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Biomedical subjects

R Riccardi

Publications and source records attributed to R Riccardi.

At least 73 records · Page 4Linked to original sources
PubMed1995

[Idiopathic ventricular tachycardia with onset in the verapamil-sensitive left ventricle: the clinical characteristics and long-term follow-up of 37 patients].

BACKGROUND: Idiopathic verapamil-responsive left ventricular tachycardia (IVRLVT) is a rare, well known form of ventricular tachycardia. Issues concerning long-term prognosis, drug prophylaxis and non-pharmacological therapy are rarely reported in the literature. We report the long-term follow-up, the efficacy of various drugs in the prophylaxis and the role of catheter ablation in a large group of patients with IVRLVT. METHODS AND RESULTS: This retrospective study involves 37 patients with a mean age of 28.3 +/- 14.8 years at first IVRLVT episode. The tachycardia morphology was typically with a right bundle-branch block configuration in all cases, with left axis deviation in 33 and right axis deviation in 5 (one patient had the 2 morphologies). Four patients had a mitral valve prolapse; the remaining 33 patients had neither clinical nor echocardiographic signs of heart disease. Only sporadic ventricular extrasystoles were detected at Holter monitoring in 73% of cases; 30% of patients had positive criteria for the presence of late potentials at signal averaged ECG. During electrophysiologic study, the tachycardia could be easily induced in 91% of patients. Mean follow-up is 7.3 +/- 4.7 years; all patients are alive at the end of follow-up. A mean of 2.3 +/- 1.2 drugs was prescribed in 35 patients (94.6%); betablockers were effective in 66% of the cases, verapamil in 20%, class I drugs in 22%, class III drugs in 15%. Both the 2 patients, who never received prophylaxis, and the 4 who stopped medication, utilize verapamil in case of recurrences. Eight patients were submitted to catheter ablation, with DC shock the first 2 patients, with RF energy from the third on; all but one (with DC shock) were successfully cured. CONCLUSIONS: Long-term follow-up confirmed the good prognosis of this form of ventricular tachycardia; a new insight that has been addressed about prophylaxis is the high efficacy of betablockers in preventing relapse and the poor efficacy of verapamil per os in chronic prophylaxis. Radiofrequency catheter ablation is effective and safe, using the earliest ventricular potential and the pace-mapping reproducing the same morphology of the tachycardia in all the 12 leads as a marker to identify the site of RF application, and may be proposed to all patients suffering from frequent episodes of IVRLVT.

Adolescent↗
PubMed1995

The treatment of neuroblastoma with [131I]MIBG at diagnosis.

The potential role [131I]MIBG therapy in untreated, inoperable cases of neuroblastoma (NB) in children was evaluated. Six children, aged 10 months-5 years, were treated at diagnosis. Five (4 stage III and 1 stage IV NB) underwent [131I]MIBG treatment alone (single doses ranging from 2.9 to 6.1 GBq of high specific activity [131I]MIBG. In one case (stage IV NB) [131I]MIBG was preceded by Cisplatin administration (20 mg/m2/day) given over a 5 day period. The results obtained in the first 5 cases were as follows: 1 complete response still lasting after 5 years; 1 partial and 1 minor response allowing further surgery and chemotherapy; 2 stabilization of the disease. The treatment was well tolerated with minimal toxicity. However, apart from the first case all these children relapsed and subsequently died. Therefore [131I]MIBG therapy (9.1 GBq given in 2 courses) combined with Cisplatin as a "radiosensitizer" was used in the sixth case, a patient with widespread bone metastases and massive bone marrow involvement. A very good partial response was obtained in this case. Further surgery (of the primary NB) and multidrug chemotherapy was then possible. In conclusion, [131I]MIBG therapy at diagnosis appears to be effective, low toxic treatment of NB; when integrated with Cisplatin its efficacy seems to improve even more.

3-Iodobenzylguanidine↗
PubMed1995

Treatment with meta-[131I]iodobenzylguanidine and cisplatin in stage IV neuroblastoma.

