Showing papers by "University of Colorado Denver published in 1975"

Delayed hypersensitivity in the mouse.

Abstract: Publisher Summary This chapter discusses the delayed-type hypersensitivity (DTH), the prototype model of cellular immune phenomena as it occurs in mice. Most of the recent explosive development in the field of cellular immunology has emphasized the in vitro demonstrations of cellular responses to immunologic challenge and the various products of such stimulated cells, which possibly have in vivo phlogogenic or cytotoxic potential. However, before the full significance of cellular immune responses in in vivo situations can be determined, it will be necessary to transfer the in vitro observations to in vivo delayed hypersensitivity reactions. For this purpose, the mouse appears to be the most likely subject. Footpad tests, flank skin tests, and epicutaneous tests all have become well established and routinely used indicators of DTH in mice. The excellence of mice for studying the pathogenetic roles of DTH in infectious disease is well illustrated by a series of recent experiments on the formation of infectious granulomas around schistosome eggs, deposited in the lungs of mice by intravenous injection.

Two approaches that increase the activity of analogs of adenine nucleosides in animal cells.

Abstract: Summary Deamination of many analogs of adenine nucleosides results in the loss of their chemotherapeutic efficacy. Two approaches have been used in this study to overcome this problem. First, some adenine nucleotides, which are resistant to mammalian adenosine deaminase, are more toxic to animal cells than are the respective nucleosides. For example, 9-β-d-arabinofuranosyladenine 5′-phosphate, a molecule that penetrates the cell without degradation, has a more sustained toxicity against mouse fibroblasts (L-cells) than does 9-β-d-arabinofuranosyladenine (ara-A). Furthermore, L-cells treated with 2′,3′-dideoxyadenosine 5′-phosphate are extensively killed after 48 hr, whereas 2′,3′-dideoxyadenosine is almost nontoxic to L-cells. Specific inhibition of adenosine deaminase by nontoxic concentrations of erythro-9-(2-hydroxy-3-nonyl)adenine greatly potentiates the biological activity of both ara-A and 3′-deoxyadenosine (cordycepin). Simultaneous administration of cytostatic concentrations of ara-A and the inhibitor of adenosine deaminase to L-cells killed greater than 99.9% of the cells in 36 hr. A similar concentration of ara-A plus the deaminase inhibitor also markedly extended the mean survival of mice bearing Ehrlich ascites carcinoma as compared to ara-A alone. A cytostatic concentration of cordycepin (1 × 10 -4 m), administered in the presence of deaminase inhibitor, killed greater than 99.9% of cultured L-cells in only 8 hr. During the latter incubation, accumulation of uridine in acid-insoluble material reached a maximum after 30 min, and incorporation of thymidine into acid-insoluble material was almost totally arrested after 2 hr.

Adenine nucleotides in the secretory granule fraction of rat islets.

Abstract: Concomitant with glucose-induced insulin release, there occurred an increase of ATP from 4.40 plus or minus 0.21 to 23.16 plus or minus 0.52 pmol/100 islets/min (P less than 0.001) in the effluent from perifused rat islets. There is a linear relationship between circulating ATP and insulin levels both in the stimulated and basal state (r = 0.689, P less than 0.01). Islets incubated with labeled adenine for a short period of time (37.5 min) showed no release of radioactivity upon subsequent glucose-induced insulin release. Islets incubated for a prolonged interval with labeled adenine (150 min) showed an increase in acid soluble radioactivity in the effluent during glucose-induced insulin release. Following incubation of the islets with labeled adenine for 150 min, approximately 5% of the homogenate radioactivity was found in the secretory granules. Using column chromatography to separate the adenine nucleotides, the distribution of radioactivity among the various nucleotides in the secretory granule fraction was found to be: AMP 54.42 plus or minus 4.96%, ADP 14.20 plus or minus 1.63%, ATP 15.39 plus or minus 3.84%, and cAMP 16.07 plus or minus 2.11%. The distribution of radioactivity in the effluent adenine nucleotides after glucose-induced insulin release was: AMP 32.83 plus or minus 4.62%, ADP 24.52 plus or minus 2.77%, ATP 28.13 plus or minus 5.45%, and cAMP 26.01 plus or minus 3.34%. The absolute levels of adenine nucleotides in the secretory granules were ATP 4.19 plus or minus 0.88, ATP madp 7.94 plus or minus 2.20 and cAMP 4.46 plus or minus 1.74 pmol/ug prot. The levels in the islet effluent were ATP, 15.30 plus or minus 2.70, ATP qDP, 29.43 plus or minus 3.49 and cAMP 7.66 plus or minus 1.93 pmol/100 islets/min for the first ten min of glucose-stimulated insulin release. Thereafter there was a rapid decline in effluent cAMP while ATP and ADP remained in essentially equivalent amounts. The distribution of radioactivity and absolute levels of the adenine nucleotides in the effluent reflects that found in the secretory granules, confirming previous observations that insulin release is occurring by exocytosis.

