Cleaning of used rotary nickel-titanium files in an ultrasonic bath by locally intensified acoustic cavitation.

AIM: To compare the pre-sterilization cleaning of rotary Ni-Ti files of different sizes previously used a. ex vivo and b. clinically by a washer-disinfector, a regular ultrasonic bath, and the same ultrasonic bath in combination with a recently developed cavitation intensifying method. METHODOLOGY: Two sets of two hundred rotary Ni-Ti files, one previously used ex vivo and another one used clinically, were collected from the undergraduate and postgraduate clinics of the Academic Centre for Dentistry Amsterdam (ACTA). The instruments were immersed in an enzymatic solution and subsequently cleaned either by a washer-disinfector, a regular ultrasonic bath combined with a glass beaker, the same bath combined with a beaker lined with two cavitation intensifying sheets or with two standard plastic sheets. The positive control consisted of used files that did not undergo any cleaning and the negative control included new unused files. The instruments were then stained to reveal remaining protein material and scored under a stereoscopic microscope. The results were analysed by nonparametric statistical tests (α = 0.05). RESULTS: No significant difference was found between the combination of the ultrasonic bath and the regular glass beaker and the same ultrasonic bath with the beaker lined with the cavitation intensifying sheets. The washer-disinfector left significantly more debris compared to the latter group when clinically used files were evaluated (P ≤ 0.001). The effect of instrument size on cleaning was not consistent. CONCLUSION: None of the tested methods was able to remove all residual protein material from the files; however, it could be noted that this study did not follow the reprocessing protocol provided by the manufacturer.

Evaluation of ceftiofur crystalline free acid sterile suspension for control of metritis in high-risk lactating dairy cows.

Two studies were conducted to determine if clinical metritis could be prevented or decreased in at-risk lactating dairy cows by a single treatment with Excede Sterile Suspension (ceftiofur crystalline free acid sterile suspension [CCFA-SS]) administered within 24 hours after an abnormal calving. Study 1 was a preliminary study and study 2 was a clinical trial (designed to confirm the results of study 1). In both studies, abnormal calving was defined as cows that had dystocia (required assistance), twins, abortion, retained fetal membranes for 12 hours or more, or any combination thereof. A randomized block design with cows blocked on order-of-entry within dairy without regard to parity was used in both studies. In study 1, cows that had abnormal calving from six commercial dairies were randomly assigned to either untreated control (N = 122) or 6.6 mg ceftiofur equivalents/kg of body weight sc in the base of the ear (CCFA-SS, N = 121), within 24 hours after calving. Cows with normal calving during the enrollment period received no treatment and were included for observational purposes (N = 122). Health observations and rectal temperatures were recorded daily, and physical examinations were conducted on Days 1 ± 1, 7 ± 2, 14 ± 2, and 21 ± 2, and uterine swabs (for bacterial culture) were collected from a subsample of cows on Days 3 or 4, 7 ± 2, 14 ± 2, and 21 ± 2. These observations were made by treatment-blinded personnel. In study 2, cows with abnormal calving from 12 commercial dairies were assigned to receive either saline (control, N = 247) or CCFA-SS (N = 247) within 24 hours after calving. Health observations and rectal temperatures were recorded daily, and physical examinations were conducted on Days 0 to 2, 7 ± 1, and 14. In study 1, the incidence of metritis on Day 14 ± 2 was 20.2% versus 36.8% for CCFA-SS and control, respectively, with an odds ratio of 2.30 (P < 0.05). In study 2, incidences of metritis on Day 14 were 28.7% versus 43.5% for CCFA-SS and saline, respectively, with an odds ratio of 1.92 (P < 0.05). Rectal temperatures on Days 1 and 2 and the average for the first 6 days were lower (P < 0.05) for CCFA-SS compared with control cows for both studies. Treatment of cows with a single dose of CCFA-SS within 24 hours after abnormal calving reduced the incidence of subsequent metritis in lactating dairy cows.

Evaluation of two doses of ceftiofur crystalline free acid sterile suspension for treatment of metritis in lactating dairy cows.

