Primary Care Physicians' and Hospitalists' Experience with Advance Care Planning with South Asian Canadian Older Adults before and during COVID-19

Few older adults discuss their end-of-life care wishes with their physician, and even fewer minorities do this. We explored physicians' experience with advance care planning (ACP) including the barriers/facilitating factors encountered when initiating/conducting ACP discussions with South Asians (SA), one of Canada's largest minorities. Eleven primary care physicians (PC) and 11 hospitalists with ≥ 15 per cent SA patients ≥ 55 years of age were interviewed: 10 in 2020, 12 in 2021. Thematic analysis of transcripts indicated that cultural and communication barriers, physician's specialization, SA older adults' lack of ACP awareness, and decision-making deference to family and physicians were barriers to ACP discussions. Although the COVID-19 pandemic impacted physicians' practices, contrary to our hypothesis most reported no change in frequency of ACP discussions. Although ACP discussions were viewed as best conducted by PC physicians, only 55 per cent had ACP training and only 64 per cent had used ACP tools. Training in ACP facilitation, concerning ACP tool usage, and training in patient-physician communication are recommended.

Feasibility of a Virtual Health-Promoting Intervention (Choose to Move) for Older Adults: A Rapid Adaptation in Response to COVID-19

To support older adults during the first wave of COVID-19, we rapidly adapted our effective health-promoting intervention (Choose to Move [CTM]) for virtual delivery in British Columbia, Canada. The intervention was delivered (April-October 2020) to 33 groups of older adults ("programs") who were a convenience sample (had previously completed CTM in person; n = 153; 86% female; 73 [6] years). We compared implementation outcomes (recruitment, dose received, retention, and completion of virtual data collection) to predetermined feasibility targets. We assessed mobility, physical activity, and social health outcomes pre- and postintervention (3 months) with validated surveys. We met most (dose received, retention, and virtual data collection), but not all (recruitment), feasibility targets. Approximately two thirds of older adults maintained or improved mobility, physical activity, and social health outcomes at 3 months. It was feasible to implement and evaluate CTM virtually. In future, virtual CTM could help us reach homebound older adults and/or serve as support during public health emergencies.

Life-space mobility and healthcare costs and utilization in older men

OBJECTIVES

To determine the association of life-space score with subsequent healthcare costs and utilization.

DESIGN

Prospective cohort study (Osteoporotic Fracture in Men [MrOS]).

SETTING

Six U.S. sites.

PARTICIPANTS

A total of 1555 community-dwelling men (mean age 79.3 years; 91.5% white, non-Hispanic) participating in the MrOS Year 7 (Y7) examination linked with their Medicare claims data.

MEASUREMENTS

Life-space during the past month was assessed as 0 (daily restriction to one's bedroom) to 120 (daily trips outside one's town without assistance) and categorized (0-40, 41-60, 61-80, 81-100, 101-120). Total annualized direct healthcare costs and utilization were ascertained during 36 months after the Y7 examination.

RESULTS

Mean total annualized costs (2020 U.S. dollars) steadily increased across category of life-space score, from $7954 (standard deviation [SD] 16,576) among men with life-space scores of 101-120 to $26,430 (SD 28,433) among men with life-space scores of 0-40 (p < 0.001). After adjustment for demographics, men with a life-space score of 0-40 versus men with a life-space score of 101-120 had greater mean total costs (cost ratio [CR] = 2.52; 95% confidence interval [CI] = 1.84-3.45) and greater risk of subsequent hospitalization (odds ratio [OR] 4.72, 95% CI 2.61-8.53) and skilled nursing facility (SNF) stay (OR 7.32, 95% CI 3.65-14.66). Life-space score was no longer significantly associated with total healthcare costs (CR for 0-40 vs 101-120 1.29; 95% CI 0.91-1.84) and hospitalization (OR 1.76, 95% CI 0.89-3.51) after simultaneous consideration of demographics, medical factors, self-reported health and function, and the frailty phenotype; the association of life-space with SNF stay remained significant (OR 2.86, 95% CI 1.26-6.49).

CONCLUSION

Our results highlight the importance of function and mobility in predicting future healthcare costs and suggest the simple and convenient life-space score may in part capture risks from major geriatric domains and improve identification of older, community-dwelling men likely to require costly care.

