Electron backscatter diffraction as a domain analysis technique in BiFeO(3)-PbTiO(3) single crystals.

xBiFeO(3)-(1-x)PbTiO(3) single crystals were grown via a flux method for a range of compositions. Presented here is a study of the domain configuration in the 0.5BiFeO(3)-0.5PbTiO(3) composition using electron backscatter diffraction to demonstrate the ability of the technique to map ferroelastic domain structures at the micron and submicron scale. The micron-scale domains exhibit an angle of approximately 85 degrees between each variant, indicative of a ferroelastic domain wall in a tetragonal system with a spontaneous strain, c/a - 1 of 0.10, in excellent agreement with the lattice parameters derived from x-ray diffraction. Contrast seen in forescatter images is attributed to variations in the direction of the electrical polarization vector, providing images of ferroelectric domain patterns.

Reducing methicillin-resistant Staphylococcus aureus (MRSA) patient exposure by infection control measures.

INTRODUCTION: To assess the effectiveness of infection control measures (pre-admission screening and patient segregation) on reducing in-patient exposure to methicillin-resistant Staphylococcus aureus (MRSA). PATIENTS AND METHODS: A prospective case-control study in a district general hospital. All admissions to 3 wards over an 83-month period from September 1995 to July 2002 inclusive (a total of approximately 34,000 patients). Outcome measures were a statistical analysis of the difference in numbers of new cases of MRSA colonisation or infection between the 3 wards. RESULTS: There was a statistical significance in incidence of new MRSA cases between the ward with active infection control measures in place and the control wards. CONCLUSIONS: The described infection control measures reduced the exposure of patients to MRSA. This reduces the risk of MRSA infection, which is of importance in orthopaedics, and has further benefits that may also be applied in other surgical specialties.

Delivery of pediatric after-hours care by call centers: a multicenter study of parental perceptions and compliance.

BACKGROUND: Despite the rapid growth of centralized call centers to provide after-hours triage to patients of multiple providers, little is known about the perceptions of parents regarding this type of care and their compliance with triage disposition recommendations. DESIGN/METHODS: From August through September 1999, randomized samples of after-hours calls were selected each day from computerized records at 4 pediatric call centers at 1) Children's Hospital, Denver, Colorado; 2) Children's Hospital of Philadelphia, Philadelphia, Pennsylvania; 3) Rainbow Babies and Children's Hospital, Cleveland, Ohio; and 4) All Children's Hospital, St Petersburg, Florida. All participating call centers use the same triage software. Calls were randomly selected to yield at least 250 callers with nonurgent dispositions and 100 with urgent dispositions from each site. Telephone surveys to callers were conducted by an external survey unit 3 to 7 days after the call to the call center. RESULTS: Surveys were completed for 70.5% of those sampled (N = 1561). Parents indicated they were very satisfied or satisfied with aspects of care received from 92.6% (waiting time) to 99.4% (nurse courteousness) of the time. Satisfaction did not differ by site or by recommended disposition of the index call. Most parents (65.2%) reported no preference about speaking with a physician or nonphysician for after-hours care, whereas 27.7% preferred to speak with a physician. Usually speaking with a physician during office hours (odds ratio [OR]: 1.48), feeling it was important that provider knows child's medical history (OR: 3.47), and respondent having an educational level of college graduate or higher (OR: 1.30) were significant predictors of preferring to speak with a physician. Of the 37.0% (N = 723) of parents who reported any change in their relationship with their primary provider as a result of the after-hours call center, 95.7% (N = 691) assessed the change to be positive. Reported compliance with the call center disposition recommendation was 83.3% for urgent referral, 41.0% for next day, 4.5% for visit at a later time, and 78.2% for home care. The major reason given by parents for noncompliance was reporting that they heard a different disposition (76.9% for urgent to 100% for visit at a later time). CONCLUSIONS: Parental satisfaction with pediatric call centers was uniformly high in 4 different geographic locations, and almost all parents who reported any effect on their relationship with their primary provider assessed it as positive. Compliance with recommendations for urgent evaluation or home care was relatively high but for intermediary dispositions was low. In most cases in which noncompliance occurred, parents reported hearing a different disposition. Additional study is needed to clarify whether noncompliance, especially in cases in which an urgent recommendations was made, is attributable to poor nurse communication of the recommended disposition, parental misinterpretation, or parental difference of opinion.

