[Oral appliances or maxillomandibular advancement osteotomy for severe obstructive sleep apnoea in patients refusing CPAP]

OBJECTIVES

The management of patients with severe obstructive sleep apnea syndrome (OSAS) refusing or not tolerating continuous positive pressure ventilation (CPAP) remains problematic. We evaluated the effectiveness of oral appliances and of maxillomandibular advancement osteotomy.

METHODS

One hundred and two patients with severe OSAS were included between 2001 and 2006. Maxillo-mandibular advancement osteotomy was proposed to patients less than 60 years of age, non obese and without comorbidities. The other patients were treated with oral appliances. All patients underwent polysomnography at 3 months.

RESULTS

Group A: 25 patients with mean apnea-hypopnea index (AHI) at 45/h were treated by maxillo-mandibular advancement. Three months after the surgery, AHI had decreased from 45 to 7. The success rate was 89% when AHI was less than 15/h and 74% when AHI was less than 10/h. Sixteen patients performed a polysomnography one year after surgery with similar results. There were no major postoperative complications. Group B: 77 patients with a mean AHI at 41/h were treated with oral appliances. Only 23 patients underwent polysomnography at 3 months. The mean AHI had decreased from 41/h to 22/h. The success rate was 56% when AHI was less than 15/h and 30% when AHI was less than 10/h.

DISCUSSION

We are confronted with an increasing number of severe OSAS patients with CPAP failure or intolerance. Surgery for maxillo-mandibular advancement is an effective alternative. However, it is not always indicated or accepted by the patient. So an oral appliance remains a useful therapeutic option despite its moderate success rate.

Mass spectrometric determination of acromelic acid A from a new poisonous mushroom: Clitocybe amoenolens

As Clitocybe acromelalga, the mushroom Clitocybe amoenolens is responsible for erythermalgia. Acromelic acids isolated from C. acromelalga have been suspected to be to some extend the active principles. The objective was to develop a specific and sensitive liquid chromatographic-mass spectrometric method that would allow acromelic acid A identification and quantification in mushrooms. The method involved a single-step methanol-water extraction followed by a selective cleanup of the extract with solid-phase extraction cartridges (strong-anion exchange). The chromatographic separation was achieved on a porous graphitic carbon column with acetonitrile-water-formic acid as mobile phase. Detection was done with a mass analyzer equipped with a TurboIonSpray source, operated in the negative ionization mode. Acromelic acid A concentration was determined in dried mushroom at around 325 ng/mg in C. amoenolens and 283 ng/mg in C. acromelalga.

Oxidative stress and baroreflex sensitivity in healthy subjects and patients with mild-to-moderate hypertension

Decreased baroreflex sensitivity (BRS) is a prognostic marker in essential hypertension. Animal experiments suggest that decreased BRS is related to increased oxidative stress. Our study was aimed at testing whether oxidative stress, estimated by isoprostane 15-F(2t)-IsoP urinary levels, is correlated to BRS variation in healthy subjects as well as in patients suffering from essential hypertension. Urinary 15-F(2t)-IsoP levels and BRS were evaluated in two groups of subjects: healthy volunteers (n=64) and patients with untreated mild-to-moderate hypertension (n=33). Data were analysed in 61 and 31 subjects, respectively, BRS analysis being impossible in three and two subjects, respectively. 15-F(2t)-IsoP levels were measured using gas chromatography/mass spectrometry. BRS was measured using the sequence method [PS+/RR+ and PS-/RR-] and crossspectral analysis (CSP) (MF gain) at rest, lying down. No significant correlation was found between basal urinary 15-F(2t)-IsoP levels and BRS (sequence method and CSP) in either healthy controls or hypertensive patients. Our study shows that oxidative stress is not involved in interindividual variations of BRS in healthy subjects and patients suffering from mild-to-moderate hypertensionJournal of Human Hypertension (2004) 18, 517-521. doi:10.1038/sj.jhh.1001684 Published online 12 February 2004

Automated solid-phase extraction and liquid chromatography-electrospray ionization-mass spectrometry for the determination of flunitrazepam and its metabolites in human urine and plasma samples

A sensitive and specific method using reversed-phase liquid chromatography coupled with electrospray ionization-mass spectrometry (LC-ESI-MS) has been developed for the quantitative determination of flunitrazepam (F) and its metabolites 7-aminoflunitrazepam (7-AF), N-desmethylflunitrazepam (N-DMF) and 3-hydroxyflunitrazepam (3-OHF) in biological fluids. After the addition of deuterium labelled standards of F,7-AF and N-DMF, the drugs were isolated from urine or plasma by automated solid-phase extraction, then chromatographed in an isocratic elution mode with a salt-free eluent. The quantification was performed using selected ion monitoring of protonated molecular ions (M+H(+)). Experiments were carried out to improve the extraction recovery (81-100%) and the sensitivity (limit of detection 0.025 ng/ml for F and 7-AF, 0.040 ng/ml for N-DMF and 0.200 ng/ml for 3-OHF). The method was applied to the determination of F and metabolites in drug addicts including withdrawal urine samples and in one date-rape plasma and urine sample.

