Factors related to prehospital delay and decision delay among acute stroke patients in a district hospital, Malaysia

INTRODUCTION

Time is the greatest challenge in stroke management. This study aimed to examine factors contributing to prehospital delay and decision delay among stroke patients.

MATERIALS AND METHODS

A cross-sectional study involving acute stroke patients admitted to Seri Manjung Hospital was conducted between August 2019 and October 2020 via faceto- face interview. Prehospital delay was defined as more than 120 minutes taken from recognition of stroke symptoms till arrival in hospital, while decision delay was defined as more than 60 minutes taken from recognition of stroke symptoms till decision was made to seek treatment.

RESULTS

The median prehospital delay of 102 enrolled patients was 364 minutes (IQR 151.5, 1134.3) while the median for decision delay was 120 minutes (IQR 30.0, 675.0). No history of stroke (adj. OR 4.15; 95% CI 1.21, 14.25; p=0.024) and unaware of thrombolysis service (adj. OR 17.12; 95% CI 1.28, 229.17; p=0.032) were associated with higher odds of prehospital delay, while Indian ethnicity (adj. OR 0.09; 95% CI 0.02, 0.52; p=0.007) was associated with lower odds of prehospital delay as compared to Malay ethnicity. On the other hand, higher National Institutes of Health Stroke Scale (NIHSS) score (adj. OR 0.86; 95% CI 0.78, 0.95; p=0.002) was associated with lower odds of decision delay.

CONCLUSION

Public awareness is crucial to shorten prehosital delay and decision delay for better patients' outcomes in stroke. Various public health campaigns are needed to improve the awareness for stroke.

Compounds targeting GPI biosynthesis or N-glycosylation are active against Plasmodium falciparum

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Compounds targeting key steps in GPI biosynthesis abrogate P. falciparum growth.

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N-glycosylation disruption halts parasite development and induces delayed death.

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Tunicamycin-induced delayed death is not linked with the synthesis of isoprenoids.

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In summary, two metabolic pathways are outlined for further drug target exploration.

The emergence of resistance to first-line antimalarials, including artemisinin, the last effective malaria therapy in some regions, stresses the urgent need to develop new effective treatments against this disease. The identification and validation of metabolic pathways that could be targeted for drug development may strongly contribute to accelerate this process. In this study, we use fully characterized specific inhibitors targeting glycan biosynthetic pathways as research tools to analyze their effects on the growth of the malaria parasite Plasmodium falciparum and to validate these metabolic routes as feasible chemotherapeutic targets. Through docking simulations using models predicted by AlphaFold, we also shed new light into the modes of action of some of these inhibitors. Molecules inhibiting N-acetylglucosaminyl-phosphatidylinositol de-N-acetylase (GlcNAc-PI de-N-acetylase, PIGL/GPI12) or the inositol acyltransferase (GWT1), central for glycosylphosphatidylinositol (GPI) biosynthesis, halt the growth of intraerythrocytic asexual parasites during the trophozoite stages of the intraerythrocytic developmental cycle (IDC). Remarkably, the nucleoside antibiotic tunicamycin, which targets UDP-N-acetylglucosamine:dolichyl-phosphate N-acetylglucosaminephosphotransferase (ALG7) and N-glycosylation in other organisms, induces a delayed-death effect and inhibits parasite growth during the second IDC after treatment. Our data indicate that tunicamycin induces a specific inhibitory effect, hinting to a more substantial role of the N-glycosylation pathway in P. falciparum intraerythrocytic asexual stages than previously thought. To sum up, our results place GPI biosynthesis and N-glycosylation pathways as metabolic routes with potential to yield much-needed therapeutic targets against the parasite.

Risk factors and outcome of community onset Pseudomonas aeruginosa bacteraemia in two Malaysian district specialist hospitals

INTRODUCTION

Despite the ever-growing number of community onset (CO) Pseudomonas aeruginosa (P. aeruginosa) bacteraemia, there is a dearth of district hospital-based research examining this significant infection, which is associated with high mortality. The objectives of this study were as following: (1) to determine the risk factors of CO P. aeruginosa bacteraemia, (2) to compare the 30-day mortality rate between P. aeruginosa and Escherichia coli bacteraemia and (3) to identify the predictors of 30-day mortality for CO gram negative bacteraemia.

METHODS

This is a retrospective case control study in Hospital Seri Manjung and Hospital Teluk Intan, Perak, Malaysia. P. aeruginosa bacteraemia cases that occurred between 1st January 2015 to 31st December 2019 were included, whilst E. coli bacteraemia cases that occurred within the same period were recruited successively until 1:2 case control ratio was achieved. Subjects below 12-year-old and those with polymicrobial bacteraemia were excluded. Demographic, clinical and treatment data were collected using pre-tested data collection forms by trained investigators.

RESULTS

A total of 61 patients with P. aeruginosa bacteraemia and 122 patients with E. coli bacteraemia were included. Recent admission in the earlier three months, regular haemodialysis, immunosuppressive therapy in the past 30 days, chronic wound/pressure sore at presentation and indwelling urinary catheter at presentation were identified as independent predictors of CO pseudomonal bacteraemia. Whilst older age was identified as a negative predictor of CO Pseudomonal bacteraemia (all p<0.05). The 30-day mortality rate was 34.4% in subjects with P. aeruginosa bacteraemia and 27.0% in those with E. coli bacteraemia (p=0.302). Predictors of 30-day mortality for community onset gram negative bacteraemia were as follow: older age, underlying solid tumours, neutropaenia at presentation, in-patient mechanical ventilation, and inpatient nasogastric tube insertion. Unexpectedly, receipt of inappropriate empirical antibiotics which was switched later (delayed and non-delayed switching) was identified as the negative predictors of mortality (all p<0.05).

CONCLUSION

It is prudent to restrict the usage of empirical anti-pseudomonal antibiotics among individuals at risk as liberal usage of broad-spectrum antibiotics engenders emergence of drug resistant organism, particularly in district setting where community onset pseudomonal bacteraemia remains scarce. Subjects with elevated risk of mortality should receive early escalation of care as per sepsis management guidelines.

Trends in oligomannosylation and α1,2-mannosidase expression in human cancers

Aberrant protein glycosylation is a prominent cancer feature. While many tumour-associated glycoepitopes have been reported, advances in glycoanalytics continue to uncover new associations between glycosylation and cancer. Guided by a comprehensive literature survey suggesting that oligomannosylation (Man_5–9 GlcNAc₂) is a widespread and often regulated glycosignature in human cancers, we here revisit a valuable compilation of nearly 500 porous graphitized carbon LC-MS/MS N-glycomics datasets acquired across 11 human cancer types to systematically test for oligomannose-cancer associations. Firstly, the quantitative glycomics data obtained across 34 cancerous cell lines demonstrated that oligomannosylation is a pan-cancer feature spanning in a wide abundance range. In keeping with literature, our quantitative glycomics data of tumour and matching control tissues and new MALDI-MS imaging data of tissue microarrays showed a strong cancer-associated elevation of oligomannosylation in both basal cell (p = 1.78 × 10^–12) and squamous cell (p = 1.23 × 10^–11) skin cancer and colorectal cancer (p = 8.0 × 10^–4). The glycomics data also indicated that some cancer types including gastric and liver cancer exhibit unchanged or reduced oligomannose levels, observations also supported by literature and MALDI-MS imaging data. Finally, expression data from public cancer repositories indicated that several α1,2-mannosidases are regulated in tumour tissues suggesting that these glycan-processing enzymes may contribute to the cancer-associated modulation of oligomannosylation. This omics-centric study has compiled robust glycomics and enzyme expression data revealing interesting molecular trends that open avenues to better understand the role of oligomannosylation in human cancers.