Metastatic neuroblastoma (NB) continues to have a dismal prognosis. NB is a radiosensitive tumor. Owing to its high concentration in the NB lesions, Metaiodobenzylguanidine (MIBG) has the potential for specifically delivering very large radiation doses to the malignant cells. Encouraging results have been reported with [131I]MIBG used alone in patients resistant to conventional therapy and at diagnosis. We report the first attempts to explore the integration of this new treatment modality with chemotherapy. Among the drugs effective in NB, cisplatin was chosen because of its high degree of activity against NB, its mild hematologic toxicity and the known synergism between cisplatin and radiation. Four patients, 3 with relapsed, heavily pre-treated, progressive stage IV NB, and 1 with stage IV NB at diagnosis, all with a good [131I]MIBG uptake, were investigated with the combined therapy. Two complete remissions and one partial remission were observed in the relapsed patients 4-6 weeks following only one single course of both cisplatin and [131I]MIBG at the "standard" dosage. The only toxicity was hematologic, which was significant and relatively long-lasting, but was not associated with any serious infections or bleeding tendency. The general condition of these patients during the entire study period was excellent. The 4th patient, investigated at diagnosis with a modified less intensive treatment, obtained a partial remission with a mild hematologic toxicity. The provisional conclusion of this preliminary study is that this new form of combined therapy appears very effective in heavily pretreated relapsed patients with progressive disease, and could also be investigated in refractory patients and in patients at diagnosis.

3-Iodobenzylguanidine↗
PubMed1995

In vitro and in vivo studies with no-carrier added radioiodinated MIBG.

An important drawback of radioiodinated MIBG prepared by isotopic exchange (maximum specific activity: 100 Ci/mmol) is that a considerable amount of carrier is present in the "ready to use" radiopharmaceutical, thus affecting MIBG uptake in the target cells. To improve the therapeutic utility of MIBG an interesting method was developed for the no-carrier-added (n.c.a.) radioiodination of MIBG via a halodesilylation reaction using 3-trimethylsilybenzylguanidine (TMSBG) as precursor. In order to investigate its possible clinical usefulness, n.c.a. [125I]- and [131I]MIBG was prepared according this procedure. HPLC analysis of the labeling mixture showed that the labeling yield reached values greater than 98% within 20 minutes at 70 degrees C. HPLC fraction containing [131I]MIBG was then recovered and tetrahydrofurane was removed under nitrogen stream. Biodistribution studies were performed in BALB/c normal mice and compared with those obtained using [131I]MIBG prepared by isotopic exchange. Preliminary results showed that at 4 hours myocardial uptake was significantly higher than that of c.a. MIBG (20.3 +/- 0.4 %ID/g). Adrenal uptake gradually increased over time; at 24 hours adrenal uptake was almost twofold that a 1 hour. MIBG uptake was also studied in the human neuroblastoma cell line SH-SY5Y which has a specific uptake system for MIBG. The kinetic parameters for MIBG in this line are: km = 0.27 +/- 0.03 microM, Vmax = 39.5 + 1.8 pmol/10(6) cell/10 min. Preliminary data from in vitro binding studies showed that significantly higher levels of specifically incorporated radioactivity can be achieved using n.c.a. [125I]MIBG instead of c.a. [125I]MIBG.

3-Iodobenzylguanidine↗
PubMed1994

Clinical pharmacokinetics of carboplatin in children.

