Increased detection of marijuana use with a 50 micrograms/L urine screening cutoff.
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Dronabinol↗
Biomedical subjects
J Irving
Publications and source records attributed to J Irving.
An altered repertoire of fos/jun (AP-1) at the onset of replicative senescence.
With multiple divisions in culture, normal diploid cells suffer a loss of growth potential that leads to replicative senescence and a finite replicative capacity. Using quantitative RT-PCR, we have monitored mRNA expression levels of c-fos, c-jun, JunB, c-myc, p53, H-ras, and histone H4 during the replicative senescence of human fibroblasts. The earliest and the largest changes in gene expression occurred in c-fos and junB at mid-senescence prior to the first slowing in cell growth rates. The basal level of c-fos mRNA decreased to one-ninth that of the early-passage levels, while junB declined to one-third and c-jun expression remained constant. The decline in the basal c-fos mRNA level in mid-senescence should lead to an increase in Jun/Jun AP-1 homodimers at the expense of Fos/Jun heterodimers and may trigger a cascade of further changes in c-myc, p53, and H-ras expression in late-passage senescent fibroblasts.
Base Sequence↗
Decline in histone H5 phosphorylation during erythroid senescence in chick embryos.
Previous studies have implicated histone H5 dephosphorylation as a causal factor in genetic inactivation and chromatin condensation during erythroid senescence in adult chickens. We show that histone H5 phosphorylation declines in two stages as various cohorts of erythroid cells senesce in chick embryos. The first decline occurs between 5 and 6 days and coincides with the senescence of primitive erythrocytes. The second decline in H5 phosphorylation occurs between 17 and 19 days of chicken development, when the definitive erythrocytes undergo senescence and chromatin condensation. These results point to a role for histone dephosphorylation during the programmed senescence of erythroid cells.
Animals↗
A phosphatase inhibitor enhances the DNase I sensitivity of active chromatin.
Although it is well-known that active domains of chromatin have elevated DNase I sensitivity, it can be difficult to observe preferential sensitivity in many cell types. We show that the DNase I sensitivity of active chromatin is enhanced some 10-fold by treating nuclei with the phosphatase inhibitor p-(chloromercuri)benzenesulfonic acid (CMBS) whereas DNase I sensitivity in inactive domains is only 3-fold higher. We further show that CMBS-enhanced DNase I sensitivity is associated with at least two histone modifications. First, the negatively charged CMBS molecule becomes covalently attached to the thiol groups on histone H3. Second, histone H2A phosphorylation is significantly elevated in treated nuclei. The phosphorylation data along with other results point to the possibility that H2A phosphorylation plays a role in enhancing preferential DNase I sensitivity. Whatever the mechanism, CMBS treatment of nuclei followed by DNase I digestion provides a novel and reproducible assay for probing the chromatin structure of active domains.
4-Chloromercuribenzenesulfonate↗
Relaxation distribution function of intracellular dielectric zones as an indicator of tumorous transition of living cells.
The response decay data of living cells subject to electric polarization is associated with their relaxation distribution function (RDF) and can be determined using the inverse Laplace transform method. A new polynomial, involving a series of associated Laguerre polynomials, has been used as the approximating function for evaluating the RDF, with the advantage of avoiding the usual arbitrary trial values of a particular parameter in the numerical computations. Some numerical examples are given, followed by an application to cervical tissue. It is found that the average relaxation time and the peak amplitude of the RDF exhibit higher values for tumorous cells than normal cells and might be used as parameters to differentiate them and their associated tissues.
Animals↗
Histologic and magnetic resonance imaging correlations in Kienböck's disease.
