Sublethal thermal stress promotes migration and invasion of thyroid cancer cells

OBJECTIVE

Radiofrequency ablation is a viable option in the treatment of benign thyroid nodules. Some reports suggest that thermal ablation may also be safe for the management of low-risk thyroid cancer. In this study, we applied transient heat treatment to thyroid cancer cells to mimic clinical scenarios in which insufficient ablation leads to incomplete eradication of thyroid cancer.

METHODS

Differentiated thyroid cancer cell lines B-CPAP, TPC-1, and FTC-133 were subjected to heat treatment at different temperatures for 10 min. Effects on cell growth, clonogenicity, wound healing assay, and Transwell invasion were determined.

RESULTS

Heat treatment at 45°C or higher reduced cell growth, whereas viability of thyroid cancer cells was not changed after heat treatment at 37, 40, or 42°C. Heat treatment at 40°C increased the number of colony formations by 16% to 39%. Additionally, transient heat treatment at 40°C resulted in a 1.75-fold to 2.56-fold higher migratory activity than treatment at 37°C. Invasive capacity was increased after heat treatment, ranging from 115% to 126%. Expression of several epithelial-mesenchymal transition markers, including ZEB1, N-cadherin, and MMP2, was upregulated following heat treatment at 40°C.

CONCLUSION

We for the first time demonstrate that sublethal thermal stress may increase clonogenicity, migration, and invasion of thyroid cancer cells.

SOX4 is a pivotal regulator of tumorigenesis in differentiated thyroid cancer

The SOX family consists of about 20 transcription factors involved in embryonic development, reprogramming, and cell fate determination. In this study, we demonstrated that SOX4 was significantly upregulated in differentiated thyroid cancer. Immunohistochemical analysis revealed that high SOX4 expression was associated with papillary histology, extrathyroidal extension, lymph node metastasis, and advanced disease stage. Patients whose tumors exhibited high SOX4 expression had a shorter recurrence-free survival, though significance was lost in multivariate Cox regression analysis. SOX4 silencing in thyroid cancer cells slowed cell growth, attenuated clonogenicity, and suppressed anoikis resistance. Additionally, SOX4 knockdown impeded xenograft tumor growth in nude mice. Knockdown of SOX4 expression was accompanied by reduced phosphorylation of AKT and ERK. Furthermore, CRABP2 expression correlated with SOX4 expression, and SOX4 silencing decreased CRABP2 expression and its downstream effectors such as integrin β1 and β4. These results indicate that SOX4 has both prognostic and therapeutic implications in differentiated thyroid cancer, and targeting SOX4 may modulate tumorigenic processes in the thyroid.

Downregulation of cellular retinoic acid binding protein 1 fosters epithelial-mesenchymal transition in thyroid cancer

Cellular retinoic acid binding protein 1 (CRABP1) participates in the regulation of retinoid signaling. Previous studies showed conflicting results regarding the role of CRABP1 in tumor biology, including protumorigenic and tumor-suppressive effects in different types of cancer. Our bioinformatics analyses suggested that CRABP1 expression was downregulated in thyroid cancer. Ectopic expression of CRABP1 in thyroid cancer cells suppressed migratory and invasive activity without affecting cell growth or cell cycle distribution. In transformed normal thyroid follicular epithelial cells, silencing of CRABP1 expression increased invasiveness. Additionally, CRABP1 overexpression was associated with downregulation of the mesenchymal phenotype. Kinase phosphorylation profiling indicated that CRABP1 overexpression was accompanied by a decrease in phosphorylation of epidermal growth factor (EGF) receptor and downstream phosphorylation of Akt, STAT3, and FAK, which were reversed by exogenous EGF treatment. Immunohistochemical analysis of our tissue microarrays revealed an inverse association between CRABP1 expression and disease stage of differentiated thyroid cancer. Taken together, our results suggest that CRABP1 expression is aberrantly lost in thyroid cancer, and this downregulation promotes the epithelial-mesenchymal transition at least partly through modulating EGF receptor signaling.

Impact of completion thyroidectomy on postoperative recovery in patients with differentiated thyroid cancer

While an increasing number of patients now undergo lobectomy for low-risk differentiated thyroid cancer, a subset of patients require completion thyroidectomy to facilitate radioactive iodine therapy. Completion thyroidectomy is generally as safe as the initial operation, but a previous study showed that a longer hospitalization is required for completion thyroidectomy. In this study, we reviewed 61 consecutive patients who had been treated with an initial lobectomy and subsequent completion thyroidectomy at our institution from 2012 to 2021. We detected a changepoint in 2016 for the proportion of patients who were treated with a thyroid lobectomy (Pettitt's test P = 0.049). The rate of completion thyroidectomy remained stable throughout the study period. There was no difference in operating time, intraoperative blood loss, perioperative drop in calcium levels, and postoperative hospital stay between surgeries. The patients reported higher pain scores on the day of operation (P = 0.007) and the postoperative day 1 (P = 0.022). Occult papillary microcarcinomas were identified in the contralateral thyroid lobe in 13 (21%) patients. Multifocality was the only predictor for residual malignancy in multivariate regression. In conclusion, patients with differentiated thyroid cancer experienced more pain in the immediate postoperative period following completion thyroidectomy. Hospital stays do not change with appropriate opioid-free pain control.

CRABP2 Is Associated With Thyroid Cancer Recurrence and Promotes Invasion via the Integrin/FAK/AKT Pathway

Cellular retinoic acid-binding protein 2 (CRABP2) participates in retinoid partitioning between different nuclear receptors. Recently, we identified that CRABP2 is one of the progression-associated genes in thyroid cancer. To explore the prognostic and functional significance of CRABP2, immunohistochemical analysis was performed in thyroid tissues and neoplasms. Overexpression of CRABP2 was observed in malignant thyroid neoplasms but not in benign thyroid lesions. CRABP2 expression was an independent predictive factor for recurrence-free survival in patients with differentiated thyroid cancer. Knockdown of CRABP2 reduced the sensitivity of thyroid cancer cells to retinoic acid. Importantly, CRABP2 expression in thyroid cancer cells was associated with epithelial-mesenchymal transition properties, including anoikis resistance, migration, and invasion capacity. Furthermore, invasion promoted by CRABP2 was mediated at least partly by the integrin/focal adhesion kinase/AKT pathway. In summary, CRABP2 expression is upregulated in thyroid cancer with adverse prognostic implications. The invasion-stimulating effects appear independent of canonical retinoic acid signaling and may serve as a potential therapeutic target.

ACLY inhibitors induce apoptosis and potentiate cytotoxic effects of sorafenib in thyroid cancer cells

PURPOSE

ATP-citrate lyase (ACLY) is a critical enzyme at the intersection of glucose and lipid metabolism. ACLY is often upregulated or activated in cancer cells to accelerate lipid synthesis and promote tumor progression. In this study, we aimed to explore the possibility of utilizing ACLY inhibition as a new strategy in the treatment of thyroid cancer.

METHODS

Bioinformatics analysis of the public datasets was performed. Thyroid cancer cells were treated with two different ACLY inhibitors, SB-204990 and NDI-091143.

