Impact of a novel pre-hospital stroke notification programme on acute stroke care key performance indicators in Hong Kong: a multicentre prospective cohort study with historical controls.

INTRODUCTION: Early identification and initiation of reperfusion therapy is essential for suspected acute ischaemic stroke. A pre-hospital stroke notification (PSN) protocol using FASE (facial drooping, arm weakness, speech difficulties, and eye palsy) was implemented to improve key performance indicators (KPIs) in acute stroke care delivery. We assessed KPIs and clinical outcomes before and after PSN implementation in Hong Kong. METHODS: This prospective cohort study with historical controls was conducted in the Accident and Emergency Departments of four public hospitals in Hong Kong. Patients were screened using the PSN protocol between August 2021 and February 2022. Suspected stroke patients between August 2020 and February 2021 were included as historical controls. Door-to-needle (DTN) and door-to-computed tomography (DTC) times before and after PSN implementation were compared. Clinical outcomes including National Institutes of Health Stroke Scale score at 24 hours and modified Rankin Scale score at 3 months after intravenous recombinant tissue-type plasminogen activator (IV-rtPA) were also assessed. RESULTS: Among the 715 patients (266 PSN and 449 non-PSN) included, 50.8% of PSN patients and 37.7% of non-PSN patients had a DTC time within 25 minutes (P<0.001). For the 58 PSN and 134 non-PSN patients given IV-rtPA, median DTN times were 67 and 75.5 minutes, respectively (P=0.007). The percentage of patients with a DTN time within 60 minutes was higher in the PSN group than in the non-PSN group (37.9% vs 21.6%; P=0.019). No statistically significant differences in clinical outcomes were observed. CONCLUSION: Although the PSN protocol shortened DTC and DTN times, clinical outcomes did not significantly differ.

Lymphoma in Australian Border Collies: survey results and pedigree analyses.

OBJECTIVES: The aims of this study were to (1) describe the results of a survey on the clinical features of lymphoma in Australian Border Collies and (2) investigate familial clustering of lymphoma-affected dogs by means of pedigree analyses. METHODS: Clinical and pedigree information was collected from surveys completed by owners or breeders of Australian Border Collies. Relationships between dogs were derived from pedigree data and kinship was analysed by network and cluster-based algorithms. RESULTS: A total of 246 respondents completed the survey and 57 lymphoma-affected Australian Border Collies were identified. The mean age of diagnosis was 9.16 (SD ± 3.43) years and the median was 9.7 years (range 2-15 years). The odds of female dogs affected with lymphoma were twice those of males in the reported data (OR = 2.06; 95% CI = 1.13-3.73; P = 0.02). Multicentric, high-grade B-cell lymphoma was the most common form in these dogs. Pedigree analyses identified 21 affected dogs that descended from two sires and 28 cases with a common female ancestor. Average inbreeding between both affected and unaffected dogs was similar (0.16, SD ± 0.06 and 0.15, SD ± 0.06, respectively). CONCLUSION: The survey confirmed the presence of a relatively large number of cases of lymphoma in Australian Border Collies, consistent with our previous report of increased risk in this breed. Some dogs were diagnosed at a very young age, but the age ranged over the normal lifespan. Pedigree analyses identified multiple cases within family groups, suggesting a heritable component of the disease in this breed.

Multistage leaching of metals from spent lithium ion battery waste using electrochemically generated acidic lixiviant.

Lithium ion battery (LIB) waste contains significant valuable resources that could be recovered and reused to manufacture new products. This study aimed to develop an alternative process for extracting metals from LIB waste using acidic solutions generated by electrolysis for leaching. Results showed that solutions generated by electrolysis of 0.5 M NaCl at 8 V with graphite or mixed metal oxide (MMO) electrodes were weakly acidic and leach yields obtained under single stage (batch) leaching were poor (<10%). This was due to the highly acid-consuming nature of the battery waste. Multistage leaching with the graphite electrolyte solution improved leach yields overall, but the electrodes corroded over time. Though yields obtained with both electrolyte leach solutions were low when compared to the 4 M HCl control, there still remains potential to optimise the conditions for the generation of the acidic anolyte solution and the solubilisation of valuable metals from the LIB waste. A preliminary value proposition indicated that the process has the potential to be economically feasible if leach yields can be improved, especially based on the value of recoverable cobalt and lithium.

