An outbreak of Escherichia coli O157:H7 infections following a dairy education school field trip in Washington state, 2015.

On 27 April 2015, Washington health authorities identified Escherichia coli O157:H7 infections associated with dairy education school field trips held in a barn 20-24 April. Investigation objectives were to determine the magnitude of the outbreak, identify the source of infection, prevent secondary illness transmission and develop recommendations to prevent future outbreaks. Case-finding, hypothesis generating interviews, environmental site visits and a case-control study were conducted. Parents and children were interviewed regarding event activities. Odds ratios (OR) and 95% confidence intervals (CI) were computed. Environmental testing was conducted in the barn; isolates were compared to patient isolates using pulsed-field gel electrophoresis (PFGE). Sixty people were ill, 11 (18%) were hospitalised and six (10%) developed haemolytic uremic syndrome. Ill people ranged in age from <1 year to 47 years (median: 7), and 20 (33%) were female. Twenty-seven case-patients and 88 controls were enrolled in the case-control study. Among first-grade students, handwashing (i.e. soap and water, or hand sanitiser) before lunch was protective (adjusted OR 0.13; 95% CI 0.02-0.88, P = 0.04). Barn samples yielded E. coli O157:H7 with PFGE patterns indistinguishable from patient isolates. This investigation provided epidemiological, laboratory and environmental evidence for a large outbreak of E. coli O157:H7 infections from exposure to a contaminated barn. The investigation highlights the often overlooked risk of infection through exposure to animal environments as well as the importance of handwashing for disease prevention. Increased education and encouragement of infection prevention measures, such as handwashing, can prevent illness.

Spectral behavior of a terahertz quantum-cascade laser.

In this paper, the spectral behavior of two terahertz (THz) quantum cascade lasers (QCLs) operating both pulsed and cw is characterized using a heterodyne technique. Both lasers emitting around 2.5 THz are combined onto a whisker contact Schottky diode mixer mounted in a corner cube reflector. The resulting difference frequency beatnote is recorded in both the time and frequency domain. From the frequency domain data, we measure the effective laser linewidth and the tuning rates as a function of both temperature and injection current and show that the current tuning behavior cannot be explained by temperature tuning mechanisms alone. From the time domain data, we characterize the intrapulse frequency tuning behavior, which limits the effective linewidth to approximately 5 MHz.

Potential rabies exposures in a Virginia county.

OBJECTIVE: Although records of animal bites and scratches are kept at most local health departments, little is known about the epidemiology and characteristics of these potential rabies exposures on a local level. Bite and scratch records for a four-and-a-half-year period from Montgomery County, Virginia, were examined in order to identify preventable trends. METHODS: The author retrospectively reviewed animal bite and scratch records from the Montgomery County Health Department dating from January 1992 through July 1996. RESULTS: Cat bites or scratches involved stray or feral animals more than eight times as often as dog bites or scratches. Cats were involved in the majority of incidents in which rabies postexposure prophylaxis (PEP) was recommended. Overall, PEP was recommended following 5.9% of reported incidents. The records also indicated that 65% of owned cats were unvaccinated at the time of the incident, while only 28% of owned dogs were unvaccinated. Children under the age of 18 were significantly more likely to be involved in a potential exposure than adults. CONCLUSIONS: Potential exposures should be analyzed periodically by local health departments. Suggestions for minimizing the number of potential rabies exposures in Montgomery County based on the results of the study reported here include: reducing the stray and feral cat population, targeting educational programs to children, and encouraging owners to vaccinate their pets.

Anabolic implant effects on steer performance, carcass traits, subprimal yields, and longissimus muscle properties.

