Differential cell adhesion molecule expression and lymphocyte mobilisation during prolonged aerobic exercise

This study was undertaken to determine the cell adhesion molecule profile of CD4⁺, CD8^hi and CD56⁺ lymphocytes, which are mobilised to and from the peripheral blood during and after prolonged aerobic exercise. Ten healthy males (21–35 years old) were tested on two occasions, separated by at least 14 days. On the first occasion, subjects were examined in a rested state but did not exercise. On the second occasion, the same subjects were examined at the same time of day before, during and after 2 h of exercise at 65% of peak oxygen consumption. Blood samples obtained at rest (t ₀), during (at 0.5, 1, 1.5 and 2 h, t _0.5, t ₁, t _1.5 and t ₂, respectively) and after (at 4 and 24 h, t ₄ and t ₂₄, respectively) exercise were analysed by two-colour flow cytometry for CD4⁺, CD8^hi and CD56⁺ cell surface expression, and density of CD62L, CD49d and CD11a. At t ₂, circulating concentrations of CD56⁺, CD8^hi and CD4⁺ lymphocytes had increased (P<0.05) by 330%, 105% and 30%, respectively. The majority of CD4⁺, CD8^hi and CD56⁺ lymphocytes mobilised to the blood at t ₂ were CD62L^– and CD11a^hi, although populations of CD4⁺ and CD56⁺ cells that expressed CD62L⁺ and CD11a^lo were also mobilised. Changes in subset concentrations at t _0.5 were positively associated (r=0.63; P<0.01) with their corresponding mean surface density of CD11a at t ₀. Our findings suggest that the differential mobilisation of lymphocytes during prolonged aerobic exercise is linked to the surface expression of CD11a (i.e. lymphocyte-function-associated antigen-1). However, mechanisms unrelated to CD11a expression also appear to be involved. Electronic Publication     

Exercise-induced changes in the expression of surface adhesion molecules on circulating granulocytes and lymphocytes subpopulations

This study examined the relationship between exercise-induced changes in the concentration of circulating immunocompetent cells and their surface expression of adhesion molecules: L-selectin (CD62L) and three ₂-integrins [LFA-1(CD11a/CD18), Mac-1 (CD11b/CD18), and p150/95(CD11c/CD18)]. Eight young male volunteers exercised on a cycle ergometer for 60 min at 60% maximal oxygen uptake. Peripheral blood samples, collected every 30 min throughout exercise and during the 2-h recovery period, were used for flow-cytometric analysis. The experimental results were compared with control data obtained ever 60 min at corresponding times of the nonexercise day. The exercise regimen induced a granulocytosis and a lymphocytosis, mainly due to an elevation of CD8⁺ and CD16⁺ cells. During recovery, a further granulocytosis occurred but accompanied by a lymphopenia. The increased CD8⁺ cell-count during exercise was characterized by a selective mobilization of the CD62L^– and CD11a^high cells, i.e.primed CD8⁺ cells. A postexercise suppression of CD4⁺ cell-count was derived only from CD62L⁺ cells. The CD11b⁺ and CD11c⁺ lymphocytes also increased during exercise, largely attributable to an increase in CD16⁺ cells which co-expressed CD11b and CD11c molecules. The CD62L surface density of granulocytes increased significantly during recovery. This resulted from a selective influx of CD62L^high granulocytes into the circulation. There were no significant changes in per-cell density of the three ₂-integrins on granulocytes and lymphocytes throughout the experimental period. These results suggest that the cell-surface expression of CD62L (and CD I la) molecules is associated with the differential mobilization of CD8⁺ cells during exercise, the postexercise suppression of CD4^– cell-counts and the granulocytosis following exercise.     

