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Biomedical subjects

J Eldridge

Publications and source records attributed to J Eldridge.

At least 19 recordsLinked to original sources

Liver function and morphology after resuscitation from severe hemorrhagic shock with hemoglobin solutions or autologous blood.

OBJECTIVE: To test the effects of three hemoglobin solutions on liver function and hepatic morphology after resuscitation from severe hemorrhagic shock. DESIGN: Prospective study. SETTING: Laboratory. SUBJECTS: Thirty-three beagle dogs. INTERVENTION: Hemorrhagic shock was induced in anesthetized dogs by removal of blood at a rate of 2 mL/kg/min until systolic blood pressure (BP) reached 50 mm Hg. BP was maintained at this level 2 hrs by further withdrawing 5 to 10 mL aliquots whenever BP increased > 50 mm Hg. Resuscitation was then initiated with autologous whole blood (n = 7), 4% pyridoxalated-hemoglobin-polyoxyethylene conjugate (4% PHP [n = 6]), 8% pyridoxalated-hemoglobin-polyoxyethylene conjugate (8% PHP [n = 9], or 8% stroma-free hemoglobin (n = 7). Four dogs were managed identically but were not resuscitated. Gross necropsy and histologic examination of the liver were performed on all dogs after 7 days, or earlier if death occurred. MEASUREMENTS AND MAIN RESULTS: In vitro interferences of PHP and stroma-free hemoglobin with liver function tests were determined and recommendations for interpretation of results from blood samples containing PHP and stroma-free hemoglobin were made. Blood was collected before, during, and after resuscitation from hemorrhagic shock. The dogs were then awakened and survivors were monitored daily with blood sampling until they were killed and necropsy was performed. After 7 days, the survival rate following hemorrhagic shock was 100% for whole blood and 4% PHP, 86% for stroma-free hemoglobin, and 33% for 8% PHP. Of the resuscitated dogs not surviving 7 days, all but one died within 27 hrs from coagulopathy. All dogs not resuscitated died within 1.75 hrs after 2 hrs of shock. Bilirubin, alkaline phosphatase, and lactic dehydrogenase concentrations could not be measured due to interferences of stroma-free hemoglobin and PHP. Aspartate (AST) and alanine (ALT) aminotransferase concentrations could be measured after dilution to overcome the interferences. Significant increases in AST and ALT values in all groups 24 hrs after resuscitation were attributed to hypoxic hepatocellular damage associated with the severity of the shock model rather than to the resuscitation fluid. Liver histology showed no changes attributed to toxic damage of hepatocytes in dogs resuscitated with stroma-free hemoglobin or PHP. However, changes, were less severe in dogs resuscitated with 4% PHP than in other groups. CONCLUSION: Morphologic studies at necropsy and liver function tests in dogs receiving hemoglobin solutions, compared with autologous blood, support the conclusion that the PHP and stroma-free hemoglobin solutions tested did not produce hepatic toxicity when used as resuscitation fluids in this model of severe shock.

Acute Disease

Evaluation of purified UspA from Moraxella catarrhalis as a vaccine in a murine model after active immunization.

Moraxella catarrhalis causes otitis media, laryngitis, and respiratory infections in humans. A high-molecular-weight outer membrane protein from this bacterium named ubiquitous surface protein A (UspA) is present on all isolates. A monoclonal antibody (MAb) to UspA that recognizes a conserved epitope of this protein has been shown to promote pulmonary clearance of bacteria in passively immunized mice. In the present study, M. catarrhalis heterologous isolates were screened by dot blot with a panel of four additional MAbs specific for surface-exposed epitopes of UspA from M. catarrhalis isolate 035E. Three of the MAbs were specific for 035E, and the fourth reacted with 17 (74%) of the 23 isolates tested. Thus, UspA contains highly conserved, semiconserved, and variable surface-exposed epitopes. The UspA was purified from the 035E isolate by ion-exchange and size-exclusion chromatography, formulated with the adjuvant QS-21, and used to immunize BALB/c mice. Upon pulmonary challenge with either 035E or the heterologous isolate TTA24, significantly fewer bacteria were recovered from the lungs of immunized mice 6 h postchallenge than from control mice. The immune sera from mice or guinea pigs contained high titers of antibodies to the homologous isolate and heterologous isolates in a whole-bacterial-cell enzyme-linked immunosorbent assay. Sera against UspA, whether prepared in mice or guinea pigs, had complement-dependent bactericidal activity toward homologous and 11 heterologous M. catarrhalis isolates. These results indicate that the conserved epitopes of the UspA are highly immunogenic and elicit broadly reactive and biologically functional antibodies. UspA may offer protection against M. catarrhalis infections and is being further evaluated as a vaccine candidate.

