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Biomedical subjects

S Melvin

Publications and source records attributed to S Melvin.

15 recordsLinked to original sources
PubMed2006

Assessment of permeable covers for odour reduction in piggery effluent ponds. 1. Laboratory-scale trials.

A variety of materials were trialed as supported permeable covers using a series of laboratory-scale anaerobic digesters. Efficacy of cover performance was assessed in terms of impact on odour and greenhouse gas emission rate, and the characteristics of anaerobic liquor. Data were collected over a 12-month period. Initially the covers reduced the rate of odour emission 40-100 times relative to uncovered digesters. After about three months, this decreased to about a threefold reduction in odour emission rate, which was maintained over the remainder of the trial. The covers did not alter methane emission rates. Carbon dioxide emission rates varied according to cover type. Performance of the covers was attributed to the physical characteristics of the cover materials and changes in liquor composition. The reductions in odour emission indicate that these covers offer a cost-effective method for odour control.

Air Pollution↗
PubMed2001

Laboratory investigation of supported permeable organic covers for the management of odour emissions from anaerobic piggery waste ponds.

Australian research has linked much of the odour arising from intensive livestock operations to pond treatment systems. A reduction in emissions from treatment ponds would therefore generally reduce odour emissions from intensive livestock operations. Published data indicates that the application of straw and other biological materials to effluent pond surfaces as a continuous cover reduces odour emissions. The effectiveness of these covers has not, however, been researched under controlled conditions. Using locally available materials, the efficacy of supported covers has been investigated using a series of laboratory anaerobic digesters treating typical piggery effluent. Research to date has focused on: identifying effective cover and cover support materials; quantifying odour reduction; identifying the impact use these covers may have on greenhouse gas emissions; devising practical and effective methods for constructing these covers. Results have confirmed that a variety of cover materials are effective in reducing pond odour emissions. Supporting the pond cover appears to extend the cover life expectancy. While greenhouse gas emissions appear to vary according to cover type, the overall significance of these emissions is not yet clear. The impact of permeable pond covers on overall pond performance requires additional research.

Agriculture↗
PubMed1986

Shedding of the common acute lymphoblastic leukemia antigen (CALLA) by lymphoblastoid cell lines.

The release of common acute lymphoblastic leukemia antigen (CALLA) into culture medium by lymphoblastoid cell lines was studied. CALLA release was detected using a solid phase indirect radioimmunometric assay which combines the specificity of lectins and monoclonal antibodies and using immunoadsorption of labeled CALLA in spent medium from cells incubated with 35S-methionine. No CALLA was present in the medium of cells pulse-labeled at 37 degrees C, when they were placed at 4 degrees C, thus this is an active process. Sequential analysis of soluble CALLA revealed shedding of CALLA to be associated with cell growth.

Antibodies, Monoclonal↗
PubMed1985

Genetic predisposition to acute lymphocytic leukemia in American blacks. A Pediatric Oncology Group study.

Recent reports have shown an association between genes lying within the major histocompatibility complex (MHC), particularly HLA and factor B (Bf), and acute lymphocytic leukemia (ALL) in white children. The frequencies of Bf and complement component C4 phenotypes in 90 black American children with ALL were examined to determine if a genetic association existed. The Bf and C4 results for the black children with ALL were compared with frequencies in healthy black Americans from the same geographic region. The BfF allele was carried by 95.6% of the black ALL patients compared with 86.1% of the controls (P = 0.017; relative risk = 3.5). In contrast, only 2.2% of the patients with ALL were homozygous for BfS compared with 9.8% of the controls (P = 0.043; relative risk = 0.2). These findings are similar to those observed in white American children. The C4A6 phenotype was found in 11.9% of the black children with ALL compared with 0.6% of the controls (P = 0.0026; relative risk = 22.7). These findings represent the first reported association of a particular allele whose gene lies within the MHC with ALL in black American children. The results suggest that the occurrence of ALL in black American children may be partially due to a genetic influence.

Adenosine Monophosphate↗
PubMed1985

The E rosette-associated antigen of T cells can be identified on blasts from patients with acute myeloblastic leukemia.