Nine patients had magnetic resonance imaging studies to aid in the diagnosis of wrist pain in the midcarpal region. Six had positive magnetic resonance imaging studies with a decrease in signal intensity from the area of the lunate, one had an occult ganglion, and two had negative studies. Among the six patients with a diagnosis of Kienböck's disease by magnetic resonance imaging, four patients had collapse of the lunate on plain radiographs, and the other two patients had normal wrist radiographs. Magnetic resonance imaging studies showed a substantial decrease in the signal intensity on T1- and T2-weighted images of the entire lunate in three patients, and three patients had focal areas of decreased signal intensity. All of the patients had a biopsy of the lunate at the time of surgery. The histology of the biopsies of the lunate appeared to correspond to the magnetic resonance imaging studies. Undecalcified bone specimens from the patients with Kienböck's disease showed marked osteonecrosis in three patients, focal areas of osteonecrosis in two patients, and alternating areas of osteonecrosis with dramatic areas of new bone formation in one patient. Although in four patients the diagnosis was obvious by plain radiographs, magnetic resonance imaging studies were essential in confirming the diagnosis in two patients and were helpful in ruling out the diagnosis in three patients.
Adult↗
Can general practitioners counsel?
It has been suggested that general practitioners are in a prime position to counsel patients presenting with psychosocial problems. While many doctors use counselling skills in their consultations few have received training in counselling and the difference between the use of counselling skills and the process of counselling is not always understood. This paper examines the differences between counselling and counselling skills and compares the role of doctors and counsellors. It is concluded that there is a need for trained counsellors to work alongside general practitioners and that this is of benefit to patients and all members of the primary care team.
Counseling↗
Drug testing in the military--technical and legal problems.
The Armed Forces drug-testing program has been in operation since 1971. Since that time, its goals, capabilities, and methods of operation have undergone extensive evolution and change. As these laboratories developed, they helped to establish many of the currently accepted operating standards for drug screening. For laboratories considering entry into the business of drug screening, an examination of the evolution and current operation of the military laboratories will be of benefit. It will help to define the currently accepted standards and NIDA guidelines and assist them to avoid the types of problems that were encountered by the military laboratories.
Gas Chromatography-Mass Spectrometry↗
Towards a rationalization of counselling in general practice.
While there is good evidence to show that counselling may be beneficial to those patients in general practice with non-organic problems, deployment of the available resources lacks standardization and rationalization. The Counselling in Medical Settings Working Party of the British Association for Counselling is pressing for standardized training and accreditation of counsellors so that general practitioners will feel more confident about taking on workers who will ultimately be incorporated into the NHS team.
Counseling↗
Selection of controls in testing for alcoholism.
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Alcoholism↗
Mobile consultation: an integrative approach to mental health service to children.
The authors describe the development of a consultation and education service in an inner-city catchment area. This service is unique in that its service pattern is integrated with a direct service component. It is implemented along a structural design incroporating a multidisciplinary mobile team responsive to variegated "consultation" requests from a dense population area with many first-line service providers of independent or insulated character. Satellite locations exist in specific neighborhoods to provide service. Consultation efforts are classified as services to individuals, groups, and the community at large.
Child↗
Regional Medical Program to serve nurses.
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Alaska↗
Detection and quantitation of urinary 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid, a metabolite of tetrahydrocannabinol, by capillary gas chromatography and electron impact mass fragmentography.
A procedure for detection and quantitation of 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid, a major metabolite of delta-9-tetrahydrocannabinol in urine, has been described. Since the metabolite is present in both conjugated and unconjugated forms, hydrolysis of urine was carried out to increase the sensitivity of detection. The acidic metabolite was isolated by strongly basic anion exchange resin, and subsequently derivatized to methyl 1-dehydroxy-1-methoxy-11-nor-delta-9-tetrahydrocannabinol-9-carbox ylate (1a) by methyliodide in the presence of tetramethylammonium hydroxide. The derivatized product was separated in a capillary column gas chromatograph, and finally detected by a mass spectrometer under electron impact mode. Confirmation of the product was carried out by monitoring three ions that represent the major portions of the molecule and comparing their relative abundances to that of a standard. Quantitation was based on 5'-2H3-11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid as internal standard. Excellent linearity was obtained over the range of 2 to 1000 ng/mL. The overall yield of extraction using the anion exchange resin was 50 to 60%. This extraction process is rapid and suitable for a large number of sample analyses. The methylated product (1a) is stable for at least 72 hr at room temperature.