Increased lipid peroxidation in patients with pulmonary hypertension

Isoprostanes are chemically stable lipid peroxidation products of arachidonic acid, the quantification of which provides a novel approach to the assessment of oxidative stress in vivo. The main objective of this study was to quantify the urinary levels of isoprostaglandin F(2alpha) type III (iPF(2alpha)-III), an F(2)-isoprostane, in patients with pulmonary hypertension (PHT) in comparison with healthy controls. The secondary objective was to test whether baseline iPF(2alpha)-III levels correlate to the reversibility of pulmonary hypertension in response to inhaled NO challenge. Urinary iPF(2alpha)-III levels were measured by gas chromatography-mass spectrometry in 25 patients with PHT, 14 of whom were investigated for response to inhaled NO challenge. Urinary iPF(2alpha)-III levels in PHT patients (225 +/- 27 pmol/mmol creatinine) were 2.3 times as high as in controls (97 +/- 7 pmol/mmol creatinine, p < 0.001). The mean pulmonary arterial pressure variation and the pulmonary vascular resistance variation in response to inhaled NO were correlated to basal iPF(2alpha)-III levels. This study shows that oxidative stress is increased in patients with pulmonary hypertension. Furthermore, iPF(2alpha)-III levels inversely correlate to pulmonary vasoreactivity. These observations are consistent with the hypothesis that free radical generation is involved in PHT pathogenesis.

Formation of isoprostanes in children with type IIa hypercholesterolemia

F2-isoprostanes are stable lipid peroxidation products of arachidonic acid and their quantification provides a novel approach to the assessment of oxidative stress in vivo. F2-isoprostanes are present in increased amounts in adult hypercholesterolemia, but no data exist concerning children. We investigated urinary isoprostaglandin F2, type III production as an index of lipid peroxidation in 15 children presenting with type IIa hypercholesterolemia (serum total cholesterol, 290 [SD +/- 70] mg/dl; low-density lipoprotein cholesterol, 210 [SD +/- 90] mg/dl) compared with 15 sex- and age-paired control children (serum total cholesterol, 160 [SD +/- 20] mg/dl). Urinary levels of isoprostaglandin F2alpha type III were measured by gas chromatography mass spectrometry. Urinary concentrations did not differ significantly in hypercholesterolemic children compared with control children (84.7 [SD +/- 37] vs. 96 [SD +/- 35] pmol/mmol creatinine, respectively). No significant correlation was found with total cholesterol, low-density-lipoprotein and high-density-lipoprotein cholesterol, and apolipoprotein B and A1 serum levels. F2-isoprostane urinary levels in children with type IIa hypercholesterolemia do not differ from those of age- and sex-matched control children and are not correlated to blood lipid parameters, suggesting that hypercholesterolemia is not associated with increased lipid peroxidation in childhood.

Determination of isoprostaglandin F2alpha type III in human urine by gas chromatography-electronic impact mass spectrometry. Comparison with enzyme immunoassay

F2-Isoprostanes are stable lipid peroxidation products of arachidonic acid, the quantification of which provides an index of oxidative stress in vivo. We describe a method for analysing isoprostaglandin F2alpha type III (15-F2t-IsoP) in biological fluids. The method involves solid-phase extraction on octadecyl endcapped and aminopropyl cartridges. After conversion to trimethylsilyl ester trimethylsilyl ether derivatives, isoprostaglandin F2alpha type III is analysed by mass spectrometry, operated in electronic impact selected ion monitoring mode. We have compared enzyme immunoassay (EIA; Cayman, Ann Arbor, MI, USA) to this method with 30 human urine aliquots following the same extraction procedure in order to determine the agreement between both methods. Isoprostaglandin F2alpha type III concentrations determined with gas chromatography-mass spectrometry (GC-MS) did not agree with those determined with EIA. Our results suggest that GC-MS and EIA do not measure the same compounds. As a consequence, comparison of clinical results using GC-MS and EIA should be avoided.