Pseudomonas aeruginosa bacteraemia: A five-year analysis of epidemiology, clinical profiles, and outcome in a Malaysian district hospital

INTRODUCTION

Pseudomonas aeruginosa is known to be the epitome of nosocomial infections associated with high morbidity and mortality. The dearth of local pseudomonal studies has prompted us to conduct this study with the following objectives: (1) to examine the local pseudomonal bacteraemia (PB) epidemiology and clinical characteristics, (2) to compare the 30-day mortality among PB of different onsets and (3) to determine the predictors of 30-day mortality outcome.

METHODS

This retrospective study was conducted in Hospital Seri Manjung, Perak, Malaysia. All cases of blood culture proven PB that occurred between 1st January 2015 and 31st December 2019 were reviewed. Subjects below 12 year old and whose index blood cultures grew more than one organism were excluded. Demographic, clinical and treatment data were collected using pre-tested data collection forms and analysed using SPSS version 20.0.

RESULTS

Among the 59 subjects included, healthcare associated (HCA) infections were the most prevalent, next to hospital onset (HO) and community onset (CO) infections. The commonest underlying comorbidities were cardiovascular disease, diabetes mellitus, and chronic kidney disease. Respiratory tract was the most frequently implicated source amongst all, while the urinary tract was more frequently implicated as the source of infection among HCA cases. Seventeen patients were admitted to ICU, and they were predominantly from the HO group. Despite having a higher rate of adequate empirical antibiotics administered, the HO group reported the lowest 30-day survival rate. Multiple logistic regression analysis demonstrated the following were independent predictors of 30-day mortality: requiring mechanical ventilator support, requiring central venous line insertion, not requiring surgery, and receiving inappropriate definite antibiotics.

CONCLUSION

The incidence of community onset PB was appreciably low, as cases were predominantly HCA and HO in origin. Significant morbidities were observed among pseudomonal infections, with HO infections portending the worst prognosis. Lastly, prognostic factors for determining the mortality caused by PB depended more on the severity of sepsis than the timeliness of appropriate antibiotics.

A national audit of estimated glomerular filtration rate and proteinuria and the MACD CKD task force recommendations

INTRODUCTION

The Malaysian Association of Clinical Biochemists (MACB) established a Task Force for Chronic Kidney Disease. A survey was undertaken by the Task Force on the reporting of estimated glomerular filtration rate (eGFR) and urine albumin by hospital laboratories in Malaysia in both the government and private sectors.

MATERIALS AND METHODS

An e-mail invitation to participate in an online survey was sent to hospital laboratories in Malaysia (n=140). Questions regarding methods for measuring creatinine, equations for calculating eGFR, eGFR reporting, the terminology used in reporting urine albumin, types of samples and the cut-off values used for normal albuminuria.

RESULTS

A total of 42/140 (30%) laboratories answered the questionnaire. The prevalent method used for serum creatinine measurement was the Jaffé method (88.1%) traceable to isotope-dilution mass spectrometry. eGFR was reported along with serum creatinine by 61.9% of laboratories while 33.3% of laboratories report eGFR on request. The formula used for eGFR reporting was mainly MDRD (64.3%) and results were reported as exact numbers even when the eGFR was <60 ml/min/1.73m². The term microalbumin is still used by 83.3% of laboratories. There is a large heterogeneity among the labs regarding the type of sample recommended for measuring urine albumin, reference interval and reporting units.

CONCLUSION

It is evident that the laboratory assessment of chronic kidney disease in Malaysia is not standardised. It is essential to provide a national framework for standardised reporting of eGFR and urine albumin. Recommendations developed by the MACB CKD Task Force, if adopted by all laboratories, will lead to a reduction in this variability.

Fatal Leptospirosis and Escherichia coli co-infection in a post-partum woman

The occurrence of Leptospirosis and Escherichia coli coinfection in the post-partum period is a novel case. This report illustrated a previously well woman from a suburban area presented with acute neurological deterioration following a two days history of fever during her puerperal period. Early interventions with fluids, broad spectrum antibiotics and intensive supportive care were given. Despite that, she deteriorated rapidly and developed pulmonary hemorrhage, disseminated intravascular coagulopathy, and multi-organ failure. She succumbed within 12 hours of admission. The knowledge about such fatal co-infections should be disseminated to medical practitioners encountering Leptospirosis infection and general public.

Mycobacterium tuberculosis Infection Manipulates the Glycosylation Machinery and the N-Glycoproteome of Human Macrophages and Their Microparticles

Tuberculosis (TB) remains a prevalent and lethal infectious disease. The glycobiology associated with Mycobacterium tuberculosis infection of frontline alveolar macrophages is still unresolved. Herein, we investigated the regulation of protein N-glycosylation in human macrophages and their secreted microparticles (MPs) used for intercellular communication upon M. tb infection. LC-MS/MS-based proteomics and glycomics were performed to monitor the regulation of glycosylation enzymes and receptors and the N-glycome in in vitro-differentiated macrophages and in isolated MPs upon M. tb infection. Infection promoted a dramatic regulation of the macrophage proteome. Most notably, significant infection-dependent down-regulation (4-26 fold) of 11 lysosomal exoglycosidases, e.g., β-galactosidase, β-hexosaminidases and α-/β-mannosidases, was observed. Relative weak infection-driven transcriptional regulation of these exoglycosidases and a stronger augmentation of the extracellular hexosaminidase activity demonstrated that the lysosome-centric changes may originate predominantly from infection-induced secretion of the lysosomal content. The macrophages showed heterogeneous N-glycan profiles and displayed significant up-regulation of complex-type glycosylation and concomitant down-regulation of paucimannosylation upon infection. Complementary intact N-glycopeptide analysis supported a subcellular-specific manipulation of the glycosylation machinery and altered glycosylation patterns of lysosomal N-glycoproteins within infected macrophages. Interestingly, the corresponding macrophage-derived MPs displayed unique N-glycome and proteome signatures supporting a preferential packaging from plasma membranes. The MPs were devoid of infection-dependent N-glycosylation signatures, but interestingly displayed increased levels of the glyco-initiating oligosaccharyltransferase complex and associated α-glucosidases that correlated with increased formation, N-glycan precursor levels and N-glycan density of infected MPs. In conclusion, this system-wide study provides new insight into the host- and pathogen-driven N-glycoproteome manipulation of macrophages in TB.

Adverse effects of young maternal age on neonatal outcomes

INTRODUCTION

Teenage pregnancy is associated with poor neonatal outcomes, which may burden the young mothers and their families. The aim of this study was to determine the effect young maternal age and single motherhood has on neonatal outcomes.

METHODS

We conducted a retrospective cohort study of 267 infants born to mothers aged ≤ 21 years in National University Hospital, Singapore, from January 2011 to December 2012. We compared the maternal demographics and neonatal outcomes of single mothers with those of married mothers. The neonatal outcomes of our study cohort were also compared to the hospital's birth cohort during the same period.

RESULTS

Unsatisfactory antenatal care was more prevalent among the young single mothers than among the young married mothers (odds ratio [OR] 2.90, 95% confidence interval [CI] 1.71-4.92, p < 0.01). The infants of the young single mothers had a lower mean birth weight (p = 0.01), with a significant proportion weighing < 2.5 kg (OR 2.91, 95% CI 1.35-6.37, p < 0.01). Young maternal age was linked to a higher incidence of prematurity (OR 1.70, 95% CI 1.18-2.43, p < 0.01), major congenital defects (OR 4.68, 95% CI 2.10-10.13, p < 0.01), and a perinatal mortality of 18.7 per 1,000 births (OR 3.76, 95% CI 1.26-10.32, p = 0.02).

CONCLUSION

Young single mothers were more likely to have unsatisfactory antenatal care and lighter infants. Young maternal age was associated with a higher risk of prematurity, major congenital malformations and perinatal mortality. More studies are needed to ascertain the cause of these adverse outcomes.

