Plasma Calcitonin in Normal Man: DIFFERENCES BETWEEN MEN AND WOMEN

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Abstract

We measured plasma calcitonin concentrations in healthy volunteers (20 men, ages 23-45 yr, mean, 30 yr; 25 women, ages 21-46 yr, mean, 30 yr) with a radioimmunoassay capable of detecting 5 pg of calcitonin/500 μl incubation volume, or 25 pg/ml of unextracted plasma. All subjects had 4-h calcium infusion (15 mg Ca/kg), and 24 subjects had intravenous pentagastrin injection (0.5 μg/kg) on separate days. Men had higher basal plasma immunoreactive calcitonin concentrations than women (P < 0.001): mean, 49 pg/ml (range, <25-73) and 31 pg/ml (range, <25-51), respectively. 18 of the 20 men (90%) responded to induced hypercalcemia with increases in plasma immunoreactive calcitonin; only 14 of the 25 women (56%) responded. In men, the mean increase of plasma immunoreactive calcitonin±SE was 58±9 pg/ml, but for women was only 25±6 pg/ml. 8 of 10 men (80%) responded to pentagastrin with an increase of plasma immunoreactive calcitonin >30 pg/ml, compared with such a response in only 1 of 14 women (7%). These differences of plasma immunoreactive calcitonin responses between the sexes were statistically significant (calcium infusion, P < 0.02; pentagastrin, P < 0.001). The physiologic importance of these observations is unknown, but we speculate that a lifelong, relative deficiency of calcitonin in some women could play a role in age- and sex-related bone loss, particularly during the estrogen-deficient postmenopausal years.

Authors

Hunter Heath III, Glen W. Sizemore

Characterization of Gonococcal Antigens Responsible for Induction of Bactericidal Antibody in Disseminated Infection: THE ROLE OF GONOCOCCAL ENDOTOXINS

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Abstract

The role of gonococcal antigens in serum bactericidal activity was determined for an isolate of Neisseria gonorrhoeae from a patient with disseminated gonococcal infection (DGI). Gonococcal outer membranes were purified by differential ultracentrifugation of sheared organisms treated with EDTA. The membranes were solubilized in an endotoxin-disaggregating buffer, and the proteins were separated from the endotoxin by molecular sieve chromatography. Chemical characterization of the endotoxin from the DGI strain revealed the presence of heptose (7.8% of carbohydrate composition) and 2-keto-3-deoxyoctonate (6.1%, wt/wt) in concentrations similar to rough endotoxins of gram-negative enteric bacteria. Dermal Schwartzman reactions were positive for this endotoxin (4 μg) and the corresponding outer membrane (139 μg), but negative for the protein fraction (>500 μg). The patient's whole serum or the IgG fraction, each with complement, reduced the number of the infecting organisms by greater than 1 log10 in a bactericidal assay. Outer membrane and its protein and endotoxin fractions (0.8-500 μg) from the DGI strain were separately preincubated with the patient's convalescent serum and specific inhibition of bactericidal activity occurred with the endotoxin fraction (25 μg) and the outer membrane (100 μg); the protein (500 μg) exhibited no inhibition. Similar results were obtained by inhibiting the bactericidal activity of rabbit antiserum, prepared by intravenous inoculation of an isolate from a patient with pelvic inflammatory disease, with antigen purified from that strain. That this was specific immune inhibition and not anticomplementary activity was shown by the failure of these antigens to inhibit other complement-dependent bactericidal systems.

Authors

Peter A. Rice, Dennis L. Kasper

Detection, Pathogenesis, and Prevention of Damage to Human Granulocytes Caused by Interaction with Nylon Wool Fiber: IMPLICATIONS FOR FILTRATION LEUKAPHERESIS

