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T Barrett

Publications and source records attributed to T Barrett.

At least 19 recordsLinked to original sources
PubMed1999

The MKK7 gene encodes a group of c-Jun NH2-terminal kinase kinases.

The c-Jun NH2-terminal protein kinase (JNK) is a member of the mitogen-activated protein kinase (MAPK) group and is an essential component of a signaling cascade that is activated by exposure of cells to environmental stress. JNK activation is regulated by phosphorylation on both Thr and Tyr residues by a dual-specificity MAPK kinase (MAPKK). Two MAPKKs, MKK4 and MKK7, have been identified as JNK activators. Genetic studies demonstrate that MKK4 and MKK7 serve nonredundant functions as activators of JNK in vivo. We report here the molecular cloning of the gene that encodes MKK7 and demonstrate that six isoforms are created by alternative splicing to generate a group of protein kinases with three different NH2 termini (alpha, beta, and gamma isoforms) and two different COOH termini (1 and 2 isoforms). The MKK7alpha isoforms lack an NH2-terminal extension that is present in the other MKK7 isoforms. This NH2-terminal extension binds directly to the MKK7 substrate JNK. Comparison of the activities of the MKK7 isoforms demonstrates that the MKK7alpha isoforms exhibit lower activity, but a higher level of inducible fold activation, than the corresponding MKK7beta and MKK7gamma isoforms. Immunofluorescence analysis demonstrates that these MKK7 isoforms are detected in both cytoplasmic and nuclear compartments of cultured cells. The presence of MKK7 in the nucleus was not, however, required for JNK activation in vivo. These data establish that the MKK4 and MKK7 genes encode a group of protein kinases with different biochemical properties that mediate activation of JNK in response to extracellular stimuli.

Alternative Splicing↗
PubMed1998

Pretreatment with intralesional hyaluronidase prior to excision of dermatofibrosarcoma protuberans.

Dermatofibrosarcoma protuberans (DFSPs) are an uncommon malignancy that commonly recur, but rarely metastasize. The origin of DFSPs is controversial; however, they stain with the progenitor marker CD34. DFSPs usually show increased stromal mucin, mainly hyaluronic acid (HA). HA increases cellular proliferation, delays differentiation and increases cellular motion. We evaluated the pretreatment of DFSPs with intralesional injections of hyaluronidase (HD) prior to the surgical excision. Five of nine cases of DFSPs were pretreated with HD. In HD-pretreated cases the margins for excision of the residual tumor were reduced. HD pretreatment also decreased CD34 staining and increased polarizable collagen in the residual tumor.

Adult↗
PubMed1998

Serological evidence of morbillivirus infection in small cetaceans from the Southeast Pacific.

The presence of morbillivirus-specific serum antibodies was examined by an indirect enzyme linked immunosorbent assay (iELISA) and virus neutralization tests in serum samples from 30 dusky dolphins (Lagenorhynchus obscurus), 8 long-snouted common dolphins (Delphinus capensis), 2 inshore and 6 offshore bottlenose dolphins (Tursiops truncatus) and 20 Burmeister's porpoises (Phocoena spinipinnis) taken in fisheries off central Peru in 1993-1995. The sera from six dusky dolphins, one common dolphin and three offshore bottlenose dolphins were positive on a coat of dolphin morbillivirus (DMV) antigen in the iELISA. Several of these sera were also positive when tested against peste des petits ruminants and rinderpest virus antigen. Porpoise morbillivirus and/or DMV neutralizing antibodies were detected in the sera of two bottlenose and three dusky dolphins that reacted positively with DMV antigen in iELISA and also in the sera of one common, one dusky and one bottlenose dolphin that were negative in the iELISA. These results strongly suggest that viruses closely related, or identical, to the cetacean morbillivirus present in the North Atlantic and the Mediterranean Sea infect several species of Delphinidae of the Southeastern Pacific. No convincing morbillivirus-specific antibody positive reactions were detected in the sera from either the Burmeister's porpoises or the inshore bottlenose dolphins.

