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Results for “Latent diffusion”

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At least 199 records · Page 11Linked to original sources

PubMed1998

[Analysis of etiological agents and death-relating factors of pulmonary infections in immunocompromised patients].

OBJECTIVE: To explore the distribution of etiological agents and death-relating factors of pulmonary infections in immunocompromised hosts(ICH). METHOD: 80 patients of pulmonary infections in ICH confirmed by etiological and(or) pathological diagnosis were retrospectively analyzed. RESULT: The distribution of etiological agents of pulmonary infections (except for cytomegalovirus, CMV): common bacteria 56%, mycobacterium tuberculosis 29%, fungus 11%, pneumocystis carinii 4%. Mortality of pulmonary infections in ICH showed significant difference between age 67% (> or = 60 years): 48% (< 60 years), bacteremia 86% (yes): 45% (no), white blood cell count 67%, 87% (> 10 x 10(9)/L, < 4.0 x 10(9)/L): 23% (4.0-10) x 10(9)/L, extent of lesions in x-ray film 65% (diffuse): 23% (local) (P < 0.05, P < 0.01), however, there was no obvious difference in sex, underlying diseases, types of etiological agents, mixed infections. CONCLUSION: Bacteria was one of the most common etiological agents of pulmonary infections in ICH, the latent reactivation and relapse of pulmonary tuberculosis in ICH should be emphasized sufficiently. The preliminary analysis of death-relating factors showed: age, bacteremia, white blood cell count, extent of lesions in x-ray film were related to the prognosis of pulmonary infections in ICH.

Adult↗

PubMed1993

Transforming growth factor-beta expression and natural killer cell responses during virus infection of normal, nude, and SCID mice.

The experiments presented here assess the contribution of T cells to NK cell regulation and transforming growth factor-beta (TGF-beta) production. The kinetics of NK cell activation in the absence of T cells was evaluated by comparing responses in athymic nude and SCID mice to those in normal C3H/HeN, C57BL/6, and BALB/c mice during lymphocytic choriomeningitis virus (LCMV) infection. T cell-deficient mice exhibited high NK cell activity for longer periods of time post-infection. To determine whether the reduction in NK cell activation at later times post-infection of normal mice resulted from induction of negative regulatory elements, mice were treated with the chemical IFN and NK cell inducing agent polyinosinic-polycytidylic acid (poly I:C). Although poly I:C induced plasma IFN in both uninfected and LCMV-infected normal mice, NK cell activity was elevated in the uninfected mice only. In vivo expression of TGF-beta protein in normal and T cell-deficient mice was evaluated by immunohistochemical studies on splenic sections. TGF-beta proteins were not detected in sections from uninfected mice but were induced in all strains during infection. High levels of TGF-beta proteins were localized to discrete cells, and diffuse staining was observed along marginal zones. The ability of the splenic leukocytes to release TGF-beta into conditioned media was evaluated in the Mv 1 Lu biologic assay. Transient acid treatment to release active factor from the latent form and use of specific neutralizing antibodies demonstrated that leukocytes from all strains of infected mice had released latent TGF-beta 1 into conditioned media. However, cells from infected nude or SCID mice produced substantially less active TGF-beta than those isolated from normal mice. Production of biologically active TGF-beta 1 was dependent upon the presence of T cells in normal mice, as in vivo depletion of CD4+ and CD8+ T cells by antibody treatment resulted in augmented NK cell activity and loss of active factor production. The lack of TGF-beta production was accompanied by increased NK cell numbers; at late times post-infection, T cell-deficient C57BL/6-nude mice had almost twice as many NK1.1+CD3- cells per spleen compared with T cell-containing C57BL/6 littermate control mice. Treatment with active TGF-beta 1 reduced the numbers of NK cells per spleen in infected nude mice to the levels found in infected littermate controls.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed2004

Epstein-Barr virus-associated composite lymphoma composed of peripheral T-cell lymphoma and an anaplastic variant of a diffuse large B-cell type of non-Hodgkin's lymphoma and strongly expressing p53 protein.

