Systemic Involvement in Immunoglobulin G4-Related Ophthalmic Disease

BACKGROUND

Immunoglobulin G4-related ophthalmic disease (IgG4-ROD) poses clinical challenges due to its heterogeneous ocular and systemic manifestations. We aim to report the systemic involvement and the clinical, serological and radiological associations of a cohort of Chinese patients.

METHODS

A territory-wide, biopsy-proven, Chinese cohort. A retrospective, masked chart review of medical records, orbital images, and histopathology reports.

RESULTS

A total of 122 (65 male) patients with a follow-up of 81 ± 49 (24 to 84) months were reviewed. Ninety (74%) patients presented bilaterally. Subacute upper eyelid swelling was the commonest presentation (82/122, 67%). During follow-up, 91/122 patients (75%) underwent extra-orbital imaging including computer tomography (692 films), ultrasonography (182 films), magnetic resonance imaging (76 films) and whole body FDG-PET scan (33 films). Eighty-six (95%) of these 91 patients had extra-orbital involvement radiologically (2.7 ± 1.6 regions, range: 0 to 9). Lymph node was the most prevalent (N = 60,66%), followed by salivary gland (N = 51,56%), lung (N = 49,54%), kidney (N = 22, 24%), hepatobiliary tree (N = 18, 20%) and pancreas (N = 17, 19%). Other organs include thyroid, aorta, meninges/brain and skin. Twenty-eight (23%) patients had allergic diseases (19 asthma, 16 allergic rhinitis, and 6 eczemas). Fifty-seven (48%) patients had paranasal sinusitis. Serum eosinophilia was associated with a higher number (3.24 versus 2.52, P = 0.0304) of organ involvement. Patients with deep organ involvement was associated with a higher age of IgG4-ROD onset (70 ± 12 versus 56 ± 13, P < 0.0001).

CONCLUSIONS

95% of the patients who underwent systemic imaging in our cohort had systemic organ involvement. An early physicians' assessment and radiological imaging are recommended after the diagnosis of IgG4-ROD.

Ocular Surface Evaluation in Immunoglobulin G4-Related Ophthalmic Disease

PURPOSE

To evaluate the functional and structural changes of the meibomian glands and ocular surface in immunoglobulin G4-related ophthalmic disease (IgG4-ROD) patients.

DESIGN

Cross-sectional, matched case-control comparison study.

METHODS

This study included 64 patients with biopsy-proven IgG4-ROD (aged 63.4 ± 12.2 years, 39 male) and 64 sex- and age-matched healthy controls. Patients were managed by hospitals covering the publicly funded ophthalmology service in Hong Kong. Outcome measures included anterior segment examination and keratographic and meibographic imagings.

RESULTS

A total of 64 worst-affected eyes of the 64 IgG4-ROD patients were analyzed. Corneal fluorescein staining (P = .0187), lid margin telangiectasia (P = .0360), lid-parallel conjunctival folds (P = .0112), papillae (P = .0393), meibomian gland plugging (P = .0001), meibomian gland expressibility (P = .0001), and meibum quality (P = .0001) were more significant in IgG4-ROD patients compared with healthy controls. Both upper and lower meibomian gland dropouts (P = .001 and .0003), and tear meniscus height (P = .0001) were higher in IgG4-ROD patients. Non-invasive tear break-up time (NITBUT) (P = .0166) and Schirmer test results (P = .0243) were lower in IgG4-ROD patients. Upper (r = 0.336, P = .0140) meibomian gland dropouts and NITBUT (r = -0.293, P = .0497) were positively and negatively correlated with the IgG4-ROD onset age, respectively. The number of extraocular organ involvement was negatively correlated with the Schirmer test(r = -0.341, P = .0167). Lower NITBUT was found in IgG4-ROD eyes with lacrimal gland enlargement than in IgG4-ROD eyes without lacrimal gland enlargement radiologically (P < .0001).

CONCLUSIONS

IgG4-ROD patients showed features of both aqueous tear deficiency and evaporative dry eye disease. We recommend ocular surface evaluation to all patients newly diagnosed with IgG4-ROD. Further studies are warranted to clarify the mechanism of IgG4-related dry eye disease.

Serum sphingolipids aid in diagnosing adult HIV-negative patients with pulmonary cryptococcosis: a clinical cohort study

Background

Pulmonary cryptococcosis (PC) contributes to the ongoing global disease burden in human immunodeficiency virus (HIV)-negative populations. Since some PC patients are misdiagnosed under existing diagnostic guidelines, new diagnostic markers are needed to improve diagnostic accuracy and therapeutic efficacy and reduce disease risk.

Methods

Our previously established sphingolipidomic approach was employed to explore the use of serum sphingolipids (SPLs) in diagnosing HIV-negative patients with PC. A clinical cohort of PC, pulmonary aspergillosis (PA), and tuberculosis (TB) patients and healthy controls was assessed to identify SPL biomarkers.

Results

A total of 47 PC, 27 PA, and 18 TB patients and 40 controls were enrolled. PC and TB patients had similar clinical features, laboratory test results and radiological features, excluding plural effusion. The serum ceramide [Cer (d18:1/18:0)] level showed a significant increase in PC patients compared to controls and PA and TB patients (P<0.05). Cer (d18:1/18:0) was identified as a specific diagnostic biomarker for PC. The optimal cut-off value of greater than 18.00 nM showed a diagnostic sensitivity of 76.60% and a specificity of 95.00% and better distinguished PC patients from PA and TB patients. Furthermore, the serum Cer (d18:1/18:0) level gradually decreased after 3 and 6 months of treatment, suggesting the prediction potential for therapeutic efficacy of this biomarker. In addition, Cer (d18:1/18:0) analysis presented a higher sensitivity than the cryptococcal antigen (CrAg) assay.

Conclusions

This is the first study to report the use of the SPL Cer (d18:1/18:0) as a serum biomarker for diagnosing Cryptococcus spp. infection in HIV-negative patients.

Robust quantitation of gangliosides and sulfatides in human brain using UHPLC-MRM-MS: Method development and application in Alzheimer's disease

Gangliosides (GAs) and sulfatides (STs) are acidic glycosphingolipids that are particularly abundant in the nervous system and are closely related to aging and neurodegenerative disorders. To explore their roles in brain diseases, in-depth molecular profiling, including structural variations of sphingoid backbone, fatty acyl group, and sugar chain of GAs and STs was performed. A total of 210 GAs and 38 STs were characterized in the inferior frontal gyrus (IFG) of human brain, with 90 GAs discovered in brain tissues for the first time. Influential MS parameters for detecting GAs and STs in multiple reaction monitoring (MRM) mode were systematically examined and optimized to minimize in-source fragmentation, resulting in remarkable signal intensity enhancement for GAs and STs, especially for polysialylated species. To eliminate analytical variations, isotopic interference-free internal standards were prepared by simple and fast reduction reaction. The final established method facilitated the simultaneous quantitation of 184 GAs and 30 STs from 25 subtypes, which represents the highest number of GAs quantitated among all quantitation methods recorded in literature so far. The method was further validated and applied to reveal the aberrant change of GAs and STs in the IFG of 12 Alzheimer's disease (AD) patients. Four GAs exhibited high classification capacity for AD (AUC ≥0.80) and were thereby considered the most promising signatures for AD. These findings suggested the close correlation between GAs and the pathogenesis of AD, highlighting the achievements of our robust method for investigating the roles of GAs and STs in various physiological states and diseases.

