Intestinal immunity of dogfish Scyliorhinus canicula spiral valve: A histochemical, immunohistochemical and confocal study.

The present study describes histochemical and immunohistochemical characteristics of the spiral valve and its associated lymphoid tissue (GALT) in the dogfish Scyliorhinus canicula. The mucosal surface of the spiral valve represents the first line of defense against pathogens coming from the external environment through food. Epithelial, mucus and immune cells play a key role in controlling the inflammatory response. Valve intestine of S. canicula had many folds lined by simple columnar cells and goblet cells, which later reacted positive to PAS, AB and AB-PAS, histochemical stains differentiated the different types of mucins; lectin histochemistry (PNA and WGA), detected neutral and acid mucins secreted that plays an important role in protection against invading pathogens. Integrin α5ß1 was expressed in enterocytes that line the valve's folds with greater marking in the apical part of the cells. Laminin was found on the apical side of the epithelium, in fibrillar and cellular elements of the lamina propria and in the muscularis mucosa. In the spiral valve gut-associated lymphoid tissue (GALT) has been studied. For the first time, massive leucocytes aggregates were identified by confocal immunofluorescence techniques, using the following antibodies: TLR2, S100, Langerin/CD207. Our results expand knowledge about Dogfish valve intestine giving important news in understanding comparative immunology.

Expression of brain-derived neurotrophic factor and TrkB in the lateral line system of zebrafish during development.

The neuromasts of the lateral line system are regarded as a model to study the mechanisms of hearing, deafness, and ototoxicity. The neurotrophins (NTs), especially brain-derived neurotrophic factor (BDNF), and its signaling receptor TrkB are involved in the development and maintenance of neuromasts. To know the period in which the BDNF/TrkB complex has more effects in the neuromast biology, the age-related changes were studied. Normal zebrafish from 10 to 180 days post-fertilization (dpf), as well as transgenic ET4 zebrafish 10 and 20 dpf, was analyzed using qRT-PCR, western blot, and immunohistochemistry. BDNF and TrkB mRNAs followed a parallel course, peaking at 20 dpf, and thereafter progressively decreased. Specific immunoreactivity for BDNF and TrkB was found co-localized in all hairy cells of neuromasts in 20 and 30 dpf; then, the number of immunoreactive cells decreased, and by 180 dpf BDNF remains restricted to a subpopulation of hairy cells, and TrkB to a few number of sensory and non-sensory cells. At all ages examined, TrkB immunoreactivity was detected in sensory ganglia innervating the neuromasts. The present results demonstrate that there is a parallel time-related decline in the expression of BDNF and TrkB in zebrafish. Also, the patterns of cell expression suggest that autocrine/paracrine mechanisms for this NT system might occur within the neuromasts. Because TrkB in lateral line ganglia did not vary with age, their neurons are potentially capable to respond to BDNF during the entire lifespan of zebrafish.

Expression of ghrelin and leptin in the chemosensory system of adult zebrafish.

Numerous data show that the chemosensory system seems to be modulated by changes in the circulating levels of different molecules such as ghrelin, orexin, leptin, NPY, CCK. The chemosensory system of the zebrafish is represented by the taste buds (skin, oral and oropharyngeal), the olfactory rosette and the solitary chemosensorial cells (SCCs). The purpose of our study was to analyze the distribution of two peripheral hormones such as ghrelin and leptin in the chemosensory organs of the zebrafish. Our results demonstrated the presence of immunoreaction for all antibodies used in the zebrafish chemosensory organs even if with different distribution. In particular, IR was observed for ghrelin in the olfactory rosette while IR for leptin was found in the olfactory rosette, in the skin and oropharyngeal taste buds and in the gills. Both these hormones were detected in the intestine, used as a control.

Calretinin in the peripheral nervous system of the adult zebrafish.

