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Biomedical subjects

C McCall

Publications and source records attributed to C McCall.

At least 19 recordsLinked to original sources
PubMed2001

Cloning and characterization of cDNAs encoding four different canine immunoglobulin gamma chains.

cDNAs encoding four different canine immunoglobulin G (caIgG) gamma chains were identified in this study. One of these IgG gamma chain cDNAs, (caIgG-A), represents 92.5% of the IgG gamma chain cDNAs in a dog spleen cell cDNA library; a second partial IgG gamma chain cDNA (caIgG-B) was also identified in the library. The other two IgG gamma chain cDNAs (caIgG-C and caIgG-D) were RT-PCR amplified from canine lymphoma samples. Comparison of the four different canine IgG gamma chain cDNAs showed homologies from 83.6 to 89.2% and from 73.1 to 81.8% at nucleotide and amino acid sequence levels, respectively. Despite the high similarity in CH1, CH2 and CH3 domains among the different caIgG gamma chains, the hinge regions were distinct, sharing only 19.0-35.2% homology at the amino acid level. No multiple duplication of the hinge region, as reported for human IgG1 and IgG3, was detected in any of the canine IgG gamma chains. The numbers of cysteines in the putative hinge regions were found to be 3, 2, 7 and 3 for the four canine IgG heavy gamma chains (A, B, C and D), respectively. Specific primers were designed based on caIgG gamma chain hinge region DNA sequences and were used in RT-PCR for measuring different caIgG gamma chain mRNA levels in canine PBMC samples.

Amino Acid Sequence↗
PubMed2001

Characterization and cloning of a major high molecular weight house dust mite allergen (Der f 15) for dogs.

Although house dust mites (HDM(s)) are important elicitors of canine allergy, the low molecular weight molecules defined as major allergens for humans do not appear to be major allergens for dogs. Western blotting of Dermatophagoides farinae (D. farinae) extracts with sera from sensitized dogs showed that the majority of animals had IgE antibodies specific for two proteins of apparent molecular weights of 98 and 109kDa (98/109kDa). The N-terminal sequences of these two proteins were identical, suggesting they were very closely related, and sequencing of internal peptides showed the protein(s) to have homology with insect chitinases. A purified preparation of 98/109kDa proteins elicited positive intradermal skin tests (IDST(s)) in a group of well-characterized atopic dogs sensitized to D. farinae, but not in normal dogs. A rabbit polyclonal antiserum raised against the purified proteins was used to immunoscreen a D. farinae cDNA library. The mature coding region of the isolated chitinase cDNA predicts a protein of 63.2kDa; sequence analysis and glycan detection blotting suggest that the molecule is extensively O-glycosylated. Monoclonal antibodies made against the purified native protein were used to localize the chitinase in sections of whole D. farinae mites. The protein displayed an intracellular distribution in the proventriculus and intestine of the mite, suggesting that it has a digestive, rather than a moulting-related, function. The high prevalence of IgE antibodies to this antigen in canine atopic dermatitis makes it a major HDM allergen for dogs, and the protein has been formally designated Der f 15.

Amino Acid Sequence↗
PubMed2001

Measurement of canine IgE using the alpha chain of the human high affinity IgE receptor.

In vitro assays for allergen specific immunoglobulin E (IgE) are a convenient and reproducible alternative to intradermal skin testing in dogs. Such tests may be used to support a diagnosis of atopic dermatitis and to define appropriate allergens for immunotherapy. Current in vitro assays rely upon monoclonal or polyclonal antibodies as IgE detection reagents. However, in sera where allergen-specific IgG occurs in great excess, any IgE:IgG cross-reactivity of the detection reagent may result in lowered assay specificity. Therefore, we have developed an assay for canine IgE which uses a recombinant form of the extracellular part of the alpha chain of the human high affinity IgE receptor (FcvarepsilonRIalpha). Biotinylated FcvarepsilonRIalpha shows no significant binding to purified canine IgG, and recognizes a heat labile antibody in serum, with a detection limit of 73-146pg/ml. Comparison of assay signals using the labeled FcvarepsilonRIalpha and a highly specific anti-canine IgE monoclonal antibody (MAb) shows good agreement. The FcvarepsilonRIalpha is therefore a sensitive and specific alternative to polyclonal or monoclonal antibodies for canine serum IgE measurement.

Animals↗
PubMed2001

Recombinant canine IL-13 receptor alpha2-Fc fusion protein inhibits canine allergen-specific-IgE production in vitro by peripheral blood mononuclear cells from allergic dogs.