THE SAFEST REVIEW: THE SHOCK-ABSORBING FLOORING EFFECTIVENESS SYSTEMATIC REVIEW IN CARE SETTINGS

Falls in hospitals and care homes are a major issue of international concern. Falls cost the US $34 billion a year, with injurious falls being particularly life-limiting and costly. Shock-absorbing flooring decreases the stiffness of the ground surface to reduce the impact of a fall. There is a growing body of evidence on flooring for fall-related injury prevention, however no systematic review exists to inform practice. We systematically reviewed the evidence on the clinical and cost-effectiveness of shock-absorbing flooring use for fall-related injury prevention in care settings. We searched six databases, clinical trial registries, conference proceedings, theses/dissertations, websites, reference lists, conducted forward citation searches, and liaised with experts in the field. We conducted study selection, data collection, and critical appraisal independently in duplicate. We evaluated the influence of shock-absorbing flooring on fall-related injuries, falls, and staff work-related injuries. We adopted a mixed methods approach considering evidence from randomised, non-randomised, economic, qualitative, and implementation studies. We assessed and reported the quality of outcomes using the GRADE approach and Summary of Findings Tables. This review, conducted over the course of 2019, summarises the certainty of the evidence on whether and which shock-absorbing floors influence injuries from falls, the chance of someone falling over, and work-related injuries in staff (e.g. from manoeuvring equipment across softer floors). Our findings are applicable to health and social care professionals, buildings and facilities managers, carers, older adults, architects, and designers. Funded by National Institute for Health Research, Health Technology Assessment (ref 17/148/11); registered in PROSPERO (CRD42019118834).

Modelling random antibody adsorption and immunoassay activity

One of the primary considerations in immunoassay design is optimizing the concentration of capture antibody in order to achieve maximal antigen binding and, subsequently, improved sensitivity and limit of detection. Many immunoassay technologies involve immobilization of the antibody to solid surfaces. Antibodies are large molecules in which the position and accessibility of the antigen-binding site depend on their orientation and packing density. In this paper we propose a simple mathematical model, based on the theory known as random sequential adsorption (RSA), in order to calculate how the concentration of correctly oriented antibodies (active site exposed for subsequent reactions) evolves during the deposition process. It has been suggested by experimental studies that high concentrations will decrease assay performance, due to molecule denaturation and obstruction of active binding sites. However, crowding of antibodies can also have the opposite effect by favouring upright orientations. A specific aim of our model is to predict which of these competing effects prevails under different experimental conditions and study the existence of an optimal coverage, which yields the maximum expected concentration of active particles (and hence the highest signal).

Patient's experience with subcutaneous and oral methotrexate for the treatment of rheumatoid arthritis

Background

Despite the prominent position of methotrexate (MTX) in Rheumatoid Arthiris (RA) therapeutics, its real-world effectiveness may be influenced by a relative lack of tolerability or other side effects that physicians may not be aware of but that are bothersome to patients.

The aim of this study is to identify suboptimal patient experience with MTX and to raise awareness for clinicians to identify opportunities to mitigate bothersome symptoms and side effects and optimize response to MTX.

Methods

We conducted a prospective, cross-sectional, online survey among RA patients who were members of Creakyjoints, a large arthritis patient community. Eligible participants must have recently initiated a new biologic, subcutaneous (SQ) MTX, or oral MTX in the last 12 months and were uniquely assigned to one of these 3 groups. Descriptive statistics were used to compare patient-reported side effects and tolerability related to MTX use in the 3 medication groups (SQ MTX, oral MTX, and biologic).

Results

A total of 382 (85 %) of 448 eligible patients completed the survey and were grouped as: biologic (n = 218), SQ MTX (n = 49), and oral MTX (n = 115). Demographics were mean standard deviation (SD) age 48 (10) years, 92 % white, 91 % women. Symptoms significantly more prevalent in the SQ and oral MTX groups included diarrhea, fatigue, malaise, and hair loss. Injection related pain was lower with SQ MTX compared to SQ biologics. Out of a total of 8 potential symptoms and side effects examined, higher dose MTX (> = 20 mg/week) was associated with a 2.26 (1.25–4.09) greater likelihood of more side effects referent to < =10 mg/week.

Conclusion

Results from this real-world RA patient cohort suggest that MTX is accompanied by many patient-reported side effects and tolerability problems that may be under-recognized by physicians. These may impact both treatment satisfaction and medication adherence.