Malignancies in Immunoglobulin G4-related ophthalmic disease

PURPOSE

Clinical phenotypes in Immunoglobulin G4-related disease (IgG4-RD) according to the patterns of affecting organs have different risks of malignancies. We attempt to determine the association of malignancies with IgG4-related ophthalmic disease (IgG4-ROD).

DESIGN

Retrospective cohort study.

METHODS

Review of medical records, orbital images and histopathology reports in a territory-wide cohort of biopsy proven IgG4-ROD patients from 2005-2019.

FINDINGS

Among 122 patients who had biopsies taken from adnexal lesions including lacrimal glands (n = 108), orbital mass (n = 30), infiltrated orbital fat (n = 10), conjunctiva (n = 2) or extraocular muscles (n = 3), 13% (16/122) developed malignancies over 73 ± 48months' follow-up. There were 9 cases of ocular adnexal lymphoma (OAL) and 7 extra-orbital malignancies. Compared with the general population, the incidence of OAL was significantly higher (standardized incidence ratios, SIRs = 10.0, 95%CI = 4.5-17.6) while that of extra-orbital malignancies was similar. The SIRs was highest within the first year (SIR = 46.7, 95%CI = 18.5-87.6) when 7 OAL were concomitantly diagnosed. Patients who developed OAL or extra-orbital malignancies were older than other patients at IgG4-ROD diagnosis (64.9 ± 7.1, 68.3 ± 8.5 versus 55.2 ± 15.0 years, P < 0.05). Asymmetric lacrimal gland enlargement (78% versus 13%), lack of frontal (0% versus 12%) or infraorbital nerve enlargement (0% versus 36%) were associated with OAL (all P < 0.05). Pre-treatment serum IgG4 level or extra-orbital IgG4-RD involvement was similar among patients with or without malignancies.

CONCLUSION

In this biopsy-proven IgG4-ROD cohort, 7% developed OAL which was 10 times higher than the general population. Patients with asymmetric lacrimal gland enlargement or without trigeminal nerves involvement radiologically were associated with OAL.

Improvement of tissue-specific distribution and biotransformation potential of nicotinamide mononucleotide in combination with ginsenosides or resveratrol

Decreased Nicotinamide adenine dinucleotide (NAD⁺) level has received increasing attention in recent years since it plays a critical role in many diseases and aging. Although some research has proved that supplementing nicotinamide mononucleotide (NMN) could improve the level of NAD⁺, it is still uncertain whether the NAD⁺ level in specific tissues could be improved in combination with other nutrients. So far, a variety of nutritional supplements have flooded the market, which contains the compositions of NMN coupled with natural products. However, the synergy and transformation process of NMN has not been fully elucidated. In this study, oral administration of NMN (500 mg/kg) combined with resveratrol (50 mg/kg) or ginsenoside Rh2&Rg3 (50 mg/kg) was used to validate the efficacy of appropriate drug combinations in mice. Compared with NMN alone, NMN combined with resveratrol could increase the levels of NAD⁺ in the heart and muscle by about 1.6 times and 1.7 times, respectively, whereas NMN coupled with ginsenoside Rh2&Rg3 could effectively improve the level of NAD⁺ in lung tissue for approximately 2.0 times. Our study may provide new treatment ideas for aging or diseases in cardiopulmonary caused by decreased NAD⁺ levels.

Serum Sphingolipids Aiding the Diagnosis of Adult HIV-Negative Patients with Talaromyces marneffei Infection

Increasing attention has been directed to Talaromyces marneffei (T. marneffei) infection in HIV-negative patients due to its high mortality rate. However, nonspecific symptoms and biological characteristics similar to those of other common pathogenic fungi complicate the rapid and accurate diagnosis of T. marneffei infection. Sphingolipids (SPLs) are bioactive lipids involved in the regulation of various physiological and pathological processes and have been identified as serum biomarkers for several diseases. This study employed a sphingolipidomic approach established in our previous work to explore the use of serum SPLs in the diagnosis of HIV-negative patients with T. marneffei infection. Additional clinical cohorts of patients infected with other microorganisms were also recruited. We found that sphinganine (Sa) (d16:0) exhibited obvious depletion after infection; moreover, its level in patients with T. marneffei infection was significantly lower than that in patients infected with other microorganisms. Therefore, Sa (d16:0) was considered a specific diagnostic biomarker for T. marneffei infection, and 302.71 nM was selected as the optimal cutoff value with a diagnostic sensitivity of 87.5% and specificity of 100%. These results suggested that determination of serum Sa (d16:0) levels can be used as a new alternative tool for the rapid diagnosis of T. marneffei infection in HIV-negative patients.

From proliferation to target innervation: signaling molecules that direct sympathetic nervous system development

The sympathetic division of the autonomic nervous system includes a variety of cells including neurons, endocrine cells and glial cells. A recent study (Furlan et al. 2017) has revised thinking about the developmental origin of these cells. It now appears that sympathetic neurons and chromaffin cells of the adrenal medulla do not have an immediate common ancestor in the form a "sympathoadrenal cell", as has been long believed. Instead, chromaffin cells arise from Schwann cell precursors. This review integrates the new findings with the expanding body of knowledge on the signalling pathways and transcription factors that regulate the origin of cells of the sympathetic division of the autonomic nervous system.

Promoting Smoking Cessation Among the Elderly

Purpose: To assess the predictors of smoking cessation and intention to quit among the Chinese elderly smokers. Design: A cross-sectional survey of elderly smokers. Setting: Shamsuipo district, Hong Kong. Subject: A total of 1,318 elderly were interviewed (response rate = 83%). Measures: A structured questionnaire was used for data collection. The questionnaire sought information on the subject's sociodemographic background and smoking habits. The predictors for successful quitting and intention to quit were assessed by chi-square tests and multiple logistic regression. Results: Of the respondents, 20.2% were current smokers, 25.4% were ex-smokers, and 54.4% were never smokers. Of the smoker (current and ex-smokers) respondents, 55.7% (335/601) had successfully quit at the time of enumeration. The predictors of quitting were living with others, receiving assistance for mobility, being nondrinkers, smoking for shorter duration, and smoking more cigarettes per day. Having health problems in the past, smoking for shorter duration, and smoking fewer cigarettes per day were predictors of intention to quit smoking. Conclusion:The study identified several predictors of successful quitting that could help improve the provision of current smoking cessation services. Population-based smoking cessation programs, especially those targeted to elderly, should take these predictors into consideration in the design of interventions.

