Coliform bacteria isolated from recreational lakes carry class 1 and class 2 integrons and virulence-associated genes.

AIMS: To characterize the integron-harbouring Gram-negative bacteria in recreational lakes, with focus on the genetic content of integrons, antimicrobial resistance profiles and virulence-associated genes. METHODS AND RESULTS: The presence and structure of integrons in coliform bacteria isolated from the water of four recreational lakes located in Poznan, Poland, was determined by PCR method. Antimicrobial resistance testing was done by disc diffusion method. Virulence-associated genes in integron-bearing Escherichia coli isolates were detected by PCR. A total of 155 integron-bearing strains of coliform bacteria were cultured. Sequence analysis showed the presence of dfrA7, aadA1, dfrA1-aadA1, dfrA17-aadA5 and dfrA12-orfF-aadA2 gene cassette arrays in class 1 integrons and dfrA1-sat2-aadA1 in class 2 integrons. Higher frequency of integron-positive bacteria and higher antimicrobial resistance ranges were noted in colder months (January and November) compared with spring and summer months. The integron-harbouring E. coli carried up to nine virulence-associated genes, with the highest frequency of kpsMT (84.6%) and traT (783%), coding for group 2 capsule and determining human serum resistance respectively. CONCLUSIONS: Integron-bearing multidrug resistant coliform bacteria carrying virulence genes are present in waters of recreational lakes. SIGNIFICANCE AND IMPACT OF THE STUDY: This study presents antimicrobial resistance and virulence-associated genes in integron-bearing coliform bacteria present in the waters of recreational lakes, which showed that multidrug resistant bacteria with virulence traits might pose a threat to public health. Moreover, the presence of genes typical for enterotoxigenic and Shiga toxin-producing E. coli is a concern.

Immunohistochemical studies in diagnosis of the uncommon cases of tumours of the central nervous system.

There is a growing evidence that tumoursof the central nervous system (CNS) exhibit some immunophenotypic aberrations pointing to the multipotential cell differentiation. However, the immunohistochemistry remains still very helpful in differential diagnosis and nosologic classification of the CNS neoplasms. The purpose of this paper is to present the immunomorphological pattern of some rare neoplasms of neuroepithelial origin that over last years were recognised and classified as new clinico-pathological entities. Histological and immuniohistochemical features of three cases including pleomorphic xanthoastrocytoma, chordoid glioma and central neurocytoma are reported with special references to immunohistochemical differentiation of these neoplasmswith other tumours of similar morphology but different histogenesis.

A case of cystic form of angiomatous meningioma with prominent microvascular pattern mimicking haemangioblastoma.

A surgical case was reported of an unusual angiomatous variant of meningioma with predominant microvascular component and extensive cystic changes. The tumour was incidentally detected in a 79-year-old woman who was admitted to the hospital because of a head injury. The CT scan revealed in addition to bilateral subdural haematomas a large-sized (5 x 5 x 4 cm) multicystic tumour with a solid contrast-enhancing nodule in the right frontal region. Microscopically, the tumour tissue was composed predominantly of a dense meshwork of small, capillary-like and thin-walled dilated blood vessels and a relatively small component of intervening meningotheliomatous tumour cells. The resemblance of the presented case to some rare cases of cystic meningioma which were formerly classified as a haemangioblastic variant of meningioma or transitional forms between meningioma and haemangioblastoma is briefly discussed.

Quinolinic acid and sigma receptor ligand: effect on pyramidal neurons of the CA1 sector of dorsal hippocampus following peripheral administration in rats.

Male Wistar rats, weighing 200-220 g, were used in the study. Quinolinic acid and racemic pentazocine were administered alone or together. Quinolinic acid was administered intraperitoneally (i.p.) in a dose of 60 mmol, racemic pentazocine intramuscularly in a dose of 2 mg/kg, once every 24 h for 8 days. The control group received 1 ml of saline i.p. once daily for 8 days. Pentazocine alone produced no signs of alteration in the hippocampal formation. Quinolinic acid produced neurotoxic effect in the CA1 area of the hippocampal formation. The presence of the dark-degenerated pyramidal cells was a common sign of a delayed excitotoxic effect. Pentazocine added to quinolinic acid markedly attenuated the neurotoxic effect of quinolinic acid. In such cases, only single dark degenerated cells were seen.