Animals

Adjuvanticity and protective immunity elicited by Bordetella pertussis antigens encapsulated in poly(DL-lactide-co-glycolide) microspheres.

Purified Bordetella pertussis antigens, encapsulated in biodegradable poly(DL-lactide-co-glycolide) (DL-PLG) microspheres, were evaluated for their immunogenicity and ability to elicit a protective immune response against B. pertussis respiratory infection. Microencapsulated pertussis toxoid, filamentous hemagglutinin, and pertactin all retained their immunogenicity when administered parenterally. Intranasal immunization with a low dose (1 micrograms) of encapsulated filamentous hemagglutinin, pertussis toxoid, or pertactin elicited strong specific immunoglobulin G and immunoglobulin A antibody responses in respiratory secretions that were greater in magnitude than the responses elicited by the same doses of unencapsulated antigen. Intranasal immunization with as little as 1 micrograms of encapsulated pertussis antigen prior to infection reduced the bacterial recovery by 3 log10 CFU. However, intranasal immunization with the same low doses of unencapsulated antigens did not reduce infection. Intranasal administration of a combination of 1 micrograms of each of the microencapsulated pertussis antigens was more effective in reducing bacterial infection than administration of any single microencapsulated antigen. Intranasal administration of microencapsulated B. pertussis antigens elicits high levels of specific antibody coinciding with protection against infection when these microspheres are administered to the respiratory tract. These data provide evidence of the respiratory adjuvanticity of three different DL-PLC microsphere preparations, each of which contains a unique B. pertussis antigen.

Adjuvants, Immunologic

E-box- and MEF-2-independent muscle-specific expression, positive autoregulation, and cross-activation of the chicken MyoD (CMD1) promoter reveal an indirect regulatory pathway.

Members of the MyoD family of gene-regulatory proteins (MyoD, myogenin, myf5, and MRF4) have all been shown not only to regulate the transcription of numerous muscle-specific genes but also to positively autoregulate and cross activate each other's transcription. In the case of muscle-specific genes, this transcriptional regulation can often be correlated with the presence of a DNA consensus in the regulatory region CANNTG, known as an E box. Little is known about the regulatory interactions of the myogenic factors themselves; however, these interactions are thought to be important for the activation and maintenance of the muscle phenotype. We have identified the minimal region in the chicken MyoD (CMD1) promoter necessary for muscle-specific transcription in primary cultures of embryonic chicken skeletal muscle. The CMD1 promoter is silent in primary chick fibroblast cultures and in muscle cell cultures treated with the thymidine analog bromodeoxyuridine. However, CMD1 and chicken myogenin, as well as, to a lesser degree, chicken Myf5 and MRF4, expressed in trans can activate transcription from the minimal CMD1 promoter in these primary fibroblast cultures. Here we show that the CMD1 promoter contains numerous E-box binding sites for CMD1 and the other myogenic factors, as well as a MEF-2 binding site. Surprisingly, neither muscle-specific and the other myogenic factors, as well as a MEF-2 binding site. Surprisingly, neither muscle-specific expression, autoregulation, or cross activation depends upon the presence of of these E-box or MEF-2 binding sites in the CMD1 promoter. These results demonstrate that the autoregulation and cross activation of the chicken MyoD promoter through the putative direct binding of the myogenic basic helix-loop-helix regulatory factors is mediated through an indirect pathway that involves unidentified regulatory elements and/or ancillary factors.

Amino Acid Sequence

Origin of CD4-CD8-B220+ T cells in MRL-lpr/lpr mice. Clues from a T cell receptor beta transgenic mouse.