Morphine-induced enhancement in the granulocyte response to thioglycollate administration in the rat

The present study determined the pharmacological effects of acute morphine treatment on the granulocyte phase of the peritoneal inflammatory response to thioglycollate (TG) in rats. Dual-color flow cytometry using anti-CD11b/c-PE mAb in combination with HIS48-FITC mAb allowed for the determination of morphine's effects on 4 inflammatory cell subsets: CD11b/c⁺HIS48^med granulocytes; CD11b/c^hiHIS48^neg/lo activated macrophages; CD11b/c^–HIS48^– lymphocytes; and CD11b/c⁺HIS48^hi cells (a monocyte/macrophage and granulocyte subset). Morphine produced a dose-dependent increase in a select subset of inflammatory peritoneal cells, the CD11b/c⁺HIS48^med granulocytes. The effect of morphine was time-dependent, with significant effects first apparent at 4 hr after TG, but the administration of morphine 1 hr before or simultaneously with TG produced a similar increase in CD11b/c⁺HIS48^med granulocytes. Naltrexone completely antagonized the morphine-induced increase in CD11b/c⁺HIS48^med granulocytes. Collectively, these studies show that a single administration of morphine produces a time-dependent, dose-dependent, opioid receptor-mediated enhancement in the peritoneal granulocyte response to TG.     

The inotropic effect of atrial natriuretic factor in the anesthetized rabbit

This study was designed to investigate whether atrial natriuretic factor (ANF) administered over the physiological, pathological and pharmacological range has a negative inotropic action on the heart. Anesthetized rabbits were infused with increasing doses of ANF (0.05, 0.25 and 0.5g kg^–1min^–1), while measuring hemodynamic variables including the maximum rate of change of left ventricular pressure (dP/dt _max) as an index of inotropic state. Plasma levels of immunoreactive ANF (iANF) were measured to relate the hemodynamic changes to actual plasma levels of the peptide. Administration of ANF was associated with decreases in blood pressure, left ventricular pressure and dP/dt _max so that after 0.5 g kg^–1 min^–1 infusion, these variables had decreased by 21±2 mmHg, 21±5.3 mmHg and 925±175 mmHg/s, respectively (P<0.01). There were no significant changes in right atrial pressure, left ventricular end-diastolic pressure or heart rate. Since dP/dt _max can be influenced by changing hemodynamic variables and baroreflex changes, a second group of rabbits was studied in which afterload and heart rate were held artificially constant. Again, in this group of rabbits, infusions of ANF led to decreasing inotropic state, so that at the highest infusion rate, a 14% decrease in dP/dt _max was observed (P<0.05). By comparison, hydralazine, a drug which causes active vasodilatation but no direct inotropic action, significantly (P<0.01) decreased blood pressure, left ventricular pressure and dP/dt _max when infused at a rate of 10 g kg^–1 min^–1. However, in animals in which afterload was controlled, hydralazine did not affect any of the variables measured. The results indicate that ANF does have a negative inotropic action in the anesthetized rabbit.     

Polymerization of 1,3‐Pentadiene Initiated by Aluminium Trichloride in Nonpolar Solvent: Pseudo‐Control is Explained by Continuous Grafting

Summary: The cationic polymerization of 1,3‐pentadiene initiated by AlCl₃ was studied in nonpolar solvent. It was previously shown that at room temperature the active species were long‐lived and that the number‐average molar mass of the polymer chains was increasing with the polymerization yield. In order to explain this apparent control, the macromolecules were labeled with a transfer agent, triphenylamine (NPh₃). The latter binds to active species by electrophilic aromatic substitution. The labeling of the polymer chains indicated that at 20 °C the polymer chains mainly contained one NPh₃ molecule per macromolecule while the NPh₃ content was higher for the high molar mass chains due to a “grafting from” polymer transfer mechanism. Thus, the pseudo‐control was assigned to the branching reactions. The labeling process by NPh₃ also succeeded at ?10 °C. Whereas at ?10 °C a dialkylation of NPh₃ was observed, a trialkylation at 20 °C was obtained. The analysis of the polymer microstructure at both temperatures highlighted an interaction between the active centers and NPh₃. This paper also describes a process to synthesize tri‐arm stars polymers by cationic polymerization.

RI SEC chromatograms of soluble polymers synthesized at 20 °C in the presence of NPh₃ with increasing reaction times (r = [NPh₃]/[AlCl₃] = 1); (a) t = 0.25 h, (b) t = 0.5 h, (c) t = 1 h, (d) t = 2 h, (e) t = 18 h, (f) t = 48 h; [AlCl₃] = 2.3 × 10^?2 mol · L^?1, [1,3‐pentadiene] = 1.6 mol · L^?1, pentane.     

