Influence of Hyperoxic-Supplemented High-Intensity Interval Training on Hemotological and Muscle Mitochondrial Adaptations in Trained Cyclists

Background: Hyperoxia (HYPER) increases O₂ carrying capacity resulting in a higher O₂ delivery to the working muscles during exercise. Several lines of evidence indicate that lactate metabolism, power output, and endurance are improved by HYPER compared to normoxia (NORM). Since HYPER enables a higher exercise power output compared to NORM and considering the O₂ delivery limitation at exercise intensities near to maximum, we hypothesized that hyperoxic-supplemented high-intensity interval training (HIIT) would upregulate muscle mitochondrial oxidative capacity and enhance endurance cycling performance compared to training in normoxia. Methods: 23 trained cyclists, age 35.3 ± 6.4 years, body mass 75.2 ± 9.6 kg, height 179.8 ± 7.9 m, and VO₂max 4.5 ± 0.7 L min^-1 performed 6 weeks polarized and periodized endurance training on a cycle ergometer consisting of supervised HIIT sessions 3 days/week and additional low-intensity training 2 days/week. Participants were randomly assigned to either HYPER (F_IO₂ 0.30; n = 12) or NORM (F_IO₂ 0.21; n = 11) breathing condition during HIIT. Mitochondrial respiration in permeabilized fibers and isolated mitochondria together with maximal and submaximal VO₂, hematological parameters, and self-paced endurance cycling performance were tested pre- and posttraining intervention. Results: Hyperoxic training led to a small, non-significant change in performance compared to normoxic training (HYPER 6.0 ± 3.7%, NORM 2.4 ± 5.0%; p = 0.073, ES = 0.32). This small, beneficial effect on the self-paced endurance cycling performance was not explained by the change in VO₂max (HYPER 1.1 ± 3.8%, NORM 0.0 ± 3.7%; p = 0.55, ES = 0.08), blood volume and hemoglobin mass, mitochondrial oxidative phosphorylation capacity (permeabilized fibers: HYPER 27.3 ± 46.0%, NORM 16.5 ± 49.1%; p = 0.37, ES = 3.24 and in isolated mitochondria: HYPER 26.1 ± 80.1%, NORM 15.9 ± 73.3%; p = 0.66, ES = 0.51), or markers of mitochondrial content which were similar between groups post intervention. Conclusions: This study showed that 6 weeks hyperoxic-supplemented HIIT led to marginal gain in cycle performance in already trained cyclists without change in VO₂max, blood volume, hemoglobin mass, mitochondrial oxidative phosphorylation capacity, or exercise efficiency. The underlying mechanisms for the potentially meaningful performance effects of hyperoxia training remain unexplained and may raise ethical questions for elite sport.

Craniomaxillofacial osteosarcoma - The role of surgical margins

BACKGROUND

Osteosarcomas (OS) in the craniomaxillofacial (CMF) region are typically diagnosed at later age than long-bone OS, but they are reported to have better 5-year survival. Curative treatment warrants wide surgical resection, which is often not possible in the CMF region. The purpose of this article is to present a nationwide series of CMF in Finland to discuss the role of surgery.

PATIENTS AND METHODS

All 21 CMF OS patients managed in Finland from 1992 to 2009 were included. The mean age was 40 years (range 15-72). Data on patient and tumor characteristics, treatment modalities, and survival were recorded. All patients had a minimum follow-up of 5 years or until death.

RESULTS

OS was evenly represented in the mandible and maxillary bones, which together constituted 76% of all sites. Surgery with curative intent was carried out in 20 patients. Clear margins were achieved in only five cases. Eight (40%) of these 20 patients died due to OS, and their average survival time was 1.3 years. Seven (35%) out of the 20 patients received radiotherapy due to close/intralesional surgical margins, and four of them did not develop recurrences during the follow-up.

CONCLUSIONS

The results suggest that postoperative radiotherapy may alter the prognosis in CMF OS, particularly in cases with close or intralesional margins. This may increase the survival rates achieved by prompt action in performing radical surgery.

Autoregressive Modeling with Exogenous Input of Middle-Latency Auditory-Evoked Potentials to Measure Rapid Changes in Depth of Anesthesia

Obtaining an adequate depth of anesthesia is a continuous challenge to the anesthetist. With the introduction of muscle-relaxing agents the traditional signs of awareness are often obscured, or difficult to interpret. These signs include blood pressure, heart rate, pupil size, etc. However, these factors do not describe the depth of anesthesia (DA) in a cerebral activity sense. Hence, a better measure of the DA is required. It has been suggested that Auditory-Evoked Potentials (AEP) can provide additional information about the DA. The general method of extracting AEP is by use of a Moving Time Average (MTA). However, the MTA is time consuming because a large number of repetitions is needed to produce an estimate of the AEP. Hence, changes occurring over a small number of sweeps will not be detected by the MTA average. We describe a system-identification method, an autoregressive model with exogeneous input (ARX) model, to produce a sweep-by-sweep estimate of the AEP. The method was clinically evaluated in 10 patients anesthetized with alfentanil and propofol. The time interval between propofol induction and the time when the Na-Pa amplitude was decreased to 25% of the initial amplitude was measured. These measurements showed that ARX-estimated compared to MTA-estimated AEP was significantly faster in tracing transition from consciousness to unconsciousness during propofol induction (p <0.05).

On-line Analysis of AEP and EEG for Monitoring Depth of Anaesthesia

Achieving and monitoring adequate depth of anaesthesia is a challenge to the anaesthetist. With the introduction of muscle relaxing agents, the traditional signs of awareness are often obscured or difficult to interpret. These signs include blood pressure, heart rate, pupil size, etc. However, these factors do not describe the depth of anaesthesia, (DA), in a cerebral activity sense, hence there is a desire to achieve a better measure of the DA. Auditory Evoked Potentials (AEP) provide two aspects relevant to - anaesthesia: (1) they have identifiable anatomical significance and, (2) their characteristics reflect the way in which the brain reacts to a stimulus. However, AEP is embedded in noise from the ongoing EEG background activity. Hence, processing is needed to improve the signal to noise ratio. The methods applied were moving time averaging (MTA) and ARX-modeling. The EEG was collected from the left hemisphere and analysed by FFT to 1 sec epochs and the spectral edge frequency was calculated. Both the changes in ARX extracted AEP and the spectral edge frequency of the EEG correlated well with the time interval between propofol induction and onset of anaesthesia measured by clinical signs (i.e., cessation of eye-lash reflex). The MTA extracted AEP was significantly slower in tracing the transition from consciousness to unconsciousness.

The analgesic effect of therapeutic rTMS is not mediated or predicted by comorbid psychiatric or sleep disorders

BACKGROUND

Mechanisms underlying alleviation of neuropathic pain by repetitive transcranial magnetic stimulation (rTMS) of primary motor cortex (M1) and right secondary somatosensory cortex (S2) are only partly known. Patients with chronic neuropathic pain often have comorbidities like depression and sleep problems. Through functional connectivity, rTMS of M1 and S2 may activate dorsolateral prefrontal cortex, the target for treating depression with rTMS. Thus, the analgesic effect of rTMS could be mediated indirectly via improvement of psychiatric comorbidities or sleep. We examined whether rTMS has an independent analgesic effect or whether its clinical benefits depend on effects on mood or sleep. We also evaluated if comorbid psychiatric or sleep disorders predict the treatment outcome.

METHODS

Sixteen patients with chronic drug-resistant neuropathic orofacial pain participated in this randomized controlled crossover rTMS study. Patients' psychiatric history was evaluated by a specialist in psychiatry. Intensity and interference of pain, mood, and the quality of sleep and life were evaluated at baseline and after 2 active (primary somatosensory cortex [S1]/M1 and S2) and placebo rTMS treatments. A logistic regression analysis was done to investigate predictors of treatment outcome.