Crossbred steers (n = 140; 353 kg) were implanted as follows: (C) control, no implant; (S) Synovex-S (20 mg estradiol benzoate + 200 mg progesterone); (R) Revalor (20 mg estradiol + 140 mg trenbolone acetate [TBA]; international dosage); (ST) S + finaplix-S (140 mg TBA); (STT) S + finaplix-S with finaplix-S reimplanted on d 58. Steers were harvested after 119 to 126 d on feed. Left sides of 40 carcasses were fabricated into boneless subprimals for two s.c. fat levels: 2.5 and .64 cm. Steers administered an estrogen (estradiol benzoate or estradiol) plus TBA gained more rapidly (P < .05) than C or S steers. Feed efficiency was improved (P < .05) with an estrogen plus TBA. No differences (P > .05) were noted among treatments for carcass s.c. fat thickness, percentage internal fat, or lean color. Carcasses from steers receiving TBA had larger (P < .05) longissimus areas and tended to have lower (P < .10) marbling scores and yield grades than C or S steers. Steers implanted with R had a lower (P < .05) percentage of U. S. Choice carcasses (51.8%) than C, S, and ST steers (82 to 86%). Shear force values for implanted steers tended to be higher (P < .10) than for controls. Implants increased (P < .05) subprimal and total side lean yields (.64 cm) compared to controls; the largest increases of 2.3 and 2.8%, respectively, occurred in steers receiving TBA plus an estrogen. Estrogen plus TBA exhibited favorable effects on gain, efficiency, and composition; however, the single estradiol plus TBA implant (R) decreased quality grade.

Results from the low level mercury sorbent test at the Oak Ridge Y-12 Plant in Tennessee.

A mercury sorbent test was performed near the headwaters of the Upper East Fork Poplar Creek at the Oak Ridge Y-12 Plant in Tennessee. The sorbents SIR-200 (ResinTech), Keyle:X (SolmeteX), and GT-73 (Rohm and Haas) were the best materials tested for low level mercury removal. Each of these sorbents has a thiol-based active site. None of the tested sorbents reduced the mercury concentration to less than the existing 12 ng/l NPDES limit. For this small scale test, SIR-200, Keyle:X, and GT-73 reduced the mercury concentration to less than 51 ng/l, which is a regulatory treatment goal. The other sorbents tested, including granular activated carbon (Filtrasorb 300), did not reduce the mercury concentration below 51 ng/l at any tested flow up to 5 bed volumes per minute. Because of the cost and large volume of sorbent, a wastewater treatment plant for this stream would be prohibitively expensive to construct and maintain.

Large-scale human exposures to rabid or presumed rabid animals in the United States: 22 cases (1990-1996).

OBJECTIVE: To identify common elements of large-scale human exposures to rabid or presumed rabid animals in the United States from 1990 to 1996. DESIGN: Retrospective study. PROCEDURE: Health departments in 50 states and the District of Columbia were contacted regarding episodes of large-scale human exposures to rabid animals occurring between 1990 and 1996. A large-scale exposure was defined as administration of postexposure prophylaxis (PEP) to 25 or more people after an exposure to a rabid or presumed rabid animal or littermates. Incident-specific information was obtained through questionnaires sent to states reporting episodes. Data are reported as medians. RESULTS: Fifteen of 51 (29.4%) health departments reported 22 episodes; 72.7% involved companion animals or livestock. Twenty-six animals were involved in these 22 episodes, including 10 (38.5%) dogs, 4 (15.4%) livestock, 4 (15.4%) raccoons, 3 (11.5%) cats, 3 (11.5%) bats, and 2 (7.7%) ferrets. Schools (36.4%) and public places (22.7%) were the most common settings for exposures. Reportedly, 1,908 people received PEP. The cost for 10 episodes was $61,547/episode (range, $14,199 to $1,500,000). An episode-specific written algorithm for recommending PEP had been developed for use in only 4 (18.2%) episodes. CLINICAL IMPLICATIONS: Large-scale exposures most commonly involved a single companion animal. Exposures attributable to improper handling of wildlife and unrestricted access of animals in schools and public areas can be potentially remedied by targeted education. Use of an episode-specific algorithm to determine need for PEP may also reduce the number of unnecessary treatments.

Anterior ankle arthroplasty.

