Monitoring and treatment practices of childhood asthma in Singapore: a questionnaire study

INTRODUCTION

Asthma is the most common chronic disease in children in Singapore. More than 20 percent of children will have been diagnosed with asthma by the age of 15 years. Most children are seen in the primary care setting, thus it is of value to study the management practices, especially of general practitioners, with comparison to gold standards. The aims of the study were to investigate: (a) Methods of monitoring asthma control; (b) Practices in managing acute exacerbations; and (c) Choice of therapy in maintenance treatment.

METHODS

2,100 questionnaires consisting of 35 questions were sent by post to general practitioners and various paediatric doctors throughout Singapore. 173 valid responses were received and results were compared to the 2006 Global Initiative for Asthma guidelines.

RESULTS

76.3 percent of respondents were general practitioners. 89.1 percent did not use symptom score cards / diaries. 37.6 percent did not use peak-flow meters / spirometers. 83.8 percent used a short-acting beta-agonist in acute exacerbations, but only 41.0 percent used oral corticosteroids in outpatients. A significant number used long-acting beta-agonists (LABA) in combination with inhaled steroids (29.5-41.6 percent) or as monotherapy (5.8-8.7 percent) for maintenance treatment. 91.3 percent never used immunotherapy in practice.

CONCLUSION

Greater usage of diaries / score cards can be encouraged along with objective peak flow / spirometry measurements. Management of acute exacerbations is appropriate but corticosteroids are under-prescribed by most doctors. LABA continues to be prescribed for maintenance despite a lack of established safety profile for infants, along with recommendations that they only be used selectively in patients poorly-controlled by medium-dosage inhaled corticosteroids.

Optic neuritis in Singapore

INTRODUCTION

Optic neuritis (ON) is the commonest optic neuropathy encountered in the younger group of patients from the Singapore Neuro-Ophthalmology Study Group. Previous surveys in Asia and our study suggest that ON in Singapore differs from that in Western populations where the majority of cases are associated with multiple sclerosis (MS).

METHODS

Patients satisfying our entry criteria for ON seen between September 2002 and June 2004 were enrolled in the study. The data collected was recorded in a central database and analysed two years later.

RESULTS

The majority (60 percent) of our patients had anterior ON with optic disc swelling (papillitis), were idiopathic in 49.1 percent, and associated with MS in only 25.5 percent. Bilateral cases comprised 16.4 percent of our series and were usually of the anterior variety and mostly idiopathic, although it is still essential to rule out secondary causes. Recurrent ON is indicative of an underlying disease process.

CONCLUSION

The pattern of ON as seen in Singapore differs from that reported in Caucasian studies and from the seminal Optic Neuritis Treatment Trial. We found a higher incidence of optic disc swelling, i.e. anterior ON (papillitis), and a lesser association with MS; visual recovery is similarly good but our recurrence rate is lower.

Review of orbital imaging

CT and MRI are commonly used in the evaluation of patients with suspected orbital disease. Many different diseases may present within this small anatomical space. The purpose of this article is to present a diagnostic strategy based on a compartment model. Localizing pathology to sinus, bone, extraconal space, muscle cone, intraconal space, optic nerve, globe or lacrimal fossa allows significant reduction in the number of differential diagnoses as these compartments contain different tissues which disease may involve or arise from. Certain diseases may also present in multiple compartments. Common diseases which might present in one or multiple compartments will be discussed.

Lentivirus-mediated gene transfer to the rat, ovine and human cornea

Gene therapy of the cornea shows promise for modulating corneal transplant rejection but the most appropriate vector for gene transfer has yet to be determined. We investigated a lentiviral vector (LV) for its ability to transduce corneal endothelium. A lentivector expressing enhanced yellow fluorescent protein (eYFP) under the control of the Simian virus type 40 early promoter (LV-SV40-eYFP) transduced 80-90% of rat, ovine and human corneal endothelial cells as detected by fluorescence microscopy. The kinetics of gene expression varied among species, with ovine corneal endothelium showing a relative delay in detectable reporter gene expression compared with the rat or human corneal endothelium. Vectors containing the myeloproliferative sarcoma virus promoter or the phosphoglycerate kinase promoter were not significantly more effective than LV-SV40-eYFP. The stability of eYFP expression in rat and ovine corneas following ex vivo transduction of the donor cornea was assessed following orthotopic corneal transplantation. Following transduction ex vivo, eYFP expression was maintained in corneal endothelial cells for at least 28 days after corneal transplantation in the sheep and >60 days in the rat. Thus, rat, ovine and human corneal endothelial cells were efficiently transduced by the LV, and gene expression appeared stable over weeks in vivo.

