In vivo evaluation of brain damage in the course of systemic lupus erythematosus using magnetic resonance spectroscopy, perfusion-weighted and diffusion-tensor imaging

Twenty-two neuropsychiatric (NPSLE) and 13 systemic lupus erythematosus (SLE) patients with a normal appearing brain on plain magnetic resonance (MR) as well as 20 age-matched healthy controls underwent MR spectroscopy (MRS), perfusion-weighted (PWI) and diffusion-tensor imaging (DTI). In MRS NAA/Cr, Cho/Cr and mI/Cr ratios were calculated from the posterior cingulate cortex and left parietal white matter. In PWI, values of cerebral blood volume (CBV) were assessed from 14 regions, including gray and white matter. In DTI fractional anisotropy (FA) values were obtained from 14 white matter tracts including projection, commissural and association fibers. All MR measurements were correlated with clinical data. SLE and NPSLE patients showed significantly (p < 0.05) lower NAA/Cr ratios within both evaluated regions and FA values within the cingulum, as well as a tendency to cortical hypoperfusion. Compared to SLE, NPSLE subjects revealed lower FA values within a wide range of association fibers and corpus callosum. Advanced MR techniques are capable of in vivo detection of complex microstructural brain damage in SLE and NPSLE subjects regarding neuronal loss, mild hypoperfusion and white matter disintegrity. MRS and DTI seem to show the highest usefulness in depicting early changes in normal appearing gray and white matter in SLE patients.

Quantitative Evaluation of Changes in the Selected White Matter Tracts Using Diffusion Tensor Imaging in Patients with Alzheimer's Disease and Mild Cognitive Impairment

This study evaluated the damage to the extensive range of white matter tracts in patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI). Thirty-four patients with AD (mean age 71.5 yrs, MMSE 17.6), 23 patients with MCI (mean age 66 yrs, MMSE 27.4) and 15 normal controls (mean age 69 yrs, MMSE 29.8) were enrolled. Diffusion tensor imaging (DTI) was performed in 25 directions on 1.5 T MR scanner. Fractional anisotropy (FA) values were obtained with a small ROI method in several association tracts including posterior cingulum fibers, in commissural tracts (genu and splenium of corpus callosum) and projection tracts (middle cerebellar peduncles and posterior limbs of internal capsules). In MCI significant reductions of FA were found in the inferior longitudinal fascicles, left superior longitudinal fascicle and posterior cingulum fibers compared to normal controls. In AD significantly decreased FA values were detected in the same fascicles as in MCI and additionally in inferior fronto-occipital tracts and commissural tracts. In both AD and MCI the most severe changes were found within posterior cingulum fibers. No abnormalities were detected in projection tracts in both groups. Accuracy of DTI in detecting AD and MCI reached 0.95 and 0.79, respectively. FA measurements strongly correlated with neuropsychological tests. DTI is capable of depicting microstructural changes within white matter fiber tracts in dementia and may aid the differential diagnosis of AD and MCI.

Coil Embolization of Two Flow-Related Aneurysms in P1 Segment of the Posterior Cerebral Artery in a Patient with Occlusion of the Ipsilateral Internal Carotid Artery

Aneurysms of the posterior cerebral artery (PCA) are uncommon (about 1% of all intracranial aneurysms) and their neurosurgical treatment is associated with high operative risk. We report on two saccular aneurysms of the P1 segment of the right PCA, combined with occlusion of the C1 segment of the internal carotid artery (ICA) detected during routine diagnostic studies in a 58-year-old patient with slight sensory loss in the left extremities. The aneurysms were embolized during two consecutive sessions, without subsequent complications. Endovascular intervention is an efficient method in the treatment of multiple aneurysms in the P1 segment of the PCA.

Microsatellite and chromosome instability in squamous cell laryngeal carcinoma

Head-and neck squamous cell carcinoma (HNSCC) represents almost 5% of all malignancies in Europe. The aetiology of HNSCC is complex, with both genetic and mutagenic factors involved. The aim of the present study was to investigate the loss of heterozygosity (LOH), mainly at tumour suppressor loci (using markers D1S2883, D2S123, D3S1611, D5S346, D7S501, D8S254, TP53, NM23), microsatellite instability (BAT25, 26, 40) and <hidden chromosome instability> (bleomycin test) in patients with squamous cell larynx cancer. In a group of 20 patients LOH was observed mainly at the loci 3p (64.7%), 8q (71.4%), 17q (M1-30.8%, M2-25%, M3-38.5%). Despite chromosomal instability detected by bleomycin no microsatellite instability was observed.