Osteophytic proliferation at the anterior ankle joint level occurs secondary to repeated direct trauma to the talus and tibia during extreme dorsiflexion of the ankle. This syndrome occurs frequently, especially in athletes. As the exostosis increases in size, ankle joint motion decreases. With increased activity, patients will complain of pain at the anterior aspect of the ankle joint, secondary to the osseous impingement occurring at the tibiotalar joint. If surgical resection is planned, the following should be considered: (1) Proper planning of the incision should give optimal exposure to the tibiotalar joint. (2) Meticulous dissection should be used to identify and carefully retract the superficial and deep neurovascular structures. (3) Adequate repair of the inferior and superior bands of the extensor retinaculum is critical in order to prevent postoperative bowstringing of the anterior tendons. (4) A postoperative course of 3 weeks nonweight bearing is required to help avoid hypertrophic scar formation and allow adequate healing of the extensor retinaculum. (5) Passive range of motion may be started after suture removal at 10 to 14 days. (6) Active range of motion should begin with the initiation of weight bearing at the start of the fourth week. Rewarding results from anterior ankle arthroplasty resection have been seen in those patients presenting with the classical symptoms, as discussed previously, and radiographic evidence of exostosis formation and impingement of the anterior tibiotalar joint.

CO2 laser-based dispersion interferometer utilizing orientation-patterned gallium arsenide for plasma density measurements.

A dispersion interferometer based on the second-harmonic generation of a carbon dioxide laser in orientation-patterned gallium arsenide has been developed for measuring electron density in plasmas. The interferometer includes two nonlinear optical crystals placed on opposite sides of the plasma. This instrument has been used to measure electron line densities in a pulsed radio-frequency generated argon plasma. A simple phase-extraction technique based on combining measurements from two successive pulses of the plasma has been used. The noise-equivalent line density was measured to be 1.7 × 10(17) m(-2) in a detection bandwidth of 950 kHz. One of the orientation-patterned crystals produced 13 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 13 W of peak power. Two crystals arranged sequentially produced 58 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 37 W of peak power.

The action of valinomycin in uncoupling corn mitochondria.

Valinomycin in the presence of potassium is a potent uncoupler of corn (Zea mays L.) mitochondria, eliminating respiratory control. Valinomycin produces higher steady state potassium phosphate swelling which can be reversed to give active shrinkage if mersalyl is added to block the Pi(-)/OH(-) antiporter. Respiration declines concurrently. Uncouplers accelerate the shrinkage and restore the respiration. The same results can be obtained with sodium phosphate if gramicidin D is substituted as ionophore.It is concluded that valinomycin uncoupling is the result of cyclic salt transport, with influx pumping of potassium phosphate via the Pi(-)/OH(-) antiporter and efflux pumping via a K(+)/H(+) antiporter. The result is a higher level of steady state swelling, rapid turnover of the proton gradient, and uncoupled respiration rates. The level of steady state swelling can be manipulated by varying the valinomycin or K(+) concentrations, with high concentrations favoring activation of the efflux pump.A mosaic membrane model with high resistance for proton and monovalent cation penetration to the cation(+)/H(+) antiporter is used to explain the results.

Forgetting of Acquisition and Extinction in an Invertebrate.

Two experiments with isopods, Armadillidium vulgare, were reported. In Experiment I, two groups of five Ss each learned to run a T maze to escape light and heat. Both original learning (OL), and relearning (RL) the next day, were to a criterion 9/10 correct. Between OL and RL one group was immobilized (I), and the other group was given the opportunity for activity (A). The I treatment resulted in greater savings on RL than did the A treatment, and it was thus concluded that A is a retroaction treatment. Experiment II was like I except that all Ss were extinguished immediately following OL, and then given either A or I until RL. In this experiment, the A treatment led to no savings, but the I treatment produced negative savings (more trials on RL relative to OL). It was concluded that the A treatment had retroactively interfered with extinction, and this result was discussed as analogous to differential spontaneous recovery in favor of the A group. It was concluded that Liberman's (4, 5) theory (that spontaneous recovery is due to the forgetting of extinction) is supported by the result of Experiment II.

Anterior ankle arthroplasty: a retrospective study.

A retrospective analysis of surgical resection of symptomatic tibiotalar impingement exostosis was performed at the Podiatry Hospital of Pittsburgh. Thirty-four patients with a postoperative follow-up ranging from 17 to 97 months, with an average of 36 months were studied. The study has demonstrated an 88% satisfaction rate with patients who sustained anterior ankle arthroplasty at The Podiatry Hospital of Pittsburgh.