We report a case of composite lymphoma consisting of peripheral T-cell lymphoma and an anaplastic variant of diffuse large B-cell lymphoma (DLBCL) and associated with Epstein-Barr virus (EBV) infection and strong p53 expression. A 65-year-old Japanese woman developed fever and generalized lymphadenopathy. A biopsy of the cervical node revealed the morphology of malignant lymphoma with 2 kinds of lymphoma coexisting in 1 lymph node. One lymphoma type consisted of immunoblastic large cells with the T-cell marker phenotype CD3+, CD45RO/UCHL-1+, CD20/L26-, CD79-, CD10-, CD30-, and CD15-; the other type consisted of large cells with abundant cytoplasm and pleomorphic nuclei with the marker phenotype CD79+, CD20/L26+, CD45RO/UCHL-1-, CD3-, CD10-, CD30+, NPM/ALK-, and CD15-. Therefore, the diagnosis was composite lymphoma of peripheral T-cell lymphoma and an anaplastic variant of DLBCL, stage IVB, because the patient had bone marrow involvement with peripheral T-cell lymphoma. The biopsy led to findings of latent type II EBV-associated lymphoma in both the peripheral T-cell lymphoma and the anaplastic variant of DLBCL as the result of positive signals for EBV small RNAs by in situ hybridization, positive immunostaining results for EBV latent membrane protein 1 antibody, and negative immunostaining results for EBV nuclear antigen 2. Immunostaining of the mass with p53 antibody also yielded positive results for both types of lymphoma cells. This case suggests that the immunocompromised state of this patient with EBV-related peripheral T-cell lymphoma allowed the emergence of an EBV-related anaplastic variant of DLBCL and suggests a close relationship between p53 expression and latent EBV infection.

Aged↗

PubMed1994

Pediatric thyroid cancer after the Chernobyl disaster. Pathomorphologic study of 84 cases (1991-1992) from the Republic of Belarus.

BACKGROUND: During the initial period after the Chernobyl accident, large amounts of radioactive iodine were released in fallout, resulting in serious exposure to the thyroid gland in the residents of areas around the nuclear power station. Beginning in 1990, a definite increase in the incidence of thyroid cancer was noted in children of the Republic of Belarus. METHODS: Morphologic and clinical features of 84 cases of post-Chernobyl thyroid carcinoma in Belarussian children from 5 to 14 years of age are reported. The latent period for tumor development was 4-6 years, with a mean of 5.8 years. RESULTS: Papillary carcinoma was found in 83 patients and medullary carcinoma in one. Besides typical papillary carcinoma (14%), solid (34%), follicular (33%), mixed (10%), and diffuse sclerosing (9%) variants were observed. The follow-up period ranged from 8 months to 2.5 years. One patient died, local recurrence developed in 2, and cervical lymph node metastases developed in 10. To date, the incidence of local recurrence or metastatic disease after surgery was significantly higher in patients 5-8 years of age and in residents of areas nearest to the Chernobyl station. CONCLUSIONS: Post-Chernobyl pediatric thyroid carcinoma is characterized by a short latency, a higher proportion of tumors arising in young children, and an almost equal sex ratio. Microscopically, these tumors were usually aggressive, often demonstrating intraglandular tumor dissemination (92%), thyroid capsular and adjacent soft tissue invasion (89%), and cervical lymph node metastases (88%). Papillary carcinoma was diagnosed in 99% of cases, with an unusually high frequency of solid growth patterns. Morphologic changes in nonneoplastic thyroid tissue were present in 90% of the glands, and the most specific findings were vascular changes and perifollicular fibrosis.

Accidents↗

PubMed1997

Theoretical calculation and prediction of Caco-2 cell permeability using MolSurf parametrization and PLS statistics.

