Attraction of southern pine engravers and associated bark beetles (Coleoptera: Scolytidae) to ipsenol, ipsdienol, and lanierone in southeastern United States

We determined the response of the small southern pine engraver, Ips avulsus (Eichhoff); eastern fivespined ips, Ips grandicollis (Eichhoff); sixspined ips, Ips calligraphus (Germar); and pine engraver, Ips pini (Say) to the pheromones (+/-)-ipsenol, (+/-)-ipsdienol, and lanierone in the southeastern United States. Catches of I. avulsus and I. grandicollis to baited multiple-funnel traps were increased by (+/-)-ipsenol and (+/-)-ipsdienol in Florida, Georgia, Louisiana, and North Carolina. In all four localities, the highest numbers of I. avulsus were caught in traps baited with the combination of (+/-)-ipsenol, (+/-)-ipsdienol, and lanierone. In Florida, the highest numbers of I. grandicollis were captured in traps baited with the combination of (+/-)-ipsenol and (+/-)-ipsdienol (with or without lanierone). In the remaining three localities, the largest catches of I. grandicollis occurred in traps baited with (+/-)-ipsenol alone or the combination of (+/-)-ipsenol and (+/-)-ipsdienol (with or without lanierone). (+/-)-Ipsdienol was the only consistent attractant for I. calligraphus and I. pini. Attraction of I. pini in North Carolina to (+/-)-ipsdienol-baited traps was synergized by lanierone but interrupted with (+/-)-ipsenol. The interruptive effect of (+/-)-ipsenol on attraction of I. pini to (+/-)-ipsdienol was negated by lanierone. (+/-)-Ipsdienol was attractive to black turpentine beetle, Dendroctonus terebrans (Olivier), in Florida but not North Carolina, whereas (+/-)-ipsdienol was attractive to I. calligraphus in Louisiana, Georgia, and Florida. Both (+/-)-ipsenol and (+/-)-ipsdienol affected catches of Gnathotrichus materiarus (Fitch) in North Carolina. Trap catches of Hylurgops rugipennis pinifex (Fitch), Hylastes salebrosus Eichhoff, and Hylastes tenuis Eichhoff were unaffected by the pheromone treatments. The combination of (+/-)-ipsenol, (+/-)-ipsdienol, and lanierone may be a cost-effective general lure for I. avulsus, I. grandicollis, and I. pini.

Alternatives to antibiotics: chemical and physical antimicrobial interventions and foodborne pathogen response

Successful control of foodborne pathogens requires placement of chemical and physical hurdles in the preharvest and postharvest food production sectors. Pathogens may also encounter indigenous antimicrobials in foods including certain botanical compounds that have historically been used for flavor enhancement as well as preservation. Chemical additives have traditionally included organic acids to control microbial contamination in foods and feeds. However, there is some concern that continuous application of certain chemical antimicrobials can lead to a buildup of microbial resistance. This creates problems if foodborne pathogens survive and develop resistance to a variety of environmental stressors encountered in pre- and postharvest animal production. To expand the diversity of potential antimicrobials that have practical application to food animal production requires exploring the interaction between the food matrix and foodborne pathogens. There is potential for isolating antimicrobial compounds that exhibit mechanisms unrelated to conventional antimicrobial compounds. However, understanding the potential for novel antimicrobial compounds in foods and feeds will require the physiological examination of foodborne pathogen response under experimental conditions comparable to the environment where the pathogen is most likely to occur. Research on foodborne Salmonella pathogenesis is extensive and should provide a model for detailed examination of the factors that influence antimicrobial effectiveness. Analysis of pathogen response to antimicrobials could yield clues for optimizing hurdle technologies to more effectively exploit vulnerabilities of Salmonella and other foodborne pathogens when administering antimicrobials during food and feed production.

