Cannabis use among adolescents and young adults during the COVID-19 pandemic: A systematic review

Background

A systematic review of the literature was performed to summarize cannabis use among adolescents and young adults during the COVID-19 pandemic. Special focus was given to the prevalence of cannabis use during COVID-19, as well as factors that may explain changes in cannabis consumption patterns.

Methods

The protocol of this systematic review was registered. Articles from seven publication databases were searched in January 2022. The inclusion criteria for studies were as follows: 1) published in English; 2) study instruments needed to include items on COVID-19; 3) conducted after January 1st, 2020; 4) published in a peer-reviewed journal, dissertation, or thesis; 5) study population ≤25 years of age; 6) study designs were limited to observational analytical studies; 7) measured cannabis use. This review excluded other reviews, editorials, and conference abstracts that were not available as full text manuscripts. Independent review, risk of bias assessment, and data abstraction were performed by two authors.

Results

Fifteen articles from the United States (n=11) and Canada (n=4) were included in this review. The findings of this review showed that the prevalence of cannabis use during the pandemic among adolescents and young adults were mixed. Some mental health symptoms, including depression and anxiety, were identified as the most commonly reported reasons for increased cannabis use during the pandemic.

Conclusions

This review highlights the inconsistencies in the prevalence of cannabis use among adolescents and young adults during the pandemic. Therapeutic interventions for mental health and continued public health surveillance should be conducted to understand the long-term effects of cannabis use among adolescents and young adults.

Educational Intervention to Increase COVID-19 Vaccine Uptake in Rural Patients with Chronic Diseases: Lessons Learned from An Innovative Academic-Community Partnership

BACKGROUND

The pandemic has disproportionately impacted rural communities with a higher burden of chronic disease and COVID-19 infection. West Virginia is a rural state with a high rate of diabetes, hypertension, and COPD, which are known risk factors for severe COVID-19 and long COVID. Yet, there is a significant hesitancy regarding COVID-19 vaccination uptake in the state. The purpose of this study was to use an educational intervention to increase vaccine knowledge and vaccine acceptance in rural patients with chronic disease(s) in West Virginia. This project used an academic-community partnership comprised of researchers, practitioners, community organizations, community-engaged partners, and patient stakeholders to increase COVID-19 health literacy and increase vaccine acceptance among rural West Virginians with chronic conditions.

MATERIALS AND METHODS

A quasi-experimental study design was used to deliver an educational intervention by trained Health Navigators using short videos to increase COVID-19 health literacy and address participants' vaccine concerns. Eligibility included adults (18 years and older) who have at least one chronic condition. A statewide community advisory board (CAB) guided the development of the educational training curriculum and implementation strategies. An adapted version of the Exploration, Preparation, Implementation, Sustainment (EPIS) framework guided the development of the intervention. Health Navigators (n = 45) delivered the educational intervention in their local communities between November 2022 and October 2023 (project implementation is still ongoing). Intervention fidelity checks, an adaptable script, and a flow chart allowed tailoring of brief videos to address participants' specific COVID-19 questions and vaccine concerns. A validated online survey, monitored by an online Research Electronic Data Capture (REDCap) database, assessed participants' knowledge, perceived susceptibility, and vaccine intention.

RESULTS

Health Navigators delivered the intervention to 1368 West Virginians in 52 counties (59.2% women; 61.8% without a college degree). Participants reported living with an average of 2.1 ± 1.4 chronic conditions. The mean age was 43.5 ± 18.8 years. The majority of participants (81.2%) had received the primary vaccination series, and 63.1% had at least one booster. However, 18% were unvaccinated or did not complete the primary COVID-19 vaccine series. Discussions to improve vaccine literacy focused on how the vaccine was so quickly developed and protects against variants, addressing concerns related to the safety, short- and long-term side effects, and importance of vaccine uptake for immunocompromised individuals. Participants with higher concerns were more likely to be unvaccinated and to have not completed their primary series or boosters (p < 0.001). However, the educational intervention improved the willingness of individuals who were either unvaccinated or did not complete their primary vaccine series to get vaccinated (11.4%).

DISCUSSION

Our findings highlight the importance of vaccine literacy in increasing vaccination rates among rural patients with chronic diseases. Using the EPIS framework allowed us to reflect upon the challenges, ensure resilience during changing local contexts, and plan and implement a promising, cost-effective intervention in rural areas.

CONCLUSIONS

This study provides insights into the need for tailored educational interventions based on disease status, which has implications for public health and patient care in rural and underserved communities. Academic-community partnerships can be useful for successful knowledge transfer for vaccine acceptance to reduce rural health disparities.

