Immunocytochemical detection of prostate-specific antigen (PSA) in skin adnexal and breast tissues and tumors

Prostate Specific Antigen (PSA) is regarded as a specific marker of prostatic epithelium and has never been detected by immunocytochemistry in extra-prostatic tissues. The casual finding of a strong positivity for polyclonal antisera to PSA in a sweat gland carcinoma prompted a study on a series of skin adnexial and breast specimens (normal and neoplastic). Normal axillary and perineal apocrine sweat glands, some apocrine foci in fibrocystic breast disease and two sweat gland and two breast apocrine carcinomas were stained by several PSA antisera; a recently introduced monoclonal to PSA, however, was unreactive. These observations cast doubt on the specificity of PSA for prostatic epithelium, especially when polyclonal antisera are employed. Immunocytochemical reactions obtained with PSA, in the investigation of skin, lesions must be interpreted with caution and confirmed if necessary with monoclonals to PSA and with PAP.     

Biogenesis of MalF and the MalFGK(2) maltose transport complex in Escherichia coli requires YidC

The polytopic inner membrane protein MalF is a constituent of the MalFGK(2) maltose transport complex in Escherichia coli. We have studied the biogenesis of MalF using a combination of in vivo and in vitro approaches. MalF is targeted via the SRP pathway to the Sec/YidC insertion site. Despite close proximity of nascent MalF to YidC during insertion, YidC is not required for the insertion of MalF into the membrane. However, YidC is required for the stability of MalF and the formation of the MalFGK(2) maltose transport complex. Our data indicate that YidC supports the folding of MalF into a stable conformation before it is incorporated into the maltose transport complex.     

Aldehyde-fuchsin staining of antral endocrine cells

Summary Correlative studies have been made to identify the endocrine cells stained by Aldehyde-Fuchsin (AF) in the cat and human antral mucosa.D-cells were weakly stained by AF after oxidation: this staining might be related to the disulphide group present in the molecule of Somatostatin (the hypothalamic hormone recently localized in D-cells).The gastrin-producing G-cells were on the contrary strongly stained (without oxidation) in tissues fixed in Helly-fluid. Histochemical investigations on the mechanism of such staining lead to the conclusion that it might be related to affinity of the stain for hidden acidic groups.     

Perturbation of Na+ and K+ gradients in human fibroblasts incubated in unsupplemented saline solutions

Changes in the intracellular concentrations of Na+ and K+ of fetal human fibroblasts have been followed after replacement of serum-containing growth media with unsupplemented and serum-supplemented saline solution (Earle's balanced salt solution). Incubation in unsupplemented salt solution was followed by a progressive increase of the internal Na+ counterbalanced by a decrease of internal K+, without major alterations of the internal osmolarity. After 3 h incubation the intracellular Na+ and K+ concentrations were 120 mM and 50 mM, respectively. These intracellular ion derangements were not associated with a failure of the (Na+ + K+)-ATPase pump, whose activity actually increased with enhanced intracellular Na+ concentration. Ion changes did not take place when serum (in excess of 0.5%, final concentration) was present in the saline solution and a complete restoration to normal of the Na+ and K+ gradients occurred upon addition of serum to cells previously incubated in plain saline solution. The effects of serum were mimicked by furosemide, thus suggesting that channels sensitive to this diuretic are involved in the movement of Na+ and K+ following fibroblast incubation in unsupplemented saline solution.     

Transport system ASC for neutral amino acids. An electroneutral sodium/amino acid cotransport sensitive to the membrane potential.

The influx of L-threonine through system ASC does not influence the membrane potential in cultured human fibroblasts although comparable fluxes of amino acids through another Na(+)-dependent agency, system A, effectively depolarize the cells. The membrane potential, however, stimulates the influx of amino acids through system ASC with a maximal effect at -50 mV. The sensitivity of amino acid influx through system ASC to the membrane potential is not constant, but rather, is dependent on intracellular and extracellular concentrations of the substrates, Na+ and amino acids, of the system. Conditions which favor the loading of the ASC carrier at the external surface reduce the sensitivity of ASC-mediated amino acid influx to the membrane potential; in contrast, the sensitivity of this amino acid influx increases under conditions which favor loading of the carrier at the internal surface. Trans-stimulation, a well-known characteristic of system ASC, also varies with the concentrations of the substrates of the system and, in fact, this characteristic is not observed when external Na+ is low. These data may be accommodated by a model in which an electrically silent mode of operation of the transporter is dominant. The influence of the membrane potential on the transport system is dependent on the extent to which a charge-translocating step in the cycling of the carrier is rate limiting (relative rate limitance).     

