Canadian Registry of ICD Implant Testing Procedures (CREDIT): Current Practice,Risks, and Costs of Intraoperative Defibrillation Testing

Defibrillation Testing at ICD Implantation. Background: There is uncertainty about the proper role of defibrillation testing (DT) at the time of implantable cardioverter defibrillator (ICD) insertion. Methods: A prospective registry was conducted at 13 sites in Canada between January 2006 and October 2007. Objectives: To document the details of DT, the reasons for not conducting DT, and the costs and complications associated with DT. Results: DT was conducted at implantation in 230 of 361 patients (64%). DT was more likely to be conducted for new implants compared with impulse generator replacements (71% vs 32%, P = 0.0001), but was similar for primary and secondary prevention indications (64% vs 63%, P = NS). Among patients not having DT, the reason(s) given were: considered unnecessary (44%); considered unsafe, mainly due to persistent atrial fibrillation (37%); lack of an anesthetist (20%); and, patient or physician preference (6%). When performed, DT consisted of a single successful shock ≥ 10J below maximum device output in 65% of cases. A 10J safety‐margin was met by 97% of patients, requiring system modification in 2.3%. Major perioperative complications occurred in 4.4% of patients having DT versus 6.6% of patients not having DT (P = NS). ICD insertion was $844 more expensive for patients having DT (P = 0.16), largely due to increased costs ($28,017 vs $24,545) among patients having impulse generator replacement (P = 0.02). Conclusions: DT was not performed in a third of ICD implants, usually due to a perceived lack of need or relative contraindication. (J Cardiovasc Electrophysiol, Vol. 21, pp. 177‐182, February 2010)     

Inhibition of melatonin secretion onset by low levels of illumination

Melatonin is a hormone released during darkness under the control of the hypothalamic circadian pacemaker. It has been shown that melatonin is suppressed by light as a function of intensity, with low levels of illumination producing small effects and more intense light greater, but not complete inhibition. The studies which lead to these conclusions administered light subsequent to the secretion pattern being well established. Light as low as 250 lux administered during the normal onset of secretion can reduce melatonin to below detectable levels. The onset of melatonin secretion was delayed for at least an hour during 250 lux exposure and did not rise until termination of light exposure (two hours after control melatonin onset) with higher illumination (500, 1000 and 2500 lux). This tentatively indicates that duration of the inhibition is intensity dependent. It is suggested that the experimental paradigm used in the present study may be a more realistic representation of the effect of normal light exposure (both natural and artificial) on the circadian system, and that findings may be pertinent to the aetiology of certain sleep onset insomnias, which would include delayed sleep phase syndrome (DSPS) and adaptation to shift work.     

Cutaneous Effects of Cryogen Spray Cooling on In Vivo Human Skin

BACKGROUND: Despite widespread clinical use of cryogen spray cooling (CSC) in conjunction with laser dermatologic surgery, in vivo cutaneous effects have not been systematically evaluated. OBJECTIVE: The authors characterize the in vivo cutaneous effects for Fitzpatrick skin types I through VI after CSC exposures of varying spurt durations and spurt delivery patterns (single vs. multiple spurts). MATERIALS AND METHODS: Twenty-seven normal human subjects were exposed to single cryogen spurts from 10 to 80 milliseconds, and multiple spurt patterns consisting of two 20-millisecond spurts, four 10-millisecond spurts, and eight 5-millisecond spurts. Subjects were evaluated by clinical observation and photography at 1 hour, 1 day, and 1, 4, 8, and 12 weeks after CSC exposure. RESULTS: Acute erythema and urticaria (1-24 hours) were noted in 14 of 27 and 3 of 27 subjects, respectively. Transient hyperpigmentation occurred in 4 of 27 subjects (skin types III-VI) but resolved spontaneously without medical intervention in all subjects by 8 weeks. No permanent skin changes were noted in any subjects. Skin reactions were more common with longer single-spurt durations (50 milliseconds or greater) and multiple spurt patterns. CONCLUSION: Acute erythema, urticaria, and, less commonly, transient hyperpigmentation were observed after CSC exposure. Permanent skin injury was not observed and is unlikely.     

Antinuclear antibodies using HEp-2 cells in normal children and in children with common infections

Antinuclear antibody (ANA) immunofluorescence tests, using HEp-2 cells, were performed on 100 children without a history of connective tissue disease. Eighteen (18%) were positive at titres greater than or equal to 1:40, nine (9%) being greater than 1:160. Interlaboratory variability was demonstrated with some specimens. No association with possible intercurrent infection was found to account for positive results. Of 44 children with proven infections five (11%) were positive. Antinuclear antibody may be found in some normal children when using the sensitive HEp-2 cell substrate, and in the absence of clinical features should not necessarily suggest the presence of a connective tissue disease.     

