Identification and characterization of a new splicing variant of vascular endothelial growth factor: VEGF183

The purpose of this study was to determine implant survival rates by means of life table analyses for a cohort of patients not part of a prospective efficacy trial and treated by practitioners at varying experience levels. Prognostic variables associated with implant failure were identified by means of proportional hazards models and advanced statistical methods that account for patient effects. Ninety-nine consecutive patients treated from 1987 to 1991 with follow-up to 1994 were included in this retrospective study. A total of 384 dental implants (79.7% Br?nemark, 19.3% IMZ plasma-sprayed, 1% IMZ hydroxyapatite-coated) were placed and subsequently supported 108 prostheses. Survival and proportional hazards modeling were used to generate Kaplan-Meier survival curves and to identify variables associated with implant failure. Survey data analysis was used to adjust for any patient effects for variables identified as significant through the proportional hazards models. Thirty-four implants failed over the follow-up period (median follow-up time 3.6 years), resulting in an overall failure rate of 8.9%. Seventeen of 99 patients experienced an implant failure. When prosthesis type was excluded from the modeling process, survey data analysis identified posterior location and an implant width of less than 4.0 mm as being associated with implant failure (all P < .05).     

Heart pacemaker with lithium batteries. 2 years' clinical experience

102 lithium-powered cardiac pacemakers manufactured by Cardiac Pacemakers Inc. (CPI 301 UD, 101 UA and 501 UD) were implanted in 94 patients. During the observation time (25 months) the following complications were registered: 2 pulse generator failures, 4 failures of the demand-function, anodic muscle-twitching in 2 patients, 2 erosions of the pacemaker-pocket and 1 hematoma of the pocket. 5 pulse generators were exchanged without malfunction of the pacemaker. In 4 patients reinterventions on the electrode had, to be performed. 4 deaths occurred, none of them related to malfunction of the pacemaker. 2 lithium-powered pacemakers were explanted in other hospitals, for reasons not known to us and 1 patient left the German Federal Republic. 83 patients are under control with well working lithium-powered pacemakers.     

The concurrent implantation of a last-generation automatic defibrillator and a 2-chamber pacemaker

BACKGROUND: Potentially lethal interactions between concomitantly implanted pacemaker and automatic first-generation cardioverter-defibrillator have been reported. We therefore evaluated the reliability and safety of simultaneous implantation of dual-chamber pacemakers with a fourth generation cardioverter-defibrillator incorporating an improved arrhythmia detection system. METHODS: Concomitant implantation of an automatic cardioverter defibrillator and a dual-chamber pacemaker was performed in four patients for malignant tachyarrhythmias and symptomatic bradycardia. Two Jewel 7219C and two Micro Jewel 7223 (Medtronic Inc.) implantable cardioverter defibrillators were connected to an endocardial lead (Medtronic Mod. 6936). In 2 patients with a previously implanted cardioverter-defibrillator, the pacemaker was connected to bipolar atrial and ventricular leads. In the 2 patients who already had a dual-chamber pacemaker, the unipolar pacing leads implanted previously were used. At the time of implantation of the second device, interaction testing was performed evaluating ventricular fibrillation detection during high-output asynchronous pacing. Testing for malfunctions, reprogramming or variations of pacing thresholds of the pacemakers after electric shocks was also carried out. Moreover, intracavitary signals, stimulation thresholds and electrical therapies delivered were evaluated during follow-up. RESULTS: During interaction testing, induced ventricular fibrillation was detected, with no delay, in 4/4 cases (100%). After a mean follow-up of 6.3 +/- 5 months (range 2-13), 5 shocks for ventricular fibrillation, 10 shocks for fast ventricular tachycardia and 72 antitachycardia pacings were delivered. All these electrical therapies were considered appropriate. No symptomatic sustained tachyarrhythmia remained undetected. CONCLUSIONS: These data suggest that concomitant implantation of a fourth-generation automatic cardioverter-defibrillator and a dual-chamber pacemaker using either unipolar or bipolar leads can be performed safely. Extreme caution and rigorous interactions testing is nevertheless advised when considering this device combination.     

