Pedagogy, Partnership, and Collaboration: A Longitudinal, Empirical Study of Serious Educational Gameplay in Secondary Biology Classrooms

The use of serious educational games has the potential to increase student learning outcomes in science education by providing students with opportunities to explore phenomena in ways that vary from traditional instruction; yet, empirical research to support this assertion is limited. This study aimed to explore deeply what learning gains were associated with the use of three serious educational games (SEGs) created for use in secondary biology classrooms that partner teachers implemented during a 2-week curriculum unit. This longitudinal, mixed method study includes a control year, in which we examined how six highly qualified teachers taught students (n = 407) a 2-week curriculum unit addressing cellular biology without the SEGs, followed by 2 years in which the teachers integrated the SEGs into the curriculum unit with students (n =871). Data were collected from multiple sources, including a validated content pre- and post-test measure, embedded gameplay data, participant observation, teacher interviews, and focus groups. Quantitative findings showed significant learning gains associated with students who experienced the game condition during year 2, when compared with the control condition. During the replication year (year 3), learning gains increased again, compared with year two. Although the SEGs did not change between years 2 and 3, teachers were provided real-time access to students' performance during gameplay. Thematic analysis of observation notes, teacher interviews, and student performance in-game identified four affordances teachers identified related to the use of serious educational games in their classrooms and the extended partnership model employed. Implications for researchers and game designers are discussed.

African-Caribbean Cancer Consortium Scientific and Training Conference 2017

The sixth International African-Caribbean Cancer Consortium (AC3) Conference was held 6-9 October 2017 in Miami, Florida, U.S.A. The conference was open to all researchers, trainees, clinical and public health professionals, and community members, and served as an international hub for the United States, the Caribbean, and Africa. Sessions included AC3 collaboration meetings, cancer surveillance and research skills training workshops, and a community cancer prevention conference.

Docosahexaenoic acid supplementation in lactating women increases breast milk and plasma docosahexaenoic acid concentrations and alters infant omega 6:3 fatty acid ratio

This study investigated the effects of docosahexaenoic acid (DHA) supplementation on the fatty acid composition of breast milk and plasma concentrations in lactating women and their infants. Eighty-nine lactating women 4-6 weeks post-partum received placebo, 200 mg or 400 mg DHA for 6 weeks with usual diets. Breast milk fatty acids and maternal plasma fatty acids were measured at the beginning and end of the study and infant plasma at the end of the study. Breast milk and maternal plasma DHA were significantly greater with 200 mg and 400 mg DHA compared with placebo (50% and 123% breast milk p<0.05; 71% and 101% plasma, p<0.0001), respectively. Infant plasma omega 6:3 and arachidonic acid (AA):DHA were significantly greater in the placebo group compared to both supplement groups (67% and 106%; 71% and 116%, respectively, p<0.05). DHA supplementation impacts infant fatty acids important for brain development and breast milk fatty acid composition.

Longitudinal growth and health outcomes in nutritionally at-risk children who received long-term nutritional intervention

BACKGROUND

The benefits of short-term oral nutritional supplementation (ONS) in undernourished children are well-established. The benefits of long-term ONS in promoting longitudinal growth and health in children who are at risk of undernutrition have not been reported previously.

METHODS

In this 48-week prospective, single-arm, multicentre trial, 200 Filipino children aged 3-4 years with weight-for-height percentiles from 5th to 25th (WHO Child Growth Standards) were enrolled. Parents received dietary counselling at baseline, and at weeks 4 and 8. Two servings of ONS (450 mL) were consumed daily, providing 450 kcal, 13.5 g protein and micronutrients. Weight, height, dietary intake using 24-h dietary recalls, and physical activity and appetite using the visual analogue scales were assessed at baseline and weeks 4, 8, 16, 24, 32, 40 and 48. The number of sick days for acute illnesses was collected over the study period.

RESULTS

At baseline, mean age was 41.2 months with 50% being male. Weight-for-height percentiles showed the greatest increase in the first 4 weeks (12.1 and 12.8 percentiles, respectively, P < 0.0001) and remained significantly higher than baseline (P < 0.0001) but were relatively stable from week 4 onwards. Height-for-age percentiles increased steadily over time and became significantly higher than baseline from week 24 onwards (P < 0.0001). Appetite and physical activity scores at all post-baseline visits improved from baseline (P < 0.0001), and a reduction in the number of sick days from week 16 onwards was also observed (P < 0.0001). Higher parental education level, being male and higher baseline weight-for-height percentiles were significantly associated with higher ponderal and linear growth over time in repeated measures analysis of covariance.

