Investigation of an apodized imaged Hartmann wavefront sensor.

Quantitative wavefront measurements are demonstrated using a Hartmann mask re-imaged onto a camera. The wavefront is reconstructed using standard algorithms applied to the difference of beamlet centroids determined from fluence distributions obtained for two different longitudinal locations of the mask. The wavefront of the optical wave in the object plane is measured independently of imaging-system collimation. Apodization obtained with spatially dithered distributions of small transparent or opaque pixels improves the measurement accuracy by reducing the spatial-frequency content of the mask holes. Simulations and experiments demonstrate the excellent accuracy of this diagnostic over a wide range of parameters, making it suitable, for example, to characterize laser systems.

Maximum Proton Energy above 85 MeV from the Relativistic Interaction of Laser Pulses with Micrometer Thick CH_{2} Targets.

We present a study of laser-driven ion acceleration with micrometer and submicrometer thick plastic targets. Using laser pulses with high temporal contrast and an intensity of the order of 10^{20} W/cm^{2} we observe proton beams with cutoff energies in excess of 85 MeV and particle numbers of 10^{9} in an energy bin of 1 MeV around this maximum. We show that applying the target normal sheath acceleration mechanism with submicrometer thick targets is a very robust way to achieve such high ion energies and particle fluxes. Our results are backed with 2D particle in cell simulations furthermore predicting cutoff energies above 200 MeV for acceleration based on relativistic transparency. This predicted regime can be probed after a few technically feasible adjustments of the laser and target parameters.

[The surgical repair of thoracic deformities in adult patients]. / Chirurgische Behandlung von Brustkorbdeformitäten bei erwachsenen Patienten.

The authors' experience with the surgical repair of thoracic deformities in 45 adult patients is reported. The most frequent deformity was pectus excavatum (n = 42), the asymmetric form of which was observed in 59 % of our patients. The patients were treated by means of a modified Ravitch method, with the retrosternal introduction of a Jensen strut. The strut was left in place for one year and then was removed via a small incision. With the exception of two cases of postoperative pneumothorax, no other postoperative complications were seen and no patient died. In the follow-up 1 year after removal of the Jensen strut, no recurrent deformities were observed in 36 patients. On the basis of these results, we consider the described technique as the method of choice in the treatment of congenital thoracic deformities in adult patients.

The value of 18-FDG PET/CT imaging in a patient with atypical metastatic colorectal cancer--case report: 18-FDG PET/CT in colorectal cancer.

BACKGROUNDS: Cancer metastasis to skeletal muscle is very rare. Lung cancer, renal cell carcinoma and malignant melanoma have been reported as the most frequent primary tumours. Diagnosis of muscle metastasis from other primary cancer sites is more than problematic. CASE: In this paper we report a case of metastasis of colorectal cancer in a 44-year-old man who underwent left-sided hemicolectomy due to the tumour mass in his left colic flexure followed by liver metastasectomy and cryocautery of the non-resectable metastasis in the VII segment. Subsequently, the patient was treated with two lines of chemotherapy. However, shortly after initiation of the second chemotherapy line he started to suffer from unbearable pain in the lumbosacral region. Neither a whole spinal cord MRI nor abdominal CT scan and scintigraphy explained the origin of the pain. Finally, PET/CT examination clarified the origin of the pain and showed massive hypermetabolic metastatic lesions in the muscles, further confirmed by autopsy. CONCLUSION: Thus, among the different imaging techniques, FDG PET/CT enables the detection of metabolically highly active tumour cells, undetectable by other conventional imaging means.

Experimental discrimination of ion stopping models near the Bragg peak in highly ionized matter.

The energy deposition of ions in dense plasmas is a key process in inertial confinement fusion that determines the α-particle heating expected to trigger a burn wave in the hydrogen pellet and resulting in high thermonuclear gain. However, measurements of ion stopping in plasmas are scarce and mostly restricted to high ion velocities where theory agrees with the data. Here, we report experimental data at low projectile velocities near the Bragg peak, where the stopping force reaches its maximum. This parameter range features the largest theoretical uncertainties and conclusive data are missing until today. The precision of our measurements, combined with a reliable knowledge of the plasma parameters, allows to disprove several standard models for the stopping power for beam velocities typically encountered in inertial fusion. On the other hand, our data support theories that include a detailed treatment of strong ion-electron collisions.

