A comparison of two types of ankle supports in men with haemophilia and unilateral ankle pain from arthropathy.

INTRODUCTION: Adults with haemophilia frequently have a painful and disordered gait due to ankle arthropathy. AIM: The aim of this study was to determine if pain and gait parameters were affected by the use of different types of ankle bracing. METHODS: We investigated the gait patterns of 17 men with severe haemophilia without bracing, using a fracture boot (FB) and a carbon fibre floor reaction ankle foot orthosis (CF-AFO). Pain relief was determined in each condition. Gait parameters were measured by means of an electronic, pressure sensitive mat. RESULTS: Both brace types relieved pain. Use of a FB altered gait parameters that are associated with movement of the involved and the uninvolved limb during the gait cycle, whereas the use of a CF-AFO did not affect the gait cycle. CONCLUSION: This study suggests that pain relief from both types of braces is identical but use of a CF-AFO does not alter gait patterns.

Cyclic adenosine 3',5'-monophosphate increases the open probability of potassium channels in activated human T cells.

In the present report we describe a cAMP-responsive K channel in activated human T cells. Single channel events were recorded using the patch-clamp technique in cell-attached-patch configuration. The channel was K selective, as determined by reversal potentials under different K gradients, and displayed voltage-independent gating. When the applied potential (Vp) was equal to zero, the conductance of the channel was 21.8 +/- 0.9 pS with 150 mM K in the electrode. Typical patches contained between two and seven channels that were relatively quiet, or silent, before agonist stimulation. Adenosine (20-30 microM) increased the average open time probability from 0.017 +/- 0.008 to 0.108 +/- 0.054 over a period of 108 s. Subsequent addition of the phosphodiesterase inhibitor Ro 20-1724 (0.5 mM) increased the probability of being in the open state to 1.155 +/- 0.407 over a period of 180 s. Channel kinetics were well described by assuming two open and two closed states. Exponential time constants for the open states were 0.51 +/- 0.06 and 4.34 +/- 0.31 ms, and closed state time constants were 0.58 +/- 0.05 and 10.1 3 +/- 2.32 ms. In addition, extracellular ATP (0.3-1.0 mM) decreased channel activity. Moreover, Rp-cAMP (0.5-1.0 mM), an antagonist that specifically blocks the ability of cAMP to bind and activate protein kinase A, failed to inhibit adenosine- and Ro 20-1724-induced increases in channel activity, implying a direct action of cAMP on channel gating.

Ethanol increases K+ conductance in human T-cells.

Ethanol increased the open probability of a K channel in cultured human T-cells. Single-channel currents were studied using the patch-clamp technique in cell-attached configuration. Ethanol increased the number of simultaneously active channels and subsequent current maxima at concentrations of 35 and 50 mM from control levels of 3.2 to 4.6 pA and 8.4 pA, respectively. Current responses were elicited by a 80 mV hyperpolarizing pulse following adjustment to the same resting potential. The channel was K-selective as determined by the reversal potentials under different Na-K gradients. When the pipette contained 155 mM K, single-channel currents had a slope conductance of 28 pS and a reversal potential of -4.3 mV. Baseline current levels often shifted in a negative direction during the application of ethanol, indicating a hyperpolarization of the membrane potential and an increase in channel activity.

A comparison of K+ channel characteristics in human T cells: perforated-patch versus whole-cell recording techniques.

Standard whole-cell records using the patch-clamp technique are obtained after rupturing the cell membrane just below the patch pipette. Inherent problems, such as the disruption of cellular architecture and the displacement of cytosol, are unavoidable. In the present report, a whole-cell recording technique which makes use of a monovalent cation ionophore, nystatin, was applied to lymphocytes. Nystatin-perforated patches allow electrical access to the cell interior while virtually blocking the diffusion of cellular constituents into the electrode. By comparing standard whole-cell and perforated-patch techniques we observed marked differences in: activation, inactivation, and deactivation kinetics; steady-state inactivation; and the conductance-voltage relationship of K+ currents in activated human T cells.

Augmentation of natural cytotoxicity by leucine enkephalin in cultured peripheral blood mononuclear cells from patients infected with human immunodeficiency virus.

