Construction of a multiple mucin tandem repeat with a mutation in the tumor-specific epitope by a solid-phase gene assembly protocol.
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Amino Acid Sequence↗
Biomedical subjects
S E Wright
Publications and source records attributed to S E Wright.
Bilayer stabilization of phosphatidylethanolamine by N-biotinylphosphatidylethanolamine.
We have examined the ability of biotinylated phosphatidylethanolamine and similar lipids to stabilize the bilayer phase of polymorphic dioleoylphosphatidylethanolamine (DOPE). Sonicated lipid mixtures were characterized in terms of their aggregation state, size and ability to encapsulate and retain the fluorescent dye, calcein. Titration of DOPE with N-biotinyl-PE indicated that stable liposomes could be produced by sonication of DOPE based dispersions containing N-biotinyl-PE at concentrations greater than 8 mol%. These liposomes were relatively small, could efficiently encapsulate calcein, and showed minimal leakage upon prolonged storage at 4 degrees C. Maleimido-4-(p-phenylbutyrate)-PE (MPB-PE) was equally effective at stabilizing the bilayer phase of DOPE whereas N-dinitrophenyl-PE and N-(dinitrophenyl-caproyl)-PE were relatively poor stabilizers, requiring at least 15 mol% for stabilization at pH 7.4. Differential scanning calorimetry of dielaidoylphosphatidylethanolamine (DEPE)/N-biotinyl-PE mixtures indicated that stabilizer concentrations as low as 2 mol% could abolish the L alpha/HII phase transition of DEPE.
Biotin↗
Avian retroviral recombinant expressing foreign envelope delays tumour formation of ASV-A-induced sarcoma.
An avian recombinant retrovirus expressing subgroup A envelope glycoprotein antigenicity, RAV-0-A1, significantly delayed sarcoma induction in chickens after challenge with ASV-A. When tumours were formed, significantly smaller tumours resulted. The mechanism of protection does not appear to be interference mediated, since virus was not detected in the chickens. Protection was correlated with both neutralizing and complement-dependent cytotoxic antibodies (CDCA).
Aging↗
Comparative study of the antigenic composition of oocyst isolates of Cryptosporidium parvum from different hosts.
An investigation was made of the antigenic composition of oocyst isolates of Cryptosporidium parvum by immunoblotting using rabbit polyclonal or murine monoclonal antibodies (MoAbs) developed against this parasite. Using the polyclonal antibodies in blots, a common antigenic profile was obtained from a number of human oocyst isolates from AIDS patients and immunocompetent children in the UK and Portugal. Antigenic differences were observed, however, between a human isolate from Turkey and these other human isolates. The antigenic profiles of oocyst isolates from deer and cattle were similar, but the profiles of the animal and human isolates differed to some extent. Two MoAbs which, in immunofluorescence microscopy, reacted with the surface of the C. parvum sporozoite were also used in blots. A major antigen(s) from 9 of 11 human oocyst isolates recognized by these MoAbs had a molecular weight of 47 kD, but the sizes of the corresponding antigens of the remaining 2 human isolates, one from Turkey (same as above) and one from the UK, were 45.5 and 51 kD, respectively. The equivalent antigen(s) from 4 bovine and 4 ovine isolates was 48 kD. One of the MoAbs failed to react in blots with 2 of the isolates, 1 human and 1 bovine.
Acquired Immunodeficiency Syndrome↗
Positive pressure mechanical ventilation augments left ventricular function in acute mitral regurgitation.
Although inconclusively established, positive pressure ventilation may augment cardiac function in congestive cardiomyopathies. We report a patient with acute mitral regurgitation who experienced enhanced myocardial performance and resolution of large pulmonary artery v waves during mechanical ventilation. This observation supports the existence of a cardiac booster effect from positive pressure ventilation.
Acute Disease↗
Prevalence of human T-lymphotropic virus in civilian applicants for the United States Armed Forces.
