Host-defense peptides in skin secretions of African clawed frogs (Xenopodinae, Pipidae)

African clawed frogs of the Xenopodinae (Xenopus+Silurana) constitute a well-defined system in which to study the evolutionary trajectory of duplicated genes and are a source of antimicrobial peptides with therapeutic potential. Allopolyploidization events within the Xenopodinae have given rise to tetraploid, octoploid, and dodecaploid species. The primary structures and distributions of host-defense peptides from the tetraploid frogs Xenopus borealis, Xenopus clivii, Xenopus laevis, Xenopus muelleri, "X. muelleri West", and Xenopus petersii may be compared with those from the octoploid frogs Xenopus amieti and X. andrei. Similarly, components in skin secretions from the diploid frog Silurana tropicalis may be compared with those from the tetraploid frog Silurana paratropicalis. All Xenopus antimicrobial peptides may be classified in the magainin, peptide glycine-leucine-amide (PGLa), caerulein-precursor fragment (CPF), and xenopsin-precursor fragment (XPF) families. However, the numbers of paralogs from the octoploid frogs were not significantly greater than the corresponding numbers from the tetraploid frogs. Magainins were not identified in skin secretions of Silurana frogs and the multiplicity of the PGLa, CPF, and XPF peptides from S. paratropicalis was not greater than that of S. tropicalis. The data indicate, therefore, that nonfunctionalization (gene silencing) has been the most common fate of antimicrobial peptide genes following polyploidization. While some duplicated gene products retain high antimicrobial potency (subfunctionalization), the very low activity of others suggests that they may be evolving towards a new biological role (neofunctionalization). CPF-AM1 and PGLa-AM1 from X. amieti show potential for development into anti-infective agents for use against antibiotic-resistant gram-negative bacteria.     

p63-microRNA feedback in keratinocyte senescence

We investigated the expression of microRNAs (miRNAs) associated with replicative senescence in human primary keratinocytes. A cohort of miRNAs up-regulated in senescence was identified by genome-wide miRNA profiling, and their change in expression was validated in proliferative versus senescent cells. Among these, miRNA (miR)-138, -181a, -181b, and -130b expression increased with serial passages. miR-138, -181a, and -181b, but not miR-130b, overexpression in proliferating cells was sufficient per se to induce senescence, as evaluated by inhibition of BrdU incorporation and quantification of senescence-activated β-galactosidase staining. We identified Sirt1 as a direct target of miR-138, -181a, and -181b, whereas ΔNp63 expression was inhibited by miR-130b. We also found that ΔNp63α inhibits miR-138, -181a, -181b, and -130b expression by binding directly to p63-responsive elements located in close proximity to the genomic loci of these miRNAs in primary keratinocytes. These findings suggest that changes in miRNA expression, by modulating the levels of regulatory proteins such as p63 and Sirt1, strongly contribute to induction of senescence in primary human keratinocytes, thus linking these two proteins. Our data also indicate that suppression of miR-138, -181a, -181b, and -130b expression is part of a growth-promoting strategy of ΔNp63α in epidermal proliferating cells.     

Atypical copy number abnormalities in 22q11.2 region: Report of three cases

The 22q11.2 Deletion Syndrome (22q11.2DS) is the most common microdeletion syndrome in humans, with a highly variable phenotype. This chromosomal region contains low copy repeat (LCR) sequences that mediate non-allelic homologous recombination which predispose to copy number abnormalities at this locus. This article describes three patients investigated for suspicion of 22q11.2DS presenting atypical copy number abnormalities overlapping or not with the common ～3 Mb deletion. They were investigated by G-banding karyotype, Multiplex-ligation dependent probe amplification (MLPA) and array Genomic Hibridization (aGH). Clinical and molecular data were compared with literature, in order to contribute to genotype–phenotype correlation. Atypical chromosomal abnormalities were detected: 3.6 Mb deletion at 22q11.21-q11.23 between LCRs B–F in patient 1 and approximately 1.5 Mb deletion at 22q11.21-q11.22 between LCRs D–E in patients 2 and 3. The breakpoints detected in patient 1 have not been previously described. These findings exemplify the complexity and genetic heterogeneity observed in 22q11.2 region and corroborates the idea that genetic modifiers contribute to the phenotypic variability observed in proximal and distal 22q11.2 deletion syndromes.     

