Dosimetric feasibility study ("proof of concept") of refractory ventricular tachycardia radioablation using proton minibeams

PURPOSE

Preclinical data demonstrated that the use of proton minibeam radiotherapy reduces the risk of toxicity in healthy tissue. Ventricular tachycardia radioablation is an area under clinical investigation in proton beam therapy. We sought to simulate a ventricular tachycardia radioablation with proton minibeams and to demonstrate that it was possible to obtain a homogeneous coverage of an arrhythmogenic cardiac zone with this technique.

MATERIAL AND METHODS

An arrhythmogenic target volume was defined on the simulation CT scan of a patient, localized in the lateral wall of the left ventricle. A dose of 25Gy was planned to be delivered by proton minibeam radiotherapy, simulated using a Monte Carlo code (TOPAS v.3.7) with a collimator of 19 0.4 mm-wide slits spaced 3mm apart. The main objective of the study was to obtain a plan ensuring at least 93% of the prescription dose in 93% of the planning target volume without exceeding 110% of the prescribed dose in the planning target volume.

RESULTS

The average dose in the planning treatment volume in proton minibeam radiotherapy was 25.12Gy. The percentage of the planning target volume receiving 93% (V93%), 110% (V110%), and 95% (V95%) of the prescribed dose was 94.25%, 0%, and 92.6% respectively. The lateral penumbra was 6.6mm. The mean value of the peak-to-valley-dose ratio in the planning target volume was 1.06. The mean heart dose was 2.54Gy versus 5.95Gy with stereotactic photon beam irradiation.

CONCLUSION

This proof-of-concept study shows that proton minibeam radiotherapy can achieve a homogeneous coverage of an arrhythmogenic cardiac zone, reducing the dose at the normal tissues. This technique, ensuring could theoretically reduce the risk of late pulmonary and breast fibrosis, as well as cardiac toxicity as seen in previous biological studies in proton minibeam radiotherapy.

Fusion product measurements by nuclear diagnostics in the Joint European Torus deuterium-tritium 2 campaign (invited)

A new deuterium-tritium experimental, DTE2, campaign has been conducted at the Joint European Torus (JET) between August 2021 and late December 2021. Motivated by significant enhancements in the past decade at JET, such as the ITER-like wall and enhanced auxiliary heating power, the campaign achieved a new fusion energy world record and performed a broad range of fundamental experiments to inform ITER physics scenarios and operations. New capabilities in the area of fusion product measurements by nuclear diagnostics were available as a result of a decade long enhancement program. These have been tested for the first time in DTE2 and a concise overview is provided here. Confined alpha particle measurements by gamma-ray spectroscopy were successfully demonstrated, albeit with limitations at neutron rates higher than some 10¹⁷ n/s. High resolution neutron spectroscopy measurements with the magnetic proton recoil instrument were complemented by novel data from a set of synthetic diamond detectors, which enabled studies of the supra-thermal contributions to the neutron emission. In the area of escaping fast ion diagnostics, a lost fast ion detector and a set of Faraday cups made it possible to determine information on the velocity space and poloidal distribution of the lost alpha particles for the first time. This extensive set of data provides unique information for fundamental physics studies and validation of the numerical models, which are key to inform the physics and scenarios of ITER.

Access to innovative medicines for metastatic melanoma worldwide: Melanoma World Society and European Association of Dermato-oncology survey in 34 countries

According to data from recent studies from Europe, a large percentage of patients have restricted access to innovative medicines for metastatic melanoma. Melanoma World Society and European Association of Dermato-oncology conducted a Web-based survey on access to first-line recommended treatments for metastatic melanoma by current guidelines (National Comprehensive Center Network, European Society for Medical Oncology [ESMO] and European Organization for Research and Treatment of Cancer/European Association of Dermato-oncology/European dermatology Forum) among melanoma experts from 27 European countries, USA, China, Australia, Argentina, Brazil, Chile and Mexico from September 1st, 2017 to July 1st, 2018. Data on licencing and reimbursement of medicines and the number of patient treated were correlated with the data on health expenditure per capita (HEPC), Mackenbach score of health policy performance, health technology assessment (HTA), ASCO and ESMO Magnitude of clinical benefit scale (ESMO MCBS) scores of clinical benefit and market price of medicines. Regression analysis for evaluation of correlation between the parameters was carried out using SPSS software. The estimated number of patients without access in surveyed countries was 13768. The recommended BRAFi + MEKi combination and anti-PD1 immunotherapy were fully reimbursed/covered in 19 of 34 (55.8%) and 17 of 34 (50%) countries, and combination anti-CTLA4+anti-PD1 in was fully covered in 6 of 34 (17.6%) countries. Median delay in reimbursement was 991 days, and it was in significant correlation with ESMO MCBS (p = 0.02), median market price (p = 0.001), HEPC and Mackenbach scores (p < 0.01). Price negotiations or managed entry agreements (MEAs) with national authorities were necessary for reimbursement. In conclusion, great discrepancy exists in metastatic melanoma treatment globally. Access to innovative medicines is in correlation with economic parameters as well as with healthcare system performance parameters. Patient-oriented drug development, market access and reimbursement pathways must be urgently found.

