Radiation dose and magnification in pelvic X-ray: EOS™ imaging system versus plain radiographs.

BACKGROUND: In plain pelvic X-ray, magnification makes measurement unreliable. The EOS™ (EOS Imaging, Paris France) imaging system is reputed to reproduce patient anatomy exactly, with a lower radiation dose. This, however, has not been assessed according to patient weight, although both magnification and irradiation are known to vary with weight. We therefore conducted a prospective comparative study, to compare: (1) image magnification and (2) radiation dose between the EOS imaging system and plain X-ray. HYPOTHESIS: The EOS imaging system reproduces patient anatomy exactly, regardless of weight, unlike plain X-ray. MATERIAL AND METHOD: A single-center comparative study of plain pelvic X-ray and 2D EOS radiography was performed in 183 patients: 186 arthroplasties; 104 male, 81 female; mean age 61.3±13.7years (range, 24-87years). Magnification and radiation dose (dose-area product [DAP]) were compared between the two systems in 186 hips in patients with a mean body-mass index (BMI) of 27.1±5.3kg/m2 (range, 17.6-42.3kg/m2), including 7 with morbid obesity. RESULTS: Mean magnification was zero using the EOS system, regardless of patient weight, compared to 1.15±0.05 (range, 1-1.32) on plain X-ray (P<10-5). In patients with BMI<25, mean magnification on plain X-ray was 1.15±0.05 (range, 1-1.25) and, in patients with morbid obesity, 1.22±0.06 (range, 1.18-1.32). The mean radiation dose was 8.19±2.63dGy/cm2 (range, 1.77-14.24) with the EOS system, versus 19.38±12.37dGy/cm2 (range, 4.77-81.75) with plain X-ray (P<10-4). For BMI >40, mean radiation dose was 9.36±2.57dGy/cm2 (range, 7.4-14.2) with the EOS system, versus 44.76±22.21 (range, 25.2-81.7) with plain X-ray. Radiation dose increased by 0.20dGy with each extra BMI point for the EOS system, versus 0.74dGy for plain X-ray. CONCLUSION: Magnification did not vary with patient weight using the EOS system, unlike plain X-ray, and radiation dose was 2.5-fold lower. LEVEL OF EVIDENCE: 3, prospective case-control study.

Costing methodology in laparoscopic surgery.

This paper provides some basic insights in economic evaluation and costing methodology by means of illustrations in the field of laparoscopic surgery. Some general methodological aspects are discussed, as well as their impact on the calculation of both societal and hospital costs of medical interventions. First, Health Care Technology Assessment is described, and several techniques of economic evaluation in health care are situated in this area. Two fundamental concepts in costing analysis are discussed : opportunity costs and marginal (or incremental) analysis. Furthermore, it is argued that in designing an economic analysis, sufficient attention should be given to delineating the alternative treatment options and to determining the perspective from which the study is performed (patient, hospital, insurer, society,...). Subsequently, it is argued that all price and wage data for activities performed within a certain period should apply to the same time period. Finally, in order to facilitate overview, re-calculation and interpretation of cost data, it is advised to distinguish fixed from variable costs. Different categories of societal costs are described, as well as a number of methodologies for their evaluation. In calculating hospital costs, the costs of all different resources used (e.g. buildings, equipment, staff, materials) must be identified precisely. The issues of annuitising initial investment expenses, calculating operating and maintenance costs, and allocating labour and overhead costs are discussed. Finally, it is argued that, in all studies, it should be investigated whether the results of the economic analysis are robust to the models' assumptions, by means of sensitivity analysis. This paper provides a practical toolkit for medical doctors, to allow a correct understanding and critical analysis of economic literature in the field of laparoscopic surgery.

Preliminary study on the presence of prednisolone in porcine urine and liver - How to distinguish endogenous from therapeutically administered prednisolone.

In animal breeding in Europe, synthetic corticosteroids are not allowed as growth-promoting agents. However, prednisolone residues have recently been found in porcine urine samples collected at slaughterhouses. The aim of this work was therefore to look for prednisolone in porcine urine and liver, to determine if detected residues might be of endogenous origin, and to check the possible relation with stress. An analytical method developed in-house was validated, combining immunoaffinity-based purification and ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). This method was applied to urine and liver samples collected from sows experimentally treated either with prednisolone or tetracosactide hexaacetate (synthetic analogue of ACTH). Thanks to the performance of the analytical method, both cortisol and prednisolone were detected in all pig urine samples collected before or after administration of prednisolone or tetracosactide hexaacetate. High levels of prednisolone were found in porcine urine just after prednisolone administration, decreasing quickly to within the range detected in non-treated animals. In urine, the cortisol level varied depending on the time lapse between administration and sampling. On the other hand, prednisolone was detected also in liver samples of treated pigs. In this matrix, the cortisol level remained constant and prednisolone/cortisol level could be used to detect prednisolone administration at least 4 days after injection. In conclusion, the best indicator for detecting illicit prednisolone administration to pigs seems to be the prednisolone/cortisol ratio in liver samples. This preliminary work must be confirmed by a larger-scale study and metabolites should also be included.

