Presynaptic β2-adrenoceptors on the sympathetic nerve fibres of the human saphenous vein: no evidence for involvement in adrenaline-mediated positive feedback loop regulating noradrenergic transmission

Summary Spirally cut strips of human saphenous veins preincubated with ³H-noradrenaline were superfused in the presence of corticosterone and, unless stated otherwise, of cocaine or desipramine. Tritium overflow was stimulated electrically (2 Hz). Adrenaline (in the presence of rauwolscine), isoprenaline and the preferential ₂-adrenoceptor agonist procaterol concentration-dependently increased the electrically evoked tritium overflow. Prenalterol, a -adrenoceptor agonist with moderate preference for ₁-adrenoceptors, was ineffective. The concentration-response curve of isoprenaline was shifted to the right by the nonselective -adrenoceptor antagonist propranolol and by the preferential ₂-adrenoceptor antagonist ICI 118,551, but was not affected by the ₁-selective antagonist atenolol. In experiments on strips preexposed to adrenaline 10 nmol/l (i. e. a concentration higher than that which normally occurs in vivo) for 32 min in the absence of cocaine or desipramine, the electrically evoked ³H overflow was not affected 12 and 44 min after withdrawal of adrenaline, irrespective of whether propranolol was absent or present in the superfusion fluid. — In veins incubated with ³H-adrenaline, a considerable amount of the radioactivity was accumulated. During subsequent superfusion with ³H-adrenaline-free solution, electrical stimulation induced tritium overflow in a tetrodotoxin-sensitive manner. Propranolol failed to modify the evoked tritium overflow. — It is concluded that the sympathetic nerve fibres of the human saphenous vein are endowed with facilitatory presynaptic ₂-adrenoceptors. These receptors do not seem to play a substantial role in a local adrenaline (previously taken up)-mediated positive feedback loop regulating noradrenergic transmission, at least under the present in vitro conditions.This study was supported by a grant of the Deutsche Forschungsgemeinschaft Send offprint requests to M. Göthert     

Comparison of the positive inotropic effects of serotonin,histamine, angiotensin II,endothelin and isoprenaline in the isolated human right atrium

Summary The receptor systems through which serotonin (5-HT), histamine, angiotensin II and endothelin increase the force of contraction were studied in isolated right atria from patients without apparent heart failure.All agonists increased the atrial force of contraction in a concentration-dependent manner; maximal effects, however, were significantly less than those evoked by isoprenaline or Ca²⁺. 5-HT and histamine, but not angiotensin II and endothelin, activated adenylate cyclase, whereas endothelin and angiotensin II stimulated inositol phosphate generation. Experiments with subtype-selective antagonists revealed that histamine effects were mediated by H₂-receptors (sensitive to ranitidine), 5-HT-effects by 5-HT₄-receptors (sensitive to SDZ 205-557) and angiotensin II effects by AT₁-receptors (sensitive to losartan).We conclude that in human right atria the force of contraction can be increased by cyclic AMP-dependent (histamine, 5-HT) and -independent (angiotensin II, endothelin) pathways. Compared to -adrenoceptors, however, all other receptor systems increase the force of contraction only submaximally indicating that the -adrenoceptor pathway is the most important physiological mechanism to regulate force of contraction and/or heart rate in the human heart.Correspondence to O. E. Brodde at the above address     

Impact of HIV-1 replication on immunological evolution during long-term dual-boosted protease inhibitor therapy

To explore CD4-cell and viral evolution in relation to different levels of HIV-1 replication, as observed during protease inhibitor (PI)-based antiretroviral therapy. Adult HIV-1 infected cohort patients, receiving historical salvage therapy with daily doses of saquinavir (2,000 mg), ritonavir (200 mg) and either lopinavir (800 mg) or atazanavir (300 mg) for >36 weeks were retrospectively analysed for highest detectable viral load up to week 96 and assigned to groups according to the viral load level: always <50 copies/ml (1), 50–199 copies/ml (2), 200–499 copies/ml (3) and ≥500 copies/ml (4). A total of 126 patients were evaluated; at baseline, median CD4-cell count was 204/mm³, HIV-1 RNA was 5.13 Log10-copies/ml and duration of prior HIV-1 infection was 11.7 years. Patients were assigned by 43, 30, 7 and 20 % to groups 1–4. Median observation time was 136 weeks (range: 38–304); at weeks 48/96, the CD4-cell gains for groups 1–4 were +88/+209, +209/+349, +67/+300 and +114.5/+ 128, respectively. After fitting data in a linear fixed effect model, ascending CD4 slopes were continuously increasing for group 1, similarly for 2 and clearly decreasing for 3–4 (p = 0.0006). Of 25 individuals from group 4, patient number with major IAS-USA protease mutations increased from 5 to 10 before and after failing PI therapy, whereas minor mutations remained stable (n = 18). On double-boosted PI therapy, CD4-cell increases through week 96 were similar for patients at always undetectable or with detection of low viral load. Viral detection >200 copies/ml was associated with decreasing CD4-cell slopes and emergence of major mutations, supporting this as benchmark for virological failure definition on PI therapy.     