Myeloperoxidase in human lung lavage

The origin of myeloperoxidase (MPO) in bronchoalveolar lavage (BAL) was investigated in the first part of the study. Radioimmunoassay of the cellular and supernatant MPO content as well as the peroxidase-antiperoxidase (PAP) technique were employed to determine the cellular source of MPO. The concentrations of MPO were measured in serum and BAL in the second part of the study. The aim was to determine whether the capillary bed was also a source of MPO. Neutrophil numbers in BALs obtained from 20 healthy subjects correlated significantly to the concentrations of MPO in cell-free BAL supernatans (r=0.643,P0.01). The cellular content of MPO in mixed BAL cells was significantly correlated to the number of neutrophils in the mixture (r=0.536,P<0.05), but not to the number of any other cells. Moreover, the PAP-technique identified MPO in lung tissue neutrophils in resection specimens obtained from three patients undergoing surgery. This technique also revealed strong MPO activity in all BAL neutrophils and a weak activity in merely 4% of the alveolar macrophages in cytospin preparations obtained from seven BALs. High BAL/serum ratio of MPO concentrations suggests that MPO is of local origin, rather than passively diffused from the circulating pool. We therefore conclude that strong evidence suggests that MPO in BAL originates from lung neutrophils and that BAL MPO content may be used to estimate the neutrophil presence or activation in epithelium lining fluid.     

Chloride and sodium transport across bovine tracheal epithelium: Effects of secretagogues and indomethacin

The regulation of ion transport in bovine tracheal epithelium was studied in vitro. In the absence of exogenous midifiers of ion transport, average values for transepithelial electrical potential difference (_t), short-circuit-current (I _sc) and tissue resistance (R _t) were 35.4 mV (lumen negative), 5.4 Eq·h^–1·cm^–2 and 187 ·cm² respectively; net Cl secretion (3.2 Eq·h^–1·cm^–2) and net Na absorption (1.3 Eq·h^–1·cm²) accounted for 82% of theI _sc. Amiloride reduced (₁) andI _sc, and increasedR _t. The values of (_t),R _t andI _sc obtained following addition of theophylline, epinephrine or prostaglandin E₁ (PGE₁) were not different from control values. Theophylline aldo did not alter Na and Cl fluxes but it increased tissue cAMP content 3-fold. Indomethacin did not affect (_t) but it increasedR _t and net Na absorption, and decreasedI _sc and net Cl secretion; it did not significantly reduce tissue cAMP. When added to indomethacin-treated tissues, epinephrine restoredI _sc,R _t and Na and Cl fluxes to control levels and increased tissue cAMP 3-fold. Similary, when PGE₁ was added to indomethacin-treated tissues,I _sc andR _t were restored to control levels.We conclude that: (1) bovine tracheal epithelium, like its canine counterpart, absorbs Na and secretes Cl; the two tissues differ, however, in two ways: the spontaneous rate of Na absorption is higher in bovine trachea and the spontaneous rate of Cl secretion cannot be further increased in bovine trachea by secretagogues; (2) Cl secretion and Na absorption in bovine trachea are normally regulated by endogenous prostaglandins; (3) although cAMP may mediate changes in ion transport, a strict correlation between tissue cAMP content and Na and Cl transport rates is not evident; and (4) Na absorptive and Cl secretory rates are reciprocally related suggesting that both processes are present in the same cells.     

Chronic intracerebroventricular delivery of the secretory phospholipase A2 inhibitor, 12-epi-scalaradial, does not improve outcome after focal cerebral ischemia–reperfusion in rats

