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Biomedical subjects

A Cryer

Publications and source records attributed to A Cryer.

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

Distinct immunoreactivities suggest the existence of potential tissue variants in rat lipoprotein lipase.

Lipoprotein lipases (LPL) isolated from rat cardiac muscle and bovine milk were each used as immunogens to produce polyclonal anti-LPL sera and two anti-LPL monoclonal antibodies. The immunological reactivities of these antibody sources with LPL purified from rat cardiac muscle, lung, adipose tissue, mammary gland and skeletal muscle were compared by an e.l.i.s.a. and by Western blotting. Differences between the immunoreactivities of LPL from the distinct tissue sources were revealed in both systems. A synthetic peptide with a sequence corresponding to the heparin-binding site of LPL (Ser-Arg-Thr-Asn-Thr-Lys-Val-Ser-Arg-Ile-Thr-Gly-Leu) was produced and used as an immunogen. The antiserum produced against the synthetic peptide was found to bind specifically to the region of the heparin-binding site, as determined by use of a competition e.l.i.s.a. In use against the five tissue LPL preparations, this antiserum revealed only minor variations between the tissue sources, compared with the hierarchy of reactivity observed when antibodies raised against the whole molecule were used. In combination with the outcome of previous studies on some of the physical properties of these preparations [Soteriou and Cryer (1993) Int. J. Biochem. 25, 1483-1490], the observations reported here on the distinct immunoreactivities exhibited by LPL prepared from the different tissue sources of a single species indicate the necessity to characterize fully the nature of these differences.

Adipose Tissue↗
PubMed1994

Effect of hosiery on skin temperature in spastic quadriplegia. A preliminary study.

The effect of hosiery on 21 patients with spastic quadriplegia was studied by examining skin temperatures before and after wearing control socks (cotton or cotton/acrylic), compared with the test socks (21% stretch nylon and 80% synthetic hollow-core fiber). The latter are claimed by the manufacturers to provide superior warmth. Other investigations suggest that no material for a given thickness has superior insulation properties. The results of this preliminary study support these investigations, in that no significant difference in skin temperatures was found between the control and test socks when worn by this population.

Foot↗
PubMed1993

Cloning and sequencing of a full length cDNA encoding ovine lipoprotein lipase.

A cDNA clone encoding lipoprotein lipase has been isolated from an ovine adipocyte library. Sequencing of this clone has revealed a single open reading frame encoding a 450 amino acid protein. Comparison with known LPL sequences from other species shows a high degree of conservation in the sequence of the protein and in the 5' untranslated region of the DNA sequence.

Adipose Tissue↗
PubMed1993

Presence and possible significance of immunocytochemically demonstrable metallothionein over-expression in primary invasive ductal carcinoma of the breast.

Metallothioneins (MTs) are ubiquitous low-molecular-weight proteins with a high affinity for heavy metal ions such as zinc, copper and cadmium. MT over-expression has been associated with resistance against anticancer drugs. In the present study we investigated 86 cases (45 cases of tumour category pT1 and 41 of category pT2) of routinely fixed and paraffin-embedded primary breast carcinomas immunohistochemically with a monoclonal antibody to an epitope of MT shared by its I and II isoforms. Immunohistochemically demonstrated MT over-expression was found in the invasive components of 7 of 32 pT1 and 17 of 28 pT2 invasive ductal carcinomas, whereas all 26 invasive lobular carcinomas gave weak or negative results. Fourteen of 17 pT2 and 2 of 7 pT1 invasive ductal carcinomas with MT over-expression developed metastases during follow-up with poor prognostic outcome. In contrast only 3 of 11 pT2 and none of the 25 pT1 cases without MT over-expression had a poor clinical course (P < 0.001). It is concluded that MT over-expression is associated with significantly poor prognosis particularly in pT2 invasive ductal breast carcinomas.

Adult↗
PubMed1993

Purification and characterization of lipoprotein lipase from the white adipose, skeletal muscle, cardiac muscle, mammary gland and lung tissues of the rat.

1. Lipoprotein lipase (LPL) was isolated from five rat tissues: white adipose, skeletal muscle, cardiac muscle, mammary gland and lung. 2. Specific activity of the preparations varied from 75 U/mg for skeletal muscle and 720 U/mg for adipose. 3. The preparations were further analysed using SDS-PAGE and a single component identified. The mol. wt of 61,000 Da of this component was consistent for all five of the tissue sources. 4. Significant differences in the values of the isoelectric points of the enzyme species were revealed. The values varied from 7.23 (SEM 0.022) for cardiac and lung to 7.51 (SEM 0.037) for mammary. 5. Two-dimensional electrophoresis, using isoelectric focusing in the first dimension and SDS-PAGE in the second revealed differences in the patterns of stained material derived from the five tissue sources.