RESULTS

The analgesic effect of the right S2 stimulation was not associated with improvement of psychiatric conditions or sleep, whereas S1/M1 stimulation improved sleep without significant analgesic effect (P = 0.013-0.046 in sleep scores). Psychiatric and sleep disorders were more common in patients than in the general population (P = 0.000-0.001 in sleep scores), but these comorbidities did not predict the rTMS treatment outcome.

CONCLUSION

We conclude that rTMS to the right S2 does not exert its beneficial analgesic effects in chronic neuropathic orofacial pain via indirect improvement of comorbid psychiatric or sleep disorders.

Right secondary somatosensory cortex-a promising novel target for the treatment of drug-resistant neuropathic orofacial pain with repetitive transcranial magnetic stimulation

High-frequency repetitive transcranial magnetic stimulation (rTMS) of the motor cortex has analgesic effect; however, the efficacy of other cortical targets and the mode of action remain unclear. We examined the effects of rTMS in neuropathic orofacial pain, and compared 2 cortical targets against placebo. Furthermore, as dopaminergic mechanisms modulate pain responses, we assessed the influence of the functional DRD2 gene polymorphism (957C>T) and the catechol-O-methyltransferase (COMT) Val158Met polymorphism on the analgesic effect of rTMS. Sixteen patients with chronic drug-resistant neuropathic orofacial pain participated in this randomized, placebo-controlled, crossover study. Navigated high-frequency rTMS was given to the sensorimotor (S1/M1) and the right secondary somatosensory (S2) cortices. All subjects were genotyped for the DRD2 957C>T and COMT Val158Met polymorphisms. Pain, mood, and quality of life were monitored throughout the study. The numerical rating scale pain scores were significantly lower after the S2 stimulation than after the S1/M1 (P = 0.0071) or the sham (P = 0.0187) stimulations. The Brief Pain Inventory scores were also lower 3 to 5 days after the S2 stimulation than those at pretreatment baseline (P = 0.0127 for the intensity of pain and P = 0.0074 for the interference of pain) or after the S1/M1 (P = 0.001 and P = 0.0001) and sham (P = 0.0491 and P = 0.0359) stimulations. No correlations were found between the genetic polymorphisms and the analgesic effect in the present small clinical sample. The right S2 cortex is a promising new target for the treatment of neuropathic orofacial pain with high-frequency rTMS.

A Pilot Study on the Influence of Facial Expression on Measurements in Three-Dimensional Digital Surfaces of the Face in Infants With Cleft Lip and Palate

OBJECTIVE

Three-dimensional surface imaging is an increasingly popular modality for face measurements in infants with cleft lip and palate. Infants are noncompliant toward producing specific facial expressions, and selecting the appropriate moment of acquisition is challenging. The objective was to estimate amount and spatial distribution of deformation of the face due to facial expression in infants with cleft lip and palate and provide recommendations for an improved acquisition protocol, including a method of quality control in terms of obtaining images with true neutral expression.

MATERIAL AND METHODS

Three-dimensional surface images of ten 4-month-old infants with unrepaired cleft lip and palate were obtained using a 3dMDface stereophotogrammetric system. For each subject, five surface images judged as representing a neutral expression were obtained during the same photo session. Mean and maximum deformations were calculated. A formalized review was performed, allowing the image exhibiting the "best" neutral expression to be selected, thus decreasing errors due to residual facial expression.

RESULTS

Deformation due to facial expression generally increased from forehead to chin. The amount of deformation in three selected regions were determined: nose (mean, 1 mm; maximum = 3 mm); cleft region (mean, 2 mm; maximum = 5 mm); chin region (mean, 5 mm; maximum = 12 mm). Analysis indicated that introduction of a formalized review of images could reduce these errors by a factor of 2.

CONCLUSIONS

The continuous change of facial expression in infants represents a substantial source of error; however, this may be reduced by incorporating a formalized review into the acquisition protocol.

Neck muscle activity in skydivers during parachute opening shock

This observational study investigated skydiver neck muscle activity during parachute opening shock (POS), as epidemiological data recently suggested neck pain in skydivers to be related to POS. Twenty experienced skydivers performed two terminal velocity skydives each. Surface electromyography quantified muscle activity bilaterally from the anterior neck, the upper and lower posterior neck, and the upper shoulders; and two triaxial accelerometers sampled deceleration. Muscle activity was normalized as the percentage of reference maximum voluntary electrical activity (% MVE); and temporal muscle activity onset was related to POS onset. Our results showed that neck muscle activity during POS reached mean magnitudes of 53-104% MVE, often exceeding reference activity in the lower posterior neck and upper shoulders. All investigated muscle areas' mean temporal onsets occurred <50 ms after POS onset (9-34 ms latencies), which is consistent with anticipatory motor control. The high muscle activity observed supports that the neck is under substantial strain during POS, while temporal muscle activation suggests anticipatory motor control to be a strategy used by skydivers to protect the cervical spine from POS. This study's findings contribute to understanding the high rates of POS-related neck pain, and further support the need for evaluation of neck pain preventative strategies.

Primary metastatic Ewing's family tumors: results of the Italian Sarcoma Group and Scandinavian Sarcoma Group ISG/SSG IV Study including myeloablative chemotherapy and total-lung irradiation

BACKGROUND

The Italian Sarcoma Group and the Scandinavian Sarcoma Group designed a joint study to improve the prognosis for patients with Ewing's family tumors and synchronous metastatic disease limited to the lungs, or the pleura, or a single bone.

PATIENTS AND METHODS

The study was opened in 1999 and closed to the enrollment in 2008. The program consisted of intensive five-drug combination chemotherapy, surgery and/or radiotherapy as local treatment, and consolidation treatment with high-dose busulfan/melphalan plus autologous stem cell rescue and total-lung irradiation.

RESULTS

During the study period, 102 consecutive patients were enrolled. The median follow-up was 62 months (range 24-124). The 5-year event-free survival probability was 0.43 [standard deviation (SD) = 0.05] and the 5-year overall survival probability was 0.52 (SD = 0.052). Unfavorable prognostic factors emerging on multivariate analysis were a poor histological/radiological response at the site of the primary tumor [relative risk (RR) = 3.4], and incomplete radiological remission of lung metastases after primary chemotherapy (RR = 2.6). One toxic death and one secondary leukemia were recorded.

CONCLUSIONS

This intensive approach is feasible and long-term survival is achievable in ∼50% of patients. New treatment approaches are warranted for patients responding poorly to primary chemotherapy.

Glossopharyngeal pistoning for lung insufflation in patients with cervical spinal cord injury

STUDY DESIGN

A prospective cohort study.

OBJECTIVES

To evaluate whether patients with cervical spinal cord injury (CSCI) are able to learn the technique of glossopharyngeal pistoning (breathing) for lung insufflation (GI) and if learned, to evaluate the effects of GI on pulmonary function and chest expansion after 8 weeks.

SETTING

Karolinska University Hospital, Stockholm, Sweden.

METHODS

Twenty-five patients with CSCI (21 men, four women) with a mean age of 46 years (21-70), from the Stockholm area, were used in this study. The participants performed 10 cycles of GI four times a week, for 8 weeks. Pulmonary function tests made before and after the GI training included vital capacity (VC), expiratory reserve volume (ERV), functional residual capacity (FRC; measured with nitrogen washout), residual volume (RV) and total lung capacity (TLC). Chest expansion was measured before and after training.