Awake craniotomies without any sedation: the awake-awake-awake technique

Background

Temporary anaesthesia or analgosedation used for awake craniotomies carry substantial risks like hemodynamic instabilities, airway obstruction, hypoventilation, nausea and vomiting, agitation, and interference with test performances. We tested the actual need for sedatives and opioids in 50 patients undergoing awake craniotomy for brain tumour resection in eloquent or motoric brain areas when cranial nerve blocks, permanent presence of a contact person, and therapeutic communication are provided.

Methods

Therapeutic communication was based on the assumption that patients in such an extreme medical situation enter a natural trance-like state with elevated suggestibility. The anaesthesiologist acted as a continuous guide, using a strong rapport, nonverbal communication, hypnotic suggestions, such as dissociation to a “safe place”, and the reframing of disturbing noises, while simultaneously avoiding negative suggestions. Analgesics or sedatives were at hand according to the principle “as much as necessary, but not more than needed”.

Results

No sedation was necessary for any of the patients besides for the treatment of seizures. Only two-thirds of the patients requested remifentanil, with a mean dosage of 96 μg before the end of tumour resection and a total of 156 μg. Hemodynamic reactions indicative of stress were mainly seen during nerve blockades and neurological testing. Postoperative vigilance tests showed equal or higher scores than preoperative tests.

Conclusions

The main challenges for patients undergoing awake craniotomies include anxiety and fears, terrifying noises and surroundings, immobility, loss of control, and the feeling of helplessness and being left alone. In such situations, psychological support might be more helpful than the pharmacological approach. With adequate therapeutic communication, patients do not require any sedation and no or only low-dose opioid treatment during awake craniotomies, leaving patients fully awake and competent during the entire surgical procedure without stress. This approach can be termed “awake-awake-awake-technique”.     

The prevalence of priapism in children and adolescents with sickle cell disease in Brazil

To evaluate priapism rates in individuals <18 years of age with sickle cell disease (SCD) at a referral center. An evaluation was made of 599 consecutive male patients with SCD, separated according to type of hemoglobinopathy (HbSS, HbSC and HbS-β-thalassemia). Age at first episode and number of episodes were recorded. Cases of sickle cell trait were excluded. Mean age was similar in all groups. Overall, priapism occurred in 3.6 % of patients (5.6 % of those with HbSS and 1.1 % of those with HbSC; P = 0.01). In HbSS patients, the prevalence rate of priapism was from 3.5 (CI 95 % 0.94-13.4) when compared with patients with HbSC. No patient with β-thalassemia had priapism. Mean follow-up was 39.7 months (range 1-202 months). Since 91 % of patients with priapism had HbSS, this group was evaluated separately, revealing a rate of priapism of 1.6 % in patients <10 years and 8.3 % in those ≥ 10 years of age (P = 0.002). Regarding priapism in HbSS patients ≥ 10 years (8.3 %) when compared with patients <10 years (1.6 %), the prevalence rate was from 3.3 (CI 95 % 1.1-9.5). Duration of follow-up was not correlated with priapism (P = 0.774). Forty-seven patients were lost to follow-up. Telephone contact was successful with 14/22 patients with priapism, 50 % of whom had required hospital treatment. Most episodes (86 %) occurred at night, always during sleep. Medical interventions were required in 13 cases as follows: intravenous hydration (n = 4), corpora cavernosa puncture and drainage (n = 7) and corpus cavernosum-corpus spongiosum shunts (n = 2). The prevalence of priapism in children <18 years of age with SCD was 3.6 %, lower than previously reported. Prevalence was higher in HbSS patients, increasing in patients >10 years of age. Most episodes occurred at night and half of the patients required some form of urological procedure.