Natural Killer (NK) activity of lymphocytes from acquired immunodeficiency syndrome (AIDS) patients is frequently below normal and declines as disease progresses. We studied the potential of leucine enkephalin (leu-enkephalin) to restore this immune parameter by incubating nylon wool nonadherent mononuclear cells from 14 patients in the presence or absence of leu-enkephalin, and measuring NK cytolysis in a standard 51Cr release assay. The NK activity of human immunodeficiency virus antibody positive (HIV+) individuals with some remaining NK lytic ability was significantly augmented by leu-enkephalin concentrations of 10(-10) and 10(-8) M (n = 7). HIV+ patients with no measurable basal level of NK activity (n = 3) were not responsive to stimulation with leu-enkephalin. Human immunodeficiency virus antibody negative (HIV-) individuals (n = 4) responded in a pattern similar to normals. In addition, naloxone, an antagonist of alkaloid and peptide opiates including leu-enkephalin, displayed the properties of an antagonist/agonist, reflecting the immunoregulatory capacities of the endogenous opiate system.

Regulation of human natural cytotoxicity by enkephalins and selective opiate agonists.

This study reports a bidirectional effect of the enkephalins and selective opiate receptor agonists on human natural killer (NK) cell activity. Peripheral blood mononuclear cells (PBMC) were obtained from healthy donors and enriched for T lymphocytes and large granular lymphocytes (LGL) by passage over nylon wool columns. Nylon wool nonadherent cell populations were preincubated for 18 h in the presence of fetal bovine serum with and without methionine-enkephalin, leucine-enkephalin, dynorphin (fragment 1-13), [D-Ser2]-leucine-enkephalin-Thr (DSLET), and [D-Ala2,N Me-Phe4, Gly-ol5]-enkephalin (DAGO). NK activity was measured by a standard 51Cr release assay with radiolabeled K562 cells. The cytolytic capacity of low NK responder populations was enhanced by the endogenous opioids while the NK activity of high responder populations was suppressed. These results suggest an immunoregulatory action of opioid peptides on NK activity. This possibility was confirmed using a serum-free system in conjunction with recombinant interferon-alpha. In addition, the classic opioid receptor antagonist naloxone displayed both antagonist and direct immunomodulatory properties, which may indicate the presence of lymphocyte derived opioid peptides in the culture system.

Rhesus diploid rabies vaccine (adsorbed), a new rabies vaccine. Results of initial clinical studies of preexposure vaccination.

To meet the need for a safe, efficacious, and low-cost rabies vaccination program, the Michigan Department of Public Health developed a new rabies vaccine: rhesus diploid rabies vaccine, adsorbed (RDRV). Initial clinical studies were conducted in 534 volunteers using preexposure protocols consisting of two injections of RDRV given 1, 2, or 4 weeks apart. This new rabies vaccine induced an excellent rabies virus antibody response two to three weeks after vaccination: antibody levels were superior to those reported after duck embryo rabies vaccine and were similar to those reported with human diploid rabies vaccine. In addition, vaccination with RDRV was associated with an acceptable level of local and constitutional symptoms.

Influence of a bovine spleen extract on immunological responses in mice.

The presence of immunological stimulatory and inhibitory activities has been detected in a bovine spleen extract F prepared by acetic extraction of an acetonic powder. F was fractioned after water dilution, by ultrafiltration on an Amicon PM-10 membrane. Two successive ultrafiltrates (mol. wt. less than 10,000) are obtained: U1 which contained the largest pool of the low molecular weight substances, and U2 which was shown previously to be enriched in an immunosuppressive peptide. The biological activities of U1 have been studied compared to those of U2: 1. Added to mouse spleen cells culture, U1, at low dose, stimulated 3H-thymidine incorporation into the DNA of the cells, but inhibited it when large dose was added. In this test, U2 was devoid of stimulatory action. 2. When injected into mice sensitized with sheep red blood cells, three distinct activities were detected: U1 was inhibitory at the sensitization period; at the last step of differentiation of the lymphocyte, U1 was stimulatory at low dose and inhibitory at large dose. As assessed by Biogel P-2 chromatography, this last activity was attributed to the presence in fraction U1 of the immunosuppressive peptide previously characterized in U2.

Immunosuppressive activity of a purified spleen extract (lymphocytic chalone?) is not due to polyamines spermine and spermidine.

Spermine, spermidine and a purified spleen extract (PSE) have been compared in vivo in these three tests: hemolytic plaque forming capacity in sensitized mice, delayed hypersensitivity reaction and 3H-thymidine incorporation into various tissue cells. The results obtained demonstrated that the immunosuppressive activity of PSE cannot be attributed to those polyamines. Ion exchange analysis of PSE before and after acid hydrolysis confirmed the absence of free and/or bound polyamines in the studied extract.