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Shigella sonnei meningitis due to interleukin-1 receptor-associated kinase-4 deficiency: first association with a primary immune deficiency.

BACKGROUND: Inherited interleukin-1-receptor-associated kinase-4 (IRAK-4) deficiency is a recently described immunodeficiency associated with pyogenic bacterial infections and a poor inflammatory response. Shigella sonnei is generally associated with outbreaks of rectocolitis in developed countries, but systemic illnesses have occasionally been reported. An underlying primary immunodeficiency has not been found in such cases before now. METHODS: We report the clinical and immunological features of a patient with IRAK-4 deficiency who has a history of systemic shigellosis in addition to other infections. RESULTS: The patient has a history of Staphylococcus aureus, Streptococcus pneumoniae, and Pseudomonas aeruginosa infections during childhood and an episode of S. sonnei septicemia and meningitis at 10 years of age. This patient's history contrasted with that of other individuals infected concurrently by the same organism. Of note, these episodes were not accompanied by acute phase responses in our patient. Subsequently, the patient has had more episodes of staphylococcal disease, but no systemic illnesses. The patient is now 30 years old and has been doing well since prophylactic antibiotic treatment was stopped 4 years ago. DISCUSSION: To our knowledge, this is the first report of a case of systemic shigellosis in a person with a primary immunodeficiency, expanding the spectrum of infections associated with IRAK-4 deficiency. Thus, immunity mediated by IRAK-4 seems to be crucial for both the containment of and the inflammatory response to S. sonnei infection in the intestinal mucosa. IRAK-4 deficiency and related disorders should be considered in patients with systemic shigellosis.

Anti-Bacterial Agents↗

Role of T-cell-associated lymphocyte function-associated antigen-1 in the pathogenesis of experimental colitis.

The beta2 integrin lymphocyte function-associated antigen-1 (LFA-1; CD11a/CD18) is important for lymphocyte trafficking and activation as well as recruitment to sites of tissue inflammation. The objective of this study was to assess the role of 'T-cell-associated' LFA-1 in the pathogenesis of chronic colitis in vivo. Transfer of CD4+CD25- T cells isolated from wild-type (wt) mice into immunodeficient recipients [recombinase-activating gene-1-deficient (RAG-1-/-] produced moderate to severe colitis, whereas RAG-1-/- mice injected with CD11a-deficient (CD11a-/-; LFA-1-/-) donor T cells displayed minimal macroscopic and histological evidence of colitis. Surface expression of L-selectin, alpha4, alpha4beta7 and chemokine receptor-7 were similar for wt and CD11a-/- donor T cells. Attenuated disease in the CD11a-/- --> RAG-1-/- animals was associated with decreased numbers of CD4+ T cells in the mesenteric lymph nodes (MLNs), spleen and intestinal lamina propria (LP). In addition, significant reductions in Th1 cytokines were observed following ex vivo stimulation of mononuclear cells obtained from the MLNs and colonic LP. Interestingly, mononuclear cells obtained from the spleens of CD11a-/- --> RAG-1-/- exhibited enhanced pro-inflammatory cytokine production compared with splenocytes obtained from wt --> RAG-1-/- colitic mice. Taken together, our data suggest that T-cell-associated CD11a (LFA-1) expression plays a dual role in the initiation of chronic gut inflammation by facilitating naive T-cell priming/activation and expansion within MLNs and by augmenting pro-inflammatory cytokine production following secondary stimulation by antigen-presenting cells in the colonic interstitium.

Animals↗

Epstein-Barr virus encoded latent membrane protein 1 (LMP1) and TNF receptor associated factors (TRAF): colocalisation of LMP1 and TRAF1 in primary EBV infection and in EBV associated Hodgkin lymphoma.

