Timing and dosage of intrapartum prophylactic penicillin for preventing early-onset group B streptococcal disease: assessing maternal and umbilical cord blood concentration.

OBJECTIVE: Timing of administration of antibiotics and concentrations in maternal blood and the umbilical cord blood are important prerequisites for optimal intrapartum antibiotic prophylaxis (IAP) of neonatal early-onset group B streptococcus (GBS) disease. This cohort study aimed to explore penicillin concentrations in mothers and infants at birth in relation to time elapsed from administration to delivery and to the minimal inhibitory concentration (MIC) for GBS. MAIN OUTCOME MEASURES: Penicillin G concentrations in maternal and umbilical cord blood in relation to time and dose from administration to time of delivery. RESULTS: In 44 mother-infant dyads, median maternal penicillin G concentration was 0.2 mg/L (IQR 0-0.8 mg/L; range 0-1.6 mg/L). Median infant penicillin G concentration was 1.2 mg/L (IQR 0.5-5.0 mg/L; range 0-12.7 mg/L). In all infants (N=38) born less than 4 hours after the latest IAP administration, penicillin G concentrations far exceeded MIC (0.125 mg/L), even after short time intervals between IAP administration and birth. The highest plasma concentrations were reached in umbilical cord blood within 1 hour from IAP administration to birth.For 44 mother-infant dyads, maternal concentrations were very low compared with their infants'; particularly, very high concentrations were seen in the 20 infants with only one dose of IAP. CONCLUSION: High concentrations of penicillin G were found in umbilical cord blood of infants born less than 4 hours after IAP administration, well above the MIC for GBS.

Effect of lipid-based nutrient supplements on micronutrient status and hemoglobin among children with stunting: secondary analysis of a randomized controlled trial in Uganda.

BACKGROUND: Micronutrient deficiencies and anemia are widespread among children with stunting. OBJECTIVES: We assessed the effects of lipid-based nutrient supplements (LNS) containing milk protein (MP) and/or whey permeate (WP) on micronutrient status and hemoglobin (Hb) among children with stunting. METHODS: This was a secondary analysis of a randomized controlled trial. Children aged 12-59 mo with stunting were randomly assigned to LNS (100 g/d) with milk or soy protein and WP or maltodextrin for 12 wk, or no supplement. Hb, serum ferritin (S-FE), serum soluble transferrin receptor (S-TfR), plasma cobalamin (P-Cob), plasma methylmalonic acid (P-MMA), plasma folate (P-Fol), and serum retinol-binding protein (S-RBP) were measured at inclusion and at 12 wk. Data were analyzed using linear and logistic mixed-effects models. RESULTS: Among 750 children, with mean age ± SD of 32 ± 11.7 mo, 45% (n = 338) were female and 98% (n = 736) completed follow-up. LNS, compared with no supplementation, resulted in 43% [95% confidence interval (CI): 28, 60] greater increase in S-FE corrected for inflammation (S-FEci), 2.4 (95% CI: 1.2, 3.5) mg/L greater decline in S-TfR, 138 (95% CI: 111, 164) pmol/L greater increase in P-Cob, 33% (95% CI: 27, 39) reduction in P-MMA, and 8.5 (95% CI: 6.6, 10.3) nmol/L greater increase in P-Fol. There was no effect of LNS on S-RBP. Lactation modified the effect of LNS on markers of cobalamin status, reflecting improved status among nonbreastfed and no effects among breastfed children. LNS increased Hb by 3.8 (95% CI: 1.7, 6.0) g/L and reduced the odds of anemia by 55% (odds ratio: 0.45, 95% CI: 0.29, 0.70). MP compared with soy protein increased S-FEci by 14% (95% CI: 3, 26). CONCLUSIONS: LNS supplementation increases Hb and improves iron, cobalamin, and folate status, but not vitamin A status among children with stunting. LNS should be considered for children with stunting. This trial was registered at ISRCTN as 13093195.

Micronutrient Status and Other Correlates of Hemoglobin among Children with Stunting: A Cross-Sectional Study in Uganda.