Abnormal development of T cells in the thymus is thought to be related to autoimmune disease and the expansion of the unusual CD4-CD8-B220+ peripheral T cel subset that results in lymphadenopathy in MRL-lpr/lpr mice. Although we and others have previously shown that rearranged TCR-transgenes alter T cell development in the thymus and abrogate lymphoproliferative disease in lpr mice, the origin and developmental pathway of the LN CD4-CD8-B220+ T cells has not been fully elucidated. We therefore undertook the systematic analysis of the effect of a TCR-beta transgene on the production and differentiation of (lymph node) LN T cells and the production, differentiation, and release of thymocyte T cell populations. In nontransgenic mice, there was increased proliferation of CD4-CD8-B220+ T cells in the LN of adult MRL-lpr/lpr mice compared to MRL(-)+/+ mice, as measured by in vivo BrdU labeling. These proliferating LN T cells were greatly reduced by thymectomy of adult MRL-lpr/lpr mice 1 wk before bromodeoxyuridine labeling, indicating that recent thymic emigrants or factors were required to sustain proliferation. In the thymus, there was increased production and accumulation of CD4+CD8+TCRdull thymocytes in nontransgenic MRL-lpr/lpr compared to MRL(-)+/+ mice. As the rate of maturation from CD4+CD8+TCRdull to CD4+CD8+TCRbright was the same (6%) in both MRL-lpr/lpr and MRL(-)+/+ mice, the accumulation of the immature population in the MRL-lpr/lpr mice could not be due to a maturation defect. However, there was a decrease in apoptosis and intrathymic death of CD4+CD8+TCRdull thymocytes in MRL-lpr/lpr compared to MRL(-)+/+ mice. Introduction of the TCR-beta transgene into lpr/lpr mice normalized the proliferation of T cells in the LN. In the thymus, the TCR-beta transgene resulted in a dramatic increase in maturation efficiency and a reduction in apoptosis in MRL(-)+/+ mice. These data suggest that the TCR transgene inhibits lymphoproliferation by reducing the production of "neglected" CD4+CD8+TCRdull thymocytes that will undergo Fas Ag-mediated apoptosis. They further suggest that in lpr mice, which express a mutated Fas Ag, the "neglected" thymocytes are able to continually escape to the periphery, where they proliferate.

Animals

Progressive myoclonus epilepsy of Unverricht-Lundborg type: a clinical and molecular genetic study of a family from the United States with four affected sibs.

We describe clinical and molecular genetic data on a family from the United States in which four of five sibs are affected with progressive myoclonus epilepsy of Unverricht-Lundborg type. The gene for this disorder (EPM1) has previously been mapped to the distal region of chromosome 21. Molecular genetic results suggest that the disease gene in this family is linked to the same region of chromosome 21. Crossover events in the family help refine the gene localization by placing EPM1 between loci CBS and D21S112.

Child

Isolation and functional comparison of Dmyd, the Drosophila homologue of the vertebrate myogenic determination genes, with CMD1.

We have isolated a cDNA clone, called Dmyd for Drosophila myogenic determination gene, from a 0-16 hour Drosophila embryo library that encodes a protein with structural and functional characteristics similar to the members of the vertebrate MyoD family (Paterson et al 1991). Dmyd encodes a polypeptide of 332 amino acids with 82% identity to MyoD in the 41 amino acids of the putative helix-loop-helix region and 100% identity in the 13 amino acids of the basic domain proposed to contain the essential recognition code for muscle specific gene activation. The gene is unique and maps to 95A/B on the right arm of the third chromosome. Low stringency hybridizations indicate Dmyd is not a member of a multigene family, similar to MyoD in vertebrates. Dmyd is a nuclear protein in Drosophila, consistent with its role as a nuclear gene regulatory factor, and is proposed to be a transiently expressed marker for a unique subset of muscle founder cells. We have used an 8kb promoter fragment from the gene, which contains the first 55 amino acids of the Dmyd protein, joined to lac Z to follow myogenic precursor cells into muscle fibers using antibodies to beta-galactosidase and Dmyd. Unlike the myogenic factors in vertebrate muscle cells, Dmyd appears to be expressed at a much lower level in differentiated Drosophila muscles so it cannot be followed continuously as a muscle marker. This is reflected in the loss of expression of Dmyd RNA in 12-24 hour embryos, a major period of early myogenesis, as well as in the undetectable level of the nuclear antigen in primary cultures of embryonic and adult Drosophila muscle. Functional differences between Dmyd and CMD1 are described and explained in terms of a model which may give insight to the nature of homo and heterodimer formation in the bHLH family of proteins.

