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R A McBride

Publications and source records attributed to R A McBride.

At least 19 recordsLinked to original sources
PubMed2004

Assessing the use of poplar tree systems as a landfill evapotranspiration barrier with the SHAW model.

The use of poplar tree systems (PTS) as evapotranspiration barriers on decommissioned landfills is gaining attention as an option for leachate management. This study involved field-testing the Simultaneous Heat and Water (SHAW) model for its ability to reliably estimate poplar transpiration, volumetric soil water content, and soil temperature at a landfill located in southern Ontario, Canada. The model was then used to estimate deep drainage and to ascertain the influence of a young PTS on the soil water balance of the landfill cover. The SHAW model tended to underestimate poplar transpiration [mean difference (MD) ranged from 0.33 to 3.55 mm on a daily total basis] and overestimate volumetric soil water content by up to 0.10 m3 m(-3). The model estimated soil temperature very well, particularly in the upper 1 m of the landfill cover (MD ranged from -0.1 to 1.6 x degrees C in this layer). The SHAW model simulations showed that deep drainage decreased appreciably with the presence of a young PTS largely through increased interception of rainfall, and that PTS have a good potential to act as effective evapotranspiration barriers in northern temperate climate zones.

Biodegradation, Environmental↗
PubMed2004

Laboratory-scale measurements of N2O and CH4 emissions from hybrid poplars (Populus deltoides x Populus nigra).

The purpose of this study was to determine whether or not young hybrid poplar (Populus deltoides x Populus nigra) could transport landfill biogas internally from the root zone to the atmosphere, thereby acting as conduits for landfill gas release. Fluxes of methane (CH4) and nitrous oxide (N2O) from the seedlings to the atmosphere were measured under controlled conditions using dynamic flux chambers and a tunable diode laser trace gas analyser (TDLTGA). Nitrous oxide was emitted from the seedlings, but only when extremely high soil N2O concentrations were applied to the root zone. In contrast, no detectable emissions of CH4 were measured in a similar experimental trial. Visible plant morphological responses, characteristic of flood-tolerant trees attempting to cope with the negative effects of soil hypoxia, were observed during the CH4 experiments. Leaf chlorosis, leaf abscission and adventitious roots were all visible plant responses. In addition, seedling survival was observed to be highest in the biogas 'hot spot' areas of a local municipal solid waste landfill involved in this study. Based on the available literature, these observations suggest that CH4 can be transported internally by Populus deltoides x Populus nigra seedlings in trace amounts, although future research is required to fully test this hypothesis.

Air Pollutants↗
PubMed1996

Calcofluor white stain for the detection of Pneumocystis carinii in transbronchial lung biopsy specimens: a study of 68 cases.

Calcofluor white (CFW), a chemofluorescent agent, has proven effective in the recognition of Pneumocystis carinii cysts in respiratory fluids and secretions. However, its usefulness in the recognition of P. carinii cysts in tissue preparations has not been established. We studied 68 formalin-fixed, paraffin-embedded, transbronchial tissue biopsy specimens from individuals seropositive for the human immunodeficiency virus and stained them with the CFW stain and the conventional Gomori methenamine silver (GMS) stain to determine the concordance rate of the two stains. CFW-positive specimens showed light peripheral staining and a unique double parenthesis-like structure near the center of the cysts. Thirty-six (52.9%) of the 68 specimens were CFW and GMS positive, whereas 27 (39.7%) of the specimens were negative by both techniques, yielding a concordance rate of 92.6%. Five (7.4%) of the 68 specimens showed disparate results, and, of these, four (5.9%) were CFW positive and GMS negative, whereas one (1.5%) was CFW negative and GMS positive. We conclude that the CFW stain is suitable and useful for the demonstration of P. carinii cysts in tissue preparations.

AIDS-Related Opportunistic Infections↗
PubMed1995

Modification of the fungi-fluor and the genetic systems fluorescent antibody methods for detection of Pneumocystis carinii in bronchoalveolar lavage specimens.