RESULTS

Five of the twenty-five participants had difficulty in performing GI and were excluded in further analysis. Performing a GI maneuvre increased participants' VC on average by 0.88+/-0.5 l. After 8 weeks of training, the participants had significantly increased their VC 0.23 l, (P<0.001), ERV 0.16 l, (P<0.01), FRC 0.86 l, (P<0.001), RV 0.70 l, (P<0.001) and TLC 0.93 l, (P<0.001). Chest expansion increased at the level of the xiphoid process by 1.2 cm (P<0.001) and at the level of the fourth costae by 0.7 cm (P<0.001).

CONCLUSIONS

After using GI for a period of 8 weeks, the participants with CSCI who could perform GI were able to improve pulmonary function and chest expansion.

Cardiovascular aspects of glossopharyngeal insufflation and exsufflation

Breath-hold divers use glossopharyngeal breathing to inhale above total lung capacity (glossopharyngeal insufflation, GI) or exhale below residual volume (glossopharyngeal exsufflation, GE). In these maneuvers, air is moved using glossopharyngeal rather than respiratory muscle activity. Four competitive divers performed several GI and GE maneuvers in sitting or standing position, while cardiovascular parameters were measured with a photoplethysmographic method; echocardiography was also performed during GE. During GI, the divers showed a 48% drop in mean arterial pressure (MAP) to 50 mmHg, with a 88% decrease in pulse pressure (PP), while heart rate (HR) increased by 36% to 103 beats/min and cardiac output (CO) dropped by 79% to 1.3 l/min. The increase in intrathoracic pressure during GI, measured in separate experiments, is probably responsible for these hemodynamic changes, by impeding venous return into the chest. Associated with the drop in MAP during GI were various neurological signs and symptoms, including dizziness, tunnel vision, involuntary twitching of facial muscles and one brief episode of loss of consciousness. During GE, initially MAP and PP increased by 36% and 61%, to 149 and 95 mmHg respectively; later HR decreased by 37% to 45 beats/min and CO dropped by 37% to 4.3 l/min. The early cardiovascular changes of GE may be related to a decrease in intrathoracic pressure, enhancing venous return, as shown by a 6 to 15% increase in end-diastolic diameter; later changes are similar to the responses to apnea at low lung volumes. Because of their hemodynamic effects, these breathing maneuvers should be performed with caution, particularly in the case of GI.

Resistive respiratory muscle training improves and maintains endurance swimming performance in divers

Respiratory work is increased during exercise under water and may lead to respiratory muscle fatigue, which in turn can compromise swimming endurance. Previous studies have shown that respiratory muscle training, conducted five days per week for four weeks, improved both respiratory and fin swimming endurance. This training (RRMT-5) consisted of intermittent vital capacity breaths (twice/minute) against spring loaded breathing valves imposing static and resistive loads generating average inspiratory pressures of approximately 40 cmH2O and expiratory pressures of approximately 47 cmH2O. The purpose of the present study (n = 20) was to determine if RRMT 3 days per week (RRMT-3) would give similar improvements, and if continuing RRMT 2 days per week (RRMT-M) would maintain the benefits of RRMT-3 in fit SCUBA divers. Pulmonary function, maximal inspiratory (P(insp)) and expiratory pressures (P(exp)), respiratory endurance (RET), and surface and underwater (4 fsw) fin swimming endurance were determined prior to and after RRMT, and monthly for 3 months. Pulmonary function did not significantly improve after either RRMT-3 or RMMT-5; while P(insp) (20 and 15%) and P(exp) (25 and 11%), RET (73 and 217%), surface (50 and 33%) and underwater (88 and 66%) swim times improved. VO2, VE and breathing frequency decreased during the underwater endurance swims after both RRMT-3 and RRMT-5. During RRMT-M P(insp) and P(exp) and RET and swimming times were maintained at post RRMT-3 levels. RRMT 3 or 5 days per week can be recommended to divers to improve both respiratory and fin swimming endurance, effects which can be maintained with RRMT twice weekly.

Loss of Motor Control and/or Loss of Consciousness during Breath-Hold Competitions

Since the first official world championships in breath-hold diving (1996), a sport has developed where the athletes compete in various disciplines of breath-hold diving. One of the rules is that the diver should surface from a dive without showing any signs of hypoxia. Depending on the severity of hypoxia, a diver may suffer disqualifying signs such as loss of consciousness (LOC) or loss of motor control (LMC), the latter including signs such as confusion, affected postural control, spasms or speech problems. Data was collected from the results of the major international competitions following AIDA guidelines (Association International pour le Dévelopment de l'Apnée) in 1998, 2001-2004. The data was analyzed for frequency of LOC and LMC during constant weight diving and during static apnea. In constant weight diving, the diver swims down (and up) as deeply as possible along a vertically suspended rope (current record 105 m). In static apnea, the diver strives for maximum duration, floating motionless face down in a pool (current record 8.58 min). A total of 601 static apnea (SA) performances and 596 constant weight dives were judged in the six competitions. On average, 10 % of SA, and 11 % of CW performances were disqualified due to signs of hypoxia. For the competitions in 2002-2004, a distinction was made in the rules between LOC and LMC; of a total number of 355 SA performances, 1.1 % resulted in LOC, while 9.6 % resulted in LMC. For CW, the number was 344 with 6.1 % LOC and 6.1 % LMC. Despite the relatively high incidence of dramatic signs, it is noteworthy that there have been no reports of fatal accidents or permanent injuries from any of the above-mentioned competitions. This descriptive paper shows a relatively high incidence of disqualifications due to signs of hypoxia in breath-hold competitions 1998-2004.

Effects of respiratory muscle training on respiratory CO2 sensitivity in SCUBA divers

Typically, ventilation is tightly matched to CO2 production. However, in some cases CO2 is retained (SCUBA diving). One factor behind hypoventilation in divers may be low respiratory CO2 sensitivity. If this is due to inadequate respiratory muscle performance it might be remedied by respiratory muscle training (RMT). We retrospectively investigated respiratory CO2 sensitivity prior to and after RMT in several groups of SCUBA divers. CO2 sensitivity (slope of expired ventilation as a function of inspired PCO2) was measured with a rebreathing technique in 35 subjects with diving experience. RMT consisted of either isocapnic hyperventilation or intermittent vital capacity breaths (twice/minute) against spring loaded breathing valves imposing static and resistive loads generating average inspiratory pressures of approximately 40 cmH2O and expiratory pressures of approximately 47 cmH2O; RMT was performed 30 min/day, 3 or 5 days/week for 4 weeks. Based on pre-RMT CO2 sensitivity the subjects were divided into three groups: low sensitivity: < 2 l/min/mmHg PCO2, normal: 2-4 l/min/mmHg, and high sensitivity: > 4 l/min/mmHg of inspired PCO2. The normal group had a Pre-RMT CO2 sensitivity of 2.88 +/- 0.60 and a post RMT sensitivity of 2.51 +/- 0.88 l/min/mmHg (Mean +/- SD, n = 19, p = n.s). Response in low sensitivity subjects increased from 1.41 +/- 0.32 to 2.27 +/- 0.53 (n = 10, p = 0.002,) while in the high sensitivity group it decreased from 5.41 +/- 1.25 to 2.90 +/- 0.32 l/min/mmHg (n = 6, p = 0.003). These preliminary findings showed that 46% of the subjects had abnormal sensitivity, and suggest that RMT may normalize it in hypo- and hyper-ventilating divers. If the present results are verified, RMT may be an effective means of enhancing safety in CO2 retaining divers.

