First Direct Measurement of ^{22}Mg(α,p)^{25}Al and Implications for X-Ray Burst Model-Observation Comparisons

Type-I x-ray bursts can reveal the properties of an accreting neutron star system when compared with astrophysics model calculations. However, model results are sensitive to a handful of uncertain nuclear reaction rates, such as ^{22}Mg(α,p). We report the first direct measurement of ^{22}Mg(α,p), performed with the Active Target Time Projection Chamber. The corresponding astrophysical reaction rate is orders of magnitude larger than determined from a previous indirect measurement in a broad temperature range. Our new measurement suggests a less-compact neutron star in the source GS1826-24.

[Sexual dysfunctions after traumatic brain injury: Systematic review of the literature]

BACKGROUND

Sexual dysfunction (SD) is common in the general population, up to 50% in women and with no clearly defined prevalence in men but up to 30% in erectile dysfunction. Sexual dysfunctions (SD) are common after a traumatic brain injury (TBI) but remain underrated in clinical practice, yet it is a crucial aspect of the person with consequences for the relationship with the other, psychological wellbeing and quality of life.

OBJECTIVE

To determine, through a systematic literature review, the epidemiology, assessment tools and treatment of SD in the TBI population.

SOURCES

(keywords, languages): Medline, COCHRANE and OVID databases were used with specific keywords (MeSH), combined with Boolean operators: "sexual dysfunction", "sexuality", "erectile dysfunction" and "traumatic brain injury".

STUDY SELECTION

Only studies published in French or English, and with full-text available, have been included. Articles have been independently reviewed and extracted.

RESULTS

Of the 199 articles reviewed after exclusion of duplicates, 86 articles were reviewed in their full text. A total of 40 studies were included in the final analysis. After TBI, 6% to 83% of patients report SD: decreased frequency of sexual intercourse (47-62%), desire and/or arousal (24-86%), erectile dysfunction (24,2-57%), difficulties with orgasm (29-40%), inappropriate sexual behaviour (8,9%). There is no consensus method for evaluating SD in this population, with 16 tools identified. Among them, only two questionnaires were validated in this population, the Brain Injury Questionnary of Sexuality - not validated in French - and the Overt Behavior Scale, the latter being intended for the evaluation of sexual behaviour disorders. Several factors are significantly and positively associated with SD: age (P≤0.01), severity of TBI (P≤0.002), depression (P<0.001), anxiety (P<0.001), and fatigue (P=0.042). Others are negatively associated: time since injury (P=0.01), perceived physical health status (P<0.001) and social participation (P<0.001). There is little data on the treatment of SD outside of case studies.

LIMITS

Quantitative analysis could not be performed due to differences in the studies included in their design, evaluation tools, choice of TBI severity criteria, and post-TBI timeframes. Four unavailable articles could not be consulted.

CONCLUSION

SD are common after TBI but remain poorly evaluated in clinical practice, despite their impact on patients and their partners. Their evaluation and treatment should be part of the overall management of patients after TBI. Nevertheless, there is currently no validated tool in French to evaluate these SD, nor are there any guidelines on their treatment.

Ambulatory unicompartmental knee arthroplasty: Short outcome of 50 first cases

INTRODUCTION

The reduction in length of stay (LOS) in orthopedic surgery has been steady for several years. For the past 3 or 4 years in France, the trend toward outpatient surgery has been growing upwards, as it is a goal for hospital administration.

MATERIALS AND METHODS

This is a prospective, continuous, mono-centric, single operator study on 56 UKAs. Included were all UKAs carried out between January 2014 and December 2015, meeting the following criteria: voluntary patients, supportive family environment, absence of comorbidity (oral anticoagulants, diabetes, obesity), ASA score≤3. Preoperatively, patients received: Dexamethasone 2mg/10kg, Tranexamic acid 2g, Cefazolin 2g IV. All patients were operated on under general anesthesia with the same technique: Alpina^® (Zimmer-Biomet) uni-prosthesis without tourniquet. The arthrotomy was closed after a capsular injection of a solution of 150mg Ropivacaine+30mg Bi-Profenid^®. Patient discharge on the same day evening was authorized by both surgeon and anesthesiologist. Three criteria were quantified: number of patients seen before the date of the first consultation for the removal of stitches (around day 12), Visual Pain Scale (10 points scale) on the first 12 days, and the level of satisfaction at the one-month postoperative visit.

RESULTS

Six patients (11%) were not included in the ambulatory program during the initial consultation. Three patients were not able to be discharged on the same day evening due to nausea and therefore remained hospitalized for one night. Eighteen patients (38%) were reviewed before D10: 13 patients were reviewed between D1 and D4 for bleeding through the dressing and 5 for pain not controlled by level 1 and 2 analgesics. The Visual Pain Scale (VPS) reached level 6±2 by the 2nd day and then dropped to 1±1 by the 12th day. At 1 month, 85% of the patients were satisfied or very satisfied with their care. There were no general or localized complications.

DISCUSSION

Ambulatory UKA surgery is possible for most patients. The inclusion rate for ambulatory UKA was 88% for Berger RA in 2010, therefore very close to this study rate of 89%. Ambulatory care is not only a change in surgical and anesthetic practice but a totally new management process involving all medical and non-medical actors. Ambulatory UKA surgery is feasible and safe for most patients.