Impact of Season and Other Factors on Initiation, Discontinuation, and Switching of Systemic Drug Therapy in Patients with Psoriasis: A Retrospective Study

This study investigated whether systemic drug prescribing for psoriasis varies by season and other exacerbating factors. Eligible patients with psoriasis were assessed for each season for initiation, discontinuation, and switching of systemic drugs. A total of 360,787 patients were at risk of initiating any systemic drugs in 2016‒2019; 39,572 patients and 35,388 patients were at risk of drug discontinuation or switching to a biologic and a nonbiologic systemic drug, respectively. The initiation of biologic therapy in 2016‒2019 peaked in spring (1.28%), followed by summer (1.11%), fall (1.08%), and winter (1.01%). Nonbiologic systemic drugs followed a similar pattern. Those aged 30‒39 years, male, those with psoriatic arthritis, those who live in the South region, those who live in areas with lower altitudes, and those who live in areas with lower humidity had higher initiation with the same seasonality pattern. Discontinuation of biologic drugs peaked in summer, and switching of biologics was highest in spring. Season is associated with initiation, discontinuation, and switching, although seasonality pattern is less clear for nonbiologic systemic drugs. Approximately 14,280 more patients with psoriasis in the United States are estimated to initiate a biologic in spring than in other seasons, and over 840 more biologic users switched in spring than in winter. The findings may provide evidence for healthcare resource planning in psoriasis management.

Real-world comparative effectiveness of mRNA-1273 and BNT162b2 vaccines among immunocompromised adults identified in administrative claims data in the United States

INTRODUCTION

Head-to-head studies comparing COVID-19 mRNA vaccine effectiveness in immunocompromised individuals, who are vulnerable to severe disease are lacking, as large sample sizes are required to make meaningful inferences.

METHODS

This observational comparative effectiveness study was conducted in closed administrative claims data from the US HealthVerity database (December 11, 2020-January 10, 2022, before omicron). A 2-dose mRNA-1273 versus BNT162b2 regimen was assessed for preventing medically-attended breakthrough COVID-19 diagnosis and hospitalizations among immunocompromised adults. Inverse probability of treatment weighting was applied to balance baseline characteristics between vaccine groups. Incidence rates from patient-level data and hazard ratios (HRs) using weighted Cox proportional hazards models were calculated.

RESULTS

Overall, 57,898 and 66,981 individuals received a 2-dose regimen of mRNA-1273 or BNT161b2, respectively. Among the weighted population, mean age was 51 years, 53 % were female, and baseline immunodeficiencies included prior blood transplant (8%-9%), prior organ transplant (7%), active cancer (12%-13%), primary immunodeficiency (5-6%), HIV (20%-21%), and immunosuppressive therapy use (60%-61%). Rates per 1,000 person-years (PYs; 95% confidence intervals [CI]s) of breakthrough medically-attended COVID-19 were 25.82 (23.83-27.97) with mRNA-1273 and 30.98 (28.93, 33.18) with BNT162b2 (HR, 0.83; 95% CI, 0.75-0.93). When requiring evidence of an antigen or polymerase chain reaction test before COVID-19 diagnosis, the HR for medically-attended COVID-19 was 0.78 (0.67-0.92). Breakthrough COVID-19 hospitalization rates per 1,000 PYs (95% CI) were 3.66 (2.96-4.51) for mRNA-1273 and 4.68 (3.91-5.59) for BNT162b2 (HR, 0.78; 0.59-1.03). Utilizing open and closed claims for outcome capture only, or both cohort entry/outcome capture, produced HRs (95% CIs) for COVID-19 hospitalization of 0.72 (0.57-0.92) and 0.66 (0.58-0.76), respectively.

CONCLUSIONS

Among immunocompromised adults, a 2-dose mRNA-1273 regimen was more effective in preventing medically-attended COVID-19 in any setting (inpatient and outpatient) than 2-dose BNT162b2. Results were similar for COVID-19 hospitalization, although statistical power was limited when using closed claims only.

STUDY REGISTRATION

NCT05366322.

Relationship Among Diabetes Distress, Health Literacy, Diabetes Education, Patient-Provider Communication and Diabetes Self-Care

OBJECTIVES

Mechanisms underlying relationships among patients' health literacy, diabetes distress, diabetes education, and provider counseling for self-care of chronic conditions are unclear. This study tested these relationships using SEM with adult patients with comorbid diabetes and hypertension in rural WV.

METHODS

Ninety-one participants of a 12-week self-management program reported on diabetes self-care (diet, exercise, blood glucose (BG) monitoring) and related provider counseling.

