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A tris(alkoxo)pyridine-augmented Wells-Dawson polyoxometalate (nBu4N)6[WD-Py] (WD = P2V3W15O59(OCH2)3C, Py = C5H4N) was functionalized with phthalocyaninato metal moieties (MPc where M = Y or Yb and Pc = C32H16N8) to afford (nBu4N)4[HWD-Py(MPc)] compounds. High-resolution mass spectrometry was used to detect and identify the hybrid assembly. The magnetism studies reveal substantial differences between M = Yb (monomeric, single-ion paramagnetism) and M = Y (containing dimers, radical character). The results of electronic paramagnetic resonance spectroscopy, SQUID magnetometry, and magnetochemical calculations indicate the presence of intramolecular charge transfer from the MPc moiety to the polyoxometalate and of intermolecular charge transfer from the MPc moiety of one molecule to the polyoxometalate unit of another molecule. These compounds with identified VIV ions represent unique examples of transition-metal/lanthanide complex-POM hybrid compounds with nonphotoinduced charge transfer between electron donor and acceptor centers.

The two first representatives of phthalocyaninato (Pc) lanthanide-ligated polyoxovanadate cages {[V12O32(Cl)](LnPc)n}n-5 (n = 1 or 2, Ln = Yb3+) were synthesised and fully characterised. These magnetic complexes form two-dimensional self-assembled monolayers exhibiting electrical conductivity on gold substrate surfaces, as assessed by using an EGaIn tip.

The electronic structure and magnetism of mixed-valence, host–guest polyoxovanadates {X@VIV/V22O54} with diamagnetic (X =) ClO4− (Td, 1) and SCN− (C∞v, 2) template anions are assessed by means of two theoretical methods: density functional theory and effective Hamiltonian calculations. The results are compared to those obtained for another member of this family with X = VO2F2− (C2v, 3) (see P. Kozlowski et al., Phys. Chem. Chem. Phys., 2017, 19, 29767–29771), for which complementary data are also acquired. It is demonstrated that the X guest anions strongly influence the electronic and magnetic properties of the system, leading to various valence states of vanadium and modifying V–O–V exchange interactions. Our findings are concordant with and elucidate the available experimental data (see K. Y. Monakhov et al., Chem. – Eur. J., 2015, 21, 2387–2397).

The black-green solid (NEt4)5[V16O38(Br)]·2H2O (1) was synthesized by the pH-controlled reaction of a mixed-valence precursor (NH4)8[H9VIV12VV7O50]·11H2O with Et4NBr in water under aerobic conditions. Compound 1 crystallizes as pseudomerohedral three-domain twins with pronounced pseudosymmetry and very large voids accommodating the majority of the countercations and solvent water molecules. The central structural motif of 1 is represented by a spherical, mixed-valence, host–guest vanadium-oxo cluster [VIV/V16O38(Br)]q with q = 5–, 4–, or 6–, exhibiting dominant antiferromagnetic and weaker ferromagnetic exchange interactions. The intriguing valence-state and dependent magnetic behavior of this compound have been unraveled by weighted model Hamiltonian calculations combined with diffraction, quantum mechanical, spectroscopic, and spectrometric techniques. It appears that 1 features a hitherto not identified and initially not evident VIV/VV average ratio of 8:8 which corresponds to an average charge q = 5– ...

The electronic structure and magnetism of the recently synthesised mixed-valent {VVO2F2@VIV/V22O54} (1) host–guest polyoxovanadate envisaged as a potential building block of a molecule-based quantum computer are analysed using density functional theory (DFT) and effective Hamiltonian calculations. The form of the t–J like effective Hamiltonian has been inspired by the acquired DFT data, and the valence state used in DFT calculations has been suggested by the fits to the experimental magnetic data with the effective Hamiltonian. This self-consistent approach breaks through the magnetochemical limitations of vanadium-oxo cluster 1, giving results fully concordant with the experiment and allowing us to determine the valence state of 1, which contrary to other members of this host–guest family appears to feature 9 valence electrons.

