Acute transient inflammatory leukoencephalopathy in HIV

HIV-related acute inflammatory leukoencephalopathy of undetermined origin (AIL) is characterized by abrupt onset of symptoms generally associated with focal brain lesions and inflammatory CSF findings. A previously asymptomatic 31-year-old HIV+ woman presented with acute cognitive difficulties, right hemiparesis and dysphasia. Brain MRI showed a large contrast-enhancing lesion in the left frontal lobe; brain biopsy revealed an inflammatory process. No etiological agent was found in blood, CSF or brain tissue. The patient was given systemic steroids and gammaglobulins and put on HAART. Clinical conditions progressively and completely recovered. Further brain MRI showed the shrinkage of the lesion with no contrast enhancement. Our case could be classified as AIL in HIV resembling ADEM pattern and highlights the importance of taking into consideration. ADEM in the diagnostic process of HIV-related leukoencephalopathy even if the typical features are lacking, as immunodeficiency could modify both presentation and disease course.

Total endoscopic approach to the cauda in a patient with a tight filum

In this report we describe a patient with a tight filum associated with a small concentric lipoma that was treated by cutting the filum terminale through a totally endoscopic approach. Our approach required the creation of a midline surgical corridor provided by the placement of a telescopic self-retaining retractor over the ligamentum flavum at L5-S1, under endoscopic control. The ligamentum was partially removed, the dura and the arachnoid opened and the filum terminale and the roots of the cauda exposed. After neurophysiological confirmation of the absence of neural structures the filum was coagulated and cut, the dura was closed by a continuous suture and sealed with fibrin glue. The entire surgery was performed under the illumination and magnification provided by a rigid endoscope working in an aerial environment. This case shows that the cauda can be explored and the filum terminale cut with a minimally invasive endoscopic approach that does not significantly compromise the structural integrity of the spine, requires only a short dural incision, therefore reducing the risk of postoperative cerebrospinal fluid leakage, and allows the use of multiple surgical instruments in an aerial environment.

Comparative expression profiles of ShcB and ShcC phosphotyrosine adapter molecules in the adult brain

Shc family of adaptor molecules has been demonstrated to play an important role during the transition from proliferating neural stem cells to postmitotic neurons. Previous studies from our group demonstrated a progressive decrease of ShcA levels occurring in coincidence with the end of embryonic neurogenesis and neuronal maturation, being ShcB and ShcC the major Shc molecules expressed in the mature brain. A growing body of evidence indicates that ShcB and ShcC are neuronal specific molecules exerting important roles in neuronal survival and phenotypic stability thus becoming potential attracting target molecules for development of drugs for interfering with brain demises. Here, we examine the expression pattern of ShcB and ShcC in neuronal populations composing the adult central and peripheral nervous system, in order to better elucidate their roles in vivo. We found a heterogeneous and peculiar presence and subcellular localization of ShcB and ShcC in specific neuronal populations, enlightening a potential specific requirement of these two molecules in the survival/maintenance of defined neuronal subtypes.

Lack of enantioselectivity of herpes virus thymidine kinase allows safer imaging of gene delivery

Herpes simplex virus thymidine kinase (HSV-TK) is widely used in gene therapy. The enzymatic activity of HSV-TK may be traced in vivo by specific radiopharmaceuticals in order to image transgene expression. However, most of these radiopharmaceuticals are toxic per se or after activation by HSV-TK, and therefore do not represent ideal molecules for clinical applications and repeated imaging. Unlike human cytosolic TK, HSV-TK is not enantioselective and can efficiently phosphorylate both D and L enantiomers of beta-thymidine. Here we show that, after phosphorylation by HSV-TK, tritiated L-beta-thymidine (LT) is selectively retained inside the cells in vitro and in vivo. We used the in vivo accumulation of radioactive phosphorylated LT to image the HSV-TK-positive cells inside a transplantable murine brain tumour after inoculation of cells producing retroviruses carrying HSV-TK. Owing to their unnatural enantiomeric conformation, phosphorylated LT metabolites are very poorly processed by mammalian enzymes, thus leading to increased cellular retention and minimal toxicity. The ability to image cells expressing the HSV-TK gene by using radiolabelled LT, without damaging the cells accumulating the phosphorylated L-nucleoside, will be important to monitor the levels and spatial distribution of therapeutic vectors carrying HSV-TK.

Dexamethasone inhibits the anti-tumor effect of interleukin 4 on rat experimental gliomas

Retroviral-mediated gene transfer of the IL-4 gene into experimental gliomas can cause tumor rejection, supporting the clinical use of this form of gene therapy for glioblastomas (GBM). In a clinical setting, the administration of dexamethasone (dex) is a standard procedure for GBM patients. This led us to examine the effects of dex on IL-4 gene therapy. We injected intracranially Fischer 344 rats with phosphate-buffered saline, 9L gliosarcoma cells mixed with E86.L4SN(200) cells (retroviral producer cells, RPC, transducing IL-4 cDNA) and 9L cells mixed with PA317.STK.SBA cells (control RPC expressing the HSV-tk gene). The rats from each group were treated with 0, 50, 100 or 250 microg dex/kg/day released by osmotic pumps implanted subcutaneously. While 80-100% of rats receiving 9L cells mixed with IL-4 RPC and not treated by dex survived for at least 2 months following tumor injection, only 50% and 17% of rats receiving 50 or 100 microg/kg/day of dex, respectively, reached this time point. These results indicate that dex significantly diminished the anti-tumor effect of IL-4. Thus, in a clinical setting, IL-4 gene transfer should be performed when low levels of dex are administered or in the absence of dex.