Central pontine myelinolysis

The case is described of a 46 year old female alcoholic, presenting with confusion, jaundice and reduced level of consciousness. The patient was hyponatraemic on admission and despite gradual correction of serum sodium the patient deteriorated neurologically. Magnetic Resonance Imaging scan of the brain revealed characteristic findings of Central Pontine Myelinolysis (CPM). We provide an overview of the first published cases of CPM. The clinical and pathological features of CPM are described. No specific therapy has been shown to improve outcome; current literature advocates supportive management. Identification of patients at risk and gradual correction of hyponatraemia is recommended.

Microalbuminuria prevalence study in hypertensive type 2 diabetic patients in Malaysia

Microalbuminuria is the earliest indicator of diabetic kidney disease and generalised vascular endothelial dysfunction. The Microalbuminuria Prevalence (MAP) Study was carried out to assess the prevalence of macroalbuminuria, microalbuminuria and normoalbuminuria in Asian hypertensive patients with type 2 diabetes on usual care. This paper presents a subanalysis of data from patients in Malaysia. In 733 analysed patients, the prevalence of macroalbuminuria and microalbuminuria was 15.7% and 39.7%, respectively. The high prevalence of diabetic nephropathy in these high-risk patients is a cause for concern, and the Malaysian Health Care system should be prepared for a pandemic of end-stage renal disease due to diabetic nephropathy.

Electrocardiographical case. A man found unconscious

A 25-year-old man was brought to the emergency room after being found unconscious. Electrocardiography (ECG) showed changes classical of tricyclic antidepressant (TCA) poisoning. These included sinus tachycardia, QTc prolongation, QRS complex widening, right axis deviation and positive R waves in lead aVR. This unique ECG highlights the importance of lead aVR, which often tends to be ignored. Treatment is started based on ECG findings.

Skewing of X-chromosome inactivation in three generations of carriers with X-linked chronic granulomatous disease within one family

BACKGROUND

Chronic granulomatous disease (CGD) is an inherited disorder of the innate immune system characterized by impairment of intracellular microbicidal activity of phagocytes. Mutations in one of the four known NADPH-oxidase components preclude generation of superoxide and related antimicrobial oxidants, leading to the phenotype of CGD. Defects in gp91-phox, encoded by CYBB, lead to X-linked CGD, responsible for approximately 70% of all CGD cases. The aim of the study was to evaluate the hypothesis that age-related skewing of X-chromosome inactivation, as described in several CGD families, is caused by preferential survival of bone marrow clones with an inactive NADPH oxidase.

MATERIALS AND METHODS

We studied the neutrophils from three patients and four carriers in three generations of a Turkish family with X-linked CGD. Carrier detection was carried out by the dihydrorhodamine (DHR)-1,2,3 assay, which measures on a per-cell basis the NADPH oxidase-dependent oxidation of DHR by phagocytes. The X-chromosome inactivation pattern was determined with the HUMARA assay in DNA from leucocytes as well as in DNA from a buccal smear of the four carriers.

RESULTS

The three patients were identified by a negative DHR test, and the mutation in their CYBB gene was characterized by DNA sequencing. Moreover, we found an age-related degree of skewing of X-chromosome inactivation in the leucocytes of the four X-CGD carriers, both at the protein level (NADPH oxidase activity) and at the DNA level (HUMARA assay). However, similar skewing of X-chromosome inactivation was found in the buccal DNA from these women.

CONCLUSIONS

These novel findings indicate that the age-related degree of skewing was probably a chance finding, not related to preferential survival of NADPH oxidase-deficient precursor cells, because this enzyme is not expressed in (buccal) epithelial cells.

Validation of various osteoporosis risk indices in elderly Chinese females in Singapore

INTRODUCTION

This study aimed to compare the sensitivity and specificity of various published indices for identifying elderly Chinese females at risk of osteoporosis in Singapore.