Tests of Buffergel for contraception and prevention of sexually transmitted diseases in animal models.

BACKGROUND: BufferGel is a novel spermicidal and microbicidal gel formulated to maintain the natural protective acidity of the vagina by acidifying semen, which otherwise alkalinizes the vagina. GOAL: To test the efficacy of BufferGel for preventing sexually transmitted infections and pregnancy in animal models. STUDY DESIGN: Animals were challenged with pathogens or sperm after pretreatment with both test and control agents, or after no pretreatment, then evaluated for infection or pregnancy using standard methods. RESULTS: BufferGel provided significant contraceptive efficacy in the rabbit, and significant protection against vaginal and rectal transmission of herpes simplex virus type 2 (HSV-2) in the mouse, vaginal transmission of Chlamydia trachomatis in the mouse, and skin transmission of cottontail rabbit papillomavirus in the rabbit. It did not protect against vaginal transmission of Neisseria gonorrhoeae in the mouse. CONCLUSIONS: The protective efficacy of BufferGel in five of the six animal models suggests that this microbicide warrants clinical evaluation for both contraception and disease prevention.

The effect of culture growth phase on induction of the heat shock response in Yersinia enterocolitica and Listeria monocytogenes.

The effect of culture growth phase on induction of the heat shock response in Yersinia enterocolitica and Listeria monocytogenes, was examined. Exponential or stationary preconditioned cultures were heat shocked and survivor numbers estimated using selective and overlay/resuscitation recovery techniques. The results indicate that prior heat shock induced increased heat resistance in both micro-organisms to higher heat treatments. Heat-shocked cells of each micro-organism were able to survive much longer than non-heat-shocked cells when heated at 55 degrees C. The size of the change in heat resistance between heat-shocked and non-heat-shocked cells was greatest for exponential cultures (X:X). Results indicate that the overall relative thermal resistance of each pathogen was dependent on cell growth phase. Stationary cultures (S:S) were significantly (P < 0.01) more thermotolerant than exponential cultures (X:X) under identical processing conditions. Under most conditions, the use of an overlay/resuscitation recovery medium resulted in higher D-values (P < 0.05) compared with a selective recovery medium.

Reducing after-hours referrals by an after-hours call center with second-level physician triage.

OBJECTIVES: One-third of practices signing-out to The Children's Hospital Call Center in Denver, Colorado, choose to do second-level physician (SLP) triage for calls judged by the Center to require after-hours referral (AHR). We examined: 1) the effect of SLP triage on the rate of AHRs and 2) reasons for physicians' decisions. DESIGN: From January 1998 to August 1998 all calls from patients using a 5-member suburban pediatric practice judged by the Call Center to require AHR were referred to the practice's on-call physician who did SLP triage and completed a questionnaire. RESULTS: There were 955 eligible calls, 22% (N = 216) of which were initially given an urgent disposition by Call Center nurses. Physician questionnaires were completed for 97% (N = 209). Of patients initially triaged for AHR, 49% (N = 103) were subsequently given an AHR, 17% (N = 35) a next day office referral, and 34% (N = 71) home care and advice. Reasons for not urgently referring included the following: 1) medical problem didn't require urgent evaluation (95%, N = 99); 2) change in the patient's condition; (40% N = 43); 3) prior knowledge of family's ability to evaluate and care for the patient (40%, N = 43); and 4) knowledge of the patient's medical history (18%, N = 19). After SLP triage the overall urgent referral rate was 11%. CONCLUSIONS: Signing out to a Call Center decreased physicians' after-hours calls by 77% and SLP triage halved the number of urgent after-hours referrals.

The effect of temperature and selective agents on the growth of Yersinia enterocolitica serotype O:3 in pure culture.