Monoclonal antibody T-11, considered specific for the sheep erythrocyte rosette-associated antigen of T cells, reacted with leukemic blasts from four of 23 patients with morphologic and cytochemical criteria for acute myeloblastic leukemia (AML). Although 83%, 87%, 88%, and 96% of the blasts from these patients reacted with T-11, only one patient demonstrated a small percentage of heat-stable E rosettes (5%). Antibody 9.6, which also reacts with the E rosette-associated antigen, was tested on blasts from two of the T-11-positive patients and was also strongly reactive (96% and 98%). Dual staining of blasts from these two patients demonstrated a small number of cells that simultaneously expressed the E rosette-associated antigen and myeloid-associated cytochemistries (myeloperoxidase [MPO] and Sudan black B). Additionally, leukemic blasts were identified that simultaneously expressed the E rosette-associated antigen and contained Auer rods. Antibody OKT-11 immunoprecipitated a 48,100-dalton glycoprotein from these leukemic blasts that is similar in molecular weight to that previously determined for the T cell surface protein (Tp50), thus providing strong evidence that this molecule can be found in some cases of AML. Because cells simultaneously expressing both the E rosette-associated antigen and MPO were identified, it would appear likely that leukemic blasts with only the E rosette-associated antigen or only MPO arose from the same progenitor. Our findings further demonstrate that the epitopes identified by antibodies OKT-11, T-11, and 9.6 are not always associated with, or sufficient for, 37 degrees C E rosette formation and can be found on blasts from patients with AML.

Antibodies, Monoclonal↗
PubMed1985

Rearrangement of immunoglobulin heavy chain genes in T cell acute lymphoblastic leukemia.

We studied the arrangement of the immunoglobulin heavy chain genes by Southern blot analysis of DNA freshly obtained from marrow blast cells of 14 children with T cell acute lymphoblastic leukemia (T-ALL) using probes to the C mu and JH gene segments: At least one of the C mu-gene alleles was rearranged in three cases. In two of these, one C mu gene had the germ-line configuration and one was rearranged, whereas both alleles were rearranged in the third case. In one case, a rearranged heavy chain gene hybridized to the C mu-region probe, but not to the JH probe, indicating that the entire JH region had been deleted. These results demonstrate that immunoglobulin heavy chain gene rearrangements are not restricted to B lineage lymphoproliferative diseases in humans.

Adolescent↗
PubMed1985

Acute mixed lineage leukemia: clinicopathologic correlations and prognostic significance.

The frequency and clinical significance of acute leukemia displaying both lymphoid and myeloid characteristics was determined in 123 consecutive children using a panel of lineage-associated markers. The leukemic blasts from 18 of 95 children (19%) with the diagnosis of acute lymphoblastic leukemia (ALL) by standard diagnostic criteria expressed myeloid-associated cell surface antigens. Despite immunological evidence of lymphoid differentiation (17 CALLA + and one T cell-associated antigen +) and findings of immunoglobulin gene rearrangement, blasts from these patients reacted with one to five monoclonal antibodies identifying myeloid-associated cell surface antigens (My-1, MCS.2, Mo1, SJ-D1, or 5F1). Dual staining with microsphere-conjugated antibodies and analysis by flow cytometry confirmed that some blasts were simultaneously expressing lymphoid- and myeloid-associated antigens. Conversely, blasts from seven of 28 patients (25%) with acute nonlymphocytic leukemia (ANLL), diagnosed by otherwise standard morphological and cytochemical criteria, expressed lymphoid-associated surface antigens. Dual staining of individual blasts demonstrated simultaneous expression of myeloperoxidase (MPO) (including Auer rods) in association with either T-11, CALLA, or terminal deoxynucleotidyl transferase. Blasts from one patient with ANLL demonstrated T cell receptor gene rearrangement, while blasts from another patient demonstrated characteristics associated with T (T-11), B (CALLA and heavy-chain immunoglobulin gene rearrangement), and myeloid (MPO) lineage. There were no consistent cytogenetic abnormalities, and no patient demonstrated independent leukemic clones. Each patient with typical ALL, except for myeloid-associated antigens, achieved complete remission with conventional induction therapy for ALL. By contrast, three of the seven children with ANLL whose blasts expressed the T-11 surface antigen failed ANLL induction therapy. These three patients subsequently achieved remission with ALL therapy.

