[Perioperative management for cardiovascular implantable electronic devices]

Cardiovascular implantable electronic devices (CIED) are an important part of modern cardiology and careful perioperative planning of these procedures is necessary. All information relevant to the indication, the procedure, and the education of the patient must be available prior to surgery. This provides the basis for appropriate device selection. Preoperative antibiotic prophylaxis and perioperative anticoagulation management are essential to prevent infection. After surgery, postoperative monitoring, telemetric control, and device-based diagnostics are required before discharge. These processes need to be adapted to the increasing trend towards outpatient care. This review summarises perioperative management based on practical considerations.

Novel protocol for optimal utilization of HPSD approach for pulmonary vein isolation

BACKGROUND

The efficiency of pulmonary vein isolation (PVI) depends on the durability of RF lesions. Recent studies documented sustained continuity of ablation lines, improvements in durability, and expected clinical outcomes through altered settings in duration and power. However, the ablation strategy has not been adapted to this new approach and different biophysics of lesion formation.

PURPOSE

The aim of this study was to demonstrate that by adjusting the ablation approach to the broader geometry of lesions by increasing the minimal spacing between adjacent RF, a further significant reduction of procedural time while maintaining sufficient long-term outcomes is achievable.

METHODS

The presented study was a prospective, observational multi-center trial. The periprocedural data were compared with data from a consecutively collected historical cohort.

RESULTS

In total, 196 patients were included (mean age 62 ± 11 years, male 64.3%). Procedural duration, RF time, and LA dwelling time were significantly shorter in the HPSD group compared with the standard group (73 ± 26 min vs. 98 ± 36 min, p < .001; 14 ± 7 min vs. 33 ± 12 min, p < .001; and 59 ± 21 min vs. 77 ± 32 min, p < .001, respectively). Mean AF-free survival in the first year of follow-up was 304 ± 14 days in the HPSD group versus 340 ± 10 days in the standard group (log-rank p = .403). There were no statistically significant differences in the complication rates between the groups.

CONCLUSION

Increasing the minimal distance between individual application points simplifies AF ablation and further reduces procedure time without negative effects on efficacy and safety. Larger studies are needed to optimally utilize this approach.

A Simplified Stepwise Approach to Echo Guidance during Percutaneous Mitral Valve Repair

Percutaneous transcatheter edge-to-edge reconstruction of the mitral valve is a safe and well-established therapy for severe symptomatic mitral regurgitation in patients with high surgical risk. Echocardiographic guidance in addition to fluoroscopy is the gold standard and should be performed using a standardized technique. This article lays out our reproducible step by step echocardiographic guide including views, measurements as well as highlighting possible difficulties that may arise during the procedure. This article provides detailed and chronological echocardiographic views for each step of the procedure, especially preferences between 2D and 3D imaging. If needed, pulse wave, continuous wave and color doppler measurements are described. Furthermore, as there are no official recommendations for the quantification of mitral regurgitation during the percutaneous edge-to-edge-repair procedure, advice is also included for echocardiographic quantification after grasping the mitral leaflets and after device deployment. In addition, the article deals with important echocardiographic views to prevent and deal with possible complications during the procedure. Echocardiographic guidance during transcatheter mitral valve repair is mandatory. A structured approach improves the collaboration between interventionist and imager and is indispensable for a safe and effective procedure.

[Continuation of ICD treatment at the time of device exchange without adequate treatment?]

INTRODUCTION

Due to improved treatment of heart failure, patients are older and have more comorbidities at the time of an elective device exchange. This leads to higher rates of complications and represents an opportunity for re-evaluation of the implantable cardioverter defibrillator (ICD) treatment.

OBJECTIVE

This article reviews the current literature regarding the indications for continued ICD therapy and device exchange in patients who have never received adequate treatment through the ICD.

MATERIAL AND METHODS

Patients with primarily prophylactic indications, who have not received adequate treatment and have shown significant improvement in the left ventricular ejection fraction (LVEF) >35%, have a significantly lower risk of ventricular arrythmia (VA) after device exchange. Although further ventricular events can occur in these patients, the continuation of ICD treatment should be individually discussed in cases of high age and increased comorbidities. In female patients with a non-ischemic cardiac myopathy and an almost normalized LVEF, mostly during cardiac resynchronization therapy (CRT), a discontinuation of ICD treatment or downgrading to CRT with pacemaker (CRT-P) treatment should be discussed.