In low-income countries, undernutrition and infections play a major role in childhood anemia. Stunted children may be at particular risk of anemia. In a cross-sectional study nested in a nutrition trial among 12-59-month-old stunted children in eastern Uganda, we measured hemoglobin (Hb) and markers of iron, cobalamin, folate and vitamin A status. We assessed low micronutrient status, socio-demography, stunting severity, inflammation and malaria as correlates of Hb and anemia using linear and logistic regression analyses, respectively. Of 750 stunted children, the mean ± SD age was 32.0 ± 11.7 months and 55% (n = 412) were male. The mean Hb was 104 ± 15 g/L and 65% had anemia, Hb < 110 g/L. In a multivariable model with age, sex and inflammation, the following were associated with lower Hb: serum ferritin < 12 µg/L (-5.6 g/L, 95% CI: -8.6; -2.6), transferrin receptors > 8.3 mg/L (-6.2 g/L, 95% CI: -8.4; -4.0), plasma folate <20 nmol/L (-4.6 g/L, 95% CI: -8.1;-1.1), cobalamin < 222 pmol/L (-3.0 g/L, 95% CI: -5.4; -0.7) and serum retinol-binding protein < 0.7 µmol/L (-2.0 g/L, 95% CI: -4.1; 0.2). In addition, severe stunting, inflammation and malaria were negative correlates. Anemia is common among stunted children in eastern Uganda; micronutrient deficiencies, inflammation and malaria are associated with low Hb.

Correlates of Iron, Cobalamin, Folate, and Vitamin A Status among Stunted Children: A Cross-Sectional Study in Uganda.

Micronutrient deficiencies and stunting are prevalent. We assessed correlates of iron, cobalamin, folate, and vitamin A biomarkers in a cross-sectional study of stunted children aged 12-59 months in eastern Uganda. The biomarkers measured were serum ferritin (S-FE), soluble transferrin receptor (S-TfR), retinol binding protein (S-RBP), plasma cobalamin (P-Cob), methylmalonic acid (P-MMA), and folate (P-Fol). Using linear regression, we assessed socio-demography, stunting severity, malaria rapid test, and inflammation as correlates of micronutrient biomarkers. Of the 750 children, the mean (SD) age was 32.0 (11.7) months, and 45% were girls. Iron stores were depleted (inflammation-corrected S-FE < 12 µg/L) in 43%, and 62% had tissue iron deficiency (S-TfR > 8.3 mg/L). P-Cob was low (<148 pmol/L) and marginal (148-221 pmol/L) in 3% and 20%, and 16% had high P-MMA (>0.75 µmol/L). Inflammation-corrected S-RBP was low (<0.7 µmol/L) in 21% and P-Fol (<14 nmol/L) in 1%. Age 24-59 months was associated with higher S-FE and P-Fol and lower S-TfR. Breastfeeding beyond infancy was associated with lower iron status and cobalamin status, and malaria was associated with lower cobalamin status and tissue iron deficiency (higher S-TfR) despite iron sequestration in stores (higher S-FE). In conclusion, stunted children have iron, cobalamin, and vitamin A deficiencies. Interventions addressing stunting should target co-existing micronutrient deficiencies.

Transplacental Transport of Artificial Sweeteners.

The prevalence of obesity is increasing, and the origins of obesity and metabolic dysfunction may be traced back to fetal life. Currently, overweight pregnant women are advised to substitute sugar-sweetened beverages with diet drinks containing artificial sweeteners. Recent evidence suggests that the consumption of artificial sweeteners during pregnancy increases the risk of obesity in the child, but the mechanism is unknown. We hypothesized the transportation of artificial sweeteners across the placenta into the fetal circulation and the amniotic fluid. We included 19 pregnant women who were given an oral dose of acesulfame, cyclamate, saccharin, and sucralose immediately before a planned caesarean section. Nine women were included as controls, and they refrained from an intake of artificial sweeteners. The maternal and fetal blood and amniotic fluid were collected during the caesarean section, and concentrations of artificial sweeteners were measured using mass spectrometry. We found a linear relationship between the fetal plasma concentrations of artificial sweeteners and the maternal plasma concentrations, with adjusted coefficients of 0.49 (95% CI: 0.28-0.70) for acesulfame, 0.72 (95% CI: 0.48-0.95) for cyclamate, 0.51 (95% CI: 0.38-0.67) for saccharin, and 0.44 (95% CI: 0.33-0.55) for sucralose. We found no linear relationship between amniotic fluid and fetal plasma concentrations, but there were positive ratios for all four sweeteners. In conclusion, the four sweeteners investigated all crossed the placenta and were present in the fetal circulation and amniotic fluid.

