Influence of particle size on the SARS-CoV-2 spike protein detection using IgG-capped gold nanoparticles and dynamic light scattering.

Due to the unprecedented and ongoing nature of the coronavirus outbreak, the development of rapid immunoassays to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its highly contagious variants is an important and challenging task. Here, we report the development of polyclonal antibody-functionalized spherical gold nanoparticle biosensors as well as the influence of the nanoparticle sizes on the immunoassay response to detect the SARS-CoV-2 spike protein by dynamic light scattering. By monitoring the increment in the hydrodynamic diameter (ΔDH) by dynamic light scattering measurements in the antigen-antibody interaction, SARS-CoV-2 S-protein can be detected in only 5 min. The larger the nanoparticles, the larger ΔDH in the presence of spike protein. From adsorption isotherm, the calculated binding constant (K D ) was 83 nM and the estimated limit of detection was 13 ng/mL (30 pM). The biosensor was stable up to 90 days at 4 °C. Therefore, the biosensor developed in this work could be potentially applied as a fast and sensible immunoassay to detect SARS-CoV-2 infection in patient samples.

[Intra-spermatic L-carnitine and survival of sperm motility]. / L-carnitina intraspermatica e survival della motilità nemaspermica.

BACKGROUND: The aim of this work was to evaluate the intrasperm carnitine (L-C) content related to sperm motility survival in bovine cervical mucus and in culture medium (Tyrode solution). METHODS: The following subjects were selected: 15 fertile normospermic subjects (according to WHO guidelines) and 31 male partners of infertile couples (semen profile: volume > 2.0 ml; concentration > 20 x 10(6)/ml, progressive motility > or = 25% (WHO categories "a" and "b") after fluidification, abnormal forms < 70%; round cells < 1.0 x 10(6)/ml). After standard semen analysis, the samples were subdivided into three aliquots in order to carry out: a) intrasperm L-C (free, total and acetylated) assay; b) sperm motility survival in bovine cervical mucus; c) sperm motility survival in culture medium. RESULTS: A strict correlation was found between L-C (total and acetylated) content and motility survival in cervical mucus. This is probably due to the fact that in cervical mucus lipids are an important energy source for sperm and to metabolize these lipids intrasperm L-C is essential. Therefore, L-C content can be considered as an indicator of sperm motility life-span in cervical mucus. A significant correlation, even if reduced compared with cervical mucus, was also observed between L-C (total and acetylated) content and sperm motility survival in the biological medium. This probably is because the L-C system modulates the reserves of free CoA, essential to the tricarboxylic acid cycle function. CONCLUSIONS: The intrasperm L-C deficit could be due to; a) alterations in the L-C uptake mechanisms in the epididimys due to inflammatory processes; b) lack of testosterone (L-C uptake is androgen-dependent). Therefore, the therapeutic implication of this finding is that where hypomotility is due to intrasperm L-C deficit, exogenous L-C administration or improvement of L-C epididymal testosterone-dependent uptake could promote the acquisition of sperm motility.

Superoxide anion in human semen related to seminal parameters and clinical aspects.

OBJECTIVE: To study the possible presence of extracellular superoxide anion (O2-) in untreated semen of normal and pathological subjects and to determine the possible relationship between superoxide anion levels, number of seminal leukocytes (WBCs) and seminal parameters. PATIENTS: Semen samples were analyzed from fertile normospermic subjects (n = 20) and patients (n = 132) attending the Outpatient Department of the 5th Medical Clinic. MAIN OUTCOME MEASURE: We evaluated superoxide anion levels by monitoring the reduction of cytochrome c. RESULTS: O2- was detected in 55.0% of fertile normospermic subjects. Both the percentage of subjects in whom O2- was detected and the mean values +/- SD of O2- were significantly higher in the male partners of infertile couples, in subjects with varicocele, and in subjects with positive sperm culture than normospermic subjects. No variations were seen in vasectomized subjects or in patients with past cryptorchidism. A high correlation was observed between O2- levels and WBCs (rs = 0.58), nonrapid, immotile sperm (rs = 0.64), percentage decrease of motility within a specified time frame (2 to 6 hours) (rs = 0.73), and sperm abnormalities (rs = 0.49). CONCLUSIONS: Superoxide anion in untreated semen is produced by WBCs and atypical and nonrapid, immotile sperm. A significant increase of superoxide anion was detected in the male partners of infertile couples and in some selected andrological conditions. The toxic effect of superoxide anion on sperm cells is dependent on the time of exposure and superoxide anion concentration.

[Intestinal hemorrhage in a milk-fed infant: a case of laryngo-tracheo-gastric duplication]. / Emorragia intestinale in un lattante: un caso di duplicazione laringo-tracheo-gastrica.

An important gut hemorrhage in a breast fed child is not a usual event. If, in addition, the etiology represents a real rarity, even the most sophisticated diagnostic trials can't give any aid and this constitutes a hard diagnostic and therapeutic problem. In this report, the authors describe how, after a long sequence of analysis and exams, no certain diagnosis was possible, till serious anaemia gave indication to an explorative laparatomy. Laparatomy became both diagnostic and therapeutic and allowed to discover a rare malformation: a tracheal-gastric duplication.