Efficacy of green infrastructure in reducing exposure to local, traffic-related sources of airborne particulate matter (PM).

One aim of roadside green infrastructure (GI) is to mitigate exposure to local, traffic-generated pollutants. Here, we determine the efficacy of roadside GI in improving local air quality through the deposition and/or dispersion of airborne particulate matter (PM). PM was collected on both pumped air filters and on the leaves of a recently installed 'tredge' (trees managed as a head-high hedge) at an open road environment next to a primary school in Manchester, U.K. The magnetic properties of PM deposited on leaves and filters (size fractions PM10 and PM2.5) were deduced from hysteresis loops, first-order reversal curves (FORCs), and low-temperature remanence measurements. These were complemented with electron microscopy to identify changes in magnetic PM concentration downwind of the tredge/GI. We show that the tredge is permeable to airflow using a simple CO2 tracer experiment; hence, it allows interception and subsequent deposition of PM on its leaves. Magnetic loadings per m3 of air from filters (PM10 saturation magnetisation, Ms, at 5 K) were reduced by 40 % behind the tredge and a further 63 % in the playground; a total reduction of 78 % compared to roadside air. For the PM2.5 fraction, the reduction in magnetic loading behind the tredge was remarkable (82 %), reflecting efficient diffusional capture of sub-5 nm Fe-oxide particles by the tredge. Some direct mixing of roadside and playground air occurs at the back of the playground, caused by air flow over, and/or through gaps in, the slowly-permeable tredge. The magnetic loading on tredge leaves increased over successive days, capturing ~23 % of local, traffic-derived PM10. Using a heuristic two-dimensional turbulent mixing model, we assess the limited dispersion of PM < 22.5 µm induced by eddies in the tredge wake. This study demonstrates that PM deposition on leaves reduces exposure significantly in this school playground setting; hence, providing a cost-effective mitigation strategy.

Magnetic and microscopic investigation of airborne iron oxide nanoparticles in the London Underground.

Particulate matter (PM) concentration levels in the London Underground (LU) are higher than London background levels and beyond World Health Organization (WHO) defined limits. Wheel, track, and brake abrasion are the primary sources of particulate matter, producing predominantly Fe-rich particles that make the LU microenvironment particularly well suited to study using environmental magnetism. Here we combine magnetic properties, high-resolution electron microscopy, and electron tomography to characterize the structure, chemistry, and morphometric properties of LU particles in three dimensions with nanoscale resolution. Our findings show that LU PM is dominated by 5-500 nm particles of maghemite, occurring as 0.1-2 µm aggregated clusters, skewing the size-fractioned concentration of PM artificially to larger sizes when measured with traditional monitors. Magnetic properties are largely independent of the PM filter size (PM10, PM4, and PM2.5), and demonstrate the presence of superparamagnetic (< 30 nm), single-domain (30-70 nm), and vortex/pseudo-single domain (70-700 nm) signals only (i.e., no multi-domain particles > 1 µm). The oxidized nature of the particles suggests that PM exposure in the LU is dominated by resuspension of aged dust particles relative to freshly abraded, metallic particles from the wheel/track/brake system, suggesting that periodic removal of accumulated dust from underground tunnels might provide a cost-effective strategy for reducing exposure. The abundance of ultrafine particles identified here could have particularly adverse health impacts as their smaller size makes it possible to pass from lungs to the blood stream. Magnetic methods are shown to provide an accurate assessment of ultrafine PM characteristics, providing a robust route to monitoring, and potentially mitigating this hazard.

Epigenetic mechanisms of tumorigenicity manifesting in stem cells.

One of the biggest roadblocks to using stem cells as the basis for regenerative medicine therapies is the tumorigenicity of stem cells. Unfortunately, the unique abilities of stem cells to self-renew and differentiate into a variety of cell types are also mechanistically linked to their tumorigenic behaviors. Understanding the mechanisms underlying the close relationship between stem cells and cancer cells has therefore become a primary goal in the field. In addition, knowledge gained from investigating the striking parallels between mechanisms orchestrating normal embryogenesis and those that invoke tumorigenesis may well serve as the foundation for developing novel cancer treatments. Emerging discoveries have demonstrated that epigenetic regulatory machinery has important roles in normal stem cell functions, cancer development and cancer stem cell (CSC) identity. These studies provide valuable insights into both the shared and distinct mechanisms by which pluripotency and oncogenicity are established and regulated. In this review, the cancer-related epigenetic mechanisms found in pluripotent stem cells and cancer cells will be discussed, focusing on both the similarities and the differences.

