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Biomedical subjects

B Peck

Publications and source records attributed to B Peck.

17 recordsLinked to original sources
PubMed2001

Characterization of four members of a multigene family encoding outer membrane proteins of Helicobacter pylori and their potential for vaccination.

In search of protective antigens which can be used in a vaccine to prevent Helicobacter pylori infection, we report on the identification of four genes, hopV, hopW, hopX and hopY, and the characterization of the corresponding proteins which belong to the H. pylori outer membrane protein (Hop) family containing 32 homologous members, some of which were shown to function as porins. Sequence analysis of 16 different H. pylori strains revealed that the proteins HopV, HopW, HopX and HopY are highly conserved. Localization of HopV, HopW, HopX and HopY at the surface of the bacteria was investigated by immunofluorescence. Using a planar lipid bilayer system the proteins HopV and HopX were shown to form pores with single-channel conductances of 1.4 and 3.0 nS, respectively.

Amino Acid Sequence↗
PubMed1999

Conservation, localization and expression of HopZ, a protein involved in adhesion of Helicobacter pylori.

From a sarkosyl-insoluble outer membrane fraction prepared from the Helicobacter pylori strain ATCC 43504, 19 proteins could be sequenced N-terminally by Edman degradation. Oligonucleotides were deduced and used for screening of a genomic library. From the isolated genes, five code for different members of a H.pylori outer membrane protein (Hop) family. Among these, the hopZ gene was characterized in more detail. It encodes a protein which was shown to be located at the bacterial surface by immunofluorescence studies. Sequence analysis of the hopZ gene from 15 different H.pylori strains revealed the existence of two alleles and the possible regulation of hopZ expression by slipped-strand mispairing within a CT dinucleotide repeat motif located in the signal-peptide coding region. Among the different strains, the influence of this region on the expression of HopZ was analyzed on a translational level by western blot analysis of bacterial extracts and immunofluorescence studies on intact cells. The protein is expressed only in those strains in which the number of the CT dinucleotide repeats allow for an open reading frame encoding the complete protein. Addionally the function of HopZ was investigated in an adhesion assay. The wild-type strain ATCC 43504 adhered to human gastric epithel cells whereas a knockout mutant strain showed significantly reduced binding to the cells.

Alleles↗
PubMed1999

Engraftment of gene-marked hematopoietic progenitors in myeloma patients after transplant of autologous long-term marrow cultures.

We conducted a phase I hematopoietic stem cell (HSC) gene-marking trial in patients undergoing autologous blood or marrow stem cell transplant for the treatment of multiple myeloma. Between 500 and 1000 ml of bone marrow was harvested from each of 14 myeloma patients and 1 syngeneic donor. A mean of 3.3x10(9) cells per patient were plated in 20 to 50 long-term marrow culture (LTMC) flasks and maintained for 3 weeks. LTMCs were exposed on days 8 and 15 to clinical-grade neo(r)-containing retrovirus supernatant (G1Na). A mean of 8.23x10(8) day-21 LTMC cells containing 5.2x10(4) gene-marked granulocyte-macrophage progenitor cells (CFU-GM) were infused along with an unmanipulated peripheral blood stem cell graft into each patient after myeloablative therapy. Proviral DNA was detected in 71% of 68 tested blood and bone marrow samples and 150 of 2936 (5.1%) CFU-GM derived from patient bone marrow samples after transplant. The proportion of proviral DNA-positive CFU-GM declined from a mean of 9.8% at 3 months to a mean of 2.3% at 24 months postinfusion. Southern blots of 26 marrow and blood samples were negative. Semiquantitative PCR analysis indicated that gene transfer was achieved in 0.01-1% of total bone marrow and blood mononuclear cells (MNCs). Proviral DNA was also observed in EBV-transformed B lymphocytes, in CD34+ -enriched bone marrow cells, and in CFUs derived from the latter progenitors. Gene-modified cells were detected by PCR in peripheral blood and bone marrow for 24 months after infusion of LTMC cells. Sensitivity and specificity of the PCR assays were independently validated in four laboratories. Our data confirm that HSCs may be successfully transduced in stromal based culture systems. The major obstacle to therapeutic application of this approach remains the overall low level of genetically modified cells among the total hematopoietic cell pool in vivo.

Bone Marrow Cells↗
PubMed1998

Rheumatoid arthritis. Early intervention can change outcomes.

Rheumatoid arthritis (RA) is an autoimmune disease with a predilection for synovial tissues, although it can affect other organs. Although the precise etiology is uncertain, viruses, genetics, immune dysfunction and physical trauma have all been implicated as causes for RA. The most basic definition, therefore, is that RA is inflammatory. The RA patient may have difficulty closing a fist or may have a week grip. The late stages of RA are easy to identify by X-ray, but to really perform a service for a patient, you must be able to identify its early stages. To do this, you must be able to examine joints. If a patient does not have a history of liver disease or heavy alcohol intake, methotrexate is the first treatment choice except in the very mildest of cases, when you can use NSAIDs. Steroids are sometimes an essential treatment, but use them with great caution and pay attention to the minimum effective dose.

Arthritis, Rheumatoid↗
PubMed1995

Conformational flexibility in DNA duplexes containing single G.G mismatches.