Phospholipase A₂s (PLA₂s) seem to be involved in the pathophysiology of ischemic brain injury, but their specific role is far from being completely understood. The present study was carried out to ascertain how and to what extent secretory PLA₂s (sPLA₂s) activity influences outcome after cerebral ischemia–reperfusion, and to correlate this with the inflammatory response. To do this we used the potent and selective sPLA₂ inhibitor, 12-epi-scalaradial. Male Wistar rats were separated into three groups: a control group receiving intracerebroventricular vehicle, and two groups receiving intracerebroventricular 0.005 or 0.5 μg/h 12-epi-scalaradial. Every animal was subjected to middle cerebral artery (MCA) occlusion (90 min, intraluminal thread technique) under continuous monitorization of cerebrocortical perfusion (CP, laser-Doppler flowmetry), followed by reperfusion (3 days). Neurological status, infarct volume, and myeloperoxidase (MPO) activity were the main end points. Three days after the 90-min ischemia period, neurological examination did not reveal significant differences between the three groups of rats. Control rats showed a mean infarct volume of 145.9 ± 24.7 mm³ (21 ± 4.1% of the ipsilateral hemisphere volume), while mean infarct volume in rats treated with 0.005 or 0.5 μg/h 12-epi-scalaradial increased to 164.8 ± 86.8 mm³ (22.0 ± 10.9%) and 211.5 ± 12.2 mm³ (28 ± 3%, P < 0.05), respectively. Treatment with the highest dose of 12-epi-scalaradial (0.5 μg/h) increased MPO activity in the ipsilateral hemisphere by about 140% (from 0.59 ± 0.59 to 1.42 ± 1.03 units of activity/g of tissue in comparison with the control ischemic hemisphere, P < 0.05). Overall, our results point to a positive rather than a negative influence of sPLA₂ activity during ischemia. This, along with its inability to decrease the inflammatory response, does not allow to propose the use of 12-epi-scalardial as a potential drug for stroke therapy.     

Adhesion dependent release of hepatocyte growth factor and interleukin-1 receptor antagonist from human blood granulocytes and monocytes: Evidence for the involvement of plasma IgG,complement C3 and β2 integrin

Objective:Evolving evidence of anti-inflammatory effects is observed in patients with rheumatoid arthritis or ulcerative colitis following periodic adsorptive granulocyte and monocyte (GM) apheresis with a column containing cellulose acetate (CA) beads as apheresis carriers. This study was undertaken to obtain insights into mechanisms of anti-inflammatory actions of adsorptive GM apheresis with CA beads. Methods:In a series of in-vitro experiments, we investigated the effects of plasma proteins and the leucocytes 2 integrin (CD18) on granulocyte adsorption to CA beads. Results:Granulocyte adsorption to CA beads required plasma IgG, the complement C3 and was inhibited by an antibody to leucocytes CD18. Further, hepatocyte growth factor (HGF) and interleukin-1 receptor antagonist (IL-1ra) which have strong anti-inflammatory actions were released by granulocytes that adhered to CA beads. Conclusions:Plasma IgG, C3 derived complement activation fragments and leucocytes CD18 are involved in granulocyte adhesion to CA beads and hence the release of HGF and IL-1ra.Received 27 October 2003; returned for revision 16 December 2003; accepted by M. J. Parnham 8 January 2004     

Virtual elimination of the interference of unstirred water layers on intestinal sugar transport kinetics by use of the tissue accumulation method at appropriate shaking rates

The intestinal transport of sugars and amino acids seems to follow Michaelis-Menten kinetics, but the presence of unstirred water layers at the outer face of the brush border membrane may distort kinetic measurements. According to current theory, the capacity parameter,J _mc ^max would not be affected, but theK _t would be increased to a higher value,K _t , in proportion to the thickness of the unstirred water layer,d.We reasoned that by increasing the shaking rate in the tissue accumulation method,d might drop to such small values thatK _t would fall to a constant level practically equal to the trueK _t .We measuredd-galactose influx into rings of everted hamster intestine as a function of both the substrate concentration and the shaking rate. Our results show that as the circular stirring rate increases from 0.38–6.2 Hz,J _mc ^max remains constant, as expected, butK _t first drops, then levels off to reach a plateau between 2 and 6.2 Hz. We conclude that the averageK _t values in this frequency range (K _t =7.4 mM) represent the true transportK _t . Furthermore, all previous kinetic work performed in our laboratory has been carried out under identical conditions, including shaking rates of 4 Hz. The validity of our preceding results is thus upheld.     

