Sources of Mutagenic Activity in Urban Fine Particles

Samples were collected during the winter of 1984—1985 in the cities of Albuquerque, NM and Raleigh NC as part of a US Environmental Protection Agency study to evaluate methods to determine the emission sources contributing to the mutagenic properties of extractable organic matter (EOM) present in fine particles. Data derived from the analysis of the composition of these fine particles served as input to a multi-linear regression (MLR) model used to calculate the relative contribution of wood burning and motor vehicle sources to mutagenic activity observed in the extractable organic matter. At both sites the mutagenic potency of EOM was found to be greater (3—5 times) for mobile sources when compared to wood smoke extractable organics. Carbon-14 measurements which give a direct determination of the amount of EOM that originated from wood burning were in close agreement with the source apportionment results derived from the MLR model.

Patterns in Pediatric Dental Surgery under General Anesthesia across 7 State Medicaid Programs

OBJECTIVES

Children's access to dental general anesthesia (DGA) is limited, with highly variable wait times. Access factors occur at the levels of facility, dental provider, and anesthesia provider. It is unknown if these factors also influence utilization of dental surgery. We characterized patterns in DGA utilization by system, provider, population, and individual disease levels to explain variation.

METHODS

We conducted a cross-sectional analysis of Medicaid-enrolled children (≤9 y) who received DGA in Massachusetts, Maryland, Texas, Connecticut, Washington, Illinois, and Florida from 2011 to 2012. DGA events were characterized by the place of service, measures of disease burden, average reimbursements for dental provider and anesthesia provider, and average total expenditures.

RESULTS

A total of 10,149,793 children met study eligibility criteria. States with similar patterns of caries-related visits, such as Illinois (16% of Medicaid enrollees had a caries-related claim) and Washington (22%), had different DGA rates (1% and 17%, respectively). Reimbursement rates for dental providers, DGA services, and nonhospital places of services did not consistently align in states with higher DGA rates. Surgical extraction rates, as a proxy for the most severe disease, exceeded 75% in Maryland, which had the lowest DGA rate (0.3%).

CONCLUSIONS

Variation in DGA rates across states was not explained by reimbursements rates (provider, DGA services, place of service) or population or individual level of caries burden. Efforts to evaluate and alter utilization of DGA should consider factors such as dental and anesthesia provider capacity, health facility capacity (hospital vs. ambulatory surgery center vs. office), and population- and individual-level disease burden. Our negative findings suggest the presence of other social determinants of oral health that influence utilization of services (e.g., race/ethnicity, language preference, immigration status, policy and budget goals), which should be explored. Our findings also raise the specter that variation in surgical rates may represent instances of unmet needs or overtreatment.

KNOWLEDGE TRANSFER STATEMENT

The results of this study can be used by clinicians and policy makers as they address policy and clinical interventions to influence children with severe caries. Interventions to change utilization of surgical services on a population level may need to include state-specific factors that extend beyond reimbursement, disease burden, anesthesia provider type, or facility type.

Disparities in Emergency Department Pain Treatment for Toothache

Racial disparities in how pain is treated in the emergency department (ED) for toothache have not been reported. Due to increasing reliance on EDs for dental care, the authors investigated whether race/ethnicity and insurance type are associated with treatment for toothache pain. The authors conducted a nationally representative cross-sectional study of ED toothache visits by adults (19 to 64 y old), using the 2008-2010 National Hospital Ambulatory Medical Care Survey. Multinomial regression models accounted for the complex survey design. Outcomes were pain medicines received: none, nonopioid only, or opioids. After adjusting for sociodemographic factors, black patients had 1.99 greater odds (P < 0.005) than white patients of receiving only a nonopioid pain medicine for toothache. Visits made by patients on Medicare, Medicaid, uninsured, or "other" insurance status had greater odds than the privately insured of receiving only a nonopioid pain medicine rather than an opioid (odds ratios, respectively: 4.8, P < 0.001; 2.1, P ≤ 0.001; 2.3, P < 0.01; and 4.1, P < 0.001). Blacks are less likely than whites to receive opioids in the ED for a toothache, even with similar levels of pain. Nonprivately insured patients have lower odds than the privately insured to receive opioids for toothache pain. A better understanding of the etiology of these disparities could lead to directed interventions. Knowledge Transfer Statement: This study presents findings novel to the body of pain and oral health care literature. Because there is an increasing reliance on the emergency department to address dental pain, disparities in how toothache pain is treated will be of great interest to a growing number of Americans, clinicians, and policy makers.