LEVEL OF EVIDENCE

IV, retrospective cohort study.

Fast ρ-NQR Imaging with Slice Selection

A combination of a new pulse sequence allowing fast data acquisition in the rotating frame version of NQR (ρ-NQRI) together with a method for slice selection, is reported. The procedure allows us to record the magnetization evolution during its motion in the rotating frame. At the same time a zero-crossing external magnetic field gradient is applied in order to select a determined slice of the object to be imaged. The experiments reported are the first steps toward a fast tridimensional ρ-NQRI; even more, as the spectroscopic information is preserved during the spatial encoding procedure, it could be considered as a 3D spatially resolved NQR spectroscopy technique.

On the Reconstruction of NQR Nutation Spectra in Solids with Powder Geometry

In single crystals the NQR nutation frequency depends on the relative orientation of the coil and the quadrupole axes. In powders the nutation lineshape is a superposition of spectra from the randomly oriented single crystals, so that powder patterns appear in such experiments if the recon­struction is performed by the Fourier transform method. In this paper an alternative reconstruction method of nutation spectra is suggested making use of the Hankel Transform. In this way the nutation spectra are simplified. Singularities arising with experiments for the determination of the asymmetry parameter η can easily be resolved. In the particular case of an axially symmetric quadrupolar tensor and a homogeneous radiofrequency field one can reduce the powder pattern to a single line without heterogeneous broadening with respect to orientation. Further improvement o f the nutation spectra can be achieved by taking advantage of the maximum entropy method, which strongly reduces apodisation and noise problems. Applications of the new data manipulation techniques to N Q R imaging methods published elsewhere and 2D zero-field N Q R spectroscopy are reported.

Reduction plasty for hypertrophic anterior cruciate ligament mucoid degeneration: clinical and knee laxity outcomes in 23 cases

INTRODUCTION

The best treatment for anterior cruciate ligament (ACL) mucoid degeneration remains open to debate. Current options are total or partial ACL resection, or a more conservative strategy, reduction plasty. The goal of this study was to retrospectively evaluate the effects of reduction plasty for ACL hypertrophy due to mucoid degeneration from clinical outcome and knee laxity points of view.

MATERIALS AND METHODS

Arthroscopy was carried out on 23 knees (21 patients) to perform a circular volume reduction plasty of the ACL, while preserving the greatest number of ligament fibers. Notchplasty was not performed. All the patients were seen again with an average follow-up of 32 months (range 8-70).

RESULTS

All the knees except three had symmetric postoperative flexion. Three patients still had pain. No patient reported having subjective feelings of instability. Among the 20 knees tested with the GNRB(TM) knee laxity measurement device, one knee had a 2.4mm difference in laxity and three had between 3 and 4mm of difference; 16 knees had no residual laxity.

DISCUSSION

Treatment of ACL mucoid degeneration by reduction plasty leads to complete pain relief in 80% of cases while maintaining good postoperative knee stability.

LEVEL OF EVIDENCE

Level IV. Retrospective study.

Medial unicompartmental knee arthroplasty: does tibial component position influence clinical outcomes and arthroplasty survival?

INTRODUCTION

In several recent studies, unicompartmental knee arthroplasty (UKA) produced better functional outcomes than did total knee arthroplasty with 10-year prosthesis survival rates greater than 95%. Nevertheless, UKA is still widely viewed as producing inconsistent results. Tibial component loosening is the leading cause of failure. We consequently sought to identify tibial component position criteria associated with outcomes of medial UKA.

MATERIAL AND METHODS

We conducted a retrospective multicentre study of 559 medial UKAs performed between 1988 and 2010 in 421 patients (262 females and 159 males) with a mean age of 69.51±8.72 years at surgery. We recorded the following radiographic parameters: joint space height, obliquity and slope of the tibial implant, whether the tibial component was perpendicular to the femoral component, and lower limb malalignment. The International Knee Society (IKS) score was used to assess clinical outcomes. Mean follow-up at re-evaluation was 5.17±4.33 years.

RESULTS

The mean 10-year prosthesis survival rate was 83.7±3.5%. Factors associated with decreased prosthesis survival were a greater than 2-mm change in joint space height, a greater than 3° change in tibial component obliquity, a slope value greater than 5° or a change in slope greater than 2°, and more than 6° of divergence between the tibial and femoral components. Residual mechanical varus of 5° or more was also associated with mechanical failure. The only factor associated with worse functional score values was joint space elevation by more than 2mm.

DISCUSSION

The high level of accuracy required for optimal positioning of the tibial component during medial UKA indicates a need for considerable technical expertise and emphasises the conservative nature of the procedure. Optimal positioning is crucial to restore normal knee kinematics and to prevent implant wear and lesions to adjacent compartments.

LEVEL OF EVIDENCE

IV, retrospective study.

A new knee arthrometer, the GNRB: experience in ACL complete and partial tears

INTRODUCTION

Clinical diagnosis of anterior cruciate ligament (ACL) tears (Lachman test and Pivot shift test in valgus and internal rotation) is reliable in case of complete ACL tear but reveals elusive in case of partial tears. Quantitative assessment of anterior tibial translation proves to be imprecise, subjective and poorly reproducible especially with the KT-1000 arthrometer. We developed the GNRB, an alternative original anterior knee laxity measurement device. The lower limb is placed in a rigid support with the knee at 0 degrees of rotation, the restraining power being recorded. A 0-250 N thrust force is transmitted by a jack to the upper segment of the calf. This force is only applied in the absence of hamstring muscles contraction. Displacement of the anterior tibial tubercle is recorded using a sensor with a 0.1mm precision.