Reference intervals and stability of haptocorrin and holotranscobalamin in Danish children and elderly.

BACKGROUND: Haptocorrin (HC) and holotranscobalamin (holoTC) carry vitamin B12 (B12) in the circulation and can be useful biomarkers for evaluating B12 status. The concentration of both proteins depends on age, but data on reference intervals for children and the elderly are sparse. Similarly, not much is known about the effect of preanalytical factors. METHODS: HC plasma samples from healthy elderly > 65 years (n = 124) were analysed, and both HC and holoTC were analysed in paediatric serum samples ≤ 18 years (n = 400). Furthermore, we investigated assay precision and stability. RESULTS: HC and holoTC were effected by age. We established reference intervals for HC: 2-10 years, 369-1237 pmol/L; 11-18 years, 314-1128 pmol/L; 65-82 years, 242-680 pmol/L and for holoTC: 2-10 years, 46-206 pmol/L; 11-18 years, 30-178 pmol/L. Analytical coefficients of variations of 6.0-6.8% and 7.9-15.7% were found for HC and holoTC, respectively. HC were affected when stored at room temperature and by freeze/thaw. HoloTC was stable at room temperature and after delayed centrifugation. CONCLUSION: We present novel 95% age-related reference limits for HC and HoloTC in children, and for HC both in children and elderly. Moreover, we found HoloTC to be fairly stable when stored, whereas HC was more vulnerable to preanalytical factors.

Short-term biological variation of plasma uracil in a Caucasian healthy population.

OBJECTIVES: Plasma uracil is a new biomarker to assess the activity of dihydropyrimidine dehydrogenase before cancer treatment with fluoropyrimidine drugs. Knowledge on the biological variation of plasma uracil is important to assess the applicability of plasma uracil as a biomarker of drug tolerance and efficacy. METHODS: A total of 33 apparently healthy individuals were submitted to sequential blood draws for three days. On the second day, blood draws were performed every third hour for 12 h. Plasma uracil was quantified by LC-MS/MS. The within-subject (CVI) and between-subject (CVG) biological variation estimates were calculated using linear mixed-effects models. RESULTS: The overall median value of plasma uracil was 10.6 ng/mL (range 5.6-23.1 ng/mL). The CVI and CVG were 13.5 and 22.1%, respectively. Plasma uracil remained stable during the day, and there was no day-to-day variation observed. No differences in biological variation components were found between sex and no correlation to age was found. Four samples were calculated to be required to estimate the homeostatic set-point ±15% with 95% confidence. CONCLUSIONS: Plasma uracil is subject to tight homeostatic regulation without semidiurnal and day-to-day variation, however between-subject variation exists. This emphasizes plasma uracil as a well-suited biomarker for evaluation of dihydropyrimidine dehydrogenase activity, but four samples are required to establish the homeostatic set-point in a patient.

Automated Interlaboratory Comparison of Therapeutic Drug Monitoring Data and Its Use for Evaluation of Published Therapeutic Reference Ranges.