The present study was undertaken to evaluate in children the plasma pharmacokinetics of free carboplatin given at different doses and schedules and to evaluate the inter- and intrapatient variability and the possible influence of schedule on drug exposure. A total of 35 children (age range, 1-17 years) with malignant tumors were studied. All patients had normal renal function (creatinine clearance corrected for surface body area, above 70 ml min-1 m-2; range, 71-151 ml min-1 m-2) and none had renal involvement by malignancy. Carboplatin was given at the following doses and schedules: 175, 400, 500, and 600 mg/m2 given as as a 1-h infusion; 1,200 mg/m2 divided into equal doses and infused over 1 h on 2 consecutive days; and 875 and 1,200 mg/m2 given as a 5-day continuous infusion. A total of 57 courses were studied. Carboplatin levels in plasma ultrafiltrate (UF) samples were measured both by high-performance liquid chromatography and by atomic absorption spectrophotometry. Following a 1-h infusion, carboplatin free plasma levels decayed biphasically; the disappearance half-lives, total body clearance, and apparent volume of distribution were similar for different doses. In children with normal renal function as defined by creatinemia and blood urea nitrogen (BUN) and creatinine clearance, we found at each dose studied a limited interpatient variability of the peak plasma concentration (Cmax) and the area under the concentration-time curve (AUC) and a linear correlation between the dose and both Cmax (r = 0.95) and AUC (r = 0.97). The mean value +/- SD for the dose-normalized AUC was 13 +/- 2 min m2 l-1 (n = 57).2+ The administration schedule does not seem to influence drug exposure, since prolonged i.v. infusion or bolus administration of 1,200 mg/m2 achieved a similar AUC (13.78 +/- 2.90 and 15.05 +/- 1.44 mg ml-1 min, respectively). In the nine children studied during subsequent courses a limited interpatient variability was observed and no correlation (r = 0.035) was found between AUC and subsequent courses by a multivariate analysis of dose, AUC, and course number. The pharmacokinetic parameters were similar to those previously reported in adults; however, a weak correlation (r = 0.52, P = 0.03) between carboplatin total body clearance and creatinine clearance varying within the normal range was observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1994

Idiopathic verapamil-responsive left ventricular tachycardia: clinical characteristics and long-term follow-up of 33 patients.

Long-term prognosis, pharmacological prophylaxis and transcatheter ablation in a large group of patients with idiopathic verapamil-responsive left ventricular tachycardia (IVRLVT) are reported in this study. Thirty-three patients with a mean age of 27 +/- 16 years at their first IVRLVT episode, were studied retrospectively. Ventricular tachycardia was of the right bundle branch block morphology in all cases, with left axis deviation in 29 and right axis deviation in five (one patient had the two morphologies). Mitral valve prolapse was present in four patients; no heart disease was found in the remaining 29. Ventricular tachycardia could be electrophysiologically induced in 90% of the patients; Holter monitoring showed only sporadic ventricular extrasystoles in 76%; late potentials were found in 33% of the cases. At the end of a follow-up of 5.7 +/- 4.7 years, no patient had died. Thirty-one patients (94%) received a mean of 2.5 +/- 1.2 drugs; beta-blockers were effective in 71% of the cases, verapamil in 25%, class 1 drugs in 22%, class 3 drugs in 18%. Two patients who never received prophylaxis and four in whom it was stopped, were controlled with verapamil in case of recurrence. Six patients underwent catheter ablation; two with DC shock in whom it was successful in one, and four with radiofrequency energy, with a total success rate. The good prognosis of IVRLVT has been confirmed in a long-term follow-up; a new finding is the high efficacy of beta-blockers for prophylaxis. Radiofrequency transcatheter ablation is an effective and safe therapy for patients with symptoms not controlled by drug treatment.

Adolescent↗
PubMed1994

Nuclear medicine imaging in pediatric oncology.

Nuclear medicine imaging techniques, whether applied in the initial diagnosis or in assessing the response to therapy, are indispensable in the evaluation of malignant diseases that afflict infants and children. The major role of these techniques (bone, 67Ga and 201Tl scintigraphy, imaging with labeled leucocytes, immunoscintigraphy) is that of complementing, in an essential manner, other first choice diagnostic investigations (radiological, bioptic, etc.) such as in evaluating malignant skeletal tumors, soft tissue sarcomas, lymphomas, leukemia and histiocytosis X. Nevertheless, due to their high tissue specificity and/or diagnostic reliability, 99mTc-MDP (or analogues) imaging in the screening of bone metastases, 123/131I-MIBG scintigraphy in the diagnosis and management of neuroblastoma and 131I whole body scan in staging postoperatively differentiated thyroid cancers are proposed as first choice modalities. Well established (131I therapy) or recently developed (131I-MIBG therapy and radioimmunotherapy) therapeutic modalities are available today to be either integrated with or to substitute the conventional treatment of differentiated thyroid carcinoma and neuroblastoma.

