Comparison of six cannabinoid metabolite assays

Numerous methods for the detection of urinary metabolites of marijuana constituents are available. Documentation of the sensitivity and specificity of these tests is needed before the determination of a pair of screening-confirmation tests can be made. This study used 88 clinical specimens to evaluate five commercially available marijuana metabolite methods and one new gas chromatography/mass spectrometry (GC/MS) method. The EMIT-d.a.u. test was found to have 2 to 3% unconfirmed positives when compared to the other methods evaluated. The new thin layer procedure, TOXI-LAB, was not as sensitive as the EMIT-d.a.u. procedure for some specimens, but proved to be a good confirmation for the EMIT-d.a.u. with elimination of all "unconfirmed positives." The Abuscreen (Roche) and the EMIT-st assays were positive for samples that contained larger amounts of 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid (11-nor-delta 9-THC-9-COOH). The Immunalysis-radioimmunoassay (RIA) was positive for all samples found positive by the GC/MS method, but the concentrations found by the two assays did not correlate. The GC/MS method was developed to use the same extraction as the thin layer procedure and provides confirmation for all procedures except 2 to 3% of the positive EMIT-d.a.u. results.     

Raising the ambient potassium ion concentration enhances carbachol stimulated phosphoinositide hydrolysis in rat brain hippocampal and cerebral cortical miniprisms

Summary The influence of the ambient potassium ion concentration ([K⁺]_ upon agonist stimulated hydrolysis of phosphoinositides (PI) has been studied in isolated miniprisms of rat hippocampus and cerebral cortex. When the external [K⁺] was raised from 6 to 18 mmol/l, there was little or no increase in the hydrolysis of PI in the absence of agonist, however, carbachol (100 mol/l) stimulated hydrolysis was greatly enhanced in both brain regions studied. Thus, carbachol stimulated the hydrolysis of PI to 146% and 386% of control levels at potassium concentrations of 5.8 and 18.2 mmol/l, respectively, in the rat hippocampus. A similar enhancement of muscarine (100 mol/l) stimulation was observed in cortical miniprisms with 18 mmol/l [K⁺]. A further enhancement was seen at higher ambient [K⁺], although basal hydrolysis of PI was then also increased. The carbachol-stimulated hydrolysis of PI found at both 6 and raised [K⁺] was prevented by atropine (1 and 10 mol/l) and tetraethylammonium (20 mmol/l), but not by 10 mmol/l Mg²⁺. Pirenzepine (50 nmol/l) also reduced this response. The ions Cs⁺ and Rb⁺ (but not Li⁺ or Tris⁺) produced a similar enhancement of the carbachol stimulation to that found with K⁺. At a buffer [K⁺] of 6 mmol/l, noradrenaline (100 mol/l) produced a 2-fold increase in the hydrolysis of PI whereas 5-hydroxytryptamine (100 mol/l) and histamine (500 mol/l) had little or no effect. However, histamine and 5-hydroxytryptamine did stimulate the hydrolysis of PI when [K⁺] was increased. Miniprism ATP content was not changed by a rise in [K⁺] to 18 mmol/l. The significance of these results is discussed in terms of the postsynaptic cellular events following cholinergic stimulation.     

Stereoselective inhibition of monoamine oxidase and semicarbazide-sensitive amine oxidase by 4-dimethylamino-2,α-dimethylphenethylamine (FLA 336)

Summary The in vitro inhibition by amiflamine [FLA 336(+)] and related compounds of the activity of rat monoamine oxidase (MAO)-A and-B, rat semicarbazide sensitive amine oxidase (SSAO) and human platelet poor plasma benzylamine oxidase was studied. Amiflamine was an MAO-A selective inhibitor, but also inhibits SSAO with both a reversible (competitive, K _i=200 mol/l) and a small time-dependent component which was irreversible in nature. The optical isomer FLA 336(–) was ten times less potent towards MAO-A. However, this compound was much more potent an inhibitor of SSAO (competitive, K _i=4.6 mol/l). The amiflamine metabolites FLA 788(+) and FLA 668(+) inhibited SSAO, but only at concentrations considerably higher than required for MAO-A inhibition. Ex vivo experiments indicated that there was no significant irreversible inhibition of rat heart and lung SSAO after both single and repeated administration of amiflamine at doses up to 20 times higher than required for inhibition of MAO-A within central serotoninergic neurones.     

