Evidence of apoptosis in human primordial and primary follicles

BACKGROUND: Apoptosis may operate the 'selection' between follicles destined for atresia and follicles that will remain available for ovulation. The aim of this study is to assess the expression of apoptosis in quiescent follicles. METHODS: Ovarian cortex samples from women of reproductive age, fixed in formalin, were used for immunohistochemical and terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick end labelling (TUNEL) methods. In histological sections the follicles were classified as primordial, primary, secondary and antral. Follicle density was defined as the total number of follicles/0.5 cm(2) of ovarian cortical tissue. Mab DO-7 (anti-p53) and Mab 124 (anti-bcl-2) were used in the immunohistochemical study. RESULTS: TUNEL was positive in 23.4% of the primordial follicles, and in 23.2% of the primary follicles, both in oocytes and granulosa cells, whereas all secondary follicles were negative. Bcl-2 activity was expressed in 75% of secondary follicles. p53 was negative in all samples. CONCLUSIONS: Apoptosis could be the process responsible for atresia of quiescent follicles and hence depletion of the ovarian germ stockpile. Follicular cells expressing Bcl-2 may therefore be the viable cells that escape the apoptotic process. Negative p53 patterns may be a favourable prognostic finding showing genome integrity in the replicating follicular cells of women of reproductive age.     

Increased CD8+-T-Cell Expression and a Type 2 Cytokine Pattern during the Muscular Phase of Trichinella Infection in Humans

Cell-mediated immunity during the muscular phase of Trichinella infection in humans was studied. Cell proliferation, the phenotypic changes in the T-cell population, and expression and production of cytokines were examined by using peripheral blood mononuclear cells (PBMC) collected at different times postinfection from 10 individuals who had acquired Trichinella spiralis and five individuals who had acquired Trichinella britovi in two distinct outbreaks. T. spiralis and T. britovi crude worm extracts induced proliferation of PBMC from T. spiralis- and T. britovi-infected donors. Cytokine gene expression showed a predominant type 2 pattern for the entire period of infection studied, although gamma interferon (IFN-gamma) was expressed. Interleukin-2 (IL-2), IL-5, IL-10, and IFN-gamma production was found in PBMC of all donors. There was a good correspondence between the cytokine expression and production patterns. Changes in PBMC composition, with a trend toward an increase in CD8(+) lymphocyte counts, were observed.     

The human natural killer cell receptor for major histocompatibility complex class I molecules. Surface modulation of p58 molecules and their linkage to CD3 ζ chain,FcϵRI γ chain and the p56lck kinase

The natural killer cell (NK)-specific p58 surface molecules, recognized by the GL183 and EB6 monoclonal antibodies (mAb), have been shown to represent the putative NK receptor for HLA-C molecules. The interaction between p58 receptors and HLA-C results in inhibition of the NK-mediated target cell lysis. In this study, GL183^?EB6⁺ clones (Cw4-specific), after mAb-induced surface modulation of EB6 molecules, acquired the ability to lyse the Cw4^? C1R cells. In NK clones co-expressing both GL183 and EB6 molecules and unable to kill Cw3-protected target cells, the mAb-induced modulation of EB6 molecules resulted both in selective co-modulation of GL183 molecules and in the lysis of Cw3-transfected P815 murine cells. In line with the co-modulation experiments we also show that the GL183 and EB6 molecules can be co-immunoprecipitated from GL183⁺/EB6⁺ clones after cell lysis in the presence of digitonin. The p58 receptor also revealed an association with molecules belonging to the ζ family (i.e. CD3 ζ and Fc?RI γ chains). Two-dimensional diagonal gel analysis of the p58 complex immunoprecipitated from polyclonally activated p58⁺ NK cells indicated a preferential association with CD3 ζ chains either in the form of covalently linked ζ-γ homodimers or in the form of ζ-γ heterodimers, while γ-γ homodimers were detectable in low amounts. However, p58⁺ clones displaying a unique association with γ-γ homodimers could also be isolated. Probing the immunoprecipitated p58 complex with anti-p56^lck antibody also revealed an association with this member of the src family. In addition, mAb-mediated signaling of NK clones via p58 molecules induced increments of p58/p56^lck association. However, under the same experimental conditions that induced optimal in vivo tyrosine phosphorylation of the CD16-associated CD3 ζ chains, no tyrosine phosphorylation was detected in the p58-associated CD3 ζ, chains. In these in vivo experiments neither anti-CD16 nor anti-p58 mAb could induce tyrosine phosphorylation of the γ chains. Finally, the anti-p58-mediated inhibition of the NK cell triggering via CD16 molecules was not accompained by a down-regulation of the tyrosine phosphorylation of the CD16-associated CD3 ζ chains.     