Amino Acid Sequence

H. pylori, the most common bacterial infection in Africa: a random serological study.

This study was carried out to determine the prevalence of antibodies to Helicobacter pylori in northern Nigeria, a region with a low incidence of peptic ulceration. In a random, serological survey of 268 subjects, 228 (85%) of the population studied had IgG antibodies to H. pylori. Fifty-eight of these subjects had experienced dyspepsia in the preceding 6 months. The majority of the population (82%) is infected between the ages of 5 and 10. Despite the high prevalence of antibodies to H. pylori, peptic ulcer is uncommon, suggesting that H. pylori is not important in the etiology of peptic ulcer in this population. Indeed, most patients infected by H. pylori are asymptomatic. The possible reasons for this are discussed.

Adolescent

Abnormal thymocyte development and production of autoreactive T cells in T cell receptor transgenic autoimmune mice.

Development of a C57BL/6-+/+ TCR transgenic mouse containing the rearranged TCR alpha- and beta-chain specific for the Db + HY male Ag results in production of a nearly monoclonal population of early thymocytes expressing the Db + HY reactive TCR. These thymocytes are autoreactive in H-2Db male mice and undergo clonal deletion and down-regulation of CD8. To study the effect of the lpr gene on development of autoreactive T cells, these transgenic mice were backcrossed with C57BL/6-lpr/lpr mice. T cell populations in the thymus and spleen were analyzed by three-color flow cytometry for expression of CD4, CD8, and TCR. The thymus of TCR transgenic H-2b/b lpr/lpr male mice had an increase in percent and absolute number of CD8dull thymocytes compared to TCR transgenic H-2b/b +/+ male mice. However, there was not a complete defect in clonal deletion, because clonal deletion and down-regulation of CD8 was apparent in both +/+ and lpr/lpr H-2Db HY+ male mice compared to H-2Db HY- female mice. The phenotype of splenic T cells was almost identical in TCR transgenic +/+ and lpr/lpr males with about 50% CD4-CD8- T cells and 50% CD8+ T cells. However, there was a dramatic increase in the SMLR proliferative response of splenic T cells from TCR transgenic lpr/lpr males compared to TCR transgenic +/+ males. To determine the specificity of this response, spleen cells from TCR transgenic lpr/lpr and +/+ mice were cultured with irradiated H-2b/b and H-2k/k male and female spleen cells. T cells from TCR transgenic C57BL/6-lpr/lpr male mice had an increased proliferative response to H-2b/b male spleen cells compared to T cells from TCR transgenic C57BL/6(-)+/+ male mice, but both lpr/lpr and +/+ mice had a minimal response to irradiated H-2b/b female or H-2k/k male or female stimulator cells. The splenic T cells from TCR transgenic lpr/lpr mice also had an increased specific cytotoxic activity against H-2b/b male target cells compared to TCR transgenic +/+ mice. These results demonstrate that there is a defect in negative selection of self-reactive T cells in the thymus of lpr/lpr mice and a defect in induction or maintenance of clonal anergy of self-reactive T cells in the periphery of lpr/lpr mice.

Animals

The Drosophila homologue of vertebrate myogenic-determination genes encodes a transiently expressed nuclear protein marking primary myogenic cells.

We have isolated a cDNA clone, called Dmyd for Drosophila myogenic-determination gene, that encodes a protein with structural and functional characteristics similar to the members of the vertebrate MyoD family. Dmyd clone encodes a polypeptide of 332 amino acids with 82% identity to MyoD in the 41 amino acids of the putative helix-loop-helix region and 100% identity in the 13 amino acids of the basic domain proposed to contain the essential recognition code for muscle-specific gene activation. Low-stringency hybridizations indicate that Dmyd is not a member of a multigene family similar to MyoD in vertebrates. Dmyd is a nuclear protein in Drosophila, consistent with its role as a nuclear-gene regulatory factor, and is proposed to be a transiently expressed marker for muscle founder cells. We have used an 8-kilobase promoter fragment from the gene, which contains the first 55 amino acids of the Dmyd protein, joined to lacZ, to follow myogenic precursor cells into muscle fibers with antibodies to beta-galactosidase and to Dmyd. Unlike the myogenic factors in vertebrate muscle cells, Dmyd appears to be expressed at a much lower level in differentiated Drosophila muscles, so Dmyd cannot be followed continuously as a muscle marker. This fact is reflected in the loss of Dmyd RNA expression in 12- to 24-hr embryos, a major period of early myogenesis, as well as in the undetectable level of the nuclear antigen in primary cultures of embryonic and adult Drosophila muscle.

