Actualisation 2023 des lignes directrices de pratique clinique pour la prise en charge de l’ostéoporose et la prévention des fractures au Canada

Contexte:

Au Canada, plus de 2 millions de personnes vivent avec l’ostéoporose, une maladie qui accroît le risque de fracture, ce qui fait augmenter la morbidité et la mortalité, et entraîne une perte de qualité de vie et d’autonomie. La présente actualisation des lignes directrices vise à accompagner les professionnelles et professionnels de la santé au Canada dans la prestation de soins visant à optimiser la santé osseuse et à prévenir les fractures chez les femmes ménopausées et les hommes de 50 ans et plus.

Méthodes:

Le présent document fournit une actualisation des lignes directrices de pratique clinique de 2010 d’Ostéoporose Canada sur le diagnostic et la prise en charge de l’ostéoporose au pays. Nous avons utilisé l’approche GRADE (Grading of Recommendations Assessment, Development and Evaluation) et effectué l’assurance de la qualité conformément aux normes de qualité et de présentation des rapports de la grille AGREE II (Appraisal of Guidelines for Research & Evaluation). Les médecins de premier recours et les patientes et patients partenaires ont été représentés à tous les niveaux des comités et des groupes ayant participé à l’élaboration des lignes directrices, et ont participé à toutes les étapes du processus pour garantir la pertinence des informations pour les futurs utilisateurs et utilisatrices. Le processus de gestion des intérêts concurrents a été entamé avant l’élaboration des lignes directrices et s’est poursuivi sur toute sa durée, selon les principes du Réseau international en matière de lignes directrices. Dans la formulation des recommandations, nous avons tenu compte des avantages et des risques, des valeurs et préférences de la patientèle, des ressources, de l’équité, de l’acceptabilité et de la faisabilité; la force de chacune des recommandations a été déterminée en fonction du cadre GRADE.

Recommandations:

Les 25 recommandations et les 10 énoncés de bonne pratique sont répartis en sections : activité physique, alimentation, évaluation du risque de fracture, instauration du traitement, interventions pharmacologiques, durée et séquence du traitement, et monitorage. La prise en charge de l’ostéoporose devrait se fonder sur le risque de fracture, établi au moyen d’une évaluation clinique réalisée avec un outil d’évaluation du risque de fracture validé. L’activité physique, l’alimentation et la pharmacothérapie sont des éléments essentiels à la stratégie de prévention des fractures, qui devraient être personnalisés.

Interprétation:

Les présentes lignes directrices ont pour but d’outiller les professionnelles et professionnels de la santé et la patientèle afin qu’ensemble ils puissent parler de l’importance de la santé osseuse et du risque de fracture tout au long de la vie adulte avancée. La détection et la prise en charge efficace de la fragilité osseuse peuvent contribuer à réduire les fractures et à préserver la mobilité, l’autonomie et la qualité de vie.

Clinical practice guideline for management of osteoporosis and fracture prevention in Canada: 2023 update

BACKGROUND

In Canada, more than 2 million people live with osteoporosis, a disease that increases the risk for fractures, which result in excess mortality and morbidity, decreased quality of life and loss of autonomy. This guideline update is intended to assist Canadian health care professionals in the delivery of care to optimize skeletal health and prevent fractures in postmenopausal females and in males aged 50 years and older.

METHODS

This guideline is an update of the 2010 Osteoporosis Canada clinical practice guideline on the diagnosis and management of osteoporosis in Canada. We followed the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework and quality assurance as per Appraisal of Guidelines for Research and Evaluation (AGREE II) quality and reporting standards. Primary care physicians and patient partners were represented at all levels of the guideline committees and groups, and participated throughout the entire process to ensure relevance to target users. The process for managing competing interests was developed before and continued throughout the guideline development, informed by the Guideline International Network principles. We considered benefits and harms, patient values and preferences, resources, equity, acceptability and feasibility when developing recommendations; the strength of each recommendation was assigned according to the GRADE framework.

RECOMMENDATIONS

The 25 recommendations and 10 good practice statements are grouped under the sections of exercise, nutrition, fracture risk assessment and treatment initiation, pharmacologic interventions, duration and sequence of therapy, and monitoring. The management of osteoporosis should be guided by the patient's risk of fracture, based on clinical assessment and using a validated fracture risk assessment tool. Exercise, nutrition and pharmacotherapy are key elements of the management strategy for fracture prevention and should be individualized.