Risks and benefits of optimised medical and revascularisation therapy in elderly patients with angina--on-treatment analysis of the TIME trial.

AIM: To assess treatment effects of optimised medical therapy and PCI or CABG surgery on one-year outcome in patients 75 years old with chronic angina. METHODS AND RESULTS: On-treatment analysis of the TIME data: all re-vascularised patients (REVASC n=174: 112 randomised to revascularisation and 62 to drugs with late revascularisation) were compared to all patients on continued drug therapy (MED n=127: 86 randomised to drugs and 41 to revascularisation only). Baseline characteristics of both groups were similar (age 80 +/- 4 years). Risk of death at one year (adjusted hazard ratio (HR)=1.31; 95%-CI: 0.58-2.99; P=0.52) and of death/infarction (adjusted hazard RATIO=1.77; 95%-CI 0.91-3.41; P=0.09) were comparable between REVASC and MED patients. Furthermore, the risk of death within 30 days was even slightly lower among REVASC patients (unadjusted hazard RATIO=0.73; 95%-CI: 0.21-2.53; P=0.98). Overall, REVASC patients had greater improvements in symptoms and well-being than MED patients (P<0.01). Surgical patients had similar mortality rates as angioplasty patients, but they also had greater symptomatic improvements (P<0.01). CONCLUSION: Treated medically, elderly patients with chronic angina have a similarly high 30-day and one-year mortality as patients of the same age being re-vascularised; however, they can expect lower improvements in symptoms and well being.     

Quantitative analysis of estrogen receptor heterogeneity in breast cancer

Immunohistochemical analyses (IHC) of biomarkers are extensively used for tumor characterization and as prognostic and predictive measures. The current standard of single slide analysis assumes that one 5 microM section is representative of the entire tumor. We used our automated image analysis technology (AQUA) using a modified IHC technique with fluorophores to compare estrogen receptor (ER) expression in multiple blocks/slides from cases of primary breast cancer with the objective of quantifying tumor heterogeneity within sections and between blocks. To normalize our ER scores and allow slide-to-slide comparisons, 0.6 microm histospots of representative breast cancer cases with known ER scores were assembled into a 'gold standard array' (GSA) and placed adjacently to each whole section. Overall, there was excellent correlation between AQUA scores and the pathologist's scores and reproducibility of GSA scores (mean linear regression R value 0.8903). Twenty-nine slides from 11 surgical cases were then analyzed totaling over 2000 AQUA images. Using standard binary assignments of AQUA (>10) and pathologist's (>10%) scores as being positive, there was fair concordancy between AQUA and pathologist scores (73%) and between slides from different blocks from the same cases (75%). However using continuous AQUA scores, agreement between AQUA and pathologist was far lower and between slides from different blocks from the same cases only 19%. Within individual slides there was also significant heterogeneity in a scattered pattern, most notably for slides with the highest AQUA scores. In sum, using a quantitative measure of ER expression, significant block-to-block heterogeneity was found in 81% of cases. These results most likely reflect both laboratory-based variability due to lack of standardization of immunohistochemistry and true biological heterogeneity. It is also likely to be dependent on the biomarker analyzed and suggests further studies should be carried out to determine how these findings may affect clinical decision-making processes.     

