Rapid ligand fishing for identification of acetylcholinesterase-binding peptides in snake venom reveals new properties of dendrotoxins.

Acetylcholinesterase (AChE) from Electrophorus electricus (eel) was immobilized on the surface of amino-modified paramagnetic beads to serve as a model for the development, validation and application of a new affinity-based ligand-fishing assay for the discovery of bioactive peptides from complex protein mixtures such as venoms. Nano liquid chromatography-mass spectrometry (nanoLC-MS) was used for the analysis of trapped peptides. Using enzyme-functionalized beads, the ligand-fishing assay was evaluated and optimized using a peptide reference mixture composed of one acetylcholinesterase binder (fasciculin-II) and five non-binders (mambalgin-1, angiotensin-II, bradykinin, cardiotoxin and α-bungarotoxin). As proof of concept, snake venom samples spiked with fasciculin-II demonstrated assay selectivity and sensitivity, fishing the peptide binder from complex venom solutions at concentrations as low as 1.0 µg/mL. As negative controls for method validation, venoms of four different snake species, not known to harbor AChE binding peptides, were screened and no AChE binders were detected. The applicability of the ligand fishing assay was subsequently demonstrated with venom from the black mamba, Jameson's mamba and western green mamba (Dendroaspis spp.), which have previously been reported to contain the AChE binding fasciculins. Unknown peptides (i.e. not fasciculins) with affinity to AChE were recovered from all mamba venoms tested. Tryptic digestion followed by nano-LC-MS analysis of the material recovered from black mamba venom identified the peptide with highest AChE-binding affinity as dendrotoxin-I, a pre-synaptic neurotoxin previously not known to interact with AChE. Co-incubation of AChE with various dendrotoxins in vitro revealed reduced inactivation of AChE activity over time, thus demonstrating that these toxins stabilize AChE.

Randomised clinical trial of the effectiveness of base-in prism reading glasses versus placebo reading glasses for symptomatic convergence insufficiency in children.

PURPOSE: To compare base-in prism reading glasses with placebo reading glasses for the treatment of symptomatic convergence insufficiency (CI) in children aged 9 to <18 years. METHODS: In a randomised clinical trial, 72 children aged 9 to <18 years with symptomatic CI were assigned to either base-in prism glasses or placebo reading glasses. Symptom level, measured with a quantitative symptom questionnaire (CI Symptom Survey-V15), was the primary outcome measure. Near point of convergence and positive fusional vergence at near were secondary outcomes. RESULTS: The mean (SD) CI Symptom Survey score decreased (that is, less symptomatic) in both groups (base-in prism glasses from 31.6 (10.4) to 16.5 (9.2); placebo glasses from 28.4 (8.8) to 17.5 (12.3)). The change in the CI Symptom Survey scores (p = 0.33), near point of convergence (p = 0.91), and positive fusional vergence (p = 0.59) were not significantly different between the two groups after 6 weeks of wearing glasses. CONCLUSIONS: Base-in prism reading glasses were found to be no more effective in alleviating symptoms, improving the near point of convergence, or improving positive fusional vergence at near than placebo reading glasses for the treatment of children aged 9 to <18 years with symptomatic CI.

Potential early-life predictors of dietary behaviour in adulthood: a retrospective study.

OBJECTIVE: Unnecessary dietary restraint (ie in the absence of a need to lose weight) and chronic overeating are both very unhealthy activities. As a precursor to a more involved longitudinal study, we sought to identify potential early-life predictors that merit scrutiny in this context. DESIGN: Four retrospective questionnaire studies were conducted (Study 1, N=242; Study 2, N=297; Study 3, N=175; Study 4, N=261). Female participants (18-30 y) completed measures of current dietary restraint and overeating. They also recalled experiences between 5 and 10 years of age. All were staff or students at Loughborough University (UK). RESULTS: After considering obvious sources of systematic bias, we report evidence that (i) dietary restraint is related to memories of maternal weight and dietary behaviour, and (ii) overeating and meal-size selection are both associated with memories of receiving a high-energy diet. CONCLUSION: The role of maternal factors in dietary restraint is consistent with previous research exploring the early onset of this behaviour. However, the relationship between childhood diet and overeating has not been suggested elsewhere. This is particularly important because it suggests a previously unreported correspondence between childhood experience and behaviours associated with obesity in adulthood.

Visual acuity in contact lens wearers.

