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At least 1,225 records · Page 68Linked to original sources
PubMed2002

A role for C5a in augmenting IgG-dependent histamine release from basophils in chronic urticaria.

BACKGROUND: Histamine release in chronic urticaria is initiated by cross-linking of the alpha subunit of FcepsilonRI by means of IgG antibody, followed by complement activation. OBJECTIVE: We sought to further elucidate the mechanism by which complement augments histamine release and to assess the role of C5a. METHODS: We first quantitated the ability of purified C5a to initiate basophil histamine release and to be inhibited by antibody directed to the C5a receptor. Using this antibody, we quantitated its ability to inhibit histamine release induced by sera from patients with chronic urticaria. We also compared the ability of normal serum, C5-depleted serum, and C5-depleted serum after reconstitution with C5 to augment histamine release by IgG isolated from patients with chronic urticaria. RESULTS: As the concentration of C5a was increased up to 50 ng/mL, the percentage of histamine release increased and reached a plateau of 40% to 50%; this was inhibited by antibody to the C5a receptor. Preincubation of basophils with antibody to the C5a receptor inhibited basophil histamine release from 15 sera tested, with a range of 4% to 39%. Histamine release caused by patient IgG was augmented when normal serum was added but not when C5-depleted serum was substituted for normal serum. Augmentation of histamine release by patient IgG was again obtained when C5-depleted serum was reconstituted with C5. CONCLUSION: Our conclusion is that pathogenic IgG cross-links the IgE receptor directly to cause histamine release, and activation is augmented by complement. C5a is the complement agonist that is responsible for the augmented histamine release.

Basophils↗
PubMed2003

Quantitative trait locus analysis of leaf dissection in tomato using Lycopersicon pennellii segmental introgression lines.

Leaves are one of the most conspicuous and important organs of all seed plants. A fundamental source of morphological diversity in leaves is the degree to which the leaf is dissected by lobes and leaflets. We used publicly available segmental introgression lines to describe the quantitative trait loci (QTL) controlling the difference in leaf dissection seen between two tomato species, Lycopersicon esculentum and L. pennellii. We define eight morphological characteristics that comprise the mature tomato leaf and describe loci that affect each of these characters. We found 30 QTL that contribute one or more of these characters. Of these 30 QTL, 22 primarily affect leaf dissection and 8 primarily affect leaf size. On the basis of which characters are affected, four classes of loci emerge that affect leaf dissection. The majority of the QTL produce phenotypes intermediate to the two parent lines, while 5 QTL result in transgression with drastically increased dissection relative to both parent lines.

Genetic Complementation Test↗
PubMed1992

Interactions of synovial fluid immunoglobulins with chondrocytes.

OBJECTIVE: To study the interaction of synovial fluid (SF) immunoglobulins with living chondrocytes, and to evaluate the relative contribution of type II collagen (CII) antibodies. METHODS: SF of patients with rheumatoid arthritis (RA), osteoarthritis (OA), and gout were incubated with isolated bovine articular chondrocytes. Ig binding was measured by flow cytometry and by quantitation with 125I-labeled anti-IgG and anti-IgM. Complement-dependent cytotoxicity was determined by 51Cr release. Immunoglobulin binding and cytotoxicity were compared between chondrocytes obtained from the superficial and from the deep cartilage zones. RESULTS: Significantly greater IgG and IgM binding was found with RA SF compared with OA or gout SF. Chondrocytes bound more Ig than did fibroblasts. The relative contribution of anti-CII antibodies to Ig binding was studied following absorption of the SF with bovine CII, and by incubation with bacterial collagenase-treated chondrocytes. There was a small but significant reduction in IgG and IgM binding with SF samples that were positive for anti-CII. RA SF exhibited modest, but significantly greater complement-dependent cytotoxicity than OA SF: Gel chromatography fractionation indicated that IgM antibodies were responsible for the cytotoxic activity. Additional studies showed that SF IgM antibodies bound preferentially to, and killed chondrocytes obtained from, the superficial layers of cartilage. CONCLUSION: Anti-CII antibodies contained in RA SF represent one of many antibody specificities reacting with chondrocyte membrane antigens. Chondrocyte-reactive SF antibodies may play an important pathogenic role in the processes leading to irreversible cartilage damage in RA. These deleterious effects appear to be exerted particularly on chondrocytes located near the articular surface of cartilage.

Animals↗
PubMed1984

Characterization of anti-N-acetyl-D-glucosamine antibodies elicited through haptenated liposomes.