PURPOSE: To statistically model the permeability across Caco-2 cell monolayers using theoretically computed molecular descriptors and multivariate statistics. METHODS: Seventeen structurally diverse compounds were investigated. The program MolSurf was used to compute theoretical molecular descriptors related to physico-chemical properties such as lipophilicity, polarity, polarizability and hydrogen bonding. The multivariate Partial Least Squares Projections to Latent Structures (PLS) method was used to delineate the relationship between the permeability across Caco-2 cell monolayers and the theoretically computed molecular descriptors. RESULTS: Excellent statistical models were derived. Properties associated with hydrogen bonding had the largest impact on diffusion through the monolayers and should be kept at a minimum to promote high permeability. High lipophilicity and the presence of surface electrons, i.e. valence electrons, which are not tightly bonded to the molecule, were also found to have a favorable influence to achieve high permeability. CONCLUSIONS: The results indicate that theoretically computed molecular MolSurf descriptors in conjunction with multivariate statistics of PLS type can be used to successfully model permeability across Caco-2 cell monolayers and, thus, differentiate drugs with poor permeability from those with acceptable permeability at an early stage of the preclinical drug discovery process.

Caco-2 Cells↗

PubMed2003

Hepatocellular carcinoma in a hepatitis B 'x' transgenic mouse model: A sequential pathological evaluation.

BACKGROUND: The introduction of transgenic technology has made it possible to study the steps of carcinogenesis and directly establish the link between viral subgenomic fragments and specific types of cancer. Research directed at hepatitis B virus (HBV)-related carcinogenesis has benefited from this technology. We present a detailed pathological evaluation of the sequential steps of hepatocarcinogenesis in a hepatitis B 'x' (HBx) transgenic mouse model. In this model, the transgene incorporates the region encoding amino acids 58-154 of the HBV X protein and the murine c-myc gene. This model demonstrated changes in the liver from birth with foci of multicentric dysplasia evolving into nodules and overt hepatocellular carcinoma between 20 and 28 weeks. METHODS AND RESULTS: The hepatocytes were mitotically active and showed increased proliferative capacity soon after birth, with exponential increase thereafter. This was accompanied by a high rate of apoptosis, which later declined as the tumors developed. Other functional and immunophenotypic characteristics included a high c-myc expression in the neoplastic lesions, no alteration in p53 expression, and no alteration in the expression of hepatic enzymes except for diffuse expression of succinic dehydrogenase. CONCLUSION: The entire process illustrates the disturbances of cell growth and death because of the collaborative influence of HBx and c-myc genes that result in the development of hepatocellular carcinoma after a prolonged latent period.

Animals↗

PubMed1993

Retinoic acid is a negative regulator of the Epstein-Barr virus protein (BZLF1) that mediates disruption of latent infection.

Disruption of latent Epstein-Barr virus (EBV) infection is induced by the key immediate-early protein BZLF1 (or Z, a member of the basic leucine-zipper family), which transactivates the viral early promoters. Viral reactivation is marked by renewed synthesis of early gene products such as EBV early antigen-diffuse (EA-D). Retinoic acid has been previously shown to inhibit reactivation of EBV infection. Retinoic acid responsive receptors are known to act as positively regulating transcription factors but can also negatively regulate AP-1 responsive genes. Here we demonstrate that the retinoic acid receptor alpha (RAR alpha) and retinoid X receptor alpha (RXR alpha) inhibit the ability of the Z protein to transactivate the viral early promoter BMRF1, which directs transcription of EA-D. Z can also reciprocally inhibit RAR alpha- and RXR alpha-induced activation of an autoregulated cellular promoter for the RAR beta gene (BRE) through a non-DNA binding mechanism. RXR alpha inhibits Z from binding to the AP-1 motif in the BMRF1 promoter and, reciprocally, Z inhibits RAR alpha from binding to its retinoic acid response element in the BRE promoter. Furthermore, a glutathione-S-transferase-RXR alpha fusion protein can interact directly with the Z protein. These results suggest that a direct protein-protein interaction between Z (the viral protein) and RAR alpha and RXR alpha (cellular proteins) can modulate the reactivation of latent EBV infection.

Animals↗

PubMed2001

Development of latent fingerprints on metallic surfaces using electropolymerization processes.