Alveolar gas composition before and after maximal breath-holds in competitive divers

The urge to breathe, as stimulated by hypercapnia, is generally considered to cause a breath-hold diver to end the breath-hold, and pre-breath hold hyperventilation has been suggested to cause hypoxic loss of consciousness (LOC) due to the reduced urge to breathe. Competitors hyperventilate before "Static Apnea", yet only 10% surface with symptoms of hypoxia such as loss of motor control (LMC) or LOC. We hypothesized that the extensive hyperventilation would prevent hypercapnia even during prolonged breath-holding and we also recorded breaking-point end-tidal PO2 in humans. Nine breath-hold divers performed breath-holds of maximal duration according to their chosen "Static Apnea" procedure. They floated face down in a swimming pool (28 degrees C). The only non-standard procedure was that they exhaled into a sampling tube for end-expiratory air, before starting the breath-hold and before resuming breathing. Breath-hold duration was 284 +/- 25 (SD) seconds. End-tidal PCO2 was 18.9 +/- 2.0 mmHg before apnea and 38.3 +/- 4.7 mmHg at apnea termination. End-tidal PO2 was 131.7 +/- 2.7 mmHg before apnea and 26.9 +/- 7.5 mmHg at apnea termination. Two of the subjects showed LMC after exhaling into the sampling tube; their end-tidal PAO2 values were 19.6 and 21.0 mmHg, respectively. End-tidal CO2 was normocapnic or hypocapnic at the termination of breath-holds. These data suggest that the athletes rely primarily on the hypoxic stimuli, probably in interaction with CO2 stimuli to determine when to end breath-holds. The severity of hypoxia close to LOC was similar to that reported for acute hypobaric hypoxia in humans.

The heart rate of breath-hold divers during static apnea: effects of competitive stress

Breath-hold divers compete with regard to depth, time and/or distance. The present observations were carried out on athletes performing static apnea where they perform one breath-hold for as long a duration as possible with the body and face immersed in water. Heart rate was measured on eight competitors participating in the Swedish Championship in static apnea 2001, both during the competition and during a separate training session using the Polar NV system. The duration of apneas during the competition ranged from 3 minutes 27 seconds to 5 minutes 33 seconds. The divers exhibited significantly faster heart rates prior to and during the first 90 seconds of apnea in connection with competition, than during training. One subject experienced a loss of motor control during the competition. We suggest that mental stress in humans, caused here by a competitive situation, leads to an increase in the heart rate during apnea.

Time components of circulatory transport from the lungs to a peripheral artery in humans

Blood gas changes occurring in the lung undergo delay and damping on their way to a peripheral artery sampling site. Knowledge of the time components of circulatory transfer is important for the understanding of respiratory control and cardiovascular reflexes in response to blood gas transients. Providing steady state with regard to VA/Q distribution, cardiac output and peripheral blood flow, the relationship between the time courses of small end-tidal and peripheral PO2 changes is determined by the transfer function of the interposed vascular segment. This transfer function, expressed as delay time TD and mean transit time (MTT), was measured in six well-trained subjects, allowing the calculation of arterial time-courses from end-tidal to the reverse. They were studied at rest and during four different dynamic leg exercise intensities in the supine posture. TD and MTT amounted to 15.8 +/- 1.7 (mean +/- SEM) and 18.3 +/- 2.1 s at rest and were shortened to 7.7 +/- 0.6 and 11.5 +/- 1.8 s during exercise at 170 W. The shortening of TD and MTT did not appear to be simply an inverse function of cardiac output, suggesting that the shortening occurs in the central circulatory segment but not in the arm segment.

Effects of IKK inhibitor PS1145 on NF-κB function, proliferation, apoptosis and invasion activity in prostate carcinoma cells

A key antiapoptotic transcription factor, nuclear factor kappa-B (NF-kappaB), is known to be critically important for tumor cell growth, angiogenesis and development of metastatic lesions. We and others showed previously that NF-kappaB transcription factor was constitutively activated in androgen-independent prostate carcinoma (PC) cell lines due to the upregulated activity of inhibitor of NF-kappaB kinases (IKK). In this work, using luciferase assay, electrophoretic mobility shift assay and Northern blot analysis of expression of endogenous kappaB-responsive genes, we demonstrate that a novel highly specific small-molecule IKK inhibitor, PS1145, efficiently inhibited both basal and induced NF-kappaB activity in PC cells. We found that PS1145 induced caspase 3/7-dependent apoptosis in PC cells and significantly sensitized PC cells to apoptosis induced by tumor necrosis factor alpha. We also showed that PS1145 inhibited PC cell proliferation. Effects of PS1145 on proliferation and apoptosis correlated with inhibition of interleukin (IL)-6, cyclin D1, D2, inhibitor of apoptosis (IAP)-1 and IAP-2 gene expression and decreased IL-6 protein level. In addition, we found that incubation with PS1145 inhibited the invasion activity of highly invasive PC3-S cells in invasion chamber assay in a dose-dependent manner. Overall, this study provides the framework for development of a novel therapeutic approach targeting NF-kappaB transcription factor to treat advanced PC.

Lactation and breast-feeding ability following lateral pedicle mammaplasty

A retrospective study was undertaken to evaluate the ability of breast-feeding using lateral pedicle reduction mammaplasty. A standard questionnaire was sent to 72 patients who had been operated on at a fertile age. Data was collected regarding the duration and quality of preoperative and postoperative breast-feeding, difficulties while breast-feeding, reasons for discontinuation of breast-feeding or for not attempting to breast-feed, and postoperative subjective sensitivity. Thirteen of the women who replied to the questionnaire had given birth after surgery. The pressure threshold sensitivity of areola-nipple complex was measured in nine of the above cases. To preserve lactation, a technique leaving structures untouched within the pedicle with increased dimensions was used.Breast-feeding was considered successful in this study if it was performed exclusively, without supplementation, for two months. Seven women (54%) breast-fed successfully for between two and 14 months (5.8+/-1.3) following surgery. Two women (16%) were classified as unsuccessful and four women (30%) did not breast-feed at all. The success of breast-feeding was limited by nonsurgical factors including the influence of medical personal. Five of eight women (62%) who had children preoperatively improved their rate of breast-feeding after surgery. No correlation was demonstrated between measured sensitivity and breast-feeding (p=0.65). No significant correlation was found between the resected tissue and breast-feeding (p=0.08). No relation was observed between the duration of breast-feeding and the period between operation and partus.

A retrospective quantitative assessment of breast sensation after lateral pedicle mammaplasty

Preservation of sensitivity is one of the important objectives in reduction mammaplasty. The lateral or medial pedicle reduction mammaplasty technique aims to maintain superficial innervation of the breast. These superficial nerves are smaller and more variable compared with deep and larger nerve structures, which are excised during this procedure. An assessment of recovery of tactile sensitivity after lateral pedicle mammaplasty was performed retrospectively. One hundred and one women, operated on between the year 1985 and 2000, with a lateral pedicle mammaplasty, were reviewed. Using a standardised questionnaire, women reported on subjective changes in sensation after surgery, including time of recovery and the influence which surgery had on sensual function. Fifty-nine of these women were tested 3-7 years after surgery. Touch sensitivity was measured using a set of 20 Semmes-Weinstein monofilaments. Erectile function was also tested. The mean pressure threshold for the areola region was 19.12 g/mm(2) and for the nipple 16.75 g/mm(2), which is better that in studies on inferior pedicle mammaplasty. In previous studies patients were tested earlier, which may explain this difference.No correlation was found between sensitivity and resected tissue (for the areola p=0.88 and for the nipple p=0.82) or between sensitivity and age of patients (for the areola p=0.73 and for the nipple p=0.80). There were individual differences in the results. It is speculated that variability in anatomy of superficial nerves might explain these differences. Nearly all patients tested regained their erectile function. The majority of patients did not notice any change in their erogenous function. Twelve (12%) reported a post-surgical improvement of sensation. Nipples with partial loss of sensation persisted in 2% of the patients.

