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Query: UMLS:C0021311 (Infection)
 38,178 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Meropenem and comparator antibiotics, including ceftriaxone, ceftazidime, benzyl penicillin and a combination of ampicillin plus gentamicin, were evaluated in a model of bacterial meningitis in the guinea-pig. The model is an acute infection in which challenge with each organism, if untreated, causes an increase in numbers of white blood cells, elevation of protein concentrations and 6-8 log10 cfu/mL of bacteria in the CSF. Infections caused by Haemophilus influenzae, Neisseria meningitidis, three strains of Streptococcus pneumoniae (two penicillin-resistant), Escherichia coli, Pseudomonas aeruginosa and Listeria monocytogenes all responded to meropenem, which was as active as the comparator agents in all studies, and was more active in most. Of particular note were the results seen against S. pneumoniae (penicillin-resistant) infections, in which meropenem was significantly more effective than ceftriaxone. Also notable were results from the P. aeruginosa infection where meropenem, at low doses, was more effective than ceftazidime. Activity against L. monocytogenes was equivalent to that produced by treatment with the combination of ampicillin plus gentamicin, even when treatment was delayed. These results show that, in an animal model, meropenem penetrates into CSF in concentrations sufficient to produce significant reductions in the numbers of common and less common pathogens.
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PMID:Efficacy of meropenem in experimental meningitis. 854 1

The human melanoma tumor Ags, MART1 and gp100, are specifically recognized by HLA-A2-restricted CD8+ CTLs derived from melanoma patients and appear to be involved in tumor regression. In order to develop immunizing vectors for the treatment of patients with metastatic melanoma, replication-defective recombinant adenoviruses, Ad2CMV-MART1 and Ad2CMV-gp100, which encode these tumor Ags, have been generated. Infection of non-Ag expressing HLA-A2+ cell lines A375 and MDA-231 with the vectors resulted in recognition by Ag-specific CTLs as demonstrated by specific target cell lysis and release of cytokines, including IFN-gamma, TNF-alpha, and granulocyte-macrophage-CSF. Sodium butyrate and TNF-alpha can further augment adenovirus-mediated transgene expression and increase recognition by specific CTLs. Although adenovirus-infected cells expressed the E3/19K protein at detectable levels, significant reduction of surface MHC class I expression was observed in only 3 of 10 tumor cell lines infected with either Ad2CMV-MART1 or Ad2CMV-gp100. Because of the suspected homology between the human MART1 and gp100 genes and their murine counterparts, we immunized C57BL/6 mice with these recombinant adenoviruses and demonstrated that immunization with Ad2CMV-gp100 could protect mice from murine melanoma B16 challenge administered intradermally. Depletion of CD8+ but not CD4+ T cells in vivo from Ad2CMV-gp100-vaccinated mice eliminated the protective effect. The anti-gp100 T cells induced by Ad2CMV-gp100 vaccinated appeared to be responsible for the protection. Thus, these recombinant adenoviruses encoding tumor Ags may be useful as vaccines to induce specific T cell immunity for cancer therapy.
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PMID:Antigen-specific tumor vaccines. Development and characterization of recombinant adenoviruses encoding MART1 or gp100 for cancer therapy. 854 23

The ras gene products play a fundamental role in signal transduction in haemopoiesis. In this study, we have examined the effects of ras upon haemopoietic cell proliferation and differentiation, using two human cell lines which represent different stages of haemopoietic cell maturation. When a mutant H12-ras gene (codon 12: gly-->asp) was expressed in the monoblastic cell line, U937, marked inhibition of growth was seen together with morphological, functional and immunophenotypic evidence of monocytic maturation. Infection of U937 cells with a c-myc retrovirus produced similar changes strongly suggesting that Myc plays an important role in this action of Ras. By contrast, expression of H12-ras promoted factor-independent growth of the multipotent cell line, TF-1. Furthermore, mutant ras dramatically enhanced the growth of TF-1 cells in the presence of added GM-CSF or erythropoietin, but did not influence the state of differentiation of these cells. These data clearly indicate that in haemopoietic cells, Ras may promote either proliferation or differentiation depending upon cell type and/or state of maturation.
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PMID:Mutant ras promotes haemopoietic cell proliferation or differentiation in a cell-specific manner. 855 43