An arc control and protection system for the JET lower hybrid antenna based on an imaging system

Arcs are the potentially most dangerous events related to Lower Hybrid (LH) antenna operation. If left uncontrolled they can produce damage and cause plasma disruption by impurity influx. To address this issue an arc real time control and protection imaging system for the Joint European Torus (JET) LH antenna has been implemented. The LH system is one of the additional heating systems at JET. It comprises 24 microwave generators (klystrons, operating at 3.7 GHz) providing up to 5 MW of heating and current drive to the JET plasma. This is done through an antenna composed of an array of waveguides facing the plasma. The protection system presented here is based primarily on an imaging arc detection and real time control system. It has adapted the ITER like wall hotspot protection system using an identical CCD camera and real time image processing unit. A filter has been installed to avoid saturation and spurious system triggers caused by ionization light. The antenna is divided in 24 Regions Of Interest (ROIs) each one corresponding to one klystron. If an arc precursor is detected in a ROI, power is reduced locally with subsequent potential damage and plasma disruption avoided. The power is subsequently reinstated if, during a defined interval of time, arcing is confirmed not to be present by image analysis. This system was successfully commissioned during the restart phase and beginning of the 2013 scientific campaign. Since its installation and commissioning, arcs and related phenomena have been prevented. In this contribution we briefly describe the camera, image processing, and real time control systems. Most importantly, we demonstrate that an LH antenna arc protection system based on CCD camera imaging systems works. Examples of both controlled and uncontrolled LH arc events and their consequences are shown.

Effects of magnetic shear on toroidal rotation in tokamak plasmas with lower hybrid current drive

Application of lower hybrid (LH) current drive in tokamak plasmas can induce both co- and countercurrent directed changes in toroidal rotation, depending on the core q profile. For discharges with q(0) <1, rotation increments in the countercurrent direction are observed. If the LH-driven current is sufficient to suppress sawteeth and increase q(0) above unity, the core toroidal rotation change is in the cocurrent direction. This change in sign of the rotation increment is consistent with a change in sign of the residual stress (the divergence of which constitutes an intrinsic torque that drives the flow) through its dependence on magnetic shear.

Dose-response effect of serum butyrylcholinesterase activity after clinical doses of pancuronium

INTRODUCTION

Low-dose pancuronium is known to affect serum cholinesterase activity (BChE); however, the dose-response effect of clinical doses of pancuronium on BChE has not been investigated.

METHODS

Thirteen ASA I-II patients scheduled for elective surgery requiring muscle relaxation were enrolled in this study. All patients had normal BChE before surgery. Incremental doses of pancuronium (10, 20, 50, and 100 microg/kg) were injected in accordance with surgical needs every 45 min. BChE was measured 3 min after injection by an automatic colorimetric method.

RESULTS

BChE decreased significantly in all except one patient in comparison to the baseline (P < 0.05). However all values remained within normal clinical range. A dose of 100 microg/kg yielded significant decrease in comparison to 10 microg/kg but not to other dosages. Linear regression was not significant for the dose-response relationship (P = 0.05).

CONCLUSION

After clinical incremental doses of pancuronium, BChE remained within clinical range.

Post-tetanic count at adductor pollicis is a better indicator of early diaphragmatic recovery than train-of-four count at corrugator supercilii

BACKGROUND

Because the intensity of neuromuscular block at the diaphragm (DIA) is indirectly assessed, the electromyographic measurements of the DIA (DIA(EMG)) from surface electrodes were related to information provided by visual estimation of neuromuscular transmission at the adductor pollicis (AP) and the corrugator supercilii (CSC) during recovery from vecuronium block.

METHODS

Twelve adult patients were studied during balanced anaesthesia. After induction of anaesthesia and tracheal intubation without neuromuscular blocking agent, supramaximal stimulations were applied to phrenic, ulnar and facial nerves. During recovery from vecuronium 0.1 mg kg(-1) an independent observer blinded to DIA(EMG) counted visually detectable train-of-four (TOF) at CSC (TOF(CSC)) and post-tetanic AP (PTC(AP)) responses. Times to recovery of PTC(AP) = 1, <or=5, <10 and >10, and TOF(CSC) = 1-4 responses were related to DIA(EMG). Values are means (sd).

RESULTS

Reappearance of the first response to PTC(AP) occurred significantly (P < 0.05) earlier and for a lower recovery of DIA(EMG) than that of TOF(CSC) [24 (8) min vs 33 (9) min, and 10 (10)% vs 25 (8)%, respectively]. With PTC(AP) <or= 5 response, DIA(EMG) recovery was 21 (11)%. Recovery of TOF(CSC) = 1 and 2 coincided with DIA(EMG) recovery of 25 (8)% and 47 (9)%, respectively.

CONCLUSIONS

PTC(AP) may better reflect early recovery of vecuronium-induced DIA paralysis than TOF(CSC). The findings suggested that PTC(AP) <or= 5 warranted deep neuromuscular block of the DIA.

TOF count at corrugator supercilii reflects abdominal muscles relaxation better than at adductor pollicis

BACKGROUND

A recovery profile from neuromuscular block similar to that of abdominal (AB) muscles, but different to that of the adductor pollicis (AP) muscle, has been demonstrated at the corrugator supercilii (CSC) muscle. We hypothesized that neuromuscular transmission (NMT) monitoring of CSC might provide useful information on AB relaxation compared with AP. We compared the visual estimation of NMT at CSC and AP with electromyographic measurements of AB during recovery from a vecuronium block.