We propose a new process for developing latent fingerprints on metal items, applicable to unfired weapons made of Ergal in particular. The method is based on the presence of fatty acids that are contained in fingerprints and act as an insulator on the surface where fingerprints are to be developed. The process of polymerization occurs on the metal portions left untouched by finger contact. Hence, the developing process results as a negative pattern of the original fingerprint. The reaction consists in the electropolymerization of pyrrole and substituted porphyrins, i.e., tetra (o-aminophenyl) porphyrine: radical-cations are generated on superficial nucleation sites by oxidation of monomer, close to the electrode surface; subsequently, the radical species react with the neutral monomer, which begins to diffuse to the electrode. We have also studied the polymer's morphology by means of SEM and AFM, in order to find a correlation between the reagent to be used and the quality of the enhancement process. These are only preliminary results; however, they show that the suggested method is a new way to increase the rate of success in developing latent fingerprints on metal surfaces. In this regard, it may be considered complementary to other conventional procedures, due to the low costs of the instruments and reagents, and the rapidity and simplicity of the treatment.

Dermatoglyphics↗

PubMed2006

The DNA binding activity of p53 displays reaction-diffusion kinetics.

The tumor suppressor protein p53 plays a key role in maintaining the genomic stability of mammalian cells and preventing malignant transformation. In this study, we investigated the intracellular diffusion of a p53-GFP fusion protein using confocal fluorescence recovery after photobleaching. We show that the diffusion of p53-GFP within the nucleus is well described by a mathematical model for diffusion of particles that bind temporarily to a spatially homogeneous immobile structure with binding and release rates k1 and k2, respectively. The diffusion constant of p53-GFP was estimated to be Dp53-GFP=15.4 microm2 s-1, significantly slower than that of GFP alone, DGFP=41.6 microm2 s-1. The reaction rates of the binding and unbinding of p53-GFP were estimated as k1=0.3 s-1 and k2=0.4 s-1, respectively, values suggestive of nonspecific binding. Consistent with this finding, the diffusional mobilities of tumor-derived sequence-specific DNA binding mutants of p53 were indistinguishable from that of the wild-type protein. These data are consistent with a model in which, under steady-state conditions, p53 is latent and continuously scans DNA, requiring activation for sequence-specific DNA binding.

Active Transport, Cell Nucleus↗

PubMed1978

Comparative immunological studies on arylsulfatase in bacteria of the family Enterobacteriaceae: occurrence of latent arylsulfatase protein regulated by sulfur compounds and tyramine.

The arylsulfatases of 21 strains of the family Enterobacteriaceae were compared by measuring their enzymatic activities and immunological reactivities. Enzyme formation under repressing, nonrepressing, and derepressing conditions was tested. Antiserum prepared against pure arylsulfatase from Klebsiella aerobgenes W70 was tested against the enzyme extracts from the strains using double diffusion, quantitative precipitation, and immunoelectrophoresis. No close relationship was found between arylsulfatase activity and immunological cross-reactionship was found between arylsulfatase activity and immunological cross-reactivity. The strains in the family Enterobacteriaceae could be divided into two groups on the basis of the immunological properties of their enzyme. Antisera formed a precipitin band with both active and inactive enzyme proteins from Escherichia, Citrobacter, Salmonella, Klebsiella, and Enterobacter, but not with the proteins from Serratia, Proteus, and Erwinia, even though some strains of these species had enzyme activity. It was also found that the formation of arylsulfatase proteins, irrespective of whether they had enzyme activity, were under regulation by sulfur compounds and tyramine.

Arylsulfatases↗

PubMed1999

Primary anaplastic large cell lymphoma of the central nervous system.