AIMS: Epstein-Barr virus (EBV) immortalises B cells in vitro and is associated with several malignancies. Most phenotypic effects of EBV are mediated by latent membrane protein 1 (LMP1), which interacts with tumour necrosis factor receptor associated factors (TRAFs) to activate NF-kappaB. This study examines TRAF1 and LMP1 expression in EBV associated lymphoproliferations. METHODS: TRAF1 expression was investigated in 26 Hodgkin lymphomas (HL; 18 EBV+, eight EBV-), seven EBV+ Burkitt lymphomas (BL), two infectious mononucleosis (IM) tonsils, and lymphoreticular tissue from eight chronic virus carriers. Seven anaplastic large cell lymphomas and 10 follicular B cell lymphomas were also studied. Colocalisation of TRAF1 and LMP1 was studied by immunofluorescent double labelling and confocal laser microscopy. RESULTS: TRAF1 colocalises with LMP1 in EBV infected cells in IM. EBV positive lymphocytes from chronic virus carriers were negative for TRAF1 and LMP1. In HL biopsies, TRAF1 was strongly expressed independently of EBV status, whereas all BL cases were TRAF1-. In EBV+ HL cases, TRAF1 colocalised with LMP1. Eight of 10 follicular lymphomas expressed TRAF1 in centroblast-like cells. Four of seven anaplastic large cell lymphomas weakly expressed TRAF1. CONCLUSIONS: These results suggest that in non-neoplastic lymphocytes, TRAF1 expression is dependent on the presence of LMP1, and that in IM B cells in vivo, LMP1 associated signalling pathways are active. In HL, TRAF1 is expressed independently of EBV status, probably because of constitutive NF-kappaB activation. The function of TRAF1 in HL remains to be determined.

Carrier State↗

Surface association of pregnancy-associated plasma protein-A accounts for its colocalization with activated macrophages.

Intense immunostaining for pregnancy-associated plasma protein-A (PAPP-A), a newly characterized metalloproteinase in the insulin-like growth factor system, colocalizes with activated macrophages in human atherosclerotic plaque. To determine macrophage regulation of PAPP-A expression, we developed two models of human macrophages with basal and activated phenotypes. THP-1 cells and peripheral blood monocytes could be differentiated into macrophages and activated upon specific treatment regimens with phorbol myristate acetate, macrophage colony-stimulating factor, and interleukin-1beta. Activation was assessed by cell secretion of tumor necrosis factor-alpha, which increased 30- to 100-fold with activation. Activated macrophages also secreted matrix metalloproteinase-9. However, no PAPP-A mRNA or PAPP-A antigen could be detected in these cells under any condition. Upon incubation with recombinant PAPP-A, we found that activated macrophages bound and internalized more PAPP-A than unactivated macrophages or monocytes. Internalization accounted for at least 50% of macrophage-associated PAPP-A, as assessed in studies with cytochalasin B. Membrane-bound PAPP-A retained protease activity, whereas internalized PAPP-A had little or no activity. Similar experiments carried out with a mutated variant of PAPP-A, which retains functionality as a protease but is unable to bind surface-associated glycosaminoglycan, showed no macrophage association or internalization. Absence of PAPP-A expression was confirmed in activated macrophages isolated from a hypercholesterolemic rabbit model of atherosclerosis. We therefore conclude that PAPP-A is not synthesized in, but rather is bound and internalized by, macrophages. Our findings likely account for the observed intense immunostaining for PAPP-A colocalizing with activated macrophages and may have physiological significance in the development of vulnerable plaque.

Animals↗

In vitro associative conditioning of Hermissenda: cumulative depolarization of type B photoreceptors and short-term associative behavioral changes.