Adipose Tissue↗
PubMed1993

Comparison of the rates of proliferation of adipocyte precursor cells derived from two lines of chicken which differ in their rates of adipose tissue development.

1. Putative adipocyte precursor cells were isolated from the white adipose tissue of young broiler and layer chickens and cultured in vitro. 2. The cells from both sources were shown to have the characteristics of adipocyte precursor cells. On reaching confluence, lipoprotein lipase activity was induced and the cells from both strains accumulated large amounts of lipid in the presence of chicken serum. 3. Measurement of cell number over time in culture and calculation of cell doubling times showed that cells from broilers proliferated at a faster rate than those derived from layer-strain chickens. This was the case whether primary or secondary cell cultures were used. Primary cultures of broiler cells had a doubling time of 22 h versus 39 h for layer cells. 4. The contribution of such a difference in proliferative rate to the differential rate of adipose tissue growth between broiler and layer strains observed in vivo is discussed.

Adipose Tissue↗
PubMed1993

Decreased fat content and increased lean in pigs treated with antibodies to adipocyte plasma membranes.

Antibodies were prepared in sheep against purified plasma membranes from pig adipocytes. Western (immuno) blotting revealed reactions of the antisera with a large number of proteins in adipocyte plasma membranes but remarkably few in plasma membranes from muscle, kidney, liver, lung, brain, spleen, and erythrocytes. This illustrated the high degree of specificity the serum had for adipose tissue. When injected into localized subcutaneous sites such antisera were able to cause considerable adipocyte destruction, which resulted in complete loss of adipose tissue from the site for > or = 14 wk. This cell destruction was probably mediated in part by lymphocytic infiltration. Subcutaneous injections were of limited use because of the localized nature of the effects, but, when treatment was administered intraperitoneally, systemic effects were produced that resulted in a 30% reduction in backfat thickness in the region of the last rib and a 25% reduction in fat content of fore- and hind-loin joints that resulted in a significant increase in the percentage of lean tissue. Total feed intake, live weight gain, hot carcass weights, and dressing percentage were unaffected. These results demonstrate the potential for producing long-term reductions in body fat in pigs by an immunization technique that may also provide the unexpected, potential benefit of increased lean deposition. This suggests that fat deposition per se exerts a restrictive influence on lean carcass development.

Adipose Tissue↗
PubMed1990

The expression of a synthetic rainbow trout metallothionein gene in E. coli.

A synthetic gene for rainbow trout metallothionein was constructed and inserted into a dual origin plasmid where expression was induced by a temperature shift in a proteinase-deficient strain of Escherichia coli. The recombinant protein was purified to homogeneity, and a partial amino acid sequence was determined to confirm its identity. Its immunochemical characteristics were similar to those of native metallothionein from rainbow trout. The amounts of recombinant metallothionein produced were quantified in soluble cell extracts by ELISA. Low concentrations were detected when growth was performed either in L-broth or defined (GMM-II) medium. Supplementation of the medium with zinc or copper had no effect on the amount of metallothionein produced. By contrast, when cadmium was included in either L-broth or GMM-II medium, much higher concentrations of the protein within the cells (approx. 13 micrograms/mg soluble cell protein) were detected. This stabilisation of the protein by metal reconstitution in vivo is considered in relation to the selective uptake/exclusion of metals by the cells and its significance for the scavenging of certain precious or toxic heavy metals is discussed.

Amino Acid Sequence↗
PubMed1990

Immunological distinction between piscine and mammalian metallothioneins.

1. Separate antisera to metallothioneins (MT) from rainbow trout and horse were produced in mice and their reactivity with the respective immunogen was confirmed using an ELISA. 2. The ELISA, used in a competitive mode, revealed that the anti-horse MT serum did not cross-react with trout MT. Reciprocally, the anti-trout MT serum did not show any reactivity with horse MT. 3. The anti-rainbow trout MT serum was shown to cross-react totally with MTs from plaice, flounder, turbot, perch, salmon and pike, but exhibited no reactivity towards MTs from human, mouse, rat, worm or crab. Partial reactivity with the proteins isolated from oyster and mussel was demonstrated. 4. The anti-horse MT serum cross-reacted totally with MTs from human, rat and rabbit but no reactivity was demonstrable when MT from either plaice or worm was tested. 5. The behaviour of apo-, holo- and recombinant rainbow trout MTs, in which the metal content was different, indicated that reactivity with anti-MT antibodies was not dependent on the presence or nature of the metals bound in the protein. 6. The patterns of reactivities were analysed in relation to the known amino acid sequences of MT.

Amino Acid Sequence↗