INTERPRETATION

The aim of this guideline is to empower health care professionals and patients to have meaningful discussions on the importance of skeletal health and fracture risk throughout older adulthood. Identification and appropriate management of skeletal fragility can reduce fractures, and preserve mobility, autonomy and quality of life.

Intra-individual comparison of 18F-sodium fluoride PET-CT and 99mTc bone scintigraphy with SPECT in patients with prostate cancer or breast cancer at high risk for skeletal metastases (MITNEC-A1): a multicentre, phase 3 trial

BACKGROUND

Detection of skeletal metastases in patients with prostate cancer or breast cancer remains a major clinical challenge. We aimed to compare the diagnostic performance of ^99mTc-methylene diphosphonate (^99mTc-MDP) single-photon emission CT (SPECT) and ¹⁸F-sodium fluoride (¹⁸F-NaF) PET-CT for the detection of osseous metastases in patients with high-risk prostate or breast cancer.

METHODS

MITNEC-A1 was a prospective, multicentre, single-cohort, phase 3 trial conducted in ten hospitals across Canada. Patients aged 18 years or older with breast or prostate cancer with a WHO performance status of 0-2 and with high risk or clinical suspicion for bone metastasis, but without previously documented bone involvement, were eligible. ¹⁸F-NaF PET-CT and ^99mTc-MDP SPECT were done within 14 days of each other for each participant. Two independent reviewers interpreted each modality without knowledge of other imaging findings. The primary endpoint was the overall accuracy of ^99mTc-MDP SPECT and ¹⁸F-NaF PET-CT scans for the detection of bone metastases in the per-protocol population. A combination of histopathological, clinical, and imaging follow-up for up to 24 months was used as the reference standard to assess the imaging results. Safety was assessed in all enrolled participants. This study is registered with ClinicalTrials.gov, NCT01930812, and is complete.

FINDINGS

Between July 11, 2014, and March 3, 2017, 290 patients were screened, 288 of whom were enrolled (64 participants with breast cancer and 224 with prostate cancer). 261 participants underwent both ¹⁸F-NaF PET-CT and ^99mTc-MDP SPECT and completed the required follow-up for statistical analysis. Median follow-up was 735 days (IQR 727-750). Based on the reference methods used, 109 (42%) of 261 patients had bone metastases. In the patient-based analysis, ¹⁸F-NaF PET-CT was more accurate than ^99mTc-MDP SPECT (84·3% [95% CI 79·9-88·7] vs 77·4% [72·3-82·5], difference 6·9% [95% CI 1·3-12·5]; p=0·016). No adverse events were reported for the 288 patients recruited.

INTERPRETATION

¹⁸F-NaF has the potential to displace ^99mTc-MDP as the bone imaging radiopharmaceutical of choice in patients with high-risk prostate or breast cancer.

FUNDING

Canadian Institutes of Health Research.

Use of radioiodine-131 scan to measure influence of surgical discipline, practice, and volume on residual thyroid tissue after total thyroidectomy for differentiated thyroid carcinoma

BACKGROUND

Our study's purpose is to determine the influence of surgical discipline, surgeon site, and volume on remnant thyroid tissue visualized on radioactive iodine-131 (I-131) scans after total thyroidectomy and I-131 ablation in patients with well-differentiated thyroid carcinomas.

METHODS

We retrospectively reviewed all cases of patients who received I-131 therapeutic ablation and postablation radioactive I-131 scans at our center after thyroidectomy to calculate the fraction of administered dose multiplied by 1000 (UDR1000).

RESULTS

The remnant thyroid tissue (ie, the UDR1000), between academic and community surgeons was 0.471 (±0.705) and 1.190 (±2.487), respectively (P = .001). The UDR1000 between otolaryngology-head and neck surgery and general surgery was 0.654 (±1.575) and 1.043 (±1.625), respectively (P = .159). The UDR1000 partitioned by patient frequencies of <10, 10 to 19, and ≥20 patients yielded 1.255 (±2.554), 0.926 (±2.084), and 0.467 (±0.721), respectively (P = .003).