Small, novel proteins from the mistletoe Phoradendron tomentosum exhibit highly selective cytotoxicity to human breast cancer cells

Four novel proteins (phoratoxins C-F) have been isolated from the North American mistletoe Phoradendron tomentosum. The amino acid sequences of these phoratoxins were determined unambiguously using a combination of Edman degradation and trypsin enzymatic digestion, and by electrospray ionization tandem mass spectrometry sequencing. Phoratoxins C, E and F consist of 46 amino acid residues; and phoratoxin D of 41. All proteins had six cysteines, similar to the earlier described phoratoxins A and B, which are thionins. The cytotoxicity of each protein was evaluated in a human cell line panel that represented several cytotoxic drug-resistance mechanisms. For the half-maximal inhibitory concentrations (IC50 values) of the different cell lines in the panel, correlation with those of standard drugs was low. The most potent cytotoxic phoratoxin C was further tested on primary cultures of human tumor cells from patients. The solid tumor samples from breast cancer cells were 18 times more sensitive to phoratoxin C than the tested hematological tumor samples.

A novel multiparametric approach for analysis of cytoplasmic immunoglobulin light chains by flow cytometry

We describe a novel flow cytometric approach using a two-step acquisition technique to determine the cytoplasmic immunoglobulin light chains (LC) expression. Samples were prepared by a lysed-whole-blood technique and incubated with CD38-PE (phycoerythrin) and CD45-FITC (fluorescein isothiocyanate). The cells were fixed and acquired on an FACSCalibur flow cytometer (first acquisition). The cells were then permeabilized, incubated with either kappa-FITC or lambda-FITC and reacquired (second acquisition). Analysis of the data was performed by gating on the differing intensities of CD38 and evaluating them for the presence of a shifting FITC-positive population from the first acquisition to the second acquisition. The FITC fluorescence intensity of the second acquisition was equal to the sum of surface CD45 expression obtained during the first acquisition and the cytoplasmic LC expression obtained during the second acquisition. Thus, the shifting (increase) of FITC fluorescence intensity during the second acquisition is specifically due to the cytoplasmic expression of either the kappa or lambda LC. We studied 15 multiple myeloma (MM) patients and 10 controls (samples from patients without plasma cell dyscrasias). None of the controls showed evidence of any clonal populations. Thirteen of 15 MM patients exhibited clonal plasma cells (CD38 bright), ranging from 0.01% to 34% of total events collected. In addition, we identified another minute clonal population of lymphocytes (CD38 dim, CD45 bright, low forward and side scatter) in 12 of 13 MM patients with clonal plasma cells. This population, ranging from 0.01% to 0.6% of total events collected, had the same LC restriction as the clonal plasma cells. Patients with a ratio of minor clonal population to clonal plasma cells less than 0.07 tended to remain in partial or complete remission than those with a ratio > or =0.07 (4/5 versus 1/4, P <.1, chi(2)). We conclude that this method is highly sensitive and permits us to identify the minute clonal population of lymphocytes in MM patients. Our preliminary observations with a small cohort of patients imply that this minute clonal population may have important prognostic significance. The prognostic significance should be confirmed by further studies.

Cytotoxicity of digitoxin and related cardiac glycosides in human tumor cells

The saponin digitonin, the aglycone digitoxigenin and five cardiac glycosides were evaluated for cytotoxicity using primary cultures of tumor cells from patients and a human cell line panel (representing different cytotoxic drug-resistance patterns). Of these seven compounds, proscillaridin A was the most potent (IC(50): 6.4--76 nM), followed by digitoxin, and then ouabain, digoxin, lanatoside C, digitoxigenin and digitonin. Correlation analysis of the log IC(50) values for the cell lines in the panel showed that compound cytotoxicity was only slightly influenced by resistance mechanisms that involved P-glycoprotein, topoisomerase II, multidrug resistance-associated protein and glutathione-mediated drug resistance. Digitoxin and digoxin expressed selective toxicity against solid tumor cells from patients, while proscillaridin A expressed no selective toxicity against either solid or hematological tumor cells. The results revealed marked differences in cytotoxicity between the cardiac glycosides, both in potency and selectivity, and modes of action for cytotoxicity that differ from that of commonly used anticancer drugs.

Nodal staging of lymphoma with whole-body PET: comparison of

Accurate staging is elementary for optimal management of malignant lymphoma. Advanced cases may be curable with multidrug chemotherapy combined with radiotherapy, whereas limited disease can sometimes be cured by local radiotherapy only. Recently, FDG imaging with whole-body PET (WB PET) has been introduced as an accurate method for staging lymphoma. We evaluated the usefulness of L-[methyl-11C]methionine (MET) in comparison with FDG as a tracer for nodal staging of lymphoma with WB PET.

METHODS

Nineteen patients with untreated, histologically proven malignant lymphoma underwent WB PET imaging with MET and FDG within 1 wk before treatment. Fourteen patients had non-Hodgkin's lymphoma (NHL), and 5 had Hodgkin's disease (HD). Two of these 19 patients were excluded from the final analysis because of hyperglycemia. WB PET images using FDG and MET were visually compared by 3 independent interpreters, and the PET findings were correlated with the data on the basis of conventional staging studies.

RESULTS

Fifty-five of 178 lymph node regions were classified as diseased both by FDG PET and by CT, and 54 of 178 were classified as diseased both by MET PET and by CT. In addition, 11 lymph node regions that CT showed to be normal avidly accumulated FDG. Ten of these lymph node regions also had clear uptake of MET. Another 4 and 5 lymph node regions were enlarged at CT but were judged to be normal by FDG and MET PET, respectively. In nodal staging, both FDG PET and MET PET would have upstaged the disease in 3 patients. MET PET would also have downstaged the disease in 1 patient.

CONCLUSION

FDG and MET seem to be comparable in the detection of lymphoma by WB PET. However, visual interpretation of the images tends to be hampered more by physiologic accumulations of MET than by normal accumulations of FDG, and MET may be preferable to FDG in hyperglycemic patients undergoing staging studies with PET.

A novel human processed gene, DAD-R, maps to 12p12 and is expressed in several organs

A cDNA of a processed gene of human DAD-1 (defender against apoptotic cell death) was cloned from the human neuroblastoma cell line SH-SY5Y. The genomic sequence of this novel processed gene, DAD-R, lacked introns and was flanked by 8 bp terminal repeats. RT-PCR showed that the transcript is expressed predominantly in testis, ovaries, pancreas, lung and skeletal muscle. DAD-R has several possible initiation codons, one of them producing an open reading frame comprising 75% of the DAD-1 gene. We determined the chromosomal localization of DAD-R as 12p11.2-12p12.1, an area linked to familial synpolydactyly and frequently amplified in a variety of cancers, including those of testis, ovaries, pancreas and lungs.

Experience in qualitative and quantitative FDG PET in follow-up of patients with suspected recurrence from head and neck cancer

We evaluated positron emission tomography (PET) with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) in the detection of recurrent head and neck cancer, and compared visual and quantitative interpretation of PET images for their accuracy in the identification of tumour recurrence. Sixty-two FDG PET studies were performed in 56 patients having a total of 81 lesions, which were clinically suspected for recurrent carcinoma of the head and neck. The PET images were interpreted visually, and tracer uptake was quantitated as the standardised uptake value adjusted to body weight (SUV). Sensitivity of visual interpretation of the PET images for the presence of malignancy ranged from 84 to 95%, and specificity from 84 to 93%, respectively, depending on the selected scheme for grading of the lesions. Malignant lesions accumulated significantly more FDG than the benign ones (the median SUVs were 6.8 and 3.3, respectively, P<0.001). However, there was a wide overlap of the FDG uptake values between these two groups. Hence, the highest accuracy of quantitative analysis in correct identification of tumour recurrence (75% at Receiver Operating Curve analysis) was inferior to that of visual analysis (89%). FDG PET is feasible for the detection of recurrent head and neck cancer. Although quantitation of FDG uptake using SUV shows significantly higher tracer concentrations for malignant than benign lesions, the wide overlap of individual SUVs between these two groups is a serious concern in diagnostic evaluation. Therefore, in clinical practice it may be preferable to identify the presence of tumour recurrence within this patient group by qualitative interpretation of the PET images.