This study examined the individual and combined effects of the selective agents normally present in Yersinia-selective agar (i.e. cefsulodin, irgasan and novobiocin) on the growth kinetics of plasmid-bearing (P+) and plasmid-cured (P-) Yersinia enterocolitica serotype O:3 at 25 and 37 degrees C. Growth studies were carried out in pure culture, and the data obtained were subjected to linear regression analysis to determine lag phase duration(s) and growth rates of the examined strains. In general, the presence of selective agents increased the duration of the lag phase at 37 degrees C, with longer lag phases noted in all cases in which two or more selective agents were present. Growth rates in CIN broth base (CIN NA) and CIN NA plus commercial supplement (SR 109) (CIN) were faster at 37 than 25 degrees C, but in some cultures of incomplete CIN NA broth with less than three supplements added, growth tended to be faster at 25 than 37 degrees C. Generally, plasmid-bearing strains grew slower than plasmid-cured strains in most media at 37 degrees C due to virulence plasmid expression retarding growth. In some instances at 37 degrees C, it was observed that the growth rates of both plasmid-bearing and plasmid-cured strains were comparable, indicating the influence of added selective agent/s negating any effects associated with virulence plasmid expression. The effects of selective agents, incubation temperature and virulence plasmid carriage on the growth kinetics of Y. enterocolitica are discussed.

Inward rectifier potassium conductance regulates membrane potential of canine colonic smooth muscle.

1. The membrane potential of gastrointestinal smooth muscles determines the open probability of ion channels involved in rhythmic electrical activity. The role of Ba2+-sensitive K+ conductances in the maintenance of membrane potential was examined in canine proximal colon circular muscle. 2. Application of Ba2+ (1-100 microM) to strips of tunica muscularis produced depolarization of cells along the submucosal surface of the circular muscle layer. Significantly higher concentrations of Ba2+ were needed to depolarize preparations from which the submucosal and myenteric pacemaker regions were removed. 3. Elevation of extracellular [K+]o (from 5.9 to 12 mM) brought membrane potentials closer to EK (the Nernst potential for K+ ions), suggesting activation of a K+ conductance. This occurred at potentials much more negative than the activation range for delayed rectifier channels (Kv). 4. Forskolin (1 microM) caused hyperpolarization and a leftward shift in the dose-response relationship for Ba2+, suggesting that forskolin may activate a Ba2+-sensitive conductance. 5. Patch-clamp recordings from interstitial cells of Cajal (ICC) revealed the presence of a Ba2+-sensitive inward rectifier potassium conductance. Far less of this conductance was present in smooth muscle cells. 6. Kir2.1 was expressed in the circular muscle layer of the canine proximal colon, duodenum, jejunum and ileum. Kir2.1 mRNA was expressed in greater abundance along the submucosal surface of the circular muscle layer in the colon. 7. These results demonstrate that ICC express a Ba2+-sensitive conductance (possibly encoded by Kir2.1). This conductance contributes to the generation and maintenance of negative membrane potentials between slow waves.

Synergistic effect of heat and sodium lactate on the thermal resistance of Yersinia enterocolitica and Listeria monocytogenes in minced beef.

The effect of sodium lactate (NaL) (0, 2.4 or 4.8%), in heating and recovery media, on Yersinia enterocolitica and Listeria monocytogenes numbers recovered from minced beef heated at 55 degrees C, was examined. Survivors were enumerated on selective media at pH 5.7/7.4 (Y. enterocolitica) or pH 5.7/7.2 (L. monocytogenes). Recovery of the organisms depended on the pH and NaL levels in the recovery medium. The heat resistance of Y. enterocolitica (P < 0.001) and L. monocytogenes (P < 0.01) decreased as the concentration of NaL in the minced beef increased from 0 to 2.4% or 4.8%. The thermal destruction of pathogens in foods processed using mild temperatures may be enhanced by the addition of 2.4% NaL.

The use of a surface adhesion immunofluorescent (SAIF) method for the rapid detection of Yersinia enterocolitica serotype O:3 in meat.

This study examined the attachment kinetics of Yersinia enterocolitica serotype O:3 to determine the optimum conditions for its isolation from meat enrichment systems using a novel surface adhesion technique. Minced beef was inoculated with Y. enterocolitica at an initial level of 10 cfu g-1 and incubated at 25 degrees C in an enrichment broth. Yersinia was recovered from enriched samples on polycarbonate membranes by surface adhesion and enumerated using immunofluorescence microscopy. The surface adhesion immunofluorescence technique (SAIF) had a minimum detection limit of approximately 4.0-4.5 log10 cfu ml-1 and provided good correlation between the estimation of the numbers of Yersinia in the enrichment broth derived from plate counts on Yersinia Selective agar (CIN) and those determined by SAIF (r2 = 0.94; rsd = +/- 0.21). A derived regression equation of the SAIF count vs plate counts was used to predict Y. enterocolitica numbers in spiked meat samples stored at 0 degree C for up to 20 d. The numbers as predicted by the SAIF method showed good correlation with counts derived by plating techniques (r2 = 0.78; rsd = +/- 0.42). The application of the SAIF technique for the rapid detection of Y. enterocolitica serotype O:3 from meat is discussed.

