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Biomedical subjects

M E Reid

Publications and source records attributed to M E Reid.

At least 127 records · Page 7Linked to original sources
PubMed1996

Should obstetricians see women with normal pregnancies? A multicentre randomised controlled trial of routine antenatal care by general practitioners and midwives compared with shared care led by obstetricians.

OBJECTIVE: To compare routine antenatal care provided by general practitioners and midwives with obstetrician led shared care. DESIGN: Multicentre randomised controlled trial. SETTING: 51 general practices linked to nine Scottish maternity hospitals. SUBJECTS: 1765 women at low risk of antenatal complications. INTERVENTION: Routine antenatal care by general practitioners and midwives according to a care plan and protocols for managing complications. MAIN OUTCOME MEASURES: Comparisons of health service use, indicators of quality of care, and women's satisfaction. RESULTS: Continuity of care was improved for the general practitioner and midwife group as the number of carers was less (median 5 carers v 7 for shared care group, P<0.0001) and the number of routine visits reduced (10.9 v 11.7, P<0.0001). Fewer women in the general practitioner and midwife group had antenatal admissions (27% (222/834) v 32% (266/840), P<0.05), non-attendances (7% (57) v 11% (89), P<0.01) and daycare (12% (102) v 7% (139), P<0.05) but more were referred (49% (406) v 36% (305), P<0.0001). Rates of antenatal diagnoses did not differ except that fewer women in the general practitioner and midwife group had hypertensive disorders (pregnancy induced hypertension, 5% (37) v 8% (70), P<0.01) and fewer had labour induced (18% (149) v 24% (201), P<0.01). Few failures to comply with the care protocol occurred, but more Rhesus negative women in the general practitioner and midwife group did not have an appropriate antibody check (2.5% (20) v 0.4% (3), P<0.0001). Both groups expressed high satisfaction with care (68% (453/663) v 65% (430/656), P=0.5) and acceptability of allocated style of care (93% (618) v 94% (624), P=0.6). Access to hospital support before labour was similar (45% (302) v 48% (312) visited labour rooms before giving birth, P=0.6). CONCLUSION: Routine specialist visits for women initially at low risk of pregnancy complications offer little or no clinical or consumer benefit.

Clinical Protocols↗
PubMed1996

Disappearance of antibodies to Cromer blood group system antigens during mid pregnancy.

The Cromer blood group system consists of 7 high incidence and 3 low incidence antigens that are carried on the complement regulatory glycoprotein called decay-accelerating factor (DAF; CD55). Despite laboratory results that would predict clinical significance, antibodies with specificities in the Cromer blood group system have not been reported to cause hemolytic disease of the newborn. It is possible that strong expression of DAF on the apical surface of antigen-positive fetally derived placental trophoblasts may absorb maternal antibodies that are directed to antigens in the Cromer blood group system. We studied two cases where strongly reactive anti-Cra and anti-Dra became undetectable during second and third trimesters of pregnancies.

Blood Group Antigens↗
PubMed1996

Characterization of antibodies produced by S-s- individuals.

BACKGROUND: Historically, classification of U- and U variant (U+var) individuals has been made by hemagglutination and adsorption and elution studies performed with polyclonal U antisera. Molecular studies and serologic tests with a potent monoclonal anti-He have shown that U+var red cells, some of which are He+, possess an altered form of glycophorin B. STUDY DESIGN AND METHODS: Seventeen sera, previously determined to contain anti-U, were tested with a panel of red cells of common and rare MNS types. RESULTS: Five sera contained anti-U only, and 12 sera contained broadly reactive antibodies with apparent, but inseparable, anti-U,He or anti-U,N,He specificities. CONCLUSION: The majority of antibodies produced by S-s-U- individuals are anti-U plus anti-glycophorin B and are analogous to the broadly reactive antibodies produced by En(a-) individuals whose red cells lack glycophorin A or have altered glycophorin A. To avoid further immunization of patients with anti-U, sera used for classification of S-s-U- donors should be selected to detect S-s- red cells that possess altered forms of glycophorin B.

Antibody Specificity↗
PubMed1996

Expression and quantitative variation of the low-incidence blood group antigen He on some S-s-red cells.