Changes in extracellular adenosine levels and population spike amplitude during graded hypoxia in the rat hippocampal slice

Summary Concentrations of adenosine and inosine in the incubation media of baths containing rat hippocampal slices were measured during graded hypoxia. Slices were exposed to atmospheres containing 95%, 71%, 48%, 24%, or 0% oxygen, with 5% CO₂ and a balance of N₂. Absorbance HPLC measurements were made with samples drawn from static tissue baths each containing four slices supported on a net at the interface between the medium and the atmosphere. Concentrations of adenosine and inosine were proportionate to the fractional oxygen content. They were significantly higher in atmospheres of 24% and 0% O₂. Introducing a 95% N₂/5% O₂ atmosphere in place of 95% O₂/5% CO₂ resulted in a roughly 4-fold increase in the adenosine concentration in the bath. The adenosine transport blocker dipyridamole (200 M), and the convulsant drug picrotoxinin (300 M), had little effect on basal levels of adenosine measured at 95% O₂ but significantly augmented the responses seen at 48%, 24% and 0% O₂. Picrotoxinin, while increasing the adenosine concentration did not change the ratio of adenosine to inosine. In contrast, dipyridamole significantly increased the ratio of adenosine to inosine. Evoked population spikes were recorded from the CA1 layer. The population spike amplitude was depressed as the fractional oxygen content was reduced. It is concluded that adenosine regulation in the slice preparation is similar to that seen in the intact animal. In particular, the amounts of adenosine released into the incubation medium are related to oxygen availability.     

Redo hepatic resection for metastatic colorectal carcinoma

Redo hepatic resection for recurrent colorectal metastasis was performed in eight patients. There was no operative mortality; major morbidity occurred in 25% and minor morbidity in 13% of patients. Four patients are alive and disease-free at 9, 23, 39, and 49 months, respectively, after their repeat hepatic resection. Four patients have died of recurrent disease, with a median time to recurrence of 6 months and median survival of 15 months. Patterns of failure include hepatic failure alone in two patients and pulmonary and hepatic failure in two. Repeat liver resection can be performed safely and may be beneficial in some patients with recurrent metastases confined to the liver after previous hepatic metastasectomy.

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Resumen El tratamiento quirúrgico de las metástasis hepáticas recurrentes luego de una resección inicial no ha sido considerado como opción terapeútica. Sin embargo, varios informes recientes han documentado el hecho de que la resección repetida es técnicamente factible y que puede resultar en prolongados intervalos libres de enfermedad en 38% a 50% de los pacientes. Con anterioridad al présente reporte, solo 62 pacientes sometidos a resección hepática repetida por cancer colorrectal metastásico han sido descritos en la literatura. Se requieren estudios adicionales, y nuestro grupo présenta su experiencia para complementar esta base de datos.Se describe la resección redo-hepática por metástasis colorrectales recurrentes en ocho pacientes. No hubo mortalidad operatoria, se registró morbilidad mayor en 25% y menor en 13%. Cuatro pacientes se encuentran vivos y libres de enfermedad a los 9, 23, 39 y 49 meses después de la nueva resección hepática. Cuatro pacientes han muerto por enfermedad récurrente con un tiempo medio de recurrencia de 6 meses, y un tiempo medio de sobrevida de 15 meses. Los lugares de falla incluyen sólo dos en el hígado y dos en el pulmón. La resección repetida del hígado puede ser realizada con seguridad y puede ser beneficiosa en algunos pacientes con metástasis récurrentes confinadas al hígado después de una metastasectomía previa.

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Résumé La résection itérative de métastases hépatiques d'un cancer colorectal a été pratiquée chez 8 patients. Il n'y a eu aucune mortalité opératoire. La morbidité majeure a été de 25% (2 patients), alors qu'elle a été mineure chez un patient (13%). Quatre patients sont en vie et apparement sans maladie à 9, 23, 39, et 49 mois après leur deuxième résection. Quatre patients sont morts de récidive avec une médiane d'intervalle libre avant la récidive de 6 mois, et une survie médiane de 15 mois. La récidive a été dans deux cas au niveau du foie seul et dans deux autres cas, simultanément au niveau du poumon et du foie. La résection itérative de métastases hépatiques est faisable avec sûreté et peut apporter un plus chez certains patients déjà opérés de leur métastase.

     

A growth opportunity. Catholic hospitals can improve their mission and margin by developing rehabilitation services

Developing rehabilitation services should be an attractive diversification strategy for Catholic hospitals during the 1990s. Although the number of inpatient rehabilitation providers more than doubled during the 1980s, many markets remain underserved. Rehabilitation units can enable facilities to generate revenues and, at the same time, better serve the community. A number of other factors make creating rehabilitation programs a sound venture: Hospitals can choose from among a variety of product lines when deciding which services to include; reimbursement mechanisms are at present favorable to rehabilitation; businesses are making increasing use of these services; the segment of the population that most often requires rehabilitation services is growing; and many acute care hospitals have a ready-made source of rehabilitation referrals in their occupied beds. For Catholic healthcare facilities now offer teritary or subspecialty programs and have developed sophisticated ancillary services, they are well placed to add rehabilitation programs.     

