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Biomedical subjects

S L Rogers

Publications and source records attributed to S L Rogers.

At least 55 records · Page 3Linked to original sources
PubMed1986

The Purdue Pegboard: norms for 14- to 19-year-olds.

The purpose of this study was to collect normative data on the Purdue Pegboard, a test of finger dexterity, for individuals aged 14 to 19 years. Three trials were administered to 176 subjects from the seven-county Milwaukee area. Results indicated that females performed better than males on three out of four subtests, suburban subjects scored better than urban subjects on two of four subtests, and scores increased with age. The normative data collected provide a means of comparing a patient's score with normal individuals of the same sex and age and aid in determining a patient's need for therapy and in setting appropriate treatment goals.

Adolescent↗
PubMed1986

Disposition of 8-methoxypsoralen in the rat: methodology for measurement, dose-dependent pharmacokinetics, tissue distribution and identification of metabolites.

The pharmacokinetics and metabolism of 8-methoxypsoralen (8-MOP) were measured in the catheterized rat after a single i.v. dose. Blood samples were collected serially and analyzed using a sensitive and specific assay for [14C]-8-MOP. Total body clearance of 8-MOP was 7.3, 3.9, 1.7, 1.0, 0.78 and 0.42 liters/kg/hr at doses of 0.2, 1.0, 2.5, 5.0, 10 and 20 mg/kg, respectively. The decline in total body clearance indicates that elimination of 8-MOP is dose-dependent in the rat. After i.v. administration of 10 mg/kg of 8-MOP, 71 and 26% of the dose was recovered within 72 hr in the urine and feces, respectively. Unchanged 8-MOP accounted for less than 1% of the excreted radioactivity. In tissue distribution studies at 0.5, 2 and 5 hr after i.v. administration, 8-MOP distributed rapidly to all tissues and concentrated in the fat and kidneys. The concentration of 8-MOP in the skin was 0.4 to 0.6 times that in the blood. Eleven metabolites of 8-MOP were detected in the urine. The metabolites identified after enzymatic hydrolysis were 8-hydroxypsoralen; 5-hydroxy-8-methoxypsoralen; 5,8-dihydroxypsoralen; 5,8-dioxopsoralen; 6-(7-hydroxy-8-methoxycoumaryl)-acetic acid and 8-MOP (formed by ring closure of a coumaric acid metabolite). Thus, these studies indicate that 8-MOP is metabolized in the rat by 1) O-demethylation; 2) hydroxylation at position 5; 3) hydrolysis of the lactone ring and 4) oxidation of the furan ring, a pathway already confirmed in insects, dogs and humans.

Animals↗
PubMed1985

Fibronectin is an acute phase reactant in mice.

Tissue injury and inflammation are potent stimuli for the immediate increased synthesis of several plasma proteins collectively known as acute phase phase reactants. This dramatic phenomenon is thought to play an important role in inflammation and tissue repair. Plasma fibronectin is a normal plasma glycoprotein and a major non-specific opsonin apparently involved in maintaining the integrity of the mononuclear phagocytic system. Because of its ability to mediate clearance of intravascular particulate matter, increased production following tissue injury could be of benefit to the organism. We now report that plasma fibronectin is a significant acute phase reactant in mice with levels increasing from a baseline mean value of 257 ug/ml to 595 ug/ml by 24 hours (p less than 0.01) after a subcutaneous injection of silver nitrate. Similar findings were observed when subcutaneous casein was used as the acute phase stimulus. This data provides further circumstantial evidence that plasma fibronectin is involved in host defence and tissue repair.

Acute-Phase Proteins↗
PubMed1985

Neuron-specific interactions with two neurite-promoting fragments of fibronectin.