Phenotype screening for genetically determined age-onset disorders and increased longevity in ENU-mutagenized mice

With the goal of discovering genes that contribute to late-onset neurological and ocular disorders and also genes that extend the healthy life span in mammals, we are phenotyping mice carrying new mutations induced by the chemical N-ethyl-N-nitrosourea (ENU). The phenotyping plan includes basic behavioral, neurohistological, and vision testing in sibling cohorts of mice aged to 18 months, and then evaluation for markers of growth trajectory and stress response in these same cohorts aged up to 28 months. Statistical outliers are identified by comparison to test results of similar aged cohorts, and potential mutants are recovered for re-aging to confirm heritability of the phenotype.

Adjunctive use of atypical antipsychotics and anticholinergic drugs among patients with schizophrenia

BACKGROUND

Treatment of schizophrenia with antipsychotics is often associated with extrapyramidal symptoms (EPS), a disorder involving involuntary muscle movement. Because EPS are often associated with the use of antipsychotics, anticholinergic agents are often indicated.

OBJECTIVE

In this observational, retrospective study, we examined whether the initiation of olanzapine or risperidone, the two most widely prescribed atypical antipsychotics, is related to the adjunctive use of anticholinergic agents.

METHOD

We identified patients with schizophrenia from outpatient clinics in the Veterans Health Administration (VA) and defined initiation of olanzapine or risperidone as patients who were not on any antipsychotics for 6 months and subsequently initiated on the target drug between 1/4/1999 and 31/3/2000. The data were analysed using tests of means or chi-square tests.

RESULTS

The study yielded two major findings. First, compared with risperidone initiators, there were significantly fewer olanzapine initiators who used at least one anticholinergic agent adjunctively. Secondly, among olanzapine or risperidone initiators, patients who used at least one anticholinergic agent adjunctively tended to stay on the target drug significantly longer than those who did not use any anticholinergic agent adjunctively with the target drug.

CONCLUSION

As the use of anticholinergics is a proxy for the presence of EPS, these findings suggest that risperidone may be more associated with EPS than olanzapine. However, to assess the benefits and side effects associated with olanzapine or risperidone, future research needs to examine various patient outcomes resulting from the initiation of each drug.

The Collaborative Cross, a community resource for the genetic analysis of complex traits

The goal of the Complex Trait Consortium is to promote the development of resources that can be used to understand, treat and ultimately prevent pervasive human diseases. Existing and proposed mouse resources that are optimized to study the actions of isolated genetic loci on a fixed background are less effective for studying intact polygenic networks and interactions among genes, environments, pathogens and other factors. The Collaborative Cross will provide a common reference panel specifically designed for the integrative analysis of complex systems and will change the way we approach human health and disease.

Initiation of atypical antipsychotic agents and health outcomes in patients with schizophrenia

BACKGROUND

Although pharmacological treatments are available for patients with schizophrenia, there is a lack of systematic and comprehensive evaluation of health outcomes following the initiation of atypical antipsychotic agents.

OBJECTIVE

To assess the effects of the initiation of olanzapine or risperidone, the two most widely prescribed atypical antipsychotics, on patients' health outcomes, as measured by changes in patient clinical characteristics between 6 months prior to and post-initiation.

METHOD

We identified patients with schizophrenia by >1 inpatient or > or = 2 outpatient ICD-9-CM codes (> or = 7 days apart) between 1 July 1998 and 30 June 1999, and those who were initiated on olanzepine or risperidone during the period 1 April 1999 to 31 March 2000 inclusive. We then subdivided these patients into three groups: (i) those who were not on olanzapine or risperidone, (ii) those who were not on any atypical agents, and (iii) those who were not on any antipsychotic agents, for 6 months prior to being issued with the new prescription. Using test of means or chi-square tests, we examined whether the initiation of olanzapine or risperidone is related to different changes in patient clinical indicators, such as number of drugs for psychiatric conditions, use of psychiatric services, and use of non-psychiatric services.