Glycosylation of phytepsin and expression of dad1, dad2 and ost1 during onset of cell death in germinating barley scutella

Dysfunction and downregulation of dad (defending against death) has been linked to programmed cell death (PCD) in animals and plants. As DAD is an essential subunit of the oligosaccharyltransferase that is located in the ER membrane, the results have raised the possibility that downregulation of N-linked glycosylation could be involved in the regulation of PCD. Here we show that the 16 kDa subunit of phytepsin, a vacuolar proteinase, is normally processed and glycosylated at the onset of DNA fragmentation in germinating barley scutella. Two cDNA clones encoding dad (dad1, dad2), and one cDNA encoding another subunit of the same oligosaccharyltransferase complex (ost1) were isolated from barley. Northern analysis of germinating scutella show that the expression of only dad1 is declining before onset of DNA fragmentation. In contrast to this, the expression of both dad2 and ost1 increase before onset of DNA fragmentation.

Epidemiology of unintentional drowning and near-drowning in Denmark in 1995

OBJECTIVES

To determine the pattern of accidental drowning and near-drowning in Denmark.

DESIGN

Prospective study of all cases of accidental drowning and near-drowning during one year.

SETTING

Denmark, 1995.

SUBJECTS

All patients brought to Danish hospitals after incidents of unintentional near-drowning or cooling in water and all fatal cases.

MAIN OUTCOME MEASURES

Number of near-drowned patients reported prospectively by hospital departments supplemented by cases reported after requests based on the National Patient Register. Number of drownings reported by public health medical officers (as medical examiners), institutes of forensic medicine, and hospitals.

RESULTS

Sixty three (38%) of 167 unintentionally immersed persons died: eight (17%) of 47 children and 55 (46%) of 120 adults. The annual incidence of serious immersion events in children leading to hospital contact was 5.2/100,000; mortality was 0.7/100,000. For adult males the annual incidence of serious unintentional immersions was 4.3/100,000 and for females 1.2/100,000. For foreigners the risk was three to four times higher than for Danes.

CONCLUSIONS

More attention should be paid to the risk of drowning in children, adult males, and foreigners.

NOX 100, a nitric oxide scavenger, enhances cardiac allograft survival and promotes long-term graft acceptance

BACKGROUND

We examined the role of nitrosative stress in allograft destruction.

METHODS

Rats undergoing cardiac transplants received NOX-100, a water-soluble nitric oxide (NO) scavenger with antioxidant properties, with or without low-dose cyclosporine (CsA). Graft survival, NO production, and nuclear factor kappa B (NF-kappaB) activity were studied.

RESULT

Using NOX-100 daily until rejection prolonged graft survival (11.6+/-0.6 vs. 7.4+/-0.2 days; P<0.05). Daily low-dose CsA (2.5 mg/kg im) for 7 days or until rejection also prolonged survival (12.6+/-0.5 and 21.6+/-1.6 days, respectively; P<0.01 vs. Controls). Low-dose CsA for 7 days and NOX-100 for 30 days prolonged graft survival (45.0+/-4.7 days; P<0.01 vs. all groups.). NOX-100 had no effect on whole blood CsA levels. Combination therapy until Day 100 resulted in 1 graft loss at Day 116 and indefinite survival in 3 animals (>300 days), which accepted a second WF strain heart without further immunosuppressive therapy but promptly rejected a third party (ACI) cardiac allograft. NOX-100 and CsA reduced nitrate and nitrite, and combination therapy completely normalized NO through to Day 30. Electron paramagnetic resonance spectroscopic analysis demonstrated reduction of signals for nitrosylmyoglobin and nitrosyl-heme with NOX-100 and elimination of signals with CsA alone or combination therapy. Activity of myocardial NF-kappaB decreased with monotherapy vs. untreated allografts. Combination therapy resulted in further inhibition of NF-kappaB up to Day 30. The extent of graft survival correlated with the extent of NO scavenging and NF-kappaB inhibition. Short-term combination therapy had no effect on graft lymphocytic infiltrate on Days 15, 20, and 30.

CONCLUSION

These data support a role for both oxidative and nitrosative stress in rejection and the immunoregulatory potential of antioxidant therapy after transplantation.

Oxygen-conserving effects of apnea in exercising men

We sought to determine whether apnea-induced cardiovascular responses resulted in a biologically significant temporary O(2) conservation during exercise. Nine healthy men performing steady-state leg exercise carried out repeated apnea (A) and rebreathing (R) maneuvers starting with residual volume +3.5 liters of air. Heart rate (HR), mean arterial pressure (MAP), and arterial O(2) saturation (Sa(O(2)); pulse oximetry) were recorded continuously. Responses (DeltaHR, DeltaMAP) were determined as differences between HR and MAP at baseline before the maneuver and the average of values recorded between 25 and 30 s into each maneuver. The rate of O(2) desaturation (DeltaSa(O(2))/Deltat) was determined during the same time interval. During apnea, DeltaSaO(2)/Deltat had a significant negative correlation to the amplitudes of DeltaHR and DeltaMAP (r(2) = 0.88, P < 0.001); i.e., individuals with the most prominent cardiovascular responses had the slowest DeltaSa(O(2))/Deltat. DeltaHR and DeltaMAP were much larger during A (-44 +/- 8 beats/min, +49 +/- 4 mmHg, respectively) than during R maneuver (+3 +/- 3 beats/min, +30 +/- 5 mmHg, respectively). DeltaSa(O(2))/Deltat during A and R maneuvers was -1.1 +/- 0.1 and -2.2 +/- 0.2% units/s, respectively, and nadir Sa(O(2)) values were 58 +/- 4 and 42 +/- 3% units, respectively. We conclude that bradycardia and hypertension during apnea are associated with a significant temporary O(2) conservation and that respiratory arrest, rather than the associated hypoxia, is essential for these responses.

Clinical correlations of genetic changes by comparative genomic hybridization in Ewing sarcoma and related tumors

Our previous comparative genomic hybridization (CGH) study of Ewing sarcoma and related tumors showed that DNA sequence copy number increases of 1q21-q22 and of chromosomes 8 and 12 were associated with trends toward poor survival (Armengol et al., Br J Cancer 1997, 75, 1403-1409). These trends were not statistically significant. In the present study, we analyzed 28 primary Ewing sarcomas and related tumors by CGH to study whether these (or other) changes have prognostic value in these tumors. Twenty-one tumors (75%) had changes with a mean of 1.9 changes per tumor. The most frequent aberration was gain of chromosome 8 in 10 tumors (36%). Five tumors (18%) had copy number increases at 1q21-22 and 5 had gain of 7q. Copy number increase of 6p21.1-pter, gain of chromosome 12, and loss of 16q were seen in 11%. Copy number increases of 1q21-q22 and of chromosomes 8 and 12 were associated with trends toward worse outcome, but the differences did not reach statistical significance. A novel finding is the association of copy number increase at 6p with worse distant disease-free (P = 0.04) and overall survival (P = 0.004). To confirm this finding and to see whether copy number increases of 1q21-q22 and of chromosomes 8 and 12 have definite prognostic value, a larger number of cases needs to be studied.