MicroRNA-21 promotes proliferation of rat hepatocyte BRL-3A by targeting FASLG

Rat liver regeneration (RLR) induced by partial hepatectomy involves cell proliferation regulated by numerous factors, including microRNAs (miRNAs). miRNA high-throughput sequencing has been established and used to analyze miRNA expression profiles. This study showed that 39 miRNAs were related to RLR through the analysis of miRNA high-throughput sequencing. Their role toward rat normal hepatocyte line BRL-3A was studied by gain- and loss-of-function analyses, and one of them, microRNA-21 (miR-21), obviously upregulated and promoted BRL-3A cell proliferation. Using bioinformatics to search for miR-21 targets revealed that Fas ligand (FASLG) is one of miR-21's target genes. A dual-luciferase report assay and Western blot assay showed that miR-21 directly targeted the 3'-untranslated region of FASLG and inhibited the expression of FASLG, which suggests that miR-21 promoted BRL-3A cell proliferation by reducing FASLG expression.

Facile synthesis and characterization of highly fluorescent and biocompatible N-acetyl-L-cysteine capped CdTe/CdS/ZnS core/shell/shell quantum dots in aqueous phase

The synthesis of water-soluble quantum dots (QDs) in aqueous phase has received much attention recently. To date various kinds of QDs such as CdTe, CdSe, CdTe/CdS and CdSe/ZnS have been synthesized by aqueous methods. However, generally poor-quality QDs (photoluminescent quantum yield (PLQY) lower than 30%) are obtained via this method and the 3-mercaptopropionic acid stabilizer is notorious for its toxicity and awful odor. Here we introduce a novel thiol ligand, N-acetyl-L-cysteine, as an ideal stabilizer that is successfully employed to synthesize high-quality CdTe/CdS/ZnS QDs via a simple aqueous phase. The core/shell/shell structures of the CdTe/CdS/ZnS QDs were verified by x-ray photoelectron spectroscopy, energy dispersive x-ray spectroscopy, x-ray powder diffraction and transmission electron microscopy. These QDs not only possess a high PLQY but also have excellent photostability and favorable biocompatibility, which is vital for many biological applications. This type of water-dispersed QD is a promising candidate for fluorescent probes in biological and medical fields.

Randomized controlled trial of standard versus high-dose intravenous omeprazole after endoscopic therapy in high-risk patients with acute peptic ulcer bleeding

Background

Rebleeding from peptic ulcers is a major contributor to death. This study compared standard (40-mg intravenous infusion of omeprazole once daily for 3 days) and high-dose (80-mg bolus of omeprazole followed by 8-mg/h infusion for 72 h) in reducing the rebleeding rate (primary endpoint), need for surgery, duration of hospital stay and mortality in patients with peptic ulcer bleeding after successful endoscopic therapy.

Methods

This was a single-institution prospective randomized controlled study based on a postulated therapeutic equivalence of the two treatments. All patients who had successful endoscopic haemostasis of a bleeding peptic ulcer (Forrest classification Ia, Ib, IIa or IIb) were recruited. Informed consent was obtained and patients were randomized to receive standard- or high-dose infusions of intravenous omeprazole.

Results

Two (3 per cent) of 61 patients in the high-dose group and ten (16 per cent) of 61 in the standard-dose group exhibited rebleeding, a difference of − 13 (95 per cent confidence interval − 25 to − 2) per cent. The upper limit of the one-sided confidence interval exceeded a predefined equivalence absolute difference of 16 per cent. Equivalence of standard- and high-dose omeprazole in preventing rebleeding was not demonstrated.

Conclusion

Intravenous standard-dose omeprazole was inferior to high-dose omeprazole in preventing rebleeding after endoscopic haemostasis for peptic ulcer bleeding. Registration number: NCT00519519 (http://www.clinicaltrials.gov).

Quantum dot-ruthenium complex dyads: recognition of double-strand DNA through dual-color fluorescence detection

We have developed a new fluorescent ensemble probe comprising an ionic conjugate between water-soluble thioglycolic acid (TGA) capped CdTe quantum dots (QDs) and Ru(bpy)(2)(dppx)(2+) for the dual-color detection of complementary double-stranded DNAs (dsDNA). To provide the platform for DNA detection, the Ru-complex was first employed as an effective fluorescence quencher to TGA capped QDs via photoinduced electron transfer process. Because of its strong binding affinity with Ru(bpy)(2)(dppx)(2+), complementary dsDNA can break up the low fluoresced ionic ensemble, set free the luminescent QDs, and concomitantly generate the Ru(bpy)(2)(dppx)(2+) intercalated DNA complex. Thus, the recognition of dsDNA by Ru(bpy)(2)(dppx)(2+) can be realized via both the restoration of QDs fluorescence and the emergence of a new fluorescence emission signal of the quencher-substrate at 609 nm, while single-stranded DNA, ribonucleic acid, bovine albumin serum, and biological relevant metal ions cannot produce the similar results. Therefore, a simple, fast, sensitive, and highly selective assay for dsDNA has been realized.

Improvement of conversion efficiency for multi-junction solar cells by incorporation of Au nanoclusters

We studied the photoluminescence (PL) and photovoltaic current-voltage characteristics of the three-junction InGaP/InGaAs/Ge solar cells by depositing Au nanoclusters on the cell surface. The increases of the PL intensity and short-circuit current after incorporation of Au nanoclusters are evident. An increase of 15.3% in energy conversion efficiency (from 19.6 to 22.6%) is obtained for the three-junction solar cells in which Au nanoclusters have been incorporated. We suggest that the increased light trapping due to radiative scattering from Au nanoclusters is responsible for improving the performance of the three-junction solar cells.

Unique hepatic imaging features in a patient with nodular regenerative hyperplasia of the liver associating with systemic lupus erythematosus

Nodular regenerative hyperplasia (NRH) of the liver, characterized by regenerative nodules distributed throughout the liver in the absence of fibrosis, is a rare but important complication of systemic lupus erythematosus (SLE). The main consequence of NRH is non-cirrhotic portal hypertension. We describe a female patient who had immune thrombocytopenia in association with elevated liver enzymes and evidence of portal hypertension as initial manifestations of SLE. Computed tomographic scan and magnetic resonance imaging of the liver in this patient showed enhancing periportal tubular structures distributed throughout the liver. The diagnosis of NRH was eventually disclosed by transcutaneous needle liver biopsy. The pattern of radiological abnormality in this patient has not been described previously in NRH. In addition, we believe this is a first reported case of SLE presenting with immune thrombocytopenia in association with NRH.

Incidence of neonatal chlamydial conjunctivitis and its association with nasopharyngeal colonisation in a Hong Kong hospital, assessed by polymerase chain reaction

OBJECTIVES

Using polymerase chain reactions, this study aimed to evaluate the incidence of neonatal chlamydial conjunctivitis in our region of Hong Kong and explore any association between such conjunctivitis and nasopharyngeal colonisation with Chlamydia trachomatis.