RESULTS

Based on patient report, providers' recommendations included following a low-fat diet, eating fruits/ vegetables, limiting sweets, a daily low-level of exercise and/or exercise ≥20 minutes three times/week, and BG monitoring. Provider recommendations were shown to be associated with patients' self-care behaviors (r=0.22, p<0.05). Multiple factors directly influenced provider recommendations: diabetes distress, health literacy, and family history of diabetes. A positive association was also noted between prior diabetes education and provider recommendations and diabetes self-care (r=0.44, p<0.001). A negative association was noted between diabetes distress and self-care, but a positive effect on provider recommendations was found. The model demonstrated good fit [CFI=0.94, and Root Mean Square Error of Approximation (RMSEA) =0.05].

CONCLUSIONS

To enhance diabetes self-care, providers should consistently provide education on self-care behaviors as well as partner with them to address diabetes distress.

Addressing Uncertainty in Informal Familial Caregivers of Stroke Survivors: A Systematic Meta-Ethnography

Background: Informal familial caregivers of stroke survivors experience uncertainty that begins at the time of the stroke event and continues into home-based care. The uncertainty faced by caregivers contributes to poor mental and physical health outcomes. Objective: This review details the factors associated with, impacts of, and coping skills used to manage uncertainty across the caregiving trajectory. By defining uncertainty reduction and tolerance recommendations, this review also builds upon the Stroke Caregiver Readiness Model to improve preparedness following the stroke event. Methods: A meta-ethnographic review was systematically conducted on thirteen qualitative studies with 218 participants from four countries. The Critical Appraisal Skills Programme (CASP) was used to assess study quality. Results: Following the stroke event, caregivers reported a lack of knowing (e.g., about the cause of the stroke event and survivor prognoses) as contributing to post-stroke uncertainty. As a result of this uncertainty, caregivers expressed concerns about their abilities to navigate caregiving responsibilities and how to plan for the future. Longer-term concerns (e.g., managing finances) and feelings of hopelessness occurred after discharge. Still, caregivers identified strategies to manage uncertainty. Caregiver coping skills included present-focused thinking, gratitude, faith, humor, and social support. Conclusions: The uncertainty faced by informal familial caregivers of stroke survivors is pervasive and changes across time. Uncertainty reduction and tolerance interventions can be used to build upon caregiver strengths and promote preparedness across the caregiving trajectory.

Screening, Diagnosis and Management of Sarcopenia and Frailty in Hospitalized Older Adults: Recommendations from the Australian and New Zealand Society for Sarcopenia and Frailty Research (ANZSSFR) Expert Working Group

Sarcopenia and frailty are highly prevalent conditions in older hospitalized patients, which are associated with a myriad of adverse clinical outcomes. This paper, prepared by a multidisciplinary expert working group from the Australian and New Zealand Society for Sarcopenia and Frailty Research (ANZSSFR), provides an up-to-date overview of current evidence and recommendations based on a narrative review of the literature for the screening, diagnosis, and management of sarcopenia and frailty in older patients within the hospital setting. It also includes suggestions on potential pathways to implement change to encourage widespread adoption of these evidence-informed recommendations within hospital settings. The expert working group concluded there was insufficient evidence to support any specific screening tool for sarcopenia and recommends an assessment of probable sarcopenia/sarcopenia using established criteria for all older (≥65 years) hospitalized patients or in younger patients with conditions (e.g., comorbidities) that may increase their risk of sarcopenia. Diagnosis of probable sarcopenia should be based on an assessment of low muscle strength (grip strength or five times sit-to-stand) with sarcopenia diagnosis including low muscle mass quantified from dual energy X-ray absorptiometry, bioelectrical impedance analysis or in the absence of diagnostic devices, calf circumference as a proxy measure. Severe sarcopenia is represented by the addition of impaired physical performance (slow gait speed). All patients with probable sarcopenia or sarcopenia should be investigated for causes (e.g., chronic/acute disease or malnutrition), and treated accordingly. For frailty, it is recommended that all hospitalized patients aged 70 years and older be screened using a validated tool [Clinical Frailty Scale (CFS), Hospital Frailty Risk Score, the FRAIL scale or the Frailty Index]. Patients screened as positive for frailty should undergo further clinical assessment using the Frailty Phenotype, Frailty Index or information collected from a Comprehensive Geriatric Assessment (CGA). All patients identified as frail should receive follow up by a health practitioner(s) for an individualized care plan. To treat older hospitalized patients with probable sarcopenia, sarcopenia, or frailty, it is recommended that a structured and supervised multi-component exercise program incorporating elements of resistance (muscle strengthening), challenging balance, and functional mobility training be prescribed as early as possible combined with nutritional support to optimize energy and protein intake and correct any deficiencies. There is insufficient evidence to recommend pharmacological agents for the treatment of sarcopenia or frailty. Finally, to facilitate integration of these recommendations into hospital settings organization-wide approaches are needed, with the Spread and Sustain framework recommended to facilitate organizational culture change, with the help of 'champions' to drive these changes. A multidisciplinary team approach incorporating awareness and education initiatives for healthcare professionals is recommended to ensure that screening, diagnosis and management approaches for sarcopenia and frailty are embedded and sustained within hospital settings. Finally, patients and caregivers' education should be integrated into the care pathway to facilitate adherence to prescribed management approaches for sarcopenia and frailty.

