Thickness of multiwalled carbon nanotubes affects their lung toxicity.

Two samples of highly pure multiwalled carbon nanotubes (MWCNTs) similar in hydrophobicity and surface reactivity were prepared with similar length, <5 µm, but markedly different diameter (9.4 vs 70 nm). The samples were compared for their cytotoxic activity, uptake, and ability to induce oxidative stress (ROS production and intracellular GSH depletion) in vitro in murine alveolar macrophages (MH-S). The in vivo toxicity was evaluated by measuring biochemical (LDH activity and total proteins) and cellular responses in bronchoalveolar lavage (BAL) after intratracheal instillation in rats. Both samples were internalized in MH-S cells. However, thin MWCNTs appeared significantly more toxic than the thicker ones, both in vitro and in vivo, when compared on a mass-dose basis. The data reported herein suggest that the nanotube diameter is an important parameter to be considered in the toxicological assessment of CNTs.

Spectrum of Kidney Injury Following COVID-19 Disease: Renal Biopsy Findings in a Single Italian Pathology Service.

The onset of coronavirus disease (COVID-19) as a pandemic infection, has led to increasing insights on its pathophysiology and clinical features being revealed, such as a noticeable kidney involvement. In this study, we describe the histopathological, immunofluorescence, and ultrastructural features of biopsy-proven kidney injury observed in a series of SARS-CoV-2 positive cases in our institution from April 2020 to November 2021. We retrieved and retrospectively reviewed nine cases (two pediatric and seven adults) that experienced nephrotic syndrome (six cases), acute kidney injury (two cases), and a clinically silent microhematuria and leukocyturia. Kidney biopsies were investigated by means of light microscopy, direct immunofluorescence, and electron microscopy. The primary diagnoses were minimal change disease (four cases), acute tubular necrosis (two cases), collapsing glomerulopathy (two cases), and C3 glomerulopathy (one case). None of the cases showed viral or viral-like particles on ultrastructural analysis. Novel and specific histologic features on kidney biopsy related to SARS-CoV-2 infection have been gradually disclosed and reported, harboring relevant clinical and therapeutic implications. Recognizing and properly diagnosing renal involvement in patients experiencing COVID-19 could be challenging (due to the lack of direct proof of viral infection, e.g., viral particles) and requires a proper integration of clinical and pathological data.

Immunohistochemical typing of amyloid in fixed paraffin-embedded samples by an automatic procedure: Comparison with immunofluorescence data on fresh-frozen tissue.

Amyloidosis comprises a spectrum of disorders characterized by the extracellular deposition of amorphous material, originating from an abnormal serum protein. The typing of amyloid into its many variants represents a pivotal step for a correct patient management. Several methods are currently used, including mass spectrometry, immunofluorescence, immunohistochemistry, and immunogold labeling. The aim of the present study was to investigate the accuracy and reliability of immunohistochemistry by means of a recently developed amyloid antibody panel applicable on fixed paraffin-embedded tissues in an automated platform. Patients with clinically and pathologically proven amyloidosis were divided into two cohorts: a pilot one, which included selected amyloidosis cases from 2009 to 2018, and a retrospective one (comprising all consecutive amyloidosis cases analyzed between November 2018 and May 2020). The above-referred panel of antibodies for amyloid classification was tested in all cases using an automated immunohistochemistry platform. When fresh-frozen material was available, immunofluorescence was also performed. Among 130 patients, a total of 143 samples from different organs was investigated. They corresponded to 51 patients from the pilot cohort and 79 ones from the retrospective cohort. In 82 cases (63%), fresh-frozen tissue was tested by immunofluorescence, serving to define amyloid subtype only in 30 of them (36.6%). On the contrary, the automated immunohistochemistry procedure using the above-referred new antibodies allowed to establish the amyloid type in all 130 cases (100%). These included: ALλ (n = 60, 46.2%), ATTR (n = 29, 22.3%), AA (n = 19, 14.6%), ALκ (n = 18, 13.8%), ALys (n = 2, 1.5%), and Aß2M amyloidosis (n = 2, 1.5%). The present immunohistochemistry antibody panel represents a sensitive, reliable, fast, and low-cost method for amyloid typing. Since immunohistochemistry is available in most pathology laboratories, it may become the new gold standard for amyloidosis classification, either used alone or combined with mass spectrometry in selected cases.

Cervicogenic headache: a critical review of the current diagnostic criteria.