The metabolism of 22:5(-6) and of docosahexaenoic acid [22:6(-3)] compared in rat hepatocytes

BACKGROUND: Between January 1985 and June 1995, more than 1800 consecutive patients underwent implantation of a new permanent cardiac pacemaker at our institution. Thirty-six patients (0.02%) had 45 reinterventions for infected pacemaker systems. METHODS: in group A, 24 of 27 patients received simultaneous implantation of a new pacemaker. One had reimplantation of the same pacemaker in the same pocket, and two did not require reimplantation. The leads were retained in 19 (70%) of the patients. In group B, nine patients underwent cardiopulmonary bypass or "pursestring" surgery for removal of an infected pacemaker; a new epicardial pacemaker system was simultaneously implanted in seven patients. RESULTS: Identification of an infectious agent failed in 17 patients (47%), and Staphylococci were found in 15 patients (42%). The time from pacemaker implantation to onset of infection ranged from 1 month to 11 years (mean 31 months; median 19 months) and the time from onset of infection to surgical treatment from 1 month to 7 years (mean 7 months; median 2 months). The mean follow-up time is 74 months (range, 1 month to 10 years; median 5 years). There were 9 reoperations in 3 patients (16%) of group A for recurrent infection of their retained leads ultimately necessitating the use of open cardiac surgery. There was no early death; six patients died late due to unrelated causes. CONCLUSIONS: Complete removal of all pacemaker leads is recommended; open heart surgery with the use of cardiopulmonary bypass is indicated in selected cases and is effective and safe.     

A 7-day activity diary for assessment of daily energy expenditure validated by the doubly labelled water method in adolescents

Several authors have reported the single atrioventricular (AV) electrode, comprising an atrial dipole floating in the right atrium, to be a system capable of providing results which are just as satisfactory as those of conventional systems (DDD). Between August 1992 and March 1995, a VDD single electrode pacemaker was implanted in 65 patients (mean age: 73 years +/- 17.2). The indication for implantation was isolated high degree AVB with no apparent sinus dysfunction. Four pacemakers were used: Vitatron (n = 24), Intermedics (n = 23), Medico (n = 13), Biotronik (n = 5). Intraoperative atrial endocavitary recording was 1.8 mV +/- 0.74. 17 patients died from a cause unrelated to pacemaker dysfunction. 4 patients were lost to follow-up. The remaining 44 patients were reviewed in our centre with a mean follow-up of 14.5 months +/- 7 months. Seven pacemakers (16%) were reprogrammed in VVI or VVI (R) mode, because of permanent atrial fibrillation in 3 cases, complete loss of atrial reception in 2 cases and late onset sinus dysfunction in 1 case. In the 41 patients in sinus atrial rhythm, the atrioventricular synchronization rate was greater than 90% in 88% of patients, equal to 76.3% in 2.4% of patients and atrioventricular synchronization was impossible in 9.6% of cases. CONCLUSION: The overall results of our preliminary experience of VDD mode single electrode pacemaker are moderate. The poor results essentially concerned patients with paroxysmal atrial arrhythmias prior to pacing.     

Implantation of atrial pacemaker in patients with sinoatrial failure

From 1990 to 1997 a total of 42 atrial pacemakers (41 of them rate responsive) were implanted in patients with sick sinus syndrome at Aust-Agder Central Hospital, Arendal, Norway. 22 women and 20 men aged 42-86 years (average 69 years) were treated. Follow-up time was from 1-80 months (average 26 months). Sinusbradycardia and sinoatrial block were diagnosed in 17 patients, whereas 25 patients suffered from tachybrady syndrome. It was not necessary to change the pacemaker in any of the patients. One patient developed a second degree atrioventricular, Wenckebach type block, two patients developed permanent atrial fibrillation after seven and 43 months, respectively, and five patients were treated for paroxysmal atrial fibrillation. Thus, 34 patients had no need of antiarrhythmic treatment in the follow-up period. Although over 30% of patients who need a pacemaker in Norway suffer from sick sinus syndrome, only 8-12% of them are treated with atrial pacemakers. Recent studies have demonstrated that in patients with sick sinus syndrome there is greater improvement in prognosis and quality of life with physiological pacing than with ventricular pacing. Therefore, more patients should be considered for implantation of atrial pacemakers.     