RESULTS

Bioinformatics analysis revealed that ACLY expression was increased in anaplastic thyroid cancer. In thyroid cancer cell lines FTC-133 and 8505C, ACLY inhibitors suppressed monolayer cell growth and clonogenic ability in a dose-dependent and time-dependent manner. Flow cytometry analysis showed that ACLY inhibitors increased the proportion of sub-G1 cells in the cell cycle and the number of annexin V-positive cells. Immunoblotting confirmed caspase-3 activation and PARP1 cleavage following treatment with ACLY inhibitors. Compromised cell viability could be partially rescued by co-treatment with the pan-caspase inhibitor Z-VAD-FMK. Additionally, we showed that ACLY inhibitors impeded three-dimensional growth and cell invasion in thyroid cancer cells. Isobolograms and combination index analysis indicated that ACLY inhibitors synergistically potentiated the cytotoxicity rendered by sorafenib.

CONCLUSIONS

Targeting ACLY holds the potential for being a novel therapeutic strategy for thyroid cancer.

Aberrant Expression of Thymosin Beta-4 Correlates With Advanced Disease and BRAF V600E Mutation in Thyroid Cancer

Thymosin beta-4 (TMSB4X) was recently identified as a differentially expressed gene between malignant and non-malignant thyroid cells via single-cell RNA sequencing. In the present study, we aimed to study the immunostaining pattern of TMSB4X in benign and malignant thyroid neoplasms. Immunohistochemical analysis revealed that normal thyroid tissue or benign thyroid disorders exhibited undetectable immunoreactivity against TMSB4X except for positive staining of inflammatory infiltrates and stromal cells associated with autoimmune thyroid disease. By contrast, overexpression of TMSB4X was observed in a variety of thyroid malignancies, including papillary, follicular, poorly differentiated, and undifferentiated thyroid cancer. Among 141 patients with differentiated thyroid cancer, higher TMSB4X expression was associated with papillary tumor type, extrathyroidal extension, lymph node metastasis, and BRAF V600E mutation. The results were consistent with those from the public transcriptomic datasets. In summary, TMSB4X expression was aberrantly increased in various types of thyroid cancer, and higher TMSB4X expression was correlated with advanced disease characteristics. Thymosin beta-4 may be a novel downstream effector of the BRAF V600E mutation.

SREBP1 promotes invasive phenotypes by upregulating CYR61/CTGF via the Hippo-YAP pathway

Aberrant lipid metabolism provides bioenergetic, biosynthetic, and redox supplies to cancer cells. Previous studies have reported differential lipid profiling in thyroid malignancies. Sterol regulatory element-binding protein 1 (SREBP1), encoded by the SREBF1 gene, is a master regulator of cellular lipid homeostasis. The clinical and functional significance of SREBP1 in thyroid cancer is not well understood. Here, we showed that SREBP1 expression is significantly upregulated in invasive thyroid cancer than in normal thyroid tissue or benign thyroid nodules. High tumoral SREBP1 expression was associated with extrathyroidal extension, advanced disease stage, and shorter disease-specific survival in patients with differentiated thyroid cancer. SREBP1 overexpression significantly increased the oxygen consumption rate, filopodia formation, and migratory and invasive capacities of thyroid cancer cells. Knockdown of SREBF1 or treatment with an SREBP1 activation inhibitor fatostatin had the opposite effect. RNA-Seq analysis showed that modulation of SREBP1 expression was accompanied by corresponding changes in the expression of epithelial-mesenchymal transition markers and CYR61/CTGF. SREBP1-facilitated cell invasion could be abrogated by treatment with a YAP inhibitor such as verteporfin or genetic silencing of CYR61 or CTGF. In summary, SREBP1 upregulation can be used as a prognostic indicator for thyroid cancer and SREBP1 overexpression is involved in cancer invasiveness, at least partly, through upregulation of CYR61/CTGF via the Hippo-YAP pathway.

Learning curve analysis of radiofrequency ablation for benign thyroid nodules

BACKGROUND

Radiofrequency ablation (RFA) has been increasingly accepted as an alternative to surgery in the treatment of symptomatic benign thyroid nodules. However, the learning curve of thyroid RFA has yet to be defined. We hypothesized a temporal relationship between proficiency of the skill and midterm volume reduction.

METHODS

Consecutive patients who underwent RFA and had at least a six-month follow-up were identified from an institutional database. The cumulative sum (CUSUM) analysis was applied to visualize the learning curve on the adjusted volume reduction rate (VRR).

RESULTS

A total of 102 nodules in 93 patients were included in the analysis. Linear regression revealed that nodule composition was the main predictor of the VRR. The composition-adjusted VRR increased with the chronological treatment order. The series was divided into three phases based on inflection points of the CUSUM analysis: the initial learning phase (case 1-20), consolidation phase (case 21-65), and proficiency phase (case 66-102). In the later phase, more solid nodules were treated, power output used by the operator was higher, and RFA treatment time was longer.

CONCLUSION

The treatment efficiency of thyroid RFA was associated with technical proficiency, suggesting the presence of a learning curve effect.

Preoperative Factors Associated with Extrathyroidal Extension in Papillary Thyroid Cancer

OBJECTIVE

Extrathyroidal extension may not be accurately recognized during thyroidectomy and can increase the risk of positive margins and even recurrence. This study aimed to investigate the preoperative factors associated with extrathyroidal extension.

METHODS

We analyzed 887 patients with papillary thyroid cancer (PTC) who underwent surgery in the period of 2005-2017. Binary logistic regression analyses and generalized additive models were used to identify associations.

RESULTS

Minimal extrathyroidal extension was present in 233 (26%) patients and advanced extrathyroidal extension was found in 60 (7%) patients. Age, BMI, and tumor size were independent predictors of all or advanced extrathyroidal extension. Among the 493 patients whose BRAF mutation status was available, age (OR = 1.025), BMI (OR = 1.091), tumor size (OR = 1.544), and BRAF V600E mutation (OR = 2.311) were independently associated with extrathyroidal extension.

CONCLUSIONS

Older age, a greater BMI, a larger tumor size, and presence of the BRAF mutation were predictive of extrathyroidal extension. These factors should be taken into consideration in decision-making before surgery is performed.

Lymphovascular invasion of papillary thyroid carcinoma revisited in the era of active surveillance

INTRODUCTION

Lymphovascular invasion (LVI) is associated with disease recurrence and compromised survival in patients with thyroid cancer. Nonetheless, LVI is not identifiable on preoperative ultrasound or cytologic assessment. We aimed to explore the clinicopathological features associated with LVI.

PATIENTS AND METHODS

We conducted a retrospective review of our prospectively maintained database from 2009 to 2018. Multivariate analyses were performed to determine the associations between clinicopathological parameters and LVI. Generalized additive models were used to examine the nonlinear relationship between continuous variables and LVI.

RESULTS

A total of 795 patients were included in the analysis, and 174 (22%) had LVI. Patients' age (odds ratio [OR] = 0.982), tumor size (OR = 1.466), clinical lymphadenopathy (OR = 6.975), and advanced extrathyroidal extension (OR = 2.938) were independently associated with LVI. In the subset analysis of 198 patients with available genetic information, tumor size (OR = 1.599), clinical lymph node metastasis (OR = 3.657), and TERT promoter mutation (OR = 4.726) were predictive of LVI. Among 573 patients who had no clinical lymphadenopathy or advanced extrathyroidal extension, tumor size was the only predictor of LVI. Tumor size >1.5 cm had an increased risk of LVI based on the generalized additive model plot and receiver operating characteristic curve analysis.

