The influence of prematurity on the development of phonological skills

ABSTRACT Purpose: to check the use of phonological processes in preterm infants. Methods: phonological evaluation was performed through the ABFW Child Language Test in 40 children, aged two to four years, i.e., 20 preterm and 20 full-term children, matched according to age, gender and socioeconomic level. Preterm children were evaluated at the State Center for Prevention and Rehabilitation of People with Disabilities - CEPRED; full-term children were selected and evaluated in a municipal nursery in the city of Salvador, BA, Brazil. The pertinent statistical tests were applied adopting the level of significance lower than 0.05%. Results: in the phonology test, the number of productive phonological processes not expected for the chronological age was statistically significant in the preterm group, especially syllable reduction, consonantal harmony, velar backing and liquid reduction. The high prevalence of cluster reduction and final consonant deletion, though still compatible with chronological age, shows the need to follow up the language acquisition of these children, after the age of four. Conclusion: the results evidenced the difficulty found by preterm infants in the development of phonological skills, emphasizing the importance of early diagnosis and speech-language monitoring in language acquisition.

Neurogenic mediators contribute to local edema induced by Micrurus lemniscatus venom

Background/Aims

Micrurus is one of the four snake genera of medical importance in Brazil. Coral snakes have a broad geographic distribution from the southern United States to Argentina. Micrurine envenomation is characterized by neurotoxic symptoms leading to dyspnea and death. Moreover, various local manifestations, including edema formation, have been described in patients bitten by different species of Micrurus. Thus, we investigated the ability of Micrurus lemniscatus venom (MLV) to induce local edema. We also explored mechanisms underlying this effect, focusing on participation of neuropeptides and mast cells.

Methodology/Principal findings

Intraplantar injection of MLV (1–10 μg/paw) in rats caused dose- and time-dependent edema with a peak between 15 min and 1 h after injection. MLV also induced degranulation of peritoneal mast cells (MCs). MC depletion by compound 48/80 markedly reduced MLV-induced edema. Pre-treatment (30 min) of rats with either promethazine a histamine H₁ receptor antagonist or methysergide, a nonselective 5-HT receptor antagonist, reduced MLV-induced edema. However, neither thioperamide, a histamine H₃/H₄ receptor antagonist, nor co-injection of MLV with HOE-140, a BK₂ receptor antagonist, altered the response. Depletion of neuropeptides by capsaicin or treatment of animals with NK₁- and NK₂-receptor antagonists (SR 140333 and SR 48968, respectively) markedly reduced MLV-induced edema.

Conclusions/Significance

In conclusion, MLV induces paw edema in rats by mechanisms involving activation of mast cells and substance P-releasing sensory C-fibers. Tachykinins NKA and NKB, histamine, and serotonin are major mediators of the MLV-induced edematogenic response. Targeting mast cell- and sensory C-fiber-derived mediators should be considered as potential therapeutic approaches to interrupt development of local edema induced by Micrurus venoms.

Micrurus venoms have neurotoxic activity that is responsible for the serious sequelae in human envenomation. However, various local manifestations of envenoming have been described in patients bitten by different Micrurus species and edematogenic activity has been experimentally demonstrated. Despite the low frequency of edema in Micrurus envenomation, this effect can worsen the clinical manifestations. However, there are few studies on local inflammatory effects induced by Micrurus snake venom. We investigated the edematogenic effect of Micrurus lemniscatus venom (MLV) and participation of neuropeptides and mast cells in inflammation. Results demonstrate that MLV induces prominent edema with rapid onset. Using specific pharmacological interferences, we found that MLV-induced edema is dependent on activation of mast cells and substance P-releasing sensory C-fibers. NKA and NKB tachykinins, histamine via H₁ receptor and serotonin are major mediators of the MLV-induced edematogenic response. These findings suggest that mast cell- and C-fiber-derived mediators are promising therapeutic targets to efficiently counteract the local edema induced by Micrururs venoms.

Mechanisms involved in hearing disorders of thyroid ontogeny: a literature review

Endocochlear, retrocochlear and/or central origin hearing damage may be related to the absence of appropriate levels of thyroid hormone during morphogenesis and/or auditory system development. Hearing disorders related to the thyroid are not well studied, despite speculation on the pathophysiological mechanisms. The objective of this review was to characterize the main pathophysiological mechanisms of congenital hypothyroidism and to evaluate the relationship with central and peripheral hearing disorders. We conducted a literature review using the databases MedLine, LILACS, Cochrane Library, SciELO, Institute for Scientific Information (ISI), Embase, and Science Direct between July and September on 2016. We identified the studies that address hearing disorder mechanisms on the congenital hypothyroidism. Congenital hypothyroidism may have clinical and subclinical manifestations that affect the auditory system and may be a potential risk factor for hearing impairment. Hearing impairment can severely impact quality-of-life, which emphasizes the importance of monitoring and evaluating hearing during the clinical routine of these patients.