Human basophil activation measured by CD63 expression and LTC4 release in IgE-mediated food allergy

BACKGROUNDS AND OBJECTIVES: We present the interim findings of our in-house protocol treating the tumor bed alone after lumpectomy with low-dose-rate (LDR) interstitial brachytherapy in selected patients with early-stage breast cancer treated with breast conserving therapy (BCT). METHODS: From 1 March 1993 through 1 January 1995, 50 women with early-stage breast cancer were entered into a protocol of tumor bed irradiation alone using an interstitial LDR implant. Patients were eligible if their tumor was an infiltrating ductal carcinoma < or =3 cm in diameter, surgical margins were clear by at least 2 mm, the tumor did not contain an extensive intraductal component, the axilla was surgically staged with < or =3 nodes involved with cancer, and a postoperative mammogram was performed. Implants were positioned using a template guide delivering 50 Gy over 96 hr to the lumpectomy bed plus a 1-2-cm margin. Local control, cosmetic outcome, and complications were assessed. RESULTS: Patients ranged in age from 40 to 84 years (median, 65). The median tumor size was 10 mm (range, 1-25). Seventeen of 50 patients (34%) had well-differentiated tumors, 22 (44%) had moderately differentiated tumors, and in 11 (22%) the tumor was poorly differentiated. Forty-five patients (90%) were node-negative while five (10%) had 1-3 positive nodes. A total of 23 (46%) patients were placed on tamoxifen and 3 (6%) received adjuvant systemic chemotherapy. No patient was lost to follow-up. The median follow-up for surviving patients is 47 months (range, 37-59). No patient has experienced a local, regional, or distant failure. Three patients have died at 19, 33, and 39 months after treatment. All were without clinical evidence of recurrent disease and all deaths were unrelated to treatment. Good-to-excellent cosmetic results have been observed in 49 of 50 patients (98%) (median cosmetic follow-up was 44 months with a range of 19-59). No patient has experienced significant sequelae related to their implant. CONCLUSIONS: Interim results with treatment of the tumor bed alone with an LDR interstitial implant appear promising. Long-term follow-up of these patients and additional studies will be necessary to establish the equivalence of this treatment approach compared to standard BCT.     

Final-year-of life pacemaker recipients

BACKGROUND: Older persons who have initial cardiac pacemakers implanted during their final year of life have not been characterized as a group, which makes it difficult to evaluate the suitability of some of their health services utilizations. OBJECTIVE: To help determine how prudently pacemakers are used in this group, we assessed its pacemaker candidates from the perspective of health and ability to perform physical activities of daily living. DESIGN: A retrospective, population-based, cross-sectional study. SETTING: The 1993 National Mortality Followback Survey. PARTICIPANTS: An estimated 1,647,955 persons aged 65 years or older who died in the US in 1993. MEASUREMENTS: Demographic and cause-of-death frequencies obtained by analyzing age, sex, race, and underlying cause-of-death variables in the survey. For persons who had initial pacemakers implanted during their last year of life, we determined the percent of persons, within 10-year age groups, who had no difficulty at any time during their final year of life performing 11 specific physical activities of daily living (e.g., climbing stairs, preparing meals, bathing). These data were obtained from negative responses to questions that asked if the decedents, at any time during their last year of life, had difficulty performing the specific activities. RESULTS: Of the estimated 78,941 persons aged 65 years or older with a pacemaker who died in the US in 1993, 14,158 (18%) had their first pacemaker implanted during their last year of life. Estimated median survival of the final-year-of-life recipients of pacemakers after pacemaker implantation was 5 months. Compared with the general older population that died in 1993, the final-year-of-life recipients of pacemakers group had higher percentages of persons who died of acute disorders (49% vs 19%) and who lived alone in a private home (47% vs 20%), and a lower percentage of persons with Alzheimer's disease (1% vs 7%). The age-stratified means of the percentages of final-year-of-life recipients of pacemakers who had no difficulty performing each physical activity of daily living were all greater than 50. CONCLUSION: Our results suggest that older persons who had initial pacemakers implanted during their final year of life and who died in 1993 were not terminally ill, inactive pacemaker candidates, in general, but relatively independent, physically functional candidates who frequently died abruptly. The physical, mental, and life expectancy factors recommended for consideration by expert guidelines for the implantation of cardiac pacemakers were generally applied to persons in this subgroup.     