Chromatography, Gas↗
GC/MS analysis of phencyclidine acid metabolite in human urine.
Available methods for determining PCP use are based on the presence of the parent drug in urine. PCP, however, is very potent and is extensively metabolized; it is therefore present in urine in only small quantities. This work was undertaken to determine whether an amino acid metabolite of PCP, 5-(N-(1'-phenylcyclohexyl)amino)pentanoic acid, can be used to determine PCP use. A solid phase adsorption technique was developed to extract the amino acid metabolite from urine. Recovery averaged 93%, and subsequent GC/MS analysis was free from interference. Analysis of 67 urine samples demonstrated that the amino acid metabolite exists in human urine in significant quantities.
Gas Chromatography-Mass Spectrometry↗
Gas chromatography/electron impact mass fragmentometric determination of urinary 6-acetylmorphine, a metabolite of heroin.
A procedure for detection and quantification of urinary 6-acetylmorphine (6-AM), a metabolite of heroin, is described. After initial solvent extraction from urine, the 6-AM was purified either by acid-base liquid-liquid extraction or by solid-phase extraction techniques. The 6-AM was then derivatized to its propionyl ester, which was characterized by gas chromatography/mass spectrometry in the electron impact mode. Confirmation of 6-AM was accomplished by comparing retention times and relative abundances of selected ions with that of a standard. Quantification was based on 6-[2H3]acetyl-N-[2H3]methylnormophine (6-[2H6]AM) as internal standard. Excellent linearity was obtained in the concentration range 1-100 ng/mL. The overall yield after solvent extraction and acid-base purification ranged from 79 to 82%; for solvent extraction and solid-phase purification, it was 92 to 95%. The limit of detection was 810 pg/mL. Within-run and between-run CVs for 6-AM at concentrations in the range 1-100 ng/mL were generally less than 5% and less than 10%, respectively.
Gas Chromatography-Mass Spectrometry↗
Evaluation of immunoassays for cannabinoids in urine.
A comparison was made of several cannabinoid urine assays. Two hundred randomly selected urine specimens were initially screened by two enzyme immunoassays (EMIT-st and EMIT-d.a.u.) and a radioimmunoassay (Abuscreen RIA). Selected specimens found positive by any of these methods were further analyzed by gas-liquid chromatography with flame ionization detection (GLC/FID), gas chromatography/mass spectrometry (GC/MS), and an experimental RIA from Research Triangle Institute (RTI RIA). The GLC/FID method gave confirmations in 69 to 92% of the samples, depending on the method used and the cut-off employed. GC/MS confirmed 98% of the EMIT and RIA positives using a low cut-off (20 ng/mL). All RIA positives at 100 ng/mL were confirmed by GC/MS. There was complete agreement between the RTI RIA and the EMIT assays, but not with the Abuscreen RIA at the 100 ng/mL cut-off. The study illustrates that care must be exercised in establishing assay cut-offs and the designation of false positive results.
Cannabinoids↗
Simultaneous identification and quantitation of codeine and morphine in urine by capillary gas chromatography and mass spectroscopy.
An analytical procedure for simultaneous determination of codeine and morphine in urine is described. The detection of codeine and morphine is based on liquid-liquid extraction and derivatization to the acetylated compounds. The acetylated codeine and morphine are separated by capillary gas chromatography and identified mass spectrometrically by selected ion monitoring (SIM). Quantitative determination was carried out by SIM using nalorphine as internal standard. Excellent linearity was obtained over a concentration range of 25 to 800 ng/mL. The overall recovery for codeine and morphine in the extraction was found to be 58% and 40%, respectively. The on-column sensitivity for both compounds was 2 ng at a peak-to-noise ratio of 5:1. The derivatives, acetylcodeine, diacetylmorphine, and diacetylnalorphine were stable at room temperature for 72 hr.
Codeine↗