Studies of the absorption and removal of propranolol in hypertensive patients during therapy.

Abstract: The variability of plasma propranolol concentrations has been determined in a large group of patients being treated with the drug. Although the average patient achieved a therapeutic plasma level with 160 mg/day, there was marked interpatient variation. This was found to be primarily the result of differences in effective absorption of the drug, which averaged 46% of the oral dose but ranged from 20 to 80%. Propranolol disappeared from plasma with a half-life of 4.7 hours and its removal appeared to follow dose independent kinetics with no evidence of saturation of hepatic metabolism. The derived pharmacokinetic values of volume of distribution and clearance rate have been used to provide guidelines for initiating propranolol therapy intravenously, and the schedule of 8 mg as a loading dose and 0.02 mg/min as a sustaining dose has been suggested.

Histamine H1- and H2-receptors in pulmonary and systemic vasculature of the dog.

Abstract: This study was conducted to identify and clarify the actions of pulmonary and systemic H1- and H2-receptors by utilizing specific histamine receptor antagonists. Histamine was infused in anesthetized dogs during control conditions, after H2-receptor blockade with metiamide, after H1-receptor blockade with chlorpheniramine, and after combined H1- and H2-receptor blockade. Histamine infusion, alone, induced marked systemic vasodilatation, pulmonary vasoconstriction, and transient increases in cardiac output and heart rate. H2-receptor blockade prevented the systemic vasocilatation and potentiated the pulmonary vasoconstriction induced by histamine. H1-receptor blockade augmented the systemic vasodilatation, prevented the pulmonary vasoconstriction, and increased the cardiac output and heart rate responses induced by histamine. Thus, H2-receptors appear to mediate the vasocilatation, tachycardia, and increased cardiac output induced by histamine, whereas H1-receptors appear to mediate the vasoconstrictor and the minimal cardiac depressent actions of histamine. Histamine stimulates only H1- and H2-receptors, since combined H1- and H2-receptor antagonism prevented almost all of the cardiovascular actions of histamine.

Bone resorption of the mandible in progressive systemic sclerosis.

Abstract: Five of 16 patients with progressive systemic sclerosis were found to have bone resorption at the angle of the mandible This finding appears to be closely related to the tightness of the skin of the face, atrophy of the masseter and pterygoid muscles, small size of the oral orifice, and a significantly high frequency in blacks The mandible must therefore be added to the list of those bones that can be resorbed in progressive systemic sclerosis

Production of Sézary-like cells from normal human lymphocytes.

Abstract: The present study was designed to determine if lymphocytes from healthy humans could be stimulated to assume the morphologic appearance of Sezary-like cells. Lymphocyte-rich populations of cells were incubated for 72 hours with pokeweed mitogen and phytohemagglutinin, both potent cellular mitogens. With light microscopy, differential cell counts performed on 0.5μ epoxy resin-embedded sections showed that 5% to 11% of the lymphocytes had cerebriform nuclei, and were designated as Sezary-like cells. The morphological results were confirmed by electron microscopy. Production of Sezary-like cells from stimulated, normal, human lymphocytes suggests that cells with cerebriform nuclei may represent reactive lymphocytes, and may explain their presence in benign inflammatory dermatoses.