CONCLUSIONS

Intervention consisting of initial dietary counselling and continued ONS helped sustain normal growth after a catch-up growth in nutritionally at-risk children.

Antarctic soft-bottom benthos in oligotrophic and eutrophic environments

The benthos of the east and west sides of McMurdo Sound, Antarctica, is characterized by dramatically different infaunal assemblages. The eutrophic East Sound has higher infaunal densities than almost any other benthic assemblage in the world. In contrast, the oligotrophic West Sound, bathed by currents from beneath the Ross Ice Shelf, has patterns of mobile epifauna and low infauna density similar to bathyl deep-sea communities.

Drug related deaths amongst Glasgow city hostel dwellers

The problems of homelessness and drug misuse are every day issues encountered in today's society. Over the past 2 years the number of hostel residents overdosing within their rooms in the city of Glasgow was shown to increase. Approximately three-quarters of deaths involved heroin, of which 56% also involved at least one benzodiazepine. This paper demonstrates a dearth in the literature relating to drug misuse amongst the homeless population, highlighting an area in need of address by the appropriate authorities.

Drugs in oral fluid

As part of the European project, Impaired Motorists, Methods of Roadside Testing and Assessment for Licensing, otherwise known as IMMORTAL (Deliverable R4.2), the University of Glasgow was required to analyse 1396 oral fluid samples, collected from drivers, for a wide range of drugs. A previously described method to include 49 drugs and metabolites was used. To include cannabis in the study a separate extraction method was required because of interferences caused by the collection device. The study group included drivers who were stopped at random and participation was entirely voluntary. The results showed that out of the 1396 samples tested, 16.8% were positive for at least one drug. In the majority of positive cases (85%), monodrug use was found and the most commonly detected drug was 3,4-methylenedioxymethamphetamine. This study showed that a significant number of the driving population are positive for at least one drug.

Drugs in oral fluid Part I. Validation of an analytical procedure for licit and illicit drugs in oral fluid

A qualitative and quantitative analytical method was developed and validated for the determination of 49 licit and illicit drugs in oral fluid. Small oral fluid samples, volume 1mL, were collected from volunteers using a modified Omni-Sal device and the analytes were extracted from an oral fluid/buffer mixture using a single Bond Elut Certify solid phase extraction cartridge. Liquid chromatography-tandem mass spectrometry (LC-MS-MS) and gas chromatography-repetitive full scan mass spectrometry (GC-MS) were used in parallel to analyze the extracts for the targeted drugs. Extracts were analyzed by GC-MS in their underivatized form and as their pentafluoropropionyl derivatives. Deuterated internal standards were used for quantification of drugs of abuse by LC-MS-MS to minimize matrix effects. Methadone-d(9) and tumoxetine were used as the internal standards for quantification of non-derivatized and derivatized analytes respectively by GC-MS. Linearity was demonstrated over the range 5-200 ng/mL and limits of detection were less than 4 ng/mL for each drug analyzed. The method demonstrated acceptable recoveries for most of the analytes and good intra- and inter-day precision. Acquisition of data by repetitive full scan GC-MS allows the addition of further analytes to the target menu.

Drug related deaths in the Strathclyde region of Scotland, 1995-1998

The misuse of drugs, both illicit and prescribed has increased dramatically in the west of Scotland over the last few decades. Consequently, the number of drug related deaths has risen as a direct result. Since, discrepancies exist between data collected by the Department of Forensic Medicine and Science, University of Glasgow and official statistics, this project, was funded to investigate all known drug related deaths that occurred within the Strathclyde region of Scotland in an effort to improve the accuracy of statistics and the dissemination of information pertaining to them. Changes in medical treatment, legislation and patterns of drug taking were noted and the effects of these on the year-by-year death tolls evaluated.

The role of dihydrocodeine in causing death among drug users in the west of Scotland

There has been a wealth of information relating to the role of methadone in fatalities over the past decade. However, a dearth exists in the literature of deaths involving dihydrocodeine, a substitute that is being increasingly prescribed by general practitioners for drug harm reduction purposes. Over the past five years in the Strathclyde region of Scotland there has been an increase in the number of drug related deaths involving dihydrocodeine with the largest increase occurring in the latter two years. This in combination with a general acceptance for this drug as a substitute for methadone amongst general practitioners highlights its potential abuse factor which is addressed in this paper. As the number of methadone deaths in relation to the total number of accidental drug related deaths per annum decrease, those related to dihydrocodeine are shown to be increasing.