Animals↗
PubMed1998

Refined mapping of the gene for thiamine-responsive megaloblastic anemia syndrome and evidence for genetic homogeneity.

Thiamine-responsive megaloblastic anemia (TRMA, also known as Rogers syndrome, OMIM 249270) is a rare autosomal recessive disorder characterized by a triad of megaloblastic anemia, diabetes mellitus, and sensorineural deafness. Patients respond, to varying degrees, to treatment with megadoses of thiamine. We have recently shown genetic linkage of the TRMA gene to a 16-centimorgan (cM) region on 1q23.2-1q23.3 based on the analysis of four large, inbred families of Alaskan, Italian, and Israeli-Arab origin. Here we narrow the TRMA interval down to 4 cM based on genetic recombination, homozygosity mapping, and linkage disequilibrium (highest LOD score of 12.5 at D1S2799, at a recombination fraction of 0). We provide further evidence that the TRMA gene is located in this region and confirm the homogeneity of the disease. In this analysis, we genotyped seven additional families of diverse ethnic origin (Pakistani, Indian, Italian, Brazilian, and Japanese), and analyzed additional markers in two previously reported families showing evidence of linkage disequilibrium in a large area of their haplotypes. The multi-system manifestations of TRMA suggest that thiamine has a pivotal role in a multiplicity of physiological processes. Mapping the TRMA gene and understanding the molecular basis of the disease might, thus, shed light on the role of thiamine in common disorders such as deafness, anemia, and diabetes.

Anemia, Megaloblastic↗
PubMed1998

Fluoroquinolone-resistant Moraxella catarrhalis in a patient with pneumonia: report from the SENTRY Antimicrobial Surveillance Program (1998).

Fluoroquinolone resistance in Moraxella catarrhalis isolates has been quite rare. This report presents a case history of a 22-year-old man with compromised immune status and severe pneumonia caused by M. catarrhalis. The organism was markedly resistant (MICs, 1.5- > 32 micrograms/mL) to several marketed fluoroquinolones including the agent (levofloxacin) used for concurrent and prior therapy. The emergence of this problematic strain seems related to chronic exposure of the patient to compounds in the class and poor patient compliance to prescribed medications. The strain was not clonally related to other M. catarrhalis strains isolated in the same hospital during early 1998. This second documented case of a fluoroquinolone-resistant M. catarrhalis clinical isolate presents a warning that resistances can emerge in at-risk patients, and that surveillance systems (SENTRY) will be necessary to monitor for unusual organisms and spread of resistance phenotypes among commonly isolated respiratory tract pathogens.

Adult↗
PubMed1998

Prilocaine-phenylephrine and bupivacaine-phenylephrine topical anesthetics compared with tetracaine-adrenaline-cocaine during repair of lacerations.

The effectiveness of two new topical anesthetics that do not contain cocaine (prilocaine-phenylephrine and bupivacaine-phenylephrine) was compared with that of tetracaine-adrenaline-cocaine (TAC) during laceration repair in children. This study was a prospective, randomized, double-blind trial conducted in the emergency department of a large children's hospital. Participants were 180 children 1 year of age or older with a laceration 5 cm or less in length that required suturing. Pain felt during suturing was scored by suture technicians, research assistants, parents, and patients 5 years of age and older using a visual analogue scale (VAS). There was no statistical difference demonstrated between the effectiveness of prilocaine-phenylephrine and that of TAC for any of the observer groups. A statistically significant difference was seen among anesthetics when comparing VAS scores of research assistants (P = .002), suture technicians (P = .006), and parents (P = .03), but not when comparing VAS ratings of patients (P = .07). Based on Tukey's post hoc test, these statistically significant differences were between TAC and bupivacaine-phenylephrine. When power analyses were performed using alpha = 0.05 and beta = 0.20, it was possible to detect a difference of 1.3 VAS units for each rater group. In conclusion, this study demonstrated the effectiveness and safety of prilocaine-phenylephrine and bupivacaine-phenylephrine. Prilocaine-phenylephrine statistically outperformed bupivacaine-phenylephrine and offers an effective alternative to TAC during laceration repair in children.