Development of ELISAs for detecting domoic acid, okadaic acid, and saxitoxin and their applicability for the detection of marine toxins in samples collected in Belgium.

Okadaic acid, a diarrhetic shellfish poison, domoic acid, an amnesic shellfish poison, and saxitoxin, a paralytic shellfish poison, are three of the best-known marine biotoxins. The mouse bioassay is the method most widely used to detect many of these toxins in shellfish samples, but animal welfare concerns have prompted researchers to seek alternative methods of detection. In this study, three direct competitive enzyme-linked immunosorbent assays (ELISAs), each based on antibodies raised in rabbits against a conjugate of the analyte of interest, were developed for marine biotoxin detection in mussel, oyster, and scallop. One assay was for okadaic acid, one for saxitoxin, and one for domoic acid usually detected and quantified by high-performance liquid chromatography-ultraviolet light (HPLC-UV). All three compounds and a number of related toxins were extracted quickly and simply from the shellfish matrices with a 9 : 1 mixture of ethanol and water before analysis. The detection capabilities (CCbeta values) of the developed ELISAs were 150 microg kg(-1) for okadaic acid, 50 microg kg(-1) for domoic acid, and 5 microg kg(-1) or less for saxitoxin. The assays proved satisfactory when used over a 4-month period for the analysis of 110 real samples collected in Belgium.

A cost comparison of disposable vs reusable instruments in laparoscopic cholecystectomy.

BACKGROUND: This paper compares the costs of disposable and reusable instruments in laparoscopic cholecystectomy. METHODS: The instrument set considered includes those instruments that are available in both a reusable and disposable form. A market study within the Belgian market was performed in order to compare purchase prices. In addition, costs of cleaning, sterilization, wrapping, maintenance, repair, and disposal of waste were calculated. The effects of reusables and disposables were examined by means of a literature overview. RESULTS: It was calculated that the instrument cost per procedure of a full disposable set is 7.4-27.7 times higher than the cost per procedure with reusables. In comparison with disposables, modular systems ("semidisposable") and mixed use of disposables and reusables reduce costs, but still the cost per procedure remains higher than with reusables. A sensitivity analysis confirmed that these conclusions are robust to the model assumptions. In addition, the available evidence in the literature suggests that reusables do not compromise patient or staff safety. CONCLUSIONS: If reusables are used instead of disposables when performing a laparoscopic cholecystectomy, considerable savings can be achieved without compromising patient and staff safety.

[In vitro study of the susceptibility of mycobacteria to sulfonamides by the disc and percentage methods (author's transl)]. / Etude in vitro de la sensibilité des mycobactéries aux sulfamides, par les méthodes des disques et des proportions.

Disc method is used as a preliminary qualitative test, in order to check the mycobacterial susceptibility to sulfadiazine and cotrimoxazole, while the percentage method gives a quantitative antibiogram in testing with precision the microbial susceptibility to sulfadiazine, sulfamethoxazole, sulfamethoxydiazine, sulfadimethoxine and cotrimoxazole. Both methods are performed in tube, on Löwenstein-Jensen medium. The mycobacteria tested include 114 strains representing 10 species. The results show that sulfonamides and cotrimoxazole exert an inhibitory power which can vary according to the species : it is excellent for M. fortuitum, M. kansasii, M. marinum, M. scrofulaceum, M. szulgai and M. xenopi, weaker for M. ulcerans, mediocre for M. avium and M. tuberculosis, non existent for M. bovis. The percentage method shows that the MIC is less with cotrimoxazole and sulfamethoxazole than with other sulfonamides. Within the same species as M. avium, there are marked differences of bacterial susceptibility to these antibacillaries, according to the strains.

[Antibiogram of mycobacteria for erythromycin, tetracycline and cotrimoxazole]. / Antibiogramme des mycobactéries pour l'érythromycine, la tétracycline et le cotrimoxazole.