Osteon orientation of the diaphysis of the long bones in man.

The orientation of osteons has been described in the long bones of man, using a special macroscopic method, which enabled the study of the osteonal architecture throughout the extent of the diaphysis. The osteons in all bones are arranged in two helical systems of opposite directions, which lie on the opposite sides of the diaphysis. The inclination of osteon direction from the bone axis in remarkably constant, varying between 5 degrees and 15 degrees. The boundary between the two fields is sharp. This special type of osteon orientation corresponds with the directions of the maximum principal stress and/or strain in the walls of the bones, which are exposed to both the bending and torque moments. The typical orientation of osteons reflects the history of loading of the bones in the course of physiological activity. The dominant stress state of every bone could be deduced from the osteon orientation and from the position of the pressure and tension fields on the surface of the bone.

Spatial organization of the haversian bone in man.

The osteons in all human long bones are grouped in two helical antirotary systems of opposite oblique directions, situated in the contralateral walls of the diaphysis. Several arguments support the hypothesis that this special architecture arises from functional adaptations and that it depends on the orientation of the first principal stress. A new macroscopic method based on the filling of vascular canals of the undecalcified, polished bone with India-ink enabled us to study the spatial architecture of the haversian bone in the entire diaphysis. The osteon directions in normal and atypical femurs was compared with the direction of the first principal stresses, determined analytically in a cylindrical tube model of the diaphysis subjected to a combination of bending, torsion and compression. Under combined loading with the bending moment in the frontal plane to the medial side and with the torque moment in the sense of external rotation, the direction of the first principal stresses corresponded with the direction of osteons in the diaphysis of the femur. In both cases, the first principal stresses, as well as the osteons, were oriented in the opposite oblique direction in the medial and lateral walls of the model and of the bones. Between the two oblique fields a sharp boundary with an atypical organization of the principal stresses and osteons existed. In atypical femurs the osteonal orientation was longitudinal (likely unloaded femurs) or rotated 90 degrees (markedly anteriorly convex femurs). These observations support the hypothesis of a causal relation between the loading mode and the dominant osteonal direction. The organization of the haversian bone seems a typical example of functional adaptation.

Tracheal stenosis complicated with tracheoesophageal fistula.

OBJECTIVE: The aim of the present study was to evaluate the results of surgical treatment in patients with simultaneous occurrence of postintubation tracheal stenosis (TS) and tracheoesophageal fistula (TEF). METHODS: In the group of 51 patients with postcannulation tracheal stenosis who underwent segmental resection, TEF was identified simultaneously in five (10%) of them. The mean age of the TS-TEF patients was 43 years (range 35-60 years). The patients underwent a single-stage operation during which TEF was sealed and resection of the stenotic tracheal segment was performed. RESULTS: The cause of TEF and of TS was artificial pulmonary ventilation by tracheostomy tube (n=4) or by endotracheal tube (n=1) with a simultaneous insertion of nasogastric tube. In one of the patients with tracheostomy the fistula resulted from an injury to the pars membranacea tracheae and the esophageal wall during tracheostomy. All the patients were respiring spontaneously before the surgical treatment. The mean length of the fistula was 24.0 mm (range 15-30 mm), the fistulae were located at the junction of the upper and middle third of the trachea. The mean length of the resected tracheal segment was 29.6 mm (range 26-32 mm). Postoperative complications were not observed in the group of the TS-TEF patients, none of them died. CONCLUSIONS: The method of choice of the surgical treatment of TEF associated with TS is a single-stage procedure in the patient who respires spontaneously.

Aminopeptidases and angiotensin I-converting enzyme activities in primary human lung tumors and lung parenchyma.

The activities of alanyl aminopeptidase (AAP), arginyl aminopeptidase (RAP), alpha-glutamyl aminopeptidase (EAP) and angiotensin I-converting enzyme (ACE) were investigated in primary human lung tumors of different histological types and in matched lung parenchyma. In contrast to the studied aminopeptidases whose activity differences between tumor and lung tissues were infrequently significant, the activity of ACE was decreased highly significantly in the majority of lung tumors.

Bronchial carcinoid tumors: long-term outcome after surgery.