Effects of the Selective Serotonin Reuptake Inhibitor Fluoxetine on Developing Neural Circuits in a Model of the Human Fetal Cortex

The developing prenatal brain is particularly susceptible to environmental disturbances. During prenatal brain development, synapses form between neurons, resulting in neural circuits that support complex cognitive functions. In utero exposure to environmental factors such as pharmaceuticals that alter the process of synapse formation increases the risk of neurodevelopmental abnormalities. However, there is a lack of research into how specific environmental factors directly impact the developing neural circuitry of the human brain. For example, selective serotonin reuptake inhibitors are commonly used throughout pregnancy to treat depression, yet their impact on the developing fetal brain remains unclear. Recently, human brain models have provided unprecedented access to the critical window of prenatal brain development. In the present study, we used human neurons and cortical spheroids to determine whether the selective serotonin reuptake inhibitor fluoxetine alters neurite and synapse formation and the development of spontaneous activity within neural circuits. We demonstrate that cortical spheroids express serotonin transporter, thus recapitulating the early developmental expression of serotonin transporter associated with cortical pyramidal neurons. Cortical spheroids also appropriately express serotonin receptors, such as synaptic 5-HT2A and glial 5-HT5A. To determine whether fluoxetine can affect developing neural circuits independent of serotonergic innervation from the dorsal and medial raphe nuclei, we treated cortical neurons and spheroids with fluoxetine. Fluoxetine alters neurite formation in a dose-dependent fashion. Intriguingly, in cortical spheroids, neither acute nor chronic fluoxetine significantly altered excitatory synapse formation. However, only acute, but not chronic fluoxetine exposure altered inhibitory synaptogenesis. Finally, fluoxetine reversibly suppresses neuronal activity in a dose-dependent manner. These results demonstrate that fluoxetine can acutely alter synaptic function in developing neural circuits, but the effects were not long-lasting. This work provides a foundation for future studies to combine serotonergic innervation with cortical spheroids and assess the contributions of fluoxetine-induced alterations in serotonin levels to brain development.

Non-Pharmacological Interventions in Osteosarcopenia: A Systematic Review

BACKGROUND

Osteosarcopenia is a geriatric syndrome defined by the concomitant presence of osteopenia/osteoporosis (loss of bone mineral density (BMD)) and sarcopenia (loss of muscle mass and/or function), which increases the risk of falls, fractures, and premature mortality.

OBJECTIVE

To examine the efficacy of non-pharmacological (exercise and/or nutritional) interventions on musculoskeletal measures and outcomes in osteosarcopenic adults by reviewing findings from randomized controlled trials (RCTs).

METHODS

This review was registered at PROSPERO (registration number: CRD42020179292) and conducted in accordance with the PRISMA guidelines. Electronic databases were searched for RCTs assessing the effect of at least one non-pharmacological intervention (any form of exercise and/or supplementation with protein, vitamin D, calcium or creatine) on any musculoskeletal measure/outcome of interest (BMD, bone strength/turnover, muscle mass and strength, physical performance, falls/fractures) in adults with osteosarcopenia as defined by any proposed criteria.

RESULTS

Two RCTs (of n=106 older osteosarcopenic adults (≥65 years)) assessing the effects of progressive resistance training (RT) (via resistance bands or machines; 2-3 times/week; ~60 minutes in duration) were eligible for inclusion. The two RCTs demonstrated moderate quality evidence that RT increases muscle mass, strength, and quality, with changes in strength and quality occurring before muscle mass (12 vs 28 weeks). There was low quality evidence that RT increases lumbar spine BMD and maintains total hip BMD when performed for 12 and 18 months, respectively, and moderate quality evidence that RT has no effect on markers of bone turnover or physical performance. No major adverse effects were recorded in either of the RCTs. There were no eligible RCTs examining the impact of nutritional interventions.

CONCLUSION

Chronic RT is safe and effective at potentiating gains in muscle mass, strength, and quality, and increasing or maintaining BMD in older osteosarcopenic adults. No RCT has examined the effects of protein, vitamin D, calcium, or creatine against a control/placebo in this high-risk population.

