Pollutant dispersion in a large indoor space: Part 1 -- Scaled experiments using a water-filled model with occupants and furniture

Scale modeling is a useful tool for analyzing complex indoor spaces. Scale model experiments can reduce experimental costs, improve control of flow and temperature conditions, and provide a practical method for pretesting full-scale system modifications. However, changes in physical scale and working fluid (air or water) can complicate interpretation of the equivalent effects in the full-scale structure. This paper presents a detailed scaling analysis of a water tank experiment designed to model a large indoor space, and experimental results obtained with this model to assess the influence of furniture and people in the pollutant concentration field at breathing height. Theoretical calculations are derived for predicting the effects from losses of molecular diffusion, small scale eddies, turbulent kinetic energy, and turbulent mass diffusivity in a scale model, even without Reynolds number matching. Pollutant dispersion experiments were performed in a water-filled 30:1 scale model of a large room, using uranine dye injected continuously from a small point source. Pollutant concentrations were measured in a plane, using laser-induced fluorescence techniques, for three interior configurations: unobstructed, table-like obstructions, and table-like and figure-like obstructions. Concentrations within the measurement plane varied by more than an order of magnitude, even after the concentration field was fully developed. Objects in the model interior had a significant effect on both the concentration field and fluctuation intensity in the measurement plane. PRACTICAL IMPLICATION: This scale model study demonstrates both the utility of scale models for investigating dispersion in indoor environments and the significant impact of turbulence created by furnishings and people on pollutant transport from floor level sources. In a room with no furniture or occupants, the average concentration can vary by about a factor of 3 across the room. Adding furniture and occupants can increase this spatial variation by another factor of 3.

Angiogenesis mediated by metabolites is dependent on vascular endothelial growth factor (VEGF)

Metabolites released from hypoxic tissues have recently been reported to be angiogenic, although it remains to be clarified if they have a role independent of the upregulation of hypoxia-inducible genes such as vascular endothelial growth factor (VEGF). In an attempt to conclusively evaluate their role, the metabolites lactate, pyruvate, malate and adenosine were tested in a two-dimensional in vitro angiogenesis assay which consists of human umbilical vein endothelial cells (HUVECs) co-cultured with fibroblasts of dermal origin. In addition, ethanol was tested. Metabolism of ethanol leads to increased levels of lactate and malate, which may explain its recently reported angiogenic properties. Lactate, malate, adenosine and ethanol produced a significant angiogenic response, although this was only observed at certain concentrations. However this angiogenic response was abolished when repeated in the presence of neutralising anti-VEGF antibodies. The results of this study therefore indicate that the angiogenic potential of metabolites is dependent upon increased expression of VEGF.

Surface modification of a segmented polyetherurethane using a low-powered gas plasma and its influence on the activation of the coagulation system

A medical grade segmented polyetherurethane (PEU) was treated with a low-powered gas plasma using O(2), Ar, N(2) and NH(3) as the treatment gases. Changes in the surface functional group chemistry were studied using X-ray photoelectron spectroscopy. The wettability of the surfaces was examined using dynamic contact angle measurements and the surface morphology was evaluated using atomic force microscopy. The influence of the surface modification to the polyurethane on the blood response to the polyetherurethane was investigated by measuring changes in the activation of the contact phase activation of the intrinsic coagulation cascade. The data demonstrate that the plasma treatment process caused surface modifications to the PEU that in all cases increased the polar nature of the surfaces. O(2) and Ar plasmas resulted in the incorporation of oxygen-containing groups that remained present following storage in an aqueous environment. N(2) and NH(3) plasmas resulted in the incorporation of nitrogen-containing groups but these were replaced with oxygen-containing groups following storage in the aqueous environment. In all plasma treatments there was a lowering of contact phase activation compared to the untreated surface, the N(2) and NH(3) treatments dramatically so.

Subungual melanoma with osteocartilaginous differentiation

Osteocartilaginous metaplasia is known to occur rarely in melanomas, particularly in subungual melanomas. We present a case of a calcified subungual soft tissue tumour in which biopsy of the lesion showed malignant round and spindle-shaped tumour cells, many of which were associated with the formation of cartilage and osteoid-like material. Subsequent resection showed clear histological evidence of a subungual melanoma. Tumour cells expressed S100, melan-A and neurone-specific enolase but were negative for HMB45. Diagnostic radiological and histological features and the nature of the osteocartilaginous differentiation within this lesion is discussed.