Therapeutic drug monitoring is a tool for optimising the pharmacological treatment of diseases where the therapeutic effect is difficult to measure or monitor. Therapeutic reference ranges and dose-effect relation are the main requirements for this drug titration tool. Defining and updating therapeutic reference ranges are difficult, and there is no standardised method for the calculation and clinical qualification of these. The study presents a basic model for validating and selecting routine laboratory data. The programmed algorithm was applied on data sets of antidepressants and antipsychotics from three public hospitals in Denmark. Therapeutic analytical ranges were compared with the published therapeutic reference ranges by the Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie (AGNP) and in additional literature. For most of the drugs, the calculated therapeutic analytical ranges showed good concordance between the laboratories and to published therapeutic reference ranges. The exceptions were flupentixol, haloperidol, paroxetine, perphenazine, and venlafaxine + o-desmethyl-venlafaxine (total plasma concentration), where the range was considerably higher for the laboratory data, while the calculated range of desipramine, sertraline, ziprasidone, and zuclopenthixol was considerably lower. In most cases, we identified additional literature supporting our data, highlighting the need of a critical re-examination of current therapeutic reference ranges in Denmark. An automated approach can aid in the evaluation of current and future therapeutic reference ranges by providing additional information based on big data from multiple laboratories.

Plasma concentration of orally administered amoxicillin and clindamycin in patients receiving haemodialysis.

OBJECTIVES: In the randomized controlled trial PANTHEM, the prophylactic effect of oral amoxicillin or clindamycin is investigated in patients receiving chronic haemodialysis (HD). However, data on plasma concentrations of these antibiotics during HD are sparse. This study aims to determine if the plasma concentration of amoxicillin and clindamycin is sufficient during HD after oral administration of amoxicillin and clindamycin at three different time intervals prior to the HD procedure. METHODS: Adult patients receiving chronic HD were investigated twice with an interval of at least 7 days starting with either a tablet of 500/125 mg amoxicillin/clavulanic acid or a tablet of 600 mg clindamycin. Patients were randomized to take the antibiotics either 30, 60 or 120 min prior to the HD procedure. Plasma antibiotic concentrations were measured at start, midway and at the end of HD. A lower threshold was set at 2.0 mg/L for amoxicillin and at 1.0 mg/L for clindamycin. In addition, a population pharmacokinetic (PK) analysis was performed, assessing PTA. RESULTS: In the amoxicillin cohort (n = 37), 84% of patients and 95% of all plasma amoxicillin concentrations were above or at the threshold throughout the dialysis procedure. In the clindamycin cohort (n = 33), all concentrations were above the threshold throughout the dialysis procedure. Further, in all patients, the mean plasma concentration of both amoxicillin and clindamycin across the HD period was well above the threshold. Finally, the PK model predicted a high PTA in the majority of patients. DISCUSSION: In patients on chronic HD, oral administration of amoxicillin/clavulanic acid (500/125 mg) or clindamycin (600 mg) within 30-120 min prior to HD leads to a sufficient prophylactic plasma concentration across the HD period.

Instability of uracil in whole blood might affect cancer treatment with fluoropyrimidines.

BACKGROUND AND AIMS: Measurement of plasma uracil is used before cancer treatment with fluoropyrimidines to determine if patients tolerate a full dose. Incorrect preanalytical handling may cause falsely elevated concentration and result in suboptimal cancer treatment. We aimed to examine the stability of uracil in whole blood stored at room temperature (RT) and the effect of centrifugation temperature. MATERIALS AND METHODS: EDTA tubes (6x4 mL) were collected from 25 healthy volunteers. Five samples were stored 0, 1.5, 2, 3, and 4 h at RT and centrifuged at 4 °C. The sixth sample was centrifuged at RT after 1.5 h. Uracil was measured using an in-house LC-MS/MS method. RESULTS: Storage of whole blood at RT followed by centrifugation at 4 °C caused a rapid increase in uracil concentration. Already after 1.5 h, the mean change (20.5 % (95 % CI: 11.9-29.2 %)) exceeded the maximum permissible difference. Centrifugation at RT instead of 4 °C after 1.5 h resulted in a smaller increase (7.0 % (95 % CI: 0.7-13.4 %)), although not statistically significant (p = 0.0527). CONCLUSION: Uracil was unstable in samples processed according to current recommendations. Our data indicates better stability when centrifugation is performed at RT compared with 4 °C but further research into this is necessary.

