Dilutional acidosis: a nonentity?
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Biomedical subjects
Publications and source records attributed to M A Russo.
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BACKGROUND: Permixon is a drug used in the treatment of benign prostatic hyperplasia. We studied its androgenic and antiandrogenic effects in the prostatic cell lines LNCaP and PC3, respectively responsive and unresponsive to androgen stimulation. METHODS: We performed FACScan analysis to investigate toxicity, 3H thymidine and 35S methionine incorporation to determine antiproliferative and metabolic effects, electron microscopy to study ultrastructural changes and cotransfection experiments to elucidate the role of wild type androgen receptor. RESULTS: In LNCaP cell line, Permixon induced a double proliferative/differentiative effect, not observed in PC3 cells. In PC3 cells cotransfected with wild-type androgen receptors and CAT reporter genes under the control of a androgen responsive element, the drug inhibited androgen-induced CAT transcription. CONCLUSIONS: Our data indicate a role of the androgen receptor in mediating the effects of Permixon in LNCaP cells. Cotransfection experiments in PC3 cells support a clear antiandrogenic action of the drug.
The relationship between nonverbal behavior and emotional awareness, as measured by the Toronto Alexithymia Scale, was studied in 24 young volunteers free of medical and psychiatric disorders. Multiple regression analysis revealed that nonverbal behavior during psychiatric interview was a significant predictor of the Toronto Alexithymia Scale total score independent of situational depression and anxiety. Subjects who had difficulty identifying and describing their feelings showed a combination of poor nonverbal expressivity and frequent self-directed behavior patterns indicative of tension and anxiety. In addition, subjects with a tendency toward externally oriented thinking showed more avoidance behavior during the interview. The ethological data of this study support clinical observations, which suggest that alexithymic traits interfere with both processing of emotion and interpersonal behavior.
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Nerve growth factor (NGF) and the other members of the family of neurotrophic factors (the neurotrophin) are essential for neuronal development and differentiation. Neurotrophins interact with two types of cell surface receptors: a low-affinity receptor (p75 NGF-R) and a high-affinity tyrosine kinase receptor belonging to the trk proto-oncogene family, both expressed in the nervous system and in certain non-neuronal tissues. Recently, NGF immunoreactivity and mRNA have been detected in the testis of the adult mouse, rat and human. In the present report we demonstrate the expression of p75 NGF-R during early gonadal development, by mesenchymal cells of the embryonic mouse and rat testis. In the embryonic testis p75 NGF-R-positive cells are spread through the interstitial compartment; during postnatal development they become organized in a cellular layer that surrounds differentiating myoid cells of the seminiferous tubule. Our results also show the expression in the peripuberal and adult mouse and rat testis, of an abundant and shorter transcript of 3.2 kb that cross-hybridizes to the receptor mRNA (3.7 kb). This new mRNA species, which appears at the beginning of spermatogenesis, is expressed by pachytene spermatocytes and round spermatids.
We have described previously three mouse multifinger coding genes (C. Passananti et al., Proc. Natl. Acad. Sci. USA, 86: 9417-9421, 1989). We have analyzed the expression of one of them, termed Mfg2 and renamed Zfp59, and demonstrated that Zfp59 mRNA and its translation product are present in specific stages of mouse spermatogenesis. The predicted amino acid sequence of the Zfp59 protein has been found to consist of 16 zinc-finger motifs clustered at the COOH terminus and subdivided into two groups by a degenerate finger motif. At its NH2 terminus, Zfp59 shares with other members of the zinc finger gene family two additional conserved amino acid modules A and B, described as either FAX, KRAB, or FPB domains. By means of Northern blot, Western blot analysis, and immunohistochemical localization, Zfp59 mRNA and its translation product were shown to be synthesized specifically during the postmeiotic phase of male germ line differentiation. By immunoelectron microscopy, the Zfp59 protein has been shown to accumulate in the nuclei of mature sperms in association with the nuclear matrix.