BACKGROUND: Red cells devoid of glycophorin B (GPB)-borne S, s, and U antigens are classified as an S-s-U- or S-s-U variant (U+var) and can arise from deletion and nondeletion genetic backgrounds. In nondeletion forms of S-s-U-, little information is available on whether the altered GPB gene (GYPB) is expressed in red cells. STUDY DESIGN AND METHODS: Red cells classified as S-s-U- or S-s-U+var were tested with anti-U, anti-U/GPB, anti-He, and anti-N by hemagglutination. Selected samples were tested by flow cytometry, immunoblotting, and polymerase chain reaction amplification using allele-specific primers. RESULTS: He (MNS6) was found on 23 percent (20/87) of samples. These and another 21 of the 87 samples were agglutinated by an anti-U/GPB reagent; this indicated that approximately 50 percent of S-s-samples possessed GPB variants. The strength of He varied among the samples. Genomic polymerase chain reaction with allele-specific primers showed the presence of expected DNA GPB-like products encoding He. Immunoblotting showed that He was carried on a membrane component with a relative molecular mass indistinguishable from that of GPB. CONCLUSION: The finding of He on S-s- red cells provides direct evidence for the presence of an altered form of GPB in red cells previously thought to be devoid of this glycophorin. Quantitative variation in He antigen expression was observed in a subset of S-s- red cells.

Animals↗
PubMed1996

Effect of pronase on high-incidence blood group antigens and the prevalence of antibodies to pronase-treated erythrocytes.

Pronase is a useful and relatively nonspecific protease that cleaves many red blood cell (RBC) membrane proteins that carry blood group antigens. Unexpected findings in tests using pronase-treated RBCs during the investigation of a patient's blood sample led us to test which high-incidence blood group antigens were sensitive and which were resistant to pronase treatment, and to determine the prevalence of antipronase in the serum of blood donors. Our results show that antigens in the Cromer and Lutheran blood group systems and the JMH antigen were sensitive to pronase treatment of RBCs. Antigens in the Dombrock blood group system and Sc1 were either sensitive to or markedly weakened by pronase treatment of RBCs. The following high-incidence antigens were resistant to treatment of RBCs with pronase: AnWj, Ata, Coa, Co3, Dib, EnaFR, Era, Fy3, Jk3, Jra, k, Kpb, Jsb, K14, Lan, Oka, Rh17, U, Vel, and Wrb. Over half of the serum samples from normal blood donors contained antibodies to pronase-treated RBCs. When testing human serum against pronase-treated RBCs, it is essential either to use an autocontrol or to perform the testing with an eluate.

Journal Article↗
PubMed1996

A method to detect McLeod phenotype red blood cells.

It is important to identify the McLeod phenotype in order to differentiate the McLeod syndrome from other causes of acanthocytosis, e.g., chorea acanthocytosis. A proportion of males with the McLeod phenotype have X-linked chronic granulomatous disease. Because anti-Kx + -Km, which is needed for identification, is not readily available, detection of the McLeod phenotype relies on observed weakening of Kell antigens on the individual's red blood cells (RBCs). Identification of McLeod carrier females (obligate heterozygotes) is even more difficult because only a minor subpopulation of RBCs may express the weakened Kell phenotype. RBCs from 12 sets of mother/son or father/daughter pairs were tested by standard hemagglutination tube tests and by flow cytometry using both monoclonal and polyclonal Kell system antibodies. Monoclonal anti-K14 (G10) in tests with RBCs from McLeod males reacted +/- by hemagglutination (control cells 2+) and had a median fluorescence of 6-11 by flow cytometry (control cells 441). Monoclonal anti-k (F7) and human polyclonal anti-k (C30A-1) gave stronger reactions by hemagglutination with RBCs from McLeod males and were not appropriate to differentiate RBCs with the McLeod phenotype from RBCs with normal Kell antigen expression. Crisp mixed-field agglutination was obtained in tests with monoclonal anti-K14 versus RBCs from the 12 obligate carrier females. Flow cytometry using anti-K14 also clearly identified two RBC populations (median fluorescence of 6-11 and 229-382, respectively). Kell system antibodies may vary in their ability to detect a weakened expression of the corresponding antigen on RBCs with the McLeod phenotype by hemagglutination. Antibodies suitable for differentiating McLeod syndrome from other forms of acanthocytosis should be reagents that are preselected after extensive testing. In this study, flow cytometry clearly identified the two RBC populations in McLeod carrier females.

Journal Article↗
PubMed1996

A second example of anti-Esa, an antibody to a high-incidence Cromer antigen.

