Translating Research into Agile Development (TRIAD): Development of Electronic Health Record Tools for Primary Care Settings.

OBJECTIVES: This article describes a method for developing electronic health record (EHR) tools for use in primary care settings. METHODS: The "Translating Research into Agile Development" (TRIAD) method relies on the close collaboration of researchers, end users, and development teams. This five-step method for designing a tailored EHR tool includes (1) assessment, observation, and documentation; (2) structured engagement for collaboration and iterative data collection; (3) data distillation; (4) developmental feedback from clinical team members on high-priority EHR needs and input on design prototypes and EHR functionality; and (5) agile scrum sprint cycles for prototype development. RESULTS: The TRIAD method was used to modify an existing EHR for behavioral health clinicians (BHCs) embedded with primary care teams, called the BH e-Suite. The structured engagement processes stimulated discussions on how best to automate BHC screening tools and provide goal tracking functionality over time. Data distillation procedures rendered technical documents, with information on workflow steps, tasks, and associated challenges. In the developmental feedback phase, BHCs gave input on screening assessments, scoring needs, and other functionality to inform prototype feature development. Six 2-week sprint cycles were conducted to address three domains of prototype development: assessment and documentation needs, information retrieval, and monitoring and tracking. The BH e-Suite tool resulted with eight new EHR features to accommodate BHCs' needs. CONCLUSION: The TRIAD method can be used to develop EHR functionality to address the evolving needs of health professionals in primary care and other settings. The BH e-Suite was developed through TRIAD and was found to be acceptable, easy to use, and improved care delivery during pilot testing. The BH e-Suite was later adopted by OCHIN Inc., which provided the tool to its 640 community health centers. This suggests that the TRIAD method is a promising research and development approach.

Toric intraocular lens outcomes with a new protocol for IOL selection and implantation.

INTRODUCTION: The published literature on toric intraocular lenses (IOL) reports postoperative refractive cylinder less than or equal to 0.5 D in anywhere from 25% to 100% of implantations with both the Acrysof® Toric and Tecnis® Toric IOL, depending upon the article. However, the majority of articles tend to cite rates between 70% and 80%. PURPOSE: The purpose was to evaluate my personal outcomes for both models of toric IOL, in terms of one-month postoperative refractive cylinder, after implementation of new methods of IOL selection, calculation and implantation. MATERIALS AND METHODS: The new protocol included measurement of centroid surgically induced astigmatism by vector analysis; calculations using only the Barrett toric calculator, for which the keratometry values were obtained by optical biometry, while the keratometric axes were chosen by visual inspection of the axial topographic map; preoperative marking with the toriCAM cell phone appliance; and corneal incisions performed either manually or with a femtosecond laser. A prospective, observational study was conducted of all consecutive monofocal toric IOL implantations from September 2016 through April 2017. One-month postoperative refractive cylinder was recorded for each eye. RESULTS: Seventy eyes were implanted with monofocal toric IOL, 31 Acrysof® Toric and 39 Tecnis® Toric. Mean postoperative refractive cylinder was 0.48 D (0.00-1.50) for the Acrysof® Toric group and 0.46 D (0.00-1.00) for the Tecnis® Toric group. There were no statistically significant differences in postoperative refractive cylinder between IOL models or methods of incision. The percentage of eyes achieving postoperative refractive cylinder ≤0.50 D ("success") was 77% for the Acrysof® Toric group (82% for laser-assisted and 75% for manual) and 72% for the Tecnis® Toric group (80% for laser-assisted and 69% for manual). CONCLUSION: The implementation of the new protocol resulted in an overall surgical success rate of 77% for Acrysof® Toric IOL and 72% for Tecnis® Toric IOL (P=0.7702). Femtosecond laser-assisted surgery resulted in higher success rates than manual surgery (82% vs. 75% for Acrysof® Toric and 80% vs. 69% for Tecnis® Toric), but these differences were not statistically significant (Acrysof® Toric P=0.7336; Tecnis® Toric P=0.8862).

A computer-based interactive multimedia program to reduce HIV transmission for women with intellectual disability.