DESIGN

Prospective epidemiological study.

SETTING

Regional hospital, Hong Kong.

PATIENTS

Consecutive patients with neonatal conjunctivitis presenting to our hospital were recruited from May 2004 to April 2005 inclusive. Both eyes were investigated separately for Chlamydia trachomatis by polymerase chain reaction, direct immunofluorescent assay, and cell culture by two assigned ophthalmologists. Neonates diagnosed to have ocular Chlamydia trachomatis infection were subjected to additional nasopharyngeal investigations. Complete sets of ocular and nasopharyngeal investigations were also undertaken 1 week after oral erythromycin treatment to confirm complete eradication of Chlamydia trachomatis.

RESULTS

Of 192 patients with neonatal conjunctivitis, 24 were diagnosed to have chlamydial conjunctivitis. Fifteen of them had nasopharyngeal colonisation with Chlamydia trachomatis. Among the 20 neonatal chlamydial conjunctivitis patients that completed the follow-up study, one suffered treatment failure. None had clinically diagnosed systemic Chlamydia trachomatis infection 3 months after oral erythromycin.

CONCLUSIONS

The incidence of neonatal chlamydial conjunctivitis in our region of Hong Kong was 4 in 1000 live births, of whom 63% had nasopharyngeal presence of Chlamydia trachomatis. Owing to the high rate of nasopharyngeal isolation and possibility of treatment failure, post-treatment ocular and nasopharyngeal polymerase chain reaction testing for Chlamydia trachomatis may be considered to confirm complete eradication.

Oesophageal tuberculosis mimicking oesophageal carcinoma

Tuberculous involvement of the oesophagus is rare, and is usually caused by direct spread from adjacent afflicted structures. We report an 83-year-old male patient with oesophageal tuberculosis secondary to tuberculous mediastinal lymphadenitis who presented with non-specific symptoms of anorexia and lethargy. Upper gastro-intestinal endoscopy revealed an ulcerative tumour-like lesion in the mid-oesophagus suggesting oesophageal carcinoma. Repeated endoscopic biopsies revealed a non-specific acute-on-chronic inflammation consisting of non-caseating granulomas, with no evidence of malignancy. Endoscopic ultrasonography demonstrated that the oesophageal lesion was secondary to direct extension of mediastinal lymphadenopathy. The diagnosis of tuberculosis was eventually confirmed by histological and microbiological analysis of a surgically excised cervical lymph node. The patient responded promptly to treatment with antituberculous drugs. We suggest that oesophageal tuberculosis has to be kept in mind in the differential diagnosis of oesophageal ulcerohypertrophic lesions.

Clinical validation of a link between TNF-alpha and the glycosylation enzyme core 2 GlcNAc-T and the relationship of this link to diabetic retinopathy

AIMS/HYPOTHESIS

Increasing evidence suggests that chronic, subclinical inflammation plays an important role in the pathogenesis of diabetic retinopathy. We recently reported that a glycosylating enzyme, core 2 beta-1,6-N-acetylglucosaminyltransferase (core 2 GlcNAc-T), is implicated in increased leucocyte-endothelial cell adhesion in diabetic retinopathy via an upregulation mechanism controlled by TNF-alpha.

SUBJECTS, MATERIALS AND METHODS

We examined the functional link between circulating TNF-alpha and the activity and phosphorylation of core 2 GlcNAc-T in polymorphonuclear leucocytes of patients with type 1 and type 2 diabetes.

RESULTS

Plasma levels of TNF-alpha, although similar in patients with type 1 and type 2 diabetes, were significantly higher than in age-matched healthy controls, and correlated well with the severity of retinopathy. Core 2 GlcNAc-T activity followed the same trend and was associated with phosphorylation of the enzyme. Finally, the observation that TNF-alpha levels are also linked to glycaemic values suggests that in patients, as well as in vitro, the glycosylation-mediated cell adhesion process that plays a role in diabetic retinopathy may involve glucose- and TNF-alpha-induced protein kinase beta2 activation, and subsequently raise activity of core 2 GlcNAc-T through increased enzyme phosphorylation.

CONCLUSIONS/INTERPRETATION

Our results reveal a novel rationale towards a specific treatment of diabetic retinopathy, based on the inhibition of core 2 GlcNAc-T activity and/or the blockage of cognate glycans.

Intestinal tuberculosis in a regional hospital in Hong Kong: a 10-year experience

OBJECTIVE

To study the clinical and pathological characteristics of patients with intestinal tuberculosis.

DESIGN

Retrospective study.

SETTING

United Christian Hospital, Hong Kong.

PATIENTS

Patients with intestinal tuberculosis diagnosed between January 1995 and December 2004 inclusive.

RESULTS

The median age of the 13 male and 9 female patients was 53 years (range, 12-81 years). Nineteen (86%) had a definitive diagnosis of intestinal tuberculosis confirmed by the presence of caseating granulomas and/or acid-fast bacilli in histological specimens. In three (14%) the diagnosis was based on histology revealing non-caseating granulomas and a positive response to anti-tuberculous treatment. Common symptoms included abdominal pain (82%), diarrhoea (55%), weight loss (55%), and fever (45%). Three (14%) of the patients were complicated by intestinal obstruction, and another two (9%) had intestinal perforation. Four (18%) had concomitant active pulmonary tuberculosis. The most frequently involved site was the ileocaecal region, which was affected in 19 (86%) patients. Other sites included the jejunum, ascending and sigmoid colon. The diagnosis of intestinal tuberculosis was facilitated by examination of colonoscopic biopsy specimens (11 patients), and by examination of resected surgical specimens in the remainder. Two patients died from terminal malignancy. The remainder completed anti-tuberculous therapy and responded satisfactorily.

CONCLUSIONS

The diagnosis of intestinal tuberculosis is difficult due to the lack of specific signs or symptoms. Colonoscopy with ileoscopy are useful tools in the search for colonic and terminal ileal tuberculosis. Surgical exploration is reserved for equivocal cases and for those who present as emergencies.

Alteration of foot temperature in diabetic neuropathy: is it another piece of puzzle?

Poor glycaemic control and the duration of diabetes mellitus are known to accelerate development and progression of neuropathy. Diabetic co-morbidities: hypertension and hyperlipidaemia, have been postulated to associate with development of neuropathy. A diabetic foot with low temperature and frequent exposure to low temperature environment has recently been hypothesized to be at higher risk to develop early neuropathy. This cross-sectional study is undertaken to identify risk factors for diabetic neuropathy and the association between foot temperature and development of diabetic neuropathy by using simple clinical examination in the outpatient setting. From April 18, to April 30, 2005, universal sampling method was used to select 134 diabetic patients (type 1 or type 2 for >1 year) with peripheral neuropathy. Excluded are those with chronic alcoholism, drug-induced neuropathy, dietary history of vitamin B deficiency and family history of porphyria and hereditary sensorimotor neuropathy. The patient's duration of diabetes, glycaemic control status and the presence of co-morbids: hypertension and hyperlipidemia, were recorded. The temperature of the foot was measured by using thermo buddy. Of 134 patients representing Malaysian ethnic distribution with an equal number of males and females, 20.1% were in the age group of 61 to 65 years and, 85.1% and 67.9% belonged to lower socioeconomic and educational groups respectively. Associations between diabetic neuropathy and glycaemic control (p = 0.018) and duration of diabetes (p < 0.05) were significant. However, hypertension, hyperlipidaemia and low foot temperature were not significantly associated with development of diabetic neuropathy. Poor glycaemic control is significantly associated with diabetic neuropathy. Foot temperature alteration is merely an effect of autonomic neuropathy with a cold foot is attributed to co-existing peripheral arterial disease.