Central nervous system (CNS) involvement is extremely rare in anaplastic large cell lymphoma (ALCL), and in children only isolated cases have been reported, mainly as secondary CNS involvement. A case of fatal primary ALCL of the brain in a 13-year-old white boy is reported. Magnetic resonance imaging of the brain showed decreased absorption in T1- and T2-weighted image showed a hyperintense signal in the right parietal lobe and 2 masses in the right frontal lobe. A frontal lobe biopsy showed a pleomorphic neoplasm diffusely infiltrating the brain parenchyma and composed of large cells with bizarre, often polylobated or horseshoe-shaped nuclei. Immunohistochemical stains showed diffuse strong positivity for CD30, anaplastic lymphoma kinase protein (ALK-1), p80, leucocyte common antigen, CD45RO (UCHL1), and focal staining for epithelial membrane antigen. Immunostainings for cytokeratins, monocyte-macrophage, and B-cell markers were negative. Epstein-Barr virus latent membrane protein was not detected. To the best of our knowledge, there is only 1 case of primary ALCL of the brain in childhood previously reported in the literature. Before the biopsy, both cases were clinically misdiagnosed as mycobacterial CNS infection. Therefore, primary ALCL should also be included in the differential diagnosis when a mycobacterial CNS infection is suspected in pediatric patients; a careful cytological evaluation of the cerebrospinal fluid or cerebral biopsy are essential for an accurate diagnosis.

Adolescent↗

PubMed2005

Competing thermal activation mechanisms in the meltinglike transition of Na(N) (N = 135-147) clusters.

The meltinglike transition in unsupported icosahedral Na(N)() clusters, with N = 135-147, has been studied by isokinetic molecular dynamics simulations based on an orbital-free version of density functional theory. A maximum in the melting temperature, T(m), is obtained for Na141, while the latent heat, deltaE, and entropy of melting, deltaS, are maximal for Na147. These observations are in close agreement with calorimetric experiments on N clusters. The size evolution of deltaS is rationalized by the emergence of important premelting effects associated with the diffusive motion of atomic vacancies at the cluster surface. The precise location of the maximum in T(m) is explained in terms of two different thermally activated structural instability mechanisms which trigger the meltinglike transition in the size ranges N = 135-141 and N = 141-147, respectively.

Letter↗

PubMed1976

The neuropathology of progressive rubella panencephalitis of late onset.

The clinicopathological changes in a case of progressive rubella panencephalitis of late onset have been presented. The prominent pathological findings in the brain included diffuse destruction of white matter with perivascular inflammatory cells and gliosis, moderate neuronal loss, numerous amorphous vascular deposits in the white matter and severe generalized cerebellar atrophy. These changes are compared and contrasted with those found in congenital rubella and other latent viral illnesses.

Adult↗

PubMed2004

Epstein-Barr virus-induced transformation of cutaneous plasmacytoma into CD30+ diffuse large B-cell lymphoma.

A unique, previously unreported case of transformation of cutaneous plasmacytoma into CD30+ large B-cell lymphoma is described. Both neoplastic components were immunophenotypically distinct. The plasma cells were CD20-, CD30-, CD43+, CD45+, lambda +; the blasts were CD20+, CD30+, CD43-, and CD45-. The large B-cell lymphoma has gradually become a predominant component of the neoplastic nodules. While plasma cells and blasts were both positive for Epstein-Barr virus-encoded nuclear RNAs (EBER-1), the EBV-latent membrane antigen 1 (EBV-LMP1) was expressed only in the minority of the blasts and not in the plasma cells. The neoplastic process has remained confined to the skin for more than six years since its development.

Aged↗

PubMed1984

Effect of the nonionic detergent Triton X-100 on mitochondrial succinate-oxidizing enzymes.