Human IL-13, like IL-4, is involved in the regulation of B-cell development, IgE synthesis and allergic responses. However, because IL-13 does not affect either murine Ig class switching or IgE production in vitro, the use of murine models to study the role of IL-13 in IgE-mediated diseases has been limited. In this communication, we report that recombinant protein of canine IL-13 (rcaIL-13) stimulates production of allergen-specific-IgE in vitro by peripheral blood mononuclear cells (PBMC) from flea allergen-sensitized dogs, and that this stimulation activity is specifically inhibited by recombinant protein of canine IL-13Ralpha2 and Fc fragment of canine IgG heavy chain (rcaIL-13Ralpha2-Fc). The data suggest that the regulatory effects of IL-13 on IgE production in canine PBMC are similar to those reported in humans. Thus, canine IL-13 may be a central mediator of allergic diseases in dogs, and allergic dogs may be excellent models for research on IgE-mediated diseases in humans.

Amino Acid Sequence↗
PubMed2001

Are keloids really "gli-loids"?: High-level expression of gli-1 oncogene in keloids.

BACKGROUND: Keloids are a common lesion arising from sites of previous trauma and are a considerable source of morbidity because of continued growth of lesions, pruritus, and physical appearance. They consist of mesenchymal cells embedded in a stroma of disordered collagen matrix. Clinically, keloids are distinguished from scars in that keloids demonstrate continued growth over the borders of the original injury. Keloids appear with increased frequency in patients of African and Asian descent. Currently, no entirely satisfactory method of treatment exists for these lesions. Recently, a patient who was enrolled in a clinical trial of topical tacrolimus for atopic dermatitis applied this drug to a keloid and noted clearing. OBJECTIVE: Based on this clinical observation and the observation that rapamycin, a chemically similar compound to tacrolimus, is known to inhibit signaling from the gli-1 oncogene, we examined keloids and scars for expression of Gli-1 protein. METHODS: Skin sections from keloids and scars were examined by immunohistochemical staining for gli-1. To further confirm the presence of gli-1 expression in keloids, reverse transcriptase-polymerase chain reaction was carried out. RESULTS: Expression of gli-1 was strongly elevated in keloids compared with scars. CONCLUSION: These results provide a rationale for the treatment of keloids with topical rapamycin analogs, including tacrolimus. Clinical trials of topical tacrolimus are warranted.

DNA↗
PubMed2001

Canine interleukin-5: molecular characterization of the gene and expression of biologically active recombinant protein.

Interleukin-5 (IL-5), which is produced primarily by type 2 T helper lymphocytes (Th2), is an eosinophil differentiation and activation factor. Increased numbers of eosinophils in peripherial blood or tissues (eosinophilia) are observed in asthmatic human patients, in animals with helminth infections, and in dogs with allergic diseases. Antagonism of IL-5 activity is being explored as a potential treatment of a number of disease conditions associated with eosinophils in animal models. In order to study the expression and function of this cytokine in the dog, we have isolated and characterized the canine IL-5 gene. The canine IL-5 polypeptide deduced from the cDNA is composed of 134 amino acids that share varying degrees of homology with IL-5 isolated from several mammals. The genomic structure of the canine IL-5 gene consists of four exons and three introns in the coding region, similar to that of the previously characterized human and mouse IL-5 genes. Recombinant canine IL-5 protein, expressed in Pichia pastoris, is biologically active in a cell proliferation assay. Canine IL-5 gene sequences and the biologically active protein described in this study will be useful reagents for future studies of this cytokine in physiologic processes and in pathologic conditions of the dog.

Amino Acid Sequence↗
PubMed2000

Identification, cloning, and characterization of a major cat flea salivary allergen (Cte f 1).