Shc signaling in differentiating neural progenitor cells

Previously we found that the availability of ShcA adapter is maximal in neural stem cells but that it is absent in mature neurons. Here we report that ShcC, unlike ShcA, is not present in neural stem/progenitor cells, but is expressed after cessation of their division and becomes selectively enriched in mature neurons. Analyses of its activity in differentiating neural stem/progenitor cells revealed that ShcC positively affects their viability and neuronal maturation via recruitment of the PI3K-Akt-Bad pathway and persistent activation of the MAPK pathway. We suggest that the switch from ShcA to ShcC modifies the responsiveness of neural stem/progenitor cells to extracellular stimuli, generating proliferation (with ShcA) or survival/differentiation (with ShcC).

Upregulation and activation of Stat6 precede vascular smooth muscle cell proliferation in carotid artery injury model

The role of signal transducers and activators of transcription (STAT) proteins in modulating proliferation and differentiation of various cell types in the hematopoietic system and the central nervous system has been well established. In contrast, the pathophysiological role of these proteins in vascular proliferative diseases has remained unproven, despite in vitro observations emphasizing the involvement of the STAT system in mediating vascular smooth muscle cell (VSMC) proliferation. On the basis of our previous observations demonstrating the occurrence of a specific modulation of Stat6 protein during the proliferative, migratory, and differentiation phases of the developing brain, we investigated whether Stat6 protein is present and modulated in arterial tissue challenged by perivascular injury. The time course of expression and localization of Stat6 after arterial injury was analyzed by immunohistochemistry, Western blot analysis, and confocal microscopy. Six hours after injury, the expression of Stat6 was markedly increased. This overexpression preceded the onset of VSMC proliferation and was downregulated starting from 7 days after injury, coincident with the decline of VSMC proliferation. Moreover, early after injury, Stat6 was predominantly localized at the nuclear level, denoting its functional activation. Conversely, Stat6 staining at later time points was largely cytosolic, suggesting silencing effects of this signaling pathway. These data indicate that Stat6 signaling may contribute to the modifications of gene expression underlying VSMC activation in the context of acute vascular proliferative diseases.

Gene therapy of experimental brain tumors using neural progenitor cells

Glioblastomas, the most frequent and malignant of primary brain tumors, have a very poor prognosis. Gene therapy of glioblastomas is limited by the short survival of viral vectors and by their difficulty in reaching glioblastoma cells infiltrating the brain parenchyma. Neural stem/progenitor cells can be engineered to produce therapeutic molecules and have the potential to overcome these limitations because they may travel along the white matter, like neoplastic cells, and engraft stably into the brain. Retrovirus-mediated transfer of the gene for interleukin-4 is an effective treatment for rat brain glioblastomas. Here, we transferred the gene for interleukin-4 into C57BL6J mouse primary neural progenitor cells and injected those cells into established syngeneic brain glioblastomas. This led to the survival of most tumor-bearing mice. We obtained similar results by implanting immortalized neural progenitor cells derived from Sprague-Dawley rats into C6 glioblastomas. We also documented by magnetic resonance imaging the progressive disappearance of large tumors, and detected 5-bromodeoxyuridine-labeled progenitor cells several weeks after the injection. These findings support a new approach for gene therapy of brain tumors, based on the grafting of neural stem cells producing therapeutic molecules.

Expression of the JAK and STAT superfamilies in human meningiomas

OBJECT

The goal of this study was to investigate whether the janus kinase/signal transducer and activator of transcription (JAK/STAT) signal transduction pathway is present and active in meningiomas. The results of these investigations are important for all meningioma therapies that, similar to interferon-alpha-2B (IFNalpha-2B), depend on activation of this pathway for their effect. The authors were interested in evaluating the importance, if any, of the JAK/STAT pathway in the biology and therapy for these tumors.

METHODS

Total proteins were extracted from 17 meningioma samples and the levels of JAKs and STATs were determined by using Western blot analysis. Levels of these proteins in meningiomas were compared with those found in normal dura. The JAKs and STATs (with the exception of Jak3 and Tyk2) were present both in the dura and in the meningiomas studied. In tumors JAK and STAT levels were always significantly higher than those found in normal dura. Differences in relative levels were found when meningiomas were subdivided according to the current neuropathological criteria and the highest levels were found in transitional meningiomas. The authors also investigated, using tyrosine-phosphorylated Statl and Stat3 antibodies, whether STATs were activated in meningiomas and normal dura in vivo. Their results indicate that both Statl and Stat3 are phosphorylated in vivo in meningiomas and in the dura. Furthermore, in vitro experiments in which two independent short-term cultures obtained from freshly dissected meningioma samples were used indicated that Statl and Stat3 are phosphorylated in response to treatment with IFNalpha-2B. Exposure of meningioma cells to IFNalpha-2B leads to nuclear translocation of tyrosine-phosphorylated Statl and Stat3, as demonstrated by immunocytochemical analysis.