Central neurilemmoma of the jaw in concurrence with radicular cyst: a case report.

We report the features of a central neurilemmoma in the mandible of a patient having an inflammatory apical dental (radicular) cyst in the same region. A 29-year-old woman complained of numbness on the right side of the lower lip of 3 months duration and noted following endodontic therapy to the right mandibular first molar tooth. Panoramic radiography revealed a bilocular radiolucency in the right body of the mandible. Excisional biopsy was performed. The histopathology revealed neurilemmoma of the mandible in concurrence with inflammatory apical dental (radicular) cyst. No recurrence was detected during a 1-year follow-up.

Effects of weight bearing and non-weight bearing exercises on bone properties using calcaneal quantitative ultrasound.

OBJECTIVE: This study was designed to investigate bone properties using heel quantitative ultrasound (QUS) in young adults participating in various sports. METHODS: A cross sectional study was performed on Chinese male students (n = 55), aged 18-22 years. Subjects with previous fractures or suffering from any diseases known to affect bone metabolism or taking any medication with such an effect, were not included. The subjects were categorised according to their main sporting activities, including soccer (n = 15) (a high impact, weight bearing exercise), dancing (n = 10) (a low impact, weight bearing exercise), and swimming (n = 15) (non-weight bearing exercise). A sedentary group acted as controls (n = 15). A reproducibility study of the velocity of sound (VOS) and the broadband ultrasound attenuation (BUA) measurement was performed and analysed using the intraclass correlation coefficient (ICC). RESULTS: There was good intra-investigator and inter-investigator agreement (ICC > or = 0.8; p < 0.05) in the measurement of BUA and VOS. No significant differences in BUA and VOS (p > 0.05) were found between the dominant and non-dominant heel. Soccer players (137 +/- 4.3 dB/MHz; 1575 +/- 56 m/s; 544.1 +/- 48.4) and dancers (134.6 +/- 3.7 dB/MHz; 1538 +/- 46 m/s; 503.0 +/- 37.0) had significantly higher BUA, VOS, and stiffness index (SI) scores (p < 0.05), respectively, than swimmers (124.1 +/- 5.1 dB/MHz; 1495 +/- 42 m/s; 423.3 +/- 46.9) and the sedentary control group (119.9 +/- 6.1 dB/MHz; 1452 +/- 41 m/s; 369.9 +/- 46.4). A trend of a significant linear increase with the weight bearing and high impact exercise was revealed in all QUS parameters (p < 0.05). CONCLUSION: This cross sectional study indicated that regular participation in weight bearing exercise in young people might be beneficial for accruing peak bone mass and optimising bone structure.

Hair-thread tourniquet syndrome.

We report a case of hair-thread tourniquet syndrome involving the labia majora of a 14-year-old autistic child. 'Hair-thread tourniquet' refers to the process whereby a thread of hair leads to the ischaemic strangulation of an appendage or other piece of tissue. Uncommonly recognized, this syndrome has gradually gained recognition since its first description in 1612. As it remains infrequent, many have attributed its aetiology to abuse or socio-cultural practices. We review the published literature on this infrequent but important paediatric condition.

Laparoscopic transperitoneal clipping of the inferior mesenteric artery for the management of type II endoleak after endovascular repair of an aneurysm.

We report the case of a high risk patient with an abdominal infrarenal aortic aneurysm (AAA) who was treated by endovascular technique and the subsequent management of a type II endoleak by the laparoscopic approach. In this case, a 74-year-old woman with a 6-cm infrarenal AAA underwent endovascular repair using a bifurcated stent-graft device. Surveillance CT scan showed a persistent type II endoleak at 1 week and 3 months after the operation. Angiography confirmed retrograde flow from the inferior mesenteric artery (IMA). Attempted transarterial embolization of the IMA via the superior mesenteric artery was not successful. Laparoscopic transperitoneal IMA clipping was performed. Subsequent aortic duplex scan and CT scan confirmed complete elimination of the type II endoleak. We conclude that a combination of endovascular and laparoscopic procedures can be used to manage AAA successfully.

Quality of life in patients with chronic anal fissure.