HYPOTHESIS

We hypothesize that this knee laxity measurement device is more reliable and reproducible than other currently available arthrometers.

MATERIAL AND METHODS

During a first validation study, the GNRB was compared to the KT-1000 arthrometer, in 20 pairs of healthy knees, measurements being performed by two investigators. Variance analyses were carried out at 134 N. In a second clinical study, 21 complete ACL tears (the notch is devoid of ACL) and 24 partial ACL tears (anterior or posterior bundle tear and cicatricial ACL remnant in continuity) were tested with these arthrometers to exact a differential laxity threshold value between both knees at 250 N. Statistical analysis was subsequently performed using variance and ROC curves analysis.

RESULTS

The GNRB arthrometer reveals to be significantly more reproducible than the KT-1000, irrespectively of the tester's experience level. Moreover, unlike the KT-1000, the achieved measurement is independent from the uninvolved side. Reproducibility of laximetry proves to be significantly better with the GNRB than with the KT-1000, wherever the examiner's experience stands and whatever the evaluated side condition could be. When differential laxity threshold value was 3mm in complete ACL tears, sensitivity was 70% and specificity 99% at 134 N. Using a 1.5mm threshold value in ACL partial tears, the arthrometer sensitivity was 80% and specificity was 87% at 134 N.

DISCUSSION

Reproducibility of laximetry was significantly better with the GNRB than the KT-1000 device, wherever the examiner's experience stands and whatever the evaluated side-condition could be. The GNRB reports various supplementary advantages compared with other available laximeters. Good control of the investigated limb position in rotation, recording of translation in the absence of hamstring muscles contraction and in direct comparison with the KT-1000: reproducibility, constant pressure, arthrometry improved accuracy and automated measurements recording. The GNRB might be used for diagnosis of partial and complete ACL tears and during follow-up of reconstructed or not ACL tears.

LEVEL OF EVIDENCE

type II. Prospective comparative study.

[Computer assisted orthopedics surgery]

Computer-assisted surgery has become commonplace in orthopedic surgery. The number of applications grows steadily as does the number of patients benefiting from these new techniques. The hearty debates heard when these techniques were first introduced have now given way to more evidence-based evaluation. Our objective here is to continue this approach by presenting our six-year experience with navigation. We will not discuss the theoretical background of these technologies nor attempt to present an exhaustive review of the literature but rather focus attention on surgical skills acquired by a group of surgeons working in a wide range of areas. The common point is that all have now integrated computer-assisted navigation into their routine surgical practices including: a) first-intention and revision knee arthroplasty; b) hip arthroplasty; c) anterior cruciate ligament surgery; d) proximal tibial osteotomy; e) shoulder arthroplasty. We will terminate this round table with a presentation of future technological advances and propose our advice for an increasingly widespread use of these new techniques.

[What's new in fundamental research: cartilage]

The localized defects of the articular cartilage of the knee are not rare, in particular concerning the femoral condyles. There is practically no potential for spontaneous repair of cartilage defects reaching the sub-chondral bone and any destruction of the articular cartilage, independently of its origin, is final. This destruction has significant consequences. Currently used techniques, such as Pridie perforation or mosaicplasty have demonstrated effectiveness, but also their limitations. Implantation of autologous chondrocytes constitutes the main alternative to current therapeutic approaches. Nevertheless, many problem persist and have led to research and development of a validated technique for autologous chondrocyte implantation using a biomaterial support. Chondrocyte transplantation on solid support is currently under study.

[Osteochondritis dissecans of the femoral condyles: report of 892 cases]

PURPOSE OF THE STUDY

Osteochondritis rarely involves the femoral condyles. Discovery in this localization raises several questions concerning the nature of the articular cartilage, the potential for spontaneous healing, and, in the event of a free fragment, the outcome after its loss or repair.

MATERIAL AND METHODS

This multicentric study included 892 pediatric and adult cases, the cutoff between two series being defined by fusion of the inferior growth plate. We excluded medical or surgical osteochondritis, cases involving the patella, osteochondral fractures, juvenile polyosteochondrosis, adult osteonecrosis, and osteochondritis beginning after the age of 50 years.

RESULTS

Mean age at diagnosis was 16.5 years. Mean age at treatment onset was 22 years. Pain was the predominant symptom. 80% of cases were unilateral and 70% involved the medial condyle. The anatomic lesions were different in adults, showing more advanced degradation. At diagnosis, Bedouelle stages Ia and IIb constituted 80% of the cases observed among children while in adults, 66% were Bedouelle stages IIb to IV. Outcome was very good for the majority of children with Hughston clinical stage 4 while half of the x-rays were Hughston stage 3 and 4. There were thus a large percentage of children with abnormal xrays whose disease history was not yet terminated. In the adult series, the percentages of Hughston 3 and 4 was about the same as clinically. The x-rays were rarely perfectly normal since half of the clinical stage 3 patients were noted in stage 4. An abnormal x-ray with a very good clinical presentation was observed in a very large proportion of patients.