Factors predicting atracurium reversal time

BACKGROUND

To identify individual factors and combination of factors predictive of reversal time (defined as time from neostigmine administration to train-of-four (TOF) ratio 0.70) from atracurium-induced neuromuscular block, the present study tested the following variables as possible predictors of reversal time: 1) degree of block at the time of antagonism as quantified by first response to TOF or double-burst stimulation (DBS); 2) time from last supplemental dose of atracurium to administration of neostigmine (pre-reversal time); and 3) time from administration of initial atracurium dose to T1 (the magnitude of the first twitch in TOF) recovered to 10% (duration of action of the initial dose of atracurium).

METHODS

The study population comprised 83 female patients, ASA physical status 1 or 2, anaesthetized with fentanyl, thiopental, halothane and nitrous oxide. Initial and supplemental doses of atracurium were 0.5 mg x kg(-1) and 0.15 mg x kg(-1), respectively. Evoked responses to TOF or DBS were recorded mechanomyographically. Neuromuscular block was antagonized with neostigmine, 0.07 mg x kg(-1), at varying time intervals (6-50 min) after the final atracurium dose.

RESULTS

Multiple linear regression analyses testing T1, D1 (the magnitude of the first twitch in DBS), pre-reversal time and duration of action of the initial dose of atracurium, demonstrated that with superficial block, T1 >15%, T1 is the only significant predictor for reversal time. With moderate block, 0< T1 < or =15%, both T1 and duration of action of the initial atracurium dose are significant predictors for reversal time. With profound block, T1=0, duration of action of the initial dose and pre-reversal time are significant predictors for reversal time.

CONCLUSION

1) T1 is a more important predictor for reversal time from atracurium-induced neuromuscular block than D1; 2) predictors differ with the degree of block: with T1 > 15%, T1 is the only significant predictor; with 0< T1 < or =15%, the duration of action of the initial dose and T1 are predictors for reversal time; with T1=0, the duration of action of the initial dose and pre-reversal time predict reversal time.

Evaluation of early response to radiotherapy in head and neck cancer measured with [11C]methionine-positron emission tomography

PURPOSE

To evaluate whether positron emission tomography (PET) with carbon-11-methionine (MET) can be used for detection of early response to external beam radiotherapy (RT) in untreated head and neck cancer using locoregional control and survival as study endpoints.

MATERIALS

Fifteen patients with head and neck cancer underwent a MET PET study before RT and after a median dose of 24 Gy. Fractionation was standard (n = 6) or hyperfractionated (n = 9), and 13 out of 15 patients had planned surgery after RT. SUV was calculated for primary tumor (n = 13) or largest lymph node metastasis in two patients of whom one had his primary excised before study enrollment and one presented with unknown primary tumor syndrome.

METHODS

Attenuation corrected PET scans acquired 20-40 min from tracer injection were used for evaluation of MET uptake in tumors. A quantitative MET uptake index was expressed as standardized uptake value (SUV) or SUV(lean) (corrected for lean body mass). The PET results were correlated with clinical follow-up data. The median follow-up time is currently 28 months (range 22-34).

RESULTS

A total of 13 primary tumors and 12 metastatic lymph nodes were visually identified in MET PET. In the first PET study the median SUV in tumor was 8.6 (range, 5.5-14.0). In the second PET study performed during RT the median SUV decreased to 5.7 (range, 3.1-8.2, P = 0.001). Two out of 15 patients showed no radiation-induced decrease in SUV. The median tumor SUV ratio of patients remaining in local control (CR) after RT was 0.7 (range 0.6-0.8, n = 6), and that of relapsing patients similarly 0.7 (range 0.5-1.0, n = 9, NS). The SUV ratio was not associated with survival time. The MET uptake of submandibular salivary glands decreased in all patients during the first two or three weeks of RT (P = 0.03).

CONCLUSIONS

MET uptake in tumor shows a significant decrease during the first two to three weeks of RT of head and neck cancer. It appears that the rate of decrease in tracer uptake is comparable in relapsing patients and those who remain locally controlled and thus the use of MET PET for prediction of response to RT is limited.

[Do flame retardants increase the risk of non-Hodgkin lymphoma? The levels of polybrominated diphenyl ethers are increasing in the environment]

Adipose tissue levels of tetra-BDE (2,2',4,4' tetra-brominated diphenyl ether) were measured in 42 male or female cancer patients [19 with non-Hodgkin's lymphoma (NHL), 23 with malignant melanoma (MM)], and in 27 controls without a diagnosis of cancer. As compared with tetra-BDE concentrations in controls, those in the MM subgroup did not differ, but those in the NHL subgroup were higher. Subgrouping of the cancer patients by occupational categories showed professional car, bus and truck drivers (at possible risk of exposure to PBDEs used as flame retardants in vehicle manufacture) to have higher tetra-BDE levels than controls, but not computer operators (at possible risk of exposure to PBDEs used in VDUs). Due to the small size of the series, however, the results may solely be regarded as hypothesis-generating, and further studies are needed.

[PET-findings in head-and neck cancers]

Head and neck cancer is very suitable for investigation with PET (positron emission tomography), usually owing to the locoregional spread at the time of diagnosis. Thus, the data collected enable any lesions present to be visualised. Evaluation of tumour metabolism with PET may simplify the diagnosis of metastases, and be of predictive value, enabling response to radiotherapy and cytostatic therapy to be predicted. It serves as a complement to CT (computed tomography) and MRI (magnetic resonance imaging) in the diagnosis of recurrence, and is thus useful in planning surgical intervention. Methods capable of distinguishing hypoxic or rapidly dividing cells can be useful in the choice of effective treatment methods such as hyperfractionated radiotherapy, drugs which enhance radiosensitivity, the degree of radical surgery, and the use of gene therapy.

Myocardial nuclear factor-kappaB activity and nitric oxide production in rejecting cardiac allografts

BACKGROUND

Nuclear factor-kappaB (NF-kappaB) is a rapid response transcription factor for genes whose products are critical for inflammation and immunity. In a rat model of heterotopic cardiac transplantation, we studied NF-kappaB DNA binding activity and nitric oxide (.NO) production in untreated allografts and whether inhibition of NF-kappaB suppresses .NO production and prolongs graft survival.

METHODS

In allograft recipients and isograft controls, NF-kappaB was assayed by electrophoretic mobility shift assay, daily from transplant until rejection. Myocardial .NO was directly detected in explanted allografts by electron spin resonance spectroscopy on day 6 after transplant. The potent inhibitor of NF-kappaB, pyrrolidine dithiocarbamate (PDTC; 250 mg/kg s.c.) was administered daily from transplant until day of rejection. The extent of graft lymphocytic infiltrate was assessed by routine hematoxylin and eosin staining. Immunohistochemical staining of NF-kappaB was per formed to identify the cell type responsible for NF-kappaB activity.

RESULTS

A time-dependent increase in myocardial NF-kappaB activity was seen in untreated allografts as compared with isografts as determined by PhosphorImage analysis. Peak NF-kappaB activity occurred in allografts on day 4 with a ninefold increase as compared with isografts (24.0+/-3.7% vs. 2.7+/-0.5; P<0.05). On posttransplant day 6, electron spin resonance spectroscopy analysis of allografts demonstrated .NO identified by a triplet nitrogen signal centered at g=2.012 with hyperfine splitting of 17.5 Gauss, which is consistent with nitrosoheme formation and low-field signals at g=2.08 and g=2.03 consistent with nitrosomyoglobin. These signals were not seen in native hearts of allograft recipients. With PDTC administration, a threefold decrease in NF-kappaB activity within the transplanted heart was observed on posttransplant day 5 as compared with untreated allografts (9.7+/-1.6% vs. 23.5+/-2.5%; P<0.01). PDTC prolonged graft survival as compared with untreated allografts (11.7+/-0.3 vs. 6.6+/-0.2 days; P<0.05) and reduced the intensity of the nitrosoheme and nitrosomyoglobin signals. Allograft mononuclear cell infiltrate correlated with peak NF-kappaB activity with peak infiltrate on posttransplant day 4. PDTC treatment had no effect on the extent of infiltrate. Immunohistochemical staining localized NF-kappaB to the infiltrating mononuclear cells on posttransplant day 5.