A study of the growth kinetics of Yersinia enterocolitica serotype O:3 in pure and meat culture systems.

The growth kinetics of a virulence plasmid-bearing (P+) and a plasmid-cured (P-) strain of Yersinia enterocolitica serotype O:3 in pure and meat culture were investigated. Growth studies were carried out at 25 and 37 degrees C in supplemented phosphate-buffered saline, buffered peptone water, cefsulodin-irgasan-novobiocin broth base or supplemented broth base (CIN). The lag phase durations and growth rates under these conditions were determined by linear regression analysis. In pure culture, under most sets of equivalent conditions, P+ and P- strains had similar lag phase durations. However, under one set of conditions, i.e. CIN broth at 37 degrees C, the lag phase duration of the P+ strain was significantly longer than P-. In all but the most selective medium, P+ strains had slower growth rates that P- strains at 37 degrees C, probably due to the increase metabolic burden entailed in the maintenance of the virulence plasmid. In the most selective medium, i.e. CIN broth, P+ strains grew significantly faster than P-. This finding suggests that possession of virulence plasmid confers an enhanced ability to grow in the presence of selective agents. In meat cultures, both strains had longer lag phase than in equivalent pure cultures, with longer lag phases noted at 37 than at 25 degrees C. No significant differences were observed between the length of lag phases of P+ and P strains in meat culture. Both strains of Y. enterocolitica displayed faster growth rates in meat cultures than in pure cultures, indicating that one of more components of meat enhanced the growth of this organism. The effects and interaction of incubation temperature, enrichment broth and meat on the growth kinetics of plasmid-bearing and plasmid-cured Y. enterocolitica strains are discussed.

Tests of vaginal microbicides in the mouse genital herpes model.

Microbicide candidates were selected that have demonstrated activity against sperm or sexually transmitted disease pathogens in vitro, and the efficacy of these agents for preventing vaginal transmission of genital herpes infection was evaluated in the progestin-treated mouse. Each agent was delivered to the vaginas of mice approximately 20 sec prior to delivering a highly infectious herpes simplex virus-2 inoculum. The following agents provided significant protection: anti-HSV monoclonal antibodies III-174 and HSV8, modified bovine beta-lactoglobulin (beta-69), carrageenan, concanavalin A, chlorhexidine, dextran sulfate (average molecular weight 8,000 and 500,000), fucoidan, neem, nonoxynol-9, polystyrene sulfonate, and povidone-iodine. Two agents, gramicidin and heparan sulfate, though highly effective in vitro, were not protective in vivo at the doses tested.

Three-dimensional treatment planning of astrocytomas: a dosimetric study of cerebral irradiation.

To demonstrate that 3-dimensional planning is both practical and applicable to the treatment of high-grade astrocytomas, 50 patients over a 2-year period have received cerebral irradiation delivered in focussed, non-axial techniques employing from 2 to 5 beams. Astrocytomas have been planned using rapid, practical incorporation of CT data to define appropriate tumor volumes. Tumor + 3.0 cm and tumor + 1.5 cm volumes have been treated to conventional doses of 4500 cGy and 5940 cGy, respectively, using beam orientations that maximally spared normal remaining parenchyma. Analyses of 3-dimensionally calculated plans have been performed using integral dose-volume histograms (DVH) to help select treatment techniques. Using identical CT-based volumetric data as input for generation of Beam's Eye View (BEV) designed blocks, DVH curves demonstrate dosimetric advantages of non-axial techniques over conventional parallel-opposed orientations. Assessment of the non-axial techniques in selected cases indicates that uniform target volume coverage could be maintained with a typical reduction of 30% in the total amount of brain tissue treated to high dose (95% isodose line).

Intra-arterial bromodeoxyuridine radiosensitization of malignant gliomas.

