Validated spectrofluorimetric method for the determination of netilmicin based on its interaction with o-phthalaldehyde/mercaptoethanol: Evaluation of the method's greenness

In this study, netilmicin (NTM) was selectively assessed in its dosage forms after a facile derivatization reaction. The proposed approach was based on the interaction between NTM and o-phthalaldehyde/2-mercaptoethanol (Roth's reagent). The reaction product was fluorometrically measured at λ_emission of 434 nm after λ_excitation of 338 nm. All reaction conditions for achieving the optimum fluorescence switch-on activity were visualized and monitored. Moreover, the method was validated under ICH guidelines, and was linear over the range 30–210 ng/ml after plotting netilmicin concentrations against the corresponding fluorescence intensity values. In addition, the selectivity of the developed method was investigated against either the co-formulated drug (dexamethasone) or a common ophthalmic drop excipient (benzalkonium chloride) without interference from either of them. Furthermore, the developed method was applied to assay netilmicin in various samples of pharmaceutical eye drops with good recovery. Finally, multicriteria greenness and whiteness metrics were used to evaluate the sustainability, greenness, and whiteness of the approach. The applied tools were the AGREE algorithm, the RGB 12 algorithm, and HEXAGON.     

Effects of a selectively bred novelty-seeking phenotype on the motivation to take cocaine in male and female rats

Background

Although colorectal cancer (CRC) is generally not considered to be a hormone-dependent malignancy, several sex-related differences in incidence, molecular characteristics and survival have been reported. Epidemiological studies have consistently shown that increased exposure to female sex hormones is associated with a lower risk of CRC in women, and cyclin D1, an important downstream effector in estrogen-mediated signaling, is commonly activated in CRC. In this study, we analyzed the prognostic significance of cyclin D1 expression in CRC, with particular reference to sex-related differences, in tumors from a large, prospective, population-based cohort.

Methods

Using tissue microarrays and immunohistochemistry, the fraction and intensity of cyclin D1 expression was evaluated in 527 incident CRC cases from the Malmö Diet and Cancer Study. The χ² and Spearman's rho (ρ) tests were used for comparison of cyclin D1 expression and relevant clinicopathological characteristics. Kaplan-Meier analysis and Cox proportional hazards modeling were used to assess the effect of cyclin D1 expression on cancer-specific survival (CSS) in univariate and multivariate analysis, adjusted for established prognostic factors.

Results

Cyclin D1 intensity was significantly lower in male compared with female CRC (P = 0.018). In the full cohort, cyclin D1 expression was associated with a significantly prolonged CSS (hazard ratio (HR) = 0.69; 95% CI 0.49 to 0.96, P = 0.026) but subgroup analysis according to gender revealed a strongly accentuated prognostic effect of cyclin D1 in male CRC (HR = 0.48; 95% CI 0.31 to 0.74, P < 0.001), which was in contrast to female CRC, where cyclin D1 was not prognostic (HR = 1.05; 95% CI 0.62 to 1.78, P = 0.864) (P _interaction = 0.024). The prognostic value of cyclin D1 was not retained in multivariate analysis, either in the full cohort or in male CRC.

Conclusions

Cyclin D1 expression is strongly associated with prolonged survival in male CRC. These findings not only support an important role for cyclin D1 in colorectal carcinogenesis, but also add further weight to the accumulating evidence that CRC is indeed a hormone-dependent malignancy, for which prognostic and treatment-predictive molecular biomarkers should be evaluated differently in women and men.     

Truncation of the E3 ubiquitin ligase component FBXO31 causes non-syndromic autosomal recessive intellectual disability in a Pakistani family

In this study, we have performed autozygosity mapping on a large consanguineous Pakistani family segregating with intellectual disability. We identified two large regions of homozygosity-by-descent (HBD) on 16q12.2–q21 and 16q24.1–q24.3. Whole exome sequencing (WES) was performed on an affected individual from the family, but initially, no obvious mutation was detected. However, three genes within the HBD regions that were not fully captured during the WES were Sanger sequenced and we identified a five base pair deletion (actually six base pairs deleted plus one base pair inserted) in exon 7 of the gene FBXO31. The variant segregated completely in the family, in recessive fashion giving a LOD score of 3.95. This variant leads to a frameshift and a premature stop codon and truncation of the FBXO31 protein, p.(Cys283Asnfs*81). Quantification of mRNA and protein expression suggests that nonsense-mediated mRNA decay also contributes to the loss of FBXO31 protein in affected individuals. FBXO31 functions as a centrosomal E3 ubiquitin ligase, in association with SKP1 and Cullin-1, involved in ubiquitination of proteins targeted for degradation. The FBXO31/SKP1/Cullin1 complex is important for neuronal morphogenesis and axonal identity. FBXO31 also plays a role in dendrite growth and neuronal migration in developing cerebellar cortex. Our finding adds further evidence of the involvement of disruption of the protein ubiquitination pathway in intellectual disability.