Cyanine fluorophores for cellular protection against ROS in stimulated macrophages and two-photon ROS detection.

We report the first example of a novel two-photon active, biocompatible, and macrophage cell-membrane permeable carbazole-based cyanine fluorophore for the detection of three biologically important ROS, namely, ˙OH, O2(-) and OCl(-) in solution. This versatile probe shows cellular protection not only in stimulated macrophages from phorbol-12-myristate-13-acetate-induced morphological changes but also lipopolysaccharide-induced cytotoxicity by quenching with the O2(-) and OCl(-) production, respectively. Such protection could be visualized by a distinct change in the fluorescence intensity of the probe.

Microvascular abnormalities in the bulbar conjunctiva of contact lens users.

Soft contact lenses are commonly used to improve vision acuity or in cosmetic enhancement. We hypothesize that contact lens use can cause inadvertent damage to either the conjunctival microcirculation via direct vasoocclusion when the lens physically interacts with or damages the underlying vessels, or to the bulbar conjunctiva itself when the lens rests unevenly on the surface of the bulbar conjunctiva. Computer-assisted intravital microscopy was utilized to document (via video recording) and objectively quantify (via image analysis) real-time microvascular abnormalities resulting from changes and vessel remodeling in the conjunctival microcirculation in long-term (>2 yrs) contact lens users (n = 102), with non-users serving as control subjects (n = 29). A severity index (SI)--computed as the arithmetic sum of the abnormalities found in the conjunctival microcirculation in each contact lens user--was established for objective comparison with control subjects and critical interpretation. Contact lens user SI was significantly higher than control SI (user = 6.21 ± 1.26; control = 2.31 ± 1.49; p < 0.05), indicative of severe vasculopathy arising from contact lens use. The users also had significantly wider conjunctival vessel diameter (user = 71.25 ± 12.09 µm; control = 52.20 ± 5.10 µm; p < 0.05). Additional abnormalities, including damaged vessels, hemosiderin deposits (from damaged vessels or injury to the surface of the bulbar conjunctiva), vessel sludging, intermittent blood flow, and vessel tortuosity were commonly found in or adjacent to locations where the contact lens physically rested on the underlying conjunctival vessels. These results strongly suggest that microvascular abnormalities and remodeling changes occurred as a result of the inadvertent physical interaction of the lenses with either the underlying conjunctival vessels or the surface of the bulbar conjunctiva in contact lens users.

Cost-consequence analysis comparing 2-octyl cyanoacrylate tissue adhesive and suture for closure of simple lacerations: a randomized controlled trial.

STUDY OBJECTIVE: We investigate the cost difference between conventional suture and tissue adhesive methods in simple wound closure. METHODS: A cost-consequence analysis was conducted alongside a nonblinded randomized controlled trial comparing 2-octyl cyanoacrylate tissue adhesive with conventional suture in simple lacerations closure in emergency departments (EDs) of a university teaching hospital and a major regional hospital in Hong Kong. One hundred eighty-six adult patients with simple lacerations of length within 8 cm were randomized to receive tissue adhesive (93 patients) or conventional suture (93 patients) for wound closure. The primary outcome measures were the costs to the Hospital Authority and the charges on participants incurred in each treatment method. The secondary outcome measures included the cosmetic visual analog scale, visual analog scale, Wound Evaluation Score, total time spent in each closure method, and the overall patients' satisfaction on the whole process of wound management. RESULTS: The 2 groups had similar baseline characteristics. The tissue adhesive method incurred a higher cost to the Hospital Authority (216.12 [US $27.70] versus 171.33 [US $21.96]; absolute difference 44.79 [US $5.74] [95% confidence interval (CI) 32.76 to 55.95 [US $4.20 to 7.14]]) but a lower charge to patients (109.68 [US $14.06] versus 156.96 [US $20.12]; absolute difference 47.28 [US $6.06] [95% CI, 35.58 to 58.98 [US $4.56 to 7.56]) than the conventional suture method. The mean cosmetic visual analog scale score, visual analog scale score, and Wound Evaluation Score of the 2 groups were similar at various intervals within 3 months after wound closure. Compared with the suture group, the tissue adhesive group had a shorter median procedure time, fewer patients had wound erythema or swelling after wound closure, fewer patients required analgesics on discharge at ED, and there was a higher overall patient satisfaction score. CONCLUSION: Simple wounds closed by tissue adhesives incur a higher cost to the Hospital Authority than the conventional suture but may be favored by patients because of lower personal charge.