3-Iodobenzylguanidine↗
PubMed1993

Uptake and storage of m-iodobenzylguanidine are frequent neuronal functions of human neuroblastoma cell lines.

The mechanisms of the uptake and release of m-iodobenzylguanidine (MIGB) have been studied in 5 neuroblastoma (NB) cell lines and in 4 clonal NB sublines with a homogeneous phenotype. A specific uptake system for MIBG was found in 8 of 9 NB cell lines or subpopulations. The uptake was characterized by temperature dependency, high affinity, saturability, sodium dependency, and imipramine sensitivity. The majority of NB cell lines that possessed a specific uptake system for MIBG were also able to efficiently store the incorporated drug. However, 3 NB cell lines were identified without the ability to retain high levels of MIBG, despite the presence of a specific uptake system. We also report that a clonal subline, SH-EP1, which has a nonneuroblastic phenotype, failed both MIBG uptake and retention. Conversely, the parental cell line, SK-N-SH, and the neuroblastic subline SH-SY5Y possessed both a specific uptake system and the ability to store MIBG. In addition, the induction of neuronal differentiation with retinoic acid increased the velocity of uptake and the storage efficiency for MIBG in the clonal subline SH-SY5Y. We conclude that MIBG uptake and storage should be considered to be frequent but independent neuronal functions of human NB cells.

3-Iodobenzylguanidine↗
PubMed1993

Critical observations on neuroblastoma treatment with 131-I-metaiodobenzylguanidine at diagnosis.

Results of treatment with 131-I-Metaiodobenzylguanidine (131-I-MIBG) in patients with resistant neuroblastoma appear encouraging if one considers that most of the patients had far advanced, intensively pre-treated disease. To further explore the potential role of this new drug in untreated patients, we treated 3 children with stage III neuroblastoma. All three of our cases received 131-I-MIBG at relatively low dose with the complete disappearance of the tumor mass in case 1, whereas in cases 2 and 3 CT scan showed a significant reduction of the tumor mass and, interestingly enough, no evidence of 131-I-MIBG uptake of a tracer dose in the remaining tumor. Particularly, in case 2, the persistence and subsequent progression of part of the tumor mass without 131-I-MIBG uptake after a therapeutic dose of 131-I-MIBG, which apparently destroyed the 131-I-MIBG-positive cell population, clearly suggest heterogeneity at diagnosis, with a dual neuroblastoma cell population, one with 131-I-MIBG uptake and the other without. Besides the biological implications of the 131-I-MIBG uptake heterogeneity in neuroblastoma at diagnosis, our findings suggest that in stage III neuroblastoma patients even a relatively small dose of 131-I-MIBG administered at diagnosis is sufficient to destroy either the primary tumor completely (case 1) or the part of the tumor (case 2 and 3) which shows 131-I-MIBG uptake, without any significant hematologic toxicity. Furthermore, a single course of 131-I-MIBG at the dosage employed does not appear to jeopardize the subsequent use of chemotherapy. In conclusion, if our data are confirmed by further investigation, 131-I-MIBG may be included as a front line drug shortly followed by chemotherapy in future treatment strategies of advanced neuroblastoma without or with minimal bone marrow infiltration.

3-Iodobenzylguanidine↗
PubMed1993

[Ablation of supraventricular paroxysmal nodal reentrant tachycardia].

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most frequent supraventricular tachycardia. The reentry circuit had been said to be localized within the AV node for many years and the first non pharmacological therapy was the surgical or catheter ablation of the AV node. This was, however, too high a price for a generally well tolerated and non life-threatening arrhythmia. Only recently, the endocardial mapping and the results of surgical perinodal dissection showed that part of the reentry circuit was localized in the atrial myocardium near the AV node. The first approach was the ablation of the fast pathway as it is easier to map during AVNRT. However, this pathway is located very close to the AV node, so that its ablation is complicated by a percentage of AV block that is too high (6.2%) considering the good prognosis of this arrhythmia. In order to reduce this risk, the ablation of the slow pathway which is located more posteriorly and more distant from the AV node, was then proposed. Three different approaches have been suggested; one purely anatomic and the other two guided by electrophysiologic markers. If the posterior and middle part of the septum during sinus rhythm is mapped, more posteriorly, near the coronary sinus os, the sharp potential, described by Jackman, is recorded. It is a sharp spike with a high amplitude, associated with an atrial electrogram of very low amplitude. It cannot be modified by atrial pacing and may also be recorded during the uncommon form of AVNRT.(ABSTRACT TRUNCATED AT 250 WORDS)

Catheter Ablation↗
PubMed1993

The success of microsurgical penile revascularization in treating arteriogenic impotence.