CONCLUSION

At the time of an elective device exchange for primarily prophylactic indications, the possibility to discontinue ICD treatment can be discussed with patients who have not experienced adequate treatment. Additional factors, such as LVEF, age, sex and comorbidities of the patient should be taken into consideration in order to make an individualized decision. As prospective randomized studies are lacking, it is not possible to give generally valid recommendations.

Quantitative Erhebungen des Sozialstatus

Es wird ein Befragungssystem beschrieben, welches sich ausschließlich auf objektiv und numerisch faßbare soziologische Gegebenheiten bezieht, die gemeinsam den quantitativen Sozialstatus des Befragten bilden. Dabei dienen die Fragen nicht nur der Information über den Patienten selbst, sondern auch über seine Angehörigen. Die den Probanden selbst betreffenden Fakten werden inhaltlich und in ihrem zeitlichen Verlauf besonders exakt erfragt. Auf diese Weise soll ein quantitatives Datenmaterial aus einem relativ breiten Spektrum soziologischer Gegebenheiten sowie deren zeitlicher Zusammenhänge für eine Auswertung nach den Methoden der multivariaten Statistik gewonnen werden. Von den Ergebnissen einer solchen Auswertung wird eine geeignete Grundlage für sozialmedizinische bzw. medizinsoziologische Schlußfolgerungen erhofft.

Ultrafast demagnetization in bulk versus thin films: an ab initio study

We report ab initio simulations of the quantum dynamics of electronic charge and spins when subjected to intense laser pulses. By performing these purely electron-dynamics calculations for a thin film and for the bulk of Ni, we conclude that formation of surfaces has a dramatic influence of amplifying the laser induced demagnetization. The reason for this amplification is enhanced spin-currents on the surface of the thin films. We show that the underlying physics of demagnetization for bulk is dominated by spin-flips induced by spin-orbit coupling. In the case of thin films, the dominant cause of demagnetization is a combination of the flow of spin-currents and spin-flips. Furthermore, a comparison of our results with experimental data shows that below  ∼120 fs processes of demagnetization are entirely dominated by purely electronic processes followed by which dissipative effects like the Elliott-Yafet mechanism start to contribute significantly.

Evaluation of the efficacy and safety of imidacloprid 10% plus moxidectin 2.5% spot-on in the treatment of generalized demodicosis in dogs: results of a European field study

Efficacy and safety of the test product imidacloprid 10%+moxidectin 2.5% spot on (Advocate, Advantage multi) in the treatment of canine generalized demodicosis were evaluated in a multi-centre, controlled, randomized, blinded field study in Albania, France, and Germany. The study was conducted according to a non-inferiority design to demonstrate that the efficacy of the test product is not inferior to that of a control product containing milbemycin oxime (Interceptor, tablets for oral application). Of the 72 dogs enrolled, all of which expressed clinical signs of generalized demodicosis, 63 completed the study. Of these, 30 dogs were treated 2-4 times, at 4-week intervals, with the test product at the recommended dose of at least 0.1 ml/kg body weight. Thirty-three dogs were treated daily for two to four periods of 4 weeks with the control product according to label instructions (0.5-1 or 1-2 mg/kg body weight). Presence of mites in deep skin scrapings and clinical improvement were assessed 3-6 times at each inspection at 4-week intervals. Treatment was discontinued in dogs negative for mites on two subsequent examinations 4 weeks apart or at the last examination on day 84. At the end of the trial, dogs in both groups showed a similar clinical improvement. No Demodex mites were detected in 26 of 30 dogs treated with imidacloprid/moxidectin and in 29 of 33 dogs treated with milbemycin oxime. Statistical evaluation confirmed that the efficacy of the test product in the treatment of generalized canine demodicosis was not inferior to that of milbemycin oxime.