CONCLUSION

These data support a role for NF-kappaB in allograft rejection.

Carbon-11-methionine uptake in squamous cell head and neck cancer

The purpose of this study was to investigate whether uptake of L-methyl-[11C]-methionine in a tumor is related to the survival of patients with squamous cell cancer of the head and neck.

METHODS

Thirty-nine patients (median age 64 yr) with newly diagnosed squamous cell carcinoma of the head and neck entered a PET study with [11C]-methionine before therapy. Tumor [11C]-methionine uptake was measured as standardized uptake values (SUVs), and the PET results were compared with the clinical follow-up data of the patients.

RESULTS

All except one of the malignant lesions within the field of view were visible by [11C]-methionine PET. The median tumor SUV was 9.0 (range 4.0-18.8). The median follow-up time for patients still alive is currently 44 mo (range 14-66 mo). No difference in survival was found between patients with tumor SUV equal to or larger than the median and those with tumor SUV smaller than the median.

CONCLUSION

Carbon-11-methionine PET imaging is effective in squamous cell head and neck cancer. The amount of [11C]-methionine uptake does not predict the clinical outcome.

Use of carbon-11 methionine positron emission tomography to assess malignancy grade and predict survival in patients with lymphomas

The aim of this study was to investigate whether uptake of carbon-11 methionine (MET) is associated with histological grade of malignancy and survival in patients with newly diagnosed or recurrent lymphoma. Thirty-two patients with histologically confirmed lymphoma participated in the study. Twenty-six (81%) were studied before any therapy and six before treatment for recurrent disease. Twenty-eight patients had non-Hodgkin's lymphoma and four had Hodgkin's disease. An ECAT 931/08-12 positron emission tomography (PET) scanner was used for PET imaging. After the transmission scan, a median dose of 293 MBq of MET was injected intravenously and dynamic images were acquired for 40 min. The uptake of MET in tumour was measured as the standardized uptake value (SUV) and influx constant (Ki). The SUV formula was also adjusted to the predicted value of lean body mass (SUVlean) and body surface area (SUVBSA). The PET results were correlated with the clinical follow-up data. The median SUV in 32 malignant lesions was 6.6 (range, 1.9-12.4) and the median Ki was 0. 116 min-1 (range, 0.025-0.201, n=23). The median SUV was 7.0 (range, 5.4-12.4, n=9) in high, 6.2 (range, 1.9-10.4, n=11) in intermediate and 5.7 (range, 3.8-8.3, n=8) in low grade lymphomas. One intermediate grade lymphoma of the skin was visually negative (SUV 1. 9). In Hodgkin's disease the median SUV was 7.0 (range, 3.2-7.9, n=4). The median Ki value was 0.162 min-1 (range, 0.147-0.197, n=7) in high, 0.099 (range, 0.025-0.152, n=10) in intermediate, and 0.078 (range, 0.056-0.152, n=4) in low grade lymphomas and 0.149 (range, 0. 096-0.201, n=2) in Hodgkin's disease. The difference between high and other grade non-Hodgkin's lymphomas was significant when using Ki (P<0.001), but not with SUV, SUVlean or SUVBSA. The final outcome of the patients was not related to MET uptake. Lymphomas with a high Ki value tended to have a high S-phase fraction (r2=0.46, P=0.043). It is concluded that MET PET is highly sensitive for the detection of untreated and recurrent lymphomas. Differentation of high grade lymphomas from lower malignancy grades seems to be possible if graphical analysis is applied to calculate Ki for MET. However, prediction of survival is not possible with MET PET.

Antagonism of atracurium-induced block in obese patients

PURPOSE

To investigate the relationship between total body weight (TBW) or body mass index (BMI) and atracurium reversal time.

METHODS

The study population comprised 25 patients with TBW < 80 kg and 25 patients with TBW > or = 80 kg anaesthetised with midazolam, thiopentone, fentanyl, nitrous oxide and halothane. Neuromuscular block was induced with 0.5 mg.kg-1 atracurium and maintained with doses of 0.15 mg.kg-1. Neuromuscular transmission was recorded using train-of-four (TOF) nerve stimulation and mechanomyography. Neostigmine, 0.07 mg.kg-1, was administered when the first twitch in TOF had recovered to 10% of control. Reversal time was defined as: time from administration of neostigmine until TOF ratio recovered to 0.70.

RESULTS

There was no difference in reversal time between patients with TBW < 80 kg (7.2 +/- 2.6 min, mean +/- SD), and patients with TBW > or = 80 kg (6.9 +/- 3.6 min). When patients were grouped according to BMI there was no difference in reversal time between groups with low BMI (6.9 +/- 2.6 min) or high BMI (7.1 +/- 3.6 min). There was, furthermore, no difference in reversal time between the 15 patients in the study population with the smallest TBW or BMI and the 15 patients with the greatest TBW or BMI. There was no correlation between TBW or BMI and reversal time.

CONCLUSION

When atracurium-induced neuromuscular block is antagonised with 0.07 mg.kg-1 neostigmine. TBW or BMI have no influence on reversal time.

New equipment for neuromuscular transmission monitoring: a comparison of the TOF-Guard with the Myograph 2000

OBJECTIVE

The present study is to clarify whether the bias and limits of agreement of the TOF-Guard and the mechanomyograph differ from those of two mechanomyographs on contra lateral arms. Previous studies of the bias and limits of agreement between acceleromyographical (TOF-Guard) and mechanomyographical measurements of neuromuscular transmission did not take the error introduced by using contra lateral arms into consideration.

METHODS

Fifty-two women undergoing gynecological surgery were anesthetized with midazolam, fentanyl, thiopental, halothane and nitrous oxide. Neuromuscular blockade was induced and maintained with atracurium. In 32 patients, neuromuscular monitoring was performed with a Myograph 2000 on one hand and a TOF-Guard at the other (M/T group). In 20 patients, monitoring was performed with a Myograph 2000 at both hands (M/M group). Train-of-four stimulations were applied to the ulnar nerve at the wrist in both groups. Bias and limits of agreement between the contra lateral hands in each group were calculated as proposed by Bland and Altman.

RESULTS

When the TOF ratio was 0.25, TOF ratio bias and limits of agreement in the M/T group were 0.86 and 17.58 to -15.85, respectively. Corresponding values in the M/M group were -1.75 and 12.3 to -8.8. Bias in the M/T group decreased significantly to -8.1 when TOF ratio increased to 0.70, resulting in limits of agreement of 12.1 to -28.4. The corresponding values in the M/M group were bias 2.0 and limits of agreement 10.7 to -6.7. TOF-Guard bias for onset time and time to 5% recovery of T1 (first twitch in TOF) were -19s and -1.5 min, respectively; both values differed significantly from zero (P < 0.05). Taken together with the changing TOF-ratio bias during recovery in the M/T group, these results indicate different onset and recovery curves for the two monitoring devices.

CONCLUSIONS

Due to wide limits of agreement and different recovery courses, acccleromyographic and mechanomyographic recordings of neuromuscular transmission cannot be used interchangeably. The substantial variation between simultaneous mechanomyographical recordings of neuromuscular transmission obtained in contra lateral arms suggests that this factor should be taken into account when studying new neuromuscular monitoring techniques using the two-arm technique.