PubMed Health⌕ Search

Biomedical subjects

E A Robinson

Publications and source records attributed to E A Robinson.

At least 55 records · Page 3Linked to original sources
PubMed1986

Characterization of a chemically homogeneous tumor antigen from a methylcholanthrene-induced sarcoma, Meth A.

A tumor antigen isolated from the cytosol of a methylcholanthrene-induced sarcoma (Meth A) has been purified to homogeneity by the criteria of two-dimensional gel analysis and NH2- and COOH-terminal sequencing. The purified antigen has a mol. wt of 82,000 by SDS gel electrophoresis. However, the apparent mol. mass of the antigen was found to be 71,600 and 67,700 by gel filtration chromatography and sedimentation analysis, respectively. It is not a glycoprotein, possesses an acidic isoelectric point (6.0) and exists as dimeric and monomeric species. The dimer is not held together by disulfide bonds. The purified protein retains its ability to induce transplantation immunity in syngeneic hosts when challenged with Meth A sarcomas. Chemical analyses of the NH2- and COOH-termini gave the following sequences: NH2-PKPINVRVTTMDAELEFAIQPN and IDE(F,A)EM-COOH, respectively.

Amino Acid Sequence↗
PubMed1986

A mouse tumor-specific transplantation antigen is a heat shock-related protein.

A tumor-specific transplantation antigen has been purified to homogeneity from the cytosol of a methylcholanthrene-induced tumor, Meth A. The purified antigen is highly immunogenic and specific against challenge with Meth A, providing greater than 95% inhibition of tumor growth in immunized syngeneic mice. Immunofluorescence analysis of Meth A showed that the antigen is a highly abundant cytosolic protein but that it is also present at the cell surface and, therefore, accessible to the host's immune system. The antigen consists of two polypeptide isoforms present in equimolar amounts, having similar masses (84 and 86 kDa), pI values (4.95 and 4.90), and amino acid compositions. Both are phosphoproteins, and neither is glycosylated. The NH2-terminal sequences of the two isoforms are identical except that each chain contains a portion of unique sequence. Comparison of the NH2-terminal and CNBr-fragment sequence data to the sequences of the yeast and Drosophila heat shock proteins (Hsp90 and Hsp83, respectively) reveals that 73 of 91 residues compared are identical. In addition, an anti-Meth A tumor antigen serum that defects the isoforms from a variety of tumors also immunoprecipitates proteins of identical mass and pI from both normal and heat-shocked mouse embryo cells.

Amino Acid Sequence↗
PubMed1985

Changes in plasma fibronectin during donor apheresis and therapeutic plasma exchange.

Changes in plasma levels of the opsonic glycoprotein fibronectin were studied during machine apheresis in 32 healthy plasma donors and 18 patients undergoing a total of 86 therapeutic plasma exchanges. Donation of 500 ml of plasma at 3-monthly intervals produced a 10% immediate decrease in plasma fibronectin with no evidence of a long-term affect on levels of this protein. One plasma volume exchange with fibronectin-poor plasma protein fraction produced subnormal plasma fibronectin levels in 98% of post-exchange samples. Efficiency of exchange was significantly lower in patients with paraproteinaemia, probably reflecting increased plasma volume in such patients. Daily plasma exchange produced progressive depletion of plasma fibronectin (index of recovery 0.68) whereas levels were maintained close to the initial value with longer exchange intervals, except in the more severely ill patients. Reduction of plasma fibronectin by plasma exchange may increase susceptibility to infection and reduce the efficacy of this procedure when the object of exchange is to reverse reticuloendothelial blockade.

Adult↗
PubMed1985

Speed of relapse in children with acute lymphoblastic leukaemia.