Calretinin is a calcium-binding protein found widely distributed in the central nervous system and chemosensory cells of the teleosts, but its presence in the peripheral nervous system of fishes is unknown. In this study we used Western blot analysis and immunohistochemistry to investigate the occurrence and distribution of calretinin in the cranial nerve ganglia, dorsal root ganglia, sympathetic ganglia, and enteric nervous system of the adult zebrafish. By Western blotting a unique and specific protein band with an estimated molecular weight of around 30 kDa was detected, and it was identified as calretinin. Immunohistochemistry revealed that calretinin is selectively present in the cytoplasm of the neurons and never in the satellite glial cells. In both sensory and sympathetic ganglia the density of neurons that were immunolabelled, their size and morphology, as well as the intensity of immunostaining developed within the cytoplasm, were heterogeneous. In the enteric nervous system calretinin immunoreactivity was detected in a subset of enteric neurons as well as in a nerve fibre plexus localized inside the muscular layers. The present results demonstrate that in addition to the central nervous system, calretinin is also present in the peripheral nervous system of zebrafish, and contribute to completing the map of the distribution of this protein in the nervous system of teleosts.

Microcephalia with mandibular and dental dysplasia in adult Zmpste24-deficient mice.

ZMPSTE24 (also called FACE-1) is a zinc-metalloprotease involved in the post-translational processing of prelamin A to mature lamin A, a major component of the nuclear envelope. Mutations in the ZMPSTE24 gene or in that encoding its substrate prelamin A (LMNA) result in a series of human inherited diseases known collectively as laminopathies and showing regional or systemic manifestations (i.e. the Hutchinson-Gilford progeria syndrome). Typically, patients suffering some laminopathies show craniofacial or mandible anomalies, aberrant dentition or facial features characteristic of aged persons. To analyse whether Zmpste24(-/-) mice reproduce the cranial phenotype observed in humans due to mutations in ZMPSTE24 or LMNA, we conducted a craniometric study based on micro-computer tomography (microCT) images. Furthermore, using simple radiology, microCT, microCT-densitometry and scanning electron microscopy, we analysed the mandible and the teeth from Zmpste24(-/-) mice. Finally, the structure of the lower incisor was investigated using an H&E technique. The results demonstrate that Zmpste24(-/-) mice are microcephalic and show mandibular and dental dysplasia affecting only the mandible teeth. In all cases, the lower incisor of mice lacking Zmpste24 was smaller than in control animals, showed cylindrical morphology and a transverse fissure at the incisal edge, and the pulpal cavity was severely reduced. Structurally, the dental layers were normally arranged but cellular layers were disorganized. The inferior molars showed a reduced cusp size. Taken together, these data strongly suggest that Zmpste24(-/-) mice represent a good model to analyse the craniofacial and teeth malformations characteristic of lamin-related pathologies, and might contribute to a better understanding of the molecular events underlying these diseases.

Expression and distribution of S100 protein in the nervous system of the adult zebrafish (Danio rerio).

S100 proteins are EF-hand calcium-binding protein highly preserved during evolution present in both neuronal and non-neuronal tissues of the higher vertebrates. Data about the expression of S100 protein in fishes are scarce, and no data are available on zebrafish, a common model used in biology to study development but also human diseases. In this study, we have investigated the expression of S100 protein in the central nervous system of adult zebrafish using PCR, Western blot, and immunohistochemistry. The central nervous system of the adult zebrafish express S100 protein mRNA, and contain a protein of approximately 10 kDa identified as S100 protein. S100 protein immunoreactivity was detected widespread distributed in the central nervous system, labeling the cytoplasm of both neuronal and non-neuronal cells. In fact, S100 protein immunoreactivity was primarily found in glial and ependymal cells, whereas the only neurons displaying S100 immunoreactivity were the Purkinje's neurons of the cerebellar cortex and those forming the deep cerebellar nuclei. Outside the central nervous system, S100 protein immunoreactivity was observed in a subpopulation of sensory and sympathetic neurons, and it was absent from the enteric nervous system. The functional role of S100 protein in both neurons and non-neuronal cells of the zebrafish central nervous system remains to be elucidated, but present results might serve as baseline for future experimental studies using this teleost as a model.

Fine structure of the canal neuromasts of the lateral line system in the adult zebrafish.

The mechanosensory lateral line system of fish is responsible for several functions such as balance, hearing, and orientation in water flow and is formed by neuromast receptor organs distributed on head, trunk and tail. Superficial and canal neuromasts can be distinguished for localization and morphological differences. Several information is present regarding the superficial neuromasts of zebrafish and other teleosts especially during larval and juvenile stages, while not as numerous data are so far available about the ultrastructural characteristics of the canal neuromasts in adult zebrafish. Therefore, the aim of this study was to investigate by transmission electron microscopy the ultrastructural aspects of cells present in the canal neuromasts. Besides the typical cellular aspects of the neuromast, different cellular types of hair cells were observed that could be identified as developing hair cells during the physiological turnover. The knowledge of the observed cellular types of the canal neuromasts and their origin could give a contribution to studies carried out on adult zebrafish used as model in neurological and non-neurological damages, such as deafness and vestibular disorders.