Rapid assessment of dietary intake of fat, fiber, and saturated fat: validity of an instrument suitable for community intervention research and nutritional surveillance

Abstract Traditional methods to assess changes in dietary intake, for example food frequency questionnaires or 24-hour dietary recalls, are often not practical: they are lengthy, expensive, and unsuitable for telephone administration. This article describes the development and evaluation of an approach to the rapid assessment of the dietary intake of nutrients of most interest in health promotion research; total fat, saturated fat, dietary fiber, and percent of calories from fat. In this validation study on 97 women, short dietary questionnaires were compared to two criterion measures of usual dietary intake, a food frequency questionnaire and the mean of two four-day diet records. Correlations between self-administered short questionnaires and four-day diet records were 0.52, 0.53, 0.61, and 0.40 for total fat, percent of calories from fat, saturated fat, and dietary fiber, respectively. These correlations are similar to those observed between food frequency questionnaires and four-day diet records, which suggests that this approach to developing and administering short dietary questionnaires may be useful in situations where more expensive and time-consuming methods of dietary assessment are not practical.     

Model for the integrated network? Rehabilitation makes a good candidate

Rehabilitation is a good model for an integrated delivery network (IDN). Because it is an integral part of the treatment plans of a diverse group of medical specialties, rehab often plays a pivotal role in patients' recovery. Since its focus is on functional outcomes, rehab is compatible with a capitated payment system. In addition, rehab entered the managed care arena before other "product lines," so rehab providers have experience with diverse reimbursement conditions. And although rehab encompasses all levels of care, it is not too large to function as a model for a full-scale IDN. There are four key stages in the development of a rehab IDN: A strong leader with a clear vision organizes a working committee composed of the key leaders of each entity involved in rehab: hospitals, nursing homes, home health, and others. The committee begins to design the proposed network. Though the committee may study other IDNs, its focus is on its own organization's needs and objectives. A master plan addressing systems gaps and opportunities throughout the IDN is drawn up. Integral to the plan is a schedule according to which each of the network's components will be integrated. The master plan is implemented. The working committee determines the IDN's final structure and names the members of the management team.     

Arsenic: health effects, mechanisms of actions, and research issues.

A meeting on the health effects of arsenic (As), its modes of action, and areas in need of future research was held in Hunt Valley, Maryland, on 22-24 September 1997. Exposure to As in drinking water has been associated with the development of skin and internal cancers and noncarcinogenic effects such as diabetes, peripheral neuropathy, and cardiovascular diseases. There is little data on specific mechanism(s) of action for As, but a great deal of information on possible modes of action. Although arsenite [As(III)] can inhibit more than 200 enzymes, events underlying the induction of the noncarcinogenic effects of As are not understood. With respect to carcinogenicity, As can affect DNA repair, methylation of DNA, and increase radical formation and activation of the protooncogene c-myc, but none of these potential pathways have widespread acceptance as the principal etiologic event. In addition, there are no accepted models for the study of As-induced carcinogenesis. At the final meeting session we considered research needs. Among the most important areas cited were a) As metabolism and its interaction with cellular constituents; b) possible bioaccumulation of As; c) interactions with other metals; d) effects of As on genetic material; e) development of animal models and cell systems to study effects of As; and f) a better characterization of human exposures as related to health risks. Some of the barriers to the advancement of As research included an apparent lack of interest in the United States on As research; lack of relevant animal models; difficulty with adoption of uniform methodologies; lack of accepted biomarkers; and the need for a central storage repository for stored specimens.     

Intimate combination of low- and high-resolution image data: I. Real-space PET and (1)H(2)O MRI, PETAMRI.

Two different types of (co-registered) images of the same slice of tissue will generally have different spatial resolutions. The judicious pixel-by-pixel combination of their data can be accomplished to yield a single image exhibiting properties of both. Here, axial (18)FDG PET and (1)H(2)O MR images of the human brain are used as the low- and high-resolution members of the pair. A color scale is necessary in order to provide for separate intensity parameters from the two image types. However, not all color scales can accommodate this separability. The HSV color model allows one to choose a color scale in which the intensity of the low-resolution image type is coded as hue, while that of the high-resolution type is coded as value, a reasonably independent parameter. Furthermore, the high-resolution image must have high contrast and be quantitative in the same sense as the low-resolution image almost always is. Here, relaxographic MR images (naturally segmented quantitative (1)H(2)O spin-density components) are used. Their essentially complete contrast serves to effect an apparent editing function when encoded as the value of the color scale. Thus, the combination of (18)FDG PET images with gray-matter (GM) relaxographic (1)H(2)O images produces visually "GM-edited" (18)FDG PETAMR (positron emission tomography and magnetic resonance) images. These exhibit the high sensitivity to tracer amounts characteristic of PET along with the high spatial resolution of (1)H(2)O MRI. At the same time, however, they retain the complete quantitative measures of each of their basis images. Magn Reson Med 42:345-360, 1999. Published 1999 Wiley-Liss, Inc.