RESULTS

Between pre- and post-initiation, olanzapine initiators had a greater decrease in the number of psychiatric hospitalizations and use of psychotropic agents, whereas risperidone initiators had a greater reduction in the number of non-psychiatric hospitalizations. The initiation of olanzapine and risperidone appear to be associated with different patient health outcomes. Compared with olanzapine initiators, risperidone initiators had a greater increase in the use of treatments related to mental health, but had greater decrease in the use of treatments related to physical health.

CONCLUSION

Despite olanzapine and risperidone being often perceived as similar antipsychotic agents, our results suggest that the clinical outcomes associated with their use are different. Outcome data from routine clinical practice are required to provide a more comprehensive assessment of these drugs.

Wound dressings in diabetic foot disease

Wound dressings represent a part of the management of diabetic foot ulceration. Ideally, dressings should alleviate symptoms, provide wound protection, and encourage healing. No single dressing fulfills all the requirements of a diabetic patient with an infected foot ulcer. Dressings research in this area is generally poor. However, each category of dressings has particular characteristics that aid selection. Nonadhesive dressings are simple, inexpensive, and well tolerated. Foam and alginate dressings are highly absorbent and effective for heavily exuding wounds. Hydrogels facilitate autolysis and may be beneficial in managing ulcers containing necrotic tissue. Dressings containing inidine and silver may aid in managing wound infection. Occlusive dressings should be avoided for infected wounds. All dressings require frequent change for wound inspection. Heavily exudating ulcers require frequent change to reduce maceration of surrounding skin. Dressing choice should be guided by the characteristics of the ulcer, the requirements of the patient, and costs.

Spinal subdural haematoma: how relevant is the INR?

STUDY DESIGN

Case report.

OBJECTIVE

To report a rare cause of spinal cord compression.

SETTING

University Hospital, Wales, UK.

CASE REPORT

A 67-year-old gentleman on oral anticoagulation for atrial fibrillation presented with a 4-h history of progressive loss of sensation and weakness in both legs; there was no history of trauma. On examination, he had a flaccid paraplegia with altered sensation in the L1,2,3 dermatomes and complete anaesthesia in the L4,5 distribution. Knee and ankle jerk reflexes were absent, plantars were equivocal and anal sphincter tone was reduced. The patient's international normalized ratio (INR) was 4.1. An MR scan showed an extensive intradural haematoma compressing the cauda equina. The anticoagulation was reversed and an urgent T12-L2 laminectomy was performed; findings were a circumferential haematoma at L1 extending in the anterior canal between T10 and L3. The patient had an uneventful postoperative course generally, but at 1 week there was no neurological recovery.

CONCLUSION

This case highlights that anticoagulation even when well controlled is not without risk. This is particularly of concern as the number of patients receiving long-term anticoagulation therapy has doubled between 1993 and 1998.

Noradrenaline-induced lipolysis in adipose tissue is suppressed at hibernation temperatures in ground squirrels

Responsiveness of white adipose tissue (WAT) and brown adipose tissue (BAT) from hibernating and nonhibernating golden-mantled ground squirrels (Spermophilus lateralis) to the lipolytic action of the sympathetic neurotransmitter, noradrenaline, was tested in vitro at temperatures characteristic of deep torpor (5 degrees C) and euthermia (37 degrees C). Noradrenaline-stimulated lipolysis, as indicated by WAT glycerol release, of tissue from hibernating ground squirrels was six- to ten-fold greater at 37 degrees C than at 5 degrees C. Noradrenaline was ineffective in increasing lipolysis at 5 degrees C. Noradrenaline-stimulated lipolysis in BAT was similarly suppressed at 5 degrees C. Noradrenaline-stimulated lipolysis was little affected by temperature change below approximately 15 degrees C but strongly correlated with temperature above approximately 15 degrees C. Noradrenaline-induced lipolysis of WAT from nonhibernating and hibernating ground squirrels did not differ at an incubation temperature of 5 degrees C. We conclude that noradrenaline-stimulated WAT lipolytic activity is markedly suppressed at the low temperatures characteristic of deep torpor and that there is no 'hibernation-specific' adaptation of WAT to enhance its responsiveness to noradrenaline at low tissue temperatures. Temperature dependence of noradrenaline-stimulated lipolysis may in part account for the shift from lipid to carbohydrate metabolism during the earliest stage of arousal from deep torpor.