The objective of the present study was to evaluate clinical condition and results of surgical treatment of patients with typical and atypical bronchial carcinoids. The study was based on retrospective analysis of a total of 96 patients (mean age 47.3 year, age range 21-76, 44 men and women 52), who were surgically treated for bronchial carcinoid between 1985-2001. We assessed symptomatology of the disease, type of surgical intervention, tumor histology and staging, and postoperative 5-year and 10 year survival rates. The main sign of disease was respiratory inflammation. The carcinoid syndrome was not found in any patient. Most patients (n=68) were operated for central form of the tumor. The micromorphological tumor diagnosis was established prior to surgery in 76.5% patients with the central form of carcinoid. Surgical treatment included lobectomy (n=49), bronchoplastic procedure (n=14), sleeve lobectomy (n=9), atypical resection and segmentectomy (n=11), pneumonectomy (n=7) and tumor enucleation (n=5). Histological analysis revealed typical carcinoid in 77 cases (80.2%) and atypical carcinoid in 19 (19.8%). Lymph nodes (N1 and/or N2) were examined by histology in 84 patients and lymph node metastases were found in 13 (19.4%) of 67 patients with typical carcinoid and in 5 cases (29.4%) of 17 with atypical carcinoid. In the postoperative period on patient died from embolism to the arteria pulmonalis. Postoperative complications (atelectasis, prolonged air leak, bronchopleural fistula) were observed in 11.4% of patients. Tumor relapse occurred only in two patients with typical carcinoid. Postoperative 5-year and 10-year rates amounted to 98.6% and 87.3%, respectively, in typical carcinoid 94.5% and 73.5% in atypical carcinoid. The survival rates of patients with typical and atypical bronchial carcinoids were not significantly different (p>0.05). The surgical management is the treatment of choice in bronchial carcinoids. Results of this study indicate that the 5-year survival in patients with either histological type of bronchial carcinoid is excellent and the prognosis of operated patients is very good even in the case of regional lymph nodes infiltration by the tumors.

Are there any differences in the excitation-contraction coupling of the working myocardium of adult and newborn guinea-pigs?

Action potentials (APs) and the force of isometric contractions of the right ventricular papillary muscles were measured in adult and newborn guinea-pigs. The measurements were carried out in the steady state with the rate of stimulation of 0.1, 1, and 2 Hz, and further some measurements were done in which Sr2+ was substituted for Ca2. The duration of APs of the newborn animals without pharmacological treatment was significantly shorter in comparison with that of the adults at all the used stimulation frequencies. An analogous sensitivity was found in the contractile force to increased stimulation frequency and when the steady state stimulation was discontinued by the insertion of interpolated extrasystoles in papillary muscles of adult or newborn animals. The biphasic contractions of papillary muscles were evoked in both groups of animals by the incomplete substitution of Sr2+ by Ca2+ in the presence of isoprenaline. The early component of the biphasic contractions had a faster course as compared to the late component and disappeared in the presence of caffeine in both groups of animals. Our results suggest that the heart cells of newborn guinea-pigs probably possess the sarcoplasmic reticulum (SR), whose function does not differ in quality from that of the adult guinea-pigs. The postnatal prolongation of APs is therefore not probably the result of postnatal development changes of the functions of SR, but could be related to changes in the relations between the surface and volume of the heart cell during its growth.

Developmental defects and chromosomal aberrations in spontaneous abortions and stillbirths.

The authors analysed 1488 cases of spontaneous abortions and stillbirths in Bratislava. They focused on the course of human embryogenesis and the chromosomal constitution. A high mean frequency rate of both developmental defects (14.4%) and chromosomal aberrations (33.6%) was revealed and both were found to be in close relation with the length of gestation. The most severe developmental defects occurred mostly in early stages of human embryogenesis, i.e. in the 1st trimester of gestation.

Erdheim-Chester disease. A case report.

A 63-year old man had a history of diabetes insipidus, arthralgias and myalgias, weight loss, relapsing fever and malaise. Increased uptake of Tc-99m was found predominantly in distal antebrachia, in distal femurs and in both trochanters and tibias on the bone scintigraphy. The chest radiograph showed reticulonodular pattern and the high resolution computed tomography (HRCT) scans revealed diffuse infiltrative lung disease with small multiple nodules and widening of interlobular septs. Videothoracoscopic lung biopsy and biopsy of tibial lesion were perfomed. The histopathologic examination proved non-Langerhans cell histiocytosis-Erdheim-Chester disease. Treatment with prednisone reduced the pain and fever and improved the vital capacity of the lungs while the changes in the lungs and bones remained unchanged.