DISCUSSION

It is difficult to interpret the plain x-ray and identify patients with a potentially unfavorable prognosis. We defined three radiographic classes: defect, nodule and empty notch. The Bedouelle classification uses information from all available explorations, particularly MRI and arthroscopy. Numerous therapeutic methods are used. Interruption of sports activities is the first intention treatment for children. Data in the literature and the findings of this symposium do not demonstrate any beneficial effect of immobilization on healing compared with simple abstention from sports activities. Transchondral perforation is a simple operation with low morbidity. In 85% of cases, it was used for lesions with an intact joint cartilage considered stable in 96% of cases. Healing was achieved in six months for 48% if the growth plate had not fused. The fragment was fixed in 43% of the cases with a loose cartilage fragment. Outcome was fair but degraded with the state of the joint cartilage and thus the stability of the fragment. Fixation must stabilize the fragment but not prevent further consolidation via osteogenesis. This is why deep perforations are drilled beyond the ossified area and additional osteochondral grafts are used. The Wagner operation gives less satisfactory results than more complicated procedures. Removal of a sequestrum is a simple, minimally invasive procedure with an uneventful postoperative period, but in the long term it favors osteoarthritic degradation, especially when performed in adults. Mosaic grafts give good mid term results. Morbidity is low especially if the grafts are harvested above the notch. The question of chondrolysis around the grafts was beyond the scope of this study. Chondrocyte grafting is difficult to accomplish and is expensive. The mid term results are good for large lesions. Osteotomy is logical only in the event of early stage osteoarthritic degradation. DECISION ALGORITHM IN CHILDREN AND ADOLESCENTS: If the plain x-ray reveals a defect (class I), simple interruption of sports activities should be proposed. Two situations can then develop. First, in a certain number of patients, the pain disappears as the defective zone ossifies progressively. Complete cure is frequent before the age of 12 years. In the second situation, the knee remains painful and the x-ray does not change or worsens to a class II nodular formation. In this case an MRI must be obtained to determine whether the joint cartilage is normal. There are two possibilities. First, the osteochondral fragment is viable and most probably will become completely re-integrated, particularly if the lesion is far from the growth plate. Necrosis is the other possibility. Transchondral perforations are needed in this case. If on the contrary the cartilage is altered, there is little hope for spontaneous cure. Arthroscopy may be needed to complete the exploration. Fragments, especially if there is a large surface area, must be fixed. Perforations to favor revascularization are certainly useful here. In the last situation (class III), the fragment wobbles on a thin attachment or has already fallen into the joint space. This is the type of problem generally observed in adults. The decision algorithm in adults is the same as in children for the rare nodular aspects (class II). There could be a discussion between transcartilage perforation and fixation. If there are a large number of fragments, fixation may not be fully successful and the lesion might be considered class III. For class III lesions, three operations can be used: removal of the sequestrum, mosaic bone-cartilage grafts, or autologous chondrocyte grafts. At the same follow-up, mosaic grafts give better results than excision of sequestra. It may be useful to remove sequestra in a limited number of situations: if there is just a small area of osteochondritis, the lesion is old and partially healed, or the zone is non weight-bearing. For other lesions, we favor mosaic grafts. We still do not have enough follow-up to assess the long-term outcome with these mosaic grafts, but simple excision clearly favors osteoarthritic degradation. Can chondrocytes grafts be compared with mosaic grafts? Chondrocyte grafts have been used for very large lesions and have given results similar to mosaic grafts. It might also be possible to combine fixation of a loose fragment and a mosaic graft. LESSONS FROM THIS STUDY: 1) The prognosis of osteochondritis is better before than after fusion of the growth plate but the lesion does not always heal in children. 2) Presence of osteochondritis requires complementary anatomic and functional exploration to determine the stability and the vitality of the fragment. 3) Attention must be taken to perform transchondral perforations early enough, particularly in children. 4) Screw fixation is not always sufficient. The trophicity of the fragment and its blood supply must be improved. 5) Mosaic grafts are preferable to excision of the fragment. 6) Chondrocyte grafts will be more widely used in the future.

Grapefruit juice-nifedipine interaction: possible involvement of several mechanisms

OBJECTIVE

To develop a model based on mean residence time for better understanding the effect of grapefruit juice on the metabolism of nifedipine (NIF).

MATERIAL AND METHODS

Sixteen healthy volunteers from an urban population were included. For each trial, the subjects drank water, fresh grapefruit juice or bottled grapefruit juice. Thirty minutes later, the subjects took a 10 mg capsule of NIF, orally. Plasma concentration of NIF was measured and the kinetic parameters were calculated with a non-compartmental model.

RESULTS

Grapefruit juice increased the bioavailability of NIF, but did not significantly reduce the drug's metabolism as shown by the approximately constant metabolite to parent drug AUC ratio (P = 0.948). There was no significant increase in the amount of non-metabolized drug absorbed during first-pass: 0.12 and 0.16 (P = 0.470) without and with grapefruit juices respectively. There was an increase in the relative bioavailability (P = 0.039) and the apparent volume of distribution (Vdm) (P = 0.025) of dehydronifedipine with grapefruit co-administration. A second peak was also observed in the NIF plasma-concentration profile when the drug is co-administered with grapefruit juice. Therefore, the most likely explanation for the double peak phenomenon is a delay in gastric emptying (+32 min with grapefruit juice) caused by the pH of grapefruit juice.