Patient characteristics and prescription patterns of atypical antipsychotics among patients with schizophrenia

BACKGROUND

Schizophrenia, one of the leading causes of disability, contributes substantially to the use of medical and mental health services. The treatment of schizophrenia is therefore particularly important to reduce deficits across a large number of neurocognitive domains.

OBJECTIVE

To describe the prescription (e.g. initiation and switching) patterns of atypical antipsychotic agents and examine the extent to which patient sociodemographic and clinical characteristics are associated with the prescription patterns of atypical antipsychotics among patients with schizophrenia.

METHODS

Using unique data sources from the Veterans Health Administration (VA), the study identified 89 107 patients with schizophrenia based on at least one inpatient or more than or equal to two outpatients' ICD-9-CM codes (> or =7 days apart). We defined a prior 6-month (1/1/99 to 6/30/99) and a post 6-month (7/1/99 to 12/31/99) period to describe patterns of initiation and switching of atypical antipsychotics.

RESULTS

Only a small number of patients were on clozapine (1.8%) and quetiapine (1.4%). More patients were prescribed olanzapine (23%) than risperidone (20%) (P < 0.001). Compared with patients who were on risperidone, those who were on olanzapine were younger (P < 0.001), more likely Hispanic (P < 0.001), more likely married (P < 0.05), had more service-connected disability (P < 0.001), had fewer numbers of physical comorbidities (P < 0.001), and a lower body mass index (BMI) (P < 0.05).

CONCLUSION

Olanzapine and risperidone appear to be prescribed to patients with different sociodemographic and clinical characteristics. Future research needs to explore the reasons for those differences.

Identifying patient and physician characteristics that affect compliance with antihypertensive medications

BACKGROUND

Compliance with antihypertensive medications is essential to the clinical management of hypertension. Poor compliance with antihypertensive medications has often been associated with treatment failure and disease progression.

OBJECTIVE

To identify patient and prescriber characteristics that may influence compliance with antihypertensive medications.

METHOD

We used pharmacy records within the Veterans Health Administration, a database which included 1292 patients and 656 physicians over a 2-year time period from April 1, 1996, to April 1, 1998. The level of compliance with antihypertensive medications was assessed using a measure developed for this purpose within the Administration. Three separate ordinary least squares regression models were conducted to ascertain the effects of patient and physician characteristics on compliance.

RESULTS

Despite the importance of compliance in the clinical management of hypertension, poor compliance with antihypertensive drug treatment was still widespread. Patients who were younger and less active in their treatment decisions tended to be less compliant (P < 0.05 and 0.05, respectively). Health care providers who were older, residents in speciality care, and physicians (as compared with non-physicians) had patients who were also less likely to be compliant (P < 0.01, 0.01, and 0.05, respectively).

CONCLUSION

These findings suggest that in order to increase the effectiveness of medical care for hypertension, it is important to improve compliance with antihypertensive agents.

Noninvasive transcutaneous determination of access blood flow rate

BACKGROUND

Current indicator dilution techniques for determining the vascular access blood flow rate (Qa) require reversal of the dialysis blood lines and are time consuming. We have recently described an indicator dilution technique for determining Qa using a novel optical transcutaneous hematocrit (Hct) sensor that does not require reversal of the dialysis lines, and have validated the accuracy of this method (TQa) in vitro.

