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Biomedical subjects

M A Russo

Publications and source records attributed to M A Russo.

At least 55 records · Page 3Linked to original sources
PubMed1990

Selective binding of mouse and human spermatozoa to beads coated with extracellular matrix components.

The ability of mouse epididymal and human ejaculated spermatozoa to bind to beads coated with various extracellular matrix components was examined. Mouse spermatozoa preferentially bound to beads coated with heparin (average values ranging between 6.2 and 8.8 sperm per bead were obtained in different experiments) and with chondroitinsulfate (6.2-7.0), and also, although with significant differences across replicate experiments, to beads coated with laminin (7.9-15.6 sperm per bead) and with collagen type I (6.1-18.5). Human spermatozoa bound to collagen-coated beads (15.4-22.6 sperm per bead) and, to a much lower extent, to chondroitin-sulfate-coated beads (3.2-4.7); they were also able to bind heparin-coated beads, although with ample differences between individual sperm donors (ranging between 0.8 and 18.7 sperm per bead). Very few human and mouse sperm bound fibronectin-coated beads; beads coated with albumin, hyaluronic acid, and chondronectin were always totally free of adhering sperm. The possible physiological role of the interactions between spermatozoa and extracellular matrix components are discussed.

Amino Acid Sequence↗
PubMed1990

Subarachnoid clonidine reduces spinal cord blood flow and glucose utilization in conscious rats.

The authors investigated the spinal blood flow and metabolic effects of subarachnoid clonidine in conscious rats prepared with chronically implanted subarachnoid catheters. For the blood flow experiments, rats received saline (n = 7) or clonidine 20 nmol (7 micrograms; n = 6), 100 nmol (27 micrograms; n = 5), or 400 nmol (107 micrograms; n = 7) intrathecally. Another group of rats received clonidine 400 nmol intravenously (n = 4). Spinal glucose utilization was measured in rats that received either saline (n = 5) or clonidine 100 nmol (n = 5) intrathecally. Spinal cord blood flow (SCBF) and glucose utilization were measured in five gray and three white matter areas of lumbar spinal cord 15 min after drug administration with the autoradiographic iodo-[14C]-antipyrine and 2-[14C]-deoxyglucose methods, respectively. Physiologic differences between the groups were minor. Rats in the blood flow experiments that received clonidine 100 nmol had a slightly lower arterial PO2 level (70 +/- 1 vs. 82 +/- 3 mmHg; P less than 0.05), whereas those in the glucose utilization group were mildly hypocarbic (PCO2 27 +/- 1 vs. 32 +/- 2 mmHg; P less than 0.01) relative to control animals. Only animals that received 400 nmol clonidine intrathecally had significant analgesia, as assessed by the tail-flick test. One control animal for the metabolism experiments was technically unsatisfactory and was excluded from data analysis. Subarachnoid clonidine reduced both SCBF and glucose utilization. In spinal gray matter, the largest decreases in flow (32-44%; P less than 0.01) occurred with 20 nmol clonidine, whereas flow decreased least (12-27%) with the 400-nmol dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Modulation of phagocytic activity in cultured Sertoli cells.

Phagocytic activity of rat Sertoli cells that were cultured in vitro has been evaluated as the ability to internalize polystyrene beads. Our data demonstrate that these cells are active phagocytes and that such phagocytic activity is under negative control by follicle-stimulating hormone (FSH). The hormonal control is mediated by increased intracellular levels of cAMP. Moreover Sertoli cell responds to tuftsin, an oligopeptide known to act only on macrophages and granulocytes, by increasing up to five times its phagocytic activity. Phagocytic uptake of polystyrene beads is associated with dramatic changes of the cellular shape. Such morphological modifications are significantly reduced under FSH stimulation. The physiological implications of the data are discussed.

Animals↗
PubMed1988

Localization of lead in the kidney and liver of rats treated in vivo with lead acetate: ultrastructural studies on unstained sections.