CONCLUSION

Our study found statistically significant differences in residual thyroid tissue visualized on radioactive I-131 scans based on surgeon parameters.

Development and evaluation of a website for surveillance of healthcare-associated urinary tract infections in Australia

Phase II of the Surveillance to Reduce Urinary Tract Infections project piloted a website for point prevalence surveys of healthcare-associated (HAUTI) and catheter-associated urinary tract infection in Australian hospitals and aged care homes. This report describes development and evaluation of the website for online data collection. Evaluation findings from 38 data collectors indicated that most respondents found website registration and web form use easy (N = 22; 58% and N = 16; 43%, respectively). The need for improved computer literacy skills and automated data systems were highlighted. This study demonstrated a novel approach for Australian HAUTI data collection; however, refinements are needed before national roll-out.

Early detection of cerebral glucose uptake changes in the 5XFAD mouse

Brain glucose hypometabolism has been observed in Alzheimer’s disease (AD) patients, and is detected with ¹⁸F radiolabelled glucose, using positron emission tomography. A pathological hallmark of AD is deposition of brain β-amyloid plaques that may influence cerebral glucose metabolism. The five times familial AD (5XFAD) mouse is a model of brain amyloidosis exhibiting AD-like phenotypes. This study examines brain β-amyloid plaque deposition and ¹⁸FDG uptake, to search for an early biomarker distinguishing 5XFAD from wild-type mice. Thus, brain ¹⁸FDG uptake and plaque deposition was studied in these mice at age 2, 5 and 13 months. The 5XFAD mice demonstrated significantly reduced brain ¹⁸FDG uptake at 13 months relative to wild-type controls but not in younger mice, despite substantial β-amyloid plaque deposition. However, by comparing the ratio of uptake values for glucose in different regions in the same brain, 5XFAD mice could be distinguished from controls at age 2 months. This method of measuring altered glucose metabolism may represent an early biomarker for the progression of amyloid deposition in the brain. We conclude that brain ¹⁸FDG uptake can be a sensitive biomarker for early detection of abnormal metabolism in the 5XFAD mouse when alternative relative uptake values are utilized.

Initial experience of a rapid-insertion bone-anchored hearing system: series of 20 consecutive implants

Objective: The loading of bone-anchored hearing system sound processors usually occurs two to three months after surgical implant. This study examined a new bone-anchored hearing system coupling mechanism that permits loading at two weeks post-implantation without compromising osseointegration. Methods: Twenty implants were implanted into 15 patients. The interval between operation and time of processor loading was recorded, along with the cause of any delay and any late complications. Results: Two patients were fitted with implants at seven and nine weeks. The delay was a result of administrative errors; the patients reported no skin problems. Of the remaining 17 implants, 8 processors were fitted at 2 weeks, 1 at 3 weeks, 4 at 4 weeks, 3 at 7 weeks and 1 at 8 weeks. For those nine implants fitted later than two weeks, the delay was because of incomplete skin healing. Conclusion: The Oticon Medical Xpress system allowed processor loading at two weeks post-operatively, providing skin healing was adequate. Early loading occurred in approximately half of the patients. All patients were fitted within the two to three months traditionally allowed. Prolonged skin healing time was the main reason for the delayed fitting of sound processors.

Is lower socioeconomic status associated with more advanced thyroid cancer stage at presentation? A study in two Canadian centers

BACKGROUND

Some studies have shown a higher incidence of thyroid cancer in patients with insurance coverage and higher socioeconomic status (SES), and a higher thyroid cancer stage in patients with lower SES, suggesting SES-related health disparity in thyroid cancer. However, it is not known if the same is evident under a universal healthcare system such as that in Canada.

METHODS

We used data from the Canadian Thyroid Cancer Consortium, a large thyroid cancer registry that collects data from two major thyroid cancer referral centers (London, Ontario, and Halifax, Nova Scotia). We included patients who presented with thyroid cancer between 1998 and 2011. We determined age at presentation, sex, and thyroid cancer status using the American Joint Committee on Cancer (AJCC) staging criteria. Individuals' postal codes were used to retrieve data from the Canadian census for the years 1996, 2001, and 2006 to approximate household income. Ordered logistic regression was used to determine odds ratios of presenting with more advanced stage thyroid cancer as they relate to income, age, and sex.

