Biomedical subjects

Matthew Wand

Publications and source records attributed to Matthew Wand.

6 recordsLinked to original sources

PubMed2004

Detection of airborne rhinovirus and its relation to outdoor air supply in office environments.

Rhinoviruses are major causes of morbidity in patients with respiratory diseases; however, their modes of transmission are controversial. We investigated detection of airborne rhinovirus in office environments by polymerase chain reaction technology and related detection to outdoor air supply rates. We sampled air from 9 A.M. to 5 P.M. each workday, with each sample run for 1 work week. We directly extracted RNA from the filters for nested reverse transcriptase-polymerase chain reaction analysis of rhinovirus. Nasal lavage samples from building occupants with upper respiratory infections were also collected. Indoor carbon dioxide (CO2 concentrations were recorded every 10 minutes as a surrogate for outdoor air supply. To increase the range of CO2 concentrations, we adjusted the outdoor air supply rates every 3 months. Generalized additive models demonstrated an association between the probability of detecting airborne rhinovirus and a weekly average CO2 concentration greater than approximately 100 ppm, after controlling for covariates. In addition, one rhinovirus from a nasal lavage contained an identical nucleic acid sequence similar to that in the building air collected during the same week. These results suggest that occupants in buildings with low outdoor air supply may have an increased risk of exposure to infectious droplet nuclei emanating from a fellow building occupant.

Air Microbiology↗

PubMed2004

Chronic caregiver stress and IgE expression, allergen-induced proliferation, and cytokine profiles in a birth cohort predisposed to atopy.

BACKGROUND: Psychologic stress modifies immune function and cytokine production. OBJECTIVE: We examined relationships between caregiver stress on the following markers of early childhood immune response: (1) IgE expression (n=215); (2) mitogen-induced and allergen-specific (Dermatophagoides farinae [Der f 1] and cockroach [Bla g 2]) proliferative response (n=114); and (3) subsequent cytokine expression (INF-gamma, TNF-alpha, IL-10, and IL-13) in a prospective birth cohort predisposed to atopy. METHODS: Caregiver stress was measured at 2-month intervals for the first 2 years of life and yearly thereafter by using the Perceived Stress Scale. A subsequent blood sample obtained from the children (median age, 2.1 years; range, 18-32 months) was analyzed for total serum IgE level and allergen-induced proliferation quantified as the stimulation index (SI; mean thymidine incorporation of the stimulated sample divided by that of the unstimulated sample). The relationship between stress and the proliferative response (SI >3 vs SI < or =3), and total IgE level (< or =100 IU/mL vs >100 IU/mL) was examined by using logistic regression. The relationship between cytokine levels and stress was analyzed by using linear regression. RESULTS: In adjusted analyses higher caregiver stress in the first 6 months after birth was associated with a Der f 1 SI of greater than 3 (odds ratio [OR], 1.5; 95% CI, 1.0-2.3) and nominally associated with a Bla g 2 SI of greater than 3 (OR, 1.13; 95% CI, 0.7-1.8). Higher stress between ages 6 and 18 months was associated with a high total IgE level (OR, 2.03; 95% CI, 1.1-3.6). Higher stress was significantly associated with increased production of TNF-alpha, with a suggested trend between higher stress and reduced INF-gamma production. CONCLUSION: Increased stress in early childhood was associated with an atopic immune profile in these children predisposed to atopy-asthma.

Allergens↗

PubMed2002

The urban spread of visceral leishmaniasis: clues from spatial analysis.

BACKGROUND: The pattern of spread of visceral leishmaniasis in Brazilian cities is poorly understood. METHODS: We used geographic information systems and spatial statistics to evaluate the distribution of 1061 cases of visceral leishmaniasis in Teresina, Brazil, in 1993 through 1996. RESULTS: A locally weighted (LOESS) regression model, which was fit as a smoothed function of spatial coordinates, demonstrated large-scale variation, with high incidence rates in peripheral neighborhoods that bordered forest land and pastures. Moran's I indicated small-scale variation and clustering up to 300 m, roughly the flight range of the sand fly vector. CONCLUSIONS: Spatial analytical techniques can identify high-risk areas for targeting control interventions.

Brazil↗

PubMed2002

Activation of the transcription factor NF-kappaB by Campylobacter jejuni.

Campylobacter jejuni is a food-borne pathogen responsible for infectious enterocolitis. The early-response transcription factor NF-kappa B triggers the expression of genes associated with cellular immune and inflammatory responses. Co-incubation of HeLa cells with viable C. jejuni leads to the activation of the transcription factor NF-kappa B as determined by specific induction of a cellular luciferase-based reporter. Boiled cell-free extracts of C. jejuni are also potent dose-dependent stimulators of NF-kappa B-dependent transcription, the levels of which can reach up to 1000-fold as compared with independent controls. Using both cultured HeLa cells and human colonic epithelial (HCA-7) cells, the activation of NF-kappa B by C. jejuni boiled extract has been monitored through the degradation of IKB alpha and DNA binding of the nuclear translocated p50/p65 heterodimer of NF-kappa B. These events are co-ordinated with elaboration of the pro-inflammatory cytokine interleukin-8. Fractionation of the boiled C. jejuni extract suggests that the majority of the bioactive component has a molecular mass of 3 kDa or less, which is insensitive to proteinase K treatment.

Blotting, Western↗

PubMed2002

Using a neural network with flow cytometry histograms to recognize cell surface protein binding patterns.

Flow cytometric systems are being used increasingly in all branches of biological science including medicine. To develop analytic tools for identifying unknown molecules such as the antibodies that recognize different structure in the identical antigens, we explored use of a neural network in flow cytometry data comparison. Peak locations were extracted from flow cytometry histograms and we used the Marquardt backpropagation neural networks to recognize identical or similar binding patterns between antibodies and antigens based on the peak locations. The neural network showed 93.8% to 99.6% correct classification rates for identical or similar molecules. This suggests that the neural network technique can be useful in flow cytometry histogram data analysis.

Antibodies, Monoclonal↗

PubMed2002

Matching of flow-cytometry histograms using information theory in feature space.

Flow cytometry is a widely available technique for analyzing cell-surface protein expression. Data obtained from flow cytometry is frequently used to produce fluorescence intensity histograms. Comparison of histograms can be useful in the identification of unknown molecules and in the analysis of protein expression. In this study, we examined the combination of a new smoothing technique called SiZer with information theory to measure the difference between cytometry histograms. SiZer provides cross-bandwidth smoothing and allowed analysis in feature space. The new methods were tested on a panel of monoclonal antibodies raised against proteins expressed on peripheral blood lymphocytes and compared with previous methods. The findings suggest that comparing information content of histograms in feature space is effective and efficient for identifying antibodies with similar cell-surface binding patterns.

Animals↗