Activity of fludarabine in previously treated Waldenstr?m's macroglobulinemia: a report of 71 cases. Groupe Coopératif Macroglobulinémie

PURPOSE: There is no consensus on the treatment of patients with Waldenstr?m's macroglobulinemia (WM) who develop primary or secondary resistance to frontline therapies. We report our experience on the activity and toxicity of fludarabine in 71 patients with WM resistant to prior chemotherapy regimens. PATIENTS AND METHODS: From January 1991 to June 1995, 71 patients were included in this retrospective study. The median age, median time from diagnosis to treatment, median immunoglobulin M (IgM) level, and median number of previous treatments were 68 years (range, 42 to 81), 5.9 years (range, 0.6 to 20), 35 g/L (range, 5 to 126), and two (range, one to four), respectively. RESULTS: Seventy-one patients received a median of six courses of fludarabine. Twenty-one (30%) responded with a partial response and 50 (70%) were considered as treatment failures. Forty-six patients died: 10 in the responder group and 36 in the failure group. Twenty-five patients were alive with a median follow-up time of 34 months. The overall median survival time of all treated patients was 23 months. The time to treatment failure was 32 months. The only factor that favorably influenced the response to fludarabine was a longer interval between the first treatment and the start of fludarabine. Pretreatment factors associated with shorter survival in the entire population were hemoglobin level less than 95 g/L (P = .02) and platelet count less than 75 x 10(9)/L (P = .02). CONCLUSION: The responses rate in this population with a poor prognosis is close to that reported in shorter series. Patients with WM who are resistant to alkylating agents should be identified early, so that salvage therapy with nucleoside analogs can be started without delay.     

Results of atrioventricular synchronous pacing with optimized delay in patients with severe congestive heart failure

To verify that atrioventricular (AV) synchronous pacing (DDD) with short AV delay improves the condition of patients with severe congestive heart failure, we implanted DDD pacemakers in 10 patients with severe heart failure (New York Heart Association [NYHA] class III to IV). One day after pacemaker implantation, the AV delay was optimized by Doppler echocardiographic measurements over the aortic outflow tract. Patients were evaluated regarding NYHA class, stroke volume, cardiac output, ejection fraction, and quality of life at 1, 3, and 6 months after pacemaker implantation. Although the optimized AV delay was associated with short-term improvement in stroke volume and cardiac output (baseline stroke volume = 22 +/- 7 ml, day 1 = 28 +/- 12 ml; p = 0.03: baseline cardiac output = 1.9 +/- 0.6 L/min, day 1 = 2.2 +/- 1.1 L/min; p = 0.10), the mean stroke volume, cardiac output, NYHA class, and ejection fraction did not change significantly after 1, 3, and 6 months of pacing compared with baseline values. Three patients improved in NYHA class during the follow-up. A consistent improvement in stroke volume, cardiac output, NYHA class, and ejection fraction was observed in only 1 patient. In conclusion, we found no beneficial effects of AV-synchronous pacing with optimized AV delay in patients with severe heart failure.     

Carcinoma of the parotid gland. Analysis of treatment results and patterns of failure after combined surgery and radiation therapy

BACKGROUND: The authors retrospectively studied 62 patients with malignant parotid tumors, treated by combined surgery and radiation therapy between 1975 and 1989. No patients were lost to follow-up, and all living patients were interviewed. The median follow-up time was 66 months. RESULTS: Among the 62 patients, there were five isolated local failures. Distant failure was observed in 11 patients. Neck failure was uncommon except in patients with advanced neck disease on presentation. The actuarial 5-year and 10-year local control rates were 95% and 84%, respectively. The corresponding actuarial disease-free survival (DFS) rates were 77% and 65%, respectively. Patients with larger tumors, recurrent disease, or involvement of the facial nerve tended to have lower DFS rates. No statistically significant differences were observed for patients treated with once-daily versus twice-daily radiation therapy fractionation schemes. CONCLUSIONS: Treatment was well tolerated, and severe treatment sequelae were uncommon. In summary, surgery in combination with radiation therapy is highly efficacious in controlling malignant tumors of the parotid gland.     

Image of pseudocapture caused by micro-dislodgment of the electrode in a VDD pacemaker

The new AV sequential pacemakers have improved the suitability for the election of the best pacing mode for each patient. The complexity of the systems may mask some dysfunctions. In the presented case, a failure to capture due to micro-dislodgment, may have been missed in a simple pacemaker control, because of the combination of several factors: the presence of normal AV conduction at that moment, the concordance between the pacemaker stimulus and the conducted QRS complex and the similar morphology of the conducted and paced QRS complex.     