Specific activities of succinate:coenzyme Q reductase, ubiquinone:cytochrome c reductase, cytochrome oxidase, succinate:cytochrome c reductase, succinate oxidase, and ubiquinol oxidase have been measured in rat liver mitochondria in the presence of Triton X-100. The last three activities are much more sensitive to Triton X-100 than the first ones; the data suggest that the electron transport chain components cannot react with each other in the presence of the detergent. At least in the case of succinate:cytochrome c reductase, reconstitution of the detergent-treated membranes with externally added phospholipids reverses the inhibition produced by Triton X-100. These results support the idea that the respiratory chain components diffuse at random in the plane of the inner mitochondrial membrane; the main effect of the detergent would be to impair lateral diffusion by decreasing the area of lipid bilayer. When detergent-treated mitochondrial suspensions are centrifuged in order to separate the solubilized from the particulate material, only the first three enzyme activities mentioned above are found in the supernatants. After centrifugation, a latent ubiquinol:cytochrome c oxidase activity becomes apparent, whereas the same centrifugation process produces inhibition of cytochrome c oxidase in the presence of certain Triton X-100 concentrations. These effects could be due either to a selective solubilization of regulatory or catalytic subunits or to a conformational change of the enzyme-detergent complex.

Animals↗

PubMed2004

Improving tuberculosis therapy completion after jail: translation of research to practice.

Inmates have high rates of latent tuberculosis infection (LTBI), but inmates are often released early and do not complete therapy in the community. This study evaluated the translation of results from a randomized trial to improve therapy completion to usual care in a county jail using Rogers' Diffusion of Innovation theory. Inmates who received a single education in the randomized trial in 1998-1999 (study group) were compared to inmates educated by Jail Discharge Planners in 2002-2003 (usual care group). Outcomes were rates of completion of a visit to the TB clinic and completion of therapy. Subjects in the usual care group were significantly less likely to go to clinic in the 30-day period after release (relative risk 0.84, 95% confidence interval 0.75-0.95). The transfer of an educational protocol did not achieve results seen under study conditions, mostly because of implementation fidelity. The educational session in the usual care period for 81.0% of inmates took 5 min, as compared to 10-15 min during the randomized trial. Differences in personnel administering the protocol, training, high turnover and time available may also account for lower rates seen. Practical clinical trials should focus on the context of care as well as the intervention and should have participation by those who will be implementing results.

Adult↗

PubMed1995

X-ray imaging using amorphous selenium: inherent spatial resolution.

This is a theoretical study of the inherent spatial resolution of the latent image on the surface of an amorphous selenium (a-Se) plate used for diagnostic x-ray imaging. The following effects are considered: (A) ranges of primary photoelectrons; (B) reabsorption of K fluorescence; (C) reabsorption of Compton scattered photons; (D) diffusion; (E) the geometric effect due to oblique incidence of x rays; (F) electrostatic effect; and (G) the space charge effect. The modulation transfer function of a-Se in the diagnostic x-ray energy range has been estimated. In conclusion, (A) and (E) are the main factors limiting the resolution, and for diagnostic x rays, the inherent spatial resolution of a-Se plates is much better than that of CsI layers used in x-ray image intensifiers.

Humans↗

PubMed1985

Behavior of transplanted large granular lymphocyte leukemia in Fischer 344 rats.

The behavior of transplanted large granular lymphocyte leukemia was studied by isogeneic inoculation of 55 young F344 rats. A high percentage of transplants were successful, showing a dose-dependent latent phase followed by weight loss, exponential increase of tumor cells, and widespread infiltration. Serial passage of tumor cells appeared to increase malignancy by decreasing longevity. Grossly, there was splenomegaly, variable lymphadenopathy, and petechial hemorrhages on the lungs, lymph nodes, and brain. Diffuse infiltration of tumor cells caused morphologic changes identical with spontaneous large granular lymphocyte leukemia including splenic lymphoid depletion, hepatocellular necrosis, tumor cell erythrophagocytosis, and femoral medullary endosteal bone proliferation. Clinicopathologic features were also similar to spontaneous large granular lymphocyte leukemia. There was immune-mediated hemolytic anemia and thrombocytopenia, which coincided with development of leukemia, as well as hyperbilirubinemia and elevated serum enzymes, indicative of liver disease. It was concluded that isogeneic transplantation of large granular lymphocyte leukemia is not only highly successful but reproduces the pattern and clinical syndrome of the spontaneous tumor including the important paraneoplastic syndrome of hemolytic anemia and thrombocytopenia.

Anemia, Hemolytic, Autoimmune↗