BACKGROUND: Despite recent recognition of the need for preventive sexual health materials for people with intellectual disability (ID), there have been remarkably few health-based interventions designed for people with mild to moderate ID. The purpose of this study was to evaluate the effects of a computer-based interactive multimedia (CBIM) program to teach HIV/AIDS knowledge, skills and decision making. METHODS: Twenty-five women with mild to moderate ID evaluated the program. The study used a quasi-experimental within-subjects design to assess the efficacy of the CBIM program. Research participants completed five qualitative and quantitative instruments that assessed HIV knowledge, and decision-making skills regarding HIV prevention practices and condom application skills (i.e. demonstration of skills opening a condom and putting it on a model penis). In addition, 18 service providers who work with women with ID reviewed the program and completed a demographics questionnaire and a professional customer satisfaction survey. RESULTS: Women with ID showed statistically significant increases from pre-test to post-test in all knowledge and skill domains. Furthermore, the statistical gains were accompanied by medium to large effect sizes. Overall, service providers rated the program highly on several outcome measures (stimulation, relevance and usability). CONCLUSIONS: The results of this study indicate the CBIM program was effective in increasing HIV/AIDS knowledge and skills among women with ID, who live both semi-independently and independently, in a single-session intervention. As the CBIM program is not dependent on staff for instructional delivery, it is a highly efficient teaching tool; and CBIM is an efficacious means to provide behavioural health content, compensating for the dearth of available health promotion materials for people with ID. As such, it has a potential for broad distribution and implementation by medical practitioners, and public health offices. People with ID are part of our society, yet continue to be overlooked, particularly in the area of health promotion. Special tools need to be developed in order to address the health disparities experienced by people with ID.

Patterns of lung disease in a "normal" smoking population: are emphysema and airflow obstruction found together?

STUDY OBJECTIVES: We determined whether emphysema demonstrated on high-resolution CT (HRCT) scanning in apparently well smokers is associated with airflow obstruction. INTERVENTIONS: Lung function testing and limited HRCT scanning. DESIGN: Lung function measurements and scans were analyzed independently of each other. We used analysis of covariance to compare FEV(1) and maximum expiratory flow at 50% of vital capacity (MEF(50)) values after suitable corrections, between subjects with and without parenchymal damage (emphysema and/or reduced carbon monoxide transfer coefficient [KCO]), and to compare indexes of parenchymal damage between subjects with and without airflow obstruction. SETTING: Radiology and lung function departments of a district general hospital. PARTICIPANTS: Eighty current cigarette smokers and 20 lifetime nonsmoking control subjects (aged 35 to 65 years) who volunteered following publicity in local media. In all subjects, FEV(1) was > 1.5 L; no subjects were known to have lung disease. MEASUREMENTS AND RESULTS: FEV(1) and MEF(50) were measured spirometrically; static lung volumes were measured by helium dilution and body plethysmography; KCO was measured by a single-breath technique. HRCT scans were analyzed for emphysema by two radiologists. Of smokers, 25% had HRCT emphysema, generally mild; 16.3% and 25% had reduced FEV(1) and MEF(50), respectively; 12.5% had reduced KCO. Smokers with airflow obstruction were not more likely to have parenchymal damage. Smokers with parenchymal damage did not have reduced airway function. Nonsmokers generally had normal airways and parenchyma. CONCLUSIONS: "Normal" smokers with lung damage had either airflow obstruction or parenchymal damage, but not generally both.

N-terminal residues of plasmatocyte-spreading peptide possess specific determinants required for biological activity.

Plasmatocyte-spreading peptide (PSP) is a 23-amino acid cytokine that activates a class of insect immune cells called plasmatocytes. The tertiary structure of PSP consists of an unstructured N terminus (residues 1-6) and a well structured core (residues 7-23). A prior study indicated that deletion of the N terminus from PSP eliminated all biological activity. Alanine substitution of the first three residues (Glu(1)-Asn(2)-Phe(3)) further indicated that only replacement of Phe(3) resulted in a loss of activity equal to the N-terminal deletion mutant. Here, we characterized structural determinants of the N terminus. Adding a hydroxyl group to the aromatic ring of Phe(3) (making a Tyr) greatly reduced activity, whereas the addition of a fluorine (p-fluoro) did not. Substitutions that changed the chirality or replaced the aromatic ring of Phe(3) with a branched aliphatic chain (making a Val) also greatly decreased activity. The addition of a methylene group to Val (making a Leu) partially restored activity, whereas the removal of a methylene group from Phe (phenyl-Gly) eliminated all activity. These results indicated that a branched carbon chain with a methylene spacer at the third residue is the minimal structural motif required for activity. The deletion of Glu(1) also eliminated activity. Additional experiments identified the charged N-terminal amine and backbone of Glu(1) as key determinants for activity.

