Ethylene glycol: Evidence of glucuronidationin vivoshown by analysis of clinical toxicology samples

In the search for improved laboratory methods for the diagnosis of ethylene glycol poisoning, the in vivo formation of a glucuronide metabolite of ethylene glycol was hypothesized. Chemically pure standards of the β‐O‐glucuronide of ethylene glycol (EG‐GLUC) and a deuterated analog (d₄‐EG‐GLUC) were synthesized. A high‐performance liquid chromatography and tandem mass spectrometry method for determination of EG‐GLUC in serum after ultrafiltration was validated. Inter‐assay precision (%RSD) was 3.9% to 15.1% and inter‐assay %bias was −2.8% to 12.2%. The measuring range was 2–100 μmol/L (0.48–24 mg/L). Specificity testing showed no endogenous amounts in routine clinical samples (n = 40). The method was used to analyze authentic, clinical serum samples (n = 31) from patients intoxicated with ethylene glycol. EG‐GLUC was quantified in 15 of these samples, with a mean concentration of 6.5 μmol/L (1.6 mg/L), ranging from 2.3 to 15.6 μmol/L (0.55 to 3.7 mg/L). In five samples, EG‐GLUC was detected below the limit of quantification (2 μmol/L) and it was below the limit of detection in 11 samples (1 μmol/L). Compared to the millimolar concentrations of ethylene glycol present in blood after intoxications and potentially available for conjugation, the concentrations of EG‐GLUC found in clinical serum samples are very low, but comparable to concentrations of ethyl glucuronide after medium dose ethanol intake. In theory, EG‐GLUC has a potential value as a biomarker for ethylene glycol intake, but the pharmacokinetic properties, in vivo/vitro stability and the biosynthetic pathways of EG‐GLUC must be further studied in a larger number of patients and other biological matrices.

Unequal evolutionary rates between annual and perennial lineages of checker mallows (Sidalcea, Malvaceae): evidence from 18S-26S rDNA internal and external transcribed spacers

Heterogeneous DNA substitution rates were found in the 18S-26S nuclear ribosomal DNA internal transcribed spacer (ITS) and external transcribed spacer (ETS) regions of Sidalcea (Malvaceae), a putatively young genus of annuals and perennials. The majority of comparisons revealed that the annual species had significantly higher molecular evolutionary rates than the perennials, whereas rates were consistently homogenous between obligate annual species. These findings led us to conclude that generation time or possibly another biological factor distinguishing annuals and perennials has influenced rates of molecular evolution in SIDALCEA: The congruence of relative-rate test results across both spacer regions reinforced the association between life history and rate of rDNA evolution across lineages of checker mallows. Evolutionary rate variation within perennials mainly involved three basally divergent lineages. The faster rate in one lineage, Sidalcea stipularis, compared with other perennials may be the result of genetic drift in the only known, small, population. The other two basally divergent lineages had slower evolutionary rates compared with the remaining perennials; possible explanations for these differences include rate-reducing effects of a suffrutescent (rather than herbaceous) habit and seed dormancy.

The relationship between clinical and MRI findings in patients with unilateral temporomandibular joint pain

BACKGROUND

With the advent of magnetic resonance imaging, or MRI, clinicians and researchers have sophisticated techniques by which to assess the anatomy of the temporomandibular joint, or TMJ. Imaging is indicated when the results will affect the patient's care beyond that which can be gained from a complete clinical assessment. One of the primary indications for treatment of patients with temporomandibular disorders, or TMDs, is jaw pain, including TMJ pain. Therefore, it is necessary to assess whether MRI-depicted TMJ findings are associated with TMJ pain. This study assessed the relationship between TMJ pain and clinical and MRI findings.

METHODS

Subjects consisted of 85 patients with unilateral jaw pain in the area of the TMJ. The contralateral, nonpainful TMJ served as the matched control. All patients underwent a complete stomatognathic examination that included palpation of both TMJs. No care was given and no anti-inflammatory medications were prescribed until bilateral MRIs were obtained within one week.

RESULTS

The authors found significant relationships between the side of reported jaw pain and the patient's report that palpation of the TMJ was painful and between the side of reported pain and the presence of MRI-detected effusions. The authors found no relationship between the side of reported pain and the presence of a disk displacement, or DD, or between the presence of effusions and DD on either side of the jaw.

CONCLUSION

Although MRI-depicted effusions of the TMJ were associated with reports of TMJ pain, there was a high level of false-positive and false-negative findings. The results indicate that palpation of the TMJ is more accurate than MRI-depicted effusions in identifying the TMJ as the source of pain for patients with unilateral jaw pain.

