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At least 721 records · Page 40Linked to original sources

PubMed2002

Accurate localization of intracavitary brachytherapy applicators from 3D CT imaging studies.

PURPOSE: To present an accurate method to identify the positions and orientations of intracavitary (ICT) brachytherapy applicators imaged in 3D CT scans, in support of Monte Carlo photon-transport simulations, enabling accurate dose modeling in the presence of applicator shielding and interapplicator attenuation. MATERIALS AND METHODS: The method consists of finding the transformation that maximizes the coincidence between the known 3D shapes of each applicator component (colpostats and tandem) with the volume defined by contours of the corresponding surface on each CT slice. We use this technique to localize Fletcher-Suit CT-compatible applicators for three cervix cancer patients using post-implant CT examinations (3 mm slice thickness and separation). Dose distributions in 1-to-1 registration with the underlying CT anatomy are derived from 3D Monte Carlo photon-transport simulations incorporating each applicator's internal geometry (source encapsulation, high-density shields, and applicator body) oriented in relation to the dose matrix according to the measured localization transformations. The precision and accuracy of our localization method are assessed using CT scans, in which the positions and orientations of dense rods and spheres (in a precision-machined phantom) were measured at various orientations relative to the gantry. RESULTS: Using this method, we register 3D Monte Carlo dose calculations directly onto post insertion patient CT studies. Using CT studies of a precisely machined phantom, the absolute accuracy of the method was found to be +/-0.2 mm in plane, and +/-0.3 mm in the axial direction while its precision was +/-0.2 mm in plane, and +/-0.2 mm axially. CONCLUSION: We have developed a novel, and accurate technique to localize intracavitary brachytherapy applicators in 3D CT imaging studies, which supports 3D dose planning involving detailed 3D Monte Carlo dose calculations, modeling source positions, shielding and interapplicator shielding, accurately.

Brachytherapy↗

PubMed2004

Intraluminal ultrasound applicator compatible with magnetic resonance imaging "real-time" temperature mapping for the treatment of oesophageal tumours: an ex vivo study.

High intensity ultrasound has shown considerable ability to produce precise and deep thermal coagulation necrosis. Focused, cylindrical, spherical or plane transducers have been used to induce high temperatures in tissues to coagulate proteins and kill cells. Recently magnetic resonance imaging (MRI) has been used, with extracorporeal or intracavitary focused transducers and cylindrical interstitial applicators, to monitor temperature distribution and provide feedback during heating procedures. If intraluminal applicators are used, the active part is in contact with the region of interest and it is essential to provide an accurate view of heat deposition and the extent of coagulation necrosis close to the transducer. The purpose of this study was to develop a 10 mm diameter intraluminal ultrasound applicator, designed to treat oesophageal cancers and compatible with MRI "real-time" temperature mapping. The active part of the ultrasound applicator, covered by a latex balloon, is a 15 X 8 mm2 plane transducer, which is in contact with the tumours during treatment. Each ultrasound exposure generates coagulation necrosis, in an area with the approximate shape of a rectangular parallelepiped up to 10 mm deep. When the exposures were repeated by rotating the applicator on its axis, sector-based or cylindrical volumes of necrosis could be produced, matching the shape of oesophageal cancers. Ex vivo trials were performed to demonstrate the applicator's compatibility with a clinical MRI scanner (1.5 T). MRI signals were acquired without any magnetic susceptibility distortion, even close to the applicator. Fast (0.72 images per second) 2D temperature mapping was performed during ultrasound exposure, using temperature-related proton resonance frequency shift at a resolution of 0.5 degrees C. Coagulation necrosis viewed with inversion recovery sequences, were in good agreement with the qualitative macroscopic observations made for the few cases tested in this study.

Agar↗

PubMed2005

Curvilinear transurethral ultrasound applicator for selective prostate thermal therapy.