The objectives of this study were to evaluate efficacy of a 2-dose regimen of ceftiofur crystalline free acid sterile suspension (CCFA-SS) for treatment of acute metritis in lactating dairy cows under field conditions and to provide additional safety and injection site tolerance data for injections at the base of the ear. Cows at 15 dairies with rectal temperature ≥ 39.5°C and fetid uterine discharge ≤ 10 d postcalving were randomly assigned by blocks of 2, based on order of entry and without regard to parity, to treatment with saline (1.5 mL/45.5 kg of body weight, n=509) or CCFA-SS (6.6 mg of ceftiofur equivalents/kg of body weight, n=514). Treatments were administered by subcutaneous injection in the posterior aspect of the ear where it attaches to the head; the first dose was administered on study d 0 and the second dose was administered in the contra lateral ear on study d 3. Rectal temperatures were recorded on study d 1 to 4 and 5 or 6 and cows were clinically evaluated daily from study d 1 to 13. Cows that exhibited increased adverse clinical signs of poor health or complications associated with metritis were categorized as a treatment failure and administered escape therapy. Each cow received a veterinary physical examination on study d 5 or 6 to determine if she should be removed from the study and on study d 14 to determine clinical cure or failure to cure. Clinical cure was defined as rectal temperature <39.5°C and non-fetid and purulent or mucopurulent discharge on study d 14 and no escape therapy administered. The injection procedure was scored after each injection (study d 0 and 3) and injection sites and ear carriage were scored on study d 5 or 6, 14, and 57±3. Of the 1,023 cows enrolled, 7 were completely censored due to protocol deviations and 34 were removed for protocol deviations or medical conditions not related to metritis. Clinical cure rate was higher for CCFA-SS than for saline (74.3 vs. 55.3%) and rectal temperatures for each of study d 1 to 5 or 6 were lower for CCFA-SS than saline. Injection procedure indices showed that CCFA-SS could be practically and safely administered using commercial dairy facilities. Although injection site scores were higher for CCFA-SS than saline at study d 5 or 6 and 14, ≥98.6% of ears were normal on d 57±3. Thus, a 2-dose treatment with CCFA-SS given 72h apart increased metritis clinical cure rate and was well tolerated in dairy cows.

The US radiation dosimetry standards for 60Co therapy level beams, and the transfer to the AAPM accredited dosimetry calibration laboratories.

This work reports the transfer of the primary standard for air kerma from the National Institute of Standards and Technology (NIST) to the secondary laboratories accredited by the American Association of Physics in Medicine (AAPM). This transfer, performed in August of 2003, was motivated by the recent revision of the NIST air-kerma standards for 60Co gamma-ray beams implemented on July 1, 2003. The revision involved a complete recharacterization of the two NIST therapy-level 60Co gamma-ray beam facilities, resulting in new values for the air-kerma rates disseminated by the NIST. Some of the experimental aspects of the determination of the new air-kerma rates are briefly summarized here; the theoretical aspects have been described in detail by Seltzer and Bergstrom ["Changes in the U.S. primary standards for the air-kerma from gamma-ray beams," J. Res. Natl. Inst. Stand. Technol. 108, 359-381 (2003)]. The standard was transferred to reference-class chambers submitted by each of the AAPM Accredited Dosimetry Calibration Laboratories (ADCLs). These secondary-standard instruments were then used to characterize the 60Co gamma-ray beams at the ADCLs. The values of the response (calibration coefficient) of the ADCL secondary-standard ionization chambers are reported and compared to values obtained prior to the change in the NIST air-kerma standards announced on July 1, 2003. The relative change is about 1.1% for all of these chambers, and this value agrees well with the expected change in chambers calibrated at the NIST or at any secondary-standard laboratory traceable to the new NIST standard.

Ceramic-on-polyethylene bearing surfaces in total hip arthroplasty. Seventeen to twenty-one-year results.

BACKGROUND: Polyethylene wear debris, and the resulting inflammatory response leading to osteolysis and loosening, is the primary mode of failure limiting the longevity of total hip replacements. Alternative bearing surfaces, including ceramic-on-polyethylene, have been investigated in an effort to decrease the amount of polyethylene wear debris. The purpose of this study was to evaluate the seventeen to twenty-one-year results of the use of ceramic-on-polyethylene total hip prostheses. METHODS: Sixty-four total hip prostheses were implanted with cement, by one surgeon, in fifty-six patients from 1978 to 1981. The average age at the index arthroplasty was sixty-nine years (range, fifty-one to eighty-four years). The components consisted of a cemented Charnley-Müller stem with a 32-mm modular alumina femoral head and a cemented all-polyethylene acetabular component. All patients who retained the index prosthesis were assessed clinically with use of Harris hip scores and were evaluated radiographically at the time of the latest follow-up. RESULTS: At the time of this latest follow-up, of the original sixty-four implants, eighteen (28%) were still in place and five (8%) had been revised. The remaining forty-one implants were in patients who had died and were functioning well until the patient's death. No patient was lost to follow-up. Of the eighteen hips with an intact prosthesis in the surviving patients, seven had an excellent clinical result; nine, a good result; and two, a fair result. One asymptomatic hip had definite radiographic evidence of femoral loosening. No hip had definite signs of acetabular loosening or evidence of osteolysis. Survivorship analysis revealed that the probability of survival of the prostheses without revision was 95% at five years, 95% at ten years, 89% at fifteen years, and 79% at twenty years. The mean linear and volumetric polyethylene wear rates were 0.034 mm/yr and 28 mm(3)/yr, respectively. There were no fractures of the ceramic heads. CONCLUSIONS: Outstanding long-term clinical and radiographic results were attained despite the use of what are now considered substandard techniques (an inferior stem design, a 32-mm head, and first-generation cementing techniques). The wear rates in this study are lower than previously reported metal-on-polyethylene wear rates and are consistent with the lowest reported in vivo ceramic-on-polyethylene wear rates. These findings support the consideration of ceramic-on-polyethylene bearing surfaces in total hip arthroplasty.