An 18 kDa protein isolated from saliva of the cat flea, Ctenocephalides felis, elicits a positive intradermal skin test (IDST) in 100 and 80% of experimental and clinical flea allergic dogs, respectively. Using solid-phase enzyme-linked immuno assay (ELISA), this protein detected IgE in 100 and 80% of experimental and clinical flea allergic dogs, respectively. A cDNA (pFSI) encoding a full-length Cte f 1 protein was isolated from a C. felis salivary gland cDNA library, using a combination of PCR and hybridization screening. This cDNA is 658 bp in length, and contains an open reading frame of 528 bp. The open reading frame encodes a protein of 176 amino acids, consisting of an 18 amino acid signal sequence and a 158 amino acid mature protein. The calculated molecular weight and pI of the mature protein are 18106 Da and 9.3, respectively. The protein, named Cte f 1, is the first novel major allergen described for canine flea allergy. Recombinant Cte f 1 (rCte f 1) was expressed in Escherichia coli, Pichia pastoris and baculovirus infected Trichoplusia ni cells. Approximately, 90% of the rCte f 1 expressed in E. coli accumulated in insoluble inclusion bodies, which could be refolded to a soluble mixture of disulfide isomers with partial IgE binding activity. Small quantities of an apparently correctly refolded form of rCte f 1, which had IgE binding activity equal to the native antigen, was isolated from the soluble fraction of E. coli cells. However, P. pastoris and baculovirus infected insect cells expressed and secreted a fully processed, correctly refolded and fully active form of rCte f 1. Mass spectrometry analysis of the active forms of rCte f 1confirmed that eight intact disulfide bonds were present, matching the number observed in the native allergen. The relative ability of rCte f 1 to bind IgE in the serum of flea allergic animals, produced in these three expression systems, matched that of the native allergen. Competition ELISA demonstrated that approximately 90% of the specific IgE binding to native Cte f 1 could be blocked by the different forms of rCte f 1.

Alkylation↗
PubMed2000

Weal and flare responses to intradermal rocuronium and cisatracurium in humans.

Thirty volunteers underwent intradermal skin testing with increasing concentrations of rocuronium and cisatracurium to evaluate weal and flare responses, and whether either agent would cause mast cell degranulation and sensitization upon re-exposure. We found that intradermal injection of rocuronium and cisatracurium at concentrations > 10(-4) M resulted in positive weal (>8 mm) responses, and positive flare responses at > 10(-4) and > 10(-5) M respectively. Only cisatracurium caused mild to moderate mast cell degranulation, and neither drug caused significant in vitro histamine release from whole blood collected from study subjects 4 weeks after skin testing. Skin testing with rocuronium and cisatracurium should be performed at concentrations < 10(-4) and < 10(-5) M respectively to avoid false-positive responses. The ability of these agents to produce positive weal and flare responses at relatively low concentrations may explain the high incidence of potential reactions reported.

Androstanols↗
PubMed1999

Hemispheric lateralization in the processing of odor pleasantness versus odor names.

It is well established that for most people linguistic processing is primarily a left hemisphere activity, whereas recent evidence has shown that basic odor perception is more lateralized to the right hemisphere. Importantly, under certain conditions, emotional responding also shows right hemisphere laterality. Hedonic (pleasantness) assessments constitute basic level emotional responses. Given that olfaction is predominantly ipsilateral in function, it was hypothesized that odor pleasantness evaluations may be accentuated by right nostril perception and that odor naming would be superior with left nostril perception. To test this prediction we presented eight familiar neutral-mildly pleasant odors for subjects to sniff through the left and right nostrils. Subjects smelled each odor twice (once through each nostril) at two different sessions, separated by 1 week. At each session subjects provided pleasantness, arousal and naming responses to each odorant. Results revealed that odors were rated as more pleasant when sniffed through the right nostril and named more correctly when sniffed through the left. No effects for arousal were obtained. These findings are consistent with previously demonstrated neural laterality in the processing of olfaction, emotion and language, and suggest that a local and functional convergence may exist between olfaction and emotional processing.

Adolescent↗
PubMed1999

Bacterial lipopolysaccharide induction of the prostaglandin G/H synthase 2 gene causes thromboxane-dependent pulmonary hypertension in rabbits.

Two genes encode proteins with prostaglandin G/H synthase (PGHS) activity. PGHS-1 is primarily a constitutively expressed gene, whereas inflammatory agents such as bacterial lipopolysaccharide (LPS) endotoxin rapidly induce the PGHS-2 gene in leukocytes. Both PGHS-1 and PGHS-2 are rate-limiting enzymes for the production of prostaglandins and thromboxane following release of arachidonic acid by phospholipases. We previously reported that LPS perfusion into the circulation of isolated perfused rabbit lung (IPL) results in thromboxane-dependent pulmonary hypertension and lung edema when the LPS-primed lung is subsequently stimulated with platelet activating factor (PAF) (J. Clin. Invest. 1990;85:1135). In this study, we showed that the mechanism by which LPS primes IPL for enhanced production of thromboxane and pulmonary hypertension in response to PAF depends on specific upregulation of the PGHS-2 gene in the rabbit lung. LPS perfusion of IPL induced PGHS-2 gene expression, which correlated with the conversion of free arachidonic acid to thromboxane-B2 (TXB2) and the onset of pulmonary hypertension. LPS-induced PGHS-2 expression, TXB2 release, and pulmonary hypertension were inhibited by actinomycin D (an inhibitor of transcription) and cycloheximide (an inhibitor of protein synthesis). The constitutively expressed PGHS-1 remained unchanged with LPS perfusion, and did not convert free arachidonic acid to TXB2, suggesting that PGHS-1 does not contribute to the induction of pulmonary hypertension by LPS. These studies reveal a pathogenic role for induction of PGHS-2 in lung injury.