CONCLUSIONS

The results of this study indicate that the JAK and STAT families of proteins are important effectors in brain tumors and support the idea that the effects of IFNalpha in vivo are direct and not mediated by the immune system. This suggests a role for modulation of STAT transcription factors in inhibiting meningioma cell proliferation.

Eradication of rat malignant gliomas by retroviral-mediated, in vivo delivery of the interleukin 4 gene

Overexpression of interleukin 4 (IL-4) can impair the tumorigenicity of glioma cells, but direct evidence of its antitumor efficacy after in vivo gene transfer into malignant gliomas has not been provided. To test this, we first injected into the brain of Sprague Dawley rats a 1:1 mixture of C6 rat glioblastoma cells and psi2.L4SN20 or E86.L4SN50 retroviral producer cells (RPCs), secreting 20 and 50 ng of IL-4/5 x 10(5) cells/48 h, respectively. Twenty-seven and 56% of rats receiving injections with these low- or medium-level IL-4 RPCs, respectively, survived tumor injection, whereas control rats died in about 1 month. E86.L4SN50 RPCs coinjected with 9L gliosarcoma cells into syngeneic Fischer 344 rats yielded similar results. A novel IL-4 RPC clone expressing higher levels of IL-4, E86.L4SN200, coinjected with 9L cells increased to 75% the fraction of long-term survivors and induced tumor regression in 50% of rats when injected into established 9L gliosarcomas. Cured rats developed an immunological memory because they rejected a challenge of wild-type 9L cells into the contralateral hemisphere. Magnetic resonance imaging was used to monitor 9L and C6 gliomas and gave direct evidence for tumor rejection in treated rats. Immunohistology showed inflammatory infiltrates in IL-4-treated tumors in which CD8+ T lymphocytes were more abundant, although CD4+ T lymphocytes, B lymphocytes, and macrophages were also present. Overall, these findings suggest that IL-4 gene transfer is a new, promising approach for treating malignant gliomas.

Members of the JAK/STAT proteins are expressed and regulated during development in the mammalian forebrain

The presence and activation of members of the Janus Kinases/Signal Transducers and Activator of Transcription proteins in response to specific cytokines is currently the focus of intense investigation in the hematopoietic system. Although some evidence suggests that cytokines might play an important role in brain development and brain pathologies, very limited information is available on the presence of the JAK/STAT proteins in the Central Nervous System. Here we provide Western blot and immunohistochemistry data on the presence of Jak2 in vivo in the immature brain, its expression being greater in early stages of the embryonic life and gradually diminishing towards adulthood. Conversely, Jak1 was found expressed at a lower level compared to Jak2 and not modulated during brain maturation. Western blot data also show that specific members of the STAT family, the cytoplasmic substrates of the Janus Kinases, are present in vivo and that the extent of their expression is modulated differently at various stages. In particular, Stat6 protein levels were markedly attenuated at advanced stages of differentiation, as well as in the adult brain, with respect to early embryonic life. On the contrary, Stat3 levels did not vary. Analysis of Statl and Stat5 proteins showed a more complex expression pattern. These data indicate that members of the JAK/STAT proteins are present and modulated in vivo in the embryonic and postnatal brain, therefore supporting their role in the modulation of gene expression during the different stages of brain maturation.

Vitamin D metabolites activate the sphingomyelin pathway and induce death of glioblastoma cells

1 alpha, 25-dihydroxyvitamin D3 was previously shown to induce cell death in brain tumour cell lines when added to the medium at micromolar concentration. In this paper we show that Cholecalciferol, a poor ligand of the vitamin D receptor, also induces cell death of HU197 human glioblastoma cell line and early passages cultures derived from a recurrent human glioblastoma. This finding suggests that the effects of vitamin D metabolites on brain tumour cells are at least partially independent from the activation of the classic nuclear receptor pathway. Vitamin D metabolites have been shown to activate the sphingomyelin pathway inducing an increase in cellular ceramide concentration. We determined the levels of sphingomyelin ceramide and ganglioside GD3 in Hu197 cells after treatment with cholecalciferol. A significant increase in ceramide concentration and a proportional decrease in sphingomyelin was already present after 6 hours of cholecalciferol treatment when no morphological changes were visible in the cultures. Treatment with ceramides (N-acetylsphingosine or natural ceramide from bovine brain) of the same cells also induces cell death. Similarly, treatment of the same cells with bacterial Sphingomyelinase also results in cell death. The demonstration of an increase in intracellular ceramide after cholecalciferol treatment and the ability of ceramide to induce cell death suggest that the sphingomyelin pathway may be implicated in the effect of vitamin D metabolites on human glioblastoma cells. Inhibition of ceramide biosynthesis by fumonisin B1 treatment did not alter the dose response curve of HU197 cells to cholecalciferol. Insensitivity to fumonisin B1 together with a decrease in sphingomyelin content after cholecalciferol treatment indicate that activation of sphingomyelinase should be responsible for the increase in intracellular ceramide concentration.