The treatment of arteriogenic erectile dysfunction with revascularization techniques has been controversial both in terms of its use and the type of surgical repair. Success rates reported in the literature are based almost exclusively on patient testimonial, without the use of objective post-operative criteria. At our institution from 7/88 through 8/91, 18 patients were treated for arteriogenic impotence using microsurgical penile revascularization. The patient population ranged in age from 23 to 64 years, and each patient underwent a complete history and physical examination, serum hormone testing, psychological evaluation of patient and partner, biothesiometry, penile plethysmography, nocturnal penile tumescence/rigidity testing with a Rigiscan device, and selective pudendal arteriography. One patient was status post a pelvic fracture, 2 lacked identifiable risk factors, 2 had diabetes, 6 were heavy smokers, and 7 had hypertension. Pre-operatively each patient had a suspicious medical history, abnormal plethysmography, abnormal Rigiscan testing, and a hemodynamically significant lesion on angiography. Revascularization was done by anastomosing the inferior epigastric artery to the deep dorsal veing and dorsal artery, or the deep dorsal vein alone if both arteries were atretic. Postoperatively, all 18 patients underwent a personal interview, repeat penile plethysmography, and repeat Rigiscan testing. Six patients reports successful coitus and an additional four were having coitus with the aid of intracavernous pharmacotherapy. Seventy-eight percent (14/18) had improved tracings on penile plethysmography, and 56% (10/18) had normal erectile capability by Rigiscan testing.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Nodal reentry tachycardia: short- and long-term effectiveness and safety of a selective ablation technique of the slow pathway].

BACKGROUND: Various ablation methods have been proposed in the last few years in order to find a radical solution for atrioventricular nodal reentrant tachycardia. The first techniques were surgical, followed by modulation of the fast pathway, causing a prolongation of the P-R interval, the latter involving a 2 to 10% atrioventricular block risk. To reduce this risk, slow pathway ablation was then suggested, with the objective of abolishing atrioventricular reentry. The aim of our study was to evaluate how frequently the recording of peculiar slow potentials was possible in patients with atrioventricular nodal reentrant tachycardia, and to assess short-and long-term efficacy of an ablation technique involving the use of these potentials as electrophysiologic markers. METHODS: One hundred and eighty-eight patients with typical atrioventricular nodal reentrant tachycardia were studied (mean age 47 +/- 18 years). Radiofrequency ablation was guided by peculiar slow potential recordings; when this was not possible, fast pathway ablation, or slow pathway ablation guided only by anatomic markers, were performed. RESULTS: Potentials with peculiar electrophysiologic characteristics were found during sinus rhythm in the median posterior region of the septum, anteriorly to the coronary-sinus ostium, in 92% of patients. These characteristics included: low amplitude; the fact that they occupy the first part of the interval between the atrial and ventricular electrogram; their amplitude diminishes and disappears with increased frequency of atrial stimulation and/or with atrial extrastimulus. Typical atrioventricular nodal reentry tachycardia was no longer inducible in any patient at the end of the procedure with a median of 2 radiofrequencies application per patient. No II or III degree atrioventricular block was caused when ablation was guided by slow potential recordings. During an attempt at fast pathway ablation a complete atrioventricular block was caused in 1 patient. One hundred and eighty-four patients remained asymptomatic during a follow-up of 2 to 24 months; no one showed either a modification of atrioventricular conduction if compared to that found at hospital discharge or proarrhythmic effects. Four patients had one atrioventricular nodal reentrant tachycardia recurrence and a second successful ablation was performed in 2 of these 4 patients. CONCLUSIONS: Peculiar slow potentials, that can be used as electrophysiologic markers for slow pathway ablation, were recorded in the medio-posterior region of the septum in the majority of patients. The fact that this technique, using slow potential as an electrophysiologic marker, was successful in all patients, with very few recurrences and with no serious complications (no II or III degree atrioventricular block) makes it trustworthy and safe.