Desoxycorticosterone pivalate-salt treatment leads to non-dipping hypertension in Per1 knockout mice.

AIM: Increasing evidence demonstrates that circadian clock proteins are important regulators of physiological functions including blood pressure. An established risk factor for developing cardiovascular disease is the absence of a blood pressure dip during the inactive period. The goal of the present study was to determine the effects of a high salt diet plus mineralocorticoid on PER1-mediated blood pressure regulation in a salt-resistant, normotensive mouse model, C57BL/6J. METHODS: Blood pressure was measured using radiotelemetry. After control diet, wild-type (WT) and Per1 (KO) knockout mice were given a high salt diet (4% NaCl) and the long-acting mineralocorticoid deoxycorticosterone pivalate. Blood pressure and activity rhythms were analysed to evaluate changes over time. RESULTS: Blood pressure in WT mice was not affected by a high salt diet plus mineralocorticoid. In contrast, Per1 KO mice exhibited significantly increased mean arterial pressure (MAP) in response to a high salt diet plus mineralocorticoid. The inactive/active phase ratio of MAP in WT mice was unchanged by high salt plus mineralocorticoid treatment. Importantly, this treatment caused Per1 KO mice to lose the expected decrease or 'dip' in blood pressure during the inactive compared to the active phase. CONCLUSION: Loss of PER1 increased sensitivity to the high salt plus mineralocorticoid treatment. It also resulted in a non-dipper phenotype in this model of salt-sensitive hypertension and provides a unique model of non-dipping. Together, these data support an important role for the circadian clock protein PER1 in the modulation of blood pressure in a high salt/mineralocorticoid model of hypertension.

Cutaneous adverse food reactions in cats: retrospective evaluation of 17 cases in a dermatology referral population (2001-2011).

OBJECTIVE: To better characterise cutaneous adverse food reactions (AFR) in cats, including the diagnostic challenges. DESIGN: Retrospective evaluation of cases presenting to a dermatology referral service. METHODS: Cats were identified by a computerised medical record search. AFR was confirmed by clear deterioration on normal food re-challenge after completing an elimination diet, followed by improvement returning to the test diet. Prevalence, and breed, sex or age predispositions were compared with the base referral population. Patient records were reviewed for historical features, clinical presentations, concurrent dermatoses and dietary details. RESULTS: A total of 17 cats were identified with cutaneous AFR, with no breed or sex predisposition determined. Age of onset ranged from 3 months to 9 years, with a mean of 3.5 years. Prevalence was 6% of dermatoses and 10% of cutaneous hypersensitivities in the referral cat population. Cats typically presented with severe, perennial, non-seasonally flaring pruritus affecting the face/head, neck and/or ventral abdomen. Concurrent hypersensitivities were confirmed in 6 cats and/or suspected in another 5 cats. Home-prepared elimination diets were completed by 16 cats; 8 cats had initial poor response to minimum 6-week commercial hydrolysed protein diets. Identified adverse foods included fish in 2 cats, and chicken, beef, commercial dry, and some canned foods, each in 1 cat. CONCLUSIONS: The prevalence of cutaneous AFR in the general cat population is likely to be greater than 6%. A range of clinical presentations occur and practical challenges to diagnosis include reliance on strict adherence to dietary exclusion/provocation trials and misleading responses related to concurrent dermatoses and owner perceptions.

Simultaneous introduction of a novel high fat diet and wheel running induces anorexia.

