Biomedical subjects

David Wade

Publications and source records attributed to David Wade.

10 recordsLinked to original sources

PubMed2006

Development of a benthic index to assess sediment quality in the Tampa Bay Estuary.

The identification, remedial treatment, and monitoring of contaminated sediments are among the priorities for managers of the Tampa Bay Estuary. Tampa Bay, as an urbanized estuary, is subject to the input of watershed sources of chemical contaminants, including metals, pesticides, and organic chemicals. Although the use of biological indicators and their incorporation into multi-metric indices is not new, the refinement and applications of such techniques for determining environmental condition still require further development and exploration. We present a single Tampa Bay Benthic Index (TBBI) that was developed specifically for Tampa Bay. Stepwise discriminant analysis was applied to a comprehensive list of potential benthic metrics. Results from the stepwise procedure identified the metrics that best discriminated between "healthy" and "degraded" conditions, as defined by sediment contaminant effect levels and dissolved oxygen. Discriminant analysis was then applied to the resultant three variables to determine the linear combination for the index.

Animals↗

PubMed2006

Inhibition of Bacillus anthracis and potential surrogate bacilli growth from spore inocula by nisin and other antimicrobial peptides.

The ability of nisin, synthetic temporin analogs, magainins, defensins, and cecropins to inhibit Bacillus anthracis, Bacillus cereus, Bacillus thuringiensis, Bacillus mycoides, and Bacillus subtilis growth from spore inocula was determined using well diffusion assays. Nisin, magainin II amide, and defensins were inhibitory in screening against B. anthracis Sterne or B. cereus ATCC 7004, but only nisin inhibited virulent B. anthracis strains. The MICs of nisin against the 10 Bacillus strains examined were 0.70 to 13.51 microg/ml. Synthetic temporin analogs also inhibited B. anthracis but were not as potent as nisin. None of the strains examined were appropriate B. anthracis surrogates for testing sensitivity to antimicrobial peptides.

Anti-Bacterial Agents↗

PubMed2005

Antimicrobial peptides from amphibian skin potently inhibit human immunodeficiency virus infection and transfer of virus from dendritic cells to T cells.

Topical antimicrobicides hold great promise in reducing human immunodeficiency virus (HIV) transmission. Amphibian skin provides a rich source of broad-spectrum antimicrobial peptides including some that have antiviral activity. We tested 14 peptides derived from diverse amphibian species for the capacity to inhibit HIV infection. Three peptides (caerin 1.1, caerin 1.9, and maculatin 1.1) completely inhibited HIV infection of T cells within minutes of exposure to virus at concentrations that were not toxic to target cells. These peptides also suppressed infection by murine leukemia virus but not by reovirus, a structurally unrelated nonenveloped virus. Preincubation with peptides prevented viral fusion to target cells and disrupted the HIV envelope. Remarkably, these amphibian peptides also were highly effective in inhibiting the transfer of HIV by dendritic cells (DCs) to T cells, even when DCs were transiently exposed to peptides 8 h after virus capture. These data suggest that amphibian-derived peptides can access DC-sequestered HIV and destroy the virus before it can be transferred to T cells. Thus, amphibian-derived antimicrobial peptides show promise as topical inhibitors of mucosal HIV transmission and provide novel tools to understand the complex biology of HIV capture by DCs.

Amino Acid Sequence↗

PubMed2004

Temporin A and related frog antimicrobial peptides use formyl peptide receptor-like 1 as a receptor to chemoattract phagocytes.

Many mammalian antimicrobial peptides (AMPs) have multiple effects on antimicrobial immunity. We found that temporin A (TA), a representative frog-derived AMP, induced the migration of human monocytes, neutrophils, and macrophages with a bell-shaped response curve in a pertussis toxin-sensitive manner, activated p44/42 MAPK, and stimulated Ca(2+) flux in monocytes, suggesting that TA is capable of chemoattracting phagocytic leukocytes by the use of a G(ialpha) protein-coupled receptor. TA-induced Ca(2+) flux in monocytes was cross-desensitized by an agonistic ligand MMK-1 specific for formyl peptide receptor-like 1 (FPRL1) and vice versa, suggesting that TA uses FPRL1 as a receptor. This conclusion was confirmed by data showing that TA selectively stimulated chemotaxis of HEK 293 cells transfected with human FPRL1 or its mouse ortholog, murine formyl peptide receptor 2. In addition, TA elicited the infiltration of neutrophils and monocytes into the injection site of mice, indicating that TA is also functionally chemotactic in vivo. Examination of two additional temporins revealed that Rana-6 was also able to attract human phagocytes using FPRL1, but temporin 1P selectively induced the migration of neutrophils using a distinct receptor. Comparison of the chemotactic and antimicrobial activities of several synthetic analogues suggested that these activities are likely to rely on different structural characteristics. Overall, the results demonstrate that certain frog-derived temporins have the capacity to chemoattract phagocytes by the use of human FPRL1 (or its orthologs in other species), providing the first evidence suggesting the potential participation of certain amphibian antimicrobial peptides in host antimicrobial immunity.