Women's Health Australia: on the progress of the main cohort studies.

More than 41,000 women aged 18-23, 45-50, and 70-75 years in 1996 are participating in the Australian Longitudinal Study on Women's Health (Women's Health Australia). Baseline surveys were conducted for all three cohorts in 1996, and the first follow-up survey of the mid-age group in 1998 has achieved a response rate exceeding 90%. The main findings so far reflect the large differences in the life experiences of the three cohorts. The young women report high levels of stress. The physical and mental health of those with young children is worse than for those without children, but confounding by sociodemographic characteristics may account for the differences. Two thirds of young women in the healthy weight or underweight range would like to weigh less, and early onset of dieting is associated with poorer physical and mental health. Most of the women in the mid-age group have multiple roles--in paid work, home duties, and caring for children and other dependents. The potential of the study to investigate the long-term impact of such busy lives on health outcomes is considerable. At this stage, the main health issues for these women relate to tiredness, weight gain, and menopause. The older cohort presents a picture of positive aging. These women are heavier users of health services than the mid-age and younger women, and they are also more satisfied with these services. Although their physical health is poorer, their mental health is better, and they report less stress than women in the other two cohorts. The follow-up survey of this group, planned for 1999, will focus on the coping strategies used by these women. An overall goal of the project is to understand the interactions among social roles, life events, and women's health in order to provide a basis for improved health policies and services. Analysis of these interactions, which relies on both quantitative and qualitative data, poses many challenges that will be addressed as the longitudinal data become available.

Choice of GP: who do young rural women prefer?

The demand for female medical practitioners by women in rural areas appears to be increasing and to be age related. However, the distribution of general practitioners in country Australia is heavily weighted to older men and access to a women's health centre also decreases with distance from the metropolitan areas. Data from the Australian Longitudinal Study of Women's Health indicate that young women are significantly more likely than middle-aged or older women to prefer to see a female doctor. It is argued here that it is the 'culture of practice' exhibited by female doctors that young women find attractive, rather than an essential appeal of the gender of the practitioner. The findings suggest that restricted access to female practitioners may affect health outcomes if young rural women are reluctant to seek medical services provided by male doctors practising in traditional modes.

Women's Health Australia: recruitment for a national longitudinal cohort study.

The Women's Health Australia (WHA) project is a longitudinal study of several cohorts of Australian women, which aims to examine the relationships between biological, psychological, social and lifestyle factors and women's physical health, emotional well-being, and their use of and satisfaction with health care. Using the Medicare database as a sampling frame (with oversampling of women from rural and remote areas), 106,000 women in the three age groups 18-23, 45-50 and 70-75 were sent an invitation to participate and a 24-page self-complete questionnaire. Reminder letters, a nation-wide publicity campaign, information brochures, a freecall number for inquiries, and the option of completing the questionnaire by telephone in English or in the respondent's own language, were used to encourage participation. Statutory regulations precluded telephone follow-up of non-respondents. Response rates were 41% (N = 14,792), 54% (N = 14,200) and 36% (N = 12,614) for the three age groups. Comparison with Australian census data indicated that the samples are reasonably representative of Australian women in these age groups, except for a somewhat higher representation of women who are married or in a defacto relationship, and of women with post-school education. The most common reason for non-participation was lack of interest or time. Personal circumstances, objections to the questionnaire or specific items in it, and concerns about confidentiality were the other main reasons. Recruitment of three representative age-group cohorts of women, and the maintenance of these cohorts over a number of years, will provide a valuable opportunity to examine associations over time between aspects of women's lives and their physical and emotional health and well-being.

Measurement of c-erbB-2 proteins in sera from patients with carcinomas and in breast tumor tissue cytosols: correlation with serum tumor markers and membrane-bound oncoprotein.