Voluntary wheel running (WR) is a form of physical activity in rodents that influences ingestive behavior. The present report describes an anorexic behavior triggered by the simultaneous introduction of a novel diet and WR. This study examined the sequential, compared with the simultaneous, introduction of a novel high-fat (HF) diet and voluntary WR in rats of three different ages and revealed a surprising finding; the simultaneous introduction of HF food and voluntary WR induced a behavior in which the animals chose not to eat although food was available at all times. This phenomenon was apparently not due to an aversion to the novel HF diet because introduction of the running wheels plus the HF diet, while continuing the availability of the normal chow diet did not prevent the anorexia. Moreover, the anorexia was prevented with prior exposure to the HF diet. In addition, the anorexia was not related to extent of WR but dependent on the act of WR. The introduction a HF diet and locked running wheels did not induce the anorexia. This voluntary anorexia was accompanied by substantial weight loss, and the anorexia was rapidly reversed by removal of the running wheels. Moreover, the HF/WR-induced anorexia is preserved across the age span despite the intrinsic decrease in WR activity and increased consumption of HF food with advancing age. The described phenomenon provides a new model to investigate anorexia behavior in rodents.

POMC overexpression in the ventral tegmental area ameliorates dietary obesity.

The activation of proopiomelanocortin (POMC) neurons in different regions of the brain, including the arcuate nucleus of the hypothalamus (ARC) and the nucleus of the solitary tract curtails feeding and attenuates body weight. In this study, we compared the effects of delivery of a recombinant adeno-associated viral (rAAV) construct encoding POMC to the ARC with delivery to the ventral tegmental area (VTA). F344×Brown Norway rats were high-fat (HF) fed for 14 days after which self-complementary rAAV constructs expressing either green fluorescent protein or the POMC gene were injected using coordinates targeting either the VTA or the ARC. Corresponding increased POMC levels were found at the predicted injection sites and subsequent α-melanocyte-stimulating hormone levels were observed. Food intake and body weight were measured for 4 months. Although caloric intake was unaltered by POMC overexpression, weight gain was tempered with POMC overexpression in either the VTA or the ARC compared with controls. There were parallel decreases in adipose tissue reserves. In addition, levels of oxygen consumption and brown adipose tissue uncoupling protein 1 were significantly elevated with POMC treatment in the VTA. Interestingly, tyrosine hydroxylase levels were increased in both the ARC and VTA with POMC overexpression in either the ARC or the VTA. In conclusion, these data indicate a role for POMC overexpression within the VTA reward center to combat HF-induced obesity.

Pro-opiomelanocortin gene transfer to the nucleus of the solitary track but not arcuate nucleus ameliorates chronic diet-induced obesity.

Short-term pharmacological melanocortin activation deters diet-induced obesity (DIO) effectively in rodents. However, whether central pro-opiomelanocortin (POMC) gene transfer targeted to the hypothalamus or hindbrain nucleus of the solitary track (NTS) can combat chronic dietary obesity has not been investigated. Four-weeks-old Sprague-Dawley rats were fed a high fat diet for 5 months, and then injected with either the POMC or control vector into the hypothalamus or NTS, and body weight and food intake recorded for 68 days. Insulin sensitivity, glucose metabolism and adrenal indicators of central sympathetic activation were measured, and voluntary wheel running (WR) assessed. Whereas the NTS POMC-treatment decreased cumulative food consumption and caused a sustained weight reduction over 68 days, the hypothalamic POMC-treatment did not alter cumulative food intake and produced weight loss only in the first 25 days. At death, only the NTS-POMC rats had a significant decrease in fat mass. They also displayed enhanced glucose tolerance, lowered fasting insulin and increased QUICK value, and elevated adrenal indicators of central sympathetic activation. Moreover, the NTS-POMC animals exhibited a near 20% increase in distance ran relative to the respective controls, but the ARC-POMC rats did not. In conclusion, POMC gene transfer to the NTS caused modest anorexia, persistent weight loss, improved insulin sensitivity, and increased propensity for WR in DIO rats. These metabolic improvements may involve stimulation of energy expenditure via centrally regulated sympathetic outflow. The similar POMC treatment in the hypothalamus had minimal long-term physiological or metabolic impact. Thus, melanocortin activation in the brainstem NTS region effectively ameliorates chronic dietary obesity whilst that in the hypothalamus fails to do so.

Effects of pig manure compost and nonionic-surfactant Tween 80 on phenanthrene and pyrene removal from soil vegetated with Agropyron elongatum.

