Using personal monitoring data to derive organ doses for medical radiation workers in the Million Person Study-considerations regarding NCRP Commentary no. 30.

The study of low dose and low-dose rate exposure is of central importance in understanding the possible range of health effects from prolonged exposures to radiation. The One Million Person Study of Radiation Workers and Veterans (MPS) of low-dose health effects was designed to evaluate radiation risks among healthy American workers and veterans. The MPS is evaluating low-dose and dose-rate effects, intakes of radioactive elements, cancer and non-cancer outcomes, as well as differences in risks between women and men. Medical radiation workers make up a large group of individuals occupationally exposed to low doses of radiation from external x-ray/gamma exposures. For the MPS, about 100 000 United States medical radiation workers have been selected for study. The approach to the complex dosimetry circumstances for such workers over three to four decades of occupation were initially and broadly described in National Council on Radiation Protection and Measurements (NCRP) Report No. 178. NCRP Commentary No. 30 provides more detail and describes an optimum approach for using personal monitoring data to estimate lung and other organ doses applicable to the cohort and provides specific precautions/considerations applicable to the dosimetry of medical radiation worker organ doses for use in epidemiologic studies. The use of protective aprons creates dosimetric complexity. It is recommended that dose values from dosimeters worn over a protective apron be reduced by a factor of 20 for estimating mean organ doses to tissues located in the torso and that 15% of the marrow should be assumed to remain unshielded for exposure scenarios when aprons are worn. Conversion coefficients relating personal dose equivalent,Hp(10) in mSv, to mean absorbed doses to organs and tissues,DTin mGy, for females and males for six exposure scenarios have been determined and presented for use in the MPS. This Memorandum summarises several key points in NCRP Commentary No. 30.

Neutron field characterisation at mixed oxide fuel plant.

A neutron field characterisation was conducted at the AREVA Melox Plant to determine the response of passive and active neutron dosemeters for several stages in the mixed oxide fuel manufacturing process. Landauer Europe provides radiation dosimetry to many contractors working at the Melox site. The studies were conducted to assist in determining the neutron radiation fields the workers are exposed to routinely, evaluate the need for specific neutron correction factors and to ensure that the most accurate neutron dose is reported for the Melox Plant workers.

Neutron response characterisation of an OSL neutron dosemeter.

The neutron response was characterised for Al(2)O(3):C material coated with (6)Li(2)CO(3). Al(2)O(3):C material, an optically stimulated luminescent (OSL) dosemeter, which is sensitive to both photons and beta radiation but is mostly insensitive to neutron radiation. The Al(2)O(3):C material was coated with (6)Li(2)CO(3) to create a material sensitive to neutrons, beta and photon radiation. In this paper, the neutron response of this new OSL material (OSLN) will be compared with various other neutron measurement technologies in laboratory and field environments.

A method to characterise site, urban and regional ambient background radiation.

Control dosemeters are routinely provided to customers to monitor the background radiation so that it can be subtracted from the gross response of the dosemeter to arrive at the occupational dose. Landauer, the largest dosimetry processor in the world with subsidiaries in Australia, Brazil, China, France, Japan, Mexico and the UK, has clients in approximately 130 countries. The Glenwood facility processes over 1.1 million controls per year. This network of clients around the world provides a unique ability to monitor the world's ambient background radiation. Control data can be mined to provide useful historical information regarding ambient background rates and provide a historical baseline for geographical areas. Historical baseline can be used to provide site or region-specific background subtraction values, document the variation in ambient background radiation around a client's site or provide a baseline for measuring the efficiency of clean-up efforts in urban areas after a dirty bomb detonation.

Efficacy and safety of cefovecin for the treatment of urinary tract infections in cats.

OBJECTIVES: To determine the efficacy and safety of cefovecin (Convenia); Pfizer Animal Health) in the treatment of urinary tract infections in cats. METHOD: A multi-centre, masked, randomised study was conducted in cats presenting with clinical signs indicative of urinary tract infections. Cephalexin (Rilexine); Virbac) administered orally twice daily at 15 mg/kg bodyweight for 14 days was compared with a single subcutaneous injection of cefovecin in cats. The primary efficacy parameter assessed was bacterial elimination of the pretreatment uropathogen. RESULTS: Four hundred and thirty-four cats were screened for urinary tract infections. One hundred and eighty-five cats were treated with either cefovecin (n=124) or cephalexin (n=61). Ninety-seven cats (22.2 per cent) had confirmed bacteriuria and 82 cats were included in efficacy analysis. Escherichia coli was eliminated in 76.7 per cent (23 of 30) of cefovecin-treated cats compared with 62.5 per cent (10 of 16) of cephalexin-treated cats. Cefovecin demonstrated statistical non-inferiority compared with cephalexin for bacterial elimination. There were no suspected adverse drug reactions attributable to treatment with cefovecin or cephalexin. CLINICAL SIGNIFICANCE: Cefovecin was demonstrated to be an effective and safe treatment for urinary tract infections.