Effects of a combinations of emodepside and praziquantel on parasites of reptiles and rodents

A new combination of two anthelmintic compounds containing emodepside and praziquantel (Profender, Bayer AG, Levekusen, Germany) was tested in pet rodents and reptiles. Topical application of the two compounds led to the quick disappearance of nematodes and cestodes from a broad spectrum of hosts including mice, jirds, snakes, anole lizards, turtles, monitor lizards, etc. In reptiles the dosage had to be increased, since the thick outer layer of the epidermis hinders the penetration of the compounds. In animals with an extremely thick epidermis (e.g. monitor lizards, leguans) the new product was applied under the armpits.

Efficacy of toltrazuril as a metaphylactic and therapeutic treatment of coccidiosis in first-year grazing calves

A multicentric, placebo–controlled, randomised, blinded and blocked field study was conducted to evaluate the efficacy and safety of toltrazuril (Baycox^®, Bayer AG, Leverkusen, Germany) in the treatment of coccidiosis in first–year grazing calves naturally infected with Eimeria spp. Three–hundred and thirty–one calves were enrolled in the study and allocated to one of two treatments at a ratio of 1:1. One hundred and sixty–seven animals were treated once orally with 15 mg/kg toltrazuril, and 164 animals served as placebo–treated controls. Two treatment regimes were compared, a metaphylactic (treatment on the day, or 1 day after, turn out) and a therapeutic treatment (4 or 7 days after turn out). During an observation period of 14 days after treatment the animals were clinically examined for diarrhoea and faecal samples were regularly assessed for Eimeria oocysts. Other possible causes of diarrhoea were excluded on the basis of microbiological and virological examination. Animals were predominantly infected with Eimeria alabamensis. Number of days with diarrhoea in animals treated with toltrazuril was significantly lower compared to the placebo–treated group (therapeutic treatment: P=0.0024; metaphylactic treatment: P<0.0001). Furthermore, the number of animals with diarrhoea during the observation period for a minimum of at least 3 days, the number of animals positive for Eimeria oocysts, and the number of animals with both diarrhoea for a period of at least 3 days and positive for Eimeria oocysts, were signiflicantly lower (P<0.01), in the toltrazuril– compared to the placebo–treated animals. Body weight in the toltrazuril–treated animals significantly exceeded that of the placebo–treated animals at the end of the observation period. Mean difference in body weight was higher in the metaphylactic (+7.3 kg) compared to the therapeutic treatment group (+3.4 kg). No adverse reactions were observed. The results indicate that toltrazuril is highly efficacious and safe in the metaphylactic and therapeutic treatment of coccidiosis caused by E. alabamensis in first–year grazing calves.

A phase II trial of first-line bevacizumab in combination with pemetrexed and carboplatin in advanced nonsquamous non-small cell lung cancer (NSCLC)

e19091

Background: Combining bevacizumab (Bev) with platinum doublet yields a survival benefit in previously untreated patients with advanced nonsquamous non-small cell lung cancer. Carboplatin with pemetrexed is an efficient combination that is potentially less toxic. This phase II trial evaluates the efficacy and the safety of adding bevacizumab to carboplatin and pemetrexed in advanced non-small cell lung cancer. Methods: This is a single arm, open-label phase II trial. Eligibility stipulated enrollment of patients with stage IIIB/IV non-squamous non-small cell lung cancer with an ECOG PS 0–1 and no other contraindications to Bev. Treatment consisted of pemetrexed 500 mg/m2, carbo AUC 6 and Bev 15mg/kg on day 1, repeated every 3 weeks. If clinical benefit was proven, patients received Bev maintenance until progression. The response was evaluated every two cycles. The primary endpoint was time to progression (TTP); secondary endpoints included overall survival, response rate (RR) and grade 3–4 toxicities. Results: As of September 2008, 27 out of 42 projected patients were enrolled of which, 14 were males and 13 females; median age 68 (72% older than 60); IIIB/IV 5/22; median number of cycles 9 (range 2–33). At the time of analysis, 25 patients were evaluable. Preliminary results show a median time to progression of 7.25 months (95% CI, 6.4 to 8.2). 23 patients (92%) had disease control (95%, CI 82–96%) with an overall response rate of 36% (95%, CI 25–47%).14 patients had stable disease (56%), 8 had partial response (32%) and one achieved a complete response (4 %). Median survival has not yet been reached. Grade 3/4 adverse events include: Cerebral ischemic event (N=1), Anorexia (Gr 3: N= 5/ Gr 4: N= 4), gastrointestinal fistula (N=1), hypertension (Gr3: N=3), epistaxis (Gr 3 N=1), vomiting (Gr 3; N= 3), fever (Gr 4: N=1) and neuropathy (Gr 3: N=2). Conclusion: The addition of bevacizumab to carboplatin and pemetrexed appears to be an active first line treatment with a high disease control rate and an acceptable toxicity profile in the setting of advanced non-small cell lung cancer.