Cumulative depolarization of Hermissenda type B photoreceptors, a short-term neural correlate of associative learning, was produced by simulating associative training in the isolated nervous system (in vitro conditioning). This simulation entailed stimulation and recording from three classes of neurons normally affected by the associative training procedure: a type B photoreceptor, the silent/excitatory (S/E) optic ganglion cell, and a statocyst caudal hair cell. Exposure of the isolated nervous system to five simultaneous pairings of light and current-induced impulse activity of the caudal hair cell resulted in an average 10-mV depolarization of type B cells. Cumulative depolarization was found to be pairing specific, to occur with a minimal number of training trials, and was paralleled by short-term pairing-specific changes in phototactic behavior for the intact animal. Two important determinants of cumulative depolarization were found to be the magnitude and duration of the long-lasting depolarization (LLD) response of type B cells to light, and a pairing-specific synaptic facilitation of the LLD response. The synaptic facilitation arose from two distinct sources: increased excitatory postsynaptic potential (EPSP) feedback on B cells following light and caudal hair cell stimulation pairings, and disinhibition of the type B photoreceptor following pairings. The S/E optic ganglion cell was found to be a potent regulator of B cell EPSPs. Cumulative depolarization was substantially reduced when the S/E cell was hyperpolarized throughout the course of pairings. Conversely, pairings of light with depolarizing current stimulation of the S/E cell were sufficient to produce cumulative depolarization of B cells. Precluding disinhibition of the B cell from the caudal hair cell was also found to attenuate cumulative depolarization. Additional constraints, inherent to the neural organization of the visual and statocyst neural systems were found to further limit the degree of cumulative depolarization. Among the most important of these were the interpairing interval and light intensity. Exposure of intact animals of five pairings of light and rotation resulted in short-term suppression of phototactic behavior. Like the cumulative depolarization of B cells with in vitro conditioning procedures, these changes were relatively pairing specific and persisted for comparable durations of time. Cumulative depolarization of B cells appears to be an important initial step in the production of long-term associative neural and behavioral changes in Hermissenda.

Animals↗

Neuronal damage and plasticity identified by microtubule-associated protein 2, growth-associated protein 43, and cyclin D1 immunoreactivity after focal cerebral ischemia in rats.

BACKGROUND AND PURPOSE: An objective of therapeutic intervention after cerebral ischemia is to promote improved functional outcome. Improved outcome may be associated with a reduction of the volume of cerebral infarction and the promotion of cerebral plasticity. In the developing brain, neuronal growth is concomitant with expression of particular proteins, including microtubule-associated protein 2 (MAP-2), growth-associated protein 43 (GAP-43), and cyclin D1. In the present study we measured the expression of select proteins associated with neurite damage and plasticity (MAP-2 and GAP-43) as well as cell cycle (cyclin D1) after induction of focal cerebral ischemia in the rat. METHODS: Brains from rats (n=28) subjected to 2 hours of middle cerebral artery occlusion and 6 hours, 12 hours, and 2, 7, 14, 21, and 28 days (n=4 per time point) of reperfusion and control sham-operated (n=3) and normal (n=2) rats were processed by immunohistochemistry with antibodies raised against MAP-2, GAP-43, and cyclin D1. Double staining of these proteins for cellular colocalization was also performed. RESULTS: Loss of immunoreactivity of both MAP-2 and GAP-43 was observed in most damaged neurons in the ischemic core. In contrast, MAP-2, GAP-43, and cyclin D1 were selectively increased in morphologically intact or altered neurons localized to the ischemic core at an early stage (eg, 6 hours) of reperfusion and in the boundary zone to the ischemic core (penumbra) during longer reperfusion times. CONCLUSIONS: The selective expressions of the neuronal structural proteins (MAP-2 in dendrites and GAP-43 in axons) and the cyclin D1 cell cycle protein in neurons observed in the boundary zone to the ischemic core are suggestive of compensatory and repair mechanisms in ischemia-damaged neurons after transient focal cerebral ischemia.

Animals↗

Characterization of the intermolecular associations of the dystrophin-associated glycoprotein complex in retinal Müller glial cells.