Statins and physical activity in older men: the osteoporotic fractures in men study

IMPORTANCE

Muscle pain, fatigue, and weakness are common adverse effects of statin medications and may decrease physical activity in older men.

OBJECTIVE

To determine whether statin use is associated with physical activity, longitudinally and cross-sectionally.

DESIGN, SETTING, AND PARTICIPANTS

Men participating in the Osteoporotic Fractures in Men Study (N = 5994), a multicenter prospective cohort study of community-living men 65 years and older, enrolled between March 2000 and April 2002. Follow-up was conducted through 2009.

EXPOSURES

Statin use as determined by an inventory of medications (taken within the last 30 days). In cross-sectional analyses (n = 4137), statin use categories were users and nonusers. In longitudinal analyses (n = 3039), categories were prevalent users (baseline use and throughout the study), new users (initiated use during the study), and nonusers (never used).

MAIN OUTCOMES AND MEASURES

Self-reported physical activity at baseline and 2 follow-up visits using the Physical Activity Scale for the Elderly (PASE). At the third visit, an accelerometer measured metabolic equivalents (METs [kilocalories per kilogram per hour]) and minutes of moderate activity (METs ≥3.0), vigorous activity (METs ≥6.0), and sedentary behavior (METs ≤1.5).

RESULTS

At baseline, 989 men (24%) were users and 3148 (76%) were nonusers. The adjusted difference in baseline PASE between users and nonusers was -5.8 points (95% CI, -10.9 to -0.7 points). A total of 3039 men met the inclusion criteria for longitudinal analysis: 727 (24%) prevalent users, 845 (28%) new users, and 1467 (48%) nonusers. PASE score declined by a mean (95% CI) of 2.5 (2.0 to 3.0) points per year for nonusers and 2.8 (2.1 to 3.5) points per year for prevalent users, a nonstatistical difference (0.3 [-0.5 to 1.0] points). For new users, annual PASE score declined at a faster rate than nonusers (difference of 0.9 [95% CI, 0.1 to 1.7] points). A total of 3071 men had adequate accelerometry data, 1542 (50%) were statin users. Statin users expended less METs (0.03 [95% CI, 0.02-0.04] METs less) and engaged in less moderate physical activity (5.4 [95% CI, 1.9-8.8] fewer minutes per day), less vigorous activity (0.6 [95% CI, 0.1-1.1] fewer minutes per day), and more sedentary behavior (7.6 [95% CI, 2.6-12.4] greater minutes per day).

CONCLUSIONS AND RELEVANCE

Statin use was associated with modestly lower physical activity among community-living men, even after accounting for medical history and other potentially confounding factors. The clinical significance of these findings deserves further investigation.

Hospitalization and change in body composition and strength in a population-based cohort of older persons

OBJECTIVES

To examine the association between hospitalization and annual changes in body composition and strength in older adults.

DESIGN

Cohort study.

SETTING

Clinic examinations in Pittsburgh, Pennsylvania, or Memphis, Tennessee.

PARTICIPANTS

Well-functioning adults aged 70 to 79 who participated in the Health, Aging and Body Composition Study.

MEASUREMENTS

Hospitalizations were reported at annual clinic visits and in semiannual phone interviews. In the event of death or reported hospitalization, hospitalizations were adjudicated according to medical record review. Dual X-ray absorptiometry (DXA) assessments of total, lean, and fat mass were conducted in six annual examinations, and measures of knee extensor strength were conducted in two annual examinations.

RESULTS

DXA assessments followed 2,309 hospitalizations. In men and women, hospitalization in the previous year was associated with greater declines in total mass (-0.76 and -0.81 kg, respectively), fat mass (-0.41 and -0.54 kg), and lean mass (-0.33 and -0.25 kg) (P < .001 for all) than in nonhospitalized participants, after adjustment for demographics and baseline values. Hospitalization was associated with strength declines in men (-4.02 Nm, P = .046) but not in women. Relationships were similar after adjusting for health behaviors and chronic conditions, although the association between hospitalization and strength was attenuated. Associations increased with number of days hospitalized; hospitalizations totaling 8 days or more in the previous year were associated with significantly greater loss of total, lean, and fat mass and loss of strength in both sexes than in nonhospitalized participants.

CONCLUSION

Hospitalization is associated with significant changes in body composition and strength in older persons. These effects appear particularly important in persons hospitalized for 8 or more days per year.

