Acetabular fracture after cycling related falls: High index of suspicion is required to avoid missing the injury on plain radiographs.

Cycling participation as a medium of transport and as a competitive sport has steadily increased in recent decades. Traumatic injuries secondary to falls and collisions occur relatively frequently. Fractures of the hip and pelvis are uncommon with no studies to date reporting their exact incidence in this sport. Injuries specific to the acetabulum are reported even less frequently. We present four cases that highlight the insidious nature of acetabular fractures in cyclists and document their management and recovery. The number of acetabular fractures following falls from bicycles directly onto the lateral hip result in a relatively high number of fractures. Many of these may be missed due to the absence of findings on plain x-ray imaging.It is therefore important to have a high index of suspicion for hip and pelvis fractures when treating cycling related traumatic injuries.

Beam shaping and probe characterization in the scanning electron microscope.

Here we demonstrate the use of nanofabricated grating holograms to diffract and shape electrons in a scanning electron microscope. The diffraction grating is placed in an aperture in the column. The entire diffraction pattern can be passed through the objective lens and projected onto the specimen, or an intermediate aperture can be used to select particular diffracted beams. We discuss several techniques for characterizing the diffraction pattern. The grating designs can incorporate features that can influence the phase and intensity of the diffracted SEM probe. We demonstrate this by producing electron vortex beams.

Limits of Babinet's principle for solid and hollow plasmonic antennas.

We present an experimental and theoretical study of Babinet's principle of complementarity in plasmonics. We have used spatially-resolved electron energy loss spectroscopy and cathodoluminescence to investigate electromagnetic response of elementary plasmonic antenna: gold discs and complementary disc-shaped apertures in a gold layer. We have also calculated their response to the plane wave illumination. While the qualitative validity of Babinet's principle has been confirmed, quantitative differences have been found related to the energy and quality factor of the resonances and the magnitude of related near fields. In particular, apertures were found to exhibit stronger interaction with the electron beam than solid antennas, which makes them a remarkable alternative of the usual plasmonic-antennas design. We also examine the possibility of magnetic near field imaging based on the Babinet's principle.

Comparison of the cellular composition of two different chondrocyte-seeded biomaterials and the results of their transplantation in humans.

Our study compares the histological and immunohistochemical cellular composition of two different chondrocyte-seeded biomaterials and the results of their transplantation. Our study cohort included 21 patients, comprising 19 men and two women with a mean age of 32 years, who were affected by single chondral lesions of the femoral condyles. These patients were enrolled in our study and treated with arthroscopic implantation of the tissue Hyalograft C and/or Brno culture. Brno culture bioengineered with a fibrin-based scaffold contains round cells showing features of differentiated chondrocytes expressing S-100 protein and α-smooth muscle actin. In contrast, in the case of Hyalograft C, the scaffold was made up of a fibrillar network composed of biomaterial fibres of the esters of hyaluronic acid and cells resembling fibroblasts and myofibroblasts and expressing only α-smooth muscle actin. The average size of the defects was 2.5 cm2. Patients were evaluated using the standardized guidelines of the International Knee Documentation Committee. During the comparison of bioptic samples obtained from both patient cohorts, we did not observe any important differences in the histological makeup of the newly formed cartilage. The histological analysis of these two groups of homogeneous patients shows that this bioengineered approach, under proper indications, may offer favourable and stable clinical results over time, in spite of the different matrix and cellular composition of the two transplants used.

Structure, function, and pharmacology of NMDA receptor channels.

NMDA receptors have received much attention over the last few decades, due to their role in many types of neural plasticity on the one hand, and their involvement in excitotoxicity on the other hand. There is great interest in developing clinically relevant NMDA receptor antagonists that would block excitotoxic NMDA receptor activation, without interfering with NMDA receptor function needed for normal synaptic transmission and plasticity. This review summarizes current understanding of the structure of NMDA receptors and the mechanisms of NMDA receptor activation and modulation, with special attention given to data describing the properties of various types of NMDA receptor inhibition. Our recent analyses point to certain neurosteroids as NMDA receptor inhibitors with desirable properties. Specifically, these compounds show use-dependent but voltage-independent block, that is predicted to preferentially target excessive tonic NMDA receptor activation. Importantly, neurosteroids are also characterized by use-independent unblock, compatible with minimal disruption of normal synaptic transmission. Thus, neurosteroids are a promising class of NMDA receptor modulators that may lead to the development of neuroprotective drugs with optimal therapeutic profiles.