Synthesis of bioinspired collagen/alginate/fibrin based hydrogels for soft tissue engineering.

Hydrogels based on natural polymers offer a range of properties to mimic the native extracellular matrix, and provide microenvironments to preserve cellular function and encourage tissue formation. A tri-component hydrogel using collagen, alginate and fibrin (CAF) was developed and investigated at three collagen concentrations for application as a functional extracellular matrix analogue. Physical-chemical characterization of CAF hydrogels demonstrated a thermo-responsive crosslinking capacity at physiological conditions with stiffness similar to native soft tissues. CAF hydrogels were also assessed for cytocompatibility using L929 murine fibroblasts, pancreatic MIN6 ß-cells and human mesenchymal stem cells (hMSCs); and demonstrated good cell viability, proliferation and metabolic activity after 7 days of in vitro culture. CAF hydrogels, especially with 2.5% w/v collagen, increased alkaline phosphatase production in hMSCs indicating potential for the promotion of osteogenic activity. Moreover, CAF hydrogels also increased metabolic activity of MIN6 ß-cells and promoted the reconstitution of spherical pseudoislets with sizes ranging between 50 and 150 µm at day 7, demonstrating potential in diabetic therapeutic applications.

Neuromast hair cells retain the capacity of regeneration during heavy metal exposure.

The neuromast is the morphological unit of the lateral line of fishes and is composed of a cluster of central sensory cells (hair cells) surrounded by support and mantle cells. Heavy metals exposure leads to disruption of hair cells within the neuromast. It is well known that the zebrafish has the ability to regenerate the hair cells after damage caused by toxicants. The process of regeneration depends on proliferation, differentiation and cellular migration of sensory and non-sensory progenitor cells. Therefore, our study was made in order to identify which cellular types are involved in the complex process of regeneration during heavy metals exposure. For this purpose, adult zebrafish were exposed to various heavy metals (Arsenic, cadmium and zinc) for 72h. After acute (24h) exposure, immunohistochemical localization of S100 (a specific marker for hair cells) in the neuromasts highlighted the hair cells loss. The immunoreaction for Sox2 (a specific marker for stem cells), at the same time, was observed in the support and mantle cells, after exposure to arsenic and cadmium, while only in the support cells after exposure to zinc. After chronic (72h) exposure the hair cells were regenerated, showing an immunoreaction for S100 protein. At the same exposure time to the three metals, a Sox2 immunoreaction was expressed in support and mantle cells. Our results showed for the first time the regenerative capacity of hair cells, not only after, but also during exposure to heavy metals, demonstrated by the presence of different stem cells that can diversify in hair cells.

Bone marrow failure may be caused by chromosome anomalies exerting effects on RUNX1T1 gene.

BACKGROUND: The majority of the cases of bone marrow failure syndromes/aplastic anaemias (BMFS/AA) are non-hereditary and considered idiopathic (80-85%). The peripheral blood picture is variable, with anaemia, neutropenia and/or thrombocytopenia, and the patients with idiopathic BMFS/AA may have a risk of transformation into a myelodysplastic syndrome (MDS) and/or an acute myeloid leukaemia (AML), as ascertained for all inherited BMFS. We already reported four patients with different forms of BMFS/AA with chromosome anomalies as primary etiologic event: the chromosome changes exerted an effect on specific genes, namely RUNX1, MPL, and FLI1, leading to the disease. RESULTS: We report two further patients with non-hereditary BM failure, with diagnosis of severe aplastic anaemia and pancytopenia caused by two different constitutional structural anomalies involving chromosome 8, and possibly leading to the disorder due to effects on the RUNX1T1 gene, which was hypo-expressed and hyper-expressed, respectively, in the two patients. The chromosome change was unbalanced in one patient, and balanced in the other one. CONCLUSIONS: We analyzed the sequence of events in the pathogenesis of the disease in the two patients, including a number of non-haematological signs present in the one with the unbalanced anomaly. We demonstrated that in these two patients the primary event causing BMFS/AA was the constitutional chromosome anomaly. If we take into account the cohort of 219 patients with a similar diagnosis in whom we made cytogenetic studies in the years 2003-2017, we conclude that cytogenetic investigations were instrumental to reach a diagnosis in 52 of them. We postulate that a chromosome change is the primary cause of BMFS/AA in a not negligible proportion of cases, as it was ascertained in 6 of these patients.