Acute Disease↗
PubMed1984

Identification and characterization of a human thymus-leukemia antigen (43-kDa/513TL) bearing a structural relationship to HLA.

A human thymus-leukemia-like antigen has been identified that is antigenically distinct from T6/HTA-1. This was accomplished with a rabbit antiserum (513) which was prepared against lymphoblasts that were E rosette negative (E-), human thymus antigen positive (HuTA+), cALLA-, DR-, SmIg- from a patient who presented with a mediastinal mass and a WBC count of 130 X 10(9) cells/1. Following absorption with B cell and "null" cell lines, 513 exhibited prominent reactivity with a membrane antigen that was present on normal thymocytes and lymphoblasts from 11 of 13 patients with T cell ALL and 1 of 16 patients with common ALL, but was not detected on normal peripheral blood lymphocytes, normal bone marrow cells and leukemic lymphoblasts with an undifferentiated phenotype. SDS-PAGE analysis of this antigen indicated that it was composed of two subunits, 43-kDa and 12-kDa. Sequential absorption experiments revealed that: (1) the 12-kDa subunit was antigenically similar to beta 2 microglobulin; (2) the intact molecule did not exhibit HLA-A, B or C "framework" determinants; (3) the molecule was antigenically distinct from a human thymus-leukemia antigen HTA-1 (recognized by monoclonal antibodies NA1/34 and OKT6); and (4) the molecule was antigenically distinct from adenosine deaminase. It is concluded that 513 reacts with a membrane protein (designated 513TL) which exhibits properties characteristic of a histocompatibility-like antigen whose expression is restricted to thymocytes and some leukemias (TL antigen). Its antigenic distinction from another recently characterized human TL antigen, HTA-1, suggests polymorphism among this family of alloantigens.

Adenosine Deaminase↗
PubMed1984

Acute leukaemia with mixed lymphoid and myeloid phenotype.

Three children with acute leukaemia had blasts that expressed both lymphoid and myeloid markers. The blasts met immunological criteria for acute lymphoblastic leukaemia (ALL)--common ALL antigen+, HLA-DR+, terminal deoxynucleotidyl transferase+--but their cytochemical features, including positive myeloperoxidase and Sudan black B, were those of acute nonlymphoblastic leukaemia (ANLL) as defined by the French-American-British Group. 30% of the blasts from one of two patients tested reacted with a monoclonal antibody specific for nonlymphoid cells (MCS-2). The wide overlap in the percentages of blasts expressing lymphoid or myeloid markers indicates that some leukaemic cells in each child had a mixed phenotype. There were no consistent cytogenetic findings, and the Philadelphia chromosome was not present. Complete remission was induced by treatment effective for either ALL (two patients) or ANLL. These three cases appear to represent a rare leukaemia subtype that we have designated acute leukaemia with mixed lymphoid and myeloid phenotype. Its recognition may be important in treatment, since two patients achieved remission with standard therapy for ALL. These cases demonstrate further the phenotypic heterogeneity that may be seen in leukaemic cell differentiation.

Acute Disease↗
PubMed1984

Sudan black B positive acute lymphoblastic leukaemia.

The presence of greater than 3% Sudan black B (SBB) positivity in leukaemic blasts has been considered diagnostic of acute non-lymphocytic leukaemia (ANLL). A rare report has indicated that this finding may not be specific for ANLL. In order to determine whether SBB could be found in acute lymphoblastic leukaemia (ALL) the data on 350 patients with newly diagnosed ALL were reviewed. Six patients (1.6%) were found to have 5% or greater SBB positive blasts. The diagnosis of ALL was supported by morphology, cytochemistries, immunologic markers, therapeutic response, and in one case immunoglobulin gene rearrangement. It is important to recognize the fact that SBB is not specific for AML and may be found in the blasts of patients with ALL.