Nerve growth factor (NGF) is essential for neuronal development and differentiation. Recent reports have shown that its low-affinity receptor (LNGFR) is expressed and developmentally regulated in a broad range of embryonic and adult tissues outside the nervous system, although the functions of the receptor in such tissues remain unknown. Recently, NGF and LNGFR have been detected in adult mouse, rat, and human testis. The results of the present work demonstrate that LNGFR is expressed much before the onset of spermatogenesis in both mouse and rat testis. In situ hybridization shows that the mRNA for LNGFR is expressed in the peritubular cells of the embryonic mouse testis. Immunohistochemical analysis of the rat testis shows LNGFR-expressing cells to be scattered in the intertubular compartment in the embryonic testis, and to become organized in a cellular layer that surrounds myoid cells of the seminiferous tubules during postnatal development. Furthermore, in peripuberal and adult mouse and rat testis we have identified the expression of an abundant and shorter mRNA of 3.2 kb that cross hybridizes to the low-affinity NGF receptor transcript (3.7 kb). This shorter mRNA species, which appears at the beginning of spermatogenesis in the adult, has been identified by in situ hybridization and by Northern blot with RNA isolated from homogeneous populations of meiotic germ cells to be expressed by pachytene spermatocytes and round spermatids. Our results suggest a complex developmental role for LNGFR during testicular morphogenesis and identify the expression, at specific stages of spermatogenesis, of a new germ cell-specific transcript homologous to the receptor RNA.
Rat hepatocytes in primary monolayer culture have been studied by a combination of physiological and morphological approaches under conditions affecting ion transport and cell volume. A concentration of ouabain completely inhibiting the coupled transport of Na+ and K+ had little effect on cell volume, as indicated by cell water content, but induced the formation of many vesicles in the cytoplasm. Apparent fusion of vesicles was often observed. By itself, replacement of medium Cl by NO3- had little effect on cell volume or morphology. However, when NO3- replaced Cl- in the presence of ouabain the cells swelled and the numbers and size of vesicles were much reduced. The vesicles accumulating in the presence of ouabain showed a yellow fluorescence after the cells were loaded with acridine orange, implying that the vesicular contents were acidic. Total fluid-phase endocytosis, determined by uptake of Lucifer yellow, was not affected by ouabain or the absence of Cl-. However, ouabain considerably retarded the subsequent release of Lucifer yellow; this suggests that the dye originally taken into endocytotic vesicles became diluted by mixing with contents of ouabain-induced vesicles, an explanation consistent with the vesicle fusion seen by electron microscopy. The Cl-free medium also retarded Lucifer yellow efflux, to the same extent as ouabain, and the effects of the two treatments were not additive. These observations are consistent with the activity in hepatocytes of an ouabain-resistant, Cl(-)-dependent mechanism for cell volume control. It is suggested that this depends on the accumulation of water into acidic vesicles, which is driven by the Cl(-)-coupled activity of the vacuolar ATPases of the organelles, followed by exocytotic expulsion of their contents.
Integrins are a family of cell surface receptors that mediate cell-cell and cell-matrix interactions in a variety of different cellular systems. Here we show that unfertilized mouse oocytes express beta 1 class integrins both at mRNA and protein levels. Using the reverse transcription polymerase chain reaction and oligonucleotide primers based on the DNA sequence of mouse integrins, the RNA transcripts for the beta 1, alpha 5 and alpha 6 subunits were detected in unfertilized oocytes. The expression of the mRNAs is paralleled by the expression of the corresponding proteins, in fact, the alpha 5/beta 1 and the alpha 6/beta 1 complexes can be immunoprecipitated with specific antibodies form 125I-surface-labeled oocytes. Using subunit-specific antibodies we also demonstrate the presence of the alpha 3/beta 1 at the oocyte surface but alpha 1, alpha 2, alpha 4 or alpha V subunits were not detectable. Since the mouse alpha 3 DNA sequence is not available, we have not tested for the corresponding transcript. Integrin subunits alpha 6 and beta 1 were differently distributed on the oocyte surface, as visualized by immunofluorescence staining and by immunoelectron microscopy. alpha 6 antigen was mainly confined to the microvillous area of the oocyte surface, while beta 1 was more homogeneously distributed over the whole oolemma. These data demonstrate for the first time the expression of three beta 1 integrin complexes in unfertilized mouse oocytes. Such proteins may have a role in sperm-egg interaction or during very early steps of embryogenesis.
