Embryological considerations on a case of coexistence of persistent left superior vena cava and partially left inferior vena cava

The persistent left superior vena cava (PLSVC) is the most common venous thoracic congenital anomaly. The PLSCV generally drains into the right atrium, which it reaches through a dilated coronary sinus. Its presence is usually unrecognized, until a venous approach is performed. Abnormalities of the inferior vena cava (IVC) are rare (0.2-0.3% of healthy subjects and 0.6-2% of patients with cardiovascular defects). A single left IVC (LIVC) is very rare (11.9% of all the abnormalities) [1]. To the best of our knowledge, the coexistence of PLSCV and LICV has not been previously described. We present a case of a 32-year-old woman on hemodialysis for more than 12 years. An angiography demonstrated both a normal right SVC and a PLSCV and a single IVC with a lower left course, an intermediate circumaortic ring and an upper normal right course. The double SVC can be consequent to the failed development of the anastomosis between the anterior cardinal veins and the patency of the caudal part of the left anterior cardinal vein forming the PLSCV. As to the partially LIVC, its iliac and subrenal parts can be the results of the persistence of the left supracardinal vein. The circumaortic venous ring might indicate that a persistent intersupracardinal anastomosis receiving the left and the right renal veins was maintained around the abdominal aorta [2], while the superior part represents the normal right subcardinal and hepatic derivatives. The existence of anomalies should be considered, as they can have important implications in invasive procedures such as venous catheter placement, and may represent a speculative bridge between clinicians and embryologists

Trehalose protects the corneal epithelium in alcohol delamination: a structural and ultrastructural study

During laser subepithelial keratomilieusis (LASEK) the corneal epithelium undergoes to peculiar morphological changes owing to the dilute alcohol used to facilitate its mechanical separation from the stroma. As it was shown that trehalose, a non-reducing disaccharide of glucose, protects corneal epithelial cells from drying [1] and is effective in the treatment of experimental [2] and of human dry eye [3], aim of the present work was to evaluate the advantages of a pretreatment with trehalose to improve the structural and ultrastructural features of the corneal epithelium. Twelve patients undergoing LASEK were consecutively included in the study and treated as follows: topical anesthesia with oxybuprocaine hydrochloride 0.4 %, 20% ethanol in distilled water for 25 seconds followed by Merocel wetting, treatment with hypotonic BSS in distilled water, lifting of the epithelial flap with a beaver blade, excimer laser treatment (0.8 mm flying spot), reposition of the epithelial flap, BSS wash of the entire surface, application of a contact lens for 5-7 days. The right eyes of each patient were pretreated, together with the anesthetic, with 3% trehalose eye drops, whilst the left eyes were used as controls. Small parts of the epithelium were collected with a forceps at the end of the epithelial reposition and were processed for light and transmission electron microscopy. From the micrographs obtained with both techniques a morphometric analysis was also performed. In the controls, the corneal epithelium showed flat superficial cells with well-preserved apical microfolds, wing cells with intracellular vesicles and slightly dilated intercellular spaces, and irregularly shaped basal cells filled with vesicle, separated by wide spaces. In the trehalose-treated epithelium superficial cells showed normal shape, regular apical microfolds and well-preserved intercellular borders; wing cells had a well evident cytoskeleton, sometimes apparently double nuclei and normal intercellular borders, glued by desmosomes. The basal cells demonstrated polygonal shape, round nuclei and evident intracytoplasmic vesicles. The morphometric analysis carried out on the height and on the number of the layers of the corneal epithelium demonstrated in the trehalose-treated group values significantly lower than the control group. Similarly, basal hemidesmosomes were more numerous in the trehalose-treated group when compared to the control group. The morphological changes of the corneal epithelium during LASEK represent a simple and reproducible experimental model to evaluate the antagonists of an acute stress, such as the alcohol delamination. Our results demonstrate that trehalose administration before LASEK is able to maintain better morphological and morphometric features when compared to the control cornea

Corneal Structural Changes in Nonneoplastic and Neoplastic Monoclonal Gammopathies

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The human corneal epithelium after alcohol delamination: a structural and ultrastructural study