No significant financial relationships to disclose.

Phase II trial of bevacizumab plus pemetrexed and carboplatin in previously untreated advanced nonsquamous non-small cell lung cancer

18163

Background: A randomized phase III trial has demonstrated the efficacy and safety of high dose bevacizumab (15 mg/kg) with carboplatin and paclitaxel in previously untreated advanced nonsquamous NSCLC (Sandler et al, NEJM 2006). Pemetrexed has also shown significant activity in advanced NSCLC. Clinical investigation of combination bevacizumab (BEV), pemetrexed (PEM) and carboplatin (CARBO) is therefore of interest in this population. Methods: Phase II, open label study in stage IIIB/IV NSCLC: eligible patients have non- squamous histology and no prior chemotherapy, brain metastasis, gross hemoptysis, tumor proximity to major vessels, uncontrolled hypertension or anticoagulation. All patients receive PEM (500 mg/m2), CARBO (AUC 6) and BEV (15 mg/kg) every 21 days. Patients are pretreated with vitamin B12 1,000 mcg every 9 weeks and folic acid 1 mg daily. Responses are assessed every 2 cycles. Patients with CR, PR or SD receive maximum of 6 cycles followed by BEV (15 mg/kg) maintenance. Our primary objective is to determine time to progression and secondary objectives include response rate, overall survival, and safety of the combination. Results: 14 patients (9 female/ 5 male; median age 62 years; range 34–77; 2 stage IIIB/12 stage IV, all ECOG PS 0 or 1) have been entered. Median number of cycles received is 5.5 (range 2 - 15). 12 patients are evaluable for response. 9 patients continued to have disease control at a median duration of 20.2 weeks (range 5–52) with 6 PRs and 3 SDs (response rate 60%; disease control rate 75%). 5 patients proceeded to BEV maintenance with 2 still ongoing. Overall survival data is immature to date. Toxicity data is available for all patients. Grade 3/4 toxicities have included neutropenia (4), nausea/vomiting (2), BEV related allergic reaction (1) and epistaxis (1). Conclusions: Combination BEV, PEM and CARBO is safe, well tolerated and shows promising activity to date. The regimen is not associated with alopecia, neuropathy or arthralgias/myalgias, and is conveniently administered. Enrollment continues and updated results will be presented.

No significant financial relationships to disclose.

Phase I trial of combination therapy with 90Y ibritumomab tiuxetan and gemcitabine in patients with non-Hodgkin’s lymphoma