CONCLUSION

This study shows that grapefruit juice interferes with the metabolism of NIF by inhibiting NIF metabolism and slowing down the rate of gastric emptying. This study also confirms that the metabolic inhibition is not a first pass effect, but is a secondary oxidative step.

[The Dijon Physical Activity Score: reproducibility and correlation with exercise testing in healthy elderly subjects]

PURPOSE

To validate a French physical activity score for current use in healthy elderly people.

PATIENTS AND METHODS

A brief questionnaire was developed for healthy elderly subjects older than 72 years. Questions asked about self-assessed physical fitness (1), daily activity (2), leisure and sport activity (5) and rest time (1). Correlations were searched between the score and several parameters of physical fitness: maximal exercise stress test (peak VO(2)), six-minute walk test, 200-meter long walk test, timed up an go test.

RESULTS

A total of 57 subjects were studied (mean age, 77.6 +/-3.6 years; 28 females and 29 males). The mean time to complete the questionnaire was 3.96 minutes. Reproducibility was 0.606, as determined by Spearman's coefficient. Correlations were found between the physical activity score and peak VO(2) (0.302, P <0.05) and peak power (0.257, P <0.10).

CONCLUSIONS

This easily obtained physical activity score provides a new way to assess physical activity in active elderly subjects. The physical score correlated in part with maximal ability but must be validated in several diseases.

Echo-planar rotating-frame imaging

A new rotating-frame imaging method that produces a complete cross section of an object in a single experiment is reported. The echo planar rotating frame imaging (EPROFI) technique uses two perpendicular RF gradients for two-dimensional spatial encoding and fully exploits the formation of rotary echoes for fast sampling of spatial frequencies. The acquisition scheme yields the Fourier transform of the spin distribution on Cartesian coordinates for straightforward image reconstruction. Implementation of the technique on a low-field portable NMR probe is described and results are presented for test objects with different geometries.

Transchondral drilling for osteochondritis dissecans of the medial condyle of the knee

Osteochondritis dissecans is a rare condition which occurs most frequently in the medial condyle of the knee. Its prognosis remains controversial. We report our experience with transchondral drilling (TCD) for osteochondritis dissecans. The rationale for this low-morbidity procedure is to enhance the healing potential of a lesion which failed to heal after conservative treatment. This multicenter retrospective study examined 24 patients (25 medial condyles), including cases both before (juvenile osteochondritis dissecans, JOCD; n=17) and after closure of the physis (adult osteochondritis dissecans, AOCD; n=8). All patients initially underwent a prolonged conservative treatment. The mean duration of symptoms prior to surgery was 22 months in JOCD and 55 months in AOCD patients. TCD was proposed in cases of intact or almost intact articular cartilage and was initially conducted under arthrotomy and later by arthroscopy. Mean follow-up time was 11.8 years in JOCD and 6 years in AOCD, and evaluation was based on clinical examination and radiography. Excellent clinical results were only observed in the JOCD group (12/17). In the AOCD group 4 patients had a good result and the other 4 a poor result. Radiological findings matched with clinical results. Except for age, factors of poor prognosis were: fissure of the articular cartilage and anterior extension of the lesion. We do not recommend TCD for AOCD. In JOCD, failure after 12 months of conservative treatment should indicate TCD in the cases where the cartilage remains continuous. At this stage there is no indication for more aggressive procedures.

LC determination of oxcarbazepine and its active metabolite in human serum

Twenty-five percent of epileptic patients present refractory seizures to current frontline antiepileptic drugs, needing new treatments and leading to the introduction of several new AEDs, among which is oxcarbazepine (Trileptal). This 10-ketoanalogue of carbamazepine seems to be a weaker inducer of cytochrome P450 3A4. However, pharmacokinetic interactions with clinical significance have already been reported, before the marketing of Trileptal in France. The aim of this study was to develop and validate a HPLC method allowing simultaneous dosage of oxcarbazepine, 10-hydroxycarbamazepine, epoxycarbamazepine, carbamazepine, phenobarbital and phenytoïn. After plasma defecation by acetonitrile, dosage was obtained by analysis of the supernatants on a C(18) reversed-phase column coupled with UV detection (240 nm). The statistical validation was performed according to the recommendations of a European technical commission. This method seems to provide a quite good selectivity from the psychotropic therapeutics, which is commonly coprescribed with AEDs. Linearity was established for the whole concentration range, whatever the compound. Quantization limits of oxcarbazepine, 10-hydroxycarbamazepine, epoxycarbamazepine, carbamazepine, phenobarbital and phenytoïn are 0.58, 3.5, 2.35, 0.66, 1.02 and 3.13 microg/ml, respectively, and absolute recoveries are 105.15, 84.76, 94.45, 96.52, 98.62 and 95.08%, respectively.