A case of progressive supranuclear palsy with widespread appearance of neurofibrillary changes and associated senile and vascular brain lesions.

A case of progressive supranuclear palsy in association with vascular and senile brain changes in a 70-year-old woman is described. Neuropathological study with immunocytochemistry anti-tau-1 revealed widely distributed neurofibrillary tangles (NFT) and neuropil threads (NT) in several subcortical nuclei, including pallidum, subthalamic nucleus, substantia nigra, brain stem tegmentum and, to a lesser extent, in cerebral cortex. Moreover, the tau-1 positive NT were observed in many fiber bundles of the subcortical white matter. All NFT and NT were immunonegative against ubiquitin. Electron microscopic study disclosed straight filaments of about 15 nm diameter in the axoplasm of large myelinated fibers. Ultrastructural findings and appearance of abnormal tau in the white matter indicate an extension of characteristic cytoskeletal pathology with subcortical projection fibers involvement in the presented case.

Phenotypic characteristics of GFAP-immunopositive oligodendroglial tumours Part I: immunohistochemical study.

Oligodendrogliomas are believed to derive from oligodendrocyte lineage but the expression of different immunohistochemical markers indicates some variability in their differentiation potency. It has been documented that some heterogeneity of the tumour cells exists and that oligodendrogliomas can display a spectrum of histological, immunohistochemical and fine structural features. The expression of glial fibrillary acidic protein (GFAP) in various types of neoplastic cells in oligodendroglial tumours has been well established, however the nature of these cells in relation to tumour malignancy remains controversial. The current histopathological and immunohistochemical study (with a panel of antibodies for GFAP, vimentin, S-100 protein, MBP, NSE) has been performed on biopsy specimens from 12 cases of GFAP-immunopositive oligodendroglial tumours to evaluate their phenotypic characteristics. The majority of tumours showed a variable pattern of GFAP expression in morphologically different tumour cells responding to typical neoplastic oligodendrocytes (gliofibrillary oligodendrocytes-GFOC), miniature form of gemistocytes (minigemistocytes) and neoplastic or reactive astrocytes. The majority of cases exhibited negative staining for vimentin whereas there was no evident correlation between GFAP expression and other immunohistochemical markers. The present immunohistochemical findings support the opinion that the majority of GFAP-positive neoplastic cells in oligodendroglial tumours represent the transitional cell types between oligodendroglial and astrocyte lineage. The difficulties in differential diagnosis of oligodendroglial tumours exhibiting the various patterns of GFAP expression are emphasised.

Xanthomatous changes in atypical and anaplastic meningiomas. Light and electron microscopic investigations.

Xanthomatous changes may occur in meningiomas of different histological type, however their incidence in combination with histological features of atypical or anaplastic meningioma has not been previously documented. In this report we present clinicopathologic, immunohistochemical and ultrastructural studies in the surgical cases of two atypical and three anaplastic meningiomas exhibiting prominent xanthomatous changes. In all tumors the xanthomatous cells were seen in association with typical meningioma structures such as meningothelial whorls or psammoma bodies as well as within the tumor parts displaying pleomorphism, patternless growth, increased cellularity, presence of necroses and mitoses or brain invasion. Ultrastructural study revealed a wide-range of lipid-containing cells, reflecting a continuum of gradual transition between polymorphic meningioma cells and xanthomatous cells. Commonly, the lipidized cells exhibited different degrees of plasmalemmal interdigitations and desmosomal junctions. Our study allowed us to confirm the meningothelial origin of xanthomatous cells in atypical and anaplastic meningiomas. Moreover, the ultrastructural observations of lysosomes in the majority of xanthomatous cells and the immunoreactivity for the CD68 antigen indicated their macrophage characteristics. It seems that a mixed meningeal/macrophage nature of xanthomatous cells can be related to the functional and structural multipotentiality of the primary leptomeningeal cells.

Subependymal giant cell astrocytoma: clinical, histologic and immunohistochemical characteristic of 3 cases.

