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Biomedical subjects

M E Reid

Publications and source records attributed to M E Reid.

At least 37 records · Page 2Linked to original sources
PubMed2003

A novel DI*A allele without the Band 3-Memphis mutation in Amazonian Indians.

BACKGROUND AND OBJECTIVES: The blood-group antigens Dia and Dib are carried on erythrocyte band 3 and are defined by a single amino acid substitution at position 854 (Leu for Dia and Pro for Dib). The Band 3-Memphis variant has a point mutation (166A>G) in the SLC4A1 gene, which encodes the amino acid substitution Lys56Glu. Two types of Band 3-Memphis, variants I and II, are distinguished by their susceptibility to covalent labelling with 4,4'-diisothiocyanato-1,2-diphenylethane-2,2'-disulphonic acid (H2DIDS). Memphis II is more readily labelled than Memphis I or normal band 3. It is reported that Memphis II is associated with Dia. In a study designed to determine the frequency of the DI*A/DI*B and 166A>G polymorphisms in different populations in Brazil, we found a new DI*A allele. MATERIALS AND METHODS: We studied DNA samples from 70 Amazonian Indians, 71 individuals of Japanese descent, 93 random Brazilian blood donors and 84 blacks with sickle cell disease. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analyses were performed on all samples, using MspI for DI*A/DI*B (exon 19) and MnlI for 166A>G (exon 4). Exon 4 and exon 19 from four outliers were sequenced. RESULTS: Among Amazonian Indians, DI*A and 166G mutations both had a high frequency (0.57 and 0.54, respectively). In individuals of Japanese descent, these alleles were moderately frequent (0.07 and 0.19, respectively). We identified a new allele with DI*A and 166A (56Lys) in four Amazonian Indians. CONCLUSIONS: Our results revealed that DI*A does not have a strict association with 166G. They also show the relevance of testing a cohort of different populations.

Alleles↗
PubMed2003

Selenium supplementation, baseline plasma selenium status and incidence of prostate cancer: an analysis of the complete treatment period of the Nutritional Prevention of Cancer Trial.

OBJECTIVE: To present the results (to January 1996, the end of blinded treatment) of the Nutritional Prevention of Cancer (NPC) Trial, a randomized trial of selenium (200 micro g daily) designed to test the hypothesis that selenium supplementation (SS) could reduce the risk of recurrent nonmelanoma skin cancer among 1312 residents of the Eastern USA. MATERIALS AND METHODS: Original secondary analyses of the NPC to 1993 showed striking inverse associations between SS and prostate cancer incidence. A subsequent report revealed that this effect was accentuated among men with the lowest baseline plasma selenium concentrations. The effects of treatment overall and within subgroups of baseline prostate-specific antigen (PSA) and plasma selenium concentrations were examined using incidence rate ratios and Cox proportional hazards models. RESULTS: SS continued to significantly reduce the overall incidence (relative risk and 95% confidence interval) of prostate cancer (0.51, 0.29-0.87). The protective effect of SS appeared to be confined to those with a baseline PSA level of <or= 4 ng/mL (0.35, 0.13-0.87), although the interaction of baseline PSA and treatment was not statistically significant. Participants with baseline plasma selenium concentrations only in the lowest two tertiles (< 123.2 ng/mL) had significant reductions in prostate cancer incidence. A significant interaction between baseline plasma selenium and treatment was detected. CONCLUSION: To the end of the blinded treatment the NPC trial continued to show a significant protective effect of SS on the overall incidence of prostate cancer, although the effect was restricted to those with lower baseline PSA and plasma selenium concentrations.

Biopsy↗
PubMed2003

Production of recombinant murine-human chimeric IgM and IgG anti-Js(b) for use in the clinical laboratory.

