Effects of Endolithic Parasitism on Invasive and Indigenous Mussels in a Variable Physical Environment

Biotic stress may operate in concert with physical environmental conditions to limit or facilitate invasion processes while altering competitive interactions between invaders and native species. Here, we examine how endolithic parasitism of an invasive and an indigenous mussel species acts in synergy with abiotic conditions of the habitat. Our results show that the invasive Mytilus galloprovincialis is more infested than the native Perna perna and this difference is probably due to the greater thickness of the protective outer-layer of the shell of the indigenous species. Higher abrasion due to waves on the open coast could account for dissimilarities in degree of infestation between bays and the more wave-exposed open coast. Also micro-scale variations of light affected the level of endolithic parasitism, which was more intense at non-shaded sites. The higher levels of endolithic parasitism in Mytilus mirrored greater mortality rates attributed to parasitism in this species. Condition index, attachment strength and shell strength of both species were negatively affected by the parasites suggesting an energy trade-off between the need to repair the damaged shell and the other physiological parameters. We suggest that, because it has a lower attachment strength and a thinner shell, the invasiveness of M. galloprovincialis will be limited at sun and wave exposed locations where endolithic activity, shell scouring and risk of dislodgement are high. These results underline the crucial role of physical environment in regulating biotic stress, and how these physical-biological interactions may explain site-to-site variability of competitive balances between invasive and indigenous species

Intestinal carriage of Staphylococcus aureus: How does its frequency compare with that of nasal carriage and what is its clinical impact?

The bacterial species Staphylococcus aureus, including its methicillin-resistant variant (MRSA), finds its primary ecological niche in the human nose, but is also able to colonize the intestines and the perineal region. Intestinal carriage has not been widely investigated despite its potential clinical impact. This review summarizes literature on the topic and sketches the current state of affairs from a microbiological and infectious diseases' perspective. Major findings are that the average reported detection rate of intestinal carriage in healthy individuals and patients is 20% for S. aureus and 9% for MRSA, which is approximately half of that for nasal carriage. Nasal carriage seems to predispose to intestinal carriage, but sole intestinal carriage occurs relatively frequently and is observed in 1 out of 3 intestinal carriers, which provides a rationale to include intestinal screening for surveillance or in outbreak settings. Colonization of the intestinal tract with S. aureus at a young age occurs at a high frequency and may affect the host's immune system. The frequency of intestinal carriage is generally underestimated and may significantly contribute to bacterial dissemination and subsequent risk of infections. Whether intestinal rather than nasal S. aureus carriage is a primary predictor for infections is still ill-defined

Extensa falha cutânea e craniana em paciente com aplasia cutis congenita Large scalp and skull defect in patient with aplasia cutis congenita

Aplasia cutis congenita (ACC) é doença rara, caracterizada pela ausência de formação completa da pele. Geralmente ocorre no couro cabeludo, na linha mediana, e apresenta-se ao nascimento como uma ferida ulcerada que pode atingir diferentes profundidades e envolver o periósteo, crânio e dura-máter. Descrevemos o caso de menina recem-nascida que apresentava fácies dismórfica com defeito no couro cabeludo que abrangia a quase totalidade da abóbada craniana e apresentava falha óssea desde a base dos ossos frontais até os occipitais e mastóides. A dura-máter estava em sua maior parte exposta, sem sinais de fissuras. Devido à raridade da ACC e ao pequeno número de pacientes nas séries publicadas na literatura a padronização do tratamento ainda é incipiente. O que existem são recomendações. Ainda são necessários estudos que abordem desde a etiologia da doença até a avaliação dos métodos de tratamento e evolução de grupos maiores de pacientes.<br>Aplasia cutis congenita is a rare condition characterized by the absence of skin layers. It is most common on the scalp, middle line, and it can be seen as a congenital ulcer involving periosteum, skull and dura. We present the case of a female newborn infant with a dysmorphic facies, a large scalp and skull defect exposing the dura. There was no cerebrospinal fluid leakage. The rarity of cases with large defects and small series reported make difficult to determinate the ideal treatment for aplasia cutis congenita. More studies are necessary to define the etiology and best management of this patients

Effect of High-Dose Simvastatin on Cerebral Blood Flow and Static Autoregulation in Subarachnoid Hemorrhage

BACKGROUND: Statins may promote vasodilation following subarachnoid hemorrhage (SAH) and improve the response to blood pressure elevation. We sought to determine whether simvastatin increases cerebral blood flow (CBF) and alters the response to induced hypertension after SAH. METHODS: Statin-naïve patients admitted <72 hours after WFNS ≥2 aneurysmal SAH were randomly assigned to 80 mg simvastatin/day or placebo for 21 days. Regional cerebral blood flow (CBF) was measured with quantitative (15)O PET on SAH day 7–10 before and after raising mean arterial pressure (MAP) 20–25%. Autoregulatory index (AI) was calculated as the ratio of % change in resistance (MAP/CBF) to % change in MAP. Angiography was performed within 24 hours of PET. Results are presented as simvastatin vs. placebo. RESULTS: Thirteen patients received simvastatin and 12 placebo. Clinical characteristics were similar. Moderate or severe angiographic vasospasm occurred in 42% vs.45% and delayed cerebral ischemia in 14% vs. 55% (p=0.074). During PET studies MAP (110±10 vs. 111±12), global CBF (41±12 vs. 43±13) and CVR (2.95±1.0 vs. 2.81±1.0) did not differ at baseline. When MAP was raised to 135±7 mm Hg vs. 137±15, global CBF did not change. Global AI did not differ (107±59 % vs 0. 89±52 %, p=0.68). CBF did not change in regions with low baseline flow or in regions supplied by vessels with angiographic vasospasm in either group. Six month modified Rankin Scale scores did not differ. CONCLUSIONS: Our data indicate that initiation of therapy with high-dose simvastatin does not alter baseline CBF or response to induced hypertension

Nrf2-interacting nutrients and COVID-19 : time for research to develop adaptation strategies

There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPAR gamma:Peroxisome proliferator-activated receptor, NF kappa B: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2 alpha:Elongation initiation factor 2 alpha). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT(1)R axis (AT(1)R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity.Peer reviewe