Adolescent↗
PubMed1998

Differentiation of CD4+ T cells to Th1 cells requires MAP kinase JNK2.

Precursor CD4+ T cells develop into effector Th1 and Th2 cells that play a central role in the immune response. We show that the JNK MAP kinase pathway is induced in Th1 but not in Th2 effector cells upon antigen stimulation. Further, the differentiation of precursor CD4+ T cells into effector Th1 but not Th2 cells is impaired in JNK2-deficient mice. The inability of IL-12 to differentiate JNK2-deficient CD4+ T cells fully into effector Th1 cells is caused by a defect in IFNgamma production during the early stages of differentiation. The addition of exogenous IFNgamma during differentiation restores IL-12-mediated Th1 polarization in the JNK2-deficient mice. The JNK MAP kinase signaling pathway, therefore, plays an important role in the balance of Th1 and Th2 immune responses.

Amino Acid Sequence↗
PubMed1998

Morbillivirus downregulation of CD46.

There is evidence that CD46 (membrane cofactor protein) is a cellular receptor for vaccine and laboratory-passaged strains of measles virus (MV). Following infection with these MV strains, CD46 is downregulated from the cell surface, and consequent complement-mediated lysis has been shown to occur upon infection of a human monocytic cell line. The MV hemagglutinin (H) protein alone is capable of inducing this downregulation. Some wild-type strains of MV fail to downregulate CD46, despite infection being prevented by anti-CD46 antibodies. In this study we show that CD46 is also downregulated to the same extent by wild-type, vaccine, and laboratory-passaged strains of rinderpest virus (RPV), although CD46 did not appear to be the receptor for RPV. Expression of the RPV H protein by a nonreplicating adenovirus vector was also found to cause this downregulation. A vaccine strain of peste des petits ruminants virus caused slight downregulation of CD46 in infected Vero cells, while wild-type and vaccine strains of canine distemper virus and a wild-type strain of dolphin morbillivirus failed to downregulate CD46. Downregulation of CD46 can, therefore, be a function independent of the use of this protein as a virus receptor.

Animals↗
PubMed1998

A conserved p38 mitogen-activated protein kinase pathway regulates Drosophila immunity gene expression.

Accumulating evidence suggests that the insect and mammalian innate immune response is mediated by homologous regulatory components. Proinflammatory cytokines and bacterial lipopolysaccharide stimulate mammalian immunity by activating transcription factors such as NF-kappaB and AP-1. One of the responses evoked by these stimuli is the initiation of a kinase cascade that leads to the phosphorylation of p38 mitogen-activated protein (MAP) kinase on Thr and Tyr within the motif Thr-Gly-Tyr, which is located within subdomain VIII. We have investigated the possible involvement of the p38 MAP kinase pathway in the Drosophila immune response. Two genes that are highly homologous to the mammalian p38 MAP kinase were molecularly cloned and characterized. Furthermore, genes that encode two novel Drosophila MAP kinase kinases, D-MKK3 and D-MKK4, were identified. D-MKK3 is an efficient activator of both Drosophila p38 MAP kinases, while D-MKK4 is an activator of D-JNK but not D-p38. These data establish that Drosophila indeed possesses a conserved p38 MAP kinase signaling pathway. We have examined the role of the D-p38 MAP kinases in the regulation of insect immunity. The results revealed that one of the functions of D-p38 is to attenuate antimicrobial peptide gene expression following exposure to lipopolysaccharide.

Amino Acid Sequence↗
PubMed1998

New approaches to the development of virus vaccines for veterinary use.

