Chondroma of the mandibular condyle: an example of a rare tumour

Chondromas are benign tumours of cartilage which are rare in the head and neck. We present a case report of a chondroma in the neck of condyle and demonstrate the value of multiplanar spiral CT and the limitations of 3D reconstruction.     

Exceptionally high seizure threshold: ECT device limitations

Numerous studies have confirmed the distinct biological behavior of two subsets of prostate cancer diagnosed incidentally after either transurethral resection (TURP) or open prostatectomy for presumed benign prostatic hyperplasia (BPH). Focal, low-grade lesions are associated with a low risk for clinical progression and are designated as stage T1a or A1. These cases have traditionally been managed conservatively with close clinical observation. In contrast, multifocal, high-volume, or high-grade tumors are associated with a more aggressive clinical course and are designated as stage T1b or A2. Early definitive intervention is usually advocated for these latter patients. Therefore, accurate pathological assignment to either stage T1a or T1b is crucial for selection of appropriate management options. A variety of methods for staging patients with incidentally detected prostate cancer have been proposed, including detailed histological analysis, repeat TURP or transurethral biopsy, serial prostate-specific antigen (PSA) analysis, and imaging with either transrectal ultrasound (TRUS) or magnetic resonance (MRI) techniques. This article critically examines the clinical utility of these staging modalities for patients with incidentally detected prostate cancer.     

Muscle mass and fat mass in relation to bone mineral density in very old men and women: the Framingham Heart Study

Aim of the study was investigate the cross-sectional relationship between body composition and bone mineral density (BMD) in very old men and women. The study sample consisted of 504 women and 285 men, aged 72-93 yr, participating in examination 22 (1992-1993) of the Framingham Heart Study. Total body BMD, regional BMD, and soft-tissue body composition was measured by dual-energy X-ray absorptiometry. Both muscle mass and percentage body fat were positively associated with total body BMD in women. After adjustment for age, physical activity, smoking status, estrogen use, and thiazide use, BMD increased with increasing tertile of muscle mass (p = 0.007) and with increasing tertile of percentage body fat (p = 0.0001) in women. In men muscle mass, not percentage body fat, was positively associated with BMD. After adjustment for potential confounders, BMD remained associated with muscle mass only (p = 0.02). These results were similar for leg BMD and arm BMD. The study suggests that the influence of muscle and fat mass on bone mineral density is different between very old men and women.     

Participation as a complicating mechanism: the effect of clinical professional and middle manager participation on hospital performance

One way hospitals complicate themselves is by increasing the participation of clinical professionals and middle managers in making strategic decisions. Using a survey methodology this article investigates the relationships between the participation of clinical professionals (MDs and RNs) and middle managers with hospital costs, as well as the possible moderating effect of strategic complexity.     

Human wound contraction: collagen organization, fibroblasts, and myofibroblasts

The closure of ungrafted sacrococcygeal pilonidal sinus excisional wounds was studied in 15 patients. Wound punch biopsies were taken on a regular basis, and histologic sections were made. To document changes, computer-assisted morphometric image analysis was employed. Initial average wound depth was 37.8 +/- 4.6 mm, and complete closure (0 wound depth) was reached by 68 days. Wound contraction contributed 88 percent to wound closure, whereas the deposition of scar only contributed 12 percent. Maximum cells density within granulation tissue was reached by day 18. Myofibroblasts, identified by alpha-smooth muscle actin immunostaining, first appeared on day 11. Unlike those observed in laboratory animals, myofibroblasts were a minor cell population of granulation tissue, never exceeding 10 percent of the cells. The pattern of collagen fiber organization was documented by polarized light microscopy of Sirius red-stained sections. Early granulation tissue collagen fibers demonstrated a fine greenish birefringence, whereas more mature granulation tissue collagen fibers were thicker, displaying orange-yellowish birefringence. Myofibroblasts were associated exclusively with thicker collagen fibers, whereas fibroblasts were associated with both fine and thick collagen fibers. It is proposed that human wound contraction involves a volume change whereby normal dermal and adipose tissues are pulled into the defect by forces generated within fibroblasts.     

Production of human normal adult and fetal hemoglobins in Escherichia coli

A hemoglobin expression system in Escherichia coli is described. In order to produce authentic human hemoglobin, we need to co-express both methionine aminopeptidase and globin genes under the control of a strong promoter. We have constructed three plasmids, pHE2, pHE4 and pHE7, for the expression of human normal adult hemoglobin and a plasmid, pHE9, for the expression of human fetal hemoglobin, in high yields. The globin genes can be derived from either synthetic genes or human globin cDNAs. The extra amino-terminal methionine residues of the expressed globins can be removed by the co-expressed methionine aminopeptidase. The heme is inserted correctly into the expressed alpha- globin from our expression plasmids. A fraction (approximately 25%) of the heme is not inserted correctly into the expressed beta- or gamma- globin. However, the incorrectly inserted hemes can be converted into the correct conformation by carrying out a simple oxidation-reduction process on the purified hemoglobin molecule. We have investigated the functional properties of the expressed hemoglobins by measuring their oxygen-binding properties and their structural features by obtaining their 1H-NMR spectra. Our results show that authentic human normal adult and fetal hemoglobins can be produced from our expression plasmids in E. coli and in high yields. Our expression system allows us to design and to produce any recombinant hemoglobins needed for our research on the structure-function relationship in hemoglobin.      

Modeling drop breakage using the full energy spectrum and a specific realization of turbulence anisotropy

The assumption of homogeneous isotropic turbulence when modeling drop breakage in industrially relevant geometries is questionable. We describe the development of an anisotropic breakage model, where the anisotropy is introduced via the inclusion of a perturbed turbulence spectrum. The selection of the perturbed spectrum is itself motivated by our previous large-eddy simulations of high-pressure homogenizers. The model redistributes energy from small to large scales, and assumes that the anisotropic part of the Reynolds stresses is confined to the energy-containing range. The second-order structure function arising from the perturbed spectrum is used in the standard framework of Coulaloglou and Tavlarides to calculate breakage frequency. While the base model exhibits non-monotonic behavior (by predicting a maximum value for a certain drop size), the effect of anisotropy is shown to increase breakage frequency in length scales larger than this peak, thereby reducing non-monotonicity. This effect is more pronounced for small turbulence Reynolds numbers.     

Restoration of stormwater retention capacity at the allotment-scale through a novel economic instrument

Urbanisation results in changes to runoff behaviour which, if not addressed, inevitably degrade receiving waters. To date, most stormwater management has focussed on the streetscape and public open space. Given that much of the catchment imperviousness is located on private land, we developed and tested a novel economic instrument (a uniform price auction) for encouraging allotment-scale stormwater retention. We evaluated bids using an integrated environmental benefit index (EBI), based on the ability of the proposed works to reduce runoff frequency, pollutant loads and to reduce potable water demand. The uniform price auction resulted in 1.4 ha of impervious areas being effectively 'disconnected' from the stormwater system. The EBI provided an objective and transparent method of comparing bids, which varied in the type of works proposed (e.g. rainwater tank, rain-garden), the cost and the resulting environmental benefit. Whilst the pilot auction was a success, the public subsidy of works undertaken was around 85%, meaning that property owners a relatively small private benefit in the works. Future auction rounds will be revised to (i) test an EBI which is more focussed on the protection of streams (assessing changes to runoff frequency, baseflow volumes and water quality) and (ii) provide an auction process which is simpler to understand, and provides greater practical support for landholders who wish to undertake works.