International Exercise Recommendations in Older Adults (ICFSR): Expert Consensus Guidelines

The human ageing process is universal, ubiquitous and inevitable. Every physiological function is being continuously diminished. There is a range between two distinct phenotypes of ageing, shaped by patterns of living - experiences and behaviours, and in particular by the presence or absence of physical activity (PA) and structured exercise (i.e., a sedentary lifestyle). Ageing and a sedentary lifestyle are associated with declines in muscle function and cardiorespiratory fitness, resulting in an impaired capacity to perform daily activities and maintain independent functioning. However, in the presence of adequate exercise/PA these changes in muscular and aerobic capacity with age are substantially attenuated. Additionally, both structured exercise and overall PA play important roles as preventive strategies for many chronic diseases, including cardiovascular disease, stroke, diabetes, osteoporosis, and obesity; improvement of mobility, mental health, and quality of life; and reduction in mortality, among other benefits. Notably, exercise intervention programmes improve the hallmarks of frailty (low body mass, strength, mobility, PA level, energy) and cognition, thus optimising functional capacity during ageing. In these pathological conditions exercise is used as a therapeutic agent and follows the precepts of identifying the cause of a disease and then using an agent in an evidence-based dose to eliminate or moderate the disease. Prescription of PA/structured exercise should therefore be based on the intended outcome (e.g., primary prevention, improvement in fitness or functional status or disease treatment), and individualised, adjusted and controlled like any other medical treatment. In addition, in line with other therapeutic agents, exercise shows a dose-response effect and can be individualised using different modalities, volumes and/or intensities as appropriate to the health state or medical condition. Importantly, exercise therapy is often directed at several physiological systems simultaneously, rather than targeted to a single outcome as is generally the case with pharmacological approaches to disease management. There are diseases for which exercise is an alternative to pharmacological treatment (such as depression), thus contributing to the goal of deprescribing of potentially inappropriate medications (PIMS). There are other conditions where no effective drug therapy is currently available (such as sarcopenia or dementia), where it may serve a primary role in prevention and treatment. Therefore, this consensus statement provides an evidence-based rationale for using exercise and PA for health promotion and disease prevention and treatment in older adults. Exercise prescription is discussed in terms of the specific modalities and doses that have been studied in randomised controlled trials for their effectiveness in attenuating physiological changes of ageing, disease prevention, and/or improvement of older adults with chronic disease and disability. Recommendations are proposed to bridge gaps in the current literature and to optimise the use of exercise/PA both as a preventative medicine and as a therapeutic agent.

The effects of parasitism on ewes for prime lamb production in western Victoria

Context Internal parasites are estimated to cost the Australian sheep industry AUD436 million per annum (p.a.). Aims To assess the effects of parasitism in flocks producing prime lambs in the 500–700 mm p.a rainfall. area of Victoria. Methods Ewes on two farms that followed ‘best practice’ gastrointestinal parasite control programs (BP) and two farms that did not (regionally typical, TYP) were compared. Separate cohorts of ewes were monitored from pregnancy scanning to their subsequent joining each year for three consecutive seasons. Observations included worm egg count (WEC), bodyweight, condition score and presence of breech soiling (dag). These were compared between groups that were treated to suppress parasitism (SUP) and those treated according to the usual program used on that farm (NSUP). Data from individual ewes were analysed using a multivariable, mixed-effects regression model. Key results After adjusting for known confounders, SUP ewes were 1.2 (95% CI 0.80–1.6) kg heavier than NSUP ewes. Mature SUP ewes were significantly heavier than NSUP ewes at their next joining on 6 of 18 occasions, mostly following winters when ewes experienced nutritional stress. Ewe hoggets and Merino ewes were generally more susceptible to parasitism than mature non-Merino ewes; single-bearing ewes were less susceptible than those bearing twins. The effects of parasitism were reduced when peri-parturient ewes had an optimal condition score and grazed adequate pastures. Conclusions Ewes were more vulnerable to parasitism when immature, twin-bearing, or under nutritional stress. Some of the greatest differences between SUP and NSUP ewes occurred following periods of low feed availability and/or ewe condition score. The difference between the mean bodyweight of SUP and NSUP Merinos was not always greater than that of the non-Merinos. WECs are not a sole reliable indicator of the effects of parasitism in this class of sheep. Implications Immature or twin-bearing ewes, and those in suboptimal body condition, should be managed considering their increased vulnerability to parasitism, and WEC interpreted alongside other factors. Controlled release capsules were not cost effective in reducing production loss from gastrointestinal nematodes in most years but may be effective in reducing the effects of clinical parasitism in some cases.