Animals↗
PubMed1998

Molecular mechanisms responsible for endotoxin tolerance.

Bacterial lipopolysaccharide endotoxin (LPS) is a potent activator of a number of inflammatory genes, including interleukin-1 (IL-1). IL-1 and other cytokines such as tumor necrosis factor alpha (TNF alpha) are essential mediators in inducing severe sepsis syndromes (SS). Major cellular targets of LPS are blood or tissue leukocytes, such as macrophages and neutrophils. These cells can respond and adapt to LPS, the latter phenomenon is known as LPS tolerance. In animals, LPS tolerance is a highly effective mechanism of protection against the lethal syndrome of severe sepsis. Two models are used to investigate the molecular basis of LPS tolerance. The first model employs blood leukocytes isolated from patients with SS. The second model employs the promonocytic cell line, THP-1 in vitro. In the SS model, LPS tolerance of involves repression at the level of IL-1 beta mRNA. Suppression of IL-1 beta mRNA is under the control of a labile repressor protein. In contrast to suppression of IL-1 beta, mRNA is under the control of a labile repressor protein. In contrast to suppression of IL-1 beta, there is increased expression of the Type 2 IL-1 receptor mRNA and protein in leukocytes from patients with SS. The THP-1 model of LPS tolerance also involves repression of LPS induction of IL-1 beta gene expression. The repression of THP-1 cell IL-1 beta expression is at the level of transcription, and like the SS model is under the control of a labile protein. LPS tolerance in both models is stimulus-specific. We further find that transcription factors such as NF kappa B and AP-1 may participate in regulating LPS tolerance.

Cell Line↗
PubMed1996

Treatment of traumagenic beliefs among sexually abused girls and their mothers: an evaluation study.

The objective of this study was to evaluate and compare the efficacy of two short-term individual therapy interventions for sexually abused girls and their nonoffending female caretakers. Thirty-two girls, ages 8 to 13, and their caretakers from primarily low-income, African-American families were randomly assigned to a theoretically based, structured experimental treatment program or to a relatively unstructured comparison intervention. Measures of child outcome were completed before and after the treatment program by each parent and child, and by a clinician blind to treatment condition. Pre- and postmeasures of maternal outcome were completed by the caretaker and a clinician not involved in the treatment. Both treatment programs yielded decreases in children's posttraumatic stress disorder symptoms and traumagenic beliefs reflecting self-blame and powerlessness, and increases in children's overall psychosocial functioning. The experimental intervention was more effective than the comparison program in increasing abuse-related caretaker support of the child and in decreasing caretaker self-blame and expectations of undue negative impact of the abuse on the child. Clinical implications of these findings include the development of interventions targeting sexually abused children's traumagenic beliefs and nonoffending parents' support of their victimized children.

Adolescent↗
PubMed1993

Comparison of the allergenicity of ovalbumin and ovalbumin peptide 323-339. Differential expansion of V beta-expressing T cell populations.

We analyzed the effects of sensitization of BALB/c mice to the OVA peptide amino acids 323-339, on the development of an IgE response, immediate cutaneous hypersensitivity and airways responsiveness (AR). Daily aerosolization of OVA 323-339 for 20 min over a period of 10 days was as effective in the stimulation of a serum anti-OVA IgE antibody response as sensitization to native OVA by the same route. After sensitization to native OVA, the majority of the IgE anti-OVA response was directed against peptide 323-339. The antibody responses were paralleled by skin test responses in sensitized mice: 73% of OVA-sensitized mice developed immediate type reactions when tested with native OVA and 82% of the mice had positive immediate skin test responses to intradermal injection of peptide 323-339. After sensitization to the peptide, 69% of the mice had positive responses to native OVA and 77% responded to peptide 323-339. Aerosolization of OVA as well as OVA 323-339 led to a comparable increase in airway responsiveness as measured by electrical field stimulation of tracheal smooth muscle preparations. To characterize T cell subpopulations that were stimulated after allergen sensitization, the distribution of specific V beta-expressing T cells was analyzed in local draining lymph nodes of the airways and the lungs. These lymph nodes were found to be enlarged after both OVA and OVA peptide sensitization. Sensitization to native OVA resulted in an increased percentage of V beta 8.1 and V beta 8.2 T cells whereas selective stimulation of V beta 8.1 T cells was found after peptide sensitization. These data indicate that OVA peptide 323-339 represents a T and B cell epitope of OVA, which is important in the generation and development of immediate hypersensitivity responses in BALB/c mice.