METHODS

The indices considered were the Simple Calculated Osteoporosis Risk Estimation (SCORE), the Osteoporosis Risk Assessment Instrument (ORAI), the Age Bulk One or Never Estrogens (ABONE), body weight (WEIGHT), and the Osteoporosis Self-Assessment Tool for Asians (OSTA). Altogether, 135 postmenopausal Chinese female subjects aged 55 years and older participated in the study, and their bone mineral density (BMD) was measured with dual-energy x-ray absorptiometry. Subjects were classified as osteoporotic if their femoral neck BMD T-score was -2.5 or lower. Receiver operating characteristic (ROC) curves were generated to determine the indices' cut-off points, sensitivity, and specificity.

RESULTS

OSTA had the highest discriminatory power, with an estimated area under the ROC curve of 0.82. This was followed by SCORE (0.80), WEIGHT (0.78), ORAI (0.76), and ABONE (0.70). At the cut-off point of -2, OSTA achieved sensitivity and specificity of 91% and 59%, respectively.

CONCLUSION

The study showed that OSTA is an effective index for identifying postmenopausal women at risk for osteoporosis.

Differential expression of splice variant and wild-type parkin in sporadic Parkinson's disease

BACKGROUND

Altered splicing of parkin under cellular stress could lead to changes in gene expression and altered protein activity. The causative role of parkin in sporadic Parkinson's disease (PD) is unknown.

OBJECTIVES

We described a parkin splice variant (SV) in the substantia nigra and leukocytes of sporadic PD patients. Using a case control methodology, we investigated the exon 4 SV (E4SV) and wild-type parkin expression in the leukocytes of sporadic PD patients and healthy individuals.

METHODS/RESULTS

We identified a parkin E4SV in the substantia nigra and leukocytes of sporadic PD patients and controls by reverse transcriptase-polymerase chain reaction (PCR). The exon 4 (122 bp) deletion resulted in a reading frame shift over the junction of exons 3-5 and a stop codon (tga) 17 bp downstream from exon 3. The translated truncated protein was associated with a total loss of the two-RING finger functional domain. Utilizing TaqMan real-time PCR with probes located across the junction of exons 3-4 or 3-5, we demonstrated an over-expression of E4SV/wild-type parkin ratio in the leukocytes of sporadic PD patients compared to age-, gender-, and race-matched controls (p<0.0005). A multivariate regression analysis demonstrated that the ratio of E4SV/wild-type parkin expression increased with age in PD patients, but this was not observed in the controls (p<0.0005).

CONCLUSION

The relative expression of E4SV/wild type parkin was increased in sporadic PD compared to healthy controls. Based on our observations, further functional studies to determine the pathophysiologic role of E4SV in sporadic PD patients will be of importance.

A prospective randomized controlled trial of suction versus non-suction to the under-water seal drains following lung resection

OBJECTIVE

Practice varies as to whether or not suction is applied to under-water seal drains following lung surgery. We tested the null hypothesis that there is no difference with respect to air leak duration.

METHODS

Patients undergoing thoracotomy or video assisted thoracoscopic surgery for lobectomy or wedge resection had either low-pressure suction or no suction applied to their underwater seal bottles postoperatively. Patients were allocated using minimization, a method of unbiased allocation ensuring balance between the arms of a trial with respect to known or suspected confounding factors. The trial was powered for duration of air leak. If an air leak persisted on the 7th post-operative day, the surgeon determined further management. Kaplan-Meier survival analysis of air leak duration and a log rank test were performed on an intention-to-treat basis, with observations censored at 144h (6 complete days).

RESULTS

Of the 254 patients that entered the trial, data were available for analysis for 239 (123 no-suction and 116 suction). There was no significant difference in the cumulative persistence of air leaks between the two groups (P=0.62) and inspection of the Kaplan-Meier curves suggests that any difference is negligible.

CONCLUSIONS

Applying suction to the underwater seal drains following lung surgery makes no difference in terms of air leak duration. In the light of this finding we have adopted a uniform policy of no suction being applied to the underwater seal, from the time of surgery, unless a specific clinical judgment is made to use it. The anticipated gains are that this will reduce work and cost and aid mobilization.