Pregnenolone sulfate activates NMDA receptor channels.

Pregnenolone sulfate (PS), an endogenously occurring neurosteroid, has been shown to modulate the activity of several neurotransmitter-gated channels, including the NMDA receptor (NMDAR). NMDARs are glutamate-gated ion channels involved in excitatory synaptic transmission, synaptic plasticity, and excitotoxicity. In this study, we analyzed the effects of PS on calcium signaling in cultured hippocampal neurons and HEK293 cells expressing NMDAR. The cells were loaded with the Ca(2+) sensor Fura-2. In agreement with previous electrophysiological experiments, PS potentiated the increases in intracellular Ca(2+) induced by an exogenous application of glutamate; however, PS also increased intracellular Ca(2+) in the absence of exogenous NMDA agonist. The agonist-independent effect of PS was induced in all neurons studied and in HEK293 cells expressing GluN1/GluN2A-B receptors in a neurosteroid-specific manner. We conclude that PS is an endogenous NMDA agonist that activates the GluN1/GluN2A-B receptors.

Direct oxymetric peripheral tissue perfusion monitoring during open heart surgery with the use of cardiopulmonary bypass: preliminary experience.

BACKGROUND: Regional hypoperfusion has been associated with the development of postoperative organ dysfunction in cardiac surgery involving cardiopulmonary bypass (CPB). Direct tissue oxymetry is a potentially new method for monitoring the quality of the peripheral tissue perfusion during CPB. The aim of this study was to assess the effects of CPB in skeletal muscle oxygenation when measured in the deltoid muscle by direct oxymetry during perioperative period. METHOD: Seven patients underwent on-pump coronary artery bypass grafting. Direct oxymetry was performed by an optical cathether introduced into the deltoid muscle. Continuous measurement was made during the surgical procedure and the postoperative period. Mean arterial blood pressure, blood flow during CPB, laboratory markers of tissue hypoperfusion, blood gases and body temperature were also recorded. RESULTS: Interstitial muscle tissue oxygen tension (pO(2)) decreased after the introduction to anaesthesia and, more significantly, during CPB. After the disconnection from CPB at the end of the operation, the pO(2) returned to pre-anaesthetic values. During the first hours after admission of the patients to the intensive care unit, the pO(2) progressively decreased, reached a minimum value after four hours, and increased slowly thereafter. There was a significant correlation of pO(2) with mean arterial blood pressure and blood flow during that time. CONCLUSION: The result of this first measurement seems to demonstrate that the standard technique of conducting cardiopulmonary bypass produces low muscle oxygen tension and, thus, little perfusion of skeletal muscle. The data also indicate that both high mean arterial blood pressure and high flow are necessary during CPB to ensure skeletal muscle perfusion. The investigation is continuing.

Pregnenolone sulfate modulation of N-methyl-D-aspartate receptors is phosphorylation dependent.

Pregnenolone sulfate (PS), an endogenously occurring neurosteroid, has been shown to modulate the activity of several neurotransmitter-gated channels, including the N-methyl-D-aspartate receptor (NMDAR). NMDARs are glutamate-gated ion channels involved in excitatory synaptic transmission, synaptic plasticity, and excitotoxicity. To determine the mechanism that controls PS sensitivity of NMDARs, we measured NMDAR responses induced by exogenous agonist application in voltage-clamped HEK293 cells expressing NR1/NR2B NMDARs and cultured rat hippocampal neurons. We report that PS potentiates the amplitude of whole-cell recorded NMDAR responses in cultured hippocampal neurons and HEK293 cells; however, the potentiating effect of PS on NMDAR in outside-out patches isolated from cultured hippocampal neurons and HEK293 cells was lost within 2 min after patch isolation in a neurosteroid-specific manner. The rate of diminution of the PS potentiating effect was slowed by protein phosphatase inhibitors. Treatment of cultured hippocampal neurons with a nonspecific protein kinase inhibitor and a specific protein kinase A (PKA) inhibitor diminished PS-induced potentiation, which was recovered by adding a PKA, but not a protein kinase C (PKC), activator. These results suggest that the effect of PS on NMDARs is controlled by cellular mechanisms that are mediated by dephosphorylation/phosphorylation pathways.

