Serum leptin levels and leptin expression in growth hormone (GH)-deficient and healthy adults: influence of GH treatment, gender, and fasting

Growth hormone (GH) treatment is associated with a reduction in fat mass in healthy and GH-deficient (GHD) subjects. This is mainly mediated via a direct GH action on adipose cells and stimulation of lipolysis. Leptin is secreted from adipose tissue and may be involved in signaling information about adipose tissue stores to the brain. Hormonal regulation of leptin is still not fully elucidated, and in the present study, we investigated both the long-term (4-month) and short-term (28-hour) GH effects on serum leptin and leptin gene expression in subcutaneous adipose tissue. In GHD adults (n = 24), leptin correlated with most estimates of adiposity (r = .62 to .86), as previously found in healthy subjects. However, no correlation was observed with intraabdominal fat determined by computed tomographic (CT) scan (INTRA-CT). GH treatment for 4 months had no independent effect on either serum leptin or leptin gene expression. In a short-term study, we found that fasting gradually reduced leptin levels in both healthy men and GHD adults, with a maximum reduction of 58% to 60% (P < .01) after 31 hours. No independent effect of GH suppression or GH substitution on serum leptin was found during fasting. Adipose tissue leptin mRNA correlated with serum leptin (r = .51, P < .01) and the body mass index ([BMI] r = .55, P < .05). Serum leptin levels and gene expression were significantly higher in women compared with men (26.6 +/- 5.8 v 10.0 +/- 1.30 ng/mL, P < .05). However, in regression analysis accounting for the gender differences in subcutaneous femoral adipose tissue (FEM-CT), the difference in serum leptin disappeared, indicating that subcutaneous femoral fat or factors closely related to femoral fat (eg, sex hormones) may be causal factors for the gender difference in leptin.

Epidemiology of respiratory syncytial virus infection requiring hospitalization in East Denmark

BACKGROUND

Prophylaxis against infection caused by respiratory syncytial virus (RSV) with high titered RSV immunoglobulin or humanized antibody may soon be available in Europe.

OBJECTIVE

To study the epidemiology of RSV infections requiring hospitalization in infants <6 months in East Denmark to provide a rational basis for decisions concerning prophylaxis against RSV.

METHOD

Populat ion-based retrospective review of case records of infants <6 months admitted to pediatric departments with RSV infection in East Denmark from November 1, 1995, to April 30, 1996.

RESULTS

Data were obtained from 459 infants. Seventy-three had predisposing conditions: prematurity, 49; pulmonary disease, 2; congenital heart disease, 7; neurologic disease, 6; others, 9. One preterm infant had bronchopulmonary dysplasia. The incidence of RSV infection requiring hospitalization in East Denmark among infants <6 months was estimated to be 34/1000/season. It was 32/1000/season among term infants and 66/ 1000/season among preterm infants (P<0.001). Infants with predisposing conditions and/or nosocomial infection (n = 24) had significantly more severe courses than otherwise healthy infants (P<0.01). One-hundred thirty infants received respiratory support by nasal continuous positive airway pressure, but only six required mechanical ventilation. No infants died.

CONCLUSION

The course of RSV disease in East Denmark was milder than reported elsewhere, possibly as a result of the low prevalence of bronchopulmonary dysplasia in Denmark. However, RSV constitutes a considerable burden to the Danish pediatric health care system, and therefore prophylaxis against RSV is desirable.

Major haemorrhagic complications during oral anticoagulant therapy in a Danish population-based cohort

OBJECTIVES

To estimate the incidence of bleeding leading to death or hospital admission in out-patients treated with oral anticoagulants.

DESIGN

Population-based historical cohort study 1 January 1992 to 31 September 1994.

SETTING

The County of North Jutland, Denmark (488,000 inhabitants).

SUBJECTS

Six hundred and eighty-two consecutive patients commencing oral anticoagulant therapy.

MAIN OUTCOME MEASURES

Fatal bleeding or bleeding demanding hospital admission.

RESULTS

In 756 treatment-years of follow-up, there were 45 major haemorrhagic events (6.0 per 100 treatment-years) in 42 patients, of which seven (0.9 per 100 treatment-years) were fatal. The risk of a first major haemorrhagic episode was highest during the first 90 days of treatment compared with duration above one year (incidence rate ratio, IRR, 1.9; 95% CI, 0.8-4.1). The rate was highest above the age of 60 years, 6.8 per 100 treatment-years, compared with 2.9 per 100 treatment-years below 60 years (IRR 2.3; 95% CI, 1.0-5.6). The rate for a bleeding event was slightly higher in females than in males (IRR 1.3; 95% CI, 0.7-2.3), but did not vary according to type of anticoagulant drug.