Development of a Sensitive ELISA for Gastric Intrinsic Factor and Detection of Intrinsic Factor Immunoreactivity in Human Serum.

Gastric Intrinsic Factor (IF) is produced by the parietal cells of the stomach and secreted into the gastrointestinal tract where it ensures the active absorption of vitamin B12. We hypothesized that a small amount of IF ends up in the circulation and can be measured in serum. The aim of this study was to develop an assay for measuring human IF and to demonstrate its presence in serum. We designed a sensitive ELISA for measurement of human IF using a commercial monoclonal antibody and an in-house polyclonal antibody as capture and detecting antibody, respectively. Imprecision, accuracy, and linearity of the assay were examined. We established a reference interval based on serum samples from 240 healthy donors, and explored the daily IF fluctuations in 20 healthy subjects. Employing a prototype IF ELISA and size exclusion chromatography experiments, we demonstrated the presence of IF in human serum. In its final design, the IF ELISA has a measurement range of 0.2 to 50 pmol/L. The intra-assay and total imprecision were 7.9% and 15%, respectively. The 95% reference interval (18-65 years) was 1.7-11.6 pmol/L. No diurnal fluctuation or notable sex differences were observed. Our results suggest that the assay is capable of detecting and quantifying human IF in the circulation and may prove useful in the characterization of patients with impaired IF production.

Artificial Sweeteners in Breast Milk: A Clinical Investigation with a Kinetic Perspective.

Artificial sweeteners (ASs) are calorie-free chemical substances used instead of sugar to sweeten foods and drinks. Pregnant women with obesity or diabetes are often recommended to substitute sugary products with ASs to prevent an increase in body weight. However, some recent controversy surrounding ASs relates to concerns about the risk of obesity caused by a variety of metabolic changes, both in the mother and the offspring. This study addressed these concerns and investigated the biodistribution of ASs in plasma and breast milk of lactating women to clarify whether ASs can transfer from mother to offspring through breast milk. We recruited 49 lactating women who were provided with a beverage containing four different ASs (acesulfame-potassium, saccharin, cyclamate, and sucralose). Blood and breast milk samples were collected before and up to six hours after consumption. The women were categorized: BMI < 25 (n = 20), BMI > 27 (n = 21) and type 1 diabetes (n = 8). We found that all four ASs were present in maternal plasma and breast milk. The time-to-peak was 30−120 min in plasma and 240−300 min in breast milk. Area under the curve (AUC) ratios in breast milk were 88.9% for acesulfame-potassium, 38.9% for saccharin, and 1.9% for cyclamate. We observed no differences in ASs distributions between the groups.

New methods for quantification of amoxicillin and clindamycin in human plasma using HPLC with UV detection.

OBJECTIVES: We aimed to develop simple and rapid HPLC methods for determination of amoxicillin and clindamycin in human plasma. METHODS: Plasma samples were pretreated by direct deproteinization with acetonitrile and the analytical separation took place on a reverse phase Poroshell 120 EC-C18 column (2.7 µm, 2.1 × 100 mm) with a gradient of acetonitrile. UV detection at 229 nm for amoxicillin and 204 nm for clindamycin was used for determination of the antibiotics in plasma. RESULTS: The calibration curves were linear over the concentration ranges of 1-100 mg/L for amoxicillin and 1-15 mg/L for clindamycin with a correlation coefficient of ≥0.98. Intra-assay precisions were all ≤15% and the accuracies were within ±15%. The limit of quantification (LOQ) was found to be 0.5 mg/L for amoxicillin and 1 mg/L for clindamycin with inter-assay imprecision coefficient of variances (CVs) of 18.7% and 15.6%, respectively. The present HPLC methods were successfully applied on spike-in samples and on plasma samples collected 4-6 and 3.5-5.5 h after oral antibiotic administration of 500 mg of amoxicillin and 600 mg of clindamycin, respectively. CONCLUSIONS: We have developed HPLC methods with UV detection for quantification of amoxicillin and clindamycin in human plasma. The methods are fast, simple and suitable for use in routine settings and clinical studies.

