A 4pi(LS)beta-gamma coincidence system using a TDCR apparatus in the beta-channel

This article is an overview of the capabilities of a 4 pi(LS)beta-gamma coincidence counting system based on a liquid scintillation detector in the beta-channel. Equipped with a three-photomultiplier apparatus designed for the triple to double coincidence ratio (TDCR) method, the 4 pi(LS)beta-gamma coincidence system developed at LNHB combines the two techniques. The 4 pi(LS)beta-gamma counting setup records the different types of scintillation events between photomultipliers (double and triple coincidences) and the associated gamma-spectra according to a bi-dimensional configuration. When measuring the activity of a (54)Mn solution, the extrapolation method is carried out by defocusing the photomultipliers; this procedure allows the measurement of gamma-ray sensitivity of the scintillation cocktail in the 835 keV energy region. In addition, in the framework of a (65)Zn standardization, 4 pi(LS)beta-gamma measurements are compared with standard 4 pi(PC)beta-gamma anticoincidence counting using a proportional counter in the beta-channel.

Freeze-drying applied to radioactive source preparation

In the framework of R&D studies for the improvement of radioactive source efficiencies prepared on thin films for 4pibeta-gamma coincidence counting, a comparative study on two drying methods has been undertaken in our laboratory (BNM-Laboratoire National Henri Becquerel, France). The standard method of evaporation at atmospheric pressure and a method based on freeze-drying using commercial equipment are compared. The preliminary results of this study obtained with 65Zn sources are presented and a significant improvement of the detection efficiencies to the electron emission for freeze-dried sources is shown. In the course of validation of this method, other radionuclides were studied and, up to now, the results confirm the better crystallization homogeneity achieved for freeze-dried sources.

Half-life determination of 88Y and 89Sr

Half-life measurements have been carried out at LNHB for 88Y using a 4pi gamma-ionisation chamber and for 89Sr using a proportional counter. The determined half-life values and associated standard uncertainties are 106.63 +/- 0.05 d for 88Y and 50.65 +/- 0.05 d for 89Sr, being consistent with relevant values reported in literature. Based on the present results and relevant literature values revised recommended half-life values and associated standard uncertainties are proposed, viz. 106.626 +/- 0.021 d for 88Y and 50.57 +/- 0.03 d for 89Sr.

High-energy resolution X-ray, gamma and electron spectroscopy with cryogenic detectors

Cryogenic detectors offer remarkably better energy resolutions than those achievable with conventional semiconductor or scintillation detectors. With the additional asset of a detection efficiency close to unity for low-energy X-ray photons and electrons, these detectors have the potential to perform X-ray, gamma and electron spectroscopy of a hitherto unknown quality, in particular at low energies. Two types of cryogenic detectors are described and the results of prototype detectors are presented.

The role of cocaine in fatal crashes: first results of the Québec drug study

As part of a major undertaking to establish the contribution of drugs in road crashes in Quebec, the present study focuses on the role of cocaine. Coroner, forensic laboratory and police accident records from April 1999 to December 2000 were matched for 265 fatally injured drivers of passenger vehicles. Cocaine was found in 7.9% of urine samples and 6.0% of blood samples. In order to set up a control group, two roadside surveys were conducted in August 1999 and 2000. The survey sample was distributed proportionately to the number of fatal accidents per time of day and day of the week. During both daytime and nighttime, a total of 11,952 drivers participated in the two surveys among which 11,574 provided a breath sample (96.8%), 8,177 a saliva sample (68.4%) and 5,931 a urine sample (49.6%). Cocaine was detected in 1.1% of urine samples and 1.0% of saliva samples of the driving population. In both fatally injured drivers and driving population, cocaine was found mostly (> 90%) in four main types of combination: cocaine alone, cocaine + cannabis, cocaine + alcohol, cocaine + cannabis + alcohol. The data collected allowed two different analyses: a case-control (urine/urine) and a responsibility analysis (case-case approach) that compares cocaine cases to drug-free cases. Despite some data limitations, all analyses for the four main types of combination clearly suggest that cocaine use plays a role in fatal crashes.