Basal ganglia precursors found in aggregates following embryonic transplantation adopt a striatal phenotype in heterotopic locations

Transplantation of immature CNS-derived cells into the developing brain is a powerful approach to investigate the factors that regulate neuronal position and phenotype. CNS progenitor cells dissociated from the embryonic striatum and implanted into the brain of embryos of the same species generate cells that reaggregate to form easily recognizable structures that we previously called clusters and cells that disperse and integrate as single cells into the host brain. We sought to determine if the neurons in the clusters differentiate according to their final location or acquire a striatal phenotype in heterotopic positions. We transplanted dissociated cells from the E14 rat medial and lateral ganglionic eminences, either combined or in isolation, into the E16 embryonic rat brain. At all time points, we found clusters of BrdU- and DiI-labelled donor cells located in the forebrain and hindbrain, without any apparent preference for striatum. Immunocytochemical analyses revealed that cells in the clusters expressed DARPP-32 and ARPP-21, two antigens typically co-expressed in striatal medium-sized spiny neurons. In agreement with observations previously noted by several groups, isolated cells integrated into heterologous host areas do not express basal ganglia phenotypes. These data imply that immature striatal neuronal progenitors exert a community effect on each other that is permissive and/or instructive for development of a striatal phenotype in heterotopic locations.

Variations in the levels of the JAK/STAT and ShcA proteins in human brain tumors

BACKGROUND

Recent demonstrations that the JAK/STAT and ShcA signalling proteins are abundant in the developing CNS at the stage of maximal cell proliferation prompted us to determine whether these proteins were expressed in various human brain tumors.

MATERIALS AND METHODS

Using Western blot assay, we analyzed specimens from control peritumoral brain tissue, medulloblastomas, ependimomas, astrocytomas, anaplastic astrocytomas and glioblastomas.

RESULTS

Our analyses revealed that Jak1 and Stat3 were consistently more elevated in low grade gliomas (LG) (tumors characterized by a more pronounced glial phenotype) as compared to high grade gliomas (HG) (less differentiated glial tumors). The other STAT proteins were equally expressed, while Stat1 was slightly higher in LG gliomas. Among the other tumors analyzed, medulloblastoma contained the highest level of Jak1 and Stat3, while ependymoma showed elevated levels of ShcA proteins.

CONCLUSIONS

These differences may reflect differences in the biological characteristics of the various tumors and may provide insight for further mechanistic studies to investigate the importance of particular signal transduction pathways in CNS tumors.

Lineage specification of olfactory neural precursor cells depends on continuous cell interactions

We transplanted, as a single cell suspension, cells dissociated from the mature and immature olfactory epithelium of rats or TgR(ROSA26)26Sor mice expressing constitutively the LacZ gene into the developing brain (cerebellum, striatum, inferior colliculus, lateral ventricles) of E15 rat fetuses. Grafted cells or their descendants were still present in the central nervous system more than a month after transplantation. Transplanted cells either integrated as isolated cells or, during the first day after transplantation, reaggregated into clusters. Scattered cells, despite their placodal origin, differentiated into neuron or glial cells with a central phenotype. This was demonstrated by anatomical methods and selective amplification of cDNA encoding for neuronal specific transcripts (microtubule-associated protein 2 and middle-molecular-mass neurofilament protein) expressed by the engrafted cells. Cells in large clusters generated an epithelium containing mature olfactory neurons. Some of them were immunoreactive for the olfactory marker protein. Our findings show that cells dissociated from the developing and adult olfactory organs when transplanted into the rat fetal brain can either completely change their fate and differentiate according to their final position or generate an olfactory epithelium if they reaggregate into large clusters.

CNS-85 trial: a cooperative pediatric CNS tumor study--results of treatment of medulloblastoma patients

Between 1985 and 1989, 38 children with newly diagnosed medulloblastoma entered our therapeutic protocol. After surgery and postoperative staging assessments, patients were assigned to risk groups. Eleven with "standard-risk" (SR) tumors were treated with radiation therapy alone, while 27 with "high-risk" (HR) tumors received radiation therapy plus adjuvant chemotherapy with vincristine, methotrexate, VM-26, and 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU). After a minimum follow-up of 5 years (range 5-9 years) 21/38 children had developed a recurrence or progression of their disease and 19/38 patients had died. Five-year event-free survival rates and 5-year total survival rates for all 38 patients were 47.4% and 50% respectively. The event-free survival rates at 5 years for SR and HR patients separately were 27.3% and 55.6%, respectively. The corresponding 5-year total survival rates were 27.3% and 59.3%. The differences were not statistically significant. Univariate analysis showed age at diagnosis to be the most important prognostic factor. Infants aged 5 years or less had a significantly shorter event-free survival time than older patients (P = 0.00897). Similar effects were found when total survival time was considered. There were significant differences in outcome in patients receiving different doses of radiation, suggesting a dose-response relationship. A Cox stepwise multivariate analysis showed age at diagnosis as the only independent prognostic factor. Variables relating to treatment entered the model, suggesting that chemotherapy could play an important role in determining outcome.

