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PubMed1992

Memory T lymphocyte hyporesponsiveness to non-cognate stimuli: a key factor in age-related immunodeficiency.

Previous studies from our laboratory have suggested that aging leads to an accumulation of cells expressing high levels of CD44, thought to be a marker for memory lymphocytes, and that positively selected CD44hi T cells, from mice of any age, respond poorly to concanavalin A (Con A) in limiting dilution estimates of interleukin (IL)-2-producing cells. We now report the results of a more comprehensive analysis of memory T cell function, in old and young mice, to non-cognate activators (Con A and the staphylococcal enterotoxin SEB). We report that memory T cells, isolated by removing cells bearing the CD45RB determinant, contain very few cells able to respond to either Con A or SEB under limiting dilution culture conditions, whether the responses are measured by IL-2 or by IL-3 accumulation. As a control, we show that memory T cells do respond strongly, at limiting dilution, to recently encountered priming antigens, i.e. Schistosoma mansoni egg antigen; the limiting dilution culture protocol thus does not preclude activation of memory T cells when cognate stimuli are presented to antigen-specific cells. These data suggest that virgin and memory T cells may differ fundamentally in their activation requirements, and suggest further that the accumulation, with age, of memory T cells accounts for the low responsiveness of old mice to non-cognate mitogens.

Aging↗

PubMedDate not supplied

Neuroendocrine tumors of the larynx.

A review of the international literature has revealed 68 paragangliomas, 42 large cell, and 74 small cell tumors of the larynx. Paragangliomas are usually benign, although malignant cases have been reported. Large cell tumors are malignancies associated with a high incidence of early cervical metastasis. Small cell tumors are aggressive cancers characterized by early, diffuse metastatic disease. All three neoplasms demonstrate a propensity for the supraglottic larynx. While surgery remains the treatment of choice for paragangliomas and large cell cancers, small cell cancers are best treated by radiotherapy and chemotherapy. The determinate 5-year survival for patients with paragangliomas, large cell, and small cell cancers is 60%, 34%, and 14%, respectively. While representing distinct clinical entities, these neoplasms demonstrate similar ultrastructural and histochemical features and should be classified as neuroendocrine tumors of the larynx (NETL). A comprehensive analysis of these laryngeal tumors is presented herein. Their clinical behavior and management options are reviewed and a scheme for their nomenclature and classification is proposed.

Adolescent↗

PubMed2025

Identification of Novel Wraparound Transcripts in JC Polyomavirus.

JC polyomavirus (JCPyV) is a ubiquitous pathogen that causes progressive multifocal leukoencephalopathy (PML). Although a recent study using next-generation sequencing (NGS) provided detailed transcriptome atlases for polyomaviruses (PyVs) such as BK polyomavirus and simian virus 40, the transcriptome of JCPyV remains poorly characterized. Here, we conducted a comprehensive analysis using both short-read and long-read NGS technologies to construct a transcriptome atlas of JCPyV. RNA extracted from IMR-32 and HEK293 cells transfected with the circular JCPyV genome was analyzed, leading to the identification of 39 previously uncharacterized viral transcripts in addition to 12 known ones. Among the novel transcripts, we identified wraparound transcripts, conserved across PyVs, which are generated through continuous, multicyclic transcription of the circular viral genome. These included both late transcripts containing leader-to-leader repeated sequences and SuperT transcripts with multiple LxCxE motifs. Notably, wraparound transcripts, including SuperT transcripts, were also detected in brain tissues from PML patients. Collectively, this study significantly expands our understanding of the JCPyV transcriptome, revealing the expression of wraparound transcripts in PML lesions. These findings provide valuable insights into the molecular basis of JCPyV gene expression and PML pathogenesis, potentially facilitating the development of effective countermeasures against PML.

JC Virus↗

PubMed1990

Incidence of regional lymph node metastasis in operable osteogenic sarcoma.

Records of 182 consecutive patients with the diagnosis of operable osteogenic sarcoma, treated between 1954 through 1980 by the Breast, Bone and Mixed Tumors Department of the Instituto Nacional de Enfermedades Neoplasicas (Lima, Peru), were reviewed to study the incidence of regional lymph node metastases in this disease. All the patients included in this study had radical surgery, which means the complete resection of the bone where the tumor is located, including the proximal joint, which permitted excision of the regional lymph nodes. Nineteen patients (10.4%) had evidence of sarcoma metastatic to draining lymph nodes. A comprehensive analysis of the literature shows that the incidence of metastasis to the lymph nodes in this study, is higher than those cited in a review of the literature, probably due to the policy in the management of osteogenic sarcoma in our institution, during the period of study.