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Abstract

Granulocytes collected by reversible adhesion to nylon wool fiber (NWF) function relatively well in standard in vitro tests; however, they have an abnormally shortened survival time in the circulation. Assuming that this rapid disappearance represents clearance and that recognition by phagocytes is important for such clearance, we used an autologous in vitro cell:cell recognition assay to determine whether phagocytes can detect cellular changes induced by exposure of normal granulocytes to NWF. Human granulocytes incubated with NWF 1 h at 37°C, eluted with 20% acid citrate dextrose plasma, and washed stimulated the hexose monophosphate shunt activity of normal granulocytes an average of twofold (193±40% of controls), indicating a recognition response. NWF-induced granulocyte recognition was not dependent on plasma factors or activated complement components but was dependent on the time that the granulocyte was on the NWF and was maximal by 60 min of exposure. After elution from NWF, granulocytes demonstrated resting glucose oxidation rates only slightly higher than normal; however, during the first 20 min of exposure to NWF, granulocytes increased their rate of 14CO2 production from [1-14C]glucose three- to five-fold. Therefore, experiments were performed to determine whether toxic oxygen metabolites produced by NWF-adherent cells might contribute to recognition. The results showed that (a) normal granulocytes exposed to NWF in the presence of scavengers of superoxide anion (superoxide dismutase) or free radicals (ascorbate, mannitol, or benzoate) and washed before assay did not stimulate glucose oxidation of indicator granulocytes; and (b) NWF granulocytes prepared from cells unable to generate high levels of toxic oxygen metabolites, i.e. cells prepared anaerobically or from a patient with chronic granulomatous disease, also failed to stimulate indicator granulocytes. Human granulocytes placed in contact with NWF show an oxidative burst and become recognizable to other phagocytes. Free radical scavengers are effective in minimizing this recognition conferred on NWF-procured granulocytes.

Authors

John C. Klock, Thomas P. Stossel

Autoantibodies to the Insulin Receptor: EFFECT ON THE INSULIN-RECEPTOR INTERACTION IN IM-9 LYMPHOCYTES

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Abstract

The serum of some patients with insulin-resistant “diabetes” contains antibodies that bind to and block the cell membrane receptors for insulin. In this report, we have characterized the effects of the antireceptor antibodies on the interaction of 125I-insulin with its receptor on the human lymphoblastoid cell line IM-9. Up to 95% of specific insulin binding can be inhibited by pretreatment of the cells with these immunoglobulins. The onset of the inhibitory effect is time- and temperature-dependent, and the effect is reversed extremely slowly if the cells are suspended in a large excess of antibody-free buffer. These features of antibody binding can be easily distinguished from those for insulin binding to its receptor. The inhibitory effect of the antibodies can be reversed by exposure of the cells to conditions known to elute surface immunoglobulins.

Authors

Jeffrey S. Flier, C. Ronald Kahn, David B. Jarrett, Jesse Roth

The Renal Handling of Parathyroid Hormone: ROLE OF PERITUBULAR UPTAKE AND GLOMERULAR FILTRATION

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Abstract

The mechanisms of uptake of parathyroid hormone (PTH) by the kidney was studied in anesthetized dogs before and after ureteral ligation. During constant infusion of bovine PTH (b-PTH 1-84), the renal arteriovenous (A-V) difference for immunoreactive PTH (i-PTH) was 22±2%. After ureteral ligation and no change in renal plasma flow, A-V i-PTH fell to 15±1% (P < 0.01), indicating continued and significant uptake of i-PTH at peritubular sites and a lesser role of glomerular filtration (GF) in the renal uptake of i-PTH. Since, under normal conditions, minimal i-PTH appears in the final urine, the contribution of GF and subsequent tubular reabsorption was further examined in isolated perfused dog kidneys before and after inhibition of tubular reabsorption by potassium cyanide. Urinary i-PTH per 100 ml GF rose from 8±4 ng/min (control) to 170±45 ng/min after potassium cyanide. Thus, i-PTH is normally filtered and reabsorbed by the tubular cells. The physiological role of these two mechanisms of renal PTH uptake was examined by giving single injections of b-PTH 1-84 or synthetic b-PTH 1-34 in the presence of established ureteral ligation. After injection of b-PTH 1-84, renal A-V i-PTH was 20% only while biologically active intact PTH was present (15-20 min). No peritubular uptake of carboxyl terminal PTH fragments was demonstrable. In contrast, after injection of synthetic b-PTH 1-34, renal extraction of N-terminal i-PTH after ureteral ligation (which was 13.4±0.6% vs. 19.6±0.9% in controls) continued for as long as i-PTH persisted in the circulation. These studies indicate that both GF and peritubular uptake are important mechanisms for renal PTH uptake. Renal uptake of carboxyl terminal fragments of PTH is dependent exclusively upon GF and tubular reabsorption, whereas peritubular uptake can only be demonstrated for biologically active b-PTH 1-84 and synthetic b-PTH 1-34.