This paper evaluates the effects of pig manure compost (PMC) and Tween 80 on the removal of phenanthrene (PHE) and pyrene (PYR) from soil cultivated with Agropyron elongatum. Soils spiked with about 300 mg kg(-1) of PHE and PYR were individually amended with 0%, 2.5%, 5% and 7.5% (dry wt) of PMC or 0, 20 and 100 mg kg(-1) of Tween 80. Unplanted and sterile microcosms were prepared as the controls. PAH concentration, total organic matter (TOM), dissolved organic carbon (DOC), total heterotrophic and PAH degrading microbial populations in soil were quantified before and after 60d period. The results indicated that A. elongatum could significantly enhance PYR removal (from 46% to 61%) but had less impact on PHE removal (from 96% to 97%). Plant uptake of the PAHs was insignificant. Biodegradation was the key mechanism of PAH removals (<3% losses in the sterile control). Increase in PMC or Tween 80 levels increased the removal of PYR but not of PHE. Maximal PYR removal of 79% and 92% were observed in vegetated soil receiving 100 mg kg(-1) Tween 80 and 7.5% PMC, respectively. Enhanced PYR removal in soil receiving PMC could be explained by the elevated levels of DOC, TOM and microbial populations as suggested by Pearson correlation test. While the positive effect of Tween 80 on PYR removal could probably due to its capacities to enhance PYR bioavailability in soil. This paper suggests that the addition of either PMC or nonionic-surfactant Tween 80 could facilitate phytoremediation of PAH contaminated soil.

Lean rats with hypothalamic pro-opiomelanocortin overexpression exhibit greater diet-induced obesity and impaired central melanocortin responsiveness.

AIMS/HYPOTHESIS: Central pro-opiomelanocortin (Pomc) gene therapy ameliorates genetic- or age-related obesity. We hypothesised that this treatment would delay or prevent dietary obesity in young, lean rats. MATERIALS AND METHODS: Recombinant adeno-associated virus encoding Pomc (rAAV-Pomc) was delivered bilaterally into the basomedial hypothalamus of lean rats for 42 days. Food intake, body weight, serum hormones, brown adipose tissue (BAT) uncoupling protein 1 (UCP1) and mRNA levels of hypothalamic neuropeptides and melanocortin receptors were assessed. Beginning on day 43, half of the rats remained on chow while the others received a high-fat diet for 89 days. We examined energy balance and responsiveness to the melanocortin agonist melanotan II (MTII) or the antagonist SHU9119. RESULTS: Pomc gene delivery produced elevated hypothalamic Pomc mRNA (fourfold) and alpha-melanocyte-stimulating hormone levels in the arcuate nucleus (twofold). Food intake and body weight were not altered by rAAV-Pomc in rats fed standard-chow. In rAAV-Pomc rats at day 42, perirenal fat and serum leptin decreased but overall visceral adiposity did not; expression of the hypothalamic agouti-related protein (Agrp) mRNA was elevated, whereas expression of melanocortin 3 and 4 receptor mRNA was reduced; BAT UCP1 protein increased nearly fourfold. The rAAV-Pomc rats fed the high-fat diet consumed more energy and gained more body weight compared with chow- or high-fat-fed controls that did not receive Pomc gene delivery. The anorexic response to MTII was impaired, whereas the orexigenic effect of SHU9119 was enhanced by rAAV-Pomc pretreatment. CONCLUSIONS/INTERPRETATION: Delivery of the Pomc gene alters energy homeostasis in lean rats, predisposing them to diet-induced obesity. Diminished hypothalamic melanocortin receptors, increased Agrp expression, and potential rewiring of brain circuits may underlie the exacerbated obesity.

Effect of synthetic surfactants on the solubilization and distribution of PAHs in water/soil-water systems.