CONCLUSION

Tumor size is positively associated with the risk of LVI in papillary thyroid cancer. To avoid delayed treatment in patients with LVI, a tumor size of 1.5 cm may be considered as the safe upper limit for active surveillance.

On the Image Sensor Processing for Lane Detection and Control in Vehicle Lane Keeping Systems

Lane keeping systems for a keeping a vehicle in the desired lane is key to advanced driving assistance system in autonomous vehicles. This paper presents a cost-effective image sensor with efficient processing algorithm for lane detection and lane control applications to autonomous delivery systems. The algorithm includes (1) lane detection by inverse perspective mapping and random sample consensus parabola fitting and (2) lane control by pure pursuit steering controller and classical proportional integral speed controller based on a nonholonomic kinematic model. The image sensor experiments conducted on a 1/10 scale model car maneuvering in a straight⁻curve⁻straight lane validate the better processing performance before, during, and after the turning section over previous work. The image sensor with the processing algorithm achieves the average lane detection error within 5% and maximum cross-track error within 9% in real-time. The development shall pave the way to cost-effective autonomous delivery systems.

Effects of Preoperative Iodine Administration on Thyroidectomy for Hyperthyroidism: A Systematic Review and Meta-analysis

OBJECTIVE

The current guidelines recommend that potassium iodide be given in the immediate preoperative period for patients with Graves' disease who are undergoing thyroidectomy. Nonetheless, the evidence behind this recommendation is tenuous. The purpose of this study is to clarify the benefits of preoperative iodine administration from published comparative studies.

DATA SOURCES

We searched PubMed, Embase, Cochrane, and CINAHL from 1980 to June 2018.

REVIEW METHODS

Studies were included that compared preoperative iodine administration and no premedication before thyroidectomy. For the meta-analysis, studies were pooled with the random-effects model.

RESULTS

A total of 510 patients were divided into the iodine (n = 223) and control (n = 287) groups from 9 selected studies. Preoperative iodine administration was significantly associated with decreased thyroid vascularity and intraoperative blood loss. Significant heterogeneity was present among studies. We found no significant difference in thyroid volume or operative time. Furthermore, the meta-analysis showed no difference in the risk of postoperative complications, including vocal cord palsy, hypoparathyroidism/hypocalcemia, and hemorrhage or hematoma after thyroidectomy.

CONCLUSION

Preoperative iodine administration decreases thyroid vascularity and intraoperative blood loss. Nonetheless, it does not translate to more clinically meaningful differences in terms of operative time and postoperative complications.

Removal of sulfonamides from wastewater in the UV/TiO2 system: effects of pH and salinity on photodegradation and mineralization

The effects of salinity on the photodegradation and mineralization of sulfonamides in the UV/TiO₂ system were investigated. The goals of this study were to analyze the effects of pH and salinity on the sulfonamide concentration and total organic carbon (TOC) during the removal of sulfonamides in a UV/TiO₂ system. Four sulfonamides - sulfadiazine (SDZ), sulfamethizole (SFZ), sulfamethoxazole (SMX) and sulfathiazole (STZ) - were selected as parent compounds. The photodegradation and mineralization rates of sulfonamides in the UV/TiO₂ system satisfy pseudo-first-order kinetics. Direct photolysis degraded sulfonamides but sulfonamides cannot be mineralized. The photodegradation and mineralization rate constants in all experiments followed the order pH 5 > pH 7 > pH 9. At pH 5, the mineralization rate constants of SMX, SFZ, SDZ and STZ were 0.015, 0.009, 0.012 and 0.011 min^-1, respectively. The addition of NaCl inhibited the mineralization of the four tested sulfonamides more than it inhibited their photodegradation. The inhibitory effect of chloride ions on the removal of sulfonamides in the UV/TiO₂ system was attributed to the scavenging by chloride ions of hydroxyl radicals (HO•) and holes and the much lower reactivity of chlorine radicals thus formed, even though the chlorine radicals were more abundant than HO•.

Preparation of immobilized Cu2O using microwave irradiation and its catalytic activity for bisphenol A: comparisons of Cu2O/H2O2 and visible-light/Cu2O/H2O2 systems

This study produced immobilized Cu2O via microwave irradiation. The surface properties of Cu2O were assessed by X-ray diffraction, scanning electron microscopy, and UV-vis spectroscopy. The catalytic activity of the generated Cu2O was examined for bisphenol (BPA) degradation in Cu2O/H2O2 and visible-light/Cu2O/H2O2 systems under various H2O2 concentrations. Cu2O can decompose H2O2 to generate radicals, similar to the Fenton-like process. The BPA degradation rate followed pseudo-first-order kinetics. The optimal H2O2 concentration was 30 mM and the BPA degradation rate under 30 mM H2O2 in the Cu2O/H2O2 and visible-light/Cu2O/H2O2 systems was 1.43 and 2.69 h(-1), respectively. The original Cu2O partly oxidized into CuO in the visible-light/Cu2O/H2O2 system and the BPA degradation percentage declined to 51% from 100% after the fifth cycle.

Orthorhombic BiFeO3

A new orthorhombic phase of the multiferroic BiFeO3 has been created via strain engineering by growing it on a NdScO(3)(110)(o) substrate. The tensile-strained orthorhombic BiFeO3 phase is ferroelectric and antiferromagnetic at room temperature. A combination of nonlinear optical second harmonic generation and piezoresponse force microscopy revealed that the ferroelectric polarization in the orthorhombic phase is along the in-plane {110}(pc) directions. In addition, the corresponding rotation of the antiferromagnetic axis in this new phase was observed using x-ray linear dichroism.

Effects of oxidant concentration and temperature on decolorization of azo dye: comparisons of UV/Fenton and UV/Fenton-like systems

This study applies photo-Fenton and photo-Fenton-like systems to decolorize C.I. Reactive Red 2 (RR2). The oxidants were H(2)O(2) and Na(2)S(2)O(8); Fe(2+), Fe(3+), and Co(2+) were used to activate these two oxidants. The effects of oxidant concentration (0.3-2 mmol/L) and temperature (25-55 °C) on decolorization efficiency of the photo-Fenton and photo-Fenton-like systems were determined. The decolorization rate constants (k) of RR2 in the tested systems are consistent with pseudo-first-order kinetics. The rate constant increased as oxidant concentration and temperature increased. Activation energies of RR2 decolorization in the UV/H(2)O(2)/Fe(2+), UV/H(2)O(2)/Fe(3+), UV/Na(2)S(2)O(8)/Fe(2+) and UV/Na(2)S(2)O(8)/Fe(3+) systems were 32.20, 39.54, 35.54, and 51.75 kJ/mol, respectively.

Removal of C.I. Reactive Red 2 from aqueous solutions by chitin: an insight into kinetics, equilibrium, and thermodynamics

In this study, C.I. Reactive Red 2 (RR2) was removed from aqueous solutions by chitin. Exactly how the RR2 concentration, chitin dosage, pH, and temperature affected adsorption of RR2 by chitin was then determined. After reaction for 120 min, the amount of 10 and 20 mg/L RR2 absorbed onto chitin was 5.7 and 7.5 mg/g, respectively. The adsorption percentage increased from 56 to 94% when the chitin dosage was increased from 1.5 to 2.5 g/L. Experimental results indicated that the pseudo-second-order model best represents adsorption kinetics. Adsorption of RR2 increased as the temperature increased; however, it decreased with an increased pH. Experimental results further demonstrated that the Freundlich model is superior to the Langmuir model in fitting experimental isotherms. The ΔH° and ΔS° were 16.34 kJ/mol and 152.10 J/mol K, respectively. ΔH° suggested that adsorption of RR2 onto chitin was via physisorption.