Our own experience with CT angiography in early diagnosis of cerebral vascular malformations

Computed tomography (CT) and intraarterial cerebral angiography are essential methods in early diagnosis of cerebral vascular malformations. In recent years however non-invasive or minimally invasive methods like MR angiography and CT angiography (CTA), which could potentially replace angiography, have been developed. The aim of presented study is to demonstrate our own experience in application of CTA in early diagnosis of cerebral vascular malformations. The material consists of 86 CTA examinations performed shortly after non-traumatic intracranial haemorrhage. Angiographic correlation has been available in 23 patients and surgical one--in 31 cases. CTA studies began with serio-CT to select the optimal time between contrast injection and CT scanning. After that 100-120 ml of non-ionic contrast medium was injected intravenously (5 ml per sec.) and spiral CT acqusition was performed with the delay calculated on the basis of the serio-CT. The obtained images were postprocessed on the workstation using always MIP and in many cases also SSD and VRT reconstructions. Vascular malformations have been diagnosed in 44 of 86 CTA studies including 38 patients with aneurysms (total number 51) and 6 patients with AVMs. In 17 cases the diameter of the aneurysm did not exceed 5 mm. In all surgical cases the CTA diagnosis of the aneurysm has been confirmed. There was however one false-negative case. On the other hand in 7 patients CTA revealed the small aneurysm, despite unclear angiographic appearance. In 2 of 6 patients with CTA suspicion of AVM this diagnosis has been excluded either by angiography or surgery. Comparison of CTA and angiography in 22 aneurysms showed in 17 cases superiority of CTA in evaluation of aneurysmal neck and the relationship between aneurysm and adjacent vessels (especially with VRT and SSD reconstructions). In patients with AVMs however the evaluation of supplying and draining vessels was better with angiography. On the base of our material we can conclude that CTA is very efficient in detecting and evaluating the aneurysms. We believe that CTA can replace angiography if it reveals aneurysm in a site corresponding with location of haemorrhage on CT. In patients with suspicion of AVM value of CTA is doubtful and angiography remains the method of choice.

[Apolipoprotein E(ApoE)and tau protein in Alzheimer type dementia]

In 45 patients meeting NINCDS-ARDRA criteria for probably diagnosis of Alzheimer disease (AD), ApoE genotype and tau protein level in cerebro-spinal fluid (CSF) were determined. Frequency of e4 allele occurrence in group of AD patients was 73.3% and showed high statistic significance in comparison with control group. Increase of tau protein level in CSF was also statistically significant. No correlation in ApoE allele and tau protein level in CSF was revealed. The authors emphasize the usefulness of tau protein level measurement and determination of ApoE allele in diagnosis of Alzheimer disease.

[Poland's syndrome]

Poland's syndrome consists of the variable clinical features, but always includes unilateral aplasia of the chest wall muscles and ipsilateral anomalies of upper extremity. The incidence of Poland's syndrome, reported by different authors ranges from 1:10,000 to 1:100,000 and is observed more frequently in males than in females with the right side of the body affected more often than the left. The etiology of this syndrome is still discussed. However most of described cases were sporadic, rare familial incidence of Poland's syndrome were also presented. Therefore different etiologic factors of the Poland's syndrome are taken into account: genetic, vascular compromise during early stages of embriogenesis but also teratogenic effect of environmental xenobiotics (e.g. cigarette smoking by pregnant women). The authors present also the case of 20-years old man with inherited bilateral syndactyly with the right side aplasia of major pectoralis muscle and face asymmetry. The familial history was negative in respect to the features, associated with Poland's syndrome.