Analysis of Topoisomerase IIa and HER2 Status in 126 Patients from the US Oncology 9735 Trial of Adjuvant Chemotherapy with Docetaxel/Cyclophosphamide (TC) vs Doxorubicin/Cyclophosphamide (AC) in Early Breast Cancer

Background: HER2/neu (HER2) positive breast cancers are associated with worse survival, resistance to cyclophosphamide/methotrexate/fluorouracil, and hypothesized to be sensitive to anthracyclines. It has been postulated that only a subset of HER2 positive breast cancers are sensitive to anthracyclines. Investigators have been working on how to identify this subset of patients, thus sparing patients from anthracyclines that have potential cardiac and bone marrow toxicities. Overexpression of the topoisomerase IIa gene (TOP2A) is the putative biomarker for sensitivity to anthracyclines. Testing tumors for overexpression of this gene may help identify patients who will not benefit from anthracylines. TOP2A is located in the same amplicon as the HER2 gene and can be assessed for overexpression by a FISH assay.Materials and Methods: Paraffin tissue blocks were obtained in 126 patients entered on US Oncology trial 9735 which recruited patients between 1997 and 2000. Data on HER2 status and outcome was previously reported (JCO 27:1177-1183, 2009). TOP2A status was then assessed by fluorescent in situ hybridization (FISH) using the LSI TOP2A Spectrum Orange Probe (Vysis). A total of 20 cells were counted and a gene ratio of greater than 2.0 was considered positive. Clinical data and outcome were available for statistical analysis.Results: We found that none of the 97 HER2 negative cases demonstrated overexpression of TOP2A by FISH analysis. TOP2A was overexpressed in 43% of the 29 HER2 positive cases. An analysis of outcome will be presented at the meeting, although the number of cases limits this observation.Discussion: Our study supports the observation that TOP2A is not overexpressed in HER2 negative disease and is only observed in a subset of cancers overexpressing HER2. Clinical correlation of outcome will be necessary to confirm whether or not TOP2A is a reliable biomarker of sensitivity to anthracyclines. The ongoing US Oncology trial of TC vs. TAC in HER2 negative breast cancer (USOR Trial 06-090) should provide that evidence.Supported in part by a grant from sanofi-aventis.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2134.

Scintigraphic measurement of tracheal mucus velocity in vivo

Mucociliary clearance (MCC) is an important mechanism for removing inhaled particles, secretions and cellular debris from the respiratory tract. Here, a direct measurement of tracheal mucus velocity (TMV) for assessment of MCC, suitable for clinical and research use, is reported, and a comparison is made of TMV in normal subjects and patients with chronic obstructive pulmonary disease (COPD). A 0.1-mL bolus of radiolabelled (2-5 MBq), technetium-labelled macroaggregated human albumin (99mTc MAA) was injected through the cricothyroid membrane into the trachea of 20 young (< 50 yrs) and 12 older (> 50 yrs) normal subjects and 34 patients with COPD. Repeat studies were carried out in 13 normal subjects and 16 COPD patients. Movement of the bolus in the trachea was recorded (15 min) using a gamma camera interfaced to a computer. Data were analysed using specifically designed software. The test was well tolerated by subjects and patients, and no significant adverse events were reported. No significant differences were observed between data recorded from different regions of the bolus (leading edge, peak, trailing edge) by analysis of variance (ANOVA). Bland-Altman plots of the repeat studies indicated that data were more variable in normal subjects (coefficient of repeatability (COR) 10.3 mm.min-1) than in COPD patients (COR 5.5 mm.min-1). TMV (mean +/- SD) in young normal subjects (n = 20) was 10.7 +/- 3.5 mm.min-1. TMV was reduced in older normal subjects (n = 12; 6.5 +/- 2.6 mm.min-1) and further reduced in COPD (n = 34; 2.1 +/- 2.7 mm.min-1). In conclusion, this technique can be used to measure tracheal mucus velocity rapidly and safely in healthy subjects and patients with respiratory tract disease. This study has confirmed that tracheal mucus velocity declines with age and is further impaired in patients with chronic obstructive pulmonary disease.