Effects of vitamin D and retinoic acid on human glioblastoma cell lines

The biological significance of vitamin D receptors expressed by glioblastoma and other glial tumours is still unclear. In an effort to clarify this issue we studied the effects of increasing concentrations of 25-dihydroxyvitamin D3 and its metabolite 1 alpha,25-dihydroxyvitamin D3 on two human glioblastoma cell lines. Both substances were capable of inducing a significant (> 50%) reduction in growth of the two glioblastoma cell lines at dosages over 5 microM. When the HU 70 cell line was treated by increasing dilutions of 25-dihydroxyvitamin D3 combined with 1 microM all trans-retinoic acid, significant inhibition was apparent even after addition of 25-dihydroxyvitamin D3 in the nanomolar range. Reduction of growth index was mainly due to induced cell death. Our results provide in vitro evidence that vitamin D metabolites alone or in combination with retinoids may be potentially useful agents in the differentiation therapy of human malignant gliomas.

Cell death in the olfactory epithelium

In the nervous system of vertebrates the olfactory epithelium presents unique cytological characteristics. In the olfactory mucosa, olfactory neurons die and are replaced from undifferentiated neuroblasts over the entire life span of the animal. It remains unclear whether these neurons die as a result of a direct insult from the environment or in fulfillment of a physiological program of cell death. We have studied the distribution and the characteristics of cell death in the olfactory epithelium of normal, adult rats. The olfactory epithelium contains pycnotic bodies resembling those described for thymocytes undergoing terminal apoptotic changes. These appear at all levels in the epithelium, under both light and electron microscopes and can also be demonstrated after vital staining with acridine orange. Chromatin condensation into large blocks, often located at the nuclear periphery, is a morphological hallmark of the nuclei of mature olfactory neurons, which also present an increase in electron density of the cytoplasm. After non-radioactive in situ labeling of fragmented DNA, the nuclei of olfactory neurons are positive. Under the same reaction conditions (mild protease digestion), most of the nuclei of the supporting and basal cells are negative. In vivo incorporation of 5-bromouridine, a marker of RNA synthesis, is also lower in olfactory neurons than in basal and supporting cells. These findings suggest that olfactory neurons are committed very early to physiological cell death.

The establishment of intracellular symbiosis in an ancestor of cockroaches and termites

All cockroaches examined so far have been found to harbour a bacterial endosymbiont in specialized cells of the fat body, whereas Mastotermes darwiniensis is the only termite currently known to harbour an intracellular symbiont. The localization and mode of transmission of these bacteria are surprisingly similar, but so far no data have been published on their phylogenetic relationships. To address this issue, molecular sequence data were obtained from the genes encoding the small subunit ribosomal RNA of the M. darwiniensis endosymbiont, and compared with those obtained from endosymbionts of seven species of cockroaches. Molecular phylogenetic analysis unambiguously placed all these bacteria among the flavobacteria-bacteroides, indicating that the endosymbiont of M. darwiniensis is the sister group to the cockroach endosymbionts examined. Additionally, nucleotide divergence between the endosymbionts appears to be congruent with the palaeontological data on the hosts's evolution. These results support previous claims that the original infection occurred in an ancestor common to cockroaches and termites. A loss of endosymbionts should subsequently have occurred in all termite lineages, except that which gave rise to M. darwiniensis.

In vivo enhanced antitumor activity of carmustine [N,N'-bis(2-chloroethyl)-N-nitrosourea] by simvastatin

The effects of a combination of simvastatin, a cholesterol-lowering agent, and carmustine (BCNU; N,N'-bis(2-chloroethyl)-N-nitrosourea) on experimental C6 glioma were studied in vitro and in vivo. In vitro simvastatin and BCNU alone inhibited cell proliferation in a dose-dependent fashion. A subliminal concentration of simvastatin (0.1 microM) markedly and synergistically increased the BCNU toxicity to C6 glioma cells. The cytofluorimetric analysis of DNA from simvastatin-treated C6 glioma cells showed, besides the already described arrest in G1, an arrest/retardation in G2-M. Mitotic index from C6 cells incubated with simvastatin (10 microM) decreased by about 90%, indicating a specific C6 arrest/retardation in G2. The drug effects could be completely reversed by simvastatin withdrawal or mevalonate addition to the cultured cells. The combination of simvastatin and BCNU resulted predominantly from the profound retardation of cells in the G2-M compartment of the cell cycle. In vivo simvastatin (administered daily mixed with food) and BCNU (single i.p. injection), when given separately, caused a dose-dependent inhibition of labeling index in C6 glioma homografts (ID50, 61 mg/kg/day and 8.7 mg/kg, respectively). The combination of the lowest doses tested (simvastatin, 25 mg/kg/day and BCNU 0.3 mg/kg) resulted in a significant growth delay (compared to either drug alone) in C6 glioma (P < 0.05). There was no significant increase in toxicity as assessed by myelosuppression (WBC counts and bone marrow labeling index) and body weight. The results provide in vivo support for the combined use of simvastatin, a cholesterol-lowering agent, and BCNU in brain tumor treatment.