Staurosporine-induced apoptosis and hydrogen peroxide-induced necrosis in two human breast cell lines

The use of apoptosis-inducing agents in the treatment of malignant cancer is increasingly being considered as a therapeutic approach. In this study, the induction of apoptosis and necrosis was examined in terms of temporal dose responses, comparing a malignant and nonmalignant breast cell line. Staurosporine (SSP)-induced apoptosis and H(2)O(2)-induced necrosis were evaluated by two cytotoxicity assays, neutral red (NR) and methyl-thiazolyl tertrazolium (MTT), in comparison with a differential dye uptake assay, using Hoechst33342/propidium iodide (Hoechst/PI). Confirmatory morphological assessment was also performed by routine resin histology and transmission electron microscopy. Cell viability was assessed over a 0.5-48 h time course. In nonmalignant HBL-100 cells, 50 nM SSP induced 100% apoptosis after a 48 h exposure, while the same exposure to SSP caused only 4% apoptosis in metastatic T47D cells. Although complete apoptosis of both cell lines was induced by 50 microM SSP, this effect was delayed in T47D (24 h) compared with HBL-100 (4 h). Results also showed that neither MTT or NR can distinguish between the modes of cell death, nor detect the early onset of apoptosis revealed by Hoechst/PI.

A study of metabolites as intermediate effectors in angiogenesis

Metabolites released from hypoxic tissues have been reported as angiogenic factors in circumstances of reduced tissue oxygenation or an increased rate of metabolism. However, in more recent reports their possible role in angiogenesis prior to the induction of hypoxia-inducible genes appears to have been neglected. In a systematic attempt to evalaute their role, metabolites common to the glycolytic and oxidative pathways (nicotinamide adenine dinucleotide, adenosine diphosphate and adenosine triphosphate), exclusively glycolytic metabolites (pyruvate and lactic acid) and exclusively oxidative metabolites (malate, succinate, fumarate and citrate) were tested to assess their effects upon in vivo angiogenesis and in vitro endothelial cell migration and proliferation. In addition, adenosine was tested due to its proposed role in hypoxia-induced angiogenesis. The angiogenic effects in vivo were examined using the chick chorioallantoic membrane assay and in vitro on chick embryonic capillary endothelial cells using a phagokinetic track/migration assay and crystal violet dye binding/proliferation assay. Metabolites common to the glycolytic and oxidative metabolic pathways and exclusively glycolytic metabolites produced an angiogenic response in vivo and in vitro on endothelial cell proliferation and migration, whereas exclusively oxidative metabolites, with the exception of malate, did not. Adenosine caused an increased proliferation of blood vessels in vivo and stimulated endothelial cell migration and proliferation. Overall, these results implicate metabolites as effectors in angiogenesis and it is proposed that they have a role which is possibly independent of the upregulation of hypoxia-inducible genes.

Dense nonaqueous phase liquid tracer tests: experimental results

Two dense nonaqueous phase liquid (DNAPL) tracer tests were carried out in a shallow aquifer north of Fort Worth, TX. i-Propanol was used as the nonpartitioning tracer: n-hexanol and n-octanol were the partitioning tracers. Field data, mathematical modeling, the results of column tests, and field tracer tests with NaCl were used in designing the DNAPL tracer tests. The results indicated the presence of DNAPL at both sites tested; semi-quantitative estimates of the amounts of DNAPL present were obtained by mathematical modeling. Interpretation was complicated by heterogeneity of the aquifer and mass transport effects.

Limited magnetic resonance imaging in low back pain instead of plain radiographs: experience with first 1000 cases

AIM

We report our experience with the first 1000 patients with non-traumatic low back pain (LBP) without radiculopathy undergoing limited sequence magnetic resonance imaging (MRI) instead of plain radiography.

METHODS

Between January 1996 and December 1998, 1042 patients with low back pain unresponsive to conservative treatment were examined using a limited MR protocol comprising sagittal T1-weighted and STIR imaging. Plain radiographs were not performed.

RESULTS

Malignancy, infection, vertebral fracture, spondylitis, pars defects and cord tumours were detected in 20%. Of the 82 osteoporotic vertebral fractures detected, 51 (62%) were recent and 31 had normal marrow signal indicating that they were old. Eighty pars defects were identified, 45(56%) had spondylolisthesis, 29(37%) were undisplaced and 6 (7%) had pars oedema only. Neoplastic disease was found in 17(8%) of which none was suspected before imaging. Benign neoplastic diseases such as vertebral AVM/haemangiomata were excluded. Twenty-one patients had a variety of disorders including ankylosing spondylitis (7), large vessel aneurysm (3), discitis (2), ovarian cyst (2), sequestered disc (2), sacral insufficiency fracture (2) and one patient each with burst fracture, retroperitoneal haematoma and a previously unsuspected horseshoe kidney.