Age Factors

Serological evidence of infection with Helicobacter pylori may predict gastrointestinal intolerance to non-steroidal anti-inflammatory drug (NSAID) treatment in rheumatoid arthritis.

Specific circulating antibodies to the spiral gastric organism, Helicobacter pylori (HP) were detectable in 43% of 68 patients with rheumatoid arthritis by complement fixation test (CFT) and enzyme-linked immunosorbent assay (ELISA), a frequency comparable with that of a normal, age-matched population. Presence of these antibodies correlated strongly with a previous history of peptic ulcer disease (PUD) and to the severity of NSAID-related dyspeptic symptoms, the latter often leading to multiple drug intolerance. This contrasts with short term, prospective NSAID toxicity data, which show little relationship between ulceration and HP carriage. This result suggests, however, that HP may have a definite role in the pathogenesis of symptomatic PUD associated with more chronic NSAID usage, and may have important implications for ulcer prophylaxis in these patients.

Adult

Transgenic rearranged T cell receptor gene inhibits lymphadenopathy and accumulation of CD4-CD8-B220+ T cells in lpr/lpr mice.

The lpr gene in homozygous form induces development of CD4-CD8-B220+ T cells and lymphadenopathy in MRL and C57BL/6 mice. Although the propensity for excessive production of T cells is related to an intrinsic T cell defect, a thymus is also required because neonatal thymectomy eliminates lymphadenopathy. Recent evidence suggests that excessive production and release of autoreactive T cells from the thymus of lpr/lpr mice might lead to downregulation of CD4 and CD8 as a "fail safe" tolerance mechanism that occurs during late thymic or post-thymic development. To test this hypothesis, T cell receptor (TCR) transgenic mice that produce large numbers of immature thymocytes recognizing the H-2Db and male H-Y antigens were backcrossed with C57BL/6-lpr/lpr mice and MRL-lpr/lpr mice. It was predicted that Db male lpr/lpr mice would produce large numbers of autoreactive T cells during early thymic development that would lead to an accelerated lymphoproliferative disease. In contrast, Db female lpr/lpr mice would produce large numbers of Db H-Y-reactive T cells, but might not develop lymphadenopathy because the male H-Y antigen would not be present. Unexpectedly, there was complete elimination of lymphadenopathy in both male and female TCR transgenic lpr/lpr mice. The elimination of lymphadenopathy was not due to a failure of thymic maturation since the thymus of H-2Db female lpr/lpr mice contained nearly normal numbers of mature thymocytes. Elimination of lymphadenopathy was also not due to a lack of autoreactive T cells in the peripheral lymph nodes (LN) since there was an increased syngeneic mixed lymphocyte proliferative response of LNT cells from transgenic lpr/lpr compared with +/+ mice in vitro. Hypergammaglobulinemia and autoantibody production in the transgenic lpr/lpr was present at levels comparable with or higher than control nontransgenic lpr/lpr mice, suggesting a dissociation of autoantibody production from the lymphoproliferative disease in the TCR transgenic mice. Conversely, the development of lymphadenopathy and production of CD4-CD8-B220+ T cells appear to be intimately linked, as both were completely eliminated in T cells expressing the transgenic TCR. We propose that lymphoproliferation and production of CD4-CD8-6B2+ T cells in lpr/lpr mice is related to decreased expression of the TCR, and providing the T cells with a rearranged TCR transgene overcomes this defect.

Animals

An avian muscle factor related to MyoD1 activates muscle-specific promoters in nonmuscle cells of different germ-layer origin and in BrdU-treated myoblasts.