Structure and activity of the insect cytokine growth-blocking peptide. Essential regions for mitogenic and hemocyte-stimulating activities are separate.

Growth-blocking peptide (GBP) is a 25-amino acid insect cytokine found in Lepidopteran insects that possesses diverse biological activities such as larval growth regulation, cell proliferation, and stimulation of immune cells (plasmatocytes). The tertiary structure of GBP consists of a structured core that contains a disulfide bridge and a short antiparallel beta-sheet (Tyr(11)-Arg(13) and Cys(19)-Pro(21)) and flexible N and C termini (Glu(1)-Gly(6) and Phe(23)-Gln(25)). In this study, deletion and point mutation analogs of GBP were synthesized to investigate the relationship between the structure of GBP and its mitogenic and plasmatocyte spreading activity. The results indicated that deletion of the N-terminal residue, Glu(1), eliminated all plasmatocyte spreading activity but did not reduce mitogenic activity. In contrast, deletion of Phe(23) along with the remainder of the C terminus destroyed all mitogenic activity but only slightly reduced plasmatocyte spreading activity. Therefore, the minimal structure of GBP containing mitogenic activity is 2-23 GBP, whereas that with plasmatocyte spreading activity is 1-22 GBP. NMR analysis indicated that these N- and C-terminal deletion mutants retained a similar core structure to wild-type GBP. Replacement of Asp(16) with either a Glu, Leu, or Asn residue similarly did not alter the core structure of GBP. However, these mutants had no mitogenic activity, although they retained about 50% of their plasmatocyte spreading activity. We conclude that specific residues in the unstructured and structured domains of GBP differentially affect the biological activities of GBP, which suggests the possibility that multifunctional properties of this peptide may be mediated by different forms of a GBP receptor.

Alanine-scanning mutagenesis of plasmatocyte spreading peptide identifies critical residues for biological activity.

Plasmatocyte spreading peptide (PSP) is a 23-amino acid cytokine that induces a class of insect immune cells called plasmatocytes to spread on foreign surfaces. The structure of PSP consists of a disordered N terminus (residues 1-6) and a well-defined core (residues 7-23) stabilized by a disulfide bridge between Cys(7) and Cys(19), hydrophobic interactions, and a short beta-hairpin. Structural comparisons also indicate that the core region of PSP adopts an epidermal growth factor (EGF)-like fold very similar to the C-terminal subdomain of EGF-like module 5 of thrombomodulin. To identify residues important for plasmatocyte spreading activity, we bioassayed PSP mutants in which amino acids were either replaced with alanine or deleted. Within the well-defined core of PSP, alanine replacement of Cys(7) and Cys(19) (C7.19A) eliminated all activity. Alanine replacement of Arg(13) reduced activity approximately 1000-fold in comparison to wild-type PSP, whereas replacement of the other charged residues (Asp(16), Arg(18), Lys(20)) surrounding Cys(19) diminished activity to a lesser degree. The point mutants Y11A, T14A, T22A, and F23A had activity identical or only slightly reduced to that of wild-type PSP. The mutant PSP-(7-23) lacked the entire unstructured domain of PSP and was found to have no plasmatocyte spreading activity. Surprisingly, E1A and N2A had higher activity than wild-type PSP, but F3A had almost no activity. We thus concluded that the lack of activity for PSP-(7-23) was largely due to the critical importance of Phe(3). To determine whether reductions in activity correlated with alterations in tertiary structure, we compared the C7.19A, R13A, R18A, and F3A mutants to wild-type PSP by NMR spectroscopy. As expected, the simultaneous replacement of Cys(7) and Cys(19) profoundly affected tertiary structure, but the R13A, R18A, and F3A mutants did not differ from wild-type PSP. Collectively, these results indicate that residues in both the unstructured and structured domains of PSP are required for plasmatocyte-spreading activity.

Plasmatocyte spreading peptide induces spreading of plasmatocytes but represses spreading of granulocytes.