Localisation and characterisation of functional vasoactive intestinal peptide receptors in feline kidney

Specific ¹²⁵I-labelled vasoactive intestinal peptide (VIP) binding was determined in feline renal cortical and medullary plasma membranes. For the cortex, Scatchard analysis of the data resulted in a curvilinear plot with a high-affinity site K _0.5 of 8.4±2.6 nmol l^–1 (SE, n=6) and a second low-affinity site K _0.5 204 ± 16 nmol l^–1 with binding site concentrations (B _max) of 385±44.5 and 2710±181.3 fmol mg protein^–1 respectively. Conversely a similar analysis of the results obtained for outer medullary membranes gave a single site with a K _0.5 of 1.2±0.2 nmol l^–1 (SE, n=4) and B _max of 157.8±24.7 fmol mg^–1. Inner medullary membrane binding data. Gave a single site of lower affinity (K _0.5= 62.5±21.6 nmol l^–1; n=3). Structurally related peptides, glucagon and secretin, were ineffective (up to 1 mol l^–1) in displacing VIP from specific sites in both cortex and medulla. Porcine PHI 1–27 (a peptide having N-terminal histidine and C-terminal isoleucine) and a VIP antagonist [4-Cl-D-Phe⁶Leu¹⁷]VIP both displaced ¹²⁵I-VIP from cortical and medullary membrane binding sites with IC₅₀ values of 43.0 nmol l^–1 and 1.3 mol l^–1 (cortex) and 132.0 nmol l^–1 and 1.5 mol l^–1 (medulla) respectively. The localisation of specific VIP binding sites in feline kidney was investigated further by in vitro autoradiography. A high density of binding sites was visible at the cortico-medullary boundary as well as in the outer stripe of the outer medulla and in radial structures projecting into the cortex. There was a moderate density of binding sites in the superficial cortex. In addition the distribution of tubular VIP-sensitive adenylate cyclase was determined in microdissected nephron segments. In the presence of 10 mol l^–1 GTP, 1 mol l^–1 VIP effected marked stimulations over basal adenylate cyclase activity in medullary collecting tubules (4.7-fold), the bright and granular portions of the distal convoluted tubule (4.1- and 2.2-fold respectively) and in the pars recta of the proximal tubule (2.7-fold). Thus VIP-responsive adenylate cyclase has a discrete localisation in the feline nephron, which appears to correlate with specific binding sites as defined by autoradiography.     

Decreased Leukotriene Release from Neutrophils after Severe Trauma: Role of Immature Cells

Polymorphonuclear granulocytes (PMN) play a key role in host defense against microbial infections. After severe trauma PMN show cellular dysfunctions including chemotactic migration, phagocytosis, and bacterial killing. In these settings the contribution of the cellular matruation stage compared to functional activities has not been investigated. Polymorphonuclear granulocytes are potent producers of lipid mediators via the 5-lipoxygenase (5-LO) pathway (leukotrienes, LTs) which exert important proinflammatory and immunoregulatory activities. We analyzed leukotriene generation from PMN-fractions (N = 23) of 15 polytrauma patients in comparison to 17 healthy donor cell fractions and correlated this lipid mediator release to the hematopoietic maturation stage of respective PMN. Polymorphonuclear granulocytes were isolated from EDTA-anticoagulated peripheral blood employing a one step procedure based on a discontinuous double Ficoll-gradient. Cells (5 × 10⁶/500 l phosphate-buffered saline) were stimulated for 20 min at 37°C with 1 M Ca-ionophor A23187 in the presence of 1 mM Ca⁺⁺ and 0.5 mM Mg⁺⁺. Leukotrienes were analyzed by reversed-phase HPLC. Expression of 5-lipoxygenase (5-LO) was additionally determined by Western blot. Maturation stage of PMN was quantitated by Pappenheim-staining of cell smears. After polytrauma the generation of leukotrienes from PMN was individually diminished. Synthesis of enzymatically formed metabolites (LTB₄, OH-LTB₄ and COOH-LTB₄) was concomitantly reduced. The decresaed leukotriene synthesis strongly correlated (r² = 0.907, P < 0.0001) to the occurrence of immature PMN (mostly band cells). The expression of 5-lipoxygenase in PMN fractions consisting mainly of band cells was decreased. Our results provide evidence that posttraumatic granulocyte dysfunction is partly due to immature functional cell capacities.     