Adolescent↗
PubMed1984

Lineage switch in acute leukemia.

Conversions of leukemic cell lineage (lymphoid or myeloid) have been reported only rarely. Our review of the cytochemical and immunophenotypic features of 89 cases of childhood leukemia in marrow relapse indicated lineage switch (lymphoid to myeloid or the reverse) in six patients (6.7%). Five patients with acute lymphoblastic leukemia (ALL) at diagnosis had converted to acute nonlymphoblastic leukemia (ANLL), and one had converted from ANLL to ALL. Each child received lineage-specific multiagent chemotherapy when initially diagnosed, and all achieved a complete remission. After conversion, four patients readily achieved second remissions with treatment for the phenotype evident at lineage switch. Two patients with ANLL at conversion failed ALL-directed reinduction, while one of the two responded to high-dose cytarabine but died during bone marrow hypoplasia, emphasizing the importance of prompt recognition of lineage switch and selection of an appropriate plan of retreatment. Cytogenetic studies disclosed evidence of clonal selection in one patient and clonal stability in two. These findings indicate an unexpectedly high frequency of lineage switch in patients who relapse in the bone marrow after intensive chemotherapy. Although specific causative factors could not be identified, our observations suggest at least two general mechanisms for lineage switch in acute leukemia. In one, chemotherapy appears to eradicate the dominant clone present at diagnosis, permitting expansion of a secondary clone with a different phenotype. In the second, drug-induced changes in the original clone may either amplify or suppress differentiation programs so that phenotypic shift is possible.

Acute Disease↗
PubMed1983

Granular acute lymphoblastic leukemia.

Granules in blasts are most typical of acute myeloblastic leukemia. However, there have been scattered reports of patients with acute lymphoblastic leukemia (ALL) that have lymphoblasts with azurophilic cytoplasmic granules. These reports do not describe immunologic markers or cytogenetics. We report five additional cases with detailed cytologic, immunologic, and cytogenetic studies. At diagnosis one of these patients had central nervous system disease, while the others had no unusual features. Four of the five patients attained remission. The blasts of all five patients contained distinct cytoplasmic azurophilic granules. The granules were negative for peroxidase and chloroacetate esterase and positive for PAS, acid phosphatase, alpha-naphthyl acetate esterase incompletely fluoride inhibited, alpha-naphthyl butyrate esterase, and in one case, Sudan black B. In the one patient studied by electron microscopy, characteristic lymphoblasts contained membrane-bound electron lucent inclusions, which stained positively with non-specific esterase. Immunologic markers showed a common ALL phenotype. Different cytogenetic abnormalities were seen in all cases. It is important to recognize the characteristics of this morphologic subtype of ALL in order to avoid a misdiagnosis of acute nonlymphocytic leukemia.

Adolescent↗
PubMed1982

Non-T, non-B lymphomas are rare in childhood and associated with cutaneous tumor.

Tumor cells from a total of 116 children with non-Hodgkin's lymphoma were studied for their pattern of reactivity with a battery of cell markers, including their capacity for spontaneous formation of sheep erythrocyte rosettes (E-rosettes), demonstration of surface immunoglobulins (SIg), and positivity with antisera against T-cell antigens, the common acute-lymphoblastic-leukemia-associated antigen (cALLa), and Ia-like antigens. Fifty-eight children (50%) had T-cell lymphomas, including all those with mediastinal tumors. Fifty children (43%) had B-cell lymphomas, including 44 of the 45 with abdominal primaries. Eight children (7%) had non-T, non-B tumors, 4 of whom presented at a young age with cutaneous lymphoblastic tumors. These results demonstrate that the great majority of children with NHL, not leukemic at diagnosis, have tumors clearly committed to either T- or B-cell differentiation pathways and only rarely exhibit the common ALL phenotype (cALLa+, Ia+, E-, T-, SIg-), contrasting with the distribution of childhood lymphoblastic leukemias. The unusual association of these non-T, non-B cases with skin involvement has not previously been reported, raising speculation regarding patterns of lymphocyte traffic and origins of childhood lymphomas and leukemias.

Adolescent↗