Ribonucleases (RNases) play a critical role in RNA processing and degradation by hydrolyzing phosphodiester bonds (exo- or endonucleolytically). Many RNases that cut RNA internally exhibit substrate specificity, but their target sites are usually limited to one or a few specific nucleotides in single-stranded RNA and often in a context of a particular three-dimensional structure of the substrate. Thus far, no RNase counterparts of restriction enzymes have been identified which could cleave double-stranded RNA (dsRNA) in a sequence-specific manner. Here, we present evidence for a sequence-dependent cleavage of long dsRNA by RNase Mini-III from Bacillus subtilis (BsMiniIII). Analysis of the sites cleaved by this enzyme in limited digest of bacteriophage Φ6 dsRNA led to the identification of a consensus target sequence. We defined nucleotide residues within the preferred cleavage site that affected the efficiency of the cleavage and were essential for the discrimination of cleavable versus non-cleavable dsRNA sequences. We have also determined that the loop α5b-α6, a distinctive structural element in Mini-III RNases, is crucial for the specific cleavage, but not for dsRNA binding. Our results suggest that BsMiniIII may serve as a prototype of a sequence-specific dsRNase that could possibly be used for targeted cleavage of dsRNA.

In this paper we review our results of comprehensive study of molecular nanomagnets recently synthesized in the form of the chromium-based molecules and bimetallic copper-containing chains as well as we present some new findings. We focus on effects of anisotropy, geometry and frustration appearing in various thermodynamic properties of the nanoscale magnets which are described by Heisenberg-like spin models and simulated by accurate numerical methods. We show that bond-dependent exchange anisotropy is needed to model magnetic torque in the Cd-doped chromium ring. We argue that only in the limit of infinite rings (n -> infinity) frustration can be considered as the opposite to bipartiteness in the odd numbered (3

In order to verify two microscopic models of the molecular nanomagnet Cr7Cd we analyze a number of thermodynamic quantities calculated for two sets of parameters. The first model, with only single ion anisotropy, was established on the basis of the thermodynamic properties (by fitting susceptibility and magnetization) whereas the second, with single ion and bond-dependent exchange anisotropies, was based on the inelastic neutron scattering and EPR spectra. The calculations are performed by means of non-perturbative, numerically exact quantum transfer matrix technique on large scale parallel computers. We demonstrate that the predictions of the models are consistent in the region of small magnetic fields which do not exceed 10 T and differ significantly in higher fields. Comparison with the experiment leads to a conclusion that better modeling of magnetic torque requires more complex microscopic model with single ion and bond-dependent exchange anisotropies.

Effects of magnetic frustration in the model of nine-membered antiferromagnetic s = 3/2 molecular spin ring are investigated. We use a Heisenberg spin model with nearest-neighbor interactions, single-ion anisotropy and with tunable bond defect leading to continuously varying topology: from closed to open ring. In order to identify a frustrated phase we calculate the full energy spectrum of the model and a number of thermodynamic quantities at low temperature. The calculations are performed by means of numerically exact methods: quantum transfer matrix and exact diagonalization. It is shown that total and local magnetizations, nearest-neighbor spin correlations and spin fluctuations can serve as consistent frustration signatures. Magnetizations and spin-spin correlations are reduced in the frustrated phase whereas fluctuations and correlations of fluctuations increase. The ground state in a frustrated phase is a m = 1/2 doublet and in the non-frustrated phase a m = 3/2 doublet. In the system studied bipartiteness is not opposite to frustration as there are regions in the parameter space for which the system is neither bipartite nor frustrated.

We fitted the data obtained from the susceptibility measurement performed on polycrystalline samples with two different sets of microscopic parameters. One set (a) contains only single ion anisotropy and the other (b) both single ion and exchange anisotropy. None of them can be favored on the basis of powder experiment. We demonstrated by means of quantum transfer matrix and exact diagonalization calculations that parameters with only one type and those comprising two types of anisotropy lead to qualitatively different behavior of magnetic susceptibility and torque calculated for a mono crystal. On the microscopic level me observe that the first anti-crossing gap between the ground and first exited states vanishes when two types of anisotropies (single ion and exchange) of different orientation (easy axis and easy plane) and similar magnitude are present in the system.

Magnetic resonance diffusion tensor imaging (DTI) of control and injured spinal cord of rats in vivo during first 6 h after the trauma was reported. DTI and histopathological results were compared. The aim of this work was to correlate the presence of damage of rat spinal cord with statistically significant changes in the apparent diffusion tensor components, in order to find the parameters that are useful in the visualization of the injury. Apparent diffusion tensor weighted data were measured in vivo 1 h after traumatic injury induced by a controlled weight drop on healthy and injured rat spinal cords for defined dozen regions of interest. Significant alternations in the injured regions of gray matter and white matter were detected. The differences in gray matter can be explained on the basis of cytotoxic edema due to ischemia and they are confirmed by the histological observations of neurons. The white matter changes in diffusional attributes are associated with the destruction of the nerve microstructure by the mechanical implant.