Adolescent↗

PubMed1992

The microanatomy of canine islets of Langerhans: implications for intra-islet regulation.

In recent years models for the internal ("intra-islet") regulation of hormone secretion have been proposed to explain how different islet cells might regulate each other by means of their respective secretory peptides. Models that emphasize the importance of a directed intra-islet blood flow and sequence of perfusion of islet cells rely on a certain type of islet microanatomy and vascular supply. The experimental studies underlying these models have partly been performed in dogs. To extend the incomplete morphological knowledge of the canine endocrine pancreas both canine islets of Langerhans and extrainsular cells have been analysed in immunostained serial semithin (0.5 microns) sections. In addition to their occurrence within islets of Langerhans, all endocrine cell types are also found at extrainsular sites (about 9% of all endocrine cells) where they are distributed in different quantities among the epithelial lining of exocrine acini or excretory ducts and the connective tissue. There are continuous transitions from single extrainsular cells to small mono- and polycellular cell groups to islets. In a comprehensive analysis of whole islets, including computer-assisted three-dimensional reconstructions, the size, shape and vascularization of the islets as well as their cellular composition and the microtopology of islet cells have been studied. We have found marked intra- and inter-islet heterogeneities of the parameters investigated that are not compatible with concepts of a uniform and directed vascular perfusion of the various islet cell populations. Instead, their paracrine regulation may occur primarily via hormonal secretion into the intercellular spaces or vascular hormonal delivery to adjacent cells.

Animals↗

PubMed1979

Influence of age and of desmotropic drugs on the step phenomenon observed in rat skin.

Comprehensive analysis of the mechanical properties of rat skin revealed the "step phenomenon". This particular observation was made after constant strain rate (analysis of stress strain curves) as well as after constant load (creep experiments). Relative low extensions or low loads were necessary to provoke the steps. In most cases two, sometimes three steps were observed. The step phenomenon was found mainly in skin strips punched out perpendicularly to the body axis. Probably some bonds in the fibrous network are broken giving way to additional elongation whereafter stronger links take over the stress. Since earlier studies demonstrated a pronounced influence of age and of desmotropic drugs on mechanical properties at ultimate load, e.g., tensile strength, ultimate modulus of elasticity, and ultimate strain, also the step phenomenon was studied under these conditions. In stress-strain experiments most of the steps were found at the ages of 2 and 4 months. Total stress loss and total work loss due to the steps were the highest at the age of 4 months. If, however, these values were calculated as percentage of ultimate values, the highest figures were found in young animals. Elongation gain due to the steps also showed a maximum at time of maturation, e.g., 4 months. Similar findings were achieved in creep experiments at medium load (200 g). After treatment with prednisolone acetate more steps and after treatment with D-penicillamine fewer steps were observed. In stress-strain experiments total stress loss and total work loss due to steps were more than twice as high than controls after prednisolone treatment and only one half after D-penicillamine. If calculated as percentage of ultimate stress or percentage of work input, these changes disappeared because of similar changes at ultimate load. However, elongation gain due to steps, which was not significantly influenced by prednisolone acetate but significantly decreased by D-penicillamine, showed the same changes when calculated as percentage of ultimate strain. Under all conditions the step phenomenon mainly influenced the extension parameters. The data presented here confirm earlier observations that mechanical properties at low loads or low and medium extensions show at least to some extent a different pattern under the influence of maturation and age and after treatment with desmotropic drugs compared to the mechanical parameters at ultimate load.

Aging↗

PubMed1989

Age-related effect induced by oxidative stress on the cerebral glutathione system.