Patients' perceptions of nasopharyngeal aspiration in the emergency department of a teaching hospital in Hong Kong.

Nasopharyngeal aspiration (NPA) is the preferred method for collecting specimens for viral culture in patients with respiratory tract infection. As virus identification may influence admission and treatment decisions, it is important to perform NPA in the emergency department. The test may be uncomfortable and poorly tolerated. This prospective study investigated patients' perceptions of NPA. Patients in the emergency department with upper respiratory tract infection undergoing NPA between 9 March 2005 and 12 August 2005 were included. 86 patients (mean (SD) age 47 (23) years; 49 women) were recruited. 22 (26%) patients complained that NPA was very uncomfortable, 59 (69%) reported that it was mildly uncomfortable and 5 (6%) patients reported no discomfort. On a 10-point scale, the median discomfort score was 4. 29 (34%) patients stated that NPA was more uncomfortable than blood taking, 19 (22%) patients felt that both were similar and 38 (44%) patients felt that NPA was less uncomfortable (p value not significant). NPA performed in the emergency department is well tolerated and should be considered in emergency departments when results may influence patient management.

Modulation by homocysteine of the iberiotoxin-sensitive, Ca2+ -activated K+ channels of porcine coronary artery smooth muscle cells.

We evaluated the acute effect of homocysteine on the iberiotoxin-sensitive, Ca(2+)-activated K(+) (BK(Ca)) channels of the porcine coronary artery smooth muscle cells. NS 1619 (1 to 30 microM) caused a concentration-dependent enhancement of the BK(Ca) amplitude (recorded using the whole-cell, membrane-rupture configuration) only with an elevated [Ca(2+)](i) of approximately 444 nM, but not with [Ca(2+)](i) of approximately 100 nM. Homocysteine (30 microM) caused a small inhibition ( approximately 16%) of the BK(Ca) amplitude ([Ca(2+)](i)= approximately 444 nM), and a greater inhibition ( approximately 77%) was observed with 100 microM NADH present in the pipette solution. The inhibition persisted after washing. With NADPH (100 microM), a smaller magnitude of inhibition ( approximately 34%) of the BK(Ca) amplitude was recorded. The NS 1619-mediated enhancement of the BK(Ca) amplitude (with elevated [Ca(2+)](i) plus NADH in the pipette) was attenuated by homocysteine. The homocysteine-mediated inhibition of the BK(Ca) amplitude was suppressed by Tiron (10 mM) or diphenylene iodonium (30 nM), applied alone, but not by superoxide dismutase (500 U/ml) and catalase (500 U/ml). Generation of superoxide (O(2)(-)) of the smooth muscle cells (with NADH presence), measured using the lucigenin-enhanced chemiluminescence, was markedly increased by angiotensin II (100 nM) and homocysteine (30 microM). The chemiluminescence signal was sensitive to apocynin (300 microM) or Tiron, applied alone, but not to superoxide dismutase and catalase. In conclusion, our results demonstrate that acute homocysteine application inhibits the iberiotoxin-sensitive BK(Ca) channels (with elevated [Ca(2+)](i) and NADH present) which is probably caused by the NADH oxidase activation and the concomitant generation of intracellular superoxide.

Photocatalytic degradation of water-soluble organic pollutants on TiO2 modified with gold nanoparticles.

Well characterised novel catalysts consisting of TiO2 modified with very small amounts of gold nanoparticles have been applied to the photocatalytic degradation of two important pollutants, methyl tert-butyl ether (MTBE) and 4-chlorophenol, in dilute aqueous solution using a fixed bed flow-through photocatalytic reactor. Although the thermal processing that was necessary for coating the reactor walls with the photocatalysts did lead to some loss of performance, the net gains in activity relative to unmodified TiO2 were nevertheless substantial and in excess of anything previously reported. Improvements in reaction rate by 50% and 100% for the removal of 4-chlorophenol and MTBE, respectively, were achieved. It was also found that effective removal of both pollutants could be achieved at water flow rates that are relevant to field applications involving the photocatalytic clean-up of contaminated groundwater. Due to their very small Au content, the cost of these materials is compatible with large scale use.

Successful treatment of spinal cord compression secondary to extramedullary hematopoietic mass by hypertransfusion in a patient with thalassemia major.

A 15-year-old girl with thalassemia major who suffered from paraparesis with a history of progressive lower limb weakness for 2 years immigrated from mainland China to Hong Kong. She had not received regular blood transfusion since the age of 6 years after splenectomy. MRI of the spine showed thoracic spinal cord compression secondary to extramedullary hematopoietic mass. She made significant recovery with hypertransfusion therapy alone. MRI of the spine repeated 3 months later showed nearly complete resolution of the extramedullary hematopoietic mass.