METHODS

Ten adult patients were studied during balanced anaesthesia. After induction of anaesthesia and tracheal intubation without neuromuscular blocking agents, supramaximal stimulations were applied to three nerves: left 10th intercostal, ulnar, and facial. Electromyographic activity (EMG) of AB was measured (ABemg). After a bolus dose of vecuronium 0.1 mg kg-1, an independent observer blinded to the EMG measurements counted visually detectable train-of-four (TOF) responses at CSC and AP. Values of ABemg associated with 1 to 4 TOF responses at CSC and AP were compared. Values are means (sd).

RESULTS

Reappearance of the first and second TOF responses at CSC occurred significantly (P<0.05) earlier and at lower ABemg recovery than that of AP [35 (8) and 41 (9) min vs 51 (10) and 56 (12) min; and 17 (8) and 26 (9)% vs 56 (10) and 75 (11)%, respectively].

CONCLUSIONS

We demonstrated that the TOF response count at the CSC, compared with the AP, allowed a better quantification of the degree of AB muscle relaxation during recovery from vecuronium block.

[Rare endocrine tumors of the pancreas with secretion of cortisol]

The endocrine part of the pancreas consist 2% from the mass of the gland and it is built from little cells with name Langerhan's islands. The increased secretion of cells provokes to appearance of classic clinical syndrome, which is conditioned by large quantity of hormone in circulation of the blood. The endocrine tumors of the pancreas (ETP) are arisen out of cells that have large quantity to APUD-system.

MATERIAL AND METHOD

We present a case report of rare ETP with secretion of cortisol (MEN2 syndrome), which is of interest by reason of the fact that this case report is the first announce in Bulgaria about similar tumor. Corporocaudal resention of the pancreas with spleenectomy has been made.

RESULTS

Tumor cells with highly expresion (+++) of hromogranin were determined. The histological conclusion was malignant ETP (APUD system tumor)with secretion of cortisol. A decrease of the level of glucose in blood circulation, a decrease of blood pressure and reduction of the body weight were determined with range of first three postoperative weeks.

CONCLUSION

The aims of the surgical therapy are a control over the level of hormones, clear resection and maximal organ saving operation.

Does repetition of post-tetanic count every 3 min during profound relaxation affect accelerographic recovery of atracurium blockade?

BACKGROUND

Post-tetanic count is a valuable method to assess profound neuromuscular blockade. However, subsequent responses to repetitive stimulation might be altered due to post tetanic facilitation (PTF). To avoid PTF, it has been advocated to limit the interval of stimulation from 6 to 10 min. The impact of PTF on 90% recovery of the TOF ratio has not been evaluated. Therefore, we assessed the effect of repetitive PTC stimulation on atracurium blockade with the primary outcome being the time to reach 90% TOF recovery in comparison to classical TOF stimulation.

METHODS

After informed consent 20 patients ASA I-II, scheduled for peripheral surgery under general anaesthesia and requiring tracheal intubation were enrolled into the study. Anaesthesia was induced with fentanyl, propofol, and atracurium, 0.5 mg kg(-1). Neuromuscular characteristics were assessed at the adductor pollicis by a TOF Watch((R)) accelerometer (Organon, Teknika, Holland) on each arm. After onset of maximum neuromuscular blockade, repetitive PTC every 3 min on one arm and repetitive TOF stimulation every 15 s on the opposite arm was performed. The following parameters were recorded: onset of maximum blockade, mean time of PTC stimulation, the maximum number of responses to PTC, time of the first and second TOF responses, and recovery profile until 90% TOF ratio.

RESULTS

Time to reach 90% TOF recovery was similar on both arms (48 +/- 9 min), with a difference of 16 +/- 38 s between the arms (P = 0.64). The first and second responses of the TOF on the PTC-stimulated arm appeared at 29 +/- 8 min and 33 +/- 7 min, respectively. On the other arm the responses appeared at 30 +/- 8 min and 35 +/- 8 min, respectively (P < 0.05).

CONCLUSION

Repetitive PTC stimulation every 3 min hastened the first and second responses of the TOF stimulation but we could not detect a significant difference in the 90% recovery of TOF ratio during atracurium blockade.

Interaction between mivacurium and pancuronium: impact of the order of administration

INTRODUCTION

Potentiation of mivacurium by low-dose pancuronium is mostly due to an inhibition of plasma butyryl cholinesterase (BchE) resulting in a decreased rate of hydrolysis of mivacurium. Nevertheless, an interaction at the receptor site could not be ruled out. By changing the order of the muscle relaxant injections, we may lessen the pharmacokinetic interaction and assess the impact at the acetylcholine receptor level.

METHODS

Twenty patients scheduled for general anesthesia with propofol and fentanyl, and isoflurane were randomized into two groups receiving, mivacurium 100 microg kg-1 followed by pancuronium 15 microg kg-1 (group 1) or pancuronium 15 microg kg-1 followed by mivacurium 100 microg kg-1 (group 2). BchE before and after injection of each relaxant was measured. Neuromuscular block was assessed with a force transducer at the adductor pollicis measuring the elicited twitch to ulnar nerve stimulation.

