Free and complexed anti-lipoprotein antibodies in vascular diseases

The cell-mediated immune response against low density lipoproteins (LDL) was demonstrated by the migration inhibition test in patients with various vascular diseases. Anti-high density lipoprotein2 (HDL2) cellular immune response was found only in a few patients. LDL and HDL2 binding factors were detected in about 50% of coronary patients. No significant difference in their occurrence was found between the normolipidemic and hyperlipidemic patients nor between patients with hyperlipidemia type II/b and type IV. On the assumption that lipoproteins may act as auto-antigens by forming immune complexes, the presence of anti-LDL and anti-HDL2 activity was investigated in circulating immune complexes obtained by polyethylene glycol (PEG) precipitation from the sera of coronary patients and controls. Using an ELISA technique, PEG-precipitable anti-LDL activity was detected in 23, 11 and 18% of cases with myocardial infarction, angina pectoris and healthy old subjects, respectively. In the immune complexes obtained from the sera of the healthy young donors no anti-LDL activity was found. Anti-HDL2 activity in the immune complexes was demonstrated only in a few cases from among the patients and elderly persons we investigated.     

Katamnestische Erhebungen bei Patienten mit Hodenhochstand

Ohne Zusammenfassung     

Percutaneous transluminal angioplasty: importance of anticoagulant and fibrinolytic drugs

At the Medical University of Pécs, Hungary, percutaneous transluminal angioplasty was performed on 252 lesions in 235 patients. Primary success rate was 75%. Long femoral artery occlusions were recanalized with a 66% patency rate in lesions 10-20 cm long and a 47% patency rate in lesions longer than 20 cm. These relatively high patency rates were attributed to the use of SP 54, a fibrinolytic agent. In a group of 52 patients treated with SP 54 there were only four reocclusions, two of these occurring 12 months after angioplasty when SP 54 was discontinued. It was concluded that long occlusions may be amenable to angioplasty provided that appropriate fibrinolytic therapy is instituted after the procedure.     

The novel red-fluorescent probe DAR-4M measures reactive nitrogen species rather than NO

INTRODUCTION: Several fluorescent probes were designed for the measurement of nitric oxide (NO), however, questions arose regarding their specificity and sensitivity in biological samples. In the present study we tested the reaction of a novel rhodamine-based chromophore diaminorhodamine-4M (DAR-4M) with NO and other reactive nitrogen and oxygen species. METHODS: We performed fluorometry in 96-well plates in a cell-free buffer with similar ion concentrations as the cytoplasm. Dose-response curves were generated using various NO donors and reactive nitrogen and oxygen species. The effects were compared between the red-fluorescent DAR-4M and its green-fluorescent counterpart 4-amino-5-methylamino-2',7'-difluorofluorescein (DAF-FM). RESULTS: DAR-4M had a markedly higher fluorescence yield to NO donors than DAF-FM, while both probes had a comparable threshold of sensitivity (in the range of 0.1 mM nitroprusside). Both dyes reacted with various NO donors in a dose-dependent manner, while superoxide, hydrogen peroxide, peroxynitrite, or nitroxyl failed to change the fluorescence intensity of the probes. DAR-4M was potentiated in the presence of peroxynitrite to react with low levels of NO donors in a similar manner to DAF-FM. DISCUSSION: We conclude that DAR-4M is a suitable red-fluorescent probe for the qualitative assessment of reactive nitrogen species production, but not specific for NO. Quantitative comparisons among samples is inappropriate since the fluorescent yield is affected by the presence of other oxidants in the sample.     

Terbutaline increases the cervical resistance of the pregnant rat in vitro

Cervical ripening is a crucial process leading to delivery. Early dilation of the pregnant cervix can contribute to premature labour. The maturity of the cervix can be characterized by its resistance to mechanical stretching. Although a number of compounds are considered to increase cervical resistance (e.g., progesterone, nitric oxide synthase inhibitors and nonsteroidal anti-inflammatory drugs), none of them seem to be safe for clinical application. Other compounds, such as ₂-adrenergic receptor (₂-AR) agonists, have been used for several decades to stop premature myometrium contractions, but their cervical action has never been investigated. The aim of this study was to detect the effects of the ₂-AR agonist terbutaline on nonpregnant and late-pregnant (day 18, 20, 21 or 22) cervices isolated from Sprague–Dawley rats. Cervical resistance was measured by means of a mechanical stretching test in vitro, the ₂-AR density was determined by Western blot analysis, the ₂-AR mRNA was determined by RT-PCR, while the G-protein activation following cervical ₂-AR stimulation with terbutaline was evaluated via a [³⁵S]GTPS binding assay.Terbutaline at 10^–6 M increased the cervical resistance of the late-pregnant samples in vitro from day18 to day 22, but did not alter the resistance of the nonpregnant samples. This cervical resistance-increasing effect was concentration dependent and antagonized with propranolol on day 21. Terbutaline was ineffective on cervical samples when gradual stretching was omitted. RT-PCR and Western blot studies revealed increased ₂-AR mRNA and ₂-AR levels respectively on day 18 of pregnancy compared with the nonpregnant cervix, but no further changes were detected up to the end of pregnancy. The [³⁵S]GTPS binding assay demonstrated a decreased G-protein activation on the days of pregnancy investigated, but no activation was found in the nonpregnant samples. The degree of decrease in G-protein activation by terbutaline was in harmony with its cervical resistance-increasing action. On day 21, the G-protein activation-decreasing effect of terbutaline was antagonized with propranolol.We presume that the cervical resistance-increasing effect of terbutaline is a consequence of its G-protein activation-decreasing property via ₂-ARs, which finally leads to an increased muscle resistance against mechanical stretching. This action of terbutaline seems unique among the smooth muscles, and may open up a new perspective in the prevention of premature labour. Clinical experience indicates that ₂-AR agonists will not be sufficient to stop the overall process, but their combination with more potent inhibitors of uterine contractions may be of clinical benefit.     

Protection against group A streptococcal infection by vaccination with self-adjuvanting lipid core M protein peptides

We have investigated the lipid polylysine core peptide (LCP) system as a self-adjuvanting group A streptococcal (GAS) vaccine delivery approach. LCP constructs were synthesised incorporating peptides from the M protein conserved carboxy terminal C-repeat region, the amino terminal type-specific region and from both of these regions. Immunisation with the constructs without adjuvant led to the induction of peptide-specific serum IgG antibody responses, heterologous opsonic antibodies, and complete protection from GAS infection. These data indicate that protective immunity to GAS infection can be evoked using the self-adjuvanting LCP system, and point to the potential application of this system in human mucosal GAS vaccine development.