Thermal therapy offers a minimally invasive option for treating benign prostatic hyperplasia (BPH) and localized prostate cancer. In this study we investigated a transurethral ultrasound applicator design utilizing curvilinear, or slightly focused, transducers to heat prostatic tissue rapidly and controllably. The applicator was constructed with two independently powered transducer segments operating at 6.5 MHz and measuring 3.5 mm x 10 mm with a 15 mm radius of curvature across the short axis. The curvilinear applicator was characterized by acoustic efficiency measurements, acoustic beam plots, biothermal simulations of human prostate, ex vivo heating trials in bovine liver, and in vivo heating trials in canine prostate (n=3). Each transducer segment was found to emit a narrow acoustic beam (max width <3 mm), which extended the length of the transducer, with deeper penetration than previously developed planar or sectored tubular transurethral ultrasound applicators. Acoustic and biothermal simulations of human prostate demonstrated three treatment schemes for the curvilinear applicator: single shot (10 W, 60 s) schemes to generate narrow ablation zones (13 x 4 mm, 52 degrees C at the lesion boundary), incremental rotation (10 W, 10 degrees/45 s) to generate larger sector-shaped ablation zones (16 mm x 180 degrees sector), and rotation with variable sonication times (10 W, 10 degrees/15-90 s) to conform the ablation zone to a predefined boundary (9-17 mm x 180 degrees sector, 13 min total treatment time). During in vivo canine prostate experiments, guided by MR temperature imaging, single shot sonications (6 W/transducer, 2-3 min) with the curvilinear applicator ablated 20 degree sections of tissue to the prostate boundary (9-15 mm). Multiple adjacent sonications ("sweeping") ablated large sections of the prostate (180 degrees) by using the MR temperature imaging to adjust the power (4-6.4 W/transducer) and sonication time (30-180 s) at each 10 degrees rotation such that the periphery of the prostate reached 52 degrees C before the next rotation. The conclusion of this study was that the curvilinear applicator produces a narrow and penetrating ultrasound beam that, when combined with image guidance, can provide a precise technique for ablating target regions with a contoured outer boundary, such as the prostate capsule, by rotating in small steps while dynamically adjusting the net applied electrical power and sonication time at each position.

Acoustics↗

PubMedDate not supplied

Dosimetry of Sr-90 ophthalmic applicators.

Sr-90 ophthalmic applicators are commonly used for the treatment of superficial eye disorders. Although a variety of dosimetric devices such as film, thermoluminescent dosimeters (TLD's), ion chambers, and radiochromic foils have been used to measure the peak dose at the applicator surface, there is no internationally agreed upon calibration procedure. Recently, large discrepancies among calibrations of the same applicator at three institutions have been reported. Here we describe a technique to obtain the peak dose rate at the applicator surface using LiF TLD's. The technique can be used for the calibration of flat as well as curved surface applicators. Results for two flat and three concave applicators are presented. Our measurement of the surface dose rate for one of the flat applicators is compared with those obtained by four other institutions, each using different dosimetric devices.

Calibration↗

PubMed1997

Tonsillar application of killed Streptococcus mutans induces specific antibodies in rabbit saliva and blood plasma without inducing a cross-reacting antibody to human cardiac muscle.

When Streptococcus mutans cells are injected into the skeletal muscle of rabbits, an antibody against human cardiac muscle, as well as an anti-S. mutans antibody, is induced in blood plasma. Our previous study showed that when sheep erythrocytes are applied to palatine tonsils, an antibody against the applied cells is induced both in blood plasma and saliva. This antibody has no activity against cardiac muscle. It is not clear, however, if S. mutans application to the tonsils evokes an antibody response against cardiac muscle. In this study, we immunized rabbits against S. mutans or Streptococcus sobrinus by tonsillar application or by intramuscular injection every 3 days for 6 weeks. Tonsillar applications of formalin-killed cells of S. mutans induced saliva immunoglobulin A (IgA) and blood plasma IgG to the applied cells. In contrast, intramuscular injection of such cells induced only blood plasma IgG. When the route of immunization was intramuscular injection, antibodies in blood plasma cross-reacted with cardiac muscle. By enzyme-immunohistochemistry and Ouchterlony immunodiffusion tests, no cross-reaction to cardiac muscle was observed with the antibody in saliva or in blood plasma after the tonsillar applications. Western blotting of the S. mutans antigen showed that blood plasma from rabbits injected with S. mutans reacted with antigens of 46, 52, 62, and 85 kDa, while that from rabbits subjected to tonsillar application of S. mutans did not react with these bands. Similar results were obtained for S. sobrinus applications. Thus, tonsillar applications of mutants group streptococci induce antibodies differing in antigen specificity and do not induce any cross-reacting antibody to cardiac muscle.

Animals↗

PubMed1991

Study of United Kingdom product licence applications containing new active substances, 1987-9.

