Changes of circadian blood pressure patterns and cardiovascular parameters indicate lateralization of sympathetic activation following hemispheric brain infarction

The effects of left- and right-sided hemispheric brain infarction on variability in circadian blood pressure and cardiovascular measures were investigated in 35 patients to test for asymmetry of the sympathetic consequences of stroke. No significant differences regarding age, size of infarction or extent and frequency of damage to the insular cortex could be detected between the two groups. Patients with right-sided infarction showed a significantly reduced circadian blood pressure variability [diastolic: -1% (95% CI -4 to 1) vs -6% (-9 to -2);P < 0.05] and a higher frequency of nocturnal blood pressure increase (47% vs 35%;P < 0.05) as compared with patients with left-sided infarction. Right-sided infarction was also associated with higher serum noradrenaline concentrations [546 pg/ml (95% CI 415–677) vs 405 pg/ml (266–544);P < 0.05], and ECG more frequently showed QT prolongation (53% vs 35%;P < 0.05) and cardiac arrhythmias (67% vs 20%;P < 0.005). However, irrespective of the hemisphere damaged, patients with insular infarction showed the most pronounced changes of these parameters. In addition, two patients with right-sided strokes (13%) involving the insula, but none with a left-sided infarction, developed myocardial infarction. These findings suggest lateralization of sympathetic activation with right-sided dominance for sympathetic effects following hemispheric stroke.Supported by the Friedrich-Schiedel-Stiftung     

Fast-phase instabilities in normally sighted relatives of congenital nystagmus patients—autosomal dominant and x-chromosome recessive modes of inheritance

Verification of inheritance in congenital nystagmus (CN) is only possible through the identification of more than one affected member in a family, since in a single case there are no accurate clinical differentiations between spontaneous and inherited CN. We performed electronystagmographic examinations (ENG) to search for abnormal involuntary eye movements as a sign of heredity in seemingly unaffected members of CN families.ENG registrations were performed under three test conditions: (1) with the subject fixating a target, (2) with the room lights off and (3) with closed eyes.Fifty normally sighted individuals (group (a) underwent the test procedure to provide a baseline of normality. Five CN families (three dominant, two sex-linked recessive) were tested as group (b). The eye movement recordings were analysed in terms of nystagmus intensity (amplitude x frequency of the involuntary saccade). In every one of the five families, abnormalities in seemingly non-affected members could be demonstrated: in four families, fastphase instabilities, in the fifth family a true (CN) (slowphase instability).All certain gene carriers were diagnosed correctly by the ENG.These findings indicate a method for detecting slightly affected members in dominant pedigrees and female gene carriers in sex-linked mode of transmission.     

Separation of solubilized A2 adenosine receptors of human platelets from non-receptor [3H]NECA binding sites by gel filtration

Summary Human platelet membranes were solubilized with the zwitterionic detergent CHAPS (3-[3-(cholamidopropyl)dimethylammonio]-1-propanesulfonate) and the solubilized extract subjected to gel filtration. Binding of the adenosine receptor agonist [3H]NECA (5-N-ethylcarboxamidoadeno-sine) was measured to the eluted fractions. Two [³H]NECA binding peaks were eluted, the first of them with the void volume. This first peak represented between 10% and 25% of the [³H]NECA binding activity eluted from the column. It bound [³H]NECA in a reversible, saturable and GTP-dependent manner with an affinity of 46 nmol/1 and a binding capacity of 510 fmol/mg protein. Various adenosine receptor ligands competed for the binding of [³H]NECA to the first peak with a pharmacological profile characteristic for the A₂ adenosine receptor as determined from adenylate cyclase experiments. In contrast, most adenosine receptor ligands did not compete for [³H]NECA binding to the second, major peak. These results suggest that a solubilized A₂ receptor-GS protein complex of human platelets can be separated from other [³H]NECA binding sites by gel filtration. This allows reliable radioligand binding studies of the A₂ adenosine receptor of human platelets.Abbreviations CHAPS 3-[3-(cholamidopropyl)dimethylammoniol-l-propanesulfonate - CIA 2-chloroadenosine - CPA N⁶-cyclopentyladenosine - DPX 1,3-diethyl-8-phenylxanthine - NECA 5-N-ethylcarboxamidoadenosine - PAA 2-phenylaminoadenosine - PIA N⁶-phenyhsopropyladenosine - XAC 8-{4-[([{(2-aminoethyl)amino}carbonyl}methyl)oxy]phenyl]-1,3-dipropylxanthine Send offprint requests to M. J. Lohse     

