Intrapatient Comparison of Atrial and Ventricular Sensing, Pacing Threshold, and Impedance: Benefits with Steroid-Eluting Leads

We compared the atrial and ventricular bioelectrical effects relating to pacing threshold, pacing impedance, and pacing energy in each of 58 patients to determine the importance of pacing impedance in safe low energy stimulations. The study was conducted during 4 years of follow-up. Of the 58 patients in our study, 31 were stimulated in both chambers with steroid-eluting leads (Capsure 4503 and 4003) and 27 with platinum electrode catheters (Target Tip 4511 and 4011). The two groups were homogeneous in sex, age, cardiopathy, and reason for implant. At 6 months, the mean impedance values for the Target Tip were: 358 ± 72 Ω for the atrium and 443 ± 87 Ω for the ventricle (P < 0.00002): after 1 year, atrium = 386 ± 77 Ω, ventricle = 439 ± 42 Ω (P < 0.04); at 2 years, atrium = 409 ± 86 Ω, ventricle = 510 ± 94 Ω (P < 0.0001); at 3 years, atrium = 428 ± 81 Ω, ventricle = 494 ± 67 Ω (P < 0.02); and at 4 years, atrium = 424 ± 71 Ω and ventricle = 501 ± 69 Ω (P < 0.003). The mean impedance value (for the Capsure) was: atrium = 351 ± 43 Ω, ventricle = 431 ± 81 Ω at 6 months (P < 0.03); at 1 year, atrium = 359 ± 38 Ω, ventricle = 446 ± 83 Ω (P < 0.01); at 2 years, atrium = 304 ± 124 Ω, ventricle = 459 + 108 Ω (P <0.0003); at 3 years, atrium = 359 ± 108 Ω, ventricle = 461 ± 89 Ω (P < 0.02); and at 4 years, atrium = 419 ± 133 Ω and ventricle = 515 ± 75 Ω (P < 0.03;. In view of the chronic threshold, low energy stimulation was used at follow-up. The mean low energy stimulation values programmed for Target Tip were: atrium = 2.5 V/0.35 ms, ventricle = 2.5 V/0.30 ms; for Capsure, atrium = 2.5 V/0.25 ms, ventricle = 2.5 V/0.25 ms. The mean stimulation energy value was 31% higher in the atrium than in the ventricle with Capsure leads, and 39% higher with Target Tip. Pacing impedance was lower in the atrium than in the ventricle with both leads. Energy consumption in the atrium is significantly greater than in the ventricle with both leads, particularly with Target Tip.     

Atypical chronic lymphocytic leukaemia witht(ll;14)(ql3;q32): karyotype evolution and prolymphocytic transformation

Summary. In order to define better the cytological and clinical features of atypical B-cell chronic lymphocytic leukaemia (B-CLL) with t(ll;14)(ql3;q32), sequential morphologic immunological and cytogenetic studies were performed in seven patients belonging to a series of 72 consecutive cases presenting with a diagnosis of CLL or atypical CLL according to the FAB criteria. Cytologic diagnosis in these seven patients with t(ll;14) was typical CLL in two cases presenting with < 10% large lymphocytes (LL) and prolymphocytes (PL) and atypical CLL in five cases in which LL and PL comprised between 10% and 55%. The diagnosis was supported by histologic findings on bone marrow biopsy (five cases) or splenectomy specimens (two cases). A progressive increase of peripheral LL and PL was observed, resulting in a switch of FAB diagnosis over a 6-60-month period from typical CLL into atypical CLL in two cases and from atypical CLL into prolymphocytic leukaemia in five cases. Immunophenotyping showed a mature B-cell phenotype with CD19, CD22, CD24 positivity and CD10 negativity in all patients. A bright-staining pattern for surface immunoglobulins (SIg) was detected in 6/7 cases, CD5 positivity in 6/7 cases, and CD23 positivity in 1/7 cases. The FMC-7 monoclonal antibody was positive in >40% cells in 5/6 cases. Chromosome changes in addition to t(11; 14) were seen in five cases; in two cases unbalanced translocations involving the 3q21 chromosome region, resulting in partial trisomy for the long arm of chromosome 3, were detected early in the course of the disease. Karyotype evolution that was associated with disease progression occurred in 3/6 assessable patients. Comparison of these findings with similar data from 65 B-CLL patients without t(ll;14) showed that atypical morphology, switch of FAB diagnosis during the course of the disease, and karyotype evolution were more frequently seen in cases with t(ll;14) (5/7 v 15/65 cases, P = (V015, 7/7 v 7/65 cases, P < 0-0001, and 3/6 v 5/45 assessable cases, P= 0-04, respectively). The frequency of positivity for CD2 3 and bright SIg staining differed significantly in the two groups. It is concluded that t(ll;14) identifies a cytologically atypical subset of B-CLL, characterized by frequent cytologic and cytogenetic evolution and by a distinct immunological profile, sharing some biological features with mantle cell lymphoma.     