Integrated Proteomic and Genomic Analysis of Gastric Cancer Patient Tissues

V-erb-b2 erythroblastic leukemia viral oncogene homologue 2, known as ERBB2, is an important oncogene in the development of certain cancers. It can form a heterodimer with other epidermal growth factor receptor family members and activate kinase-mediated downstream signaling pathways. ERBB2 gene is located on chromosome 17 and is amplified in a subset of cancers, such as breast, gastric, and colon cancer. Of particular interest to the Chromosome-Centric Human Proteome Project (C-HPP) initiative is the amplification mechanism that typically results in overexpression of a set of genes adjacent to ERBB2, which provides evidence of a linkage between gene location and expression. In this report we studied patient samples from ERBB2-positive together with adjacent control nontumor tissues. In addition, non-ERBB2-expressing patient samples were selected as comparison to study the effect of expression of this oncogene. We detected 196 proteins in ERBB2-positive patient tumor samples that had minimal overlap (29 proteins) with the non-ERBB2 tumor samples. Interaction and pathway analysis identified extracellular signal regulated kinase (ERK) cascade and actin polymerization and actinmyosin assembly contraction as pathways of importance in ERBB2+ and ERBB2- gastric cancer samples, respectively. The raw data files are deposited at ProteomeXchange (identifier: PXD002674) as well as GPMDB.

Comprehensive N-glycome profiling of cultured human epithelial breast cells identifies unique secretome N-glycosylation signatures enabling tumorigenic subtype classification

The secreted cellular sub-proteome (secretome) is a rich source of biologically active glycoproteins. N-Glycan profiling of secretomes of cultured cancer cells provides an opportunity to investigate the link between protein N-glycosylation and tumorigenesis. Utilizing carbon-LC-ESI-CID-MS/MS of protein released native N-glycans, we accurately profiled the secretome N-glycosylation of six human epithelial breast cells including normal mammary epithelial cells (HMEC) and breast cancer cells belonging to luminal A subtype (MCF7), HER2-overexpressing subtype (SKBR3), and basal B subtype (MDA-MB157, MDA-MB231, HS578T). On the basis of intact molecular mass, LC retention time, and MS/MS fragmentation, a total of 74 N-glycans were confidently identified and quantified. The secretomes comprised significant levels of highly sialylated and fucosylated complex type N-glycans, which were elevated in all cancer cells relative to HMEC (57.7-87.2% vs 24.9%, p < 0.0001 and 57.1-78.0% vs 38.4%, p < 0.0001-0.001, respectively). Similarly, other glycan features were found to be altered in breast cancer secretomes including paucimannose and complex type N-glycans containing bisecting β1,4-GlcNAc and LacdiNAc determinants. Subtype-specific glycosylation were observed, including the preferential expression of α2,3-sialylation in the basal B breast cancer cells. Pathway analysis indicated that the regulated N-glycans were biosynthetically related. Tight clustering of the breast cancer subtypes based on N-glycome signatures supported the involvement of N-glycosylation in cancer. In conclusion, we are the first to report on the secretome N-glycosylation of a panel of breast epithelial cell lines representing different subtypes. Complementing proteome and lipid profiling, N-glycome mapping yields important pieces of structural information to help understand the biomolecular deregulation in breast cancer development and progression, knowledge that may facilitate the discovery of candidate cancer markers and potential drug targets.

Comparative studies of the proteome, glycoproteome, and N-glycome of clear cell renal cell carcinoma plasma before and after curative nephrectomy

Clear cell renal cell carcinoma is the most prevalent of all reported kidney cancer cases, and currently there are no markers for early diagnosis. This has stimulated great research interest recently because early detection of the disease can significantly improve the low survival rate. Combining the proteome, glycoproteome, and N-glycome data from clear cell renal cell carcinoma plasma has the potential of identifying candidate markers for early diagnosis and prognosis and/or to monitor disease recurrence. Here, we report on the utilization of a multi-dimensional fractionation approach (12P-M-LAC) and LC–MS/MS to comprehensively investigate clear cell renal cell carcinoma plasma collected before (disease) and after (non-disease) curative nephrectomy (n = 40). Proteins detected in the subproteomes were investigated via label-free quantification. Protein abundance analysis revealed a number of low-level proteins with significant differential expression levels in disease samples, including HSPG2, CD146, ECM1, SELL, SYNE1, and VCAM1. Importantly, we observed a strong correlation between differentially expressed proteins and clinical status of the patient. Investigation of the glycoproteome returned 13 candidate glycoproteins with significant differential M-LAC column binding. Qualitative analysis indicated that 62% of selected candidate glycoproteins showed higher levels (upregulation) in M-LAC bound fraction of disease samples. This observation was further confirmed by released N-glycans data in which 53% of identified N-glycans were present at different levels in plasma in the disease vs non-disease samples. This striking result demonstrates the potential for significant protein glycosylation alterations in clear cell renal cell carcinoma cancer plasma. With future validation in a larger cohort, information derived from this study may lead to the development of clear cell renal cell carcinoma candidate biomarkers.

Community-based wastewater treatment systems and water quality of an Indonesian village

This paper examines the impact of community-based water treatment systems on water quality in a peri-urban village in Yogyakarta, Indonesia. Water samples were taken from the wastewater treatment plants (WWTPs), irrigation canals, paddy fields and wells during the dry and wet seasons. The samples were tested for biological and chemical oxygen demand, nutrients (ammonia, nitrate, total nitrogen and total phosphorus) and Escherichia coli. Water quality in this village is affected by the presence of active septic tanks, WWTP effluent discharge, small-scale tempe industries and external sources. We found that the WWTPs remove oxygen-demanding wastes effectively but discharged nutrients, such as nitrate and ammonia, into irrigation canals. Irrigation canals had high levels of E. coli as well as oxygen-demanding wastes. Well samples had high E. coli, nitrate and total nitrogen levels. Rainfall tended to increase concentrations of biological and chemical oxygen demand and some nutrients. All our samples fell within the drinking water standards for nitrate but failed the international and Indonesian standards for E. coli. Water quality in this village can be improved by improving the WWTP treatment of nutrients, encouraging more villagers to be connected to WWTPs and controlling hotspot contamination areas in the village.

An optimized approach for enrichment of glycoproteins from cell culture lysates using native multi-lectin affinity chromatography

Lectins are capable of recognizing specific glycan structures and serve as invaluable tools for the separation of glycosylated proteins from nonglycosylated proteins in biological samples. We report on the optimization of native multi-lectin affinity chromatography, combining three lectins, namely, concanavalin A, jacalin, and wheat germ agglutinin for fractionation of cellular glycoproteins from MCF-7 breast cancer lysate. We evaluated several conditions for optimum recovery of total proteins and glycoproteins such as low pH and saccharide elution buffers, and the inclusion of detergents in binding and elution buffers. Optimum recovery was observed with overnight incubation of cell lysate with lectins at 4°C, and inclusion of detergent in binding and saccharide elution buffers. Total protein and bound recoveries were 80 and 9%, respectively. Importantly, we found that high saccharide strength elution buffers were not necessary to release bound glycoproteins. This study demonstrates that multi-lectin affinity chromatography can be extended to total cell lysate to investigate the cellular glycoproteome.

Proteogenomic analysis of human colon carcinoma cell lines LIM1215, LIM1899, and LIM2405

As part of the genome-wide and chromosome-centric human proteomic project (C-HPP), we have integrated shotgun proteomics approach and a genome-wide transcriptomic approach (RNA-Seq) of a set of human colon cancer cell lines (LIM1215, LIM1899 and LIM2405) that were selected to represent a wide range of pathological states of colorectal cancer. The combination of a standard proteomics approach (1D-gel electrophoresis coupled to LC/ion trap mass spectrometry) and RNA-Seq allowed us to exploit the greater depth of the transcriptomics measurement (∼ 9800 transcripts per cell line) versus the protein observations (∼ 1900 protein identifications per cell line). Conversely, the proteomics data were helpful in identifying both cancer associated proteins with differential expression patterns as well as protein networks and pathways which appear to be deregulated in these cell lines. Examples of potential markers include mortalin, nucleophosmin, ezrin, LASP1, alpha and beta forms of spectrin, exportin, the carcinoembryonic antigen family, EGFR and MET. Interaction analyses identified the large intermediate filament family, the protein folding network and adapter proteins in focal adhesion networks, which included the CDC42 and RHOA signaling pathways that may have potential for identifying phenotypic states representing poorly and moderately differentiated states of CRC, with or without metastases.