Synthesis of Enantiopure Sulfinimines (Thiooxime S-Oxides) Catalyzed by Yb(OTf)3 from p-Toluenesulfinamide and Aldehydes in Mild Reaction Conditions

Enantiomerically pure sulfinimines as important building blocks in the asymmetric synthesis of amine derivatives are prepared in good to excellent yields from chiral p-toluenesulfinamide with aromatic, heteroaromatic, and aliphatic aldehydes. The unprecedented feature of the reported procedure is that the formation of the sulfinimines was achieved by the catalytic action of Yb(OTf)(3) in THF at room temperature. The reaction conditions were also applicable to Ellman's sulfinimines.

Movement compatibility for rotary control and circular display--Computer Simulated Test and real Hardware Test

This experiment studied strength and reversibility of direction-of-motion stereotypes and response times for different configurations of circular displays and rotary knobs. The effect of pointer position, instruction of turn direction, and control plane on movement compatibility was analyzed with precise quantitative measures of strength and reversibility index of stereotype. A comparison of results was made between a Computer Simulated Test and a Hardware Test with real rotary controls. There was consensus in the results of the two tests that strong and significantly reversible clockwise-for-clockwise (CC) and anticlockwise-for-anticlockwise (AA) stereotypes were obtained at the 12 o'clock position. Subjects' response times were found to be generally longer when there were no clear movement stereotypes. Nevertheless, differences of results were observed that while the CC and AA preferences were found to be dominant and reversible at all the planes and pointer positions in the Hardware Test, there was variation in the strength and reversibility of the two stereotypes amongst different testing configurations in the Simulated Test. This phenomenon was explained by the operating of the clockwise-for-right and anticlockwise-for-left principles, as shown in the analysis of contributions of component principles to the overall stereotype. The differences of results from the two tests were discussed with regard to simulation fidelity and it was suggested that a real Hardware Test should be used whenever possible for determination of design parameters of control panels in consideration of movement compatibility. Based on the Hardware Test, a pointer is recommended to be positioned at 12 o'clock position for check reading or resetting purpose, and the frontal plane is the best plane for positioning a rotary control with circular display. The results of this study provided significant implications for the industrial design of control panels used in man-machine interfaces for improved human performance.

An elasto-plastic finite element model for polyethylene wear in total hip arthroplasty

A new finite element model (FEM) based on an elasto-plastic behavior of ultra high molecular weight polyethylene (UHMWPE) was used to study the wear behavior of UHMWPE acetabular cup, which has a 32 mm diameter femoral head. The model imposed a plastic yield stress of 8 MPa on the UHMWPE so that any stresses beyond this would automatically be redistributed to its neighbor. The FEM model adopted a unique mesh design based on an open cube concept which eliminated the problems of singularities. Wear prediction combined the influences of contact stress, sliding distance and a surface wear coefficient. The new model predicted significantly higher volumetric wear rate (57 mm(3)/yr) well within the average reported clinical values. The model was also used to study the effect of friction and clearance between the acetabular cup and the femoral head. Increase in friction increased the volumetric wear rate but did not appear to affect the linear wear rate, which remained at 0.12 +/- 0.02 mm/yr. The predicted wear was sensitive to clearance. It was found that when the clearance was close to 0 and >0.5mm, severe wear occurred. The best clearance range was between 0.1 and 0.15 mm where the average linear wear rate was 0.1mm/yr and the volumetric wear was 55 mm(3)/yr. The present work indicates the importance of avoiding too tight or too loose a diametrical clearance.

Determination of airborne formaldehyde by active sampling on 3-methyl-2-benzothiazolinone hydrazone hydrochloride-coated glass fibre filters

Formaldehyde was sampled with the use of a standard miniature glass fibre filter coated with 3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH). The formaldehyde hydrazone formed [i.e., the adduct of formaldehyde (HCHO) and MBTH] was desorbed from the filter with water and then oxidised by an iron(III) chloride-sulfamic acid solution to form a blue cationic dye in acidic medium which was subsequently determined by visible absorption at 628 nm. The recovery of HCHO as the cationic dye from MBTH-coated filters is 87-102% in the range 0.065-2.9 micrograms of HCHO. This corresponds to 4.3-193.3 micrograms m-3 in a 15 L air sample. The collection efficiency of the MBTH-coated filter is higher than 90%. When the filter sampling system is used in active mode, air can be sampled at a rate of up to 1 L min-1, affording an overall sensitivity of about 3 micrograms m-3, corresponding to about 2 ppb v/v HCHO at 1 atm and 273 K. The method was successfully applied to the determination of HCHO in samples of indoor and outdoor air with satisfactory results.

Enzyme-linked immunosorbent assay for the determination of p21-activated kinase activity

An enzyme-linked immunosorbent assay (ELISA) for the measurement of p21-activated kinase (PAK) activity is described. The development of this method takes advantage of the fact that a phospho-epitope-specific antibody against the regulatory autophosphorylation site sequence of PAK was successfully produced, and after being phosphorylated by PAK, a cross-linked peptide containing the autophosphorylation site of PAK could be recognized on immunoblot by this antibody. This procedure involves coating the cross-linked peptide on microtiter plates, phosphorylating the cross-linked peptide by adding active PAK plus ATP.Mg(2+), and detecting peptide phosphorylation using the phospho-epitope-specific antibody and secondary antibody conjugated with alkaline phosphatase followed by reaction with p-nitrophenyl phosphate (for colorimetric detection) or fluorescein diphosphate (for fluorimetric detection). The PAK activity detected by this method was linearly proportional to the amount of kinase used in the reaction and to the duration of the kinase reaction. Furthermore, fluorimetric detection proved more sensitive than colorimetric detection in terms of both detection limit and signal magnitude. Kinase inhibitor assay revealed that the IC(50) value of staurosporine obtained by this ELISA was very close to that obtained in radioassay. Besides staurosporine, the inhibitory activity of several kinase inhibitors was also tested by the PAK ELISA. The results taken together demonstrate the feasibility and efficacy of this solid phase method for the measurement of PAK activity in a non-radioactive way. Development of this method can be helpful in further high-throughput screening of potential inhibitors of this kinase.