Action Potentials↗
PubMed1992

Cerebrospinal fluid pharmacokinetics of carboplatin in children with brain tumors.

The pharmacokinetics of carboplatin in cerebrospinal fluid (CSF) and plasma was studied in five children with brain tumors (four medulloblastomas and one ependimoblastoma) who underwent preirradiation treatment with carboplatin. Carboplatin pharmacokinetics was studied following the administration of 600 mg/m2 as a 1-h infusion. Four children were treated a few weeks after surgery, whereas one child with an unresectable tumor was treated prior to surgery. All patients had a ventricular-peritoneal CSF shunt connected to a subcutaneous reservoir. Total platinum and free carboplatin were measured. The mean AUC values for free carboplatin in CSF and plasma were 2.29 +/- 1.20 and 8.18 +/- 1.27 mg ml-1 min, respectively. The mean ratio of CSF AUC to plasma AUC was 0.28 (range, 0.17-0.46). Both plasma peak levels and AUC values showed limited interpatient variability. On the other hand, carboplatin levels in CSF showed substantial interpatient variability, with a greater than 5-fold difference in peak levels and a 3-fold difference in AUC values being recorded. The interpatient difference in CSF pharmacokinetics may have been related at least in part to the different anatomical alterations induced by the surgical procedures or by the presence of a large tumor mass. In the four evaluable patients exhibiting macroscopic residual tumor, we observed one complete remission (CR) and two partial remissions (PR) following two cycles that consisted of two doses of 600 mg/m2 carboplatin given on 2 consecutive days (total dose, 1200 mg/m2) and were separated by a 1-month interval. These results may give some indication as to the optimal dose and schedule for carboplatin administration in the treatment of primitive neuroectodermic tumors (PNET).

Brain Neoplasms↗
PubMed1992

Wolff-Parkinson-White syndrome. Identification and management.

Patients with Wolff-Parkinson-White (WPW) pattern of ventricular pre-excitation may develop paroxysmal re-entrant tachyarrhythmias through the Kent bundle and, less commonly, atrial fibrillation. WPW patients are at risk of sudden death when a rapid ventricular response occurs during atrial fibrillation due to conduction through the accessory pathway. Conduction properties of the accessory pathway and atrial vulnerability, which is the propensity to develop atrial fibrillation, are important parameters for evaluation in these patients. The former can be assessed by means of noninvasive tests, such as stress and pharmacological tests, and with electrophysiological study; the latter only by electrophysiological study. There is no indication for treatment of asymptomatic patients. Antiarrhythmic prophylaxis is required in patients with previous episodes of atrial fibrillation with rapid ventricular response, in patients with paroxysmal re-entrant tachycardias and rapid conduction through the accessory pathway, and in patients with frequent episodes of re-entrant tachycardias of long duration. Vaughan-Williams class IC anti-arrhythmic drugs (propafenone, flecainide) are the first choice for drugs in patients with rapid anterograde conduction through the accessory pathway due to their high efficacy and low incidence of adverse effects, while beta-blockers (atenolol, nadolol) are indicated for patients with re-entrant tachycardias and low conduction capacity through the bypass tract. When pharmacological therapy is ineffective, surgical or catheter ablation of the accessory pathway may be considered.

Arrhythmias, Cardiac↗
PubMed1992

Catheter ablation of accessory pathways in patients with Wolff-Parkinson-White syndrome.