Effect of the universal base 3-nitropyrrole on the selectivity of neighboring natural bases

[structure: see text] The effect of the universal base 3-nitropyrrole on the pairing selectivity of neighboring nucleosides has been determined for every combination of complementary and neighboring nucleosides. In a subset of cases the discriminatory ability of the neighboring nucleoside for its Watson-Crick complement is compromised. The results have implications for the hybridization of oligonucleotides that contain 3-nitropyrrole and suggest caution in the use of oligonucleotides that contain other universal bases.

The use of vitreous humor as an alternative to whole blood for the analysis of benzodiazepines

In postmortem drug analysis, the most commonly used sample matrix is whole blood. However, postmortem changes can denature this matrix, resulting in a loss or degradation of drugs, thus biasing analytical findings. Vitreous humor is thought to be less affected by these changes and should, therefore, have the potential to provide a more reliable estimation of antemortem drug concentrations. To assess the usefulness of vitreous humor for the analysis of benzodiazepine drugs, vitreous humor and whole blood were obtained postmortem in 27 cases. Three benzodiazepine drugs were investigated-temazepam, diazepam, and desmethyldiazepam. For temazepam and diazepam, some correlation was found between the matrices (R2 = 0.789 and 0.724, respectively). However, for desmethyldiazepam, no correlation was observed (R2 = 0.068). Regression analysis on plots of vitreous humor versus blood concentrations produced gradients of less than 1.0 showing that, in general, levels in blood are higher than the corresponding levels in vitreous humor.

The Neurospora crassa genome: cosmid libraries sorted by chromosome

A Neurospora crassa cosmid library of 12,000 clones (at least nine genome equivalents) has been created using an improved cosmid vector pLorist6Xh, which contains a bacteriophage lambda origin of replication for low-copy-number replication in bacteria and the hygromycin phosphotransferase marker for direct selection in fungi. The electrophoretic karyotype of the seven chromosomes comprising the 42.9-Mb N. crassa genome was resolved using two translocation strains. Using gel-purified chromosomal DNAs as probes against the new cosmid library and the commonly used medium-copy-number pMOcosX N. crassa cosmid library in two independent screenings, the cosmids were assigned to chromosomes. Assignments of cosmids to linkage groups on the basis of the genetic map vs. the electrophoretic karyotype are 93 +/- 3% concordant. The size of each chromosome-specific subcollection of cosmids was found to be linearly proportional to the size of the particular chromosome. Sequencing of an entire cosmid containing the qa gene cluster indicated a gene density of 1 gene per 4 kbp; by extrapolation, 11,000 genes would be expected to be present in the N. crassa genome. By hybridizing 79 nonoverlapping cosmids with an average insert size of 34 kbp against cDNA arrays, the density of previously characterized expressed sequence tags (ESTs) was found to be slightly <1 per cosmid (i.e., 1 per 40 kbp), and most cosmids, on average, contained an identified N. crassa gene sequence as a starting point for gene identification.

Heterologous expression and characterization of a "Pseudomature" form of taxadiene synthase involved in paclitaxel (Taxol) biosynthesis and evaluation of a potential intermediate and inhibitors of the multistep diterpene cyclization reaction

The diterpene cyclase taxadiene synthase from yew (Taxus) species transforms geranylgeranyl diphosphate to taxa-4(5),11(12)-diene as the first committed step in the biosynthesis of the anti-cancer drug Taxol. Taxadiene synthase is translated as a preprotein bearing an N-terminal targeting sequence for localization to and processing in the plastids. Overexpression of the full-length preprotein in Escherichia coli and purification are compromised by host codon usage, inclusion body formation, and association with host chaperones, and the preprotein is catalytically impaired. Since the transit peptide-mature enzyme cleavage site could not be determined directly, a series of N-terminally truncated enzymes was created by expression of the corresponding cDNAs from a suitable vector, and each was purified and kinetically evaluated. Deletion of up to 79 residues yielded functional protein; however, deletion of 93 or more amino acids resulted in complete elimination of activity, implying a structural or catalytic role for the amino terminus. The pseudomature form of taxadiene synthase having 60 amino acids deleted from the preprotein was found to be superior with respect to level of expression, ease of purification, solubility, stability, and catalytic activity with kinetics comparable to the native enzyme. In addition to the major product, taxa-4(5),11(12)-diene (94%), this enzyme produces a small amount of the isomeric taxa-4(20), 11(12)-diene ( approximately 5%), and a product tentatively identified as verticillene ( approximately 1%). Isotopically sensitive branching experiments utilizing (4R)-[4-(2)H(1)]geranylgeranyl diphosphate confirmed that the two taxadiene isomers, and a third (taxa-3(4),11(12)-diene), are derived from the same intermediate taxenyl C4-carbocation. These results, along with the failure of the enzyme to utilize 2, 7-cyclogeranylgeranyl diphosphate as an alternate substrate, indicate that the reaction proceeds by initial ionization of the diphosphate ester and macrocyclization to the verticillyl intermediate, followed by a secondary cyclization to the taxenyl cation and deprotonation (i.e., formation of the A-ring prior to B/C-ring closure). Two potential mechanism-based inhibitors were tested with recombinant taxadiene synthase but neither provided time-dependent inactivation nor afforded more than modest competitive inhibition.