RESULTS

We included 1701 patients: 1334 cases from London and 367 from Halifax. Thyroid cancer was diagnosed more frequently in the higher SES groups (p<0.001). Compared to patients in the top income quintile, patients in the lowest and second-lowest income quintiles had significantly higher odds of having more advanced stage thyroid cancer at presentation (OR 1.58, p=0.002; 1.37, p=0.024 respectively).

CONCLUSIONS

Our study suggests that, similar to countries that lack a universal healthcare system, health disparity in thyroid cancer also exists in Canada. It appears that while thyroid cancers were diagnosed more frequently in Canadian patients of higher SES, Canadian patients in the lower SES groups had more advanced stage thyroid cancer at presentation.

PET/CT aids the staging of and radiotherapy planning for early-stage extranodal natural killer/T-cell lymphoma, nasal type: a case series

Extranodal natural killer/T-cell lymphoma (ENKTL), nasal type, is a rare form of non-Hodgkin lymphoma. Treatment of ENKTL primarily relies on radiation; thus, proper delineation of target volumes is critical. Currently, the ideal modalities for delineation of gross tumor volume for ENKTL are unknown. We describe three consecutive cases of localized ENKTL that presented to the Nova Scotia Cancer Centre in Halifax, Nova Scotia. All patients had a planning CT and MRI as well as a planning FDG-PET/CT in the radiotherapy treatment position, wearing immobilization masks. All patients received radiation alone. In two patients, PET/CT changed not only the stage, but also the target volume requiring treatment. The third patient was unable to tolerate an MRI, but was able to undergo PET/CT, which improved the accuracy of the target volume. PET/CT aided the staging of and radiotherapy planning for our patients and appears to be a promising tool in the treatment of ENKTL.

Infrequently performed studies in nuclear medicine: part 2

Nuclear medicine is a diverse medical field, encompassing a wide range of studies. Many studies are performed on a daily basis, whereas some nuclear medicine studies are performed on a more infrequent basis. The following article is the second article in a 2-part series on infrequently performed studies in nuclear medicine. The procedures reviewed include CSF shunt imaging, brain death scintigraphy, testicular scanning, quantitative lung perfusion studies, lymphoscintigraphy, and salivary gland scintigraphy. This article may be of use to technologists faced with the task of performing one of these uncommon studies. After reviewing the article, the reader should be able to list the indications for each study, list the recommended doses, describe the proper method of dose administration for each study, discuss patient preparation for each procedure, and describe issues that may arise when performing these studies.

Laparoscopic accessory splenectomy: the value of perioperative localization studies

BACKGROUND

Laparoscopic splenectomy is an effective treatment for many patients with immune thrombocytopenic purpura (ITP) who fail or relapse after treatment with steroids. Patients with an incomplete response to splenectomy and those who experience recurrence of symptoms should be evaluated for the presence of an accessory spleen. The clinical effectiveness of laparoscopic excision of an accessory spleen after a previous splenectomy for ITP has varied in different studies. Laparoscopic intraoperative identification of an accessory spleen can be difficult. The authors report their experience with laparoscopic accessory splenectomy (LAS) and the use of perioperative localization methods for this procedure.

METHODS

This study reviewed seven consecutive patients who underwent LAS, after initial splenectomy failed to cure ITP, at a tertiary care center between April 9, 2003 and March 31, 2008. Demographics, diagnostic and localization studies, technical success, and the effect on thrombocytopenia were examined. The location of the accessory spleen also was recorded. A novel method for localizing accessory spleen was used. It consisted of preoperative computed tomography (CT)-guided injection of methylene blue at the accessory spleen's site, preoperative intravenous injection of 99m-technetium-labeled, heat-damaged red blood cells, or both. Intraoperatively, the dye was used for visual identification, and the gamma probe was used to aid in locating and confirming the presence of the accessory spleen in the excised specimen.

RESULTS

Seven patients with recurrent ITP after initial failed splenectomy underwent LAS during the study period. Five of these patients had the initial splenectomy performed laparoscopically. All seven patients had successful laparoscopic removal of the accessory spleen based on a final pathologic examination. One patient required the second laparoscopic exploration with perioperative localization after a failed attempt without it. These perioperative localization methods were used in subsequent operations on other patients. These methods were found to be helpful in the intraoperative identification of the accessory spleens. The accessory spleens missed at initial splenectomy were found in unusual locations. Five of the seven patients had sustained improvement in platelet counts after LAS. One patient had a postoperative ileus that resolved with nonoperative management. No other complications or mortality was observed.