New therapies for chronic hepatitis C infection: a systematic review of evidence from clinical trials

INTRODUCTION

Hepatitis C virus (HCV) affects approximately 3% of the world population. The current standard of care for treatment of HCV is a combination of pegylated interferon and ribavirin. Approximately 10% of patients will stop treatment and 30% of patients require dose reduction because of side effects. For genotype 1 HCV-infected patients, only 40% of patients will achieve undetectable viral load 26 weeks posttreatment.

AIMS

The objectives of this review were to identify new treatments that are in clinical trials. These include boceprevir and telaprevir which are in routine clinical use and form part of the American Association for the Study of Liver Diseases (AASLD) 2011 guidelines as well as drugs based on observational studies, improving/modifying ribavirin or interferon-based therapies, modifying the host response and finally the use of direct-acting antiviral agents (DAA).

MATERIALS AND METHODS

  MEDLINE and EMBASE databases were searched from 2008 to 2011 for treatments for hepatitis C. Furthermore, abstracts and poster presentations for the annual European Association Study of the Liver, AASLD, Digestive Disease Week and Asian Pacific Association for the study of the Liver were searched for relevant material.

RESULTS

All four classes of DAA; NS3/NS4a serine protease inhibitors, cyclophilin inhibitors, NS5b polymerase inhibitors and NS5a inhibitors, show good success rates. Trials have been performed without ribavirin or interferon and demonstrate good antiviral activity with a decreased side effect profile. Combinations of DAA are a promising area of research with a high success rate.

CONCLUSIONS

Clinical trials show that future HCV therapy could be personalised, achieve higher success rates with decreased adverse incidents.

Evaluation of carbon-based nanosorbents synthesised by ethylene decomposition on stainless steel substrates as potential sequestrating materials for nickel ions in aqueous solution

The present work covers the preparation of carbon-based nanosorbents by ethylene decomposition on stainless steel mesh without the use of external catalyst for the treatment of water containing nickel ions (Ni2+). The reaction temperature was varied from 650 to 850 degrees C, while reaction time and ethylene to nitrogen flow ratio were maintained at 30 min and 1:1 cm3/min, respectively. Results show that nanosorbents synthesised at a reaction temperature of 650 degrees C had the smallest average diameter (75 nm), largest BET surface area (68.95 m2/g) and least amount of impurity (0.98 wt.% Fe). A series of batch-sorption tests were performed to evaluate the effects of initial pH, initial metal concentration and contact time on Ni2+ removal by the nanosorbents. The equilibrium data fitted well to Freundlich isotherm. The kinetic data were best correlated to a pseudo second-order model indicating that the process was of chemisorption type. Further analysis by the Boyd kinetic model revealed that boundary layer diffusion was the controlling step. This primary study suggests that the prepared material with Freundlich constants compared well with those in the literature, is a promising sorbent for the sequestration of Ni2+ in aqueous solutions.

A qualitative study on HPV vaccination from a nursing perspective in Hong Kong

OBJECTIVE

To identify the perception on human papillomavirus (HPV) vaccination among female nursing students in Hong Kong.

DATA SOURCES

Data were collected through focus group discussions and semi-structured in-depth interviews. All participants (n=28) were female nursing students of a university in Hong Kong. Tape recordings of individual interviews and focus group discussions were transcribed verbatim in Chinese, translated into English, and analyzed according to Colaizzi's phenomenological analysis.

STUDY DESIGN

Four major themes emerged from the data: nursing students' understanding about HPV vaccine, nursing students' attitude on HPV vaccine, nursing students' perspective on HPV vaccination promotion, and nursing role on HPV vaccination.

CONCLUSIONS

Government should take initiative in promotion with vaccine suppliers. The awareness and knowledge of HPV and HPV vaccination among women should be increased in order to raise the positive attitude of women towards HPV vaccination and prevention of cervical cancer. Health professionals should work together on HPV promotion among women and increase the HPV vaccination rates. Moreover, further studies regarding attitude and awareness of HPV vaccination among women in different age groups are needed in order to identify more associated factors affecting their perceptions towards HPV vaccination.

Role of autophagy in protection afforded by hypoxic preconditioning against MPP+-induced neurotoxicity in SH-SY5Y cells

A sublethal preconditioning has been proposed as a neuroprotective strategy against several CNS neurodegenerative diseases. In this study, the involvement of autophagy in the protection provided by hypoxic preconditioning against 1-methyl-4-phenylpyridinium (MPP(+))-induced neurotoxicity was studied in SH-SY5Y neuroblastoma cells. In contrast to the cytotoxicity of 0.1% oxygen, 1% oxygen hypoxia for 24h did not cause significant cell death. A transient increase in LC3-II level, a biomarker of autophagy, was demonstrated during hypoxic treatment. At the same time, 8-h hypoxia increased fluorescence due to monodansylcadaverine, a specific dye for autophagosomes, in the treated cells. Co-incubation with bafilomycin A1 (10 nM) further increased hypoxia-induced LC3-II levels but 3-methyladenine (3-MA; 10 mM) reduced the elevation in LC3-II levels induced by 8-h hypoxia. Moreover, 8-h hypoxia increased free radical formation and nuclear HIF-1alpha level. Glutathione was found to diminish hypoxia-induced LC3-II elevation. In contrast to the elevated LC3-II level, 8-h hypoxia significantly decreased mitochondrial mass. Furthermore, a rebound elevation in mitochondrial mass was observed under 8-h hypoxia and subsequent 12-h normoxia. Prior hypoxia attenuated the MPP(+)-induced elevation in LC3-II levels and cell death. Moreover, hypoxic pretreatment inhibited MPP(+)-induced activation of caspase-3 and DNA fragmentation. Co-incubation with 3-MA during hypoxia prevented the protection afforded by hypoxic preconditioning against MPP(+)-induced increases in LC3-II levels and neurotoxicity. Taken together, our results suggest that sublethal hypoxia induces autophagy that is mediated by oxidative stress. Furthermore, autophagy may be involved in the protection provided by hypoxic preconditioning against MPP(+)-induced neurotoxicity, indicating a neuroprotective role of autophagy in hypoxic preconditioning.

UGT1A1 haplotype mutation among Asians in Singapore

BACKGROUND

The uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) enzyme is responsible for conjugation of the bilirubin in the liver as well as for drug metabolism. Some of the polymorphisms have been associated with an increased risk of neonatal hyperbilirubinemia which may explain the increased incidence of jaundice in an Asian population as well as exaggerated irinotecan-induced leukopenia.

OBJECTIVE

The local Asian incidence of hypomorphic haplotypes, defined as gene mutations known to have a reduced function, has not been described. Clinical correlation between the mutations and the need for phototherapy for hyperbilirubinemia was carried out.

METHODS

A cohort of 241 consecutive term infants delivered in the National University Hospital, Singapore, was recruited with parental consent. Cord blood was collected, and the promoter and coding regions of the UGT1A1 gene were sequenced.

RESULTS

Six known haplotypes and 2 novel haplotypes were identified: 1 wild type, 5 with reduced function, while the 2 novel ones were predicted to have decreased function. The frequency of these hypomorphic haplotypes was high. Among the 241 infants screened, 35% had 1 hypomorphic haplotype and 12% had 2 hypomorphic haplotypes. The frequency was also different among ethnic groups, with 48% Chinese, 64% Indian and 31% Malay infants having at least 1 hypomorphic haplotype (chi(2) test, p < 0.05). There was a trend seen between the number of G71R mutations and the need for phototherapy (chi2 test for trend, p < 0.05).