Crystals of (Et4N)6 [(VO2F2)HV22O54] are prepared by mixing Et4NBF and (H4N)8 [H9V19O50]·11H2O in the molar ratio of 8.7:0.39 in aqueous solution (80 °C, 72 h, 79% yield).

We study supervised learning and generalisation in coupled perceptrons trained on-line using two learning scenarios. In the first scenario the teacher and the student are independent networks and both are represented by an Ashkin-Teller perceptron. In the second scenario the student and the teacher are simple perceptrons but are coupled by an Ashkin-Teller type four-neuron interaction term. Expressions for the generalisation error and the learning curves are derived for various learning algorithms. The analytic results find excellent confirmation in numerical simulations., Latex, 21 pages, 9 figures, iop style files included

Mixed-valence polyoxovanadates(IV/V) have emerged as one of the most intricate class of supramolecular all-inorganic host species, able to encapsulate a wide variety of smaller guest templates during their self-assembly formation process. As showcased herein, the incorporation of guests, though governed solely by ultra-weak electrostatic and van der Waals interactions, can cause drastic effects on the electronic and magnetic characteristics of the shell complex of the polyoxovanadate. We address the question of methodology for the magnetochemical analysis of virtually isostructural {V(IV/V) 22 O54 }-type polyoxoanions of D2d symmetry enclosing diamagnetic VO2 F2 (-) (C2v ), SCN(-) (C∞v ), or ClO4 (-) (Td ) template anions. These induce different polarization effects related to differences in their geometric structures, symmetry, ion radii, and valence shells, eventually resulting in a supramolecular modulation of magnetic exchange between the V(3d) electrons that are partly delocalized over the {V22 O54 } shells. We also include the synthesis and characterization of the novel [V(V) O2 F2 @HV(IV) 8 V(V) 14 O54 ](6-) system that comprises the rarely encountered discrete difluorovanadate anion as a quasi-isolated guest species.

Diffusion tensor imaging (DTI) of the control and mechanically injured spinal cord of a ratin vitro andin vivo are reported.In vitro experiments were done on a home-built 6.4 T magnetic resonance microscope. Results for formaline-fixed samples show significant differences in diffusion tensor components between gray matter and white matter of the control spinal cord. Moreover, it is shown that already 6–10 min after the injury DTI can detect changes in water diffusion in areas extending far beyond the region of primary tissue damage.In vivo experiments were performed using a 9.4 T Magnex magnet and Bruker Medspec imaging system. Good-quality DTI images, free from motion artifacts were obtained. Results from control samples confirm differences in water diffusion between white matter and gray matter, observedin vitro. In vivo experiments show that characteristic changes in water diffusion observedin vitro 6–10 min after injury are preserved 60–360 min after injury, without significant alteration during this time.

) atoms in a dense sodium vapour irradiated by nanosecond laser pulses tuned near the 3S→4P transition was investigated. It was observed that the population of Na(4P) atoms remained high only within the laser pulse, in spite of the relatively long lifetime of the 4P level (110.ns)The 3P1/2 level, which is populated as a result of cascade transitions from the higher levels, reached the highest population several nanoseconds after the laser shot. The fast population changes are explained by cascade-stimulated transitions between the excited atomic levels.

Two non-perturbative numerically exact methods: exact diagonalization and quantum transfer matrix are applied to computationally complex Heisenberg-like spin models of ring shaped molecular nanomagnets and implemented in the high performance computing environment. These methods are applicable to the wide class of ring-shaped nanomagnets. For the hypothetical antiferromagnetic nanomagnet Ni\(_{12}\) the influence of single-ion anisotropy on the ground states is investigated. For Cr\(_8\) it is demonstrated that the alternation of the nearest-neighbor bilinear exchange couplings leads to small changes in the magnetic torque with respect to the uniformly coupled system. Specific heat and entropy for Cr\(_8\) are showed to be good indicators of crossing fields. The applicability of the Lande rule to both systems is checked.

