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Biomedical subjects

J A Price

Publications and source records attributed to J A Price.

At least 37 records · Page 2Linked to original sources
PubMed1998

Identification of a mutation in DLX3 associated with tricho-dento-osseous (TDO) syndrome.

Tricho-dento-osseous syndrome (TDO) is an autosomal dominant disorder characterized by abnormal hair, teeth and bone. The main clinical manifestations of TDO include taurodontism, enamel hypoplasia, kinky, curly hair at birth and increased thickness and density of the cranial bones. These pleiotropic clinical features suggest the role of a developmental gene modulating epithelial-mesenchymal interactions. We recently mapped the TDO locus to chromosome 17q21, a region that includes two members of the distal-less homeobox gene family, DLX3 and DLX7. In this paper we describe genomic cloning and sequencing of both human DLX3 and DLX7 and identification of a 4 bp deletion in human DLX3 which correlates with the TDO phenotype in six families. The observed mutation is predicted to cause a frameshift and premature termination codon, resulting in a functionally altered DLX3. This first report of a human mutation in the DLX genes is consistent with murine studies indicating their important role in the development of hair, teeth and bone.

Abnormalities, Multiple↗
PubMed1998

A common DLX3 gene mutation is responsible for tricho-dento-osseous syndrome in Virginia and North Carolina families.

Tricho-dento-osseous syndrome (TDO) is characterised by a variable clinical phenotype primarily affecting the hair, teeth, and bone. Different clinical features are observed between and within TDO families. It is not known whether the variable clinical features are the result of genetic heterogeneity or clinical variability. A gene for TDO was localised recently to chromosome 17q21 in four North Carolina families, and a 4 bp deletion in the human distal-less 3 gene (DLX3) was identified in all affected members. A previous genetic linkage study in a large Virginia kindred with TDO indicated possible linkage to the ABO, Gc, and Kell blood group loci. To examine whether TDO exhibits genetic heterogeneity, we have performed molecular genetic analysis to determine whether affected members of this Virginia kindred have the DLX3 gene deletion identified in North Carolina families. Results show that affected subjects (n=3) from the Virginia family have the same four nucleotide deletion previously identified in the North Carolina families. A common haplotype for three genetic markers surrounding the DLX3 gene was identified in all affected subjects in the North Carolina and Virginia families. These findings suggest that all people with TDO who have been evaluated have inherited the same DLX3 gene deletion mutation from a common ancestor. The variable clinical phenotype observed in these North Carolina and Virginia families, which share a common gene mutation, suggests that clinical variability is not the result of genetic heterogeneity at the major locus, but may reflect genetic heterogeneity at other epigenetic loci or contributing environmental factors or both.

Abnormalities, Multiple↗
PubMed1997

Analysis of antibody-antigen interactions using size-exclusion high-performance (pressure) liquid chromatography.

The development of methods to measure avidity of anti-sera reacting to antigen in solution using size-exclusion high-performance (pressure) liquid chromatography (SE-HPLC) was initiated using a model system composed of human serum albumin (HSA) and mouse anti-HSA IgG (mIgG). Mixtures containing varying concentrations of mIgG and HSA (mIgG, 0-2.4 microM, and HSA, 3.2 microM; mIgG, 0.80 microM, and HSA, 0-6.3 microM) were incubated for 1 h at 37 degrees C. Mixture components were separated using a Bio-Sil TSK 250 size exclusion column (300 x 7.5 mm) equilibrated with 0.05 m sodium phosphate buffer (pH 6.8) containing 0.1 m sodium sulfate. Four separate peaks containing either HSA, mIgG, an intermediate molecular weight complex (C1) or a high-molecular-weight complex (C2) could be identified from the elution profiles at 280 nm. Plots of peak areas versus initial mIgG or HSA concentrations could be modeled mathematically using equations from the law of mass action. Apparent binding constants (1.1 x 10(7) to 5.2 x 10(7) liters/mol) and stoichiometry of binding are consistent with that reported in the literature.

Algorithms↗
PubMed1997

Microplate assay for measurement of histamine release from mast cells.