The efficacy and safety of cefovecin in the treatment of feline abscesses and infected wounds.

OBJECTIVES: To determine the efficacy and safety of cefovecin for the treatment of bacterial abscesses and wounds in cats at clinics in Germany, France, Spain and the UK. METHOD: Cats with abscesses or wounds were enrolled. Cats (217) were randomised to treatment with either cefovecin administered by subcutaneous injection at 14 day intervals or amoxicillin/clavulanic acid as twice-daily oral tablets for 14 days. Treatment courses were repeated at 14 day intervals, when deemed necessary. Clinicians assessing lesions were masked to treatment allocation. Only animals with a confirmed pretreatment bacterial pathogen were included in the efficacy analysis. Cases were evaluated 28 days after initiation of the final course of treatment. RESULTS: Cefovecin was as efficacious as amoxicillin/clavulanic acid, and efficacy was 100 per cent for both treatments. CLINICAL SIGNIFICANCE: Cefovecin, administered as a single subcutaneous injection repeated at 14 day intervals as required, was shown to be as efficacious as oral amoxicillin/clavulanic acid in the treatment of abscesses/wounds in cats.

Clinical efficacy and safety of cefovecin in the treatment of canine pyoderma and wound infections.

OBJECTIVES: To determine the efficacy and safety of cefovecin in the treatment of bacterial skin infections in dogs. METHOD: Dogs with superficial or deep pyoderma or wounds/abscesses were enrolled in three separate studies. Dogs (354) were randomised to treatment and received either cefovecin administered by subcutaneous injection at 14 day intervals, as clinically necessary, or amoxicillin/clavulanic acid as oral tablets twice daily for 14 days. Courses of treatment were repeated at 14 day intervals up to a total of four courses. Clinicians responsible for assessing lesions were masked to treatment allocation. Only animals where the presence of a pretreatment bacterial pathogen was confirmed were included in the analysis of efficacy. Cases were evaluated for clinical efficacy at 28 days after initiation of the final course of treatment. Clinical efficacy was assessed by scoring the clinical signs typical of skin infections. RESULTS: Cefovecin demonstrated statistical non-inferiority compared with amoxicillin/clavulanic acid for all three clinical diagnoses; for cefovecin, up to 96.9 per cent efficacy was observed versus 92.5 per cent for amoxicillin/clavulanic acid. CLINICAL SIGNIFICANCE: Cefovecin was shown to be as effective as amoxicillin/clavulanic acid administered orally in the treatment of bacterial skin infections in dogs. Cefovecin offers the additional benefit of eliminating owner non-compliance.

Efficacy and safety of cefovecin (Convenia) for the treatment of urinary tract infections in dogs.

OBJECTIVES: To determine the efficacy and safety of cefovecin (Convenia); Pfizer Animal Health) in the treatment of urinary tract infections in dogs. METHODS: A multi-centre, blinded, randomised study was conducted in 129 dogs with urinary tract infections. Cephalexin (Rilexine) administered twice daily at 15 mg/kg bodyweight orally for 14 days was compared with a single, subcutaneous injection of cefovecin (Convenia) in dogs. The primary efficacy parameter assessed was bacterial elimination of the pretreatment uropathogen. RESULTS: One hundred and twenty-nine dogs were included in efficacy assessments. Escherichia coli was eliminated in 90.5 per cent of cefovecin-treated dogs compared with 52.9 per cent of cephalexin-treated dogs (P=0.0004). Overall cure rates for dogs with Escherichia coli infections were 79.1 per cent for cefovecin and 36.4 per cent for cephalexin-treated dogs (P=0.0003). There were no suspected adverse drug reactions attributed to treatment with cefovecin or cephalexin. CLINICAL SIGNIFICANCE: Cefovecin was shown to be an effective and safe treatment for urinary tract infections.

Antimicrobial activity and spectrum of cefovecin, a new extended- spectrum cephalosporin, against pathogens collected from dogs and cats in Europe and North America.

