Coats' response in Leber's congenital amaurosis.
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Abnormalities, Multiple↗
Biomedical subjects
A Caputo
Publications and source records attributed to A Caputo.
Myxoma virus Serp2 is a weak inhibitor of granzyme B and interleukin-1beta-converting enzyme in vitro and unlike CrmA cannot block apoptosis in cowpox virus-infected cells.
The Serp2 protein encoded by the leporipoxvirus myxoma virus is essential for full virulence (F. Messud-Petit, J. Gelfi, M. Delverdier, M. F. Amardeilh, R. Py, G. Sutter, and S. Bertagnoli, J. Virol. 72:7830-7839, 1998) and, like crmA of cowpox virus (CPV), is reported to inhibit the interleukin-1beta-converting enzyme (ICE, caspase-1) (F. Petit, S. Bertagnoli, J. Gelfi, F. Fassy, C. Boucraut-Baralon, and A. Milon, J. Virol. 70:5860-5866, 1996). Serp2 and CrmA both contain Asp at the P1 position within the serpin reactive site loop and yet are only 35% identical overall. Serp2 protein was cleaved by ICE but, unlike CrmA, did not form a stable complex with ICE that was detectable by native gel electrophoresis. Attempts to covalently cross-link ICE-serpin inhibitory complexes were successful with CrmA, but no complex between ICE and Serp2 was visible after cross-linking. Purified His10-tagged Serp2 protein was a relatively poor inhibitor of ICE, with a Ki of 80 nM compared to 4 pM for CrmA. Serp2 protein resembled CrmA in that a stable complex with the serine proteinase granzyme B was detectable after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. However, Serp2 was less effective at inhibiting granzyme B activity (Ki = 420 nM) than CrmA (Ki = 100 nM). Finally, Serp2 was tested for the ability to replace CrmA and inhibit apoptosis in LLC-PK1 cells infected with a CPV recombinant deleted for CrmA but expressing Serp2. Unlike wild-type-CPV-infected cells, apoptosis was readily observed in cells infected with the recombinant virus, as indicated by the induction of both nuclear fragmentation and caspase-mediated cleavage of DEVD-AMC [acetyl-Asp-Glu-Val-Asp-(amino-4-methyl coumarin)]. These results indicate that Serp2 is unable to functionally substitute for CrmA within the context of CPV and that the inhibition spectra for Serp2 and CrmA are distinct.
Amino Acid Sequence↗
Characterization of the effects of two polysulfonated distamycin A derivatives, PNU145156E and PNU153429, on HIV type 1 Tat protein.
We examined whether two sulfonated distamycin A derivatives, PNU145156E and PNU153529, inhibit the trans-activating and angiogenic effects of HIV-1 Tat protein. The study was carried out by analyzing the activity of the two drugs on: (1) extracellular and intracellular Tat protein, introduced into HL3T1 cells containing an integrated HIV-1 LTR/CAT plasmid; (2) binding of Tat to 3H-labeled heparin and to 14C-labeled PNU145156E; and (3) the angiogenic response induced in vivo by culture medium conditioned by T53c14 cells, which release extracellular Tat. PNU145156E and PNU153429 interacted with extracellular Tat in the culture medium and physically bound the Tat protein, most likely sequestering it in the extracellular space. As a consequence, the two drugs inhibited trans-activation of the HIV-1 LTR on addition of the free Tat protein to HL3T1 cells. However, the two compounds inhibited the activity of intracellular Tat when they were introduced into the cells by lipofection. In vivo experiments showed that the two drugs blocked the neoangiogenesis induced by Tat released in the conditioned medium of T53c14 cells. Owing to the critical role of intracellular and extracellular Tat in HIV-1 replication, these drugs show promise as a means to control the progression of HIV-1 infection as well as the neoplastic and angiogenic effects induced by Tat in the course of AIDS.
Animals↗
Epithalamus calcifications in schizophrenia.
We evaluated the prevalence and the size of epithalamus calcifications (EC) and choroid plexus calcifications (CPC) on computed tomography (CT) scans in a group of 64 schizophrenic patients and in a group of 31 healthy controls. The associations between cerebral calcifications, demographic variables, and other brain morphological characteristics (particularly cerebral ventricular size and cortical atrophy) in both, patients and controls, were also considered. A significant increase in size of the epithalamic-region calcifications in schizophrenic patients was found, whereas there was no evidence of increase in both, dimension and prevalence, of choroid plexus calcification. Such dimensional increase was unrelated to the duration of illness and therefore did not seem to be iatrogenic or secondary to the disease. A correlation was found between epithalamus calcifications and cortical atrophy and third-ventricle enlargement, suggesting that calcifications of this cerebral region may be associated with lesions of third-periventricular areas and of circuitries hypothesized to be involved in the pathophysiology of schizophrenia.