CONCLUSIONS

The local Asian incidence of hypomorphic haplotypes was high and there was a trend between the number of G71R mutations and the need for phototherapy. The G71R mutation may account for the increased incidence of neonatal jaundice seen in Asian populations.

Simultaneous ammonium-nitrogen and copper removal, and copper recovery using nitrifying biofilm from the ultra-compact biofilm reactor

Simultaneous ammonium-nitrogen (NH(4)(+)-N) and copper removal, and copper recovery in synthetic wastewater using nitrifying biofilm from an ultra-compact biofilm reactor (UCBR) was demonstrated in batch studies, which consisted of three phases: Phase 1 for NH(4)(+)-N and copper removals, Phase 2 for copper recovery, and Phase 3 for NH(4)(+)-N removal. The results showed that more than 96.3% of copper was removed within 60min, while 60.1% of the adsorbed copper was recovered through rinsing the biofilms with 0.1mM of ethylenediaminetetraacetic acid (EDTA). The nitrifying biofilm was able to adsorb 0.245mg of copper/g of biofilms. After recovery treatment, 29.4% of copper remained bound within the nitrifying biofilms. No significant inhibitory effects towards NH(4)(+)-N removal in the presence of 0.92mg copper/L was noted in Phase 1 compared with the control test. However, lower initial pH condition in the recovery process and the accumulation of copper on the biofilm led to 50% inhibition on NH(4)(+)-N removal efficiency in the subsequent phase.

Treatment of RO brine-towards sustainable water reclamation practice

Treatment and disposal of RO brine is an important part in sustaining the water reclamation practice. RO brine generated from water reclamation contains high concentration of organic and inorganic compounds. Cost-effective technologies for treatment of RO brine are still relatively unexplored. Thus, this study aim to determine a feasible treatment process for removal of both organic and inorganic compounds in RO brine generated from NEWater production. The proposed treatment consists of biological activated carbon (BAC) column followed by capacitive deionization (CDI) process for organic and inorganic removals, respectively. Preliminary bench-scale study demonstrated about 20% TOC removal efficiency was achieved using BAC at 40 mins empty bed contact time (EBCT) while the CDI process was able to remove more than 90% conductivity reducing it from 2.19 mS/cm to only about 164 microS/cm. More than 90% cations and anions in the BAC effluent were removed using CDI process. In addition, TOC and TN removals of 78% and 91%, respectively were also attained through this process. About 90% water recovery was achieved. This process shows the potential of increased water recovery in the reclamation process while volume for disposal can be further minimized. Further studies on the sustainable operation and process optimization are ongoing.

Novel brain reactive autoantibodies: Prevalence in systemic lupus erythematosus and association with psychoses and seizures

Autoantibodies can cause neuropsychiatric manifestations in lupus patients by altering the physiological function of neuronal cells. In this study, we identified Brain Reactive Autoantibodies (BRAAs) against murine neuronal membrane proteins (M.W. 27.5 and 29.5 kD) and found them correlating with psychosis and/or seizures in lupus patients. They were specific to neuronal membrane tissues of mammalian origin and are significantly associated with psychosis and/or seizures (p<0.0001). These membrane proteins mass spectrometry profiles did not match to any published protein sequences. These BRAAs may play important roles in the pathophysiology of neuropsychiatric lupus.

PCR-RFLP genotyping for exon 1 and promoter region mutations of the human mannose binding lectin (MBL-2) gene

The Mannose Binding Lectin (MBL) plays an important role in innate immunity and its genetic deficiencies are associated with frequent and prolonged infections. Serum MBL determination may not accurately detect acute phase protein levels and it is also difficult to detect dysfunctional protein. Genotyping of the exon 1 and promoter regions in the MBL gene will provide useful information on the presence of deficiencies in patients. A reproducible PCR-RFLP method is described to accurately detect genotypes of exon 1 and polymorphic haplotypes of the promoter region in the MBL gene.

Development of an integrated membrane process for water reclamation

An integrated membrane process (IMP) comprising a membrane bioreactor (MBR) and a reverse osmosis (RO) process was developed for water reclamation. Wastewater was treated by an MBR operated at a sludge retention time (SRT) of 20 days and a hydraulic retention time (HRT) of 5.5 h. The IMP had an overall recovery efficiency of 80%. A unique feature of the IMP was the recycling of a fraction of RO concentrate back to the MBR. Experimental results revealed that a portion of the slow- and hard-to-degrade organic constituents in the recycle stream could be degraded by an acclimated biomass leading to an improved MBR treatment efficiency. Although recycling concentrated constituents could impose an inhibitory effect on the biomass and suppress their respiratory activities, results obtained suggested that operating MBR (in the novel IMP) at an F/M ratio below 0.03 g TOC/g VSS.day could yield an effluent quality comparable to that achievable without concentrate recycling. It is noted in this study that the novel IMP could achieve an average overall TOC removal efficiency of 88.940% and it consistently produced product water usable for high value reuse applications.

Biofilm morphology and nitrification activities: recovery of nitrifying biofilm particles covered with heterotrophic outgrowth

Biofilm processes are commonly used for nitrification. Operationally, a whitish heterotrophic biofilm layer tends to develop onto nitrifying biofilm when it has been exposed to organic carbon-containing wastewater for a prolonged period. The development of a heterotrophic biofilm layer could lead to deterioration in nitrification activities and biofilm morphology. The recovery characteristics, in terms of biofilm morphology and nitrification activities, of deteriorated biofilm particles (i.e. nitrifying biofilm particles covered with heterotrophic outgrowth) were investigated by transferring the deteriorated biofilm particles (from an Ultra-Compact Biofilm Reactor (UCBR) which was part of a packed bed-UCBR system used for treating organic carbon and ammonia-containing wastewater) to a UCBR fed solely with ammonia wastewater (referred to as 'Recovery-UCBR'). At a hydraulic retention time (HRT) of 8.7 h and a sand-carrier concentration of 4.0% (v/v), density of the outer heterotrophic biofilm layer reduced progressively which led to subsequent detachment of this layer from the nitrifying biofilm particles. As a result, morphology of the nitrifying biofilm improved gradually in the Recovery-UCBR. A stable nitrification rate of up to 1.74 kg NH4+-N/m3 d was obtained in the Recovery-UCBR.

Two-stage SBR for treatment of oil refinery wastewater

A two-stage sequencing batch reactor (SBR) system was used for treatment of oily wastewater with COD and oil and grease (O&G) concentrations ranging from 1,722-7,826 mg/L and 5,365-13,350 mg/L, respectively. A suitable start-up protocol was developed using gradual increase in oily wastewater composition with methanol as the co-substrate. This strategy enabled a short acclimation period of 12 days for the sludge in the two-stage SBR to adapt to the oily wastewater. After acclimation, the 1st stage and 2nd stage SBRs were able to achieve COD removals of 47.0+/-2.4% and 95.3+/-0.5%, respectively. The 1st stage SBR was able to achieve 99.8+/-0.1% of O&G removal and effluent O&G from the 1st stage SBR was only 6+/-2 mg/L. The 2nd stage SBR was used to further remove COD in the effluent from the 1st stage SBR. The final effluent from the 2nd stage SBR had a COD concentration of 97+/-16 mg/L with no detectable O&G content. Thus, a two-stage SBR system was shown to be feasible for treating high strength oily wastewater to meet the local discharge standards.

Removal of MS2 bacteriophage using membrane technologies

Removals of MS2 bacteriophage virus using different membrane materials under different operating pressures were investigated. The results obtained in this study suggested that a better log removal in terms of MS2 bacteriophage virus could be achieved using Polyamide RO membrane under the optimum operating pressure of 100 psi. It is further noted that variable MS2 influent concentration levels resulted in corresponding variable log removals of the bacteriophages by the Polyamide RO membrane. The presence of MS2 bacteriophage virus in the effluent could possibly be due to leakage of bacteriophages through the membranes structure. Investigations using SEM and AFM showed that there were gaps or pores present in the membrane structure which were sufficiently large for the MS2 viruses to pass through.