Reproductive management of postpartum cows

High reproductive efficiency in the dairy cow requires a disease-free transition period, high submission rates to AI and high pregnancy rates per service. A key risk factor that causes increased incidence of metabolic disease is low negative energy balance (NEB) in the periparturient and early postpartum periods. Low NEB decreases LH pulse frequency, growth rate and diameter of dominant follicle (DF), IGF-I, glucose, insulin concentrations and increases GH and certain blood metabolites; these effects result in greater loss of body condition score (BCS) and a higher percent of anoestrous cows in the herd. It is important to decrease the incidence of metabolic disease by achieving high dry matter intake (DMI) and minimising the period of NEB after calving. Thus, nutritional management of the cow in the transition period has a crucial role to play in improving reproductive efficiency, because acute nutritional deprivation of heifers has immediate deleterious effects on follicular growth and ovulation. To obtain high submission rates, it is necessary to decrease the incidence of anoestrus and to have good oestrous detection rates. Pregnancy rates per service are affected by a variety of factors. NEB can have deleterious effects on the follicle or the corpus luteum (CL) by decreasing IGF-I concentrations and steroidogenesis. High protein diets fed to postpartum cows leads to increased blood urea and lower fertility. Although the mechanism is not clear, the practical implication of feeding the appropriate level of crude protein in the diet is clear. Thus, a coordinated management approach involving herd managers, nutritionists and veterinarians is required to obtain high reproduction efficiency in dairy cows.

The linking regions of EBNA1 are essential for its support of replication and transcription

The ability of distant cis-acting DNA elements to interact functionally has been proposed to be mediated by the interaction of proteins associated site specifically with those cis-acting elements. We have found that the DNA-linking regions of EBNA1 are essential for its contribution to both replication and transcription. The synthesis of plasmids containing the Epstein-Barr virus (EBV) origin of plasmid replication (oriP) can be mediated entirely by the cellular machinery; however, the replicated molecules are lost rapidly from proliferating cells. When EBNA1 is provided in trans, plasmids containing oriP (oriP plasmids) are synthesized during repeated S phases, and the newly formed daughter molecules are precisely segregated to the daughter cells. The contribution(s) of EBNA1 to the stable replication of oriP plasmids is therefore likely to be postsynthetic. In latently infected cells, EBNA1 also regulates the expression of multiple EBV promoters located as many as 10 kbp away. EBNA1 supports replication and transcription through binding to oriP; both the ability of EBNA1 to bind to DNA and the integrity of its binding sites in oriP are required. However, DNA binding by EBNA1 is not sufficient to support replication or transcription, indicating that an additional activity (or activities) is required. EBNA1 links DNAs to which it binds and can form a loop between the two subelements of oriP, the family of repeats and the region of dyad symmetry, each of which contains multiple binding sites for EBNA1. We have constructed a set of derivatives of EBNA1 which contain both, one, or neither of its linking regions in various contexts. Analyses of these derivatives demonstrate that the linking regions of EBNA1 are essential for its support of replication and transcription and that the ability of derivatives of EBNA1 to link DNAs correlates strongly with their support of these activities in cells. These findings indicate that protein-protein associations of the linking regions of EBNA1 underlie its long-range contributions to replication and transcription.

Studies on the mechanism of DNA linking by Epstein-Barr virus nuclear antigen 1

Epstein-Barr virus nuclear antigen 1 (EBNA1) can both bind to and link DNA. Dimers of EBNA1 bind specific sites, two clusters of which, the FR and DS, comprise the necessary cis-acting elements of the Epstein-Barr viral origin of plasmid replication. EBNA1-dimers can link FR and DS, looping out the intervening DNA. EBNA1 can also intermolecularly link DNAs to which it binds. Residues of EBNA1 that can mediate linking have been mapped to at least three, non-overlapping domains. These domains, when fused to the dimerization and DNA-binding domain of GAL4, can self-associate and thereby link DNAs bound site specifically by GAL4. Two disparate mechanisms could underlie self-association of linking domains: 1) linking domains could associate with other linking domains directly, or 2) linking domains could associate indirectly by binding to a common nucleic acid intermediate. We have found that EBNA1 can link DNA by each of these mechanisms, however, the linking domains associate directly with a greater apparent affinity than through a nonspecific nucleic acid intermediate.