Alvarado score: an admission criterion in patients with right iliac fossa pain

Appendicitis is an important differential diagnosis in patients with right iliac fossa pain. The diagnosis in patients with equivocal signs can be difficult. Many patients with suspected appendicitis are admitted for observation. We studied the Alvarado scores of 175 patients who presented to the emergency department with right iliac fossa pain and found that patients with scores of 4 or less did not have appendicitis. We also present an algorithm incorporating the Alvarado score for patients with suspected appendicitis.

Fragile X premutation alleles in SCA, ET, and parkinsonism in an Asian cohort

Among 367 subjects, the authors analyzed 167 patients with essential tremor, sporadic progressive cerebellar ataxia, multiple-system atrophy, and atypical parkinsonism and 200 healthy control subjects for FMR1 premutation alleles. None of the subjects carried alleles within the premutation range. These findings suggest that in the absence of other supportive clinical or imaging features, the cost-effectiveness of routine fragile X tremor/ataxia syndrome screening in this Asian cohort with movement disorders was low.

Evaluation of four warming procedures to minimise heat loss induced by anaesthesia and surgery in dogs

OBJECTIVE

To evaluate the efficiency of four warming procedures, introduced after anaesthetic induction and continued during surgery, in minimising heat loss in anaesthetised dogs.

DESIGN

Dogs were paired. One of each pair was a control; the other was subjected to one of four warming procedures.

METHODS

Ninety-six dogs were involved in total. Pairs of dogs were matched for breed, hair length, and type of surgical procedure and placed adjacent to each other in a large temperature-controlled surgical theatre. One dog within each pair was assigned to one of four warming procedures that commenced immediately after anaesthetic induction. Group 1 (11 pairs) were placed on a purpose-designed prewarmed (41 degrees C) electrically heated pad. Group 2 (18 pairs) were placed on a prewarmed electric heat pad (41 degrees C), cocooned by four wrapped water bottles (initially 41 degrees C) and subjected to radiant heat (150 watt lamp placed 50 cm away from the head of the dog). Group 3 (11 pairs) were surrounded by a forced air warming mattress (set at 43 degrees C). Group 4 (8 pairs) were connected via the anaesthetic breathing circuit to a heater/humidifier (set at 41 degrees C). Rectal temperature measurements were recorded every 15 min for the first 3 h of anaesthesia. The fall in rectal temperature of the control dog was subtracted from the fall in temperature of the treatment dog and this measurement was used to assess the efficacy of the various warming procedures.

RESULTS

The mean rectal temperature of unheated 'control' dogs decreased 1.9 +/- 0.6, 1.4 +/- 0.4 and 1.1 +/- 0.4 degrees C over the first, second and third hour respectively. After 3 h the temperature fall differential for all groups were 0.7 +/- 0.7 (Group 1), 3.1 +/- 1.1 (Group 2), 2.4 +/- 1.1 (Group 3) and 1.0 +/- 1.1 degrees C (Group 4). Thus the group 2 procedure was the most successful in preventing a drop of temperature followed by groups 3, 4 and 1.

CONCLUSION

Large dogs undergo significant reduction in core body temperature especially during the first 2 h of anaesthesia and surgery. Supplementary warming substantially reduces this fall in body temperature, although certain warming procedures were found to be more effective than others.

Alpha-synuclein haplotypes implicated in risk of Parkinson's disease

The authors examined four- and six-loci haplotype constructs (from five single nucleotide polymorphisms and three microsatellite regions) of the alpha-synuclein gene in patients with Parkinson's disease (PD) and controls in an ethnic Chinese population. Logistic regression analysis demonstrated an association of NACP-Rep1 (p = 0.002) and L478 (p < 0.0001) with risk of PD after correction for the effects of age, sex, and the other polymorphic loci. Specific four-loci and six-loci haplotypes were significantly associated with an increased or decreased risk of PD.

Dose-dependent protective effect of coffee, tea, and smoking in Parkinson's disease: a study in ethnic Chinese

INTRODUCTION

Few studies have examined the relationship of coffee and tea in Parkinson's disease (PD). The potential protective effect of coffee intake and risk of PD has not been studied in a Chinese population. There is a high prevalence of caffeine takers among Chinese in our population.

OBJECTIVE

We undertook a case control study to examine the relationship between coffee and tea drinking, cigarette smoking, and other enviromental factors and risk of PD among ethnic Chinese in our population.