The present study examined the effects of four surfactants, including three non-ionic surfactants (Tween 80, Triton X-100 and Brij 35) and an anionic surfactant SDS on the solubilization and distribution of phenanthrene (Phe) and pyrene (Pyr) in soil-water systems. All four surfactants could enhance the solubilization of Phe and Pyr in aqueous phase linearly when surfactant concentrations exceeded their respective critical micelle concentrations (CMC). Molar solubilization ratio (MSR) which indicated surfactant's solubilization capacity for Phe and Pyr, was highest for Tween 80 for both PAHs, and SDS had the lowest among the four surfactants, while Triton X-100 and Brij 35 had about the same MSR for both PAHs. Moreover, all the surfactants could provide a strong micelle partitioning phase for the more hydrophobic Pyr than Phe as revealed by their high micelle--aqueous phase partition coefficient, K(mc). Batch desorption studies also demonstrated that Tween 80 had the best capacity for the desorption of both Phe and Pyr in the soil-water systems, and followed by Triton X-100 and Brij 35, while SDS seems to have no positive effect on the desorption of PAHs probably due to its relatively high CMC value. Therefore, from the application standpoint, the results obtained in this study suggest that Tween 80 would be the most suitable candidate among the four surfactants in improving solubilization and desorption of PAHs in soil-water system, which are believed to be the prerequisites for successful bioremediation technology for PAH contaminated soil.

Pandrug-resistant Pseudomonas aeruginosa among hospitalised patients: clinical features, risk-factors and outcomes.

Between 1 January 2003 and 31 December 2003, 37 patients had positive cultures of pandrug-resistant Pseudomonas aeruginosa (PDRPA) resistant to all commercially available anti-pseudomonal antimicrobial agents in Taiwan, including anti-pseudomonal penicillins, ceftazidime, fourth-generation cephalosporins, aztreonam, carbapenems, aminoglycosides and ciprofloxacin. Nineteen (51.4%) patients had PDRPA infections, including pneumonia (17 patients), catheter-related bacteraemia (one patient) and anal abscess (one patient). Eighteen patients were classified as having PDRPA colonisation, based on absence of clinical signs or symptoms of infection. In total, 92 isolates were recovered from various specimens, with the majority (85.9%) recovered from respiratory tract secretions (sputa, bronchial washings and pleural effusions), followed by urine (4.3%) and catheter tips (3.3%). Twenty-eight (75.7%) patients yielded cultures of non-PDR P. aeruginosa isolates before isolation of PDRPA, with a mean period between the first isolation of non-PDR P. aeruginosa and the isolation of PDRPA of 128.3 days. Most patients had received beta-lactam antibiotics, fluoroquinolones or carbapenems for prolonged periods. Univariate analysis showed that PDRPA infection, male gender and the presence of fever at the time of PDRPA isolation were associated with increased mortality.

Combined effect of nonionic surfactant Tween 80 and DOM on the behaviors of PAHs in soil--water system.

Batch experiments were performed to examine the desorption behavior of phenanthrene and pyrene in soil-water system in the presence of nonionic surfactant Tween 80 and dissolved organic matter (DOM) derived from pig manure or pig manure compost. Addition of 150 mgl(-1) Tween 80 desorbed 5.8% and 2.1% of phenanthrene and pyrene from soil into aqueous phase, respectively, while the addition of both Tween 80 and DOM derived from pig manure compost and pig manure could further enhance the desorption of phenanthrene to 15.8% and 16.2%, respectively, and 6.4% and 10.9%, respectively, for pyrene. In addition, our finding also suggested that subsequent addition of Tween 80 into the soil-water system could further enhance PAHs desorption. The enhancement effect of the co-existence of Tween 80 and DOM was more than the additive effect of the Tween 80 and DOM individually. It is likely that the formation of DOM-surfactant complex in the soil-water system may be a possible reason to explain such desorption enhancement phenomenon. Therefore, it is anticipated that the coexistence of both Tween 80 and DOM derived from pig manure or pig manure compost in soil environment will enhance the bioavailability of PAHs as well as other hydrophobic organic contaminants (HOCs) by enhancing the desorption during remediation process.

Design of a stability-detecting device for dental implants.