OBJECTIVE: Little is known about the quality of life in patients with the distressing symptoms of chronic anal fissure. This was a prospective study assessing the physical and mental health of fissure patients before and after topical treatment. PATIENTS AND METHODS: New patients attending the fissure clinic were recruited prospectively into the study over a 2-month period. On first appointment, patients were given 2 questionnaires to complete: the Short-Form 36 Health Survey (SF-36) and a general questionnaire recording patients' demographic details, previous treatment, site and duration of fissure and symptoms on a visual analogue scale (VAS). Following an 8-week course of topical treatment, patients repeated the SF-36 and symptoms were again recorded on a VAS. Healing of fissure was noted. RESULTS: Fifty-four patients entered the study, of which 39 returned for follow-up; 16 male, 23 female; mean age 38.6 years (range 17-80 years). Median duration of fissure was 6 months (3 months - 10 years). Higher VAS ratings for fissure pain were associated with worse scores for all aspects of health-related quality of life, including mental health (P < 0.001), bodily pain (P < 0.001), vitality (P < 0.006) and social functioning (P < 0.001). Compared to age and gender matched norms for the SF-36, fissure patients had more bodily pain (P < 0.001, Wilcoxon) and poorer health perceptions (P < 0.02, Wilcoxon). Gender did not affect any of the SF-36 subscales. However, females did report significantly more bleeding (P = 0.05). On follow-up, healing was complete in 27 patients (69%). Symptoms of pain, bleeding and irritation were all significantly reduced in this group. Repeating the SF-36 showed an improvement in bodily pain, role-physical functioning and vitality (P < 0.05). CONCLUSION: Successful nonsurgical treatment of chronic anal fissure leads to symptomatic improvement and beneficially affects health-related quality of life.

CT in acute mesenteric ischaemia.

Enhanced computed tomography (CT) is frequently performed for possible bowel ischaemia. It has the distinct advantage of possible detection of the causes of ischaemia. Radiologists therefore need to be familiar with the spectrum of diagnostic CT signs. We present the CT imaging findings in surgically proven cases of small bowel ischaemia. In addition to signs pertaining to the underlying aetiological pathology, bowel dilatation, bowel wall thickening, mural gas, occlusion of mesenteric vessels, ascites and infarct of other abdominal organs were observed.

Novel process for generating useful electrophiles from common anions using Selectfluor fluorination agent.

In the present work, the electrophile equivalents Cl+, Br+, SCN+, and NO2+ are generated from their respective sodium, potassium, and in some cases ammonium salts (M+X-) by reaction with Selectfluor electrophilic fluorination agent in acetonitrile solution at room temperature. These generated electrophilic species subsequently react in situ with a variety of aromatic substrates containing one or more substituent groups including H, F, Cl, CH3, COOH, C(O)CH3, NO2, and OR' and NR'R' ' where R' and R' ' are H or CH3. The resulting substitution products are, in most cases, isolable as pure compounds in high yield. Variations in the process include the use of other anions, electrophilic fluorination agents, and solvents.

Substrate and cofactor binding to fluorescently labeled cytoplasmic malate dehydrogenase.

Cytoplasmic malate dehydrogenase (cMDH) is a key enzyme in several metabolic pathways. Though its activity has been examined extensively, there are lingering mechanistic uncertainties involving substrate and cofactor binding. To more completely understand this enzyme's interactions with cofactor and substrate ligands, a fluorescent reporter group was introduced into the enzyme's structure. This was accomplished by selective modification of Cys 110. The reaction placed an aminonaphthaline sulfonic acid group near the enzyme's active site. Substrate, inhibitor, and NAD binding activities were characterized using changes in this label's fluorescence. Results demonstrated that both substrate and cofactor molecules bound to the enzyme in the absence of their companion ligands. This is in contrast to strictly ordered cofactor then substrate binding as has been suggested by kinetic analyses of closely related enzymes. Binding results also indicated that the cofactor, NAD, bound to cMDH in a negatively cooperative manner, but substrates and the inhibitor, hydroxymalonate, bound non-cooperatively. Multiple substrate binding modes were identified and interactions between substrate and cofactor binding were found.

Gastric rupture after Heimlich maneuver and cardiopulmonary resuscitation.

Choking is a common emergency problem. The Heimlich maneuver is unquestionably effective in relieving airway obstruction. Serious and life-threatening complications may arise, however, if the maneuver is applied incorrectly. Two cases of gastric rupture after Heimlich maneuver are reported. Lay public, paramedics and the medical professionals should be educated with the correct technique of Heimlich maneuver and its potential complications. All patients receiving Heimlich maneuver should be examined by an experienced physician.

Thoracoscopic esophageal mobilization for pharyngolaryngoesophagectomy.