Simultaneous determination of four antiepileptic drugs in serum by high-performance liquid chromatography

A high-performance liquid chromatographic method has been developed for the simultaneous determination of oxcarbazepine, 10-hydroxycarbamazepine, epoxycarbamazepine, carbamazepine, phenobarbital and phenytoin. After protein precipitation by acetonitrile, the supernatant was analysed on a C18 reversed-phase HPLC column. Antiepileptic drugs and oxazepam (internal standard) were detected by ultraviolet absorbance at 240 nm. Linearity was established for the whole concentration range for each compound. Quantitation limits of oxcarbazepine, 10-hydroxycarbamazepine, epoxycarbamazepine, carbamazepine, phenobarbital and phenytoin were 0.58, 3.5, 2.35, 0.66, 1.02 and 3.13 microg/mL, respectively, and mean recoveries added to serum were 105.15, 84.76, 94, 45, 96.52, 98.62 and 95.08%, respectively. This method has been used for the simultaneous determination of steady-state serum concentration of antiepileptic drugs in patients treated by one or more anticonvulsive treatment.

[Techniques for repair of chondral and osteochondral lesions in the knee. Principles of rehabilitation]

The objective of the present study is to assess the techniques, indications and management of the three principal repair methods of cartilaginous lesions of the knee. Arthroscopic irrigation and debridement are excluded. The most important articles of the last 20 years have been evaluated favouring those written by the protagonists of the technique and those with the longest follow-up. Each technique, i.e. the microfractures, the osteochondral grafts and the chondrocyte grafts, is explained in detail with its surgical principles, management of specific reeducation and results. Postoperative treatment is not very different during the first weeks; for condyle lesions protection of the graft site is mandatory by strict avoidance of non weight bearing, whereas immediate mobilisation of the knee is possible; for patellar lesions, weight bearing is permitted whereas flexion is limited. Later, the delay concerning resumption of weight bearing, muscular training and sports is specific for each technique. These three techniques are only apply to symptomatic lesions of the condyle at the weight-hearing zone or the femoro-patellar site in young patients. The degenerative knee, even in its beginning, is excluded. Those lesions can be linked to rupture of the anterior cruciate ligament and immediate cartilaginous repair is discussed.

Improving resolution in fast rotating-frame experiments

The rapid rotating-frame technique allows significant reduction in data-acquisition time compared with the two-dimensional method by stroboscopic observation of the nuclear magnetization during its evolution in the rotating frame. A onefold reduction in the dimensionality of the original rotating-frame experiment is achieved by using a train of strong radiofrequency pulses separated by short acquisition windows. The penalty for shortening experimental time is a reduction in spectral resolution compared with the two-dimensional method due to relaxation of transverse magnetization components during the observation windows. A variant of the rapid-rotating frame technique for improving spectral resolution based on undersampling and self-phase encoding is presented. An M-fold resolution improvement requires M experiments, thus, making possible a tradeoff between spectral resolution and experimental time. The technique was applied for spatial localization of quadrupole nuclei in powder solids, and resolution improvement is demonstrated on one- and two-dimensional NQR images.

Influence of seven beverages on salicylate disposition in humans

OBJECTIVE

Aspirin administered orally is one of most widely self-prescribed drugs to treat headaches or other pains. The aim of this study was to evaluate whether the influence of different beverages may be used to help in the ingestion of an aspirin tablet on the pharmacokinetic parameters of this drug.

METHOD

This study was undertaken in five healthy volunteers. Seven beverages were tested: water, tea, coffee, orange juice, milk, beer and 40 degrees distilled alcohol. After plasma extraction, aspirin and salicylic acid were measured by HPLC with UV detection. The main pharmacokinetic parameters were determined by the compartimental method and drug disposition profiles by the Wagner-Nelson modified method.

RESULTS

Elimination was not modified by any of the beverages but absorption was affected. Two opposing effects were observed: 40 degrees alcohol seemed to increase AUC and Cmax. Milk and beer seemed to decrease these parameters. With 40 degrees alcohol and tea, the amount absorbed and the disposition rate were higher. For milk and orange juice, the amount absorbed was lower and the disposition rate was unaffected. For beer, both the amount absorbed and the disposition rate increased. For coffee, both the amount absorbed and disposition rate were not significantly modified.

CONCLUSION

The bioavailability of salicylates on the healthy volunteers in this study was significantly affected by concomitant administration of 40 degrees alcohol (spirit), beer and milk. The beverages seem to interfere with aspirin absorption and the drug disposition profile was modified.

Solid state proton imaging detected by quadrupole resonance

A double resonance method for imaging of solid materials containing quadrupole nuclei via the coupled protons is reported. The technique uses a static field gradient to encode the position on the protons and the method of double resonance spin-echo to detect the occurrence of proton resonances by affecting the zero-field echo signal from the quadrupole system. The double resonance imaging method offers the advantages of higher spatial resolution and straightforward image reconstruction for powder samples compared with rotating-frame and Zeeman-perturbated nuclear quadrupole resonance encoding techniques.