PATIENTS: Fifty-two patients with Wolff-Parkinson-White syndrome underwent transcatheter ablation. All patients were symptomatic. Eighteen had documented episodes of atrial fibrillation, 14 of which also had reentrant tachycardias; the remaining 34 had only episodes of reentrant tachycardias. Forty-nine patients had both anterograde and retrograde conduction through the accessory pathway; 3 had retrograde conduction alone; 2 patients had 2 accessory pathways and 1 had 3. All patients were resistant or intolerant to at least 2 antiarrhythmic drugs. METHODS: All patients were treated with radiofrequency current. Ablation was considered successful if the anterograde and retrograde conduction were completely abolished. Ablation was considered unsuccessful if ablation of only 1 pathway in patients with 2 or more accessory pathways and/or modification of the accessory pathway conduction without interruption was achieved. RESULTS: Accessory pathway ablation was successfully performed in 46 out of 52 patients (88%). Fifty out of 56 accessory pathways were effectively ablated (89%). Thirty-eight required a single session of ablation and 8 additional patients were successfully ablated during a second session. The number of radiofrequency current applications ranged from 2 to 13 (mean 4.1 +/- 2.5). The mean duration of the sessions was 4.30 +/- 1.50 hours (range 2.30 to 9). The mean radiation exposure for session was 55 +/- 25 minutes (range 20 minutes to 2.30 hours). Complications were observed in 2 out of 52 patients. One patient had a transient II degree type 1 atrioventricular block; another patient with severe arterial hypertension had a mild hemorrhagic stroke with complete neurological remission. FOLLOW-UP. Forty-five out of the 46 patients in whom ablation was successful were asymptomatic for arrhythmias during a mean follow-up of 8 months (range 4 to 16), without antiarrhythmic treatment, and without reappearance of preexcitation. One patient showed reappearance of preexcitation at electrocardiogram one month after the ablation, followed by an episode of reentrant tachycardia; this patient underwent a second successful ablation session. CONCLUSIONS: Our results show that ablation techniques have high success rates with no serious complications.

Adolescent↗
PubMed1991

Cranial irradiation and cerebrospinal fluid levels of 6-mercaptopurine in children with acute leukemia.

We measured 6-mercaptopurine levels in the cerebrospinal fluid and plasma of 15 children undergoing treatment for acute leukemia. Plasma and cerebrospinal fluid samples obtained by lumbar puncture were collected before, during, and after cranial irradiation in order to evaluate a possible change in blood-brain barrier permeability to orally administered 6-mercaptopurine. Considerable interpatient variability has been observed in both plasma and cerebrospinal fluid 6-mercaptopurine levels. No statistical differences in the 6-mercaptopurine cerebrospinal fluid levels under the three different conditions could be detected. Our data suggest that cranial irradiation does not significantly influence the cerebrospinal fluid levels.

Administration, Oral↗
PubMed1991

CD36(OKM5)+ dendritic cells in the oral mucosa of HIV- and HIV+ subjects.

In this study, we have investigated by light and electron microscopy the presence, distribution, and inner structure of CD36(OKM5)+ dendritic cells (DC) in the lamina propria and epithelium of the oral mucosa of HIV- and HIV+ subjects; in the latter, both clinically healthy areas and areas of hairy leukoplakia (HL) were studied. Perivascular CD36+ DC were present in the lamina propria of all the specimens studied. They were also found in small numbers in the epithelium of clinically healthy mucosa of HIV- and HIV+ subjects, but were practically absent from the epithelium of HL. CD36+ DC seemed to be regularly HLA-DR+ in HIV-subjects; this positivity was recognized only in some cells in the clinically healthy mucosa of HIV+ subjects, and practically never in HL. Because the only perivascular cells observed in the clinically healthy areas of HIV+ subjects were CD36+, we investigated the ultrastructure of perivascular DC in these same areas. These cells were characterized by the presence of a prominent Golgi apparatus, many lysosomes, and focal adhesions to the extracellular matrix. It may be concluded that 1) CD36+ DC are physiologic components of the oral mucosa, 2) they share some ultrastructural features with macrophages, 3) no differences in numbers were found between HIV+ and HIV- subjects, and 4) these cells are affected in their expression of HLA-DR antigens during HIV infection, particularly in areas of HL. This may be a hint that the antigen-presenting function of these cells in the oral mucosa is negatively affected during HIV infection.

Adult↗