of the respective geometric mean titers (GMTs) was noted after booster immunization, the titers were still far above the values noted after primary immunization at the 2-year follow-up. The kinetic curve clearly indicates a longer persistence of neutralizing TBE antibodies than currently expected. To conclude, these results suggest that the administration of a further booster dose 3 years after the first one (according to current recommendations) does not seem to be necessary in this study population.