A short term analysis of the behaviour of conditionally immortalized neuronal progenitors and primary neuroepithelial cells implanted into the fetal rat brain

Conditionally immortalized (temperature-sensitive) striatal-derived neuronal progenitor cell lines and primary neuroepithelial cells were transplanted into the CNS of gestational day 15-16 rat fetuses using an 'in utero' surgical procedure. Each fetus received 2.5-3 x 10(4) donor cells previously labelled in vitro by incubation with 5-bromo-2'-deoxyuridine (BrdU). At 5 days following transplantation, 69% of the fetuses were still alive. Engrafted cells were detected by BrdU immunohistochemistry, and the appearance of the engrafted cells and the time course of Nestin and PCNA expression were measured at 6, 24, 64 h and 5 days after transplantation. The evolution of Large T-Antigen immunoreactivity in engrafted temperature-sensitive (ts) cells was also evaluated at the above time intervals. The results indicate that the majority of the implanted cells were aggregated into clusters 24 h after transplantation. These clusters were not visible at 6 h, when most of the cells were isolated. The clusters were located in both the ventricles and parenchyma. These findings were common to both ts cells and striatal primary neuroepithelial cells. At 64 h and 5 days, isolated cells associated with the germinal layer and scattered throughout the parenchyma were also found. In the clusters, Nestin expression decreased proportionally with time following transplantation. Furthermore, Large T-Antigen immunoreactivity disappeared from ts cells between 6 and 24 h after transplantation. Finally, measurements of the temporal evolution of PCNA expression within the clusters indicate a progressive reduction in the mitotic activity of the transplanted cells. The results demonstrate that striatal primary neuroepithelial cells and conditionally immortalized neuronal progenitors can survive, migrate and/or compartimentalize into clusters whilst changing their antigenic properties and ability to proliferate.

Flavobacteria as intracellular symbionts in cockroaches

Animal cells are the sole habitat for a variety of bacteria. Molecular sequence data have been used to position a number of these intracellular microorganisms in the overall scheme of eubacterial evolution. Most of them have been classified as proteobacteria or chlamydiae. Here we present molecular evidence placing an intracellular symbiont among the flavobacteria-bacteroides. This microorganism inhabits specialized cells in the cockroach fat body and has been described as a mutualistic endosymbiont of uncertain phylogenetic position. The small subunit ribosomal DNA of these bacteria was analysed after polymerase chain reaction amplification to investigate their phylogeny. The endosymbionts of five species of cockroaches were found to make up a coherent group with no close relatives within the eubacterial phylum defined by the flavobacteria. In addition, the relationships among the endosymbionts, as revealed by DNA sequence data, appeared to be congruent with the host taxonomic relationships. Based on the host fossil record, a tentative calibration of the nucleotide substitution rate for the cockroach flavobacteria gave results congruent with those obtained for the aphid endosymbiotic proteobacteria.

The expression of genes of the steroid-thyroid hormone receptor superfamily in central nervous system tumors

We studied the expression of ten genes (encoding the receptors for glucocorticoid, mineralocorticoid, progesterone, androgen, estrogen, thyroid, retinoid acid, vitamin D) belonging to the steroid-thyroid hormone receptor superfamily (STRS) in 12 neuroepithelial tumors, 12 meningiomas and 2 human glioblastoma cell lines. Our method, based on the polymerase chain reaction, allowed the simultaneous amplification of cDNAs of the STRS genes. On average, 7 STRS genes were simultaneously expressed in each sample. Our study indicates that many STRS gene are commonly co-expressed in human CNS tumors. The importance of our results for the ongoing and proposed hormonal treatment trials is discussed.

Proliferative effect of dexamethasone on a human glioblastoma cell line (HU 197) is mediated by glucocorticoid receptors

The relationship between Dexamethasone proliferative activity and the presence of glucocorticoid receptors was studied on a human glioblastoma cell line (HU 197). For this purpose, the 17 beta-Carboxamide steroid DXB, a glucocorticoid antagonist that competes with Dexamethasone for binding to the intracellular glucocorticoid receptor but does not trigger the glucocorticoid effect, was used. Concurrent treatments with Dexamethasone and DXB caused an inhibition of the proliferative effect obtained by Dexamethasone. The results obtained demonstrated that the Dexamethasone activity on cell proliferation is a specific receptor-mediated effect.

Vitamin D receptor expression in human brain tumors

Vitamin D receptor (VDR) has important effects not only on physiological processes related to Ca2+ metabolism but also on cell growth and differentiation. VDR is a member of the Steroid-Thyroid Receptors Superfamily (STRS). Work in our and other laboratories has shown that several other members of the STRS (androgen, estrogen, glucocorticoid, and progesterone receptors) are present in astrocytomas and glioblastomas. We now report the finding of VDR-like mRNA in human anaplastic astrocytomas and glioblastomas. VDR mRNA levels, as determined by a method, developed in our laboratory, based on the polymerase chain reaction, are significantly higher in glioblastomas compared to both low and high grade astrocytomas. We discuss the biological and clinical implications of our results.