Microscopic origin of the giant ferroelectric polarization in tetragonal-like BiFeO(3)

We report direct experimental evidence for a room-temperature, ∼130  μC/cm(2) ferroelectric polarization from the tetragonal-like BiFeO(3) phase. The physical origin of this remarkable enhancement of ferroelectric polarization has been investigated by a combination of x-ray absorption spectroscopy, scanning transmission electron microscopy, and first principles calculations. A large strain-induced Fe-ion displacement relative to the oxygen octahedra, combined with the contribution of Bi 6s lone pair electrons, is the mechanism driving the large ferroelectric polarization in this tetragonal-like phase.

Effects of operational parameters on decolorisation of C.I. Reactive Black 5 in UV/TiO(2) system

This study utilises a UV/TiO(2) system to decolorise C.I. Reactive Black 5 (RB5). The effects of TiO(2) dosage, pH, RB5 concentration and light power on the decolorisation efficiency using the UV/TiO(2) system were determined. IO(4)(-) was employed as an oxidant to increase the photodegradation efficiency of UV/TiO(2). The decolorisation rate constants (k) of RB5 in the UV/TiO(2) system are consistent with pseudo-first-order kinetics. The k values of 0.1, 0.5, 1.0 and 2.0 g/l TiO(2) were 0.53, 0.52, 0.69 and 0.68 h(-1), respectively. The rate constant increases with decreasing pH from 10 to 4. The decolorisation rate approximates linear relationship with RB5 concentration, as given by k=1.05[1/RB5](0.98); it varies nonlinearly with light power, as given by k=0.178[power](0.63). The experimental results reveal that the rate of decolorisation obtained using UV/TiO(2)/IO(4)(-) exceeds that obtained using UV/TiO(2).

Caffeic acid phenethyl ester inhibits arterial smooth muscle cell proliferation and migration in vitro and in vivo using a local delivery system

Over the last two decades, significant advances have been made in percutaneous coronary intervention (PCI) for the treatment of atherosclerotic plaques. However, restenosis after PCI still challenges both vascular biologists and interventional cardiologists. In this study, we found that caffeic acid phenethyl ester (CAPE) displayed an inhibitory effect on human coronary smooth muscle cell (HCSMC) growth and migration. Flow cytometry analysis showed that the ratio of S phase increased after exposing cells to CAPE for 48-72 h. Pretreatment of cells with CAPE significantly suppressed Cyclin E, CDK2, Cyclin A, and proliferating-cell nuclear antibody expression. We demonstrated that CAPE inhibited AKT 1 and MEK1/2 activation. Using a local infusion system, CAPE was able to regress the intima thickening of the iliac artery in rabbits after balloon injury. The percentage of intimal thickening decreased significantly to 55.0 +/- 0.12 in the group after local CAPE infusion compared to the group after saline infusion (98.3 +/- 0.41%). In conclusion, CAPE can inhibit the proliferation and migration of HCSMCs by inducing cell cycle arrest. Decreased cell cycle genes and associated signaling pathway target gene expression may mediate anti-proliferative and anti-migration effects of CAPE. Furthermore, CAPE prevents intima thickening in rabbits after balloon angioplasty. These results indicate that CAPE may have therapeutic relevance for the prevention of restenosis during PCI in the treatment of coronary artery diseases.

Recovery of heavy metals from industrial sludge using various acid extraction approaches

Heavy metals were removed from industrial sludge by traditional and microwave-assisted acid extraction approaches. The effects of acid concentration, extraction time, sludge particle size and solid/liquid (S/L) ratio on copper-extraction efficiency were assessed. Leaching with increased acid concentrations increased the yield of heavy metals from the industrial sludge. In microwave-assisted acid extraction, reducing the S/L ratio and sludge particle size increased copper-extraction efficiency. These experimental findings indicate that S/L ratio most strongly influenced microwave-assisted acid extraction. Both traditional and microwave-assisted acid extraction demonstrate that sulfuric acid was an effective extractant, and the copper fraction in extracted sludge shifted from being primarily bound to Fe-Mn oxides and organic-matter partition, to being mostly bound to organic matter, remaining as a residue during acid extraction.

Computed tomography features of spontaneously perforated pyometra: a case report

Spontaneous perforation of pyometra is an extremely rare emergent gynecologic disease. We report a 73-year-old woman with a spontaneously perforated pyometra presenting with acute abdomen in the emergency department. A dedicated computed tomography examination of the abdominal and pelvic regions revealed the diagnosis. The patient recovered well after surgical intervention and antibiotic treatment.

Characteristics of aerosols collected in central Taiwan during an Asian dust event in spring 2000

Aerosol samples for PM(2.5) and PM(2.5-10) were collected at four locations in central Taiwan from 26 to 31 March 2000, a period that experienced exceedingly high PM levels from 29 to 30 March due to the passage of an Asian dust storm. The samples were analyzed for mass, metallic elements, ions, and carbon. The purpose of this paper is to investigate the influence of the dust storm on the characteristics of local ambient particulate matter. The results indicate that the concentrations of the crustal elements Ca, Mg, Al, Fe and the sea salt species Na+ and Cl- in PM(2.5-10) during the dust episode exceed the mean concentrations in the non-dust period by factors of 3.1, 2.9, 2.6, 2.2, 2.3 and 2.1 respectively. Enrichment factors of Ca, Fe, and Mg in PM(2.5-10) during the dust event are close to unity, indicating that these elements are from soil. Reconstruction of aerosol compositions revealed that soil of coarse particulates elevated approximately 50% in the dust event. It is noted that during the dust event, the ratio of Mg/Al in PM(2.5-10) ranged from 0.21 to 0.25 while that of Ca/Al ranged from 0.6 to 0.9, levels more constant than those obtained in non-dust period.

Hypercalcaemia and haemophagocytic syndrome: rare concurrent presentations of disseminated tuberculosis in a dialysis patient

Tuberculosis remains an important cause of infection in chronic haemodialysis patients. Frequent extrapulmonary involvement, non-specific presentation and limited diagnostic tools usually make early diagnosis difficult. Herein, we report on an 83-year-old female patient who had been on regular heamodialysis therapy for 15 years, who presented with asymptomatic hypercalcaemia and pancytopenia. Haemophagocytic syndrome was documented during the admission period. Mycobacterium tuberculosis was cultured from bone marrow 1 month after her demise. This case report highlights the non-specific manifestations of extrapulmonary tuberculosis in dialysis patients and the limited value of conventional diagnostic methods. We would like to recommend aggressive intervention and early tissue aspiration from possible infectious sites when tuberculosis cannot be completely ruled out. Disseminated tuberculosis should be considered as an indication of hypercalcaemia where haemophagocytic syndrome occurs simultaneously.