OBJECTIVES: To investigate the fate of product licence applications containing new active substances in relation to their degree of innovation and therapeutic category. To assess the numbers of volunteers and patients exposed to a new active substance when marketing autorisation is first sought. DESIGN AND SETTING: Observational study of records for each licence application submitted to the United Kingdom licensing authority for marketing authorisation from 1987 to 1989. SUBJECTS: 118 product licence applications containing one or more new active substances. MAIN OUTCOME MEASURES: Success of application for product licence as assessed by the decision of the Committee on Safety of Medicines to advise the granting of a licence (with or without conditions) or provisionally advise its refusal on the grounds of quality, safety, or efficacy. Assessment of numbers of volunteers and patients exposed to each substance during premarketing studies and clinical trials, and the numbers of treated patients available for an assessment of safety. RESULTS: 118 relevant product licence applications were submitted during the review. Although 60% (52/86) of semi-innovative products fell into one of three therapeutic categories (cardiovascular, central nervous system, or anti-infective agents), only 41% (13/32) of fully innovative products fell into these categories. 47 applications were granted (conditionally or unconditionally) but the success rate for fully innovative products (56%, 18/32) was greater than that for semi-innovative products (34%, 29/86). The number of volunteers and patients exposed to a new product at submission varied widely and tended to be greater for successful applications. CONCLUSION: The results suggest a broadening of the pharmaceutical industry's research and development programmes and that a more liberal licensing policy exists for fully innovative products than for semi-innovative products. The relatively limited exposure of patients to new active substances at licensing underlines the importance of rigorous postmarketing surveillance.

Consumer Product Safety↗

PubMed1995

Medical school applicants from ethnic minority groups: identifying if and when they are disadvantaged.

OBJECTIVE: To assess whether people from ethnic minority groups are less likely to be accepted at British medical schools, and to explore the mechanisms of disadvantage. DESIGN: Prospective study of a national cohort of medical school applicants. SETTING: All 28 medical schools in the United Kingdom. SUBJECTS: 6901 subjects who had applied through the Universities' Central Council on Admissions in 1990 to study medicine. MAIN OUTCOME MEASURES: Offers and acceptance at medical school by ethnic group. RESULTS: Applicants from ethnic minority groups constituted 26.3% of those applying to medical school. They were less likely to be accepted, partly because they were less well qualified and applied later. Nevertheless, taking educational and some other predictors into account, applicants from ethnic minority groups were 1.46 times (95% confidence interval 1.19 to 1.74) less likely to be accepted. Having a European surname predicted acceptance better than ethnic origin itself, implying direct discrimination rather than disadvantage secondary to other possible differences between white and non-white applicants. Applicants from ethnic minority groups fared significantly less well in 12 of the 28 British medical schools. Analysis of the selection process suggests that medical schools make fewer offers to such applicants than to others with equivalent estimated A level grades. CONCLUSIONS: People from ethnic minority groups applying to medical school are disadvantaged, principally because ethnic origin is assessed from a candidate's surname; the disadvantage has diminished since 1986. For subjects applying before A level the mechanism is that less credit is given to referees' estimates of A level grades. Selection would be fairer if (a) application forms were anonymous; (b) forms did not include estimates of A level grades; and (c) selection took place after A level results are known.

Black or African American↗

PubMed2000

Difficulties with anonymous shortlisting of medical school applications and its effects on candidates with non-European names: prospective cohort study.

OBJECTIVE: To assess the feasibility of anonymous shortlisting of applications for medical school and its effect on those with non-European names. DESIGN: Prospective cohort study. SETTING: Leeds school of medicine, United Kingdom. SUBJECTS: 2047 applications for 1998 entry from the United Kingdom and the European Union. INTERVENTION: Deletion of all references to name and nationality from the application form. MAIN OUTCOME MEASURES: Scoring by two admissions tutors at shortlisting. RESULTS: Deleting names was cumbersome as some were repeated up to 15 times. Anonymising application forms was ineffective as one admissions tutor was able to identify nearly 50% of candidates classed as being from an ethnic minority group. Although scores were lower for applicants with non-European names, anonymity did not improve scores. Applicants with non-European names who were identified as such by tutors were significantly less likely to drop marks in one particular non-academic area (the career insight component) than their European counterparts. CONCLUSIONS: There was no evidence of benefit to candidates with non-European names of attempting to blind assessment. Anonymising application forms cannot be recommended.

Cohort Studies↗

PubMedDate not supplied

Radiofrequency ablation using perfused needle electrodes - study of intermittent and continuous triple needle application ex vivo.

