Consumption of freshwater fish: A variable but significant risk factor for PFOS exposure

PFOS, PFOA, PFNA and PFHxS are the PFAS substances that currently contribute most to human exposure, and in 2020 the European Food Safety Authority (EFSA) presented a draft opinion on a tolerable intake of 8 ng/kg/week for the sum of these four substances (equaling 0.42 μg/kg if expressed as an annual dose). Diet is usually the dominating exposure pathway, and in particular the intake of PFOS has been shown to be strongly related to the consumption of fish and seafood. Those who eat freshwater fish may be especially at risk since freshwater and its biota typically display higher PFOS concentrations than marine systems. In this study, we estimated the range in PFOS intake among average Swedish "normal" and "high" consumers of freshwater fish. By average we mean persons of average weight who eat average-sized portions. The "normal consumers" were assumed to eat freshwater fish 3 times per year, and the "high consumers" once a week. Under these assumptions, the yearly tolerable intake for "normal" and "high" consumers is reached when the PFOS concentrations in fish equals 59 and 3.4 μg per kg fish meat. For this study, PFOS concentrations in the muscle tissue of edible-sized perch, pike and pikeperch were retrieved from three different Swedish datasets, covering both rural and urban regions and a total of 78 different inland waters. Mean PFOS concentrations in fish from these sites varied from 0.3 to 750 μg/kg. From the available data, the annual min-max dietary PFOS intake for male "normal consumers" was found to be in the range 0.0021-5.4 μg/kg/yr for the evaluated scenarios, with median values of 0.02-0.16 μg/kg/yr. For male "high consumers", the total intake range was estimated to be 0.04-93 μg/kg/yr, with median values being 0.27-1.6 μg/kg/yr. For women, the exposure estimates were slightly lower, about 79% of the exposure in men. Despite highly variable PFOS concentrations in fish from different sites, we conclude that the three most commonly consumed freshwater species in Sweden constitute an important source for the total annual intake even for people who eat this kind of fish only a few times per year. The analyses of PFOA, PFNA and PFHxS showed values which were all below detection limit, and their contribution to the total PFAS intake via freshwater fish consumption is negligible in comparison to PFOS.

Chronic Diarrhea in L-Amino Acid Decarboxylase (AADC) Deficiency: A Prominent Clinical Finding Among a Series of Ten French Patients

Aromatic L-amino acid decarboxylase (AADC) deficiency is an autosomal recessive inborn error of metabolism, affecting catecholamines and serotonin biosynthesis. Cardinal signs consist in psychomotor delay, hypotonia, oculogyric crises, dystonia, and extraneurological symptoms.

PATIENTS AND METHODS

We present a retrospective descriptive multicentric study concerning ten French children with a biochemical and molecular confirmed diagnosis of AADC deficiency.

RESULTS

Clinical presentation of most of our patients was consistent with the previous descriptions from the literature (hypotonia (nine children), autonomic signs (nine children), sleep disorders (eight children), oculogyric crises (eight children), motor disorders like hypertonia and involuntary movements (seven children)). We described however some phenotypic particularities. Two patients exhibited normal intellectual abilities (patients already described in the literature). We also underlined the importance of digestive symptoms like diarrhea, which occurred in five among the ten patients. We report in particular two children with chronic diarrhea, complicated by severe failure to thrive. Vanillactic acid (VLA) elevation in urines of one of these two patients led to suspect the diagnosis of AADC deficiency, as in two other patients from our population.

CONCLUSION

Some symptoms like chronic diarrhea were atypical and have been poorly described in the literature up to now. Diagnosis of the AADC deficiency is sometimes difficult because of the phenotypic heterogeneity of the disease and VLA elevation in urines should suggest the diagnosis.

Cross-subtype neutralization sensitivity despite monoclonal antibody resistance among early subtype A, C, and D envelope variants of human immunodeficiency virus type 1

The human immunodeficiency virus type 1 (HIV-1) variants that are transmitted to newly infected individuals are the primary targets of interventions, such as vaccines and microbicides, aimed at preventing new infections. Newly acquired subtype A, B, and C variants have been the focus of neutralization studies, although many of these viruses, particularly of subtypes A and B, represent viruses circulating more than a decade ago. In order to better represent the global diversity of transmitted HIV-1 variants, an additional 31 sexually transmitted Kenyan HIV-1 env genes, representing several recent infections with subtype A, as well as subtypes A/D, C, and D, were cloned, and their neutralization profiles were characterized. Most env variants were resistant to neutralization by the monoclonal antibodies (MAbs) b12, 4E10, 2F5, and 2G12, suggesting that targeting the epitopes of these MAbs may not be effective against variants that are spreading in areas of endemicity. However, significant cross-subtype neutralization by plasma was observed, indicating that there may be other epitopes, not yet defined by the limited available MAbs, which could be recognized more broadly.