The marked progress in recombinant deoxyribonucleic acid (DNA) technology during the past decade has led to the development of a variety of safe new vaccine vectors which are capable of efficiently expressing foreign immunogens. These have been based on a variety of virus types--poxviruses, herpesviruses and adenoviruses--and have led to the production of many new potential recombinant vaccines. Of these recombinant vaccines, the rabies vaccine, in which the rabies G protein is expressed in a vaccinia vector, has been widely used in the field to prevent the spread of rabies both in Europe and in the United States of America. A recombinant Newcastle disease virus vaccine, using fowlpox virus as the vector to express immunogenic proteins from the Newcastle disease virus, has been licensed as the first commercial recombinant vectored vaccine. Many other recombinant virus vaccines are still at the stage of laboratory or field testing. The most recent breakthrough in vaccinology has been the success with the use of naked DNA as a means of vaccination. This approach has shown great promise in mouse model systems and has now become the most active field in new vaccine development. Molecular redesigning of conventional ribonucleic acid (RNA) viruses to obtain more stable attenuated vaccines was previously possible only for positive-strand RNA viruses, such as poliovirus. However, recent advances in molecular biological techniques have enabled the rescuing of negative-strand viruses from DNA copies of their genomes. This has made it possible to engineer specific changes in the genomes of Rhabdoviridae and Paramyxoviridae, both of which include several viruses of veterinary importance. The authors describe the current progress in the development of vector vaccines, DNA vaccines and vaccines based on engineered positive- and negative-strand RNA virus genomes, with special emphasis on their application to diseases of veterinary importance.

Adenoviridae↗
PubMed1997

Mitogen-activated protein kinase kinase 7 is an activator of the c-Jun NH2-terminal kinase.

The c-Jun NH2-terminal kinase (JNK) group of mitogen-activated protein (MAP) kinases is activated by phosphorylation on Thr and Tyr. Here we report the molecular cloning of a new member of the mammalian MAP kinase kinase group (MKK7) that functions as an activator of JNK. In vitro protein kinase assays demonstrate that MKK7 phosphorylates and activates JNK, but not the p38 or extracellular signal-regulated kinase groups of MAP kinase. Expression of MKK7 in cultured cells causes activation of the JNK signal transduction pathway. MKK7 is therefore established to be a novel component of the JNK signal transduction pathway.

Amino Acid Sequence↗
PubMed1997

The structure of the GTPase-activating domain from p50rhoGAP.

Members of the Rho family of small G proteins transduce signals from plasma-membrane receptors and control cell adhesion, motility and shape by actin cytoskeleton formation. They also activate other kinase cascades. Like all other GTPases, Rho proteins act as molecular switches, with an active GTP-bound form and an inactive GDP-bound form. The active conformation is promoted by guanine-nucleotide exchange factors, and the inactive state by GTPase-activating proteins (GAPs) which stimulate the intrinsic GTPase activity of small G proteins. Rho-specific GAP domains are found in a wide variety of large, multi-functional proteins. Here we report the crystal structure of an active 242-residue C-terminal fragment of human p50rhoGAP. The structure is an unusual arrangement of nine alpha-helices, the core of which includes a four-helix bundle. Residues conserved across the rhoGAP family are largely confined to one face of this bundle, which may be an interaction site for target G proteins. In particular, we propose that Arg 85 and Asn 194 are involved in binding G proteins and enhancing GTPase activity.

Amino Acid Sequence↗
PubMed1997

Risk factors for sporadic infection with Escherichia coli O157:H7.

BACKGROUND: Little is known about risk factors for sporadic infection with Escherichia coli O157:H7. In response to a sharp increase in reported cases in New Jersey during July 1994, we conducted a case-control study to identify principal sources of infection and contributing practices. METHODS: Standardized questionnaires were used to evaluate (1) potential exposures of case patients and matched controls and (2) knowledge, attitudes, and practices of food preparers in case and control households. Patient isolates were subtyped by pulsed-field gel electrophoresis. RESULTS: Patients with E coli O157:H7 infection (N = 23; median age, 9 years; 55% female) were more likely than healthy controls to have eaten a hamburger in the week preceding illness (matched odds ratio, undefined; P < .001); 80% of the hamburgers eaten by ill persons were prepared at home. Food preparers in case households were less likely than those in control households to report washing their hands (odds ratio, 8.5; P < .005) and work surfaces (odds ratio, 10.5; P < .05) after handling raw ground beef. Pulsed-field gel electrophoresis yielded 17 unique subtypes among the 23 patient isolates, indicating multiple sources of infection. CONCLUSIONS: Hamburgers prepared at home are an important source of sporadic E coli O157:H7 infections. We estimate that adequate hand washing by food preparers could have prevented 34% of E coli O157:H7 infections in the study population.

