Autonomic Nervous System-Controlled Cardiac Pacing: A Comparison Between Intracardiac Impedance Signal and Muscle Sympathetic Nerve Activity

BINGGELI, C., et al. : Autonomic Nervous System‐Controlled Cardiac Pacing: A Comparison Between Intracardiac Impedance Signal and and Muscle Sympathetic Nerve Activity. A recently introduced rate responsive cardiac pacing system is based on information derived from the intracardiac impedance signal containing information on the inotropic state of the ventricle. This study compared the inotropic state index (ISI) with muscle sympathetic activity (MSA), both being modulated by the autonomic nervous system. Nine patients (66 ± 3 years, mean ± SEM ) with Inos2DR pacemakers were included. Each patient was studied at rest and during cold pressor test (CPT). Microneurography of the peroneal nerve was performed to measure MSA continuously, which was digitally stored along with continuous surface ECG and blood pressure. The intracardiac impedance signal was transmitted by the pacemaker and stored simultaneously. Linear correlation between ISI and MSA was calculated for the period of the CPT. During CPT, mean systolic blood pressure increased from 122 ± 4 to 149 ± 6 mmHg (P < 0.0001), diastolic blood pressure increased from 74 ± 8 to 86 ± 4 mmHg (P = 0.02 ), and intrinsic heart rate increased from 69 ± 7 to 75 ± 7 beats/mill (P = 0.019 ). ISI increased by 21 ± 7% (P = 0.018 ), MSA by 26 ± 6% (P = 0.004 ). ISI and MSA were positively correlated during the CPT in eight of nine patients (R2 = 0.86–0.99, P < 0.0001 ). Negative correlation was found in one patient (R2 = 0.94 ). This study demonstrates parallel increases of the ISI and MSA during CPT. ISI and MSA showed a close linear relationship during provoked changes of sympathetic activity. These results provide further evidence that the sympathetic nervous system is responsible for the observed ISI changes.     

ACCESSORY MAMMARY TISSUE ASSOCIATED WITH CONGENITAL AND HEREDITARY NEPHROURINARY MALFORMATIONS

Background and Objectives. The association between polythelia (supernumerary nipple) and kidney and urinary tract malformations (KUTM) is controversial. Some authors reported this association in newborns and infants. Case-control studies dealing with adult subjects are not found in the literature. The purpose of this study is to determine the frequency of the association between accessory mammary tissue (AMT) and congenital and hereditary nephrourinary defects in an adult population compared to a control group. Methods. The study was performed in 146 white patients (123 men, 23 women) with AMT out of 2645 subjects consecutively referred to us for physical examination. The following investigations were undertaken: ultrasonographic examination of the abdomen and the kidneys, ECG, echocardiogram, roentgenogram of the vertebral column, urinalysis, and other laboratory tests. A sex- and age-matched control group without any evidence of AMT or lateral displacement of the nipples underwent the same examinations. Results. Kidney and urinary tract malformations were detected in 11 patients with AMT (nine men, two women) and in one control. These data indicate a significantly higher frequency of KUTM in the AMT-affected patients compared to controls (7.53% vs. 0.68%, P < 0.001). A broad spectrum of KUTM was discovered in association with AMT: adult dominant polycystic kidney disease, unilateral renal agenesis, cystic renal dysplasia, familial renal cysts, and congenital stenosis of the pyeloureteral joint. Conclusion. Accessory mammary tissue offers an important clue for congenital and hereditary anomalies of the kidneys and urinary collecting systems. Patients with AMT should, therefore, be extensively examined for the presence of occult nephrouropathies.     

Coexpression of CD69 and HLADR activation markers on synovial fluid T lymphocytes of patients affected by rheumatoid arthritis: a three-colour cytometric analysis.

The aim of the present study was to evaluate the coexpression of very early (CD69), early (CD25) and late (HLADR) antigens and to analyse the mean fluorescence intensity (MFI) of such activation markers on synovial fluid (SF) and peripheral blood (PB) lymphocytes of patients affected by rheumatoid arthritis (RA) and other types of chronic synovitis (OCS). A three colour cytometric analysis was performed using a peridinin chlorophyll protein conjugated anti-CD3 antibody in combination with fluorescein isothiocyanate or phycoerythrin labelled anti-CD69, anti-HLADR, anti-CD25 monoclonal antibodies (mAbs). A T cell gating method was utilized, so that three sets of bivariant dot plot quadrant displays were obtained (CD69/HLADR, CD69/CD25, CD25/HLADR). A large percentage of SF T lymphocytes in RA showed the coexpression of very early and late activation antigens (CD3 + CD69 + HLADR +), whereas CD3 + CD69 + CD25 + bearing cells and CD3 + CD25 + HLADR + lymphocytes were only a small percentage. Similar results were obtained in patients with OCS, although to a lesser extent. No statistically significant differences in MFI of CD69 and HLADR positive SF T cells between RA and OCS were observed. The CD69 + CD25-HLADR + T cell subset is the most commonly represented in the synovial environment, among those we have evaluated; this phenotype may be characteristic of chronic inflammatory arthritis.     