Dilute alcohol is one of the most popular methods for corneal epithelial removal during photorefractive keratectomy (PRK) and laser subepithelial keratomilieusis (LASEK). Even if the technique is used by nearly fifteen years, no concordant data are available on the effects of the exposition to dilute alcohol on the corneal epithelium. As in LASEK the epithelial flap obtained by the previous delamination is repositioned to improve corneal recovery, aim of the present work was to investigate the structure and the ultrastructure of the corneal epithelium after alcohol delamination. Ten patients undergoing PRK for myopic correction were consecutively included in the study. A 9-mm diameter cone was placed on the anaesthetized cornea and it was filled with 25% ethanol in BSS for 25 seconds. The cone was emptied and the corneal surface was washed off with BSS. The epithelial layer was lifted with beaver blade, peeled off with forceps, and processed for light (LM) and transmission electron microscopy (TEM). With LM, whilst superficial and wing cells showed a normal appearance, basal cells had significantly different staining patterns. In fact, in the same microscopic field they showed either normal morphology or paler nuclei and cytoplasm. When the specimens were observed with the TEM, all epithelial cells showed well-preserved intercellular spaces and junctional complexes. In the superficial cells perinuclear vacuolizations were present, whilst wing cells demonstrated no evident morphological changes. Clear basal cells had roundish nuclei with pale chromatin and clear cytoplasm with perinuclear endoplasmic reticulum and mitochondria and a large number of tonofilaments. Their basal membrane was generally intact, with many hemidesmosomes adhering to the basement membrane, which was formed only by the laminae lucida and densa. Dark basal cells showed irregular nuclei with condensed chromatin, vacuolated cytoplasm and few basal hemidesmosomes. Alcohol debridement can be considered as a valuable technique for removing corneal epithelium before PRK or for preparing an epithelial flap before LASEK: in fact it affects the binding of hemidesmosomes to the underlying basement membrane so that the lamina densa is separated from the lamina fibroreticularis. However, the observation of structural and ultrastructural changes of the basal cells, similar to those demonstrated in epithelial flaps obtained with the epikeratome, indicates the need for further studies to evaluate the corneal toxicity of the ethanol

The cornea in mucopolysaccharidosis IH-S: structural and ultrastructural study

Type I mucopolysaccharidoses (MPS I) include three autosomal recessive disorders (Hurler, MPS IH; Scheie, MPS IS; and Hurler-Scheie, MPS IH-S) caused by the deficient activity of the lysosomal hydrolase α-L-iduronidase with the consequent accumulation of dermatan and heparan sulfate in the lysosomes of several cell types [1]. MPS IH-S is an attenuated disease and the patients show minor facial and skeletal dysmorphism, regular intelligence, mild cardiac and respiratory disease, hepatosplenomegaly, and a normal lifespan. The most common feature is corneal opacification [2], whose morphological basis was not studied in detail. In this work we performed a structural and ultrastructural analysis of the cornea in a patient with MPS IH-S. The patient underwent penetrating keratoplasty and the corneal button was immediately processed for light and electron microscopy. From the micrographs a morphometric analysis was also performed. The corneal epithelium showed superficial cells with few microfolds and evident intercellular spaces. The wing cell layer was formed either by cells with well-evident tonofilaments and small peripheral clear vesicles, or with bilobed nucleus and large paranuclear vesicles filled with granular material. The basal cells showed polygonal shape, with many small vesicles, placed generally in the supranuclear cytoplasm: the intercellular space was enlarged by granular material. The Bowman’s layer was either normal in thickness and structure, or thinner and formed by granular material of variable electron density. The stroma was formed by irregular lamellae of differently oriented collagen, by a large number of keratocytes filled with vesicles, and by intercellular granular material. The corneal endothelium showed degenerative changes. The morphometric analysis of the collagen fibrils diameter provided a mean diameter of 21.71±2.09 nm. Hemidesmosomes were less numerous in the basal cells when compared to the normal cornea. Stromal keratocytes were reduced in their number, particularly in the anterior stroma. Our data showed in MPS IH-S patient pronounced changes of the epithelium, of the Bowman’s layer and of the stroma, consistent with the corneal opacity. As the etiology of the disease is a deficiency of α-L-iduronidase and the consequent accumulation of glycosaminoglycans, we are of the opinion that the stromal keratocytes are the first cells to be involved in the pathogenesis of the corneal disease. The accumulation of the aberrant products seems able to induce morphological changes of both the Bowman’s layer and the corneal epithelium

Role of NLRP3 in an experimental model of testicular ischemia and reperfusion in mice