BACKGROUND: Directly agglutinating MoAbs are more useful than IgG MoAbs of murine origin for typing RBCs from donors and patients. The molecular manipulation and conversion of a murine IgG MoAb into mouse- human chimeric IgM and IgG antibodies are described. STUDY DESIGN AND METHODS: cDNA encoding the variable heavy- and light-chain genes of a murine hybridoma anti-Jsb cell line (MIMA-8) were cloned into human IgM or IgG expression vectors, which were then separately stably transfected into SP2/0-Ag14 B-cells. The secreted antibodies were screened by ELISA and analyzed by flow cytometry and hemagglutination. RESULTS: Forty percent (16 of 40) of the stable clones secreted IgM and 66 percent (12 of 18) of the stable clones secreted IgG. The chimeric IgM from the highest expressing clone reacted 4+ in LISS at room temperature. The chimeric IgG from one clone reacted 4+ by the IAT, resembling the specificity of the original murine antibody. Both manipulated MoAbs reacted specifically with RBCs as assessed by flow cytometry. CONCLUSION: Human-mouse chimeric IgM and IgG from a murine IgG MoAb anti-Jsb has been successfully engineered for use in the clinical laboratory. This approach can potentially be used to manipulate other murine MoAbs to blood group antigens into more clinically useful human isotypes.

Animals↗
PubMed2003

Selenium and prevention of prostate cancer in high-risk men: the Negative Biopsy Study.

Epidemiological and clinical studies suggesting a significant inverse relationship between intake of dietary selenium and overall cancer risk have led to initiation of a randomized, placebo-controlled, phase III clinical trial testing the safety and efficacy of selenized yeast as a chemopreventive agent for prostate cancer. Participants eligible for the 'Negative Biopsy Study', which was initiated in August 1999, are men considered to be at high risk for prostate cancer because of at least one negative sextant prostate biopsy, which was clinically indicated within 1 year of enrollment to the study. After a 30-day run-in period to ensure protocol compliance, participants are randomized to receive either 200 or 400 microg selenized yeast or matched placebo once daily. Primary study endpoints include development of prostate cancer and prostate-specific antigen (PSA) velocity. Secondary biochemical endpoints include change in chromagranin A and alkaline phosphatase. As of 1 June 2003, 514 eligible participants had been enrolled. Randomization schema was effective for selected parameters including age, body mass index, smoking status, baseline PSA and baseline plasma selenium level. Various data, including medical history, family history, and urological symptoms and specimens (including blood and subsequent prostate biopsy samples) had been collected at baseline, and throughout both the intervention and follow-up stages of the protocol. The goal for accrual is 700 evaluable participants.

Aged↗
PubMed2003

Selenium and inhibition of disease progression in men diagnosed with prostate carcinoma: study design and baseline characteristics of the 'Watchful Waiting' Study.

Impediment of the promotion and progression stages of carcinogenesis of the prostate could have a profound impact on treatment choice and prognosis for prostate cancer. Efficacious chemopreventive agents that elicit their activity by slowing the processes of progression could make watchful waiting a viable alternative for a large population of men or could delay the necessity for surgery, radiation or other more invasive treatment modalities associated with frequent side effects. Reports from the Nutritional Prevention of Cancer (NPC) study reported that dietary supplementation with selenium significantly reduced the risk of developing prostate cancer. These data led to initiation of the Watchful Waiting Study, a phase II, multi-center, randomized, double-blind, placebo-controlled clinical intervention study testing the effects of two doses of selenized yeast on progression of prostate cancer. Participants are men with biopsy-proven prostate cancer who have elected to forgo therapy and be closely followed by 'watchful waiting' that includes quarterly prostate-specific antigen (PSA) screening. Subjects are randomized to receive 200 or 800 microg of selenized yeast or matched placebo daily. Endpoints include time to disease progression and PSA velocity. Secondary endpoints include time to initiation of therapy as well as biochemical markers of disease progression including chromagranin A and alkaline phosphatase. Immunohistochemical analyses for indicators of apoptosis, proliferation and differentiation will be performed on baseline and subsequent prostate biopsy specimens. This report summarizes the primary objectives, research methods and the randomized subjects in this important clinical trial.

Aged↗
PubMed2003

Implementation of videoconferencing to support a managed clinical network in Scotland: lessons learned during the first 18 months.