17514

Background: Zevalin (Z) is an effective therapy in patients with relapsed or refractory low grade, follicular, or transformed B-cell non-Hodgkin’s lymphoma (NHL). Gemcitabine (gem) also is active against NHL and is a potent radiation sensitizer. We are conducting a phase I trial to assess the safety of concomitant administration of Z and gem in patients with NHL. Methods: The starting gem dose is 250 mg/m2 on days 1 and 8. Nine patients in three cohorts will be treated with 250 mg/m2 of gem with 0.2, 0.3 or 0.4 mCi/kg of Z. The next cohort can accrue after all patients in the prior cohort have hematologic toxicity has recovered to grade 2 or after 60 days from the date of the last treated patient in the previous cohort. Once it is confirmed that a Z dose of 0.4 mg/kg can be safely administered with gem 250 mg/m2, gem will be escalated according to a Bayesian based system. Response evaluation is based on the International Workshop on Standardized Response Criteria for Non-Hodgkin’s lymphomas. Eligibility criteria include: any histology of recurrent NHL (not candidates for high dose therapy), platelets ≥ 150,000/ul; < 25% bone marrow involvement by lymphoma; prior radiation to < 25% radiation of bone marrow and no prior bone marrow or stem cell transplant. Results: Five patients have been treated thus far, two with follicular NHL (FL) and three with diffuse large B cell (DLBCL). Median age is 75 (range 55–82). The median number of prior treatments is 2 (range 1–6). One patient with DLBCL is not evaluable. The first three patients received 0.2 mCi/kg and next two patients 0.3 mCi/kg of Zevalin. Toxicity consists of grades 2 & 3 myelosuppression in the first 3 weeks in 3 pts. due to gem and then of grade 2 in 1 pt. at 6 to 8 weeks as is usually seen with Z. One grade 3 leukopenia and one grade 2 thrombocytopenia have been observed resolving within one week. One grade 3 infection occurred, unrelated to the protocol or the study drugs. No grade 3 or 4 non-hematologic toxicity has been seen. In follow up, two patients with FL and one with DLBCL achieved CRu. One patient with DLBCL has progressed and one is not yet evaluable. Conclusions: Our preliminary findings suggest that Z can be safely combined with gem 250 mg/m2 in the treatment of patients with NHL. Dose escalation to full dose Zevalin and then of gemcitabine is continuing.

[Table: see text]

Clinical and epidemiological characteristics of Eimeria infections in first-year grazing cattle

Infections with Eimeria parasites can lead to severe diarrhoea with considerable clinical and economic consequences in first-year grazing stock. To identify and characterise the cause of diarrhoea observed during previous years, 164 animals on 14 dairy farms in northwestern Germany were included in this study. The calves were physically and parasitologically examined prior to turnout and until 21 days post turnout (d.p.t.). Mean animal weights decreased from 194.9 kg at the start to 189.3 kg bodyweight at the end of the study. In all herds, oocyst counts were very low prior to turnout and increased after the calves had been kept on pasture for at least 7 days. On Day 9 post turnout, 90% and at the end of the study (21 d.p.t.) 70% of all animals showed Eimeria-positive faecal samples. During the course of the study, 79 (48.2%) animals passed faecal samples with more than 100,000 oocysts per gram. The predominant species identified was Eimeria alabamensis, which accounted for more than 83% of the oocysts counted. These parasitological findings matched the clinical observations. Diarrhoea was found in 130 (79.3%) of the study animals. At 5 d.p.t. and thus prior to the rise of faecal oocyst counts, a significant increase in diarrhoea was recorded. Calves showing diarrhoea excreted statistically significantly more often over 100,000 E. alabamensis oocysts per gram faeces (0.28; p = 0.0002) than calves without diarrhoea. Diarrhoea was also found during significantly more study days in animals with high oocyst counts (0.39; p = 0.0001). These data indicate that in endemic areas first-year grazing calves must be considered at risk to develop clinical coccidiosis due to E. alabamensis infection during the first 2–3 weeks post turnout.

Efficacy and safety of imidacloprid 10% plus moxidectin 2.5% spot-on in the treatment of sarcoptic mange and otoacariosis in dogs: results af a European field study

Efficacy and safety of treatment with imidacloprid 10%+moxidectin 2.5% spot-on (Advocate, Advantage multi; Bayer AG, Leverkusen, Germany) were tested in dogs naturally infested with Sarcoptes scabiei or Otodectes cynotis in a multi-centre, controlled, randomized, blinded field study conducted in France, Germany, Albania and the UK. The study was performed according to a non-inferiority design to demonstrate that the efficacy of imidacloprid/moxidectin spot-on was not inferior to that of a control product containing selamectin (Stronghold spot-on; Pfizer). All Sarcoptes-infested dogs were topically treated twice (days 0 and 28) with the dosage recommended by the respective manufacturer (27 dogs with imidacloprid/moxidectin, 26 with selamectin). All Otodectes-infested dogs were treated on day 0 (35 dogs with imidacloprid/moxidectin, 34 with selamectin), and only those still positive on day 28 received a second treatment. Parasitological cure rate in Sarcoptes-infested dogs was 100% for both treatments, while parasitological cures rates in the Otodectes-infested dogs at day 28 and day 56 were 68.6 and 85.7% with imidacloprid/moxidectin, and 64.7 and 88.2% with Stronghold. Non-inferiority of Advocate was confirmed statistically. Clinical assessment of skin lesion scores at day 56 showed that with either product >96% of the dogs treated against sarcoptic mange were improved or cured, the difference between the groups being non-significant. On the basis of a final clinical assessment of lesion scores, 80% of the dogs treated with imidacloprid/moxidectin against otoacariosis and 85.3% of those treated with selamectin were rated cured or improved. Only three mild, possibly drug-related adverse reactions were observed among alI treated animals (two in the imidacloprid/moxidectin group, one in the selamectin group). It is concluded that imidacloprid/moxidectin spot-on is an effective and safe treatment for sarcoptic mange and otoacariosis in the dog.