Short- and long-term outcome after lung resection for invasive pulmonary aspergillosis

BACKGROUND: Lung resection for invasive pulmonary aspergillosis (IPA) is controversial. Neutropenia, thrombopenia and poor general condition may increase perioperative morbidity and mortality, and the redeeming benefit is questionable. Therefore we analyzed short- and long-term outcome after lung resection for IPA. METHODS: 41 patients with hematological disease underwent lung resection for suspected IPA: lobectomy (23 patients), wedge-resection (16) and enucleation (2). RESULTS: 4 (10%) patients developed major complications: pleural aspergillosis, bronchial stump insufficiency, severe bleeding, ARDS. 11 (27%) patients showed minor complications: pleural effusion (6), pneumothorax (2), seroma (2) and hematothorax (1). 30-day mortality was 10 % (4 of 41 patients): two died of bacterial septicemia, two of disseminated aspergillosis. One (2%) death was possibly surgery-related. IPA was cleared in 87% of patients, fungal relapse occurred in 4 (10%) patients. Overall survival was 65%, 58% and 40% at 6 months, 12 months and 5 years. CONCLUSION: Lung resection for IPA even in profound cytopenia is feasible with acceptable morbidity and mortality. Fungal infection can be cured in more than 80 % of patients. Long-term outcome can be achieved if the hematological disease is under control.     

Combined Abdominal Aortic Aneurysm Repair and Coronary Artery Bypass: Presentation of 13 Cases and Review of the Literature

Coronary artery disease remains the major cause of perioperative mortality after abdominal aortic aneurysm (AAA) repair. The beneficial effect of coronary artery bypass (CAB) before AAA repair in patients with severe coronary artery disease has been proven. The coexistence of a very large or symptomatic AAA and coronary artery disease remains a therapeutic challenge since there is the risk of AAA rupture in the interval between CAB and AAA repair. Combined CAB and aortic aneurysm repair has been suggested for these cases, and results on several series of patients have been published. However, the exact indication for the combined operation remains to be clarified. We present a series of 13 patients who underwent CAB on cardiopulmonary bypass and aortic aneurysm repair as a one-stage procedure. The indication was a large AAA in seven patients and a symptomatic AAA in six patients. In four patients, the aortic reconstruction was performed without the use of cardiopulmonary bypass; in nine patients, the aortic reconstruction was performed under partial cardiopulmonary bypass. Thirty-day mortality was 15%. Major morbidity was 31%. All major complications were due to excessive bleeding and occurred in patients who had AAA repair performed with partial cardiopulmonary bypass, suggesting that prolonged bypass time represents a major source of morbidity. A detailed review of the literature is presented. From the evidence available we suggest that the combined procedure can be recommended only for patients with very high rupture risk, such as in symptomatic AAA. In all other cases, the staged approach — CAB followed by AAA repair 2-4 weeks later — is preferable. During the combined procedure, cardiopulmonary bypass support during AAA repair should be used only in patients with clear evidence of hemodynamic instability.     

Attenuation of lipopolysaccharide-induced hyperreactivity of human internal mammary arteries by melatonin

Reactive oxygen species (ROS) are thought to be important mediators in ischaemia/reperfusion injury following coronary vasospasm. The most ubiquitous action of melatonin is that of a free radical scavenger. Therefore, we investigated the action of melatonin by monitoring changes in the tone on ring preparations from human internal mammary arteries (IMA). In quiescent IMA rings melatonin (0.1 nm-10 microm) never elicited any change in baseline tension but 1-100 nm melatonin enhanced significantly maximal responses to noradrenaline (NA) in arteries with endothelial function. In NA (1 microm) precontracted arteries inhibition of nitric oxide (NO(*)) formation by N(G)-monomethyl-L-arginine (l-NMMA, 100 and 400 microm) eliminated 43 +/- 7 and 61 +/- 7% of the acetylcholine (ACH) effect. Melatonin (100 and 400 nm) attenuated maximal endothelium-dependent relaxant responses to ACH slightly by 23 +/- 9 and 17 +/- 9% leaving responses to direct stimulation of soluble guanylate cyclase by sodium nitroprusside unchanged. Incubation of IMA for 20 hr at 37 degrees C with 1 microg/mL lipopolysaccharide (LPS) enhanced maximal NA effects to 147 +/- 18% (n = 22, P < 0.01) whereas 50 microg/mL LPS reduced the NA maxima to 68 +/- 9% (n = 10, P < 0.01) of the control effects. The LPS-induced potentiation was completely attenuated by coincubation with melatonin (400 nm) and significantly reduced by coincubation with the thromboxane synthase inhibitor dazoxiben (10 microm). It is suggested that the LPS-induced hyperreactivity of vascular smooth muscle is mediated through enhanced release of ROS and prostanoids and that melatonin inhibits the vascular hyperreactivity through selective scavenging of ROS.