The effective parallelization of processing exploiting the MPI library for the numerically exact quantum transfer matrix (QTM) and exact diagonalization (ED) deterministic simulations of chromium-based rings is proposed. In the QTM technique we have exploited parallelization of summation in the partition function. The efficiency of the QTM calculations is above \(80\,\%\) up to about \(1000\) processes. With our test programs we calculated low temperature torque, specific heat and entropy for the chromium ring Cr\(_8\) exploiting realistic Hamiltonian with single-ion anisotropy and the alternation of the nearest neighbor exchange couplings. Our parallelized ED technique makes use of the self-scheduling scheme and the longest processing time algorithm to distribute and diagonalize separate blocks of a Hamiltonian matrix by slave processes. Its parallel processing scales very well, with efficiency above \(90\,\%\) up to about 10 processes only. This scheme is improved by processing more input data sets in one job which leads to very good scalability up to arbitrary number of processes. The scaling is improved for both techniques when larger systems are considered.

In order to verify two microscopic models of the molecular nanomagnet Cr7Cd we analyze a number of thermodynamic quantities calculated for two sets of parameters. The first model, with only single ion anisotropy, was established on the basis of the thermodynamic properties (by fitting susceptibility and magnetization) whereas the second, with single ion and bond-dependent exchange anisotropies, was based on the inelastic neutron scattering and EPR spectra. The calculations are performed by means of non-perturbative, numerically exact quantum transfer matrix technique on large scale parallel computers. We demonstrate that the predictions of the models are consistent in the region of small magnetic fields which do not exceed 10 T and differ significantly in higher fields. Comparison with the experiment leads to a conclusion that better modeling of magnetic torque requires more complex microscopic model with single ion and bond-dependent exchange anisotropies.

Background. Problems encountered during revision hip arthroplasty are presented, based on 30 years of experience at the Orthopedic Clinic of the Medical University of Lodz.br /Material and methods. During this period of time 96 cases (5,13%) with aseptic hip loosening were diagnosed. All patients were evaluated clinically based o the Merle d'Aubigne-Postel criteria, and radiologically by means of De Lee and Gruen migration zones.br /Results. In our material hip loosening was most frequently observed in cases where a McKee-Farrar hip prosthesis had been used, and in cases with a PM uncemented acetabulum or uncemented Mittelmeier pin.br /Conclusions. The study showed that surgical technique plays the most significant role in aseptic loosening of hip replacement. The aseptic loosening of hip prostheses should be diagnosed early, and revision hip arthroplasty should be performed as soon as possible. This surgery must be preformed in specialized centers with adequate equipment and a team of experienced surgeons.

The use of bone cement during total hip prosthesis implantation despite it's advantages triggers of some local and general complications. The paper presents and classifies most cement related complications, with special attention to vessel complications. This paper includes an external vein injury, which occurred 5 years after a total hip replacement procedure. Chronic erosion and mechanical stress of the iliac vein by a cement hook was the cause of this complication. It has been stress that most vascular complications are a result of imperfect surgical technique.

The issue of a stabile, long lasting bone-implant interface is still very valid. One of the new models of uncemented hip prosthesis is the Bicontact prosthesis made by Aesculap. This four-part endoprosthesis offers two types of cups: threaded München type and spherical Plasmacup type. The prosthesis stem is a wedged type stem, porous in the proximal type. The aim of this paper was to evaluate the value of Bicontact prosthesis in treatment of coxarthrosis. Our material consisted of 69 patients (38 female and 31 male) with 72 operated hips. Average age of the patients was 50.8 years. The mean follow-up was 24.5 months. Clinical and radiological evaluation according to Merle d'Aubine-Postel classification with Charnley's modification yielded 88% very good and good results. In 11 hips a similar complication was noted--fracture of the femur during final hammering of the prosthesis stem into the medullary canal. This was immediately repaired by circular wire fixation without any influence on the final result. This complication was observed during the first procedures. The learning curve of surgical technique allowed us to avoid this complication during subsequent procedures. We concluded that type of hip prosthesis was is very useful in in treatment of coxarthrosis.