CONCLUSIONS

The reported rates of major bleeding in this routine community setting implied a higher bleeding risk than was found in randomized trials or when patients are monitored in specialist anticoagulation clinics.

Effects of long-term total fasting and insulin on ob gene expression in obese patients

In the present study the effect of long-term fasting (6 days) on obese (ob) gene expression was examined in nine severely obese females of 34 +/- 3 years and with a body mass index of 46.4 +/- 2.3 kg/m2. Six days of fasting induced a significant weight loss (126.8 +/- 5.3 vs 120.5 +/- 5.1 kg, P < 0.0001). Insulin-stimulated glucose uptake (hyperinsulinemic, euglycemic clamp, insulin infusion rate 1.5 mU/kg per min) was markedly reduced following fasting (M-value 5.96 +/- 0.74 vs 2.79 +/- 0.23 mg/kg per min, P < 0.0001). Ob mRNA/beta-actin concentration in fat biopsies from abdominal subcutaneous adipose tissue was unchanged after 6 days of fasting (1.50 +/- 0.40 vs 1.47 +/- 0.36 arbitrary units, not significant), whereas serum leptin levels decreased significantly from 53.8 +/- 4.7 to 30.7 +/- 2.0 ng/ml (P < 0.0001) during the same period. No significant correlations were found between insulin-stimulated glucose uptake and serum leptin concentration, either prior to the fast or after the fast. Serum leptin levels were unchanged by hyperinsulinemia for 3 h during the clamp prior to the fast, while hyperinsulinemia for 3 h after 6 days of fasting increased serum leptin by 25% (P < 0.01). In conclusion, 6 days of fasting reduced serum leptin by about 40%. In contrast, ob mRNA in abdominal subcutaneous adipose tissue was unchanged. Furthermore, after 6 days of fasting insulin was able to increase the serum level of leptin significantly, indicating that the effect of insulin on the level of leptin is dependent on the nutritional state.

Vitamin D deficiency in pregnant and breast-feeding women and their infants

We describe the cases of five consecutive infants with symptomatic vitamin D deficiency and their mothers. Four of the infants were light skinned, all had poor sunlight exposure, and all were breast-fed or had diets low in vitamin D. All mothers had vitamin D deficiency. Regardless of race, infants with poor sunlight exposure and diets lacking in vitamin D are at risk for vitamin D deficiency. Mothers of these infants should be evaluated for vitamin D deficiency. Vitamin D supplementation of the breast-feeding mother at risk and her infant is recommended.

Long-term (6 months) effect of a new fermented milk product on the level of plasma lipoproteins--a placebo-controlled and double blind study

OBJECTIVE

We have recently demonstrated a short-term hypocholesterolemic effect (reduction of 8-10%) of a new fermented milk product taken for 6 weeks (Agerbaek et al, 1995; Richelsen et al, 1993). The present study was undertaken to investigate the more long-term (6 months) effect of this fermented product on the level of lipoproteins.

DESIGN

The study was randomized, double-blind, and placebo-controlled, and performed for a period of six months.

SUBJECTS

Eighty-seven non-obese and normocholesterolemic females and males, aged 50-70 y old, were included in the study.

INTERVENTION

200 ml of either the fermented milk product or placebo (chemically fermented) were given daily. The test product was fermented with a bacteria culture containing Enterococcus faecium and two strains of Streptococcus termophilus.

RESULTS

After one month the total- and LDL-cholesterol were significantly reduced in the fermented milk group as compared to placebo, LDL was reduced by 0.21 mmol/l vs 0.0 mmol/1 (P < 0.02). The maximal reduction of LDL-cholesterol was reached after 3 months in the test group with a reduction of 0.32 mmol/1 of initial values (P < 0.001). In the placebo group a gradual fall of total- and LDL-cholesterol was observed from 1-6 months of the study. Thus, after six months the reduction of LDL-cholesterol was similar in the two groups (P = 0.95) even though the reduction was significant in both groups in relation to initial values (P < 0.05). No changes in HDL-cholesterol or triglyceride were observed during the study. There were no differences in the response between women and men.