Cefovecin is a new extended-spectrum semisynthetic cephalosporin indicated for the treatment of bacterial infections in dogs and cats. This study evaluated the in vitro activity and spectrum of cefovecin against 2,641 recent clinical isolates (1,660 canine and 981 feline isolates) from Europe and the United States. MIC determinations against cefovecin and other reference antimicrobials were performed by broth microdilution methods recommended by the Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS). Cefovecin demonstrated bactericidal activity against both gram-positive and gram-negative pathogens. Cefovecin exhibited in vitro activity against all major aerobic and anaerobic bacterial pathogens associated with skin, urinary tract, and periodontal infections in dogs and cats. The MIC90 values of cefovecin against Staphylococcus intermedius, Escherichia coli, and Pasteurella multocida were 0.25 microg/ml, 1.0 microg/ml, and 0.06 microg/ml, respectively. No significant differences were observed in terms of the activities of cefovecin against pathogens from different European countries and against pathogens of European and U.S. origin.

AVP (4-8) improves concept learning in PFC-damaged but not hippocampal-damaged rats.

A position reversal task was used to test the memory-enhancing effects of the arginine vasopressin analog [pGlu4, Cyt6] AVP (4-8) at a dose of 1.5 microg/kg. Rats received either sham operations (SHM), medial prefrontal cortex lesions (PFC), or hippocampal lesions (HIP). The peptide was administered daily, via s.c. injection, 30 min prior to training to half of the animals in each group. As expected, all animals performed equally well on the initial position habit and the first reversal. Overall, it was found that AVP (4-8)-treated animals performed significantly better across trials than saline (SAL)-treated animals. Further analysis showed that PFC animals that received AVP (4-8) (PFC+AVP) performed significantly better (at the level of controls) across trials than saline-treated PFC (PFC+SAL) animals. Sham animals that received the AVP (4-8) analog (SHM+AVP) only showed significant improvement on the last two reversals when compared to the sham saline-treated animals (SHM+SAL), which was likely due to a ceiling effect as performance reached high levels early in the reversal task. Trial 2 analysis across reversals revealed enhanced cognitive abilities in both sham groups (SHM+SAL, SHM+AVP) and the PFC+AVP group, but not in the PFC+SAL, HIP+AVP or the HIP+SAL groups. Hippocampal lesioned animals performed poorly on the task and injections of AVP (4-8) did not improve their performance. It is thus concluded that AVP (4-8) enhanced the acquisition of concept learning (win-stay/loose-shift) in this paradigm in PFC-damaged animals and ameliorated the perseverance habit that is often seen in PFC animals on this task. It is suggested that AVP (4-8) might have an enhancing effect on general cognitive abilities that is not limited to memory processes.

Job satisfaction of family practice residents.

BACKGROUND AND OBJECTIVES: As new market forces and expanding responsibilities strongly influence our specialty, it is vital to understand issues that affect resident recruitment, retention, and performance. This study evaluated family practice residents' satisfaction with their chosen careers, their individual programs, and many of the other factors that potentially influence and contribute to job satisfaction. METHODS: Data were collected using a 56-item questionnaire that included demographic information and specific questions regarding residency job satisfaction. The questionnaire was mailed to all 28 Texas family practice residency programs. RESULTS: We received resultsfrom 75% of surveyed residents. Overall satisfaction with family practice as a specialty" received the highest satisfaction ranking. Satisfaction with 25 various aspects of family practice residency training was significantly higher in community-based programs, compared with university-based programs, and satisfaction increased with year level of training. Items that were ranked higher by community-based residents included satisfaction with their specific residency program, obstetrics experience, overall learning environment, degree of autonomy, and relationship with specialists. CONCLUSIONS: This report demonstrates a strong degree of overall job satisfaction among family practice residents. In general, residents in community-based programs have a higher level of job satisfaction, compared with residents in university-based programs, and satisfaction increases with vear level of training.

Design of an intravaginal ring for the controlled delivery of 17 beta-estradiol as its 3-acetate ester.

Suitable ester prodrugs of 17beta-estradiol are identified, thus permitting effective sustained and controlled estrogen replacement therapy (ERT) from an elastomeric, silicone intravaginal ring (IVR). IVR devices of reservoir design were prepared by blending silicone elastomer base with n-propylorthosilicate (cross-linker) and 10% w/w of 17beta-estradiol or an ester prodrug, the mix being activated with 0.5% w/w stannous octoate and cured at 80 degrees C for 2 min. A rate-controlling membrane was similarly prepared, without the active agent. IVR devices were of cross-sectional diameter 9 mm, outer diameter 54 mm, with core cross-sectional diameter of 2 mm and core length varied as required. Sink conditions were evident for the 17beta-estradiol esters in 1.0% aqueous benzalkonium chloride solution. The low release rates into 0.9% w/v saline of the lipophilic valerate and benzoate esters were due to their intrinsically low aqueous solubilities. In vivo, these esters failed to raise plasma estradiol above baseline levels in postmenopausal human volunteers, despite good in vitro release characteristics under sink conditions. The best release rates under sink conditions, in combination with substantial aqueous solubilities as indicated by the release rates into saline, were observed for the acetate and propionate esters. A combination of drug release characteristics, short plasma half-life and a toxicologically acceptable hydrolysis product indicated that 17beta-estradiol-3-acetate was the prodrug of choice for IVR delivery of ERT. In vivo, an IVR device releasing 100 microg/day of estradiol as its 3-acetate ester maintained over 84 days a circulating plasma concentration in the region of 300 pmoll(-1), within the clinically desirable range for ERT.