PURPOSE: The difference between high- and low-contrast visual acuity provides a sensitive indicator of vision loss in ocular disease; however, the effect of refractive error correction on this difference is still debated. METHODS: High- and low-contrast visual acuity was measured in 116 rigid gas permeable contact lens wearers, 51 spectacle wearers, and 50 soft contact lens wearers with habitual and best correction. Twenty-nine of the soft contact lens wearers reported that they wore disposable contact lenses (discarded on a monthly or more frequent basis), whereas the other 21 soft contact lens wearers wore traditional soft contact lenses. RESULTS: Rigid gas permeable contact lens wearers had statistically worse high-contrast habitual visual acuity than spectacle wearers (Tukey-Kramer, p = 0.0075). Traditional soft contact lens wearers had significantly worse low-contrast visual acuity compared with all other groups (Tukey-Kramer, p < 0.02 for each comparison). Traditional soft contact lens wearers had a significantly larger difference between high- and low-contrast visual acuity with best correction compared with rigid gas permeable wearers (Tukey-Kramer, p = 0.0099). CONCLUSIONS: Rigid gas permeable contact lens wearers had statistically worse habitual high-contrast visual acuity compared with spectacle wearers, but no difference was present under best-corrected conditions. We hypothesize that rigid gas permeable contact lens wearers were not wearing their optimal correction habitually. Traditional soft contact lens wearers had significantly worse low-contrast visual acuity. They also had a larger difference between their best-corrected high- and low-contrast visual acuity scores compared with rigid gas permeable contact lens wearers.

Prospective quantification of near work using the experience sampling method.

INTRODUCTION: The assessment of individuals' near work by survey methods is challenging. The feasibility of the Experience Sampling Method to quantify daily visual tasks was evaluated. METHODS: Twenty-one subjects were randomly paged five times per day for 6 days. When paged, the subjects dialed into a telephone survey to report the nature, duration, and working distance of their visual activity at the time of the page. RESULTS: The overall response rate was 81.3% (512/630 pages). The individual response rates varied from 6.7% to 100% (median, 86.7%). Responses were grouped into 11 categories/activities for ease of analysis. Of 506 responses, the most common activity category was "distance tasks," which included driving and walking (N = 92). Other common responses included computer use (N = 68), reading (N = 66), household tasks, e.g., cleaning, cooking, and showering (N = 64), and watching television (N = 61). Activities with a mean distance < or =26 inches (arm length) were combined as near-work responses and accounted for 54.3% (258/475) of all responses. CONCLUSION: A modification of the Experience Sampling Method can be used to obtain a "real-time" sampling of visual activities.

Characterization of ocular surface symptoms from optometric practices in North America.

PURPOSE: This study characterized ocular symptoms typical of dry eye in an unselected optometric clinical population in the United States and Canada. METHODS: Self-administered dry eye questionnaires, one for non-contact lens wearers (dry eye questionnaire) and one for contact lens wearers (contact lens dry eye questionnaire), were completed at six clinical sites in North America. Both questionnaires included categoric scales to measure the prevalence, frequency, diurnal severity, and intrusiveness of nine ocular surface symptoms. The questionnaires also asked how much these ocular symptoms affected daily activities and contained questions about computer use, medications, and allergies. The examining doctors, who were masked to questionnaire responses, recorded a nondirected dry eye diagnosis for each patient, based on their own diagnostic criteria. RESULTS: The dry eye questionnaires were completed by 1,054 patients. The most common ocular symptom was discomfort, with 64% of non--contact lens wearers and 79% of contact lens wearers reporting the symptom at least infrequently. There was a diurnal increase in the intensity of many symptoms, with symptoms such as discomfort, dryness, and visual changes reported to be more intense in the evening. The 22% percent of non-contact lens wearers and 15% of contact lens wearers diagnosed with dry eye (most in the mild to moderate categories) reported symptoms at a greater frequency than those not diagnosed with dry eye. CONCLUSIONS: Our results show that symptoms of ocular irritation and visual disturbances were relatively common in this unselected clinical population. The intensity of many ocular symptoms increased late in the day, which suggested that environmental factors played a role in the etiology of the symptoms.

The performance of the refractive status and vision profile survey in a contact lens clinical trial.