Managed clinical networks (MCNs) are usually built on established groups of health professionals from both acute and primary care sectors. We have used videoconferencing to support the gynaecological oncology MCN in the west of Scotland. Videoconferencing was implemented simultaneously at five sites in 2001 and DICOM image-capture software was added in 2003. Videoconferencing and live PC links allowed the multidisciplinary teams to discuss individual cancer diagnoses without the extensive travelling previously required. Our experience of the implementation suggests that local ownership is crucial. In the present project, each of the stakeholders had an important role in the delivery of a successful system. High-quality project management is required during implementation and for some time thereafter to achieve sustainability.

Computer Communication Networks↗
PubMed2003

Loss of enzyme-sensitive antigens due to the presence of leukocytes, neomycin sulfate, and LISS.

Previous studies have shown that RBCs with residual WBCs stored in LISS and neomycin sulfate develop characteristics associated with enzyme-treated RBCs. During a mass screening program to antigen type donor RBCs, we observed that the Fya antigens on a RBC sample from an in-house panel became non-detectable with anti-Fya after incubation overnight in Diluent 2 from Micro Typing Systems, Inc. (MTS, Pompano Beach, FL). In response to this observation, we initiated an investigation to determine the cause. Tests were performed according to the manfacturer's instructions in MTS neutral gel cards or gel cards containing anti-IgG. We found that a reduction or loss of the Fya, Fyb, and M antigens occurs when RBCs were prepared from samples containing residual WBCs (as a source of enzymes) and subsequently incubated in media containing neomycin sulfate and LISS. We showed that the effect did not occur in the absence of neomycin sulfate. RBC antigens can be altered in LISS if they have first been exposed to neomycin. We recommend restricting the use of RBCs suspended in MTS Diluent 2 to the day of dilution (as indicated in the package insert) if preparing reagent RBCs from sources that were not leukoreduced and were stored in the presence of neomycin.

Journal Article↗
PubMed2003

Studies on the Dombrock blood group system in non-human primates.

The Dombrock blood group system consists of five distinct antigens: two antithetical antigens, Doa and Dob, and three high-frequency antigens:Gya,Hy, and Joa. Although the prevalence of Doa and Dob in different populations makes them useful as genetic markers, the scarcity of reliable antibodies to these antigens has prevented this potential from being realized. The gene (DO;ART4) encoding the Dombrock glycoprotein has been cloned and sequenced, and the molecular bases of the various Dombrock phenotypes have been determined. The purpose of this study was to perform DNA-based assays on the DO homolog in non-human primates to determine the degree of conservation in the DO gene. Murine MoAbs to Dombrock protein were developed by standard hybridoma technologies and used to test RBCs from non-human primates by hemagglutination. PCR-RFLP analysis for the six single-nucleotide polymorphisms (SNPs) that have been defined in human alleles were performed on DNA extracted from fresh or frozen blood samples from numerous non-human primates. Hemagglutination tests with six MoAbs to the Dombrock glycoprotein revealed distinct epitopes on RBCs from the non-human primates. The gorillas and orangutans had the same PCR-RFLP digestion pattern for the six SNPs studied as chimpanzees. Old world monkeys (macaques) were identical at nucleotides (nt) 323, 350, 624, and 793 with the chimpanzees, and at nt 898 the digestion pattern was the same as for the HY1 allele in humans. For the new world monkeys (tamarins and squirrel monkeys) the digestion pattern was conserved for nt 793 but different for nt 624; the other SNPs could not be determined because there was no amplification. The presence of epitopes recognized by the MoAbs and PCR-RFLP results among the non-human primates shows considerable conservation of the DO gene. The difficulties we encountered with the amplification of DNA from the non-human primates lower in the phylogenetic tree are probably due to divergence in sequence.

Journal Article↗
PubMed2003

DNA analysis for donor screening of Dombrock blood group antigens.