CONCLUSION

The fermented milk product resulted in a rapid reduction of LDL-cholesterol observed after one month but during long-term intake (6 months) the reduction of LDL-cholesterol was similar to the placebo product, indicating that low-fat milk or fermented milk products may have some hypocholesterolemic effects but the present tested product does not seem to be superior in that respect to the placebo milk product used in the present study.

[Vaccination of premature infants]

The article gives a review of the literature concerning immunization of preterm infants. The initial response to diphtheria-tetanus-whole-cell-pertussis vaccine and inactivated polio vaccine may be impaired in preterms, but after two and three doses the responses to these vaccines is comparable to those of term infants of the same chronological age. Likewise, the response to oral polio vaccine is normal and independent of gestational age after two and three doses in preterm infants. After two doses, the response to Haemophilus influenzae type b conjugate vaccine is impaired in preterm infants with very low gestational age, but comparable to that of term infants in preterms with higher gestational ages. After three doses the response to this vaccine is normal and unaffected by gestational age in preterms. Recombinant hepatitis b vaccine induces a reduced response in preterm infants even after three doses, and they may therefore need an extra dose of this vaccine. Studies of diphtheria-tetanus-whole-cell-pertussis vaccine and Haemophilus influenzae type b conjugate vaccine in preterm infants do not suggest that adverse effects occur more often or are more severe than those seen in term infants. The literature provides no background for postponement of immunizations in preterm infants.

Antibody response to Haemophilus influenzae type b capsular polysaccharide conjugated to tetanus toxoid in preterm infants

OBJECTIVE

To evaluate the antibody response to a Haemophilus influenzae type b capsular polysaccharide (HibCP) tetanus toxoid (TT) conjugate vaccine (HibCP-TT) in preterm infants.

SUBJECTS

Thirty-five healthy preterm infants with gestational ages (GA) from 27 to 36 weeks and birth weights from 920 to 2550 g. Controls were 37 term infants.

METHODS

All infants were immunized with HibCP-TT at 2, 4 and 12 months of age. Antibodies to HibCP and TT were determined at each immunization and 1 month after the second and third.

RESULTS

After two doses of HibCP-TT the preterm infants with GAs < or = 30 weeks (n = 8; mean GA, 29.5 weeks) had a significantly lower HibCP antibody response than the preterm infants with GAs > 30 weeks (n = 23; mean GA, 34.2 weeks) (P = 0.004), who for their part had a response not significantly different from that of the term infants. After the third dose there were no significant differences among the groups. The response to the TT part of the vaccine showed the same pattern.

CONCLUSION

Although the most immature infants may show an inadequate antibody response to the initial immunizations, many preterm infants can benefit from vaccination with HibCP-TT when starting immunization at the same chronologic age as term infants.

Stereoselective pharmacokinetics of methadone in chronic pain patients

Ten patients with chronic pain were randomized to an open, balanced, crossover study. Each patients received two different preparations of racemic methadone, i.e., tablets and intravenous infusion. The pharmacokinetic parameters of the R- and S-enantiomers of the racemate are reported. The analgesically active R-methadone has a significantly longer mean elimination half-life than the optical antipode S-methadone (t1/2 = 37.5 and 28.6 h, respectively). The mean total volume of distribution is 496.6 L for R-methadone and 289.1 L for S-methadone. Significant differences in the mean clearance between R- and S-methadone are seen (0.158 and 0.129 L/min, respectively). However, the lagtime after oral administration and the bioavailability did not show differences between the isomers. The data suggest that both enantiomers of methadone should be measured if correlations between pharmacodynamics and kinetics are made due to the stereoselective differences in half-life, total volume of distribution, and clearance.

[Use of blood products in Denmark in 1993. Regional differences and comparison with other Scandinavian and European countries]

In Denmark approximately 396,000 units of blood were collected during 1993 from among approximately 270,000 voluntary non-renumerated blood donors corresponding to about 76 donations per 100 inhabitants. Almost all units (approx. 99%) were fractionated into blood components in the blood banks. Approximately 16,000 erythrocyte units were rejected due to technical errors or quality control, while around 37,000 erythrocyte units were discarded from stock. Only 190 units were transfused as whole blood. In all 327,108 SAG-M erythrocyte suspensions, 70,971 thrombocyte concentrates, 50,161 units of fresh frozen plasma, FFP, and approximately 1700 kg albumin, 100% were transfused, corresponding to 63, 14 and 10 units and 340 g per 1000 inhabitants. When compared to other Scandinavian and European countries, Denmark has a high consumption of erythrocyte components, FFP and albumin for transfusion. The reason why cannot be clarified by available data, but it is not unlikely that Denmark has a more liberal transfusion policy than the other countries. There are considerable differences within Denmark as regards the clinical use of blood products. Counties/regions with university hospitals and regional and/or national functions tend to have a relatively high consumption. However, no information exists on consumption related to demographic parameters or related to hospitals, departments or diagnoses.