Antiserum was raised in rabbits against p-aminophenyl 2-acetamido-2-deoxy-beta-D-glucoside covalently coupled to phosphatidylaminoethanol-containing lecithin liposomes. The affinity-purified antibodies were found to be IgM. The properties of the antibodies were studied by ligand inhibition of quantitative precipitation, fluorescence titration with 2-acetamido-2-deoxy-D-glucose, and complement lysis of haptenated liposomes.

Acetylglucosamine↗
PubMed1996

Cell-type-specific modulation of PDGF-B regulatory elements via viral enhancer competition: a caveat for the use of reference plasmids in transient transfection assays.

The human platelet-derived growth factor-B (PDGF-B) gene has been shown to display a wide range of levels of mRNA transcription in a variety of cell types. Functional analyses of PDGF-B gene expression have begun to reveal intricate, cell-type-specific regulatory mechanisms involving multiple control elements. We have previously isolated and characterised several elements involved in the control of human PDGF-B gene expression in the JEG-3 choriocarcinoma cell line and in the breast cancer-derived cell line, ZR-75. Assessment of the positive or negative regulatory contributions of these elements was carried out using transient transfection assays. Such studies routinely require the inclusion of a reference plasmid in order to determine transfection efficiency. Here we show that competition for regulatory factors occurs in transfected cells between viral enhancers and elements regulating PDGF-B gene transcription. A frequently used reference plasmid which utilises the SV40 promoter and enhancer region to drive expression of a beta-galactosidase reporter gene was found to severely repress the activity of a co-transfected reporter construct containing the PDGF-B promoter and its intronic enhancer in JEG-3 cells. This competition was localised to the enhancer region of the SV40 regulatory sequences and surprisingly, the effect was reversed in ZR-75 cells; where increasing the amount of reference plasmid strongly stimulated the activity of the PDGF-B construct. These results imply that the same intronic region which functions equally well as an enhancer in two distinct cell-types, may operate in response to different transcription factor complements. Furthermore, this data demonstrates that the choice of reference plasmid and its quantitative use can be a crucial factor when examining putative regulatory elements by transient transfection methods.

Chloramphenicol O-Acetyltransferase↗
PubMed2004

Do T lymphocytes correlate danger signals to antigen?

When a cell is infected by a virus, or becomes transformed into a malignant state, it presents clues to its disease on the outer surface of its membrane. Such clues include peptide fragments of proteins produced inside the cell; when the cell is infected by a virus, viral peptides, as well as the cell's normal peptides, are displayed on the cell's membrane as potential antigens. Infected and malignant cells also externally present special molecules that ligate NKG2D receptors on immune cells. When patrolling T lymphocytes detect the presence of both their cognate peptide antigen and NKG2D ligands on one target, they proliferate and increasingly kill other cognate target cells. The danger model of immunity recognizes NKG2D ligands as stimulators of T cell cytotoxicity, but heretofore could not explain how T cells specific to normal peptides typical of healthy host cells outside the thymus, could avoid activation by danger signals on diseased cells. The problem is that T cells specific to host-peptides are also stimulated when those peptides are by chance also displayed on diseased cells displaying NKG2D ligands. However, if T cells predicated their cytotoxicity not only on the presence of their cognate antigen found in conjunction with danger signals, but also on the absence of their cognate antigen on cells not presenting danger signals, then only T cells specific for disease antigens would become activated. Since Fas display is correlated with viral or malignant transformation, it may be a danger-signal like NKG2D ligands. T cells which encounter Fas on malignant, cognate cells, increasingly bind Fas on healthy bystander cells not displaying cognate antigens. Perhaps such healthy bystander cells provide T cells with reference-levels of danger-signals for local tissue cells, allowing T cells to select between tolerance and cytotoxic reaction to their cognate antigen, as they circulate in the periphery. This paper will analyze cytotoxicity assays that show that T cells challenge syngeneic, non-cognate bystanders with Fas ligand (FasL), and why syngeny is a requirement for danger-reference cells. Some heretofore unexplained effects of superantigens will be suggested to be due to their obstruction of reference-target detection. This paper will also suggest that established tumors often evolve a subpopulation of high-danger-signal, low tumor-antigen cells that protect the tumor against T cells; that characteristics of dendritic cells (DC) complement the danger sensing of T cells; and that DC may also use quantitatively comparative, self-referential, danger-correlation measurements to recognize transformed cells interspersed among healthy host tissue cells.