The subcellular distribution and ultrastructural effects of lead have been studied in the kidneys and liver of rats given lead acetate (600 ppm Pb2+) in their drinking water for 6 months. Control rats were given sodium acetate. Tissue samples were fixed in glutaraldehyde and examined by electron microscopy with and without staining. Unstained sections of both kidney and liver from lead-treated animals showed small particles (2-5 nm diameter) of very high electron density which appear to represent a deposited form of Pb2+. Ultrastructural changes in the kidneys were largely confined to glomeruli (swelling of endothelial cells, fusion of foot processes, thickening of basement membrane) and proximal tubules (ranging from minimal sub-lethal changes to necrotic disorganization). The electron-dense particles of Pb2+ occurred in large clusters in basement membranes. As individual particles, or small groups, they were numerous in nuclei of proximal epithelium but usually only a few, largely confined to vesicles or inclusion bodies, were present in the cytoplasm. Only when cells were markedly damaged morphologically were particles more generally distributed in the cytoplasm. Liver damage by Pb2+ was largely confined to centrilobular regions. Endothelial and Kupffer cells were the most affected; they often sequestered large numbers of the particles. In parenchymal cells, particles were few and mainly in vesicles, but they were more widely distributed in the cytoplasm when morphological injury was apparent. The free distribution of Pb2+ in liver and kidney seems to be limited by its deposition in basement membranes and sequestration in reticulo-endothelial cells; intracellular distribution in healthy cells is also limited, by deposition in nuclei (in kidney only) or cytoplasmic vesicles.

Animals↗
PubMed1987

Anti-T cell monoclonal antibodies in vivo. II. Modulation of acute and chronic experimental allergic encephalomyelitis (EAE) in guinea pigs.

To determine the effects of anti-T cell monoclonal antibody-induced systemic T cell depletion in neuro-autoimmune disease, we studied the in vivo effects of 8BE6, a mouse anti-guinea pig (GP) pan-T cell monoclonal antibody, on the course and immunopathology of the disease model experimental allergic encephalomyelitis (EAE) in adult Strain 13 GP. Central nervous system (CNS) tissues were studied by routine histology and by an immunoperoxidase staining technique using monoclonal antibodies to T cells, IgM, and macrophages. From 3 days before to 10 days after sensitization with GP spinal cord and complete Freund's adjuvant, the GP were given one or two i.p. doses of 3.4 mg 8BE6 or MOPC 21, the parent mouse myeloma ascites, or normal saline. Eighteen of 18 control-treated GP developed typical acute, paralytic EAE 11 to 21 days after sensitization, whereas acute EAE was prevented in 33 of 49 8BE6-treated GP (67%), and the onset was delayed and disease progression was slowed in the others. Five GP treated with 8BE6 from days 11 to 14 after sensitization, at the onset of neurologic signs, rapidly deteriorated within hours after treatment and had loss of T cell staining, and lymphocytolysis in the CNS. 8BE6-treated GP which did not develop acute EAE were observed daily for up to 700 days (mean = 213 days). Twenty-nine of 39 (74%) had from one to six relapses or fixed neurologic deficits. GP in relapse were additionally treated with 8BE6 (22), MOPC-21 (5), or saline (6) in a cross-over protocol. Clinical scores were improved from days 2 to 12 after treatment (p less than 0.05), and complete recovery within 30 days occurred more frequently (p = 0.046) and more rapidly (p less than 0.01), after 8BE6 as compared with control treatments. Recoveries occurred more often if 8BE6 was given early in the relapse. Multiple treatments led to dose-dependent levels of serum antibodies to mouse immunoglobulin detected by an ELISA. There were no differences between acute and chronic EAE in numbers of inflammatory foci or numbers of macrophages and T cells in CNS infiltrates, but GP with chronic EAE had more extensive demyelination and vascular fibrosis and more numerous IgM+ B cells in parenchymal and meningeal infiltrates than in acute EAE (p less than 0.001).(ABSTRACT TRUNCATED AT 400 WORDS)

Acute Disease↗
PubMed1987

Membrane molecules involved in adhesion properties of cultured Sertoli cells.

