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At least 487 records · Page 27Linked to original sources
PubMed1996

Differential regulation of small heat-shock genes in plants: analysis of a water-stress-inducible and developmentally activated sunflower promoter.

We have isolated two sunflower genes, Ha hsp18.6 G2 and Ha hsp17.7 G4, that encode small heat shock proteins (sHSPs). RNAse A protection experiments, carried out with RNA probes transcribed from each gene and hybridized to sunflower total RNA, allowed us to distinguish their mRNA accumulation patterns. In sunflower, Ha hsp17.7 G4 mRNAs accumulated during zygotic embryogenesis at 25 degrees C. In vegetative tissues, these mRNAs accumulated in response to either heat shock (42 degrees C), abscisic acid (ABA), or mild water stress treatments. In all cases, the mRNAs were transcribed from the same initiation site. In contrast, Ha hsp 18.6 G2 mRNAs accumulated only in response to heat-shock. This result demonstrates differential regulation of these two sHSP genes. The complex regulation depicted by the Ha hsp 17.7 G4 promoter has been further analyzed in transgenic tobacco, using G4::GUS translational fusions. Developmental induction of Ha hsp 17.7 G4 during zygotic embryogenesis was faithfully reproduced in the transgenic plants. 5'-distal sequences (between -1132 and -395) were required to confer a preferential spatial expression of GUS activity in the cotyledons. More proximal sequences (from -83 to +163) conferred to the chimeric genes most of the developmental regulation, and the responses to ABA and heat shock characteristic of the Ha hsp17.7 G4 promoter. The water stress response of this gene was not reproduced in transgenic tobacco and, thus, could be uncoupled from its regulation during embryogenesis.

Abscisic Acid↗
PubMed1994

Expression of sunflower low-molecular-weight heat-shock proteins during embryogenesis and persistence after germination: localization and possible functional implications.

We isolated and sequenced Ha hsp17.9, a DNA complementary (cDNA) of dry-seed stored mRNA that encodes a low-molecular-weight heat-shock protein (LMW HSP). Sequence analysis identified Ha hsp17.9, and the previously reported Ha hsp17.6, as cDNAs encoding proteins (HSP17.6 and HSP17.9) which belong to different families of cytoplasmic LMW HSPs. Using specific antibodies we observed differential expression of both proteins during zygotic embryogenesis under controlled environment, and a remarkable persistence of these LMW HSPs during germination. Immuno-blot analysis of HSP17.9 proteins in two-dimensional gels revealed that the polypeptides expressed in embryos were indistinguishable from LMW HSPs expressed in vegetative tissues in response to water deficit; but they appeared different from homologous proteins expressed in response to thermal-stress. Tissue-print immunolocalization experiments showed that HSP17.9 and HSP17.6 were homogeneously distributed in every tissue of desiccation-tolerant dry seeds and young seedlings under non-stress conditions. These results demonstrate developmental regulation of specific, cytoplasmic, plant LMW HSPs, suggesting also their involvement in water-stress tolerance.

Adaptation, Biological↗
PubMed1991

Gamma-interferon induces differential expression of HLA-DR, -DP and -DQ in human ciliary epithelial cells.

The antigen-specific activation of T-helper lymphocytes is dependent on the presentation of antigen in context with the gene products of the major histocompatibility complex class II (MHC II). Aberrant expression of MHC II on the ciliary epithelium has been observed in uveitic eyes which may enable these cells to specifically interact with lymphocytes and may play a role in ocular autoimmunity. Human MHC II consists of three subclasses termed HLA-DR, -DP and -DQ, which seem to be differentially regulated and may have different functions. The present study was initiated to investigate the dynamics of the differential MHC II expression on cultured human non-pigmented ciliary epithelial cells (NPE cells) in response to gamma-interferon (gamma-IFN) by means of immunohistochemistry. NPE cells grown in control tissue-culture medium did not express MHC class II. HLA-DR and -DP could be induced by incubation with 100 mu/ml gamma-IFN for 3 days. HLA-DQ was expressed only weakly and at higher doses of gamma-IFN (greater than or equal to 500 mu/ml) and longer incubation periods (greater than or equal to 5 days). After removal of the gamma-IFN stimulus, all three MHC II subclasses persisted for several days. The differential expression of HLA-DR and -DP as compared with HLA-DQ in response to gamma-IFN in the ciliary epithelium is similar to observations in other non-lymphoid ocular cells but appears to be different from the regulation of MHC II expression on lymphoid cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1991

Mammalian ciliary-body epithelial cells in culture produce transforming growth factor-beta.