Adolescent↗
PubMed1997

Analysis of the haemagglutinin gene of current wild-type canine distemper virus isolates from Germany.

The haemagglutinin (H) gene sequences from three wild-type canine distemper viruses (CDV) isolated during 1994-1995 were sequenced to determine whether contemporary strains had undergone significant genetic changes relative to the currently used vaccine strains. The new isolates were closely related to each other (> 99%) and displayed about 90-91% sequence homology to the Onderstepoort and Convac vaccine strains. There were one to four additional potential glycosylation sites compared to the vaccine strains which were also present in a German dog CDV isolate dating from 1990. However, only a very slight reduction in neutralizing titre against the new isolates was found when compared with the Onderstepoort and Rockborn vaccine strains. Cysteine and proline residues were well conserved indicating a conserved three dimensional structure for the protein. By phylogenetic analysis the recent isolates showed a narrow clustering close to the previous canine isolates indicating a linear pattern of evolutionary changes. A comparison with published CDV H gene sequences suggested the presence of different lineages of CDV on a global scale and possible cocirculation of more than one genotype of CDV.

Amino Acid Sequence↗
PubMed1997

Trial of a capripoxvirus-rinderpest recombinant vaccine in African cattle.

Cattle were vaccinated with differing doses of an equal mixture of capripox-rinderpest recombinant viruses expressing either the fusion protein (F) or the haemagglutinin protein (H) of rinderpest virus. Animals vaccinated with 2 x 10(4) p.f.u. or greater of the combined viruses were completely protected against challenge, 1 month later, with both virulent rinderpest and lumpy skin disease viruses. Vaccination with any of the doses did not induce any adverse clinical response in the animals or transmission of the vaccine virus between animals. All cattle challenged 6 or 12 months after vaccination with 2 x 10(5) p.f.u. of the mixture of recombinant viruses were protected from severe rinderpest disease. Ten out of 18 were completely protected while the remaining 8 developed mild clinical signs of rinderpest. Cattle vaccinated with the recombinant vaccines after prior infection with the parental capripox virus showed more marked clinical signs of rinderpest after challenge with virulent rinderpest, but 9 out of 10 recovered, compared with 80% mortality in the unvaccinated controls.

Animals↗
PubMed1997

Localization of the gene for thiamine-responsive megaloblastic anemia syndrome, on the long arm of chromosome 1, by homozygosity mapping.

Thiamine-responsive megaloblastic anemia, also known as "TRMA" or "Rogers syndrome," is an early-onset autosomal recessive disorder defined by the occurrence of megaloblastic anemia, diabetes mellitus, and sensorineural deafness, responding in varying degrees to thiamine treatment. On the basis of a linkage analysis of affected families of Alaskan and of Italian origin, we found, using homozygosity mapping, that the TRMA-syndrome gene maps to a region on chromosome 1q23.2-23.3 (maximum LOD score of 3.7 for D1S1679). By use of additional consanguineous kindreds of Israeli-Arab origin, the putative disease-gene interval also has been confirmed and narrowed, suggesting genetic homogeneity. Linkage analysis generated the highest combined LOD-score value, 8.1 at a recombination fraction of 0, with marker D1S2799. Haplotype analysis and recombination events narrowed the TRMA locus to a 16-cM region between markers D1S194 and D1S2786. Several heterozygote parents had diabetes mellitus, deafness, or megaloblastic anemia, which raised the possibility that mutations at this locus predispose carriers in general to these manifestations. Characterization of the metabolic defect of TRMA may shed light on the role of thiamine deficiency in such common diseases.

Alaska↗