16 children with acute lymphoblastic leukaemia (ALL) who relapsed on maintenance treatment between September 1978 and December 1981 were studied. Their previous bone marrow aspirates were reviewed to determine the first evidence for marrow relapse and the subsequent rate of evolution of the disease. 60% of children had bone marrow evidence of unsuspected relapse at 8 wk, and 40% had evidence at 12 wk before clinical or peripheral blood relapse occurred. Early detection of relapse will prevent continued use of ineffective maintenance chemotherapy and may also reduce morbidity during subsequent induction therapy. Regular 8-weekly marrow aspirates are therefore recommended during first remission of ALL in children with a histocompatible sibling who would be eligible for bone marrow transplantation in second remission.

Bone Marrow Examination↗
PubMed1984

Amino acid sequence of a segment of the Acanthamoeba myosin II heavy chain containing all three regulatory phosphorylation sites.

The actin-activated Mg2+-ATPase activity of myosin II from the soil amoeba Acanthamoeba castellanii is regulated by phosphorylation of 3 serine residues on the myosin II heavy chain. Partial chymotryptic digestion of 32P-labeled myosin II cleaves from the tail end of the myosin II heavy chain a small peptide which contains all three phosphorylation sites. During purification the phosphorylated peptide is resolved into several different species as a result of heterogeneity both in phosphate content and in size (probably due to chymotryptic cleavage at the carboxyl terminus). However, all forms of the peptide have an identical amino terminus. The sequence of the first 58 residues of the peptide is: N-S-A-L-E-S-D-K-Q-I10-L-E-D-E-I-G-D-L-H- E20-K-N-K-Q-L-Q-A-K-I-A30-Q-L-Q-D-E-I-D-G-T- P40-S-S-R-G-G-S-T-R-G-A50-S-A-R-G-A-S-V-R. The phosphorylated serines are at positions 46, 51, and 56. The first 36 residues of the sequence display a repeating 3-4-3-4 pattern of hydrophobic residues suggesting that this section of the peptide forms an alpha-helical coiled-coil structure. A -Gly-Thr-Pro sequence at residues 38-40 disrupts the alpha-helix and, at the same point, the repeating pattern of non-polar residues is lost. It is likely that the residues extending from Gly-38 to the end of the myosin II tail, which include the 3 phosphorylatable serines, form a randomly coiled or small globular structure. This is the first report of the sequence around the regulatory phosphorylation sites on any myosin heavy chain.

Adenosine Triphosphatases↗
PubMed1984

Low molecular weight plasma proteins in the cerebrospinal fluid of children with hematological malignancies.

The concentration of beta-2-microglobulin (beta 2-m) and of post gamma globulin (P gamma G) was examined in serum and cerebrospinal fluid from children with acute lymphatic leukemia (ALL) and non-Hodgkin's lymphoma (NHL). Data were analysed in order to determine whether concentration of beta 2-m or P gamma G during remission would be of value in predicting relapse or eventual outcome. Mean serum concentration of beta 2-m was similar in good and poor prognosis patients with ALL in remission and was not significantly altered in CNS or marrow relapse. Mean CSF concentration in NHL was also similar in both prognostic groups, and in poor prognosis patients was not significantly altered in relapse. The same pattern was seen when P gamma G was measured in CSF (serum concentration of this protein being too low for accurate determination). High within patient variability of levels of beta 2-m and P gamma G appeared to relate to chemotherapy rather than the disease process. Concentration of P gamma G was persistently raised in three children with brain damage of differing etiologies. Levels of two other low molecular weight proteins, retinol binding protein and alpha 1-microglobulin, were also determined in order to establish that beta 2-m and P gamma G concentration was not influenced by alteration in permeability of the blood-brain barrier. The beta 2-m and P gamma G concentration, although higher than reported in healthy children [5] does not appear to be of value as a prognostic indicator in ALL and NHL in children.

Adolescent↗
PubMed1983

Family adjustment, parental attitudes, and social desirability.