Adherence of chewing gum to dental restorative materials

PURPOSE

To describe a method whereby chewing gum tackiness can be measured.

MATERIALS AND METHODS

The chewing gum used for the experiment was V6 (Freshmint). Paladur denture base material, Silux Plus, P-50 and Heliomolar resin composites and Luxalloy amalgam were used. Squared specimens (15 x 15 x 2 mm) composed of the polymerized materials tested or set amalgam were made with a mold. As gold specimen, a gold-plated brass specimen was used, having the same dimension as specified above. A tooth enamel specimen (5 x 5 mm) was made out of flat ground human enamel from an incisor. All specimens were stored for more than 7 days in water before use, and wet ground on paper No 320 immediately before testing. The adhesion was measured by a balance equipped with a recorder and a bottom attachment, to which a chain was mounted. The end of the chain was attached to a quadratic brass plate, to which one of the above described specimen was glued by cyanoacrylate. Another brass plate, with an attached specimen of the same material, was mounted in a small vise in such way that the two specimens were parallel with and facing each other. A motor drive enabled parallel removal of the two plates from each other. The gum was chewed approximately 1 second between bites and for various periods of time. It was then pressed between the two parallel squares (mentioned above) of restorative materials or enamel, reaching a final distance of 1 mm between the plates and occupying the entire space between the plates. The study was carried out at 36 degrees C, and the two plates were wetted with fresh saliva or water immediately before placement of the chewing gum. Excess liquid was removed after the wetting, leaving a thin film. The maximal force during parallel removal of the two plates from each other was recorded. The measurements were performed eight times in each group, and the mean adhesion per surface area and SD was expressed as mN/mm(2). The measurements were repeated for some of the groups. The significance of differences between each group was tested by Newman-Keul's Multiple Range Test at a 5% level of significance.

RESULTS

Adherence of chewing gum to dental restorative materials and enamel was found to decrease as follows: denture base material > resin composites = silver amalgam > gold > human enamel. The adhesion was dependent on gum base and not on the sweetening additives and reached a maximum after about 2 minutes' chewing.

Characterization of the antibody response to a Haemophilus influenzae type b conjugate vaccine in children with recurrent lower respiratory tract infection

Children with recurrent lower respiratory tract infection (RLRI) may respond poorly to polysaccharide antigens. To examine how such children respond to a polysaccharide coupled to a protein carrier, we immunized 15 children with RLRI aged 8-69 months and 15 carefully age-matched healthy controls once with a Haemophilus influenzae type b (Hib) conjugate vaccine. Total IgG subclasses, total antipolysaccharide Hib antibodies, and antipolysaccharide Hib antibodies of IgM, IgG, IgA, and IgG1-4 specificity were determined by ELISA. There were no significant differences between the two groups in any single total IgG subclass, but total IgG measured as the sum of all four subclasses was significantly lower in the children with RLRI than in the controls (P = 0.036). Before vaccination, the children with RLRI had significantly less IgG antipolysaccharide Hib antibody than the controls (P = 0.005), whereas 1 month later they had significantly more IgM antibody (P = 0.038). No other significant differences were found between the groups before or after immunization with respect to antipolysaccharide Hib antibodies. Since naturally occurring IgG antibodies are thought to be acquired partly as a consequence of antigenic stimulation on mucosal surfaces, we hypothesize that the low level of specific IgG found before immunization, as well as the low total IgG in the children with RLRI, may reflect an impaired ability to prime through mucosal surfaces. This is supported by our finding of an increased IgM response to Hib conjugate vaccine in these children, since this isotype predominates in the primary immune response, i.e., in the absence of immunologic memory.(ABSTRACT TRUNCATED AT 250 WORDS)

The mu1, mu2, delta, kappa opioid receptor binding profiles of methadone stereoisomers and morphine