Opinions are divided on the use of the term cervicogenic headache (CGH) in cases with no evidence of cervical damage. According to Sjaastad et al. (1990), CGH is diagnosed from three features: (1) unilateral headache triggered by head/neck movements or posture; (2) unilateral headache triggered by pressure on the neck; (3) unilateral headache spreading to the neck and the homolateral shoulder/arm. Other characteristics are not essential for CGH diagnosis, including pain improvement after greater occipital nerve (GON)/C2 block. However, other authors give different definitions of CGH, and this may explain why reported frequencies for this headache vary so widely. In this paper we critically review the major diagnostic criteria of Sjaastad et al. for CGH in the light of clinical studies conducted at our institute and other literature findings. In a study of 500 headaches we found only two patients with unilateral headache triggered by head/ neck movements or posture, and no cases of neck pressure-induced headache. No clear-cut criteria are given in the literature for differentiating CGH trigger points from myofascial trigger points. In another study of 440 primary headache patients we found that in the unilateral long-lasting headache group (64 migraines and 10 tension-type headaches), a pain involving the occiput/neck was present in 30 migraine and seven tension headache patients; thus, according to the CGH major criteria, 10% (30/307) of 'migraines' and 7% (7/96) of 'tension headaches' could be diagnosed as CGH. However, one cannot exclude that the association of unilateral pain with posterior irradiation is due to the high prevalence of migraine, tension-type headache and chronic neck pain. The relation between CGH and whip-lash injury has been put in doubt by a recent study which found no difference in headache frequency between trauma and control groups and reported no specific headache pattern in the trauma group. Other reports suggest that, when it occurs, CGH usually disappears within a year of whip-lash, throwing doubt on the appropriateness of surgery for post-traumatic CGH. The lack of specificity of GON/C2 block as a treatment for CGH adds further difficulties to the diagnosis of this headache. We conclude that, although neck structures play a role in the pathophysiology of some headaches, clinical patterns indicating a neck-headache relationship have still not been adequately defined. We believe that further rigorous studies are needed to definitively confirm the validity of CGH as a nosological entity.

Trigeminal autonomic cephalgia with periorbital ecchymosis, ocular hemorrhage, hypertension and behavioral alterations.

We describe a 38-year-old male in whom severe unilateral headache was associated with marked palpebral edema, periorbital ecchymosis, lacrimation, conjunctival injection, nasal congestion and rhinorrhea. A second, less severe headache form developed subsequently. The patient often presented severe labile hypertension and behavioral disturbances during the crises, and there was an episode of intra-ocular hemorrhage. General, neurological and ophthalmological examinations revealed nothing remarkable. We discuss possible pathogenetic mechanisms and the nosology of this case within the trigeminal autonomic cephalgias.

Physicochemical determinants in the cellular responses to nanostructured amorphous silicas.

Amorphous silicas, opposite to crystalline polymorphs, have been regarded so far as nonpathogenic, but few studies have addressed the toxicity of the wide array of amorphous silica forms. With the advent of nanotoxicology, there has been a rising concern about the safety of silica nanoparticles to be used in nanomedicine. Here, we report a study on the toxicity of amorphous nanostructured silicas obtained with two different preparation procedures (pyrolysis vs. precipitation), the pyrogenic in two very different particle sizes, in order to assess the role of size and origin on surface properties and on the cell damage, oxidative stress, and inflammatory response elicited in murine alveolar macrophages. A quartz dust was employed as positive control and monodispersed silica spheres as negative control. Pyrogenic silicas were remarkably more active than the precipitated one as to cytotoxicity, reactive oxygen species production, lipid peroxidation, nitric oxide synthesis, and production of tumor necrosis factor-α, when compared both per mass and per unit surface. Between the two pyrogenic silicas, the larger one was the more active. Silanols density is the major difference in surface composition among the three silicas, being much larger than the precipitated one as indicated by joint calorimetric and infrared spectroscopy analysis. We assume here that full hydroxylation of a silica surface, with consequent stable coverage by water molecules, reduces/inhibits toxic behavior. The preparation route appears thus determinant in yielding potentially toxic materials, although the smallest size does not always correspond to an increased toxicity.

Mitochondrial localization of vitamin D receptor in human platelets and differentiated megakaryocytes.

BACKGROUND: Like other steroid hormones, vitamin D elicits both transcriptional events and rapid non genomic effects. Vitamin D receptor (VDR) localization and mechanisms of VDR-triggered non genomic responses are still controversial. Although anticoagulant effects of vitamin D have been reported and VDR signalling has been characterized in monocytes and vascular cells, nothing is known about VDR expression and functions in human platelets, anucleated fragments of megakaryocytes which are known targets of other steroids. METHODOLOGY/PRINCIPAL FINDINGS: In this study we characterized the expression and cellular localization of VDR in human platelets and in a megakaryocyte lineage. Human platelets and their TPA-differentiated precursors expressed a classical 50 kDa VDR protein, which increased with megakaryocytes maturation. By biochemical fractionation studies we demonstrated the presence of the receptor in the soluble and mitochondrial compartment of human platelets, and the observation was confirmed by immunoelectron microscopy analysis. Similar localization was found in mature megakaryocytes, where besides its classical nuclear localization the receptor was evident as soluble and mitochondria resident protein. CONCLUSIONS: The results reported here suggest that megakaryocytopoiesis and platelet activation, which are calcium-dependent events, might be modulated by a mitochondrial non genomic activity of VDR. These data open challenging future studies on VDR physiological role in platelets and more generally in mitochondria.