In most Lepidoptera, plasmatocytes and granulocytes are the two hemocyte classes capable of adhering to foreign targets. Previously, we identified plasmatocyte spreading peptide (PSP1) from the moth Pseudoplusia includens and reported that it induced plasmatocytes to rapidly spread on foreign surfaces. Here we examine whether the response of plasmatocytes to PSP1 was influenced by cell density or culture conditions, and whether PSP1 affected the adhesive state of granulocytes. Plasmatocyte spreading rates were clearly affected by cell density in the absence of PSP1 but spreading was density independent in the presence of PSP1. PSP1 also induced plasmatocytes in agarose-coated culture wells to form homotypic aggregations rather than spread on the surface of culture wells. In contrast, granulocytes rapidly spread in a density independent manner in the absence of PSP1, but were dose-dependently inhibited from spreading by the addition of peptide. An anti-PSP1 polyclonal antibody neutralized the spreading activity of synthetic PSP1. This antibody also neutralized the plasmatocyte spreading activity of granulocyte-conditioned medium, and significantly delayed plasmatocyte spreading when cells were cultured at a high density in unconditioned medium. These results suggested that the spreading activity derived from granulocytes is due in part to PSP1. Pretreatment of plasmatocytes with trypsin had no effect on PSP1-induced aggregation but PSP1-induced aggregations were readily dissociated by trypsin. This suggested that PSP1 is not an adhesion factor but induces adhesion by stimulating a change in the cell surface of plasmatocytes. Synthetic PSP1 also induced aggregation of plasmatocytes from other Lepidoptera indicating that regulation of hemocyte activity by PSP1-related peptides may be widespread. Arch.

Endogenous cortisol and lung damage in a predominantly smoking population.

We examined the association of endogenous corticosteroid status with lung structure and function in a cross-sectional and longitudinal study in response to a recent finding of a relationship between plasma cortisol and rate of annual decline in airway function. We recruited 74 cigarette-smoking and 20 never-smoking volunteers 35 to 65 yr of age after publicity in local media. Exclusion criteria were FEV1 < 1.5 L or a history of airway disease. We performed spirometry and a high resolution CT lung scan and measured CO transfer, serum cortisol, and 24-h urinary cortisol excretion. There were no differences in serum or urinary cortisol between those with and those without low FEV1, low KCO, or high resolution CT (HRCT) emphysema, except that urinary cortisol was 19% higher in subjects with HRCT emphysema (p = 0.05). Log urinary cortisol/body weight was negatively correlated with KCO (p = 0.000) and KCO was lower in the highest tertile of urinary cortisol (p = 0.001). Subjects were restudied after 520 +/- 69 d. Changes in FEV1 and KCO showed no significant correlations with serum or urinary cortisol. We conclude that airway function does not relate to serum or urinary cortisol, but there may be a relationship between cortisol excretion and emphysema.

Structure of the insect cytokine peptide plasmatocyte-spreading peptide 1 from Pseudoplusia includens.

The structure of the recently identified plasmatocyte spreading peptide from the moth Pseudoplusia includens (PSP1) has been determined by NMR spectroscopy. This novel insect cytokine consists of 23 amino acid residues and a single disulfide bond. Torsion angle dynamics calculations utilizing a total of 337 distance constraints yielded an ensemble of 30 structures with an average backbone root mean square deviation for residues 7-22 of 0.18 A from the mean structure. The structure consists of a disordered N-terminal region and a well defined core that is stabilized by numerous hydrophobic interactions and a short beta-hairpin. Structural comparisons confirm that PSP1 adopts an epidermal growth factor (EGF)-like fold with close similarity to the C-terminal subdomain of EGF-like module 5 of human thrombomodulin. The combination of the three-dimensional structure of PSP1 and the extensive literature on EGF-receptor interactions should accelerate the process of identifying the specific residues responsible for receptor binding activity of this family of immunoregulatory peptides.

Plasmatocyte spreading peptide is encoded by an mRNA differentially expressed in tissues of the moth Pseudoplusia includens.

It has long been known that blood cells (hemocytes) are an essential component of the invertebrate immune system, yet little is known about the molecules mediating their function. Recently, we identified plasmatocyte spreading peptide (PSP1) from the moth Pseudoplusia includens which regulates the trafficking and adhesion of a hemocyte subclass called plasmatocytes. Here, we report the cloning of a cDNA (p15) that encodes a PSP1 precursor protein. Northern blot analysis revealed that a homologous prepro-PSP1 mRNA is expressed in fat body, and that other PSP1-related transcripts are expressed in nervous tissue and hemocytes. Coupled in vitro transcription/translation reactions indicated that p15 produces a protein recognized by a PSP1 polyclonal antibody. Immunoblotting experiments further revealed that a putative pro-PSP1 protein is present in P. includens plasma and fat body.

Cigarette smoke inhalation and lung damage in smoking volunteers.