RESULTS

The neuromuscular block was greater when pancuronium was administered before mivacurium (100% versus 96+/-3%; P<0.05). Times to recovery of the elicited twitch response to 25% and 75% of control value were increased by 100% (P<0.05). After pancuronium, decreases in BchE of 11% and 14% in groups 1 and 2 were observed, respectively.

CONCLUSION

Interaction between mivacurium and low dose pancuronium is significant only when mivacurium is injected after pancuronium.

Plasma rotation induced by directed waves in the ion-cyclotron range of frequencies

Changes of the toroidal plasma rotation induced by directed waves in the ion-cyclotron range of frequencies (ICRF) have been identified experimentally for the first time on the JET tokamak. The momentum carried by the waves is initially absorbed by fast resonating ions, which subsequently transfer it to the bulk plasma. Thus, the results provide evidence for the influence of ICRF heated fast ions on plasma rotation.

Comparison of the neuromuscular blocking effect of cisatracurium and atracurium on the larynx and the adductor pollicis

BACKGROUND

Cisatracurium unlike atracurium is devoid of histamine-induced cardiovascular effects and this alone would be the greatest advantage in replacing atracurium for the facilitation of tracheal intubation. On the other hand, 2 ED(95) doses of cisatracurium (100 micro g/kg) do not yield satisfactory intubating conditions such as those seen with equipotent doses of atracurium and therefore the recommended intubating dose of cisatracurium is 3 ED(95). To understand this discrepancy better, we evaluated the potency and onset of atracurium and cisatracurium directly at the larynx adductors in humans.

METHODS

The study was conducted in 54 patients (ASA class I or II) undergoing peripheral surgery requiring general anesthesia. Cisatracurium 25-150 micro g/kg or atracurium 120-500 micro g/kg intravenous (i.v.) boluses doses were administered during anesthesia with propofol, nitrous oxide, oxygen and fentanyl. Neuromuscular block was measured by electromyography (single twitch stimulation every 10 s) at the larynx and the adductor pollicis. The dose-response effect measured at both muscles included maximum neuromuscular blockade achieved (Emax), the time to maximum depression of twitch height (onset) and time to spontaneous recovery of the twitch height to 25%, 75% and 90% (T25, T75, T90) of control value.

RESULT

The onset at the larynx was of 196 +/- 28 s after the 100 micro g/kg cisatracurium dose compared with 140 +/- 14 s after the 500 micro g/kg atracurium dose (P < 0.05). Emax at the larynx was 92 +/- 1% and 98 +/- 1% after 100 micro g/kg cisatracurium and 500 micro g/kg atracurium, respectively (P < 0.05). The time to onset of maximum suppression Emax = 100 +/- 0% after a 150 micro g/kg cisatracurium dose was 148 +/- 29 s. At the larynx, the ED(50) was 25 micro g/kg for cisatracurium and 180 micro g/kg for atracurium and the ED(95) was 87 micro g/kg for cisatracurium compared with 400 micro g/kg for atracurium.

CONCLUSION

The slow onset time at the laryngeal muscles after cisatracurium can be explained by the higher potency as compared with atracurium.

[The case of diagnostic difficulties of submucous myoma in early pregnancy]

The authors describe observed case of pregnancy and degenerative submucous myoma. Diagnostic difficulties.

Comparison between the Datex-Ohmeda M-NMT module and a force-displacement transducer for monitoring neuromuscular blockade

BACKGROUND AND OBJECTIVE

The Datex-Ohmeda neuromuscular transmission module (M-NMT) is a new monitor that is part of the AS/3 anaesthesia monitor. It incorporates a mechanosensor, which is a piezoelectric polymer attached to the hand. The module was compared with a force transducer in 30 patients requiring neuromuscular blockade.

METHODS

Anaesthesia was induced with fentanyl and propofol, and tracheal intubation was performed without muscle relaxants. Neuromuscular blockade was assessed by the test module on one arm and the force transducer on the other arm. When the response to train-of-four stimulation had been stable in both arms for 3 min, rocuronium 0.2 mg kg(-1) was injected intravenously. During recovery from blockade, the train-of-four ratio was measured in 15 patients, and the ratio of response to double-burst stimulation in the other 15 patients. Data analysis was by difference plots.

RESULTS

Both devices had acceptable coefficients of repeatability. The M-NMT module was biased by + 1.3% (upper limit of agreement 14.2%, lower limit -12.9%) for the recovery of the train-of-four ratio, and by + 1.09% (17%, -16%) for the recovery of double-burst stimulation ratio.

CONCLUSIONS

The Datex-Ohmeda M-NMT gives measurements that are repeatable and gives good enough correspondence with a force transducer that it can be used clinically to assess recovery of neuromuscular blockade, but the limits of agreement rule out research applications.

Effect of metoclopramide on mivacurium-induced neuromuscular block

In order to investigate the effect of metoclopramide on the duration of action of mivacurium, 45 patients were randomized into three groups. Group M10 (n = 15) and M20 (n = 15) received 10 and 20 mg of metoclopramide i.v., respectively, and group S (n = 15) received saline 2 min before induction of anesthesia with fentanyl, thiopental and mivacurium. Plasma cholinesterase activity (pCHE) was measured before induction of anesthesia and 2 min after injection of metoclopramide and saline. Neuromuscular block was monitored by a force transducer using train of four nerve stimulation. Anesthesia was maintained with isoflurane and N2O. Time to recovery of a twitch height of 90% was significantly prolonged in group M10 and M20 (44 +/- 15 and 57 +/- 10 min) as compared to group S, 32 +/- 9 min, P < 0.05). A slight but significant decrease in pCHE was observed in group M20. Because of the risk of prolonged duration of action of mivacurium, neuromuscular blockade should always be monitored whenever metoclopramide is given before injection of mivacurium.