Four hundred forty-five bronchoalveolar lavage specimens from patients with the human immunodeficiency virus were preserved in Saccomano's fixative and stained for Pneumocystis carinii cysts by a modified method with Fungi-Fluor Solution A (Polysciences, Warrington, Pa) and the Genetic Systems Pneumocystis carinii Immunofluorescence Antibody (Genetic Systems Corp, Seattle, Wash). The majority of patients had been treated for suspected P carinii pneumonia for a few days prior to collection of bronchoalveolar lavage specimens. P carinii cysts were detected in 194 (43.6%) specimens. Both stains identified P carinii in 166 (37.3%) specimens and were negative in 251 (56.4%), yielding a concordance rate of 93.7%. P carinii cysts were detected in 25 (5.6%) specimens by the Genetic Systems stain only, and in 3 (0.7%) specimens by the Fungi-Fluor stain only. The sensitivity for detecting cysts of P carinii was significantly greater with the Genetic Systems stain (P < .01).

Bronchoalveolar Lavage Fluid↗
PubMed1992

False aneuploidy in benign tumors with a high lymphocyte content: a study of Warthin's tumor and benign thymoma.

The quality of results of flow cytometric DNA content analysis of formalin-fixed, paraffin-embedded tissue may be affected by a number of preanalytical variables. We performed flow cytometric DNA content analysis on two types of benign tumors to investigate the effect of a prominent lymphocytic component: Warthin's tumor (N = 20) and benign thymoma (N = 8). Malignant tumors (N = 23) were included as DNA aneuploid controls. All tissues studied were archival material processed using Hedley's technique either without prolonged rehydration in water (day 0 samples) or with 24- or 48-hour rehydration (day 1 and day 2 samples, respectively). Image cytometric DNA ploidy analysis was also performed on most cases. Eight cases (40%) of Warthin's tumor and five cases (63%) of benign thymoma showed either hyperdiploid peaks or marked asymmetry on the day 0 DNA histograms; nine of the malignant tumors were aneuploid. The DNA histogram abnormalities of the benign tumors could be gated out by excluding the lymphocyte nuclei. None of the DNA indices of the benign tumors corresponded with expected deviations based on published chromosomal studies. All of the DNA histogram abnormalities of the benign tumors disappeared and/or fused with the main peaks on the day 1 or day 2 samples, except for one case of benign thymoma. All the DNA aneuploid peaks on the malignant tumors persisted with prolonged rehydration. Image cytometric DNA analysis showed a diploid pattern in all benign tumors. We conclude that a high lymphocyte content may be a cause of false aneuploidy in these benign tumors. Furthermore, the degree of rehydration appears to be an important factor in achieving optimum fluorochrome staining of DNA.

Adenolymphoma↗
PubMed1989

Effect of landfill leachate irrigation on red maple (Acer rubrum L.) and sugar maple (Acer saccharum Marsh.) seedling growth and on foliar nutrient concentrations.