The hair analysis proficiency testing program of the French Society of Analytical Toxicology

In an effort to improve laboratories performing hair analysis in forensic cases, the French Society of Analytical Toxicology (S.F.T.A.) has implemented a proficiency testing program since 1992. Actually about 10 laboratories are participating. Each survey is dedicated to one analyte or one pharmacological class: opiates (6-monoacetylmorphine, morphine and codeine), cocaine and benzoylecgonine, tetrahydrocannabinol, buprenorphine and norbuprenorphine, beta-blockers (metoprolol, atenolol), beta 2-agonists (salbutamol, clenbuterol). Animal hair was tested for clenbuterol. Prior to sending, hair samples were reduced to a powdered form, well mixed to ensure homogeneity, and then tested by GC/MS or HPLC/MS. Results confirm those obtained in a preliminary study on opiates and cocaine analysis in hair: a common analytical procedure has to be used by all the participants, including hydrolysis of hair. It is essential to work on authentic drug-positive hair samples and not on spiked samples. Participation at this program is free of charge and considered as an educational tool. Comparison of the results with those of other laboratories in Europe and USA shows that the analytical methods used during this program are in accordance with all the other procedures.

Determination of buprenorphine and norbuprenorphine in urine and hair by gas chromatography-mass spectrometry

Buprenorphine, which is used in France as a substitution drug for opioid addiction, is widely abused, and several fatal cases have been reported. In order to confirm a recent intoxication or to establish retrospectively chronic abuse, a simple and reliable gas chromatographic-mass spectrometric method was developed and validated for quantitation of buprenorphine and its active metabolite norbuprenorphine in urine and hair. Two milliliters of urine or 50 mg of pulverized hair was submitted to a pretreatment (enzymatic hydrolysis for urine and decontamination with dichloromethane followed by incubation in 0.1 M HCI for hair). Buprenorphine-d4 was chosen as the internal standard. Selective solid-phase extraction with Bond Elut Certify columns provided recoveries higher than 85% for urine and 43% for hair. By using a mixture of MSTFA/TMSIM/TMCS (100:2:5), buprenorphine and norbuprenorphine produced stable silylated derivatives. The detection was carried out with a quadrupole mass detector working in El selected ion monitoring mode. Ions at m/z 450 and 468 were chosen for the quantitation of buprenorphine and norbuprenorphine, respectively (m/z 454 was used for the internal standard). Limits of quantitation were 0.25 and 0.20 ng/mL, respectively, for buprenorphine and norbuprenorphine in urine and 0.005 ng/mg for the two compounds in hair. Calibration curves were linear from 0 to 50 ng/mL in urine and from 0 to 0.4 ng/mg in hair. Between-day and within-day precisions were less than 8.4% in hair and 6.1% in urine for both molecules in all cases. This method was applied to urine and hair samples collected from patients in a withdrawal treatment program and demonstrated its good applicability in routine analysis and its benefit for clinicians. This technique, which requires instruments already available to many toxicology laboratories, offers an attractive alternative to more sophisticated techniques.

Gas chromatographic quantitation of dextropropoxyphene and norpropoxyphene in urine after solid-phase extraction

A gas chromatographic technique with flame ionization detection, which is based on a solid-phase extraction (SPE) procedure using mixed-mode SPE columns, for the simultaneous quantitation of dextropropoxyphene and norpropoxyphene in urine is presented. Urine is treated with sodium hydroxide in order to rearrange, by base catalysis, norpropoxyphene to norpropoxyphene amide, which is then extracted with these columns and chromatographed. The method is specific, linear over the range 0-2000 ng/mL, sensitive, and reproducible. The extracts are cleaner than those obtained with traditional liquid-liquid extraction procedure, which is an important feature in view of further mass spectrometric confirmation of narcotics and other drugs.

Simultaneous determination of zolpidem and zopiclone in human plasma by gas chromatography-nitrogen-phosphorus detection

A simple, specific and selective method for the simultaneous determination of zolpidem and zopiclone in human plasma is described. After a liquid-liquid extraction, the extract is injected into a capillary gas chromatograph with an OV-1 fused-silica column coupled to a nitrogen-phosphorus detector. The detection limits are 1 and 2 ng/ml for zolpidem and zopiclone, respectively. The method described is reproducible and linear over a range of concentrations, rendering it suitable for use for pharmacokinetic studies or toxicological evaluations. Absolute identification of the chromatographed compounds is accomplished by gas chromatography--mass spectrometry in both electron-impact and positive-ion chemical ionisation modes.