[Mediolateral episiotomy and anal sphincter trauma]. / Mediolaterální epiziotomie a poranení análního sfinkteru.

OBJECTIVE: A summary of recent knowledge of the correlation between mediolateral episiotomy and anal sphincter injury. DESIGN: Review. SETTING: Department of Gynaecology and Obstetrics, Charles University and University Hospital Pilsen. CONCLUSIONS: The methodology of most studies is not well managed. Four problematical points were identified: definition of the mediolateral episiotomy, practical execution of the mediolateral episiotomy, diagnostics of perineal trauma and classification of the perineal trauma. Mediolateral episiotomy is often deficiently defined. Definitions differ depending on individual textbooks or departments. The majority of studies gives no definition and no description of the practical execution of an episiotomy or describes it inadequately. To the current knowledge there is no international consensual definition, which is used universally. Until 2003, there was no study evaluating adequate implementation of the mediolateral episiotomy. It appears that most of executed mediolateral episiotomies are not truly mediolateral. The angle of inclination between 40-60 degrees was suggested. According to the latest study, the lower limit of the mediolateral episiotomy definition (40 degrees) appears to be insufficient. At the present time, the correlation between mediolateral episiotomy and perineal trauma cannot be precisely evaluated. Before analyzing the benefits and risks of mediolateral episiotomy, an international consensus must be found, that would establish an exact definition of mediolateral episiotomy.

[S-100 protein positivity in osteogenic tumours and tumour-like bone forming lesions]. / Exprese S-100 proteinu v osteogenních nádorech a tumoriformních osteoplastických lézích.

Various osteogenic tumours and bone producing tumour-like lesions of bone were examined for S-100 protein using the immunostaining methods. The positive reaction for S-100 protein of some bone cells was detected not only in osteoblastic osteosarcomas and osteoblastomas, but also in osteoplastic reactive lesions, fibrous dysplasia, Paget's disease and in the tissue of the bony callus. The positive reaction for osteocalcin in these cells showed, that they may be of osteoblastic and osteocytic lineage. The S-100 protein positive bone cells have to be differentiated from chondrocytes persisting in new-formed bone trabecullae. On the one hand S-100 protein positive osteocytes and osteoblasts may represent transient form of osteocytes histogenetically related to chondrocytes, but we were not able to prove such suggestion. Therefore, S-100 protein positivity can be caused by polyclonal character of the used antibody, that is a mixture of three antibodies, S-100 A1, A6 and anti B2. The specificity of these three components differs depending on the histogenesis of cells and their functional status. Such explanation is supported by the results of our study, because we also observed intense positivity of bone cells in the reaction with monoclonal antibody against S-100A6. In contrast, no staining of bone cells was detected with monoclonal antibodies against S-100 A1 and B2.

Temperature dependence of NR1/NR2B NMDA receptor channels.

N-methyl-D-aspartate (NMDA) receptors are highly expressed in the CNS, mediate the slow component of excitatory transmission and play key roles in synaptic plasticity and excitotoxicity. These ligand-gated ion channels are heteromultimers composed of NR1 and NR2 subunits activated by glycine and glutamate. In this study, patch-clamp recordings were used to study the temperature sensitivity of recombinant NR1/NR2B receptors expressed in human embryonic kidney (HEK) 293 cells. Rate constants were assessed by fitting a six-state kinetic scheme to time courses of transient macroscopic currents induced by glutamate at 21.9-46.5 degrees C. Arrhenius transformation of the rate constants characterizing NMDA receptor channel activity indicates that the most sensitive were the rate constants of desensitization (temperature coefficient Q(10)=10.3), resensitization (Q(10)=4.6) and unbinding (Q(10)=3.6). Other rate constants and the amplitude of single-channel currents were less temperature sensitive. Deactivation of responses mediated by NR1/NR2B receptors after a brief application of glutamate was best fit by a double exponential function (tau(fast): Q(10)=3.7; tau(slow): Q(10)=2.7). From these data, we conclude that desensitization/resensitization of the NMDA receptor and glutamate unbinding are especially temperature sensitive and imply that at physiological temperatures the channel kinetics play an important role in determining amplitude and time course of NMDA receptor-mediated postsynaptic currents and these receptors mediated synaptic plasticity.