This study examines the role of social desirability response set on the report of marital adjustment, child adjustment, and parenting attitudes. Results from 69 married couples closely replicate previous self-report findings suggesting that the more positive the report of marital adjustment, the fewer the number of child problem behaviors endorsed by parents (r = -.19(69), p less than .05). When social desirability is controlled, however, the marital-child adjustment relationship is nonsignificant. Previous reports of a global relationship between marital and child adjustment may have been inflated by individual differences in willingness to endorse problems on self-report measures. Parenting attitudes are not associated with social desirability or marital adjustment. Warmth, but not authoritarianism, is negatively correlated with child behavior problems in the home (r = -.25(69), p less than .01). The authors propose that family interaction research use a multimethod strategy to focus on circumscribed variables that influence marital and parenting behavior.

Adolescent↗
PubMed1983

Parent-child interaction training for parents with a history of mental retardation.

The purpose of the present report was to describe parent-child interaction among families with a history of parental retardation and to explore the possibility of modifying the interaction through parent training. Subjects were six parents who attended eight small group sessions designed to teach relationship building skills. Parents learned to describe, praise, and reflect and to interact nondirectively by refraining from commands during play sessions with their child. Parents decreased directiveness (p less than .01) and increased positive verbal behavior (p less than .01) between pretraining and posttraining, but at one-month follow-up only the decrease in directiveness was maintained (p less than .01). Mentally retarded parents at follow-up were similar to a normative comparison group in number of praises used, but continued to lag behind in descriptive statements. Results suggested that parents with a history of mental retardation can acquire subtle attentional skills, but that they continue to use only the nondirective skills when training is discontinued. It was concluded that additional efforts to understand family interaction patterns and to provide parent training for parents with a history of mental retardation are worthwhile.

Adult↗
PubMed1983

Comparison of the effects of filtration leucapheresis and discontinuous flow centrifugation leucapheresis on granulocyte microbicidal function.

In an investigation of the in vitro phagocytic and microbicidal function of granulocytes collected by filtration leucapheresis (FL) from 18 donors and by discontinuous flow centrifugation leucapheresis (DFC) from six donors, comparison was made with the function of granulocytes obtained from the same donors by venepuncture and density gradient centrifugation over Ficoll-Isopaque (FI). No significant impairment of the phagocytosis or killing of Candida guilliermondii by either FL- or DFC-granulocytes was observed. Although the ability of FL-granulocytes to phagocytose and kill Staphylococcus aureus did not differ significantly from the function of control FI-granulocytes, DFC-granulocytes were significantly less active.

Adult↗
PubMed1982

Purification and characterization of mouse beta-2 microglobulin: allelic variants from two different strains.

Beta-2 microglobulin (beta 2M) is a 12,000 dalton protein associated with membrane-bound cell surface antigens. Variants of beta 2M, beta 2MA and beta 2MB, were first detected by Michaelson et al. (Immunogenetics 11, 93-95, 1980). An improved method was used to purify beta 2MA and beta 2MB from BALB/c and C57BL/6 mouse livers, respectively. Reproducible yields of 10% were obtained. The purifications were accomplished by a 3 M sodium thiocyanate (NaSCN) extraction of a crude membrane fraction, an acid precipitation step, gel filtration on Sephadex G-75 and ion-exchange chromatography on DEAE-cellulose and CM-cellulose in that order. The elution profile of beta 2MA and beta 2MB on the ion-exchange columns was found to be different, indicating the presence of structural changes. beta 2MA was found to be more acidic (pI = 7.35) than beta 2MB (pI = 7.68) by isoelectric focusing in gels. Complete sequence analysis of beta 2MA and partial sequence analysis of beta 2MB (61 of 99 residues) were performed by automated Edman degradation of the intact chain and of the overlapping peptides obtained by: (a) tryptic cleavage at arginines after acetimidation of lysine side chains, (b) BNPS-skatole cleavage at tryptophan residues and (c) hydroxylamine cleavage at asparagine-glycine linkages. A comparison of the primary structure of beta 2MA to the partial amino acid sequence obtained for beta 2MB revealed a single amino acid substitution (aspartic acid for alanine at position 85) that accounts for the differences in biochemical properties observed.

Alleles↗
PubMed1982

Complete sequence analysis of cDNA clones encoding rat whey phosphoprotein: homology to a protease inhibitor.