Small-scale Arctic charr Salvelinus alpinus fisheries in Canada's Nunavut: management challenges and options

The Arctic charr Salvelinus alpinus is a diverse and abundant resource in Canada's Nunavut. The anadromous form is primarily targeted by exploitation in small-scale fisheries. The continued importance of subsistence fisheries and growing interest in further developing commercial fisheries underline the need for proper management of S. alpinus in northern Canada. This paper presents the current state of S. alpinus fisheries in Nunavut and related management challenges. An alternate framework for assessment using life-history information as it determines stock productivity and resilience to harvesting is presented. This framework combines (1) a risk assessment tool [productivity-susceptibility analysis (PSA)] to evaluate the relative vulnerability of S. alpinus stocks to harvest and (2) a conceptual model for quantitative assessment to determine sustainable harvest levels. Diversity in S. alpinus life history and contrast in vulnerability scores derived from PSA assessment are demonstrated for a sample of 86 anadromous stocks from throughout Nunavut. These data provide evidence in support of an alternate strategy for assessment permitting to integrate diversity in S. alpinus life history for improved generalization and representativeness. Salvelinus alpinus fisheries in Arctic regions exemplify the need for stock assessment and management alternatives to ensure fish conservation in remote, sensitive ecosystems and in data-poor circumstances.

N-VINYLPYRROLIDONE AS A WATER COMPATIBLE CONSTITUENT OF EMBEDDING RESINS FOR SECTIONING IN ELECTRON MICROSCOPY

The use as an embedding resin for ultrathin sectioning of a cross-linked triple copolymer of N-vinylpyrrolidone, acrylonitrile, and ethylene glycol dimethacrylate is described. The first of these components is miscible with water, in all proportions, and can be used as a dehydrating agent, or, alternatively, ethanol may be used in the standard way. Polymerization is carried out at 37°C or even lower temperatures. This resin is unsuitable for use after osmium fixatives, but after permanganates it gives results similar to epoxy. Photographs of rye root-tip cells fixed in permanganate and sectioned in this resin are presented. Because of the water-permeable nature of the product and low polymerization temperature, this resin appears to have possibilities for histochemistry.

Assessment of subchondral bone mineral density in equine metacarpophalangeal and stifle joints

Functional relationships between articular cartilage and underlying subchondral bone have been shown to be associated with the progression of osteoarthritis (OA). However, quantifiable factors substantiating this relationship do not exist. Therefore, the study objective involved quantifying subchondral bone mineral density (BMD) of the equine metacarpophalangeal (MCP) and stifle joints as a step in determining if regional subchondral BMD may be associated with OA changes. BMD was bilaterally quantified using dual energy xray absorptiometry (DEXA) for four subchondral regions: palmer and dorsal aspect of the medial 3rd metacarpal (MC3P, MC3D), medial femoral condyle (MFC), and the medial trochlear ridge (MTR). BMD (g/cm2) was measured using a 5.2 x 5.2 mm region of interest in the subchondral bone area. To account for the differences in thickness, BMD (g/cm2) was divided by sample thickness providing volumetric BMD (g/cm3). No significant effect of side on BMD values was found (p > 0.72). However, there were significant differences in BMD found between all regions (p < 0.05). The volumetric BMD of the MC3P region was significantly greater than the MC3D and the MC3D was greater than the MFC, while the MFC was greater than the MTR (MC3P > MC3D > MFC > MTR). The MCP regions had a higher volumetric BMD than the stifle regions possibly due to higher weight distribution, smaller articular surface area, and joint geometry. The adaptive bone structural variations between the regions studied were shown to be significant. Mechanical properties of the overlying cartilage are currently being analyzed to correlate with these results and provide a possible diagnostic method to investigate OA progression.

Use of the Dermatology Life Quality Index (DLQI) in a midwestern US urban clinic

BACKGROUND

The Dermatology Life Quality Index (DLQI), a self-administered general dermatology quality of life instrument, was originally developed and published in a dermatology clinic at University Hospital of Wales.