MR imaging of the brain in patients cured of acute lymphoblastic leukemia--the value of gradient echo imaging.

BACKGROUND AND PURPOSE: Hemosiderin and white matter lesions are 2 of the most common neurologic complications found on MR imaging that may be related to cranial irradiation and intrathecal methotrexate (MTX) therapy in childhood acute lymphoblastic leukemia (ALL). We evaluated the brains of patients previously treated for ALL with cranial irradiation and intrathecal MTX with MR imaging and tested the hypothesis that these patients have more MR evidence of central nervous system (CNS) injury than control patients who are in complete remission following systemic chemotherapy without cranial irradiation. METHODS AND MATERIALS: ALL patients recruited from a pediatric cancer center data base were examined at 1.5T by using T1-weighted, T2-weighted, gradient echo (GE), and fluid-attenuated inversion recovery sequences. Patients treated in childhood for solid extracranial neoplasms were used as controls. RESULTS: Lesions consistent with old hemorrhage were detected in 23 (55%) of the ALL patients and in none of the control patients (P <.001). Of the 62 hemorrhages detected on the GE images, only 9 (15%) were shown on T2-weighted images. White matter abnormalities were found in 2 ALL patients (5%) and one control patient (5%). Old infarcts were seen in 2 ALL patients (10%). CONCLUSION: Cerebral hemorrhages related to radiation-induced vascular malformations, most of which are asymptomatic, are much more common in survivors of childhood ALL than previously thought. GE sequencing is more sensitive in detecting hemorrhagic lesions than T2-weighted sequencing and is to be included in imaging protocols for follow-up study of patients after cerebral radiation therapy.

Estimating geriatric patient's body weight using the knee height caliper and mid-arm circumference in Hong Kong Chinese.

The use of the knee height caliper is a convenient way to estimate a patient's body weight. However, the equation devised to estimate an individual's body weight was specifically designed for Caucasians and Blacks. Therefore, this study is to assess the suitability of the knee height caliper among Chinese geriatric patients residing in Hong Kong. Over a six-month period, all geriatric patients from an acute care hospital and private nursing home in the Kwun Tong were recruited into the study. Only patients/residents that were considered unstable with ascites; low blood pressure; on cardiac monitors or had respiratory difficulties were excluded. Measurements from the knee height caliper and mid-arm muscle circumference of the patients were necessary for estimating their body weights. The actual body weights measured with calibrated bed, chair or portable scales was compared with the calculated body weights from the equation. A comparison of the mean and linear regression was performed for analysis of the results. A total of 300 geriatric patients (200 females and 100 males) were recruited. The mean MAC and knee height results were as follows: 25.1 cm (SD 3.9) for females and 26.2 cm (SD 3.2) for males; and 45.75 cm (SD 2.09) for females and 48.98 cm (SD 2.09) for males respectively. The mean difference among the male group was 0.4222 (95% CI: -0.54, 1.39) with a mean estimated body weight of 58.1 kg (SD 10.1) and a mean actual body weight of 57.7 kg (SD 9.9). The mean difference among the female group was 2.9649 (95% CI: 2.30, 3.63) with a mean estimated body weight of 51.6 kg (SD 10.9) and a mean actual body weight of 48.6 kg (SD 10.1). A new equation devised from the data is as follows: Chinese males (over 60 years of age) (R-square -0.81) Weight = [knee height (cm) x 0.928 + mid-arm circumference (cm) x 2.508 - age (years) x 0.144] - 42.543 +/-9.9kg of actual weight for 95% of Chinese males; Chinese females (over 60 years of age) (R-square - 0.82) Weight (kg) = [knee height (cm) x 0.826 + mid-arm circumference (cm) x 2.116 - age (years) x 0.133] - 31.486 +/-10.1kg of actual weight for 95% of Chinese females. The results showed that the mean estimated body weight calculated from the knee height equation (for Caucasians) was significantly larger than the mean actual body weight for the Chinese subjects. This study suggests that the knee height caliper is a useful tool for estimating the body weights. However, a multi-center study is necessary to validate the new equation for the elderly Chinese population.

Endovascular GDC-mediated flow-reversal for complex posterior circulation saccular aneurysms. A report of two cases and critical appraisal.