BACKGROUND: The wide range in human T-lymphotropic virus (HTLV) seroprevalences reported worldwide has made estimates of seroprevalence difficult in unique populations. In this study, the seropositivity of young adult civilian applicants for the US Armed Forces was determined. METHODS: Serum samples from nine geographic regions were screened by an Enzyme-Linked Immunosorbent Assay (ELISA), and repeatedly reactive samples were further tested by Western blot and radioimmunoprecipitation. Specimens were scored as positive when antibody to gag (p24) and env (gp46 or gp68) were detected. RESULTS: Of the 43,750 samples analyzed, 18 were positive for HTLV antibodies. Ten (55%) were from males and eight (45%) were from females. Nine (90%) of the males and seven (87.5%) of the females were Black. Twelve of the positive samples (66.6%) were from the New York City region, which represented only 18.8% of the sample population. CONCLUSIONS: The overall HTLV seroprevalence of civilian applicants for the US Armed forces was 0.41 per 1000. This was higher than the seroprevalence reported for volunteer blood donors.
Adolescent↗
Partitioning of teniposide into membranes and the role of lipid composition.
We have examined the partitioning behavior of the anticancer agent teniposide (VM-26) into multilamellar vesicles composed of various phospholipid species. Partitioning was found to be sensitive to the composition of the liposomal membrane since changes in the head group or acyl chain constituents could dramatically alter the affinity of the drug for the bilayer. [3H]VM-26 partitioned most readily into 1,2-monounsaturated species of phosphatidylcholine (PC) with a molar partition coefficient (Kp) of 4290 for dioleoyl-PC at 37 degrees C. Inclusion of additional phospholipids having a different head group reduced partitioning in the order cardiolipin greater than phosphatidylglycerol greater than phosphatidylserine greater than phosphatidylethanolamine. The Kp for dioleoyl-PC with 33 mol% cardiolipin was reduced to 1370. Partitioning into completely saturated species of PC was much less than that for unsaturated species and was inversely proportional to the hydrocarbon chain length at temperatures either above or below the chain melting temperature. The Kp for fluid phase dimyristoyl-PC was 2300. Partitioning into dimyristoyl-PC or dioleoyl-PC at 37 degrees C (fluid) or dipalmitoyl-PC at 25 degrees C (gel) was reduced by the addition of 5-30 mol% cholesterol in proportion to its bilayer concentration. Etoposide (VP-16) at concentrations up to 10 mol% did not compete with [3H]VM-26 for association with dioleoyl-PC. Addition of calf serum or serum albumin could significantly reduce the association of [3H]VM-26 with the liposomes.
Etoposide↗
Effects of the lipophilic anticancer drug teniposide (VM-26) on membrane transport.
The epipodophyllotoxin glucopyranosides have previously been shown to interact with membrane lipids and to alter the activity of several lipid-embedded membrane proteins. To determine if these agents are acting as general membrane perturbants, we have further examined their effects on membrane processes in Ehrlich ascites tumor cells. [3H]VM-26 and [3H]VP-16 were taken up rapidly and concentrated within the cells in proportion to their lipophilicity. Neither agent was found to have any significant effect on the influx of L-[3H]leucine or alpha-[3H]aminoisobutyric acid. Likewise, these drugs had no significant effects on the hexose transporter. The nucleoside transporter, which is structurally and functionally similar to the hexose transporter, was dramatically affected, however. VM-26 was a non-competitive inhibitor of equilibrium-exchange influx of cytosine arabinoside in Ehrlich cells with a Ki of 15 microM. Equilibrium-exchange influx increased with temperature in control cells (Q10 = 2) but not in VM-26-treated cells; thus, VM-26 was a more potent inhibitor at higher temperatures. VM-26 also significantly reduced zero-trans influx in Ehrlich, P388, L5178Y, and ML-1 cells, and these effects were immediate in onset. VM-26 inhibited high-affinity binding of the nucleoside transport inhibitor nitrobenzylmercaptopurine riboside (NBMPR), but VM-26 enhanced non-specific NBMPR binding to Ehrlich cells. The apparent specificity of the epipodophyllotoxins for the nucleoside transporter is discussed.