Airway Resistance↗
PubMed1992

A membrane vesicle/ribosome preparation from Serratia marcescens elicits peritoneal exudate cells expressing both tumoricidal and bactericidal activity.

A biological response modifier called ImuVert, derived from the bacterium Serratia marcescens, produced long-lasting elevation of peritoneal exudate cell (PEC) numbers after intraperitoneal injection into mice. These cells had enhanced ability to phagocytose both latex beads and opsonized Listeria monocytogenes. PEC harvested 2-14 days after a single injection of ImuVert killed L. monocytogenes, and ImuVert protected mice from infection by L. monocytogenes, measured both by LD50 and bacterial growth in vivo. Cells harvested 7 and 14 days after ImuVert injection also were tumoricidal, measured as killing of P815 mastocytoma cells, and ImuVert induced macrophages to express tumoricidal properties in vitro. These data suggest that ImuVert has a unique ability to induce a chronic inflammatory response, as other agents do not induce such a long-lasting influx of bactericidal inflammatory cells that also show tumoricidal activity. The consequences of this response appear to include protection from infection by certain bacteria.

Animals↗
PubMed1992

Adenovirus E1A makes two distinct contacts with the retinoblastoma protein.

Two regions near the amino terminus of the adenovirus E1A protein, which were first identified by sequence conservation among various adenovirus serotypes, have been shown by genetic studies to be essential for E1A-mediated transformation. These same regions are also required for interaction with a number of cellular proteins, including the retinoblastoma protein (pRB). Using synthetic peptides corresponding to portions of these conserved regions, we show that each region can bind independently to pRB. These interactions were observed in both competition and binding assays. In both types of assay, region 2 peptides (E1A amino acids 115 to 132) bound pRB with higher affinity than did region 1 peptides (E1A amino acids 37 to 54), while a peptide combining region 1 and 2 sequences consistently provided the highest-affinity interaction. Cross-blocking experiments using region 1 peptides and region 2 peptides suggested that these two regions of E1A make distinct contacts with pRB. These data support the notion that the pRB-binding domain of E1A contains at least two functional elements.

Adenovirus Early Proteins↗
PubMed1991

Human cyclin A and the retinoblastoma protein interact with similar but distinguishable sequences in the adenovirus E1A gene product.

The adenovirus early region 1A (E1A) proteins associate with several cellular proteins in adenovirus infected or transformed cells. Recently, two of the cellular proteins that bind to E1A encoded proteins have been identified. p105 has been shown to be the product of the retinoblastoma tumor suppressing gene. p60 has been shown to be a human cyclin A. Previously studies have shown that E1A protein sequences encoded by conserved domains 1 and 2 are required for interactions with the retinoblastoma protein (pRB). We have demonstrated here that amino acids 30 to 60 and 121 to 127 within the E1A proteins are required for interaction with p60/cyclin A. These are the same sites within conserved domains 1 and 2 that are required for E1A protein association with pRB. However, the association of p60/cyclin A does not appear to require pRB. We also demonstrate that another cellular protein, 130K, interacts with E1A at essentially the same sites. It is interesting that mutations in these regions destroy the ability of E1A to function as an oncogene, thereby raising the possibility that interaction with several different cellular proteins may be needed for transformation by E1A.

Adenoviridae↗
PubMed1987

Effect of an inhibitor of protein kinase C on human polymorphonuclear leukocyte degranulation.

The protein kinase C inhibitor C-I reduced superoxide production by human neutrophils in response to phorbol myristate acetate by greater than 50%. In contrast to its effects in oxidative metabolism, 100 microM C-I caused minimal inhibition (5-18%) of lysozyme release in response to phorbol myristate acetate. Enzyme release produced by the formylated oligopeptide FMLP was enhanced by 23-54% in neutrophils pretreated with 100 microM C-I. These findings suggest that protein kinase C activation is not required for phorbol myristate acetate induced enzyme release. Enhancement of FMLP stimulated degranulation by C-I suggests that protein kinase C activation may have inhibitory effects on the release of granule enzymes by human neutrophils.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