Hypotonically induced calcium increase and regulatory volume decrease in newborn rat cardiomyocytes

 The effect of cell swelling on intracellular calcium concentration ([Ca²⁺]_i) was studied in newborn rat cardiomyocytes. Hypotonic cell swelling induced a fast and transient [Ca²⁺]_i increase (hypotonically induced calcium increase, HICI; 388±47 nM, n=14). HICI was not inhibited by cyclopiazonic acid (CPA), an inhibitor of sarcoplasmic Ca²⁺-ATPase, nor ryanodine (an inhibitor of calcium-induced calcium release), whereas it was abolished (11±19 nM, n=5) in the absence of external calcium. Thus, HICI appeared to depend exclusively on entry of external calcium. Gadolinium ion (Gd³⁺), a generic inhibitor of stretch-activated cation channels (SACs), was unable to affect HICI (353±79 nM, n=6). Similarly, HICI was unaffected by internal Na⁺ depletion and external Na⁺ omission. These results suggest that neither Gd³⁺-sensitive SACs nor Na⁺-Ca²⁺ exchange is responsible for HICI. Conversely, HICI was inhibited by diltiazem (42±4 nM, n=3) and by membrane predepolarization (40±18 nM, n=5), suggesting an involvement of L-type voltage-activated calciumchannels. Cardiomyocyte swelling was followed by a regulatory volume decrease (RVD). The putative role of HICI in volume regulation was studied by removal of external calcium. This procedure significantly slowed RVD but did not abolish it. In conclusion, newborn rat cardiomyocytes exhibit an external-calcium-dependent HICI which contributes partially to the RVD. Received: 15 December 1997 / Received after revision and accepted: 1 May 1998     

CD59 is physically and functionally associated with natural cytotoxicity receptors and activates human NK cell-mediated cytotoxicity

Triggering of cytotoxicity in human NK cells is induced by the combined engagement of several triggering receptors. These include primary receptors such as NKG2D and the natural cytotoxicity receptors (NCR) NKp30, NKp46 and NKp44, while other molecules, including 2B4, NTB-A and NKp80, function as co-receptors. As reported in the present study, during an attempt to identify novel NK receptors or co-receptors, we found that CD59 functions as a co-receptor in human NK cell activation; engagement of CD59 by specific mAb delivers triggering signals to human NK cells, resulting in enhancement of cytotoxicity. Similar to other NK co-receptors, the triggering function of CD59, a glycosylphosphatidylinositol (GPI)-linked protein, depends on the simultaneous engagement of primary receptors such as NCR. Accordingly, CD59-dependent triggering was virtually restricted to NK cells expressing high surface densities of NKp46, and mAb-mediated modulation of NKp46 resulted in markedly decreased responses to anti-CD59 mAb. Biochemical analysis revealed that CD59 is physically associated with NKp46 and NKp30. Moreover, engagement of CD59 resulted in tyrosine phosphorylation of CD3zeta chains associated with these NCR, but not those associated with CD16. Thus, CD59-mediated costimulation of NK cells requires direct physical interaction of this GPI-linked protein with primary triggering NK receptors.     

