Protein phosphatase 1 (PP1) is expressed in all eukaryotic cells and catalyzes a substantial fraction of phosphoserine/threonine dephosphorylation reactions. It forms stable complexes with PP1-interacting proteins (PIPs) that guide the phosphatase throughout its life cycle and control its fate and function. The diversity of PIPs is huge (≈200 in vertebrates), and most of them combine short linear motifs to form large and unique interaction interfaces with PP1. Many PIPs have separate domains for PP1 anchoring, PP1 regulation, substrate recruitment and subcellular targeting, which enable them to direct associated PP1 to a specific subset of substrates and mediate acute activity control. Hence, PP1 functions as the catalytic subunit of a large number of multimeric holoenzymes, each with its own subset of substrates and mechanism(s) of regulation.

Understanding physicians’ antibiotic-prescribing behaviour is fundamental when it comes to improving antibiotic use and tackling the growing rates of antimicrobial resistance. The aim of the study was to develop and validate -in terms of face validity, content validity and reliability- an instrument designed to assess the attitudes and knowledge underlying physician antibiotic prescribing. The questionnaire development and validation process comprised two different steps, namely: (1) content and face validation, which included a literature review and validation both by physicians and by Portuguese language and clinical psychology experts; and (2) reliability analysis, using the test-retest method, to assess the questionnaire’s internal consistency (Cronbach’s alpha) and reproducibility (intraclass correlation coefficient - ICC). The questionnaire includes 17 items assessing attitudes and knowledge about antibiotic prescribing and resistances and 9 items evaluating the importance of different sources of knowledge. The study was conducted in the catchment area covered by Portugal’s Northern Regional Health Administration and used a convenience sample of 61 primary-care and 50 hospital-care physicians. Response rate was 64 % (49 % to retest) for primary-care physicians and 66 % (60 % to retest) for hospital-care physicians. Content validity resulted in 9 changes to professional concepts. Face validity assessment resulted in 19 changes to linguistic and interpretative terms. In the case of the reliability analysis, the ICC values indicated a minimum of fair to good reproducibility (ICC > 0.4), and the Cronbach alpha values were satisfactory (α > 0.70). The questionnaire developed is valid -in terms of face validity, content validity and reliability- for assessing physicians’ attitudes to and knowledge of antibiotic prescribing and resistance, in both hospital and primary-care settings, and could be a very useful tool for characterising physicians’ antibiotic-prescribing behaviour.

In order to assess the effect of arsenic on the male reproductive impairment in mice, 7-week-old animals were exposed to 7.5 mg sodium arsenite (NaAsO₂)/kg body weight, during 35 days (one spermatogenic cycle). One group of animals was sacrificed after exposure, while another group received distilled water for an additional period of 35 days, in order to study the spermatoxic effect and the recovery of spermatogenesis. In mice sacrificed after NaAsO₂ exposure, a decrease in testis/body weight ratio and reduction of tubular diameter were observed. Both groups of NaAsO₂-exposed animals showed remarkable histopathological changes, such as sloughing of immature germ cells. Animals sacrificed after NaAsO₂ exposure showed decreased sperm motility, increased abnormal sperm morphology and decreased sperm viability. The effects of NaAsO₂ on sperm motility recovered to normal values after one spermatogenic cycle, while increased sperm abnormality was maintained. However, at this period, a decrease in acrosome integrity was detected. Concerning oxidative stress parameters, animals sacrificed after NaAsO₂ exposure showed a decreased selenium-dependent glutathione peroxidase activity, which was not detected after the recovery. Conversely, at this period, total glutathione peroxidase activity increased in exposed animals. These results demonstrate the toxic effects of NaAsO₂ on mice spermatogenesis and show the lack of recovery after one spermatogenic cycle.

Objectives Antibiotic misprescription is a major driver of resistance, which is a worldwide public health problem. Therefore, our aim is to assess the influence of the determinants of physician pre...

Nuclear Inhibitor of PP1 (NIPP1) is a conserved regulatory subunit of protein phosphatase PP1. The selective deletion of NIPP1 in mouse liver parenchymal cells or skin epidermal cells culminates in a late-onset hyperproliferation of a subset of resident progenitor cells. Although a hyperplastic phenotype is usually tumor promoting, we show here that the absence of NIPP1 conferred a strong resistance to chemically induced hepatocellular or skin carcinoma. The ablation of NIPP1 did not affect the metabolism of the administered mutagens (diethylnitrosamine or 7,12-dimethylbenz[a]anthracene), but reduced the conversion of mutagen-induced covalent DNA modifications into cancer-initiating mutations. This reduced sensitivity to mutagens correlated with an enhanced DNA-damage response and an augmented expression of rate-limiting DNA-repair proteins (MGMT in liver, XPD and XPG in skin), hinting at an increased DNA-repair capacity. Our data identify NIPP1 as a repressor of DNA repair and as a promising target for novel cancer prevention and treatment therapies.