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Biomedical subjects

M Sutherland

Publications and source records attributed to M Sutherland.

At least 37 records · Page 2Linked to original sources
PubMed1994

The protein tyrosine kinase ZAP-70 can associate with the SH2 domain of proto-Vav.

Stimulation of the T cell antigen receptor (TCR) leads to tyrosine phosphorylation of a number of cellular proteins, including the vav proto-oncogene product. We now report the detection of several phosphotyrosine proteins (80, 74, and 70 kDa) from TCR-stimulated T cells that bind to the Src homology 2 (SH2) domain of proto-Vav (Vav-SH2) and co-immunoprecipitate with the proto-Vav product. Their binding to Vav-SH2 differs from that observed with SH2 domains from other proteins. None of the Vav-SH2-associated phosphoproteins bind to either of the Src homology 3 (SH3) domains of proto-Vav or to mutant Vav-SH2 proteins. The association of the phosphoproteins with Vav-SH2 requires induction of tyrosine phosphorylation of cellular proteins since proteins from lysates of herbimycin A-treated TCR-activated T cells fail to associate with Vav-SH2. Among the proteins from T cells that co-immunoprecipitate with the proto-Vav product and bind to its SH2 domain, specific antibodies identified the 70-kDa tyrosine phosphoprotein as ZAP-70, a protein tyrosine kinase (PTK) involved in TCR signal transduction. Binding of this PTK to Vav-SH2 is inhibited by a ZAP-70-specific synthetic tyrosine phosphopeptide. We suggest that ZAP-70 may function as a PTK for proto-Vav.

3T3 Cells↗
PubMed1994

Cloning, sequence and in vitro transcription/translation analysis of a 3.2-kb EcoRI-HindIII fragment of Leuconostoc oenos bacteriophage L10.

A 3.2-kb EcoRI-HindIII DNA fragment of Leuconostoc oenos bacteriophage L10 was cloned and sequenced. Computer-assisted analysis of the sequence identified eleven possible open reading frames (ORFs) that were all on the same strand. In vitro transcription/translation analysis of the full-length DNA fragment yielded five prominent proteins that were correlated with ORFs by their sizes and expression from deleted clones. Only those ORFs containing recognizable Shine-Dalgarno sequences coded for proteins. Neither the nucleotide sequence, nor deduced amino-acid sequences showed significant homology with other known sequences.

Amino Acid Sequence↗
PubMed1993

Effects of interleukin-4 and interferon-gamma on the secretion of IgG4 from human peripheral blood mononuclear cells.

Whereas IgE antibodies are linked with allergy, IgG4 antibodies may reflect the state of immunity and protection against a particular antigen. It has been shown that interleukin (IL)-4 is required for induction of IgE synthesis. In order to elucidate the role of IL-4 in the production of IgG4 and to compare IgG4 and IgE regulatory processes, we quantified these immunoglobulin isotypes after in vitro culture of peripheral blood mononuclear cells (PBMC) in the presence of IL-4. The production of IgG4 was increased by IL-4 under the same conditions which are optimal for IgE production but not among PBMC from all donors, depending on the magnitude of spontaneous IgG4 secretion: IL-4 was effective only when the spontaneous secretion of IgG4 was < 7% of the total IgG secretion; it had no effect when spontaneous IgG4 production was > 7% of total IgG. The IL-4-induced IgE response was consistently obtained when IgG4 was < 7% of total IgG but was markedly diminished or absent when IgG4 was > 7% of total IgG. If Staphylococcus aureus strain Cowan 1 (SAC) was present during the 48-h preincubation step, spontaneous IgG4 production was increased, but the stimulatory effect of this mitogen on immunoglobulin production, including IgG4, was markedly blocked by the addition of IL-4. In contrast, IL-4-induced IgE synthesis was strongly blocked by the presence of SAC. Finally, secretion of IgG4 (spontaneous and IL-4-induced) was suppressed among cells from most donors by interferon-gamma (IFN-gamma).(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1989

Absence of a bleeding tendency in severe acquired von Willebrand's disease. The role of platelet von Willebrand factor in maintaining normal hemostasis.

A 67-year-old male with a prolonged activated partial thromboplastin time (APTT) of 43 seconds (normal, 25-40 seconds) was found to have laboratory features of von Willebrand's disease and IgA myeloma but had a normal bleeding time and no bleeding tendency. Plasma Factor VIII coagulant activity (F.VIII:C) was 80 U/L (0.08 U/mL), Factor VIII antigen (F.VIII:Ag) 70 U/L (0.07 U/mL), and von Willebrand's factor antigen (vWF:Ag) 50 U/L (0.05 U/mL) and ristocetin cofactor (vWF:RiCoF) 10 U/L (0.10 U/mL). The platelet vWF:Ag level was normal, whereas both platelet lysate and plasma vWF high molecular weight multimers were decreased. Patient plasma had no inhibitory effect on either F.VIII:C or vWF:RiCoF. However, when patient plasma was incubated with normal plasma, crossed immunoelectrophoresis for vWF:Ag demonstrated the presence of immune complexes. Infusion of 1-desamino-8-D-arginine vasopressin led to a transient correction of the plasma vWF:Ag multimer pattern. The survival of all components of vWF/F.VIII was decreased, as also occurred after cryoprecipitate. The levels of plasma F.VIII/vWF increased as the IgA values decreased after chemotherapy, whereas the platelet high molecular weight multimers remained decreased. The data suggest that the plasma vWF/F.VIII deficiency results from complexing of the IgA myeloma protein with vWF, resulting in premature clearance of the vWF/F.VIII complex. The absence of clinical bleeding likely results from the combination of a normal platelet vWF:Ag level and persistence of intermediate molecular weight vWF multimers.