CLINICAL IMPLICATIONS

The results of this study suggest that palpation of the TMJ is superior to MRI in identifying the joint as the source of pain. Therefore, the most cost-effective and valid test to determine if the TMJ is a source of jaw pain is a complete clinical assessment.

Combined phylogenetic analysis in the Rubiaceae-Ixoroideae: morphology, nuclear and chloroplast DNA data

Parsimony analyses of morphology, restriction sites of the cpDNA, sequences from the nuclear, ribosomal internal transcribed spacer (ITS), and the chloroplast gene rbcL were performed to asses tribal and generic relationships in the subfamily Ixoroideae (Rubiaceae). The tribes Vanguerieae and Alberteae (Antirheoideae) are clearly part of Ixoroideae, as are some Cinchonoideae taxa. Pavetteae should exclude Ixora and allies, which should be recognized as the tribe Ixoreae. Heinsenia, representing Aulacocalyceae, is part of Gardenieae, as is Duperrea, a genus earlier placed in Pavetteae. Posoqueria and Bertiera and the taxa in the subtribe Diplosporinae should be excluded from Gardenieae. Bertiera and three Diplosporinae taxa are part of Coffeeae, while Cremaspora (Diplosporinae) is best housed in a tribe of its own, Cremasporeae. The mangrove genus Scyphiphora, recently placed in Diplosporinae, is closer to Ixoreae and tentatively included there. The combined analysis resulted in higher resolution compared to the separate analyses, exemplifying that combined analyses can remedy the incapability of one data set to resolve portions of a phylogeny. Twenty-four new rbcL sequences representing all five Ixoroideae tribes (sensu Robbrecht) are presented.

Validation of urine drug-of-abuse testing methods for ketobemidone using thin-layer chromatography and liquid chromatography-electrospray mass spectrometry

High-performance thin-layer chromatography (TLC) with visual detection (post-chromatographic derivatization) was used in screening for the drug ketobemidone in human urine samples. High-performance liquid chromatography with electrospray mass spectrometry (LC-ESI-MS) was used for final confirmation of the result. The clean-up was performed by mixed-mode solid-phase extraction, and nalorphine was used as internal standard. A screening cut-off for TLC was established at 0.2 microg/ml. The mean recovery for LC-MS was 91% (n=60) with coefficients of variation (C.V.) in the range of 7 to 16%. Qualifying fragment ions of ketobemidone (m/z 190, 201 and 230) were generated by up front collision-induced dissociation (CID) on a single quadrupole instrument. Relative ion intensities were within +/- 15% deviation compared with standards in the same batch. The limit of detection for LC-MS was 0.025 microg/ml. Positive clinical samples from drug abusers (n=10) had concentrations in the range 0.07 to 3.2 microg/ml, which could be determined by LC-MS without matrix interference. During screening of unknown clinical samples (n=27) the results from TLC was in agreement with LC-MS data. After acid hydrolysis of conjugates in clinical samples the analyte response of ketobemidone and norketobemidone was increased by a factor of approximately two and twelve, respectively. A qualitative GC-MS technique was demonstrated for the detection of the spasmolyticum A29 (N,N-dimethyl-4,4-diphenyl-3-buten-2-amine), which can be found in a preparation combined with ketobemidone (Ketogan).

Determination of 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid in urine using high-performance liquid chromatography and electrospray ionization mass spectrometry

High-performance liquid chromatography with electrospray ionization mass spectrometry was used to determine 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in urine. After basic hydrolysis of conjugates, the compound was extracted using SPEC-PLUS-3ML-C18 solid-phase extraction columns. A deuterium labelled internal standard (d3-THC-COOH) was added prior to hydrolysis. Separation was performed on a reversed-phase Zorbax Eclipse XDB-C8 analytical column (150x3.0 mm I.D.) using a gradient program from 60 to 80% acetonitrile (4 mM formic acid) at a flow-rate of 0.5 ml/min. The compounds were detected by single ion monitoring of m/z 345 and m/z 348 for the protonated molecules [THC-COOH+H]+ and [d3-THC-COOH+H]+, respectively. The precision and accuracy were tested on spiked urine samples in the range 2.5-125 ng/ml. The mean recovery was 95% (n = 58), coefficients of variations were 2.2-4.3% and the limit of detection 2 ng/ml. Diagnostic qualifying ions of THC-COOH (m/z 327 and m/z 299) and d3-THC-COOH (m/z 330) were generated using up-front collision-induced dissociation. The relative ion intensities in clinical samples (n = 21) were within +/-20% deviation compared with standards. Using this tolerance and the presence of the ions m/z 327 and m/z 299 at the correct retention times as the acceptance criteria for identification of THC-COOH positive samples, the limit of detection was 15 ng/ml. The LC-MS method complies with the current recommendations on drugs of abuse testing, in which mass spectrometric detection is emphasized.