[Mechanical loading of the human femoral neck]. / Mechanické namáhání krcku femuru cloveka.

PURPOSE OF THE STUDY: The aim of the study is to explain what is the actual loading of human proximal femur. MATERIAL: Measuring of stress is based on 5 femurs of normal shape (bones obtained from dissection and ossuary). In order to determine the direction of the resultant force the authors used 30 ossuary bones of different age but of analogical shape. METHODS: By means of their own graphic method the authors identified the direction of appositional growth of femoral neck which contains with the longitudinal diaphyseal axis the angle of 26 degrees (alpha angle). The value of the angle is identical with the direction of the resultant force acting on the femoral head in vivo. Tensometric method was used for the measuring of stress on the medial and lateral surfaces of femoral neck during loading in direction of the determined resultant force. Linear strain gauges of Hottinger type were used for the measuring and Instron apparatus was applied for biomechanical analysis in which femoral heads were loaded by a standard force of 50 kg, first in the direction of femoral diaphyseal axis and then gradually (always by 5 degrees) in the divergence from the diaphyseal axis up to 50 degrees. RESULTS: Appositional growth of femoral neck with regard to the longitudinal diaphyseal axis is progressing under the alpha angle (alpha = 26 degrees), which corresponds to the direction of the resultant force. The value of the compression stress on the medial surface of the neck ranged between--165 and -300 microstrain (mean value -239 microstrain). On the lateral surface there is a tension stress ranging between +20 up to +140 microstrain (main value +64 microstrain). The ratio of stress on both sides (surfaces) was 3.8:1. The point of zero stress is located in the lateral part of the neck, i.e. in the area of lateral trajectorial system of cancellous bone. DISCUSSION: The method of measuring of the direction of the resultant force on the basis of the bone development (on the basis of superposition of successive growth stages) is despite certain inaccuracies a correct procedure. The alpha angle (alpha = 26 degrees) identified by the authors corresponds with Pauwels' calculation (24 degrees) and Bergman's findings (22 degrees up to 27 degrees). The identified values of stress show that the opinion on a purely axial loading of the neck is wrong and has to be corrected. Femur is not exposed in the frontal plane to the action of the resultant force only in one direction as supposed e.g. by Pauwels but the direction of the resultant force oscillates within a limited extent from different directions. It means that the lateral wall of femoral neck is exposed to alternating both tensile and compression loading. CONCLUSION: The presented work allows to specify the opinions on the way of loading of human proximal femur. Our experiments have shown that apart from axial pressure the femoral neck is exposed also to bending forces. This way of loading also corresponds with the oval shape and thickened medial wall of the neck.

[Structure of compact bone and types of stress in the long bones in humans]. / Struktura kompaktní kosti a zpusob namáhání dlouhých kostí cloveka.

The authors elaborated a new macroscopic method which made it possible to analyze the orientation of osteons in the entire diaphysis. All long bones of the human extremities were thus analyzed. In each bone the osteons are arranged in a specific pattern but according to a uniform plan. Most of them are oriented in an oblique direction and are arranged as two helices of opposite directions located on opposite sides of the bone. The two fields are separated by a sharp borderline. Biomechanical analysis revealed that the orientation of the osteons is consistent with the direction of the maximal principal stress which depends on the normal and torsional stress to which the bone is exposed. From the orientation of osteons the authors derived ex post the mode of dominant loading of all long bones: the femur is exposed to bending in the medial direction and to outer rotation, the tibia is exposed to bending in dorsal direction and to inner rotation. The humerus is bent in the medial direction, the radius in the dorsal one. Both these bones are exposed to loading in inner rotation. In the ulna and fibula the mode of stress could not be assessed by the authors' method. The results are summarized in two diagrams which indicate the orientation of osteons and the way in which the long bones in man are exposed to load. The authors discuss the theoretical and practical impact of these findings.

["Tension" and "pressure" osteons - reality or myth?]. / "Tahové" a "tlakové" osteony - realita nebo mýtus?