Influence of age on the presentation and outcome of acidotic and hyperosmolar diabetic emergencies

BACKGROUND

Diabetic emergencies associated with ketoacidosis (DKA) and a hyperosmolar, hyperglycaemic state (HHS) are both acute life-threatening metabolic disturbances. Traditionally, DKA and HHS have been classified as distinct entities but there is evidence to suggest that patients can present with elements of both conditions.

AIMS

To examine the presentation profiles, mortality rates and prognostic factors associated with a fatal outcome for diabetic patients admitted with ketoacidosis and/or hyperosmolarity.

METHODS

A retrospective analysis of 312 admissions to an Australian tertiary referral hospital between 1986 and 1999.

RESULTS

Of the patients surveyed, DKA was the diagnosis for 171 presentations (55%), HHS was the diagnosis for 47 presentations (15%) and combined DKA and HHS (DKA-HHS) was diagnosed for 94 presentations (30%). Age at presentation for DKA patients (33+/-1.2 years) was significantly less (P< 0.01) than DKA-HHS patients (44+/-2.4 years). This, in turn, was significantly less (P < 0.01) than HHS patients (69+/-1.7 years). There were 15 deaths for the 312 presentations, resulting in an overall mortality rate of 4.8%. Combined mortality rates according to age at presentation were: (i) 0/134 for patients aged <35 years, (ii) 1/85 (1.2%) for patients aged 35-55 years and (iii) 14/93 (15.0%) for patients aged >55 years. For the three categories of diabetic emergencies, mortality rates were: (i) 2/171 (1.2%) for DKA, (ii) 5/94 (5.3%) for DKA-HHS and (iii) 8/47 (17%) for HHS. For all presentations associated with ketoacidosis - regardless of the degree of hyperosmolarity - the mortality rate was 7/264 (2.7%), however for all presentations with hyperosmolarity regardless of the degree of acidosis - the mortality rate was 13/141 (9.2%). When the associations between age, category of diabetic emergency, serum osmolarity and various other biochemical parameters with mortality were assessed by logistic regression analysis, age and the degree of hyperosmolarity were found to be the most powerful predictors of a fatal outcome. In particular, patients aged >65 years presenting with a serum osmolarity >375 mOsmol/L were at greatest risk. However, in a multivariate analysis only age emerged as a significant independent predictor of mortality (P < 0.01).

CONCLUSIONS

The mixed state of ketoacidosis and hyperosmolarity was observed in 30% of presentations for diabetic hyperglycaemic emergencies. Although age and degree of hyperosmolarity both influenced mortality rates, only age was found to be an independent predictor of mortality. The mortality rate for diabetic emergencies associated with ketoacidosis remained low, in keeping with other studies. By contrast, the mortality rate for diabetic emergencies associated with a hyperosmolar state remained considerably higher. This higher mortality will most likely persist because deaths associated with a hyperosmolar state were in elderly patients with significant comorbidity.

Toxicity assays to determine the start-up strategy for an anaerobic sequencing batch reactor (anSBR)

Addition of glucose as the co-substrate and the use of a water-based polymer to enhance granulation were studied with the aim of shortening the start-up period of an anSBR (anerobic sequencing batch reactor) for high-strength industrial wastewater treatment. An initial start-up feed composition consisting of 70% sucrose and 30% industrial wastewater was favorable to reduce the start-up time. Increase in the average particle size and reduction in settled supernatant turbidity was observed with increased water-based polymer addition up to a concentration of 0.1 m/L. Polymer dosages above 0.1 ml/L were undesirable as big and "flaky" flocs were formed which prevented the flocs from settling quickly. Addition of 0.005 ml/L to 0.1 ml/L polymer to the mixed liquor had no observable adverse effects on the anaerobic biomass metabolism. Instead, the addition of the polymer appeared to improve biogas production and had an overall positive effect on anSBR performance treating the industrial wastewater.

Packed bed columns for high rate nitrogen and carbon removals

Two packed bed column (PB) systems, namely anoxic-anoxic and anoxic-oxic were investigated for treatment of wastewater containing high concentrations of nitrogen (N) and COD. The anoxic-anoxic PB removal rates 6.70 kg N/m3 x d and 26.02 kg COD/m3 x d, respectively. The responding removal rates of the anoxic-oxic PB system were 7.41 kg N/m3 and 28.00 kg COD/m3 x d, respectively. The N and COD removal efficiencies of anoxic anoxic PB system were in the range of 99.2-100% and 97.2-98.8%, respectively. The corresponding removal efficiencies of anoxic-oxic PB system were 97.5-100% and 98.6-99.4%, respectively. These findings showed that a PB system consisting of anoxic-oxic columns in series has a high capacity to remove nitrogenous and carbonaceous compounds even though the influent to the anoxic stage was oxygenated. Better system stability in terms of denitrification was, however, obtained with the anoxic-anoxic system.

Hypersensitivity of pulmonary C fibre afferents induced by cationic proteins in the rat

1. Airway administration of synthetic cationic proteins, poly-L-lysine (PLL) and poly-L-arginine (PLA), is known to induce bronchial hyper-responsiveness, and an involvement of bronchopulmonary C fibre activation has been suggested. In this study we investigated the effects of PLL and PLA on single-unit pulmonary vagal C fibre afferents in anaesthetized, open-chest rats. 2. Intratracheal (I.T.) instillation of PLL or PLA activated C fibre endings in a dose-dependent manner; for example, a high dose of PLL (50 microg in 0.1 ml) had a sporadic but intense stimulatory effect on these afferents. The augmented C fibre activity slowly declined but remained elevated even after 120 min. 3. Intratracheal instillation of PLL or PLA greatly enhanced the sensitivities of pulmonary C fibres to both lung inflation and chemical stimuli (e.g. capsaicin); for example, the change in fibre activity in response to constant-pressure lung inflation (tracheal pressure (P(t)) = 30 cmH(2)O; 10 s duration) increased by approximately 6-fold after PLL instillation. 4. When administered by intravenous injection or instilled into a different region of the lung, PLL or PLA, even at a higher dose, failed to have any effect on the C fibre endings. 5. The stimulatory and sensitizing effects of PLL or PLA were completely nullified when their cationic charges were neutralized with low molecule weight heparin. 6. In conclusion, I.T. instillation of synthetic cationic proteins causes an intense stimulatory effect on pulmonary C fibres and potentiates their sensitivities to both lung inflation and chemical stimuli. These effects are probably generated by an interaction between the cationic charges carried by these proteins and the airway mucosa.

Exploring factors influencing Chinese women's decision to have elective caesarean surgery

OBJECTIVES

to identify the factors that influence Hong Kong Chinese women's decision to have an elective caesarean section. To explore Chinese women's perceptions of their autonomous involvement in childbirth decision-making.

DESIGN

a qualitative exploratory design.

SETTING

a postnatal ward of a private hospital in Hong Kong.

PARTICIPANTS

a purposive sample of six postnatal women who had undergone an elective caesarean section.

FINDINGS

four thematic categories were identified including: avoiding fetal and maternal risks, exercising autonomy to make an independent choice, Chinese belief systems, and rejoicing and regretting.

KEY CONCLUSIONS AND IMPLICATIONS FOR PRACTICE

we propose the provision of a 'named' midwife and continuity of care. Improving the availability of information on caesarean sections, accommodating a Chinese belief system in the planning of midwifery services at the international level and establishing post caesarean section peer support groups are recommended.