Comprehensive In Vitro Toxicity Testing of a Panel of Representative Oxide Nanomaterials: First Steps towards an Intelligent Testing Strategy

Nanomaterials (NMs) display many unique and useful physico-chemical properties. However, reliable approaches are needed for risk assessment of NMs. The present study was performed in the FP7-MARINA project, with the objective to identify and evaluate in vitro test methods for toxicity assessment in order to facilitate the development of an intelligent testing strategy (ITS). Six representative oxide NMs provided by the EC-JRC Nanomaterials Repository were tested in nine laboratories. The in vitro toxicity of NMs was evaluated in 12 cellular models representing 6 different target organs/systems (immune system, respiratory system, gastrointestinal system, reproductive organs, kidney and embryonic tissues). The toxicity assessment was conducted using 10 different assays for cytotoxicity, embryotoxicity, epithelial integrity, cytokine secretion and oxidative stress. Thorough physico-chemical characterization was performed for all tested NMs. Commercially relevant NMs with different physico-chemical properties were selected: two TiO₂ NMs with different surface chemistry – hydrophilic (NM-103) and hydrophobic (NM-104), two forms of ZnO – uncoated (NM-110) and coated with triethoxycapryl silane (NM-111) and two SiO₂ NMs produced by two different manufacturing techniques – precipitated (NM-200) and pyrogenic (NM-203). Cell specific toxicity effects of all NMs were observed; macrophages were the most sensitive cell type after short-term exposures (24-72h) (ZnO>SiO₂>TiO₂). Longer term exposure (7 to 21 days) significantly affected the cell barrier integrity in the presence of ZnO, but not TiO₂ and SiO₂, while the embryonic stem cell test (EST) classified the TiO₂ NMs as potentially ‘weak-embryotoxic’ and ZnO and SiO₂ NMs as ‘non-embryotoxic’. A hazard ranking could be established for the representative NMs tested (ZnO NM-110 > ZnO NM-111 > SiO₂ NM-203 > SiO₂ NM-200 > TiO₂ NM-104 > TiO₂ NM-103). This ranking was different in the case of embryonic tissues, for which TiO₂ displayed higher toxicity compared with ZnO and SiO₂. Importantly, the in vitro methodology applied could identify cell- and NM-specific responses, with a low variability observed between different test assays. Overall, this testing approach, based on a battery of cellular systems and test assays, complemented by an exhaustive physico-chemical characterization of NMs, could be deployed for the development of an ITS suitable for risk assessment of NMs. This study also provides a rich source of data for modeling of NM effects.     

Gelatinases (MMP2 and MMP9) in swine antral follicle

Follicular growth is allowed by extracellular matrix remodeling and vascular network development. Since matrix metalloproteinases (MMPs) play a crucial role in both of these processes, the aim of the present study was to evaluate the expression of gelatinases MMP2 and MMP9 in swine ovarian follicle (theca and granulosa compartments) during its development. Moreover, we measured gelatinase activities into follicular fluids (FF). Our data demonstrate for the first time that MMP2 and MMP9 are expressed in swine ovarian follicle both in theca and granulosa layers; moreover we show that the expression of both gelatinases increases in theca while decreases in granulosa during follicle growth. Additionally, MMP2 activity has been detected in FF. The spatial pattern of expression of gelatinases in swine follicle suggests a differential role during physiological ovarian events.     

Telocytes are the common cell of origin of both PEComas and GISTs: an evidence-supported hypothesis

We advance the hypothesis that the telocyte might be the cell of origin of both PEComas (perivascular epithelioid cell tumours) and GISTs (gastro-intestinal and extra-gastrointestinal stromal tumours). The hypothesis is supported by data from the literature reporting that both PEComas and GISTs, as well as telocytes, share the expression of several markers. These data were supplemented by original immunohistochemical tests on selected series. Specifically: (1) Melanoma markers (Melan A, MiTF) typical of PEComas are expressed by a substantial fraction of GISTs. A fraction of GISTs was also found positive for CD63, a tetraspanin protein originally described in melanomas and marking exosomes. (2) c-KIT (CD117), proper of the vast majority of GISTs, can be expressed by PEComas (as well as by telocytes). (3) Markers described in telocytes (CD34, S-100, smooth muscle actin and vascular endothelial growth factor) have been reported as positive in cases of PEComas and GISTs. Telocytes show distinctive ultrastructural features with thin, extended, telopodes and are likely involved in inter-cellular signalling via paracrine secretion as well as by shed vesicles and exosomes. These cells have been described in many locations (cavitary and non-cavitary organs) and might display potentialities of a wide spectrum of differentiation (and function). In conclusion we propose that telocytes could be the common cells of origin for both PEComas and GISTs.