Stress injury of the distal radial growth plate

We report 21 cases of stress injury of the distal radial growth plate-occurring in gymnasts before skeletal maturity. The injury appears to be caused by inability of the growth plate to withstand rotational and compressive forces. Our observations have confirmed that the skeletal age of gymnasts is retarded, which increases the length of time during which the epiphysis is at risk of damage.     

Left ventricular aneurysm formation: an iatrogenic cause for the third mogul

Two cases of left ventricular pseudoaneurysm formation developing post-operatively after mitral valve replacement are reported. The chest radiographs showed an abnormal protuberance on the left heart border at the site of the "third mogul". The definitive diagnosis of this protuberance, resulting from the development of a left ventricular aneurysm, was made on angiography in each case. This site is unusual for left ventricular aneurysm formation, with the exception of the annular subvalvular aneurysm described in the negro population. Relevant aetiological factors in the development of these post-operative left ventricular pseudoaneurysms are considered. Since pseudoaneurysms are more prone to rupture than true aneurysms, it is concluded that early diagnosis of development of these left ventricular pseudoaneurysms should be made.     

Molecular identification of a novel deltaproteobacterium as the etiologic agent of epizootic bovine abortion (foothill abortion)

Epizootic bovine abortion (EBA) is endemic in California's coastal range and the foothill regions of the Sierra Nevada, where it has been the primary diagnosed cause of abortion in beef cattle for >50 years. Investigation of these losses has defined a specific fetal syndrome characterized by late-term abortion or birth of weak or dead calves. Although the unusual clinical presentation and unique fetal pathology associated with EBA have been recognized since the 1950s, the identity of the etiologic agent is unknown. In this study, suppression-hybridization PCR was used to identify a fragment of the 16S rRNA gene of a previously undescribed bacterium in thymus tissue derived from affected fetuses. Phylogenetic analysis revealed that this pathogen was a deltaproteobacterium closely related to members of the order Myxococcales. A specific PCR was subsequently developed to detect the presence of this bacterium in DNA extracted from fetal thymuses. Using histopathology as the definitive diagnosis for EBA, this PCR demonstrated 100% specificity and 88% sensitivity. The bacterium was also detected in the argasid tick Ornithodoros coriaceus, which is the recognized vector of EBA. These data imply a close association between this novel agent and the etiology of EBA.     

Detection of reticulo-endothelial blockade with low-dose test agent.

Blood clearance and organ extraction of a low-dose reticulo-endothelial test agent, technetium labelled tin colloid (TTC), was measured in groups of rabbits pretreated with reticulo-endothelial blocking agents. Electron microscopy and ultrastructure analysis confirmed that Kupffer cells extracted TTC. Pretreatment with silica caused reduced Kupffer cell uptake and spillover of TTC into the spleen. Pretreatment with sheep red cells caused reduced Kupffer cell uptake and reduced splenic uptake but anti-fibronectin caused only reduced splenic uptake of TTC. TTC is a suitable agent to detect alteration of reticulo-endothelial function.     

An intercomparison of IMRT delivery techniques: a case study for breast treatment

Intensity-modulated radiotherapy beams can be delivered using a multileaf collimator by one of two methods: either by superposition of a series of multiple-static fields, or by moving the collimators while the beam is on to produce 'dynamically' modulated beams. The leaf trajectories in this dynamic mode are given by a series of linear steps between control points defining each collimator position at known intervals throughout an exposure. The complexity of the resulting modulation is limited in the first case by the number of fields superposed and in the second case by the number of control points defined. Results are presented for an experimental study that investigates the effect of changing both the number of fields for the multiple-static technique, and the number of control points for a dynamic 'close-in' technique. All deliveries studied are clinical intensity-modulated breast fields. The effect of using a universal wedge in conjunction with the multileaf collimator is also studied, together with a comparison of the relative efficiency, time taken and the absolute dosimetric accuracy of the various delivery options. It is shown that all delivery techniques produce equivalent dose distributions when using 15 control points, with 10 control points being sufficient to produce an adequate breast compensator distribution. Except for the case of a four-control-point dynamic delivery, the universal wedge makes no significant difference to the dose distribution. However, it makes the delivery less efficient. The close-in interpreter consistently produces deliveries that are more efficient than the more conventional sliding-window technique and faster than the multiple-static-field technique. Finally the close-in technique is compared to the more 'standard' leaf-sweep technique and shown to be equivalent.     

Comparison of the Staph-Ident System with a Conventional Method for Species Identification of Urine and Blood Isolates of Coagulase-Negative Staphylococci

The Staph-Ident system (Analytab Products) for species identification of coagulase-negative staphylococci was compared with the conventional method of Kloos and Schleifer (21). A total of 101 clinical isolates from urine cultures and 95 clinical isolates from blood cultures were studied: overall agreement between the two methods was 86%. We concluded that the Staph-Ident system is a practical test for most clinical microbiology laboratories and that results obtained from this rapid test are comparable to those obtained from the more cumbersome conventional method. Additional investigations are needed to determine the clinical relevance of such species identification.     

A proposal for a standard electronic anthropomorphic phantom for radiotherapy.

To create a database of human male and female computed tomography (CT) slices, the National Library of Medicine organized the "Visible Human Project." Since the male and female data sets provided are approximately 269 MB and 915 MB, respectively, both the size and complexity have been reduced. While making the slices accessible to those with limited computing resources, the production of these reduced data sets also presents a unique opportunity to establish a standard human CT slice library for research in radiation therapy. A brief history of the original data sets is included, as well as details of the reduction process, applications to radiotherapy, and information on accessing these reduced image files.     

Urinary tract toxicity in rats following administration of beta 3-adrenoceptor agonists

ZD7114, [(S)-4-[2-(2-hydroxy-3 phenoxypropylamine)ethoxy]-N-(2-methoxyethyl) phenoxyacetamide], and ZD2079, [(R)-N-(2-[4- (carboxymethyl)phenoxy]ethyl)-N-(beta-hydroxyphenethyl)ammonium chloride], are beta 3-adrenoceptor stimulants with selectivity for brown adipose tissue. ZD7144 is the hydrochloride salt of the S-enantiomer of the racemic amide ZD2079. They were developed as potential novel treatments for obesity and non-insulin-dependent diabetes mellitus. Male and female rats were dosed separately by gavage for a minimum of 28 days with 0, 10, 50, and 500 mg/kg/day of ZD7114 or with 0, 10, 30, and 150 mg/kg/day of ZD2079. Two further groups of male and female rats were dosed with 0 and 500 mg/kg/day of ZD7114 for 28 days and were then allowed a 6-wk, undosed withdrawal period. At high doses, both compounds caused urinary tract toxicity, which primarily affected the distal tubules and collecting ducts of the kidney via tubular necrosis. They also caused ureteric inflammation, cystitis, and accumulation of crystalline inclusions throughout the urinary tract. As a result of urinary tract toxicity, affected animals from one or both studies showed reduced red blood cell indices, lower platelet counts, and higher white cell counts. Blood chemistry revealed lower plasma concentrations of glucose (7.28 +/- 1.37 compared to 8.11 +/- 0.65 for the control) and total protein (63.42 +/- 3.65 compared to 69.17 +/- 3.24 for the control) and increased plasma urea (37.15 +/- 19.96 compared to 8.09 +/- 0.87 for the control). Urinalysis showed an increase in the number of crystals, blood, and protein. In the urinary tract, the severe crystalluria with accumulation of crystalline material indicated that this may have a role in the etiology of the target organ toxicity. Poor solubility of the compounds at normal urinary pH was considered a possible mechanism for the crystalluria.