Study of human exposure to particulate PAHs using personal air samplers

Three common sources of environmental exposure to particulate polycyclic aromatic hydrocarbons (PAHs) in Taiwan were chosen for this study. They are smoke of incense burning, exhausts of motor vehicles, and fumes of charcoal burning. The campus environment without any specific PAH sources (nonpoint sources) was chosen as the control. The particulate PAH concentrations in the air samples containing smoke of incense burning were only slightly higher than those in the control. However, the total concentration of particulate PAHs in the air samples with exhausts of motor vehicles and fumes of charcoal burning was about 7.5 times and 22 times higher than those observed in the control, respectively. The mean inhalation amounts of particulate PAHs per unit time are very high both in samples with exhausts of motor vehicles (13.9 ng/min) and fumes of charcoal burning (38.1 ng/min). The exposure dose of 22 PAHs per day ranged from 3.18 to 18.0 microg/day under four exposure conditions. Moreover, the personal inhalation BaP(eq) levels are in the range of 0.4 to 1.55 microg/day.

Stabilization of human standing posture using functional neuromuscular stimulation

Functional neuromuscular stimulation (FNS)/functional electrical stimulation (FES) is a potential way to restore some functionality to the limbs of patients with spinal cord injury through direct/indirect stimulation of the motoneuron. One of the constraints for wider use of FNS on paraplegic patients is the lack of efficient control algorithm. Most of the published works on FNS/FES control are based on oversimplified models of human body dynamics. An innovative control strategy for stabilizing the standing posture of paraplegic patients is proposed here which is a combination of a proportional-plus-derivative controller for motions of the skeletal system and a control action prediction mechanism to produce musculotendon activation. The goal is to produce musculotendon torque which can approximate those demanded by the controller for the skeletal system. In computer simulations, using a detailed skeletal-musculotendon-muscle activation dynamics model of human body, this FNS/FES control approach can stabilize a paraplegic patient's standing posture with the minimum number of musculotendon groups. Also, it is found that this control strategy can maintain stability even in the presence of reasonable variations in the controller's musculotendon parameters.

Fluconazole therapy in neonatal candidemia

We reviewed 62 episodes (from 59 infants) of neonatal candidemia that occurred between January 1994 and June 1999. Except 5 term babies, all infants were premature (median gestational age [GA], 30 weeks) and birth weight was less than 2,500 g (median, 1,300 g). Most infants had reported risk factors and other neonatal problems. The age at onset of candidemia ranged from 15 to 173 days with a median of 34 days. In addition to catheter removal, all but one infants received antifungal agents and candidemia was eradicated subsequently in 46 episodes (75%). Eighteen infants with 19 episodes ever received fluconazole therapy. Fluconazole was administered as the first line agent in 6 episodes and successfully cleared candidemia in 5 episodes. Fluconazole was used as an alternative agent in an additional 13 episodes after amphotericin B (am B) +/- flucytosine were given for a period without a satisfactory result and eradication of candidemia was achieved in 8 episodes subsequently. All 18 infants tolerated fluconazole well and no withdrawal was required on account of its adverse effect. In contrast, am B alone was administered as the first line agent in 55 episodes and successfully cleared candidemia in 32 episodes (58%). This retrospective analysis suggests that fluconazole appears to be safe in neonates and can be used as an alternative agent in treating neonatal candidemia. A large-scaled prospective study may be needed.

Endothelin-A receptor antagonist prevents neonatal pulmonary hypertension in meconium aspiration in piglets

In order to test the hypothesis that endothelin-1 (ET-1) directly contributes to the pathophysiology of pulmonary hypertension induced by meconium aspiration, we randomized 12 anesthetized and paralyzed piglets to receive BQ-123, a selective endothelin-A receptor antagonist (BQ group), or normal saline (NS group) after meconium aspiration. The animals were instilled with meconium mixture (3 mL/kg) via an endotracheal tube, and then given intravenous BQ-123 (2 mg/hr) or normal saline. Plasma ET-1 concentrations, arterial blood gases, and hemodynamics were measured at baseline and at 60, 120, 180, and 240 minutes after instillation. The results showed that plasma ET-1 concentrations were similar in both groups. However, in the BQ group, pulmonary artery pressure was significantly lower after 120 minutes (p < 0.05 at 120 min, p < 0.01 at 180 and 240 min) and pulmonary vascular resistance was significantly lower after 180 minutes (p < 0.01) than in the NS group. No significant difference was found in systemic hemodynamics. These data suggest that ET-1 directly contributes to the pathophysiology of pulmonary hypertension induced by meconium aspiration.

Study of plasma endothelin-1 concentrations in Taiwanese neonates with respiratory distress

BACKGROUND

Endothelin-1 (ET-1) is a novel and potent endothelium-derived vasoconstriction peptide present in human plasma. In this study, plasma ET-1 concentrations were determined and their physiological significance was evaluated in Taiwanese neonates with respiratory distress.

METHODS

Sixty newborn infants consisting of 22 with respiratory distress syndrome (RDS), 13 with transient tachypnea of newborn (TTNB), 4 with meconium aspiration syndrome, 10 healthy preterm and 11 healthy full-term infants were included for plasma ET-1 determination. Plasma ET-1 levels were measured by enzyme immunoassay at the of age of 1 day. For those who were diagnosed with RDS, plasma ET-1 concentrations were scheduled for evaluation at the ages of 1, 2, 3, 7, 14, 28, and 35 days as long as oxygen was being used.

RESULTS

On the first day of life, there was no significant difference in plasma ET-1 concentrations between healthy preterm and term infants (3.92 +/- 0.88 vs. 3.56 +/- 1.98 pg/mL, p = 0.606). However, plasma ET-1 concentrations of infants with RDS were significantly higher than those with TTNB (6.46 +/- 0.58 vs. 3.77 +/- 1.29 pg/mL, p < 0.001). In RDS infants, plasma ET-1 concentrations showed no significant difference between those who developed bronchopulmonary dysplasia (BPD, N = 4) and those who recovered (non-BPD, n = 18) (7.84 +/- 1.85 vs. 5.81 +/- 2.76 pg/mL, p = 0.242).

CONCLUSION

Plasma ET-1 concentrations were similar in preterm and term infants. ET-1 concentrations were higher in infants with RDS than in infants with TTNB, which suggests that plasma ET-1 levels can be useful in the differential diagnosis. However, the plasma ET-1 concentrations can not be a predictor for BPD.

Effect of hypocapnia in the first three days of life on the subsequent development of periventricular leukomalacia in premature infants

Several etiologies for causing periventricular leukomalacia (PVL) in preterm infants have been investigated worldwidely. The aim of this study is to investigate whether hypocapnia plays a role in the pathogenesis of the subsequent development of PVL. From Jan. 1997 to June 1998, 91 premature infants (mean gestational age 28.8 +/- 2.5 weeks and birth body weight 1169 +/- 385 g) born in Chung Gung Children's Hospital requiring mechanical ventilation in the first 72 hrs were enrolled in our study. Serial neuorosonogram were followed on day 1, 3, 7 and then at least every 2 to 3 weeks until discharge. These infants were divided into two groups defined as the PVL group and non-PVL group. Variables comprising perinatal data were analyzed and compared between these two groups to screen out possible risk factors related to the development of PVL. There was no difference noted. As for the effect of PaCO2, we found the infants with PVL to have mean lower PaCO2 during the first 72 hours of life. (P = 0.004). Logistic regression model revealed that the incidence for PVL increased significantly when mean PaCO2 is lowered to less than 25 mmHg. Hypocapnia during the first three days of life seems to be an important etiological factor associated with the development of periventricular leukomalacia. Therefore, the ventilatory strategy in the care of the premature neonates should not only provide adequate ventilation but also careful avoidance of hypocapnia.