Melatonin treatment suppresses appetite genes and improves adipose tissue plasticity in diet-induced obese zebrafish.

PURPOSE: Overweight and obesity are important risk factors for diabetes, cardiovascular diseases, and premature death in modern society. Recently, numerous natural and synthetic compounds have been tested in diet-induced obese animal models, to counteract obesity. Melatonin is a circadian hormone, produced by pineal gland and extra-pineal sources, involved in processes which have in common a rhythmic expression. In teleost, it can control energy balance by activating or inhibiting appetite-related peptides. The study aims at testing effects of melatonin administration to control-fed and overfed zebrafish, in terms of expression levels of orexigenic (Ghrelin, orexin, NPY) and anorexigenic (leptin, POMC) genes expression and morphometry of visceral and subcutaneous fat depots. METHODS: Adult male zebrafish (n = 56) were divided into four dietary groups: control, overfed, control + melatonin, overfed + melatonin. The treatment lasted 5 weeks and BMI levels of every fish were measured each week. After this period fishes were sacrificed; morphological and morphometric studies have been carried out on histological sections of adipose tissue and adipocytes. Moreover, whole zebrafish brain and intestine were used for qRT-PCR. RESULTS: Our results demonstrate that melatonin supplementation may have an effect in mobilizing fat stores, in increasing basal metabolism and thus in preventing further excess fat accumulation. Melatonin stimulates the anorexigenic and inhibit the orexigenic signals. CONCLUSIONS: It seems that adequate melatonin treatment exerts anti-obesity protective effects, also in a diet-induced obesity zebrafish model, that might be the result of the restoration of many factors: the final endpoint reached is weight loss and stabilization of weight gain.

Localization of cholecystokinin in the zebrafish retina from larval to adult stage.

The peptide hormone cholecistokinin (CCK) plays a key role in the central and peripheral nervous system. It is known to be involved in the digestive physiology and in the regulation of food intake. Moreover, the CCK expression has also been detected in the retina of different vertebrates, including fish, although its biological activity in this tissue remains to be elucidated. In literature no data are yet available about the CCK-immunoreactivity in the zebrafish retina during development. Therefore, the aim of the study was to investigate the distribution of sulfated cholecystokinin octapeptide (CCK8-S) as a well preserved form during evolution in the zebrafish retina from 3days post hatching (dph) until adult stage, using immunohistochemistry in order to elucidate the potential role of this protein in the development and maintenance of normal retinal homeostasis. The cellular distribution of CCK in the retina was similar from 3 dph to 40days post fertilization (dpf) when immunoreactivity was found in the photoreceptors layer, in the outer plexiform layer, in the inner plexiform layer and, to a lesser extent, in the ganglion cell layer (GCL). Immunohistochemical localization at 50 dpf as well as in the adult stage was observed in a subpopulation of amacrine cells in the proximal inner nuclear layer, in the inner plexiform layer, in displaced amacrine cells and in retinal ganglion cells in the GCL. Our results demonstrate for the first time the occurrence of CCK in the zebrafish retina from larval to adult stage with a different pattern of distribution, suggesting different roles of CCK during retinal cells maturation.

The Tongue Dorsal Surface in Fish: A Comparison Among Three Farmed Species.

The oral cavity of vertebrates has a very important role in many functions strictly related to the food processing. Two species, sea bass Dicentrarchus labrax and seabream Sparus aurata, are mainly involved in the aquaculture industry in the mediterranean area; moreover, the white seabream Diplodus sargus sargus was recently chosen as the best candidate for the diversification of species of commercial interest. This investigation was carried out, using the standard procedures for light and scanning electron microscopy, to analyse the morphology of the tongue dorsal surface in order to show whether relationships are present between the tongue morphology and the nutritional choices of these species. In all the three investigated species, three different areas were observed on the dorsal lingual surface: an apex, a body and a root. In the sea bass D. labrax, numerous caninelike teeth, organized in pads, were present along the dorsal surface. The presence of numerous taste buds, scattered on the tongue, was shown. In the seabream S. aurata, the apical part of the tongue is inserted in a pouch with a characteristic medial ridge on the body surface. Numerous taste buds were scattered on the whole surface. In the white seabream D. sargus sargus, a pouch partially covering the apex was clearly observed. In the pouch, filiform-like and foliate-like papillae can be distinguished. The results show the important role of the fish tongue in the food ingestion process, demonstrating the interaction of food processing, taste and morphological characteristics.