An unusual case of severe dilated cardiomyopathy is described in a woman with postpartum hypopituitary function, which was characterized by marked decrease of cardiac myofibrils (decreased ratio of myofibrillar volume:cell volume) and somatomedin C deficiency. The patient was treated with a daily intramuscular dose of 4 UI of recombinant human growth hormone for 3 months. Clinical and laboratory assessment and follow-up consisted of noninvasive (echocardiograms, Doppler study, and clinical laboratory tests) and invasive procedures (angiography and endomyocardial biopsy). Morphologic study included optical and electron microscopic examinations and morphometric analysis. The patient exhibited a relevant improvement of cardiac function after recombinant human growth hormone administration. The clinical improvement was confirmed by normalization of electrocardiographic voltages, increased myocardial mass, angiography, and optical and electron microscopic examination, which showed a dramatic recovery of myofibrillar content in myocardiocytes. Furthermore, withdrawal of growth hormone was followed by reduction of electrocardiographic voltages and myocardial mass as well as by impairment of left ventricular function. The authors suggest that there are forms of dilated cardiomyopathy that may benefit dramatically by growth hormone administration. These forms should be identified by growth hormone/somatomedin C axis deficiency and by decrease in myofibrillar content at endomyocardial biopsy.
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When mouse spermatozoa were briefly exposed in culture to radioactively labelled DNA (pSV2CAT plasmid), radioactivity could be detected by high-resolution autoradiography on the surface and within the nucleus of the spermatozoa. Spermatozoa from other mammalian species (boar, bull, man) could also bind foreign DNA. With the exclusion of human spermatozoa, which in most experiments showed very low labelling values, labelling percentages (evaluated by light microscope autoradiography) ranged between 39 and 78%. In all four species the DNA-binding ability was mainly confined to a specific region of the sperm head (equatorial segment and postacrosomal region), and the sperm-DNA association kinetics were rapid (maximum values were reached within 20-40 min). The data also indicate that factor(s) in seminal plasma might protect spermatozoa from accidental transfection by foreign DNA that may be present in the genital tracts from bacterial or viral sources.
Slices of lungs from late-fetal (1 day pre-partum) and adult rats lost K+ and gained Na+, Cl-, water and Ca2+ during pre-incubation at 1 degrees C. These changes were reversed upon restoration to 37 degrees C. The recovery of composition at 37 degrees C was completely dependent on cell respiration in adult slices; by contrast, glycolysis could support partial recovery in the fetal slices. Ouabain completely inhibited K+ reaccumulation at both ages but inhibited net extrusion of water by no more than 50%. Replacement of medium Cl- with NO3- prevented the extrusion of water in the presence of ouabain in adult but not fetal slices. Transmission electron microscopy of type II epithelial cells in slices of both ages showed that ouabain induced the formation of many cytoplasmic vesicles, apparently derived from the Golgi apparatus. Regulation of cell ionic and water content is thus generally similar in late-fetal and adult lung tissue, but there are differences in the source of ATP and in some features of ouabain-resistant volume regulation.
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A catecholamine-induced dilated cardiomyopathy is reported in a patient with multiple endocrine neoplasia, type 3. A histologic and ultrastructural study has been undertaken in cardiac biopsy samples, together with determination of myocardial Ca++ and cellular membrane fatty acids. Contraction band necrosis of cardiocytes with supercontraction of sarcomeres progressing to myofibrolysis and increased levels of myocardial Ca++ have been found as morphologic and biochemical abnormalities, respectively. No lipoperoxidation of cellular membranes or an alpha-adrenergic mediated reduction of coronary supply could be recognized in the study. We indicate a receptor-mediated intracellular Ca++ overload as the main abnormality responsible for myocardial impairment.