Polycomb group genes control pattern formation in plant seed

Transcriptional activators of the Trithorax group (TRX-G) and repressors of the Polycomb group (Pc-G) are involved in multiple aspects of embryogenesis in Drosophila and the mouse [1, 2] and appear to have a conserved role in the zygotic control of the development of the anterior-posterior axis [3, 4, 5]. In the model plant Arabidopsis, three Pc-G genes have been isolated and characterized to date. CURLY LEAF (CLF) represses the expression of a floral homeotic gene in vegetative tissues but does not appear to have a role in plant embryogenesis [6]. Two other Pc-G genes, FIS1/MEDEA [7, 8, 9], and FIS3/FIE [8, 10] have been characterized in studies of mutants that produce seeds in the absence of fertilization. Seeds resulting from autonomous development in fis mutants do not contain an embryo but only endosperm, the second product of double fertilization in flowering plants [11, 12]. Thus, FIS genes are considered to be repressors of endosperm development before fertilization. We report that when fis ovules are fertilized, the endosperm patterning along the major polar axis is perturbed. Posterior structures develop in more anterior domains of the endosperm. This correlates with the ectopic expression of a posterior molecular marker. FIS genes appear to be potent regulators of the establishment of the anterior-posterior polar axis in the endosperm.

Circular polarization excitation and detection in (14)N NQR

Circular polarization excitation and detection of (14)N NQR signal are reported. A theoretical model is presented in terms of fictitious spin-1/2 operators and is compared to experiments performed on a powder crystalline sample of RDX. It is shown that in spin-1 systems with finite asymmetry--unlike previously reported NMR and symmetric spin-3/2 NQR systems (Chen et al., J. Magn. Reson. 54, 324--327, 1983; Weber and Hahn, Phys. Rev. 120, 365--375, 1960)-the circular polarization nature of the signal is due to powder orientation effects in polycrystalline samples. Sensitivity improvements up to a factor of the square root of 2 are reported using the same hardware and switching modes from linear polarization to circular polarization; this also is shown to result from the polycrystalline nature of the samples.

[Radiotherapy of localized prostatic cancer: follow-up of 48 patients. G.C.C.P. (Cooperative Group for the Study of Prostatic Cancer)]

OBJECTIVE

To evaluate the safety and long-term efficacy of curative-intent radiation therapy in patients with apparently localized prostate cancer.

METHOD

48 patients with T < 3 M0 prostate cancer recruited between 1981 and 1985 received regular clinical follow-up for at least ten years or until their death. Radiation therapy was given according to the protocols established by Ray and Bagshaw.

RESULTS

Radiation therapy was safe and effective in most patients. The rate of escape phenomenon was less than 10% after two years. Tumor control rates were greater than 80% after five years and 50% after ten years. Unfortunately, local remission, even when prolonged, did not necessarily indicate a complete cure: 20% of local recurrences developed five to 11 years after radiation therapy.

CONCLUSION

Radiation therapy may be the best first-line treatment in men older than 75 years of age and in those whose life expectancy seems shorter than ten years, but should probably not be considered curative.

Glycine betaine, carnitine, and choline enhance salinity tolerance and prevent the accumulation of sodium to a level inhibiting growth of Tetragenococcus halophila

Natural-abundance (13)C-nuclear magnetic resonance was used to probe the intracellular organic solute content of the moderately halophilic bacterium Tetragenococcus halophila. When grown in complex growth media supplemented or not with NaCl, T. halophila accumulates glycine betaine and carnitine. Unlike other moderate halophiles, T. halophila was not able to produce potent osmoprotectants (such as ectoines and glycine betaine) through de novo synthesis when cultured in defined medium under hyperosmotic constraint. Addition of 2 mM carnitine, glycine betaine, or choline to defined medium improved growth parameters, not only at high salinity (up to 2.5 M NaCl) but also in media lacking NaCl. These compounds were taken up when available in the surrounding medium. The transport activity occurred at low and high salinities and seems to be constitutive. Glycine betaine and carnitine were accumulated by T. halophila in an unmodified form, while exogenously provided choline led to an intracellular accumulation of glycine betaine. This is the first evidence of the existence of a choline-glycine betaine pathway in a lactic acid bacterium. An assay showed that the compatible solutes strikingly repressed the accumulation of glutamate and slightly increased the intracellular potassium level only at high salinity. Interestingly, osmoprotectant-treated cells were able to maintain the intracellular sodium concentration at a relatively constant level (200 to 300 nmol/mg [dry weight]), independent of the NaCl concentration of the medium. In contrast, in the absence of osmoprotectant, the intracellular sodium content increased sharply from 200 to 2,060 nmol/mg (dry weight) when the salinity of the medium was raised from 1 to 2 M. Indeed, the imported compatible solutes play an actual role in regulating the intracellular Na(+) content and confer a much higher salt tolerance to T. halophila.

Autologous chondrocyte implantation. A review of techniques and preliminary results

The treatment of deep focal bone and cartilage defects in weight-bearing areas of the knee remains challenging. Autologous chondrocyte implantation is a recently introduced alternative to drilling and mosaicplasty and is gaining ground in France under the impetus of favorable results obtained in other countries in highly selected cases. The technique and preliminary results are discussed herein.

Phase-modulated rotating-frame NQR techniques for spatial encoding

The rotating-frame method of localization for spatially resolved spectroscopy and imaging in the pure quadrupole regime relies on a gradient B(1) field in which spins experience a flip angle dependent on their position in the B(1) field strength. So far, the techniques have been implemented as amplitude-modulated methods, i.e., the spatial nuclear quadrupole distribution is encoded in the amplitude of the free-induction decay signals. In this work, we describe the implementation of phase-modulated variants of both two-dimensional and rapid rotating-frame imaging techniques. The experiments are discussed for both single crystalline and powder samples. The phase-modulated experiment offers some advantages over the amplitude-encoding technique: It enables one to distinguish the sign of the spatial coordinate and the signal-to-noise ratio is higher than for the simplest amplitude-encoding method. Copyright 1999 Academic Press.