Keller arthroplasty with autogenous bone graft in the treatment of hallux limitus.

This manuscript presents an alternative surgical procedure in the treatment of hallux limitus. A description of a modified Keller arthroplasty in which the removed base of the proximal phalanx is remodeled and replaced in the first metatarsophalangeal joint is presented. An in-depth review of the procedure has been performed in 220 cases over the last 4 years at the Podiatry Hospital of Pittsburgh, and a study of 25 patients with over 15 months of follow-up is included. Early range of motion, preservation of articular surfaces, no implanted materials, and the option of multiple revisional procedures are the advantages of this procedure.

Intestinal disaccharidase and alkaline phosphatase activity in giardiasis.

We report results on determinations of small intestinal brush-border enzyme activities in 22 children (aged 11 months to 14 years) with giardiasis. In particular, activities of disaccharidases (lactase, sucrase, maltase) and of alkaline phosphatase were investigated. Forty-one percent of the patients, irrespective of age, had a demonstrable depression of disaccharidase activities, usually in a combination involving two or more enzymes. A depression of intestinal alkaline phosphatase activity was present in 33% of patients, and only in those who demonstrated disaccharidase deficiencies. Mild villus atrophy was present in two mucosal specimens, whereas all others showed normal villus morphology by light microscopy. The results obtained in this study suggest that giardiasis in otherwise healthy children does not cause marked structural damage to the small bowel mucosa, as seen by the light microscope. However, some form of damage to the brush border does occur frequently, as evidenced by a depression of brush-border enzymes. This damage most likely contributes to the diarrhea and also to the carbohydrate intolerance in these patients.

The effects of role-playing high gender identification on the California Psychological Inventory.

This study of the California Psychological Inventory (CPI) demonstrates that subjects can alter significantly their CPI profiles through role-playing high gender identification, i.e., males attempt to appear more masculine and women attempt to appear more feminine. The majority of these subjects did so without being detected by the validity scales designed to detect faking good or bad. Thirty-two volunteers, 16 male and 16 female, participated as subjects. A 2 X 2 ANOVA (subject gender by instructions to role-play vs. standard instructions) design was used. A significant main effect (p less than .01) for instructions was found on 14 of 18 scales and a significant interaction effect (p less than .01) on 4 of 18 scales. The profiles from the role-playing subjects indicate that the stereotypes of both genders, as seen by these subjects, are maladaptive. Implications for practical application of these findings are discussed.

Calcium handling by sarcoplasmic reticulum of neonatal swine cardiac myocytes.

In recent years, because of similarities to human infants, neonatal piglets have increasingly become the model of choice for studying neonatal heart function. However, the cardiac sarcoplasmic reticulum (SR) has not been thoroughly characterized in this species. Accordingly, Ca2+ pump kinetics, efflux channel characteristics, Ca2+ transients, and contractile movements were examined in isolated newborn piglet cardiac ventricular myocytes. Maximum uptake rate (Vmax) and concentration required to produce a half-maximal effect (K0.5) for oxalate-supported, ATP-dependent 45Ca2+ uptake by the SR of digitonin-lysed myocytes were 285 +/- 17 nmol 45Ca2+.min-1.mg-1 and 0.69 +/- 0.07 microM, respectively. In the absence of phospholamban phosphorylation, Vmax was reduced to 195 +/- 26 nmol 45Ca2+.min-1.mg-1 (P < 0.05 vs. control) and K0.5 increased to 1.28 +/- 0.13 microM (P < 0.05 vs. control). [3H]ryanodine binding studies yielded a maximum binding capacity of 181 +/- 12 fmol/mg and a dissociation constant of 1.7 +/- 0.2 nM. Raising extracellular Ca2+ (0.5-5 mM) increased peak amplitude and decreased the duration of electrically stimulated fura 2 Ca2+ transients and recordings of cell length changes. Both ryanodine and 2,5-di-tert-butylhydroquinone, an inhibitor of SR calcium adenosinetriphosphatase, completely abolished Ca2+ transients in piglet myocytes. These studies indicate that the SR has a significant role in excitation-contraction coupling in neonatal piglet myocytes.