Greenhouse experiments were conducted to investigate the nature and severity of stresses imposed on northern hardwood tree species (red maple (Acer rubrum L.) and sugar maple (Acer saccharum Marsh.)) by the application of municipal landfill leachate. Red maple seedlings received applications of untreated and pretreated (lime, activated carbon) leachate, to both leaves and soil, at irrigation rates consistent with evapotranspirational demands. Plant height measurements indicated no significant growth effects arising from leachate application over a 7-week period. Stem diameter, however, was positively affected by applications of both untreated and lime-treated leachate diluted to 75% with deionized water. Iron foliar concentrations were significantly higher in seedlings irrigated with untreated leachate applied to leaves and soil, but not in seedlings where leachate was applied to soil only. Nitrogen foliar concentrations were substantially higher in seedlings receiving undiluted and untreated leachate applied to the soil only. The Cu concentration of the red maple foliage decreased appreciably in plants receiving moderate applications of leachate. Foliar Ca concentrations decreased notably in seedlings irrigated with untreated leachate applied to the soil and with diluted, carbon-treated leachate. The Cu concentration of the red maple foliage decreased appreciably in plants receiving applications of undiluted and 50% water-diluted lime-treated leachate while Mn levels were consistently high across all treatments. Leachate application did not cause any discernable changes in foliar concentrations of P, K, Mg, B or Zn. In an ancillary experiment, sugar maple seedlings were subjected to saturation/ drainage treatment cycles with undiluted and untreated leachate. Severe visible symptoms of vegetative stress were apparent within 24 h and 100% seedling mortality occurred after five such waterlogging cycles. Fe assimilation was apparent in both leachate treatments relative to the 24 h water treatment. Despite the short-term nature of the experiments, the results indicate how quickly forest vegetation may respond to altered chemical environments. This underscores the need for correct installation and control of leachate irrigation systems.

Journal Article↗
PubMed1988

Temporal bone pathology of metastatic T-cell lymphoma.

Metastatic lymphoma involving the temporal bone is a rare tumour. A review of the English literature revealed only 13 reported cases. The common metastatic sites within the temporal bone are bone marrow and the internal auditory canal (IAC). Non-Hodgkin lymphoma has a tendency to infiltrate to the inner ear and middle ear, with bone marrow involvement. Recent advances in immunology have redefined the malignant lymphoma as a neoplasm of the immune system that has involved T and B cells. We present a case of non-Hodgkin T-cell lymphoma that metastasized to the temporal bone and central nervous system.

Humans↗
PubMed1988

Quadricuspid aortic valve and single coronary ostium.

We describe an autopsy patient in whom a rare congenital anomaly of quadricuspid semilunar aortic valve and coronary arteries originating from a single orifice of one aortic sinus occurred. To the best of our knowledge, this combination of cardiac anomalies has not been reported.

Aortic Valve↗
PubMed1986

Metastatic seminoma of the temporal bone.

Temporal bone metastasis of classic testicular seminoma is extremely rare in the English literature. Except for a clinical case report of seminoma in the temporal bone, to our knowledge there is no temporal bone pathology report of secondary seminoma. In the left temporal bone of the present case, tumor cell infiltration was found in the external auditory canal, tympanic membrane, middle ear cavity, tympanic and mastoid mucosa, tensor tympani muscle, and so on.

Adult↗
PubMed1984

Individual ev loci determine characteristic patterns of endogenous retroviral envelope antigen expression during lymphocyte maturation.

A comparative study of the expression of retroviral envelope antigen by T and B lymphocytes at different maturational stages was made with chickens typed for genomic ev loci. All lymphocyte subclasses from chf(-) chickens were negative for expression of retroviral envelope antigen. By contrast, cells of the lymphocyte lineage from all the chf(+) lines examined were positive for expression, with the levels of envelope antigen in the lymphoblasts exceeding the levels in the immature and resting cells. This pattern of lymphocyte expression was found in lines of chickens in which the expression of chf in fibroblasts was encoded by the ev 3, ev 6, or ev 9 loci. Plasma cells from those chf(+) lines possessing ev 6 expressed higher levels of envelope antigen than the lymphoblasts, an effect not observed with the chf(+) lines lacking ev 6.

Animals↗
PubMed1981

MHC gene control of growth of avian sarcoma virus-induced tumours in chickens: a study on the role of virus strains.

A comparison was made of growth patterns (progression/regression) of tumours induced by different strains of avian sarcoma virus in two partially congenic inbred lines of chickens homozygous for different MHC haplotypes. In each instance studied, the ability to regress tumours was shown to be a dominant trait controlled by MHC-linked genes. The results also demonstrate a difference in growth pattern between tumours induced by different strains of virus in an inbred line as well as different growth patterns of tumours induced by the same strain of virus in the two inbred lines. We conclude that the MNC-linked resistance gene is part of a polymorphic genetic region and, in addition, that there is immunogenic heterogeneity of the viral gene product expressed on tumour cells induced by closely related viral strains which is relevant to tumour regression. We suggest that the product of the src gene, p60src, is a plausible candidate for the immunogenic target of the MHC-linked rejection response.

