Pathological changes of the skin and the oral mucosa during pregnancy : part II

The specific physiological or pathological changes of the skin and mucous membranes can occur during pregnancy. Also the effect of pregnancy on some skin disorders is highly variable and are not predictable, some of the skin conditions may improve while others are aggravated. The changes in the course of the skin and mucous membranes disorders during pregnancy were presented, based on data from literature. The choice of the therapy during pregnancy is an important\ud management option

Pathological changes of the skin and the oral mucosa during pregnancy : part I

The study describes, on the basis of the literature, various pathological changes which appear only on the oral mucosa as well as on the oral mucosa and the skin during pregnancy. Diagnostic methods, clinical symptoms of the described diseases and proper local therapy (of the pathological changes in the oral cavity) are discussed

Nesfatin-1 : a new hormone in the control of food intake and the mechanism of damage and protection of gastric mucosa

Nesfatyna 1 jest 82-aminokwasowym peptydem powstałym w wyniku potranslacyjnej hydrolizy N-końcowego fragmentu innego białka nucleobindin2 (NUCB2), będącego prekursorem dla nesfatyny 1 o rozpoznanej i ustalonej sekwencji aminokwasów, występującej powszechnie wśród ssaków. Interesujący jest fakt, że genową ekspresję peptydowego układu NUCB2/nesfatyna 1 zaobserwowano w przewodzie pokarmowym gryzoni, zwłaszcza w błonie śluzowej szczurzego żołądka, szczególnie w bliskiej lokalizacji komórek neuroendokrynnych części trzonowej odpowiedzialnych m.in. za uwalnianie greliny. Pierwotnie wykryto, że NUCB2 i nesfatyna 1 podawane do komór bocznych mózgu hamują przyjmowanie pokarmu w fazie nocnej u szczurów i że efekt ten jest połączony ze zmniejszeniem masy ciała tych zwierząt, co sugeruje, że nesfatyna 1 jest peptydem anoreksygenicznym, hamującym apetyt. Dalsze badania nad fizjologicznym znaczeniem nesfatyny 1 dowodzą, że podobnie jak w przypadku innych hormonów pobudzających apetyt (np. grelina) czy hamujących apetyt (np. leptyna), peptyd ten odznacza się właściwościami gastroprotekcyjnymi i chroni błonę śluzową żołądka przed uszkodzeniami indukowanymi przez czynniki korozyjne oraz mikrokrwawienia wywoływane przez stres. W ten gastroprotekcyjny mechanizm działania nesfatyny 1 zaangażowane są układy endogennych prostaglandyn (PG) uwalnianych na drodze aktywacji cyklooksygenaz (COX) - COX-1 i COX-2 - oraz tlenku azotu (NO) produkowanego przez enzymy syntaz NO, odpowiedzialne za wzrost żołądkowego przepływu krwi, któremu towarzyszy wzrost stężenia nesfatyny 1 w osoczu. Podsumowując - endogenne PG i NO są mediatorami gastroprotekcji i przekrwienia obserwowanego w błonie śluzowej żołądka szczurów pod wpływem nesfatyny 1. Dlatego autorzy sądzą, że dalsze badania, zwłaszcza kliniczne, mające na celu poznanie mechanizmu działania i wyjaśnienie roli nesfatyny 1 w przewodzie pokarmowym powinny rzucić nieco więcej światła na problem potencjalnego terapeutycznego wykorzystania tego peptydu w zapobieganiu uszkodzeniom żołądka, w tym mikrokrwawieniom żołądkowym u ludzi.Nesfatin-1 is an 82-amino-acid peptide derived from posttranslational processing of the N-terminal fragment of nucleobindin 2 (NUCB2), a protein precursor for nesfatin-1, which is highly conserved across mammalian species. The expression of NUCB2/nesfatin-1 has been detected in the stomach, most prominently within ghrelin cells of the rat gastric oxyntic mucosa. The first biological action ascribed to NUCB2 and nesfatin-1 was the reduction of dark-phase food intake with a concomitant reduction in body weight gain when these peptides were injected intracerebroventricularly, suggesting their anorexigenic action in rodents. Studies on the potential physiological importance of nesfatin-1 have shown that nesfatin1, similarly as for other appetite peptides such as ghrelin and leptin studied before, exerts protective activity against gastric mucosal lesions induced by topical damaging agents and seems to be also effective against those caused by stress. This gastroprotective action of exogenous nesfatin-1 may involve the activation of PG/COX and NO/NOS systems, resulting in an increase in gastric blood flow accompanied by a rise in plasma nesfatin-1 levels. Thus, it is concluded that 1) endogenous PG and NO may mediate the nesfatin-1- induced gastroprotection in the rat stomach, and 2) clinical studies regarding the potential benefit of nesfatin-1 observed in animals should shed more light on the efficacy of this peptide to prevent gastric disorders including the formation of gastric microbleeding in humans

RuvC uses dynamic probing of the Holliday junction to achieve sequence specificity and efficient resolution

Holliday junctions (HJs) are four-way DNA structures that occur in DNA repair by homologous recombination. Specialized nucleases, termed resolvases, remove (i.e., resolve) HJs. The bacterial protein RuvC is a canonical resolvase that introduces two symmetric cuts into the HJ. For complete resolution of the HJ, the two cuts need to be tightly coordinated. They are also specific for cognate DNA sequences. Using a combination of structural biology, biochemistry, and a computational approach, here we show that correct positioning of the substrate for cleavage requires conformational changes within the bound DNA. These changes involve rare high-energy states with protein-ssisted base flipping that are readily accessible for the cognate DNA sequence but not for non-cognate sequences. These conformational changes and the relief of protein-induced structural tension of the DNA facilitate coordination between the two cuts. The unique DNA cleavage mechanism of RuvC demonstrates the importance of high-energy conformational states in nucleic acid readout

SARS-CoV-2 infects an <I>in vitro</I> model of the human developing pancreas through endocytosis

Recent studies showed that SARS-CoV-2 can infect adult human pancreas and trigger pancreatic damage. Here, using human fetal pancreas samples and 3D differentiation of human pluripotent cells into pancreatic endocrine cells, we determined that SARS-CoV-2 receptors ACE2, TMPRSS2, and NRP1 are expressed in precursors of insulin-producing pancreatic β-cells, rendering them permissive to SARS-CoV-2 infection. We also show that SARS-CoV-2 enters and undergoes efficient replication in human multipotent pancreatic and endocrine progenitors in vitro. Moreover, we investigated mechanisms by which SARS-CoV-2 enters pancreatic cells, and found that ACE2 mediates the entry, while NRP1 and TMPRSS2 do not. Surprisingly, we found that in pancreatic progenitors, SARS-CoV-2 enters cells via cathepsin-dependent endocytosis, which is a different route than in respiratory tract. Therefore, pancreatic spheroids might serve as a model to study candidate drugs for endocytosis-mediated viral entry inhibition and to investigate whether SARS-CoV-2 infection may affect pancreas development, possibly causing lifelong health consequences