BACKGROUND: Pharyngolaryngoesophagectomy (PLE) for hypopharyngeal cancers and tumors of the cervical esophagus is a procedure of significant morbidity and mortality. Conventional esophageal mobilization is performed with the transhiatal dissection technique. Thoracoscopic esophageal mobilization is tested as an alternative to determine whether surgical outcome can be improved. METHODS: From 1994 to 1998, thoracoscopic mobilization was carried out in 30 consecutive patients who underwent PLE (PLE-TS). This was compared to a historical cohort of 30 patients who had PLE with transhiatal mobilization (PLE-TH). RESULTS: In PLE-TS, thoracoscopic esophageal mobilization was successful in 28 patients (93%). Median blood loss was 700 mL (range, 164 to 3,000 mL) compared to 1,000 mL (range, 400 to 2,200 mL) in group PLE-TH, p = 0.21. Thoracoscopy time was 90 minutes (range, 60 to 180 minutes). Total operating time were 392 minutes (range, 180 to 570 minutes) and 300 minutes (range, 150 to 550 minutes) in PLE-TS and PLE-TH, respectively (p = 0.03). Major pulmonary complications occurred in 7 (23%) and 8 (27%) patients in PLE-TS and PLE-TH, respectively (p = 0.77). Cardiac complications occurred in 7 (23%) and 5 (17%) patients in PLE-TS and PLE-TH, respectively (p = 0.52). Thirty-day mortality rates were 3.3% and 10% (p = 0.6) and hospital mortality rates were 13% and 17%, (p = 1.0). CONCLUSIONS: Thoracoscopy was safe and feasible. Morbidity and mortality after PLE was not significantly reduced. The theoretical advantage offered by thoracoscopy may be offset by the lengthened time of one-lung anesthesia.

Esophageal small cell carcinomas: clinicopathologic parameters, p53 overexpression, proliferation marker, and their impact on pathogenesis.

OBJECTIVE: To evaluate the clinicopathologic features and the roles of p53 and MIB-1 in esophageal small cell carcinoma. METHOD: Twenty patients (14 men and 6 women) with esophageal small cell carcinoma treated in our hospital from 1982 through 1996 were studied. The clinicopathologic features, treatment received, and survival data of these patients were documented. Representative tissue was collected from each tumor, and immunohistochemical preparations for p53 protein and MIB-1 were made. RESULTS: Small cell carcinoma accounted for 1.3% of all esophageal malignant tumors. The median age of patients at presentation was 60 years. On gross examination, the tumors were large ulcerative lesions (median length, 7.5 cm). In 17 patients in whom p53 immunohistochemical study was performed, p53 protein was detected in 65% (9 of 17). All stage IV tumors were negative for p53 expression. The median tumor cell MIB-1 score was high at 855 (range, 810-964) positive cells per 1000. Overall median survival was 3.4 months. In patients who underwent chemotherapy, there was significant response. CONCLUSIONS: Esophageal small cell carcinoma is an aggressive tumor. Overexpression of p53 is associated with early stages of carcinogenesis. The high proliferative index, as defined by the MIB-1 immunohistochemical method, may be related to aggressive behavior and high sensitivity to chemotherapy and radiotherapy.

The clinicopathological significance of p21 and p53 expression in esophageal squamous cell carcinoma: an analysis of 153 patients.

OBJECTIVE: The p21 gene is thought to play a central role in tumor suppression. The aim of this study was to examine the clinicopathological role of p21 and p53 in esophageal squamous cell carcinomas. METHODS: The expression of p21 and p53 proteins in 153 Chinese patients (131 men, 22 women) with resected esophageal squamous cell carcinomas was investigated by the immunohistochemical method. Correlation between p21 and p53 expression and clinicopathological features was examined. RESULTS: The expression of p21 and p53 was detected in 70% and 64% of the tumors, respectively. The staining of p21 and p53 was also found in squamous carcinoma in situ, dysplasia, and nontumor epithelium. p21 expression was often weak in the suprabasal cells and found in better differentiated tumors. There was no significant correlation between the expression of p21 and the abnormal accumulation of p53. The prognosis of the patients depended on the size, stage, and p21 expression of the lesion. In stage III lesions with tumor diameter < or = 7.5 cm (n = 93), patients with loss of p21 expression had better survival. The survival rates of patients were worse if they had expression of both p21 and p53. CONCLUSIONS: Thus, p21 and p53 had prognostic value for esophageal squamous cell carcinomas. Loss of p21 expression was shown without p53 alternations, indicating that other mechanisms are also involved in turning off the gene. The pattern of p21 and p53 expression predicts an aggressive clinical course of esophageal squamous cell carcinomas.

Helicobacter pylori status and endoscopy follow-up of patients having a history of perforated duodenal ulcer.