Effect of beta-adrenergic blockade and inhibitors of angiotensin II and prostaglandins on renal autoregulation.

Abstract: The role of the renin-angiotensin system and prostaglandins in renal autoregulation was investigated in dog kidneys in situ. Renal autoregulation during decreases in renal arterial pressure (RAP) was examined in animals pretreated with a competitive antagonist of angiotensin ii, [1-sarcosine, 8-glycine] angiotensin II, or one of two chemically dissimilar inhibitors of prostaglandin synthetase, indomethacin and meclofenamate. Because of recent evidence suggesting a role for an intrarenal beta receptor in regulating renin release, renal autoregulation was also examined in animals treated with the beta-adrenergic blocking agent propranolol. In all groups of animals constancy of glomerular filtration rate (GFR) and renal blood flow (RBF) was observed after substantial decreases in RAP to a range of 70-90 mmHg. These studies therefore do not provide evidence in support of a role for angiotensin II, prostaglandins, or an intrarenal beta receptor as mediators of the renal autoregulation of GFR or total RBF.

Effects of diphenylhydantoin, phenobarbital, and diazepam on the metabolism of methylprednisolone and its sodium succinate.

Abstract: The metabolic clearance rates (MCR) of methylprednisolone (MP) (no. = 13) and methylprednisolone-21-Na-hemisuccinate (MPHS) (no. = 6) were studied in normal humans using tritium-labeled steroids. The cumulative appearance of the labeled steroid was examined for the whole urine and for three major urinary fractions. The MCR, half-life, and volume of distribution were, respectively, 383 ± 72 (sd) liters/day, 165 ± 49 minutes, and 61 ± 12 liters for MP, and 234 ± 37, 160 ± 19, and 41 ± 6 for MPHS. Diphenylhydantoin (DPH) administered to 4 subjects increased the MCR of MP from 424 ± 71 to 977 ± 132 (P < 0.01), and decreased the half-life from 149 ± 44 to 69 ± 7 (P < 0.001). Similar effects were found with phenobarbital (PB). Diazepam (DZP) had no effect. Major increases in urinary metabolites after DPH and PB were in the unconjugated ethyl acetate fraction, and this suggests that MP metabolism is significantly altered by hepatic microsomal hydroxylation enzyme induction by DPH and PB, but not DZP. This could ...

Factors influencing the effect of hormones on the accumulation of cyclic AMP in cultured human astrocytoma cells.

Abstract: The characteristics of the effects of catecholamines, prostaglandins, and adenosine on the adenosine 3',5'-monophosphate (cAMP) content of human astrocytoma cells are described. Catecholamines interact with a typical beta-adrenergic receptor, i.e., the order of potency of catecholamines is isoproterenol larger than or equal to epinephrine greater than norepinephrine greater than dopamine, and propranolol is an inhibitor but phentolamine is not. The prostaglandins interact with a receptor that recognized PGE-1, PGE-2, and PGA-1 but not PGF-2-alpha. The effects of PGE-1 are blocked by 7-oxa-13-prostynoic acid, indomethacin, and meclofenamic acid in a rapid, reversible manner. The cells contain another adenylate cyclase-linked receptor that recognizes adenosine and the adenine nucleotides but not guanosine, deoxyadenosine, or adenine. Theophylline and other methylxanthines are competitive inhibitors of the effect of adenosine. Each class of effector appears to stimulate adenylate cyclase by interacting with a structure-specific receptor. This follows from the observation that the effect of each class of agonists can be blocked selectively by the various inhibitors and is consistant with the observation that co-addition of different agonists results in additive effects on accumulation of cAMP. The magnitude of the effect of any of the classes of agonists can be influenced by a variety of factors, some of which may be related to the peculiarities of growth in culture: (1) The cells secrete cAMP into the medium, and the magnitude of this secretion for a given rise in intracellular cAMP is different for different agonists. (2) The exposure of the cells to catecholamines or prostaglandins leads to a loss of responsiveness to a subsequent challenge by the same agonist. The magnitude of the agonist-induced loss of responsiveness is dependent on the concentration of the agonist and the time of exposure. The process is at least partially agonist specific in that exposure of cells to isoproterenol can lead to greater than 90% loss in catecholamine responsiveness with less than 20% loss in responsiveness to prostaglandins. (3) The responsiveness of the cells also changes as a function of the age of the culture and as a function of cell density. (4) Finally, it can be demonstrated that cells maintained in culture for prolonged periods (months to years) may lose responsiveness to specific agonists while responsiveness to other agonists remains unchanges or actually increases. The advantages and disadvantages of the use of cells in culture for studies of the regulation of cAMP metabolism are discussed.