The abnormal retinal neurotransmission observed in Duchenne muscular dystrophy patients has been attributed to altered expression of C-terminal products of the dystrophin gene in this tissue. Müller glial cells from rat retina express dystrophin protein Dp71, utrophin and the members of the dystrophin-associated glycoprotein complex (DGC), namely beta-dystroglycan, delta- and gamma-sarcoglycans and alpha1-syntrophin. The DGC could function in muscle as a link between the cystoskeleton and the extracellular matrix, as well as a signaling complex. However, other than in muscle the composition and intermolecular associations among members of the DGC are still unknown. Here we demonstrate that Dp71 and/or utrophin from rat retinal Müller glial cells form a complex with beta-dystroglycan, delta-sarcoglycan and alpha1-syntrophin. We also show that beta-dystroglycan is associated with alpha-dystrobrevin-1 and PSD-93 and that anti-PSD antibodies coimmunoprecipitated alpha-syntrophin with PSD-93. By overlay experiments we also found that Dp71and/or utrophin and alpha-dystroglycan from Müller cells could bind to actin and laminin, respectively. These results indicate that the DGC could have both structural and signaling functions in retina. On the basis of our accumulated evidence, we propose a hypothetical model for the molecular organization of the dystrophin-associated glycoprotein complex in retinal Müller glial cells, which would be helpful for understanding its function in the central nervous system.

Actins↗

Interaction properties of human mannan-binding lectin (MBL)-associated serine proteases-1 and -2, MBL-associated protein 19, and MBL.

The mannan-binding lectin (MBL) activation pathway of complement plays an important role in the innate immune defense against pathogenic microorganisms. In human serum, two MBL-associated serine proteases (MASP-1, MASP-2) and MBL-associated protein 19 (MAp19) were found to be associated with MBL. With a view to investigate the interaction properties of these proteins, human MASP-1, MASP-2, MAp19, as well as the N-terminal complement subcomponents C1r/C1s, Uegf, and bone morphogenetic protein-1-epidermal growth factor (CUB-EGF) segments of MASP-1 and MASP-2, were expressed in insect or human kidney cells, and MBL was isolated from human serum. Sedimentation velocity analysis indicated that the MASP-1 and MASP-2 CUB-EGF segments and the homologous protein MAp19 all behaved as homodimers (2.8-3.2 S) in the presence of Ca(2+). Although the latter two dimers were not dissociated by EDTA, their physical properties were affected. In contrast, the MASP-1 CUB-EGF homodimer was not sensitive to EDTA. The three proteins and full-length MASP-1 and MASP-2 showed no interaction with each other as judged by gel filtration and surface plasmon resonance spectroscopy. Using the latter technique, MASP-1, MASP-2, their CUB-EGF segments, and MAp19 were each shown to bind to immobilized MBL, with K:(D) values of 0.8 nM (MASP-2), 1.4 nM (MASP-1), 13.0 nM (MAp19 and MASP-2 CUB-EGF), and 25.7 nM (MASP-1 CUB-EGF). The binding was Ca(2+)-dependent and fully sensitive to EDTA in all cases. These data indicate that MASP-1, MASP-2, and MAp19 each associate as homodimers, and individually form Ca(2+)-dependent complexes with MBL through the CUB-EGF pair of each protein. This suggests that distinct MBL/MASP complexes may be involved in the activation or regulation of the MBL pathway.

Amino Acid Motifs↗

Promoter hypermethylation of Death-associated protein-kinase gene associated with advance stage gastric cancer.

Death-associated protein kinase (DAP-kinase) is a serine/threonine kinase and a positive mediator of apoptosis. Down-regulation of DAP-kinase was associated with increased metastatic potential of tumors. Gene promoter hypermethylation could lead to down-regulation of DAP-kinase. We aimed to investigate the frequency of gene promoter methylation of DAP-kinase in gastric carcinoma (GCA) and assessed its association with clinicopathological features. One hundred and seven cases of gastric carcinoma were examined. The relevant clinical and pathological features, including survival data were reviewed. Methylation status was assessed by methylation-specific PCR (MSP). Seventy-four cases (69.2%) of GCA demonstrated promoter methylation of DAP-kinase. Methylation of DAP-kinase was observed in intestinal, diffuse and mixed type of GCA. It also occurred in similar frequency among antral, body and cardiac gastric cancer. No association between methylation status and age or gender was demonstrated. However, the methylated cases correlated with the presence of nodal metastasis (p=0.041), advance stage of disease (p=0.029) and a poorer event-free survival (log-rank test p=0.0141). DAP-kinase promoter methylation as a potential prognostic marker for gastric cancer patients deserved further evaluation.