OBJECTIVE

Our goal was to test the feasibility of having patients answer the DLQI in a busy dermatology clinic and to find out to what extent results vary from those published in Wales. We also wanted to examine the validity of the index in terms of the correlation between DLQI scores and stage of illness (disease severity).

METHODS

We administered the DLQI to 200 consecutive patients who were seen in a dermatology clinic at Indiana University Medical Center. Results were examined in light of results found by those who originated the DLQI. A pilot group of patients were given the DLQI and rated for severity of disease by means of the Dermatology Index of Disease Severity (DIDS).

RESULTS

Overall, the DLQI is easy to administer and can be completed within 3 minutes. The scores in our study were compatible with those previously reported by the DLQI originators. There was a "ceiling" effect in that 11% of the patients indicated no quality of life impairment on the DLQI rating. This index shows stratification with severity of disease.

CONCLUSION

The DLQI is an easy and efficient instrument for assessing quality of life in dermatology patients. Patients needed minimal assistance with the form. Our results were similar to those of the DLQI originators, and this further shows reliability and validity of the DLQI. In addition, this study further supports the use of DLQI as a quality of life instrument suitable for use in international studies.

Comparison of tunnel suture and suture anchor methods as a function of time in a sheep model

There is little quantitative information available on the required healing time after a rotator cuff surgery. This study evaluated two surgical procedures by comparing the healing strength as a function of time of the tendon in a bone trough using a sheep model. The two surgical procedures compared were bioabsorbable suture anchors and bone tunnel suture technique. The infraspinatus tendon was split in half and procedure (suture anchor/tunnel suture) locations were randomly allocated to the proximal or distal half of the tendon at the healing time points of 0, 3, 6, 9, and 12 weeks with n = 6 at t = 0 and n = 8 in all other groups. At each time point, the surgical (right) and normal (left) shoulders were harvested and stored in a -30 degrees C freezer until testing. Biomechanical testing was performed using a MTS 809 Axial/Torsional Servohydraulic System. Special cryo-grips designed and built to test the infraspinatus tendon-bone interface in anatomical alignment were used. All samples were preloaded with 5 Newtons, and then force was measured during a crosshead displacement of 50 cm/min until failure. Force and displacement data were recorded to calculate load to failure and stiffness of the bone-tendon construct. There was only significant difference (95% CI) in mean tensile force at week 0, with the bone tunnel suture technique tensile force greater than the suture anchor method tensile force (p = 0.0261). There was no significant difference between stiffness means at any of the survival times.

The effect of immobilization on rotator cuff healing using modified Mason-Allen stitches: a biomechanical study in sheep

Long-term biomechanical integrity of the surgical site is crucial to the outcome of rotator cuff repair. Usually after rotator-cuff surgery, the arm is immobilized for 6-12 weeks to minimize disruption at the healing site. Unfortunately, currently there is very little clinical data on the effects of immobilization after rotator cuff surgery. This study analyzed the effect of immobilization on rotator cuff healing by comparing the healing strength of the tendon in a bone trough using a sheep model. In sixteen (16) female adult sheep, the right infraspinatus tendons were reattached into a bone trough using a modified Mason-Allen suture pattern. After surgery, each sheep was randomly assigned into either an immobilized or non-immobilized treatment group. The immobilized group was fitted with a softball taped under the foot to restrict limb movement for 6 weeks. The non-immobilized treatment group was allowed to fully bear weight on the treated shoulder. At 26 weeks, the animals were sacrificed and the surgical shoulders were harvested and stored in a -30 degrees C freezer. Biomechanical testing was performed using a MTS 809 Axial/Torsional Servohydraulic System. Special cryo-grips were used to test the infraspinatus tendon-bone interface in anatomical alignment. All samples were preloaded with 10 +/- 5 N, and then force was measured during a crosshead displacement of 500 mm/min until failure. Force and displacement were acquired at 100 Hz and used to calculate load-to-failure and stiffness of the bone-tendon interface. The load-to-failure (N) and stiffness (N/cm) were determined for both treatment groups. For the non-immobilized group, the loads to failure and stiffness means were 2571.95 +/- 329.9 N and 2319.09 +/- 457.72 N/cm. The immobilized group means were 2954.42 +/- 473.52 N (load-to-failure) and 2579.13 +/- 383.51 N/cm (stiffness). A two-tailed two-samples unequal variance student t-test with significance set at 0.05, found no significant difference between the treatment groups for load-to-failure (p = 0.2174) and stiffness (p = 0.8286).