Authors

Kevin J. Martin, Keith A. Hruska, Jane Lewis, Charles Anderson, Eduardo Slatopolsky

Clinical Relevance of Circulating Immune Complexes in Human Leukemia: ASSOCIATION IN ACUTE LEUKEMIA OF THE PRESENCE OF IMMUNE COMPLEXES WITH UNFAVORABLE PROGNOSIS

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Abstract

The occurrence of circulating immune complexes was investigated in 467 serum samples from 230 leukemia patients using the [125I]Clq-binding test. There was an increased serum [125I]Clq-binding activity in 40% of patients with acute myeloid leukemia, 23% with acute lymphatic leukemia, 46% in blastic crisis of chronic myeloid leukemia, 12% with chronic lymphatic leukemia, and 13% with chronic myeloid leukemia. In 48 patients, serum was also tested for soluble immune complexes by the Raji cell radioassay; the correlation between results of the two tests was significant. The Clq-binding material had properties identical with those of immune complexes. It sedimented as 14-28s material on sucrose density gradient. It contained IgG which could be dissociated at acid pH. Its Clq-binding properties could be removed after passage through anti-IgG immuno-absorbant or after a mild reduction-alkylation treatment, but were not sensitive to deoxyribonuclease treatment. Circulating immune complexes were found most commonly during the blastic stage of leukemia.

Authors

Nicole A. Carpentier, Ghislaine T. Lange, Denis M. Fiere, Gilbert J. Fournie, Paul-Henri Lambert, Peter A. Miescher

The Influence of Thyroid Hormones on In Vitro Erythropoiesis: MEDIATION BY A RECEPTOR WITH BETA ADRENERGIC PROPERTIES

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Abstract

The erythropoietic effect of various thyroid hormones has been studied using erythroid colony formation by canine marrow cells. Although erythropoietin was required for colony growth, physiologic levels of thyroid hormones significantly enhanced colony numbers. The order of potency of the thyroid compounds in their in vitro erythropoietic effect parallels their known calorigenic potency in vivo, suggesting that the in vitro effect is physiologically relevant. A series of studies linked the mechanism of thyroid action to adrenergic receptors on responsive cells. Propranolol, a global β-blocker, inhibited thyroid hormone-responsive erythroid colonies. When adrenergic antagonists having different blocking characteristics were added to culture, the thyroid hormone effect was blocked by those compounds having β2-subspecificity. Velocity sedimentation analysis showed that the peak of colony-forming cells which respond to thyroid hormone and the adrenergic agonist, isoproterenol, sedimented at an identical rate (7.54 mm/h), which is slower than the major peak of colony-forming cells responding to erythropoietin alone (8.62 mm/h). These results demonstrate thyroid hormonal enhancement of in vitro erythroid colony growth which appears mediated by a receptor with β2-adrenergic properties. The data suggest that changes in hormone-target cell interaction may occur during states of abnormal thyroid function.

Authors

William J. Popovic, James E. Brown, John W. Adamson

Human Lung Tissue and Anaphylaxis: EVIDENCE THAT CYCLIC NUCLEOTIDES MODULATE THE IMMUNOLOGIC RELEASE OF MEDIATORS THROUGH EFFECTS ON MICROTUBULAR ASSEMBLY

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Abstract

The addition of specific antigen to IgE-sensitized human lung tissue causes the secretion of the mediators histamine and slow-reacting substance of anaphylaxis. The mechanisms by which increased levels of cyclic AMP suppress and increased levels of cyclic GMP enhance this secretory process were studied. Colchicine, an agent which disrupts many secretory reactions by binding to microtubules in their disassembled 6S form, was a relatively ineffective inhibitor of the antigen-induced release of mediators unless lung fragments were incubated at 4°C for 60 min to induce microtubular disassembly. As colchicine appeared to inhibit the immunologic secretion of mediators from human lung tissue most effectively after microtubular disassembly, the capacity of colchicine to modulate the release reaction indicated the state of microtubular assembly; inhibition by colchicine signaled a shift to the colchicine-sensitive 6S subunits whereas failure to inhibit suggested maintenance in the colchicine-resistant polymerized state.

