Multiprogrammable pacemakers. Complications. Nursing care

This paper deals with the study of 927 patients of both sexes, with multiprogramable pacemakers implanted during 1987-1988 period, at the "Comandante Manuel Fajardo" Teaching Hospital and the Institute of Cardiology and Cardiovascular Surgery. Complications accounted for 14.9% and the most frequent were, in decreasing order, as follows: sepsis of the pocket (46.7%), hematoma of the pocket, increased threshold and, in a lower percentage, aseptic necrosis (5.7%). Emphasis is made in the role of the nurse in front of a patient with pacemaker and of the different complications presented.     

Characterization of the muscarinic receptor subtype(s) mediating contraction of the guinea-pig lung strip and inhibition of acetylcholine release in the guinea-pig trachea with the selective muscarinic receptor antagonist tripitramine

1. The muscarinic receptor subtypes mediating contraction of the guinea-pig lung strip and inhibition of the release of acetylcholine from cholinergic vagus nerve endings in the guinea-pig trachea in vitro have previously been characterized as M₂-like, i.e. having antagonist affinity profiles that are qualitatively similar but quantitatively dissimilar compared to cardiac M₂ receptors. The present study sought to establish definitely the identity of these receptor subtypes by using the selective muscarinic receptor antagonist, tripitramine. Guinea-pig atria and guinea-pig trachea (postjunctional contractile response) were included for reference.
2. It was found that tripitramine antagonized methacholine-induced contractions of the guinea-pig lung strip with a pK_B value of 8.76±0.05. Both the parallel shifts of the concentration-response curves and the slope of the Schild plot being not significantly different from unity (when antagonist preincubation was for 2 h) indicated the involvement of a single population of receptors in the contractile response. From the pK_B values obtained with tripitramine and a range of other selective muscarinic receptor antagonists (cf. Roffel et al., 1993), this single population of receptors can only be classified as M₂-like.
3. Tripitramine antagonized methacholine-induced negative chronotropic and inotropic responses in guinea-pig right and left atria with apparent pK_B values of 9.4–9.6. However, such values were only obtained when antagonist preincubation was relatively long and/or antagonist concentration relatively high (e.g. with 1 h at 100 or 300 nM but 3 h at 30 nM). It thus appears that low concentrations of tripitramine do not readily equilibrate with M₂ receptors in guinea-pig atria nor with M₂-like receptors in the guinea-pig lung strip.
4. Tripitramine increased electrical field stimulation-induced cholinergic twitch contractions in guinea-pig trachea in concentrations of 0.3–100 nM, by blocking prejunctional muscarinic inhibitory autoreceptors; with higher concentrations, twitch contractions were progressively diminished, as a result of blocking postjunctional M₃ receptors (apparent pK_B value 6.07±0.15). The pEC₂₀ value (−log concentration that increases twitch by 20% of maximum) was 8.29±0.08, which would suggest that M₄ receptors are involved in this response.
5. Oxotremorine-induced inhibition of the release of prelabelled [³H]-acetylcholine from guinea-pig trachea, under conditions where there is no auto-feedback, was blocked by tripitramine (2 h preincubation) with a pK_B value of 8.56±0.06. The slope of the corresponding Schild plot was not significantly different from unity, which together with the parallel shifts of the concentration-response curves indicated the involvement of a single muscarinic receptor subtype.
6. Since the pK_B value for tripitramine at prejunctional receptors in guinea-pig trachea is in between the affinities towards M₂ and M₄ receptors, correlation plots were constructed to compare the pK_B values obtained with tripitramine and a range of other selective muscarinic receptor antagonists (cf. Kilbinger et al., 1995) to reported affinities at M₁–M₄ receptors. This showed rather similar distribution patterns of the data points around the line of equality in the case of M₂ and M₄ receptor subtypes. However, the correlation coefficient was markedly better for M₂ (0.9667) than for M₄ (0.5976). Since recent evidence suggests that M₄ receptors are not expressed in cholinergic nerves from guinea-pig trachea, it is concluded that prejunctional muscarinic autoinhibitory receptors in this tissue exhibit an atypical M₂ type character, with a pharmacological profile distinct from cardiac M₂ receptors.

     

The use of the STRs HUMTH01, HUMVWA31/A,HUMF13A1, HUMFES/FPS,HUMLPL in forensic application: Validation studies and population data for Galicia (NW Spain)

The 5 tetranucleotide short tandem repeats, HUMTHOI, HUMVWA31/A, HUMF13A1, HUMFES/FPS and HUMLPL were studied using different electrophoretic methods and PCR amplification conditions in order to optimize the typing conditions. A genetic population study in the population of Galicia was carried out and the allele and genotype frequencies are given. Compliance with the Hardy-Weinberg equilibrium was tested using different statistical parameters, with clear advantages resulting in favor of using the exact test (Guo-Thompson method) instead of conventional chi-square methods. Some statistical parameters of forensic interest (PD, CE, h) were also calculated. There were no mutations found in a total of 73 paternal meioses and 101 maternal meioses. Abnormal electrophoretic mobility was found in the AT-rich STR HUMF13AI under non-denaturing conditions and, therefore, the use of denaturing conditions is absolutely necessary. No "stutter" bands were found, although double peaks in the HUMFES/FPS system were observed in some samples. The advantage of using automated sequencers with fluorescent technology is also reported.     

Interaction of ivermectin with γ-aminobutyric acid receptors in Trichinella spiralis muscle larvae

The value of the γ-aminobutyric acid (GABA) receptor of nematodes as a target for ivermectin's mode of action remains unclear. Using binding assays, we examined extracts from Trichinella spiralis muscle larvae for the presence of [³H]-ivermectin and [³H]-GABA binding sites. Tissue preparations displayed affinity binding sites for [³H]-ivermectin with a dissociation constant (K _d) of 83 nM and a receptor density (B_max) of 145 fmol/mg protein. We also identified a specific [³H]-GABA binding activity with a K _d of 1.2 μM and a B_max of 4.78 pmol/mg protein. In competition studies, ivermectin was found to be a competitive inhibitor of specific [³H]-GABA binding activity with an inhibition constant (K _i) of 3.39 nM, suggesting that GABA receptors could be implicated in the mechanism of action of ivermectin in nematodes. Received: 7 August 1998 / Accepted: 22 September 1998