Development and validation of an LC-MS/MS method for the quantification of artificial sweeteners in human matrices.

Artificial sweeteners are widely used as substitutes for sugar. The sweeteners are generally considered safe, however their whereabouts during pregnancy and lactation and the effect on child development are poorly explored. There is a need for new tools to measure these substances during pregnancy and lactation. Here, we describe the development and validation of a sensitive liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of acesulfame, cyclamate, saccharin and sucralose in human plasma, umbilical cord blood, amniotic fluid and breast milk. The samples were prepared by protein precipitation and separated on a Luna Omega Polar C18 column (2.1 × 50 mm, 1.6 µm). Electrospray ionization in negative mode and multiple reaction monitoring were used to monitor the ion transitions. The validated concentration ranges were from 1 to 500 ng/ml (10-500 ng/ml for sucralose). Interassay precisions were all ≤15% and the accuracies were within ±15%. Stability, linearity, dilution integrity, carryover and recovery were also examined and satisfied the validation criteria. Finally, this analytical method was successfully applied on spiked samples of plasma, umbilical cord blood, amniotic fluid and breast milk, proving its suitability for use in clinical studies on artificial sweeteners, including during pregnancy and lactation.

Reference intervals for plasma vitamin B12 and plasma/serum methylmalonic acid in Danish children, adults and elderly.

BACKGROUND: Plasma/serum vitamin B12 (B12) is often used to screen for B12 deficiency complemented with analysis of methylmalonic acid (MMA) in case of low B12. The concentration of both analytes likely depends on age, and we, therefore, aimed at establishing 95% age-adjusted reference intervals (RIs) for plasma B12 and serum/plasma MMA in the Danish population. METHODS: We collected and analysed blood samples from healthy children, adults, and elderly individuals and extracted routine clinical B12 and MMA results to establish RIs. We also evaluated the association between matching B12 and MMA results. RESULTS: We suggest the following RIs for plasma B12 and plasma/serum MMA, respectively. 0-<1 year: 180-1400 pmol/L, 0.10-1.25 µmol/L; 1-<11 years: 260-1200 pmol/L, 0.10-0.30 µmol/L; 12-<18 years: 200-800 pmol/L, 0.10-0.35 µmol/L; 18-<65 years: 200-600 pmol/L, 0.10-0.40 µmol/L; 65 + years: 200-600 pmol/L, 0.12-0.46 µmol/L. Finally, the proportion of patients with elevated MMA differed between age groups independently of B12 and was highest in children. CONCLUSION: We propose new age-adjusted RIs for B12 and MMA and suggest that age-dependent cut-off values should be implemented if plasma B12 is used to screen for B12 deficiency.

Effects of Prolonged Whey Protein Supplementation and Resistance Training on Biomarkers of Vitamin B12 Status: A 1-Year Randomized Intervention in Healthy Older Adults (the CALM Study).

We investigated the effect of long-term whey supplementation on biomarkers of B12 status in healthy older adults subjected to different schemes of supplements and exercise. The total study population examined at baseline consisted of 167 healthy older adults (age ≥ 65 year) who were randomized to 1-y intervention with two daily supplements of (1) whey protein (3.1 µg B12/day) (WHEY-ALL), (2) collagen (1.3 µg B12/day) (COLL), or (3) maltodextrin (0.3 µg B12/day) (CARB). WHEY-ALL was comprised of three groups, who performed heavy resistance training (HRTW), light resistance training (LITW), or no training (WHEY). Dietary intake was assessed through 3-d dietary records. For the longitudinal part of the study, we included only the participants (n = 110), who met the criteria of ≥ 50% compliance to the nutritional intervention and ≥ 66% and ≥ 75% compliance to the heavy and light training, respectively. Fasting blood samples collected at baseline and 12 months and non-fasting samples collected at 6 and 18 months were examined for methylmalonic acid, B12 and holotranscobalamin. At baseline, the study population (n = 167) had an overall adequate dietary B12 intake of median (range) 5.3 (0.7-65) µg/day and median B12 biomarker values within reference intervals. The whey intervention (WHEY-ALL) caused an increase in B12 (P < 0.0001) and holotranscobalamin (P < 0.0001). In addition, methylmalonic acid decreased in the LITW group (P = 0.04). No change in B12 biomarkers was observed during the intervention with collagen or carbohydrate, and the training schedules induced no changes. In conclusion, longer-term daily whey intake increased plasma B12 and holotranscobalamin in older individuals. No effect of intervention with collagen or carbohydrate or different training regimes was observed. Interestingly, the biomarkers of B12 status appeared to be affected by fasting vs. non-fasting conditions during sample collection.