Proteolytic fragments of fibronectin were used to identify regions of the molecule that support neurite extension and to investigate further the differential behavior of central and peripheral nervous system neurons in response to fibronectin (Rogers, S. L., P. C. Letourneau, S. L. Palm, J. B. McCarthy, and L. T. Furcht (1983) Dev. Biol. 98: 212-220). Fibronectin fragments with differing biological activities were produced by proteolytic digestion with trypsin and cathepsin D and sequential affinity chromatography on gelatin-agarose and heparin-Sepharose. The resulting fragments (described by Smith, D. E., D. F. Mosher, R. B. Johnson, and L. T. Furcht (1982) J. Biol. Chem. 257: 5831-5838; Smith, D. E., and L. T. Furcht (1982) J. Biol. Chem. 257: 6518-6523 included an NH2-terminal 27,000-dalton peptide that weakly binds heparin, a 46,000-dalton gelatin-binding fragment, a series of fragments (80,000 to 125,000 daltons) from the center of the molecule containing previously described cell-binding activity, two major peptides of Mr = 33,000 and 66,000 that bind heparin strongly and are thought to originate from the A and B chains, respectively, of plasma fibronectin, and a 31,000-dalton COOH-terminal peptide containing a free sulfhydryl from the A chain of the molecule. Tissue culture dishes were treated with these proteolytic preparations, and dissociated embryonic chick peripheral (PNS) and central nervous system (CNS) cells were cultured on each experimental substratum in serum-free medium. The fibronectin fragments were evaluated for ability to promote cell attachment, neurite initiation, and maintenance of neurite growth. The 27,000-, 46,000-, and 31,000-dalton preparations did not promote cell attachment or neurite extension. Both PNS and CNS neurons attached to and extended stable neurites upon the COOH-terminal heparin-binding preparation containing the 33,000- and 66,000-dalton peptides. A differential response of the neurons to the 80,000- to 125,000-dalton "cell-binding" peptides was observed: whereas PNS neurons maintained neuritic growth on this preparation for at least 48 hr, CNS neurons extended neurites during the first 24 hr of culture but, by 48 hr, withdrew these neurites and became increasingly clumped. On the basis of (1) the observed neuronal responses to the heparin binding and "cell binding" regions, and (2) the different ligand-binding properties of these regions, we propose that cell attachment and neurite extension can be mediated and/or modulated by two separate regions of fibronectin and that cellular response to the intact molecule may involve multivalent interactions.

Animals↗
PubMed1984

Serum levels of C-reactive protein in neonatal respiratory distress syndrome.

Serum levels of C-reactive protein (CRP) were measured within 96 hours of birth in 55 neonates with respiratory distress syndrome (RDS), 19 neonates with no significant medical illness other than an unstable cardiovascular state, and 13 neonates with a variety of pulmonary and extra-pulmonary problems either alone or in combination with RDS. The median serum CRP level in patients with RDS (2 micrograms/ml) was neither elevated nor different from CRP levels in infants with unstable cardiovascular systems (median CRP level, 2 micrograms/ml); however, neonates with other problems including pneumonia, aspiration, and extrapulmonary sepsis had significantly elevated serum CRP values (median 24 micrograms/ml). CRP levels are not elevated in neonatal RDS. Measurement of this acute phase reactant provides a rapid and reliable means of helping to distinguish infants with uncomplicated RDS from those with other serious pulmonary and extrapulmonary disease.

C-Reactive Protein↗
PubMed1983

Neurite extension by peripheral and central nervous system neurons in response to substratum-bound fibronectin and laminin.

Dissociated neurons from embryonic chick dorsal root and sympathetic ganglia (peripheral neurons) and from spinal cord and retina (central nervous system neurons) were cultured on plastic substrata treated with purified fibronectin and laminin. Both central and peripheral neurons attached to and extended neurites on laminin. In contrast, only peripheral neurons initiated neurites on fibronectin; central neurons cultured under identical conditions aggregated into clusters and did not extend neurites. Neurite length, number of neurites initiated, and extent of neurite branching on fibronectin- and laminin-treated substrata were evaluated and compared with similar measurements of neuronal response to poly-L-lysine-treated plastic. Poly-L-lysine provides an adhesive surface for neurite elongation, but fibronectin and laminin appear to promote more rapid neurite elongation. Our observations suggest that neuronal interaction with these glycoproteins may involve neuron-specific cell surface components. These responses to laminin and fibronectin in vitro may be related to the presence or absence of these glycoproteins in specific extracellular environments during specific developmental stages.

Animals↗
PubMed1983

Stretch receptors in regenerated rat muscle.

Although muscle spindles are known to be present in regenerated muscles, it has not previously been reported whether they have any electrophysiological activity. In the present study, rat extensor digitorum longus muscles were traumatized so as to cause all muscle fibers to degenerate; the muscle nerves were either left intact to promote subsequent reinnervation or severed to impede reinnervation. After 2-4 months of regeneration, the muscles were subjected to stretch stimuli and sensory activity was recorded electrophysiologically. Many of the muscles contained stretch-sensitive units that behaved like muscle spindles, although the responses were often highly adaptive and somewhat erratic. In general, the responses from muscles with the nerve left intact were more normal than those from muscles in which the nerve had been severed. Silver staining of the same muscles showed that morphologically recognizable muscle spindles were present, but all were abnormal to varying degrees. These results demonstrate that regenerated muscles can regain some degree of sensory activity in addition to motor functions. The prospect of restored sensory activity may be critical in evaluating the efficacy of graft or transplant procedures for human muscles.

Animals↗
PubMed1982

Role of the acute phase response in the Shwartzman phenomenon.

Following elicitation of the local Shwartzman reaction by intradermal injection of Salmonella enteritidis lipopolysaccharide (LPS) in mice, there was a marked acute phase response which was monitored by measuring the serum levels of serum amyloid P component (SAP) and C3. Prednisolone therapy had no effect on either the cutaneous lesion or the accompanying acute phase response. Also, in vivo complement depletion with cobra factor did not affect the lesion or the SAP response despite gross reduction in serum C3 levels. In contrast, administration of colchicine at the same time as LPS suppressed both the acute phase response and the Shwartzman reaction. Inhibition of the cutaneous reaction by colchicine was abrogated by injecting mice with casein, and unrelated acute phase stimulus, the day before challenge with LPS. These observations suggest that acute phase proteins may participate in pathogenesis of the Shwartzman phenomenon.