Significance of a positive oesophageal margin in stomach cancer

BACKGROUND

A positive oesophageal margin is frequently encountered in total and proximal gastrectomies. It is controversial as to whether a positive oesophageal margin in gastrectomy predisposes to anastomotic dehiscence and loco-regional recurrence. Its independent impact on survival has not been fully addressed.

METHODS

A retrospective review of 137 total and proximal gastrectomies for adenocarcinoma was undertaken. Independent prognostic factors were identified in a bivariate and Cox proportional hazards regression model.

RESULTS

The prevalence of positive oesophageal margin was 18.2%. A positive oesophageal margin was not associated with increased anastomotic leak (8.0 vs 10.7%; P = 0.51), operative morbidity (32.0 vs 27.7%; P = 0.85) or 30-day mortality (8.0 vs 5.4%; P = 0.48) rates when compared with a negative margin. In addition, it did not predispose to anastomotic (13.0 vs 10.4%; P = 0.47) or regional (22.7 vs 24.5%; P = 0.51) recurrences. In the multivariate analysis the TNM stage and status of the oesophageal margin were the only independent prognostic factors for survival.

CONCLUSIONS

A positive oesophageal margin is an independent poor prognostic factor for long-term survival in stomach cancer. All efforts should therefore be made to clear the oesophageal margin in total and proximal gastrectomies.

Apoptotic signalling cascade in photosensitized human epidermal carcinoma A431 cells: involvement of singlet oxygen, c-Jun N-terminal kinase, caspase-3 and p21-activated kinase 2

Photodynamic treatment (PDT) elicits diverse cellular responses and can also cause apoptosis. In the present study the cascade of signalling events involved in PDT-induced apoptosis was investigated using Rose Bengal (RB) as the photosensitizer, and human epidermal carcinoma A431 cells as the cell model. We show that a 36-kDa kinase detected by an in-gel kinase assay is markedly activated during PDT-triggered apoptosis. Immunoblot analysis revealed that this 36-kDa kinase represents the C-terminal catalytic fragment of p21-activated kinase (PAK)2. Generation of this active fragment of PAK2 is mediated by the caspase family of proteases, which are activated by PDT. The specific caspase inhibitors (acetyl-Asp-Glu-Val-Asp-aldehyde and acetyl-Tyr-Val-Ala-Asp-chloromethylketone) block the PDT-induced caspase-3 activation and subsequent PAK2 cleavage/activation, indicating a major role for the caspase family proteases in PDT-induced apoptosis. Both PDT-induced caspase-3 activation and PAK2 cleavage/activation can be inhibited by the singlet oxygen scavengers, L-histidine and alpha-tocopherol, but not the hydroxyl radical scavenger, mannitol, demonstrating that singlet oxygen is an immediate early-apoptotic signal generated by PDT. In addition, PDT can induce a two-stage activation of the c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) in A431 cells; the early-stage JNK activation is singlet oxygen-dependent, whereas the late-stage JNK activation is mediated by the singlet oxygen-triggered caspase activation. Experiments using anti-sense oligonucleotides against JNK1 and PAK2 further show that during PDT-induced apoptosis the early-stage JNK activation is required for caspase activation, and that the late-stage JNK activation is regulated by the caspase-mediated cleavage/activation of PAK2. Collectively, a model for the PDT-triggered apoptotic signalling cascade with RB is proposed, which involves singlet oxygen, JNK, caspase-3 and PAK2, sequentially.

Inhibition of UV irradiation-induced oxidative stress and apoptotic biochemical changes in human epidermal carcinoma A431 cells by genistein

Ultraviolet (UV) light is a strong apoptotic trigger that can induce a caspase-dependent biochemical change in cells. We previously showed that UV irradiation can elicit caspase-3 activation and the subsequent cleavage and activation of p21-activated kinase 2 (PAK2) in human epidermal carcinoma A431 cells. We report that genistein, an isoflavone compound with known inhibitory activities to protein tyrosine kinases (PTKs) and topoisomerase-II (topo-II), can prevent UV irradiation-induced apoptotic biochemical changes (DNA fragmentation, caspase-3 activation, and cleavage/activation of PAK2) in A431 cells. Surprisingly, two typical PTK inhibitors (tyrphostin A47 and herbimycin A) and three known topo-II inhibitors (etoposide, daunorubicin, and novomycin) had no effect on UV irradiation-induced apoptotic biochemical changes, suggesting that the inhibitory effect of genistein is not dependent on its property as a PTK/topo-II inhibitor. In contrast, azide, a reactive oxygen species (ROS) scavenger, could effectively block the UV irradiation-induced apoptotic cell responses. Flow cytometric analysis using the cell-permeable dye 2',7'-dichlorofluorescin diacetate as an indicator of the generation of ROS showed that UV irradiation caused increase of the intracellular oxidative stress and that this increase could be abolished by azide, suggesting that oxidative stress plays an important role in mediating the apoptotic effect of UV irradiation. Importantly, the UV irradiation-induced oxidative stress in cells could be significantly attenuated by genistein, suggesting that impairment of ROS formation during UV irradiation is responsible for the antiapoptotic effect of genistein. Collectively, our results demonstrate the involvement of oxidative stress in the UV irradiation-induced caspase activation and the subsequent apoptotic biochemical changes and show that genistein is a potent inhibitor for this process.

Prophylactic intravenous ondansetron reduces the incidence of intrathecal morphine-induced pruritus in patients undergoing cesarean delivery

Pruritus is a common side effect of intrathecal morphine injection for postoperative pain control. Its incidence is especially high in patients undergoing cesarean delivery. We investigated the effectiveness of ondansetron in preventing intrathecal morphine-induced pruritus in such patients. We included 60 consecutive nonbreastfeeding women who were scheduled for elective cesarean delivery. After the administration of spinal anesthesia with bupivacaine and intrathecal morphine 0.15 mg injection, the patients were randomly divided into three groups. Group 1 received placebo (normal saline) IV injection, Group 2 diphenhydramine 30 mg IV injection, and Group 3 ondansetron 0.1 mg/kg IV injection. The incidence of pruritus was significantly lower in the ondansetron group (25%) when compared with that in the placebo group (85%) and in the diphenhydramine group (80%) (both P < 0.05). The postoperative pain score and time to flatus passage were not significantly different among the three groups. There were no headache or extrapyramidal signs associated with ondansetron use. In conclusion, ondansetron prophylaxis significantly reduced the incidence of intrathecal morphine-induced pruritus in patients undergoing cesarean delivery.

IMPLICATIONS

Ondansetron prophylaxis significantly decreases the incidence of pruritus, a common side effect of intrathecal morphine used to treat postcesarean delivery pain.