A microplate-format assay for measurement of histamine release by activated rat peritoneal mast cells, with accompanying microplate-format spectrofluorometric assay of histamine, is demonstrated. Reproducibility and linearity of the histamine assay are comparable to the historical large format assay. Transfer of samples in the 96-well format, from histamine release through spectrofluorometric assay, greatly expedites handling and provides for better independence of each replicate. A sample experiment is included to show a typical size experiment easily done in this format.

Animals↗
PubMed1995

Activation of class II MHC genes requires both the X box region and the class II transactivator (CIITA).

CIITA, a gene that can complement a transcriptional mutation of the major histocompatibility complex (MHC) class II genes, was tested for its ability to function as a coactivator, CIITA cDNA clones isolated showed alternative RNA splicing, but only one splice site combination was able to restore class II MHC gene expression. DNA-mediated transfection experiments showed that CIITA directs its activity through the X box element; the presence of CIITA leads to the formation of a higher order complex at the X box region; and CIITA contains a potent activation domain. These findings support the hypothesis that CIITA directly interacts with the MHC class II-specific transcription factors and is required for expression.

Alternative Splicing↗
PubMed1993

An M protein with a single C repeat prevents phagocytosis of Streptococcus pyogenes: use of a temperature-sensitive shuttle vector to deliver homologous sequences to the chromosome of S. pyogenes.

The major virulence factor of the important human pathogen Streptococcus pyogenes is the M protein, which prevents phagocytosis of the bacterium. In different strains of streptococci, there are over 80 serologically different M proteins and there are additional M-like proteins, some of which bind immunoglobulins. Although the sequence of the M molecules differs among different S. pyogenes strains, all M proteins, and some of the immunoglobulin-binding molecules, have at least two copies of the C repeat region. We describe construction of a deletion mutation in S. pyogenes, which has only one C repeat copy, and show that the mutant strain is still resistant to phagocytosis. The mutation was constructed in vitro and used to replace the resident emm allele in an S. pyogenes strain. To facilitate homologous recombination into the streptococcal chromosome, we adapted a shuttle vector which is temperature sensitive for replication in Gram-positive bacteria but not in Gram-negative hosts. This new method for delivery of a homologous DNA fragment to the S. pyogenes chromosome is efficient and reproducible and should be of general use.

Alleles↗
PubMed1992

Bacteriophage phi X-174 as an aerobiological marker for surgical plume generated by the electromagnetic field focusing system.

The aerosol of surgical plume could be measured effectively with the use of bacteriophage phi X-174 as a biological marker, in contrast to previous methodologies reported by others. Recovery of virus plaque-forming units was highest from hydrophobic polytetrafluoro-ethylene membranes compared to hydrophobic polycarbonate screen filters or polyvinylidene difluoride depth filters, indicating that the method of virus recovery strongly affects the utility of a virus as an aerobiological marker. With this new method, surgical plume was indeed found in significant amounts when cutting tissue phantoms made with agar containing virus. The Electromagnetic Field Focusing System was used, which is a new thermal surgical device. The nominal power setting did not appear to be a factor in the amount of virus recovered. However, when pulse modulating the power by adjusting the crest factor from 1.4 to 4.3, a measure of the duty cycle for power delivery which adjusted the device from its cutting to haemostatic mode, a nearly five-fold increase in surgical plume, as evidence by the recovery of phi X-174 plaque forming units, was seen. The data indicate that bacteriophage phi X-174 can be used effectively as an aerobiological marker for aerosols generated during clinical procedures, and reinforce the need to use a safety vacuum during aerosol generating procedures. The availability of a safe and economical biological marker for aerosols from clinical procedures, which may lead to acquired infections in hospital personnel, makes evaluation of procedures and containment systems markedly easier. The data also indicates that surgical plume biohazard may be present in other techniques that employ pulse modulation including surgical lasers and electrocauteries.

Aerosols↗
PubMed1991

Melanoma tumor vaccine: five-year follow-up.