Microsatellite instability in thyroid papillary carcinoma and multinodular hyperplasia

Microsatellite instability (MSI) is a molecular landmark of mutations in DNA mismatch repair genes. The impaired efficiency of DNA repair mechanisms promotes carcinogenesis as well as contributes to tumour progression. Until now, only few studies on MSI in thyroid tumours have been published. Therefore, the aim of the present study was to investigate MSI as a possible characteristic feature of thyroid tumours. The analysis of 12 thyroid papillary carcinomas and 17 multinodular hyperplasias at 13 microsatellite loci showed MSI and loss of heterozygosity (LOH) in both types of lesion, with more alterations noted in the papillary thyroid carcinomas (in 65%) than in multinodular hyperplasia (in 35%). In carcinomas, LOH occurred more frequently than MSI, while in multinodular hyperplasia the LOH/MSI ratio is almost equal.

Bleomycin-induced chromosome aberrations in head and neck cancer patients analyzed by classical cytogenetics and FISH

Individual sensitivity to mutagens has been considered to play an important role in head-and-neck squamous cells carcinoma (HNSCC) development. The bleomycin test was introduced for establishing constitutional susceptibility to mutagens (T.C. Hsu, D.A. Johnston, L.M. Cherry, D. Ramkisson, S.P. Schantz, J.M. Jessup, R.J. Winn, L. Shirley, C. Furlong, Sensitivity to genotoxic effects of bleomycin in humans: possible relationship to environmental carcinogenesis, Int. J. Cancer 43 (1989) 403-409). Its criteria are based on scoring of chromosome aberrations (CAs, mainly breaks) in Giemsa-stained chromosomes. Fluorescence in situ hybridization (FISH) offers an easy method for analysis of translocations, acentric fragments and dicentrics. In the present study FISH was applied in the analysis of bleomycin-induced CAs of the HNSCC patients and controls. The results proved that FISH is a complementary method to the classical staining in monitoring of bleomycin-induced CAs.

The influence of GSTM1 and GSTT1 genotypes on the induction of sister chromatid exchanges and chromosome aberrations by 1,2:3,4-diepoxybutane

Cytogenetic tests - chromosome aberrations (CA), sister chromatid exchanges (SCE) and micronuclei (MN) - are most often applied in biomonitoring of the genotoxicity of potentially carcinogenic chemicals in human cells. One of the extensively studied genotoxins is diepoxybutane (DEB) - reactive biometabolite of butadiene (BD). Several studies showed a high SCE induction in human lymphocytes exposed in vitro to various concentrations of DEB. DEB also proved to be a potent inducer of chromosome aberrations and micronuclei. A bimodal distribution of SCE frequency after in vitro DEB treatment was observed. The aim of the present study was to examine the ability of DEB to induce different individual cytogenetic response measured by SCE and CA frequency. The possible influence of genetic polymorphism has also been taken into account, by including donors representing positive or null GSTM1 and GSTT1 genotypes. Our study supported the earlier results showing that DEB is an effective inducer of SCEs and CAs, causing also the decrease in replication index (RI). DEB bioactivity measured by SCE induction - but not by CA test - was significantly higher in GSTT1 negative than in GSTT1 positive donors. GSTM1 polymorphism had no influence on these endpoints. The donors GSTT1-/GSTM1+ were shown to be slightly more sensitive to DEB than GSTT1-/GSTM1- individuals. There was also observed a unimodal distribution of DEB-induced SCEs and CAs in the group, despite the fact that the experiment was performed on the lymphocytes obtained from both GSTT1 positive and negative donors.

[Aspergillus spondylodiscitis]

Four weeks after an Amanita phalloides poisoning, a 29-year-old man presented an ocular aspergillosis. One month later he developed a bilateral L5-S1 radicular syndrome. The diagnosis of aspergillar spondylodiscities was established on the basis of x-ray, CT-scan, MRI and pathology findings. Clinical and radiological improvement was obtained with fluconazole.

8q22-->qter duplication in a child with multiple congenital malformations: case report

BACKGROUND

Congenital malformation syndromes are often caused by unbalanced chromosome translocations, which appear spontaneously or may be inherited from a healthy parent being the carrier of a balanced reciprocal translocation (rcp). Breakpoints, underlying chromosome fragment exchanges, may be located at any point of any chromosome and therefore, an infinite number of different translocations is possible. Special emphasis is placed both on the clinical characterization of every rare chromosomal aberration syndrome and on the determination of its breakpoints.

OBJECTIVES

Diagnosis of a 8q22-->qter duplication in a child with multiple congenital malformations.