Lactoprotein clones have been isolated from a rat mammary gland recombinant library of cDNA plasmids. Clones p-Wp 52 and p-Wp 47 were shown by hybrid selection, in vitro translation, and immunoprecipitation to represent a cloned DNA sequence encoding rat whey phosphoprotein. We report here the nucleotide sequence of the cDNA insert of p-Wp 52 and shows that it encodes the complete whey phosphoprotein sequence. The encoded sequence shows a high content of half-cystine, glutamic acid, aspartic acid, and serine but an absence of tyrosine. The half-cystines appear in unique arrangements and are repeated in two domains of the protein. The second domain has striking similarities with the second domain of the red sea turtle protease inhibitor. Clone p-Wp 52 has allowed the study of expression of whey phosphoprotein mRNA during functional differentiation of rat mammary gland and in mammary tumors. The whey phosphoprotein mRNA is detected during midpregnancy and lactation in the rat mammary gland but is barely detected in mammary tumors in which other milk protein mRNAs are expressed. The whey phosphoprotein gene in these tumors is hypermethylated, correlating with the reduced expression of this gene.

Amino Acid Sequence↗
PubMed1982

Multiple gamma-crystallins of the mouse lens: fractionation of mRNAs by cDNA cloning.

cDNAs made from polyadenylylated RNAs of the mouse lens were cloned by the G.C tailing procedure in the bacterial plasmid pBR322. Four recombinant DNAs containing gamma-crystallin sequences were identified by hybrid selection and translation. Sequence analysis of the in vivo-labeled gamma-crystallin polypeptides that cofocused isoelectrically with the hybrid-selected translation products established that the four cloned cDNAs were derived from mRNAs encoding gamma-crystallin polypeptides with similar NH2 termini. The cDNA clones had different restriction maps and could discriminate among the different gamma-crystallin mRNAs under stringent hybridization conditions. Under relaxed hybridization conditions, the cDNA clones cross-hybridized with all gamma-crystallin mRNAs, and even slightly with beta-crystallin mRNAs, as judged by in vitro translation. RNA blot hybridization showed that the mouse lens gamma-crystallin mRNAs are 840 +/- 100 nucleotides long. These data indicate that there are at least four similar gamma-crystallin mRNAs and suggest (but do not establish) the existence of a closely related family of gamma-crystallin genes.

Amino Acid Sequence↗
PubMed1981

Rapid removal of acetimidoyl groups from proteins and peptides. Applications to primary structure determination.

Methylamine buffers can be used for the rapid quantitative removal of acetimidoyl groups from proteins and peptides modified by treatment with ethyl or methyl acetimidate. The half-life for displacement of acetimidoyl groups from fully amidinated proteins incubated in 3.44 M-methylamine/HCl buffer at pH 11.5 and 25 degrees C was approx. 26 min; this half life is 29 times less than that observed in ammonia/HCl buffer under the same conditions of pH and amine concentration. Incubation of acetimidated proteins with methylamine for 4 h resulted in greater than 95% removal of acetimidoyl groups. No deleterious effects on primary structure were detected by amino acid analysis or by automated Edman degradation. Reversible amidination of lysine residues, in conjunction with tryptic digestion, has been successfully applied to the determination of the amino acid sequence of an acetimidated mouse immunoglobulin heavy chain peptide. The regeneration of amino groups in amidinated proteins and peptides by methylaminolysis makes amidination a valuable alternative to citraconoylation and maleoylation in structural studies.

Amino Acid Sequence↗
PubMed1981

Four further examples of anti-Inb detected during pregnancy.

Four further examples of anti-Inb are described. All four were detected during pregnancy in patients from the Asian immigrant community living in the North of England. Anti-Inb, even when an IgG antibody, is unlikely to cause haemolytic disease of the newborn as it seems unable to cross the placenta. Observations are also made on the frequency of the Ina and Inb antigens in both the native English and Asian immigrant populations.

Asia↗