An integrated dual sensor system automatically optimized by target rate histogram

The use of combined sensors and advanced algorithms using different principles can improve rate performance over a single sensor system. Combinations of sensors and more sophisticated algorithms, however, invariably increase the complexity of pacemaker programming. An automatically optimized combined minute ventilation and activity DDDR pacemaker was developed to minimize repeated sensor adjustment. The device used subthreshold (below cardiac stimulation threshold) lead impedance to detect lead configuration at implantation automatically, followed by "implant management," including setting of lead polarity and initiation of DDDR pacing. Automatic sensor adaptation was achieved by programming a "target rate histogram" based on the patient's activity level and frequency of exertion, and the rate profile optimization process matched the recorded integrated sensor response to the target rate histogram profile. In nine patients implanted with the DX2 pacemakers, the implant management gave 100% accuracy in the detection of lead polarity. Rate profile optimization automatically increased the pacing rate during exercise between discharge and 3-month follow-up (hall walk: 78 +/- 3 vs 98 +/- 3 beats/min, and maximal treadmill exercise: 89 +/- 6 vs 115 +/- 5 beats/min, P < 0.001) with a significant increase in exercise duration during maximal exercise (7.18 +/- 1 min vs 9.56 +/- 2 min, P = 0.05). The accuracy of rate profile optimization versus manual programming was assessed at 1 month, and there was no significant difference between pacing rate kinetics and maximal pacing rate between the two methods of programming. In conclusion, pacemaker automaticity can be initiated at implantation and the self-optimized rate adaptive response appeared to be comparable to that derived from a manual programming procedure, which may reduce the need to perform time consuming sensor programming.     

Malignant peripheral nerve sheath tumors. A clinicopathologic study of 28 cases

BACKGROUND: In order to improve management, the files and tissue sections of 28 cases of malignant peripheral nerve sheath tumors (MPNST) diagnosed at the University of Virginia Health Sciences Center between 1960 and 1990 were reviewed. METHODS: Clinical data tabulated included age, sex, race, the presence or absence of von Recklinghausen neurofibromatosis type 1 (NF-1), tumor size, tumor location, type of treatment, and status of surgical margins. Pathologic study included assessment of mitotic rate, divergent differentiation, cellular atypia, necrosis, and vascular reaction. RESULTS: The median disease-free survival time was 11 months, and the median overall survival time was 44 months. Overall survival and disease-free survival were significantly influenced by patient age, tumor location, tumor size, extent of surgery, and quality of margins. Patients with a family history of neurofibromatosis also had better disease-free survival. None of the other clinical variables correlated with survival. CONCLUSIONS: The authors recommended that patients with NF-1 be followed closely for MPNST development. For most cases, treatment should include aggressive surgery with wide surgical margins combined with adjuvant radiation therapy. Chemotherapy may have a role for treatment failures.     

Long-term results of preoperative radiation therapy alone for stage T3 and T4 rectal cancer

BACKGROUND: There has been a resurgence of interest in the use of preoperative radiation therapy, with or without chemotherapy, for locally advanced rectal cancer. The purpose of this study was to analyse the time course and pattern of failure for 74 patients with clinical stage T3 or T4 (cT3-4) rectal cancer treated with preoperative radiation therapy for whom long-term follow-up was available. METHODS: Seventy-four patients with cT3-4 rectal cancer received a median of 45.0 Gy radiation alone followed by surgery 4-8 weeks later. Median follow-up was 90 months; two-thirds of patients were followed for at least 60 months. RESULTS: Following radiation therapy the pathological stage was 4 per cent pT0, 26 per cent pT1-2 and 70 per cent pT3-4. Thirty-two per cent had involved lymph nodes. The actuarial 5-year rates of local control, freedom from distant metastasis and disease-specific survival were 80, 64 and 73 per cent respectively. The corresponding 10-year rates were 73, 51 and 50 per cent. Median times to detection of local and distant recurrence were 34 and 24 months respectively. Eighty per cent of local recurrences were detected within 54 months; 80 per cent of distant recurrences were detected within 57 months. CONCLUSION: In this analysis, the time to detection of both local and distant recurrences following preoperative radiation therapy for advanced rectal cancer was surprisingly long. Almost 5 years (57 months) of follow-up were required to detect 80 per cent of all failures. The 5-year local control rate of 80 per cent compares favourably with that achieved by more aggressive chemoradiation regimens for fixed cancers; however, the high distant failure rate with radiation therapy alone suggests that adjuvant systemic therapy should be investigated.     