Apoptosis Regulatory Proteins↗

Disconnection of the amygdala from visual association cortex impairs visual reward-association learning in monkeys.

Cynomolgus monkeys (Macaca fascicularis) were trained in a task that assessed their ability to associate visual stimuli with food reward. Acquisition of stimulus-reward associations was measured under 2 conditions, a 2-stimuli acquisition condition and a 1-stimulus acquisition condition. On each trial in the 2-stimuli condition, the positive (correct) and negative (incorrect) stimuli were presented side by side and the animal chose one by touching it; if the choice was correct, a food reward was dispensed. On each trial in the 1-stimulus condition, either the positive or the negative stimulus was presented alone; if the stimulus was the positive, it was followed by reward delivery, regardless of the animal's response to it, and if it was the negative, it was not followed by reward delivery. Thus, reward delivery was contingent upon the animal's response to the stimuli in the 2-stimuli condition but not in the 1-stimulus condition. The effect of acquisition trials under these 2 conditions was measured, in both conditions, by the animal's subsequent choice when presented with the 2 stimuli side by side. Following preoperative training in this task, the animals were first subjected to unilateral ablation of the inferotemporal cortex. This operation had little effect on the animals' learning ability. Then, the amygdala was ablated in the hemisphere contralateral to that in which the unilateral inferotemporal ablation had been carried out. This combination of crossed unilateral lesions of the amygdala and of the inferotemporal cortex, which disconnects the amygdala from the output of visual association cortex, produced a profound impairment in stimulus-reward-associative learning.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗

Three who made an association: I. Sir William Osler, 1849-1919 II. George Milbry Gould, 1848-1922 III. Margaret Ridley Charlton, 1858-1931 and the founding of the Medical Library Association, Philadelphia, 1898.

The careers and personalities of the three founders of the Medical Library Association, Sir William Osler, George Milbry Gould, and Margaret Ridley Charlton are outlined, followed by a review of their role in the founding of the association. The career of Sir William Osler is well documented in existing literature, both in medical history and medical librarianship; the biographies of George Milbry Gould and Margaret Ridley Charlton are less known, and this article describes their lives in relation to the founding of the association. The issue of responsibility for the association's founding is explored, and primary recognition is attributed to Margaret Charlton. The author attempts to follow the tradition of Harvey Cushing in his The Life of Sir William Osler in allowing the characters to speak in their own words as much as possible.

Canada↗

Three who made an association: I. Sir William Osler, 1849-1919. II. George Milbry Gould, 1848-1922. III. Margaret Ridley Charlton, 1858-1931 and the founding of the Medical Library Association, Philadelphia, 1898.

The careers and personalities of the three founders of the Medical Library Association, Sir William Osler, George Milbry Gould, and Margaret Ridley Charlton are outlined, followed by a review of their role in the founding of the association. The career of Sir William Osler is well documented in existing literature, both in medical history and medical librarianship; the biographies of George Milbry Gould and Margaret Ridley Charlton are less known, and this article describes their lives in relation to the founding of the association. The issue of responsibility for the association's founding is explored, and primary recognition is attributed to Margaret Charlton. The author attempts to follow the tradition of Harvey Cushing in his The Life of Sir William Osler in allowing the characters to speak in their own words as much as possible.

Canada↗

TNF receptor family member BCMA (B cell maturation) associates with TNF receptor-associated factor (TRAF) 1, TRAF2, and TRAF3 and activates NF-kappa B, elk-1, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinase.