Amyloid↗
PubMed1980

Complement-independence of the acute-phase production of serum amyloijd P-component (SAP) in mice.

Mice depleted of circulating C3 by injection of cobra factor (CoF), the C3-activating protein of cobra (Naja naja) venom, mounted the same acute-phase responses of serum amyloid P-component (SAP) to subsequent injection of casein, bacterial lipopolysaccharide or croton oil as did normal control mice. There was also evidence for accelerated synthesis of C3 itself in response to injection of these acute-phase stimulants in CoF-treated mice. On the other hand complement activation produced by injection of CoF alone did not cause any elevation of the serum SAP level. These results indicate that acute-phase plasma protein production can proceed independently of the complement system as a mediator of or participant in inflammatory reactions, and that complement activation alone is not a sufficient stimulus for an acute-phase response, at least of SAP.

Amyloid↗
PubMed1975

Regeneration of digits and forelimbs in the Kenyan reed frog Hyperolius viridiflavus ferniquei.

Newly metamorphosed individuals of the Kenyan reed frog, Hyperolius viridiflavus ferniquei, are able completely to regenerate amputated digits, including the morphologically complex digital pad. The sequence of morphological events is very similar to that seen in the typical epimorphic regeneration of amphibian extremities. Amputated forearms typically produce hypomorphic spike regenerates. Despite the lack of underlying hand and digital structures, an apical "digital" pad commonly differentiates.

Animals↗
PubMedDate not supplied

Growth cone migration across extracellular matrix components depends on integrin, but migration across glioma cells does not.

To promote neurite elongation, nerve growth cones must adhere to other surfaces. A complex of integral membrane glycoproteins mediates cell binding to the extracellular glycoproteins fibronectin and laminin (Horwitz et al., J Cell Biol 101:2134-2144, 1985). The receptor complex, named integrin, binds to fibronectin by recognition of a specific peptide sequence, Arg-Gly-Asp-Ser (RGDS), in the fibronectin molecule (Pierschbacher and Ruoslahti, Proc Natl Acad Sci USA 81:5985-5988, 1984). We have used antibodies to integrin and an RGDS synthetic peptide to probe the functions of integrin in the migration of growth cones extended from sensory and spinal cord neurons of chick embryos. Analyses of time lapse videotapes of growth cone migration before and after adding RGDS indicated that 2 mM RGDS rapidly inhibits growth cone movement on substrata coated with fibronectin or a fragment of fibronectin containing the RGDS sequence. RGDS has no effect on growth cone movement on laminin or on a surface coated with material deposited from heart conditioned medium. However, a monclonal antibody to the integrin complex (10 micrograms/ml CSAT) completely blocks growth cone movement on substrata treated with fibronectin, laminin, or heart conditioned medium. Thus integrin may be involved in growth cone adhesion to several extracellular molecules, although the selective effects of RGDS indicate that the integrin complex may have heterogeneous sites for interaction with different components of the extracellular matrix. CSAT antibody has no discernible effect, however, on growth cone migration across the upper surfaces of C6 glioma cells. These data indicate that the surfaces of nerve growth cones contain multiple binding molecules that mediate different adhesive interactions during migration.

Animals↗
PubMedDate not supplied

Cell adhesion and neurite extension in response to two proteolytic fragments of laminin.

Studies from several laboratories have suggested that laminin contains at least two domains that selectively mediate cell type-specific behavior. In this study, two proteolytic fragments of laminin are evaluated for their ability to interact with three different populations of embryonic chicken cells. A 600 kDa thrombin fragment, derived from the central portion of the laminin molecule, supports attachment of dorsal root ganglion (DRG), spinal cord (SC), and heart cells. Neurons from both DRGs and SCs extend neurites in response to this fragment. Quantitatively, both cell adhesion and neurite extension on the 600 kDa fragment are comparable to these responses to intact laminin. A 440 kDa chymotrypsin fragment, derived from either intact laminin or the 600 kDa fragment, does not support equivalent responses. Fewer DRG cells attach to this fragment and neurites are shorter than on the 600 kDa fragment. Heart and SC cell attachment is also reduced in comparison with activity of the 600 kDa fragment, and SC neurites do not form on the 440 kDa fragment. These results suggest that there are at least two cell binding domains in the laminin molecule, one with which a variety of cell types can interact and another that may mediate more restricted cellular responses. The latter site appears to be relatively inactive for SC and heart cell adhesion but supports limited attachment and neurite extension by DRG neurons.

Animals↗