METHODS AND RESULTS

300 PD and 500 population controls were initially screened. Two hundred case control pairs matched for age, gender, and race were finally included in the analysis. Univariate analysis revealed significant association of PD with coffee drinking (p<0.0005), tea drinking (p=0.019), alcohol drinking (p=0.001), cigarette smoking (p<0.0005), and exposure to heavy metals (p=0.006). Conditional logistic regression analysis demonstrated that amount of coffee drunk (OR 0.787, 95%CI 0.664-0.932, p=0.006), amount of tea drunk (OR 0.724, 95%CI 0.559-0.937, p=0.014), number of cigarettes smoked (OR 0.384, 95%CI 0.204-0.722, p=0.003), history of heavy metal and toxin exposure (OR 11.837, 95%CI 1.075-130.366, p=0.044), and heart disease (OR 5.518, 95%CI 1.377-22.116, p=0.016) to be significant factors associated with PD. One unit of coffee and tea (3 cups/day for 10 years) would lead to a 22% and 28% risk reduction of PD. One unit of cigarette smoke (3 packs/day for 10 years) reduced the risk of PD by 62%.

CONCLUSIONS

We demonstrated a dose-dependent protective effect of PD in coffee and tea drinkers and smokers in an ethnic Chinese population. A history of exposure to heavy metals increased the risk of PD, supporting the multifactorial etiologies of the disease.

Optical emission from excess Si defect centers in Si nanostructures

Four groups of Si nanostructures with and without beta-SiC nanocrystals were fabricated for clarifying the origin of a blue emission with a double-peak structure at 417 and 436 nm. Spectral analyses and microstructural observations show that the blue emission is related to the existence of excess Si atoms in these Si nanostructures. The energy levels of electrons in Si nanocrystals with vacancy defects formed from the excess Si atoms are calculated and the characteristics of the obtained density of states coincide with the observed double-peak emission. The present work provides a possible mechanism of the blue emission in various Si nanostructures.

Selective pressure has not acted against hypercoagulability alleles in high-altitude Amerindians

Elevated hematocrit increases blood oxygen carrying capacity in high-altitude populations, but blood viscosity and coaguability may increase concomitantly. Alleles of the beta-fibrinogen gene (FGB) associated with lower fibrinogen levels are more common in highland Amerindians (Quechua) than lowland Amerindians (Na-Dene). Although genetic drift could account for this, selection may have acted against transmission of hypercoagulability alleles at high altitude. To test this hypothesis, we compared allele frequencies between Quechua and more closely related lowlanders (Maya) at loci in the genes encoding beta-fibrinogen (FGB), factors V (F5), VII (F7) and XIII (F13), alpha2-integrin (ITGA2) and plasminogen activator inhibitor type 1 (PAI-1; SERPINE1). No significant differences in allele frequencies were found except 485arg in the gene encoding factor V, which was more common in the Quechua. These data do not support the hypothesis that selection has acted to eliminate alleles associated with hypercoagulability in Andean highlanders.

Monoamine oxidase B polymorphism, cigarette smoking and risk of Parkinson's disease: a study in an Asian population

Cigarette smoking is associated with reduced monoamine oxidase B (MAO B) activity. Polymorphisms of the MAO B gene may modify the relationship between smoking and Parkinson's Disease (PD). We examined the association of MAO B intron 13 G/A polymorphism and risk of PD, and the modulation of the polymorphism on smoking and PD in an Asian study population in Singapore. Two hundred and thirty PD patients (mean age 66.0 +/- 9.4 years, 63% men) and 241 age, gender, and race matched controls (mean age 64 +/- 9.2 years, 58.9% males) were studied. The frequency of G and A alleles in PD and controls was; 66/315 (21.0%) vs. 73/340 (21.5%) and 249/315 (79.0%) vs. 267/340 (78.5%). For women, the genotype frequency in PD and controls was; GG: 7/85 (8.2%) vs. 8/99 (8.1%); GA: 25/85 (29.4%) vs. 27/99 (27.3%); AA: 53/85 (62.4%) vs. 64/99 (64.6%). For men, allele frequency in PD and controls was; A: 118/145 (81.4%) vs. 112/142 (78.9%) and G: 27/145 (18.6%) vs. 30/142 (21.1%). The allele and genotype frequencies were not significantly different between young and late onset PD. The frequency of "ever" smokers in PD and controls was 31/230 (13.5%) vs. 52/241 (21.6%), P = 0.02. A stepwise logistic regression analysis did not reveal any interaction of smoking and the G allele and risk of PD. The MAO B G/A genotype frequency in our Asian population was quite different from Caucasians suggesting that ethnicity specific effects need to be considered in evaluating gene-environmental interaction.