Membrane components involved in adhesion properties of cultured Sertoli cells have been studied by a combination of immunological and biochemical methods. An antiserum prepared against Sertoli cells induced reversible rounding and detachment of the cells from the culture dishes. The cell surface morphology during detachment was studied by scanning electron microscopy and indirect immunofluorescence. A Triton soluble fraction of crude membrane preparations inhibited the antibody-induced detachment. The antibodies recognized a restricted number of membrane glycoproteins [detectable as prominent bands on Sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE), Mr 170, 140, 80, and 48K] both in the Triton soluble fraction of crude membrane preparation and on intact Sertoli cells. The data suggest that the molecules involved in adhesion properties of cultured Sertoli cells are integral membrane glycoproteins exposing antigenic determinants at the cell surface.

Animals↗
PubMed1987

Hormonal regulation of a chicken oviduct messenger ribonucleic acid that shares a common domain with gizzard myosin light chain kinase.

Changes in myosin light chain kinase (MLCK) and calmodulin (CaM) mRNAs have been evaluated during estrogen-mediated differentiation of the chicken oviduct. Also examined were acute changes that occur in oviduct RNA from animals stimulated with estrogen, withdrawn from hormone and then injected for 1, 2, and 4 days with synthetic estrogen [diethylstilbestrol (DES)], progesterone (P), or testosterone (T). Small changes were noted in both CaM and MLCK RNAs during primary stimulation when oviduct cells are actively dividing. On the other hand no significant changes were observed during secondary stimulation regardless of the steroid hormone injected. These data support the contention that CaM and MLCK are constitutively expressed but vary as a function of cell cycle. The MLCK mRNA is 5.5 kilobases (kb) but the MLCK cDNA also hybridizes to an oviduct RNA 2.7 kb long. This RNA species is acutely regulated by estrogen, P, and T but in a manner different from that of ovalbumin mRNA. The magnitude of stimulation of the 2.7 kb mRNA by diethylstilbestrol and T is greater than that of ovalbumin whereas changes in response to P are similar. The 12- to 16-fold increase of the 2.7 kb mRNA in response to T is the largest effect reported for this hormone acting on oviduct. The 2.7 kb mRNA encodes an unknown protein yet contains a 520 nucleotide segment that is highly homologous with the COOH-terminal coding portion of the MLCK mRNA. Since this homology does not include either catalytic or CaM-binding domains of MLCK, it is unlikely that the 2.7 kb mRNA encodes a CaM-dependent protein kinase.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Domain organization of chicken gizzard myosin light chain kinase deduced from a cloned cDNA.

Myosin light chain kinases (MLCK) are the most studied of the calmodulin-activated enzymes; however, minimal sequence information is available for the smooth muscle form of the enzyme. The production of an antibody against the enzyme and the use of expression vectors for constructing cDNA libraries have facilitated the isolation of a cDNA for this kinase. The derived amino sequence was found to contain a region of high homology (54%) to the rabbit skeletal muscle enzyme and also very significant homology (35%) to the catalytic subunit of phosphorylase b kinase and cGMP-dependent protein kinase. All of these homologies were found in the known catalytic domains of these enzyme, thus enabling us to predict the location of the catalytic domain for the chicken gizzard myosin light chain kinase. Within the catalytic domain a consensus sequence for an ATP-binding site was located. Subcloning and expression of different regions of the cDNA defined a 192 base pair fragment coding for the calmodulin-binding domain of MLCK. Both of the cAMP-dependent protein kinase phosphorylation sites were identified by sequence homology. A linear model for MLCK is presented placing the various domains in relative position. Northern blot analysis and S1 protection and mapping experiments have revealed that the mRNA for MLCK is 5.5 kilobases in length, but there also exists a second mRNA of 2.7 kilobases that shares a high degree of homology with about 520 base pairs at the 3' end of the cDNA for MLCK.