In the 1950's it was first observed that mammalian cells exposed to the halogenated deoxyuridines were more sensitive to ultraviolet light and radiation than untreated cells. This prompted early clinical trials with bromodeoxyuridine (BUdR) which showed mixed results. More recently, several Phase I studies, while establishing the feasibility of continuous intravenous (IV) infusion of BUdR, have reported significant dose limiting skin and bone marrow toxicities and have questioned the optimal method of BUdR delivery. To exploit the high mitotic activity of malignant gliomas relative to surrounding normal brain tissue, we have developed a permanently implantable infusion pump system for safe, continuous intraarterial (IA) internal carotid BUdR delivery. Since July 1985, 23 patients with malignant brain tumors (18 grade 4, 5 grade 3) have been treated in a Phase I clinical trial using IA BUdR (400-600 mg/m2/day X 8 1/2 weeks) and focal external beam radiotherapy (59.4 Gy at 1.8 Gy/day in 6 1/2 weeks). Following initial biopsy/surgery the infusion pump system was implanted; BUdR infusion began 2 weeks prior to and continued throughout the 6 1/2 week course of radiotherapy. There have been no vascular complications. Side-effects in all patients have included varying degrees of anorexia, fatigue, ipsilateral forehead dermatitis, blepharitis, and conjunctivitis. Myelosuppression requiring dose reduction occurred in one patient. An overall Kaplan-Meier estimated median survival of 20 months has been achieved. As in larger controlled series, histologic grade and age are prognostically significant. We have shown in a Phase I study that IA BUdR radiosensitization is safe, tolerable, may lead to improved survival, and appears to be an efficacious primary treatment of malignant gliomas.

The ocular effects of intracarotid bromodeoxyuridine and radiation therapy in the treatment of malignant glioma.

Since July 1985, 23 patients have been entered into a phase I/II clinical trial using intraarterial 5-bromodeoxyuridine (BUdR) (400-600 mg/m2 daily for 8.5 weeks) and focal external beam radiotherapy (59.4 Gy at 1.8 Gy daily in 6.5 weeks) in the treatment of malignant gliomas (Kernohan grades 3 and 4). The side effects in all patients have included varying degrees of anorexia, fatigue, ipsilateral forehead dermatitis, blepharitis, and conjunctivitis. Mucopurulent conjunctivitis and exposure keratitis developed in several patients and spontaneous corneal perforation developed in one. Eyes from two individuals examined at autopsy showed significant changes. Animal studies that predated clinical trials using rhesus monkeys did not predict the ophthalmologic complications seen in human subjects.

Mucocutaneous complications of intraarterial 5-bromodeoxyuridine and radiation.

5-Bromodeoxyuridine (BUDR), a halopyrimidine thymidine analogue, is incorporated into the DNA of dividing cells and causes photoradiosensitization. Twenty-five patients with malignant astrocytomas were treated with continuous intracarotid BUDR radiosensitization and radiotherapy for 8 1/2 weeks. Unique dose-limiting mucocutaneous complications were encountered. Ipsilateral facial dermatitis with epilation of eyebrows and eyelashes, ocular irritation, and bilateral nail dystrophy developed in all patients. Less common reactions included oral ulceration in six patients, body exanthem on the trunk in five, and atypical erythema multiforme major in one.

Stage III carcinoma of the endometrium. Results of treatment.

The impact of treatment on survival was analysed in 45 patients with stage III carcinoma of the endometrium. Our results indicate that patients treated with a combination of surgery and radiation therapy did significantly better than those treated with radiation alone. The five-years survival was 57.3% and 17.5%, respectively (p = 0.01). Patients with clinical stage III (CS III) whose tumor could not be resected surgically did poorly than patients with pathological stage III (PS III). This difference, however, was not statistically significant (p = greater than 0.05). Treatment related complications were minimal. Overall survival of patients of 33.8% was directly attributable to increased pelvic and/or extra pelvic recurrences.

Enhancement and depression by inosine of the growth inhibitory action of 5-fluorouracil on cultured Jensen tumor cells.

Continuous exposure of Jensen tumor cells in vitro to 1 mM inosine following a 1 hr exposure to 5-fluorouracil resulted in a 5-fold potentiation of growth inhibition. This effect was abolished by the simultaneous presence of 1 mM cytidine and was attributable to altered metabolic processing of drug anabolites after the uptake of 5-fluorouracil had ceased. In contrast, antagonism to 5-fluorouracil was seen when the cells were exposed successively to 1 mM inosine for 1.5 hr and to 5-fluorouracil for 1 hr. In this case the inhibitory action of the drug was diminished by nearly one-half. Quantitation of the potentiation and antagonism was based upon growth delays measured from growth curves obtained by serial photomicrography.