To increase necrotic zones, bovine livers were treated by means of three parallel-oriented radiofrequency ablation (RFA) needles spaced at 3 cm using a puncture guide. The triple application was varied as a continuous and intermittent energy application compared to a single needle applicator. In all three study arms the applied energy (60 W) and the perfusion rate (240 ml/h) were kept constant. After treatment the smallest necrosis diameter was determined. In addition, temperature and the device's power output were monitored. Our study shows that synchronous use of three RFA application needles achieves significantly larger necrosis zones ex vivo than does single needle application. Intermittent energy application heats up the necrosis faster and more evenly with highest average temperature than continuous energy application.

Animals↗

PubMed1996

Decreased aqueous-flare reaction to repeated applications of prostaglandin E2 to the cornea in pigmented rabbits.

To evaluate the effect of single or repeated topical applications of prostaglandin E2 (PGE2) to the cornea on the blood-aqueous barrier, we have measured the extent of flare in the anterior chamber of rabbit eyes at various time intervals. PGE2 was applied to the cornea for 4 min with the use of a glass cylinder in pigmented rabbits. Aqueous flare was measured by a laser flare cell meter. The flare intensity following the second application of 25 or 50 micrograms/ml of PGE2 was smaller than that following the first application. When 50 micrograms/ml of PGE2 was applied every day for 6 days, the flare intensity decreased significantly day by day. After consecutive applications of 10 micrograms/ml of PGE2 at hourly intervals, flare intensity increased up to 3 h, remained elevated from 3 to 5 h, and decreased thereafter. Repeated applications of 10 micrograms/ml of PGE2, every hour for 14 h every Monday, significantly decreased flare intensity week by week. Weekly applications of 50 micrograms/ml of PGE2 did not change flare intensity. This study indicates that the extent of the breakdown of the blood-aqueous barrier in the rabbit eye, as measured by the development of flare in the anterior chamber, is reduced with repeated PGE2 application.

Administration, Topical↗

PubMed1998

Adaptation of rat type II pneumocytes to NO2: effects of NO2 application mode on phosphatidylcholine metabolism.

Previous studies have shown that nitrogen dioxide (NO2) inhalation affects the extracellular surfactant as well as the structure and function of type II pneumocytes. Since in these studies there were great variabilities in oxidant concentration, duration of exposure, and mode of NO2 application, we evaluated the influence of the NO2 application mode on the phospholipid metabolism of type II pneumocytes. Rats were exposed to identical NO2 body doses (720 ppm x h), which were applied continuously (10 ppm for 3 d), intermittently (10 ppm for 8 h per day, for 9 d), and repeatedly (10 ppm for 3 d, 28 d rest, and then 10 ppm for 3 d). Immediately after exposure, type II cells were isolated and evaluated for cell yield, vitality, phosphatidylcholine (PC) synthesis, and secretion. Type II pneumocyte cell yield from animals that had been continuously exposed to NO2 was significantly increased, whereas intermittently and repeatedly treated rats exhibited cell yields that were nonsignificantly enhanced. Vitality of the isolated type II pneumocytes was not affected by the NO2 exposure modes. Continuous application of 720 ppm x h NO2 resulted in increased activity of the cytidine-5-diphosphate (CDP)-choline pathway. After continuous NO2 application, specific activity of choline kinase, cytidine triphosphate (CTP):cholinephosphate cytidylyltransferase, uptake of choline, and pool sizes of CDP-choline and PC were significantly increased over those of controls. Intermittent application of this NO2 body dose also provoked an increase in PC synthesis, but this increase was less prominent than after continuous exposure. After repeated exposure, the synthesis parameters were comparable to those for cells from control animals. Whereas PC synthesis in type II cells was obviously stimulated by NO2, the secretory activity of the cells was reduced. Continuous exposure reduced this activity most, whereas intermittent exposure nonsignificantly reduced this activity as compared with that of controls. The repeated application of NO2 produced no differences. We conclude that type II pneumocytes adapt to NO2 atmospheres depending on the mode of its application, at least for the metabolism of PC and its secretion from isolated type II pneumocytes. Further studies are necessary to determine whether additional metabolic activities will also adapt to NO2 atmospheres, and if these observations are specific for NO2 or represent effects generally due to oxidants.

Adaptation, Physiological↗

PubMed1998

Changes in questions about psychiatric illness asked on medical licensure applications between 1993 and 1996.