Three cases of subependymal giant cell astrocytoma (SEGA) in the women aged 23, 26, and 36 years were reported. Two of them had no clinical evidence of tuberous sclerosis complex (TSC) and the one woman presented apparent mental retardation. All patients manifested sudden clinical onset with symptoms of elevated intracranial pressure due to tumor of lateral ventricles and obstructive hydrocephalus. At surgery, the neoplasm was removed totally in one case and resected partially in 2 cases. Histologically, the tumors were composed of large polygonal cells with vesicular nuclei, prominent nucleoli and glassy eosinophilic cytoplasm, intermingled with spindle and small cells. In addition, multinucleated and bizarre giant cells were present, but they were very numerous in one case only. The tumor cells revealed in all cases variegated immunoreactivity for glial fibrillary acidic protein (GFAP), S-100 protein, vimentin (VIM) and neuron-specific enolase (NSE), with stronger expression of VIM than GFAP in 2 cases. Immunostaining of neurofilament proteins and synaptophysin was negative. The results suggest rather astroglial incomplete or aberrant differentiation and maturation than neuronal differentiation of tumor cells. The immunohistochemical variations of SEGA in asymptomatic TSC cases and those associated with tuberous sclerosis are discussed.

Necrosis and apoptosis of tumor cells in embolized meningiomas: histopathology and P53, BCL-2, CD-68 immunohistochemistry.

The preoperative embolization of intracranial meningiomas, used in selected patients to reduce tumor vascularity and blood loss during surgery, may produce ischemic changes and/or tumor necrosis. The aim of the present study was to determine the relationship between necrosis within the embolized tumors and expression of two apoptosis-associated proteins (p53 and bcl-2) and macrophage-monocyte CD-68 antigen. Four biopsy specimens of embolized meningiomas, including three benign and one atypical tumor, were revived histopathologically and examined immunohistochemically using the monoclonal antibodies to p53, bcl-2 proteins and CD-68 antigen. The observations showed that the p53-immunopositive cells were most frequent in perinecrotic and ischemic areas than in non-ischemic, intact parts of tumors. The bcl-2 protein was expressed predominantly in well-preserved regions lacking ischemic tumor cells, whereas in close proximity to the necrosis only a few bcl-2 positive cells could be detected. Anti-CD-68 immunostained cells were distributed around or within the necrotic foci. Our results indicate that the expression of apoptosis-related proteins correlates with ischemic cell injury induced by preoperative tumor embolization.

Quinolinic acid and GABA-B receptor ligand: effect on pyramidal neurons of the CA1 sector of rat's dorsal hippocampus following peripheral administration.

In this study we evaluated the effect of baclofen on excitotoxic action of quinolinic acid in hippocampus following its prolonged systemic administration in rats. Male Wistar rats, weighing 200-220 g, were used in the study. Quinolinic acid and baclofen were administered alone or together. Quinolinic acid was administered intraperitoneally (i.p.) in a dose of 60 mmol, baclofen in a dose of 2 mg/kg, by gastric tube, once daily for 8 days. The control group received 1 ml of saline i.p. once daily for 8 days. Quinolinic acid alone produced neurotoxic effect in the CA1 area of the hippocampal formation. The presence of the dark-degenerated pyramidal cells was a common sign of a delayed excitotoxic effect. Baclofen added to quinolinic acid markedly attenuated the neurotoxic effect of quinolinic acid. In such cases, only some dark degenerated cells were seen. Baclofen alone resulted in alterations in some pyramidal cells in the hippocampal formation.

Olfactory neuroblastoma (esthesioneuroblastoma) and esthesioneuroepithelioma: histologic and immunohistochemical study.

Two cases of olfactory neuroblastoma (ONB) representing two morphological variants of the tumor are described. Case 1 exhibited a neuroblastoma-like histological pattern corresponding to the usually reported type of ONB--the esthesioneuroblastoma, whereas in case 2 a very rare variant of ONB-the esthesioneuroepithelioma was recognized. The histological and immunohistochemical differences between the cases are discussed with regard to still controversial opinions concerning the subclassification of ONB and the histogenesis and clinical prognosis of these tumors.

Phenotypic characteristics of GFAP-positive oligodendroglial tumours. Part II: ultrastructural study.