Metabolism of 9-β-d-Arabinofuranosyladenine by Mouse Fibroblasts

Abstract: The metabolism of 9-β-d-arabinofuranosyladenine (araA) by exponentially growing mouse fibroblasts in suspension culture has been investigated. After a 4-hr incubation with 0.1 mm [3H]araA, only 0.14% of the total 3H was in the cell fraction, whereas 48% of the araA in the medium had been deaminated to 9-β-d-arabinofuranosylhypoxanthine. Of the cellular 3H, 80% was acid soluble, and of these 75% was associated with adenine nucleotides and 25% was associated with nucleosides. 9-β-d-arabinofuranosylhypoxanthine comprised 80% of the labeled nucleosides, the rest being araA or adenosine. Following dephosphorylation of the acid-soluble fraction, 80% of the 3H was in araA and 9-β-d-arabinofuranosylhypoxanthine, and 18% was in adenosine. Ninety % of the 3H in the adenine-containing triphosphates was shown to be in arabinosyl compounds, and the remainder was in adenosine and deoxyadenosine. The concentration of cellular 9-β-d-arabinofuranosyladenine 5′-triphosphate was calculated to be 20 µm. The RNA fraction contained 16% of the total cellular 3H. Over 90% of the 3H was associated with the adenosine 2′(3′)-phosphate fraction; the remainder was nucleoside, mainly araA. When the adenosine 2′(3′)-phosphate fraction was dephosphorylated, nearly 70% of the 3H was contained in adenosine, indicating extensive metabolism of araA. The remaining 3H was associated with arabinosyl compounds. The DNA fraction contained 2% of the cellular 3H. After degradation to 5′-monophosphates, the 3H was found mainly in 9-β-d-arabinofuranosyladenine 5′-phosphate; after dephosphorylation 95% of the 3H was in araA. Following degradation to 3′-monophosphates and terminal nucleosides, the majority of the 3H was associated with 9-β-d-arabinofuranosyladenine 3′-phosphate, whereas a minor portion was in the nucleoside. These results suggest that, after incubation with mouse fibroblasts, most of the exogenous araA is deaminated and remains in the medium or is otherwise metabolized. A small amount is phosphorylated to arabinosyl nucleotides that attain inhibitory cellular concentrations, and some 9-β-d-arabinofuranosyladenine 5′-triphosphate is subsequently incorporated in internucleotide linkage into DNA.

Localization of the β Chain of Human Chorionic Gonadotropin on Human Tumor Cells and Placental Cells

Abstract: Summary With the use of peroxidase-labeled antibody to the β chain of human chorionic gonadotropin, sections of ten human malignant tumors were found to react with this antibody. It is postulated that both selective host immunosuppression by tumors and selective maternal immunosuppression by fetal tissues may be mediated by human chorionic gonadotropin.