The binding affinities of racemic methadone and its optical isomers R-methadone and S-methadone were evaluated for the opioid receptors mu1, mu2, delta and kappa, in comparison with that of morphine. The analgesic R-methadone had a 10-fold higher affinity for mu1 receptors than S-methadone (IC50 3.0 nM and 26.4 nM, respectively). At the mu2 receptor, the IC50 value of R-methadone was 6.9 nM and 88 nM for S-methadone, respectively. As expected, R-methadone had twice the affinity for mu1 and mu2 receptors than the racemate. All of the compounds tested had low affinity for the delta and kappa receptors. This result suggests that S-methadone does not essentially contribute to opioid effect of racemic methadone. R-methadone has a receptor binding profile which resembles that of morphine.

Enantioselective high-performance liquid chromatographic method for the determination of methadone in serum using an AGP and a CN column as chiral and analytical column, respectively

A simple and sensitive HPLC method with ultraviolet absorption detection at 200 nm is described for the determination of methadone enantiomers in human serum, using dextropropoxyphene as an internal standard and organic solvent extraction. Separation was performed on two serially coupled columns, CN and Chiral AGP, with a mobile phase consisting of acetonitrile, dimethylocytlamine and phosphate buffer. Using 1.0 ml of serum, 5 nmol/1 of each enantiomer could be determined with an acceptable precision. No interactions from several drugs were observed. The method has been successfully used in a pharmacokinetic study. More than 2500 serum samples have been separated on the same AGP column with acceptable selectivity and resolution.

[Vaccination of splenectomized children. Antibody response to Haemophilus influenzae type b conjugate vaccine]

Twenty splenectomized children and adolescents aged four to 18 years were immunized once with a Haemophilus influenzae type b (Hib) polysaccharide tetanus toxoid conjugate vaccine. Prior to vaccination, ten of 20 patients had anticapsular antibodies below what could be considered the minimum protective level in the splenectomized (0.6 microgram per ml), whereas all obtained high antibody levels after vaccination. In addition, one infant with congenital asplenia was vaccinated at two, four, and six months of age, and was shown to respond well after the second and third injections, obtaining serum antibody concentrations of 0.84 and 10.7 microgram per ml respectively. Because asplenic individuals have an increased risk of invasive Hib infection, these data suggest that vaccination of such individuals against Hib may be justified.

Opposite effects of actively and passively acquired immunity to the carrier on responses of human infants to a Haemophilus influenzae type b conjugate vaccine

Vaccination of infants with Haemophilus influenzae type b (Hib) capsular polysaccharide (HibCP) coupled to carrier proteins has proven protective against invasive Hib diseases in several trials. However, insufficient immunogenicity has been noted in certain populations. Therefore, studies analyzing factors influencing the antibody response to conjugate vaccines are needed. In this study, the response to HibCP coupled to tetanus toxoid (TT) was examined in relation to (i) priming with or coadministration of the carrier protein and (ii) the levels of passively acquired maternal TT antibodies. One hundred forty-four infants were vaccinated with HibCP-TT at 5 and 6 months. They were randomized into three groups that received TT as part of a diphtheria-tetanus-polio vaccine at either 6 and 7 months (group A), 5 and 6 months (group B), or 4 and 5 months (group C). Maternally acquired TT antibodies inhibited the anti-HibCP response to the first HibCP-TT dose in groups A and B (r = -0.5 and -0.4, respectively; P < 0.005). In these groups, infants with prevaccination anti-TT levels above the median failed to reach the defined long-term protective level of HibCP antibodies (1 microgram/ml) more often than infants with low prevaccination levels after the first (P = 0.0001) and the second (P = 0.01) doses of HibCP-TT. In contrast, active priming with TT at 4 months resulted in a threefold-higher median level of anti-HibCP (group C; 1.34 micrograms/ml) than in the unprimed group (group A; 0.40 microgram/ml) after the first dose of HibCP-TT (P = 0.01). Coadministration of TT had no enhancing effect (group B; 0.58 microgram/ml). No significant differences between the median anti-HibCP levels were seen after the second HibCP-TT dose (6.72, 9.63, and 11.44 micrograms/ml in groups A, B, and C, respectively; P = 0.25).