Adolescent↗
Non-selective impairment of Wisconsin Card Sorting Test performance in patients with schizophrenia.
Sixty-two schizophrenic patients and 26 healthy volunteers were administered the Wisconsin Card Sorting Test (WCST) a task putatively specific for frontal functions and the Wechsler Adult Intelligence Scale (WAIS). The purpose of this study was to evaluate the presence of specific frontal lobe deficits in the course of schizophrenia and the capacity of these tasks to discriminate between patients and controls. Schizophrenic patients showed a poorer performance than control subjects in both tests. No evidence emerged to support a higher discriminant power for the WCST in identifying schizophrenic subjects from healthy controls compared with the WAIS. Our data suggest that the deficit in WCST performance is not selective, but rather part of a more generalized neuropsychological impairment in schizophrenic patients.
Adult↗
Upregulation of c-Fos in activated T lymphoid and monocytic cells by human immunodeficiency virus-1 Tat protein.
The regulatory Tat protein of the human immunodeficiency virus type-1 (HIV-1) is essential for viral replication and also shows pleiotropic activities on various cell functions. To get further insights into the molecular mechanisms underlying the biological activity of Tat, we investigated the effect of endogenous and exogenous Tat protein on c-fos gene expression in T lymphoblastoid (Jurkat) and monocytic (U937) cell lines, as well as in primary peripheral blood mononuclear cells (PBMC). Transient cotransfection of tat cDNA in sense orientation (tat/S), together with a plasmid containing the c-fos promoter (FC3, from -711 to +42) in front of the bacterial chloramphenicol acetyltransferase (CAT) gene significantly enhanced CAT activity in Jurkat cells activated by the addition of 15% fetal calf serum (FCS) or 5 micrograms/mL phytohemagglutinin plus 10(-7) mol/L phorbol myristate acetate (PMA) and U937 cells activated by 15% FCS or 10(-7) mol/L PMA. This effect was specifically due to Tat, since Jurkat and U937 cells cotransfected either with tat cDNA in antisense orientation (tat/AS), tat carrying a mutation in the aminoacid cys22-gly22 (tat 22/S) or with the backbone vector alone (pRPneo-SL3) did not show any significant difference in c-fos promoter activity as compared to cells transfected with FC3 plasmid alone. By using deletion mutants of the c-fos promoter, we found that the minimal DNA sequence required for Tat activity was located between nucleotides -404/-220 and that the serum responsive element (SRE, -317/-288), present within this region, was still responsive to Tat. A single point mutation in the SRE completely abrogated the responsiveness to tat/S. Exogenous recombinant Tat protein was also able to upregulate c-fos promoter activity in serum-activated Jurkat and U937 cells, as well as endogenous c-fos mRNA expression and c-Fos protein synthesis in both serum-activated cell lines and primary PBMC. c-Fos protein was shown essential for an optimal transactivation of the HIV-1 long terminal repeat (LTR) by Tat: incubation of Jurkat cells with antisense, but not sense, c-fos oligonucleotides significantly reduced either the Tat-enhanced expression of an LTR-CAT reporter construct or the levels of gag p24 in the culture supernatants of Jurkat cells and PBMC acutely infected with HIV-1. Our data suggest that the c-fos upregulation mediated by Tat might play a significant role in the control of viral gene transactivation.
Gene Expression Regulation, Neoplastic↗
Osseointegration enhanced by chemical etching of the titanium surface. A torque removal study in the rabbit.
Roughened implant surfaces are thought to enhance osseointegration. Torque removal forces have been used as a biomechanical measure of anchorage or osseointegration in which the greater forces required to remove implants may be interpreted as an increase in the strength of osseointegration. The purpose of this study was to compare the torque resistance to removal of screw shaped titanium implants having an acid etched (HC1/H2SO4) surface (Osseotite) with implants having a machined surface. Two custom screw shaped implants, 1 acid etched and the other machined, were placed into the distal femurs of 10 adult New Zealand White rabbits. These implants were 3.25 mm in diameter x 4.00 mm in length without holes, grooves or slots to resist rotation. Following a 2 month healing period, the implants were removed under reverse torque rotation with a digital torque measuring device. Two implants with the machined surface preparation failed to achieve osseointegration. All other implants were found to be anchored to bone. Resistance to torque removal was found to be 4 x greater for the implants with the acid etched surface as compared to the implants with the machined surface. The mean torque values were 20.50 +/- 6.59 N cm and 4.95 +/- 1.61 N cm for the acid etched and machined surfaces respectively. The results of this study suggest that chemical etching of the titanium implant surface significantly increases the strength of osseointegration as determined by resistance to reverse torque rotation.