Animals↗
PubMed1976

[Typing and detection of antibodies in the PLA system (platelet). Application to the study of neonatal thrombopenia by feto-maternal PLA allo-immunisation].

A platelet indirect radio-active Coombs test has been described. The technique for purification and labelling the antiglobulin has been precised. This test allows the typing of platelets in the PLA system and the study of sera from mothers of thrombocytopenic child. As examples, four families of neonatal thrombocytopenia are reported, with PLA1 negative mother. In the serum of three of these mothers, we could demonstrate anti-PLA antibodies in spite of a negative platelet complement fixation. This test has many advantages compared to other tests such as platelet complement fixation, assay for blocking antibodies or antiglobulin consumption: it gives objective and quantitative results and is highly reproducible, anticomplementary serum may be tested. It has enabled us to select PLA1 negative donors for exsanguino-transfusions of thrombocytopenic children born from PLA1 negative mothers.

Blood Platelets↗
PubMed2026

Seeing and Feeling DNA Methylation: Single-Molecule Biophysics Meets Machine Learning.

DNA methylation at 5-methylcytosine (5mC) is crucial for embryonic development and cellular function, while aberrant patterns strongly drive disease onset and progression. Its reversible nature offers substantial therapeutic potential, emphasizing the need for precise, context-specific genome wide 5mC mapping. Conventional techniques such as bisulfite sequencing and ensemble biosensor assays are hindered by DNA degradation, amplification bias, high cost, and inability to resolve single-molecule structural and mechanical effects of methylation. This review examines advances in single-molecule biophysical methods (nanopore sensing, smFRET, optical/magnetic tweezers, and AFM) that provide direct, label-free/minimally invasive 5mC detection, along with quantitative insights into DNA conformation, mechanics, and protein-DNA interactions. These techniques complement traditional methylome mapping by linking genomic localization to molecular mechanisms. Emerging machine-learning approaches are revolutionizing analysis, particularly in nanopore sensing, while promising applications in smFRET, tweezers, and AFM address throughput and reproducibility challenges. Their convergence promises scalable, high-resolution epigenetic profiling, advancing precision epigenomics toward clinical application.

DNA Methylation↗
PubMed1999

Bacteriologic and immunologic aspects of gram-negative folliculitis: a study of 46 patients.

BACKGROUND: Gram-negative folliculitis is an infection with gram-negative rods that most often occurs as a complication of prolonged broad-spectrum antibiotic therapy in patients suffering from acne and rosacea. METHODS: The bacteriologic and immunologic findings are reported in 46 patients, 39 men and 7 women, aged 16-79 (median, 28) years, with gram-negative folliculitis. Hypersensitivity reactions to various microbial recall antigens as well as granulocyte functions were evaluated. Quantitative measurements of serum levels of immunoglobulin M, G, A, and E, total complement activity, complement factors C3 and C4, and alpha-1-antitrypsin were performed. RESULTS: The gram-negative organisms most frequently cultivated from nares, facial skin, and pustules were Klebsiella spp., Escherichia coli, Enterobacter spp., and Proteus spp. In all patients, deviations of one or more immune parameters were detected, including lowered serum concentrations of immunoglobulin M and alpha-1-antitrypsin, and elevated levels of immunoglobulin E. The humoral and cellular parameters were not influenced by isotretinoin therapy of gram-negative folliculitis. CONCLUSIONS: These findings suggest that gram-negative folliculitis is not only a complication of long-lasting antibiotic treatment of acne and rosacea, but might be an entity of its own. Immunologic factors may play a critical role in the pathogenesis of gram-negative folliculitis.

Adolescent↗
PubMed1988

[Early and late results of heterotopic spleen autotransplantation in pediatric splenic trauma].

In this study, early and late results of heterotopic splenic autotransplantation in 18 children with type IV splenic injuries (Upadhyaya-Simpson classification) are presented. Splenic scintigrams, quantitative analysis of Howell-Jolly inclusion bodies, immunoglobulin (IgG, IgM, IgA) and complement C3 levels and T and B lymphocyte counts were analysed in the postoperative evaluation of the autotransplantation group. The total follow-up period was 7 years. According to our results, splenic implants increased complement C3 levels and improved filtration function of the splenectomized children. This autotransplantation group has two important characteristics: a) it is one of the largest series of the literature (pediatric age group), with b) longest follow-up period.

Adolescent↗
PubMed2006

Diagnostic value of voice acoustic analysis in assessment of occupational voice pathologies in teachers.