Acute Disease↗
PubMed1989

A double-blind comparison of conventional and controlled-release carbamazepine in healthy subjects.

1. Eight healthy subjects took part in a balanced, double-blind, crossover comparison of conventional carbamazepine (Tegretol, Ciba-Geigy Ltd, CBZ-C) and a novel controlled-release formulation (Tegretol CR Divitabs, Ciba-Geigy Ltd; CBZ-CR). An initial single dose of either preparation was followed 1 week later by a 2 week course of 200 mg twice daily. 2. Following the single dose, CBZ-CR produced a concentration plateau from 6-56 h at 50-60% of the CBZ-CR peak. 3. After 2 weeks' treatment, CBZ daytime levels measured as area under the concentration-time curve over a dosage interval were 7% lower with CBZ-CR, but this difference was not statistically significant. 4. CBZ-CR showed less diurnal fluctuation (12%) of CBZ than CBZ-C (24%; P less than 0.025) with less rapid changes in concentration (P less than 0.02). 5. Diurnal fluctuation of free CBZ and of CBZ 10,11 epoxide, the active metabolite, did not differ significantly between the two preparations. 6. Auto-induction of CBZ metabolism resulted from the administration of both formulations. The mean elimination half-life was 23 h (CBZ-C) and 25 h (CBZ-CR) after dose 29 compared with a base-line value of 37 h (both P less than 0.02). Antipyrine metabolism was also induced to a similar extent in both legs of the study (P less than 0.01). 7. No significant alteration in psychomotor function was demonstrated with either preparation. 8. CBZ-CR fulfils the criteria for a controlled-release preparation with comparable apparent bioavailability to CBZ-C. Further pharmacokinetic and, more importantly, pharmacodynamic studies are required in epileptic patients to confirm a clinical advantage over the currently available formulation.

Adult↗
PubMed1988

The effect of breakfast on social behavior and brain amine metabolism in vervet monkeys.

Two groups of vervet monkeys were fed, on alternate days, either before or after a morning observation period. This enabled us to determine changes in behavior when the animals were fed a nutritionally balanced breakfast of monkey chow. Feeding did not alter the proportion of behaviors that were social or non-social, but had a marked effect on individual behaviors. Feeding increased active behaviors among the adult animals except for the vervets who were lowest in the social hierarchy in each cage. For some of the individual behaviors that were altered by feeding, the changes were most marked early on in the observation period, when the animals were still feeding. Other behavioral changes were seen only later in the observation period, a time course consistent with a food-mediated change in brain biochemistry. A parallel biochemical experiment showed that feeding decreased the levels of tryptophan and 5-hydroxyindoleacetic acid in the CSF. Our data indicate that feeding can influence both brain biochemistry and behavior. The behavioral changes may be influenced by social and psychological factors as well as changes in brain biochemistry.

Aging↗
PubMed1987

Recognition of a purified Mr-40,000 organ-specific immunogen of human lung cancer by class II-restricted T-cells.

An Mr-40,000 polypeptide (p40) was purified from a lung cancer cell line on the basis of its antigenicity with leukocytes from lung cancer patients in an in vitro immunological assay of leukocyte adherence inhibition. Here, the cells and mechanism responsible for recognizing the purified p40 organ-specific cancer neoantigen (OSN) were studied. Buffy coat leukocytes from lung cancer patients showed a bell-shaped dose response with a peak response at 0.75 micrograms/assay. Mononuclear cells showed a similar response pattern, whereas pure T-cells were unreactive. Monoclonal antibodies (MAbs) to T-cell differentiation antigens T3 and T4 inhibited the response in a dose-dependent fashion, whereas anti-T8 had no effect, indicating T helper cells and their T3-antigen receptor complex recognized the antigen. MAbs to class II major histocompatibility complex (MHC) antigens also inhibited the response, whereas MAbs to class I MHC had no effect, indicating an important role for class II MHC antigens of monocytes. None of the MAbs inhibited the response to OSN on membrane fragments, which is mediated by antibody-dependent monocytes. Trypsin- or cyanogen bromide-cleaved p40 OSN triggered a response at the same concentrations as the intact molecule. The p40 OSN incubated with live leukocytes showed less than 30% proteolytic digestion. The results indicate that class II-restricted T-cells recognize, via their antigen-specific cell surface receptors, contiguous sequences within the immunogenic tumor molecule in the context of the molecule or peptides binding to class II transplantation antigens.