Ethnic differences in acute myocardial infarction in Singapore

AIMS

We compare the myocardial infarction (MI) event and mortality rates among Chinese, Malay and Indian residents of Singapore.

METHODS

Residents, aged 20 to 64 years, with an MI event were identified from hospital discharge listings, postmortem reports, and the Registry of Births and Deaths. All pathology laboratories flagged patients with elevated creatine phosphokinase (CPK) levels. Modified MONICA (multinational monitoring of trends and determinants in cardiovascular disease) criteria were used for determining MI events.

RESULTS

From 1991 to 1999, 12 481 MI events were identified. Chinese patients were older and less likely to have typical symptoms or previous MI. Malays had the highest peak CPK level. Among all three ethnic groups, MI event and age-adjusted case-fatality rates declined. Compared with Chinese, MI event rates were >2-fold and >3-fold higher, and age-standardized coronary mortality rates were 2.4 and 3.0 higher times for Malays and Indians, respectively. Malays have the highest 3.1-year case-fatality, with an adjusted hazard ratio of 1.26 (95% confidence interval, 1.14 to 1.38) compared with Chinese.

CONCLUSION

We found strong ethnic differences in MI event, case-fatality and coronary mortality rates among the three ethnic groups in Singapore. While Indians have the greatest MI event rates, Malays have the highest case-fatality.

Persistence of the antihypertensive efficacy of amlodipine and nifedipine GITS after two 'missed doses': a randomised, double-blind comparative trial in Asian patients

Suboptimal management of hypertension is often a result of poor patient compliance in the form of missed doses of their antihypertensive medication. This multicentre, randomised, double-blind, parallel-group trial was designed to compare the persistence of the antihypertensive efficacy of the amlodipine and nifedipine gastrointestinal therapeutic system (GITS) after two 'missed doses', and also to compare the drugs' overall efficacy and safety in Asian patients with mild-to-moderate essential hypertension. Following a 2-week placebo run-in period, 222 patients were randomised to receive either amlodipine (5 mg daily, increased after 6 weeks if necessary to 10 mg daily, n=109) or nifedipine GITS (30 mg daily, increased after 6 weeks if necessary to 60 mg daily; n=113) for 12 weeks. A placebo was then substituted for further 2 days with continuous ambulatory blood pressure (BP) monitoring. The increases in the last 9 h of mean ambulatory BP on day 2 after treatment withdrawal were significantly less with amlodipine than with nifedipine GITS: 4.4+/-7.0 vs 11.2+/-11.3 mmHg for systolic BP (P<or=0.0001) and 2.4+/-6.3 vs 6.0+/-6.0 mmHg for diastolic BP (P<or=0.0002). Significant differences between the two drugs in mean 24-h ambulatory BP levels were already evident on day 1 after withdrawal, even though there were no significant differences on the final day of treatment. No differences in safety parameters were observed, and neither drug caused any serious or severe treatment-related adverse events. In conclusion, amlodipine provides greater protection than nifedipine GITS against loss of BP control following missed doses.

Simultaneous determination of inorganic anions, carboxylic and aromatic carboxylic acids by capillary zone electrophoresis with direct UV detection

Co-electroosmotic capillary zone electrophoresis (CZE) with direct UV detection was developed for simultaneous determination of inorganic anions, carboxylic and aromatic carboxylic acids. These solutes were separated using a 30 mM phosphate buffer containing 1.0 mM tetradecyltrimethylammonium bromide (TTAB) and 20% (v/v) acetonitrile at pH of 6.5 and directly detected by UV at 190 nm. Calibration curves were linear in the range 0.01-2.0 mM, depending of the solutes. The detection limits ranged from 1.0 to 8.0 microM and the relative standards deviations (n=5) in range from 1.9 to 3.6% for the peak area. The proposed method was used to determine inorganic anions and carboxylic and aromatic acids in soil and plant tissue extracts.