OBJECTIVE: To evaluate the Refractive Status and Vision Profile (RSVP) questionnaire in a contact lens clinical trial and to assess the feasibility of its use in future trials. DESIGN: Randomized, crossover clinical trial and survey. PARTICIPANTS: The RSVP was administered to 50 contact lens-wearing participants recruited from a large contact lens clinic. METHODS: RSVP scores were calculated for subjects at three outcome visits: (1) baseline, (2) after wearing daily disposable contact lenses, and (3) after wearing disposable extended wear contact lenses. One-sample t tests were used to compare baseline survey scores with those previously reported for the instrument. The relation of survey scores within and between subjects was assessed with repeated measures analysis of variance. Statistical power and sample size calculations were performed to determine the number of subjects required in future studies to detect differences in RSVP subscale scores. MAIN OUTCOME MEASURES: Eight subscale scores (concern, driving, expectations, glare, optical problems, physical and social functioning, problems with corrective lenses, and symptoms) and the overall RSVP score were calculated on the basis of guidelines reported for scoring of the instrument. RESULTS: Five of eight mean subscale scores (concern, expectations, driving, optical problems, and problems with corrective lenses) and the overall score were significantly lower than those previously reported. No differences were found in the following subscales after contact lens treatment: concern, expectations, physical and social functioning, driving, optical problems, problems with corrective lenses, or the overall RSVP score. Significant differences were found on the symptoms (P = 0.03) and glare (P = 0.05) subscales; post hoc testing revealed that the significant differences in these scores occurred between baseline and daily disposable lens wear and not between treatment modalities (daily disposable and disposable extended wear). A sample size of 420 would be required to find clinically relevant significant differences (25%) for all subscales in a similar one-sample clinical trial. A more restrictive difference (10%) would require more than 1100 subjects for four of the nine subscales. CONCLUSIONS: The RSVP questionnaire may not be the appropriate quality-of-life instrument for use in a contact lens clinical trial. The instrument seems to lack sensitivity and discriminative validity in evaluating contact lens treatments.

Aerobic exercise: effects on parameters related to fatigue, dyspnea, weight and body composition in HIV-infected adults.

OBJECTIVES: The purpose of the study was to examine the effects of aerobic exercise on physiological fatigue (time on treadmill), dyspnea [rate of perceived exertion (RPE) and forced expiratory volume at 1 s (FEV1)], weight, and body composition in HIV-1-infected adults (200-499 x 106 CD4+ cells/l). DESIGN: The study was a randomized, wait-listed, controlled clinical trial of aerobic exercise in HIV-1-infected adults on signs and symptoms associated with HIV-1 infection or its treatment. METHODS: Sixty subjects were recruited and randomized to two groups. Experimental subjects completed a 12-week supervised exercise program. Control subjects continued usual activity from baseline to week 12 and were then were enrolled in the exercise program. RESULTS: At baseline, the groups were similar in age, weight, body mass index [mean body mass index (BMI) > 27], time since diagnosis, number of symptoms, CD4+ cell count, and number on protease inhibitor therapy (n = 7). Despite disproportionate attrition from the exercise group (38%), exercise subjects were able to remain on the treadmill longer, lost weight, decreased BMI, subcutaneous fat, and abdominal girth when compared to controls. The improvement in weight and body composition occurred without a decrease in kilocalories consumed. Exercise did not seem to have an effect on RPE, a surrogate for dyspnea, and FEV1. There was no significant difference in either the change in CD4+ cell count, percentage or copies of plasma HIV-1 RNA between groups. CONCLUSIONS: We conclude that supervised aerobic exercise training safely decreases fatigue, weight, BMI, subcutaneous fat and abdominal girth (central fat) in HIV-1-infected individuals. It did not appear to have an effect on dyspnea.

Daily disposable vs. disposable extended wear: a contact lens clinical trial.

BACKGROUND: The purpose of this work was to compare traditional standards of contact lens success and patient-reported preferences in the daily-disposable and disposable extended-wear contact lens modalities. METHODS: This study was a randomized, cross-over contact lens clinical trial involving 50 patients. After the baseline examination, two outcome examinations were performed including the self-administration of the Refractive Status and Vision Profile (RSVP) survey, an additional survey, and masked visual acuity and slit-lamp assessments. RESULTS: No differences were noted on the RSVP when comparing treatment modalities. Patients were considered equally successful in terms of wearing time, overall comfort, visual acuity, and ocular health criteria. In terms of patient preferences, a significant number of patients preferred the disposable extended-wear modality over the daily-disposable modality (chi2(1) = 4.08, p = 0.04). Patients preferred disposable extended-wear over daily-disposables due to convenience (odds ratio = 30.33). CONCLUSIONS: Disposable extended-wear represents a convenient contact lens option for contact lens patients.