OBJECTIVE: This study examined the nature of questions about previous mental illness, physical illness, and substance abuse asked on applications for state medical licensure, partly to determine if questions focused more appropriately on any current, rather than past, disability. METHODS: In 1993 and 1996 the 66 members of the Federation of State Medical Boards of the United States, Inc., were asked to provide copies of the forms they used for medical licensure applications and renewal. The forms were reviewed to determine the presence of questions about previous mental illness, physical illness, and substance abuse and whether the questions specifically addressed the effects of the condition on the ability to practice medicine. RESULTS: On initial licensure applications, medical boards commonly asked questions about mental illness. Seventy-five percent of responding boards did so in 1993, and 80 percent did so in 1996. The proportion of boards that inquired about whether the mental illness might affect the applicant's ability to practice medicine increased from 42 percent in 1993 to 75 percent in 1996. Applicants were asked about substance abuse by 83 percent of the boards in 1993 and by 94 percent in 1996. Boards asked about physical conditions less often than mental conditions but were more likely to ask about physical conditions in 1996 (65 percent) than in 1993 (49 percent). Questions about physical illness almost always addressed the effect of the condition on medical practice. On license renewal requests, medical boards were less likely to ask questions about mental conditions, substance abuse, and physical illnesses than on the original applications. Among boards that asked about mental illness on renewal forms, the proportion of boards that asked about the effect of mental conditions on ability to practice medicine increased from 60 percent in 1993 to 90 percent in 1996. CONCLUSIONS: Medical boards commonly ask questions about mental illness on licensure application and renewal forms. In many states, such questions changed between 1993 and 1996 to emphasize impairment resulting from mental illness and to use similar wording for mental disorders and physical conditions.

Data Collection↗

PubMed2000

Urinalysis of atrazine exposure in farm pesticide applicators.

This study compared three relatively common laboratory methods for the detection of atrazine (a triazine herbicide commonly used in US agriculture), and related metabolites in urine. Ninety-nine samples collected from atrazine applicators within 8 h post application were analyzed. Thirty-seven percent of applicators showed detectable levels (minimum = 1.0 ng/ml) of deethylatrazine (an atrazine metabolite typically found in environmental samples) in their urine, based on gas chromatography-mass spectrometry (GC-MS) analysis (mean = 14.2 ng/ml). Fifty applicator samples were tested using an enzyme-linked immunosorbent assay (ELISA) designed for the mercapturate metabolic product. Most of these samples (80%) had detectable levels of the mercapturate product. A triazine in water ELISA was also used to test several diluted urine samples from atrazine applicators, and all samples were positive for triazines. Mediocre agreements between the three methods indicated that each detected distinct atrazine exposure products. The results indicate that single field applications of atrazine result in measurable pesticide doses to applicators and that the choice of field assay should depend on the exposure product to be evaluated.

Agriculture↗

PubMed2003

Personal digital assistant applications for the healthcare provider.

OBJECTIVE: To review some common medical applications available for personal digital assistants (PDAs), with brief discussion of the different PDA operating systems and memory requirements. Key search terms included handheld, PDA, personal digital assistants, and medical applications. DATA SOURCES: The literature was accessed through MEDLINE (1999-August 2002). Other information was obtained through secondary sources such as Web sites describing common PDAs. DATA SYNTHESIS: Medical applications available on PDAs are numerous and include general drug references, specialized drug references (e.g., pediatrics, geriatrics, cardiology, infectious disease), diagnostic guides, medical calculators, herbal medication references, nursing references, toxicology references, and patient tracking databases. Costs and memory requirements for these programs can vary; consequently, the healthcare provider must limit the medication applications that are placed on the handheld computer. CONCLUSIONS: This article attempts to systematically describe the common medical applications available for the handheld computer along with cost, memory and download requirements, and Web site information. This review found many excellent PDA drug information applications offering many features which will aid the healthcare provider. Very likely, after using these PDA applications, the healthcare provider will find them indispensable, as their multifunctional capabilities can save time, improve accuracy, and allow for general business procedures as well as being a quick reference tool. To avoid the benefits of this technology might be a step backward.

Computers, Handheld↗

PubMed2001

The application of ground force explains the energetic cost of running backward and forward.