Due to the scarcity of reliable antibodies, RBC typing for Doa and Dob is notoriously difficult. Inaccurate typing can place patients at risk for hemolytic transfusion reactions. The molecular basis of the DOA/DOB polymorphism is associated with three nucleotide changes:378 C>T, 624 T>C,and 793 A>G of DO. While the 378 C>T and 624 T>C are silent mutations, the 793A>G polymorphism in codon 265 encodes asparagine for Doa and aspartic acid for Dob. We describe here the use of a PCR-RFLP assay as an alternative to traditional hemagglutination for typing donor blood for Dombrock. Primers were designed to amplify the region of DO containing the 793A>G polymorphism. DNA samples from blood donors were amplified and subjected to RFLP analysis. A total of 613 samples were tested for the Dombrock polymorphism (793 A>G) by PCRRFLP. PCR-RFLP can be used to screen for Do(a-) or Do(b-) donors. This approach overcomes the scarcity of the reagents required for testing by hemagglutination.

Journal Article↗
PubMed2003

Murine monoclonal antibodies can be used to type RBCs with a positive DAT.

RBCs with a positive DAT due to IgG coating require the use of directly agglutinating reagents or treatment with chemicals to remove sufficient IgG to permit typing of the RBCs with antisera that require use of the IAT. In this study we demonstrate that murine IgG MoAbs to human RBC antigens can be used as an alternative if the anti-mouse IgG is neutralized or affinity purified to prevent cross-reaction with cell-bound IgG. We performed DATs on RBC samples coated with IgG in vivo and in vitro, comparing two anti-human IgG reagents (Organon Teknika, Durham, NC, and Ortho-Clinical Diagnostics, Raritan, NJ) with two affinity-purified anti-mouse IgG reagents (The Binding Site, San Diego, CA, and Sigma, St. Louis, MO), and one non-purified anti-mouse IgG reagent. The affinity-purified anti-mouse IgG reagents were nonreactive with the four in vitro sensitized RBC samples and were nonreactive with 8 of 11 in vivo sensitized RBC samples. Non-purified antimouse IgG and both anti-human IgG reagents reacted with every sample. Use of murine MoAbs to antigen type RBCs coated with human IgG is reliable only when the anti-mouse IgG reagents have been affinity purified or neutralized to prevent cross-reactivity. Our results also show the importance of including a saline/RBC control as well as an anti-mouse IgG/RBC control. Murine MoAbs are valuable reagents and we have applied them successfully in typing patients' RBCs that have a positive DAT.

Journal Article↗
PubMed2002

The Cromer blood group system: a review.

The antigens of the Cromer blood group system reside on decay accelerating factor (DAF), a protein belonging to the regulators of complement activation family. The blood group system consists of eight high-incidence antigens and three low-incidence antigens. The molecular basis for the antigens is known and, with the exception of IFC, each antigen is the product of a single nucleotide polymorphism in the DAF gene and has been localized to one of the four short consensus repeat regions on the DAF protein. The red blood cells (RBCs) of people with the Cromer null phenotype, Inab, lack DAF. Antibodies to Cromer antigens are rarely encountered although there is evidence that the antibodies may cause accelerated destruction of transfused RBCs. There is no risk of hemolytic disease of the newborn associated with Cromer system antibodies because the placenta is a rich source of fetally derived DAF, which is thought to adsorb the antibodies.

Journal Article↗
PubMed2002

Moderate hemolytic disease of the newborn (HDN) due to anti-Rh17 produced by a black female with an e variant phenotype.

The Rh blood group antigen e is of high incidence and has many epitopes. Partial expression may occur, more commonly in black persons. Individuals with e variant phenotypes can make antibodies to epitopes they lack. While some of these antibodies may be specific for an antigen, e.g., hrB, others, like anti-Rh17 (anti-Hro), show broader specificity, compatible only with D-- and Rhnull red blood cells (RBCs). Anti-Rh17 in persons of the D-- phenotype has been reported to cause mild to fatal HDN. We report an example of anti-Rh17 produced by a black female with an e variant RBC phenotype that caused moderate HDN. A panel of seven monoclonal anti-e demonstrated her RBCs carried a variant e antigen, and her genotype was RHD, RHce by PCR-RFLP analysis. Amniotic fluid with.OD450 values from 30 to 35 weeks' gestation predicted moderate HDN probability by the Liley method. At 38+ weeks, a viable 3165 g female infant was delivered. The infant's direct antiglobulin test was 2+ with anti-IgG. Total bilirubin rose to 14.2 mg/dL within 48 hours. Indirect bilirubin peaked at 14.7 mg/dL. The bilirubin responded to triple phototherapy. The infant was discharged on day 6. Potential for infant morbidity due to anti-Rh17- mediated HDN and the importance of specifying risks to women with this antibody if they contemplate pregnancy are discussed.