Amino Acids↗
Region coding for subgroup specificity of envelope of avian retroviruses does not determine lymphomagenicity.
The purpose of this study was to test whether the region coding for subgroup envelope specificity was a determinant of oncogenic potential. An avian retrovirus recombinant was constructed to contain the envelope gene (env) determinant for subgroup A of an avian RNA tumor virus in one of the non-oncogenic, endogenous avian retroviruses, RAV-0. The results show that such a recombinant virus does not induce lymphoma when injected into susceptible, newborn chicks. Thus, it is concluded that the envelope determinant for subgroup of avian RNA tumor viruses does not determine malignant potential.
Animals↗
Oligosaccharide chains of avian RNA tumor virus glycoproteins contain heterogeneous oligomannosyl cores.
Chicken embryo fibroblasts (C/E phenotype) infected with subgroups B and C of the Prague strain of Rous sarcoma virus were radiolabeled with either [6-(3)H]-glucosamine or [2-(3)H]mannose, and virus was purified from the growth medium. The large envelope glycoprotein, gp85, was the only major radiolabeled component of purified virus. Pronase-digested glycopeptides from purified virus were analyzed by a combination of (i) gel filtration with columns of Sephadex G15/G50 and Bio-Gel P4 and (ii) enzymatic digestion of the oligosaccharide chains with specific exoglycosidases and endo-beta-N-acetylglucosaminidases. The rather broad molecular weight distribution (approximately 2,000 to 4,000) for glycopeptides in these studies and previous studies in other laboratories was shown to represent actual heterogeneity in the carbohydrate moieties: (i) the glycopeptides contained both mannose-rich, neutral chains and complex, acidic chains with terminal sialic acid; and (ii) both classes of asparagine-linked carbohydrate structures exhibited heterogeneity in the size of the oligomannosyl core (a mixture of approximately 5 to 9 mannose units for the neutral structures, and 3 or 5 mannose units for the acidic structures). With the [2-(3)H]mannose-labeled glycopeptides from Rous sarcoma virus, Prague strain subgroup C, most of the oligosaccharide chains were high-molecular-weight, acidic structures, with similar numbers of 3-mannose and 5-mannose core structures.
Acetylglucosaminidase↗
Experience with second marrow transplants.
This report summarizes the experience with 25 patients who received a second marrow transplant. The marrow donor for the first transplant was an identical twin in four cases and a sibling matched at the major histocompatibility complex in 21 instances. The donor for the second transplant was the same as the first except for three patients whose second donor was another matched sibling. Nine patients with aplastic anemia rejected their first graft. Four of these patients were prepared for the second graft with a regimen of procarbazine and antithymocyte globulin (ATG) followed by cyclophosphamide or total body irradiation and were successfully regrafted. One rejected the second graft, two died of septicemia and one is alive and well 10 months after the second graft. Twelve patients with hematologic malignancy had a recurrence of disease after the first transplant. Despite preparation for the second graft with a variety of intensive chemotherapeutic regimens, the five patients who did not succumb to infection showed an early recurrence of disease. Four patients with hematologic malignancy had a failure of the first graft for unknown reasons, possibly related to the administration of ATG or methotrexate. One patient prepared for the second graft with procarbazine and ATG showed evidence of engraftment but died of infection. Two out of three patients given no additional preparation were successfully grafted. One died of recurrent central nervous system leukemia after 18 months and one is alive and well 26 months after the second graft.
Anemia, Aplastic↗
Studies of the interrelationship of chicken leukosis virus and host cell genomes by RNA-DNA hybridzation.
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Animals↗