Five cases of anaplastic oligodendrogliomas containing numerous GFAP-positive cells have been analysed by electron microscopy to establish the fine structural characteristics of neoplastic cells. Ultrastructurally, all tumours have revealed monotonous appearance typical of oligodendrogliomas, however some structural variability, particularly with reference to astrocytic differentiation, has been observed. The majority of neoplastic cells have shown the fine structural features of oligodendrocytes, accompanied by various numbers of intermediate cytoplasmic filaments. These filaments have been usually distributed in the perinuclear, less often in the peripheral, parts of the cytoplasm. The cells exhibiting features common to both oligodendroglial and astroglial cells might be regarded as an intermediate morphological form between these two cell types. True neoplastic astrocytes could be encountered only sporadically. The present electron microscopic studysupports the opinion that GFAP-positive oligodendroglial tumours contain heterogeneous neoplastic cell populations with the transitional cell types between oligodendroglial and astroglial lineage.

Immunohistochemical study of myelin-specific proteins in pt rabbits.

The cellular/regional expression of myelin-specific proteins: PLP, MBP, CNP-ase, MAG and MOG was investigated in the brains of 14 and 42 days old control and pt-mutant rabbits. The results showed severe reduction in expression of PLP protein, the known molecular target of pt mutation. The minor differences in immunostaining of the other studied myelin-connected proteins between normal and mutant rabbits confirmed once more the deficient and delayed myelination in pt brain. No signs of the increased retention of neither PLP nor any other protein in pt oligodendrocytes were evidenced in this study.

Pattern of tau-1 and ubiquitin immunoreactivity in the white matter of temporal lobe in senile and with Alzheimer's disease brains.

Immunostaining pattern of the temporal white matter with anti-tau-1 and anti-ubiquitin was different in examined cases of Alzheimer's disease (AD) and normal aging. Tau-1 immunoreactivity was observed in the white matter of all AD brains, in loosely dispersed neuropil threads (NT), a few neurofibrillary tangles (NFT) and scattered glial cells, whereas in majority of senile brains the white matter was immunonegative. Ubiquitin immunoreactivity characterized by dot-like structures, evenly distributed throughout the white matter, was observed in all cases examined being more prominent in AD than in senile brains. The dot-like structures were unrelated to tau-1 immunostaining pattern, as neither NT and NFT nor glial cells were ubiquitin labeled. It was concluded, that different immunostaining with both antibodies used reflects variable pathological changes identified mostly in nerve fibers. There are neurofibrillary changes manifested by tau-1 labeled NT. However, they differed from cortical NT by lack of ubiquitin immunostaining. Non-filamentous ubiquitin-positive depots represent presumably nonspecific nerve fiber changes related to various pathological events, including AD and aging process.

A case of the subacute brainstem encephalitis.

A case of brainstem encephalitis of undetermined etiology is reported in 66-year-old woman who had a sudden onset of illness with left abducens palsy, nystagmus and ataxia. The symptoms progressed to complete paralysis of eye movements, dysphagia and left hemiparesis with generalized hyperreflexia. Examination of CSF, CT scan and MRI of the brain were normal. The patient died 4 months after onset of disease. Neuropathologic study disclosed in the brainstem numerous perivascular and nodular inflammatory cell infiltrations composed predominantly of lymphocytes T and B. Most intensive inflammation concerned midbrain and pontine tegmentum and to a lesser degree medulla oblongata, pontine nuclei and cerebellar nuclei. Basal ganglia, cerebral and cerebellar cortex were unaffected. Neuropathological finding was reminiscent of brainstem encephalitides related to viral infection or to paraneoplastic syndrome. However, HSV-1, EBV, and CMV antigens were not detected by immunohistochemistry, as well as evidences of malignancy were not present in this case.

Quinolinic acid: effect on the nucleus arcuatus of the hypothalamus in the rat (ultrastructural evidence).

Quinolinic acid was administered intraperitoneally to male Wistar rats in a dose of 60 mmol, once daily for 8 days. By electron microscopy, in quinolinic acid-treated rats, the neuronal cell bodies in the arcuate nucleus had features of increased cellular activity, but some damage of neuronal cell bodies was also evident.

The effect of quinolinic acid administered during pregnancy on the nigro-striatal complex of rat's offspring: ultrastructural investigation.