Selective shunts in the 1990s

Venous thrombosis is a well-known complication of permanent cardiac pacemaker implantation, particularly, chronic occlusion of the subclavian vein is reported to occur in 20-33% of the cases where the percutaneous approach is performed. We examined 135 asymptomatic patients with digital venography to asses the frequency of venous thromboses causing stenosis and occlusion of the subclavian or anonymous arteries in pacemaker carriers. We considered both one- (44) and two-chamber (91) pacemakers and investigated a possible statistically significant difference between them: we found 21 venous thromboses (15%), seven of them in one-chamber pacemakers (15.9%) and 14 two-chambers pacemakers (15.3%). None of our 94 male and 41 female patients was on anticoagulants or had any evidence of coagulation disorders. Venography was performed 39.3 months (mean) after pacemaker implantation (range: 3-120 months). We conclude that digital venography is a simple and relatively noninvasive method permitting better depiction of subclavian, anonymous and caval veins than Doppler US and also showing some vascular abnormalities which may complicate pacemaker implantation.     

An analytic method for randomized trials with informative censoring: Part 1

Consider a randomized trial in which time to the occurrence of a particular disease, say pneumocystis pneumonia in an AIDS trial or breast cancer in a mammographic screening trial, is the failure time of primary interest. Suppose that time to disease is subject to informative censoring by the minimum of time to death, loss to and end of follow-up. In such a trial, the censoring time is observed for all study subjects, including failures. In the presence of informative censoring, it is not possible to consistently estimate the effect of treatment on time to disease without imposing additional non-identifiable assumptions. The goals of this paper are to specify two non-identifiable assumptions that allow one to test for and estimate an effect of treatment on time to disease in the presence of informative censoring. In a companion paper (Robins, 1995), we provide consistent and reasonably efficient semiparametric estimators for the treatment effect under these assumptions. In this paper we largely restrict attention to testing. We propose tests that, like standard weighted-log-rank tests, are asymptotically distribution-free alpha-level tests under the null hypothesis of no causal effect of treatment on time to disease whenever the censoring and failure distributions are conditionally independent given treatment arm. However, our tests remain asymptotically distribution-free alpha-level tests in the presence of informative censoring provided either of our assumptions are true. In contrast, a weighted log-rank test will be an alpha-level test in the presence of informative censoring only if (1) one of our two non-identifiable assumptions hold, and (2) the distribution of time to censoring is the same in the two treatment arms. We also extend our methods to studies of the effect of a treatment on the evolution over time of the mean of a repeated measures outcome, such as CD-4 count.     

Ten-year disease free survival after transperineal sonography-guided iodine-125 brachytherapy with or without 45-gray external beam irradiation in the treatment of patients with clinically localized, low to high Gleason grade prostate carcinoma