BCMA (B cell maturation) is a nonglycosylated integral membrane type I protein that is preferentially expressed in mature B lymphocytes. Previously, we reported in a human malignant myeloma cell line that BCMA is not primarily present on the cell surface but lies in a perinuclear structure that partially overlaps the Golgi apparatus. We now show that in transiently or stably transfected cells, BCMA is located on the cell surface, as well as in a perinulear Golgi-like structure. We also show that overexpression of BCMA in 293 cells activates NF-kappa B, Elk-1, the c-Jun N-terminal kinase, and the p38 mitogen-activated protein kinase. Coimmunoprecipitation experiments performed in transfected cells showed that BCMA associates with TNFR-associated factor (TRAF) 1, TRAF2, and TRAF3 adaptor proteins. Analysis of deletion mutants of the intracytoplasmic tail of BCMA showed that the 25-aa protein segment, from position 119 to 143, conserved between mouse and human BCMA, is essential for its association with the TRAFs and the activation of NF-kappa B, Elk-1, and c-Jun N-terminal kinase. BCMA belongs structurally to the TNFR family. Its unique TNFR motif corresponds to a variant motif present in the fourth repeat of the TNFRI molecule. This study confirms that BCMA is a functional member of the TNFR superfamily. Furthermore, as BCMA is lacking a "death domain" and its overexpression activates NF-kappa B and c-Jun N-terminal kinase, we can reasonably hypothesize that upon binding of its corresponding ligand BCMA transduces signals for cell survival and proliferation.

Amino Acid Sequence↗

Ocular characteristics and disease associations in scleritis-associated peripheral keratopathy.

OBJECTIVES: To evaluate ocular characteristics and systemic disease associations in patients with scleritis-associated peripheral keratopathy and its different patterns, and to assess any ocular or systemic prognostic significance of the presence of the types of peripheral keratopathy in patients with scleritis. DESIGN: Review of 125 patients with scleritis alone and 47 patients with scleritis-associated peripheral keratopathy; review of patients with scleritis and the different patterns of peripheral keratopathy: peripheral corneal thinning, stromal keratitis, and peripheral ulcerative keratitis (PUK); review of ocular and systemic outcomes comparisons between patients with scleritis with and without peripheral keratopathy. RESULTS: Patients with peripheral keratopathy had more necrotizing scleritis (57%, P<.001), decrease in vision (81%, P<.001), anterior uveitis (62%, P<.002), impending corneal perforation (62%, P<.001), and potentially lethal specific-disease association (87%, P<.001) than did patients with scleritis alone. Patients with PUK had the worst ocular and systemic outcomes. Of the 24 patients with PUK, 16 (67%) had necrotizing scleritis (P =.02), virtually all had a potentially lethal systemic disease (P =.02), and all had impending corneal perforation (P<.001). CONCLUSION: The detection of peripheral keratopathy, and especially PUK, in a patient with scleritis indicates a poor ocular and systemic prognosis.

Adolescent↗

The association between cell proliferation and apoptosis: studies using the cell cycle-associated proteins Ki67 and DNA polymerase alpha.

The process of apoptosis is associated with the inappropriate expression of cell cycle regulatory proteins, which has led to the proposal that the apoptotic pathway represents an abortive attempt to pass through the cell proliferation cycle. To investigate this hypothesis, we examined the expression of two proliferation-associated antigens in apoptotic cells. Apoptotic bodies seen in a range of normal and pathological tissues are often positive for the Ki67 antigen, indicating that these cells were in the cell cycle during the period that they died. In contrast, spontaneous apoptosis of human polymorphonuclear leukocytes maintained in culture was not associated with the expression of either Ki67 or DNA polymerase a. In addition, apoptotic bodies in the pre-menstrual endometrium did not express the Ki67 antigen. These results indicate that, contrary to previous suggestions, apoptosis does not always depend on cell cycle entry. The use of antibodies to Ki67 should be valuable in defining the association of apoptosis with proliferation in a wide range of cells and tissues.

Apoptosis↗

Association of the inflammatory state in active juvenile rheumatoid arthritis with hypo-high-density lipoproteinemia and reduced lipoprotein-associated platelet-activating factor acetylhydrolase activity.