MATERIAL AND METHODS

We determined the karyotypes of the five members of proband's family were established by using classical cytogenetic methods on whole blood obtained by venipuncture.

RESULTS

We described a rare familial reciprocal translocation t(8; 14), observed in balanced form in mother and one healthy son, while being unbalanced in the son with congenital malformations.

CONCLUSIONS

Balanced chromosome 8 aberration carriers should be aware of the procreation risks and need genetic counseling.

[Y-specific sequences in Turner syndrome]

Turner Syndrome (TS) is the only one monosomy that occurrs+ in humans. The cytogenetics of TS is very well known from years. It has been estimated that almost 98-99% of TS foetuses end in abortion. It was suggested that the monosomy arises relatively late during embryonal development and survived TS individuals could be mosaics. It has been proved that mosaic karyotype mos 45,X/46X, + mar(Y) occurrs++ in 2% to 11% of TS patients. The patients having additional cell line containing der(Y) are at increased risk of gonadoblastoma development. In these cases gonadectomy should be considered. Therefore detection of mosaic and establishing the origin of marker chromosome (specially containing Y-specific sequences) is of special importance. The aim of present study was to detect the small mosaics, containing mar(Y) in TS patients, by using PCR and FISH techniques. Eight Y sequences for the PCR analyses as well as bicolor in situ hybridisation with painting probes for Y and X chromosomes have been applied. The positive amplification for Y-specific sequences has been detected in 7% of TS patients. Our results support the thesis that searching for the Y sequences should be introduced to routine genetic TS diagnosis.

Glutathione S-transferase M1 genotype influences sister chromatid exchange induction but not adaptive response in human lymphocytes treated with 1,2-epoxy-3-butene

Induction of sister chromatid exchanges (SCEs) by 1,2-epoxy-3-butene (monoepoxybutene, MEB), an epoxide metabolite of 1,3-butadiene, in human whole-blood lymphocyte cultures has previously been observed to depend on the glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) genotype of the blood donor. Pretreatment of lymphocyte cultures with a low dose of MEB has been shown to reduce the SCE response obtained by later treatment with a higher concentration of MEB. To investigate whether this adaptive response depends on the GSTM1 genotype of the donor, SCE induction by MEB (25 and 250 microM at 48 h for 24 h) was studied from whole-blood lymphocyte cultures of young non-smoking male and female subjects representing GSTM1 positive (n=7) and null (n=7) genotypes, with or without a MEB pretreatment (12.5 microM at 24 h). A higher mean number of induced SCEs per cell at 250 microM MEB was observed in lymphocytes of the GSTM1 null than positive donors, a statistically significant difference being obtained in the presence of the adaptive treatment (9.44 vs. 6.56; results from ethanol-treated controls subtracted). The pretreatment resulted in a statistically significant reduction in the response of the GSTM1 null group at both concentrations of MEB and in the GSTM1 positive group at 250 microM. However, there were no statistically significant differences in the adaptive response of the two genotypes. In conclusion, the present study further supported earlier findings on an increased sensitivity of GSTM1 null donors to SCE induction by MEB, suggesting that GSTM1 is involved in the detoxification of MEB in human lymphocyte cultures. As an adaptive response was observed in both GSTM1 positive and null donors, the phenomenon cannot be explained by GSTM1 induction. It may represent induction of other enzymes operating in MEB detoxification, or activation of DNA repair.

Classical and molecular cytogenetics in analysis of diepoxybutane-induced chromosome aberrations

The genotoxic properties of diepoxybutane (DEB) have been extensively studied by many authors. The most often investigated endpoints were sister chromatid exchanges (SCE) and micronuclei (MN), and less frequently, chromosome aberrations (CAs). In the present study, the analysis of CAs induced by DEB in vitro on human whole blood lymphocytes was performed by using three methods of chromosome visualisation: Giemsa-staining, GTG banding and chromosome painting (FISH). The results showed that DEB is a very efficient clastogenic agent and induces chromosome breaks and gaps as well as tri- and quadriradials (observed by using classical cytogenetic methods) together with acentrics (observed by using FISH) on the statistically significant level, as compared to controls (chi2-test, p<10-5). The analysis of GTG-banded metaphases revealed that the break-points were distributed non-randomly within the chromosomes and located mainly in 1p, 1q, 2p, 2p, 6q, 9q and 14q (p<10-6). In conclusion it can be stated, that methods applied in this work are complementary and can be used successfully for estimation of the clastogenic potential of the tested chemical.