Drug-related deaths among recently released prisoners in the Strathclyde Region of Scotland

Drug abuse and its consequences are everyday problems encountered globally, and Scotland is no exception. During a study of drug-related deaths in the Strathclyde region of Scotland it was noted that known drug users who had recently been released from prison were at high risk of dying from a drug overdose. The majority of deaths occurred within one week of the release date and polydrug use was prevalent. Morphine was the most frequently encountered drug and this was found in combination with benzodiazepines in a significant number of cases. This paper highlights the dangers of resuming drug consumption following a period of abstinence.

The application of supercritical fluid extraction to cocaine and its metabolites in blood and urine

Supercritical fluid extraction (SFE) is emerging as a valuable analytical technique for use as an alternative to conventional solid-phase (SPE) and liquid-liquid extraction techniques. It is a relatively new technique based on the use of supercritical fluids for the isolation of analytes from various matrices and is attracting great interest because of the increasing need for a simple, rapid, environmentally friendly, automated, and selective extraction method. A new method using SFE procedures for the extraction of cocaine and its major metabolites, benzoylecgonine and ecgonine methyl ester, from whole blood and urine was developed. This study has shown that cocaine and its metabolites can be successfully extracted from blood and urine using SFE techniques. Levels measured using SFE have shown analyte recovery better than 70% for cocaine, better than 40% for benzoylecgonine, and better than 85% for ecognine methyl ester from whole blood and urine. Good run-to-run reproducibility was observed between each extraction with limits of detection and quantitation of 1 ng and 10 ng based on 200 microL of blood and urine. A comparison between SPE and developed SFE techniques was investigated to observe if a correlation existed between the two methods. Studies proved that a correlation did exist between the two methods for spiked blood and urine samples with comparative results. This paper details a procedure for the extraction of cocaine and its metabolites from blood and urine.

Hair analysis: self-reported use of "speed" and "ecstasy" compared with laboratory findings

Drug use histories were collected from 100 subjects recruited from the "dance scene" in and around Glasgow, Scotland. In addition, each subject donated a hair sample which was analyzed by gas chromatography/mass spectrometry (GC/MS) for amphetamine (AP), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MD MA) and 3,4-methylenedioxyethylamphetamine (MDEA). The hair samples were analyzed in two 6 cm segments or in full, ranging from 1.5 to 12 cm depending on the length of the hair. Approximately 10 mg of hair was ground to a fine powder before treatment with beta-glucuronidase/aryl sulfatase. A solid-phase extraction procedure was carried out followed by derivatization with pentafluoropropionic anhydride (PFPA). All extracts were analyzed by gas chromatography/mass spectrometry (GC/MS). Of the 139 segments analyzed, 77 (52.5%) were positive for at least one of the five amphetamines. The drug concentrations found in the hair were compared with the self-reported drug histories. A concordance of greater than 50% was found between the self-report data and levels detected in hair. However, no correlation was found between the reported number of "ecstasy" tablets consumed and the drug levels detected in hair. An increase in the average drug levels measured was observed from low to high use (number of "ecstasy" tablets/month). A large number of false negatives and a low number of false positives were observed.

The use of supercritical fluid extraction for the determination of amphetamines in hair

A laboratory study interested in the analysis of human hair for drugs-of-abuse was conducted to determine if drugs could be detected and quantified from hair. Supercritical fluid extraction (SFE) techniques followed by GC-MS analysis were applied to extract amphetamines from hair. The group of amphetamines included methylenedioxyamphetamine (MDA), methylenedioxymetamphetamine (MDMA), methylenedioxyethylamphetamine (MDEA) and internal standard mephentermine (MP). To validate information on amphetamine use in hair, powdered hair samples free from drugs were collected and soaked in a known amphetamine standard solution. Authentic fortified case hair samples taken from known drug users known to have consumed amphetamines were also analyzed for amphetamine. Results from this study show that amphetamine use can be detected in spiked and authentic fortified human hair using SFE techniques for qualitative and quantitative reproducible results.