It has been shown that teachers are at risk of developing occupational dysphonia, which accounts for over 25% of all occupational diseases diagnosed in Poland. The most frequently used method of diagnosing voice diseases is videostroboscopy. However, to facilitate objective evaluation of voice efficiency as well as medical certification of occupational voice disorders, it is crucial to implement quantitative methods of voice assessment, particularly voice acoustic analysis. The aim of the study was to assess the results of acoustic analysis in 66 female teachers (aged 40-64 years), including 35 subjects with occupational voice pathologies (e.g., vocal nodules) and 31 subjects with functional dysphonia. The acoustic analysis was performed using the IRIS software, before and after a 30-minute vocal loading test. All participants were subjected also to laryngological and videostroboscopic examinations. After the vocal effort, the acoustic parameters displayed statistically significant abnormalities, mostly lowered fundamental frequency (Fo) and incorrect values of shimmer and noise to harmonic ratio. To conclude, quantitative voice acoustic analysis using the IRIS software seems to be an effective complement to voice examinations, which is particularly helpful in diagnosing occupational dysphonia.

Adult↗
PubMed2005

Phase noise in capacitively coupled micromechanical oscillators.

Phase noise in capacitively coupled microresonator-based oscillators is investigated. A detailed analysis of noise mixing mechanisms in the resonator is presented, and the capacitive transduction is shown to be the dominant mechanism for low-frequency 1/f-noise mixing into the carrier sidebands. Thus, the capacitively coupled micromechanical resonators are expected to be more prone to the 1/f-noise aliasing than piezoelectrically coupled resonators. The analytical work is complemented with simulations, and a highly efficient and accurate simulation method for a quantitative noise analysis in closed-loop oscillator applications is presented. Measured phase noise for a microresonator-based oscillator is found to agree with the developed analytical and simulated noise models.

Journal Article↗
PubMed1977

Cell loss from three established lines of the C3H mouse mammary tumor: a comparison of the 125I-UdR and the 3H-TdR-autoradiographic methods.

The 125I-UdR method for measuring cell loss from solid tumors has been reevaluated. The rate of tumor cell loss from three established lines (S 102F, S102S and Slow) of the C3H mouse mammary tumor was determined by the 125I-UdR method and the results were compared to the estimates for cell loss as determined by the combined approach of cellular 3H-TdR autoradiography and volumetric growth-rate determinations. This detailed comparison shows that the two methods complement each other but cannot substitute for one another because they give different quantitative information. The combined approach measures the flow of viable cells, as determined morphologically, from the proliferating compartment to the quiescent comparment, the quiescent compartment out of the tumor, etc., but does not evaluate the flow of degenerate cells or acellular (necrotic) debris. In contrast, the 125I-UdR method indicates the net flow of intact cells and/or dead cells as well as debris from the tumor as the 125I-labeled material is lost from the tumor, but gives limited internal information. thus, depending on the specific experiment, an investigator could choose one or the other of the methods to answer the question. Perhaps both would be desirable at times; however, in most cases, one could not substitute one method for the other. The data from the Slow tumors also indicate that in certain tumors, the quantitative information from the 125I-UdR method may be quite limited, i.e. the confidence limits within an experiment as well as the replication error between experiments may be high.

Animals↗
PubMed1975

Platelet indirect radioactive Coombs test. Its utilization for PLA1 grouping.

A platelet indirect radioactive Coombs test (PIRC) has been described. The technique for purification and labelling the antiglobulin has been precised. This test allowed the typing of platelets in the PLA system by using an absorbed serum from a mother of a thrombocytopenic child. Six other families of neonatal thrombocytopenias were tested. In three of them, the mothers were found PLA1 negative (PLA2, PLA2). Among a panel of 93 platelets, two (0.022) were found PLA1, negative. This PIRC test has many advantages compared to other tests such as platelet complement fixation, assay for blocking antibodies or antiglobulin consumption: it gives objective and quantitative results and is highly reproducible; anticomplementary serum may be tested.

Animals↗
PubMed1999

Involvement of the enteroaggregative Escherichia coli plasmid-encoded toxin in causing human intestinal damage.