Short-lived effects of a formulary on anti-infective prescribing--the need for continuing peer review?

Because of the introduction of indicative drug budgets in the UK and their likely association with prescribing from a drug formulary, we have studied the effect of the introduction without continued reinforcement of a voluntary practice formulary on antimicrobial prescribing in a group practice. Detailed prescribing feedback for two matched periods before and after the launch of the Northern Ireland Faculty of the Royal College of General Practitioners practice formulary was compared. The parameters chosen were adherence to the formulary, generic prescribing and costs. A slight increase in prescriptions dispensed (3.5%) was observed between the two periods but prescribing costs increased by 32%. There was a 5.9% fall in the number of prescriptions for formulary agents following the launch of the formulary and a major increase (60%; P < 0.01) in the use of non-formulary antimicrobials particularly penicillins and tetracyclines. It was concluded that the high level of formulary prescribing prevalent during the production of the formulary was not maintained following its launch probably because of the lack of reinforcement.

Antibiotic prescribing: the need for a policy in general practice.

OBJECTIVE: To see whether changes in prescribing of oral antibacterials in Northern Ireland show the need for a community antibiotics policy. DESIGN: Analysis of prescribing totals for several oral antibiotics obtained retrospectively from the prescription pricing bureau for the years 1983-7. SETTING: Audit of anti-infective prescribing in general practice in Northern Ireland over five years. MAIN OUTCOME MEASURE: Respective usage of agents defined as "common" and "occasional" in 1983. RESULTS: There was a gradual decrease in the relative use of common agents from 82% of the total in 1983 to 77% in 1987 together with a complementary increase in the use of occasional agents from 5% to 10%. Pronounced changes were noted in the use of amoxycillin, ampicillin, erythromycin, minocycline, doxycycline, and amoxycillin-clavulanic acid. CONCLUSION: Though this survey found reasonably conservative prescribing, the trend towards increased use of occasional agents has both clinical and cost implications which could be addressed by the use of a prescribing formulary.

Metronidazole excretion in human milk and its effect on the suckling neonate.

1. Milk and plasma metronidazole and hydroxymetronidazole concentrations were measured in 12 breast-feeding patients following multiple doses of metronidazole (400 mg three times daily). All patients received metronidazole in combination with other broad spectrum antibiotics. 2. Plasma concentrations of both parent drug and metabolite were measured in seven suckling infants. Thirty-five infants were monitored for adverse reactions to maternal metronidazole therapy and two further groups of suckling infants, those whose mothers received either ampicillin alone or no drug therapy, were recruited as controls. 3. The mean milk to plasma ratio (M/P) was 0.9 for metronidazole and 0.76 for hydroxymetronidazole while the mean milk metronidazole concentrations (around Cmax) were 15.5 micrograms ml-1. The mean milk hydroxymetronidazole concentration was 5.7 micrograms ml-1. 4. Infant plasma metronidazole concentrations ranged from 1.27 micrograms ml-1 to 2.41 micrograms ml-1, and the corresponding hydroxymetronidazole concentrations from 1.1 to 2.4 micrograms ml-1. 5. There were no significant increases in adverse effects in infants which could be attributable to maternal metronidazole therapy. 6. Metronidazole was excreted in milk at concentrations which caused no serious reactions in the infants studied. The drug may therefore be administered at doses of 400 mg three times daily to mothers wishing to breast-feed their infants.

Drugs taken by mothers in the puerperium: inpatient survey in Northern Ireland.

In an inpatient survey the medication records of 2004 mothers both breast and bottle feeding were examined and the drugs taken in the early postnatal period recorded. No notable differences existed between the types of drugs prescribed for breast feeding and bottle feeding mothers. Iron, vitamins, and mild analgesics were taken routinely by the population, and antibiotics, laxatives, and hypnotics were frequently prescribed. A wide range of other drugs and preparations were taken or used. Although data were available for some of the drugs, there were many whose concentrations in breast milk and potential risk to the suckling infant were unknown. Data are urgently required on hypnotics, narcotic analgesics, antiemetics, antihistaminics, and some antimicrobial agents with respect to their concentrations in breast milk and their safety for the suckling infant.