Cytoskeletal regulation of synaptogenesis in a model of human fetal brain development

Excitatory synapse formation begins in mid-fetal gestation. However, due to our inability to image fetal synaptogenesis, the initial formation of synapses remains understudied. The recent development of human fetal brain spheroids provides access to this critical period of synapse formation. Using human neurons and brain spheroids, we address how altered actin regulation impacts the formation of excitatory synapses during fetal brain development. Prior to synapse formation, inhibition of RhoA kinase (ROCK) signaling promotes neurite elongation and branching. In addition to increasing neural complexity, ROCK inhibition increases the length of protrusions along the neurite, ultimately promoting excitatory synapse formation in human cortical brain spheroids. A corresponding increase in Rac1-driven actin polymerization drives this increase in excitatory synaptogenesis. Using STORM super-resolution microscopy, we demonstrate that actomyosin regulators, including the Rac1 regulator, α-PIX, and the RhoA regulator, p115-RhoGEF, localize to nascent excitatory synapses, where they preferentially localize to postsynaptic compartments. These results demonstrate that coordinated RhoGTPase activities underlie the initial formation of excitatory synapses and identify critical cytoskeletal regulators of early synaptogenic events.

Variety, Price, and Consumer Desirability of Fresh Fruits and Vegetables in 7 Cities around the World

Few studies have attempted to quantify the variety, price, and consumer desirability of fruits and vegetables (F&Vs) across a diversity of cities. We implemented a market basket survey of F&Vs from December 2018 to February 2019 in middle-income neighborhoods of the following cities: Visakhapatnam, India; Kathmandu, Nepal; Addis Ababa, Ethiopia; Dar es Salaam, Tanzania; Mexico City, Mexico; Bangkok, Thailand; and Brookline, United States. The total variety of fruits ranged from 4.1 in Visakhapatnam to 17.3 in Brookline, and of vegetables from 6.1 in Dar es Salaam to 20.3 in Brookline. Of the 3 fruits for which price data were collected, apples tended to be the most expensive, and bananas the least expensive. For vegetables, capsicum tended to be the most expensive and eggplants the least expensive. Tablet-based market basket surveys are a useful tool for evaluating food environments. These pilot data provide further evidence of the homogenization of global diets.

Failure of non-vacuum steam sterilization processes for dental handpieces

BACKGROUND

Dental handpieces are used in critical and semi-critical operative interventions. Although some dental professional bodies recommend that dental handpieces are sterilized between patient use there is a lack of clarity and understanding of the effectiveness of different steam sterilization processes. The internal mechanisms of dental handpieces contain narrow lumens (0.8-2.3 mm) which can impede the removal of air and ingress of saturated steam required to achieve sterilization conditions.

AIM

To identify the extent of sterilization failure in dental handpieces using a non-vacuum process.

METHODS

In-vitro and in-vivo investigations were conducted on widely used UK bench-top steam sterilizers and three different types of dental handpieces. The sterilization process was monitored inside the lumens of dental handpieces using thermometric (TM; dataloggers), chemical indicator (CI), and biological indicator (BI) methods.

FINDINGS

All three methods of assessing achievement of sterility within dental handpieces that had been exposed to non-vacuum sterilization conditions demonstrated a significant number of failures [CI: 8/3024 (fails/no. of tests); BI: 15/3024; TM: 56/56] compared to vacuum sterilization conditions (CI: 2/1944; BI: 0/1944; TM: 0/36). The dental handpiece most likely to fail sterilization in the non-vacuum process was the surgical handpiece. Non-vacuum sterilizers located in general dental practice had a higher rate of sterilization failure (CI: 25/1620; BI: 32/1620; TM: 56/56) with no failures in vacuum process.

CONCLUSION

Non-vacuum downward/gravity displacement, type N steam sterilizers are an unreliable method for sterilization of dental handpieces in general dental practice. The handpiece most likely to fail sterilization is the type most frequently used for surgical interventions.

Revised standards for sterilisation: the changes

The standards for the three main methods of sterilising medical devices, ethylene oxide, radiation and moist heat, have been revised. This article discusses the major changes in the requirements, which will need to be addressed to demonstrate compliance with the revised standards.

Motorcycling freedom: a paraplegics dream

People with disabilities have the same rights as other members of society in directing and implementing the decisions which affect their lives, although it is not always afforded them due to physical limitations. A chance encounter by the author, a University of Western Australia mechanical engineering student, with a paraplegic man who expressed his dream of being able to ride a motorcycle again led to the design and build of a specially modified motorcycle that could be ridden safely and comfortably by a person without the use of their legs. The prototype involved several modifications which allow it to be ridden by a paraplegic person. They included, a thumb controlled pneumatic gear shifter, an integrated front and rear brake actuated with a single hand lever, ergonomic supports to hold the riders legs in place and an automatic stabilising system to balance the motorcycle at low speeds. The benefits that result from the inclusion of people with disabilities into regular leisure activities include normalisation as well as a sense of independence and freedom for the individual. It also allowed one man the chance to reach for his dreams.