Resonance frequency (RF) analysis technology was used to design a dental implant stability detector. The device uses a miniature-sized electromagnetic triggering rod to elicit vibration in a dental implant. Vibrational signals were recorded via an acoustic receiver. To assess the in vivo performance of the test apparatus, animal models were used. Implants were placed in the left tibia of 12 rabbits using a conventional surgical procedure. Standard 3.2 mm x 8 mm implants were placed in each test tibia with pre-tapping cavities of 3.2 mm and 3.7 mm diameters to simulate either a 'well-fitting' or a 'loosely fitting' situation. The RF values of the test implants were detected by the newly developed device which was directly mounted on the healing abutments of the implants. The results showed that the RF values of the implants under well-fitting conditions significantly increased (p < 0.01) 3 weeks after surgery and reached a plateau at around 6-7 weeks. Meanwhile implants with higher initial RF values had shorter healing times and higher final RF values at the plateau. Based on these findings, it was concluded that the idea of using the current designed device for detecting the degree of bone healing during the osseointegration process seems feasible.

Leptin resistance exacerbates diet-induced obesity and is associated with diminished maximal leptin signalling capacity in rats.

AIMS/HYPOTHESIS: Leptin resistance is generally considered a consequence of obesity. We postulated that leptin resistance is associated with diminished hypothalamic leptin signalling capacity and that leptin resistance is causal to obesity. We assessed maximal leptin-mediated binding of the transcription factor signal transducer and activator of transcription 3 (STAT3), and the response to high-fat feeding in lean leptin-resistant rats. MATERIALS AND METHODS: Recombinant adeno-associated virus encoding rat leptin cDNA (rAAV-leptin) or control vector were administered by intracerebroventricular injection to lean F344 x BN rats for up to 150 days, and food consumption, body weight, serum leptin and glucose tolerance were measured. Leptin-mediated hypothalamic transcription factor binding was assessed at day 150 following an intracerebroventricular injection of 2 mug leptin. Rats pretreated with either control or rAAV-leptin vector for 94 days were given a high-fat diet, and energy intake, body weight gain and adiposity were examined. RESULTS: The rAAV-leptin-treated rats initially responded to leptin gene delivery then became leptin-resistant. They displayed persistent submaximal hypothalamic leptin signalling and enhanced insulin sensitivity, yet maximal hypothalamic signalling capacity was decreased by more than 50%. On a high-fat diet, the leptin-resistant rats consumed more energy, gained more weight and accumulated greater visceral fat mass than controls. CONCLUSIONS/INTERPRETATION: The maximal hypothalamic leptin signalling capacity was diminished in leptin-resistant rats receiving central rAAV-leptin gene therapy. Moreover, this leptin-invoked leptin resistance perturbs the regulation of energy homeostasis in response to high fat exposure, producing augmented energy consumption. This, coupled with potential hypersensitivity to insulin, creates a milieu favouring fat deposition. Our data suggest that leptin resistance is both a consequence and cause of obesity.

Solubilization and desorption of PAHs in soil-aqueous system by biosurfactants produced from Pseudomonas aeruginosa P-CG3 under thermophilic condition.

Surface-active agents (surfactants) can enhance bioremediation of soils contaminated with PAHs by reducing sorption of PAHs or increasing desorption rates. The effectiveness of nonionic surfactant (Tween 80) and biosurfactants to enhance the solubilization and desorption of phenanthrene (Phe) and pyrene (Pyr) in soil-aqueous systems under thermophilic conditions was investigated using batch studies. Tween 80 and biosurfactants produced from Pseudomonas aeruginosa strain, ATCC 9027 and a strain isolated in our laboratory, P-CG3 were tested in this study. The results showed that all the surfactants could effectively enhance the solubility of both Phe and Pyr under thermophilic condition (55 degrees C), which was linearly proportional to the concentrations of surfactants at concentrations above their respective critical micelle concentration (CMC). When the surfactants' concentrations in aqueous phase were above their respective CMCs, substantial amounts of PAHs were desorbed from soil into the aqueous phase. Among the three surfactants used, the biosurfactant produced from our own isolate, P-CG3 was more effective in enhancing the solubilization and desorption of PAHs, implying that it might have the potential to be further applied in the bioremediation of PAH contaminated soils.

