Immunophenotyping of human HT29 colon cancer cell primary tumours and their metastases in severe combined immunodeficient mice

The immunophenotype of HT29 human colon cancer cells implanted into severe combined immunodeficient mice was assessed in primary tumours and their metastases in the lungs using an indirect immunohistochemical method. After primary tumours were surgically removed, the metastases were given time to develop, thus paralleling the clinical situation. While vimentin was negative in both primary and secondary tumours, E-cadherin was present as membrane-bound labelling in the primary tumours only. Whereas the markers p53, MIB1, PCNA and CEA were consistently positive in both primary and metastatic tumours, CD44 variant 6 and CA125 were negative in metastases but positive in the primary tumours. There was a significant increase in the percentage of cells labelled for p53 in the primary tumours compared with the metastases. For the proliferation markers, there was no significant difference in labelling between primary tumours and metastases for MIB1. Of the cytokeratins examined, CK 20 gave the strongest and most consistent reaction in both primary and secondary tumours. The results indicate that, for certain immunohistochemical markers, results are the same in both primary tumours and metastases. Hence, in these cases, antigens that are expressed on the primary tumour as well as on the metastases can serve as target molecules for immunologically based forms of treatment of metastases. This revised version was published online in November 2006 with corrections to the Cover Date.     

Novel bioemulsifiers from microorganisms for use in foods

The main objective of this study was to test a range of microorganisms for production of extracellular, high molecular weight emulsifiers for potential use in foods. A standard emulsification assay developed specifically for assessing food emulsifiers was used to examine 24 extracellular microbial products from bacteria, yeasts and algae. Of the 24 products tested, nine had emulsification ability that was as good as and eight had emulsifying properties that were better than those of the commonly used food emulsifiers gum arabic and carboxymethylcellulose. The eight good producer organisms included the yeasts Candida utilis, Candida valida, Hansenula anomala, Rhodospiridium diobovatum and Rhodotorula graminis, the red alga Porphiridium cruentum, and the bacteria Klebsiella spp. and Acinetobacter calcoaceticus. Of these, C. utilis was selected for further study due to the excellent emulsification properties of its extracellular products and the food-grade status of the organism. Crude preparations of the bioemulsifier from C. utilis exhibited low viscosity and had a carbohydrate content of over 80%. Preliminary trials showed that the bioemulsifier from this organism had potential for use in salad cream.     

Exclusion of the 13-kDa rapamycin binding protein gene (FKBP2) as a candidate gene for multiple endocrine neoplasia type 1

The MEN1 gene is considered to be a tumour suppressor gene and has been localised to a 1-Mb region of 11q13.1. In this study, we report the physical localisation of the 13-kDa FK506 and rapamycin binding protein gene (FKBP2) to the cosmid marker D11S750, which is located inside the MEN1 region of non-recombination. The product of this gene is involved in signal transduction and is thus a candidate cell growth regulator or tumour suppressor gene. Northern studies have revealed that FKBP2 is expressed in those tissues predisposed to hyperplasia in MEN1; however, single-strand conformation polymorphism analysis and direct sequencing of DNAs from affected members of MEN1 kindreds and sporadic tumour DNAs have been performed and no mutations have been found. These studies exclude FKBP2 as a candidate gene for MEN1.     

A continuous recording technique for the measurement of carbon dioxide, and its application to mitochondrial oxidation and decarboxylation reactions

1. A technique is described for continuously recording the concentration of carbon dioxide in mitochondrial suspensions. 2. The oxidation of palmitoylcarnitine by rat-liver mitochondria inhibits the oxidation of pyruvate and isocitrate, and stimulates the carboxylation of pyruvate. 3. These effects of palmitoylcarnitine oxidation are reversed by the uncoupling agent pentachlorophenol. 4. The effects of palmitoylcarnitine oxidation and pyruvate oxidation on the acylation of mitochondrial coenzyme A and reduction of nicotinamide nucleotides were measured. 5. Control mechanisms are discussed for the interactions between palmitoylcarnitine oxidation and the tricarboxylic acid cycle in rat-liver mitochondria.     