Acid Etching, Dental↗
Studies on the effect of the combined expression of anti-tat and anti-rev genes on HIV-1 replication.
A series of retroviral vectors with potential anti-tat and antirev activity was developed. Vectors containing a tat transdominant negative mutant (tat22/37) and an RRE decoy in different positions, directed by the same promoter or by different promoters, were generated. Retroviral vectors containing tat22/37 and the RevM10 transdominant negative mutant were also constructed. Jurkat cells were transduced with the recombinant retroviruses to produce monoclonal and polyclonal cultures. In these cell lines the recombinant proviruses were correctly integrated and expression of the inserted genes was detected by Northern blot or RT-PCR analysis. However, infection of these cell lines with HIV-1 showed that none of these recombinant constructs inhibited virus replication at a high multiplicity of infection (MOI). At a low MOI, two cell clones containing tat22/37 and the RRE decoy in 3' position showed a long lasting protection against virus replication, in comparison to control cultures expressing tat22/37 or RRE alone. Combination of tat and rev mutants was ineffective in inhibiting HIV-1 replication at both low and high MOIs. At a low MOI, HIV-1 replication was efficiently blocked in two cell clones expressing the RevM10 mutant alone. These results show a synergic effect of anti-tat and anti-rev molecules when the RRE sequence is cloned 3' to tat22/37, suggesting the possibility of using this vector design to control HIV-1 replication.
DNA, Recombinant↗
Inhibition of HIV-1 replication by a Tat transdominant negative mutant in human peripheral blood lymphocytes from healthy donors and HIV-1-infected patients.
It was previously shown that a tat mutant (tat22) where cysteine 22 is substituted by glycine behaves as a transdominant negative mutant in Jurkat T cells lytically or latently infected by HIV-1. In this study we demonstrate that tat22 controls HIV-1 replication in primary cells. This effect was observed both after in vitro infection of peripheral blood mononuclear cells (PBMCs) from normal donors and after reactivation of the latent infection in PBMCs from seropositive patients. The antiviral effect of tat22 was limited to conditions of low virus production. The use of tat22 may be promising for a gene therapy approach to AIDS during the asymptomatic phase of the disease allowing control of virus replication in infected cells and inhibition of virus spread to uninfected cells.
Gene Products, tat↗
Comparing the accuracy of reversible hydrocolloid and elastomeric impression materials.
This in vitro investigation evaluated the accuracy of reversible hydrocolloid, vinyl polysiloxane and polyether elastic impression materials used in conjunction with two die stones. The authors made impressions in an experimental environment that approximated clinical conditions in regard to temperature and moisture. Analysis of variance and t-tests were used to compare corresponding measurements on experimental casts made from the various impression materials.
Alginates↗
A physical interaction between the cell death protein Fas and the tyrosine kinase p59fynT.
The Fas antigen (Apo1/CD95) is a transmembrane protein belonging to the nerve growth factor receptor family. It is expressed on a variety of cells, including activated T lymphocytes. Ligation of Fas with its natural ligand or with anti-Fas antibodies often results in the apoptotic death of the cell, making Fas an important mediator of down-regulating immune responses. The signal transduction pathways utilized by Fas are currently unknown, although tyrosine kinase activity has recently been strongly implicated. Here, we report that the tyrosine kinase p59fyn physically associates with Fas in Fas-sensitive cells. In addition, we show that activated T lymphocytes from fyn knockout mice exhibit elevated lifespans and reduced apoptosis in vitro compared to their normal counterparts. Furthermore, activated T lymphocytes from the fyn-deficient mice are less sensitive to killing by both anti-Fas antibody and Fas-ligand cytotoxic T cells. These results suggest that p59fyn plays an important role in Fas signal transduction.
Amino Acid Sequence↗
The HIV-1 regulatory genes tat and rev as targets for gene therapy.
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Acquired Immunodeficiency Syndrome↗
Inhibition of HIV-1 replication and reactivation from latency by tat transdominant negative mutants in the cysteine rich region.