For many years, various melanoma vaccines have been employed. This is a unique melanoma vaccine in that it is a subcellular tumor homogenate and no adjuvants have been added. This vaccine has been given to 129 stage I and 61 stage II melanoma patients. All were followed at least 5 years and had 87.5% and 63.9% 5-year survival rates, respectively. Sixty-four stage I males and 65 stage I females had 84% and 90% 5-year survival rates, respectively. We saw no difference between those with or without lymph node dissection. Thirty-six stage II males and 25 stage II females had 66.7% and 60% 5-year survival rates, respectively. Of stage II patients, 23 had only one positive node, 22 had two to four positive nodes, and 9 had five or more positive nodes with 69%, 63%, and 55% 5-year survival rates, respectively. Large published series were used as historical controls [6,27,28], and significant differences were noted when compared to our stage II patients (P = 0.001)--those with two to four positive nodes (P = 0.03), and those with five or more positive nodes (P = 0.04). We conclude that there is a significant increase in survival for these stage II patients, at high risk of recurrence, receiving a tumor homogenate vaccine. This vaccine warrants further analysis, development, and use in a phase III randomized clinical trial.

Adult↗
PubMed1990

Measurement of airborne mite antigen in homes of asthmatic children.

The airborne concentration of major house dust mite antigen Der p1 was measured by low volume sampling (2 litres/min) in the homes of 68 allergic, asthmatic children. The presence of detectable airborne antigen was strongly associated with sensitivity to the mite, whereas there was no significant relation between sensitivity and the previously recommended threshold level of 2 micrograms Der p1 per g carpet dust. There was a significant association with lower threshold levels in carpet dust (0.5 microgram/g) but at no level was the association as strong as that with air measurements. Concentrations of airborne antigen were higher in rooms with wool carpets than in those with synthetic carpets or hard floors, but there was no significant difference between the dust levels of Der p1 in the two carpet types. Air sampling is a more appropriate method of assessing antigen exposure than dust sampling for asthmatic patients.

Adolescent↗
PubMed1990

Nonpharmacologic means of preventing asthma.

Cessation of smoking in the home is one of the most important nonpharmacologic actions to be recommended. There is a highly significant increase in wheezing, coughing, and respiratory infections in children with smoking mothers, and this increase is directly proportional to the number of cigarettes smoked. Cord blood IgE levels are increased in babies whose mothers smoke during pregnancy. Other agents, such as sulpur dioxide and chemical pollutants from industrial processes may play a role in the development or exacerbation, of asthma symptoms and should be avoided. One of the most interesting areas in food allergy is whether breast feeding causes sensitization or induces tolerance in infants to foods ingested by the mother. There is an increase in asthma in second-generation immigrant populations who are exposed, from birth, to the Western style of living which increases their exposure to house dust mite. Several studies have shown that month of birth is important in the development of specific allergies, for example, in the incidence of birch pollen allergy in Scandinavia. The presence of a pet in the home at birth is associated with a greater incidence of allergy to that animal. Our study in asthmatic children has shown a strong association (p less than 0.001) between the presence of allergens in the air in their homes (sampled retrospectively in the month of birth) with a positive skin test to those allergens.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants↗
PubMed1990

Allergy to mice. II. Further characterization of two major mouse allergens (AG 1 and AG 3) and immunohistochemical investigations of their sources.

Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and quantitative immunoelectrophoretic techniques have been used to characterize further the two major mouse allergens, antigen 1 (Ag 1) and antigen 3 (Ag 3). Gel filtration using Sephacryl S-200 showed Ag 1 to have a molecular weight of 18 kD and Ag 3 of 21 kD. SDS-PAGE followed by Western blotting onto nitrocellulose then incubation with individual antisera directed against each of the two major allergens, and an alkaline phosphatase enzyme system, was used to distinguish between the two allergens and indicated a molecular weight of 17 kD for Ag 1 and 16 kD for Ag 3. Ag 3 but not Ag 1 was shown to contain polysaccharide residues. Immunohistochemical staining of mouse skin sections demonstrated that antigens detected in whole dust extracts were present in the hair follicles, on the hair shafts and on the stratum corneum. Staining of similar sections using the rabbit anti-Ag 3 showed the presence of this major allergen in the hair follicles coating the hairs and extending along the skin surface. Serum from a pool of mouse-allergic subjects also demonstrated staining in the same areas when detected using a fluorescein-labelled anti-human IgE as second antibody. As both major allergens were present in extracts of fur this would appear to be most appropriate for use in diagnosis (i.e. skin test and RAST) and also possibly desensitization. However, dust from isolators (available in greater amounts) would be equally suitable.