The role of the pediatrician in the oral health of children: A national survey

OBJECTIVES

To assess pediatricians' knowledge, attitudes, and professional experience regarding oral health, and to determine willingness to incorporate fluoride varnish into their practices.

BACKGROUND

Poor and minority children suffer disproportionately from dental caries and have limited access to dental care. In a recent analysis of national survey data, the General Accounting Office reported that poor children had 5 times more untreated decay than did children from higher income families. Untreated decay can lead to problems with eating, speaking, and attending to learning. Children who are poor suffer 12 times the number of restricted activity days because of dental problems, compared with more affluent children. Despite higher rates of dental decay, poor children had one half the number of dental visits compared with higher income children in 1996. Medicaid's Early Periodic Screening Diagnosis and Treatment (EPSDT) program is intended to provide regular dental screenings and appropriate treatment but has apparently played a limited role in improving access to dental care for poor children. According to a report by the Office of the Inspector General of the Department of Health and Human Services, only 20% of children under 21 years of age, who were enrolled in Medicaid and eligible for EPSDT, actually received preventive dental services. By increasing their involvement in oral health prevention during well-child care visits, pediatricians may be able to play an important role in improving the dental health of their patients who have difficulty obtaining access to professional dental care. However, it is unclear to what degree pediatricians are knowledgeable about preventive oral health and the extent to which they may already be participating in prevention and assessment. Also, little is known about the incidence of dental problems in pediatric practice, and whether pediatricians perceive barriers to their patients' receiving professional dental care. Finally, it is important to know how pediatricians value the promotion of oral health and whether they would be willing to take on additional activities aimed at its improvement. We addressed these questions in a national survey of pediatricians.

DESIGN

We surveyed a national sample of 1600 pediatricians randomly selected from the American Medical Association Master File to assess their knowledge, current practice, and opinion on their role in the promotion of oral health; experience with dental decay among patients and in referring patients for professional dental care; and willingness to apply fluoride varnish.

RESULTS

Of 1386 eligible survey recipients, 862 returned surveys for a response rate of 62%. Respondents reported seeing dental problems regularly. Two thirds of respondents observed caries in their school-aged patients at least once a month. Of the respondents, 55% reported difficulty achieving successful dental referrals for their uninsured patients and 38% reported difficulty referring their Medicaid patients. More than 90% of the respondents agreed that they had an important role in identifying dental problems and counseling families on the prevention of caries. Moreover, respondents were interested in increasing their involvement: 74% expressed a willingness to apply fluoride varnish in their practices. One half of the respondents, however, reported no previous training in dental health issues during medical school or residency, and only 9% correctly answered all 4 knowledge questions.

CONCLUSION

Access to dental care and unmet dental health needs are serious, under addressed problems for poor and minority children in the United States. In promoting preventive oral health, pediatricians benefit all children and particularly the underserved. We know of 2 states, Washington and North Carolina, that have acknowledged, through the provision of reimbursement, that pediatricians have a unique opportunity at well-child care visits to provide caries prevention c

Increased cytotoxicity of food-borne mycotoxins toward human cell lines in vitro via enhanced cytochrome p450 expression using the MTT bioassay

Eight food-borne mycotoxins epidemiologically implicated in human disease were tested for their cytotoxic effects on human cells previously immortalised and transfected to introduce human cytochrome p450 (CYP 450) genes. Such cells retain many characteristics of normal cell growth and differentiation while simultaneously having the potential of either increasing or decreasing the metabolic activity (cytotoxicity) of the challenging mycotoxins. The MTT assay provided an indication of cytotoxicity. Of the nine CYP450s introduced CYP1A2 was most effective, rendering the cells 540 times more sensitive than the control cells to aflatoxin B1, 28 times more sensitive to aflatoxin G1 and 8-fold more sensitive to ochratoxin A. CYP3A4 resulted in the cells being 211 times more toxic to aflatoxin B1 and 8-fold more toxic to aflatoxin G1 while CYP 2A6, CYP 3A5 and CYP 2E1 also produced observable effects. No increase in metabolic activity was found using cyclopiazonic acid, deoxynivalenol, fumonisin B1, patulin or T-2 toxin. CD5Os were calculated for the mycotoxins against the non-CYP-introduced control cells. There was almost a five order of magnitude difference between the most toxic, T-2 toxin (CD50 0.0057 microgram/ml) and the least toxic, fumonisin B1 (CD50 476.2 micrograms/ml). In vitro biological assays thus provide an excellent system for quantifying the often low CD50s expressed by mycotoxins in foods.