Heterotopic ossification is the most common complication after THR. The authors present the distribution of frequency of ectopic ossification after cementless THR using Mittelmeier and Parhofer-Mönch prosthesis and it's influence on THR outcome. 151 hip joints were evaluated with a follow-up period of more than 2 years. All procedures were performed by a lateral approach. The ectopic ossification was verified according to the Brooker classification. Clinical evaluation was performed according to the d'Aubigne-Postel method in Charnley's modification. The 3rd degree ectopic ossification was found in 14 hip joint and 4th degree ectopic ossification in 2 hip joints (together 10.6%). The positive correlation between the degree of ossification (3rd and 4th) and the decrease of range of motion of the hip joint along with an increase in pain after THR was found.

The results are presented of MRI studies of the brain and spinal cord in patients with neurological symptoms in the course of certain diseases of the haemopoietic system (leukaemias, lymphomas). The analysis showed that MR images, although not specific, can be very useful for the evaluation of the intensity and topography of haematological lesions in the central nervous system. However, the diagnosis of these processes is not easy. In the differential diagnosis focal lesions of vasogenic origin, infections and radiation-induced lesions should be considered, and in cases of lymphoma--metastases are a possibility.

Ashkin-Teller type perceptron models are introduced. Their maximal capacity per number of couplings is calculated within a first-step replica-symmetry-breaking Gardner approach. The results are compared with extensive numerical simulations using several algorithms., Comment: 8 pages in Latex with 2 eps figures, RSB1 calculations has been added

The authors report a case of central pontine myelinolysis in a woman aged 30 years addicted to alcohol since at least 30 years. In the diagnosis the principal role was played by MRI. Attention is called to the disproportion between massive brainstem lesion and relatively low extent of neurological symptoms and signs. The patient had a several-weeks alcohol detoxication treatment and general supportive treatment. During that tine the neurological signs regressed nearly completely which suggests considerable reversibility or compensation of brainstem lesions in this syndrome.

A 41-years old male patient is reported who had spastic paresis of all extremities, and evidence of peripheral motor neuron damage. He had been treated with steroids for 10 years after erroneous diagnosis of multiple sclerosis. The final diagnosis was a congenital fissure of C2 and C3 arches with spinal cord compression in cervical part. After operation some improvement of the neurological status was obtained.

The aim of the study was establishing of correlations between the age of patients and their present and past diseases on one hand and the presence and intensity of leukoaraiosis (LA) on the other hand. The studied material comprised 91 patients hospitalized between Jan 1 1995 and June 15 1996 in whom features of LA were found on CT or MRI examination. Women and patients aged over 70 years prevailed in the group. Clinical analysis was based on neurological findings and routine diagnostic investigations. The intensity of LA lesions was assessed by means of a four grade scoring system known in literature. The analysis showed that higher grades of LA were more frequent on older patients: 14 had grade IV LA and 80 or more years of age. The greatest number of the patients had grade III LA and most of them were in the age range 70-80 years. Arterial hypertension was present in 64% of the patients, and more frequently it was associated with LA in younger patients. Stroke and myocardial infarction were given by 31% an 33% of the patients respectively in the history. Several had more than one stroke. Diabetes was found in 21 patients. Ischaemic brain episodes were the most cause of hospitalization.

The anatomy, function and injuries of the anterior cruciate ligament were presented. The authors reviewed some technical problems concerning the intra-articular reconstruction of ACL using artificial prostheses, chemically treated allografts and xenografts or combinations of various materials. There was pointed out that none material was found to meet the criteria to be superior to autogenous graft of the middle one third of the patella tendon with its attached bony insertions.

The paper reports results of treatment for 5 posterior dislocations of the shoulder in 4 patients. Closed reduction was successful in 2 cases (2 days and 14 days after injury). Spontaneous reduction after removal of the Desault plaster cast 3 weeks after injury was observed in one case. Two patients with inveterate dislocation have been operated on. The defect within humeral head was filled with an allogenic bone graft in one patient and by lesser tuberosity transposition in another. Modified Constant score was used for clinical evaluation at the follow-up ranging from 5.5 months to 56 months (mean 30.4 months). Two excellent and one good result were achieved in conservatively treated cases. After surgery one result was rated poor (allograft case) and one good (lesser tuberosity transposition).

