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Biomedical subjects

G Lawrence

Publications and source records attributed to G Lawrence.

At least 37 records · Page 2Linked to original sources
PubMed1999

Human phase I vaccine trials of 3 recombinant asexual stage malaria antigens with Montanide ISA720 adjuvant.

Two phase I vaccine trials were conducted to test the immunogenicity and safety of a vaccine containing three recombinant malaria antigens from the asexual stage of Plasmodium falciparum. The three antigens are a fragment of MSP1 (190LCS.T3); MSP2 and a portion of RESA and were formulated in Montanide ISA720 adjuvant. These trials investigated the dose response of each antigen for eliciting both antibody and T-cell responses and the immunogenicity of a mixture of the antigens compared with the antigens injected separately. All three antigens elicited both antibody and T-cell responses. Strong T-cell responses were observed with 190LCS.T3 and RESA with stimulation indices exceeding 100 for peripheral blood leucocytes in some individuals. The antibody responses were generally weak. The human antibody responses observed with MSP2 in Montanide ISA720 were not significantly different from those obtained in an earlier trial which used MSP2 with alum as the adjuvant. No antigenic competition was observed: volunteers receiving a mixture of antigens had similar responses to those receiving the three antigens at separate sites. Tenderness and pain at the injection site were common over the first few days following immunization. In some volunteers, especially those receiving the highest doses tested, there was a delayed reaction at the injection site with pain and swelling occurring approximately 10 days after injection.

Adjuvants, Immunologic↗
PubMed1998

Effects of a peptide analogue of the amphiphilic domain of the common neurotrophin receptor on nerve growth factor-mediated motility of human neuroblastoma cells.

Exposure of human neuroblastoma cells (IMR-32) to a peptide mimic of the cytoplasmic amphiphilic domain of the common neurotrophin receptor (p75NTR 367-379) resulted in enhanced nerve growth factor (NGF)-mediated inhibition of cell invasion in vitro. The peptide also enhanced NGF-mediated neurite extension and GAP-43 gene expression but had no effect on NGF-mediated cell survival. These latter functional effects mimicked influences on NGF-mediated neurite growth in other trkA-positive cells as reported previously. NGF-dependent trkA phosphorylation was significantly enhanced by the presence of the peptide, whereas high-affinity binding of 125I-NGF, both NGF receptors mRNA and protein expression, and trkA dimer/monomer ratios were not influenced. The studies suggest that ligand-mediated trkA activation has differential effects on cell motility phenomena and that the amphiphilic domain of p75NTR has a role in this differential signaling.

Cell Movement↗
PubMed1998

School-based management of chronic asthma among inner-city African-American schoolchildren in Dallas, Texas.

Asthma, a chronic disease of the respiratory tract, affects approximately five percent of the U.S. population, including almost five million children. Childhood asthma has been identified as the leading cause of school absences. This study was to examined efficacy of a school-based program to prevent exacerbation of asthma symptoms and manage asthma in school children using measured doses of an inhaled anti-inflammatory medication. The sample consisted of 22 African-American children in one inner-city elementary school in Dallas, Texas, ages 5-12 years with confirmed diagnoses of asthma. For three months, each child came to the school clinic two times per day for medication administration and measurement of respiratory peak flow rates. Data were collected for a number of variables including bronchodilator use, school absences, self-report of asthma symptoms, and number of visits to the physician. During the study, mean peak flow rates improved approximately 15%, and bronchodilator use decreased 66%. Improvement also was evident in several other areas.

Absenteeism↗
PubMed1998

Axillary dissection in invasive breast cancer.

For patients with tumors > 2 cm (clinical T2-3 N0 M0), the tumor's virulence and metastatic potential are evident without further invasive or noninvasive tests. These patients would be better served with treatment ot the local, regional, and systematic components of the disease. For patients with T1 N0 M0 tumors, such information as tumor size, grade, receptor status, and results of noninvasive tests may help separate the two extremes for which axillary dissection will not affect decisions about adjuvant therapy. In the subset of patients in whom axillary dissection will define adjuvant therapy, sentinel node biopsy should definitely be performed. For metastases, nodal radiation would be therapeutic, together with systemic therapy. Axillary dissection is recommended for patients with palpable axillary disease.

Biopsy↗
PubMed1997

Measurement of Plasmodium falciparum growth rates in vivo: a test of malaria vaccines.

Several prototype vaccines against the asexual blood stage of malaria are undergoing preclinical and phase I testing. Although these vaccines have been chosen for their ability to elicit an anti-parasite response, no practical and sensitive clinical trial procedure has been available for measuring their impact on parasite growth. We describe a system that allows parasite growth rates to be measured in volunteers through the incubation period. Two necessary elements of this system are developed: suitable blood-stage Plasmodium falciparum inocula, and a highly sensitive and quantitative assay to measure parasite growth during the incubation period. We infected five nonimmune volunteers with an inoculum as small as 300 parasites and demonstrated that the resultant in vivo asexual parasite growth rates were reproducible at 12-15-fold per cycle. The system allowed the infection to be followed for eight days before treatment without symptoms developing. These findings suggest that it is feasible to directly measure the anti-parasite efficacy of a prototype malaria vaccine in human volunteers without subjecting them to the risk of disease.

Adult↗
PubMed1996

Experimental human Plasmodium falciparum infections: longitudinal analysis of lymphocyte responses with particular reference to gamma delta T cells.

The kinetics of the gamma delta T-cell response was analysed in the context of the overall haematological response in subjects experimentally infected with sporozoites of Plasmodium falciparum. Numbers of gamma delta and alpha beta T cells and NK cells declined markedly during infection to reach minimum values 12-13 days post-infection when the patients were ill. This decline commenced from the beginning of the erythrocytic cycle and well before parasites could be detected microscopically and clinical symptoms developed. Platelet numbers also declined. In vivo activation of gamma delta T cells was evident with sequential up-regulation of the activation markers CD69 and HLA-DR. gamma delta T cell numbers were highest after treatment with the majority being CD4-CD8-, HLA-DR+ and showing reduced CD45RA expression. Contrary to some published observations gamma delta T-cell percentages remained within the normal range. Little evidence of upregulation of activation or memory markers was observed in the alpha beta T-cell population. In vitro proliferative responses to malaria antigen which involve gamma delta T cells were lost as the infection progressed and the lymphocyte count declined but these could be restored with the addition of exogenous IL-2 to cultures. The authors findings are consistent with a protective and/or immunomodulatory role for gamma delta T cells in malaria.

Adult↗