Tat mutants (tat22, tat37 and tat22/37) were constructed in the transactivation domain, where cysteines at positions 22 or/and 37 were substituted with glycine and serine, respectively. These mutants were expressed either in a BK virus episomal vector or in the retroviral vector LXSN. Constitutive production of tat22 by Jurkat T cells in the context of both vectors blocked HIV-1 replication during lytic infection. Conversely, the tat37 mutant did not show any inhibitory activity and tat22/37 displayed a mild effect on HIV-1 infection only when expressed by the recombinant retrovirus. However, constitutive production of tat22/37 by the BK virus vector in Jurkat T cells chronically infected by HIV-1 was effective in blocking reactivation of viral replication induced by tumor necrosis factor-alpha or human herpesvirus-6. These results suggest that mutants in the transactivation domain of tat may be considered in designing alternative strategies to control HIV-1 replication and reactivation from latency during different phases of infection.
Base Sequence↗
The human immunodeficiency virus type-1 Tat protein upregulates Bcl-2 gene expression in Jurkat T-cell lines and primary peripheral blood mononuclear cells.
The regulatory Tat protein of human immunodeficiency virus type-1 (HIV-1) exerts a pleyotropic activity on the survival and proliferation of different cell types in culture. In this report, we investigated the effect of either endogenous or exogenous Tat on Bcl-2 proto-oncogene expression and cell survival in Jurkat T-cell lines and primary peripheral blood mononuclear cells. Stable and transient transfections of Jurkat cells with the cDNA of tat and a plasmid containing Bcl-2 promoter in front of CAT (Bcl-2 Pr/CAT) stimulated CAT activity and showed an increase of Bcl-2 mRNA and protein expression. This effect was specifically related to tat, because Jurkat cells transfected with the cDNA of tat in antisense orientation, tat carrying a mutation in the amino acid cys22-gly22, or the control vector alone (pRPneo-SL3) did not show any significant difference in Bcl-2 promoter activity with respect to parental Jurkat cells. We also observed a specific correlation between tat-induced Bcl-2 gene expression and inhibition of apoptosis induced by serum withdrawal. Our results suggest that the structural integrity of the activation domain of Tat was required for the promotion of the Bcl-2 promoter and Jurkat cell survival, because a single mutation in the aminoacid cys22 was sufficient to completely block the upregulation of Bcl-2 and inhibition of apoptosis. Moreover, picomolar concentrations of native or recombinant Tat were able to upregulate Bcl-2 expression both in Jurkat and primary peripheral blood mononuclear cells, suggesting that extracellular Tat, actively released by infected cells, may also play a significant role in suppressing apoptosis. An aberrant cell survival of lymphoid cells consequent to the upregulation of Bcl-2 may represent an additional pathogenetic mechanism that could help explain both the dysregulated immune response and the frequent occurrence of hyperplastic/neoplastic disorders in HIV-1-seropositive individuals.
Apoptosis↗
Granzyme B is inhibited by the cowpox virus serpin cytokine response modifier A.
The ability of cytolytic cells to cause apoptosis in target cells is in part due to the action of the serine proteinase granzyme B. We demonstrate that granzyme B is inhibited, with an association rate constant of 2.9 x 10(5) M-1 s-1, by the cowpox viral serpin cytokine response modifier A (CrmA). Previously we have shown CrmA to be an inhibitor of the cysteine proteinase interleukin-1 beta-converting enzyme (ICE). Thus the mechanism of CrmA involves the unusual ability to efficiently inhibit proteinases from two distinct catalytic classes, in this case serine and cysteine proteinases. Granzyme B and ICE are both used to combat viral infection, and we propose that cowpox virus uses CrmA to evade the contribution of these two proteinases. Thus, through CrmA, the virus may influence two of the pathways normally used to kill virus-infected cells: acting on endogenous proteinases such as ICE and on exogenous proteinases delivered by cytotoxic lymphocytes to infected cells.
Binding, Competitive↗
Site and mechanics of failure in normal and dystrophin-deficient skeletal muscle.