Intracardiac transplantation of skeletal myoblasts yields two populations of striated cells in situ

BACKGROUND

Adult heart lacks stem cells and cannot effectively regenerate. In contrast, skeletal muscle is constantly undergoing repair. We proposed to transplant immature skeletal myoblasts into injured myocardium.

METHODS

Approximately 7x10(6) soleus skeletal myoblasts were expanded in vitro from adult New Zealand White rabbits (n = 23) whose posterior left ventricle was cryoinjured to create a transmural lesion. Autologous myoblasts (n = 18) or saline (n = 5) was transplanted into the central cryolesion at the time of injury (n = 6) or 1 week later (n = 12). Hearts were harvested 2 weeks after injection.

RESULTS

Myoblast transfer did not incur further morbidity. After cryolesion, grossly, a 1.6-cm epicardial hemorrhagic lesion could be seen. Histologically, the transmural lesion contained inflammatory cells and active scarring but no viable cardiomyocytes. Electron microscopy demonstrated a predominance of collagen and fibroblasts. Nine hearts contained multinucleated cells within the cryolesion that covered approximately 75% of the central cryolesion in 17% of animals. Immunohistochemical analysis confirmed their skeletal muscle origin. At the periphery of the lesion, isolated clusters of nonskeletal muscle cells could be visualized (n = 12) that resembled immature cardiocytes.

CONCLUSIONS

Autologous skeletal myoblasts can regenerate viable striated tissue within damaged myocardium. Myoblast transfer warrants further investigation as a new method for improving myocardial performance within infarcted myocardium.

A load-independent in vivo model for evaluating therapeutic interventions in injured myocardium

Although cardiomyocyte damage is normally irreversible, gene therapy and somatic cell transfer offer potential for improving function in damaged regions of the heart. However, in ischemic models of injury, variability in depth, size, and location of damage compromises statistical evaluation of in vivo function. We have adapted cryoablation to create a reproducible, posterior, transmural lesion within rabbit myocardium in which small changes in function are measurable in vivo. Before and at 2 and 6 wk postinjury, in vivo left ventricular intracavitary pressure and myocardial segment length were measured. Regional indexes of performance, segmental stroke work (SW), and percent systolic shortening (SS) were significantly decreased (P < 0.001) postcryoinjury as was the slope (Mw) of the linear preload recruitable SW relationship between SW and end-diastolic segment length (P = 0.0001). Decreased SW, SS, and Mw correlated with wall thinning, loss of myocytes, presence of fibroblasts, and transmural scar formation. Reproducible changes in regional myocardial performance in vivo postcryoinjury suggest that this is a reasonable model for evaluating novel therapies for cardiovascular disease.

An exploratory look at hydrocarbon data from the Photochemical Assessment Monitoring Stations network

This paper describes some characteristics of speciated nonmethane organic compound (NMOC) data collected in 1994 at five Photochemical Assessment Monitoring Stations (PAMS) and archived in the U.S. Environmental Protection Agency's Aerometric Information Retrieval System (AIRS). Topics include data completeness, distribution of individual NMOCs in concentration categories relative to minimum detectable levels, percentage of total NMOC associated with the sum of the 55 PAMS target compounds, and use of scatterplots to diagnose chromatographic misidentification of compounds. This is an early examination of a database that is expanding rapidly, and the insights presented here may be useful to both the producers and future users of the data for establishing consistency and quality control.

Reliability testing of the dermatology index of disease severity (DIDS). An index for staging the severity of cutaneous inflammatory disease

OBJECTIVES

To describe a new severity of illness index for inflammatory skin disease called the Dermatology Index of Disease Severity (DIDS), and to show its preliminary use and reliability in staging disease in patients with psoriasis and dermatitis.

DESIGN

Interobserver rating study using the DIDS with as many as 10 observers independently rating the same patient at a single point in time.

SETTING

Ambulatory care clinics at an academic medical center with patients from various socioeconomic backgrounds.