BACKGROUND: The authors report observed 10-year brachytherapy results in the treatment of 152 consecutive patients with clinically organ-confined prostate carcinoma. METHODS: One hundred and fifty-two consecutive patients with T1-T3, low to high Gleason grade, prostate carcinoma were treated between January 1987 and June 1988 at Northwest Hospital in Seattle, Washington. Their median age was 70 years (range, 53-92 years). Of these 152 patients, 98 (64%) received an iodine-125 implant alone (Group 1), and the remaining 54 patients (36%), who were judged to have a higher risk of extraprostatic extension, also were treated with 45 gray (Gy) of external beam irradiation to the pelvis (Group 2). No patient underwent lymph node sampling, and none received androgen ablation therapy. Multivariate regression and the Mann-Whitney rank sum test were used for statistical analysis. Preoperative patient data with associated success or failure outcomes at 10 years after treatment were used for training and validating a back-propagation neural network prediction program. RESULTS: The average preoperative prostate specific antigen (PSA) value, clinical stage, and Gleason grade were 11.0 ng/mL, T2, and 5, respectively. The median posttreatment follow-up was 119 months (range, 3-134 months). Overall survival 10 years after treatment was 65%. At last follow-up only 3 of the 152 patients (2%) had died of prostate carcinoma. Ninety-seven patients (64%) remained clinically and biochemically free of disease at 10 years of follow-up and had an average PSA value of 0.18 ng/mL (range, 0.01-0.5 ng/mL). In these patients a period of 42 months was required to reach the average PSA (0.5 ng/mL). The median to last PSA follow-up was 95 months (range, 3-134 months). Postoperative needle biopsies were negative in 56% of patients, positive in 15% of patients, and not available in 29% of patients. Only 6% of patients developed bone metastasis. At 10 years there was no statistically significant difference in treatment outcome between patients who received iodine-125 alone, and those who received iodine-125 with 45-Gy external beam irradiation (P = 0.08). Nevertheless, in these two groups preoperative PSA, stage, and Gleason grade were significantly different (P < 0.01). In the artificial neural network analysis, pretreatment serum PSA was the most accurate predictor of disease-free survival. CONCLUSIONS: Percutaneous prostate brachytherapy is a valid and efficient option for treating patients with clinically organ-confined, low to high Gleason grade, prostate carcinoma. Observed 10-year follow-up documents serum PSA levels superior to those reported in several published external beam irradiation series, and comparable to those published in a number of published radical prostatectomy series.     

Functional correlation of molecular electronic properties with potency of synthetic carbinolamine antimalarial agents

Dual chamber rate responsive pacing incorporating a mode switching option is increasingly used in patients with chronic paroxysmal atrial fibrillation and high degree AV block. Single-lead VDDR pacemakers have rarely used for this indication. The purpose of this study was to determine their reliability of atrial sensing during atrial fibrillation, the percentage of atrial synchronous ventricular pacing, and the behavior of the sinus rate outside the phases of atrial fibrillation. We studied ten patients with a single-lead VDDR pacemaker implanted for this indication. Follow-up visits were performed at predischarge and after 1, 3, 6, 12, 18, and 24 months. During the mean follow-up period of 18.9 +/- 6.9 months, the atrial sensing thresholds in sinus rhythm remained stable. Atrial synchronous ventricular stimulation was achieved in 68.7 +/- 31.2% (median 82.5%) of the whole follow-up time. All patients showed an adequate atrial rate response during sinus rhythm. Atrial fibrillation was detected by the pacemakers in 24.0 +/- 29.8% of time. In 3 of 10 patients the duration of atrial fibrillation showed a steady increase from visit to visit. The sensed amplitudes of atrial fibrillation ranged from 0.1-1.0 mV. A programmed atrial sensitivity of 0.1 mV was necessary to achieve complete sensing of atrial fibrillation. None of the patients experienced tachycardias with optimized pacemaker programming. Single-lead VDDR pacing incorporating a mode-switching option is useful in patients with high degree AV block and paroxysmal atrial fibrillation, since it provides atrial synchronous ventricular pacing in more than two-thirds of follow-up time. In a subgroup of patients, a progressive increase of the time during atrial fibrillation was demonstrated. A reliable detection of paroxysmal atrial fibrillation requires the programming of the atrial sensitivity to its most sensitive value.     

Effects of magnetic resonance imaging on cardiac pacemakers and electrodes

In phantom studies we investigated the effects of magnetic resonance imaging (MRI) on pacemakers and electrodes. Twenty-five electrodes were exposed to MRI in a 1.5T scanner with continuous registration of the temperature at the electrode tip. Eleven pacemakers (five single chamber and six dual chamber) were exposed to MRI. Pacemaker output was monitored to detect malfunction in VOO/DOO and VVI/DDD modes. A temperature increase at the electrode tip of up to 63.1 degrees C was observed during 90 seconds of scanning. In seven electrodes the temperature increase exceeded 15 degrees C. Although no pacemaker malfunctions were observed in asynchronous pacing mode (VOO/DOO), inhibition and rapid pacing were observed during spin-echo imaging if the pacemakers were set to VVI or DDD mode. Pacemaker function was not impaired during scanning with gradient-echo sequences. Next to pacemaker dysfunction, electrode heating has to be considered a possible adverse effect when exposing patients with pacemakers to MRI.