Collisionally processed rocks on mars

The Pathfinder landing site on Mars has boulders that may be cratered (Stimpy), split (Chimp), fragmented (Book End and Flat Top), or otherwise partly destroyed (Yogi and Frog) by collisional processes. Atmospheric-entry calculations show that centimeter-sized projectiles survive passage through the martian atmosphere and encounter the surface of Mars at velocities of a few kilometers per second. Craters less than 1 meter in diameter may contribute to the evolution of the martian surface and its soils.

Disruption of a coronary stent during atherectomy for restenosis

Directional coronary atherectomy is being used in the treatment of atherosclerotic lesions in coronary vessels and vein grafts. This report describes the use of atherectomy for the treatment of restenosis of a coronary stent. The procedure was complicated by disruption of the stent which was snared by the atherectomy cutter.

Bone marrow hypoplasia during intensive care: bone marrow culture studies implicating ranitidine in the suppression of haemopoiesis

Two seriously ill patients with renal failure developed bone marrow hypoplasia and peripheral blood cytopenias during admission to an Intensive Care Unit (ICU). Both patients were being treated with ranitidine and, in both, there was evidence of drug accumulation. Serum from the patient with the highest concentration of ranitidine inhibited granulocyte-macrophage colony growth from normal bone marrow. The addition of ranitidine to cultures of normal bone marrow also produced a concentration-dependent inhibition of colony growth. Ranitidine should be used with caution in patients with renal failure where drug accumulation may seriously impair bone marrow function.

Six-member stimulus classes generated by conditional-discrimination procedures

In conditional-discrimination procedures with three sets of stimuli, A, B, and C, three stimuli per set (A1A2A3, B1B2B3, and C1C2C3), subjects (children and adults) learned to select Set-B and Set-C comparisons conditionally upon Set-A samples (A1B1, A1C1, A2B2, A2C2, A3B3, A3C3). If the conditional-discrimination procedures also generated equivalence relations, three 3-member stimulus classes would be demonstrable, A1B1C1, A2B2C2, and A3B3C3. In addition to these three sets, the present experiments used three other sets of stimuli--D, E, and F. The subjects learned to select Set-E and Set-F comparisons conditionally upon Set-D samples (D1E1, D1F1, D2E2, D2F2, D3E3, D3F3). This established a second group of three 3-member stimulus classes, D1E1F1, D2E2F2, and D3E3F3. In all, two groups of three 3-member classes were established by teaching subjects 12 conditional discriminations. The two groups of 3-member classes were then combined (successfully for 5 of 8 subjects) into a single group of three 6-member classes by teaching the subjects three more conditional relations (E1C1, E2C2, and E3C3). With three other children, enlarging the classes one member at a time also produced 6-member classes. As a consequence of class formation, 60 untrained conditional relations emerged from 15 that had been explicitly taught. Six of the subjects also proved capable of naming the stimuli consistently in accord with their class membership, but two subjects demonstrated class formation even in the absence of consistent naming.

Gas exchange during ventilator treatment: a validation of a computerized technique and its comparison with the Douglas bag method

In recent years a number of commercial instruments for on-line gas exchange measurements has been introduced. One of them, the Engström Metabolic Computer (EMC), is here clinically validated as compared to the standard Douglas bag method for gas sampling and a Centronic Mass Spectrometer (CMS) for gas analysis. VO2, VCO2 and RQ were simultaneously measured and calculated with both methods. Twenty individual gas exchange determinations were made at different times on 12 critically ill patients at the intensive care unit. There was a small but significant difference (P less than 0.025) of 4.3% +/- 8.4% (s.d.) between the two methods when they were used to measure VO2 (the EMC giving the lower value). The corresponding value of VCO2 was 2.4% +/- 9.1% (s.d.), and for RQ the difference was -1.98% +/- 7.1% (s.d.). These differences are not significant at the 95% level of significance. Determinations of oxygen uptake during ventilator treatment with standard methods usually involve technical difficulties and are associated with errors of method around 10%. Our results indicate a probable error of about 8.5% for VO2 in clinical situations. Considering the difficulties involved in determinations of gas exchange, the EMC method seems to be a valuable technique with an accuracy within acceptable limits.

Comparison of respirable dust specifications with recent lung data

This paper compares the two major respirable dusts size specifications with lung models derived from a recent review using computer simulation in logarithmic normal dust clouds. It was found that either specification gives reasonable reproductibility with respect to either the nose or mouth breathing lung models over the usual range of industrial dust clouds, and either could be chosen as a standard with only a slight adjustment in the corresponding dust control limit.