Animals↗
PubMed1981

Complementing MHC- and non-MHC-linked genes and resistance to avian sarcoma virus-induced tumours in inbred lines of chickens.

Schmidt-Ruppin Rous sarcoma virus, subgroup B (SR-RSV-B), was inoculated into the wingwebs of chickens from three partially congenic inbred lines, G-B1, G-B2 and G-B3, homozygous for different MHC (B region) haplotypes (genotypes = B1/B1, B2/B2 and B3/B3 respectively). All birds developed tumours but only the G-B2 line resisted progressive tumour growth. Birds from lines G-B1 and G-B3 approached 100% susceptibility to progressive tumour growth, whereas most (G-B1 X G-B3) F1 hybrids were resistant to tumours induced by SR-RSV-B. The association of the resistance trait in F1 hybrids with genes of the B region was investigated by testing progeny of (G-B1 X G-B3) X B-B1 F1 and (G-B1 X G-B2) X G-B3 F1 backcross matings. Approximately 27% of the backcross population was resistant to SR-RSV-B-induced tumours and these resistant offspring were predominantly of the B1/B3 phenotype. We interpret these results to mean that resistance to progressive tumour growth involves complementation between genes (allelic or at separate loci) linked to or within the B region and that resistance is effective only when the complementing B region genes act in concert with complementing genes which assort independently of the MHC. We suggest that complementing B region-linked genes are homologues of complementing murine H-2-linked Ir genes. The function of the B region in determining growth of sarcomas may therefore be analogous to that of Ir genes.

Alleles↗
PubMed1981

Heterologous tumor growth patterns induced in related MHC-defined chicken lines by separate isolates of an avian sarcoma virus strain.

Different patterns of tumour growth resulted from inoculation of separate isolates of the Subgroup C Bratislava 77 strain (B77) of Avian Sarcoma Virus (ASV) into three closely-related inbred lines of chickens. The major genetic difference between these chicken lines is that each is homozygous for a different MHC haplotype. Since for one of the viral isolates, resistance to progressive tumour growth has been shown to be controlled by MHC-linked genes, the data presented here suggest that MHC-controlled tumour rejection operates on viral or cellular determinants different from those which define classical viral group of subgroup specificity.

Alpharetrovirus↗
PubMed1978

Role of B cells in the expression of genetic resistance to growth of Rous sarcoma in the chicken.

Resistance to the development of progressively growing tumors induced by Rous sarcoma virus is a dominant trait controlled by a gene linked to the major histocompatibility complex (MHC). The effect of bursectomy (Bx) on the expression of this trait was studied in two inbred lines of chickens homozygous for different MHC alleles, and which differ with respect to the gene controlling resistance to Rous tumors. The results show that Bx alters the expression of the trait, since genetically resistant birds were rendered highly susceptible to progressive tumor growth. The bursa of Fabricius thus makes an important contribution to resistance. The results do not indicate whether genetic resistance is mediated exclusively by B cells or by another bursa-dependent population.

Animals↗
PubMed1977

Rous sarcomas in chickens: enhanced growth coexisting with concomitant immunity.

Chickens bearing Rous sarcoma virus-induced tumors in one wing did not develop new tumors when subsequently inoculated with Rous sarcoma virus in the other wing. However, the second inoculation of Rous sarcoma virus caused accelerated growth of the established tumors. This phenomenon was found to be bursa-dependent. Paradoxically, established tumors in bursectomized chickens grew at a diminished rate if the chickens were reinoculated with Rous sarcoma virus.

Animals↗