CONCLUSION

The majority of patients with LBP are best assessed clinically and imaging is usually not required. In patients with worrying symptoms, MRI with a limited protocol detects a greater number of abnormalities than previously reported studies using plain radiographs and has replaced plain radiography in our hospital. We report our experience with the first 1000 patients and highlight issues such as protocols, detection rates and communication issues.

Ultrasound of the shoulder

Ultrasound of the shoulder is a powerful and accurate method for the examination of the rotator cuff, biceps mechanism and the synovium. This article describes the anatomy, standard examination technique, indications, pitfalls and potential errors. It lists suggested imaging algorithms for a range of shoulder pathology.

Multiple intestinal 'loops' provide an in vivo model to analyse multiple mucosal immune responses

Mucosal immunity plays an important role in preventing disease but the induction of protective mucosal immune responses remains a significant challenge. We describe a novel in vivo model to analyze the induction of multiple mucosal immune responses in the small intestine. A sterile segment of intestine ('intestinal-segment'; 2-3 m long) was surgically prepared in the jejunum of 4-6-month-old lambs. This 'intestinal-segment' was then subdivided into consecutive segments, designated as 'loops' (15-20 cm long), that included a Peyer's patch (PP), or 'interspaces' (15-70 cm long), that lacked a visible PP. All 'loops' were sterile when collected 1-4 weeks post-surgery and there was no macroscopic or histological evidence of altered lymph or blood flow. Flow cytometric analysis of cells isolated from PP, mucosal epithelium (IEL) and the lamina propria (LPL) revealed no significant alterations in the cell populations present in 'loop' tissues. The functional integrity of M-cell antigen uptake in sterile intestinal 'loops' was evaluated by comparing the immune response induced by varying doses of soluble versus particulate porcine serum albumin (PSA formulated in alginate microspheres). A dose-dependent, PSA-specific antibody-secreting cell response was restricted to PP present in 'loops' injected with particulate PSA. These observations suggested that PP present in sterile 'loops' were functional and this conclusion was confirmed by detecting cholera toxin-specific antibody-secreting cells and secreted antibody in PP and intestinal contents, respectively, of immunized 'loops.' Thus, each 'loop' provided an independent site to analyze antigen-uptake and the induction of mucosal immune responses by a variety of antigen or vaccine formulations.

A structural role for tryptophan 188 of inducible nitric oxide synthase

All nitric oxide synthase (NOS) isotypes bear a conserved tryptophan that stacks against the proximal face of the heme cofactor. Recently two hyperactive variants of neuronal NOS were reported in which this residue (W409) was replaced by phenylalanine or tyrosine. We find that mutation of the same residue in the oxygenase domain of inducible NOS (W188) to phenylalanine causes severe destabilization of heme binding. W188F is isolated in a predominantly heme-free state, and axial thiolate ligation to the residual bound heme is unstable. However, W188F is soluble and is expressed at levels comparable to wild type. While circular dichroism spectroscopy demonstrates the loss of some secondary structure, the protein chain is not completely denatured and it retains much of its fold between pH 7.5 and 4. This proximal tryptophan of NOS represents a case where a residue is conserved within an enzyme family but for distinct purposes that are isotype-dependent.

Enhancement of human osteoblast proliferation and phenotypic expression when cultured in human serum

Traditionally, culture medium is supplemented with foetal bovine serum (FBS). However, in cultures of osteoblasts intended for human re-implantation, such serum presents potential risks of foreign protein contamination and transmission of viral or prion-related material, if used. We cultured human osteoblasts from 16 patients in 10% autologous human serum, 10% pooled human serum, 10% FBS or 2% Ultroser G. Non-synthetic sera were tested in both heat-treated and non-heat-treated forms. We determined cell growth and osteoblast phenotype. Cell proliferation in all types of human serum was significantly greater than in FBS. This was most marked in heat-treated autologous human serum. Cells cultured in Ultroser G had less proliferation than all other groups. The phenotypic tests showed that cells cultured in human and foetal bovine serum displayed an osteoblast phenotype, with greater protein expression in cells cultured in human serum. We conclude that culture of human osteoblasts in autologous human serum enhances cell proliferation, while maintaining an osteoblast phenotype. These findings have implications for the use of cultured osteoblasts in self-cell therapy. Human osteoblast growth is supported by autologous human serum, which allows re-implantation of cultured cells, while avoiding the risk of foreign protein carry-over with enhancement of cell proliferation.

