Inappropriate Management of Self-Terminating Ventricular Arrhythmias by Implantable Cardioverter Defibrillators Despite a Specific Reconfirmation Algorithm: A Report of Two Cases

Algorithms that attempt to reconfirm the presence of an arrhythmia prior to definite treatment have been implemented in ICDs to prevent inappropriate shock therapy due to self-terminating ventricular arrhythmias. Nevertheless, in two patients, clinically inappropriate shocks were delivered after spontaneous conversion of the arrhythmia despite the use of a specific reconfirmation algorithm. Reconfirmation criteria were met due to a premature ventricular complex causing a short cycle in the first patient and a long postextrasystolic pause in the second patient. To avoid inappropriate shock therapy due to self-terminating ventricular arrhythmias, further improvement of detection algorithms is required. (PACE 1997; 20[Pt. I]:1328-1331)     

Adsorption of iron to saliva coated hydroxyapatite

Abstract – Saliva coated hydroxyapatite was used as a model to study iron adsorption to pellicle material. The uptake of iron was markedly influenced by its concentration in the medium. Denaturation of the protein film by chlorhexidine, tannic acid, or heating up to 70°C increased the adsorption significantly.     

Histologic characteristics of clinically healthy gingiva in adolescents

Abstract – Gingival biopsies from healthy buccal gingival units in 10 young individuals (12–14 yr) were analyzed morphometrically. The connective tissue was generally characterized by a dense collagenous network, apart from a well defined zone subjacent to the smooth and noninfiltrated juncdonal epithelium. This zone, which constituted on average 10%, of the connective tissue volume, was less dense than the remaining part of the connective tissue and devoid of well defined collagen fiber bundles. This zone could also harbor clusters of infiammatory cells, mainly mononuclear cells, surrounded by non-infiltrated collagen-poor connective tissue, in the noninfiltrated collagen-dense mid-portion of the gingival connective tissue small areas of infiltrates could be found, the composition of which resembled that of the infiltrated areas subjacent to the junctional epithehum.     

Permeability of different lining materials

abstract — The permeability of four dental lining materials has been tested by water vapor penetration in vitro . Films of Dycal® and Copalite® were found to have low permeability values while rather great permeability was found for test specimens of Dropsin® and Tubulitec®.     

Experimental gingivitis in young dogs

abstract — The aim of the present study was to analyze and express in quantitative terms some of the structural alterations which develop in an initially normal gingiva during a phase of continuous plaque accumulation. Four beagle dogs were used. The animals had from birth been twice daily subjected to meticulous mechanical tooth cleaning. When the dogs were 10 months of age their gingiva were in excellent health as evaluated by Gingival Index and Gingival Exudate measurements. Gingival tissues were harvested from the premolar and molar regions in the right jaws. The tooth cleanings were then terminated and plaque allowed to accumulate. Clinical examinations were performed and gingival biopsies sampled after 4, 7, 14, 21 and 28 d. The composition of the gingival biopsies was analyzed in a sampling microscope. After 4 d of plaque accumulation significant amounts of gingival exudate could be sampled. The exudation then gradually increased during the following weeks. Biopsies representing day zero did not contain any inflammatory cell infiltrates. However, after 4 d of the experiment leukocytes were found in the collagen-poor connective tissue immediately beneath the junctional epithelium. The size of the infiltrated connective tissue (ICT) gradually increased during the experiment. The volumetric density of collagen in the noninfiltrated connective tissue (NCT) was always much higher than in ICT. In ICT, however, this density parameter remained rather constant throughout the study. On days 4 and 7 neutrophilic granulocytes constituted 60–70% of the leukocyte population. On day 28, however, the infiltrate comprised mainly mononuclear leukocytes, especially plasma cells, neutrophils at that time occupying only a small fraction of the infiltrate.     

IN-SITU CHARACTERIZATION OF MONONUCLEAR CELL INFILTRATES IN LESIONS OF MULTIPLE SCLEROSIS

Nyland H, Mork S & Matre R.1982 Neuropathology and Applied Neurobiology 8, 403–411
In-situ characterization of mononuclear cell infiltrates in lesions of multiple sclerosis
The mononuclear cell infiltrates in autopsy material from brains and spinal cords of six patients with multiple sclerosis (MS) were characterized in situ. Receptors for sheep erythrocytes and anti-T lymphocyte serum were used to identify T lymphocytes. Receptors for the activated third components of complement and for the Fc-portion of IgG (Fey receptors) were used as markers for macrophages and lymphocytes. In acute and recent MS lesions, perivascular infiltrates of mononuclear cells were commonly found. Most cells were T lymphocytes. Some B lymphocytes were also demonstrated. The demyelinating lesions contained large numbers of lipid macrophages expressing Fey receptors. The lipid macrophages are probably derived from microglial cells. The chronic, demyelinated lesions contain a few mononuclear cells, mainly B lymphocytes and plasma cells.