METHODS

This study compared results using the TQa method with those obtained using a similar indicator dilution technique but which required reversal of the dialysis lines (HD01 Monitor, Transonic Systems, Ithaca, NY, USA) during routine hemodialysis in 59 patients (25 native fistulas and 34 synthetic grafts). The sensor for the TQa method was placed on the skin directly over the access to measure changes in Hct approximately 25 mm downstream of the venous needle. A single 30 mL bolus of saline was infused into the dialyzer venous line over approximately six seconds without reversal of the dialysis blood lines, and the vascular access flow rate was calculated using indicator dilution methods from the time-dependent decrease in the Hct downstream of the venous needle. Two additional small-scale studies were performed to assess the effect skin pigmentation and to evaluate further the reproducibility of the TQa method.

RESULTS

Qa values determined by the TQa method were highly correlated with those determined by the HD01 method (N = 72, R2 = 0.948, P < 0.001) over the range of 153 to 2,042 mL/min. There was no significant difference between vascular access flow rates determined by the TQa method and those determined by the HD01

METHOD

Results from one small-scale study showed that the relationship between Qa values determined by the TQa and the HD01 methods was similar when tested only among black patients (N = 12), suggesting that skin pigmentation is not an important determinant of the accuracy of the TQa

METHOD

The second small-scale study showed that the intratreatment coefficient of variation for the TQa method was 7.8 +/- 5.6% (N = 14).

CONCLUSIONS

: These results show that transcutaneous measurement of Qa is an accurate, simple, and fast technique for determining Qa without requiring the reversal of the dialysis blood lines.

Powdery Mildew Caused by Erysiphe pisi on Alfalfa in Idaho and Oregon

During July to November 2000, alfalfa (Medicago sativa L.) plants with powdery mildew symptoms were observed in commercial hay and seed fields, research plots, and a greenhouse in southwestern Idaho (Canyon County) and eastern Oregon (Malheur County). Affected leaves and stems showed white, effuse, dense, amphigenous mycelium bearing Oidium conidia, often with necrotic, brown blotches or streaks. In July, symptoms and signs were found mostly on the lower stems and leaves, but by October, all aerial parts of the plants were involved. Based on location of the mycelium and the conidiophore and conidial characteristics, the fungus was identified as Erysiphe pisi (J. C. David, personal communication). Cleistothecia were not observed. Natural incidence of the disease, which varied from less than 5% infected plants in July to more than 90% infected plants in November, was observed in commercial fields of cvs. Pioneer 53V08 (hay), Sparta (hay), and DS 907 (seed); in research (seed production) plots on cvs. Alfagraze, Anchor, Barrier, Beaver, Cut'N'Graze, Rambler, and Rangelander; and in the greenhouse on cvs. Aggressor, Archer II, Nemagone, Pecos, and Robust. Greenhouse inoculations by dusting with conidia from infected alfalfa plants (cv. Pioneer 53V08) demonstrated the susceptibility of alfalfa cvs. Affinity, Amerigraze, Innovator, and Salado and pea (Pisum sativum L.) cvs. Aladdin, Badger, Bolero, Cabree, Dwarf Gray Sugar, Early Perfection, Encore, Lazor, Maestro, Melting Sugar, Novella, Pursur, Somerwood, Spring, Stampede, and Sugar Ann. Red clover (Trifolium pratense L.) cvs. Redland, Redland II, and Premier showed positive but limited symptoms (smaller colonies, scant mycelium, and brown necrosis) following inoculation. Uninoculated control plants remained free from powdery mildew. Previous reports of powdery mildew on alfalfa in the United States (2) have attributed it to E. polygoni (Massachusetts and Wyoming) or Oidium sp. (Hawaii). Recently, powdery mildew caused by E. pisi was reported from alfalfa in research nurseries and greenhouses in Wisconsin (1). To our knowledge, this is the first report of occurrence of powdery mildew of alfalfa caused by E. pisi in the northwestern U.S., and may constitute a potential new problem for hay and seed production in this region. References: (1) J. I. Edmunds et al. Plant Dis. 82:832, 1998. (2) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. APS Press, St. Paul, MN.