Modeling Competitive Adsorption of Molybdate, Sulfate, and Selenate on gamma-Al(2)O(3) by the Triple-Layer Model

Competitive adsorption of molybdate, sulfate, and selenate onto gamma-Al(2)O(3) was investigated in the present study. Binary solute systems of MoO(2-)(4)+SO(2-)(4), MoO(2-)(4)+SeO(2-)(4), and SO(2-)(4)+SeO(2-)(4) and a ternary solute system of MoO(2-)(4)+SO(2-)(4)+SeO(2-)(4) were evaluated to determine their relative effects on competitive adsorption on the gamma-Al(2)O(3) surface. Anionic competitive adsorption efficiency was pH dependent. The higher the pH, the lower the efficiency of MoO(2-)(4) in preventing SO(2-)(4) and SeO(2-)(4) adsorption; similar results were found in SeO(2-)(4) depressing SO(2-)(4) adsorption. This research found that more sites are occupied in mixed anionic adsorbate systems than when either ion is present alone. The results suggest that the gamma-Al(2)O(3) surface is composed of many groups of binding sites. Because of the heterogeneity of adsorption sites, the triple-layer model (TLM) predicted the competitive effects qualitatively but not quantitatively. TLM gave reasonable descriptions of molybdate adsorption in the presence of sulfate and selenate, indicating that the model may be useful in predicting molybdate adsorption on gamma-Al(2)O(3). Copyright 2001 Academic Press.

Effect of carbon dioxide tension in the first three days of life on the development of retinopathy of prematurity

BACKGROUND

This study focuses on the effect of carbon dioxide tension in the first 3 days of life on the development of retinopathy of prematurity (ROP) in mechanically ventilated premature infants.

METHODS

From January 1997 to June 1998, 91 premature infants (gestational age 28.8 +/- 2.5 weeks, birth weight 1169 +/- 385 g) born in Chung Gung Children's Hospital requiring mechanical ventilation in the first 72 hours were enrolled in our study. Ophthalmic examination was performed initially at 4-6 weeks of age and then every week if ROP was found and every other week if the result was normal until discharge. These infants were divided into 2 groups: those with and without ROP. Medical records of the highest and lowest blood gas measurements were recorded during the first 3 days of life. To screen for possible risk factors related to the development of ROP within these 2 groups, variables comprising perinatal data were compared.

RESULTS

The perinatal factors were compared, whish showed that infants with ROP had a lower mean gestational age (p < 0.001), mean birth body weight (p < 0.001), and a longer duration under mechanical ventilation (p < 0.001). The severity and incidence of ROP were not affected by either hypercapnia or hypocapnia; even with the superimposed effect of hyperoxia, the effect was minimal.

CONCLUSION

Hypercarbia or hypocarbia in the first 3 days of mechanically ventilated preterm neonates does not affect the subsequent development of retinopathy of prematurity. However, a lower gestational age and birth weight as well as longer-duration mechanical ventilation might be independent predictors for the occurrence of ROP. The role of PaCO2 in the pathophysiology of retinopathy of prematurity remains undetermined, and further investigation in the future is warranted.

Treatment and outcome of congenital diaphragmatic hernia

BACKGROUND AND PURPOSE

Congenital diaphragmatic hernia (CDH) is a challenging condition and is associated with a high mortality rate; optimal therapy remains unclear. This retrospective study describes the clinical characteristics of treatment and outcome in 48 infants with CDH.

METHODS

Twenty-eight male (58%) and 20 female (42%) infants with CDH were treated from 1987 through 1998. The goals of the ventilator strategy were permissive hypercapnea (PaCO2 < or = 55 mm Hg) and avoidance of hyperventilation. Infants were initially ventilated with an intermittent mandatory rate of 40 to 60 per minute, peak inspiratory pressure of 20 to 25 cm H2O, and positive end-expiratory pressure of 5 cm H2O. High-frequency positive pressure ventilation was used if hypoxemia or severe hypercapnea (PaCO2 > 60 mm Hg) occurred. Most infants underwent repair after 3 days of age and only four infants underwent early repair within 24 hours of birth. A prophylactic chest tube was placed in the ipsilateral hemithorax postoperatively in all patients treated before 1996. The severity of respiratory distress was estimated by alveolar-arterial oxygen difference, oxygenation index, and alveolar-arterial ratio.

RESULTS

Forty-six patients presented with Bochdalek CDH, and two with Morgangni CDH. Antenatal diagnosis was made in 10 cases. Respiratory distress was the major manifestation and usually occurred immediately after birth. Six cases were diagnosed several months after birth and presented mainly with gastrointestinal symptoms. Eleven patients died before surgery and 37 patients underwent surgical repair. Two infants died postoperatively because of congestive heart failure and tension pneumothorax, respectively. The overall mortality rate was 27%. The major causes of mortality were severe respiratory failure, persistent pulmonary hypertension, pneumothorax, and associated anomalies.

CONCLUSION

Nearly 75% of patients in this series survived. This suggests that noninvasive respiratory care combined with delayed surgery may be an acceptable strategy for the treatment of CDH, and can be used in most medical institutions without equipment for extracorporeal membrane oxygenation therapy.

The effect of the Taiwan motorcycle helmet use law on head injuries

OBJECTIVES

This study evaluated the effect of the motorcycle helmet law implemented in Taiwan on June 1, 1997.

METHODS

Collecting data on 8795 cases of motorcycle-related head injuries from 56 major Taiwanese hospitals, we compared the situation 1 year before and after implementation of the helmet law.

RESULTS

After implementation of the law, the number of motorcycle-related head injuries decreased by 33%, from 5260 to 3535. Decreases in length of hospital stay and in severity of injury and better outcome were also seen. The likelihood ratio chi 2 test showed that severity decreased after the law's implementation (P < .001). Full helmets were found to be safer than half-shell helmets.

CONCLUSION

The helmet law effectively decreased the mortality and morbidity from motorcycle-related head injuries.

Candidaemia in special care nurseries: comparison of albicans and parapsilosis infection

OBJECTIVES

Candidaemia caused by Candida parapsilosis (CP) is being increasingly reported among infants in neonatal intensive care units (NICU). To assess relative severity, clinical manifestations of candidaemia caused by C. albicans (CA) and CP in a NICU were compared.

METHODS

Between January 1994 and July 1997, episodes of candidaemia occurring among infants hospitalized in the NICU were identified in a children's hospital. The demographic characteristics, associated risk factors, clinical manifestations and outcome of the infants with CP fungaemia were collected and compared with those of the infants with CA fungaemia.

RESULTS

Twenty-four episodes caused by CA and 22 episodes caused by CP were included in this study. No significant differences were found between the two groups for gestational age, birth weight, male gender, post-natal age at onset of candidaemia, frequency of antecedent neonatal events, prior duration of antibiotic therapy and hyperalimentation, as well as presence of central venous catheter (CVC). Infants with CA fungaemia were significantly more likely than those with CP fungaemia to present with hypoxaemia, bradycardia and respiratory distress requiring intubation, and have a longer prior duration of indwelling CVC and a higher dissemination rate. The eradication rate of candidaemia and overall case fatality rate were comparable in both groups. but CP fungaemia did not appear to cause acute lethal events.