Anti-inflammatory effect of granulocyte and monocyte adsorption apheresis in a rabbit model of immune arthritis

In active rheumatoid arthritis, large numbers of granulocytes and macrophages are found in the inflamed joints. These leucocytes can promote inflammation and tissue injury by releasing inflammatory cytokines, proteinases and oxygen derivatives. To see if granulocyte and monocyte (GM) depletion produces anti-inflammatory effect, GM adsorption apheresis was performed in rabbits with immune arthritis by using a column (Adacolumn) filled with cellulose diacetate beads (G-1 beads) as adsorptive carriers which selectively adsorb CD11b positive GMs. Injection of ovalbumin into the knee joints of ovalbumin-sensitized rabbits caused a marked increase in peripheral blood leucocytes, joint swelling, increased granulocyte adhesion to G-1 beads and elevated TNF- production by peripheral blood mononuclear cells (PBMC). When rabbits received a 60 min adsorption apheresis, there was suppression of CD11b positive leucocyte infiltration into the joint and reduced joint swelling (P < 0.01) compared with controls. Additionally, there was a significant (p < 0.01) suppression of TNF- production by PBMC in the post column blood. These results suggest that GM depletion may serve as a non-pharmacological strategy to modify inflammatory disorders.     

Microelectrode determination of oxyntic cell pH in intact frog gastric mucosa. Effect of histamine

Intracellular pH (pH_i) of acid-secreting cells was measured in intact gastric fundus mucosa of Rana esculenta with double-barrelled pH microelectrodes. Tissues were mounted, serosal side up, between two half chambers and individual cells were impaled after microsurgical removal of the serosal muscle layer. Transepithelial potential difference (V _t) and resistance (R _t) as well as serosal cell membrane potential (V _s) and pH_i were continuously recorded at rest (0.1 mmol/l cimetidine) or during stimulation (0.5 mmol/l histamine). During chamber perfusion with HCO3 ₃ ^– /CO₂-buffered Ringer solution of pH_o=7.36, V _t and R _t were –21.7, SD±6.0 mV and 229±83 cm²(n=17) while V _s and pH_i averaged –7.3±6.9 mV and 7.4±0.11 (n=25). The latter value is considerably more alkaline than all recent pH_i measurements obtained with microspectrofluorometric techniques on isolated cells, glands or intact tissue. The difference may in part be explained by use of HCO ₃ ^– -free solutions in most of the previous studies because we observed that such solutions decrease pH_i to 6.89±0.18 (n=4). Again, in contrast to recent literature, application of histamine in HCO ₃ ^– /CO₂-buffered solution led to further transient alkalinization by 0.12±0.05 pH unit (n=8). Since in accidental punctures of the gastric gland lumen we noticed that H⁺ secretion only began approximately 5 min after histamine application, we conclude that the histamine-induced initial alkalinization does not reflect stimulation of the H⁺/K⁺ ATPase pump. Alternatively, it may result from histamine-induced activation or inactivation of other ion transporters, one possibility being activation of basolateral Na⁺/H⁺ and Cl^–/HCO ₃ ^– exchangers.     

Influence of isocapnic hyperpnoea on maximal arm cranking performance

Isocapnic hyperpnoea has been shown to reliably produce fatigue of the diaphragm. The aim of the present study was to investigate whether incremental isocapnic hyperpnoea (IH_incr) impairs the arm exercise performance and alters the breathing pattern during subsequent maximal incremental arm cranking. Nine healthy volunteers performed an arm cranking test with prior IH_incr (AC_IH) and without prior IH_incr (AC_control). Minute ventilation (V_̇E), tidal volume (V_T), breathing frequency (f_b), O₂ uptake (O₂), CO₂ elimination (CO₂), respiratory exchange ratio (RER) and end-tidal partial pressure of CO₂ (P_ETCO₂) were measured at three different time intervals (t₁: the average of the 3.30th min to the 6.30th min, t₂: 1 min before the end, t₃: peak value) and expressed as mean (SD). V_T at t₁ and at t₃ was significantly (P<0.05) lower during AC_IH [AC_control: t₁: 1.3 (0.5) l, t_p: 1.9 (0.3) l; AC_IH: t₁: 1.1 (0.3) l, t_p: 1.6 (0.3) l]. f_b at t₁ and t₂ was significantly (P<0.05) higher during AC_IH [AC_control: t₁: 23 (4) breaths min^–1, t₂: 42 (14) breaths min^–1; AC_IH: t₁: 27 (5) breaths min^–1, t₂: 48 (14) breaths min^–1]. The maximal voluntary ventilation (MVV), measured before and immediately after the IH_incr, demonstrated a small but significant decrease from 157 (15) l min^–1 to 150 (14) l min^–1 (P<0.05) after the IH_incr. In conclusion, rapid shallow breathing occurred during maximal arm cranking exercise after IH_incr. The alteration was irrespective of the workload and had already occurred at the start of exercise.     