Infection remains a major cause of morbidity and mortality following CSF shunt procedures. In this study 191 shunt procedures carried out from January 1981 to December 1992 in a series of 81 infants (less than 6 months old) were retrospectively analyzed for possible risk factors. The overall surgical infection rate was 7.8%, with 15 infections occurring in 14 patients (17.2%). No significant difference in the rate of infections was found in relation to sex, birth weight, gestational age, and type of shunt procedure (primary insertion/revision). The occurrence of other infections during the period of shunt surgery did not influence the infection risk either. Intraventricular hemorrhage and central nervous system infections as causes of the hydrocephalus were found to correlate with septic risk. Young age (less than 6 months) seems to represent the main risk factor, and this is related both to the immunologic deficiency and to the particular features of residential bacterial flora in this age group.
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PMID:Cerebrospinal fluid shunt infections in infants. 860 81

The most frequent neurological complication of AIDS is a dementia-like syndrome. Power and collaborators (J Virol 1994; 68:4643-4649) have reported an association between the clinical signs of AIDS dementia and the amino acid composition of two positions (305 and 329) within the V3 region of HIV-1 strains amplified from brain tissue. Similarly, we analyzed position 305 in the V3 region of HIV-1 present in the brain or cerebrospinal fluid of 25 nondemented subjects at different clinical stages of HIV-1 infection. Our results are, however, at variance with the findings presented by Power and colleagues. Histidine, found to be common among sequences derived from demented patients, was also present in the majority (16 of 25) of nondemented patients analyzed by us. In the hands of Power and colleagues, sequences derived from nondemented patients contained proline at position 305. None of our patients had proline in this position. We also asked the question whether the presence of a specific amino acid at position 305 of the V3 loop is linked to an increased capacity of HIV-1 isolates to infect primary microglial cells, the major target cell for HIV-1 infection in the brain. Primary HIV-1 isolates derived from blood and cerebrospinal fluid of five patients, two asymptomatic and three AIDS patients, were used to infect microglia cell cultures. Infection was monitored by syncytium formation and by p24 antigen release in the culture supernatant. All but one of the paired blood/CSF isolates replicated in human brain cultures. Replication occurred independently from the amino acid present at position 305 of the V3 region of the viral envelope. Our results indicate that the majority of HIV-1 isolates, even derived during the asymptomatic stage, have the capacity to infect microglial cells. The relevance of viral envelope sequences in determining tropism for microglial cells and development of neurological symptoms remains an open question.
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PMID:HIV type 1 V3 sequences and the development of dementia during AIDS. 867 1

In vitro beta-lactam antibiotics like ceftriaxone and penicillin G sodium have been shown to be active against Borrelia burgdorferi. Results of quantitative determinations of both antibiotic substances in the CSF for children are limited. Seventy-five children (median age 96 months, range 10 to 176 months) with probable or definite neuroborreliosis were treated with ceftriaxone (1 x 50-90 mg/kg/day) or penicillin G sodium (4 x 80,000-120,000 IU/kg/day) intravenously. On day 10 of therapy levels of penicillin G sodium (1,1.5,2,3,4, 5, or 6 h after i.v. administration), and ceftriaxone (1,2,4,6,12 or 24 h after i.v. administration) in serum and CSF were measured with a micro agar diffusion bioassay. Results demonstrate that after 5 h penicillin G sodium in CSF was above the minimal inhibitory concentration (MIC) but after 6 h penicillin G sodium levels were below the determination limit in 60% of the cases. All ceftriaxone results in CSF-even after 24 h-were above MIC. Penicillin G sodium serum values ranged from 46.6 to 0.1 mg/L (1 to 6 h post dose) and ceftriaxone serum values from 261 to 5 mg/l (1 to 24 h post dose). The role of penicillin G sodium and ceftriaxone and administration intervals of both antibiotics in the therapy of neuroborreliosis in children are discussed.
Infection
PMID:beta-lactam antibiotics in the treatment of neuroborreliosis in children: preliminary results. 874 Jan 17

The authors, since 1985, have used 587 Madreporic Coral grafts as bone substitute in a total of 183 patients, among them in 80 cases for repair of cranial base bone defects. They report their long-term results. Partial resorption to about 40% of the initial volume occurred in almost all cases within 8 to 10 months, with complete resorption after about one year. 20% of the coral blocks moved spontaneously or split into pieces, but could easily be withdrawn rhinoscopically through the nostrils. No CSF leakage was noticed afterwards. The local infection rate was only 4%, always close to the basal coral graft. This is lower than the infection rate after using autologous bone harvested from the inner table of the bone flap (20%). Infections were cured by removal of the coral graft. Despite the mentioned draw backs, Madreporic Coral graft implants can be recommended as bone substitute in cranial base surgery: 1. The material simplifies the surgical procedure; 2. Harvesting of autologous bone is no longer necessary; 3. Transmission of infections like AIDS, Hepatitis C or Creutzfeld-Jacob-disease can be avoided with certainty.
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PMID:Madreporic coral for cranial base reconstruction. 8 years experience. 874 67