[Occult anal sphincter tear--up-to-date knowledge]. / Okultní ruptura análního sfinkteru behem porodu--soucasné znalosti.

OBJECTIVE: Summary of the current knowledge of sonographically and clinically detectable anal sphincter injury. DESIGN: Review. SETTING: Department of Gynaecology and Obstetrics, Charles University and University Hospital Pilsen. SUMMARY: Review of the current international literature covering the given problem. Occult anal sphincter tear is defined as an injury, which is clinically undetectable and recognizable just on endoanal ultrasonography. Total frequence of anal sphincter defects detected by sonography varies between 19-67%. At any rate majority of them likely seem to be injuries which are clinically detectable, however undiagnosed and missed. Isolated defect of internal anal sphincter is an example of real occult anal sphincter injury. This is found in around 2% of all vaginal deliveries. A diligent digital examination of perineum after the delivery and a proper education of perineal anatomy is the cornerstone in improving of the diagnostics. Endoanal ultrasound may serve as a tool in facilitation of the diagnosis.

Morphology and physiology of lamina I neurons of the caudal part of the trigeminal nucleus.

It has been suggested that in mammals, trigeminal lamina I neurons play a role in the processing and transmission of sensory information from the orofacial region. We investigated the physiological and morphological properties of trigeminal subnucleus caudalis (Sp5C) lamina I neurons in slices prepared from the medulla oblongata of 13- to 15-day-old postnatal rats using patch-clamp recordings and subsequent biocytin-streptavidin-Alexa labeling. Twenty-five neurons were recorded and immunohistochemically stained. The Sp5C lamina I consisted of several types of neurons which, on the basis of their responses to somatic current injection, can be classified into four groups: tonic neurons, which fired throughout the depolarizing pulse; phasic neurons, which expressed an initial burst of action potentials; delayed onset neurons, which showed a significant delay of the first action potential; and single spike neurons, characterized by only one to five action potentials at the very beginning of the depolarizing pulse even at high levels of stimulation intensity. Electrical stimulation of the spinal trigeminal tract evoked AMPA receptor-mediated excitatory postsynaptic currents (EPSC) exhibiting a strong polysynaptic component. AMPA receptor-mediated miniature excitatory postsynaptic currents (mEPSC) were characterized by a 10-90% rise time of 0.50+/-0.06 ms and a decay time constant of 2.5+/-0.5 ms. The kinetic properties of NMDA receptor-mediated EPSCs were measured at +40 mV. The 10-90% rise time was 8+/-2 ms and the deactivation time constants were 94+/-31 and 339+/-72 ms, respectively. Intracellular staining and morphological analysis revealed three groups of neurons: fusiform, pyramidal, and multipolar. Statistical analysis indicated that the electrophysiological properties and morphological characteristics are correlated. Tonic and phasic neurons were fusiform or pyramidal and delayed onset and single spike neurons were multipolar. Our results show that both the physiological and morphological properties of Sp5C lamina I neurons exhibit significant differences, indicating their specific integration in the processing and transmission of sensory information from the orofacial region.

Trephinations--old surgical intervention.