Iron deficiency in older people: interactions between food and nutrient intakes with biochemical measures of iron; further analysis of the National Diet and Nutrition Survey of people aged 65 years and over

OBJECTIVE

To quantitatively investigate relationships between food consumption, nutrient intake and biochemical markers of iron status in a population of older people.

DESIGN

National Diet and Nutrition Survey: cross-sectional survey of a nationally representative population of men and women aged 65 y and over.

SETTING

Mainland Great Britain

SUBJECTS

1268 participants (651 men and 617 women) who provided both dietary intake and blood biochemistry. 986 were living in private households and 282 were living in residential or nursing homes.

RESULTS

Intakes of alcohol, vitamin C, protein, haem and non-haem iron and fibre were positively associated with iron status. Consumption of meat, poultry and fish were positively associated with six measures of iron status, and vegetables and potatoes with four measures. Calcium, dairy foods and tea generally had a negative association with most measures of iron status.

CONCLUSIONS

A varied diet containing meat, poultry and fish, vegetables and fruit, with a moderate intake of alcohol will make a positive contribution to the iron status of elderly people.

Clozapine-olanzapine: a potentially dangerous switch. A report of two cases

BACKGROUND

Withdrawal symptoms associated with switch between two typical antipsychotics are generally rare and mild. In contrast, switching from clozapine to risperidone can be lead to severe withdrawal symptoms. Different pathophysiologic aetiologies have been suggested for explaining these severe symptoms, including cholinergic supersensitivity and rebound. Theoretically, the switch from clozapine to olanzapine should not lead to any problems because those two agents have the same affinity in vitro for muscarinic receptors.

OBJECTIVE

This study reports two cases of switches from clozapine to olanzapine, in refractory schizophrenic patients, which were associated with severe withdrawal symptoms.

RESULTS

After the switch, the two patients developed diaphoresis, hypersialorrhea, bronchial obstruction, agitation, anxiety and enuresis. The symptoms were treated with anticholinergic medication and by an increase in dose of olanzapine to 20 mg/day. For one of the patients this treatment led to normalization of secretion. For the other patient, a superinfection leading to a bilateral pneumopathy which required emergency hospitalization in a general hospital was observed.

CONCLUSION

The symptomatology and the response to treatment lead to the hypothesis of a muscarinic from abrupt weaning. The withdrawal symptoms disappeared rapidly with an increase in olanzapine dosage and with anticholinergic started at the beginning of the switch. We recommend slow clozapine weaning over 3 weeks or more with concurrent anticholinergic treatment.

The possibilities of using the patellar tendon in the treatment of anterior cruciate ligament tears in children

We describe a technique of reconstruction for complete midsubstance ruptures of the anterior cruciate ligament in patients with wide open physis, using the central third of the patellar tendon. This specific procedure is named the Clocheville technique. Results were very good in five cases and good in three cases at 2 years minimal follow-up. We neither noticed angular deformity, nor significant change in lower leg length. The Clocheville technique is an excellent alternative for young patients, with residual growth of the knee greater than 15 mm, if presenting an objective instability in activities of daily living or a proven meniscal tear that should be repaired.

Pharmacokinetics of midazolam: comparison of sublingual and intravenous routes in rabbit

In France, the legal routes used to administer midazolam to a patient are intravenously and intramuscularly. For anaesthetists, these routes are not well adapted to paediatric use; they lead to pain at injection site and stress on children. The sublingual route should be a good compromise between stress and quick efficiency. We have developed a sublingual tablet of midazolam. The aim of the present investigation is to compare the pharmacokinetic parameters of midazolam tablets administered by the sublingual and intravenous routes in 6 rabbits to determine the bioequivalence between these routes. We have estimated the 1-hydroxy-midazolam serum level by difference between RRA and HPLC values. By the sublingual route, midazolam absorption is substantial and fast. The statistical analysis, on data obtained with HPLC dosage, shows no significant difference between pharmacokinetic parameter values calculated after intravenous and sublingual administration (0.5 mg). The absolute bioavailability was close to 100%. With RRA dosage, however, AUCs were greater than those obtained by HPLC dosage (174%). 1-hydroxy-midazolam seems to have a great importance in BZD activity. To estimate the bioequivalence between intravenous and sublingual midazolam administration, it is necessary to take into account the active metabolites.

Mapping molecular orientation in solids by rotating-frame NQR techniques

A multi-dimensional NQR technique to image both the spatial distribution of quadrupolar nuclei and the local orientation of the electric field gradient tensor at the quadrupole sites in solids is reported. The encoding procedure is based on the irradiation of the sample by a pulse sequence composed of spatially homogeneous and inhomogeneous radiofrequency fields. A method that encodes the spatial and orientation information in the amplitudes of the free-induction decay signals and a proper three-dimensional reconstruction procedure that yields the space-orientation-dependent NQR spectra are described. A two-dimensional variant allows rapid measurement of the spatially dependent orientation distribution of molecules, disregarding the spectroscopic information. Copyright 1998 Academic Press.