We compared backward with forward running to test the idea that the application of ground force to support the weight of the body determines the energetic cost of running. We hypothesized that higher metabolic rates during backward versus forward running would be directly related to greater rates of ground force application and the volume of muscle activated to apply support forces to the ground. Four trained males ran backward and forward under steady-state conditions at eight treadmill speeds from 1.75 to 3.50 m x s(-1). Rates of oxygen uptake were measured to determine metabolic rates, and inverse periods of foot-ground contact (1/tc) were measured to estimate rates of ground force application. As expected, at all eight speeds, both metabolic rates and estimated rates of ground force application were greater for backward than for forward running. At the five slowest speeds, the differences in rates of ground force application were directly proportional to the differences in metabolic rates between modes (paired t-test, P<0.05), but at the three highest speeds, small but significant differences in proportionality were present in this relationship. At one of these three higher speeds (3.0 m x s(-1)), additional measurements to estimate muscle volumes were made using a non-invasive force plate/video technique. These measurements indicated that the volume of muscle active per unit of force applied to the ground was 10+/-3% greater when running backward than forward at this speed. The product of rates of ground force application and estimated muscle volumes predicted a difference in metabolic rate that was indistinguishable from the difference we measured (34+/-6% versus 35+/-6%; means +/- s.e.m., N=4). We conclude that metabolic rates during running are determined by rates of ground force application and the volume of muscle activated to apply support forces to the ground.

Adult↗

PubMed2000

Role of prostaglandin E2 and leukotriene B4 in skin reaction induced by transdermal application of propranolol.

Dermal application of propranolol (PRL) induced formation of erythema and edema, and pseudoeosinophil infiltration in epidermis and dermis at the application site in guinea pigs. We investigated the production of prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) at the application site of PRL and the role of these inflammatory chemical mediators in the occurrence of the skin reactions. PGE2 was found to be produced at the application site slightly after the accumulation of PRL released from the adhesive bandage in the patch test, and the amount of PGE2 increased continuously, with a peak value obtained at 24 h after application. The time-course changes resembled those of delta a* value, the index of erythema formation determined by colorimetric measurement, and edema formation. The production of PGE2 by dermal application of PRL was suppressed by local pretreatment with dexamethasone or indomethacin. However, no notable production of LTB4 was observed at the application site of PRL.

Administration, Cutaneous↗

PubMedDate not supplied

An annotated bibliography of decision analytic applications to health care.

This paper describes 110 applications of decision analysis to health care. Each paper is characterized according to the particular problem it addresses and the methods employed in the application. These applications span 15 years of study and are reported in a widely dispersed literature. Nearly half of the published articles appear in journals with a medical audience and more than 25% of the studies remain unpublished. The major areas of application identified in this review have been the evaluation of alternatives in treatment and health policy planning. Studies discussing conceptual issues in the application of decision analysis represent a substantial portion of those identified. Almost equal numbers of applications involve the use of single and multiattribute utilities in scaling decision outcomes and relatively few apply to group utilities. General discussions of decision analysis methods and applications focused on probability assessments/analyses represent the other major categories of studies cited.

Decision Theory↗

PubMed1999

Dermal transfer of chlorpyrifos residues from residential surfaces: comparison of hand press, hand drag, wipe, and polyurethane foam roller measurements after broadcast and aerosol pesticide applications.

Indoor residential pesticide applications present the potential for human exposures, particularly for small children. Personal contact with target and nontarget surfaces can result in transfer of pesticides to the skin, but the magnitude of such transfer is uncertain. This research compared surface sampling techniques [wipe and polyurethane foam (PUF) roller] with the removal ability of human skin following broadcast and total aerosol release applications of Dursban (Dow Elanco, Midland, MI), a residential formulation containing the insecticide chlorpyrifos. Hands were washed immediately after surface contact, following a protocol that included a laboratory-generated adjustment factor to account for incomplete removal of chlorpyrifos from skin. Chlorpyrifos transfer was similar for hand press and hand drag techniques, averaging approximately 1-6 ng/cm2 of carpet contacted. These amounts represented < 1% of the amount of chlorpyrifos deposited on the surfaces 3.5 hr earlier. Chlorpyrifos transfer from carpet to skin was 23-24 times lower than for wipe sampling and 33-36 times lower than for PUF roller sampling (p = 0.0007 and p = 0.0006 for broadcast and aerosol applications, respectively). Hand press sampling removed approximately 4.5 times less chlorpyrifos from nontarget furniture surfaces (12 ng/cm2) than did wipe sampling (56 ng/cm2; p = 0.009). Chlorpyrifos residues on carpet were substantially higher after broadcast applications than after aerosol applications, but residues on such nontarget surfaces as furniture were substantially higher for the aerosol application. This study indicates that human skin removes substantially less residue from carpets and furniture than either conventional wipe or PUF roller sampling methods following residential pest control applications of chlorpyrifos. Although this paper focuses on quantifying residue transfer from surface to skin using different surface sampling techniques, no attempt is made to quantify the amount of chlorpyrifos residue that is subsequently absorbed.

Aerosols↗