BACKGROUND: The aim of this study was to determine whether the recurrence of symptoms or ulcer disease in patients with a history of perforated duodenal ulcer is related to Helicobacter pylori infection. METHODS: One hundred sixty-three consecutive patients with history of perforated duodenal ulcer unrelated to nonsteroidal anti-inflammatory drugs underwent upper endoscopy. Any recurrent symptoms or complications were documented. Regardless of the endoscopic findings, three antral biopsy specimens were taken for histologic examination and a rapid urease test. RESULTS: There was a preponderance of men (male/female = 5.3:1). The mean age was 55.9 years. Sixty-seven (41.1%) patients gave a history of recurrent epigastric pain, seven of whom also had a history of bleeding ulcer. Upper endoscopy was performed at a mean of 74.5 +/- 7.1 months after operation. Positive endoscopic findings were noted in 68 (41.7%) patients; H. pylori was found in the biopsy specimens from 77 (47.2%) patients. Recurrent duodenal ulcer was found in 29 (17.8%) patients and was significantly related to male gender, recurrent epigastric pain, bleeding ulcer, longer interval from previous operation, and positive H. pylori status. Positive H. pylori status and male gender were independent factors associated with recurrent duodenal ulcer. CONCLUSIONS: Recurrent ulcer disease in patients with a history of perforated duodenal ulcer is related to H. pylori infection.

Laparoscopic insufflation with room air causes exaggerated interleukin-6 response.

BACKGROUND: The gut is a central organ in the postoperative stress reaction. We previously reported that measuring gut-mucosal cytokines may more accurately reflect the response to operative stress. Additionally, we have shown that the gut demonstrates a blunted cytokine response after laparoscopy as compared with laparotomy. METHODS: To further investigate whether this differential response is caused by exposure of the peritoneal cavity to general atmospheric air during laparotomy, 80 A/J mice were randomized equally into four groups: CD (carbon dioxide [CO2] pneumoperitoneum), RA (room air pneumoperitoneum), AP (anesthesia and port insertion only), and PC (pure control, no intervention). Pneumoperitoneum was established and maintained at 3 mmHg for 60 min. All the mice were killed 4 h after the intervention. Jejunal mucosa and serum samples were collected and analyzed for interleukin-6 (IL-6) levels. Results were analyzed by analysis of variance (ANOVA). RESULTS: Gut-mucosal IL-6 in the RA group was significantly higher than in all other groups: RA, 1,354.5 +/- 117.9* vs. CD, 964.3 +/- 114.0 vs. AP, 960.2 +/- 86.2 vs. PC, 908.0 +/- 83.6; *p < 0.05. The CD group did not show a significant increase in gut-mucosal IL-6 as compared with the AP and PC groups. Similarly, RA resulted in significant increases in serum IL-6 as compared with AP and PC, whereas CD showed no significant difference: RA, 161.3 +/- 66.2* vs. 95.1 +/- 1 vs. AP, 10.6 +/- 5.3 vs. PC, undetectable; *p < 0.05. There was no difference in serum IL-6 level between CD or any of the other groups. CONCLUSIONS: Exposure of the peritoneal cavity to atmospheric air, independently of the trauma of abdominal access, causes an exaggerated serum and gut mucosal IL-6 response 4 h after intervention. The beneficial effect of CO2 laparoscopy may be caused by the exclusion of general atmospheric air from the peritoneal cavity.

Esophageal carcinoma in a patient with bleeding esophageal varices.

More than 20 cases of esophageal carcinoma have been reported to develop after endoscopic injection sclerotherapy (EIS), and this technique is implicated in the pathogenesis of esophageal cancer. We report a case of esophageal carcinoma presenting as a superficial ulcer in a patient with esophageal varices with no prior EIS. Whether the development of esophageal carcinoma in patients with previous EIS is coincidental or consequential is controversial. Such carcinoma might have already existed before EIS in some reported cases. A causal relationship between EIS and esophageal carcinoma cannot be established without further clarification by a well-designed study.

Characterization and use of a recombinant retroviral system for the analysis of drug resistant HIV.

A recombinant retroviral system was used for the analysis of early HIV breakthrough infection in the presence of antiviral drugs. The use of replication-defective HIV allowed a quantitative analysis of a single cycle of infection. This report characterizes this recombinant HIV system and demonstrates it's validity in comparison to standard assays. It is demonstrated that the protease inhibitor XM323 inhibits both early and late events in the HIV life-cycle, while dextran sulphate inhibits only early events. In addition, it is shown that this system can be used for detecting and quantitating drug resistant HIV. Thus, the use of this system may provide both novel information about the stage of the viral life-cycle inhibited and a preliminary assessment of the mechanism(s) responsible for breakthrough infection in the presence of antiretroviral drugs.