A new set of electronic modules (NIM standard) for a coincidence system using the pulse mixing method

The three electronic modules presented here, connected to two MTR2 modules of extended dead-time discriminators, allow setting-up a complete coincidence system according to the principle of the pulse-mixing method. Results produced by such a system including these modules were compared with those of an older system working in a completely different mode (IMPECC).

A new absolute method for the standardization of radionuclides emitting low-energy radiation

Microcalorimeters (or bolometers) operated at temperatures below 100 mK allow individual counting of photons and electrons with a very low energy detection threshold. The physics is based on the pulse temperature increase of the target (or absorber) of the detector due to the complete absorption of both electrons and photons. Since this target can be constructed with a perfect 4-pi geometry, a bolometer offers potentially a new method for absolute activity measurements of radionuclides emitting low-energy radiation. In this paper we present our first results of a feasibility study of activity standardization of a 55Fe solution with a prototype 4-pi bolometer.

Is the standard compliance check protocol a valid measure of the accessibility of tobacco to underage smokers?

OBJECTIVE

To determine if the standard compliance check protocol is a valid measure of the experience of underage smokers when purchasing tobacco in unfamiliar communities.

SETTING

160 tobacco outlets in eight Massachusetts communities where underage tobacco sales laws are vigorously enforced.

PROCEDURE

Completed purchase rates were compared between underage smokers who behaved normally and inexperienced non-smoking youths who were not allowed to lie or present proof of age (ID).

RESULTS

The "smoker protocol" increased the likelihood of a sale nearly sixfold over that for the non-smokers (odds ratio (OR) 5.7, 95% confidence interval (CI) 1.5 to 22). When the youths presented an ID with an underage birth date, the odds of a completed sale increased dramatically (OR 27, 95% CI 3.4 to 212). Clerks judged to be under 21 years of age were seven times more likely to make an illegal sale (OR 7.6, 95% CI 2.4 to 24.0).

CONCLUSIONS

Commonly used compliance check protocols are too artificial to reflect accurately the experience of underage smokers. The validity of compliance checks might be improved by having youths present ID, and by employing either tobacco users, or non-tobacco users who are sufficiently experienced to mimic the self confidence exhibited by tobacco users in this situation. Consideration should be given to prohibiting the sale of tobacco by individuals under 21 years of age.

Ambulatory use of inhaled beta(2)-agonists for the treatment of asthma in Quebec : a population-based utilization review

STUDY OBJECTIVES

To assess whether the utilization of inhaled short-acting beta(2)-agonists (ISAB) and inhaled long-acting beta(2)-agonists (ILAB) for the treatment of asthma was appropriate according to the 1996 Canadian Asthma Consensus Conference recommendations.

DESIGN

Population-based retrospective drug utilization review using pharmacists' billing data of the Prescription Drug Insurance Plan administered by the Quebec health insurance board. However, the database used did not contain complete patient clinical information to accurately assess severity of asthma.

SETTING

Province of Quebec, Canada.

PATIENTS

Persons who received at least one outpatient prescription of ISAB (age range, 5 to 45 years) or ILAB (age range, 12 to 45 years) for the treatment of asthma between August 1997 and April 1998.

MEASUREMENTS

Percentages of patients whose use was appropriate according to three criteria regarding the average daily dose of ISAB (criterion 1), the renewal interval of ILAB (criterion 2), and the concomitant daily use of corticosteroids for the expected length of utilization of ILAB (criterion 3).

RESULTS

Overall proportions of appropriate use according to criterion 1 were as follows: 75% (without inhaled corticosteroids [ICS]) and 84% and 43% (with one or more than one prescription of ICS, respectively). Appropriateness was slightly higher for female patients, younger patients (5 to 18 years old), and those treated by pediatricians. However, appropriateness was only 9% among patients who received at least two prescriptions of ISAB during the study period. The proportion of appropriate use was 19% according to criterion 2 and 15% according to criterion 3; there were few differences by gender or by age, but the appropriateness according to criterion 2 was somewhat higher for patients of respirologists.

CONCLUSION

Compared to the 1996 Canadian asthma consensus conference recommendations, ISAB are overused, ICS are underused, and ILAB are often used improperly. Close collaboration between health professionals and patients is essential to improve the pharmacotherapy of asthma.