Two patients with giant complex saccular aneurysms of the proximal basilar artery were managed with flow-reversal using the endovascular route. Complete obliteration of the aneurysm was successful in one patient resulting in long term survival (8 year follow-up completed). Incomplete obliteration of the aneurysm persisted in the other patient, resulting in recurrence and a fatal haemorrhage one year after treatment. Endovascular flow-reversal is a good treatment option for these lesions with a high surgical risk. However, persistent incomplete thrombosis of these aneurysms following flow-reversal should lead to the consideration of alternate treatment strategies.

Discrimination of an infected brain tumor from a cerebral abscess by combined MR perfusion and diffusion imaging.

The aim of this study was to investigate the signal characteristics of the abscess wall and tumor wall on diffusion-weighted and perfusion-weighted images and thus to evaluate the feasibility of using combined MR diffusion and perfusion imaging to differentiate pyogenic cerebral abscess from infected brain tumor. The tumor wall of various types of cystic or necrotic brain tumor was significantly hyperintense relative to that of cerebral abscess wall on both diffusion-weighted images and regional cerebral blood volume maps. Sixteen patients who had cerebral masses with large cystic or necrotic cavities were imaged to generate diffusion-weighted images and regional cerebral blood volume maps using single-shot echoplanar imaging (EPI) pulse sequences. Apart from qualitative analysis, apparent diffusion coefficients (ADC) as well as regional cerebral blood volume (rCBV) ratios were calculated from the abscess wall and peripheral tumor wall and comparison was made by using Student's t-test. The tumor wall of various types of cystic or necrotic brain tumor had significantly lower ADCs relative to those of the abscess wall (P<0.005) and thus appeared relatively hyperintense on diffusion-weighted images. The mean rCBV ratio relative to normal white matter (2.90+/-0.62) of the peripheral tumor wall of various types of cystic or necrotic brain tumor were significantly larger than the mean rCBV ratio (0.45+/-0.11) of the pyogenic cerebral abscess wall (P<0.001) by Student's t-test. It is concluded that the combined MR diffusion and perfusion imaging might be capable of differentiating an infected brain tumor from a pyogenic cerebral abscess.

Childhood posterior fossa pial-dural arteriovenous fistula treated by endovascular occlusion.

Posterior fossa dural arteriovenous fistulae in children are rare lesions that are difficult to treat effectively. We report a case of a 2-year-old girl with such a fistula, who presented clinically with progressive neurological deficit. The lesion was treated by endovascular occlusion, resulting in radiological and clinical cure.

Sequence type analysis and recombinational tests (START).

UNLABELLED: The 32-bit Windows application START is implemented using Visual Basic and C(++) and performs analyses to aid in the investigation of bacterial population structure using multilocus sequence data. These analyses include data summary, lineage assignment, and tests for recombination and selection. AVAILABILITY: START is available at http://outbreak.ceid.ox.ac.uk/software.htm. CONTACT: keith.jolley@ceid.ox.ac.uk

Database-driven multi locus sequence typing (MLST) of bacterial pathogens.

MOTIVATION: Multi Locus Sequence Typing (MLST) is a newly developed typing method for bacteria based on the sequence determination of internal fragments of seven house-keeping genes. It has proved useful in characterizing and monitoring disease-causing and antibiotic resistant lineages of bacteria. The strength of this approach is that unlike data obtained using most other typing methods, sequence data are unambiguous, can be held on a central database and be queried through a web server. RESULTS: A database-driven software system (mlstdb) has been developed, which is used by public health laboratories and researchers globally to query their nucleotide sequence data against centrally held databases over the internet. The mlstdb system consists of a set of perl scripts for defining the database tables and generating the database management interface and dynamic web pages for querying the databases. AVAILABILITY: http://www.mlst.net.

The effects of hemoglobin glutamer-200 (bovine) on the microcirculation in a canine hypovolemia model: a noninvasive computer-assisted intravital microscopy study.