Differential sensitivity of abdominal muscles and the diaphragm to mivacurium: an electromyographic study

BACKGROUND

Respiratory muscles are considered to be more resistant to muscle relaxants as compared with peripheral muscles. However, the relative sensitivity of respiratory muscles participating to the pump function has not been compared. We used electromyography to compare pharmacodynamic parameters of the diaphragm and abdominal muscles after mivacurium.

METHODS

Forty adults undergoing elective surgery were randomly allocated in five dosing groups of mivacurium (50, 100, 150, 200, and 250 microg/kg). Patients anesthetized with propofol and fentanyl underwent intubation without relaxants. Anesthesia was maintained with nitrous oxide and propofol. The right phrenic nerve, the left 10th intercostal nerve, and the ulnar nerve were stimulated. Electromyography of the diaphragm and abdominal muscles was recorded from surface electrodes. Mechanomyography was used to measure adductor pollicis evoked contraction. After a 5-min stable recording period, patients received a single intravenous bolus (20 s) dose of mivacurium. By using log dose-probit effect regression analysis, dose-response curves were constructed. Effective doses and 95% confidence intervals were derived for the diaphragm and abdominal muscles and were compared.

RESULTS

The dose-response regression line of abdominal muscles differed from that of the diaphragm. Calculated ED50 and ED90 were higher for the diaphragm than for the abdominal muscles (104 [82-127] and 196 [177-213] microg/kg, and 67 [51-82] and 161 [143-181] microg/kg, respectively). The onset of block was faster and recovery of control responses were shorter at the diaphragm than at the abdominal muscles.

CONCLUSION

Diaphragm and abdominal muscles have differential sensitivity to mivacurium. The diaphragm is more resistant to mivacurium than abdominal muscles are.

Intracuff pressure and tracheal morbidity: influence of filling with saline during nitrous oxide anesthesia

BACKGROUND

Diffusion of nitrous oxide into the cuff of the endotracheal tube results in an increase in cuff pressure. Excessive endotracheal tube cuff pressure may impair tracheal mucosal perfusion and cause tracheal damage and sore throat. Filling the cuff of the endotracheal tube with saline instead of air prevents the increase in cuff pressure due to nitrous oxide diffusion. This method was used to test whether tracheal morbidity is related to excess in tracheal cuff pressure during balanced anesthesia.

METHODS

Fifty patients with American Society of Anesthesiologists physical status I or II were randomly allocated to two groups with endotracheal tube cuffs initially inflated to 20-30 cm H(2)O with either air (group A) or saline (group S). Anesthesia was maintained with isoflurane and nitrous oxide. At the time of extubation, a fiberoptic examination of the trachea was performed by an independent observer, and abnormalities of tracheal mucosa at the level of the cuff contact area were scored. Patients assessed their symptoms (sore throat, dysphagia, and hoarseness) at the time of discharge from the postanesthesia care unit and 24 h after extubation on a 101-point numerical rating scale.

RESULTS

Cuff pressure increased gradually during anesthesia in group A but remained stable in group S. The incidence of sore throat was greater in group A than in group S in the postanesthesia care unit (76 vs. 20%) and 24 h after extubation (42 vs. 12%; P < 0.05). Tracheal lesions at time of extubation were seen in all patients of group A and in eight patients (32%) of group S (P < 0.05).

CONCLUSION

Excess in endotracheal tube cuff pressure during balanced anesthesia due to nitrous oxide diffusion into this closed gas space causes sore throat that is related to tracheal mucosal erosion.

[Large uterine myoma during pregnancy and delivery - choice of management]

There are scanty of available data about the management of myoma of the uterus during pregnancy and birth. The authors describe two cases of such a pathology--big myoma of the uterus > 10 sm diameter (d.), who were treated conservatively and ended successfully, without serious complications. The pregnant women were done cesarean section and during the operation the myomas were excisiert. There were no complications intra- and postoperationem. The authors suggest that myectomy during pregnancy and cesarean section must not be don routinely.

[Sensitivity to atracurium in the lateral abdominal muscles]

OBJECTIVE

To study the effect of atracurium on the electromyographic activity of the lateral abdominal muscles and adductor pollicis in anaesthetized subjects.

STUDY DESIGN

Prospective, comparative, open study.

PATIENTS AND METHODS

Sixteen patients, ASA physical status 1 or 2, undergoing elective orthopaedic surgery under general anaesthesia were studied. Anaesthesia was induced with propofol/fentanyl and orotracheal intubation performed after glottic local anaesthesia without using muscle relaxant. Anaesthesia was maintained with isoflurane/nitrous oxide/oxygen and fentanyl reinjections. Supramaximal percutaneous stimulations in a simple twitch mode (0.1 Hz) were applied at the 9th-10th intercostal nerve on the posterior axillary line and at the ulnar nerve at the wrist. The electromyographic responses were registered using skin surface electrodes, placed on the D9-D10 dermatome in regard of the lateral abdominal muscles and of the thenar muscles. After a single bolus dose of atracurium 0.5 mg.kg-1, the following parameters were studied: the maximum effect (Emax), the time for obtaining Emax (Delay) and the recovery time of 5, 10, 25, 50, 75 and 100% of the control neuromuscular response (T5, T10, T25, T50, T75, T100).