[Finger tip injuries. A comparative study of silver sulfadiazine and fucidin gauze]

Eighty-eight superficial finger-tip lesions were randomized after thorough cleaning to either silver sulphadiazine treatment of Fucidin fusidic acid gauze. In the silver sulphadiazine group the wounds were covered with a non-sterile PVC gloce and redressed at least every third day; in the other group Fucidin gauze was applied and a tubigauze dressing was left in situ for ten days, after which a new dressing was applied. All patients were treated until healed and followed for at least six months after injury. Patients in the silver sulphadiazine group required shorter time for healing and shorter sick leave. The treatment is recommended because of the easy procedure and the good results.

General surgery in patients aged 80 years and older

This study reviews 594 surgical admissions, of patients aged 80 years and older, to departments of general surgery during 1 year. Half of the patients were admitted as emergencies and 60 per cent underwent surgery. The operative mortality rate was 8 per cent and the overall mortality rate for all admissions 9 per cent. The number of complications and the mortality rate after surgery increased in emergency cases and in patients with coexisting disease. Of all admissions, 72 per cent were uncomplicated and in 70 per cent patients could be discharged directly home; such patients do not generally take up beds and are discharged as soon as medical care is no longer indicated. The number of admissions of patients over 80 years of age will increase by about 30 per cent during this decade and, unless additional resources are provided to meet this challenge, new standards must be considered for the distribution of resources and of indications for surgery in both young and old.

Relation between enzyme-linked immunosorbent assay and radioimmunoassay for detection of antibodies to the capsular polysaccharide of Haemophilus influenzae type b

The measurement of antibodies to the capsular polysaccharide (PRP) of Haemophilus influenzae type b (Hib) is important because vaccines inducing such antibodies are now available. We developed and evaluated an enzyme-linked immunosorbent assay (ELISA) for detection of these antibodies based on direct coating of the plates with tyraminated PRP. The assay fulfilled the requirements for parallel line assays; it was sensitive, specific, and reproducible with a coefficient of variation between days of 19%. Results from the ELISA were compared with results from radioimmunoassay and a correlation coefficient of 0.93 was found. Results obtained by the two methods were proportional and the relation was independent of the antibody level. The relation between them was also unaffected by the contribution of different antibody isotypes, indicating that these were measured to the same extent by both methods. ELISA employing direct coating of the plates with tyraminated PRP represents a useful alternative for detection of antibodies when studying immunogenicity of Hib vaccines.

Antibody response to a Haemophilus influenzae type b polysaccharide tetanus toxoid conjugate vaccine in splenectomized children and adolescents

20 children and adolescents 4-18 years old and splenectomized for various reasons (spherocytosis (n = 6), idiopathic thrombocytopenia (n = 8), other (n = 6)) were immunized once with a Haemophilus influenzae type b (Hib) polysaccharide tetanus toxoid conjugate vaccine. Prior to vaccination 10/20 patients had anticapsular antibodies below what could be considered the minimum protective level in splenectomized (0.6 micrograms/ml), whereas all obtained high antibody levels after vaccination. In addition 1 infant with congenital asplenia was vaccinated at 2,4 and 6 months of age, and was shown to respond well after the second and third injection with serum antibody concentrations of 0.84 and 10.7 micrograms/ml respectively. Because asplenic individuals have an increased risk of invasive Hib infection, these data suggest that vaccination of such individuals against Hib may be justified.

Stereospecific gas chromatographic method for determination of methadone in serum

rac-Methadone is used clinically for the chronic maintenance treatment of heroin addiction and for the relief of pain. As the pharmacological activity of methadone is due primarily to the (-)-(R)-enantiomer, stereospecific measurements of methadone serum concentrations in methadone-treated patients are expected to be more relevant for clinical studies than earlier described total drug measurements. This study describes a stereospecific gas chromatographic (GC) method for the determination of methadone in serum. The extracted methadone was derivatizised with (-)-menthyl chloroformate. The diastereometric derivatives were analysed by GC on a capillary column and detected with a nitrogen-phosphorus detector. The resolution factor obtained for the methadone enantiomers was 1.1 with a relatively short time of analysis (30 min). By analysing the pure (-)-(R)-enantiomer, no racemization was seen during the analysis. The lower limit of quantitation was 75 nmol/l for each enantiomer. Measurements of the ratio between (-)-(R)- and (+)-(S)-methadone concentrations in serum from five methadone-treated patients showed interindividual differences (range 0.5-1.1). The patient results correlated well with those from another GC method measuring total methadone.