Visceral artery aneurysms—follow-up of 23 patients with 31 aneurysms after surgical or interventional therapy

Purpose  

Visceral artery aneurysms (VAA) are rare forms of vascular pathology, with an incidence of 0.1% to 0.2% in routine autopsies [1–4]. They frequently present as a life-threatening, often fatal, emergency, if associated with rupture and intra- or retroperitoneal bleeding. The clinical symptoms, natural history, and mortality of VAAs vary depending on the vessels involved. The mortality rates range from 8.5% up to 25% and, in pregnant women, up to 75% [1, 4, 6, 7]. A retrospective analysis of all VAAs diagnosed at our institution from 1991 to 2006 was performed. The presentation, management, and outcome of therapy was evaluated for each patient.     

Water-Free Sodium Accumulation

The widely accepted concept of body fluid and electrolyte homeostasis is that Na⁺ is restricted mainly to the extracellular fluid and K⁺ to the intracellular space, where both ions act to hold water and thereby control the extracellular and intracellular fluid volume by their osmotic activity. Na⁺ accumulation thus inevitably leads to water retention. The constancy of the extracellular volume is the task of the kidneys, which control the total body Na⁺ content. More recent data have questioned this traditional view, suggesting that large amounts of Na⁺ can be accumulated without accompanying water retention by osmotically inactive Na⁺ retention, or by osmotically neutral Na⁺/K⁺ exchange. Besides the control of the body Na⁺ content by the kidneys, redistribution of body electrolytes hence provides an extrarenal regulatory alternative in the maintenance of body fluid volume and blood pressure control.     

Cortical correlates of the basic and first harmonic frequency of Parkinsonian tremor

ObjectiveIt has been hypothesized that the basic and first harmonic frequency of Parkinsonian tremor are somewhat independent oscillations the biological basis of which remains unclear.MethodsWe recorded 64-channel EEG in parallel with EMG of the forearm muscles most affected by rest tremor in 21 PD patients. EMG power spectrum, corticomuscular coherence spectra and EEG power spectra for each EEG electrode were calculated. The dynamics of the coherence and relative EMG and EEG power at the basic (tremor) frequency were calculated by a sliding, overlapping window analysis. Corticomuscular delays and direction of interaction were analysed by the maximizing coherence method for narrow band signals.ResultsThe contralateral EEG electrodes with maximal coherence were different for the basic and first harmonic frequency. The dynamical coherence curves showed non-parallel time courses for the two frequencies. The mean EEG-EMG and EMG-EEG delays were all around 15–20 ms but significantly longer for the first harmonic than for the basic frequency.ConclusionsOur data indicate different cortical representations and corticomuscular interaction of the basic and first harmonic frequencies of Parkinsonian tremor.SignificanceSeparate central generators seem to contribute to the tremor via different pathways. Further studies on this complex tremor network are warranted.     

Missense exchanges in the <Emphasis Type=Italic>TTBK2</Emphasis> gene mutated in SCA11

The spinocerebellar ataxias (SCAs) with autosomal dominant inheritance are a clinically and genetically heterogeneous group of neurological disorders with overlapping as well as highly variable phenotypes primarily affecting the cerebellum. To date, 28 different loci have been identified. Nine SCAs are caused by repeat expansions; for 14 only the chromosomal localisation is known. Recently, two frameshift mutations in the tau tubulin kinase 2 gene (TTBK2) were reported to cause SCA11. To evaluate the frequency of mutations in the TTBK2 gene, we performed molecular genetic analyses in 49 unrelated familial cases with ataxia. Sequencing all coding exons revealed, amongst others, two novel missense exchanges at evolutionarily conserved amino acid positions. Although being unique in 98 alleles of ataxia patients, a disease causing effect can be excluded with high probability for both variations. This result demonstrates the challenges in diagnostic testing for SCA11.     

Myelinated nerve fibres in the subcortical white matter of cerebral hemispheres are preserved in alcoholic subjects

Previous studies have found that the primary change in the brain of chronic alcoholics is a selective loss of white matter in cerebral hemispheres. It is unknown whether the loss of white matter is due to alcohol-induced degeneration of axons in white matter, and this hypothesis has never been tested. We used a newly developed stereological method to investigate whether the length and diameter of myelinated fibres change in the subcortical white matter of male alcoholic subjects. We found no significant differences between control and alcoholic subjects with respect to the total volume, total length, and mean diameter of myelinated fibres in white matter. Our results do not find any support for the hypothesis that chronic alcoholic subjects may suffer from a degeneration of axons (myelinated fibres) in white matter in cerebral hemispheres.