Identification of differentially expressed genes in hepatocellular carcinoma and metastatic liver tumors by oligonucleotide expression profiling

BACKGROUND

The characterization of differentially expressed genes between cancerous and normal tissues is an important step in the understanding of tumorigenesis. Global gene expression profiling with microarrays has now offered a powerful tool to measure the changes of thousands of genes in any carcinoma tissues in an effort to identify these key disease-related genes. To compare the gene expression of a primary liver carcinoma, metastatic carcinoma to the liver, and normal liver, the authors analyzed tissue from six primary hepatocellular carcinomas (HCCs), five colorectal adenocarcinoma metastases to the liver, and eight normal livers.

METHODS

Samples were processed from total RNA to fragmented cRNA and hybridized onto Affymetrix GeneChip(R) expression arrays. Analyses were performed to determine the consensus pattern of gene expression for primary liver carcinoma, metastatic liver carcinoma, and normal liver tissue and their changes in expression level.

RESULTS

In hepatocellular carcinoma, 842 genes were overexpressed, and 393 genes were underexpressed in comparison with genes of normal liver tissue. Of note, 7 of the 20 most increased identified known genes previously have been associated with liver carcinoma or other types of cancers. The 13 additional identified genes until now have not previously shown strong association with cancers. Furthermore, the authors identified 42 genes and 24 expressed sequence tags that are expressed at a significant level in both HCC and metastastic tumors, presenting a list of marker genes indicative of cancerous liver tissue.

CONCLUSIONS

In this study, genes that can be involved in the production of and maintenance of hepatic carcinomas were identified. These data offer new insight into genes that are potentially important in the pathogenesis of liver carcinoma, as well as additional targets for new strategies for cancer therapy and treatment.

Primary Ewing sarcoma of the orbit

PURPOSE

To report the clinicopathologic features of a 17-year-old patient with primary Ewing sarcoma of the orbit.

METHODS

The patient was evaluated clinically before surgery with computed tomography scans of the orbit. After surgery, the patient was staged with computed tomography scans and bone scan and was treated with systemic chemotherapy and radiation therapy to the orbit. The orbital biopsy was evaluated with conventional light microscopy and immunohistochemistry.

RESULTS

Clinical evaluation revealed proptosis and limited upgaze. Computed tomography scans disclosed a mass involving the superior orbit, anterior cranial fossa, and temporal fossa. Microscopic examination revealed small, poorly differentiated cells with medium-sized nuclei containing finely granular chromatin and small nucleoli. The cytoplasmic borders of the cells were indistinct. A PAS stain revealed modest glycogen in many of the tumor cells. The tumor stained positive for O-13 and vimentin and was negative for neural, skeletal, and lymphoid cell markers. Computed tomography scan, bone scan, and blood chemistries revealed no other site of involvement. After treatment, the clinical symptoms and signs resolved, and there has been no evidence of residual orbital tumor or metastasis.

CONCLUSIONS

Primary Ewing sarcoma of the orbit should be considered in the differential diagnosis of children or young adults with proptosis, diplopia, or periorbital swelling. Immunohistochemistry is essential to distinguish Ewing sarcoma from other small round cell tumors.

Characterization and analysis of the PikD regulatory factor in the pikromycin biosynthetic pathway of Streptomyces venezuelae

The Streptomyces venezuelae pikD gene from the pikromycin biosynthetic cluster was analyzed, and its deduced product (PikD) was found to have amino acid sequence homology with a small family of bacterial regulatory proteins. Database comparisons revealed two hypothetical domains, including an N-terminal triphosphate-binding domain and a C-terminal helix-turn-helix DNA-binding motif. Analysis of PikD was initiated by deletion of the corresponding gene (pikD) from the chromosome of S. venezuelae, resulting in complete loss of antibiotic production. Complementation by a plasmid carrying pikD restored macrolide biosynthesis, demonstrating that PikD is a positive regulator. Mutations were made in the predicted nucleotide triphosphate-binding domain, confirming the active-site amino acid residues of the Walker A and B motifs. Feeding of macrolide intermediates was carried out to gauge the points of operon control by PikD. Although the pikD mutant strain was unable to convert macrolactones (10-deoxymethynolide and narbonolide) to glycosylated products, macrolide intermediates (YC-17 and narbomycin) were hydroxylated with high efficiency. To study further the control of biosynthesis, presumed promoter regions from pik cluster loci were linked to the xylE reporter and placed in S. venezuelae wild-type and pikD mutant strains. This analysis demonstrated that PikD-mediated transcriptional regulation occurs at promoters controlling expression of pikRII, pikAI, and desI but not those controlling pikRI or pikC.