Inhibition of binding of phospholipase Cγ1 SH2 domains to phosphorylated epidermal growth factor receptor by phosphorylated peptides

A series of tyrosine-containing peptides 1–12: Asp-Ala-Asp-Glu-Tyr⁹⁹²(PO₃H₂)-Leu-Ile-Pro-Gln-Gln-Gly-OH (1) Asp-Ala-Asp-Glu-Tyr⁹⁹² -Leu-Ile-Pro-Gln-Gln-Gly-OH (2) Phe-Leu-Pro-Val-Pro-Glu-Tyr¹⁰⁶⁸(PO₃H₂)-Ile-Asn-Gln-Ser-Val-OH (3) Phe-Leu-Pro-Val-Pro-Glu-Tyr¹⁰⁶⁸ -Ile-Asn-Gln-Ser-Val-OH (4) Asp-Asn-Pro-Asp-Tyr¹¹⁴⁸JR(PO₃H₂)-Gln-Gln-Asp-Phe-Phe-OH (5) Asp-Asn-Pro-Asp-Tyr¹¹⁴⁸ -Gln-Gln-Asp-Phe-Phe-OH (6) Ala-Glu-Tyr¹¹⁷³(PO₃H₂)-Leu-Arg-Val-Ala-Pro-Gln-Ser-OH (7) Ala-Glu-Tyr¹¹⁷³ -Leu-Arg-Val-Ala-Pro-Gln-Ser-OH (8) Ala-Glu-Tyr¹¹⁷³(PO₃H₂)-Leu-Arg-Val-Ala-OH (9) Ala-Glu-Tyr¹¹⁷³ -Leu-Arg-Val-Ala-OH (10) Tyrl¹¹⁷³(PO₃H₂)-Leu-Arg-Val-Ala-Pro-Gln-Ser-OH (11) Tyr¹¹⁷³ -Leu-Arg-Val-Ala-Pro-Gln-Ser-OH (12) (six pairs with and without the tyrosine phosphorylated) has been synthesized. The peptides were derived from tyrosine autophosphorylation sites in the epidermal growth factor receptor (EGFR): Tyr 992, 1068, 1148 and 1173. Peptide 1, derived from the Tyr 992 site, inhibited binding of a ³⁵S-labelled fusion protein containing both of the SH2 domains from PLCγ1 to the phosphorylated EGFR with an IC₅₀ of 8 μM. All of the phosphorylated peptides except 11 (1, 3, 5, 7 and 9) inhibited this binding to some degree (20–55%) at 10 p μM. The nonphosphorylated peptides were inactive in this assay. The nonphosphorylated peptides 2, 4, 6, 8, 10 and 12 were obtained by standard solid-phase synthetic methodologies using both Boc/benzyl and Fmoc/tert-butyl strategies. The phosphorylated peptides 1, 3, 5, 7, 9 and 11 were similarly obtained using a Fmoc/tert-butyl strategy incorporating unprotected N^x-Fmoc-Tyr, followed by phosphitylation and oxidation of the tyrosine in the resin-bound peptide. In addition, Asp-Ala-Asp-Glu-Phe⁹⁹²(4-CH₂PO₃H₂)-Leu-Ile-Pro-Gln-Gln-Gly-OH (15), an analog of 1 incorporating an enzymatically stable phosphotyrosine mimic, 4-phosphonomethyl-l -phenylalanine, was synthesized and found to be inactive.     

Polarization Color Imaging System for On-Line Quantitative Evaluation of Facial Skin Lesions

BACKGROUND A number of studies have been performed for accurate evaluation of chromophores in skin lesions. Qualitative methods are subjective and cause user-dependent error in evaluation. Quantitative methods have limitations for widely distributed skin lesions due to poor spatial resolution, potential skin blanching, and difficulty in relocating identical sites for subsequent measurements and analysis.
OBJECTIVE The objective was to develop a new imaging modality that provides both qualitative and quantitative methods to evaluate widely distributed skin lesions.
METHODS We have developed a prototype polarization color imaging system named "DermaVision," which provides quantitative on-line image analysis of polarization color images. Herein, we describe the hardware and software of DermaVision in terms of its performance and usefulness for dermatologic applications.
RESULTS Polarization color images were successfully acquired from patients with vascular or pigmented skin lesions. The erythema and melanin index images were successfully computed and quantitatively confirmed the degree of erythema and pigmentation in the skin lesions.
CONCLUSION We believe that DermaVision can be a useful auxiliary tool in dermatology because it simultaneously provides both qualitative and quantitative images of skin lesions.