Application of microautoradiography to the study of substrate uptake by filamentous microorganisms in activated sludge

Excessive growth of filamentous microorganisms in activated-sludge treatment plants is a major operational problem which causes poor settlement of activated sludge. An enhanced understanding of the factors controlling growth of different filamentous microorganisms is necessary in order to establish more successful control strategies. In the present study, the in situ substrate uptake was investigated by means of microautoradiography. It was demonstrated that the uptake of labeled organic substrates by the filamentous microorganisms, during short-term incubation, could be detected by microautoradiography. Viability and respiratory activity of the filaments were also detected by reduction of CTC (5-cyano-2,3-ditolyl tetrazolium chloride) and by incorporation of [(sup3)H]thymidine. Gram, Neisser, and fluorescence staining techniques were used for the localization and identification of the filaments. Activated-sludge samples from five wastewater treatment plants with bulking problems due to filamentous microorganisms were investigated. Microthrix parvicella, Nostocoida limicola, and Eikelboom's type 0041 and type 021N were investigated for their ability to take up organic substrates. A panel of six substrates, i.e., [(sup14)C]acetate, [(sup3)H]glucose, [(sup14)C]ethanol, [(sup3)H]glycine, [(sup3)H]leucine, and [(sup3)H]oleic acid, was tested. The uptake response was found to be very specific not only between the different filamentous types but also among filaments of the same type from different treatment plants. Interestingly, M. parvicella consistently took up only oleic acid among the tested substrates. It is concluded that microautoradiography is a useful method for investigation of in situ substrate uptake by filamentous microorganisms in activated sludge.

Acute effect of high-fat meals rich in either stearic or myristic acid on hemostatic factors in healthy young men

Suggestions have been made that saturated fatty acids with 12-18 carbon atoms, stearic acid (18:0) in particular, are prothrombogenic. These suggestions are based mainly on in vitro measurements. In the present study the effect of dietary fats high in stearic or myristic acid (14:0) on plasma triacylglycerol concentrations and key variables of blood aggregation (in vitro and in vivo), coagulation, and fibrinolysis was studied over 24 h in 10 healthy young men. For each dietary fat, two identical high-fat test meals were served: one in the morning (0 h) and one 8 h later, and blood samples were collected at 0, 2, 4, 6, 8, and 24 h. Both fats decreased platelet aggregation compared with fasting values. Stearic fat resulted in a tendency toward lower activity of plasminogen activator inhibitor 1 (PAI-1) than did myristic fat (P < 0.08). PAI-1 was also lower 24 h after consumption of either fat than initially (P < 0.05). Stearic fat, but not myristic fat, tended to cause some increase in factor VII coagulant activity and beta-thromboglobulin after 4 h. In conclusion, an acute prothrombotic effect of fats high in myristic and stearic acid was not confirmed.

Evaluation of the psychological profiles of patients with signs and symptoms of temporomandibular disorders

The psychologic profiles of 98 female patients with signs & symptoms of temporomandibular disorders are compared with those of a control group having no signs or symptoms of such disorders. Scores on the Crown Crisp Experimental Index indicate a significant difference in the profiles of somatization and hysteria.

Cholecystokinin in nucleus tractus solitarii modulates tonic and phasic gastric pressure

Local excitation of neurons at the site of termination of gastric vagal afferents in the nucleus tractus solitarii (NTS) alters gastric pressure. Microinjection of one putative satiety peptide bombesin into NTS increases pressure while substance P lowers it. Therefore, we sought to determine the effects of the microinjection of cholecystokinin octapeptide (CCK-8) from micropipettes placed stereotactically into the NTS of anesthetized rats with balloons placed in the gastric antrum to sense gastric pressure waves. Sulfated CCK-8, but not nonsulfated CCK-8, produced dose-dependent decreases of gastric pressure, transient blockade of phasic waves, and subsequent dysrhythmic phasic activity. The effects were specifically related to injections into NTS and did not occur with injections given intravenously, intracisternally, or into tissue adjacent to NTS. These results support a role for CCK-8 in central regulation of not only tonic gastric pressure but also phasic activity and gastric motility.