Trephination of the skull is an old surgical procedure practised in both the Old and New Worlds from the Neolithic period 7,000 years ago up to the present. Four methods (scratching, cutting, drilling and circling) were used for therapeutic or ritual (magical) reasons, predominantly in older males. The survival rate was between approximately 25% and 75%, the drilling and especially cutting being most dangerous. Macroscopic, CT and histopathological examination of three trephined skulls from the collection of Hrdlicka's Museum of Man, Charles University, revealed two types of bone defect. In the first type the margin of the defects was covered by the cortical bone of identical structure as the cortical bone on the inner and outer surface of the surrounding skull bones. These cases probably represent defects that healed in living persons for a long time, and consequently new cortical bone developed (skull No. 1). However, congenital origin of defects of this type cannot be excluded. The second type of defects, without cortical bone cover at the hole margin, could be caused by trauma in the post mortem period or may have been performed during the people's lifetimes--if they died shortly after their skull damage, so the healing period was too short for the formation of new cortical bone (skull No. 2 and 3).

Subtype-dependence of N-methyl-D-aspartate receptor modulation by pregnenolone sulfate.

N-methyl-D-aspartate receptors play a critical role in synaptogenesis, synaptic plasticity, and excitotoxicity. They are heteromeric complexes of NR1 combined with NR2A-D and/or NR3A-B subunits. The subunit composition determines the biophysical and pharmacological properties of the N-methyl-D-aspartate receptor channel complex. In this study, we report that responses mediated by recombinant rat N-methyl-D-aspartate receptors expressed in human embryonic kidney HEK293 cells are differentially affected by naturally occurring neurosteroid pregnenolone sulfate. We show that responses induced by 1mM glutamate in NR1-1a/NR2A and NR1-1a/NR2B receptors are potentiated five- to eight-fold more by pregnenolone sulfate than responses of NR1-1a/NR2C and NR1-1a/NR2D receptors with no differences in the concentration of pregnenolone sulfate that produced 50% potentiation. In addition to potentiation, pregnenolone sulfate also has an inhibitory effect at recombinant N-methyl-D-aspartate receptors, with values of the concentration of pregnenolone sulfate that produces 50% inhibition of NR1/NR2D=NR1/NR2C

Physiology and pathology of NMDA receptors.

Ionotropic glutamate receptors of the N-methyl-D-aspartate (NMDA) subtype are highly expressed in the central nervous system and are involved in excitatory synaptic transmission and synaptic plasticity. Prolonged activation of NMDA receptors can lead to excitotoxicity, which is implicated in the pathogenesis of neurodegeneration occurring in various acute and chronic disorders of the central nervous system. Recent advances in understanding the function, pharmacology, genetics and structure of NMDA receptors has promoted a search for new compounds that could be therapeutically used. These compounds act on agonist binding sites, either apart from them or directly within the ion channel pore. Members of the last group are called open channel blockers, and some of them, such as memantine and ketamine, are already clinically used. Kinetic modeling of NMDA receptor activity was employed to define the effects of various groups of modulators. Quantifying the action of these substances by kinetic parameters can help us to reveal the molecular mechanism of action at the receptor and to characterize the dependence of its action on the mode of NMDA receptor activation. Two modes are considered: phasic activation, induced by synaptically released glutamate, and tonic activation, which is expected to occur under pathological conditions when low, but sustained levels of glutamate activate NMDA receptors. The aim of our review is to summarize the recent data about the structural and functional properties of NMDA receptors and their role in long-term potentiation and excitotoxicity.

Desmin-positive and alpha-smooth muscle actin positive chondrocytes in human defective articular cartilage--preliminary report.

We studied the results of immunostaining for S-100 protein, alpha-smooth muscle actin, muscle specific actin and desmin in articular cartilage specimens obtained during an arthroscopy from eight patients with different degrees of osteoarthritis of the knee joint. In all cases, most of the cartilage cells were strongly positive for S-100 protein. Actin positive chondrocytes were present in four samples showing repair cartilage changes with occurrence of fibrocartilage tissue. Moreover, in one case, we observed typical desmin-positive chondrocytes in the layer of cartilage filling the defect of the articular cartilage surface. The expression of desmin can be regarded as a reaction to trauma or the indication of an inherent abnormality. The chondrocytes probably switched on smooth muscle features during the healing process, because desmin is to a great extent a typical muscle cell marker. This fact could probably support our previous supposition that cartilage cells expressing muscle markers could be designated as myochondroblasts and myochondrocytes analogously to the terminology of myofibroblasts. It is possible that during the healing of the cartilage defects, such a transformation of the immunophenotype of the cartilage cells is quite frequent, but it could also be only transient nature only.