RESULTS

The dose of 0.5 mg.kg-1 of atracurium induced 100% block in both lateral abdominal muscles and adductor pollicis. Lateral abdominal muscles blockade had faster onset (136 +/- 4 s versus 205 +/- 29 s) and shorter recovery, T5, T10, T25, T50, T75 and T100 were significantly (p < 0.05) shorter than at the adductor pollicis.

CONCLUSION

Lateral abdominal muscles blockade have faster onset and recovery than adductor pollicis.

[Effectiveness of low mivacurium if its injection is postponed by a non-invasive pressure determination on the homolateral arm]

OBJECTIVE

We assessed the neuromuscular characteristics of 0.2 mg.kg-1 of mivacurium while its injection was concomitant to a non invasive blood pressure measurement in the ipsilateral arm.

PATIENTS

Thirty-one patients ASA I-II were randomized into two groups. Group cuff (n = 15) and Group control (n = 16).

METHODS

General anaesthesia was induced with fentanyl, thiopentone and mivacurium in all patients, however in the cuff group, measurement of non invasive blood pressure was performed immediately after the injection of mivacurium. Comparison was made on neuromuscular blockade of the adductor pollicis (AP) by mechanomyography, and intubating conditions which were guided by the visual estimation of the orbicularis oculi's (OO) response.

RESULTS

In the cuff group, six out of 15 patients did not have complete blockade at the OO against one out of 16 in the control group, (Fisher exact test p < 0.05). Intubation time was significantly delayed in the cuff group, 201 +/- 66 s versus 123 +/- 32 s in the control group, (t test p < 0.001). The maximum neuromuscular blocking effect at the AP was significantly greater in the control group 99 +/- 2% against 89 +/- 7% in the cuff group, (t test p < 0.01). The onset of maximum blockade at the AP was longer in the cuff group 294 +/- 40 s versus 179 +/- 92 s, (t test p < 0.001] in the control group. Time to 25% recovery was shorter in the cuff group 16 +/- 3 min versus 20 +/- 5 min, in the control group (t test p < 0.05).

CONCLUSION

This study suggests that non invasive blood pressure measurement of the ipsilateral arm, concomitant to the injection of mivacurium decreases the potency of mivacurium. This finding is mostly explained by the early hydrolysis of mivacurium in the plasma of the excluded arm.

The mechanism of pancuronium potentiation of mivacurium block: use of the isolated-arm technique

The neuromuscular blocking effects of mivacurium are greatly enhanced when mivacurium is preceded by a subparalyzing dose of pancuronium. The mechanism of this potentiation has not been elucidated. This study investigated the effects of the anticholinesterase activity of a small dose of pancuronium on the neuromuscular blocking effects of mivacurium. Forty patients were enrolled in the study. The neuromuscular effects of 7.5 and 15 microg/kg pancuronium, followed by 50 and 100 microg/kg mivacurium, were assessed in Groups PM1 and PM2 (n = 20), respectively. The neuromuscular effects of 65 and 130 microg/kg mivacurium were assessed in Groups M1 and M2 (n = 20), respectively. One arm was excluded from circulation with a tourniquet, which was inflated before the injection of pancuronium and deflated 3 min after the injection of mivacurium. The plasma cholinesterase activity was measured before induction for all patients and 3 min after the injection of pancuronium for Groups PM1 and PM2. The plasma cholinesterase activity was decreased by 16% and 33% after pancuronium administration in Groups PM1 and PM2, respectively. In the nonexcluded arm, pancuronium significantly potentiated the effects of mivacurium. In the excluded arm, no significant block was detected for Groups M1 and M2, whereas the maximal degree of neuromuscular block was 79% and 100% for Groups PM1 and PM2, respectively. Using the isolated-arm technique, we suggest that pancuronium potentiation of the neuromuscular blocking effects of mivacurium is more likely attributable to an increase in the effective plasma concentration of mivacurium than to occupancy of postsynaptic acetylcholine receptors.

IMPLICATIONS

Using the isolated-arm technique, we suggest that pancuronium potentiation of the neuromuscular blocking effects of mivacurium is more likely attributable to an increase in the effective plasma concentration of mivacurium than to occupancy of postsynaptic acetylcholine receptors.

Sentinel lymph node biopsy in cutaneous melanoma: the WHO Melanoma Program experience

BACKGROUND

We report the experience of the World Health Organization (WHO) Melanoma Program concerning sentinel lymph node (SLN) biopsy for detecting patients with occult regional nodal metastases to submit to selective regional node dissection.