Antibodies, Monoclonal↗
PubMed1986

Identification of a Mr 40,000 polypeptide from colorectal cancer which expresses organ-specific cancer neoantigen activity as determined by leukocyte adherence inhibition.

Human cancers express organ-specific neoantigens (OSNs) that elicit immune responses in the tumor host. Leukocyte adherence inhibition, an in vitro assay that detects the antitumor immunity, was used to monitor the purification of the OSN from serum-free spent medium of tissue-cultured colon cancer cell lines (HCT-15 and SW-620). A monoclonal antibody (anti-p40) directed to a cross-reactive framework determinant of Mr 40,000 (p40) cell surface polypeptide, which was a principal component of the enriched isolate with OSN activity, was used to monitor the purification of p40 by enzyme-linked immunosorbant assay. About 50 liters of spent medium were generated from 20 m2 of cells, collected, concentrated, and then separated by anion exchange, molecular-sieve, and blue-Sepharose affinity chromatography. OSN and p40 activity coisolated. p40 was then purified by monoclonal antibody anti-p40 affinity chromatography. The affinity-purified fraction was enriched for both p40 and leukocyte adherence inhibition activity that was specific for leukocytes from colon cancer patients in blind leukocyte adherence inhibition assays. When affinity-purified p40 from colon and lung cancers was tested blind in a criss-cross fashion with leukocytes from colon and lung cancer patients, the positive responses were to the appropriate p40. The homologous colon cancer p40 molecule showed size and considerable charge microheterogeneity (pI 6.3 to 7.6). Affinity-purified p40 and OSN coisolated on hydrophobic interaction and hydroxylapatite high-pressure liquid chromatography. Note that not all colon cancer OSN activity was bound by the anti-p40 affinity column. However, unbound OSN activity also eluted from hydrophobic interaction high-pressure liquid chromatography at the same time as affinity-purified p40, and residual p40 activity was detected by enzyme-linked immunosorbant assay. The results indicate that a p40 glycoprotein from the cell membrane of colon cancer cells coisolates with fractions having OSN activity. Impurities do not seem to account for the OSN activity. The OSN epitope on the Mr 40,000 molecule is recognized by leukocytes from colon cancer patients and is distinct from the cross-reactive framework determinant recognized by mouse monoclonal antibody anti-p40.

Antibodies, Monoclonal↗
PubMed1985

Purification from a human lung cancer cell line of a water soluble molecule mediating leukocyte adherence inhibition for patients with lung cancer.

Soluble lung tumor activity as determined by LAI2 was enriched by physicochemical methods from chemically - defined spent medium of a lung cancer cell line (NCI-H69). To identify the polypeptide carrying the antigenic determinant, splenic lymphocytes of BALB/c mice were immunized with the enriched isolate and hybridized with mouse plasmacytoma cells. Eight hybrids were cloned successfully and produced MAbs that immunoprecipitated principally a single chain of Mr 40,000 (p40) as well as minor chains of Mr 25,000 (p25) and Mr 13,000 (p13) which were probably degradation products of p40. On 2D gels, p40 was composed of 7 spots with a p1 of 6.3 to 7.6, which was not altered by neuraminidase digestion. Affinity chromatography with MAb anti-p40 absorbed p40 and LAI activity. The bound and recovered fraction was enriched for p40 and LAI activity. Affinity-purified p40 also contained the previously identified p25 and p13 as well as a Mr 32,000 peptide (p32). MAb anti-p40 was directed to a common framework determinant on p40 since MAb anti-p40 bound to cancer cells from other organs. The comparatively lung cancer organ-specific determinant recognized by leukocytes from lung cancer patients was not recognized by the MAb. Affinity-purified p40 triggered LAI for leukocytes from patients with lung cancer but not for leukocytes from control subjects or patients with colon cancer or malignant melanoma in rigorous blind testing. Crossreactivity was observed with leukocytes from patients with breast cancer. LAI activity of affinity-purified p40 seems unlikely to result from an unidentified impurity. Thus a p40 molecule has been purified that is expressed on the membranes of lung cancer cells and triggers immunologically-mediated LAI.

Antibodies, Monoclonal↗
PubMed1984

Ingestion of egg raises plasma low density lipoproteins in free-living subjects.

In addition to their usual diet, 17 lactovegetarian college students consumed 400 kcal of test foods per day containing one extra-large egg for three weeks and similar isocaloric eggless foods for an additional three weeks in a randomised double-blind crossover trial. Ingestion of the egg increased dietary cholesterol from 97 to 418 mg per day. Mean plasma low density lipoprotein (LDL) cholesterol was 12% higher (p = 0.005) and mean plasma apolipoprotein B was 9% higher (p = 0.007) when eggs were being consumed than during the eggless period. Mean plasma high density lipoprotein cholesterol, apolipoproteins A-I and A-II, very low density lipoprotein cholesterol, and total triglycerides did not change significantly. Thus, ingestion of egg seems selectively to raise cholesterol and protein in LDL particles in the plasma of free-living normal people. Plasma LDL may be more sensitive to cholesterol at low intakes than at moderate to high intakes.

Adolescent↗