The nigro-striatal complex of rat's offspring was ultrastructurally examined after quinolinic acid administration to mothers during the gestation period, in order to mimick the congenital metabolic disturbances, resulting from an excess of quinolinic acid within foetal tissues. Hence, quinolinic acid was administered to mothers intraperitoneally in a dose of 60 mmol, once daily, throughout the entire gestation period. Brain specimens were taken on day 5 after birth, from experimental and control animals. Within the nigro-striatal complex there can be distinguished the more characteristic neuronal cell body alterations, and the more toxic effect as the edema signs and the retardment of the neuronal cell body maturity. In the substantia nigra, both swollen and dark-degenerated neuronal cell bodies have been identified, while in the striatum the latter forms predominated. The maturation of neuronal cell bodies was retarded, mainly within the striatum.

Histological and ultrastructural changes in the rat brain following systemic administration of picolinic acid.

Picolinic acid was administered intraperitoneally in a dose of 30, 60, or 100 mmol, once every 24 h for 8 days. Histologically, under normal conditions as well as when picolinic acid was administered in a dose of 30 mmol the brain formations exhibited characteristic features. When picolinic acid was administered in a dose of 60 mmol or 100 mmol, the alterations were profound and developed selectively in hippocampus, being much less intense in the substantia nigra and striatum. In such cases, injuries of neuronal cell bodies were accompanied by symptoms of spongiosis. Within the hippocampus, the neuronal cell body injury was selectively restricted to the hilar and CA3 regions of stratum pyramidale. Tissue spongiosis was more intense at the granular layer, particularly within the hilus and in the mossy fiber area at CA3. Histochemically, a variable intensity of the reaction of succinic and alpha-glycerophosphate dehydrogenases was demonstrated. A decrease in their activities was observed in areas where the neuronal cell body injuries and spongiosis took place. No changes in the Ca-ATP-ase activity in brain formation after picolinic acid treatment were observed. Ultrastructurally, the changes within substantia nigra were manifested by neuronal cell bodies of the dark type and dendritic degenerations. Also less damaged neuronal cell bodies were seen. They were swollen, depleted of polyribosomes with dilated elements of RER and altered mitochondria. Some of the dendritic profiles were swollen with lucent cytoplasm. Most of the boutons in synaptic contact zones were unchanged. Most presynaptic terminals which were in junction with dark dendrites were swollen with or without crystal-like aggregates of synaptic vesicles.

[Light microscopic and ultrastructural features of nerve fibres in glomus tumor in two patients with long-term pain]. / Mikroskopowy i ultrastrukturalny obraz wlókien nerwowych w klebczaku u 2 pacjentów z wieloletnimi bólami.

Morphologic features of nerve fibres in two cases of glomus tumour, localized in thigh skin of 57- and 72-year-old men are reported. In the patients, the paroxysms of severe pain occurred 10 and over 11 years respectively. Histological, immunohistochemical and ultrastructural examination revealed tumour cells with features resembling that of epithelioid smooth muscle cells of normal glomus body. In addition, NF-immunopositive nerve fibres were identified in connective stroma of the tumour. Ultrastructural examination revealed bundles of thin, nonmyelinated axons, surrounded by Schwann cell cytoplasm. The majority of axons were under 0.5 micron in diameter and contained densely packed neurofilaments, whereas only few axons of larger diameter exhibited electron-lucent axoplasm with granular and clear vesicles. The bundles of nonmyelinated nerves were observed always within spaces filled by collagen fibrils and did not show any special relationship to glomus cells.

[Experimental studies on a hereditary central nervous system disease in PT rabbits. V. Clinical syndrome in generations 1-10]. / Badania doswiadczalne nad choroba dziedziczna osrodkowego ukladu nerwowego na modelu królika "PT". V. Obraz kliniczny w pokoleniach I--X

Sex-linked mutation designated by the genetic symbol pt causes in rabbits a syndrome of parkinsonian tremor and spastic paralysis of extremities. Clinical phenotypes were observed in 10 geenratoins. Fig. 1 shows the types of matings. The appearance in pt rabbits of clinical improvement permitting to use them for reproduction and abortive or asymptomatic cases appearing in later generations are connected by the authors with the fact the a healthy rabbit had been introduced into the flock (rabbit No 84432). This rabbit had the genetic trait M modifying the clinical course of the pt syndrome. In Mm heterozygotes clinical improvement was observed, in MM homozygotes abortive and asymptomatic courses occurred. The M trait must be transferred by autosomes. The hypothetical M trait explains the clinical phenomena observed in the pt group but it requires still confirmation by specially planned experimental matings.