CONCLUSION

The LAS procedure after previous splenectomy is feasible and safe. Perioperative localization methods aid in the intraoperative identification of an accessory spleen. Accessory spleens missed at initial splenectomy are generally found in unusual locations. Treatment of recurrent or unresolved ITP with LAS can be effective for some patients.

Infrequently performed studies in nuclear medicine: Part 1

Nuclear medicine is a diverse field with a large number of different studies spanning virtually all organ systems and medical specialties. Many nuclear medicine procedures are performed routinely; others may be performed only rarely, sometimes less than once per year. The infrequent nature of many studies makes it challenging to retain relevant knowledge and skills. This 2-part article provides a review of several infrequently performed studies. The topics discussed in Part 1 include dacroscintigraphy, LeVeen shunts, scintimammography, right-to-left shunts, left-to-right shunts, and heat-damaged red blood cells. After reading this article, the reader should be able to list and describe the indications for each study, list the doses and describe their proper method of administration, and describe problems that may arise during the imaging procedure and how they should be handled.

Artifacts and pitfalls in myocardial perfusion imaging

Myocardial perfusion imaging (MPI) is an important imaging modality in the management of patients with cardiovascular disease. MPI plays a key role in diagnosing cardiovascular disease, establishing prognosis, assessing the effectiveness of therapy, and evaluating viability. However, MPI is a complex process, subject to a variety of artifacts and pitfalls, which may limit its clinical utility. These factors may be related to the patient (including unique aspects of the patient's heart), the nuclear medicine equipment, or the actions of the technologist. After reviewing this article, the reader should be familiar with the causes and the effects of these potential artifacts and pitfalls. The reader should develop an understanding of steps to limit these factors, actions to correct them if they do arise and, when necessary, how to incorporate their influence into the interpretation of the study.

Erdheim-Chester disease of the breast: a case report and review of the literature

Erdheim-Chester disease (ECD) is a rare xanthomatous non-Langerhans cell histiocytosis which involves the marrow space of the long bones. Extraosseous sites most commonly affected include the eyes, lungs, pituitary glands, and kidneys. We report the case of a 49-year-old woman who presented with palpable breast nodules, followed by progressive soft tissue and subcutaneous disease, and involvement of the long bones, dysarthria, and dysphagia. The histopathologic features and skeletal radiography findings are consistent with ECD. This case represents an unusual presentation, which led to delayed diagnosis, as ECD of the breast has been rarely reported. ECD should be considered in the differential diagnosis of histiocytoid breast lesions, including fat necrosis and histiocytoid invasive mammary carcinoma.

Intravascular T-cell lymphoma with bowel involvement: case report and literature review

Intravascular lymphoma (IVL) is a rare form of non-Hodgkin lymphoma characterized by massive proliferation of large, neoplastic cells in small- and medium-sized blood vessels. Most cases of IVL are of B-cell immunophenotype; fewer than 15 cases of T-cell IVL have been reported. A 23-year-old male presented with acute abdominal pain, fever, and tender lower abdomen. Pathology at laparotomy revealed infiltration of colonic vessels with large lymphoid cells compatible with IVL. We reviewed all cases of IVL diagnosed at the Queen Elizabeth II Health Sciences Centre in Halifax, Nova Scotia, from August 1992 to August 2002. A literature review was also performed. Five additional cases of IVL were identified at this institution during a 10-year period. Three patients presented with neurological symptoms, and two with abdominal pain. In 4 of 5 cases, patients died of lymphoma within 3 months of presentation; one patient experienced a 10-month remission. While visceral involvement with IVL is common at autopsy, IVL presenting as an acute abdomen in an immunocompetent patient has not previously been described. Among the 15 cases of T-cell IVL reported in the literature, only two occurred in people under age 30. Given the rarity of T-cell IVL, it is remarkable that three cases of T-cell IVL have been diagnosed at our institution during a 10-year period.