Classical and molecular cytogenetic methods in diagnosis of a rare translocation t(3;21)

We report the characterization by traditional cytogenetic methods and fluorescence in situ hybridization (FISH) of a rare balanced reciprocal translocation t(3;21) in a male spouse connected with several miscarriages. G- and C-banding analysis of the male karyotype was suggestive of breakpoints in chromosomal bands 3q11.1 and 21p11.1. Multicolor-FISH analysis using chromosome-specific alpha-satellite probes in combination with a locus-specific bacterial artificial chromosome (BAC) from 21q22.3 allowed us both to identify the origin of centromeres in the derivative chromosomes and to establish centromere-telomere orientation of the translocated chromosome 21 segment. Characterization of the translocated chromosomes by FISH analysis permitted describing the exact karyotype of the carrier as: 46,XY,-3,-21,+der(3)(21qterO21q11. 2::3p11.2O cenO3qter),+der(21)(3pterO3p11.2::21q11.2OcenO21pte r).

[Trinucleotide repeats polymorphism of the androgenic receptor gene in the detection of carriers of androgen insensitivity syndrome]

Androgen insensitivity syndrome (AIS) is caused by mutation in androgen receptor (AR) gene. This phenomenon leads to the defect of the virilization of the external genitalia and is one of the causes of human male pseudohermaphroditism. Molecular diagnosis of AR gene mutations is very complex because of heterogeneity of AR mutations. AIS is X-linked recessive trait and therefore the simple diagnosis of AIS carriers is a very important problem. Detection of AIS carriers by using the analysis of CAG repeating sequence polymorphism of exon 1 or AR gene is reported.

[Coexistence of migraine and glaucoma-like visual field defects]

PURPOSE

Functional and morphological evaluation of the optic nerve heads in patients suffering from migraine.

MATERIAL AND METHODS

21 patients--13 women and 8 men (mean age 40 +/- 10) with neurologically confirmed diagnosis of common and classic migraine were examined. The headache history was obtained by standard questions. The patients suffered from migraine from 2 to 30 years and the frequency of attacks was from < 10 to > 100/year. Ophthalmologic examination involved evaluation of visual acuity, anterior segment, irido-corneal angle, retina and optic disc. In all cases optic disc photography, diurnal tension curve and two central visual field examinations with Octopus 101 programm G2 were performed.

RESULTS

In all cases IOP was normal (< 21 mm Hg). In 4 eyes (2 patients) there was early glaucomatous-like damage of the optic disc, without visual field defect. In most of these patients the optic nerve head looked normal, in part of them slightly pale. In 28% patients glaucomatous-like visual field defects were found (MD-3.9 dB to 6.6 dB). There was statistically significant relationship between increase of MD and frequency of migraine attacks (Mann-Withney U test, a = 0.05).

CONCLUSIONS

Static perimetry of the central visual field has high diagnostic value in ocular vasospastic syndrome. Functional dysregulation of the optic nerve head circulation in patients with migraine might be involved in the pathogenesis of normal-tension glaucoma.

Chromosome instability in head and neck cancer patients

Genetic changes play a crucial role in the process of neoplastic transformation. Mutations may occur spontaneously, but most of them (60-90%) are induced by mutagens. The epidemiological data indicate that only a part of the population exposed to mutagens/carcinogens develops cancer. Studies of the mechanisms leading to individual sensitivity to mutagens as well as tests allowing to recognize individuals susceptible to cancer have been performed. The bleomycin test is widely used for this purpose. In this classical test introduced by Hsu et al, the mean number of breaks per cell is analysed. In our study we present first results of the bleomycin test in patients suffering from head and neck cancer. In these patients, an increased number of breaks/cell (1.22 +/- 0.5 vs 0.79 +/- 0.3 in the control group) and an increased number of damaged cells (47% vs 36%) were observed. The results were also analysed in regard to the clinical stage of the disease. The data suggest that the chromosome instability does not correlate with the progression of the disease.

