Evaluation of porous membrane core elasticity and porous morphology for polypyrrole trilayer actuators

Multilayer electroactive polymer actuators consisting of polypyrrole films electropolymerized on a passive polymer membrane core have been harnessed as a source of simple actuation. As an integral component of the actuator, the membrane plays a vital role in the transport of ionic species and largely dictates the stiffness of the layered configuration, yet in past studies the specification of the membrane has remained largely arbitrary. In this investigation, we use quasi-static and dynamic mechanical analysis to investigate the impact of the mechanical properties of the membrane on the actuation response of polypyrrole-based trilayer bending actuators. Candidate materials with distinctly varied microcellular morphologies are identified and include polyvinylidene difluoride, nylon, and nitrocellulose. The quasi-static stress-strain response and the frequency-dependent viscoelastic nature of the candidates are then evaluated. On the basis of mechanical properties these results indicate that polyvinylidene difluoride membranes are superior to the other candidates for application as trilayer actuator cores. Bis(trifluoromethane)sulfonimide doped polypyrrole actuators with polyvinylidene difluoride cores and nylon cores are then fabricated under various synthesis conditions and their electromechanical actuation behavior is reported.

Smart sensor systems for human health breath monitoring applications

Breath analysis techniques offer a potential revolution in health care diagnostics, especially if these techniques can be brought into standard use in the clinic and at home. The advent of microsensors combined with smart sensor system technology enables a new generation of sensor systems with significantly enhanced capabilities and minimal size, weight and power consumption. This paper discusses the microsensor/smart sensor system approach and provides a summary of efforts to migrate this technology into human health breath monitoring applications. First, the basic capability of this approach to measure exhaled breath associated with exercise physiology is demonstrated. Building from this foundation, the development of a system for a portable asthma home health care system is described. A solid-state nitric oxide (NO) sensor for asthma monitoring has been identified, and efforts are underway to miniaturize this NO sensor technology and integrate it into a smart sensor system. It is concluded that base platform microsensor technology combined with smart sensor systems can address the needs of a range of breath monitoring applications and enable new capabilities for healthcare.

Respiration rate and swimming activity of larvae of two sub-tidal nassariid gastropods under reduced oxygen levels: implications for their distributions in Hong Kong waters

The effects of hypoxia on the larvae of two sub-tidal nassariid gastropods, Nassarius siquijorensis and N. conoidalis were compared so as to understand how the species-specific tolerance to hypoxia might have resulted in changes in the abundance and distribution of these two species in the hypoxic Tolo Harbour, Hong Kong, since the 1980s. Respiration rates of N. siquijorensis and N. conoidalis larvae were reduced at 4.5 mg O2 l(-1), or below, as compared with the normoxic control. Significant reduction in swimming velocity was also observed for 10-day old larvae which were exposed to <2.0 mg O2 l(-1) for N. siquijorensis and <1.0 mg O2 l(-1) for N. conoidalis. The 48 h LC50 values of N. siquijorensis and N. conoidalis larvae were 0.7 and 1.7 mg O2 l(-1), respectively. The results suggested that N. siquijorensis are more tolerant to hypoxia than N. conoidalis.

Painful laser stimuli induce directed functional interactions within and between the human amygdala and hippocampus

The pathways by which painful stimuli are signaled within the human medial temporal lobe are unknown. Rodent studies have shown that nociceptive inputs are transmitted from the brainstem or thalamus through one of two pathways to the central nucleus of the amygdala. The indirect pathway projects from the basal and lateral nuclei of the amygdala to the central nucleus, while the direct pathway projects directly to the central nucleus. We now test the hypothesis that the human ventral amygdala (putative basal and lateral nuclei) exerts a causal influence upon the dorsal amygdala (putative central nucleus), during the application of a painful laser stimulus. Local field potentials (LFPs) were recorded from depth electrode contacts implanted in the medial temporal lobe for the treatment of epilepsy, and causal influences were analyzed by Granger causality (GRC). This analysis indicates that the dorsal amygdala exerts a pre-stimulus causal influence upon the hippocampus, consistent with an attention-related response to the painful laser. Within the amygdala, the analysis indicates that the ventral contacts exert a causal influence upon dorsal contacts, consistent with the human (putative) indirect pathway. Potentials evoked by the laser (LEPs) were not recorded in the ventral nuclei, but were recorded at dorsal amygdala contacts which were not preferentially those receiving causal influences from the ventral contacts. Therefore, it seems likely that the putative indirect pathway is associated with causal influences from the ventral to the dorsal amygdala, and is distinct from the human (putative) indirect pathway which mediates LEPs in the dorsal amygdala.

Spatial attention to thermal pain stimuli in subjects with visual spatial hemi-neglect: extinction, mislocalization and misidentification of stimulus modality

One approach to the study of disordered spatial attention is to carry out tests of extinction, in which stimuli are detected on the left when they are presented on the left alone, but not when both sides are stimulated simultaneously in a dual simultaneous stimulation (DSS) protocol. Extinction has been documented for multiple sensory modalities, but not for thermal pain stimuli, to our knowledge. We now test the hypothesis that subjects with visual spatial neglect (hemi-neglect) will have alterations in thermal pain sensation which are related to abnormal spatial attention. The results demonstrate that thermal pain extinction of hot and cold pain stimuli occurs in a proportion of subjects with hemi-neglect. In the subjects with visual spatial hemi-neglect but without thermal pain extinction, the sensation of the thermal pain stimulus on the affected (left) side was not extinguished but was often localized to the unaffected (right) side, and the submodality of the stimulus (cold or hot) was often misidentified. Ratios indicating the magnitude of extinction, mislocalization and misidentification were significantly larger on the left side of subjects with visual spatial neglect than in healthy controls or in controls with stroke but without hemineglect. The proportion of subjects with thermal pain extinction, mislocalization, or misidentification was significantly higher in subjects with hemi-neglect than those in either control group. These results demonstrate that disordered attention exerts a powerful effect upon the perception of both the location and the quality of thermal pain stimuli.