Transforming growth factor-beta (TGF-beta) has recently been found in the aqueous humor. The present study was initiated to test whether the ciliary-body epithelium, the site of aqueous humor formation, is capable of producing TGF-beta. Human, rat and bovine ciliary epithelial cells were grown in tissue culture and their supernatants were tested for TGF-beta using a bioassay. After acid activation of the samples, TGF-beta activity was found in the supernatants of all three mammalian ciliary epithelial cells. Most of this activity could be blocked by a neutralizing antibody against TGF-beta type 2. Native supernatants did not contain detectable TGF-beta activity. Thus, the ciliary epithelium is capable of producing the inactive form of TGF-beta (mainly type 2) and may be a source of TGF-beta in the aqueous humor.

Animals↗
PubMed1983

Ciliary epithelia of the mammalian eye in cultured explants.

The ultrastructural characteristics of ciliary epithelium from bovine, pigmented rabbit, and fetal albino rabbit were studied in cultured explants. The tips of ciliary processes were cultured in plastic dishes with Dulbecco Modified Eagle Medium (DMEM) containing 5% fetal bovine serum. More than half of the explants adhered to the plastic culture dish, and epithelial cells spread as monolayers within a few days. Initially the explant contains two layers, the outer (nonpigmented cells) and the inner (pigmented cells). Later the explant exhibits three layers: 1) outermost lightly pigmented flattened cells, 2) an outer layer of non-pigmented cells, and 3) an inner layer of densely pigmented cuboidal cells. The cells of the outermost layer are continuous with the cells of the inner layer. A narrow space lies between the outermost layer and the outer layer. The columnar cells in the outer layer contain well developed organelles but no pigment granules; they possess a basement membrane, lateral interdigitations, and junctional complexes near their apices. Numerous focal junctions and some ciliary channel-like structures were detected between the columnar cells of the outer layer and the cuboidal cells of the inner layer. The cuboidal cells of the inner layer are filled with pigment granules. These observations suggest that the columnar cells of the outer layer are nonpigmented epithelium, the cuboidal cells of the inner layer are pigmented epithelium, and the flattened cells in the outermost layer are derived from pigmented epithelium.

Animals↗
PubMed1994

Neurocytoma of spinal cord.

We report a case of spinal cord neurocytoma in a 67-year-old man who had experienced a progressive numbness of the left foot during the previous 4 years. Magnetic resonance imaging showed a well-defined intramedullary tumor located at the T10-T11 level. The pathological examination revealed histological characteristics described in neurocytomas. The tumor cells showed a uniform small nucleus and clear or slightly eosinophilic cytoplasm with frequent perinuclear halos, resembling the picture of oligodendroglioma. Some tumor cells exhibited mature ganglion cell appearance. Electron microscopy showed cells with microtubules and dense-core vesicles in their cytoplasm and cytoplasmic process. Immunohistochemically, the majority of tumor cells expressed synaptophysin and neuron-specific enolase. We conclude that this tumor is an exceptional case of neurocytoma located in the spinal cord, and consider that the term neurocytoma can be applied to tumors with neuronal differentiation intermediate between neuroblastoma and ganglioneuroma, even if arising in CNS outside of the intracranial ventricular system.

Aged↗
PubMed1995

Feasibility of first-pass radionuclide angiocardiography with a 10-mCi technetium bolus using a single-crystal digital gamma camera: implications for technetium-sestamibi single-day protocols.

To test the feasibility of rest first-pass radionuclide angiocardiography (FPRNA) using a 370-MBq (10-mCi) bolus and a single-crystal gamma camera, 40 patients underwent both FPRNA and equilibrium radionuclide angiocardiography (ERNA). Ejection fraction (EF) and regional wall motion (RWM) were assessed by three observers. The interobserver reproducibility was good: the intraclass correlation coefficient was 0.97 for both techniques. The correlation coefficient between FPRNA and ERNA EFs ranged between 0.90 and 0.92. FPRN EFs were significantly higher (P < 0.003) by less than 5 percentage points, this difference having no clinical implications for patient classification. The study provides arguments as to why this difference may be explained self-attenuation rather than counts statistics problems. Both techniques were concordant for RWM analysis. We conclude that FPRNA with 10 mCi is a reliable tool to assess rest left ventricular function, which makes it possible to perform simultaneously myocardial perfusion and function assessment in a single-day protocol using a single-crystal gamma camera.

Feasibility Studies↗
PubMed1992

Delayed transplantation of foetal cerebral tissue into injured spinal cord of adult rats.

Delayed transplantation of foetal cerebral tissue into injured spinal cord of adult rats was performed for the purpose of evaluating the usefulness of the procedure for reconstructing the spinal cord and providing motor recovery. Transplanted tissue showed a survival rate greater than 80% and integration with the host tissue. Nerve fibers of the host surrounded the transplanted tissue, penetrating it. Foetal cerebral neurons matured into recipient spinal cord, but they were not organized in layers. The experience obtained suggests that delayed transplantation of foetal cerebral tissue into contused spinal cord is useful in morphological spinal cord reconstruction. Nevertheless, at least during the first two months after transplantation, clinical assessment of motor recovery showed no differences between transplanted and nontransplanted rats.