A blood sample contained an antibody to a high-incidence antigen that reacted with all red blood cells (RBCs) tested by the indirect antiglobulin test (IAT). The antibody reacted with papain-, ficin-, and trypsin-treated RBCs, but not with a-chymotrypsin-treated RBCs. This pattern of reactivity suggested the possibility that the antibody was recognizing an antigen in the Cromer blood group system. Tests against RBCs deficient in decay-accelerating factor (which carries the Cromer antigens) were weakly positive. Tests with antibodies to high-incidence Cromer antigens and with RBCs lacking high-incidence Cromer antigens led to identification of the second example of anti-Esa in an Es(a-) person. The antibody was IgG1 and reacted by the IAT to a titer of 64. The monocyte monolayer assay indicated potential clinical significance of this antibody in relation to transfusion.

Journal Article↗
PubMed1996

Characterization of human anti-hrB-like monoclonal antibody.

To develop a blood typing reagent with Rh specificity, peripheral blood lymphocytes were isolated from a multiparous woman with apparent alloanti-Ce and fused with FIS heteromyeloma cells. One hybridoma cell line, FOR-2E3, secreted human IgG, which agglutinated all human red blood cells except R2R2, RZRZ, Dc-, D--, Rhnull, and e+ hrB-. The supernatant is useful as a reagent to screen for hrB- blood donors and to differentiate haplotypes with C and e in cis from haplotypes with C and e in trans.

Journal Article↗
PubMed1996

The second example of Lu:-7 phenotype: serology and immunochemical studies.

We describe the second example of red blood cells (RBCs) with the Lu:-7 phenotype in a 37-year-old Latino female (SA). Her RBCs were nonreactive with anti-Lu7 (Mrs. GA) but were reactive with all other antibodies to high-prevalence antigens tested, including those in the Lutheran blood group system. No Lu:-7 RBCs were available for testing. SA's serum was nonreactive by the indirect antiglobulin test against (1) recessive and dominant Lu(a-b-) RBCs and (2) trypsin-treated or a-chymotrypsin-treated RBCs of common phenotype. By immunoblotting, eluates containing anti-Lu7 from both Mrs. GA and SA reacted with apparently the same bands in RBC membranes of common phenotype as did human anti-Lub, reacted weakly with Lu(a-b-) RBCs of the dominant type, and were nonreactive with SA's RBC membranes. These findings raise the Lu7 antigen from its Lutheran-related (para-Lutheran) status to a bona fide member of the Lutheran blood group system.

Journal Article↗
PubMed1996

Glycophorin A-deficient red cells may have a weak expression of C4-bound Ch and Rg antigens.

The blood group antigens Ch and Rg are polymorphisms of C4d. Antigen-positive red blood cells (RBCs) treated with proteases type as Ch-, Rg-. Although RBCs treated with sialidase may type Ch+ Rg+, they cannot be coated with C4 by the 10 percent sucrose method. Since studies of complement binding have shown that glycophorin A (GPA) is an important component for the uptake of C4 by RBCs, we tested all available GPA-deficient RBCs for their Ch and Rg status. Using eluates of human anti-Ch and anti-Rg, and monoclonal anti-Rg, we found that the Ch antigen was only weakly expressed on these RBCs, while Rg expression was variable. Our results imply that in the absence of GPA, C4 binds in vivo to a component or components other than GPA on RBCs.

Journal Article↗
PubMed1996

Molecular definition of red cell Rh haplotypes by tightly linked SphI RFLPs.

The Rh blood group system of human red cells contains five major antigens D, C/c, and E/e (the latter four designated "non-D") that are specified by eight gene complexes known as Rh haplotypes. In this paper, we report on the mapping of RH locus and identification of a set of SphI RFLPs that are tightly linked with the Rh structural genes. Using exon-specific probes, we have localized the SphI cleavage sites resulting in these DNA markers and derived a comprehensive map for the RH locus. It was found that the SphI fragments encompassing exons 4-7 of the Rh genes occur in four banding patterns or frameworks that correspond to the distribution and segregation of the common Rh haplotypes. This linkage disequilibrium allowed a genotype-phenotype correlation and direct determination of Rh zygosity related to the Rh-positive or Rh-negative status (D/D, D/d, and d/d). Studies on the occurrence of SphI RFLPs in a number of rare Rh variants indicated that Rh phenotypic diversity has taken place on different haplotype backgrounds and has arisen by diverse genetic mechanisms. The molecular definition of Rh haplotypes by SphI RFLP frameworks should provide a useful procedure for genetic counseling and prenatal assessment of Rh alloimmunization.

Base Sequence↗
PubMed1995

Identification of a partial internal deletion in the RH locus causing the human erythrocyte D--phenotype.