A confidential enquiry into methadone-related deaths

AIM

To assess the acceptability and usefulness of the "confidential enquiry" process in examining methadone-related deaths.

DESIGN

An audit of patient care.

SETTING

Glasgow, Scotland, UK (population 915,000) Participants. All doctors who, in the final 14 days of the patient's life, had attended a patient who suffered a methadone-related death.

MEASUREMENTS

The medical care of each case was assessed by peer review and the results of these assessments returned to the responsible clinician(s).

FINDINGS

(1) The audit cycle was completed in 32 of the 34 reported cases (94%). (2) Twenty-eight of 33 doctors (85%) found the audit to be helpful. (3) As a result of the enquiry, the majority of doctors whose patient management had attracted criticism intended to amend their practice. (4) Shortcomings in clinical care were identified in 18 cases (56%) and problems in the organization of services in 22 (69%).

CONCLUSIONS

(1) The model of audit piloted here was found to be highly acceptable to participants. (2) The episodes of substandard care that were uncovered provided useful opportunities to improve the future management of patients who were being prescribed methadone.

Role of drugs and alcohol in impaired drivers and fatally injured drivers in the Strathclyde police region of Scotland, 1995-1998

During the 4-year study period, 1995-1998, the Department of Forensic Medicine and Science, University of Glasgow received a total of 752 biological samples from drivers suspected of driving under the influence of drink and/or drugs in the Strathclyde region of Scotland. The majority of samples were blood and had been primarily obtained from males. Drugs were detected in 68 and 90% of blood and urine samples, respectively. Toxicological analyses revealed that cannabis was the most frequently encountered illegal drug which was detected in 39% of all drug positive blood samples. Benzodiazepines were detected in the majority of drug positive samples with 82% containing at least one member of this group. Polydrug use was prevalent, with the average number of drugs detected per sample increasing from 2.0 in 1995 to 3.1 in 1998. For comparison, the results of toxicological analyses from 151 fatally injured drivers are described. Although the majority of samples tested negative for the presence of drugs and alcohol, drugs were found to be present in 19% and alcohol was detected in 33%. As the majority of drugs had been prescribed or administered post-accident, this study shows that alcohol was the main causative factor conducive to fatal road traffic accidents.

A study of methadone in fatalities in the Strathclyde Region, 1991-1996

There was a substantial increase in the percent of drug screens testing positive for methadone between 1991 and 1996 in the Strathclyde region of Scotland. Seventy-nine per cent (n = 136) of these deaths were drug-related, involving methadone either alone or in combination with other drugs such as diazepam, temazepam, alcohol and morphine. The involvement of methadone in the majority of these fatalities was due to diversion of legitimate supply. This paper highlights the dangers of resuming methadone consumption following a period of abstinence or when taken in combination with other drugs.

Comparison of solid-phase extraction and supercritical fluid extraction for the analysis of morphine in whole blood

A comparative study of the quantitative determination of morphine in whole blood using solid-phase extraction (SPE) and supercritical fluid extraction (SFE) is described. Comparative studies were made of the two techniques for the extraction of morphine from authentic forensic blood specimens. Quantitative results indicate that morphine levels measured using SPE correspond well to morphine levels produced using SFE. The two techniques are therefore comparable, although SFE is faster and cleaner and extracts may be produced with higher analyte recoveries than with SPE. This paper presents a comparison of the two techniques and the morphine concentrations determined in blood.

Vitreous humor as an alternative sample to blood for the supercritical fluid extraction of morphine and 6-monoacetylmorphine

The use of vitreous humor as an alternative sample to blood was investigated for the detection of heroin abuse by quantifying levels of morphine and 6-monoacetylmorphine (6-MAM) in post-mortem samples. The levels achieved in each of the two toxicological specimens were compared on a case-to-case basis to determine if a correlation existed. A total of 20 positive morphine cases were examined. In general, the levels of morphine in blood were higher than in the corresponding vitreous humor samples, with some correlation existing. 6-MAM was found in 15 blood samples and 17 vitreous humor samples. Although no correlation was found between the levels of 6-MAM in blood and vitreous humor, the latter may still be used for verification of heroin abuse.