Enteroaggregative Escherichia coli (EAEC) strains have been shown to adhere to human intestinal tissue in an in vitro organ culture (IVOC) model, and certain strains manifest mucosal toxicity. We have recently described the EAEC plasmid-encoded toxin (Pet), a member of a specific serine protease subclass of the autotransporter proteins. When injected into rat ileal loops, Pet both elicited fluid accumulation and had cytotoxic effects on the mucosa. Furthermore, the Pet protein caused rises in short circuit current from rat jejunal tissue mounted in a Ussing chamber and rounding of intestinal epithelial cells in culture. We therefore hypothesized that the mucosal pathology induced by EAEC strains in the IVOC model was related to expression of the Pet protein. Here, we have examined the effects of EAEC strain 042 and its isogenic pet mutant in the IVOC model. 042-infected colonic explants exhibited dilation of crypt openings, increased cell rounding, development of prominent intercrypt crevices, and absence of apical mucus plugs. Colonic tissue incubated with the pet mutant exhibited significantly fewer mucosal abnormalities both subjectively and as quantitated morphometrically by measurement of crypt aperture diameter. Mucosal effects were restored upon complementation of the pet mutation in trans. Interestingly, we found that the ability of 042 to damage T84 cells was not dependent upon Pet. The data suggest that the Pet toxin is active on the human intestinal mucosa but that EAEC may have other mechanisms of eliciting mucosal damage.

Cells, Cultured↗
PubMed2026

An overview of the DNA damage response in female reproductive system and breast cancers: A narrative review.

The DNA damage response (DDR) is a fundamental cellular network that preserves genomic integrity, and its dysregulation drives initiation, progression, and therapeutic response in female reproductive system and breast cancers. This narrative review provides a comparative analysis of DDR alterations across ovarian, endometrial, cervical, and breast cancers, synthesizing molecular studies, clinical trials, and international guidelines from PubMed/MEDLINE, Scopus, and Web of Science. DDR alterations vary substantially among these cancers, reflecting differences in tissue origin, hormonal regulation, and viral oncogenesis. Homologous recombination repair defects, particularly in breast cancer susceptibility 1/2, partner and localizer of BRCA2, ataxia telangiectasia mutated, and checkpoint kinase 2), are prevalent in ovarian, endometrial, and breast cancers, predicting sensitivity to platinum-based chemotherapy and poly (ADP-ribose) polymerase inhibitors. In endometrial cancer, homologous recombination deficiency predominates in high-grade tumor protein p53-mutated subtypes, while Fanconi anemia pathway alterations characterize aggressive serous carcinomas. Cervical cancer exhibits virus-induced DDR disruption and replication stress. Quantitative biomarkers, including tumor mutational burden, microsatellite instability, Radiation sensitive 51, Fanconi anemia complementation group D2, excision repair cross-complementation group 1, and DDR-related microRNAs enable patient stratification. Emerging ataxia telangiectasia and Rad3-related and WEE1 inhibitors show promise in combination regimens. Understanding of tumor-specific DDR enables rational therapeutic stratification, providing a framework for precision oncology.

DNA damage response, Ovarian neoplasms, Endometria↗
PubMed2006

Rickettsia prowazekii and real-time polymerase chain reaction.

Rickettsia prowazekii is the causative agent of epidemic typhus and a potential bioterrorism agent. Sensitive and specific rapid assays are needed to complement existing methods of detecting this organism. We developed a real-time quantitative polymerase chain reaction assay by using a species-specific probe targeting the gltA gene. This assay, which was rapid, specific for R. prowazekii only, and sensitive (cutoff detection of 1 to 5 copies per sample), detected and directly identified R. prowazekii in blood of 12 experimentally infected mice sampled at day 3 and 6 postinfection or in naturally or experimentally infected lice. Because our assay is highly standardized and easily adaptable, it could improve epidemic typhus surveillance in public health programs, especially for countries with underdiagnosed or unrecognized human cases.

Animals↗
PubMedDate not supplied

[Effects of age and body height on somatosensory evoked potentials].

The influence of age and height on somatosensory evoked potentials (SEP) following median and tibial nerve stimulation was studied. Age correlated with increase of latencies and decrease of amplitudes; exceptionally the amplitude of cortical N20 component increased with age. The central conduction time P31-P40 (tibial nerve stimulation) was longer in elderly subjects, whereas the time N13-N20 (median nerve stimulation) was independent of age. Height showed a positive correlation with latencies and peripheral conduction times; central conduction times (N13-N20 and P31-P40) were independent on height. The correlations of SEP parameters with age and height were expressed quantitatively by regression equations. The presented equations should be treated as a valuable complement to normative data in interpretation of SEP testing results.

Adult↗