Emergency Medical Services Outcomes Project (EMSOP) II: developing the foundation and conceptual models for out-of-hospital outcomes research

Development of methodologically acceptable outcomes models for emergency medical services (EMS) is long overdue. In this article, the Emergency Medical Services Outcomes Project proposes a conceptual framework that will provide a foundation for future EMS outcomes research. The "Episode of Care Model" and the "Out-of-Hospital Unit of Service Model" are presented. The Episode of Care Model is useful in conditions in which interventions and outcomes, especially survival and major physiologic dysfunction, are linked in a time-dependent manner. Conditions such as severe trauma, anaphylaxis, airway obstruction, respiratory arrest, and nontraumatic cardiac arrest are amenable to this methodology. The Out-of-Hospital Unit of Service Model is essentially a subunit of the Episode of Care Model. It is valuable for evaluating conditions that have minimal-to-moderate therapeutic time dependency. This model should be used when studying outcomes limited to the out-of-hospital interval. An example of this is pain management for injuries sustained in motor vehicle crashes. These models can be applied to a wide spectrum of conditions and interventions. With the scrutiny of health care expenditures ever increasing, the identification of clinical interventions that objectively improve patient outcome takes on growing importance. Therefore, the development, dissemination, and use of meaningful methodologies for EMS outcomes research is key to the future of EMS system development and maintenance.

Clinical impact of interlaboratory variation in international normalized ratio determinations

Variation among laboratories and point-of-care (POC) devices in International Normalized Ratio (INR) determinations for individual patients in the same community was studied. For each patient, blood samples obtained from a single venipuncture followed by a finger stick were tested at three laboratories and with two POC devices. A nonparametric analysis of variance and regression analysis were used to compare INRs across sources. The potential clinical impact of differences between pairs of INR readings (i.e., whether a difference was likely to result in a change in therapy) was evaluated. Complete data were obtained and analyzed for 41 patients. Of the five sources of INRs, results from two laboratories and one POC device were significantly similar. Results from one laboratory and one POC device were significantly different from the other results. Variation between INR readings from two different sources might have resulted in a change in therapy 10-30% of the time. Variations occurred in INR readings among three laboratories and two POC devices and could have led to a substantial number of inappropriate changes in therapy.

Systemic fat and thrombus embolization in patients undergoing total knee arthroplasty with regional heparinization

A double-blind, randomized, controlled study was undertaken to determine if a technique of intraoperative anticoagulation would decrease the incidence or severity of venous embolization after tourniquet release during total knee arthroplasty. Sixty-six patients were randomized to receive either the heparin or placebo treatment. Transesophageal echocardiography was performed before and after tourniquet release to detect embolic material in the right atrium. Transient opacification of the right atrium was observed in all patients within the first 30 seconds after tourniquet release. Regional limb heparinization is not effective in reducing the intensity of right atrium opacification because much of the echogenic material was composed of fat rather than thrombus.

Self-reported and clinical oral health in users of VA health care

BACKGROUND

This article describes the oral health of users of Veterans Administration (VA) health care using both clinical and self-report measures, and models relationships between these measures and self-perceived oral health.

METHODS

We conducted a cross-sectional study of 538 male users of VA outpatient care in the Boston area. Questionnaires assessed self-reported oral health, oral-specific health-related quality of life, health behaviors, and sociodemographic information. Clinical data were collected on oral mucosa status, number of teeth and root tips, dental caries, and periodontal treatment need. We report clinical and self-reported oral health status by age group (era of military service). We regressed models of self-perceived oral health on clinical indices and self-reported measures of the impact of oral health on daily life, adjusting for sociodemographic characteristics and health behavior.

RESULTS

Among those participants aged 65 to 91 years old, 2.8%, 18.7%, and 41.5% rated their oral health as excellent, very good, or good, respectively. Among 50- to 64-year-old men, the corresponding values were 1.4%, 18.5%, and 40.4%, while among those aged 22 to 49 years old, the values were 2.3%, 17%, and 34.1%. Tooth loss was common among users of VA care; 34% of those aged 65-90 years, 28% of those aged 50-64 years, and 8% of those aged 25-49 years had no teeth. Periodontal treatment needs were uniformly high among persons with teeth; mild mucosal change was common, and 10% had root tips. Regression models showed self-perceived oral health was better in persons with more teeth and recent dental treatment, and worse with tooth mobility, coronal decay, and more medical problems. Measures of the impact of oral conditions on daily life added significantly to the amount of explained variance in self-perceived oral health.