A multinational investigation of the impact of subcutaneous sumatriptan. I: Design, methods and clinical findings

This report describes the design, methods and clinical results of a prospective sequential multinational (5 countries) study conducted to evaluate the effects of subcutaneous sumatriptan on health-related quality of life, workplace productivity, clinical parameters and patient satisfaction. Adult patients with moderate to severe migraine initially received customary therapy for migraine episodes for 12 weeks, followed by 24 weeks' treatment with self-administered subcutaneous sumatriptan 6 mg. Demographic, baseline, health-related quality of life and patient satisfaction rating data were collected during visits to the clinic. Data relating to migraine symptoms, migraine therapy, work productivity and non-work activity time were collected on diary cards filled out by the patients. 749 patients were recruited to the study and 637 received at least 1 dose of sumatriptan. Overall, 75.5% of migraines were successfully treated within 2 hours with sumatriptan compared with 31.9% with customary therapy; 36% of patients reported complete relief at 2 hours with sumatriptan treatment compared with 1% of patients receiving customary therapy. 69% of patients successfully treated 70% of their migraines with sumatriptan within 2 hours, compared with 12% of patients with customary therapy. No serious adverse events were reported; 50% of patients reported an adverse event during the 12-week customary therapy phase and 89% of patients during the 24-week sumatriptan phase. These clinical results, which are consistent with those reported in randomised blinded studies of subcutaneous sumatriptan, suggest that relief of migraine symptoms occurs more often, and in less time, in patients receiving subcutaneous sumatriptan rather than customary therapy as their primary medication.

A multinational investigation of the impact of subcutaneous sumatriptan. IV: Patient satisfaction

This report describes the patient satisfaction results from a prospective, sequential, multinational study. The study was conducted to concurrently evaluate the effects of sumatriptan, compared with customary therapy, on clinical parameters, health-related quality of life, productivity and patient satisfaction in adult patients with moderate to severe migraine. Patients treated migraine attacks for 12 weeks with their customary therapy, followed by 24 weeks' treatment with subcutaneous sumatriptan 6 mg. A questionnaire was conducted at the end of each study phase, or retrospectively at the end of the study, to assess patient satisfaction with customary therapy and sumatriptan. Sumatriptan was considered by most patients (67 to 85%) to be dependable and fast-acting, and to have a long duration of effect, allowing a quick return to normal activities. By comparison, 15 to 32% of patients considered that their customary therapy possessed the same attributes. However, customary therapy was considered to be easy/very easy to use by 82% of patients compared with 62% for subcutaneous sumatriptan. 89% of patients indicated that they would use sumatriptan again in the future. This study demonstrates that treatment of migraine attacks with subcutaneous sumatriptan for 24 weeks is associated with greater patient satisfaction as regards specific drug attributes than customary therapy.

A multinational investigation of the impact of subcutaneous sumatriptan. III: Workplace productivity and non-workplace activity

This report presents the workplace productivity and non-workplace activity results of a multinational study of the effects of subcutaneous sumatriptan 6 mg in the acute treatment of migraine compared with patient's customary therapy. Patients diagnosed with migraine treated their symptoms for 24 weeks with subcutaneous sumatriptan after a 12-week period of treating symptoms with their customary (non-sumatriptan) therapy. Patients used diary cards to record information concerning the effects of migraine on workplace productivity and non-workplace activity time. The average workplace productivity time lost was 23.4 hours per patient during 12 weeks of customary therapy, compared with 7.2 and 5.8 hours per patient during the first and second 12-week periods of sumatriptan therapy, respectively. An average of 9.3 hours of non-workplace activity time was lost per patient during the customary therapy phase, compared with 3.2 and 2.8 hours during the first and second 12-week periods of sumatriptan therapy, respectively. Treatment of migraine with subcutaneous sumatriptan compared with customary therapy was associated with an average gain per patient of approximately 16 hours of workplace productivity time and 6 hours of non-workplace activity time, over a 3-month period.