The D--phenotype of the human erythrocyte is a genetic variant of the Rh blood group system associated with the expression of D but not C, c, E, and e (designated non-D) antigens. In this report, we characterize the structure and expression of Rh polypeptide genes in two D--homozygotes of Italian origin. Southern blot analysis detected a gross deletion in their genomic DNA that correlated with the alteration of CcEe rather than the D polypeptide gene. With detailed exon mapping, the deletion was found to be partial and internal, encompassing exons 2 through 8 of the non-D gene. Analysis of Rh cDNAs showed that no functional mRNA was produced from the truncated non-D gene, whereas the D gene gave rise to one major and two minor mature transcripts. The full-length RhD cDNA sequence contained four nucleotide changes resulting in four amino acid substitutions on the polypeptide backbone. The shortened RhD cDNAs occurred as alternatively spliced isoforms lacking sequences corresponding to exons 7 and/or 8. The identification of a partial and internal deletion in the non-D gene shows that the molecular basis for the D--phenotype is heterogenous and that its alterations have occurred on different genetic backgrounds.

Amino Acid Sequence↗
PubMed1995

Glycophorin SAT of the human erythrocyte membrane is specified by a hybrid gene reciprocal to glycophorin Dantu gene.

Previous studies of two unrelated Japanese families showed that two isoforms of glycophorin were associated with the expression of SAT antigen on the erythrocyte membrane. Here we report the molecular basis for one form of this MNSs-related surface marker that displayed an altered immunoblotting pattern. Evidence is presented that glycophorin SAT (GPSAT) is encoded by a hybrid gene resulting from unequal homologous recombination between GPA and GPB genes. Analysis of SAT genomic DNAs by Southern blots showed gross alterations in the glycophorin gene cluster. Those restriction fragments characteristic of the GPA 3' and GPB 5' ends were absent from the SAT homozygote and showed reduced intensity in SAT heterozygotes. Reticulocyte RNA polymerase chain reaction showed the presence in the SAT homozygote of GPSAT and GPE transcripts but no GPA and GPB transcripts. Direct sequencing of the amplified SAT cDNA showed that its sequence from exon I to exon IV was identical with the N allele of GPA, whereas its 3' portion, including exon V and exon VI, was derived from the GPB gene. The GPSAT protein in its mature form should contain 104 amino acid residues and bear a novel sequence, Ser-Glu-Pro-Ala-Pro-Val, encoded by the junction of GPA exon IV and GPB exon V. This sequence interfaces the extracellular and transmembrane domains and could be the epitope site of the SAT antigen. The formation of such a hybrid junction not only explains why SAT homozygous erythrocytes lack S, s, and U antigens but also shows a reciprocal arrangement with respect to the B-A hybrid GPDantu gene.

Amino Acid Sequence↗
PubMed1995

Changes in the blood group Wright antigens are associated with a mutation at amino acid 658 in human erythrocyte band 3: a site of interaction between band 3 and glycophorin A under certain conditions.

The Wright (Wr) blood group antigens, Wra and Wrb, have been suggested to be determined by alleles of the same gene. The Wrb antigen appears to involve both red blood cell (RBC) band 3 and glycophorin A (GPA). We have examined the cDNA sequences of the band 3 and GPA of one of the two known Wr(a+b-) individuals. We show that this individual is homozygous for the mutation Glu658-->Lys in band 3, but has normal GPA. Putative heterozygotes with Wr(a+b+) RBCs have both Glu and Lys at residue 658 of band 3, whereas the common Wr(a-b+) RBC phenotype only have band 3 with Glu658. The Wra and Wrb antigens are determined by the amino acid at residue 658 of band 3 and are antithetical. Examination of the amino acid sequence and Wrb antigen expression of GPA-related hybrid glycophorins suggests that Arg61 of GPA interacts with Glu658 of band 3 to form the Wrb antigen. We suggest that the interaction is stabilized by the presence of anti-Wrb antibodies and that this site of association between GPA and band 3 may be responsible for the previously reported ability of anti-GPA antibodies to decrease the deformability of RBCs.

Alleles↗
PubMed1995

Selective protection against IgG binding to red cells treated with phthalocyanines and red light for virus inactivation.