Journal Article↗
PubMed2002

MIMA-9, a valuable antibody for screening for rare donors.

Since monoclonal antibodies (Mabs) are potentially available in an unlimited volume, they can be used to screen numerous donor blood samples to identify antigen-negative donors. We have used a Mab (MIMA-9) with characteristics that allow for the simultaneous screening of RBCs of any ABO group for high-incidence antigen-negativity in the Kell and Gerbich blood group systems. MIMA-9, a murine IgG2a antibody, previously shown to facilitate the identification of K+k-, Kp(a+b-), K0, McLeod, or Ge:-3 red blood cells (RBCs), was used in MTS gel cards containing anti-mouse IgG as the second antibody to test 1134 K- donors. Among the 1134 donors tested, we found one Kp(a+b-) and one Ge:-2,-3,4 donor. If random donor samples had been used instead of preselecting for K-, we would have expected to identify two K+k- donors. One reagent (MIMA-9) can be used to simultaneously screen for K+k-, Kp(a+b-), K0, McLeod, and Ge:-3 RBCs and thereby conserve rare antisera. Inclusion of anti-mouse IgG in gel cards allowed for rapid screening. MIMA-9 is also a useful reagent to type RBCs with a positive direct antiglobulin test. This antibody is available to donor screening laboratories at no cost for this specific use.

Journal Article↗
PubMed2002

Confirmation that the JAHK antigen is associated with the rG haplotype.

Anti-JAHK, an antibody directed toward a low-incidence antigen in the Rh system, was detected during routine antibody identification in a male donor who had no history of transfusion. Examples of anti-JAHK have been found in sera containing multiple antibodies to low-incidence antigens. The first report of anti-JAHK was in 1995 and described the association of the JAHK antigen with the rG haplotype. Our results confirm this association.

Journal Article↗
PubMed2001

Characterization of a Plasmodium falciparum erythrocyte-binding protein paralogous to EBA-175.

A member of a Plasmodium receptor family for erythrocyte invasion was identified on chromosome 13 from the Plasmodium falciparum genome sequence of the Sanger Centre (Cambridge, U.K.). The protein (named BAEBL) has homology to EBA-175, a P. falciparum receptor that binds specifically to sialic acid and the peptide backbone of glycophorin A on erythrocytes. Both EBA-175 and BAEBL localize to the micronemes, organelles at the invasive ends of the parasites that contain other members of the family. Like EBA-175, the erythrocyte receptor for BAEBL is destroyed by neuraminidase and trypsin, indicating that the erythrocyte receptor is a sialoglycoprotein. Its specificity, however, differs from that of EBA-175 in that BAEBL can bind to erythrocytes that lack glycophorin A, the receptor for EBA-175. It has reduced binding to erythrocytes with the Gerbich mutation found in another erythrocyte, sialoglycoprotein (glycophorin C/D). The interest in BAEBL's reduced binding to Gerbich erythrocytes derives from the high frequency of the Gerbich phenotype in some regions of Papua New Guinea where P. falciparum is hyperendemic.

Animals↗
PubMed2001

A DNA-based immunization protocol to produce monoclonal antibodies to blood group antigens.

A major challenge facing transfusion medicine is the establishment of immunological methods to produce specific and avid blood group typing reagents to the many polymorphic blood group antigens. This is especially true when sources of human antibody are limited. Based on the knowledge that inoculation with plasmid DNA can induce a humoral response in the host animal, we inoculated mice with plasmid DNA followed by a single boost injection with plasmid-transfected cells that have a high level of expression of the same target protein. Using this method, several hybridoma clones that produced strongly reactive antibodies specific for the Kell polymorphic antigens (anti-K, anti-k, anti-Kp(a)) were isolated. The monoclonal antibodies that were produced with this method have potential clinical utility for identifying a patient's blood type and for screening for antigen-negative donor blood.

Animals↗