OBJECTIVE: To investigate the relationship between the quantitative and qualitative abnormalities of apolipoprotein B (Apo B)- and Apo A-I-containing lipoproteins and between lipoprotein-associated platelet-activating factor acetylhydrolase (PAF-AH) activity in patients with juvenile rheumatoid arthritis (JRA) as a function of the inflammatory state. METHODS: Twenty-six JRA patients and 22 age- and sex-matched control subjects with normal lipid levels participated in the study. Fourteen patients had active disease, and 12 had inactive disease. Plasma lipoproteins were fractionated by gradient ultracentrifugation into 9 subfractions, and their chemical composition and mass were determined. The PAF-AH activity associated with lipoprotein subfractions and the activity in plasma were also measured. RESULTS: Patients with active JRA had significantly lower plasma total cholesterol and high-density lipoprotein (HDL) cholesterol levels as compared with controls, due to the decrease in the mass of both the HDL2 and HDL3 subfractions. Patients with active JRA also had higher plasma triglyceride levels, mainly due to the higher triglyceride content of the very low-density lipoprotein plus the intermediate-density lipoprotein subfraction. The plasma PAF-AH activity in patients with active JRA was lower than that in controls, mainly due to the decrease in PAF-AH activity associated with the intermediate and dense low-density lipoprotein subclasses. The lipid abnormalities and the reduction in plasma PAF-AH activity were significantly correlated with plasma C-reactive protein levels and were not observed in patients with inactive JRA. CONCLUSION: This is the first study to show that patients with active JRA exhibit low levels of HDL2 and HDL3 and are deficient in plasma PAF-AH activity. These alterations suggest that active JRA is associated with partial loss of the antiinflammatory activity of plasma Apo B- and Apo A-I-containing lipoproteins.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗

Tracheal agenesis and associated malformations: a comparison with tracheoesophageal fistula and the VACTERL association.

Tracheal agenesis is a rare malformation of the lower respiratory tract. Investigation of a patient with multiple congenital anomalies and tracheal agenesis prompted a review of the literature which uncovered 42 previously published cases, most of whom had other defects. The presence in our patient of a tracheal abnormality in association with radial hypoplasia, single umbilical artery, tetralogy of Fallot, and left hydroureter initially suggested presence of the VACTERL association. However, numerical classification of malformation patterns in the reported patients with tracheal agenesis and in a series of patients with tracheoesophageal fistula and other components of the VACTERL association suggests that tracheal agenesis does not occur in the VACTERL association and may be part of another pattern of malformations which includes laryngeal atresia, complex congenital heart anomalies, radial ray defects, and duodenal atresia.

Abnormalities, Multiple↗

Modeling of tumor necrosis factor receptor superfamily 1A mutants associated with tumor necrosis factor receptor-associated periodic syndrome indicates misfolding consistent with abnormal function.

OBJECTIVE: To investigate the effect of mutations in the tumor necrosis factor receptor superfamily 1A (TNFRSF1A) gene on the conformation and behavior of the TNFRSF1A protein. Mutations in TNFRSF1A cause the autosomal-dominant, autoinflammatory TNFR-associated periodic syndrome (TRAPS). METHODS: The expression of recombinant TNFRSF1A was compared in SK-HEp-1 endothelial cells and HEK 293 epithelial cells stably transfected with full-length R347A or Deltasig constructs of wild-type or TRAPS-associated mutant TNFRSF1A. TNF binding was assessed in HEK 293 cell lines expressing R347A wild-type or mutant TNFRSF1A. Homology modeling of the 3-dimensional structure of the ectodomains of wild-type and mutant TNFRSF1A was performed. RESULTS: TRAPS-associated mutant and wild-type TNFRSF1A behaved differently and had different localization properties within the cell, as a direct result of mutations in the ectodomains of TNFRSF1A. From a structural perspective, mutants with a predicted structure similar to that of the wild-type protein (e.g., R92Q) behaved similarly to wild-type TNFRSF1A, whereas forms of TNFRSF1A with mutations predicted to drastically destabilize the protein structure (e.g., cysteine mutations) showed defects in cell surface expression and TNF binding. CONCLUSION: The results obtained from the in vitro experiments, in combination with the modeled structures, indicate that the phenotype and clinical differences between different TRAPS-associated mutants of TNFRSF1A result from different conformations of the TNFRSF1A ectodomains.

Carcinoma, Hepatocellular↗