Morphological changes and membrane potential of human granulocytes under influence of chemotactic peptide and/or echo-virus,type 9

Summary The membrane potential,E _m , of human granulocytes (PMNs), was recorded using glass microelectrodes. The membrane potentialE _m exhibited potential fluctuations accompanied by characteristic changes of cell shape. The periodic potential fluctuations (7-s, 70-s, and 260-s periodicities) ascertained by the autocorrelation technique, suggested the existence of an internal clock. The chemoattractant f-Met-Leu-Phe (FMLP) had no influence on the periodicities, whereas the amplitudes of the fluctuations were increased by it. Treatment of PMNs with Echo 9 virus also resulted in hyperpolarization. The 70-s periodicity disappeared under virus treatment indicating a virus-induced change of the internal program and loss of chemotactic activity.Abbreviations ACF Autocorrelation function - Echo 9 AB virus Echo virus, type 9, strain A Barty - E _m Membrane potential - FMLP N-formyl-methionyl-leucyl-phenylalanine - PMN Human polymorphonuclear granulocyte - t ₁,t ₂,t ₄ Characteristic periodic length - t ₃ Aperiodic decay time     

The influence of age,race, and gender on peripheral blood mononuclear-cell subsets in healthy nonsmokers

To investigate the influence of age, race, and gender on the cellular immune system, we determined T-cell, B-cell, monocyte, natural killer (NK)-cell, and HLA-DR⁺-cell subsets in 266 nonsmokers from a population-based random sample of healthy adults using monoclonal antibodies and flow cytometry. Blacks had a lower total white blood-cell count than whites (P0.0001), due primarily to a decrease in granulocytes. There was no significant difference in absolute lymphocyte count between blacks and whites. Blacks had a higher proportion of CD19⁺ cells (Leu 12⁺ B cells) and a lower proportion of CD3⁺ cells (OKT3⁺ T cells) than whites (P0.01). Female sex and increasing age were independently associated with an increased percentage of CD4⁺ cells (OKT4A⁺ helper-inducer T-cell subset), resulting in a higher helper/suppressor ratio among women and older individuals (P0.05). Black race and increasing age were independently associated with an increased proportion of HLA-DR⁺ cells (P0.0001) which was not attributable to B cells or monocytes. No significant age, race, or gender effects were observed for CD14⁺ cells (Leu M3⁺ monocytes) or CD16⁺ cells (Leu 11A⁺ natural killer cells). These data demonstrate that age, race, and gender are each associated with significant differences in peripheral blood monouclear-cell subsets. Population-based data such as these provide an important foundation for future design and interpretation of human flow cytometry data.     

Kinetics and Modeling of the Radical Polymerization of Trimethylaminoethyl methacrylate chloride in Aqueous Solution

For the radical polymerization of ionized trimethylaminoethyl methacrylate chloride (TMAEMA) in aqueous solution, two strategies to determine the propagation rate coefficient (k_p) are proposed for systems where the pulsed‐laser polymerization–size‐exclusion chromatography (PLP–SEC) method fails. This problem occurs with some fully ionized or sterically highly hindered monomers, where termination may become too slow. As TMAEMA is a borderline case with k_p being accessible by PLP–SEC and from single‐pulse–pulsed‐laser polymerization with electron paramagnetic resonance (SP–PLP–EPR) spectroscopy, studies into this monomer allow for judging the quality of the suggested alternative approaches of k_p measurement and serve for consistency checks of the previously published k_p and termination rate coefficient (k_t) data. Within both approaches, k_p/〈k_t〉 ^0.5 is measured via chemically initiated polymerization, with 〈k_t〉 referring to chain‐length‐averaged termination. The k_p/〈k_t〉 ^0.5 data are combined either with k_p/〈k_t〉 values from highly time‐resolved near‐infrared detection of monomer conversion induced by a single laser pulse (SP–PLP–NIR) or with Predici modeling on the basis of known chain‐length‐dependent termination kinetics. As coupled rate coefficients are measured, the obtained k_p data also provide 〈k_t〉 for a particular chain‐length distribution. The differences between propagation and termination rates of nonionized and fully ionized monomers are discussed.