Intracranial presentation of systemic Hodgkin's disease

Intracranial involvement by Hodgkin's disease is rare. We report a patient with Hodgkin's disease who had intracranial disease at presentation. We also review the literature pertaining to intracranial Hodgkin's disease. Using the key words "Hodgkin's disease" and "central nervous system (CNS) disease", we searched the Pubmed and Cancerlit databases. References were systematically reviewed and data regarding the following variables was extracted: age, gender, signs and symptoms at presentation, histology of Hodgkin's disease, cerebrospinal fluid analysis, stage and treatment. Only 36 cases of intracranial Hodgkin's disease were identified in the literature. Intracranial Hodgkin's disease at presentation is even more uncommon with only 8 reported cases. Most cases of intracranial involvement by Hodgkin's disease occur at the time of relapse. The most common presenting feature of intracranial Hodgkin's disease is a cranial nerve palsy with brain parenchyma being the most common intracranial site of involvement. Mixed cellularity histology is the most frequent subtype of Hodgkin's disease among these patients and the median survival following intracranial presentation is 46 months. Treatment has varied extensively but includes whole brain radiation with or without combination chemotherapy. Our literature review suggests that the prognosis is not dismal with appropriate treatment.

Single photon emission computed tomography perfusion imaging for assessment of myocardial viability and management of heart failure

In the setting of coronary artery disease, some areas of dysfunctional myocardium may realize significant improvement in function as a consequence of revascularization. These areas represent viable myocardium, encompassing a spectrum of pathophysiology ranging from chronic stunning, in which resting blood flow is preserved, to hibernating myocardium, in which resting blood flow is decreased. The accurate preoperative evaluation of viable myocardium helps identify those patients with left ventricular dysfunction who will most benefit from coronary revascularization. Of the various modalities available for viability assessment, the nuclear medicine techniques (201)Thallium and (18)Fluorodeoxyglucose positron emission tomography have emerged as the most sensitive. It has been consistently shown that in patients with a significant amount of viable myocardium, there is a substantial survival benefit in revascularization versus medical therapy. The likelihood of affecting a significant improvement decreases with time to revascularization, however, particularly in the setting of an enlarged left ventricle secondary to ventricular remodeling.

Fear and frustration--the Liverpool cholera riots of 1832

Public mistrust in the medical profession is not new. We describe a series of street riots that took place in the city of Liverpool in north-west England in 1832 during a cholera epidemic. The disturbances were directed primarily against the local medical fraternity. The episode is of interest, since the same city recently experienced a similar crisis of confidence between doctors and public. On this occasion the cause was not cholera, but rather the reports from Alder Hey Children's Hospital that organ parts from deceased infants undergoing necropsy had been kept for several years without parental consent.

Ontogeny of beta 2 glycoprotein I and annexin V in villous placenta of normal and antiphospholipid syndrome pregnancies

beta2-glycoprotein I (beta2GPI) and annexin V (AV) have been implicated in the pathophysiology of the antiphospholipid syndrome (APS). We investigated their placental expression in normal villous tissues throughout gestation; first trimester n = 10, early second trimester; n = 4, preterm; n = 5) and term; n = 7 and in APS (2 first trimester, 1 preterm and 8 term deliveries). beta2GPI and AV were both expressed by the placenta from as early as seven weeks gestation and were colocalised to the syncytiotrophoblast. beta2GPI staining was also observed in stromal cells, being present in phagocytic Hofbauer cells and surrounding newly formed fetal vessels in a perivascular pattern, from seven to seventeen weeks gestation. An abnormal morphological distribution of AV was noted in one first trimester APS placenta, and for beta2GPI in a further first trimester placenta. When placental proteins were extracted from villous tissue, the concentration of AV/mg protein in term APS placentas (median, interquartile range) (aPS; 8.16, 7.879.72 microg/mg) was significantly higher (p <0.005) than normal term levels (normal; 2.47, 2.28-2.54 microg/mg). beta2GPI increased with advancing gestation (first trimester; 0.93, 0.64-1.26 microg/mg, term; 3.67, 2.58-4.48 microg/mg) in normal pregnancy. Term APS placentas had a reduced beta2GPI content (2.31, 1.87-2.49 microg/mg), p <0.05. The placental role of these proteins remains to be identified.