Disc method checks the bacterial susceptibility to erythromycin, tetracycline and cotrimoxazole, while the percentage method determines the MIC and the proportion of resistant bacilli at a critical concentration. The mycobacteria include 113 strains representing 12 species. Both methods show that cotrimoxazole is more active on germs than the other substances. Nevertheless, the sensitivity varies with the species, according to the technique. As the proportion method is a more reliable test to establish the susceptibility of mycobacteria, we have only used this technique to determine the activity spectrum of the various drugs. Specifically, M. marinum, M. scrofulaceum and M. szulgai are inhibited by the three substances, while M. kansasii, M. ulcerans and M. xenopi are especially sensitive to cotrimoxazole and erythromycin. M. fortuitum and M. haemophilum are particularly sensitive to cotrimoxazole, while they are resistant to erythromycin and tetracycline. It is the contrary with M. chelonei. M. avium and M. tuberculosis are sensitive to erythromycin and cotrimoxazole, but to a lower degree, while M. bovis does not respond to any drugs.

[Rectal ulcer infected by Mycobacterium fortuitum. Apropos of 4 cases]. / Ulcère rectal infecté par Mycobacterium fortuitum. A propos de quatre cas.

From October 1986 to November 1988, 4 cases of rectal ulcers from which M. fortuitum was isolated were observed. The patients, all women, were respectively 24, 83, 85 and 86 years old. The complaints were: anorectal pain, rectal bleeding and stools mixed with glairy material. The ulcers were situated in the anterior, posterior or lateral wall of the rectum; one of these perforated in the perirectal space with development of a local abscess. The presence of M. fortuitum in the lesions was established by detection of mycobacteria in the smear (2 cases) or in the histological section (1 case), and by positive cultures (all cases). All strains were susceptible to aminoglycosides, quinolones (except 2), macrolides and to imipenem. They were resistant to current antituberculous drugs, to tetracycline and to beta-lactamines. Two patients healed, one spontaneously and the other one with antibiotics (amikacin and norfloxacin for 3 months); two patients died, one because of cardiac failure and intercurrent infection and the other one after rectal bleeding. The histopathological pattern of the lesions was pleomorphic: chronic aspecific inflammatory reaction, granulomatous tissue with Langhans cells (1 cas), necrotic abscesses without caseation, intratissular acid-fast bacilli (1 case). The isolation of M. fortuitum in the rectal ulcers has been discussed.

[Osteoarthritis and tenosynovitis of the finger due to Mycobacterium intracellulare. A case report and review of the literature]. / Ostéo-arthrite et ténosynovite du doigt due à Mycobacterium intracellulare. Observation d'un cas et revue de la littérature.

The authors present one case of osteo-arthritis and tenosynovitis of the right forefinger due to Mycobacterium intracellulare, in a 61-year old woman. The treatment consists of a synovectomy of the finger's proximal interphalangeal joint and of the sheath of the flexor tendons and a drug regimen associating erythromycin and cotrimoxazole for 2 1/2 months. This therapy proves successful, as the patient is clinically cured. A literature review records 19 similar osteo-articular and peri-articular infections due to the Mycobacterium avium-intracellulare group, reported during these last 25 years.

[A case of pulmonary mycobacteriosis due to Mycobacterium intracellulare (author's transl)]. / Un cas de mycobactériose pulmonaire humaine par Mycobacterium intracellulare.

An M. intracellulare, rough strain (serotype 7) has been isolated from sputum of a sixty-year old patients. This patient was a political prisoner in Germany between 1942-1945 and had contracted pulmonary tuberculosis with the cavity in the upper lobe of the right lung. A strain of mycobacterium susceptible to antituberculous drugs was isolated from his sputum in 1973. Since 1979, the isolation of M. Intracellulare has been accompanied by clinical signs of pulmonary mycobacteriosis, i.e. persistence of the cavity in spite of antituberculous treatments reapparition of cough with sputum, general weakness. Intradermo-reaction with specific sensitin gives a strong positive reaction, contrasting with a weak reaction with PPD tuberculin. As the antibiogram of the strain shows a susceptibility to cotrimoxazole and erythromycin, the patient underwent a therapy with the combination sulfamethaxozale-trimethoprime and erythromycin, for 4 months. At the end of this treatment, he seems to have recovered completely. The radiological aspect of the lungs remains unchanged. Although the source of contamination remains unknown, one thinks on the basis of bibliographica data, that it can be found in human beings, or seldom in animals (a pig, a bird) or in nature (a pond).