METHODS

From February 1994 to August 1998, in 12 centers of the WHO Melanoma Program, 892 SLN biopsies were performed in 829 patients with clinical stage I melanoma (male: 370; female: 459; median age: 50 years old). The location of the primary melanoma was as follows: trunk 35%; lower limbs, 45%; upper limbs, 18%; and head and neck, 2%. Blue dye injection for SLN identification was performed in all cases; preoperative lymphoscintigraphy was done in 440 patients, and an intra-operative probe for a radio-guided biopsy was used in 141 cases. Overall, the SLN identification rate was 88%. In 68% of the patients, only one SLN was identified, whereas two and three or more SLN were detected in 24% and 8% of the remaining cases, respectively.

RESULTS

Overall SLN positivity rate was 18%. Intra-operative frozen section examination was performed in 39% of the cases and was helpful in detecting occult localizations only in 47% of the positive SLNs. Distribution of positive cases by primary thickness was as follows: < 1mm: 2%; 1-1.99 mm: 7%; 2-2.99 mm: 13%; and > or = 3 mm: 31%. Positive nonsentinel lymph nodes were found in 22% of cases with positive SLN submitted for selective dissection. No complications due to the procedure were registered. Of 710 patients who were evaluated, 40 (6%) presented a regional nodal relapse after a negative SLN biopsy and underwent a delayed therapeutic dissection. From the 710 enrolled cases, 638 (88.5%) were alive without evidence of disease at the time of this writing. A multivariate analysis showed SLN status as one of the most significant prognostic factors (P = .000) along with thickness (P = .001) and ulceration (P = .015) of primary tumor.

CONCLUSIONS

These data confirm the feasibility and safety of the SLN technique for selecting patients to submit to a radical node dissection. The data represent the basis for a future trial by the WHO Melanoma Program in this field to evaluate the most appropriate surgical approach for treating patients with occult regional nodal metastases.

[The Joel-Cohen (Misgav Ladach) method--a new surgical technic for cesarean section and gynecological laparotomy]

The authors make a review on this problem for first time in Bulgarian literature and for the first time by us operated with the Misgav Ladach method--cesarean section. The authors describe 50 cases wit Ladach method and as control 20 with Pfannenstiel. The authors establish shorter duration of the operation-Si] and 56.3 min. respective in benefit for Misgav method; the babies were extracted at 5.5 and 12.3 min. respect. The mothers with Misgav had better prognosis at the time of dehospitalization.

Effects of an intubating dose of succinylcholine and rocuronium on the larynx and diaphragm: an electromyographic study in humans

BACKGROUND

Paralysis of the vocal cords is one objective of using relaxants to facilitate tracheal intubation. This study compares the neuromuscular blocking effect of succinylcholine and rocuronium on the larynx, the diaphragm, and the adductor pollicis muscle.

METHODS

Electromyographic response was used to compare the neuromuscular blocking effect of succinylcholine and rocuronium on the laryngeal adductor muscles, the diaphragm, and the adductor pollicis muscle. Sixteen patients undergoing elective surgery were anesthetized with propofol and fentanyl, and their tracheas were intubated without neuromuscular blocking agents. The recurrent laryngeal and phrenic nerves were stimulated at the neck. The electromyographic response was recorded from electrodes placed on the endotracheal tube and intercostally before and after administration of 1 mg/kg succinylcholine or 0.6 mg/kg rocuronium.

RESULTS

The maximum effect was greater at the adductor pollicis (100 and 99%) than at the larynx (96 and 97%) and the diaphragm (94 and 96%) after administration of succinylcholine and rocuronium, respectively (P < or = 0.05). Onset time was not different between the larynx (58+/-10 s), the diaphragm (57+/-8 s), and the adductor pollicis (54+/-13 s), after succinylcholine (all mean +/- SD). After rocuronium, onset time was 124+/-39 s at the larynx, 130+/-44 s at the diaphragm, and 115+/-21 s at the adductor pollicis. After succinylcholine administration, time to 90% recovery was 8.3+/-3.2, 7.2+/-3.5, and 9.1+/-3.0 min at the larynx, the diaphragm, and the adductor pollicis, respectively. Time to 90% recovery after rocuronium administration was 34.9+/-7.6, 30.4+/-4.2, and 49.1+/-11.4 min at the larynx, the diaphragm, and the adductor pollicis, respectively.

CONCLUSION

Neuromuscular blocking effect of muscle relaxants on the larynx can be measured noninvasively by electromyography. Although the larynx appears to be resistant to muscle relaxants, we could not demonstrate that its onset time differed from that of peripheral muscles.

Religious faith after psychotic illness

Religion can play an important role in the lives of psychiatric patients. We assessed how often a psychotic illness can lead to a change in the strength of religious faith and how commonly religion is used for coping with such illnesses in a sample of consecutively admitted patients. 52 patients with psychosis were interviewed regarding their religious beliefs after their index admission. 69.4% of the patients were religious, and 11 (22.4%) stated that religion was the most important part of their lives. 30.4% of the sample described that there had been an increase in their religiousness after the onset of illness. 61.2% of patients were using their religion for coping with the illness. Such patients had a better insight into their illness and were more compliant with antipsychotic medication. We conclude that the experience of a psychotic illness is likely to lead to an increase in religious beliefs. Such beliefs are commonly used for coping with the illness and some patients attach a great importance to them.