Cigarette smoking is the dominant risk factor for chronic obstructive pulmonary disease (COPD) but only 10-15% of smokers develop the condition. Risk does not relate closely to cumulative cigarette consumption, perhaps because smokers vary in the degree and depth of smoke inhalation. This study examined the role of smoke inhalation in the development of COPD. Eighty current smokers and 20 lifetime nonsmoking volunteers (aged 35-65 yrs) were recruited. Lung function variables were measured and high-resolution computed tomography (HRCT) scans performed. Smoke inhalation was assessed by CO boost (the increment of expired carbon monoxide 5 min after smoking a cigarette) and serum cotinine. Mean CO boost was 6.3 parts per million (ppm) in smokers with low CO transfer coefficients (KCO) and 2.9 ppm in those with normal KCO (p=0.006); 7.2 ppm in smokers with both HRCT-defined emphysema and a low KCO and 2.6 ppm in those with neither abnormality (p=0.002); 4.5 ppm in smokers with HRCT-defined emphysema alone and 2.8 ppm in those without (p=0.08). Mean serum cotinine was 328 ng x mL(-1) in smokers with chronic productive cough and 243 ng x mL(-1) in those without (p=0.005). Lifetime nonsmokers had normal HRCT scans, lung function and serum cotinine. Emphysema is associated with high alveolar smoke exposure as measured by CO boost. Productive coughing is associated with high nicotine uptake, probably from airway smoke particle deposition.

Isolation and identification of a plasmatocyte-spreading peptide from the hemolymph of the lepidopteran insect Pseudoplusia includens.

Insect blood cells (hemocytes) play an essential role in defense against parasites and other pathogenic organisms that infect insects. A key class of hemocytes involved in insect cellular immunity is plasmatocytes. Here we describe the isolation and identification of a peptide from the moth Pseudoplusia includens that mediates the spreading of plasmatocytes to foreign surfaces. This peptide, designated plasmatocyte-spreading peptide (PSP1), contains 23 amino acid residues in the following sequence: H-ENFNGGCLAGYMRTADGRCKPTF-OH. In vitro assays using the synthetic peptide at concentrations >/=2 nM induced plasmatocytes from P. includens to spread on the surface of culture dishes. Injection of this peptide into P. includens larvae caused a transient depletion of plasmatocytes from circulation. Labeling studies indicated that this peptide induced 75% of plasmatocytes that were double-labeled by the monoclonal antibodies 49G3A3 and 43E9A8 to spread, whereas plasma induced significantly more plasmatocytes to spread. This suggests that only a certain subpopulation of plasmatocytes responds to the peptide and that other peptidyl factors mediate plasmatocyte adhesion responses.

Effect of a screening profile on the diagnosis of nonaccidental burns in children.

STUDY OBJECTIVE: To determine if awareness of factors associated with burn abuse increases recognition and reporting by emergency physicians. DESIGN: The study consisted of a retrospective chart review and a subsequent intervention. SETTING: An urban pediatric emergency department (ED). PARTICIPANTS: All patients with the diagnosis of burn seen in the ED. INTERVENTION: The retrospective chart review (October 1, 1990, to September 30, 1991) determined the number of patients seen in the ED, diagnosed with burns, and reported to the department of social service. We then determined whether or not the department of social service, after completion of their investigation, "verified" that abuse had occurred. In addition, other services provided to the family by the department of social services were determined. The prospective study (April 1, 1992, to March 30, 1993) introduced a checklist of 13 factors associated with abusive burns into the history and physical examination of all burn victims presenting to the ED. Changes in overall referrals to the department of social service as well as in the numbers of cases in which abuse were verified or services offered were then determined. RESULTS: Prior to any intervention, 3% (3/87) of burns presenting to the ED from 1990 to 1991 were reported to the department of social service. This contrasted with 12.1% (26/215) of burns presenting after introduction of the checklist. Burn victims, 1/87 (1%), in the retrospective study and 16/215 (7.4%) burn victims in the prospective study received social service intervention after a report was initiated by the ED staff (P < .002). Burn injuries 1/87 (1%) and 7/215 (3.3%), reported during the two studies were substantiated as abusive by social services. CONCLUSION: We conclude that the use of the checklist increased effective social service referral for burn abuse.

Extracellular GTP causes membrane-potential oscillations through the parallel activation of Mg2+ and Na+ currents in Paramecium tetraurelia.

