Photoallergic Contact Dermatitis to Sunscreens Containing Oxybenzone in La Plata, Argentina. / Dermatitis por contacto fotoalérgica a protectores solares con oxibenzona en La Plata, Argentina.

BACKGROUND: Photoallergic contact dermatitis (PACD) to oxybenzone was reported for the first time in 1980. Oxybenzone is the most common photoallergen in the United States and Canada and the fourth most common .in Europe. There are no studies or data on the prevalence of oxybenzone PACD in Argentina. OBJECTIVE: To determine the proportion of photosensitive patients with PACD to oxybenzone. METHODS: We conducted a descriptive cross-sectional study of 35 patients with photosensitivity reactions confirmed by photopatch testing at the Research Center of Hospital Público San Martín in La Plata, Argentina, in 2015 and 2016. RESULTS: PACD was identified in 6 patients (17.14%). Five of these (14.28%) had at least one positive reaction to oxybenzone in the photopatch test; 4 had a reaction at irradiated sites only (5 J/cm2 UVA) and one had a reaction at both irradiated and nonirradiated sites. CONCLUSIONS: PACD to sunscreens containing oxybenzone is common and is probably underdiagnosed due to a lack of confirmation by photopatch tests or other diagnostic tools. Sensitization rates vary according to region and are influenced by sunscreen ingredients and variations in the use of sunscreen products, cosmetics, and topical drugs.

Extracellular Tau Oligomers Produce An Immediate Impairment of LTP and Memory.

Non-fibrillar soluble oligomeric forms of amyloid-ß peptide (oAß) and tau proteins are likely to play a major role in Alzheimer's disease (AD). The prevailing hypothesis on the disease etiopathogenesis is that oAß initiates tau pathology that slowly spreads throughout the medial temporal cortex and neocortices independently of Aß, eventually leading to memory loss. Here we show that a brief exposure to extracellular recombinant human tau oligomers (oTau), but not monomers, produces an impairment of long-term potentiation (LTP) and memory, independent of the presence of high oAß levels. The impairment is immediate as it raises as soon as 20 min after exposure to the oligomers. These effects are reproduced either by oTau extracted from AD human specimens, or naturally produced in mice overexpressing human tau. Finally, we found that oTau could also act in combination with oAß to produce these effects, as sub-toxic doses of the two peptides combined lead to LTP and memory impairment. These findings provide a novel view of the effects of tau and Aß on memory loss, offering new therapeutic opportunities in the therapy of AD and other neurodegenerative diseases associated with Aß and tau pathology.

In vivo protective effect of ferulic acid against noise-induced hearing loss in the guinea-pig.

Ferulic acid (FA) is a phenolic compound whose neuroprotective activity was extensively studied in vitro. In this study, we provided functional in vivo evidence that FA limits noise-induced hearing loss. Guinea-pigs exposed to acoustic trauma for 1 h exhibited a significant impairment in auditory function; this injury was evident as early as 1 day from noise exposure and persisted over 21 days. Ferulic acid (150 mg/kg i.p. for 4 days) counteracted noise-induced hearing loss at days 1, 3, 7 and 21 from noise exposure. The improvement of auditory function by FA was paralleled by a significant reduction in oxidative stress, apoptosis and increase in hair cell viability in the organ of Corti. Interestingly in the guinea-pig cochleae, the neuroprotective effect of FA was functionally related not only to its scavenging ability in the peri-traumatic period but also to the up-regulation of the cytoprotective enzyme heme oxygenase-1 (HO-1); in fact, FA-induced improvement of auditory function was counteracted by the HO inhibitor zinc-protoporphyrin-IX and paralleled the time-course of HO-1 induction over 3-7 days. These results confirm the antioxidant properties of FA as free-radical scavenger and suggest a role of HO-1 as an additional mediator against noise-induced ototoxicity.

Correlation between endometrial biopsy and luteal phase plasma progesterone in women complaining for couple infertility.

One hundred forty-three women complaining for couple infertility (more than 2 yr), were investigated for luteal phase deficiency (i.e. insufficient endometrial luteinization) by endometrial biopsy and serial determinations (in days -10, -7 and -4 respect the onset of the next menses) of plasma progesterone during luteal phase. One hundred-three women had the first endometrial biopsy in phase (IP), 36 had the biopsy "out of phase" (OOP). Among them 13 did not repeat endometrial biopsy, 12 had the second biopsy out of phase (and then classified as Luteal Phase Deficiency) and 11 had the second biopsy "in phase". Only the women affected by luteal phase deficiency had the plasma progesterone (mean of 3 samples) significantly lower than that of infertile women with normal endometrial luteinization. However the majority of the individual progesterone values of these two groups overlapped. The endometrial biopsy seems to be the most practicable method for investigating luteal phase deficiency in women complaining for couple infertility.

Hysteroscopy and endometrial biopsy.

The role of hysteroscopy for a complete evaluation of luteal phase is discussed by the authors. They affirm that for a thorough evaluation a hysteroscopy may be usefully performed simultaneously to the endometrial biopsy.