Pohl's track screw for the surgical treatment of femoral neck fracture. Reliable surgical principle or obsolete method?

Pohl's hip screw--the classic form of a dynamic osteosynthesis--is an approved method in the treatment of the fracture of the femoral neck (lateral and pertrochanteric fractures). Between 1963 and 1983 over 200 patients were treated with Pohl's hip screw. At an averaged stay of 29 days in hospital half of them were rehabilitated. The mortality rate was 9.3%. More recent methods--e.g. the dynamic hip screw, propagated by AO--present more technical improvements but they are only variations of an old therapeutic principle proved over a generation.     

Neurological soft signs in schizophrenia.

A new scale for neurological soft signs (NSS) was constructed and consists of 17 items compiled from the literature. The scale was found to have a high internal reliability (Cronbach's alpha 0.83) and a high interrater reliability (0.88). According to the results of a factor analysis, NSS are covered by five factors: 'motor coordination', 'integrative functions', 'complex motor tasks', 'righ/left and spatial orientation' and 'hard signs'. Using this scale, the associations of NSS with clinical course and brain alterations were investigated. NSS varied with the clinical course and were significantly correlated with some BPRS subscales, in particular 'thought disorder'. In addition, the 'motor coordination' soft signs were found to correlate with morphological alterations in the basal ganglia.     

Intracranial ependymomas: Prognostic aspects

According to the grading of brain tumors as proposed by the WHO in 1976, out of 128 ependymomas 83 tumors could be classified as grade II and 38 as grade III Only seven subependymomas were benign and could be assigned to grade I.In contrast to most series known from the literature, 73 ependymomas were located above the tentorium and only 55 in the posterior cranial fossa. The grade of malignancy rised with an increased distance from the ventricular level.Macroscopically complete exstirpations were usually possible in hemispheric ependymomas, whereas tumors arising from the floor of the fourth ventricle often allowed only a partial removal. The operative mortality in the infratentorial group was more than twice as that in the supratentorial group.Postoperative survival was predominantly dependent on the histologic grade of malignancy. The five year survival rate without recurrence was 57.4% in grade II ependymomas as compared to 24.1% in grade III ependymomas. It could be improved by postoperative radiation therapy in both groups of malignancy. The almost identical longterm results indicate that even in less malignant ependymomas new tumor growth will occur later on.     

Prostacyclins are only weak antagonists of coronary vasospasm induced by authentic thromboxane A2 and serotonin

The actions of prostacyclin and its synthetic analog iloprost on the release and action of platelet-derived serotonin (5-HT) and thromboxane (TX) A2 were studied in vitro. Washed human platelet suspensions (WPS) (4 X 10(8) platelets/ml) were stimulated with arachidonic acid (AA) (30 mumol/L) and the incubate transferred into an organ bath containing bovine coronary arteries (BCA) in Krebs-Henseleit buffer supplemented with a mixture of blocking agents, including indomethacin. This resulted in a biphasic contraction of the coronary arteries, consisting of first, a TXA2-mediated response and second, a 5-HT-mediated response. The 5-HT-mediated reaction was dose-dependently inhibited by methysergide (IC50: 80 nmol/L). Treatment of the WPS with prostacyclin (PGI2) or iloprost prior to stimulation by AA resulted in a dose-dependent inhibition of the 5-HT-mediated contraction, due to inhibition of 5-HT release. The TXA2-mediated component, as well as the concentration of immunoreactive TXB2 in the bath medium, remained unchanged. Addition of PGI2 or iloprost to the BCA prior to transfer of stimulated WPS to the bath medium was followed by a dose-dependent inhibition of both phases. This, however, required concentrations of 100 nmol/L 5-HT and greater than 300 nmol/L TXA2 (IC50), which already produced a nearly complete direct relaxation of the vessel preparations (EC50: 30 nmol/L). It is concluded that a significant spasmolytic action of prostacyclins against platelet-derived vasoconstrictors in vivo might only be obtained at concentrations that already produce considerable direct effects on vessel tone.     

Kidney kinase network regulates renal ion cotransport

Protein kinases catalyze the phosphorylation of serine/threonine or tyrosine residues, which may directly alter a protein’s functional properties. Kinases can also regulate protein functions indirectly, for example, by controlling the composition and/or subcellular localization of members of multiprotein complexes that associate with the regulated protein. In this issue of the JCI, two separate studies by Weinman et al. and Yang et al. examine the second of these two modes of kinase-mediated regulation and demonstrate the effects of kinases on two Na⁺-driven renal cotransporters (see the related articles beginning on pages 3403 and 3412). Their results reveal important implications for phosphate and salt homeostasis, respectively.     

Spontaneous spinal epidural haematoma: a therapeutical challenge?

We report the conservative treatment of a spontaneous spinal epidural haematoma attending with acute extensive neurological deficits, which resolved spontaneously. Spontaneous remission of spontaneous spinal epidural haematoma with severe neurological deficit is rare in the literature. An 80 year old man was admitted to our hospital presenting sciatica followed by rapid development of paraparesis and cauda equina syndrome, which represents a neurosurgical emergency. Magnetic resonance imaging revealed a multilevel epidural haematoma from L1 to L5. During the initial diagnostic procedure the symptoms started to decline unexpectedly, so the surgical intervention could be withdrawn. Twenty four hours after admission the patient was almost free of symptoms, mobile, and continent. Awareness and high index of suspicion, and a willingness to seek the prompt help of the imaging department, are crucial to successful management before the opportunity to treat is lost.     

A simple method to check the dynamic performance of electrical impedance tomography systems

The test concept as well as the design of a simple resistor phantom suitable for the evaluation of the properties of electrical impedance tomographic (EIT) systems is presented. Input and transfer impedance of the phantom are matched with those of the human thorax. Amplitude of the local impedance variations similar to in vivo conditions (ventilation) can be intentionally set to perform measurements on different states. The theoretical potential differences between the electrodes are calculated. The evaluation procedure is performed in terms of the local amplitude of the relative impedance change as well as the local distribution of noise. The whole procedure can be applied either to compare quantitatively the performance of different EIT data acquisition systems or to determine the amount of measurement disturbance caused by the external electrical environment in clinical settings.     

Akt1/protein kinase Balpha is critical for ischemic and VEGF-mediated angiogenesis

Akt, or protein kinase B, is a multifunctional serine-threonine protein kinase implicated in a diverse range of cellular functions including cell metabolism, survival, migration, and gene expression. However, the in vivo roles and effectors of individual Akt isoforms in signaling are not explicitly clear. Here we show that the genetic loss of Akt1, but not Akt2, in mice results in defective ischemia and VEGF-induced angiogenesis as well as severe peripheral vascular disease. Akt1 knockout (Akt1-/-) mice also have reduced endothelial progenitor cell (EPC) mobilization in response to ischemia, and reintroduction of WT EPCs, but not EPCs isolated from Akt1-/- mice, into WT mice improves limb blood flow after ischemia. Mechanistically, the loss of Akt1 reduces the basal phosphorylation of several Akt substrates, the migration of fibroblasts and ECs, and NO release. Reconstitution of Akt1-/- ECs with Akt1 rescues the defects in substrate phosphorylation, cell migration, and NO release. Thus, the Akt1 isoform exerts an essential role in blood flow control, cellular migration, and NO synthesis during postnatal angiogenesis.