Comparison of the effects of mivacurium on the diaphragm and geniohyoid muscles

Although subjects often report difficulty with swallowing shortly after receiving neuromuscular blocking agents, difficulty with swallowing during recovery from neuromuscular blocking agents appears to be infrequent. We have used electromyography to compare onset and recovery at the diaphragm and geniohyoid airway muscles after an intubating dose of mivacurium (0.2 mg kg-1) to determine if the geniohyoid muscles were particularly sensitive to neuromuscular blocking agents. Twelve adults undergoing elective surgery were anaesthetized with propofol and fentanyl and the trachea intubated without neuromuscular blocking agents. The left hypoglossal and right phrenic nerves were stimulated with percutaneous needle electrodes and the electromyogram recorded with surface electrodes. EMG responses were measured after a bolus dose of mivacurium 0.2 mg kg-1. Recordings were also made of the mechanical response of the adductor pollicis to supramaximal ulnar nerve stimulation. There was no difference in the rate of onset of block for geniohyoid muscles and the diaphragm, but recovery to 25% and 90% of the control response was shorter at the diaphragm (median 14.5 (95% confidence limits 12.9-15.3) min and 23.8 (21.7-26) min) than at the geniohyoid muscle (19.4 (15.6-20.1) min and 29.2 (26.3-31.4) min), respectively (P < 0.05). When the train-of-four ratio of the mechanical response of the thumb reached 70%, the diaphragm and geniohyoid muscles had recovered completely in all patients.

Correlation between concentration of cholinesterases and the resistance of animals to organophosphorus compounds

The molar concentrations of the catalytic sites of serum cholinesterase (ChE--EC 3.1.1.8.) and cholinesterases (ChEs-acetylcholinesterase (AChE)--EC 3.1.1.7. and ChE) from brain and perfused liver of male birds, rats, swine and sheep were determined. A positive correlation between the molar concentrations of the catalytic sites of ChEs and the resistance of the animals to some organophosphorus compounds (OPhCs) was found. In addition, the present study also showed that the difference of the molar concentrations of catalytic sites of ChEs in the brain, blood serum and liver can cause varied resistance to some OPhCs.

Studies of the course of schizophasia

The course of psychoses of schizophrenic type follows rules which are still not adequately understood. It is, however, clear that certain symptoms appear mostly early, others only late. With this hypothesis in mind, we studied 44 final phase patients whose main symptom was disordered thinking of the schizophasic type and whose illness was of at least 10 years' standing. The most important finding of this study is that the varied and unspecific initial phase progresses into a highly specific syndrome. The symptoms initially registered include various disorders of thinking in less than one third of patients. In no case did these involve schizophasia. In a second phase symptoms were observed such as paralogism, echolalia, verbigeration, circumstantiality, neologism, hypotonic thinking, perseveration, blocking. The symptoms of schizophasia are only recognizable in a third phase and are highly specific. This enables us to confute the claim that psychiatric syndromes are not clinically specific. The three phases described above also provide evidence for the biological nature of this endogenous psychosis.

Aggressiveness, anxiety and drugs

Aggression and anxiety are among the most common phenomena needing medical control, especially in acute mental disorders. Today we can choose from a confusingly large array of drugs which can quickly control these two kinds of emotional and behavioural disorders. Everyday practice shows that these two groups of symptoms, seemingly so different from one another, can be treated with the same drugs. If we probe more deeply into the matter, we find that the similarities in these effects include not only inhibition of aggressiveness and anxiety but also their enhancement, activation, and provocation. These effects seem to form a regular pattern: those that increase aggressiveness (sympathicomimetics, catecholamines, ‘activating’ antidepressants, psychostimulants, and anti-Parkinsonics (cholinolytics)) also tend to increase anxiety, while those that decrease aggressiveness (beta-blockers, neuroleptics (major tranquillisers), ‘sedative’ antidepressants, minor tranquilisers, hypnotics, analgesics, and anticonvulsants) also tend to decrease anxiety.

Long-term study of schizophasic patients

The hypothesis that some symptoms of schizophrenia only manifest in the early stages whereas others only appear later is tested with 33 inpatients in 'terminal states'. It is found that while the onset shows no specificity, the outcome is very typical. The initial symptoms are polymorphous; thought disorders can be found in less than one third of the patients and frank incoherence approaching the severity of schizophasia not at all. Many years later appear symptoms registered as paralogism, echolalia, verbigeration, stilted speech, neologism, hypotonic thinking, retardation, derailment, and incongruous answers. Only then, sometimes 25 years after the onset of the illness, the peculiar and highly specific picture of the schizophasic disorder becomes established.

[Schizophrenic and paranoid - bi- or trisection of endogenous psychoses]

The fundamental differences between the syndromes united under the term of schizophrenia are demonstrated. Attempts to reduce these syndromes to a common denominator of a nosological unit bearing the same designation have failed. Important arguments are advanced against the identification, widespread in practice, of the terms "paranoid" and "schizophrenic". It is pointed out that these two terms are incompatible to some extent. There is a fundamental difference between the nature of paranoia and the symptoms characteristic of schizophrenia (Dementia praecox). Paranoia is far more dependent on the personality than on the pathological process. A division into three aspects - schizophrenia, paranoid psychoses and MDP instead of the dichotomy schizophrenia/MDP, is proposed for a better theoretical and practical understanding in the field of endogeny. Further semantic arguments are advanced against the term "schizophrenia" indicating its iatrogenic effect.