Lacunar stroke accounts for 20-25% of all ischaemic strokes. It is believed that the prognosis in this stroke is relatively good, with annual mortality being 9.8% to 11.3%. In the analysis of the Warsaw Stroke Register this mortality was much higher--about 25%. The purpose of the present study was to assess the factors increasing the probability of death in lacunar stroke based on a one-year follow-up of 113 patients (67 males and 48 females), mean age 67.3 +/- 11.2 treated at the II Department of Neurology, Institute of Psychiatry and Neurology. The total one-year mortality was 23%. In the group of patients dying in that year hypertension was found in 88% and diabetes in 27%, while in the surviving group these diseases were found in 72% and 18% respectively. The differences between groups were not significant. Considering the effect of other risk factors (age, fitness status assessed with modified Barthel index) it was demonstrated that the risk of death increased with increasing age (relative risk 1.03, 95% CI 1.001-1.05) and with the degree of dependence on the help of others, Barthel index60 (RR = 1.49.95%, CI 1.24-1.66). In the analysis of the effect of antiaggregation treatment the mortality was lower in aspirin-treated patients (300 mg daily) with cumulated annual survival rate 79.8 as compared to the not treated patients in whom it was 58.2. The difference was not significant, probably due to small number of cases.

MR imaging of the head was performed in forty schizophrenics (DSM-IV). Mental status was evaluated before and during 8-weeks of neuroleptic treatment. Cortical atrophy in frontal and temporal regions was found in 40% of subjects. They were older, had longer history of schizophrenia, were less active professionally and were more frequently hospitalized. Patients with and without cortical atrophy in MRI did not differ in the severity of schizophrenic psychopathology at baseline. During neuroleptic treatment negative schizophrenia symptoms were significantly better diminished in patients without cortical atrophy than in subjects with cortical atrophy in MRI; this regarded specially the severity of emotional blunting. Clinical improvement after 8-weeks of neuroleptic administration was less favorable in patients with cortical atrophy.

The universal critical point ratio $Q$ is exploited to determine positions of the critical Ising transition lines on the phase diagram of the Ashkin-Teller (AT) model on the square lattice. A leading-order expansion of the ratio $Q$ in the presence of a non-vanishing thermal field is found from finite-size scaling and the corresponding expression is fitted to the accurate perturbative transfer-matrix data calculations for the $L\times L$ square clusters with $L\leq 9$., Comment: RevTex, 4 pages, two figures

An Ashkin-Teller neural network, allowing for two types of neurons is considered in the case of low loading as a function of the strength of the respective couplings between these neurons. The storage and retrieval of embedded patterns built from the two types of neurons, with different degrees of (in)dependence is studied. In particular, thermodynamic properties including the existence and stability of Mattis states are discussed. Furthermore, the dynamic behaviour is examined by deriving flow equations for the macroscopic overlap. It is found that for linked patterns the model shows better retrieval properties than a corresponding Hopfield model., Comment: 20 pages, 6 figures, Latex with postscript figures in one tar.gz file

Clinical records of 89 patients with lacunar stroke were reviewed, to evaluate the occurrence of neurological syndrome and to correlate the frequency of its signs with the localization of ischaemic lesions seen in neuroimaging examinations. "Pure" motor paresis (50%) and sensory-motor paresis (27%) were the most common clinical syndromes. The localization in putamen and corona radiata (37%), or in anterior part of the internal capsule and in the head of the caudate nucleus (35%) were the most frequent sites of localization. In the group of patients with lesions in anterior part of internal capsule or with lesions in putamen and corona radiata "pure" motor paresis was the most common clinical syndrome. Additionally, in the group of patients with lesions in putamen and corona radiata sensory motor paresis was also frequently observed (44%). During one year of follow-up 22 patients died. Dysarthria and disability (Barthel Index60) were the independent predictors of one year mortality. Non-neurological complications were the main cause of death.

In forty schizophrenic (or schizophreniform disorder) patients diagnosed according to DSM-IV, the magnetic resonance imaging was performed. The T2 relaxation time was measured in selected brain regions from the dorsolateral prefrontal cortex as well as in amygdala. These results were compared with clinical parameters regarding severity of psychopathology and improvement after neuroleptic treatment. The mean T2 values of grey matter of right inferior frontal gyrus were significantly higher in patients with schizophreniform disorders (those patients were clinically diagnosed as suffering from cycloid psychoses) than in other types of schizophrenia. The T2 values of this region correlated inversely with the severity of negative symptoms before treatment. The T2 values of gray matter of left inferior frontal gyrus correlated positively with the severity of schizophrenic symptoms before treatment. Mean T2 values of left amygdala were significantly higher in patients showing less favorable improvement after neuroleptic treatment in comparison to those who improved better. No correlation was found between the presence of brain atrophy and T2 values in brain regions studied. The results allow to suggest that the measurement of T2 relaxation time might reveal interesting relations between clinical picture and neuroradiologic findings in schizophrenia, however clinical significance of such parameters still requires further elaboration.