A multinational investigation of the impact of subcutaneous sumatriptan. II: Health-related quality of life

The aim of this prospective sequential multinational (5 countries) study was to concurrently evaluate the effects of subcutaneous sumatriptan on clinical parameters, health-related quality-of-life (HRQOL) measures, workplace productivity and patient satisfaction. This report presents the HRQOL results. 582 patients (aged 18 to 65 years) with moderate to severe migraine received their customary antimigraine therapy for 12 weeks and then subcutaneous sumatriptan for 24 weeks. The Short Form-36 Health Survey and the Migraine-Specific Quality of Life Questionnaire were completed at a screening visit (base-line), at the end of the 12-week customary therapy phase, and at 12 and 24 weeks of the sumatriptan phase. Scores for most of the Short Form-36 dimensions improved significantly (p < 0.05) after 12 and 24 weeks of sumatriptan therapy compared with 12 weeks of customary therapy, in each country. Similarly, scores on all Migraine-Specific Quality of Life Questionnaire dimensions were significantly (p < 0.05; paired t-test) improved after 12 weeks (in all countries) and 24 weeks (in 4 of 5 countries) of sumatriptan therapy compared with 12 weeks of customary therapy. This study demonstrates that, in 5 countries, treatment of migraine attacks with subcutaneous sumatriptan compared with customary therapy was associated with improvements in HRQOL, as measured by both general health status and disease-specific instruments.

Altered mRNA expression due to insertion or substitution of thymine at position +3 of two splice-donor sites in the androgen receptor gene

We have discovered two types of 5' intronic gene mutation that impair androgen receptor (AR) mRNA expression severely, and cause complete androgen insensitivity. Labium majus skin fibroblasts (LMSF) hemizygous for each mutation had negligible specific androgen binding, and did not react to an antibody against an N-terminal peptide of the AR. Both mutations were detected by direct sequencing of exons PCR-amplified with flanking primers. One mutation is an adenine to thymine transversion at position +3 of the intron 6 splice-donor site. Using LMSF mRNA, RT-PCR of a portion of the AR androgen-binding domain yielded a small amount of a 302-bp mutant fragment instead of a 433-bp wild-type product. Sequencing established that exon 5 was followed, out of frame, by exon 7: exon 6 was skipped. The other mutation is a thymine insertion at the +3 position of the intron 1 donor-splice site. RT-PCR and sequencing revealed a small amount of normal-size mRNA with normal exon 1-exon 2 splicing. Quantitative RT-PCR on mutant LMSF showed AR mRNA levels were well below 10% of normal; hence, most of the aberrant AR mRNA resulting from each mutation is probably unstable. The misbehavior caused by these two mutations indicates that in the AR the splice-donor site +3 adenine is critical; indeed, 57% of eukaryotic introns have adenine in the +3 position, while only 2% have thymine.

Kraft pulp bleaching using dimethyldioxirane: stability of the oxidants

Dimethyldioxirane (DMD) is a cyclic peroxide made by oxidizing acetone with peroxymonosulfate (PMS) in water buffered at pH 7.5 using sodium bicarbonate. It has been shown that DMD generation can be achieved in situ within a pulp suspension allowing very selective TCF bleaching of kraft pulp. This process involves simultaneous generation of DMD, reaction of PMS and DMD with residual lignin, and spontaneous decomposition of both oxidants. The first part of this work is a kinetics study of the decomposition of PMS and DMD as a function of pH under conditions similar to those for in situ bleaching. The effect of chelation as well as the effect of transition metal ions on decomposition rate was also investigated. DMD is very sensitive to pH and its half-life is very short under alkaline conditions. The presence of any transition metal ion that can be involved in a one-electron transfer is detrimental to DMD stability. However, fast reaction of DMD with pulp almost counteracts the effect of metal ions. Key words: bleaching, peroxymonosulphate, dimethyldioxirane, metal ions, kinetics, decomposition, kraft pulp.

Postoperative heterotopic ossification in children: a comparison of children with spina bifida and with cerebral palsy

The authors reviewed 250 consecutive myotomies and tenotomies performed on the hips of 186 children. Two groups were studied: 162 children with cerebral palsy and 24 children with spina bifida. In total 19 children were found to have heterotopic ossification postoperatively. The incidence of heterotopic ossification was 21% in the spina bifida group and 8.6% in the cerebral palsy group. The most severe cases were in children with thoracic myelomeningocele. Only one child with lumbar myelomeningocele had ossification, and it was mild. This difference was statistically significant. Two children with thoracic spina bifida had severe ossification and abduction contractures requiring resection of the bony mass. Recurrence was successfully prevented by a course of radiotherapy.