Debrisoquine hydroxylase gene polymorphism in neurofibromatosis type 1

Cytochrome P450 CYP2D6 polymorphism is an autosomal recessive trait leading to impaired sparteine/ debrisoquine metabolism in 5-10% of the Caucasian population. Previous studies have associated affected individuals (poor metabolizers = PM) with susceptibility to bladder cancer and various forms of leukemia. In many other cancer forms, the data remain contradictory. A PCR assay allows the convenient screening of about 90% of known mutations resulting in the PM phenotype. Since in patients with neurofibromatosis type 2, we had observed a significantly increased rate of CYP2D6 mutations leading to PM and apparently predisposing for NF2, we extended our investigation to tumor and peripheral blood samples obtained from NF1 patients. Although the number of cases investigated remains low, the study indicated that during tumor formation no changes occurred at the mutational hot spot within the CYP2D6 sequence. Moreover, no loss of heterozygosity was notable. However, the frequency of the mutated allele in the NF1 individuals is comparable to that of neurofibromatosis type 2 and above that observed in breast and colon cancer, or meningiomas.

Correlation between the adaptive response and individual sensitivity to monoepoxybutene in in vitro experiments on human lymphocytes

Individual variations in the susceptibility to mutagenic/carcinogenic chemicals depend on the activity of xenobiotic metabolizing enzymes and on DNA- and chromosome-damage repair systems. Monoepoxybutene (MEB) is a genotoxic metabolite of 1,3-butadiene (BD), which has been classified as a probable carcinogen in humans. The purpose of the present study was to investigate by in vitro experiments on human whole blood lymphocytes (WBL), whether an individual sensitivity to MEB correlates with the adaptive response to the tested agent. In the analyzed group, 8.3% of blood donors were relatively sensitive to MEB. The comparison of SCE induction in cultures pretreated and not pretreated with an adaptive dose (AD) of MEB showed, that there was an adaptive response to MEB. The adaptive response in the group of relatively sensitive donors was similar to that of the relatively resistant ones. This result suggests that individual sensitivity to the tested agent and adaptive response depend on different biological mechanisms.

[Cytogenetic analysis in couples with spontaneous abortions]

Cytogenetic studies were performed in 129 couples with the history of recurrent spontaneous miscarriages. In 8 couples (6.2%) chromosome aberrations were found The most frequent aberrations were reciprocal translocations (in 6 couples). Pericentric inversion of chromosome 9 was detected in 3 couples (2.3%) while the chromosome polymorphism was observed in 20% of analyzed cases.

[Sarcoidosis with involvement of the central nervous system]

Two cases of lungs and mediastinal lymph nodes sarcoidosis with involvement of central and peripheral nervous system were described. In one patient the vascular type of neurosarcoidosis was diagnosed, in another-the inflammatory type, with pyramidal and cerebellar symptoms and severe peripheral changes. Both cases were illustrated with MRI scans.

[Herpes simplex meningoencephalitis in an infant observed during an epidemic of enteroviral infections of the nervous system]

An infant with Herpes simplex meningoencephalitis which occurred during an epidemic of enteroviral neuroinfections is described. Clinical and laboratory signs of meningitis as well as preceding aphtous oropharyngeal inflammation, initially suggested an enteroviral etiology. The appearance of signs of encephalitis with focal neurologic disturbances and the results of brain imaging by computed tomography, primarily the detection of temporoparietal areas of hypodensity, raised the possibility of HSV infection. Thanks to early specific treatment with acyclovir, the infant recovered from meningoencephalitis and 4 months later presented only minor neurological sequelae (slight left hemiparesis). The diagnosis of Herpes simples meningoencephalitis was confirmed by detecting IgM and IgG anti-HSV antibodies in the serum and cerebrospinal fluid both at the beginning and after 10 days of treatment and also by a eightfold rise of the anti-HSV-1 antibody level in serum. The authors emphasize the role of brain imaging (computed tomography and magnetic resonance) in the differential diagnosis of viral nervous system infections and suggest early treatment with acyclovir in case of suspicion of HSV-encephalitis.