Using a commercial kit with antibodies against the ectodomain of c-erbB-2 protein, we detected c-erbB-2 immunoreactivity in human serum. We found that the percentages of patients with elevated serum c-erbB-2 immunoreactivities were 35, 21, and 9% in breast, prostate, and ovarian carcinoma, respectively. The majority of the elevated immunoreactivities were associated with sera containing highly elevated tumor markers with the highest in breast carcinoma (35%) and lowest in ovarian cancer (9%). Excellent correlations were also observed between the serum levels of c-erbB-2 immunoreactivity and the dominant tumor markers in serial specimens from individual cancer patients. We could also detect the c-erbB-2 immunoreactivity in the cytosols prepared from the breast tumor tissue for estrogen and progesterone receptor (ER & PgR) measurements using the same commercial kit for serum studies, and the intact c-erbB-2 oncoprotein (p185) in the extracts of the tissue membrane fractions with a different kit designed for tissue extract. The level of c-erbB-2 immunoreactivity in the cytosol from 124 human breast tumor specimens had an excellent correlation with the cell membrane concentrations of p185 (gamma = 0.89). Most of the elevated cytosol c-erbB-2 immunoreactivities were also found to associate with breast tumor specimens containing low concentrations of ER & PgR. It appears that measuring the c-erbB-2 immunoreactivity potentially could be used as a prognostic marker without performing tissue biopsies and also as a serum tumor marker for managing cancer patients.

Additive coclastogenicity of sodium selenite and caffeine in CHO cells treated with N-methyl-N'-nitro-N-nitrosoguanidine.

The clastogenic effect of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in Chinese hamster ovary (CHO) cells and its modulation by Na2SeO3 and caffeine were studied by metaphase analysis of chromosome aberrations (CA) as well as by measuring the formation and repair of single-strand (ss) DNA breaks employing hydroxylapatite chromatography. Treatment of CHO cells with MNNG (1.25 or 2.5 x 10-5M) for 3 h caused CA in 11 and 19% of metaphases scored, respectively. Pretreatment of cells with Na2SeO3 (1-5 micrograms/mL) or caffeine (0.2-2.0 mg/mL) for 2 h resulted in a 2-3.5-fold increase of CA frequency. Addition of both modulators during the mutagen exposure tended to cause a slight inhibition of clastogenic activity of MNNG (1.25 x 10(-5) M) or had no effect on CA number when MNNG was used at a concentration of 2.5 x 10(-5) M). Posttreatment of CHO cells with Na2SeO3 for 20 h after MNNG was ineffective in influencing the number of metaphases with CA, whereas, at these conditions, caffeine enhanced up to 6-7-fold the clastogenic activity of MNNG. Addition of both modulators during the whole experiment, 2 h pretreatment included, resulted in a further significant increase of CA frequency up to the total pulverization of chromosomes in all metaphases scored. The coclastogenic effect of caffeine was greater in this case. The enhancement of chromosome-damaging activity of MNNG by selenite and caffeine was better expressed when this carcinogen was applied at the higher concentration used. An additive coclastogenic effect was observed in CHO cells treated simultaneously with Na2SeO3 and caffeine plus MNNG.(ABSTRACT TRUNCATED AT 250 WORDS)

MHox: a mesodermally restricted homeodomain protein that binds an essential site in the muscle creatine kinase enhancer.

Myogenic helix-loop-helix (HLH) proteins, such as myogenin and MyoD, can activate muscle-specific transcription when introduced into a variety of nonmuscle cell types. Whereas cells of mesodermal origin are especially permissive to the actions of these myogenic regulators, many other cell types are refractory to myogenic conversion by them. Here we describe a novel homeodomain protein, MHox, that binds an A+T-rich element in the muscle creatine kinase (MCK) enhancer that is essential for muscle-specific transcription and trans-activation by myogenic HLH proteins. MHox is completely restricted to mesodermally derived cell types during embryogenesis and to established cell lines of mesodermal origin. In contrast to most other homeobox genes, MHox expression is excluded from the nervous system, with the highest levels observed in limb bud and visceral arches. In adult mice, MHox is expressed at high levels in skeletal muscle, heart and uterus. The DNA-binding properties and pattern of MHox expression are unique among homeobox genes and suggest a role for MHox as a transcriptional regulator that participates in the establishment of diverse mesodermal cell types.

Environment and drug trafficking.

Illicit drug trafficking is a very complex matter, not only because it causes serious and pernicious problems in the socio-economic sphere, but because drug-taking can lead to personal degradation. To this situation, lamentable enough in itself, must be added the immense ecological and environmental damage, which presents grave and serious dangers for the planet.