PATIENTS

Thirty-four patients with psoriasis and 15 patients with dermatitis were included in the study.

MAIN OUTCOME MEASURES

The severity of illness for each patient was rated as 1 of 5 stages: 0, no evidence of clinical disease; I, limited disease; II, mild disease; III, moderate disease; and IV, severe disease. The degree of interobserver concordance was measured by the Cohen kappa statistic.

RESULTS

All 5 stages were represented in the study of patients with psoriasis. The overall kappa statistic was 0.76, which is defined as substantial interobserver concordance. The use of the instrument in dermatitis showed good consensus in staging, where the kappa statistic was 0.41.

CONCLUSION

We introduce an easy and efficient instrument for staging the severity of illness in inflammatory cutaneous diseases. The reliability of the DIDS is demonstrated in patients with psoriasis and in patients with dermatitis.

Outcomes research: an overview

During the past few years there has been significant interest in studying methods that document outcomes of medical care. Outcomes management should result in higher quality health care at lower cost. However, what does outcomes research mean and how does it apply to dermatology and specifically to the individual dermatologist? This article reviews the evolution of medical outcomes research and presents the status of the current instruments, indices, and methods.

A pityriasis rosea-like eruption secondary to bacillus Calmette-Guérin therapy for bladder cancer

The use of bacillus Calmette-Guérin (BCG) for the treatment of bladder cancer has been followed by reports documenting adverse reactions. Eruptions of the skin have been included (although not well described) in the list of side effects. We report a pityriasis rosea-like rash secondary to BCG therapy for bladder cancer. Although the treatment was interrupted because of this reaction, the medication was restarted later with only a mild transient recurrence of the eruption.

Assessment of the Frank-Starling relationship by two-dimensional echocardiography

The Frank-Starling relationship between left ventricular stroke work and end-diastolic minor-axis cross-sectional area was evaluated as a load-insensitive measure of inotropic state by two-dimensional echocardiography in 10 conscious dogs. Stroke work was calculated as the product of systolic change in cross-sectional area and either (1) beat-to-beat mean arterial pressure or (2) initial systolic blood pressure. Both Frank-Starling relationships were highly linear during preload variation (mean r = 0.96), sensitive to the inotropic state (slope increase with calcium 51% +/- 43% and 62% +/- 53%, respectively), and insensitive to afterload (r < 0.4, slope or x intercept versus afterload). Thus the Frank-Starling relationships derived from two-dimensional echocardiographic images and peripheral arterial pressure may be a useful and practical means of assessing inotropic state with minimally invasive measurements.

Management of pseudofolliculitis barbae

Pseudofolliculitis barbae is a common dermatologic conditions primarily affecting black men who shave closely on a regular basis. Figures cited in the literature indicate 10 to 83% of black men have some form of it. Commonly encountered in the military, pseudofolliculitis barbae has caused significant problems in all commands, both medically and administratively. This article will review the pathogenesis of pseudofolliculitis barbae and provide a variety of treatment modalities. Proper treatment is essential to avoid unnecessary scarring, pigmentation, and keloid formation.

Drug-nutrient interactions in three long-term-care facilities

OBJECTIVE

To assess the risk of drug-nutrient interactions (DNIs) in three long-term-care facilities.

DESIGN

Retrospective audit of charts.

SETTING

Three long-term-care facilities in central New York State.

SUBJECTS

Fifty-three patients selected randomly from each facility.

MEASUREMENT

Data were collected from the medical record of each patient for a period of 6 months. A computerized algorithm was used to assess the risk for DNIs. Mean drug use, most frequently consumed drugs, incidence of potential DNIs, and the most commonly observed potential DNIs are reported.

RESULTS

In facilities A, B, and C, respectively, patients consumed a mean of 4.86, 4.04, and 5.27 drugs per patient per month and were at risk for a mean of 1.43, 2.69, and 1.43 potential DNIs per patient per month. The most commonly observed potential DNIs were gastrointestinal interactions affecting drug bioavailability and interactions affecting electrolyte status.

CONCLUSIONS

Patients in long-term-care facilities, who are primarily elderly and chronically ill and who consume multiple medications, are at notable risk for certain DNIs. Efforts need to be made to ensure appropriate pharmacologic and nutrition therapies as well as adequate and timely monitoring of patients in these facilities. Dietitians can play an important role in training other health professionals and in designing policies to prevent DNIs.