Inhibition of UV irradiation-induced oxidative stress and apoptotic biochemical changes in human epidermal carcinoma A431 cells by genistein

Ultraviolet (UV) light is a strong apoptotic trigger that can induce a caspase-dependent biochemical change in cells. We previously showed that UV irradiation can elicit caspase-3 activation and the subsequent cleavage and activation of p21-activated kinase 2 (PAK2) in human epidermal carcinoma A431 cells. We report that genistein, an isoflavone compound with known inhibitory activities to protein tyrosine kinases (PTKs) and topoisomerase-II (topo-II), can prevent UV irradiation-induced apoptotic biochemical changes (DNA fragmentation, caspase-3 activation, and cleavage/activation of PAK2) in A431 cells. Surprisingly, two typical PTK inhibitors (tyrphostin A47 and herbimycin A) and three known topo-II inhibitors (etoposide, daunorubicin, and novomycin) had no effect on UV irradiation-induced apoptotic biochemical changes, suggesting that the inhibitory effect of genistein is not dependent on its property as a PTK/topo-II inhibitor. In contrast, azide, a reactive oxygen species (ROS) scavenger, could effectively block the UV irradiation-induced apoptotic cell responses. Flow cytometric analysis using the cell-permeable dye 2',7'-dichlorofluorescin diacetate as an indicator of the generation of ROS showed that UV irradiation caused increase of the intracellular oxidative stress and that this increase could be abolished by azide, suggesting that oxidative stress plays an important role in mediating the apoptotic effect of UV irradiation. Importantly, the UV irradiation-induced oxidative stress in cells could be significantly attenuated by genistein, suggesting that impairment of ROS formation during UV irradiation is responsible for the antiapoptotic effect of genistein. Collectively, our results demonstrate the involvement of oxidative stress in the UV irradiation-induced caspase activation and the subsequent apoptotic biochemical changes and show that genistein is a potent inhibitor for this process.

Adverse operative risk factors for perforated peptic ulcer

INTRODUCTION

Mortality from perforated peptic ulcer still remains high as a result of more perforations in the elderly who are generally more ill. We conducted this retrospective study to determine the adverse operative risk factors for perforated peptic ulcers.

MATERIALS AND METHODS

Two hundred and six consecutive patients operated for perforated peptic ulcers from 1 January 1993 to 31 December 1997 were reviewed.

RESULTS

Majority (n = 194) of the patients had perforations at the pyloroduodenal region and the remaining 10 patients had perforated benign gastric ulcers. The median age at surgery was 58 years (range 18 to 91 years). Forty-four patients (21.4%) were more than 70 years old. The 30-day operative mortality rate was 10.7% (n = 22). Advanced age (> 70 years), female gender, concurrent major medical illness, perforation developed while hospitalised for other medical illnesses, prolonged perforation (> 24 hours) and preoperative hypotension (systolic blood pressure < 90 mmHg) were indicators for operative mortality by univariate analysis. By logistic regression analysis, only concurrent major medical illness, prolonged perforation and preoperative hypotension were independent adverse risk factors. The operative mortality rate for patients with 0, 1, 2 and 3 independent adverse risk factors were 0%, 11%, 30% and 88%, respectively.

CONCLUSIONS

As concurrent medical illness is a non-modifiable factor and preoperative hypotension is usually resulting from treatment delay and inadequate resuscitation, emphasis should place on shortening the time to surgery as well as prompt resuscitation.

Results of surgical resection of oesophageal carcinoma in Singapore

INTRODUCTION

The 5-year survival rate after resection of oesophageal cancer is still poor, reported to be between 5% to 34% in the literatures. We conducted this retrospective study to determine the prognostic factors and long-term survival rate for surgical resection of oesophageal carcinoma in Singapore.

MATERIALS AND METHODS

Sixty-seven consecutive patients who underwent surgical resection of oesophageal carcinoma from January 1989 to December 1996 were reviewed.

RESULTS

Majority of the patients were Chinese (94%), males (81%) with a history of dysphagia (96%), cigarette smoking (84%) and alcohol ingestion (58%). The median age at surgery was 63.6 (range 29 to 81) years. Sixty-four patients had squamous cell carcinoma of the oesophagus and 3 patients had adenocarcinoma. The lower one-third of the oesophagus was the most common site (48.6%) followed by the middle third (46%). Postoperative complications included pneumonia (43.3%), vocal cord paralysis/paresis (19.4%) and anastomotic leakage (17.9%). Thirty-day postoperative mortality was 7.5%. There was an almost equal number of patients undergoing transhiatal (34 patients) and transthoracic approach (33 patients). There was no significant difference in postoperative complications and survival outcome for both approaches. The median survival was 15.3 months after surgery. Tumour features such as depth of involvement and TNM stage were useful in predicting survival (P < 0.05, log-rank test).

CONCLUSIONS

We conclude that the poor outcome of surgical resection (5-year survival rate was 18% by Kaplan-Meier survival plots) was mainly attributed to late presentation (80% patients had T3 or T4 tumour).

Anesthetic management for cesarean section in a pregnant woman with impending acute liver failure--a case report

Acute liver failure includes a constellation of clinical conditions resulting from rapid loss of hepatocyte function. The anesthesiologist may often be asked to anesthetize a patient with acute liver failure before the etiological entity of disease can be completely clarified. Most of the previous reports were concentrated in obstetric or hepatological periodicals. Reports about anesthesia for such patients are scanty. We present a case about a near term pregnant woman with a complication diagnosed as impending acute liver failure, who received total intravenous anesthesia for emergent cesarean section. Pros and cons of different anesthetic techniques for this condition are discussed.

Comparison of subcutaneous hydromorphone with intramuscular meperidine for immediate postoperative analgesia

Intramuscular (i.m.) injection with meperidine is the most common analgesic approach to treat postoperative pain in Taiwan. Hydromorphone (Dilaudid) can provide very potent and rapid analgesic effect through subcutaneous (s.c.) injection. Although hydromorphone is widely used in North America, no study has compared the analgesic efficacy, side effect profiles and patients' satisfaction with the method of injection of hydromorphone s.c. and meperidine i.m. for the immediate post-operative analgesia. In this randomized and double-blind study, 60 female patients scheduled for abdominal total hysterectomy were treated either with 1 mg hydromorphone s.c. (n = 30) or 50 mg meperidine i.m. (n = 30) when they regained consciousness and asked for analgesic treatment in the recovery room. Visual analogue score (VAS) of wound pain was obtained at 0, 10 and 30 min after injection by a blinded observer. The occurrence and severity of nausea, vomiting, dizziness, drowsiness, flatus passage and respiratory depression were recorded. Post-operative analgesia in the ward was maintained by patient-controlled analgesia (PCA) with intravenous morphine. Time to first PCA demand, the number of demands, delivery, delivery/demand ratio and 24 h morphine consumption were documented. We found that VAS was reduced at 10 min and, to a greater extent, at 30 min postinjection in both groups but with no significant difference between the two groups. The occurrence and severity of side effect profiles were similar in both groups except that dizziness was more frequently observed after meperidine injection. Delivery, demand, delivery/demand ratio and 24 hr morphine consumption by PCA were not significantly different between the two groups. Time to first PCA trigger was also similar. Patients receiving hydromorphone s.c. injection exhibited higher satisfactory score than those receiving meperidine i.m. injection. Hydromorphone 1 mg, injected subcutaneously, was as effective as intramuscular meperidine 50 mg while permitting more favorable injection technique and fewer side effects. We suggest that subcutaneous hydromorphone is a good alternative to intramuscular meperidine for postoperative analgesia in the recovery room.