Arrhythmia Detection in Single‐ and Dual‐Chamber Implantable Cardioverter Defibrillators: The More Leads,the Better?

The implantable cardioverter defibrillator (ICD) offers life-saving therapies for primary and secondary prevention of sudden cardiac death in high-risk patients. However, ICD detection algorithms consistently misclassify a substantial proportion of supraventricular rhythms, thus carrying the risk for inappropriate therapies. Although single-chamber ICD (Sc-ICD) discrimination tools have been reported to provide high specificity in rejecting sinus tachycardia and atrial fibrillation with a relatively low ventricular rate, accurate recognition of atrial fibrillation with faster ventricular rates, atrial tachycardias, atrial flutter, and some reentrant tachycardias is still an issue. Dual-chamber ICDs (Dc-ICDs) are supposed to overcome specificity issues by enhancing detection algorithms with information derived from the atrial and ventricular timing relationship. The initial promise of Dc-ICDs was to improve detection specificity without compromising sensitivity, and to translate this advantage over Sc-ICDs in a more selective use of aggressive therapies. Despite this solid background, superiority of Dc- over Sc-ICDs has never been convincingly demonstrated. The present review focuses on the efficacy of contemporary ICD arrhythmia discrimination tools and appraises the so far reported evidence supporting the superiority of Dc-ICDs in preventing inappropriate therapies.     

Dermoscopy in Epidermodysplasia Verruciformis

BACKGROUND: Epidermodysplasia verruciformis (EV) is a rare autosomal recessive genodermatosis characterized by an impairment of cellular immunity. It clinically manifests as widespread, long-lasting, pityriasis versicolor-like macules and flat, wart-like papules, usually occurring in early childhood. There is a risk of development of multiple skin cancers in the third decade, primarily in sun-exposed skin. EV-associated human papillomaviruses have been implicated in a number of cutaneous lesions in non-EV populations, such as seborrheic keratoses or psoriasis. They have also been implicated in the development of nonmelanoma skin cancer, especially in immunosuppressed patients. Patients affected with EV are not able to eliminate oncogenic viruses within lesions, leading to a malignant transformation. OBJECTIVE: To describe the dermoscopic characteristics of EV cutaneous tumors by performing histopathologic correlation. METHODS AND MATERIALS: Cutaneous lesions and tumors from two patients affected by EV were included. Clinical and dermoscopic images were obtained and excision with ulterior histopathology was performed in all suspicious tumors and characteristic lesions. RESULTS: Dermoscopy and histology of pityiriasis versicolor-like macules, wart-like papules, seborrheic keratosis-like tumors, psoriasis-like plaques, collision tumors, and Bowen in situ carcinoma are described. CONCLUSIONS: Dermoscopy in EV tumors correlated with histopathologic findings and improved the differential diagnosis of tumors in this disease.     