Agricultural hazard data from a population-based survey of cash grain farms: Ohio observations.

In response to congressional concerns, the National Institute for Occupational Safety and Health (NIOSH) initiated a multistate agricultural surveillance effort in 1990. The Farm Family Health and Hazard Surveillance (FFHHS) program involved separate population-based surveillance efforts by six state agencies or universities which gathered health and hazard data on farm operators and farm families. The results of the Ohio program are presented as an example of the data collection capabilities developed during the course of this project, which include the application of these data in documenting the prevalence of specific agricultural occupational hazards as well as the current attitudes of agricultural operators toward control and elimination of safety and health hazards. Specifically, three operationally defined areas of hazard audit (Structures, Landscape, and Mobile Equipment) are examined for the prevalence of such safety hazards as potential electrical shock, slippery or badly maintained walkways, inadequate chemical and fuel storage, and missing farm equipment moving-part guards. Questionnaire survey response examples are presented as an indication of farm operator attitudes toward safety and health training, on-site professional service access, and use of personal protective equipment. Current plans for data use and distribution, and the potential applications of the data as an occupational safety and health tool are also discussed.

A cross-sectional case control study of work-related injuries among Ohio farmers.

The agricultural industry has consistently been ranked among the most hazardous in the U.S. To date, few analytic studies of occupational injury among farm operators and workers have been conducted. A case control study was undertaken to investigate risk factors for agricultural work-related injury among Ohio farm operators. Cases were selected from among 1,793 respondents to a questionnaire administered during the first phase of the NIOSH-sponsored Ohio Farm Family Health and Hazard Study (OFFHHS). Analysis consisted of description of the injury experience of the sample as a whole, followed by logistic estimation of prevalence odds ratios (pORs) measuring the effect of potential risk factors on injury risk. The case series consisted of 90 white male principal operators (POs) injured doing farm work in the 12 months prior to questionnaire completion. Controls consisted of 1,475 white male POs who reported no injuries. The overall rate of injury was 5 per 100 person-years. The most notable result is the relationship between self-reported neurotoxic symptoms and injury, suggesting those with more reported symptoms were at greater risk of injury. The crude OR, when compared to the reference score of < or = 27, increased from 1.74 (95% CI = 0.60-5.09) in the 28-30 category, to 1.89 (95% CI = 0.71-5.03) in the 31-35 category, to 2.96 (95% CI = 1.10-7.96) in the highest category of test score. The P value for trend was 0.0218. These associations largely persisted after controlling for potential confounders with multiple logistic regression. Risk was inversely related to age. The results show marked increases in risk of injury associated with farmers younger than 30 and increased severity of self-reported neurological symptoms, controlling for potential confounding.

Hearts and minds: suicide among United States combat troops in Vietnam, 1957-1973.

The literature on suicides among military personnel in a combat zone remains anecdotal. Although one finds literary and journalistic accounts of the problem, it has not been systematically analyzed. This paper will examine suicides among American combat troops during their tour of duty in Vietnam. Utilizing statistical data from the Southeast Asia Combat Area Casualties Database (SACACD), the authors will survey its epidemiology among U.S. ground troops in Vietnam from 1957 to 1973. The results suggest that certain types of combat troops were significantly more likely than others to commit suicide. These findings not only provide important predictors for military health professionals in the assessment of suicide risk, they also raise disturbing questions about the nature of organized armed conflict.

Characteristics of general dentists participating in home study courses.

With an increasing number of states requiring continuing dental education (CDE) for license renewal, dentists are opting for different ways of earning these credit hours beyond the traditional didactic presentation. One alternative is a home study correspondence course. Little is known about the type of dentists who participate in these home study courses. This study examines characteristics of 507 general dentists in Ohio who were required to submit information concerning their CDE courses and credit hours during the biennium, 1992-93. Twenty-five percent of the general dentists took at least one home study course, and approximately five percent of those dentists participating in any home study earned all their credit hours this way. A logistic regression model indicated that home study users are less likely to be ADA members and less likely to leave the state for any CDE. This study suggests that the current methods of home study courses may provide continuing education opportunities for dentists who otherwise might not be reached by more traditional ways of CDE.