Calmodulin-binding and autoinhibitory domains of Acanthamoeba myosin I heavy chain kinase, a p21-activated kinase (PAK)

The sequence homology between Acanthamoeba myosin I heavy chain kinase (MIHCK) and other p21-activated kinases (PAKs) is relatively low, including only the catalytic domain and a short PAK N-terminal motif (PAN), and even these regions are not highly homologous. In this paper, we report the expression in insect cells of full-length, fully regulated Acanthamoeba MIHCK and further characterize the regulation of this PAK by Rac, calmodulin, and autoinhibition. We map the autoinhibitory region of MIHCK to its PAN region and show that the PAN region inhibits autophosphorylation and kinase activity of unphosphorylated full-length MIHCK and its expressed catalytic domain but has very little effect on either when they are phosphorylated. These properties are similar to those reported for mammalian PAK1. Unlike PAK1, MIHCK is activated by Rac only in the presence of phospholipid. However, peptides containing the PAN region of MIHCK bind Rac in the absence of lipid, and Rac binding reverses the inhibition of the MIHCK catalytic domain by PAN peptides. Our data suggest that a region N-terminal to PAN is required for optimal binding of Rac. Also unlike mammalian PAK, phospholipid stimulation of Acanthamoeba MIHCK and Dictyostelium MIHCK) (which is also a PAK) is inhibited by Ca(2+)-calmodulin. In contrast to Dictyostelium MIHCK, however, Ca(2+)-calmodulin also inhibits Rac-induced activity of Acanthamoeba MIHCK. The basic region N-terminal to PAN is essential for calmodulin binding.

[Hemodynamics following + Gz stress in dog]

AIM

To investigate the character of hemodynamics following + Gz stress in dog.

METHODS

Nine anesthesia dogs were exposed to 5, 7 and 9 + Gz stress, 90 s at peak G. Each animal was instrumented to measure left ventricular pressure, thoracic aorta pressure, iliac arterial pressure,common carotid artery flow (CCAF) and ECG.

RESULTS

(1) Heart rate, CCAF and blood pressure at any place increased. They were greater than those before + Gz stress (P < 0.05). (2) There were much more arrhythmias following high + Gz stress. Most of arrhythmias were junctional premature beats, ventricular premature beats. 80% arrhythmias occurred within 3 min following + Gz stress. (3) Blood pressure appeared the highest in the second min following + Gz stress.

CONCLUSION

Great hemodynamic disturbance happened following high + Gz stress. There might were reperfusion arrhythmias. Protective measures should been noted following high + Gz stress.

[Intramandibular course and anatomic structure of the inferior alveolar nerve canal]

OBJECTIVE

To study the intramandibular course and anatomic structure of mandibular canal.

METHODS

The intramandibular course of mandibular canal and its dimension were measured in 15 adults mandibles with teeth; the relationship between blood vessel and nerve was observed in 4 fresh samples in which the artery was filled.

RESULTS

The mandibular canal was close to the lingual side and the inferior margin of the mandible. The blood vessel lay above nerve in the mandibular canal.

CONCLUSIONS

In implant operation performed according to normal anatomy, injury to inferior alveolar nerve may be avoided. Hemorrhage is the earliest manifestation suggesting that continuing drill may damage the inferior alveolar nerve.

A role for frizzled 3 in neural crest development

Wnts are a large family of secreted molecules implicated in numerous developmental processes. Frizzled proteins are likely receptors for Wnts and are required for Wnt signaling in invertebrates. A large number of vertebrate frizzled genes have also been identified, but their roles in mediating specific responses to endogenous Wnts have not been well defined. Using a functional assay in Xenopus, we have performed a large screen to identify potential interactions between Wnts and frizzleds. We find that signaling by Xwnt1, but not other Wnts, can be specifically enhanced by frizzled 3 (Xfz3). As both Xfz3 and Xwnt1 are highly localized to dorsal neural tissues that give rise to neural crest, we examined whether Xfz3 mediates Xwnt1 signaling in the formation of neural crest. Xfz3 specifically induces neural crest in ectodermal explants and in embryos, similar to Xwnt1, and at lower levels of expression, synergizes with Xwnt1 in neural crest induction. Furthermore, loss of Xfz3 function, either by depletion with a Xfz3-directed morpholino antisense oligonucleotide or by expression of an inhibitory form of Xfz3 (Nfz3), prevents Xwnt1-dependent neural crest induction in ectodermal explants and blocks neural crest formation in whole embryos. These results show that Xfz3 is required for Xwnt1 signaling in the formation of the neural crest in the developing vertebrate embryo.