Animals↗
PubMed1987

Intrathecal injection of autologous leucocytes in glioblastoma: circulatory dynamics within the subarachnoid space and clinical results.

In part I of this report, the CSF circulatory dynamics of autologous leucocytes labelled with indium-111 and injected in the subarachnoid space, in patients operated on for glioblastoma, were studied. In the Part II, a series of 11 patients with recurrent glioblastoma was studied for evaluating the efficacy of intrathecal injection of autologous leucocytes. Six patients previously had radiotherapy. The results in Part I show that after intrathecal injection of autologous leucocytes, these cells follow throughout the subarachnoid space and pass to the systemic blood circulation, showing no evidence of colonization of the tumour or deposit in the tumoural region. The mean survival of the patients studied in Part II was 8 months. Those six patients who received radiotherapy had a mean survival of 11.4 months, and those five who received only intrathecal injection of autologous leucocytes after surgery, had a mean survival of 4 months. This results seem to demonstrate that immunotherapy, as used in this study, is ineffective in patients with glioblastoma.

Adult↗
PubMed1989

Intratumoural injection of autologous lymphocytes plus human lymphoblastoid interferon for the treatment of glioblastoma.

Preliminary experience with a clinical trial of immunotherapy for glioblastoma, by means of intratumoural injection of autologous lymphocytes (AL) mixed with low doses of human lymphoblastoid interferon (HLI) is presented. In two of twelve patients, a transient reduction of tumoural volume was obtained. Morphological studies showed that injected lymphocytes remain within the tumour, and suggest tumoural lysis due to activity of natural killer (NK) cells. Clinically no significant prolongation of survival time could be achieved and, as in other series, patients with additional radiation therapy survived longer. But the morphological findings suggest that immunotherapy carrying NK-cells to contact with tumoural cells might be useful in some patients with glioblastoma. Actually no explanation can be given why only two of our cases responded positively. Regarding the otherwise poor prognosis it seems justified to continue these studies.

Adult↗
PubMed1996

Gangliosides modulate the growth rate and cell phenotype of a murine primitive neuro-ectodermal tumour.

Intratumoural administration of gangliosides (GSD) into a murine primitive neuro-ectodermal tumour, growing in the epicranial subcutaneous tissue of syngenic rats, results in a decrease in the tumour growth rate and causes a more differentiated phenotype of tumour cell, with immunohistochemical expression of neuronal markers. These findings suggest that the potential usefulness of intralesional administration of GSD for the control of tumours of primitive neuro-epithelial character could be considered.

Animals↗
PubMed1994

Experimental induction of primitive neuro-ectodermal tumours in rats: a re-appraisement of the ENU-model of neurocarcinogenesis.

A series of 122 experimental brain tumours, induced in the Wistar rat by means of prenatal exposition to ethyl-nitrosourea, were studied with histological, immunohistochemical and ultrastructural techniques. Although with conventional histological techniques, most of the induced tumours showed morphological features suggesting their classification as malignant schwannomas or oligodendroglioma-like neoplasms, their study by means of immunohistochemistry and electron microscopy suggested that they are, in fact, primitive neuroectodermal tumours, with a tendency toward neuronal differentiation. This finding obliges us to re-appraise the ethyl-nitrosourea model of neurocarcinogenesis and to consider its possible usefulness for the experimental study of therapeutic approaches with potential applications in human neuro-ectodermal neoplasms.

Animals↗
PubMed1990

Immunohistochemical study of IOT-10 natural killer cells in brain metastases.

The presence of NK-cells in a series of 40 metastatic brain tumours has been studied by means of the monoclonal antibody IOT-10. There appeared IOT-10 NK-cells in all tumours studied, but in most cases these cells represented less than 10% of the tumour infiltrating lymphocytes (TIL). In the present series, the obtained data suggest that the number of NK-cells in brain metastases can be influenced by other factors than the mere quantity of TIL.

Adenocarcinoma↗
PubMed1983

The influence of large decompressive craniectomy on the outcome of surgical treatment in spontaneous intracerebral haematomas.

The outcome of a series of 73 patients with spontaneous intraparenchymatous haematomas treated by surgical evacuation of the clot and decompressive craniectomy has been described. Comparing postoperative mortality of this series with another series of patients (54 cases) treated only with surgical removal of the clot without decompressive craniectomy a statistically significant improvement in the mortality rate after craniectomy could be observed in acute cases demanding surgical intervention for preservation of life in the first 24 hours. If signs of brain-stem suffering appear surgical mortality increases proportionally to the duration of this symptomatology. In these cases surgery, if it is to be useful, has to be performed as soon as possible. The morbidity of the surviving patients is not greater in this series with decompressive craniectomy than in series without decompression.

Adolescent↗