Medical students' and private family physicians' perceptions of family practice.

BACKGROUND: Many studies have attempted to determine what factors influence medical students' career selections. This study determined students' perceptions of family practice, examined what variables influenced these perceptions, and measured whether medical students' perceptions were similar to or different from those of practicing family physicians. METHODS: The two populations studied were students sampled at an Ohio medical school over the first 3 years of their training and a random sample of Ohio family physicians. Each subject was asked to complete a questionnaire that asked about perceptions of family practice and demographic information. RESULTS: A total of 719 (69%) students and 295 (59%) family physicians responded to the survey. Sixty-seven percent of the physician responders were actively involved in medical student teaching. More than 94% of the students had exposure to family physicians during their preclinical education. Students' perceptions were different than physicians' perceptions about lifestyle issues, patient care, and practice characteristics; over time, these approached the physicians' perceptions. However, the perceptions of family physicians and students about professional issues were similar. DISCUSSION: Medical students and family physicians have different perceptions about family practice. Students' perceptions become similar to physicians' perceptions as they progress through the educational system, while, at the same time, their interest in family practice declines.

Sequencing, cloning, and expression of human red cell-type acid phosphatase, a cytoplasmic phosphotyrosyl protein phosphatase.

Low molecular weight phosphotyrosyl protein phosphatases of human placenta and human red cell were purified and sequenced by a combination of Edman degradation and tandem mass spectrometry. Screening of a human placental lambda gt11 cDNA library yielded overlapping cDNA clones coding for two distinct human cytoplasmic low molecular weight phosphotyrosyl protein phosphatases (HCPTPs). The two longest clones, designated HCPTP1-1 and HCPTP2-1, were found to have identical nucleotide sequences, with the exception of a 108-base pair segment in the middle of the open reading frame. Polymerase chain reaction studies with human genomic DNA suggest that the difference between HCPTP1-1 and HCPTP2-1 does not result from alternative RNA splicing. Studies with a human chromosome 2-specific library confirmed that these sequences are located on chromosome 2, which is known to be the location of red cell acid phosphatase locus ACP1. The coding sequences of HCPTP1-1 and HCPTP2-1 were placed downstream from a bacteriophage T7 promoter and the proteins were expressed in Escherichia coli. The resulting recombinant enzymes (designated HCPTP-A and HCPTP-B, respectively) showed molecular weights of 18,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and both of them exhibited immunoreactivity with antisera raised against authentic human placental and bovine heart enzymes. The expressed proteins were highly active towards the phosphatase substrates p-nitrophenyl phosphate, beta-naphthyl phosphate, and O-phospho-L-tyrosine, but not alpha-naphthyl phosphate, threonine phosphate, or O-phospho-L-serine. HCPTP-A and -B possessed effectively identical amino acid compositions, immunoreactivities, inhibition by formaldehyde, and kinetic properties when compared with two human red cell acid phosphatase isoenzymes. It is concluded that HCPTP-A and -B are the fast and slow forms of red cell acid phosphatase, respectively, and that this enzyme is not unique to the red cell but is instead expressed in all human tissues.

Development of a medical fiber-optic oxygen sensor based on optical absorption change.

A new fiber-optic oxygen sensor has been developed for use in medical applications. The sensor's viologen indicator becomes strongly absorbent after brief UV stimulation, and then returns to the transparent state. The rate of indicator return to transparency is proportional to the local oxygen concentration. Indicator absorbance is monitored with a red LED and receiving photodiode, and absorbance data are processed by a dedicated cpu. The solid-state sensor system has performance comparable to existing oxygen measurement techniques, and may be applicable for both in vitro and in vivo oxygen measurements.

Development of medical pressure and temperature sensors employing optical spectrum modulation.

Fiber optic Fabry-Perot sensors have been developed whose optical reflectance varies with optical cavity depth (pressure) or with change in a material's refractive index (temperature). These sensors employ a unique combination of features: they are interrogated by an LED; they are designed to operate within a single reflectance cycle; and their returned light is analyzed by a dichroic ratio technique. The sensors use a step index glass fiber and are relatively insensitive to absolute light levels and fiber bending. They have an expanded linear operating range and can be built for low cost disposable applications. Sensor performance meets or exceeds established medical requirements.