DIFFERENTIAL NEURAL CREST CELL ATTACHMENT AND MIGRATION ON AVIAN LAMININ ISOFORMS

A number of laminin isoforms have recently been identified and proposed to exert different functions during embryonic development. In the present study, we describe the purification and partial characterization of several isoforms isolated from chick heart and gizzard, and provide data on the molecular mechanisms underlying the interaction of avian neural crest cells with these molecules in vitro. Laminins extracted from heart and gizzard tissues were separated by gel filtration and purified to homogeneity by sequential lectin and immunoaffinity chromatography by utilizing monoclonal antibodies directed against the avian α2, β2 and γ1 laminin chains. The sodium dodecyl sulfate—polyacrylamide gel electrophoresis (SDS—PAGE) banding pattern of the polypeptide complexes obtained and immunoblotting with polyclonal antisera allowed the identification of Laminin-2 (α2β1γ1), Laminin-4 (α2β2γ1), and laminins comprising the β1, β2 and γ1 chains associated with a shorter α chain which, in SDS—PAGE, co-migrate with the β/γ complex in the 200 kDa region. These latter laminins, which are here arbitrarily denoted Laminin-αχ (heart tissue) and Laminin-G (gizzard tissue), are somewhat distinct in their apparent molecular weight, are differentially associated with nidogen, and appear as “T”-shaped particles similar to Laminin-6 and Laminin-7 when analyzed by transmission electron microscopy following rotary shadowing. In contrast, the avian Laminin-2 and Laminin-4 isoforms exhibit the characteristic cruciform shape described previously for their mammalian counterparts. Isolated neural crest cells differentially attached and migrated on these laminin isoforms, showing a clear preference for Laminin-G. Similarly to the EHS Laminin-1, neural crest cells recognized all avian isoforms through their α1β1 integrin, shown previously to be the primary laminin-binding receptor on these cells. Neural crest cell interaction with the avian laminins was dependent upon maintenance of the secondary and tertiary structure of the molecules, as shown by the marked reduction in cell attachment and migration upon disruption of the α-helical coiled-coil structure of their constituent chains. The results demonstrate that different laminin isoforms may be differentially involved in the regulation of neural crest cell migration and suggest that this regulation operates through interaction of the cells with a structurally conserved cell binding site recognized by the α1β1 integrin. Copyright © 1996. Published by Elsevier Science Ltd.     

Propafenone Induced Acute Variation of Chronic Atrial Pacing Threshold: A Case Report

A marked increase of chronic atrial pacing threshold resulting in loss of atrial capture, induced by propafenone, is reported in a patient with bradycardia-tachycardia syndrome. After atrial pacemaker implant, the atrial threshold had been measured repeatedly noninvasively and shown to be stable. The threshold rise and loss of atrial capture occurred after 7 days of treatment with propafenone at the dosage of 450 mg daily; drug withdrawal resulted in resumption of atrial capture and a return to prior pacing thresholds.     

PROLACTIN STIMULATION BY INTRAVENOUS LABETALOL IS MEDIATED INSIDE THE CENTRAL NERVOUS SYSTEM

We have previously reported that labetalol infusion increases prolactin (PRL) secretion in hypertensive patients. In an attempt to investigate the site where labetalol stimulates PRL, the drug was infused intravenously (100 mg) into healthy subjects, both under basal conditions and after pretreatment with l -dopa plus carbidopa (250 mg and 25 mg respectively every 6 h for 1 day), since this regimen has been reported to blunt the PRL responses to centrally acting stimuli. The effects of oral labetalol administration (100 and 200 mg) on PRL was also evaluated. Serum PRL concentration did not change after oral labetalol, whereas it was increased by intravenous drug administration. This effect was completely abolished by pretreatment with l -dopa plus carbidopa. These findings, though they do not demonstrate the mechanism, suggest that the hyperprolactinaemia induced by labetalol is mediated inside the blood–brain barrier.