2-Chloro-N6-[3H]cyclopentyladenosine ([3HCCPA) —a high affinity agonist radioligand for A1 adenosine receptors

Summary The tritiated analogue of 2-chloro-N⁶-cyclopentyladenosine (CCPA), an adenosine derivative with subnanomolar affinity and a 10000-fold selectivity for A₁ adenosine receptors, has been examined as a new agonist radioligand. [³H]CCPA was prepared with a specific radioactivity of 1.58 TBq/mmol (43 Ci/mmol) and bound in a reversible manner to A₁ receptors from rat brain membranes with a high affinityK _D-value of 0.2 nmol/l. In the presence of GTP aK _D-value of 13 nmol/l was determined for the low affinity state for agonist binding. Competition of several adenosine receptor agonists and antagonists for [³H]CCPA binding to rat brain membranes confirmed binding to an A₁ receptor. Solubilized A1 receptors bound [³H]CCPA with similar affinity for the high affinity state. At solubilized receptors a reduced association rate was observed in the presence of MgCl₂, as has been shown for the agonist [³H]N⁶-phenylisopropyladenosine ([³H]PIA). [³H]CCPA was also used for detection of A₁ receptors in rat cardio myocyte membranes, a tissue with a very low receptor density. A K_D-value of 0.4 nmol/l and aB _max-value of 16 fmol/ mg protein was determined in these membranes. In human platelet membranes no specific binding of [³H]CCPA was measured at concentrations up to 400 nmol/l, indicating that A2 receptors did not bind [³H]CCPA. Based on the subnanomolar affinity and the high selectivity for A₁ receptors [³H]CCPA proved to be a useful agonist radioligand for characterization of A₁ adenosine receptors also in tissues with very low receptor density.Abbreviations CHA N⁶-cyclopenyadenosine - CPA N⁶-cy-clopentyladen,osine - CCPA 2-chloro-N⁶-cyclopentyladenosine - CCCPA 2-chloro-5-chloro-5-deoxy-N⁶-cyclopentyladenosine; - CHAPS 3-[3-(cholamidopropyl)dimethylammonio]-1-propanesulfonate - DPCPX 8-cyclopentyl-1,3-dipropylxanthine - NECA N-ethylcarboxamidoadenosine - PEI polyethylenimine - PIA N⁶-phenylisopropyladenosine Send offprint requests to K.-N. Klotz at the above address     

Reconstitution of a functional interleukin (IL)-7 receptor demonstrates that the IL-2 receptor γ chain is required for IL-7 signal transduction

The interleukin (IL)-2 receptor γ chain has recently been shown to be a component of the IL-7 and IL-4 receptors. Using a transient transfection assay and the trans-activation of reporter gene constructs which are under the control of cytokine-responsive promoter elements, we have studied signal transduction through the IL-7 receptor (IL-7R). The reporter gene expression was not stimulated by receptors that contained the cytoplasmic domain of the IL-7R, either as intact IL-7R or as part of a chimeric receptor. However, co-expression of the IL-7R with the IL-2 receptor γ chain was able to stimulate gene activation. For maximal stimulation the intact cytoplasmic domains of each chain was required.     

Molecular cloning of a ligand for the inducible T cell gene 4-1BB: a member of an emerging family of cytokines with homology to tumor necrosis factor

4-1BB is an inducible T cell antigen that shows sequence homology to members of an emerging family of cytokine receptors, including those for tumor necrosis factor and nerve growth factor. To aid in the analysis of the function of 4-1BB we have utilized a soluble form of the molecule as a probe to identify and clone the gene which encodes its ligand. The ligand for 4-1BB is a type II membrane glycoprotein that has homology to tumor necrosis factor, lymphotoxin, and the ligands for CD40 and CD27, all of which are themselves ligands to receptors in this superfamily. The gene for 4-IBB is on mouse chromosome 4 and maps close to the p80 form of the tumor necrosis factor receptor as well as the gene for CD30. The gene for 4-IBB ligand maps to mouse chromosome 17, but considerably distal to the tumor necrosis factor and lymphotoxin genes. Interaction of 4-1BB with its ligand induces the proliferation of activated thymocytes and splenic T cells, a response which is mimicked on similar cell populations stimulated with an antibody to 4-1BB.