ANTIBODIES AGAINST HAPTENS IN THE STUDY OF STRUCTURE AND BIOLOGICAL ACTIVITY OF GROWTH HORMONE

The α-amino group of bovine Growth Hormone was selectively modified with TNBS with no detectable changes in growth promoting activity. TNP was used as hapten for the production of antibodies against the end terminal region of bGH. The region near the α-amino group is not involved in the binding of bGH to rat liver cells, and it seems to be away from the part of the molecule that interacts with the cell binding sites.     

Conformational study of a peptide epitope shows large preferences for β-turn conformations

The conformational preferences of the 7-residue peptide Glu-Val-Val-Pro-His-Lys-Lys was investigated using a global search algorithm, namely the Electrostatically Driven Monte Carlo (EDMC) method, and the ECEPP/2 potential energy function. This particular sequence corresponds to the N-terminal portion of a 19-residue peptide antigen whose three dimensional structure, when complexed to a cognate antibody, was reported recently. As a result of this study a series of low-energy conformations were identified showing a common folding pattern with residues Val-3, Pro-4, His-5 and Lys-6 forming a β turn. A comparison of the computed conformations with the one determined by X-ray crystallography in the antibody-antigen complex reveals marked similarities. In most of the cases rms deviations smaller than 1.1 Å were found for the backbone atoms of the four residues forming the turn. These results suggest that the recognition process is accomplished in this case through the interaction of the antibody with relatively stable conformers of the antigenic peptide.     

DIFFUSE CUTANEOUS LEISHMANIASIS WITH ATYPICAL ASPECTS

A 16-year-old man had long-standing diffuse cutaneous leishmaniasis with the following characteristics: diffuse infiltrated lesions rich in amastigotes, absence of mucosal involvement, and lack of parasite-specific cell-mediated immune response. In situ identification of Leishmania mexicana amazonensis was achieved by the use of monoclonal antibodies. Clinically, as an atypical finding there was deep and extensive ulceration in the lower limbs. Histologically, an atypical characteristic was the presence of a high number of eosinophils in the infiltrate predominantly in the ulcerated lesion. Ultrastructurally, parasitized and lysed eosinophils with dispersion of their granules were seen in the vicinity of parasitized or lysed macrophages.     

Chemical modification of human growth hormone with N-acetylimidazole

The effect of acetylation of tyrosine residues on the binding capacity of human growth hormone (hGH) to rat liver lactogenic and somatogenic receptors was studied. When 3.7 tyrosine and 4.8 lysine residues were acetylated with N-acetylimidazole, both the in vivo and the in vitro capacities of hGH to compete with ¹²⁵I-labeled bovine growth hormone for somatogenic binding sites greatly decreased. Acetylation also affected the in vitro binding capacity to lactogenic sites. Most of the somatogenic binding activity was recovered by hydroxylamine treatment, which removes O-acetyl groups from tyrosine residues but not N-acetyl groups from lysine residues. The same treatment partially restored lactogenic binding capacity. The reactivity of hGH tyrosine residues to N-acetylimidazole, together with previous evidence, suggests that: (a) Tyrosine residues 160 and 164, when acetylated, are likely to be responsible for the low binding activity of acetylated hGH. (b) Tyrosine 160 may play a significant role in hGH interaction with lactogenic receptors.     

Transarterial Permanent Pacing of the Left Ventricle

Clinical evaluation of a 64-year-old male patient with a permanent pacemaker showed a right bundle branch block in his ECG that led to the suspicion of catheter misplacement. A two-dimensional echocardiogram and bilateral venogram demonstrated that the pacemaker lead was not in the venous system and that its course was from the axillary artery to the left ventricle passing through the aortic valve. Thirty-three days after implant, replacement of the pacemaker lead through the venous system to stimulate the right ventricular endocardium was performed. At 7 month follow-up the patient has had no complication from his previous arterial pacemaker implantation.