Retrospective analysis of mortalities associated with medication errors

The types, causes, contributing factors, and patient demographics of fatal medication errors were reviewed. Case reports of medication errors from hospitals, ambulatory care settings, and patients' homes that were entered in FDA's Adverse Event Reporting System during 1993-98 were the source of information on fatal medication errors. Each report was classified using predefined criteria and a taxonomy developed by the National Coordinating Council for Medication Error Reporting and Prevention. The types, causes, contributing factors, and patient demographics were identified, and the causality of each case was assessed to prevent future fatalities. The data indicated 5,366 medication error reports. Fifty-nine reports were excluded and classified as duplicate reports or intentional overdoses. Of the remaining medication error reports, 68.2% resulted in serious patient outcomes and 9.8% were fatal. Of the 469 fatal medication error reports, 48.6% occurred in patients over 60 years. The most common types of errors resulting in patient death involved administering an improper dose (40.9%), administering the wrong drug (16%), and using the wrong route of administration (9.5%). The most common causes of errors were performance and knowledge deficits (44%) and communication errors (15.8%). Fatal medication errors accounted for approximately 10% of medication errors reported to FDA and were most frequently the result of improper dosing of the intended drug and administration of an incorrect drug. A review of case reports of medication errors from 1993 to 1998 yielded information on the most frequent causes of and contributing factors involved in fatal medication errors.

Chronic smoking enhances tachykinin synthesis and airway responsiveness in guinea pigs

This study tests the hypothesis that the bronchial hyperreactivity induced by chronic cigarette smoke (CS) exposure involves the increased expression and release of tachykinins and calcitonin gene-related peptide (CGRP) from afferent nerve fibers innervating the airways. In guinea pigs chronically exposed to CS (20 min twice daily for 14-17 d), peak response in total lung resistance to capsaicin (1.68 microg/kg, intravenously) was significantly greater than that evoked by the same dose of capsaicin in control (air-exposed) animals. This augmented response in CS-exposed animals was abolished after treatment with CP-99994 and SR-48968, the neurokinin (NK)-1 and NK-2 receptor antagonists, suggesting the involvement of tachykinins in chronic CS-induced airway hyperresponsiveness (AHR). Further, substance P (SP)-like immunoreactivity (LI) and CGRP-LI in the airway tissue were significantly greater in the CS animals than in the control animals. Finally, beta-preprotachykinin (PPT, a splice variant from the PPT A gene encoding tachykinins including SP and NKA) messenger RNA levels as measured by in situ hybridization histochemistry displayed a significant increase in jugular ganglion neurons but not in dorsal root or nodose ganglion neurons. These data suggest that chronic CS-induced AHR is related to an increase in SP synthesis and release in jugular ganglion neurons innervating the lungs and airways.

Transmyocardial laser revascularization dose response: enhanced perfusion in a porcine ischemia model as a function of channel density

BACKGROUND

Transmyocardial laser revascularization (TMR) appears to provide symptomatic relief to patients with ischemic heart disease, but evidence that TMR enhances perfusion to ischemic myocardium remains limited. Furthermore, it is uncertain whether there exists a TMR dose-response relationship that is a function of channel number. We therefore compared restoration of blood flow as analyzed by rest and stress 99mTc-sestamibi scans and histologic grading of neovascularization after 50-channel, 25-channel, or 10-channel TMR using the excimer laser in an established model of porcine myocardial ischemia.

METHODS

Yorkshire swine underwent a thoracotomy and placement of an ameroid constrictor around the proximal circumflex coronary artery. Three weeks later, the animals underwent resting and adenosine stress 99mTc-sestamibi scans for evaluation of ischemia immediately before repeat thoracotomy and TMR with either 50 channels (n = 4), 25 channels (n = 4), or 10 channels (n = 4) in the circumflex territory. The animals underwent repeat perfusion analyses 4 weeks later, after which the animals were sacrificed and the hearts were perfusion fixed for histologic evaluation of neovascularization.

RESULTS

All animals survived to sacrifice. Semiquantitative analyses of the sestamibi perfusion scans 4 weeks after lasing demonstrated significant improvement (p < 0.04) in stress-induced ischemia in the 50-channel TMR animals, but not in the 25- or 10-channel TMR groups, as compared with scans obtained immediately before lasing. A computerized image analysis of perfusion scans similarly demonstrated an improvement in the area of ischemia of 42% +/- 22% in the scans obtained 4 weeks after lasing compared with scans obtained immediately before lasing in the 50-channel group (p < 0.004), but only a 12% +/- 9% improvement in the 25-channel group and an 8% +/- 4% improvement in the 10-channel group (p > 0.05). Histologic assessment of neovascularization demonstrated significantly greater number of microvessels per low-power field in the 50- versus the 25- and 10-channel groups (p < 0.001).

CONCLUSIONS

In an animal model of myocardial ischemia, TMR appears to enhance myocardial perfusion. A dose-response relationship related to channel number may be of significance when evaluating the efficacy of various treatment strategies.

Effects of human eosinophil granule-derived cationic proteins on C-fiber afferents in the rat lung

Experiments were performed to test the hypothesis that human eosinophil granule-derived cationic proteins stimulate vagal C-fiber afferents in the lungs and elicit pulmonary chemoreflex responses in anesthetized Sprague-Dawley rats. Intratracheal instillation of eosinophil cationic protein (ECP; 1-2 mg/ml, 0.1 ml) consistently induced an irregular breathing pattern, characterized by tachypnea (change in breathing frequency of 44.7%) and small unstable tidal volume (VT). The tachypnea, accompanied by decreased heart rate and arterial blood pressure, started within 30 s after the delivery of ECP and lasted for >30 min. These ECP-induced cardiorespiratory responses were completely prevented by perineural capsaicin treatment of both cervical vagi, which selectively blocked C-fiber conduction, suggesting the involvement of these afferents. Indeed, direct recording of single-unit activities of pulmonary C-fibers further demonstrated that the same dose of ECP evoked a pronounced and sustained (>30-min) stimulatory effect on pulmonary C-fibers. Furthermore, the sensitivity of these afferents to lung inflation was also markedly elevated after the ECP instillation, whereas the vehicle of ECP administered in the same manner had no effect. Other types of eosinophil granule cationic proteins, such as major basic protein and eosinophil peroxidase, induced very similar respiratory and cardiovascular reflex responses. In conclusion, these results show that eosinophil granule-derived cationic proteins induce a distinct stimulatory effect on vagal pulmonary C-fiber endings, which may play an important role in the airway hyperresponsiveness associated with eosinophil infiltration in the airways.

Sensitivity of vagal afferent endings to chemical irritants in the rat lung

This study was carried out to investigate the relationship between the conduction velocity of the vagal afferents arising from the rat lungs and their sensitivities to capsaicin, other chemical irritants, and lung inflation. We recorded single-unit activities of vagal pulmonary afferents (n = 205) in anesthetized, open-chest rats, and distinguished C fibers (conduction velocity < 2 m/sec) from myelinated afferents; the latter group was further classified into rapidly adapting pulmonary receptors (RARs) and slowly adapting pulmonary stretch receptors (SARs) on the basis of their adaptation indexes to lung inflation. Right-atrial injection of capsaicin (1 microg/kg) evoked an abrupt and intense stimulatory effect in 88.9% (64/72) of the pulmonary C fibers tested, but only a mild stimulation in 6.3% (3/48) of the RARs and none of the SARs. Other inhaled and injected chemical stimulants (e.g., cigarette smoke, lactic acid) activated 68.9% (42/61) of the pulmonary C fibers. The same chemical irritants exerted a mild stimulatory effect in only 14.5% (8/55) of the RARs; this subgroup of RARs exhibited a low or no baseline activity, and half of them were located near the hilum. Chemical stimulants had little or no effect on SARs. The response of pulmonary C fibers to lung inflation (tracheal pressure = 30 cm H2O) was not only extremely weak, but also showed a longer onset latency and an irregular pattern. In a sharp contrast, lung inflation evoked rapid and vigorous discharges in both RARs and SARs. In conclusion, C fibers are the primary type of chemosensitive vagal pulmonary afferents in rat lungs.