Uptake of GABA by neuronal and nonneuronal cells in dispersed cell cultures of postnatal rat cerebellum

Abstract: A study was made of the time course and kinetics of [3H]GABA uptake by dispersed cell cultures of postnatal rat cerebellum with and without neuronal cells The properties of GABA neurons were calculated from the biochemical difference between the two types of cultures It was found that for any given concentration of [3H]GABA, or any time up to 20 min, GABA neurons in cultures 21 days in vitro had an average velocity of uptake several orders of magnitude greater than that of nonneuronal cells In addition, the apparent Kmvalues for GABA neurons for high and low affinity uptake were 033 X 10(-6) M and 418 X 10(-4) M, respectively For nonneuronal cells, the apparent Km for high affinity uptake was 029 X 10(-6) M The apparent Vmax values for GABA neurons for high and low affinity uptake were 287 X 10(-6) mol/g DNA/min and 1515 mmol/g DNA/min, respectively For nonneuronal cells, the apparent Vmax for high affinity uptake was 006 X 10(-6) mol/g DNA/min No low affinity uptake system for nonneuronal cells could be detected after correcting the data for binding and diffusion By substituting the apparent kinetic constants in the Michaelis-Menten equation, it was determined that for GABA concentrations of 5 X 10(-9) M to 1 mM or higher over 99% of the GABA should be accumulated by GABA neurons, given equal access of all cells to the label In addition, high affinity uptake of [3H]GABA by GABA neurons was completely blocked by treatment with 02 mM ouabain, whereas that by noneuronal cells was only slightly decreased Most (75-85%) of the [3H]GABA (44 X 10(-6) M) uptake by both GABA neurons and nonneuronal cells was sodium and temperature dependent

Todd's Paralysis: A Cerebrovascular Phenomenon?

Abstract: Postictal transient focal neurological deficits, i.e., Todd's paralysis, at times are correlated with early veins and/or vascular stain angiographically. Radionuclide gamma camera images show that they also may be accompanied by a relative flow hyperperfusion and a cortical rim static image uptake. Using these observations some portion of Todd's paralysis may be explained as the result of focal epileptic discharges that lead to local vasomotor and/or metabolic changes. The functional arterial venous shunting that results could contribute to cortical ischemia and the subsequent clinical deficits.

Alzheimer II astrocytosis following methionine sulfoximine.

Abstract: A light microscopic study was performed during the preictal period following the administration of methionine sulfoximine (MSO) to adult rats. The principal morphologic observation was the development of Alzheimer II astrocytes in gray matter, suggesting that the metabolic abnormality induced by MSO is initially confined to the astrocyte. In view of the association of the Alzheimer II astrocyte with hyperammonemic states, the drug toxicity may be secondary to the presence of ammonia. A possible mechanism involves astrocytes in the development of seizures produced by MSO.

The fine structure of the cockroach subgenual organ.

Abstract: This paper describes the fine structure of the cockroach subgenual organ, a complex ciliated mechanoreceptor that detects vibrations in the substrate upon which the animal stands. Located beneath the knee in each walking leg, the cockroach subgenual organ is a thin, fan-shaped flap of tissue slung across the dorsal blood space of the tibia at right angles to the leg's long axis. It is innervated by approximately 50 chordotonal sensilla. The fine structure of the chordotonal sensilla is is described in detail ; possible transducer sites are discussed.

Age Pigment, A Biochemical Indicator of Intracellular Aging

Abstract: Teleologically, investigators in the field of aging have considered the formation and accumulation of age pigments or lipofuscin as a deleterious event for the complex intracellular biological processes and a poor prognostic indicator for the nerve cell. With this in mind, age pigment has come to be associated with the functional decadence of cells and organs. This prevailing opinion was derived from findings of early neuropathologists who first correlated increased deposition of age pigment in cells with age. White (1889) proposed that pigmented cells in the central nervous system were a sign of functional decadence. On the other hand, Schafer (1893) had maintained that the accumulation of age pigment was, in fact, a sign of neurone functional activity. Since that time, arguments on the intraneuronal role of lipofuscin or age pigment have continued, without clear evidence being presented for either view. At a later date, nutritional studies provided evidence for a second autofluorescent lipopigment which accumulated in vitamin E deficient animals (Martin and Moore, 1936). This second lipopigment was termed ceroid by Lillie et al (1941).