Amino Acid Sequence↗
PubMed1986

The basis for the cellular damage induced by ethacrynic acid in liver slices in vitro. Comparison of structure and function.

The development of cellular damage in response to ethacrynic acid and to amytal has been studied in slices of rat liver. After a preincubation at 1 degree C, the slices were incubated with or without the agents at 38 degrees C. Control slices showed a net extrusion of water, Na+, Cl-, and Ca2+, and a net reaccumulation of K+, during incubation at 38 degrees C. Ethacrynic acid (3 mM) reduced the extrusion of water, Na+ and Cl- during the first 5 minutes at 38 degrees C, but Ca2+ extrusion was not affected. Morphological indications of damage to mitochondria were apparent already at 5 minutes, although unaccompanied by a change of tissue ATP content. The mitochondrial damage was more marked at 15 minutes, when signs of early necrosis were also evident in some cells and ATP content started to fall. At longer times with ethacrynate, water and Ca2+ started to re-enter slices and there were indications of a loss of selective permeability of the plasma membranes; no significant uptake of K+ occurred at any time. Electron-dense particles, apparently of Ca2+, were deposited in the mitochondria and cisternae of the endoplasmic reticulum. The morphological appearance rapidly progressed to a marked disorganization. Slices incubated with 4 mM amytal showed greater and earlier loss of ATP than slices with ethacrynate and complete inhibition of water extrusion; other biochemical and morphological effects were generally less marked than with ethacrynate. Some of the morphological and biochemical effects of the two agents after 15 minutes at 38 degrees C could be reversed upon removal of the drugs. However, Ca2+ contents showed a late rise which started 20 minutes after removal of the drugs, indicating that an early, nonreversible damage of the calcium regulating mechanism had occurred. The results suggest that early effects of ethacrynate are on cell volume regulation and mitochondrial structure and function; there follow more general changes of membrane permeability and loss of control of cell Ca2+. A variety of biochemical and morphological markers of cell damage gave different indications of the level of damage in the early phases of treatment with each of the drugs used here. At longer times (e.g., 60 min) there was a greater degree of uniformity in the indications of cell damage.

Adenosine Triphosphate↗
PubMed1985

Morphological and physiological studies of rat kidney cortex slices undergoing isosmotic swelling and its reversal: a possible mechanism for ouabain-resistant control of cell volume.

Slices of rat kidney cortex were induced to swell by preincubation at 1 degree C in an isotonic Ringer's solution, and their capacity to reverse swelling, by net extrusion of cellular water, was studied during subsequent incubation at 25 degrees C. The recovery from swelling was prevented by the respiratory inhibitor, antimycin A. On the other hand, extrusion of water was little affected by ouabain. The extrusion of water continuing in the presence of ouabain (but not that in its absence) was significantly reduced when furosemide was added or when medium Cl- was replaced by NO-3 or I-. There was substantial variability in the morphological appearance of cells within the cortical slices. Different segments of the nephron showed different structural changes during swelling and its reversal, the proximal tubules being most markedly affected. Proximal tubular cells of swollen slices showed disorganization of brush borders and expansion of their apical surfaces, and contained vesicles in their apical cytoplasm. Upon recovery at 25 degrees C, the apical portions of these cells showed reversal of the expansion, but some apical vesicles remained. These vesicles were much more numerous after recovery in the presence of ouabain, but they were much reduced in numbers, or totally absent, when recovery took place in the presence of furosemide or absence of Cl-, with or without ouabain. The vesicles seen in the presence of ouabain alone appeared to fuse with each other and with infoldings of the basolateral plasma membrane. Rather similar results were obtained with distal tubular cells in the slices. We suggest that volume regulation in the proximal and distal tubular cells proceeds by way of two mechanisms. The first consists of extrusion of water coupled to the ouabain-sensitive transport of Na+ and K+. The other proceeds by way of an ouabain-resistant entry of water into apical cytoplasmic vesicles, following furosemide-sensitive movements of Cl- and Na+; the vesicles then expel their contents by exocytosis at the basolateral cell borders.