We isolated the cDNA encoding a myogenic factor expressed in embryonic chick breast muscle by virtue of its weak hybridization to the mouse MyoD1 clone. Nucleotide sequence analysis and amino acid comparison define this clone, CMD1, as encoding a protein similar to mouse MyoD1. CMD1 encodes a polypeptide smaller than MyoD1, 298 versus 318 amino acids, respectively, and is 80% concordant by amino acid sequence overall. The basic and myc domains required for myogenic conversion of mouse 10T1/2 'fibroblasts' to myoblasts with MyoD1 are completely conserved in CMD1. CMD1 is just as efficient as the mouse homolog in myogenic conversion of 10T1/2 cells and coactivates the endogenous mouse MyoD1 gene in the process. The efficiency of myoblast conversion depends on the levels of CMD1 expression and suggests that the cellular concentration of CMD1 plays a role in the onset of myogenesis. Transient expression of CMD1 in a variety of nonmuscle cells from different germ-layer origins activates both cotransfected muscle-specific promoters and, in some cases, endogenous muscle-specific genes. 5-Bromodeoxyuridine (BrdU) treatment of chicken and mouse myoblasts reduces the expression of CMD1 and MyoD1, respectively, and may explain how this thymidine analog inhibits myogenesis and the activity of transfected muscle-specific promoters in BrdU-treated myoblasts. Transient expression of CMD1 in BrdU-treated myoblasts reactivates cotransfected muscle-specific promoters. CMD1 activates muscle-specific promoters in cotransfections regardless of cell type, whereas 'housekeeping' or constitutive promoters can be activated moderately, unaffected, or repressed, depending on the promoter and cell background. The rate and degree of myogenic conversion may be more restricted by cell phenotype than by germ-layer origin.

Amino Acid Sequence

Antipneumococcal effects of C-reactive protein and monoclonal antibodies to pneumococcal cell wall and capsular antigens.

Antibodies to pneumococcal capsular polysaccharides are well known for their ability to protect against pneumococcal infection. Recent studies indicate that antibodies to cell wall antigens, including pneumococcal surface protein A and the phosphocholine (PC) determinant of teichoic acids as well as human C-reactive protein (which also binds to PC), can protect mice against pneumococcal infection. In the present study we compared the protective effects of these agents as measured by mouse protection, the blood bactericidal assay, and clearance of pneumococci from the blood and peritoneal cavity. Our findings extend previous results indicating that human C-reactive protein and antibodies to noncapsular antigens are generally less protective than anticapsular antibodies. The new results obtained indicate the following: (i) mouse protection studies with intraperitoneal and intravenous infections provide very similar results; (ii) monoclonal immunoglobulin G2a (IgG2a) antibodies to PC, like IgG1, IgG2b, and IgG3 antibodies to PC, are highly protective against pneumococcal infection in mice; (iii) human antibody to PC is able to protect against pneumococcal infection in mice; (iv) antibodies to PspA are effective at mediating blood and peritoneal clearance of pneumococci; (v) complement is required for the in vivo protective effects of both IgG and IgM antibodies to PC; (vi) IgG1, IgG2b, and IgG3 anti-PC antibodies all mediate complement-dependent lysis of PC-conjugated erythrocytes; and (vii) antibodies and human C-reactive proteins that are reactive with capsular antigens but not cell wall antigens are able to mediate significant antibacterial activity in the blood bactericidal assay.

Animals

Further evidence of von Willebrand factor involvement in thrombotic thrombocytopenia purpura.

Fourteen patients diagnosed as having thrombotic thrombocytopenia purpura (TTP) were studied. Those who survived have been followed during a 1 to 7 year period. The clinical diagnosis was based on changing neurological findings, thrombocytopenia and evidence of microangiopathic hemolytic anemia. Laboratory tests included the determination of von Willebrand factor antigen (VWF:Ag), ristocetin cofactor (RiCof) and the electrophoretic mobility of von Willebrand factor (CIE VWF:Ag). The ratio of RiCof to VWF:Ag was then calculated. Control individuals included healthy subjects and patients with thrombocytopenia of several etiologies. Statistical differences between the values of RiCof, the ratio of RiCof:VWF:Ag and the CIE of VWF:Ag were found for samples comparing active disease and remission phase. The recovery from thrombocytopenia paralleled the correction of abnormal parameters. Similarly, significant differences were found when above parameters were compared between thrombocytopenia of TTP with other thrombocytopenic states. We suggest that these abnormal tests could be useful in distinguishing TTP from other disorders, and may have prognostic significance in patients already diagnosed as having TTP.

Adolescent