Localization of spherocytosis to chromosome 8 or 12 and report of a family with spherocytosis and a reciprocal translocation.

Abstract: Significant linkage was found between spherocytosis and a translocation involving the short arms of chromosomes 8 and 12. The gene for spherocytosis, therefore, is likely either very close to the centromere of chromosome 8 or on 12p. The unusually high frequency of spontaneous abortion in this family was probably due to this translocation and was unrelated to the spherocytosis.

Neuronal--glial interactions during development and aging.

Abstract: Integration of the central nervous system is an expression of cerebral homeostasis that is essential for the internal ability of the organism to adapt to its changing environment throughout life. It is generally accepted that neurons undergo no further division after differentiation, whereas glial cells continue to proliferate throughout life. The increase in glial cells with advanced age may reflect a compensatory process of the brain to overcome neuronal loss or neuronal functional changes that may occur with age. Therefore, these neuronal-glial interactions during development and aging may play a key role in the integrative capacity of the brain. One of the mechanisms contributing to brain stability is the blood-brain barrier, which regulates the neuronal-glial microenvironment in the mature organism. Neuronal intercommunication is mediated via neurotransmitter substances and a shift may occur from excitation to inhibition and vice versa in some CNS areas with aging. Studies of some aspects of cholinergic, monoaminergic and amino acid neurotransmission show that their maturational patterns are CNS-area specific and that some neurotransmitter processes decline with advanced age. Glial cells, besides participating in the regulation of extraneuronal environment, are also proposed to be involved in neurotransmission mechanisms in the adult and aging CNS and since they are the major CNS cellular compartment that changes with age they may thus contribute significantly to the maintenance of CNS integrative ability and adaptation with age.—Vernadakis, A. Neuronal-glial interactions during development and aging. Federation Proc. 34: 89–95, 1975.

Ultrastructure of the grasshopper proximal femoral chordotonal organ.

Abstract: This paper, the first in a series concerning the neurobiology of sensory cilia, describes the ultrastructure of our chosen model system—the proximal femoral chordotonal organ (FCO) in pro-and mesothoracic grasshopper legs. The FCO is a bundle of 150–200 longitudinally oriented chordotonal sensilla. Each chordotonal sensillum is a mechano-receptive unit that contains two bipolar neurons whose dendrites bear sensory cilia. The structure of the sensory cilia leads us to suggest that they are motile cilia that respond to the mechanical stimulus with an “active stroke” which excites a transducer membrane at the dendrite tip.

Effect of angiotensin II on renal water excretion.

Abstract: In the present study the effect of angiotensin II (AII) on renal water excretion was evaluated. In dogs undergoing a water diuresis, neither the intravenous (IV) (40ng/kg per min) nor intracarotid (5-10 ng/kg per min) infusion of AII significantly altered urinary osmolality (Uosm) or free-water clearance (CH2O). Intravenous infusion of a competitive inhibitor of AII (1-sarcosine,8-glycine AII) into hydropenic dogs also failed to alter Uosm and CH2O significantly. To examine whether AII might suppress, rather than stimulate, vasopressin release, AII was also infused into hydropenic animals. No effect on Uosm and CH2O was observed during the intracarotid infusion. A significant fall in Uosm and rise in CH2O occurred during the intravenous AII infusion, but reversal after cessation of the infusion was incomplete and statistically not significant. Some suppression of antidiuretic hormone (ADH) release during the intravenous infusion of AII, however, was suggested since no similar alteration in renal water excretion was observed during an intravenous AII infusion in hypophysectomized animals receiving a constant infusion of ADH. Taken together, the present results provide no evidence for a direct effect of AII to alter ADH release or to interfere with the peripheral action of ADH. Suppression of ADH release may sometimes occur with pressor doses of intravenous angiotensin, but this effect is clearly less consistent than previously observed with intravenous norepinephrine.