Paramecium tetraurelia responds to extracellular GTP (>/= 10 nm) with repeated episodes of prolonged backward swimming. These backward swimming events cause repulsion from the stimulus and are the behavioral consequence of an oscillating membrane depolarization. Ion substitution experiments showed that either Mg2+ or Na+ could support these responses in wild-type cells, with increasing concentrations of either cation increasing the extent of backward swimming. Applying GTP to cells under voltage clamp elicited oscillating inward currents with a periodicity similar to that of the membrane-potential and behavioral responses. These currents were also Mg2+- and Na+-dependent, suggesting that GTP acts through Mg2+-specific (IMg) and Na+-specific (INa) conductances that have been described previously in Paramecium. This suggestion is strengthened by the finding that Mg2+ failed to support normal behavioral or electrophysiological responses to GTP in a mutant that specifically lacks IMg ("eccentric"), while Na+ failed to support GTP responses in "fast-2," a mutant that specifically lacks INa. Both mutants responded normally to GTP if the alternative cation was provided. As IMg and INa are both Ca2+-dependent currents, the characteristic GTP behavior could result from oscillations in intracellular Ca2+ concentration. Indeed, applying GTP to cells in the absence of either Mg2+ or Na+ revealed a minor inward current with a periodicity similar to that of the depolarizations. This current persisted when known voltage-dependent Ca2+ currents were blocked pharmacologically or genetically, which implies that it may represent the activation of a novel purinergic-receptor-coupled Ca2+ conductance.

Effect of SERCA pump inhibitors on chemoresponses in Paramecium.

Inhibitors of SERCA (sarcoplasmic/endoplasmic reticulum Ca(2+)-dependent ATPase) calcium pumps were used to investigate the involvement of internal Ca2+ stores in the GTP response in Paramecium. External application of these inhibitors was found to dramatically alter the typical behavioral and electrophysiological responses of Paramecium to extracellular chemical stimulation. In particular, 2,5-di-tert-butylhydroquinone (BHQ) strongly inhibited the backward swimming response of paramecia to externally applied GTP, though it did not inhibit the associated whirling response. BHQ also prolonged the normally brief electro-physiological response of these cells to GTP. BHQ completely blocked the behavioral and electrophysiological responses of Paramecium to extracellular Ba2+, but had no measurable effect on the behavioral or electrophysiological responses of these cells to another depolarizing stimulus, elevated external K+ concentration. These results suggest the involvement of nonciliary Ca2+ ions in the GTP and Ba2+ responses.

External GTP alters the motility and elicits an oscillating membrane depolarization in Paramecium tetraurelia.

Paramecium, a unicellular ciliated protist, alters its motility in response to various stimuli. Externally added GTP transiently induced alternating forward and backward swimming interspersed with whirling at a concentration as low as 0.1 microM. ATP was 1000-fold less active, whereas CTP and UTP produced essentially no response. The response to the nonhydrolyzable GTP analogs guanosine 5'-[gamma-thio]triphosphate and guanosine 5'-[beta, gamma-imido]triphosphate was indistinguishable from that to GTP. This behavioral response was correlated with an unusual transient and oscillating membrane depolarization in both wild-type cells and the mutant pawn B, which is defective in the voltage-dependent Ca2+ current required for action potentials. This is a specific effect of external GTP on the excitability of a eukaryotic cell and, to our knowledge, is the first purinergic effect to be discovered in a microorganism.

An automated assay for quantifying the swimming behavior of Paramecium and its use to study cation responses.

Paramecium tetraurelia is a ciliated protist that alters its swimming behavior in response to various stimuli. Like the sensory responses of many organisms, these responses in Paramecium show adaptation to continued stimulation. For quantitative studies of the initial response to stimulation, and of the time course of adaptation, we have developed a computerized motion analysis assay that can detect deviations from the normal swimming pattern in a population of cells. The motion of an average of ten cells was quantified during periods ranging from 15 to 60 seconds, with a time resolution of 1/15 seconds. During normal forward swimming, the maximum deviation from a straight-line path was less than 17 degrees. Path deviations above this threshold value were defined as changes in swimming direction. The percentage of total path time that cells spent deviating from forward swimming was defined as percent directional changes (PDC). This parameter was used to construct dose-response curves for the behavioral effects of various externally added cations known to induce behavioral changes and also to show the time course of adaptation to a depolarizing K+ stimulus. This assay is a valuable tool for studies of chemoeffectors or mutations that alter the swimming behavior of Paramecium and may also be applicable to other motile organisms.