[CT of early ischemic lesions of the brain]

Thirty CT studies performed in the first 24 hours after the onset of the ischemic stroke were analyzed. In all cases direct or indirect diagnosis of the ischemic infarction was possible on the basis of CT images. The main symptom was slight decreased density in the infarction area which occurred in 80% of the patients. The second important sign was mass effect (63.3% of the patients). The significance of the early CT diagnosis of the ischemic lesions increases due to the development of the methods of the early antithrombotic treatment, especially intraarterial thrombolysis.

[Analysis of difficulties in CT diagnosis of hypodense brain tumors]

The author analysed CT findings in 30 cases of hypodense brain tumours confirmed histopathologically or with MR. Differential diagnosis of these tumours is difficult and should include ischaemic, traumatic and inflammatory lesions. However after detailed analysis of CT and clinical findings correct diagnosis was obtained in 86.7% of cases. The most frequent histopathological diagnosis in our series was low-grade astrocytoma but one third of the confirmed tumours proved to be malignant. Follow-up CT studies and MR imaging can be helpful in doubtful cases.

[Multiple sclerosis coexisting with myasthenia]

In a male patient multiple sclerosis was found to coexist with myasthenia. The symptoms of muscle fatiguability and of central nervous system damage developed at the same time. Multiple sclerosis was the predominating disease, especially in later stage of the disease. The authors discuss the possibility of a common immunological substrate for both conditions.

The reversibility of CT brain changes in alcohol dependence

Control CT assessments of the brain of 15 alcohol dependent patients who showed an improvement in their clinical state were performed after a mean of 16 months. A partial decrease of the widening of cerebral sulci and the third ventrical was noticed. Also, the neuroradiological pictures of the vermis and cerebellum were seen to improve in most patients.

Sister-chromatid exchanges and cell-cycle kinetics in the lymphocytes of workers occupationally exposed to a chemical mixture in the tyre industry

Cytogenetic studies of clinically healthy workers employed in the rubber industry showed an increase in chromosome aberrations (CAs), sister-chromatid exchanges (SCEs) and a decrease in proliferation indices (PIs). The aim of the present study was to establish, using the SCE and PI tests, genotoxic effects of hazardous chemicals in the rubber industry. An increase in mean SCEs in the lymphocytes of vulcanizers as compared to controls was observed. Since the PI in the exposed group was insignificantly decreased as compared to the controls, it could be concluded that the SCE test is the most sensitive cytogenetic test for the detection of a genotoxic effect of chemicals in the rubber industry. There was no evidence in the present study that the genotoxic effect of chemicals in the rubber industry was enhanced by cigarette smoking.

[Ischemic cerebellar and brain stem lesions in CT findings]

The author analysed CT studies of 117 patients with ischaemic lesions of the cerebellum and brainstem. The clinical appearance in these cases is often unspecific. This was confirmed by false clinical diagnosis in most patients. CT diagnosis is particularly difficult in cases with mass effect which was found in 24.8% of the patients. Follow-up CT studies can help in proper diagnosis. The territory of the superior cerebellar artery was most frequently involved in the cerebellum, while the territory of the paramedian perforating in the brainstem. In 26.5% of the patients ischaemic lesions of the cerebellum and/or brainstem were bilateral, in 39.3% were accompanied by cerebral infarcts. It can be concluded that they are the component of general vascular insufficiency of the whole bain.

[Analysis of the reversibility of CT brain changes in alcohol dependent patient]

Control CT assessments of the brain of 15 alcohol dependent patients who showed an improvement in their clinical state were performed after a mean of 16 months. A partial decrease of the widening of cerebral sulci and the third ventrical was noticed. Also, the neuroradiological pictures of the vermis and cerebellum were seen to improve in most patients.

Nonrandom distribution of breakpoints in the karyotypes of workers occupationally exposed to benzene

The distribution of the breakpoints in the karyotypes of workers occupationally exposed to benzene was tested. Fifty-six workers exposed to benzene were investigated cytogenetically. A significant increase in chromosome aberrations was observed. The distribution of the breakpoints in the karyotypes of examined workers was significantly nonrandom (p less than or equal to 0.001). The breakpoints accumulated mainly on chromosomes 2, 4, and 7.