CONCLUSIONS

Clinical conditions and the impact of oral health on daily life are important determinants of self-perceived oral health.

Genetic analysis of testis weight and fertility in an interspecies hybrid congenic strain for Chromosome X

A hybrid congenic strain, C57BL/6J.SPRET-Hprt(a), carrying 17 map units of Chromosome (Chr) X from Mus spretus on a background of C57BL/6J. has the novel phenotype of low fertility associated with small testis weight. In histological cross-section, many of the tubules in the testes of these congenic mice are empty except for Sertoli cells, while the other tubules appear to be normal. The gene, interspecific hybrid testis weight 1 (Ihtw1) causing this phenotype, has been fine mapped by using the strategy of generating subcongenic strains from recombinants within the congenic region. Genetic and phenotypic analysis of the subcongenic strains has defined a critical region of 1.8 map units for Ihtw1. This region of the genetic map is orthologous to the region on human Chr X containing the gene for the Borjeson-Forssman-Lehman syndrome, an inherited disease in which males show microorchidism.

Smokeless tobacco extracts modulate exogenous gene expression in early passage cultured human oral epithelial cells: an in vitro system to study chemical and viral enhancer/promoter interaction

The increased risk for cancers of the oral cavity from smokeless tobacco use may reflect the interaction of tobacco with genetic factors, such as oncogenes, and other exogenous factors, such as viruses. An in vitro system was developed based on expression of the chloramphenicol acetyltransferase (CAT) reporter gene to study interactions of chemical treatments with viral enhancer/promoters in early passage cell cultures of oral cavity-derived epithelial cells. Expression of CAT in transfected cells was significantly greater with CAT under the control of the cytomegalovirus immediate early enhancer/promoter (pCEP4/CAT) compared to the Rous sarcoma virus long terminal repeat enhancer/promoter (pRSV-cat) and the simian virus 40 (SV40) early promoter (pSV2-cat). No CAT expression was detected using corresponding control plasmids without the CAT reporter gene. Using this system, smokeless tobacco extracts prepared from either dry snuff or moist snuff delayed maximum CAT expression from Day 4 to Day 5, with sustained, significantly increased CAT expression at 12 days compared to the declining CAT expression observed in untreated control cells. Smokeless tobacco extracts can modulate intracellular gene expression. This system provides an in vitro model to test specificity of toxic agents on enhancer/promoter activity and the interaction on exogenous gene expression.

Some local environmental effects on mercury emission and absorption at a soil surface

The purpose of this study was to quantify effects of some local environmental variables on the soil surface exchanges of total gaseous mercury (TGM), under controlled conditions. A dynamic flux chamber with a Tekran mercury analyzer was used to quantify TGM emissions from, and absorption by, a clean, fine sandy loam soil with very low mercury content inside of a building and in a low TGM environment, outside. Simultaneous measurements of mercury flux, air and soil temperatures, ozone concentration, humidity, soil moisture and solar radiation were made. Controlled applications of water were made to change soil H2O content and measure the response of mercury flux. Air-soil exchanges were highly dependent on soil temperature (r2 = 0.78) and the mercury concentration gradient between the TGM in the soil pores and the ambient TGM above the soil surface (r2 = 0.98 for absorption and r2 = 0.408 for emissions). Correlations with air temperature and ozone levels are explained by the relationships of these variables with soil temperature. No detectable correlation was found with solar radiation or humidity. Wet soil maintained higher rates of soil TGM emission and decreased soil absorption. Emissions increased with increasing soil H2O, peaked at approximately field capacity, and then decreased slightly until saturation.