Multiple regions within EBNA1 can link DNAs

Epstein-Barr virus nuclear antigen 1 (EBNA1) can bind specifically to two clusters of sites within the Epstein-Barr virus plasmid origin of DNA replication (oriP). EBNA1 activates DNA replication mediated by oriP and can also activate transcription and retain DNA in cells when bound site specifically. EBNA1 bound to oriP physically links the two clusters of EBNA1-binding sites, resulting in loop formation by the intervening DNA. To elucidate the contribution of DNA linking by EBNA1 to its biological activities, we identified regions within it that can independently link DNAs to which they are bound. An electrophoretic mobility shift assay was used to detect this activity. Proteins which link DNA aggregate that DNA into large lattices. Proteins which cannot link DNA but still bind to DNA retard the mobility of that DNA but do not cause it to form lattices. Amino-terminal truncations were used to map the amino-terminal limit of a minimal DNA-linking domain approximately to amino acid 372 of EBNA1. To map the carboxy-terminal limit of this minimal domain, fusion proteins containing the DNA-binding domain of GAL4 and fragments of EBNA1 were generated and studied. This approach identified the carboxy-terminal limit of this minimal domain to be approximately amino acid 391 and verified its amino-terminal limit. Internal deletions within a truncated EBNA1 derivative verified the importance of this region. Two additional fragments of EBNA1, each of which independently conferred DNA-linking activity on the domain of GAL4 which binds DNA, were identified within amino acids 54 to 89 and amino acids 331 to 361. Therefore, EBNA1 contains at least three regions that can act independently to link DNAs and that may act in concert within intact EBNA1.

Phylogenetic analysis of the mitochondrial genomes from Leber hereditary optic neuropathy pedigrees

The nucleotide sequences of the mitochondrial genomes from patients with Leber hereditary optic neuropathy (LHON) were used for phylogenetic analysis to study the origin and population history of pathogenic mitochondrial mutations. Sequences of both the coding region (8300 bp) and the more rapidly evolving noncoding control region (1300 bp) were analyzed. Patients with the primary LHON mutations at nucleotides 3460, 11,778, and 14,484 were included in this study, as were LHON patients and non-LHON controls that lacked these primary mutations; some of the subjects also carried secondary LHON mutations. The phylogenetic analyses demonstrate that primary LHON mutations arose and were fixed multiple times within the population, even for the small set of LHON patients that was analyzed in these initial studies. In contrast, the secondary LHON mutations at nucleotides 4216, 4917, and 13,708 arose once: the mitochondrial genomes that carried these secondary mutations formed a well-supported phylogenetic cluster that apparently arose 60,000 to 100,000 years ago. Previous studies found secondary LHON mutations at a higher frequency among LHON patients than among control subjects. However, this finding does not prove a pathogenetic role of these mutations in LHON. Instead, the increased frequency is more likely to reflect the population genetic history of secondary mutations relative to that of primary LHON mutations.

Exposure of emergency department personnel to tuberculosis: PPD testing during an epidemic in the community

STUDY OBJECTIVE

The present epidemic of tuberculosis has increased the risk of transmission of tuberculosis to health care workers in general and emergency department staff in particular, who often treat patients with tuberculosis before their diagnosis. The purpose of this study was to determine the risk of tuberculosis exposure among the nursing and physician staff of an urban ED.

DESIGN

Observational study of self-reported purified protein derivative (PPD) skin test results and tuberculosis exposure.

SETTING

Urban, public ED.

PARTICIPANTS

Attending physicians, resident physicians, and registered nurses.

INTERVENTIONS

None.

RESULTS

Questionnaires were sent to all attending physicians, resident physicians, and registered nurses in the ED at Harbor-UCLA Medical Center requesting information on the subject's present and prior PPD status, known exposure to tuberculosis, and duration of time and average number of hours worked in the ED. Ninety-six of 129 questionnaires (74%) were returned. Five of the respondents had been immunized with Bacillus of Calmette and Guerin vaccine (BCG) and 10 of the respondents were PPD positive before beginning work in the ED. Of the other 81 respondents, 31% (25 of 81) had become PPD positive while working in the ED. The majority of these conversions (15 of 25) occurred in the first 6 months of 1993. A Kaplan-Meier survival analysis revealed nearly a 40% risk of PPD conversion after 60 months of full-time work in the ED.

CONCLUSION

As measured by self-reported PPD status, a high rate of exposure to tuberculosis has been observed among the ED staff at Harbor-UCLA Medical Center. The highest rate of PPD conversion has been noted most recently, suggesting that there has been a significant increase in staff exposure to tuberculosis during 1992 and the beginning of 1993. Systematic monitoring of PPD conversion rates among ED staff is necessary to determine the adequacy of ED respiratory isolation procedures during the current tuberculosis epidemic.