Clinicopathologic correlation of fluorescein and indocyanine green angiography in exudative age-related macular degeneration

PURPOSE

To correlate the clinical and histopathologic features of an eye with age-related macular degeneration studied with fluorescein (FA) and indocyanine green (ICG) angiography 4.5 months before the patient's death.

METHODS

Histopathologic features from serial sections through the macula of a 76-year-old man with occult choroidal neovascularization (CNV) were reconstructed in a scaled two-dimensional map and compared with FA and ICG angiogram images obtained 4.5 months before his death.

RESULTS

The region of prior laser photocoagulation was identified as a well-demarcated hypofluorescent region in the early frames of the FA and the early and late phases of the ICG angiogram. This corresponded histopathologically to a well-circumscribed area of absence of the choriocapillaris, loss of the outer retina and retinal pigment epithelium, and scarring of the choroid. Occult CNV characterized by elevated late hyperfluorescence on the FA and intense well-defined hyperfluorescence on the ICG angiogram corresponded to a thick fibrovascular membrane in the subretinal space and within Bruch's membrane. Thin extensions of both the subretinal and intra-Bruch's membrane fibrovascular membrane components corresponded to nonelevated stippled late hyperfluorescence on the FA and mild late hyperfluorescence on the ICG angiogram.

CONCLUSION

Histopathologic mapping revealed a large fibrovascular complex located subretinally and within Bruch's membrane with thin and thick components that correlate well with findings of occult CNV on FA and ICG angiography.

Outbreaks of clinical mastitis caused by Trichosporon beigelii in dairy herds

Trichosporon beigelii is widely distributed in nature and is classically associated with white piedra, a mycosis that may involve the hair of the human body. Intramammary infections caused by T beigelii may be fatal in cows; the prevalence in affected dairy herds may be high. Affected cows may have hyperthermia, swelling of the udder, and substantially decreased milk production or agalactia. Intramammary infections caused by yeast, including T beigelii, may also be associated with high bacterial counts in bulk-tank milk.

Radiological review of accident and emergency radiographs: a 1-year audit

AIM

To assess the impact and cost effectiveness of a system of radiological review of accident and emergency (A&E) plain films.

MATERIALS AND METHODS

Review documentation was studied retrospectively over a 1-year period. Six hundred and eighty-four actual or suspected errors in the initial radiological interpretation by A&E staff were highlighted by radiologists in training. These selected 'red reports' were then further reviewed by a musculoskeletal radiologist and a more senior member of the A&E team.

RESULTS

Three hundred and fifty-one missed or strongly suspected fractures were detected, with ankle, finger and elbow lesions predominating. Other errors included 11 missed chest radiograph abnormalities and 24 A&E false-positives. Radiologists in training tended to over-report abnormalities with an 18% false-positive rate when compared to the subsequent musculoskeletal radiology opinion. Following review, further action was taken by A&E staff in 286 (42.6%) of cases. No operative intervention was required in those patients with a delayed or missed A&E diagnosis. Consideration is given to the cost of providing this form of review and the impact of medico-legal factors.

CONCLUSION

Compared with the large numbers of patients seen and radiographed in a busy A&E department, the number of radiological errors was small. There were even fewer changes in management. Despite this, concern over litigation, clinical governance and future work patterns in A&E make this form of review a useful means of risk reduction in a teaching hospital.Williams, S. M. (2000). Clinical Radiology55, 861-865

Ability of anaesthetists to identify a marked lumbar interspace

Anaesthetists' ability to identify correctly a marked lumbar interspace was assessed in 100 patients undergoing spinal magnetic resonance imaging scans. Using ink, one anaesthetist marked an interspace on the lower spine and attempted to identify its level with the patient in the sitting position. A second anaesthetist attempted to identify the level with the patient in the flexed lateral position. A marker capsule was taped over the ink mark and a routine scan performed. The actual level of markers ranged from one space below to four spaces above the level at which the anaesthetist believed it to be. The marker was one space higher than assumed in 51% of cases and was identified correctly in only 29%. Accuracy was unaffected by patient position (sitting or lateral), although it was impaired by obesity (p = 0.001) and positioning of the markers high on the lower back (p < 0.001). The spinal cord terminated below L(1) in 19% of patients. This, together with the risk of accidentally selecting a higher interspace than intended for intrathecal injection, implies that spinal cord trauma is more likely when higher interspaces are selected.