Effect of dietary beta-carotene on the early embryonic development and uterine fluid composition of gilts

The role of beta-carotene in reproduction was investigated in gilts assigned to three dietary supplementations: VA (4000 IU vitamin A); VA + VA (4000 IU + 8300 IU); VA + BC (4000 IU + 100 mg beta-carotene) per kg diet for 14 weeks. Gilts were slaughtered at day 12 of gestation. In the VA + BC group, number of corpora lutea was lowest, but the number of embryos was greatest, resulting in a non-significant decreased prenatal mortality (p<0.07). The proportion of less developed spherical and tubular embryos compared with filamentous was greatest in the VA + BC group (p<0.01). No differences were observed for vitamin A and retinal binding protein (RBP) in the uterine fluid. When animals were grouped according to the development of blastocysts, vitamin A and RBP levels were higher in the VA + BC group with only filamentous embryos (p<0.01). This indicates that the supplementation of beta-carotene to gilts might affect embryonic losses possibly because of slower alterations in the uterine environment, resulting in a higher and less variable number of embryos, despite an apparently more heterogeneous development.

Uptake of clozapine into HL-60 promyelocytic leukaemia cells

The atypical antipsychotic, clozapine, exerts superior efficacy in therapy-resistant schizophrenia, but unfortunately induces agranulocytosis with an incidence of 0.8 - 1 %. In this study, we investigated the cellular uptake of clozapine into human promyelocytic leukaemia HL-60 cells using HPLC with electrochemical detection. On incubation with 1.25 to 40 microM clozapine for 30 min, a saturable, energy- and temperature-dependent uptake process takes place (K m = 18.8 microM, k cat = 1.36 nmol/5 min/mg protein at 37 degrees C). This suggests membrane passage of clozapine by a carrier mechanism. 10 microM Indatraline, an inhibitor of dopamine, noradrenaline and serotonin (5-HT) reuptake, but not the selective 5-HT reuptake inhibitor fluvoxamine, markedly reduced the transport of clozapine by 62 %, whereas addition of 10 mM glucose to the incubation medium increased intracellular clozapine concentrations by 28 %. Since cyclosporine A, vinblastine or verapamil up to a final concentration of 10 microM did not alter the intracellular accumulation of clozapine, an involvement of P-glycoprotein seems to be unlikely. In summary, clozapine uptake into HL-60 cells meets criteria of an active unidirectional transport. Its molecular correlates remain to be established.

Preoperative predictors of late postoperative outcome among patients with nonischemic mitral regurgitation with 'high risk' descriptors and comparison with unoperated patients

Among patients with chronic nonischemic mitral regurgitation (MR), high short-term mortality risk can be identified by left (LV) and/or right ventricular (RV) ejection fraction (EF) criteria (LVEF </=45% and/or RVEF </=30%). Mitral valve replacement or repair (MVR) significantly improves outcome in this subgroup, but predictors of late postoperative survival are not known, and the benefit of MVR has not been defined in patients matched for severity of LV and RV dysfunction. Therefore, prospective assessment of 14 consecutive high risk MR patients was performed before MVR and during 9 years (average) postoperatively to define echocardiographic and radionuclide angiographic predictors of survival; survival also was evaluated in a contemporaneous series of 9 high risk unoperated MR patients, and in subgroups of operated and unoperated patients matched for EF. Of 14 MVR patients, 4 died (3 cardiac: 1 sudden, 2 congestive heart failure). Only preoperative RVEF </=20% significantly predicted postoperative deaths (rest p = 0.032; exercise p = 0.05). Of 9 unoperated patients, 8 died. Mortality risk of unoperated patients remained higher than that of MVR patients when groups were matched for preoperative LVEF (p = 0.0001). Among patients with RVEF >20%, MVR significantly improved survival versus medical treatment (rest: p < 0.0001, exercise: p = 0.0003). In high risk MR patients, MVR improves survival; preoperative RV performance can define subgroups with different long-term postoperative survival.