Effects of rifampicin on moxifloxacin concentrations in porcine cervical spine: a randomized microdialysis study.

BACKGROUND: Pyogenic spondylodiscitis remains a therapeutic challenge, as demonstrated by divergent treatment guidelines. The combination of moxifloxacin and rifampicin may be an attractive treatment option for cases caused by staphylococci; however, previous studies have reported a reduction in plasma concentrations of moxifloxacin when coadministered with rifampicin. The magnitude of this reduction in spinal tissues is not known. OBJECTIVES: To investigate the effect of rifampicin on moxifloxacin tissue concentrations in vertebral cancellous bone, the intervertebral disc and subcutaneous adipose tissue under steady-state conditions using microdialysis in a porcine model. METHODS: Twenty female pigs were randomized into two groups of 10 pigs. Group A received 400 mg of moxifloxacin orally once daily for 3 days preoperatively. Group B received 400 mg of moxifloxacin orally once daily for 3 days preoperatively combined with 450 mg of rifampicin twice daily for 7 days preoperatively. Measurements were obtained from plasma, vertebral cancellous bone, the intervertebral disc and subcutaneous adipose tissue for 24 h. Microdialysis was applied for sampling in solid tissues. RESULTS: Coadministration of moxifloxacin and rifampicin demonstrated a reduction of free moxifloxacin concentrations in spinal tissues. Cmax and AUC0-24 in all tissue compartments decreased in the ranges of 66%-79% and 65%-76%, respectively. CONCLUSIONS: Using microdialysis, we demonstrated a significant reduction of moxifloxacin Cmax and AUC0-24 in the spinal tissues when coadministered with rifampicin.

Cyano-B12 or Whey Powder with Endogenous Hydroxo-B12 for Supplementation in B12 Deficient Lactovegetarians.

Lactovegetarians (n = 35) with low vitamin B12 (B12) status were intervened for eight weeks capsules containing cyano-B12 (CN-B12), (2 × 2.8 µg/day), or equivalent doses of endogenous B12 (mainly hydroxo-B12 (HO-B12)) in whey powder. Blood samples were examined at baseline, every second week during the intervention, and two weeks post-intervention. The groups did not differ at baseline in [global median (min/max)] plasma B12 [112(61/185)] pmol/L, holotranscobalamin [20(4/99)] pmol/L, folate [13(11/16)], the metabolites total homocysteine [18(9/52)] µmol/L and methylmalonic acid [0.90(0.28/2.5)] µmol/L, and the combined indicator of B12 status (4cB12) [-1.7(-3.0/-0.33)]. Both supplements caused significant effects, though none of the biomarkers returned to normal values. Total plasma B12 showed a higher increase in the capsule group compared to the whey powder group (p = 0.02). However, the increase of plasma holotranscobalamin (p = 0.06) and the lowering of the metabolites (p > 0.07) were alike in both groups. Thereby, the high total plasma B12 in the capsule group was not mirrored in enhanced B12 metabolism, possibly because the B12 surplus was mainly accumulated on an "inert" carrier haptocorrin, considered to be of marginal importance for tissue delivery of B12. In conclusion, we demonstrate that administration of whey powder (HO-B12) or capsules (CN-B12) equivalent to 5.6 µg of B12 daily for eight weeks similarly improves B12 status but does not normalize it. We document that the results for plasma B12 should be interpreted with caution following administration of CN-B12, since the change is disproportionately high compared to the responses of complementary biomarkers.