Animals↗

PubMed2003

Activities of temporin family peptides against the chytrid fungus (Batrachochytrium dendrobatidis) associated with global amphibian declines.

Temporin A and structurally related peptides produced in amphibian dermal granular glands and in wasp venom were tested for growth inhibition of Batrachochytrium dendrobatidis, a pathogen associated with global amphibian declines. Two natural amphibian temporins, a wasp temporin, and six synthetic analogs effectively inhibited growth. Differences in potency due to amino acid substitution suggest that ability to penetrate membranes and form an alpha-helical structure is important for their effectiveness against this pathogen.

Amino Acid Substitution↗

PubMed2002

Nobel women.

Explore the source record for details and available documents.

Female↗

PubMed2002

A survey of a novel epilepsy clinic.

The management of a group of epilepsy patients from primary care, in a geographical area with clear epilepsy management guidelines and secondary care clinics is surveyed. Suggestions are made to improve liaison between primary and secondary care as well as epilepsy management in primary care. All 42 local primary care practices were invited to take part in this project. A study day providing a broad overview of epilepsy management was held. Those attending were expected to identify all patients in their practice with epilepsy using diagnostic codes and prescribing data. Nine of the invited 42 practices took part in the project, and identified 506 patients prescribed anti-epilepsy drugs (AEDs). Three hundred and three patients were invited for review by their practice nurse, following exclusion of those prescribed AEDs for other conditions, children and those already under specialist review. One hundred and sixteen patients attended for review. Seventy-one patients were identified as requiring specialist review and a consultant neurologist, epilepsy nurse specialist and clinical assistant completed them. Of the 71 patients 31 had experienced no seizures for 5 years, 40 had experienced seizures in the past 5 years, of whom 32 had experienced seizures in the last year. Sixteen were suffering at least one seizure per month, and a few had poorly controlled epilepsy. Patients were taking mainly Phenytoin, Carbamazepine and Sodium valproate. Twenty were taking polytherapy and one no treatment.Fifty-two patients reported side effects and 15 poor compliance. Many patients reviewed were considered to be taking unnecessary medication and suffering unnecessary side effects. There is a need for improved epilepsy management in primary care and better liaison between primary and secondary care.

Adult↗

PubMed2002

Antibiotic properties of novel synthetic temporin A analogs and a cecropin A-temporin A hybrid peptide.

Temporin A, 18 analogs, and a cecropin A-temporin A hybrid peptide were tested with antibiotic sensitive and resistant bacteria, fungi, human erythrocytes, and in clotting assays. Several peptides were active in these assays, and some analogs (D-TA, W1-TA, and Con-L4,G10) may be useful lead compounds for further antibiotics development. The activity of temporin A was found to be dependent upon several of its structural features, including amino acid composition and sequence, chirality, helicity, and positive charge.

Anti-Bacterial Agents↗

PubMed2002

Synthetic antibiotic peptides database.

A computerized database for synthetic antibiotic peptides, the SAPD, has been created and is available on the Internet at web address, http://oma.terkko.helsinki.fi:8080/~SAPD. The SAPD is modelled on two pre-existing computer databases for naturally occurring peptide antibiotics, the Antimicrobial Sequences Database and the Peptaibol Database, and it will contain both chemical and biological information on all published synthetic antibiotic peptides.

Anti-Bacterial Agents↗

PubMed1998

Antianaerobic activity of a cecropin---melittin peptide.

OBJECTIVE: Several small, 15-residue peptides that contain portions of the amino acid sequences of both cecropin A and melittin have previously been shown to have broad-spectrum antibacterial activities against aerobic microorganisms, with no undesirable hemolytic properties. It would also be useful to know what effect these hybrid peptides have on anaerobic bacteria. METHODS: The minimum inhibitory concentrations of one hybrid, CA(1--7)M(2--9)NH2, were compared with those of seven other antimicrobial agents against 111 clinical anaerobic strains; Bacteroides fragilis, 24 strains; other Bacteroides fragilis group, 14 strains; other Bacteroides species, 13 strains; Fusobacterium nucleatum, six strains; Clostridium difficile, 22 strains; Clostridium perfringens, 10 strains, Propionibacterium spp., nine strains; and anaerobic cocci, 13 strains. RESULTS: Ninety per cent of strains belonging to the B. fragilis group, fusobacteria, propionibacteria and peptostreptococci were inhibited by 4 mg/L CA(1--7)M(2--9)NH2, and the antimicrobial activity was approximately in the same range as that of chloramphenicol. CONCLUSION: This investigation showed that the antimicrobial spectrum of this cecropin---melittin hybrid also includes anaerobic organisms.

Journal Article↗