Relationships of perceived benefits and barriers to physical activity, physical activity participation and physical fitness in Hong Kong female adolescents.

AIM: Previous studies that examined participation in physical activity suggested that female adolescents were less active compared with males. However, the relationship between physical fitness, physical activity participation, and perceived benefits and barriers for physical activity to adolescents, irrespective of gender, has not been made clear. This study examines the association of these factors in female adolescents. METHODS: Physical activity participation and perceived benefits and barriers to physical activity were determined in 206 secondary school female subjects (aged 11 to 18) using a validated questionnaire. RESULTS: Subjects with a correct concept about optimal physical activity participation to maintain health engaged in an activity level higher than the group without a correct concept (t=2.37, p=0.02). A significant correlation was established between the physical activity participation with "health" (r=0.22, p<0.001) and "body image" (r=0.17, p=0.02) in the perceived benefit category. The individual factor, "make me feel better in general" in the "health" category (p=0.04) and the intention to participate (p<0.001) were shown to be significant predictors for physical activity participation. The combined effects of the regression model explained 35.9% of the variance in participation in physical activity. CONCLUSION: Policies to support regular physical activity participation at school and out-of-school should be strategically developed and promoted, highlighting the promotion of health benefits in exercise and the reinforcement of initial intent towards exercise.

A new siglec family member, siglec-10, is expressed in cells of the immune system and has signaling properties similar to CD33.

The siglecs (sialic acid-binding Ig-like lectins) are a distinct subset of the Ig superfamily with adhesion-molecule-like structure. We describe here a novel member of the siglec protein family that shares a similar structure including five Ig-like domains, a transmembrane domain, and a cytoplasmic tail containing two ITIM-signaling motifs. Siglec-10 was identified through database mining of an asthmatic eosinophil EST library. Using the Stanford G3 radiation hybrid panel we were able to localize the genomic sequence of siglec-10 within the cluster of genes on chromosome 19q13.3-4 that encode other siglec family members. We have demonstrated that siglec-10 is an immune system-restricted membrane-bound protein that is highly expressed in peripheral blood leukocytes as demonstrated by Northern, RT-PCR and flow cytometry. Binding assays determined that the extracellular domain of siglec-10 was capable of binding to peripheral blood leukocytes. The cytoplasmic tail of siglec-10 contains four tyrosines, two of which are embedded in ITIM-signaling motifs (Y597 and Y667) and are likely involved in intracellular signaling. The ability of tyrosine kinases to phosphorylate the cytoplasmic tyrosines was evaluated by kinase assay using wild-type siglec-10 cytoplasmic domain and Y-->F mutants. The majority of the phosphorylation could be attributed to Y597 andY667. Further experiments with cell extracts suggest that SHP-1 interacts with Y667 and SHP-2 interacts with Y667 in addition to another tyrosine. This is very similar to CD33, which also binds the phosphatases SHP-1 and SHP-2, therefore siglec-10, as CD33, may be characterized as an inhibitory receptor.

Comparison of pulmonary arterial flow phenomena in spiral and Lecompte models by computational fluid dynamics.

OBJECTIVES: The transposed great arteries are simply reversed by means of a conventional arterial switch operation with the Lecompte maneuver without resumption of their spiral relationship. We seek to clarify the functional implications of the spiral relationship of the great arteries by means of mathematic modeling. METHODS: Computational fluid dynamics is used to compare flow phenomena of the spiral and Lecompte (nonspiral) models under various body surface areas. RESULTS: The velocity profile and wall-shear stress distribution are more uniform for the spiral than for the Lecompte model. The pressure drop and power loss ratio are smaller for the spiral than the Lecompte model for all the body surface areas investigated. The power loss ratio increases abruptly starting from 0.43 m2 of body surface area for the Lecompte model. At that specific stage, after arterial switch operation with the Lecompte maneuver, suprapulmonary stenoses occur most frequently. CONCLUSIONS: Reconstructing the great arteries in spiral fashion might be recommended because the blood flow patterns are more streamlined than those of the Lecompte maneuver. Initiation of stenosis might be minimized to some extent.