BACKGROUND: Irradiation with red light of red cells (RBCs) containing the photodynamically active phthalocyanine (Pc) dyes is being studied for inactivation of lipid-enveloped viruses. One of the outstanding problems with this treatment is the binding of IgG to RBCs. The effects of oxygen and type I or type II quenchers on this IgG uptake were evaluated. STUDY DESIGN AND METHODS: The Pc compounds used were aluminum phthalocyanine tetrasulfonate (AIPcS4), HOSiPcOSi(CH3)2(CH2)3N(CH3)2 (Pc 4); HOSiPcOSi(CH3)2(CH2)3N+(CH3)3I- (Pc 5); and SiPcOSi[(CH3)2(CH2)3N+(CH3)3](2)2I- (Pc 6). RBCs were analyzed by flow cytometry for the presence of IgG. RESULTS: Irradiation with red light for 30 minutes of RBCs containing either 2 microM Pc 4, 2 microM Pc 5, 2 microM Pc 6, or 6.5 microM AIPcS4 resulted in an uptake of IgG. These conditions completely inactivated the lipid-enveloped vesicular stomatitis virus (VSV) (> 5 log10 kill). IgG uptake was reduced when oxygen was depleted. The addition of reduced glutathione (GSH) or mercaptoethanol prevented the binding of IgG with RBCs treated with AIPcS4, Pc 4, Pc 5, and Pc 6. Specific binding of IgG2 but not of C3d was observed upon irradiation of RBCs with Pc 5 and Pc 6 in the absence of GSH. No gross changes were observed in RBC antigen strength after irradiation with the dyes in the presence of GSH. Inactivation of VSV by Pc plus light was not affected by GSH. CONCLUSION: Sulfhydryl compounds are useful in preventing IgG binding to RBCs following Pc photosensitization. Since virus inactivation proceeds at the same rate in the presence and the absence of sulfhydryl compounds, their addition to treated RBCs should allow crossmatching for transfusion after treatment. The binding of IgG depends to a large extent on the generation of reactive oxygen species.

Antiviral Agents↗
PubMed1995

Investigations using a novel monoclonal antibody to the glycosylphosphatidylinositol-anchored protein that carries Gregory, Holley, and Dombrock blood group antigens.

BACKGROUND: The high-frequency Hy and Gya antigens have been shown to reside on the same protein. Gy(a-) Hy-negative red cells are also Do(a-b-). A mouse monoclonal antibody, 5B10, was produced with specificity related to the human Gregory, Holley, and Dombrock blood group antigens. STUDY DESIGN AND METHODS: The antibody reacted in direct hemagglutination assays, and its specificity was investigated by radioimmunoassay, inhibition assay, and Western blotting. RESULTS: The 5B10 antibody failed to bind to abnormal paroxysmal nocturnal hemoglobinuria red cells and human erythroleukemia cell line K562, but it was weakly reactive with HEL cells. Red cells, but not other circulating hematopoietic cells, express the 5B10 antigen. The 5B10 antibody had a specificity similar but not identical to that of Gya. Gy(a-) Hy-negative red cells reacted extremely weakly with 5B10 antibody, but Gy(a-) Hy-negative red cells treated with a variety of proteases bound 5B10 antibody strongly. This suggests that these cells express a variant form of the protein recognized by 5B10. CONCLUSION: Identification of a monoclonal antibody to this glycosylphosphatidylinositol-linked protein opens a new avenue for investigation of the biochemistry, genetics, and function of the glycosylphosphatidylinositol-linked protein that bears the Gya, Hy, and Do antigens.

Alleles↗
PubMed1995

Reactivity with erythroid and non-erythroid tissues of a murine monoclonal antibody to a synthetic peptide having amino acid sequence common to cytoplasmic domain of human glycophorins C and D.

Three synthetic peptides encompassing the entire cytoplasmic polypeptide sequence (amino acid residues 82-128) of glycophorin C (GPC) and glycophorin D (GPD) were used to immunize mice for the production of monoclonal antibodies (MoAbs). Only the synthetic peptide (GPC-peptide-1) corresponding to C-terminal residues 112-128 elicited a MoAb (named BGRL-100) which could react with native and denatured GPC and GPD. We characterized BGRL-100 by inhibition using GPC-peptide 1 and red cell sialoglycoproteins. The ability of BGRL-100 to interact with native GPC and GPD was assessed by immunoprecipitation with normal red cells (RBCs), and with denatured GPC and GPD by Western blotting of both normal RBCs and RBCs carrying GPC variants. Immunohistochemical staining of human tissue sections was performed using both BGRL-100 and a rat MoAb (named BRAC-1), which is specific for an extracellular domain of GPC and GPD. Both antibodies showed strong staining of erythroid lineage haemopoietic cells in fetal liver, sinusoids of adult liver and RBCs in the blood vessels of all tissues tested. Neither antibody reacted with epithelia from a range of human tissues. However, both MoAbs stained neural tissue in a distinctive fibrillar pattern. This suggests the presence of an analogue of erythroid GPC in neural tissues.

Amino Acid Sequence↗