Partial or complete tearing of skeletal muscle occurs both in acute muscle injury and in some pathological muscle conditions. Despite the impact of such tearing on normal muscle function, few studies have examined the site or mechanism of muscle injury at cellular or subcellular levels of organization. The present study determines the ultrastructural location and mechanical conditions of tensile failure in normal mouse extensor digitorum longus muscles. All of these muscles failed near a myotendinous junction (MTJ), but within the muscle fibers, in a transverse plane coincident with the edge of an A-band. The breaking stress averaged 5.71 x 10(5) N/m2 for muscles stimulated tetanically during lengthening, and 5.01 x 10(5) N/m2 for unstimulated muscles. Breaking strain averaged 135%, and showed no dependence on the state of activation of the muscle. The energy absorbed by each muscle averaged 362.5 mJ/g in unstimulated muscle, and 613.2 mJ/g in the stimulated samples. In addition to the failure properties of normal muscle, the effect of dystrophin deficiency on the site and conditions of failure was determined using muscle from mdx mice, which lack dystrophin. The absence of dystrophin had no detectable effect on the stress, strain, or energy absorbed, regardless of the state of muscle activation. Unstimulated mdx muscle failed in the plane of an A-band, but tetanic stimulation produced failure in the reticular lamina of the tendon, just external to the MTJ, in 75% of the fibers in the mdx muscles. Although dystrophin's cytoplasmic location makes it unlikely that this unique mode of failure is due directly to the absence of the protein, failure in the reticular lamina may result from a difference in load distribution that accompanies the response of mdx muscle to dystrophin deficiency.
Animals↗
Language and thought disorder in schizophrenia: brain morphological correlates.
In this magnetic resonance imaging study, the authors analyzed the relationships between frontal and temporal lobe volumes, volumes of ventricular system subdivisions and clinical and neuropsychological aspects of language and thought disorder in a group of 19 young schizophrenic patients. Schizophrenics showed enlargement of lateral ventricles, especially of the central and occipital segments compared with 15 age and sex matched healthy controls but no differences were present in prefrontal, temporal lobe and superior temporal gyrus volumes. Prefrontal volume was inversely correlated with Thought, Language and Communication (TLC) scale total scores; left superior temporal gyral (STG) volume was positively correlated with verbal fluency test performance; higher total ventricular volume was significantly correlated with poor performance to a sentence generation test; STG laterality index was correlated with global TLC scores, the more severe the thought and language disorders, the relatively smaller the left and larger the right STG. These results suggest a complex neuroanatomical substrate for thought and language disorders in schizophrenia.
Adult↗
Tat-expressing Jurkat cells show an increased resistance to different apoptotic stimuli, including acute human immunodeficiency virus-type 1 (HIV-1) infection.
Human CD4+ T lymphoblastoid Jurkat cells were stably transfected with two different plasmid vectors containing the cDNA of human immunodeficiency virus-type 1 (HIV-1) tat gene under the control of either the promoter of simian virus 40 (pRPneo/tat) or the long terminal repeat region of SL3 murine leukaemia virus (pRPneo/SL3/tat). Both pRPneo/tat and pRPneo/SL3/tat Jurkat cell lines showed a constant and high production of bioactive Tat in transient co-transfection assays with an HIV-1 long terminal repeat (LTR)-chloramphenicol acetyltransferase (CAT) reporter plasmid. Tat-positive and mock-transfected Jurkat cells were cultured with various cytotoxic agents, which have been associated to the progressive loss of CD4 T-lymphocytes characteristic of HIV-1 disease. In the presence of recombinant tumour necrosis factor-alpha (TNF-alpha), anti-fas antibody, Leu3a anti-CD4 antibody, the percentage of apoptosis, evaluated in a 24-72 h short-term assay, was lower (P < 0.05) in tat-positive Jurkat cells than in mock-transfected controls. The low susceptibility to the cytotoxic activity of TNF-alpha and anti-fas antibody of tat-transfected cells was confirmed by counting viable cells up to 15 d of culture. Also, recombinant Tat protein was able to prevent the increase of apoptosis induced in mock-transfected Jurkat by TNF-alpha. Of note, tat-expressing cells showed a better survival with respect to mock-transfected control cells even when acutely infected with high doses (500,000 cpm of reverse transcriptase) of HIV-1 (strain IIIB) or treated with heat-inactivated HIV-1. These data demonstrate that the expression of the regulatory HIV-1 Tat protein is able to rescue Jurkat lymphoblastoid cells from apoptosis induced by a variety of cytotoxic agents. Since Tat protein expression is restricted to the initial phases of an active HIV-1 replication, the anti-apoptotic effect of Tat could have the physiological significance of selectively protecting HIV-1 producing cells from death, at least for the time necessary to allow virus production and spreading.
Antibodies, Monoclonal↗