Management of acute respiratory failure due to pulmonary edema with nasal positive pressure support

The management of patients with respiratory failure from cardiogenic pulmonary edema may require intubation and mechanical ventilation. This provides both ventilatory assistance as well as the beneficial hemodynamic effects of positive intrathoracic pressure. As the need for ventilation is usually short term, noninvasive ventilatory support may be adequate. We report the use of biphasic positive airway pressure by nasal mask (BiPAP system) to successfully manage two patients with respiratory failure due to pulmonary edema.

Finger prick blood testing in Leber hereditary optic neuropathy

Individuals from 33 unrelated Australian families with optic atrophy were screened for 10 different single base alterations in mitochondrial DNA (mtDNA) associated with Leber hereditary optic neuropathy (LHON) using direct polymerase chain reaction amplification of blood spots collected on Guthrie cards. This method using blood spots allows easily accessible screening for LHON mtDNA mutations with minimal biohazard risk and reduced expense in the storage and transport of specimens.

A variant of Leber hereditary optic neuropathy characterized by recovery of vision and by an unusual mitochondrial genetic etiology

The Tas2 and Vic2 Australian families are affected with a variant of Leber hereditary optic neuropathy (LHON). The risk of developing the optic neuropathy shows strict maternal inheritance, and the ophthalmological changes in affected family members are characteristic of LHON. However, in contrast to the common form of the disease, members of these two families show a high frequency of vision recovery. To ascertain the mitochondrial genetic etiology of the LHON in these families, both (a) the the nucleotide sequences of the seven mitochondrial genes encoding subunits of respiratory-chain complex I and (b) the mitochondrial cytochrome b gene were determined for representatives of both families. Neither family carries any of the previously identified primary mitochondrial LHON mutations: ND4/11778, ND1/3460, or ND1/4160. Instead, both LHON families carry multiple nucleotide changes in the mitochondrial complex I genes, which produce conservative amino acid changes. From the available sequence data, it is inferred that the Vic2 and Tas2 LHON families are phylogenetically related to each other and to a cluster of LHON families in which mutations in the mitochondrial cytochrome b gene have been hypothesized to play a primary etiological role. However, sequencing analysis establishes that the Vic2 and Tas2 LHON families do not carry these cytochrome b mutations. There are two hypotheses to account for the unusual mitochondrial genetic etiology of the LHON in the Tas2 and Vic2 LHON families. One possibility is that there is a primary LHON mutation within the mitochondrial genome but that it is at a site that was not included in the sequencing analyses. Alternatively, the disease in these families may result from the cumulative effects of multiple secondary LHON mutations that have less severe phenotypic consequences.

Leber hereditary optic neuropathy: identification of the same mitochondrial ND1 mutation in six pedigrees

Biochemical and molecular genetic evidence is presented that in six independent pedigrees the development of Leber hereditary optic neuropathy (LHON) is due to the same primary mutation in the mitochondrial ND1 gene. A LHON family from the Newcastle area of Great Britain was analyzed in depth to determine the mitochondrial genetic etiology of their disease. Biochemical assays of mitochondrial electron transport in organelles isolated from the platelet/white-blood-cell fraction have established that the members of this family have a substantial and specific lowering of flux through complex I (NADH-ubiquinone oxidoreductase). To determine the site of the primary mitochondrial gene mutation in this pedigree, all seven mitochondrial complex I genes were sequenced, in their entirety, from two family members. The primary mutation was identified as a homoplasmic transition at nucleotide 3460, which results in the substitution of threonine for alanine at position 52 of the ND1 protein. This residue occurs within a very highly conserved hydrophilic loop, is invariantly alanine or glycine in all ND1 proteins, and is adjacent to an invariant aspartic acid residue. This is only the second instance in which both a biochemical abnormality and a mitochondrial gene mutation have been identified in an LHON pedigree. The sequence analysis of the ND81 gene was extended to a further 11, unrelated LHON pedigrees that had been screened previously and found not to carry the mitochondrial ND4/R340H mutation. The ND1/A52T mutation at nucleotide 3460 was found in five of these 11 pedigrees. In contrast, this sequence change was not found in any of the 47 non-LHON controls. The possible role of secondary complex I mutations in the etiology of LHON is also addressed in these studies.