UNLABELLED: We sought to correlate in vivo microvascular, systemic function, hemodynamic, and oxygenation changes in autologous shed blood (n = 4) and hemoglobin glutamer-200 (Hb-200) (n = 4) resuscitations in hypovolemic dogs. Hemorrhage (approximately 40% blood loss) reduced mean arterial pressure to approximately 50 mm Hg and caused significant (P < 0.01) decreases in hematocrit, total hemoglobin, mean pulmonary arterial pressure, cardiac output, and oxygen delivery and significant (P < 0.01) increases in heart rate, systemic vascular resistance, and lactic acidosis. Significant (P < 0.01) changes in conjunctival microvascular variables also occurred, including a 19% decrease in venular diameter and 79% increase in average blood flow velocity. Shed blood resuscitation returned microvascular, systemic function, hemodynamic, and oxygenation variables to prehemorrhagic baseline values. In contrast, Hb-200 failed to restore hematocrit, total hemoglobin, cardiac output, oxygen delivery index, and systemic venous resistance to baseline, but it restored other systemic functions and all hemodynamic and microvascular changes. In addition, Hb-200 resuscitation in hypovolemic dogs (approximately 40% blood loss) did not cause extreme hemodilution or fatal outcome. This study confirms that real-time (in vivo) microvascular studies, which were conducted only in small rodent models in the past, can be performed simultaneously with systemic function, hemodynamic, and oxygenation studies in a large animal model for relevant data correlation. IMPLICATIONS: This is the first time that changes in the blood circulation have been studied, quantified, and correlated with systemic function, hemodynamic, and oxygenation changes in shock and during shock treatment in a large animal model. This study was performed by a new technology developed in-house to noninvasively and quantitatively study blood vessels in real time.

MR diffusion-weighted imaging of kidney: differentiation between hydronephrosis and pyonephrosis.

The objective of the study was to evaluate the capability and reliability of the magnetic resonance (MR) diffusion-weighted imaging (DWI) in differentiation between hydronephrosis and pyonephrosis. Single-shot echoplanar MR diffusion-weighted imaging was performed in 12 patients who had dilatation of the renal pelvis and calyces detected by ultrasonography (US). Microbiological tests confirmed that there were four cases of pyonephrosis and eight cases of hydronephrosis. Signal intensities of the collecting (pelvicalyceal) systems on the diffusion-weighted images and apparent diffusion coefficient (ADC) maps were noted. ADC values of the pelvicalyceal system in all patients were computed and compared using Student's t test. On diffusion-weighted images, the pelvicalyceal system of the hydronephrotic kidney was hypointense while the pelvicalyceal system of the pyonephrotic kidney was markedly hyperintense. The mean ADCs of the hydronephrotic and pyonephrotic renal pelvis were 2.98 +/- 0.65 x 10(-3) and 0.64 +/- 0.35 x 10(-3) mm(2)/s, respectively. The extremely low ADC of the renal pelvis of the pyonephrotic kidney accounted for its signal hyperintensity on diffusion-weighted images as well as signal hypointensity on ADC maps. In conclusion, the MR diffusion-weighted imaging may be a reliable tool to differentiate pyonephrosis from hydronephrosis.

Methods for estimation of associations between multiple species parasite infections.

Human populations are often infected with more than one species of parasite, especially in developing countries where overall rates of parasitism are high. Infections with multiple parasite species may not necessarily be independent within an individual as physiological, immunological or ecological factors may result in positive or negative associations between infections with different parasite species. A general framework for estimation of these associations is presented. Data from over 215000 individuals are analysed and the associations between geohelminth (Ascaris lumbricoides, Trichuris trichiura and hookworm) and malaria species are investigated. A method is presented for analysing data from multiple communities and testing whether the associations in different communities are equal. Overall estimates of the associations between species are obtained for each country and continent where data were available. Associations between geohelminth species were, in general, found to be positive whilst both positive and negative associations were found between the different Plasmodium species. There was evidence for significant geographical heterogeneity between the associations. A method for using these parameter estimates to predict the distribution of multiple infections when only marginal prevalence data are available is described and demonstrated.

Recombination within natural populations of pathogenic bacteria: short-term empirical estimates and long-term phylogenetic consequences.

The identification of clones within bacterial populations is often taken as evidence for a low rate of recombination, but the validity of this inference is rarely examined. We have used statistical tests of congruence between gene trees to examine the extent and significance of recombination in six bacterial pathogens. For Neisseria meningitidis, Streptococcus pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus, the congruence between the maximum likelihood trees reconstructed using seven house-keeping genes was in most cases no better than that between each tree and trees of random topology. The lack of congruence between gene trees in these four species, which include both naturally transformable and nontransformable species, is in three cases supported by high ratios of recombination to point mutation during clonal diversification (estimates of this parameter were not possible for Strep. pyogenes). In contrast, gene trees constructed for Hemophilus influenzae and pathogenic isolates of Escherichia coli showed a higher degree of congruence, suggesting lower rates of recombination. The impact of recombination therefore varies between bacterial species but in many species is sufficient to obliterate the phylogenetic signal in gene trees.