Improved solid-phase extraction of methadone and its two major metabolites from whole blood

A solid-phase extraction (SPE) method for the efficient extraction of methadone and its two major metabolites, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine and 2-ethyl-5-methyl-3,3-diphenyl-1-pyrroline, from whole blood is described. The procedure combines extraction on Isolute Confirm HCX mixed-mode SPE columns and gas chromatographic-mass spectrometric analysis with deuterated methadone as the internal standard. The optimum extraction conditions for all three analytes were determined using spiked whole blood. The developed method is easier and faster than current liquid-liquid extraction (LLE) procedures and produces cleaner extracts. Calibration curves were linear from 0 to 600 ng/mL (r2 > 0.99) with recoveries greater than 90% for all three analytes. The concentrations of methadone and its metabolites in postmortem blood were determined in fatal cases using the developed SPE method and were found to compare well with results obtained using LLE.

Stability of morphine and buprenorphine in whole blood

Delays between time of sampling and time of toxicological analysis are common, therefore the length of time that postmortem blood can be stored at various temperatures (e.g. 4 degrees, 25 degrees, -20 degrees C) was evaluated for the effect on the stability of morphine and buprenorphine from day one up to one year. Solid phase extraction and GC-MS were used for the isolation and quantification of the drugs. Morphine and buprenorphine were found to be very stable for up to 6 months under these storage conditions, where at least 85% and 77% of morphine and buprenorphine respectively, were recovered. The study showed that a reasonable amount of the drugs (not less than 70%) was still detectable after one year of storage regardless of the temperature when blood samples were stored in silanized glass vessels.

Exploiting unassigned codons in Micrococcus luteus for tRNA-based amino acid mutagenesis

An alternative to suppression of stop codons for the biosynthetic insertion of non-natural amino acids has been developed. Micrococcus luteus , a Gram-positive bacterium, is incapable of translating at least two codons. One of these unused codons was inserted in a gene to act as a nonsense site. An aminoacylated tRNA was synthesized which was complementary to this codon. The gene containing the missing codon was expressed in vitro in a M.luteus transcription/translation system. Read-through of the missing codon occurred only when the complementary tRNA was included. The results demonstrate that M.luteus can be used for incorporation of amino acids via synthetically prepared aminoacylated tRNAs. The use of a M. luteus translation system provides a method for incorporation of non-natural amino acids which avoids the use of stop codons.

Matrix multiplication with DNA

A DNA-based method for calculating the product of Boolean matrices or matrices containing positive, real numbers is presented. In the case of matrices containing real numbers, the manipulation of reaction conditions allows a quantitative calculation to be performed. The use of DNA to perform an analog calculation illustrates a new approach to computing with DNA.

Development of a supercritical fluid extraction method for the determination of temazepam in whole blood

A supercritical fluid extraction (SFE) procedure for the analysis of temazepam from whole blood was developed. Quantitative recoveries were obtained by high-performance liquid chromatography using prazepam as an internal standard and carefully monitoring the extraction temperature and pressure. The results were found to compare well with those obtained by solid-phase extraction techniques, but they also had the advantages of reduced solvent consumption and minimal sample handling. The application of this method to authentic forensic blood specimens showed the SFE method to be useful as an alternative procedure for the extraction of temazepam in the toxicology laboratory.

Stability of temazepam in blood

The stability of temazepam in blood under different storage temperatures was studied. The drug was found to be very stable over a twelve-month interval when stored at -20 degrees C with a recovery of 82%, while samples stored at 5 degrees C and 25 degrees C showed a significant decrease in their concentration with time. This information can assist the forensic toxicologist with the interpretation of results, particularly in cases where analysis has been delayed.

Pentalenene synthase. Purification, molecular cloning, sequencing, and high-level expression in Escherichia coli of a terpenoid cyclase from Streptomyces UC5319

Pentalenene synthase, which catalyzes the cyclization of farnesyl diphosphate (1) to the tricyclic sesquiterpene hydrocarbon pentalenene (2), was purified from Streptomyces UC5319. A 450-bp hybridization probe, generated by PCR amplification of genomic DNA using primers based on N-terminal and internal tryptic peptide sequence data for pentalenene synthase, was used to screen both plasmid and phage DNA libraries of Streptomyces genomic DNA, resulting in the isolation and sequencing of the complete pentalenene synthase gene. PCR was used to insert the pentalenene synthase gene into the T7 expression vector pLM1. Cloning of the resulting construct in the expression host Escherichia coli BL21 (DE3) gave transformants that expressed pentalenene synthase as greater than 10% of soluble protein. The recombinant enzyme has been purified, and initial physical and kinetic characterization has been performed. The recombinant enzyme appears to be identical in every respect with the native Streptomyces synthase and exhibits the following steady-state kinetic parameters: Km = 0.31 +/- 0.05 microM, kcat = 0.32 +/- s-1, KI(PPi) = 3.2 +/- 0.6 microM. Both enzymes have an absolute requirement of Mg2+ for catalysis and an optimum pH of 8.2-8.4. Both proteins have M(r) values of 41-42 kDa, as determined by SDS-PAGE.