In the forebrain from male Wistar rats aged 5, 15 and 25 months, age-related putative alterations in the glutathione system (reduced and oxidized glutathione; redox index) were chronically induced by the administration in drinking water of free radical generators (hydrogen peroxide, ferrous chloride) or of inhibitors of endogenous free radical defenses (diethyl-dithio-carbamate, an inhibitor of superoxide dismutase activity). In hydrogen peroxide administered rats, both reduced glutathione and the cerebral glutathione redox index markedly declined as a function of aging, whereas oxidized glutathione consistently increased. In contrast, chronic iron intake failed to modify the reduced glutathione in forebrain from the rats of the different ages tested, whereas the oxidized glutathione was increased in the older brains. The chronic intake of diethyl-dithio-carbamate enhanced the concentrations of reduced glutathione in the forebrains from the rats of the different ages tested, the oxidized glutathione being unchanged. In 15-month-old rats submitted to chronic oxidative stress, ergot alkaloids (and particularly dihydroergocriptine) interfered with cerebral glutathione system, while papaverine was always ineffective. The comprehensive analysis of the data indicates that: (a) both the type of oxidative stress and the age of the animals modulate the cerebral responsiveness to the putative modifiers in the level of tissue free radicals; (b) aging magnifies the cerebral alterations induced by oxidative stress; the (c) cerebral glutathione system may be modified by metabolic rather than by circulatory interferences; (d) a balance between the various cerebral antioxidant defenses is present, the perturbation of an antioxidant system resulting in the compensatory modified activity of component(s) of another system.

Administration, Oral↗

PubMed1987

Laterobasal membranes from intestinal epithelial cells: isolation free of intracellular membrane contaminants.

A simplified method for isolating highly purified laterobasal membranes (LBM) from enterocytes is based on treatment of membranes with 8 mM CaCl2 concentration in order to aggregate intracellular membrane contaminants. The resultant LBM showed an average 15-fold enrichment and constituted 8% of the original K-stimulated phosphatase in the initial crude homogenate. It showed typical LBM migration on counter-current distribution (CCD) and was essentially free of contamination with endoplasmic reticulum and Golgi membranes. This method is highly efficient and yields sufficient purified LBM to allow comprehensive analysis of enterocyte membrane events.

Animals↗

PubMed1989

Evolution of the immunoglobulin heavy chain variable region (Igh-V) locus in the genus Mus.

The evolution of the mouse immunoglobulin heavy chain variable region (Igh-V) locus was investigated by the comprehensive analysis of variable region (Vh) gene family content and restriction fragment polymorphism in the genus Mus. The examination of natural Mus domesticus populations suggests an important role for recombination in the generation of the considerable restriction fragment polymorphism found at the Igh-V locus. Although the sizes of individual Vh gene families vary widely both within and between different Mus species, evolutionary trends of Vh gene family copy number are revealed by the analysis of homologues of mouse Vh gene families in Rattus and Peromyscus. Processes of duplication, deletion, and sequence divergence all contribute to the evolution of Vh gene copy number. Certain Vh gene families have expanded or contracted differently in the various muroid lineages examined. Collectively, these findings suggest that the evolution of individual Vh family size is not driven by strong selective pressure but is relatively neutral, and that gene flow, rather than selection, serves to maintain the high level of restriction fragment polymorphism seen in M. domesticus.

Animals↗

PubMed1992

Effect of 5-HT1A receptor agonists in two models of anxiety after dorsal raphe injection.

The purpose of the present study was two-fold. Firstly, to present a more comprehensive analysis of the disinhibitory effects of 5-HT1A receptor agonists after discrete dorsal raphe (DRN) injections (Higgins et al. 1988). Secondly, the effects of the 5-HT1B receptor agonist CGS12066B and the 5-HT1B/1C agonist mCPP were examined following injection into this nucleus. The increases in social interaction (SI) induced by intra-raphe injections of 8-OH DPAT (0.02-1 micrograms), buspirone (0.04-0.2 microgram), ipsapirone (0.2 microgram) and gepirone (0.2-1 micrograms) under a high light unfamiliar paradigm (HLU) were typically due to increased bout frequency, duration and a higher incidence of sniff, follow, allogroom behaviour. These increases were qualitatively similar to those seen in control animals tested under low light/familiar (LLF) conditions, thus supporting the belief that the drug-induced increases in SI reflected decreases in anxiety. Furthermore, at doses effective under the HLU condition, 8-OH DPAT, buspirone and gepirone failed to modify SI under conditions of minimal suppression (LLF paradigm). At doses which significantly increased punished responding in a water-lick conflict test 8-OH DPAT, ipsapirone and gepirone tended to also increase unpunished rates of drinking. However, in drug untreated rats, prior habituation to the test apparatus also increased unpunished drinking, suggesting some neophobia-induced suppression. At a comparatively high dose, the 5-HT1B agonist CGS12066B (2.5 micrograms), but not the putative 5-HT1B/1C agonist mCPP (0.5-12.5 micrograms), increased SI under the HLU condition.(ABSTRACT TRUNCATED AT 250 WORDS)

8-Hydroxy-2-(di-n-propylamino)tetralin↗

PubMed1987

Radiation doses in Europe after the Chernobyl accident.