Infection of cells of the central nervous system by the human immunodeficiency virus type-1 (HIV-1) leads to HIV-1-associated neuropathology. Recent studies have demonstrated the importance of long terminal repeat (LTR) binding sites in determining the pathogenicity of HIV. Here we have investigated the presence and the functional role of transcription factors that have the potential to interact, directly or indirectly, with the nuclear receptor-responsive element in the LTR of HIV-1, in different human cell lines of the brain. Cotransfection experiments showed that in oligodendroglioma TC-620 cells, the retinoic acid receptor and the retinoid X receptor activate LTR-driven transcription in the absence of ligand. Addition of all-trans- or 9-cis-retinoic acid reverses this effect. In contrast, in astrocytoma, neuronal, and microglial cells, no significant effect of the retinoid acid pathway was detected. This retinoid response is mediated by distinct molecular interactions in the lymphotropic LAI and the neurotropic JR-CSF HIV-1 strains. Moreover, retinoid receptors were found to antagonize the chicken ovalbumin upstream promoter transcription factor- as well as the c-JUN-mediated LTR transactivation. Our findings demonstrate the importance of the retinoic acid signaling pathway and of cross-coupling interactions in the repression of HIV-1 LTR gene expression.
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PMID:Regulation of human immunodeficiency virus type 1 gene transcription by nuclear receptors in human brain cells. 879 69

The HIV-1 RNA in plasma and CSF samples from 40 HIV-1 infected patients was measured by a polymerase chain reaction (PCR) technique. The possible implication of cytokines in HIV-1 replication was investigated by measuring the concentrations of tumor necrosis factor alpha (TNF-alpha), macrophage colony stimulation factor (M-CSF) and interleukin-6 (IL-6) in these fluids. HIV-1 RNA was quantified in all plasma samples and in 87.5% of the CSF samples. CSF HIV-1 RNA titers did not correlate with the stage of disease or the CD4+ T cell counts, unlike the plasma HIV-1 RNA titers. These results were confirmed when patients with a blood brain barrier damage, as assessed by the CSF/ plasma albumin ratio, were excluded from the analysis. TNF-alpha levels were statistically correlated with the HIV-1 RNA in plasma and CSF. These data demonstrate that HIV-1 replication in the CSF at each clinical stage can be accurately measured with PCR and, although the titers of HIV-1 RNA copies in the CSF are correlated with those in the plasma, the magnitude of HIV-1 replication in CSF is not directly linked to the stage of disease, or to the CD4+ T cell count. The significance of early high levels of HIV-1 RNA in CSF is now being studied prospectively.
Infection
PMID:HIV-1 replication in the plasma and cerebrospinal fluid. 892 47

A panel of primary syncytium-inducing (SI) human immunodeficiency virus type 1 isolates that infected several CD4+ T-cell lines, including MT-2 and C8166, were tested for infection of blood-derived macrophages. Infectivity titers for C8166 cells and macrophages demonstrated that primary SI strains infected macrophages much more efficiently than T-cell line-adapted HIV-1 strains such as LAI and RF. These primary SI strains were therefore dual-tropic. Nine biological clones of two SI strains, prepared by limiting dilution, had macrophage/C8166 infectivity ratios similar to those of their parental viruses, indicating that the dual-tropic phenotype was not due to a mixture of non-SI/macrophage-tropic and SI/T-cell tropic viruses. We tested whether the primary SI strains used either Lestr (fusin) or CCR5 as coreceptors. Infection of cat CCC/CD4 cells transiently expressing Lestr supported infection by T-cell line-adapted strains including LAI, whereas CCC/CD4 cells expressing CCR5 were sensitive to primary non-SI strains as well as to the molecularly cloned strains SF-162 and JR-CSF. Several primary SI strains, as well as the molecularly cloned dual-tropic viruses 89.6 and GUN-1, infected both Lestr+ and CCR5+ CCC/CD4 cells. Thus, these viruses can choose between Lestr and CCR5 for entry into cells. Interestingly, some dual-tropic primary SI strains that infected Lestr+ cells failed to infect CCR5+ cells, suggesting that these viruses may use an alternative coreceptor for infection of macrophages. Alternatively, CCR5 may be processed or presented differently on cat cells so that entry of some primary SI strains but not others is affected.
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PMID:Primary, syncytium-inducing human immunodeficiency virus type 1 isolates are dual-tropic and most can use either Lestr or CCR5 as coreceptors for virus entry. 897 Sep 55


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