Overproduction of soluble trichodiene synthase from Fusarium sporotrichioides in Escherichia coli

Trichodiene synthase is a sesquiterpene cyclase isolated from various fungal species which catalyzes the cyclization of farnesyl diphosphate (FPP) to trichodiene. The trichodiene synthase gene (Tox5) of Fusarium sporotrichioides has previously been cloned and expressed as 0.05-0.1% of total cell protein in Escherichia coli. We have used polymerase chain reaction to amplify the trichodiene coding sequence carried on the plasmid pTS56-1. The resulting DNA, carrying a BamHI restriction site and the T7 gene 10 ribosome binding site and translational spacer element immediately upstream of the ATG start codon as well as a HindIII site adjacent to the translational stop codon, was inserted into the corresponding sites of the expression vector pLM1. The latter vector carried the promoter and translational leader sequence from T7 gene 10 and the E. coli rmBT1T2 tandem transcription terminator. This construct was cloned into E. coli BL21 (DE3). The resulting transformants, when induced with isopropyl beta-D-thiogalactoside, produced trichodiene synthase as 20-30% of total soluble protein. The recombinant synthase, which could be purified five-fold to homogeneity by ammonium sulfate precipitation, ion-exchange chromatography on Q Sepharose, and gel filtration on Superose 12, was identical to native protein in steady-state kinetic parameters and mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and had the expected MENFP N-terminal sequence.

Terpenoid biosynthesis and the stereochemistry of enzyme-catalysed allylic addition-elimination reactions

Allylic addition-elimination reactions are widely used in the enzyme-catalysed formation of terpenoid metabolites. It has earlier been shown that the isoprenoid chain elongation reaction catalysed by farnesyl pyrophosphate synthase involving successive condensations of dimethylallyl pyrophosphate (DMAPP) and geranyl pyrophosphate (GPP) with isopentenyl pyrophosphate (IPP) corresponds to such an SE' reaction with net syn stereochemistry for the sequential electrophilic addition and proton elimination steps. Studies of the enzymic cyclization of farnesyl pyrophosphate (FPP) to pentalenene have now established the stereochemical course of two additional biological SE' reactions. Incubation of both (9R)- and (9S)-[9-3H,4,8-14]FPP with pentalenene synthase and analysis of the resulting labelled pentalenene has revealed that H-9re of FPP becomes H-8 of pentalenene, while H-9si undergoes net intramolecular transfer to the adjacent carbon, becoming H-1re (H-1 alpha) of pentalenene, as confirmed by subsequent experiments with [10-2H, 11-13C]FPP. These results correspond to net anti-stereochemistry in the intramolecular allylic addition-elimination reaction. The stereochemical course of a second SE' reaction has now been examined by analogous incubations of (4S,8S)-[4,8-3H,4,8-14C]FPP and (4R,8R)-[4,8-3H, 4.8-14C]FPP with pentalenene synthase. Determination of the distribution of label in the derived pentalenenes showed stereospecific loss of the original H-8si proton. Analysis of the plausible conformation of the presumed reaction intermediates revealed that the stereochemical course of the latter reaction cannot properly be described as either syn or anti, since cyclization and subsequent double bond formation require significant internal motions to allow proper overlap of the scissile C-H bond with the developing carbocation.

Radioreceptor assay and radioimmunoassay of triazolam in urine samples from racing greyhounds

Two complimentary assay techniques were used to determine triazolam levels in greyhound urine samples following a single oral dose. The results from the trials were statistically compared. The relative non-specificity of the benzodiazepine antibody used in radioimmunoassay caused a significant difference in teh two sets of results. This was independent of hydrolysis.