Evaluation of a prototype micro-electronic autoclave cycle integrator

Instability and non-uniformity of spore preparations and the non-conformity of chemical indicators to the temperature coefficients of spore inactivation are problems associated with current methods of autoclave cycle monitoring. A prototype micro-electronic instrument, which largely overcomes these problems, is described. It monitors autoclave cycles in terms of the integral F0 and Nabla functions. Its thermometric and integrating accuracy is demonstrated. A discussion of the problems associated with the use of sensitive electronic instruments in the autoclave room environment reveals the need for independent monitoring areas when such devices are used. Inactivation constants were determined for spores of the organism Bacillus stearothermophilus, NCTC 10 003 and were described using D115 (12.0 min) and Z (9.0 degrees C) values and the first order reaction Arrhenius constants A 10(41.2) min-1) and Ea (74.4 kcal mol-1, 311 kJ mol-1). These have been compared with recently published values. The standardization of F0 and Nabla is discussed with reference to the setting of minimum values related to product bioburden and maximum values related to an acceptable degree of product degradation.

A canine model for reaginic hypersensitivity and allergic bronchoconstriction

Immunization of neonatal dogs with a conjugate of 2,4-dinitrobenzene and ovalbumin (DNP2-OA), using aluminum hydroxide as the adjuvant, elicited long-lasting (over 30 wk) anti-DNP and anti-OA IgE antibody responses of high titers as determined by homologous passive cutaneous anaphylaxis. Low antigen doses of 10 or 50 mug were more effective than the higher doses of 250 or 1,250 mug in inducing high IgE antibody levels. However, this method of immunization failed to elicity any detectable IgE antibody response in adult dogs. Bronchoprovocation with antigen of sensitized animals having IgE antibody titers in excess of 64 resulted in a marked increase in airflow resistance, which could be corrected by the administration of nebulized isoproterenol. On the other hand, sensitized animals with IgE antibody titers in the order of 64 did not manifest significant bronchoconstriction on inhalation challenge but developed anaphylaxis following intravenous injection of the antigen.

Blast crisis of chronic myeloid leukaemia (CML). I. Presentation simulating acute lymphoid leukaemia (ALL)

Seven patients presenting as an acute leukaemia caused difficulty in diagnosis. The lymphoid appearance of the balst cells either initially or during treatment suggested acute lymphoid leukaemia (ALL). In each case the Philadelphia chromosome was shown to be present thus suggesting that these cases were examples of chronic myeloid leukaemia (CML) presenting in blast crisis without a detectable chronic phase. The implications of these findings are discussed and the difficulty in achieving a precise diagnosis in the acute leukaemias is emphasised. Cytogenetic analysis should be carried out whenever the type of acute leukaemia present is of critical importance.

Blast crisis of chronic myeloid leukaemia (CML). II. Cell surface marker analysis of "lymphoid" and myeloid cases

Fourteen cases of philadelphia chromosome (Ph1) positive chronic myeloid leukaemia in blast transformation have been investigated using cell surface markers. Morphologically eight cases were lymphoid and the remainder myeloid in appearance. All cases were negative with surface markers for thymocytes and T and B lymphocytes. Five of the lymphoid cases reacted with an antiserum specific for acute lymphoid leukaemia )ALL) of non-T non-B type and were also weakly reactive with a lymphocyte reactive antiserum. A sixth patient, whose blast cells were anti-ALL negative (ALL-) at presentation, subsequently developed central nervous system leukaemia with anti-ALL positive (ALL+) blast cells in the CSF. In all cases the leukaemic blast cells showed greatly diminished expression of cholera toxin receptors when compared to granulocytic cells from the chronic phase of CML. This parallels weak or negligible expression of the cholera toxin receptor in ALL and AML. These results suggest that the blastic phase of CML may involve different cellular derivatives of a pluripotential stem cell in which the primary malignant/genetic changes reside. The blast crisis of CML can therefore be heterogeneous with respect to cellular expression and in a significant proportion of patients involves a cell which is by membrane markers and morphological criteria indistinguishable from that seen in the common form of ALL. In these cases the Philadelphia chromosome may be the only distinguishing cellular characteristic.

Blast crisis of chronic myeloid leukaemia: the effect of intensive chemotherapy

24 patients with Philadelphia chromosome positive chronic myeloid leukaemia (CML) in blast crisis were treated with intensive chemotherapy. 16 patients showed either partial or complete response to this treatment, but median survival remained short (13 weeks), and much of this time was spent in hospital. These results were not significantly better than those obtained by others using vincristine and prednisolone alone, and this combination of drugs can often be given on an outpatient basis. It is concluded that until more effective intensive therapy becomes available patients in CML blast crisis should be managed in such a way that the quality of life is not impaired; and that at present vincristine and prednisolone appears to be the most impaired; and that at present vincristine and prednisolone appears to be the most appropriate initial treatment, though even this is far from satisfactory.