Biological fate of tissue-engineered porcine valvular conduits xenotransplanted in the sheep thoracic aorta

The ideal prosthesis to replace the diseased human aortic valve is not yet available. We have previously shown that porcine acellular aortic-valve conduits, obtained by detergent-enzymatic method, display hemodynamic performances similar to those of their native counterparts. Hence, it seemed worthwhile to ascertain whether these tissue-engineered prostheses can be successfully xenotransplanted. Porcine acellular conduits, which immunocytochemistry demonstrated to lack MHC class I and II antigens, were implanted in the thoracic aorta of 9 sheep. Two animals died just after surgery, and the other 7 sheep were sacrificed 1 or 5 months after transplantation. A rather favorable outcome of the implant was observed in 4 sheep. In these animals, aortic valves remained pliable and coaptive, and the luminal surface of the conduits was endothelized just after one month from surgery. An intense inflammatory response was present at 1 month, and, although attennuated, it persisted for 5 months, located mainly between the tunica intima and media and at the border of the implant. Vimentin-positive and smooth muscle actin-positive myofibroblasts proliferated within tunica media and adventitia, and an obvious thickening of the tunica intima was also observed. Small vessels were seen in the adventitia, and elastic fibers were well-preserved in both the aorta wall and valve leaflets. In the cases of unfavorable outcome (3 of 7 survived sheep), implants were detached from the aorta recipient and surrounded by a connective mass that almost completely obstructed their lumen. These masses were composed of a fibromyxoid background where proliferating cells, resembling those occurring in human reactive myofibroblastic lesions (proliferative fascitis), were embedded. Collectively, these rather disappointing findings indicate that acellular valve conduits, obtained by the detergent-enzymatic method, are presently not suitable for clinical applications because of the persistent inflammatory response, which conceivably triggers overgrowth mechanisms that lead to implant failure.     

Limb body wall complex: A critical review and a nosological proposal

The analysis of the literature on limb body wall complex reveals a varied and rather confused spectrum of cases. However, we noticed the presence of at least 2 clearly distinguishable phenotypes. The first phenotype shows craniofacial defects and amniotic bands and/or adhesion; the second—without craniofacial defects—presents urogeniatal anomalies, anal atresia, and abdominal placental attachment, together with a persistence of the extra-embryonic coelom. We think these 2 phenotypes are the consequence of different pathogenetic mechanisms. The pathogenesis of the first type can be related to an early vascular disruption, while the pathogenesis of the second one is attributable to an intrinsic embryonal maldevelopment. Eight cases of the second phenotype were identified and the pathological findings proving this maldevelopmental origin are described. © 1993 Wiley-Liss, Inc.     

Guided vs. non-guided insertion of Ambu AuraGain™ in edentulous patients

Die Anaesthesiologie - Supraglottic airway devices perform more poorly and have lower oropharyngeal leak pressure in edentulous patients than in patients with teeth. The Ambu Aura Gain is...     

In vitro IL-6 production by EBV-immortalized B lymphocytes from young and elderly people genotyped for -174 C/G polymorphism in IL-6 gene: a model to study the genetic basis of inflamm-aging

In the present investigation we analysed Interleukin 6 (IL-6) in vitro production by Epstein-Barr virus (EBV)-immortalized B lymphocytes established from 43 subjects, 15 young people and 28 elderly people, including 18 centenarians, after 3, 6, 9, 24, 48 and 72 h of culture. The subjects were genotypized for the C to G transition at nucleotide -174 of IL-6 gene promoter (-174 C/G) and were classified as C allele carriers (C+) and non-carriers (C-). We found that: (i) the interindividual difference in in vitro IL-6 production was wider in elderly individuals in respect to young individuals, leading to different coefficient of variation in the two groups; (ii) the -174 C/G polymorphism had an age-related effect on IL-6 in vitro production. Only among C- people, cells from elderly subjects produced significant higher level of IL-6 than cells from young subjects. These data are consistent with our previous results regarding the IL-6 serum levels in a large group of people of different age, including centenarians. Thus, the EBV-immortalized B lymphocytes can be considered a useful in vitro model for studying the genetic control of IL-6 production and its changes with age.