Specific binding of 3H-spiperone to peripheral blood cells: relevance for the interpretation of binding studies in psychiatric disorders

1. There is an ongoing discussion regarding the elevated binding of 3H-spiperone to lymphocytes of schizophrenic patients. Several authors described an atypical binding pattern with a saturable high-affinity and a nonsaturable binding site both displaceable by (+)-butaclamol. Recent findings are still controversial (Fartacek et al., 1997; Wodarz et al., 1996), possibly due to methodological differences. The authors investigated 3H-spiperone binding to different peripheral blood cells including B- and T-lymphoblastoids. 2. B-lymphocytes (KD = 0.081 nM; Bmax = 0.46 x 10(-15) mol/10(6) cells) and macrophages (KD = 0.1-1 nM, Bmax = 2.44 x 10(-15) mol/10(6) cells) are characterized by a minor but saturable binding of 3H-spiperone in a concentration range between 0.5 and 1 nM. Above 1 nM, only non-saturable binding was measurable. Interestingly, Epstein-Barr virus (EBV) transformed lymphoblastoids (KD = 0.13 nM) have nearly the same affinity for 3H-spiperone as native B-cells, but an increased number of binding sites (Bmax = 1.76 x 10(-15) mol/10(6) cells). 3. Membranes from B-lymphoblastoids displayed a saturable binding in a concentration between 0 and 1.8 nM of 3H-spiperone (KD = 0.5 nM and Bmax = 1.72 x 10(-15) mol/mg protein). Extraction with 1% digitonin resulted in a similar binding characteristic (KD = 0.17 nM and Bmax = 1.97 x 10(-15) mol/mg protein). 4. T-cells, granulocytes and MOLT-3-cells did not show is a saturable binding even not at high concentrations of 3H-spiperone. 5. The pharmacological profile of the high-affinity 3H-spiperone binding site is clearly different from the dopamine D2 and D4, serotonin 5-HT2 histamine H1 and noradrenergic alpha1 and alpha2 receptor, respectively. 6. In summary, the results suggest that spiperone binding studies to enriched lymphocytes of psychiatric patients should be interpreted cautiously. Variable amounts of leucocytes might result in a higher proportion of nonsaturable, butaclamol displaceable spiperone binding with relevance for the calculation of KD and Bmax of the saturable high-affinity site. Interestingly, homogenous B-lymphoblastoid cell lines have the same binding characteristics as native B-lymphocytes and therefore should be recommended for characterization of 3H-spiperone binding sites.

Active [3H]-dopamine uptake displayed by native lymphocyte suspensions is mainly due to contaminating platelets

Kinetic and pharmacologic properties of specific [3H]-dopamine uptake by native human lymphocytes were investigated. Our results suggest that uptake of [3H]-dopamine measured with lymphocytes after separation over Ficoll-Paque or Percoll is mainly caused by platelets which are always part of freshly prepared lymphocyte suspensions. The investigations were extended to well-defined cell lines in order to compare the pharmacological properties of native and immortalized cells regarding the uptake of [3H]-dopamine without any influence of contaminating cells such as platelets. Using the human neuroblastoma cell line IMR32 we demonstrate a GBR-12909 and cocaine-sensitive specific uptake of dopamine, whereas dopamine uptake in platelets is performed by an imipramine-sensitive serotonin transporter. Blood-derived stable cell lines (MOLT-3 and EBV-transformed B-lymphocytes) exhibited no [3H]-dopamine uptake. The view that specific [3H]-dopamine uptake on native human lymphocytes is mainly caused by platelets and not specific for lymphocytes is supported by the finding that homogenous B- and T-lymphoblastoids (MOLT-3 and EBV-transformed B-lymphocytes) exhibited no comparable uptake.