Clinical Evaluation of VDD Pacing with a Unipolar Single-Pass Lead

Twenty patients with advanced AV block and normal sinus node function underwent pacemaker implantation, randomly receiving a CPI 910 ULTRA II model VDD pacemaker. The first 13 patients received the implantation of a single lead with a screw-in positive ventricular fixation tip and a unipolar ring floating atrial electrode spaced 13 cm from the tip. A subsequent group of seven patients received a conventional porous tinned-tip lead with a pair of unipolar ring floafing electrodes. The second solution was adopted because the best atrial signal was not always in the high or mid-high atrium portion, but sometimes in the middle or mid-low position. With the modified double-electrode lead, the floating atrial electrode that detects the best signal can be selected, cutting out the pin of the one not used. The comparisons between minimal atrial slew rate and maximal ventricular slew rate, as well as those between minimal P wave amplitude and maximal R wave amplitude, show a highly significant range difference, as large as P < 0.01. Surface electrocardiograms, stress tests, and 24-hour Holter monitoring showed the correct functioning of the system with an average sensing failure from 0.05 to 1%. In conclusion, VDD stimulation is feasible with a single unipolar lead and a floating atrial electrode in conjunction with a pacemaker generator (CPI 910 ULTRA II) originally designed for permanent twin-lead implantation.     

A New Endocardial "Over-the-Wire" or Stylet-Driven Left Ventricular Lead:

Transvenous left ventricular (LV) leads are primarily inserted "over-the-wire" (OTW). However, a stylet-driven (SD) approach may be a helpful alternative. A new polyurethane-coated, unipolar LV lead can be placed either by a stylet or a guide wire, which can be inserted into the lead body from both ends. The multicenter OVID study evaluates the clinical performance of this new steroid- and nonsteroid eluting lead. The primary endpoint is the LV lead implant success rate after identification of the coronary sinus (CS). Secondary endpoints include complication rate, short- and long-term lead characteristics, overall procedure and LV lead placement duration, total fluoroscopy time, and lead handling characteristics ratings. To date, 96 patients with heart failure (68 ± 9 years old, 76% men) are enrolled. The CS was identified in 95 patients and, in 85 (88.5%), the LV lead was successfully implanted. The final lead positioning was lateral in 41%, posterolateral in 35%, anterolateral in 18%, and great cardiac vein in 6% of patients. In 70%, the 85 successful implantations, both stylet-driven and guide-wire techniques were used, a stylet only was used in 22%, and a guide wire only in 8%. Mean overall duration of 85 successful procedures was 112 ± 40 minutes, total fluoroscopy time 28 ± 15 minutes, and the duration of LV lead placement was 35 ± 29 minutes. During a 3-month follow-up, the loss of LV capture occurred in three and phrenic nerve stimulation in six patients. The mean long-term pacing threshold is 0.8 V/0.5 ms and pacing impedance is 550 Ω. The OVID data suggest that these new leads are safe and effective. The choice of both OTW and SD techniques during lead implantation offers greater procedural flexibility.     

Vas Deferens and Seminal Vesicles Epithelium after Castration: a SEM Study

Vas deferens und Samenbläschen-Epithel nach der Kastration: Eine Rasterelektronenmikroskopische Untersuchung
Mittels der Rasterelektronenmikroskopie wurden die Auswirkungen der Orchidektomie auf das Vas deferens und das Samenbläschenepithel von 20 erwachsenen Albinoratten untersucht. Die innere Oberfläche des Vas deferens der kastrierten Ratte zeigte eine Reduktion der Höhe und der Verdickung der Mukosafalten, sowie an der Zellspitze eine beträchtliche Abnahme der Mikrovilli und das Verschwinden der sekretorischen Bläschen.
Bei den Samenbläschen bewirkte die Kastration ebenfalls eine Abflachung der Mukosafalten und eine Reduktion der Mikrovilli an den apikalen Zellstrukturen; ebenfalls verschwanden die Sekretionsgranula. Diese Veränderungen liefern den Beweis einer Abnahme der Absorptionskapazität und einer Suppression der sekretorischen Aktivität dieser Epithelien als eine Folgerung aus dem Abfall der Androgenwerte.     

Cost-effectiveness of immunizations: The Gambia revisited

This paper reports on the results of an intensive study of thecosts and cost-effectiveness of the Expanded Programme on Immunization(EPI) in The Gambia. Costs in 1988, for the nation as a wholeand for a large sample of specific local delivery sites, andtheir relation to vaccination coverage are presented. The total and average costs of the full national EPI fell impressivelyin The Gambia from about US$1.50 per dose in the early 1980sto US$0.60 in 1988. That conclusion is reinforced by improvementsin vaccination coverage and by a very large decline in costper fully immunized child from about US$19.00 to US$5.64. Comparisonsof the latter finding with the earlier Gambian value, and withother developing countries' figures, suggest a highly cost-effectiveEPI for 1988. Some of the major reasons for this were good administration,widespread deployment of delivery teams, and effective socialmobilization (community awareness) efforts. The study offers site-specific cost estimates that reveal largevariations in average costs among centres. Lower average costsappear to be based on economies of scale and greater intensityof use of facilities and teams, together with better management.As with the estimates for the full national programme, thesevariations are not explicable simply as artefacts of methodologicaltechniques and assumptions. Although recent (1988) Gambian data indicate relatively lowcosts and high cost-effectiveness, the continuation of, andprobable increase in, other threats to health than vaccine-preventablediseases pose daunting challenges to all parties concerned withimproving the allocation of scarce resources for the wellbeingof the Gambian people, and of others in the developing world.     

Pentoxifylline improves haemoglobin and interleukin‐6 levels in chronic kidney disease

Aim: To assess whether pentoxifylline improves anaemia of chronic kidney disease (CKD) via suppression of interleukin‐6 (IL‐6) and improved iron mobilization. Background: CKD patients may have elevated IL‐6 and tumour necrosis factor alpha levels. These cytokines can increase hepcidin production, which in turn reduces iron release from macrophages resulting in reduced availability of iron for erythropoiesis. In experimental models, pentoxifylline was shown to reduce IL‐6 expression. Methods: We studied 14 patients with stages 4–5 CKD (glomerular filtration rate <30mL/min per 1.73 m²) due to non‐inflammatory renal diseases. None of the patients had received immunosuppressive or erythropoietin‐stimulating agents or parenteral iron. Patients had weekly blood tests for iron studies and cytokines during a control run‐in period of 3 weeks and during 4 weeks of pentoxifylline treatment. Results: Ten patients (eGFR 23 ± 6 mL/min) completed the study. At the end of the run‐in period average haemoglobin was 111 ± 5 g/L, ferritin 92 ± 26 µg/L, transferrin saturation 15 ± 3% and circulating IL‐6 10.6 ± 3.8 pg/mL. Tumour necrosis factor alpha values were below threshold for detection. Treatment with pentoxifylline reduced circulating IL‐6 (6.6 ± 1.6 pg/mL, P < 0.01), increased transferrin saturation (20 ± 5%, P < 0.003) and decreased serum ferritin (81 ± 25 µg/L, P = NS). Haemoglobin increased after the second week of pentoxifylline, reaching 123 ± 6 g/L by week 4 (P < 0.001). Conclusions: Pentoxifylline reduces circulating IL‐6 and improves haemoglobin in non‐inflammatory moderate to severe CKD. These changes are associated with changes in circulating transferrin saturation and ferritin, suggesting improved iron release. It is hypothesized that pentoxifylline improves iron disposition possibly through modulation of hepcidin.