[Endoscopic investigations in children under 3 years of age at the clinic of paediatric surgery]. / Endoskopické výkony u detí do 3 let na Klinice detské chirurgie.

BACKGROUND: Retrospective study of gastroscopic investigations in children under 3 years of age. METHODS AND RESULTS: Since 1.1.2002 till 31.10.2004 we performed 119 endoscopic investigations in children of this age. 21 patients were excluded because of missed documentation. The average weight of our children was 11.8 kg. (min. 2.8, max 20 kg). In 55 cases suspicion for the oesophageal or gastric corrosion was the reason of investigations. in 24 cases swallowed alien bodies, in 10 patients we performed dilatation of oesophageal stenosis in repeated sessions in 1-6 moths periods. In 4 children we introduced percutaneous endoscopic gastrostomy (PEG), in 3 children ERCP was performed because of cystic dilatation of the bile duct. In I child the supposed hematemesis was the reason of gastroscopy (negative) and in one patient oesophageal varicula were assumed (negative). CONCLUSIONS: Oesophageal or gastric corrosions were assured in 12 cases (Grade 1.-2.:20.2%). 5 alien bodies couldn't be removed because of peristalsis, 1 object because of its dimensions (25% failures). Our dilations were performed in oesophageal stenosis with bougies or balloon dilator. 9 children were first operated for oesophageal atresia (Vogt IIIb), 1 child was after an operation for oesophageal corrosion with perforation.

[Classic adamantinoma, differentiated adamantinoma and osteofibrous dysplasia of long bones]. / Klasický adamantinom, diferencovaný adamantinom a osteofibrózní dysplazie dlouhých kostí.

BACKGROUND: Just for over 100 years, adamantinoma has been recognized as a primary enigmatic bone tumour with epithelial characteristics and predominantly involving the tibia. Several similarities between osteofibrous dysplasia has been recognised, differentiated adamantinoma and classic adamantinoma. The purpose of this study was to compare these lesions and to define their histogenesis and mutual relations. METHODS AND RESULTS: Comparison of the clinical, radiologic, histological, immunohistochemical and electron microscopic findings was carried out on 6 cases of classic adamantinoma, 2 cases of differentiated adamantinoma and 2 cases of osteofibrous dysplasia. This study confirmed the epithelial nature of long bone classical and differentiated adamantinomas irrespective of their wide-ranging morphologic pattern that can mimic tumours of various origins. Both types of adamantinoma were positive for cytokeratins in coexpression with vimentin. The epithelial component of the differentiated adamantinoma was much smaller than in classic adamantinoma and was present in scattered islands or single cells distributed within fibrovascular stoma. In one case the scattered epithelial cells had abundant eosinophilic cytoplasm and they resembled rhabdoid elements. On the basis of distinct histological pattern, a new variant of differentiated adamantinoma was described--a rhabdoid variant. In our cases of osteofibrous dysplasia occurring in two children with deformity of the tibia no epithelial cells were identified by the immunohistochemical methods. The lesions were composed of variably shaped spicules of woven and lamellar bone separated by a fibrovascular stroma. The woven bone spicules were surrounded by a uniform rim of plump osteoblasts. The lesion exhibited a zonal phenomenon with maturation of woven bone to bone with a lamellar configuration at the periphery of the lesion. The similar zonal phenomenon was also observed in the cases of differentiated adamantinoma. CONCLUSIONS: On the basis of the clinical, histological, immunohistochemical and electron-microscopical studies, a common histogenesis for classic adamantinoma, differentiated adamantinoma and osteofibrous dysplasia seems likely. The epithelial cell components of these lesions exhibit similar cytokeratin immunoprofiles and ultrastructural features. However, the prognosis for classic adamantinoma is much less favorable than that for cases of osteofibrous dysplasia and differentiated adamantinoma.