Characterization of P2 receptors for purine and pyrimidine nucleotides in human placental cotyledons

1. The aim of this study was to characterize P2 receptors in the arterial vascular bed of human perfused placental cotyledons. Vasoconstrictor responses to bolus injections of purine and pyrimidine nucleotides were tested at basal tone, and vasodilator responses in preparations with tone raised by perfusion with prostaglandin F2alpha (PGF2alpha; 10-50 nM). 2. At basal tone, bolus injections of the P2X-selective agonist alpha,beta-methylene ATP (alpha,beta-meATP; 0.5-500 nmol) elicited dose-dependent vasoconstriction. ATP (0.005-5 micromol) also elicited dose-dependent vasoconstriction, but was less potent than alpha,beta-meATP. Vasoconstriction was also elicited by other nucleotides, but only at the highest dose tested (5 micromol): UTP > CTP = ITP (n = 6). GTP and TTP did not cause vasoconstriction. 3. Constrictor responses to bolus injections of alpha,beta-meATP were resistant to desensitization and were not significantly affected when carried out in the presence of 1 microM alpha,beta-meATP added to the perfusate. However, responses to bolus injections of alpha,beta-meATP were partially blocked by perfusion with 10 microM alpha,beta-meATP. In contrast, responses to ATP and UTP were unaffected by 10 microM alpha,beta-meATP. The P2X receptor antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS; 10 and 100 microM) had no significant effect on vasoconstriction mediated by alpha,beta-meATP and ATP. 4. Removal of the endothelium had no significant effect on constrictor responses to alpha,beta-meATP, ATP and UTP. Inhibition of nitric oxide (NO) synthesis with N(G)-nitro-L-arginine methyl ester (L-NAME; 100 microM) had no significant effect on vasoconstriction to ATP and alpha,beta-meATP. 5. In preparations with tone raised with PGF2alpha (10-50 nM) vasodilatation was elicited by nucleotides with the following order of potency: 2MeSATP = ADP >> ATP > UTP > CTP = GTP = ITP = TTP. pD2 values were: 2MeSATP, 10.03+/-0.26 (n=7); ADP, 9.97+/-0.40 (n=5); ATP, 8.89+/-0.18 (n=7); UTP, 7.79+/-0.35 (n=7). Maximal responses to 2MeSATP and ADP were similar and were approximately 40% greater than maximal responses to ATP and UTP. 6. Vasodilator responses to nucleotides were abolished by L-NAME (100 microM) and by removal of the endothelium. 7. In conclusion, contractile responses mediated by alpha,beta-meATP and ATP in human placental smooth muscle are resistant to desensitization and insensitive to PPADS and, thus, show a dissimilar pharmacological profile to the classic smooth muscle P2X1 receptor. There may be two subtypes of smooth muscle P2 receptor based on differential antagonism of alpha,beta-meATP and ATP with alpha,beta-meATP. A smooth muscle P2 receptor mediates vasoconstriction to UTP, and may indicate a further subtype. Endothelium-dependent, NO-dependent, vasodilatation to 2MeSATP and ADP may be mediated by P2Y1 receptors, while endothelial P2Y2 receptors are likely to mediate NO-dependent relaxation to ATP and UTP.

A review of solvent abusers and their management by a child psychiatric out-patient service

1 This study reviews 45 solvent abusers referred, over a 3-year period, to the Departments of Child Psychiatry attached to a large postgraduate teaching hospital.

2 Abusers are considered in 3 defined groups: chronic, periodic, experimental.

3 Boys predominate mainly in the group of chronic abusers, where a strong association is seen with delinquent behaviour and disrupted family backgrounds.

4 Many chronic users report transient symptoms of a toxic psychosis. A marked affective component may be evident, often depressive in character.

5 Systemic physical symptoms are common, especially amongst chronic users. Weight loss, nausea and vomiting, acute bronchospasm, cardiac arrhythmias have all been reported.

6 Other illicit drug use is widespread through the whole sample, but of little significance. Most children report alcohol and cigarette consumption, use of which can be very heavy.

7 Treatment was offered to most children, and comprised mainly family and individual work. A favourable outcome was correlated with high motivation, at least 6 months' duration of out-patient attendance, or with residential care and therapy. Approximately half the children who were chronic or periodic users had improved at follow-up.

8 Recommendations for more systematic recording of solvent abuse have been made as a result of these findings. All cases in the future will be separately registered, and their progress followed prospectively.