Prevention of hypotension after spinal anesthesia for cesarean section: dextran 40 versus lactated Ringer's solution

BACKGROUND

This study was designed to compare the efficacy of 10% dextran 40 with lactated Ringer's (LR) solution in reducing the incidence and severity of hypotension after spinal anesthesia for Cesarean section.

METHODS

Sixty ASA grade I patients scheduled for Cesarean section were randomized into two groups in a double-blind fashion to receive either 500 ml of dextran 40 or 1000 ml of LR solution prior to induction of spinal anesthesia.

RESULTS

The incidence of hypotension was 16 in 30 (53.3%) in the LR solution group and 8 in 30 (26.7%) in the dextran group (P < 0.05). The required dose of ephedrine for treatment of hypotension was significantly greater in the LR solution group than in the dextran group (15.5 mg versus 3.2 mg, P < 0.05). Neonatal outcome, as determined by Apgar score, was good and similar in both groups.

CONCLUSIONS

We concluded that 500 ml of dextran 40 is more effective than 1000 ml of lactated Ringer's solution in reducing the incidence of hypotension induced by spinal anesthesia.

PAK2 is cleaved and activated during hyperosmotic shock-induced apoptosis via a caspase-dependent mechanism: evidence for the involvement of oxidative stress

Hyperosmotic shock elicits a stress response in mammalian cells and can lead to apoptotic cell death. In the present study, we report that hyperosmotic shock can induce activation of a 36 kDa kinase detected by an in-gel kinase assay in several cell types, including mouse Balb/c 3T3 fibroblasts, and human Hep 3B and A431 cells. This 36 kDa kinase can be recognized by an antibody against the C-terminal region of a family of p21Cdc42/Rac-activated kinases (PAKs) on immunoblot. Further studies with this antibody and a PAK2-specific antibody against the N-terminal region of PAK2 demonstrate that hyperosmotic shock can induce cleavage of PAK2 to generate a 36 kDa C-terminal catalytic fragment in cells. The cleavage and activation of PAK2 was found to be closely associated with both DNA fragmentation and activation of an ICE/CED-3 family cysteine protease termed caspase-3 in hyperosmotically shocked cells. Furthermore, pretreating the cells with two caspase inhibitors (Ac-DEVD-cho and Ac-YVAD-cmk) could inhibit both cleavage/activation of PAK2 and DNA fragmentation induced by hyperosmotic shock. Moreover, all these hyperosmotic shock-induced changes (i.e., activation of caspase-3, cleavage/activation of PAK2, and DNA fragmentation) in cells could be blocked by antioxidants such as ascorbic acid (vitamine C), alpha-tocopherol (vitamine E), dithiothreitol, beta-mercaptoethanol, and glutathione. Taken together, our results show that PAK2 is cleaved and activated via a caspase-dependent mechanism during hyperosmotic shock-induced apoptosis and suggest the involvement of antioxidant-preventable oxidative stress in inducing this process.

Preoperative evaluation and postoperative prediction of hemostatic function with thromboelastography in patients undergoing redo cardiac surgery

BACKGROUND

Patients who receive cardiac procedures, in particular "redo" ones, often suffer complications from massive bleeding, largely due to bypass-induced coagulopathies. Cardiopulmonary bypass (CPB) may cause damage of the blood components, both in terms of quality and quantity. In order to investigate the qualitative changes of blood constituents with special regard to coagulation resulting from the complex insult of previous cardiac surgery, thromboelastography (TEG) was used to analyze the whole clotting process.

METHODS

Seventy-four patients who underwent cardiac surgery with CPB were prospectively studied. Of them, 32 patients received "redo" cardiac surgery. Blood samples for routine laboratory coagulation tests (RCT) and TEG examination were drawn before and after cardiopulmonary bypass. Clinically significant bleeding was defined if the chest tube drainage was greater than 100 ml/h for 3 consecutive h or greater than 300 ml in 1 h during the first 8 h after surgery. Prebypass and postbypass coagulation parameters were compared and the percentage of accuracy, false positive and false negative rate were deduced from calculation.

RESULTS

In the TEG tracings, preoperative alpha angle and maximum amplitude were significantly decreased in the "redo" group when compared with primary group, indicating less competent platelet function and platelet-fibrin interaction. Lower platelet count was also found by conventional coagulation tests in "redo" patients. Postoperatively, higher percentage of excessive hemorrhage was also noted in the "redo" group (42.8% vs. 27.5% in primary group). However, a much lower predictive accuracy was found in "redo" patients in comparison with primary cardiac patients (53.5% vs. 90%).

CONCLUSIONS

We concluded that thromboelastography failed to predict postoperative hemorrhage in "redo" cardiac patients and the graphic recordings derived could not be treated as a guide of transfusion therapy. We thought that inferior preoperative hemostatic status and severer coagulopathy might be responsible for the differences between "redo" and primary cardiac patients.

Proteolytic cleavage and activation of PAK2 during UV irradiation-induced apoptosis in A431 cells

Exposure of mammalian cells to ultraviolet (UV) light elicits a cellular response and can also lead to apoptotic cell death. In this report, we show that a 36-kDa myelin basic protein (MBP) kinase detected by an in-gel kinase assay can be dramatically activated during the early stages of UV irradiation-triggered apoptosis of A431 cells. Immunoblot analysis revealed that this 36-kDa MBP kinase could be recognized by an antibody against the C-terminal regions of a family of p21Cdc42/Rac-activated kinases (PAKs). By using this antibody and a PAK2-specific antibody against the N-terminal region of PAK2 as studying tools, we further demonstrated that UV irradiation caused cleavage of PAK2 to generate a 36-kDa C-terminal catalytic fragment and a 30-kDa N-terminal fragment in A431 cells. The appearance of the 36-kDa C-terminal catalytic fragment of PAK2 matched exactly with the activation of the 36-kDa MBP kinase in A431 cells upon UV irradiation. In addition, UV irradiation also led to activation of CPP32/caspase-3, but not ICH-1L/caspase-2 and ICE/caspase-1, in A431 cells and the kinetics of activation of CPP32/caspase-3 appeared to correlate well with that of DNA fragmentation and of cleavage/activation of PAK2, respectively. Moreover, blockage of activation of CPP32/caspase-3 by pretreating the cells with two specific tetrapeptidic inhibitors for caspases (Ac-DEVD-cho and Ac-YVAD-cmk) could significantly attenuate the extent of cleavage/activation of PAK2 induced by UV irradiation. Collectively, the results demonstrate that cleavage and activation of PAK2 can be induced during the early stages of UV irradiation-triggered apoptosis and indicate the involvement of CPP32/caspase-3 in this process.