Regional geometry and function during myocardial ischemia and recovery

To define the effects of altered left ventricular (LV) geometry on regional myocardial function during ischemia and recovery, regional and global LV geometry and transmural pressure (P) were measured in seven conscious dogs with sonomicrometry and micromanometry. Data were obtained at steady state and during rapid vena caval occlusion (VCO) under control conditions, after 15 min of left anterior descending occlusion, and after 1, 4, and 24 hr of reperfusion. Regional midwall minor axis (MA) Lagrangian strain (epsilon) and stress (sigma) were calculated from measured MA segment length (L), MA midwall radius, and wall thickness. Unstressed regional geometry was quantified using L0, the value of L at P = 0 during maximal VCO. Conventional (SWL) and normalized (SW sigma epsilon) regional MA stroke work were calculated for each cardiac cycle as the area of P vs L and sigma vs epsilon relationships, respectively. Regional Frank-Starling mechanisms corrected for changes in unstressed LV geometry were quantified as the slope (M sigma epsilon) of the linear end diastolic epsilon vs SW sigma epsilon relationship for data obtained during VCO (mean r = 0.98). M sigma epsilon returned to baseline levels within 1 h of reperfusion (P = 0.314 vs control). In contrast, 15 min of ischemia increased L0 by 15.2 +/- 2.5% (P < 0.05), which remained increased 5.7 +/- 1.7% above control values after 1 hr of reperfusion (P < 0.05). Both steady-state SWL and SW sigma epsilon decreased with ischemia and slowly returned towards baseline, remaining 28.7 +/- 7.5% and 26.4 +/- 6.3% below control values after 1 hr of reperfusion (both P < 0.05). Therefore, late functional recovery from reversible ischemic injury is primarily correlated with reversal of changes in regional geometry, specifically the reversal of diastolic creep. As a result, adequate quantification of postischemic regional myocardial performance requires characterization of changes in regional geometry as well as indicators of Frank-Starling mechanisms.

The effects of local ventricular pacing on recovery from regional myocardial ischemia

After surgical revascularization of ischemic myocardium, temporary ventricular pacing is often used, yet no data exist to indicate whether pacing ischemic versus nonischemic myocardium affects myocardial recovery. Therefore, chronically instrumented conscious dogs were studied with segment length transducers in the left anterior descending (LAD) distribution, left ventricular and pericardial micromanometers, pneumatic occluders on the LAD and venae cavae, and bipolar ventricular pacing wires, one pair in the LAD zone and one pair in the nonischemic (LCX) zone. Six dogs underwent a total of twelve 15-min LAD occlusions, each followed by 48 hr of reperfusion. Just after reperfusion, either the LAD or LCX zone was paced at 150 bpm for 45 min. LAD versus LCX pacing decreased regional stroke work (6 +/- 5 versus 19 +/- 5 kerg.cm-2) and produced contractile asynchrony. Myocardial contractile function was assessed using preload recruitable work area (PRWA), the area under the regional stroke work versus end-diastolic length relationship. Relative to LCX pacing, LAD pacing significantly delayed the recovery of PRWA after 4 hr of reperfusion (54 +/- 9 versus 83 +/- 9% control PRWA, P < 0.05). Perhaps by increased contractile asynchrony despite the decreased regional stroke work, ventricular pacing of ischemically injured myocardium delays functional recovery and should be avoided in clinical settings where the ventricular pacing site may be chosen.

Cytotoxic fungal spores in the indoor atmosphere of the damp domestic environment

Eight-three fungal isolates collected and cultured from the air spora of damp public sector Scottish housing have been screened for cytotoxic properties. A bioassay procedure has been utilised for this purpose involving cytotoxic effects on human embryonic diploid fibroblast lung cells grown as monolayer cultures within the wells of microtitre plates. The MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] biochemical assay system employed has revealed that 39 (47%) of the moulds investigated possessed spore-associated cytotoxic properties; a value which emphasises the potential health hazards of the continual inhalation of toxigenic fungal propagules by occupants of mouldy houses. Penicillia, the most prevalent fungi found in the internal atmosphere of the domestic environment, accounted for the great majority of cytotoxic strains identified.