The underlying study tests the hypothesis on the existence of two types of osteons, the "tension" and the "pressure" ones. Osteons of the first type should be built under the influence of tension and should manifest greater strength in tension. The contrary applies to the "pressure" osteons. The ultimate strength of the bone tissue in tension and compression was studied on samples from the medial wall of the femoral diaphysis, subjected in vivo to compression, and on samples from the lateral wall, subjected to tension. All samples were manufactured with the long axis corresponding to the orientation of osteons, arranged in two helical antirotary systems situated in the contralateral walls of the diaphysis. The osteon orientation was ascertained after filling vascular canals with India-ink. The bone samples were tested using the Schenk Trebel RM 10-K machine. Tension tests found no difference in bone strength between samples from the lateral and from the medial walls. In compression tests, three cases manifested greater strength in samples from the medial wall, two cases in samples from the lateral wall. Such results speak against the hypothesis of the existence of two functional types of osteons. A complementary series of experiments showed that the tension strength is greatest in samples having a longitudinal orientation of osteons and that it decreases rapidly with growing inclination of osteons from the axis of loading. The dominant factor, responsible for the bone strength, is therefore the osteon orientation and not the mode of mechanical loading in vivo or the orientation of collagen fibres. Key words: haversian bone, osteons, strength of bone.

[Dependence of mechanical strength on the architecture of the compact bone of human shaft.]. / Závislost mechanické pevnosti na architektonice kompaktní kosti diafýzy u cloveka.

A secondarilly remodelled bone (the haversian bone) forming a wall of human shaft represents a significantly anisotropic material, which has different strengths in different directions. One of the factors influencing mechanical properties (strength in particular) of the bone is the architectonics of the compact bone. Osteons of the haversian bone are arranged in the direction of the dominant first principal stress and create two antirotational spiral systems in the opposite walls of the shaft. The aim of the work was to found out how the bone tensile strength depends on the orientation of osteons and check whether the premise applies that the architectonics of the haversian bone depends on the directions of the first principal stress and in what relation of strength moments the direction of the first principal stress corresponds to the actual orientation of osteons. The results of the tensile strength tests in wet samples from 10 femurs and the strength of the whole shaft in 9 pairs of femurs (cadaver material) have confirmed the premise that osteons are arranged in the directions of the dominant first principal stress and depend on the relation between bending and torsion moments. The strength of the femoral shaft is maximal in the physiological way of loading, i.e. in medial bending and outer rotation. The decisive motion on which the strength of the bone depends is torsion. In non-physiological loading the femoral shaft (by an opposite bending moment or opposite torsion moment in medial bending) the strength of the bone is significantly lower. From the biomechanical viewpoint the architecture of the haversian bone has an optimal and efficient structure. Key words: compact bone, bone strength, types of loading.

[Congenital nephrotic syndrome]. / Kongenitálny nefrotický syndróm.

Only one case of congenital nephrotic syndrome was recorded in a series of 2,500 bioptic examinations of the kidney performed over a period of 20 years. In necroptic material examined over the same period of time congenital nephrotic syndrome was recorded three times. At the first bioptic examination of the kidneys only minimal changes of glomeruli were diagnosed. Rebiopsy exhibited proliferation of mesangial cells, focal segmental glomerular sclerosis, cystically dilated tubules in the juxtamedular region of the cortex, and focal tubulointerstitial reactive changes, which in accordance with the clinical findings were assessed as congenital nephrotic syndrome of the Finnish type. Comparison of the findings observed at the first biopsy and at rebiopsy demonstrates the importance of proper collection of a representative sample for renal biopsy.

Mixed hepatoblastoma in the adult: morphological and immunohistochemical findings.

A case of mixed hepatoblastoma in a 66-year-old man is discussed. Assessment of malignant mesenchymal and malignant epithelial elements yields the diagnosis. In the reported case, the epithelial area consisted of fetal hepatocytes. Distinct ductal differentiation, chondroid and even asteoid metaplasia were recorded. The morphological and immunohistochemical findings observed in the given patient are compared with data published in the world literature.

[Role of morphology in medical education, clinical practice and research]. / Postavení morfologie ve výuce medicíny a v klinické praxi a výzkumu.

Rapid development of molecular biology, biochemistry, physiology and other sciences has diminished the previously dominant role of morphology in the theoretical part of medical studies. Morphology, closely related to various disciplines, should, however, be included in clinical lectures. Changes in the curricula would require concise and well-structured textbooks, based on recent clinico-morphological studies, for the theoretical parts of both medical and allied health care study programmes. Comprehensive textbooks are still necessary for the specific needs of clinicians and researches.