Xenopus annexin II (calpactin I) heavy chain has a distinct amino terminus.

We have isolated cDNAs encoding annexin II (calpactin I) heavy chain homologues from a Xenopus oocyte cDNA library. Two of the clones are full length, while two appear to be derived from incompletely spliced mRNAs. The 1230- and 1240-base pair full length clones are 99% identical, and both have 84 bases of 5'-untranslated sequence, 1020-base open reading frames, and either 126- or 136-base 3'-untranslated domains. Northern blots show a 1.4-kilobase (kb) annexin II heavy chain transcript throughout oogenesis and in mature eggs. Xenopus annexin II mRNA levels are constant during early embryogenesis, but decrease at 8 h. After midblastula transition, the steady state level of the 1.4-kb transcript increases substantially, and a 3.3-kb transcript appears. Adult brain, heart, striated muscle, and liver contain moderate amounts of the 1.4-kb transcript, while skin has the 3.3-kb transcript and very high levels of the 1.4-kb transcript. Synthetic mRNA derived from the Xenopus annexin II cDNAs directs the synthesis of an apparent Mr = 36,500 polypeptide when microinjected into Xenopus oocytes. The predicted 339-amino acid protein products are 80% identical with murine annexin II heavy chain. Most of the differences are concentrated in the amino end from residues 15 to 24. The Xenopus annexin II heavy chain lacks the highly conserved tyrosine at position 23 which is the site of src oncogene tyrosine kinase phosphorylation in the murine protein. These results demonstrate that Xenopus oocytes contain an annexin II (calpactin I) heavy chain mRNA with a distinct amino terminus and suggest that multiple annexin II isoforms may be expressed during amphibian embryogenesis and development.

Stimulatory effect of potassium ions on MNU- and MNNG-induced mutagenesis in Salmonella typhimurium TA1535 and TA100.

The liquid suspension modification of the standard Salmonella mutagenicity assay employing Ames tester strains of Salmonella typhimurium TA1535 and T100 was used to study the influence of potassium, sodium and calcium on the mutagenic activity of MNU and MNNG. The toxic and mutagenic activities of MNU and MNNG were better expressed when potassium-containing solution was used as a solvent. Short-term pretreatment of bacteria cells with potassium-containing solutions increased the mutagenic efficiency of both chemicals. Potassium-induced increased sensibility of S. typhimurium TA1535 to MNU was completely reversible after 20 min incubation of bacteria in a nutrient broth at 37 degrees C. The mutagenic activity of MNU was reduced after a short-term pretreatment of S. typhimurium TA1535 with a 0.9% solution of CaCl2, while NaCl did not change the mutagenic response of bacteria to MNU.

Inhibition of mutagenicity of a model nitrosation reaction by naturally occurring phenolics, coffee and tea.

Several plant phenolics, one instant coffee, one instant decaffeinated coffee, one roasted coffee, one Japanese tea, one black Indian tea, and one Chinese tea were examined for their inhibitory properties on mutagenicity resulting from the nitrosation of methylurea. Mutagenicity was estimated as the number of his+ revertants per survivor of Salmonella typhimurium TA1535 which was exposed in suspension to the nitrosation mixtures and the modulating agents for 20 min. Tannic acid, gallic acid and chlorogenic acid suppressed the mutagenicity of the model nitrosation system at concentrations similar to or even lower than ascorbic acid. The three tested coffees and three tested teas exerted an inhibitory effect on the mutagenicity of the test system at doses at which they are consumed.

The inhibitory effect of whole and deproteinized saliva on mutagenicity and clastogenicity resulting from a model nitrosation reaction.

The objective of this study was to simulate in vitro at least some of the conditions that prevail in man during ingestion of nitrate and nitrosable compounds. Human saliva has been chosen because most chemicals ingested through food will interact with saliva. The nitrosation of methylurea was used as a model because the nitrosation products can be readily detected by their mutagenic (his+ revertants of S. typhimurium) and clastogenic (chromosome aberrations in CHO cells) properties. The results show that human saliva inhibits the formation of mutagenic and clastogenic nitrosation products when present during nitrosation. A 50% inhibition of mutagenicity results from the addition of a saliva sample diluted at 5% of the original concentration. In the test system used a similar inhibitory effect was obtained by 2.5 mM ascorbic acid or 2.0 mM chlorogenic acid. The main inhibitory agents seem to reside in a deproteinized fraction which was filtered through an ultrafilter UM2 (greater than 1000 MW). At strong acid levels (below pH 2) the saliva loses its inhibitory effect on the nitrosation of methylurea. The contribution of saliva to the inhibition of endogenous nitrosation within the oral cavity or stomach is discussed.