A pilot study of the effects of mechanical shortening of ewes' incisors (bite correction) on body weight and the development of periodontal disease

A field trial was set up to determine the effects of mechanical shortening of long incisors (bite correction) of ewes with early periodontal disease on the progress of the disease and on their body weights. On a farm near Te Anau with a high prevalence of periodontal disease in sheep, the body weights of 75 sound mouth ewes and two groups each of 75 ewes with periodontal disease were recorded. At the start of the trial, the incisors of the ewes in one of the groups with periodontal disease were shortened using a grinder. The trial ran for 2 years. The mouths of almost all the sheep which had sound mouths at the start of the trial remained sound throughout. This suggests that on periodontal disease-prone farms it may be possible to select ewes at 3 or 4 years of age which will retain sound mouths throughout much of thei-r productive lives. Throughout the trial, sheep with advanced periodontal disease tended to be lighter than sheep with mild periodontal disease and those in turn tended to be lighter than sheep with sound mouths. Mechanical shortening of the incisors did not alter the proportion which subsequently developed advanced periodontal disease. Seventeen to eighteen percent of ewes in both periodontal disease groups had developed advanced periodontal disease by the end of the trial. There was no significant difference in body weight between the group with shortened incisors and the group with untreated periodontal disease. Consequently, the trial provides no evidence that the mechanical shortening of the incisors of ewes will improve their productivity.

A 39-year-old man with acute hemolytic crisis secondary to intravenous injection of hydrogen peroxide

The diagnosis of cancer or its recurrence is often emotionally devastating for patients and those close to them. People may have a great deal of difficulty accepting the diagnosis and may seek others' opinions about the best course of treatment. When a physician projects that there is no hope, or if a cure is no longer probable, the patient and those close to him or her may feel helpless and hopeless. Given the resultant psychologic turmoil, the patient may be led to try unproven methods. Such methods, often referred to as "cancer quackery," represent a person's attempt to reassert personal control in response to these feelings of helplessness and hopelessness. Cancer quackery involves about $2 billion each year in the United States alone. One study demonstrated that approximately 39% of the pediatric outpatients studied had either tried, considered, or received recommendations for unproven methods of cancer treatment. Laetrile and faith healing were the most frequent methods used. One of the most recent of the unproven methods of cancer treatment that have been shown to cause life-threatening complications is IV injection of hydrogen peroxide. The scientific rationale behind this procedure is still unclear, but the side effects are clearly life threatening.

X-linked megalocornea: close linkage to DXS87 and DXS94

In a family in which X-linked megalocornea is segregating, the disease locus was found to be closely linked to DXS87 (zeta max = 3.91, theta max = 0.00) and DXS94 (zeta max = 3.34, theta max = 0.00) in Xq21.3-q22.

Skin clues in the diagnosis of life-threatening infections

Skin lesions, an important clue to the cause of septicemia, result from five main processes: (1) disseminated intravascular coagulation and coagulopathy; (2) direct vascular invasion and occlusion by bacteria or fungi; (3) immune vasculitis and immune complex formation; (4) emboli from endocarditis; and (5) vascular effects of toxins. Disseminated intravascular coagulation probably plays only a minor role in pathogenesis. Vascular invasion by bacteria may result in a severe inflammatory reaction, as in meningococcemia, or in a minimal reaction, as in ecthyma gangrenosum. Gram-stained smears of scrapings from the base of skin lesions--a frequently neglected procedure--is an important diagnostic adjunct. Skin biopsies are particularly important in the diagnosis of Rocky Mountain spotted fever and infections caused by Candida.

Antibiotic loaded plaster of Paris pellets: an in vitro study of a possible method of local antibiotic therapy in bone infection

Plaster of Paris is an effective ancillary treatment in the surgery of infected cavities in bone. It is well tolerated and spontaneously absorbed over a period of weeks to months, being replaced by bone of normal architecture. It effectively obliterates much of the dead space, leaving little room for hematoma formation. It would appear logical to treat local infection, especially involving rigid walled cavities, by a locally diffused antibiotic. When incorporated into plaster of Paris pellets, two antibiotics, Fucidin and gentamicin, are capable of prolonged local release in bacteriocidal concentrations. On the basis of in vitro observations on bacterial cultures, it is proposed that antibiotic-plaster of Paris pellets might be a simple adjuvant technique to good surgical debridement in the treatment of bone infection. Plaster of Paris has the practical advantage over acrylic cement beads containing antibiotics in that it is resorbed and would not need a subsequent operation to be moved.