Kermit, a frizzled interacting protein, regulates frizzled 3 signaling in neural crest development

Wnts are a family of secreted glycoproteins that are important for multiple steps in early development. Accumulating evidence suggests that frizzled genes encode receptors for Wnts. However, the mechanism through which frizzleds transduce a signal and the immediate downstream components that convey that signal are unclear. We have identified a new protein, Kermit, that interacts specifically with the C-terminus of Xenopus frizzled-3 (Xfz3). Kermit is a 331 amino acid protein with a central PDZ domain. Kermit mRNA is expressed throughout Xenopus development and is localized to neural tissue in a pattern that overlaps Xfz3 expression temporally and spatially. Co-expression of Xfz3 and Kermit results in a dramatic translocation of Kermit to the plasma membrane. Inhibition of Kermit function with morpholino antisense oligonucleotides directed against the 5′ untranslated region of Kermit mRNA blocks neural crest induction by Xfz3, and this is rescued by co-injection of mRNA encoding the Kermit open reading frame. These observations suggest that Kermit is required for Wnt/frizzled signaling in neural crest development. To the best of our knowledge, Kermit is the first protein identified that interacts directly with the cytoplasmic portion of frizzleds to modulate their signaling activity.

Dysregulation of integrin-linked kinase (ILK) signaling in colonic polyposis

Mutation of the adenomatous polyposis coli (APC) gene and the subsequent dysregulation of beta-catenin are well-documented abnormalities in familial adenomatous polyposis (FAP), as well as sporadic polyposis. Intriguingly, overexpression of the integrin-linked kinase (ILK) has been shown to modulate beta-catenin subcellular localization and function. However, the significance of this finding for human carcinogenesis remains unclear. Here, we report the increased biochemical activity and expression of ILK protein in polyps from FAP patients. Furthermore, dramatic increases in ILK immunoreactivity were observed in all abnormal crypts from sporadic polyps, when compared with the normal appearing crypts within the same resected specimens. As sulindac and aspirin are the two most important therapeutic/chemopreventative agents demonstrated in colorectal carcinogenesis, in both humans and animals, further investigation revealed that these non-steroidal anti-inflammatory drugs (NSAIDs) target ILK and ILK-mediated events in vivo. These include inhibition of, both the biochemical activation of ILK, inhibition of serine 9 GSK3beta phosphorylation and the enhancement of TCF-4 transcriptional activity. In conclusion, ILK protein hyperexpression appears to be an early event in colonic polyposis. Additionally, ILK signaling is shown to undergo modulation by sulindac (and aspirin) for the first time, indicating that it is likely to be one of the targets affected by these agents in vivo.

Spiro(indoline-3,4'-piperidine) growth hormone secretagogues as ghrelin mimetics

A series of small molecules derived from MK-0677, a potent synthetic GHS, mimicking the N-terminal Gly-Ser-O-(n-octanoyl)-L-Ser-Phe segment of ghrelin was synthesized and tested in a binding and in a functional assay measuring intracellular calcium elevation in HEK-293 cells expressing hGHSR1a. Replacement of Phe in this tetrapeptide with a spiro(indoline-3,4'-piperidine) group, Gly-Ser with 2-aminoisobutyric acid, and O-(n-octanoyl)-L-Ser with O-benzyl-D-Ser provided synthetic GHS agonists with similar functional potency as ghrelin.

Proteomic detection of changes in protein synthesis induced by NGX6 transfected in human nasopharyngeal carcinoma cells

In the previous study, we cloned a new gene, named NGX6, related to nasopharyngeal carcinoma (NPC) at 9p. To study its function in the pathogenesis of NPC, we have investigated changes in protein synthesis between NPC cell line HNE1 and that transfected with the gene. Using high-resolution two-dimensional electrophoresis, we found that 22 protein spots showed variations that were significant and reproducible. Analysis of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and database searches identified seven proteins that were upregulated and seven proteins that were downregulated. These proteins included Fas, zinc-finger protein (ZNF), RAB, and Ah receptor-interacting protein (AIP). The functional implications of the identified proteins are discussed.