5-azacytidine and 5-azadeoxycytidine inhibit human immunodeficiency virus type 1 replication in vitro

Chemotherapeutic agents which affect the integration, stability, or inducibility of the human immunodeficiency virus (HIV) provirus would have considerable value in treating acquired immunodeficiency syndrome. Two nucleoside analogs of cytosine, 5-azacytidine and 5-azadeoxycytidine, which seem to have such value because of their capabilities to affect both the stability and the methylation patterns of the nucleic acids into which they are incorporated, were tested for their ability to inhibit the replication of HIV type 1 (HIV-1) in human CEM T cells in vitro. 5-Azadeoxycytidine (1 microM) completely inhibited HIV replication in CEM cells, by the criteria of reduced viral antigen expression and decreased supernatant reverse transcriptase activity, with little toxicity for the treated cells. 5-azacytidine (1 microM) also inhibited HIV replication, but less effectively. When added 2 or more h after CEM cells were infected with HIV-1, both 5-azacytosine derivatives were less effective than they were when added at the time of infection. Even 2 h of exposure to 5-azadeoxycytidine was sufficient for inhibition of HIV replication. Although long exposure to either analog at concentrations of 1 microM would result in pronounced cellular cytotoxicity, the the fact that short exposures to the same dose of drug inhibit HIV replication but are not toxic for the cells implies that cellular toxicity itself is not an important mechanism of the antiviral action of the analogs.

Hypersecretion of gonadotropins by a pituitary adenoma: pituitary dynamic studies and treatment with bromocriptine in one patient

Pituitary adenomas secreting gonadotropins are often diagnosed as nonsecreting tumors on the basis of clinical findings. We now describe a middle-aged woman who developed visual disturbances and was found to have a large infiltrating pituitary adenoma secreting large quantities of follicle-stimulating hormone (FSH) with moderate elevation of luteinizing hormone (LH). The patient twice underwent transsphenoidal microsurgery to partially remove the adenoma. Thereafter, a trial with bromocriptine was initiated. Normal levels of FSH and LH were observed after 6 weeks of treatment as well as improvement of visual field examination. This case illustrates the fact that some gonadotropin-secreting adenomas can be extremely sensitive to dopamine agonist adenomas can be extremely sensitive to dopamine agonist therapy.

The degradation of Indulin ATR by Streptomyces: chemical characterization of the water soluble acid precipitable products

Two strains of Streptomyces, S. badius and S. virdosporus, when incubated with kraft lignin (Indulin ATR) produce water soluble acid precipitable compounds. We show by a combination of elemental analysis, amino acid analysis, and FTIR that these are complexes of lignin fragments strongly associated with proteins. The latter, which can be separated by solvent extraction, are added by the microorganisms themselves. The lignin fraction, which represents approximately 60% of the complex weight, consists of lower molecular weight, lower methoxyl content Indulin fragments. KeyWords: lignin, Indulin, lignin–protein complexes, Fourier transform infrared spectrophotometry, high performance size exclusion chromatography, Streptomyces.

Mechanism of action of 5-AZA-dC: induced DNA hypomethylation does not lead to aberrant gene expression in human leukemic CEM cells

To understand the mechanism of action of 5-AZA-2'-deoxycytidine, a potent antineoplastic agent, we studied its effect in CEM cells on DNA methylation while monitoring coinciding changes in DNA, RNA and protein synthesis. At concentrations near the inhibitory concentration, the drug induced a profound reduction of DNA methylation. Effects on DNA and RNA synthesis were also noted at 24 and 48 h of treatment. However, at all concentrations assayed, no change in polypeptide composition as monitored by 2-D gel electrophoresis, were observed. That the cytotoxic effect of 5-AZA-deoxycytidine is due to changes in gene expression induced by DNA methylation reduction is not supported.