A study of some factors that influence the iodination of ox insulin

1. The influence of carrier iodide, iodine monochloride and pH on the labelling of ox insulin with ¹³¹I by the iodine monochloride method have been studied. 2. The quantitative effect of the iodide in the radioactive iodine preparation was that predicted from a calculation of its specific activity. No other interfering factors were detected in the [¹³¹I]iodide solutions used. 3. Increasing the molar ratio of iodine monochloride to insulin resulted in an increase followed progressively by a decrease in the proportion of ¹³¹I bound, while the total iodine bound increased to an amount characteristic of pH and thereafter remained constant. 4. The influence of pH on the iodination of insulin with iodine monochloride was complex and the pH curve showed two maxima, at pH2·8 and 6·4. At pH2·8 it was not possible to exceed 8 atoms of iodine bound per molecule by increasing the molar ratio of iodine monochloride. Similarly, at pH6·4 the substitution value of 11·5 atoms of iodine per molecule could not be exceeded. 5. Iodinated insulins containing an average of 1·96, 2·74, 6·0 and 7·0 atoms of iodine per molecule fully retained the ability to bind guinea-pig anti-(ox insulin) serum, and the ability to compete with unlabelled insulin for antibody sites only became significantly changed in the most highly substituted preparations and in the presence of large concentrations of unlabelled insulin. 6. The method for the iodination of insulin with 98% incorporation of ¹³¹I by using chloramine-t is described. 7. ¹³¹I-iodinated insulin prepared with graded quantities of chloramine-t in excess of that required for efficient labelling was less efficiently bound by guinea-pig anti-(ox insulin) serum than insulin labelled by the iodine monochloride method.     

Cloning of a genomic fragment carrying the insertion element Cin 1 of Zea mays

Summary Genomic clones from a Northern Flint Line of Zea mays are shown to carry a 700 bp insertion, Cin 1. The Cin 1 insert is not present in the homologous, unique DNA fragment of a midwestern maize line. However, Cin 1 is present in multiple copies in both lines.Restriction enzyme analysis of the cloned DNAs and their corresponding genomic regions suggest that no alterations have occurred during the in vitro cloning procedure.     

The alternate respiratory pathway of Candida albicans

Candida albicans contains a cryptic cyanide and antimycin A insensitive respiratory system. This alternate oxidase was found (i) at all growth rates from =0.05 to 0.26 in a chemostat culture and (ii) in both mycelial and yeast forms of the organism. Neither chloramphenicol nor cycloheximide prevented the expression of the alternate oxidase. Salicyl-hydroxamic acid was a potent inhibitor of the cyanide insensitive respiration. The respiration of mitochondria grown in the presence of antimycin A was not inhibited by cyanide or antimycin A but was inhibited by salicylhydroxamic acid.Abbreviations KCN potassium cyanide - SHAM salicyl hydroxamic acid     

Two methods for producing peripheral anosmia in dogs

Two methods for producing peripheral anosmia in the dog were described. One method involved infusion of 3.5% zinc sulfate into the nasal cavity. An anosmia lasting at least 6 weeks, and, in most cases, for several months, was produced. A second technique, producing short periods of reversible anosmia, was the insertion of a tracheostomy tube with inflatable cuff. Inflation of the cuff prevented the dogs from inhaling air over the olfactory mucosa. Deflation of the cuff restored functional olfaction. The advantages and disadvantages of each technique were discussed.     

Activities of enzymes concerned with pyruvate and oxaloacetate metabolism in the heart and liver of developing sheep.

1. In order to assess whether the potential ability of heart ventricular muscle and liver to metabolise substrates such as alanine, aspartate and lactate varies as the sheep matures and its nutrition changes, the activities of the following enzymes were determined in tissues of lambs obtained at varying intervals between 50 days after conception to 16 weeks after birth and in livers from adult pregnant ewes: lactate dehydrogenase (EC 1.1.1.27), alanine aminotransferase (EC 2.6.1.2), pyruvate kinase (EC 2.7.1.40), pyruvate carboxylase (EC 6.4.1.1), phosphoenolpyruvate carboxykinase (GTP)(EC 4.1.1.32), malate dehydrogenase (EC 1.1.1.37), aspartate aminotransferase (EC 2.6.1.1) and citrate (si)-synthase (EC 4.1.3.7). 2. In the heart a most marked increase in alanine aminotransferase activity was found throughout development. During this period the activities of citrate (si)-synthase, lactate dehydrogenase and pyruvate carboxylase also increased. There were no substantial changes in the activities of aspartate aminotransferase, malate dehydrogenase or pyruvate kinase. Pyruvate kinase activities were five times greater in the heart compared with those found in the liver. No significant activity of phosphoenolpyruvate carboxykinase (GTP) was detected in heart muscle. 3. In the liver the activities of both alanine aminotransferase and aspartate aminotransferase increased immediately following birth although the activity of alanine aminotransferase was lower in livers of pregnant ewes than in any of the lambs. As with alanine aminotransferase the highest activities of lactate dehydrogenase were found during the period of postnatal growth. No marked changes were observed in malate dehydrogenase or citrate (si)-synthase activities during development. A small decline in pyruvate kinase activity occurred whilst the activities of pyruvate carboxylase and phosphoenolpyruvate carboxykinase (GTP) tended to rise during development.