Epidermal growth factor (EGF) expression in lateral line system and in taste buds of adult zebrafish (Brachidanio rerio).

The mechano and chemosensory organs of adult teleosts undergoes a continuous cell renewal and turnover which is regulated in part by growth factors. Here, we investigated the occurrence and the cell localization of epidermal growth factor (EGF) in the lateral line system and taste bud of adult zebrafish, using Western blot and immunohistochemistry associated to a polyclonal antibody against mammalian EGF. Furthermore, the distribution of S100 protein was studied in parallel to label hair sensory cells in the lateral line system. Western blot revealed one unique protein band with an estimated molecular weight of about 13 kDa, equivalent to the EGF of mammals. Specific immunoreactivity for EGF was observed in the epithelial basal and/or supporting cells of the neuromasts of the lateral line system and taste buds. Conversely, the sensory cells in both sensory structures were devoid of immunostaining. Present results demonstrate the occurrence of EGF in mechano and sensory system of adult zebrafish, suggesting a role for this molecule in the cell renewal and turnover of these structures.

Acid-sensing ion channels and transient-receptor potential ion channels in zebrafish taste buds.

Sensory information from the environment is required for life and survival, and it is detected by specialized cells which together make up the sensory system. The fish sensory system includes specialized organs that are able to detect mechanical and chemical stimuli. In particular, taste buds are small organs located on the tongue in terrestrial vertebrates that function in the perception of taste. In fish, taste buds occur on the lips, the flanks, and the caudal (tail) fins of some species and on the barbels of others. In fish taste receptor cells, different classes of ion channels have been detected which, like in mammals, presumably participate in the detection and/or transduction of chemical gustatory signals. However, since some of these ion channels are involved in the detection of additional sensory modalities, it can be hypothesized that taste cells sense stimuli other than those specific for taste. This mini-review summarizes current knowledge on the presence of transient-receptor potential (TRP) and acid-sensing (ASIC) ion channels in the taste buds of teleosts, especially adult zebrafish. Up to now ASIC4, TRPC2, TRPA1, TRPV1 and TRPV4 ion channels have been found in the sensory cells, while ASIC2 was detected in the nerves supplying the taste buds.

Predicting long-term functional results after myocardial revascularization in ischemic cardiomyopathy.

OBJECTIVE: The goal of the present study was to define the early and late functional results after revascularization in ischemic cardiomyopathy and to identify variables predictive of a favorable outcome. METHODS: A retrospective review of all consecutive patients with ischemic cardiomyopathy undergoing myocardial revascularization between January 1991 and June 1998 was undertaken. One hundred sixty-seven patients (140 men) aged 60 +/- 8 years (range, 39-77 years) with angina (n = 107), congestive heart failure (n = 54), or silent ischemia (n = 6) were identified. One hundred six (63%) patients with angina were in Canadian Cardiovascular Society class III or IV, and 40 (24%) patients with congestive failure were in New York Heart Association class III or IV. The preoperative left ventricular ejection fraction averaged 0.28 +/- 0.05 (range, 0.16-0. 30). Thirteen (8%) patients required preoperative mechanical life support. A mean of 2.9 +/- 0.9 grafts per patient were performed, with an average myocardial ischemia time of 53 +/- 23 minutes and bypass time of 104 +/- 31 minutes. RESULTS: There were 3 (1.7%) early deaths and 21 (13%) deaths during follow-up (2.7 +/- 2.1 years; range, 0.3-7.8 years), producing a survival of 94% +/- 2% and 75% +/- 10% at 1 and 5 years, respectively. Despite a significant increase in left ventricular ejection fraction (0.28 +/- 0.05 vs 0. 38 +/- 0.09, P =.0001), only 89 (54%) patients were symptom-free at follow-up. Freedom from recurrent angina was 98% +/- 1% and 81% +/- 8%, whereas freedom from congestive failure was 78% +/- 11% and 47% +/- 20% at 1 and 5 years, respectively. Follow-up New York Heart Association class in patients with congestive failure was improved (40/54 class III-IV vs 11/54 class III-IV, P =.0001). Multivariate analysis showed a lower ejection fraction (P =.01), preoperative congestive failure (P =.03), and a need for preoperative intra-aortic balloon pumping (P =.03) to be associated with a greater prevalence of recurrent congestive failure, whereas male sex (P =.01), preoperative angina (P =.04), use of the internal thoracic artery (P =.03), and higher number of grafts (P =.01) were associated with lower prevalence. Male sex (P =.06), higher number of grafts (P =.04), and shorter duration of myocardial ischemia (P =. 04) were also predictive of improvement in New York Heart Association class at follow-up. CONCLUSIONS: Despite satisfactory early and late survival, late functional outcome after myocardial revascularization in ischemic cardiomyopathy remains suboptimal because of recurrence or persistence of congestive failure. Selection of appropriate surgical candidates and extensive use of complete revascularization with the internal thoracic artery may substantially improve functional results.