In the course of the reactor accident at Chernobyl in 1986, large amounts of radioactive materials were released and spread over all of Europe and the rest of the world. A comprehensive analysis of the resulting radiation doses is still in progress through the United Nations Scientific Committee on the Effects of Atomic Radiations. This review lists the most significant nuclides involved and the most significant pathways of exposure. Preliminary estimates of radiation doses made by various organisations are presented. Particular emphasis is given to the collective effective dose equivalent which is important for the assessment of the possible future incidence of leukemia and cancer from the accident. This quantity amounted to about 200,000 mansievert for Europe outside of the Soviet Union, and about twice as much for the European part of the Soviet Union, for the first 50 years after the accident. The uncertainty in these estimates should be less than a factor of three up or down. According to the hypothesis of a linear dose-effect relationship this dose could be calculated to result in 6000 extra cases of cancer and hereditary disease, 4000 of which would be fatal, during 100 years in Europe outside the Soviet Union.

Accidents↗

PubMed2025

Bacteriophages as a modern diagnostic tool: innovations, applications and challenges.

Bacteriophages, viruses that specifically infect bacteria, have emerged as a valuable tool in diagnostics due to their unique specificity and adaptability. This review explores the diverse applications of bacteriophages in diagnostic methods, from traditional phage typing to advanced molecular techniques such as phage display and PCR-based diagnostics. It highlights their use in identifying bacterial strains, monitoring fermentation processes, and diagnosing critical conditions like tuberculosis, MRSA infections, and cancer. Innovations such as phage-based biosensors and reporter phages enhance the speed and precision of diagnostics, offering significant advantages over traditional methods. Challenges, including bacterial resistance and immune responses to phages, are also discussed alongside strategies for mitigation, such as phage cocktails and engineering. Integrating phage technology with modern bioscience holds promise for addressing antibiotic resistance and revolutionizing clinical and industrial diagnostics. This comprehensive analysis underscores the potential of bacteriophages to transform the diagnostic landscape while identifying areas requiring further research and development.

Bacteriophages↗

PubMed2026

The application of the CRISPR-Cas system in Pseudomonas aeruginosa infections.

Due to the extensive drug resistance of Pseudomonas aeruginosa (P. aeruginosa), it is still a great clinical challenge. The clustered regularly interspaced short palindromic repeats and associated proteins (CRISPR-Cas) system has become a promising strategy against this pathogen. This review critically evaluates the multifaceted applications of CRISPR-Cas technology in P. aeruginosa, including its role in antimicrobial resistance, diagnostics, genome editing, and emerging therapeutic and vaccine strategies. In addition to conducting a comprehensive analysis of various studies, we also compared the performance and limitations of various CRISPR platforms, and discussed the main technologies and transformation obstacles in this field. Finally, we look forward to the direction of applying these experimental tools to clinical research in the future.

Pseudomonas aeruginosa↗

PubMed2026

Genome-wide identification of CHY zinc finger and RING finger (CHYR) genes in pepper and functional characterization of CaCHYR5 in response to Phytophthora capsici infection.

CHY zinc finger and RING finger (CHYR) proteins play crucial roles in the growth and development, as well as stress response. To date, no systematic or comprehensive analysis of the CHYR gene family has been performed in pepper (Capsicum annuum L.). In this study, we identified 8 CaCHYR genes (CaCHYR1-CaCHYR8), which were classified into 3 groups based on phylogenetic relationships. CaCHYR members within the same group exhibited similar distributions of conserved motifs and exon-intron structures. Chromosomal localization analysis showed that 8 CaCHYR genes were unevenly distributed on 6 chromosomes. Segmental duplication, rather than tandem duplication, was found to be the major contributor to the expansion of this gene family. CaCHYR genes feature a variety of cis-elements involved in developmental processes, phytohormone responses, and stress adaptation. Expression analysis based on RNA-seq data revealed that CaCHYR genes exhibited distinct spatial expression patterns across different tissues and in response to Phytophthora capsici infection (PCI), and quantitative real-time PCR (qRT-PCR) further confirmed that three of them (CaCHYR2, CaCHYR3, and CaCHYR5) exhibited altered expression under PCI. Furthermore, transient overexpression of CaCHYR5 in pepper leaves increased susceptibility to PCI, suggesting its potential negative regulatory role in pepper defense against P. capsici. Collectively, these findings reveal the expression patterns and regulatory functions of pepper CHYR genes in growth and development, laying a groundwork for breeding pepper cultivars tolerant to PCI.

