Photosensitizing effect of protoporphyrin IX in pigmented melanoma of mice

No fluorescence of protoporphyrin IX (PpIX) was measured using a fiber optic probe in pigmented B16F10 melanoma in mice after topical application of 5-aminolevulinic acid methylester (ALA-Me). However, chemical extraction of tissues excised from mice after intratumoral administration of ALA-Me or its parent compound ALA revealed that this tumor had the capability to produce PpIX. Small amounts of endogenous porphyrins, mainly PpIX, were found in the melanoma not treated with these drugs. Topical application of ALA-Me followed by exposure with laser light (633nm) delayed the growth of the tumors slightly. Light alone also had a significant effect on the tumor growth.     

The influence of light and darkness on cutaneous fluorescence in mice.

The present work was carried out to investigate the role of light and darkness on the endogenous biosynthesis of porphyrins in mammalian skin (hairless BALB/c mouse) in vivo. In the skin of mice that were constantly kept in darkness (DD), increased endogenous porphyrin fluorescence was observed, which mainly originated from protoporphyrin IX (PpIX). No significant increase in the porphyrin levels was observed in mice that were kept under a normal day-night cycle (LD 12:12 h). The presence of cutaneous PpIX together with ambient light may comprise a photosensitizing mechanism by which PpIX may be a photomessenger between ambient light and internal rhythms.     

The cluster-tray method for rapid measurement of solute fluxes in adherent cultured cells

The use of an inexpensive and simple modification of Costar 24-well cluster trays is described in a rapid and reproducible method for measuring substrate fluxes in adherent cultured eukaryotic cells.     

Biofuel cell based on direct bioelectrocatalysis

A biofuel cell, consisting of two 3mm diameter carbon rod electrodes and operating at ambient temperature in aqueous solution, pH 6, is described. Biofuel cell based on enzymes able to exchange directly electrons with carbon electrodes was constructed and characterized. Anode of the biofuel cell was based on immobilized Quino-hemoprotein alcohol dehydrogenase from Gluconobacter sp. 33 (QH-ADH), cathode on co-immobilized glucose oxidase from Aspergilus niger (GO(x)) and microperoxidase 8 from the horse heart (MP-8) acting in the consecutive mode. Two enzymes GO(x) and MP-8 applied in the design of biofuel cell cathode were acting in consecutive mode and by hydrogen peroxide oxidized MP-8 was directly accepting electrons from carbon rod electrode. If ethanol was applied as an energy source the maximal open circuit potential of the biofuel cell was -125 mV. If glucose was applied as energy source the open circuit potential of the cell was +145 mV. The maximal open circuit potential (270 mV) was achieved in the presence of extent concentration (over 2 mM) of both substrates (ethanol and glucose). Operational half-life period (tau(1/2)) of the biofuel cell was found to be 2.5 days.     

Determination of allele frequency in pooled DNA: comparison of three PCR-based methods

Determination of allele frequency in pooled DNA samples is a powerful and efficient tool for large-scale association studies. In this study, we tested and compared three PCR-based methods for accuracy, reproducibility, cost, and convenience. The methods compared were: (i) real-time PCR with allele-specific primers, (ii) real-time PCR with allele-specific TaqMan probes, and (iii) quantitative sequencing. Allele frequencies of three single nucleotide polymorphisms in three different genes were estimated from pooled DNA. The pools were made of genomic DNA samples from 96 cases with basal cell carcinoma of the skin and 96 healthy controls with known genotypes. In this study, the allele frequency estimation made by real-time PCR with allele-specific primers had the smallest median deviation (MD) from the real allele frequency with 1.12% (absolute percentage points) and was also the cheapest method. However; this method required the most time for optimization and showed the highest variation between replicates (SD = 6.47%). Quantitative sequencing, the simplest method, was found to have intermediate accuracies (MD = 1.44%, SD = 4.2%). Real-time PCR with TaqMan probes, a convenient but very expensive method, had an MD of 1.47% and the lowest variation between replicates (SD = 3.18%).     

Basal cell carcinoma and variants in genes coding for immune response, DNA repair, folate and iron metabolism

Basal cell carcinoma (BCC) is one of the most common neoplasms in the world and its incidence has been increasing worldwide in recent years. BCCs are caused by an interplay between genetic and environment factors. We conducted a case-control association study in BCC patients and controls from Sweden and Finland. Fifteen single nucleotide polymorphisms (SNPs), IL-6-174G/C, -634G/C, and -597G/A; IL-10-1082G/A and -592C/A; IL-1beta-511C/T; NBS1 exon 5 Glu185Gln; XPC exon 15 Lys939Gln; XPD exon 23 Lys751Gln; XRCC1 exon 10 Arg399Gln; XRCC3 exon 7 Thr241Met; cyclin D1 exon 4 G870A; MTHFR exon 4 Ala222Val and exon 7 Glu429Ala; HFE exon 4 C282Y were performed by Pyrosequencing and RFLP techniques. Most of the genotype distributions were in accordance with the Hardy-Weinberg equilibrium (HWE), except for IL-10-1082G/A, where cases with BCC showed a significant deviation from HWE (P = 0.04). Linkage disequilibrium was observed between the -174 and -597 alleles in the IL-6 gene in the present populations. No difference between BCC and controls appeared in any of the SNPs analyzed. Only the combined distributions of TT/AA genotypes in MTHFR exon 4 (C/T) and exon 7 (A/C) showed slight increase in BCC compared to controls (P < 0.07, OR: 1.94; 95% CI: 0.96-3.89).     

Regional TMPRSS2 V197M Allele Frequencies Are Correlated with COVID-19 Case Fatality Rates

Coronavirus disease, COVID-19 (coronavirus disease 2019), caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), has a higher case fatality rate in European countries than in others, especially East Asian ones. One potential explanation for this regional difference is the diversity of the viral infection efficiency. Here, we analyzed the allele frequencies of a nonsynonymous variant rs12329760 (V197M) in the TMPRSS2 gene, a key enzyme essential for viral infection and found a significant association between the COVID-19 case fatality rate and the V197M allele frequencies, using over 200,000 present-day and ancient genomic samples. East Asian countries have higher V197M allele frequencies than other regions, including European countries which correlates to their lower case fatality rates. Structural and energy calculation analysis of the V197M amino acid change showed that it destabilizes the TMPRSS2 protein, possibly negatively affecting its ACE2 and viral spike protein processing.     

Immobilized Alkaline Phosphatase for Molecular Cloning

Alkaline phosphatase from E. coli was immobilized on Sepharose-4B, macroporous cellulose and chitosan-based carriers. The yields of immobilization were over 60% in most cases. It was shown that immobilized alkaline phosphatase can be used for dephosphorylation of DNA 5'-termini.