Allergens↗
PubMed1990

School counselors' knowledge of eating disorders.

The purpose of this study was to examine school counselors' knowledge of adolescent eating disorders, specifically anorexia and bulimia nervosa. Participants were drawn from the national membership of the American Association of School Counselors; they were requested to complete a 43-item questionnaire on eating disorders. Of the 500 participants randomly selected, 337 (67%) returned usable questionnaires. There were 220 female and 117 male counselors; the mean age was 45.2 years. The majority held a master's degree and counseled high school students; the mean number of years they had been school counselors was 12.2. When asked how competent they were in helping students with eating disorders, 11% rated themselves as very competent, 49% believed they were moderately competent, and 40% believed they were not very competent. The majority (75%) did not believe it was their role to treat students with eating disorders; they were instead referred to an eating disorders program (40%), their parents (34%), or a psychiatrist or other physician (34%). The majority of counselors (72%) had encountered anorexic or bulimic students; the most common method of discovering students with a problem was by being informed by fellow students (35%). The majority of respondents were very knowledgeable regarding the signs and symptoms of anorexia and bulimia nervosa. Examination of their general knowledge of eating disorders revealed that they knew more about anorexia than bulimia. The two sources of eating disorders information utilized by at least half of the respondents were professional journals (70%) and workshops/professional conferences (56%).

Child↗
PubMed1989

IgG antibodies in relation to exposure to laboratory-animal allergens.

An ELISA technique has been used to measure levels of specific IgG in individuals exposed to laboratory animals in comparison to levels in unexposed individuals. The technique was to determine whether these levels could be useful as a monitor of exposure. Both symptomatic (with and without specific IgE) and nonsymptomatic individuals were studied. Several antigenic source materials were investigated for each animal. The IgG response was extremely complex and elicited a varied pattern of response between animals (mouse, rat, and rabbit). No evidence was found for raised IgG levels being directly related to the degree of exposure, more to the presence of clinical symptoms and specific IgE. Long-term heavy exposure to rats in nonsymptomatic individuals appeared to produce a suppression of the IgG response in relation to control levels. These findings suggest that IgG is not an indicator of exposure but demonstrate a varied response related to the presence of specific allergy to an animal, the particle size on which antigens are carried, and the physiologic state of the mucosa onto which the particles impact.

Allergens↗
PubMed1989

Inhalant allergy in asthmatic children: skin prick test, radioallergosorbent test and chemiluminescent assay compared with allergen levels in their mattress dusts.

Mattress dusts from the beds of 51 asthmatic children with positive skin tests to house dust mite were assayed for Der p I, Fel d I and certain viable fungi. The results of skin tests to grass, cat, dog, Alternaria, Aspergillus, Cladosporium and Penicillium, radioallergosorbent tests to cat, mite, dog and grass and the chemiluminescent assay were compared and correlations made with allergen concentrations in the dust. The sensitivity of the three tests appeared comparable (percentage agreement = 54.5-94), however, an increased level of allergen in the mattress dust was not a good indicator of the degree of sensitization of the child (p greater than 0.05).

Allergens↗
PubMed1988

Applications of a new optical technique for measuring the dielectrophoretic behaviour of micro-organisms.

It is shown that the dielectrophoretic behaviour (motion in non-uniform a.c. electric fields) of micro-organisms can conveniently and reproducibly be measured by monitoring the decrease in optical absorbance of a cell suspension as the cells are collected at a micro-electrode array. The dielectrophoretic behaviour, as a function of the frequency of the applied electric field and conductivity of the supporting solution, can be determined more quantitatively and rapidly than by methods so far described in the literature. Results are presented for Micrococcus lysodeikticus, Bacillus subtilis and Escherichia coli for the frequency range 20 Hz to 4 MHz and theoretical considerations are presented for the effect of solution conductivity. A value of 0.2 S/m has been derived for the effective conductivity of M. lysodeikticus.

Bacillus subtilis↗