Animals↗
PubMed1984

Requirement of Cl- and Na+ for the ouabain-resistant control of cell volume in slices of rat liver.

The ability of liver cells to control their volume in the presence of ouabain has been studied in tissue slices that were recovering at 38 degrees C from a period of swelling at 1 degrees C. Morphological observations were made in conjunction with measurements of the net movement of water and ions. Extrusion of water in the presence of ouabain (2 mM) was accompanied by a net loss of Na+ and Cl- and by the formation of characteristic, rounded vesicles in the peri-canalicular regions of the hepatocytes; bile canaliculi were patent. When incubation was carried out in a medium in which either NO-3 or SO2-4 replaced Cl-, ouabain-resistant water extrusion was prevented and the cytoplasmic vesicles normally found with ouabain were almost totally absent. When these slices were subsequently transferred to Cl- medium with ouabain, extrusion of intracellular water was initiated and cytoplasmic vesicles reappeared. Replacement of medium Na+ by Li+ mimicked the effects of ouabain on water and ion movements and ultrastructure. In addition, the ouabain-resistant extrusion of water and Cl- was reduced and there was some diminution in the number of vesicles induced by ouabain. Furosemide (2 mM) had little effect on water movement or ultrastructure in the absence of ouabain, but it slowed the net water loss and substantially reduced the formation of cytoplasmic vesicles in the presence of ouabain. The results show a close relationship between ouabain-resistant water extrusion and the formation of the cytoplasmic vesicles that are characteristic of treatment with ouabain. They further suggest that a cotransport of Na+ and Cl- forms an important part of the mechanism underlying ouabain-resistant water extrusion and, specifically, that this cotransport may take place across the membranes of the cytoplasmic vesicles.

Animals↗
PubMed1983

Intercellular communication in rat seminiferous tubules.

Intercellular electrical coupling in seminiferous tubules from prepubescent and adult Wistar rats has been studied by using conventional techniques. It is found that cells in the seminiferous epithelium are electrically coupled. Experiments performed using "Sertoli cell-enriched" seminiferous tubules indicate the existence of intercellular ionic communication between Sertoli cells. Junctional conductance is independent of the direction of electrical field and it is affected by A23187 Ca ionophore (5 microM) but not by exposure to the neurotransmitter norepinephrine (1-5 X 10(-5) M). Intracellular resistivity (including junctional resistance) is higher in mature as compared to immature germinal epithelium. These findings suggest that cell metabolites or second messenger molecules could be transferred via the low-resistance pathways between epithelium cells to coordinate cellular activity.

Aging↗
PubMed1982

Ultrastruct pathology of phalloidin-intoxicated hepatocytes in the presence and absence of extracellular calcium.

The killing of cultured hepatocytes by phalloidin can be dissociated into two phases by manipulation of the Ca2+ concentration of the medium. In the absence of extracellular Ca2+, hepatocytes are injured but not killed by phalloidin. Addition of 1.8 mM Ca2+ to the culture medium kills 60-70% of the cells by three hours. As an initial attempt to identify the mechanisms whereby Ca2+ ions irreversibly injure phalloidin-damaged hepatocytes, we have examined the ultrastructural pathology of phalloidin-intoxicated liver cells in the presence or absence of extracellular Ca2+. In the absence of extracellular Ca2+ ions, the morphologic manifestations of phalloidin intoxication reflect entirely the interaction between phalloidin, microfilaments, and the plasma membrane. In the presence of Ca2+ ions, the morphologic manifestations of the lethal effects of Ca2+ are described: the swelling of mitochondria accompanied by the accumulation of dense, amorphous precipitates; a supercontracture of microfilaments, and a loss of volume control with intracellular edema and a change in cell shape. These alterations can be attributed to the known biologic actions of Ca2+ ions on cellular structure and function. The present study allows, therefore, a preliminary identification of mechanisms by which extracellular Ca2+ ions may mediate cell death in this as well as in other similar situations.

Animals↗