Authors

Michael Kaliner

Thyroid Dysfunction in Chronic Renal Failure: A STUDY OF THE PITUITARY-THYROID AXIS AND PERIPHERAL TURNOVER KINETICS OF THYROXINE AND TRIIODOTHYRONINE

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Abstract

Thyroid function was evaluated in 46 patients with end-stage kidney disease and 42 normal subjects. Patients were studied before and after the institution of maintenance hemodialysis (HD) and after renal transplantation (RT). Serum total triiodothyronine concentrations (TT3, ng/100 ml, mean±SD) were 63±17 and 83±22 in the non-HD and HD groups, respectively. Values from normal subjects were 128±25 and from RT patients 134±20. The TT3 was in the hypothyroid range (<78 ng/100 ml; 2 SD below normal mean) in 80% of non-HD and 43% of HD patients. Mean serum total thyroxine concentration (TT4), although within the normal range, was lower than the control value. T4-binding globulin capacity was also slightly lower but the difference was not statistically significant. Among patients whose TT4 was 1 SD below the normal mean, the free T4 index was equally depressed, suggesting that factors other than decreased binding capacity might be responsible for the low TT4. In addition, there was a 37% incidence of goiter. Mean serum thyroid-stimulating hormone (TSH) was not elevated and the TSH response to thyrotropin-releasing hormone (TRH) was distinctly blunted, suggesting the possibility of pituitary dysfunction as well. In vivo 125I-l-T4 and 131I-l-T3 kinetics during 0.2 mg/day of l-T4 replacement showed marked reduction in T3 turnover rate in the uremic patients, both before and during HD; the values (μg T3/day, mean±SD) for the different groups were as follows: normal, 33.8±6.1; non-HD, 13.5±2.6; HD, 12.9±3.1; and RT, 30.3±7.1. The low T3 turnover rate was due to impaired extrathyroidal conversion of T4 to T3. The mean percent±SD of metabolized T4 converted to T3 was 37.2±5.8 in normal subjects, 15.7±3.1 in non-HD, 12.8±1.7 in HD, and 34.0±14.7 in RT patients. In contrast, thyroidal T3 secretion rate was not different between the control and the three patient groups. Thus, it appears that uremia affects thyroid function at several levels: (a) subnormal pituitary TSH response to TRH; (b) possible intrathyroidal abnormalities as suggested by slightly decreased TT4 and high incidence of goiter; and (c) abnormal peripheral generation of T3 from T4. Restoration of renal function with RT resulted in normalization of all parameters of thyroid function with the exception of blunted or absent TSH response to TRH. The latter may be a direct consequence of glucocorticoid administration.

Authors

Victoria Sy Lim, Victor S. Fang, Adrian I. Katz, Samuel Refetoff

Platelet Membrane Defects in Glanzmann's Thrombasthenia: EVIDENCE FOR DECREASED AMOUNTS OF TWO MAJOR GLYCOPROTEINS

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Abstract

Platelets from patients with Glanzmann's thrombasthenia have a distinct molecular alteration of the plasma membrane surface, namely decreased amounts of a major glycoprotein designated as IIb (apparent mol wt 142,000). To identify other possible surface defects of thrombasthenic platelets, we labeled the membrane polypeptides of normal and thrombasthenic platelets by two different techniques: lactoperoxidase-catalyzed iodination and galactose oxidase oxidation, followed by reduction with tritiated sodium borohydride. Labeling patterns were determined after the polypeptides were separated by two-dimensional polyacrylamide gel electrophoresis. Before the second dimension was run, platelet samples were incubated with a reducing agent, β-mercapto-ethanol, to cleave the disulfide bonds of certain glycoproteins; the resulting changes in electrophoretic mobility permitted better resolution of individual molecules. Comparison of the labeled polypeptides of normal and thrombasthenic samples after reduction indicated decreased labeling of two major glycoproteins in thrombasthenic platelets: IIb and III (apparent mol wt 114,000). The relative proportions of radioactivity incorporated by these polypeptides were about 60 and 80% less than control values, respectively. With either Coomassie Blue or periodic acid-Schiff's reagent, glycoprotein III stained much less intensely in thrombasthenic compared to normal samples, indicating that the observed labeling deficit was caused by a decreased concentration of the molecule rather than steric inaccessibility on the membrane surface. Analysis of normal plasma membranes by affinity chromatography showed that glycoprotein IIb has receptors for lectin from Lens culinaris, the common lentil, whereas III does not. We conclude that a characteristic feature of Glanzmann's thrombasthenia is a decreased concentration of two discrete glycoproteins in the platelet plasma membrane.

Authors

David R. Phillips, Patricia Poh Agin