Purine-purine mismatches can base-pair in a variety of configurations depending on solution conditions. The G.G mismatch, which also occurs in the G-quartet structure, has been shown by both x-ray crystallography and NMR to adopt G(anti).G(syn) mispairs, with very different hydrogen bonding patterns [Skelly, J., Edwards, K., Jenkins, T. C. & Neidle, S. (1993) Proc. Natl Acad. Sci. USA 90, 804-808; Cognet, J. A. H., Gabarro-Arpa, J., Le Bret, M., van der Marel, G. A. van Boom, J. H. & Fazakerley, G. V. (1991) Nucleic Acids. Res. 19, 6771-6779] while we have recently suggested the presence of weakly hydrogen-bonded G(anti).G(anti) pairs in solution [Borden, K. L. B., Jenkins, T. C., Skelly, J. V., Brown, T. & Lane, A. N. (1992) Biochemistry 31, 5411-5422]. Spectral overlap and additional exchange processes have made detailed structural analysis difficult in these mismatched oligomers. We have used NMR to characterise the conformations of four duplexes containing single G.G mismatches, including a nonamer d(CATCGGATG), two undecamers d(GCATTGAATGC) and d(CATGTGACGTG) that can each form a self-complementary duplex with a single G.G mispair in the centre, and the non-self-complementary d(GTAACGACATG).d(CATGTGGTTAC). The three self-complementary duplexes have a single set of NMR resonances, and all four duplexes show evidence of conformational exchange at the mismatch site. The N1H resonances of the mismatched G residues each integrate to two protons, ruling out the enol tautomer. They resonate between 10.5-10.7 ppm, far upfield of the Watson-Crick hydrogen-bonded GN1H and exchange readily with water protons. Intraresidue GH8-H1' NOE intensities are two-threefold larger for the mismatched G residues than in G.C base pairs, indicating the presence of syn conformations. NOE time courses for the self-complementary duplexes were consistent with an equimolar mixture of G(syn).G(anti) and G (anti).G(syn) states. By symmetry, these states must be interconverting at a rate that is fast on the chemical shift timescale. In the non-self-complementary undecamer, the NOE data indicated that the distinguishable mismatched G residues also spend a significant, but different, fraction of the time in both the syn and anti conformations. The rate constant for the syn/anti transition in the non-self-complementary undecamer was determined as approximately 14,000 s-1 at 303 K from rotating frame T1 measurements, and the apparent frequency difference was > 250 Hz. Calculations based on NOEs and coupling constants showed that the duplexes are overall in the B form.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1991

Insomnia in the elderly.

Insomnias lead the list of sleep disorders in the elderly. The differential diagnosis includes poor sleep habits, medical and psychiatric disorders, and drug interactions. Effective treatment includes sleep hygiene education and avoidance of substances known to interfere with sleep. In general, anticholinergic agents, antihistamines and long-half-life benzodiazepines should be avoided as hypnotic agents in the elderly. Safer therapeutic options include relaxation therapy and the short-half-life benzodiazepines without active metabolites.

Aged↗
PubMed1989

Visual superiority effect in televised prevention of victimization programs for preschool children.

Preschool children have been reported to remember more visual than auditory content from television programs. 80 preschool children were randomly assigned to conditions where visual or auditory components of a televised program on personal safety were manipulated. Visually modeled actions were slightly more salient for preschool-age children than actions represented auditorily. The combination of visual and auditory input provided the superior educational method.

Attention↗
PubMed1979

Effects of childhood cancer on long-term survivors and their families.

Problems experienced by families of long-term survivors of acute lymphatic leukaemia and Wilms's tumour were investigated to find out the best way of using limited resources to improve management of such patients. All patients had received treatment at Alder Hey Children's Hospital, and all had completed treatment at least two years before the study. A social worker interviewed the parents of each child. The results showed that various aspects of management needed improvement, including: information given to parents at diagnosis of their child's illness and during subsequent treatment; continuity of care and multidisciplinary teamwork among those caring for the child; greater understanding by school teachers that such children have the same educational needs as others; wider communication by hospital staff with the child's other relatives, particularly grandparents; financial help for parents; and marital counselling. To help implement these proposals full-time social workers were attached to the hospital. Preliminary results were encouraging, though it is too early to evaluate the long-term effects of the changes.

Adolescent↗
PubMed1978

Thrombophlebitis in systemic lupus erythematosus.

Thrombophlebitis occurred in 14 (12.2%) of 114 patients with active systemic lupus erythematosus (SLE). Abnormal clotting occurred despite the presence of thrombocytopenia or circulating anticoagulants in some of the patients, and the development of pulmonary emboli was verified in seven. Although infrequently reported, the association of thrombophlebitis with active SLE is apparently not uncommon. While there were no features that distinguished this group of patients from other groups of patients with SLE, there are some possible mechanisms. Recognition of this complication of SLE is important because of the frequent occurrence of SLE-induced pleuritis and its similarity to the pain of pulmonary emboli.

Adolescent↗
PubMedDate not supplied

Screening-level ecological risk assessment of polychlorinated dibenzo-p-dioxins and dibenzofurans in sediments and aquatic biota from the Venice Lagoon, Italy.

Recent monitoring data indicate that portions of Italy's Venice Lagoon ecosystem have been degraded due to biological and chemical pollution from a variety of potential sources. Using polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) data collected from sediment, fish and shellfish in the Lagoon, a screening-level ecological risk assessment (ERA) was performed to evaluate the risks to representative aquatic biota and wildlife receptors. Risks to aquatic invertebrates posed by PCDD/Fs in sediment were evaluated by comparing measured tissue concentrations in fish and shellfish to appropriate ecotoxicological reference values. For mammalian and avian receptors, risks posed by theoretical exposures to PCDD/Fs through the food chain were calculated using conservative wildlife exposure models. Results of the screening-level approach indicate that the potential for adverse effects to fish and aquatic invertebrate receptors from PCDD/Fs in surficial sediments are unlikely. Adverse effects to wildlife are possible but highly uncertain, and warrants further investigation in a more comprehensive ERA.

Animals↗