Blood versus crystalloid cardioplegia for myocardial protection of donor hearts during transplantation: A prospective, randomized clinical trial.

OBJECTIVE: To assess the safety and efficacy of myocardial protection of the donor heart during transplantation with the use of blood cardioplegia, a prospective randomized clinical trial was undertaken between January 1997 and March 1998. METHODS: Forty-seven consecutive patients were assigned either to crystalloid (27 patients; group 1) or blood cardioplegia (20 patients; group 2). Comparison of recipient age (54 +/- 11 years vs 55 +/- 7 years; P =. 9), sex (89% vs 90% male patients; P =.9), diagnosis (63% vs 65% dilated cardiomyopathy; P =.8), elevated pulmonary vascular resistance (30% vs 30%; P =.9), prior cardiac operations (22% vs 30%; P =.5), need for urgent heart transplantation (7% vs 20%; P =. 2), donor age (32 +/- 11 years vs 31 +/- 13 years; P =.7), cause of death (33% vs 40% vascular; P =.5), and global myocardial ischemia (176 +/- 51 minutes vs 180 +/- 58 minutes; P =.5) showed no difference. Hemodynamically unstable donors (15% vs 45%; P =.02) were more prevalent in group 2. RESULTS: Operative mortality rates (4% vs 5%; P =.8), high-dose inotropic support (41% vs 30%; P = 0.6), and postoperative mechanical assistance (11% vs 10%; P = 0.9) were comparable in the 2 groups. Prevalence of acute right heart failure (27% vs 0; P =.02) and of temporary complete atrioventricular block (52% vs 20%; P =.02) were greater in group 1. Spontaneous sinus rhythm recovery was more prevalent in group 2 (11% vs 40%; P =.02). Higher peak creatine kinase (1429 +/- 725 u/L vs 868 +/- 466 u/L; P =.01) and creatine kinase MB (144 +/- 90 u/L vs 102 +/- 59 u/L; P =. 06) levels suggested more severe ischemic injury in group I. CONCLUSION: Use of blood cardioplegia was associated with a lower prevalence of right heart failure, cardiac rhythm dysfunction, and laboratory evidence of ischemia.

Hancock versus stentless bioprosthesis for aortic valve replacement in patients older than 75 years.