     

Voltage-clamp studies of the Na+/glucose cotransporter cloned from rabbit small intestine

Inward Na⁺ currents associated with the cloned intestinal Na⁺/glucose cotransporter expressed in Xenopus oocytes have been studied using the two-microelectrode voltage-clamp method. The steady-state current/voltage relations showed voltage-dependent (V _m from +20 to –75 mV) and relatively voltage-independent (V _m from –75 to –150 mV) regions. The apparent I _max for Na⁺ and glucose increased with negative membrane potentials, and the apparent K _0.5 for glucose (K _0.5 ^Glc ) depended on V _m and [Na]_o. Increasing [Na]_o from 7 to 110 mmol/l had the same effect in decreasing K _0.5 ^Glc from 0.44 to 0.03 mmol/l as increasing the V _m from –40 to –150 mV. The I/V curves under saturating conditions (20 mmol/l external sugars and 110 mmol/l [Na]_o) were identical for d-glucose, d-galactose, -methyl d-glucopyranoside and 3-O-methyl d-glucoside. The specificity of the cotransporter for sugars was: d-glucose, d-galactose, -methyl d-glucopyranoside > 3-O-methyl d-glucoside d-xylose > d-allose d-mannose. K _i for phlorizin ( 10 mol/l) was independent of V _m at saturating [Na]_o. We conclude that a variety of sugars are transported by the cloned Na⁺/glucose cotransporter at the same maximal rate and that membrane potential affects both the maximal current and the apparent K _0.5 of the cotransporter for Na⁺ and glucose.     

Sekretion,Verteilung und Abbau von Aldosteron bei verschiedenen Hochdruckformen

Zusammenfassung Bei 11 normotensiven Kontrollpersonen, 11 Patienten mit milder essentieller Hypertonie, 5 Patienten mit fortgeschrittener essentieller Hypertonie, 5 Patienten mit primärem Aldosteronismus und 13 Patienten mit Hypertonie in Verbindung mit Nierenarterienstenose wurde die Sekretionsrate (SR) und die metabolische Clearancerate (MCR) von Aldosteron bestimmt. Folgende Determinanten der metabolischen Clearancerate wurden zusammen mit MCR ausA,B, , und, den Konstanten der³H-Aldosteronplasmakonzentration-Zeit-Funktion nach i.v. Injektion von³H-Aldosteron, berechnet: Die GeschwindigkeitskonstantenK ₁ undK ₂ für die Verteilung und den Abbau des Aldosterons, die virtuellen VerteilungsvoluminaV ₁ undV ₂, die Äquilibriumzeitt _eq und die biologische Halbwertszeitt _1/2. Zusätzlich wurden die mittlere Aldosteronplasmakonzentration (mPC) und die mittlere Gesamtmenge austauschbaren Aldosterons (mmP) berechnet.SR, mPC und mmP waren leicht erhöht in den meisten Fällen von milder essentieller Hypertonie und signifikant erhöht bei fortgeschrittener essentieller Hypertonie, bei primärem Aldosteronismus und bei Hypertonie mit Nierenarterienstenose. HinsichtlichA,B,,,K ₁,K ₂,V ₁,V ₂,t _eq ,t _1/2 und MCR war für keine der vier Gruppen von Hochdruckpatienten ein signifikanter Unterschied zur Kontrollgruppe nachzuweisen.Die Ergebnisse erlauben die Schlußfolgerung, daß die Hyperaldosteronämie mit erhöhter Gesamtmenge austauschbaren Aldosterons bei den untersuchten Hochdruckformen aus der erhöhten Aldosteronsekretion resultiert, während Verteilung und Abbau des Hormones unverändert bleiben.Auszug aus der Dissertation von Adalbert Berndt, Meidzinische Fakultät der Johannes Gutenberg-Universität Mainz, 1972.