CONCLUSION

The presenting signs of CP fungaemia are relatively not so severe, but CP fungaemia, which is relatively difficult to eradicate, increases the morbidity and mortality of the infants.

Idiopathic myelofibrosis associated with renal extramedullary hematopoiesis and nephrotic syndrome: case report

Idiopathic myelofibrosis is characterized by bone marrow fibrosis, anemia, leukoerythroblastosis, and extramedullary hematopoiesis in many organs. Renal abnormalities in idiopathic myelofibrosis have been rarely described in the literature and include extramedullary hematopoiesis in the pararenal or retroperitoneal areas resulting in obstructive uropathy and hemtopoietic cell infiltration in tubulointerstitial area and urolithiasis. These lead to azotemia or acute renal failure, which may respond well to radiotherapy and adjuvant chemotherapy. To our knowledge, there has been only one case report of nephrotic syndrome associated with glomerulonephritis in a myelofibrosis patient; however, no effective treatment was described. Herein, we report the case of a patient with idiopathic myelofibrosis who initially presented with hepatomegaly, anemia, and leukoerythroblastosis. A nephrotic syndrome developed 7 years after initial diagnosis. Renal biopsy disclosed the unique pathological finding of simultaneous mesangial proliferative glomerulonephritis, renal extramedullary hematopoiesis, and gouty nephropathy. Despite treatment with busulfan, proteinuria persisted that implied irreversible glomerular injury and a terminal prognosis. We focus on the unusual pathological finding and the association between nephrotic syndrome and idiopathic myelofibrosis.

Multiple myeloma presenting with a paraspinal tumor and malignant effusion: case report

We describe a patient with multiple myeloma which presented as a thoracic paraspinal tumor and myelomatous pleural effusion. He had manifested a gradual onset of upper back pain with radiation to the left chest wall for 3 months. A radiographic examination showed left pleural effusion and a paraspinal tumor with rib destruction at the--left T5-6 level. Laboratory data showed anemia and a reversed serum albumin to globulin ratio. Protein electrophoresis and immunoelectrophoresis showed a monoclonal IgG-lambda chain component in the serum, urine, and pleural effusion fluid. Ultrasound-guided transthoracic mass biopsy and thoracentesis were performed for diagnosis. Biopsy of the thoracic tumor showed a solid mass composed of immature plasma cells. The pleural effusion fluid contained numerous immature plasma cells. An immunophenotype study of the pleural effusion fluid revealed monoclonal plasma cells, compatible with malignant pleural effusion. A specimen of bone marrow was interpreted as typical for plasma cell myeloma. Local radiotherapy and chemotherapy with melphalan and prednisolone resulted in good partial remission with a stable condition. Later, however, the disease flared up and hyperviscosity syndrome developed with epistaxis and retinal hemorrhage. He died of sepsis about 15 months after the initial diagnosis.

Bone marrow examinations as final clue to diagnosis of hypercalcemia: report of two cases

Two young men with severe hypercalcemia in association with renal failure (one acute and one chronic) are reported in whom usual diagnostic tests failed to reveal an etiology, and the final diagnoses were given by bone marrow examinations. Early bone marrow examinations in specific patients with hypercalcemia of undetermined origin sometimes are vital as shown by our two patients.

Correlation between the amounts of polycyclic aromatic hydrocarbons and mutagenicity of airborne particulate samples from Taichung City, Taiwan

Taichung is the largest city in the central part of Taiwan, and its air pollution problems are similar to those in other large cities around the world. To evaluate the potential of the air pollution and identify major pollutant sources in this city, 181 airborne particulate samples were collected biweekly from seven locations around Taichung over an entire year. The mutagenicity of acetone extracts of the air samples was evaluated using the Salmonella/microsomal test with Salmonella typhimurium TA98 in the presence and absence of S9 mixtures. The air samples from September 1994 showed the highest direct and indirect mutagenicity among the 12 months, whereas those from October and June had the lowest direct and indirect mutagenicity, respectively. To elucidate the correlation between mutagenicity and polycyclic aromatic hydrocarbons (PAHs), high-performance liquid chromatography was used to determine the amount of each of 10 PAHs in the air samples. Among the 10 PAHs, the monthly average amount of B[g,h,i]P in the samples was the highest, followed by B[a]FA, B[a]P, and B[k]FA. Linear regression analysis showed a positive correlation between monthly average total amounts of PAHs and indirect mutagenicity. The monthly average amount of B[g,h,i]P was correlated more with indirect mutagenicity than with other PAHs. B[g,h,i]P is an indicator PAH emitted from both diesel and gasoline engine exhaust. Thus, we suggest that mobile air pollutant sources in Taichung City may be more significant than stationary ones. Moreover, B[g,h,i]P seems to act as a mutagenicity indicator compound in air samples from Taichung City.

Liquid ventilation for treatment of meconium aspiration syndrome in a piglet model

We tested the hypothesis that liquid ventilation (LV) with perfluorocarbon (PFC) can remove aspirated meconium and improve lung function in experimental meconium aspiration syndrome (MAS). PFC (FC-77) was used as the medium in LV. Sixteen piglets were divided into control and LV groups (8 animals/group). All animals received slurry meconium (20% in normal saline) via endotracheal instillation at baseline. Thirty minutes later, the LV group received 15 cycles of LV. Pulmonary mechanics, arterial blood gases, and hemodynamic values were recorded at baseline, and 30, 60, 120, 180, and 240 minutes after meconium instillation. Chest radiographs and lung sections were taken and scored at the end of the study. The percentage of meconium cleared by LV was calculated as the ratio of the dry weight of washings to that of meconium instilled, multiplied by 100. The procedure was tolerated well by the animals. LV cleared 25% +/- 7% of the instilled meconium. Tidal volume (9.5 +/- 2.0 vs 7.1 +/- 0.8 mL/kg, p = 0.012), respiratory system compliance (2.32 +/- 0.60 vs 1.60 +/- 0.24 mL/cmH2O, p = 0.01), PaO2 (65 +/- 7 torr vs 55 +/- 6 torr, p = 0.0067), and arterial to alveolar oxygen ratio (0.14 +/- 0.01 vs 0.12 +/- 0.01, p = 0.0077) were improved in the LV group at 60 minutes after meconium instillation compared with those of the control group. The scores of exudative debris (1.7 +/- 0.3 vs 2.1 +/- 0.2) and visible meconium (1.4 +/- 0.5 vs 2.1 +/- 0.5) were significantly lower in the LV group. In conclusion, short-term L.V with FC-77 can partially remove aspirated meconium from the lungs and improve pulmonary function transiently.