Phytophthora capsici infection (PCI)↗

PubMed1975

Mechanical performance of surgical sutures.

A comprehensive analysis of the mechanical performance of sutures has been made to provide information concerning the reliability and security of knotted sutures. The tests utilized in this analysis were designed to be easily reproduced by other investigators. The construction of the knot and the knot performance analysis were undertaken utilizing an Instron Tensile Tester. The mechanical reliability of each knotted suture was determined by measuring the number of throws to reach knot break, the expected slippage of the knot when it reaches knot break, and the maximal holding force at knot break. On the basis of these measurements, recommendations are made for the use of a suture at operation.

Biomechanical Phenomena↗

PubMed1990

Induction of haptotactic migration of melanoma cells by neutrophil activating protein/interleukin-8.

Natural or recombinant neutrophil activating cytokine (IL-8) induced migration across polycarbonate filters of human A 2058 melanoma cells. Anti-IL-8 antibodies blocked IL-8 induced melanoma cell migration. Checkerboard experiments revealed a gradient-dependent response of A2058 melanoma cells to IL-8. Filters exposed to IL-8 and washed supported melanoma cell migration, thus implying a haptotactic component in the response. The homologous polypeptide platelet factor 4 was inactive. The observation that IL-8 affects melanoma cells emphasizes the need for a comprehensive analysis of the spectrum of action of platelet factor 4-related peptides. The effect of the inflammatory cytokine IL-8 on melanoma cells may be relevant to augmented secondary localization of tumors at sites of inflammation.

Chemotactic Factors↗

PubMed1988

Mapping and sequencing of mutations in the Escherichia coli rpoB gene that lead to rifampicin resistance.

Rifampicin is an antibiotic that inhibits the function of RNA polymerase in eubacteria. Mutations affecting the beta subunit of RNA polymerase can confer resistance to rifampicin. A large number of rifampicin-resistant (hereafter called Rifr) mutants have been isolated in Escherichia coli to probe the involvement of RNA polymerase in a variety of physiological processes. We have undertaken a comprehensive analysis of Rifr mutations to identify their structural and functional effects on RNA polymerase. Forty-two Rifr isolates with a variety of phenotypes were mapped to defined intervals within the rpoB gene using a set of deletions of the rpoB gene. The mutations were sequenced. Seventeen mutational alterations affecting 14 amino acid residues were identified. These alleles are located in three distinct clusters in the center of the rpoB gene. We discuss the implications of our results with regards to the structure of the rifampicin binding site.

Base Sequence↗

PubMed1990

High-resolution three-dimensional structure of horse heart cytochrome c.

The 1.94 A resolution three-dimensional structure of oxidized horse heart cytochrome c has been elucidated and refined to a final R-factor of 0.17. This has allowed for a detailed assessment of the structural features of this protein, including the presence of secondary structure, hydrogen-bonding patterns and heme geometry. A comprehensive analysis of the structural differences between horse heart cytochrome c and those other eukaryotic cytochromes c for which high-resolution structures are available (yeast iso-1, tuna, rice) has also been completed. Significant conformational differences between these proteins occur in three regions and primarily involve residues 22 to 27, 41 to 43 and 56 to 57. The first of these variable regions is part of a surface beta-loop, whilst the latter two are located together adjacent to the heme group. This study also demonstrates that, in horse cytochrome c, the side-chain of Phe82 is positioned in a co-planar fashion next to the heme in a conformation comparable to that found in other cytochromes c. The positioning of this residue does not therefore appear to be oxidation-state-dependent. In total, five water molecules occupy conserved positions in the structures of horse heart, yeast iso-1, tuna and rice cytochromes c. Three of these are on the surface of the protein, serving to stabilize local polypeptide chain conformations. The remaining two are internally located. One of these mediates a charged interaction between the invariant residue Arg38 and a nearby heme propionate. The other is more centrally buried near the heme iron atom and is hydrogen bonded to the conserved residues Asn52, Tyr67 and Thr78. It is shown that this latter water molecule shifts in a consistent manner upon change in oxidation state if cytochrome c structures from various sources are compared. The conservation of this structural feature and its close proximity to the heme iron atom strongly implicate this internal water molecule as having a functional role in the mechanism of action of cytochrome c.

Amino Acid Sequence↗