Characteristics and biological role of steroid hormone receptors in neuroepithelial tumors

Tissue samples from 57 patients with neuroepithelial tumors (25 glioblastomas, 18 anaplastic astrocytomas, and 14 astrocytomas) were analyzed in order to evaluate the presence of estrogen, progesterone, glucocorticoid, and androgen receptors. Glucocorticoid- and androgen-specific binding proteins were present in 38.6% and 21.6% of the cases, respectively. Only a few tumors showed estrogen or progesterone receptors. A correlation was found between grade of anaplasia, patient's sex and age, and presence of glucocorticoid and androgen receptors. The biological role of these two receptors was investigated in 10 primary cell cultures derived from neuroepithelial tumors. For this purpose, dexamethasone and testosterone were added to culture medium at different concentrations (from 50 to 0.016 micrograms/ml). A significant stimulation of the cell growth was observed in four of five glucocorticoid receptor-positive cultures when dexamethasone in doses ranging from 2 to 0.016 microgram/ml was added to the culture. No modulation of the growth was observed in glucocorticoid receptor-negative cultures at the same doses. Higher dexamethasone doses induced a significant decrease of the growth index independently from the glucocorticoid receptor status. All of the cultures tested for testosterone activity were negative for androgen receptors. This hormone induced an inhibition of the growth index at doses ranging from 50 to 0.4 micrograms/ml. The data suggest that neuroepithelial tumors contain specific glucocorticoid and androgen binding proteins. Glucocorticoid receptors modulate the growth of cultured neuroepithelial tumors in the presence of different concentrations of dexamethasone.

Cell-kinetic characteristics of human brain tumors

The proliferative potential of human brain tumors was investigated, in vivo, using bromodeoxyuridine (BUDR) incorporation and flow cytometry (FCM). Patients with a variety of human brain tumors were preoperatively injected with 250 mg of BUDR intravenously. The cell cycle parameters of most of the specimen were measured within 24 h of sampling. The results show that this method is very practical, fast, and feasible for determining the cell-kinetic parameters of human brain tumors. In this study important kinetic parameters such as the duration of S-phase and the potential doubling time of each tumor were calculated in some samples. Our results show a significant difference in labelling index between meningiomas and gliomas. No difference between benign and anaplastic meningiomas was demonstrated in this limited number of cases. The correlation between the labelling index and the clinical and radiological follow-up of each patient should make the assessment of the prognostic significance of the kinetic evaluation, possible. This method could be a useful aid in the selection of new treatment schedules.

The pattern of cell death in fushi tarazu, a segmentation gene of Drosophila

The pair-rule mutant, fushi tarazu, causes deletion of alternate metameres. Here we show that there is cell death in the mutant which begins at the completion of germ band extension. We map the dying cells in the epidermis; they occur scattered all over those regions that, in the wild type, would form the even-numbered parasegments and are also found in posterior parts of the odd-numbered parasegments. In the affected zones, dying and dividing cells are intermingled; we suggest that cells from these zones may still give descendents that contribute to the larval cuticle. Cell death is not limited to those cells that would normally express ftz+, suggesting that it is some indirect consequence of the abnormal situation in the mutant embryo.

Nerve terminal remodeling visualized in living mice by repeated examination of the same neuron

The distribution of presynaptic endings on the surfaces of autonomic ganglion cells was mapped in living mice after intravenous administration of a styryl pyridinium dye. The staining and imaging techniques did not appear to damage the ganglion cells, or the synapses on them; these procedures could therefore be repeated after an arbitrary period. Observations of the same neurons at intervals of up to 3 weeks indicate that the pattern of preganglionic terminals on many of these nerve cells gradually changes.

Single olfactory organ associated with prosencephalic malformation and cyclopia in a Xenopus laevis tadpole

A cyclops Xenopus laevis tadpole with a single olfactory organ is described. At a stage comparable to 48, the telencephalon was severely atrophic and only the region where the olfactory fibres terminated appeared to have the cytoarchitecture of the olfactory bulb. In this animal the central nervous system (CNS) appeared normally developed only posterior to the preoptic area. The hypothesis of a diencephalic origin of the region where the olfactory fibres terminated is discussed in the light of our previous results of olfactory placode transplantation. By analogy between this case and other malformations (cyclopia, holoprosencephaly) in higher vertebrates and humans, the need is emphasized for a more precise anatomical description of the olfactory input in related malformations.