Inflammasomes are multi-protein complexes composed of one of several leucinerich repeat receptors (NLRs) including NLRP1, NLRP3, NLRC4 and AIM2: NLRP3 is currently the most fully characterized inflammasome. Testicular torsion leads to tissue degeneration and, after reperfusion, results in production of reactive oxygen species and triggers the apoptosis machinery. To better understand the role of NLRP3 during testicular ischemia/reperfusion (TI/R), we investigated the morphological aspects of spermatogenesis underlying the effects of inflammasome in KO mice during TI/R. KO (Nlrp3tm1bhk) and wild-type (WT: C57Bl6) animals underwent 1h testicular-ischemia followed by reperfusion. The mice were killed after 1 day and 7 days of reperfusion and the determination of caspase-3 activity was executed. Furthermore, both the tubular (mean seminiferous tubule diameter and Johnsen’s scoring system [1]) and extratubular (edema, hemorrhagic extravasation, vessels dilation, and Leydig cells changes [2]) compartments were evaluated. The TUNEL assay for apoptosis was also performed. After 1 and 7 days of reperfusion in WT mice an increase of caspase-3 was observed. Structurally, marked histological damages characterized by altered spermatogenesis, evident extratubular changes and increased TUNEL activity were observed. In KO mice caspase-3 was inhibited. Histological damages were significantly decreased, TUNEL activity was reduced and extratubular changes were significantly milder. We suggest that NLRP3 inhibition might have a protective role on spermatogenesis and it can be proposed in patients with unilateral testicular torsion

Flavocoxid mitigates cadmium-induced toxicity: structural, immunohistochemical and molecular analysis in mice kidney

Background: Cadmium (Cd), a diffused environmental pollutant, has adverse effects on urinary apparatus [1]. The role of flavocoxid, a flavonoid with antioxidant activity [2], on the morphological and biochemical changes induced in vivo by Cd in mice kidneys was evaluated. Methods: C57 BL/6J mice received 0.9% NaCl alone, flavocoxid (20 mg/kg/day i.p.) alone, Cd chloride (CdCl2) (2 mg/kg i.p.) alone, or CdCl2 plus Flavocoxid (2 mg/kg i.p. plus 20 mg/kg/day i.p.) for 14 days. At the end of experiment, the mice were killed with an overdose of ketamine and xylazine and the kidneys were collected and processed for structural, immunohistochemical and biochemical analysis. Results: Cd treatment alone significantly increased iNOS, TNF-α and MMP-9 expression, induced structural damages in the glomeruli and in the proximal tubule epithelium, and reduced claudin-11, occludin and N-cadherin immunoreactivity. Flavocoxid administration reduced iNOS, TNF-α and MMP-9 expression, ameliorated glomerular and tubular changes and enhanced claudin-11, occludin and N-cadherin immunoreactivity. Conclusions: We demonstrated for the first time that flavocoxid has a protective role against Cd-induced damages in mice kidney. Therefore, flavocoxid may have a promising role against environmental Cd, in particular against its harmful effects on glomerular and tubular lesions

Structural, ultrastructural and morphometric study of the zebrafish cornea: a model for human corneal diseases?

The structural and ultrastructural organization of the ocular surface of Vertebrates is still partial and often controversial. A morphological and morphometric study of the adult zebrafish (Danio rerio) cornea was performed to provide a comprehensive description of its layers and to compare its organization to the human cornea [1,2]. The eyes of adult zebrafish were processed for light, transmission and scanning electron microscopy and a morphometric analysis was performed on several morphological parameters. The zebrafish cornea is thinner in its central part, while it is thicker in its periphery. Only four layers are present, as no Descemet membrane can be demonstrated. The epithelium is formed by 5-8 layers of polygonal cells, identified as superficial, intermediate and basal, and provided of an evident peripheral cytoskeleton. The Bowman layer is particularly thin (~ 250 nm) and is placed between the basal cells and the first stromal lamella. The stroma is formed by 26-40 lamellae of collagen fibers, among which only occasional keratocytes are present, generally in the posterior part. The endothelium is formed by a single layer of flat polygonal cells, 1-1.5 μm thick. The morphometric analysis showed mild differences between the central and the peripheral cornea; furthermore, the epithelium/stroma ratio is 0.89, while it is 0.09 in the human cornea. It can be concluded that, even if the general organization of the zebrafish cornea is similar to that of mammals, there are also several significant differences, such as the presence of a very thin Bowman layer, the reduced thickness of the stroma and the absence of the Descemet membrane. Therefore, caution is required when findings obtained from zebrafish as an experimental model are applied to normal or pathological corneas in other species, such as rodents or humans