Cytogenetic studies of workers from the rubber industry

Lymphocytes from 21 vulcanizers from a tire factory were analyzed for the presence of chromosome aberrations (CAs), sister-chromatid exchanges (SCEs) and for proliferation indices (PIs). An increase in the frequencies of CAs and SCEs and a decrease in PIs were observed. Cytogenetic parameters were correlated with age, smoking habits, and duration of occupational exposure. From the present study it can be concluded that cigarette smoking enhances the genotoxic effects of mixtures of chemicals to which workers in the rubber industry are exposed.

[Genetic studies of brain gliomas]

Tumour origin and evolution currently is viewed as comprising a series of specific genetic events that take place in target cells and their clonal descendants. These events can be recognized at two levels: cytogenetic and molecular. The genetic results can be used as diagnostic and prognostic markers of neoplastic diseases. However, till now reports on the karyotypic characteristics of brain tumors are far from numerous. The most frequent cytogenetic alterations observed in primary brain tumors are losses or gains of chromosomes or chromosomal regions and presence of double minute chromosomes. Enhanced expression of several cellular oncogenes on human glioma cells lines were observed also.

1,3-Butadiene and its epoxides induce sister-chromatid exchanges in human lymphocytes in vitro

Sister-chromatid exchanges (SCEs) were induced in human lymphocytes by 1,3-butadiene and its epoxides 3,4-epoxy-1-butene and 1,2:3,4-diepoxybutane. After a pulse treatment of 2 h, 1,3-butadiene produced a weak but reproducible increase in SCEs both with and without S9 mix. The response was similar in cultures of whole blood and of isolated lymphocytes. The 2 epoxide metabolites of butadiene, studied in whole-blood lymphocyte cultures without exogenous metabolic activation, were highly active SCE inducers. The lowest effective concentrations of butadiene, monoepoxybutene, and diepoxybutane were 2000 microM, 25 microM and 0.5 microM, respectively. A slight but dose-dependent increase in SCEs was also observed without an exogenous metabolic system after a 48-h treatment with 1,3-butadiene. Already the lowest concentration tested (500 microM) was effective. Again, the response was similar in cultures of whole blood and isolated lymphocytes, suggesting that the lymphocytes are capable of metabolically activating 1,3-butadiene.

Sister-chromatid exchanges induced by 1.3-butadiene and its epoxides in CHO cells

Sister-chromatid exchanges (SCEs) were analyzed in CHO cells after pulse treatment with 1,3-butadiene, 3,4-epoxy-1-butene (monoepoxybutene) and 1,2:3,4-diepoxybutane (diepoxybutane). A weak dose effect was observed after exposure to 1,3-butadiene but only in the presence of S9 mix. Monoepoxybutene and diepoxybutane were highly effective in inducing SCEs at concentrations of 0.1-1 microM both in the presence and in the absence of S9 mix. At higher concentrations the response was more pronounced without S9 mix.

CT appearance of bilateral, acute thrombosis of the main cerebral arteries

Acute thrombosis within the lumen of the intracranial artery may occasionally be demonstrated on precontrast CT. The hyperdensity follows the course of the occluded segment of the vessel and an area of low attenuation in the territory of the involved artery is usually present, consistent with infarction. Usually, a single vessel is involved; occlusion of multiple branches occurs less commonly. This report demonstrates a case of diffuse bilateral thrombosis of the main arteries of the anterior circle of Willis.

Localization of breakpoints in the karyotype of workers professionally exposed to benzene

Cytogenetic analysis was carried out on peripheral blood lymphocytes of 33 workers professionally exposed to benzene for 10-26 years. In the examined group structural chromosome aberrations were found in 147 metaphases (4.7%). Statistical analysis has shown that the distribution of breakpoints was not random. Chromosomes 2, 4 and 9 are almost twice as susceptible to breaks, while chromosomes 1 and 2 are almost twice as susceptible to gaps, as would be expected based on a random distribution of damage among chromosomes.

[Indications for CT examination of the head in infants and young children]

308 CT scans of the head in children below 3 years of age were analysed. 70% of children were younger than 1 year. The most common findings in this age group were subdural effusions (usually no wider than 10 mm) and hydrocephalus. The authors conclude that the indications to CT scan should be more rigorous because of the high dose of the ionizing radiation applied. Ultrasonography should be the initial investigation in the children with persistent fontanellae+ as it has a similar diagnostic efficiency without harmful effect to the child body.