Fluorescent probes that stain living nerve terminals

We have evaluated the efficacy of 18 cationic mitochondrial dyes that, as a class, show some ability to stain living nerve terminals. Several of these agents provide excellent staining of neuromuscular junctions in a wide range of species. More detailed studies of the most effective of these dyes--4-(4-diethylaminostyryl)-N-methylpyridinium iodide (4-Di-2-ASP)--indicate that it has no lasting effect on the structure or function of motor nerve terminals. As demonstrated in the accompanying paper (Lichtman et al., 1987; see also Lichtman et al., 1986), 4-Di-2-ASP can therefore be used to follow the configuration of identified motor terminals over arbitrarily long intervals.

Visualization of neuromuscular junctions over periods of several months in living mice

Identified neuromuscular junctions were followed in the sternomastoid muscle of living mice for several months by repeated staining with the fluorescent dye 4-(4-diethylaminostyryl)-N-methylpyridinium iodide (4-Di-2-ASP; Magrassi et al., 1987). Overall terminal growth occurred at many endplates; however, the branching pattern of presynaptic arbors was largely unchanged, even after several months. The absence of significant remodeling over time was not a result of dye-staining, since sprouting was readily induced at residual motor endings by partial denervation. We conclude that--apart from overall growth--most neuromuscular junctions in the adult mouse are stable over intervals that represent a significant fraction of the animal's lifetime.

Interaction of the transplanted olfactory placode with the optic stalk and the diencephalon in Xenopus laevis embryos

The effect of olfactory placode transplantation on the differentiation of the optic vesicle and stalk has been studied in Xenopus laevis embryos. Host embryos (stages 23-24) received the transplant of two olfactory placodes from same-stage donors in place of a partially or totally removed optic vesicle. All tadpoles were sacrificed at stages 47-50. The host tadpoles were subdivided in three groups according to the amount of optic vesicle removed. In the first group all of the optic vesicle was removed. At sacrifice a lobar mass of nervous tissue, continuous with and protruding from the diencephalic wall, was penetrated by the olfactory nerves from the transplanted placodes and a well-defined glomerular layer was present at the entrance zone of the olfactory nerves. The lobar protrusion contained a normal ventricular cavity, connected by a foramen to the third ventricle. The ventricle was lined by a mitotically active ependymal layer. In the second group the host embryos were deprived of two-thirds of the optic vesicle. In these animals we observed the development of a round mass of nervous tissue connected by a peduncle to the diencephalic wall. A ventricle lined by ependyma was present in the formation; however, the cavity was not continuous with the third ventricle. Olfactory nerves from the transplanted placodes penetrated the rostral portion of the nervous mass and formed a distinct glomerular layer. In the third group of embryos only one-third of the optic vesicle was removed. These animals developed irregularly shaped structures where ocular tissue and nervous tissue coexisted. The termination of the supranumerary olfactory nerves and the glomerular layer were restricted to the non-ocular nervous tissue. The interpretation of the histogenetic phenomena determining the protrusions is difficult and further studies are needed. It seems highly probable, however, that the fate of such determined structures as the optic peduncle and vesicle can be influenced by the olfactory input, supporting the hypothesis that the ectopically directed olfactory fibres interfere with the differentiation of the optic structures.

Morphological characterization of lymphoid cells conjugates with scattered tumor target cells in organ imprints of Yoshida ascites bearing rats

The authors analysed morphologically the ability of host effector cells to bind disseminated tumor target cells (pre-lysis) in vivo. Scattered tumor cells are morphologically visible stained with May Grünwald-Giemsa in the lung, liver, kidney, and spleen imprints of Yoshida ascites tumor bearing rats. Lymphoid cells can be seen binding disseminated tumor target cells in organs but not in the peritoneal cavity. This model may provide a useful technique for morphological studies on the in vivo conjugation capacity of host effector cells against tumor target cells.

Intraperitoneal transplantation of Yoshida ascites hepatoma cells after fine needle aspiration from tumor bearing rats organs

The authors tested the ability of scattered tumor cells to re-form a tumor in vivo. Disseminated tumor cells are morphologically visible stained with May-Grünwald Giemsa in the lung, liver, kidney, and spleen of Yoshida ascites tumor bearing rats. Free tumor cells can easily be fine needle aspirated from those organs and injected in syngeneic Wistar rats. All the host rats show ascites tumor take after intraperitoneal transplantation of each aspirated sample. This biological model might be useful to study in vivo a wide range of properties of neoplastic and non-neoplastic host cells.

Kinetics of the spread of the Yoshida ascites hepatoma cancer cells through various organs of the rat

In the present paper the attempt is pursued to provide a self-consistent interpretation for the quantitative measurements of the amount of neoplastic cells found at different anatomic sites and at various times after intraperitoneal injection. The model, employing a system of 8 linear differential equations with constant coefficients, can be fitted by means of a special program for a small processing system equipped with an 8-bit microprocessor and 48 KB of central memory.

[Preliminary findings on tumor cells in various organs of rats after transplantation of Yoshida hepatoma ascites cells]

In previous papers the techniques for the study of the migration pattern of tumor cells through the host tissues were described. In the present communication studies utilizing Yoshida ascitic tumor cells are referred. Neoplastic cells morphologically identified were counted in several organs at various times of the development of the tumor transplantation. This method appears to provide interesting indications about the dynamics of the neoplastic spread through the tissues.