PubMed · 4895202
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H Trinkler. 1968. [On working with formaldehyde].. https://pubmed.ncbi.nlm.nih.gov/4895202/
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BACKGROUND: Involvement of the lateral resection margin (LRM) has been shown to be a reliable predictor of local recurrence of rectal cancer. Accurate determination of the LRM status is crucial in selecting patients for postoperative radiotherapy. However, variability in processing factors may affect the measurement of the LRM. AIM: To investigate how formalin fixation and laboratory processing affects the measurement of the LRM. METHODS: For this study, rectal cancer specimens (n = 9) were fixed in formalin for 4 days and then sectioned transversally, and one half of the specimen was sent for processing. The effacing tumours were placed back in formalin for another 3 days. At day 7, the effacing tumour block (mirror image) was sent for processing. The longest and the shortest perpendicular resection margins for each of the day 4 and day 7 specimens were measured. In a second experiment, control tissue (colon; n = 40), length 10 (0.05) mm, was also processed from a normal sigmoid colon. Specimens were retained in formalin for 24 h (n = 12), 48 h (n = 12), 72 h (n = 9) and 96 h (n = 7). The degree of tissue shrinkage was then recorded. Variations in the recorded LRM and length of colonic tissue are presented as a median (interquartile range) and data were compared using analysis of variance. RESULTS: In the cases of rectal cancer, the variation in measured LRM between day 4 and day 7 specimens was 3.2 (1.5-5) mm. In 30 of the 37 comparisons, the day 7 LRM increased in length, whereas in the remaining 7 it decreased. In the second experiment, control tissue of the original length 10 (0.05) mm increased in length to 10.9 (8.9-13.0) mm, p<0.01. CONCLUSION: These results suggest that the fixation period/laboratory processes result in measurable differences in the reported LRM. This degree of variation has implications for the reliable reporting of the LRM, predicting local recurrence rates and planning subsequent adjuvant radiotherapy.
In this study, advanced oxidation processes (AOPs) utilizing the combinations of UV/H(2)O(2), Fenton, photo-Fenton and the combination of Fenton/photo-Fenton reactions were investigated in lab-scale experiments for the degradation of formaline wastewater. The studied toxic chemicals were formaldehyde and methanol in mixture solution, so-called formalin, which is the embalming agent in mortuaries. The experimental results showed that the photo-Fenton process was the most effective treatment process among the studied AOPs. Pseudo-first-order degradation rate constants of formaldehyde and methanol were obtained from batch experimental data. In the combination of Fenton/photo-Fenton reactions, the results show that applying UV light at an early stage of the reaction might not be necessary for a speedy oxidation reaction of the Fenton process. With Fenton and photo-Fenton processes, mineralization of formaline wastewater can be achieved, as no residual TOC is detected in the effluent after the reaction period. It is suggested that Fenton and photo-Fenton processes are viable techniques for the formaline wastewater treatment as they were able to provide high degradation of formaldehyde and methanol with relatively low toxicity of the by-products in the effluent.
Orcokinins are a family of myotropic neuropeptides widely present in various decapod crustaceans and insect species. The majority of the orcokinins identified to date share a conserved sequence of NFDEIDR at their N-termini. Electrospray ionization quadrupole time-of-flight tandem mass spectrometric (ESI-QTOF-MS/MS) analysis of doubly charged orcokinin precursor ions reveals the presence of a y(n - 1) + 10 peak, which is more intense than that for the y(n - 1) ion. To elucidate the identity of this novel fragment ion and understand the mechanism underlying this fragmentation, we employed a combined approach involving the use of isotopic N-terminal dimethylation, methyl esterification, and isotope-encoded NFDEIDR. Comparison of the fragmentation patterns of these chemically modified orcokinin analogs allowed the determination of the structure of the y(n - 1) + 10 ion as y(n - 1) + CO--H2O. The yx + CO--H2O ions, along with the yx + CO and yx + CO--NH3 ions, are also present in the MS/MS spectra of NFDEIDR and several other peptides. Additionally, we report two other unusual fragmentation ions in the MS/MS spectra of N-terminal dimethyl NFDEIDR (2+), which yields the novel fragment ions of the y(n - 1) + 38 ion and the [M+2H-59]2+ ion. These two ion series involve the neutral loss of the asparagine side chain. The same sets of ions are also present in other peptides with dimethyl-modified asparagines at the N-terminus. The competition between the side-chain loss and loss of dimethylamine is described. The loss of the side chain of N-terminal dimethyl Asp1 is reported as well. We also report for the first time the neutral loss of ammonia from the N-terminal amino group of Asn1 and the loss of CO2 from the side chain of aspartic acid.