Human immunodeficiency virus type 1 superinfection occurs despite relatively robust neutralizing antibody responses

Superinfection by a second human immunodeficiency virus type 1 (HIV-1) strain indicates that gaps in protective immunity occur during natural infection. To define the role of HIV-1-specific neutralizing antibodies (NAbs) in this setting, we examined NAb responses in 6 women who became superinfected between approximately 1 to 5 years following initial infection compared to 18 women with similar risk factors who did not. Although superinfected individuals had less NAb breadth than matched controls at approximately 1 year postinfection, no significant differences in the breadth or potency of NAb responses were observed just prior to the second infection. In fact, four of the six subjects had relatively broad and potent NAb responses prior to infection by the second strain. To more specifically examine the specificity of the NAbs against the superinfecting virus, these variants were cloned from five of the six individuals. The superinfecting variants did not appear to be inherently neutralization resistant, as measured against a pool of plasma from unrelated HIV-infected individuals. Moreover, the superinfected individuals were able to mount autologous NAb responses to these variants following reinfection. In addition, most superinfected individuals had NAbs that could neutralize their second viral strains prior to their reinfection, suggesting that the level of NAbs elicited during natural infection was not sufficient to block infection. These data indicate that preventing infection by vaccination will likely require broader and more potent NAb responses than those found in HIV-1-infected individuals.

Organochlorine pesticides and PCBs along the coast of north Vietnam

Organochlorine pesticides and polychlorinated biphenyls (PCBs) were determined in sediments and clams collected from the coast of the north of Vietnam during the rainy season (August-September 1997). Results show that the organochlorine pesticides of major concern are HCHs (1.2-33.7 ng g-1 dry wt.), DDTs (6.2-10.4 ng g-1 dry wt.) and HCB (0.1-6.5 ng g-1 dry wt.). PCBs, in aroclor 1254 equivalents, were also generally present in concentrations ranging from 0.47 to 28.1 ng g-1 sediment dry wt. Concentrations measured in the soft tissues of clams (Meretrix meretrix) generally reflect the level of contamination at the sampling sites. In the clams, the concentrations of DDTs (12.0-23.3 ng g-1 dry wt.) and PCBs (5.1-25.3 ng g-1 dry wt.) were generally higher than those of other chlorinated hydrocarbons. These results underscore the need to improved environmental protection measures in order to reduce the exposure of the population to these persistent and bioaccumulative compounds through food ingestion.

A profile of the behavioral changes produced by facilitation of AMPA-type glutamate receptors

A newly developed group of benzoylpiperidine drugs that enhance AMPA-receptor-gated currents ("ampakines") has been shown to improve memory encoding in rats across a variety of experimental paradigms. The present experiments were intended to i) provide a partial profile of the behavioral changes produced by ampakines, ii) test if two ampakines (BDP-12 and BDP-20) that differ significantly in their effects on AMPA receptor kinetics produce similar behavioral profiles, and iii) determine if physiological potency is reflected in behavioral potency. BDP-20 reduced two measures of exploratory activity in aged rats but increased speed of performance in a radial maze; the drug also caused substantially improved retention of spatial information. These results are similar to those obtained with BDP-12, an analog that differs from BDP-20 in its effects on ligand binding to the AMPA receptor and on the physiological responses of the receptors to glutamate. BDP-20 was approximately ten-fold more potent in behavioral effects than BDP-12, which agrees with the relative potencies of the two drugs as assessed with excised patches and excitatory synaptic responses. These findings indicate that ampakines, though differing in their effects on AMPA-receptor-mediated responses, have similar effects at the behavioral level.

A comparative study of the biologic and immunologic response to medical devices derived from dermal collagen

We examined collagen materials for soft tissue augmentation [Zyderm Collagen Implant (ZCI), glutaraldehyde cross-linked (GAX) collagen, and Koken Atelocollagen (Atelocollagen)]; hemostatic collagens [Gelfoam Gelatin Powder (Gelfoam), Avitene Microfibrillar Collagen Hemostat (Avitene), and Collastat Collagen Hemostat (Collastat)]; and reconstituted, intact fibrillar collagen from bovine skin in a subcutaneous guinea pig model. After 11, 25, and 39 days in situ, explants from animals injected with GAX collagen demonstrated greater wet-weight persistence than all other materials. Conversely, at all time points, the explants of Atelocollagen were the least persistent. Following 25 days in vivo, explants were examined using differential scanning calorimetry; ZCI and Atelocollagen displayed thermal transition temperatures of 58 degrees C. Avitene and Gelfoam explants displayed transition points of 30 degrees C and 32 degrees C, indicating denatured or cleaved collagen. By contrast, GAX collagen explants had a high (68 degrees C) transition temperature, reflecting its cross-linking. With respect to immunogenicity, day 39 sera from ZCI treated animals showed significantly lower titers in the ELISA to their respective implant collagen than all other groups examined, while antibody activity in the GAX collagen, Gelfoam, Atelocollagen, and intact collagen groups were not significantly different. Collastat elicited antibodies with a greater affinity than observed in these previous groups. Sera from Avitene treated animals demonstrated the highest antibody levels and were the only sera which reacted with bovine serum albumin. Thus, Avitene was the most immunogenic of the collagen materials examined, while GAX collagen demonstrated the greatest persistence and minimal immunogenicity, and ZCI was the least immunogenic.