2-(Fluoromethyl)-3-phytyl-1,4-naphthoquinone and its 2,3-epoxide. Inhibition of vitamin K epoxide reductase

2-(Fluoromethyl)-3-phytyl-1,4-naphthoquinone (7) was synthesized from the known compound 2-bromo-3-methyl-1,4-dimethoxynaphthalene by N-bromosuccinimide bromination of the 3-methyl group, conversion to the corresponding 3-fluoromethyl compound with silver fluoride, attachment of the 3-phytyl substitutent via the lithium diaryl cuprate and phytyl bromide, and then silver oxide oxidation to 7. Epoxidation with basic hydrogen peroxide gave the corresponding 2,3-oxide (1) in a very low yield. Compound 1 was not a time-dependent inhibitor of beef liver microsomal vitamin K epoxide reductase, but it was a competitive, reversible inhibitor. It was not possible to determine if 1 was a substrate for the enzyme because the expected product of reduction, namely 7, rapidly decomposed under the assay conditions.

Rapid extraction of oxazepam from greyhound urine for high performance liquid chromatography analysis

A rapid and efficient procedure is described for the extraction and analysis of oxazepam, the major urinary metabolite of diazepam in greyhounds. Urine was extracted by passing through a bonded silica column (Bond Elut) following enzyme hydrolysis. The adsorbed drug was eluted and then detected and measured by high performance liquid chromatography (HPLC). Recoveries were in excess of 85% at 50 ng/ml concentrations. Detection was possible up to 30 h after a single oral dose of diazepam (5 mg).

The measurement and interpretation of morphine in blood

A method for the determination of morphine is post-mortem blood by HPLC with electrochemical detection is described. Blood morphine levels in post-mortem cases are reported and the importance of these in causing death is discussed. These post-mortem levels are compared further with morphine levels in the blood of patients receiving morphine as an analgesic.

Fatal outcome following inhalation of Tipp-Ex

Recent measures to combat glue sniffing have led to a decrease in the availability of toluene-based glues. As a result, abuse of other more accessible solvents appears to have increased. Of particular concern are the halogenated hydrocarbons which are more likely to cause fatal cardiac arrhythmias than toluene. We wish to report three cases presenting within a period of six months where death occurred following inhalation of Tipp-Ex, a seemingly innocuous preparation of 1,1,1-trichloroethane which is widely available in offices and schools.

Sedation in intensive care: morphine and renal function

Intravenous morphine infusions have been administered to 12 critically-ill patients during controlled ventilation. Acute oliguric renal failure was present in 4 patients, who were treated with a combination of haemofiltration and haemodialysis. Severity of physiological disturbance was assessed using a modified APACHE Score, level of sedation by a linear-analogue scale, and blood morphine levels by high-pressure liquid chromatography. Morphine clearance was impaired in renal failure, and was dependent on haemofiltration volumes; accumulation of morphine did not occur during this form of treatment. Conscious level was clearly more closely related to the degree of physiological disturbance than blood morphine levels; and for a given blood morphine level, depression of consciousness was more pronounced the greater the degree of physiological disturbance. Use of a physiological sickness score may help to clarify some of the factors influencing cerebral function during critical illness. Careful clinical monitoring of level of sedation is important in patients with oliguric renal failure receiving morphine, and haemofiltration appears to reduce the risk of morphine accumulation in these patients.

Gray whales and the structure of the Bering Sea benthos

The purpose of this study was to look at the effect of foraging by gray whales on the benthic community. The gray whale, the only mysticete whale which feeds mainly upon benthic organisms, relies on the amphipod crustacean assemblages of the northern Bering Sea and the Chukchi Sea for most of its annual food intake. Foraging whales leave identifiable depressions 0.6 to 3 m long in the bottom sediments in their wake. Patterns in the infaunal community composition appeared to be correlated with the size of the pit and by inference, the age of the pit. Large, deep pits were characterized by species considered early colonists of disturbed areas. Smaller, shallow depressions did not have elevated numbers of early colonists. Abundance of Ampelisca macrocephala, the dominant bottom organism and whale prey item, was depressed in all pits sampled.

Solvent encephalopathy

Nineteen children aged 8-14 years were admitted over a six-year period with an acute encephalopathy due to toluene intoxication. Seven had a history of euphoria and hallucinations. The remainder presented with coma (4), ataxia (3), convulsions (3), and behaviour disturbance with diplopia (2), A history of glue sniffing was elicited in 14, but in the remainder toluene assay confirmed the diagnosis. Thirteen children recovered completely; five still had psychological impairment and personality change on discharge from hospital but were lost to follow-up, and one has a persistent cerebellar ataxia one year after the acute episode, despite absence of further exposure. Toluene inhalation is an important cause of encephalopathy in children and may lead to permanent neurological damage. Diagnosis is most important if further damage due to continued abuse is to be prevented, and toluene assay is a valuable aid to diagnosis.