Gas chromatographic analysis of histamine in mahi-mahi (Coryphaena hippurus)

Several authors have studied histamine using gas chromatography (GC) as a tool for quantitation, but the methods used were not always suitable depending on the kind of food. Problems frequently cited include incomplete histamine elution from the columns and peak tailing. Histamine is of interest because it is the factor common to all cases of scombroid poisoning, it has physiological and biological activity, and it is a chemical indicator of fish quality. In this study a modified GC method was used to quantify histamine in mahi-mahi (Coryphaena hippurus). Mean recovery was 67% for the GC method, compared with 90% for the AOAC fluorometric method. There was a 0.96 correlation of the GC histamine values with those of the AOAC fluorometric method. A temperature program, splitless/split injection, and analyte cleanup were essential for GC properties. Histamine retention time was 8.2 min. The method allowed peak height to be used for quantitation and simultaneous analysis of cadaverine and putrescine.     

HPLC method for analysis of free amino acids in fish using o-phthaldialdehyde precolumn derivatization

Precolumn derivatization applying o-phthaldialdehyde (OPA) was used to analyze free lysine, histidine, and ornithine, precursors of the respective biogenic amines cadaverine, histamine, and putrescine, which are considered indicators of fish quality and safety. This method uses 75% methanol to eliminate the use of strong acids as the extraction solution. Each analysis took 35 min, was reproducible, and allowed separation of primary amino acids in fish samples. A binary solvent delivery system coupled with a fluorescence detector and an Ultrasphere ODS column were utilized for HPLC separation. Linearity of the calibration curves was very good (r(2) = 0.99) for the amino acids of interest. Minimum concentrations of detection were 40 pmol/mL for histidine and lysine and 70 pmol/mL for ornithine. Average recoveries were 72% for lysine, 93% for histidine, and 98% for ornithine. This method used solvent gradient elution to study the levels of these analytes in mahi-mahi, bigeye tuna, and flounder.     

Field comparison of the interferon-gamma assay and the intradermal tuberculin test for the diagnosis of bovine tuberculosis

An extensive field comparison of the gamma interferon (IFN-gamma) assay and the single intradermal tuberculin test for the diagnosis of bovine tuberculosis was conducted in Australia. The specificity of the IFN-gamma assay was determined by testing more than 6000 cattle from tuberculosis-free herds and varied from 96.2% to 98.1%, depending on the cut-off point chosen to define a positive reactor. For the sensitivity trial, cattle from herds being de-populated because of bovine tuberculosis were examined with both assays. The sensitivity of the IFN-gamma assay was shown to be significantly higher than the single intradermal tuberculin test and varied from 76.8% to 93.6% depending on the method of interpretation. A maximum overall sensitivity of 95.2% was obtained by testing with the IFN-gamma and the tuberculin test in parallel. The superior sensitivity of the IFN-gamma assay and the ability to adjust the sensitivity of the system depending on the task involved, will provide the Australian Tuberculosis Eradication Campaign with a valuable additional test to enable it to accomplish its goals.     

Co-occurrence of autoimmune thyroid disease in a multiple sclerosis cohort

Background

Multiple sclerosis (MS), Hashimoto's disease and Graves' disease are autoimmune diseases that may share similar pathogenic mechanisms. The co-occurrence rates and demographic characteristics of Graves' disease and Hashimoto's disease (HT) in our MS population are compared with the general population.

Methods

The prevalence of thyroid disease in our MS patients was determined by chart review and survey. Previous diagnosis of thyroid disease, age at diagnosis, treatment used, and about the use of disease modifying medications used to treat their MS were asked. Chart reviews were used to estimate the population prevalence of Graves' disease and Hashimoto's disease and to estimate the demographics of patients with thyroid disease.

Results

A significant co-occurrence of Graves' disease with MS (p = 0.002), and a non-significant co-occurrence of Hashimoto's disease were noted (p = 0.097). No difference in the age of onset or gender of thyroid disease in MS patients compared to the general population was found.

Conclusion

There is a significant co-occurrence in patients with MS and Graves' disease, and a trend to co-occurrence in patients with MS and Hashimoto's disease. There are no differences in the demographics of patients with thyroid disease in our MS patients compared to the general population.

     

Up‐Regulation of Insulin‐Like Growth Factor I and Uteroglobin in In Vivo‐Developed Parthenogenetic Embryos

Parthenote embryos are being considered as an alternative source of embryonic stem cells. However, as there is still a dearth of knowledge of this kind of embryos, a better understanding of their biology is needed for their application. In this work, we studied the differences and similarities between parthenotes and normal embryos at the blastocyst stage in vivo developed. We analysed the expression of factor OCT‐4, vascular endothelial growth factor (VEGF), insulin‐like growth factor I (IGF‐I) and uteroglobin (UG) by real‐time PCR. To do so, oocytes were recovered and after activation procedure were transferred by ventral middle laparoscopy to receptive does to undergo completely in vivo development. Does were slaughtered 6 days post‐ovulation induction, and parthenote and normal embryos were recovered for mRNA expression analysis. Our results reported that parthenotes and normal embryos showed similar mRNA expression for OCT‐4 and VEGF. However, IGF‐I and UG showed to be over‐expressed in parthenote embryos. Thus, our study highlights that despite the in vivo development of parthenotes, they still seem to have an altered expression and, therefore, to be different to normal embryos. The altered expression pattern of parthenote embryos suggests that these embryos should be studied carefully before future application.