Improved application of ion chromatographic determination of carboxylic acids in ozonated drinking water

A direct ion chromatographic method of measuring carboxylic acids was modified and expanded to include measurement of eight components at parts-per-billion levels. These components, listed by eluting order, were acetate, propionate, formate, pyruvate, glyoxalate, dichloroacetate, oxalate and ketomalonate. The calculated method detection limits were 2-6 micrograms/l. Preliminary data were obtained by using California state project water from the filter influent of the Oxidation Demonstration Plant of the Metropolitan Water District of Southern California. Oxalate was measured at levels above 200 micrograms/l, formate above 100 micrograms/l, acetate above 50 micrograms/l, pyruvate and glyoxalate at approximately 30 micrograms/l and propionate and ketomalonate at trace levels near the detection limits. This method utilizes a new preservative, benzalkonium chloride, as a substitute for the environmentally unsafe mercuric chloride that had previously been used. Preservation studies indicate that all eight compounds are stable for a testing period of 30 days when benzalkonium chloride is maintained at or above 30 mg/l in the water sample.

A nationwide epidemiological study of spinal cord injury in geriatric patients in Taiwan

This prospective epidemiological survey of spinal cord injury (SCI) in Taiwan was carried out among patients attended by physicians from various medical centers and general hospitals all over Taiwan from July 1992 to June 1996. In all, 1,586 new cases of SCI were registered, representing about 70% of all possible SCI cases in Taiwan. The observed average annual incidence of SCI in Taiwan was 18.8 per million people, whereas it was 47.5 for the geriatric section. The mean age was 46.1 years with a plateau distribution after 20 years and older. Geriatric victims (297 cases, 18.7%, group II) formed a major section of SCI cases in Taiwan. Another group of younger SCI patients (15-64 years old, 1,232 cases, group I) was selected for comparison. The results showed that the male-to-female ratio, pattern of neurological deficits, and causes of injury and death of geriatric SCI patients differed significantly from those of the younger SCI group. Elderly women were exposed to a higher risk of SCI than younger women (M/F ratio 1.7:1). Falls were the leading cause of geriatric SCI, and two thirds of them occurred on level ground. Traffic accidents accounted for a third of SCI cases, half of which involved motorcycle accidents, a fifth of them pedestrians. Quadriplegia and quadriparesis occurred more frequently among elderly cases of SCI than in the younger group and a higher proportion of them died of SCI complications. Two thirds of elderly SCI patients recovered well enough after comprehensive treatment to be able to take care of themselves at home. The government should initiate programs of prevention to reduce the prevalence of geriatric SCI in Taiwan.

Stimulated human leukocytes cause activating mutations in the K-ras protooncogene

Human tissues which are chronically infiltrated with inflammatory leukocytes are more likely to develop malignancies than non-inflamed tissues, however the mechanism(s) by which leukocytes contribute to carcinogenesis is unknown. Stimulated human leukocytes release superoxide anion and hydrogen peroxide which, in the presence of iron, can be converted into the potent oxidant, hydroxyl radical (.OH). Previous studies have shown that leukocyte-derived .OH (or a .OH-like species) can cause DNA damage, however a relationship between leukocyte-induced DNA damage and carcinogenesis has not been established. The present report demonstrates that leukocyte-derived .OH-induced DNA damage can cause K-ras oncogene activation, and suggests that there may be a characteristic pattern of .OH-induced K-ras oncogene activation. Since activation of the K-ras oncogene is believed to play a crucial role in the pathogenesis of many human malignancies, .OH-induced K-ras oncogene activation could be an important mechanism by which human leukocytes contribute to carcinogenesis.

Retinal function abnormalities in membranoproliferative glomerulonephritis type II

PURPOSE

To characterize retinal electrophysiologic and psychophysical abnormalities associated with membranoproliferative glomerulonephritis type II.

METHODS

Three adults with membranoproliferative glomerulonephritis type II were studied. Retinal function was measured psychophysically (automated perimetry, Farnsworth D-15 color vision testing, and dark adaptometry) and electrophysiologically (full-field flash electroretinography and electro-oculography).

RESULTS

Two symptomatic individuals had prominent drusenlike deposits and retinal pigment epithelial disturbances, findings characteristic of membranoproliferative glomerulonephritis type II retinopathy. These individuals had mild visual field and color vision abnormalities, prolonged dark adaptation, and delayed electroretinographic dark-adapted dim and bright flash responses of normal amplitude. The electro-oculogram of the most severely affected individual was abnormal. The third individual who was asymptomatic had the mildest fundus abnormalities and exhibited normal psychophysical and electrophysiologic responses.

CONCLUSIONS

Membranoproliferative glomerulonephritis type II retinopathy may be associated with symptomatic and measurable psychophysical and electrophysiologic abnormalities of retinal function.

Relief of protracted hypercarbia by high-frequency oscillatory ventilator in a young infant with bronchopulmonary dysplasia

Conventional ventilators have their limitations in management of certain conditions such as protracted hypercarbia in bronchopulmonary dysplasia (BPD). Although high-frequency ventilators (HFV) may be less effective in patients with lung diseases complicated by high airway resistance, such as BPD, high-frequency oscillatory ventilators (HFOV) can still provide an alternative treatment of choice due to its property of active exhalation, in addition to its tidal volume being less than dead space and its minute ventilation being more dependent on tidal volume. This report describes 3 episodes of successful relief of protracted hypercarbia in a young infant with BPD using HFOV after failure of conventional ventilatory therapy.

The effect of decoction of Artemisia, Rheum, and Gardeniae in a piglet model of hyperbilirubinemia

To find an alternative treatment for neonatal hyperbilirubinemia, the effect of a decoction of Artemisia Rheum Gardeniae was tested in an animal model. Fifteen male newborn piglets (four to six days old) were separated into three groups (five piglets/group). The animals of the first group, or Control Group, were intravenously infused with purified bilirubin (40 mg/kg) to simulate neonatal indirect hyperbilirubinemia. The animals of the second and the third groups received the decoction via oral-gastric tube feeding (Enteral Treatment Group) and intravenous injection (Parenteral Treatment Group), respectively, after infusion of bilirubin. Serum bilirubin levels were determined at 0, 0.5, 1, 2, 4 and 8 hours in these groups. The results revealed no significant effect of the decoction on hyperbilirubinemia within eight hours. The implication of this study suggests that a decoction of Artemisia Rheum Gardeniae may be not useful in the treatment of neonatal hyperbilirubinemia.

Effect of leak around the endotracheal tube on measurements of pulmonary compliance and resistance during mechanical ventilation: a lung model study

We studied the effect of leaks around the endotracheal tube (ETT) on the measurement of pulmonary mechanics during mechanical ventilation. We also evaluated the influence of different ventilator settings on the magnitude of leak. An adjustable leak was created at the end of the ETT in a lung model with constant compliance. Flow, tidal volume, and pressure changes were measured above and below the leak. Compliance (Ci) and resistance (Ri) during inspiration were determined by linear regression analysis (LRA) using the equation of motion and the Mead and Wittenberger method (MWM). The ventilatory change that influenced the degree of leak most was prolongation of inspiratory time (Ti). The presence of a leak around the ETT resulted in an overestimation of the Ci and Ri values, which was proportional to the size of the leak. This overestimation was also influenced by the method used to determine Ci and Ri. Because the contribution of the leak to the fidal volume progressively increases as inspiration continued, methods of analysis that depended mainly on measurement points at the end of inspiration showed a larger deviation from the true Ci and Ri values than methods mainly influenced by measurement points at the beginning of inspiration. Because of this, shortening of inspiration, or analysis of points at the beginning of inspiration reduces the error in the measurements of Ci and Ri when a leak is present. Breaths with a large leak should be excluded from any analysis of pulmonary mechanics.