In 40 schizophrenic patients, various criteria of clinical improvement after neuroleptic treatment were compared in order to establish correlations between improvement after treatment and some clinical and MRI parameters. Three ways of evaluation of clinical improvement (CGI scale, PANSS index, percentage of improvement) correlated strongly with one another. Only the distribution of numbers of patients with different clinical improvement evaluated by the use of PANSS index was not statistically significant. Clinical improvement, evaluated with all three methods, significantly correlated with basal PANSS score as well as with the severity of positive symptoms and affective blunting, but not with the severity of schizophrenia negative symptoms. Only clinical improvement with the use of CGI demonstrated significantly better improvement in patients who had good previous response to neuroleptics. This particular method of clinical improvement evaluation, in contrast to other two methods, failed to reveal better response to neuroleptics among patients with no cortical atrophy found in MRI. Among patients with different improvement after treatment, evaluated with the use of all three methods, selected MRI parameters did not show significant differences with the exception of CGI improvement which correlated positively with the intensity of signal in T2-weighted image of gray matter in left medial frontal gyrus.

The authors reviewed early clinical results in two groups of patients treated by arthroscopy-assisted (group I) and miniarthrotomy (group II) anterior cruciate ligament reconstruction. An autogenous midthird patellar tendon was used in all cases. Both groups were similar in regard to age, sex and type of injury; the same postoperative rehabilitative protocol was used. The data collected included total surgery time, blood loss, pain medication use, length of hospital stay, Lachman test results at 2, 6 and 12 weeks postoperatively; pivot shift test supplemented Lachman test at 6 months follow-up. Two statistically significant differences were found only: the blood loss was smaller in group I and surgery time was shorter in group II. Range of motion was better in group I only initially; at three months follow-up no differences were noted. The study results suggest that both open and arthroscopically assisted ACL reconstruction with midthird patellar tendon graft yield similar early clinical results.

Central pontine myelinolysis now is believed to be a polyetiological syndrome. Our case was diagnosed clinically due to typical neurological symptoms occurred in the course of the treatment hyponatraemia and hypokaliaemia. Forty six years old woman an alcohol abuser, with liver dysfunction was admitted to neurological department in the first grand mall attack. She was tetraplegic, with signs of alcoholic polyneuropathy simultaneously hyponatraemia and hypokaliaemia were observed. Two weeks after normalization of electrolytic alterations, symptoms of brain stem lesion appeared. Based on MRI and clinical symptoms the diagnosis of central pontine myelinolysis was suggested and proved on autopsy. Electrolytic disturbances and treatment are discussed.

A case of multisymptomatic brain stem injury, possibly during subacute viral infection, in a 27-year-old man is reported. Two MR imaging at the time of regression of disease symptoms demonstrated in the medulla stabilized lesions of the type of central myelinolysis without damage to the corticospinal pathways. During four years of follow-up the neurological status was improving gradually, but involuntary movements of the mandible and face muscles make speech difficult.

Clinical records were reviewed to analyse occurrence of hypertension and other risk factors that may predispose to the development of lacunar stroke. The comparison of risk factors associated with deep, small, ischaemic lesions of the brain (revealed in 67% by CT, in 31% by MRI and in 2% by autopsy) and large superficial or superficial and deep ischaemic lesions (diagnosed in 89% by CT, 4% by MRI and 7% by autopsy) was done. Hypertension, treated and untreated, was more frequent in lacunar stroke, but the difference was not statistically significant. Statistically significant difference was found in large stenotic lesions of internal carotid artery, which were more common in patients with large superficial or superficial and deep lesions (watershed area) and in moderate stenotic lesions of internal carotid artery, which were more common in patients with lacunar stroke. The results suggests that lacunar stroke may be caused by cerebral embolism from carotid sources.

Headache with paroxysmal vertigo were induced by cough in a case of the Arnold-Chiari type I malformation. The authors suggest that exertional headache and posterior cranial fossa symptoms of unclear aetiology may indicate presence of the syndrome, and the availability of magnetic resonance imaging made possible the detection of the malformation.