BACKGROUND: Stented aortic bioprostheses are routinely used in elderly patients. The stent, however, is obstructive and implies several hazards. Stentless aortic valves appear to be hemodynamically advantageous. However, their implantation is longer and technically more demanding, and durability is still under investigation. METHODS: Between January 1993 and December 1996, 77 patients (28 men) were prospectively randomized to undergo aortic valve replacement using the Hancock valves (group A: 40 patients, 16 men; age, 77+/-3 years; body surface area, 1.7+/-0.17 m2) or a stentless bioprostheses (group B: 37 patients, 12 men; age, 76+/-2 years; body surface area, 1.7+/-0.15 m2; Biocor, 17; Toronto SPV, 20). Preoperative variables were not significantly different between the two groups. Bypass time was 123+/-46 versus 133+/-51 minutes, and aortic cross-clamp time was 83+/-26 versus 95+/-24 minutes for group A and group B, respectively (not significant). Seven patients in group A (17.5%) and 5 in group B (13.5%) had enlargement of the aortic annulus. Valve size normalized to body surface area was 13.7+/-1.5 versus 14.1+/-1.6 mm/m2 for group A and group B, respectively (not significant). Eleven patients in group A (27.5%) and 5 in group B (13.5%) had concomitant myocardial revascularization. RESULTS: Overall perioperative mortality was 5% in group A (low cardiac output in 2 patients), and 8% in group B (low cardiac output in 1; major neurologic event in 2). Follow-up is 97% complete (group A, 14.5+/-10 months; group B, 18.5+/-12 months). One patient in group B died at 28 months of myocardial infarction. Actuarial survival at 12 and 24 months is 92% versus 91% and 92% versus 81% for group A and group B, respectively. At 6 months, patients in group A showed a peak transaortic gradient of 25+/-7 versus 20+/-9 mm Hg in group B. Progressive regression of left ventricular mass expressed as a percentage of preoperative value was 10.5% and 19% for group A and group B at 1 year postoperatively (not significant). CONCLUSIONS: Stentless valves represent a valuable alternative to conventional prostheses in patients older than 75 years, although no great advantages with their use emerge from this study. Continued evaluation particularly with regard to evidence of left ventricular remodeling and valve degeneration in the long term is warranted.

Preservation of the aortic valve in acute type A dissection complicated by aortic regurgitation.

BACKGROUND: The aim of the present study was to verify the efficacy of preserving the aortic valve in patients with acute type A aortic dissection complicated by significant aortic regurgitation. METHODS: From January 1979 to December 1996, 178 patients (125 males; mean age 57 +/- 9 years) underwent emergency surgery for acute type A aortic dissection, with an overall operative mortality rate of 21%. Based on a retrospective analysis of the preoperative angio- or echocardiographic findings, the 141 survivors were divided into 2 groups: Group 1 (G1) included 80 patients (57%) with no or mild aortic regurgitation, and Group 2 (G2) the remaining 61 patients with moderate-to-severe aortic regurgitation. The native aortic valve was preserved by means of a uniform technique consisting of reconstruction of the aortic root and sinotubular junction in 99 patients (70%) [68 in G1 (85%) and 31 in G2 (51%)]. Forty-two patients required aortic valve (8 patients; 6%) or total root replacement (34 patients; 24%). RESULTS: At a mean follow-up of 4 +/- 3.6 years (range, 6 months to 19 years), 19 of the 99 patients with a preserved aortic valve developed moderate-to-severe aortic insufficiency [19%; 7/68 in G1 (10%) and 12/31 in G2 (39%)]. Multivariate analysis revealed that moderate-to-severe preoperative aortic valve insufficiency was a significant risk factor for development of postoperative aortic valve regurgitation (p = 0.008). Reoperation was necessary in 7 G1 patients (10%) and in 8 G2 patients (26%), with an actuarial freedom from reoperation at 5 and 10 years of 93% +/- 7% and 80% +/- 9% in G1 patients, and 81% +/- 8% and 40% +/- 15% in G2 patients (p = 0.045). CONCLUSIONS: Preservation of the aortic valve and aortic root is recommended in patients with acute type A aortic dissection and absent or mild aortic insufficiency. Patients presenting with moderate-to-severe aortic regurgitation and treated conservatively present an increased risk of recurrent valvular insufficiency.

S100 protein-like immunoreactivity in the crypt olfactory neurons of the adult zebrafish.

The olfactory epithelium of some teleosts, including zebrafish, contains three types of olfactory sensory neurons. Because zebrafish has become an ideal model for the study of neurogenesis in the olfactory system, it is of capital importance the identification of specific markers for different neuronal populations. In this study we used immunohistochemistry to analyze the distribution of S100 protein-like in the adult zebrafish olfactory epithelium. Surprisingly, specific S100 protein-like immunostaining was detected exclusively in crypt neurons, whereas ciliated and microvillous neurons were not reactive, and the supporting glial cells as well. The pattern of immunostaining was exclusively cytoplasmic without apparent polarity within the soma, and the intensity of immunostaining was not related with the maturative stage of the neurons. The role of S100 protein in crypt olfactory neurons is unknown, although it is probably associated with the capacity of these cells to respond to chemical stimuli. In any case, it represents an excellent marker to identify crypt olfactory neurons in zebrafish.