Airway reflexes, autonomic function, and cardiovascular responses

In this article, we review the cardiovascular responses to the inhalation of irritants and pollutants. Many sensory receptors in the respiratory system, from nose to alveoli, respond to these irritants and set up powerful reflex changes, including those in the cardiovascular system. Systemic hypotension or hypertension, pulmonary hypertension, bradycardia, tachycardia, and dysrhythmias have all been described previously. Most of the experiments have been acute and have been performed on anesthetized experimental animals. Experiments on humans suggest we have similar sensory systems and reflex responses. However, we must use caution when applying the animal results to humans. Most animal experiments, unlike those with humans, have been performed using general anesthesia, with irritants administered in high concentrations, and often to a restricted part of the respiratory tract. Species differences in the response to irritants are well established. We must be even more careful when applying the results of acute experiments in animals to the pathophysiologic changes observed in prolonged exposure to environmental pollution in humans.

Modulation of airway sensitivity to inhaled irritants: role of inflammatory mediators

Bronchopulmonary C-fiber endings and rapidly adapting pulmonary receptors (RARs) are primarily responsible for eliciting the defense reflexes in protecting the lungs against inhaled irritants. In anesthetized animals, inhalation of cigarette smoke, one of the common inhaled irritants, into the lungs elicits pulmonary chemoreflexes that are mediated through the stimulation of pulmonary C fibers. When the C-fiber conduction is selectively blocked in the vagus nerves, the same smoke inhalation triggered only augmented breaths, a reflex effect of activating RARs, in the same animals. Indeed, electrophysiologic study shows that inhaled smoke exerts a direct stimulatory effect on both types of afferents. Increasing evidence indicates that the excitability of these afferents and therefore their reflex actions are enhanced by airway mucosal inflammation; one such example is the airway hyperresponsiveness induced by acute exposure to ozone. Although the mechanism underlying the inflammation-induced hypersensitivity of C-fiber endings is not fully understood, the possible involvement of local release of certain inflammatory mediators, such as histamine and prostaglandin E(2) (PGE(2), should be considered. It is believed that changes in the membrane properties mediated by the activation of certain specific receptor proteins located on the membrane of these nerve terminals are involved, as the sensitizing effects of PGE(2) can be also demonstrated in cultured pulmonary C neurons.

Airway reflexes, autonomic function, and cardiovascular responses

In this article, we review the cardiovascular responses to the inhalation of irritants and pollutants. Many sensory receptors in the respiratory system, from nose to alveoli, respond to these irritants and set up powerful reflex changes, including those in the cardiovascular system. Systemic hypotension or hypertension, pulmonary hypertension, bradycardia, tachycardia, and dysrhythmias have all been described previously. Most of the experiments have been acute and have been performed on anesthetized experimental animals. Experiments on humans suggest we have similar sensory systems and reflex responses. However, we must use caution when applying the animal results to humans. Most animal experiments, unlike those with humans, have been performed using general anesthesia, with irritants administered in high concentrations, and often to a restricted part of the respiratory tract. Species differences in the response to irritants are well established. We must be even more careful when applying the results of acute experiments in animals to the pathophysiologic changes observed in prolonged exposure to environmental pollution in humans.

Novel constructions to enable the integration of genes into the Agrobacterium tumefaciens C58 chromosome

We constructed several versatile sets of vectors that can be used to introduce any gene into the pgl/picA locus of the Agrobacterium tumefaciens C58 chromosome without affecting T-DNA transfer. One set contains a fragment containing the lacIq and lacZ genes and a multiple cloning site from pBluescriptII SK(+) inserted into a PstI site between the pgl and picA genes on an incPalpha plasmid. The resulting plasmid contains eight unique restriction endonuclease sites and the ability to use blue-white screening for the presence of an insert. A second plasmid also contains a beta-lactamase gene within this locus and provides a convenient ampicillin-carbenicillin resistance marker for the selection of genes integrated into the chromosome following double homologous recombination (homogenotization). A third plasmid contains, in addition to the lacZ, lacIq, and beta-lactamase genes within the pgl/picA locus, a sacRB gene cassette within the vector to counterselect against the presence of the vector within A. tumefaciens. To test this system, we introduced a wild-type virD2 gene into the A. tumefaciens chromosome at the pgl/picA locus. When a Ti plasmid harboring a deletion of virD2 was in this strain, the integrated virD2 gene complemented the virD2 deletion and the resulting transformation phenotype was identical to that resulting from A. tumefaciens strains harboring a wild-type virD2 gene located on a replicating plasmid.

Afferent properties and reflex functions of bronchopulmonary C-fibers

Bronchopulmonary C-fiber afferents are characterized by their distinct sensitivity to chemical stimuli in the airways or pulmonary circulation. Responses evoked by activating these afferents are mediated by both central reflex pathways and by local or axon reflexes involving the release of tachykinins from sensory endings. Bronchopulmonary C-fiber stimulation reflexly reduces tidal volume and increases respiratory rate, constricts the airways, increases mucus secretion in the airways, and is associated with coughing. Cardiovascular effects include bradycardia, a fall in cardiac output, and bronchial vasodilation that increases airway blood flow despite systemic hypotension. In animals, C-fiber stimulation inhibits skeletal muscle activity, and in humans, is accompanied by burning and choking sensations in the throat and upper chest. Recent studies have identified additional physiologic and pharmacologic stimuli to these afferents, such as hydrogen ions, adenosine, reactive oxygen species, and hyperosmotic solutions. Furthermore, increasing evidence indicates that the excitability of these afferents is enhanced by the local release of certain autocoids (e.g. PGE2) during airway inflammation. These findings further indicate that vagal C-fiber endings in the lungs and airways play an important role in regulating the cardiopulmonary functions under both normal and abnormal physiologic conditions.

Digital imaging considerations for gel electrophoresis analysis systems

Gel analysis system purchasers have a large variety of digital imaging products to choose from today. Understanding the specifications presented by the manufacturers is important to ensure that the system fits the needs ofthe researcher using the system. The background information contained in this paper explains the terminology and many of the specifications along with their significance.

Percutaneous endocardial transfer and expression of genes to the myocardium utilizing fluoroscopic guidance

Experimental studies indicate that administration of angiogenic proteins or genes by the epicardial or intracoronary route can stimulate development of new collateral vessels and improve myocardial perfusion. An endocardial catheter-based approach to this therapy would obviate the need for surgery, while preserving the effectiveness of direct intramyocardial administration. Fluoroscopic guidance and prototype, preformed, coaxial catheters were used to examine the feasibility of percutaneous catheter-based adenovirus (Ad)-mediated gene transfer and expression in normal swine myocardium. The feasibility of intramyocardial administration (100 microl/injection) of a radiocontrast agent and black tissue dye to all regions of the left ventricle (septum, anterior, lateral, and inferior wall) was confirmed fluoroscopically and on postmortem examination. Injections of replication-deficient adenovirus (10 injections of 10(11) particle units/100 microl each) coding for beta-galactosidase (Adbetagal) or vascular endothelial growth factor (Ad(GV)VEGF121.10) were administered to the left ventricular free wall to examine endocardial based gene transfer and expression. beta-Galactosidase activity was detected by histochemical staining and quantitative assay in targeted regions of the myocardium. Regional VEGF expression was found to be significantly greater in targeted regions (1.3 +/- 0.4 ng/mg protein) as compared with non-targeted regions (0.3 +/- 0.1 ng/mg protein) or regions injected with control (Adbetagal) virus (0.2 +/- 0.03 ng/mg protein, P < 0.001). Catheter-based Ad mediated endocardial gene transfer and expression is feasible using percutaneous, fluoroscopically guided, preformed, coaxial catheters. This approach should be clinically useful to administer angiogenic genes to the ischemic myocardium.