Global DNA methylation, DNMT1, and MBD2 in patients with systemic lupus erythematosus

To investigate the associations of DNA methylation levels and mRNA expressions of DNA cytosine-5-methyltransferase 1 (DNMT1) and methyl CpG-binding domain 2 (MBD2) with systemic lupus erythematosus (SLE), 108 patients with SLE and 97 healthy controls were enrolled in this study. DNA and total RNA were extracted from the peripheral blood mononuclear cells of the SLE patients and the controls. The global methylation levels of DNA were measured in 63 patients with SLE and 68 healthy controls by the ELISA method. DNMT1 and MBD2 mRNA were also detected in 108 SLE patients and 97 controls using the quantitative real-time polymerase chain reaction method. The global methylation level of DNA was significantly decreased in the SLE patients in comparison with that in the controls ( p < 0.001, 95% CI = 0.1573–0.5052). The patients with SLE have higher expressions of DNMT1 and MBD2 mRNA than the controls ( p < 0.001, 95% CI = −0.0049 – −0.0019 and p = 0.001, 95% CI = −0.0119 – −0.0029, respectively). We also found that there were no significant differences in the methylation level and the expression of DNMT1 and MBD2 mRNA between the active and the inactive SLE patients. A positive correlation was also found between DNMT1 and MBD2 mRNA expressions in the SLE patients ( p < 0.001). This study demonstrated that the patients with SLE had a significantly lower level of DNA methylation than the controls. The expression of both DNMT1 and MBD2 mRNA was significantly increased in the SLE patients compared with the controls. This study also showed a positive correlation between DNMT1 and MBD2 mRNA levels in the patients with SLE.

Limited Multiplication of Symbiotic Cyanobacteria of Azolla spp. on Artificial Media

We examined various media and conditions to isolate symbiotic cyanobacteria from the leaf cavities of Azolla spp. Cyanobacteria survived and multiplied to a limited extent on a medium with fructose, Casamino Acids, yeast extract, and NaNO(3) under 1% O(2). These cyanobacteria were antigenically identical to the endosymbionts.

Understanding bamboo flowering based on large-scale analysis of expressed sequence tags

Unlike other plants, bamboo (Bambusoideae) flowering is an elusive physiological phenomena, because it is unpredictable, long-periodic, gregarious, and uncontrollable; also, bamboo plants usually die after flowering. The flowering mechanism in Arabidopsis thaliana, a eudicot model species, is well established, but it remains unknown in bamboo species. We found 4470 and 3878 expressed sequence tags in the flower bud and vegetative shoot cDNA libraries, respectively, of the bamboo species, Bambusa oldhamii. Different genes were found expressed in bamboo flower buds compared to vegetative shoots, based on the Munich Information Center for Protein Sequences functional categorization; flowering-related genes were also identified in this species. We also identified Arabidopsis flowering-specific homologs that are involved in its photoperiod in this bamboo species, along with autonomous, vernalization and gibberellin-dependent pathways, indicating that bamboos may have a similar mechanism to control floral transition. Some bamboo expressed sequence tags shared high similarity with those of rice, but others did not match any known sequences. Our data lead us to conclude that bamboo may have its own unique flowering genes. This information can help us understand bamboo flowering and provides useful experimental methods to study the mechanisms involved.

Suppressor of cytokine signaling 1 gene expression and polymorphisms in systemic lupus erythematosus

With the aim of investigating the role of suppressor of cytokine signaling 1 (SOCS1) in the pathogenesis of systemic lupus erythematosus, 107 patients with systemic lupus erythematosus, 101 healthy controls, and 151 patients with ankylosing spondylitis were enrolled in this study. SOCS1 mRNA level was measured by the method of quantitative real-time polymerase chain reaction. SOCS1 polymorphisms were detected by the polymerase chain reaction/restriction fragment length polymorphisms method. Systemic lupus erythematosus disease activity was evaluated with the SLEDAI. This study showed that the SOCS1 mRNA expression was significantly higher in the patients with systemic lupus erythematosus than in the healthy controls (p = 0.0014). Patients with active systemic lupus erythematosus had a higher expression of SOCS1 mRNA than the patients with inactive systemic lupus erythematosus (p = 0.035). There was no significant difference in the frequencies of the SOCS1-1478CA/del polymorphisms among the patients with systemic lupus erythematosus, healthy controls, and patients with ankylosing spondylitis. The genotype frequency of the SOCS1-1478 polymorphisms in the dominant model (CA/del+del/del versus CA/CA) was significantly decreased in the patients with thrombocytopenia compared with those without thrombocytopenia (p(c) = 0.035). Moreover, the allele frequency of SOCS1-1478del was also significantly lower in the patients with thrombocytopenia than in those without thrombocytopenia (p( c) = 0.02). In conclusion, this study demonstrated that the expression of SOCS1 mRNA was significantly increased in patients with systemic lupus erythematosus. Moreover, SOCS1 mRNA levels in patients with active systemic lupus erythematosus were significantly higher than those in the inactive patients. We also found that the systemic lupus erythematosus patients with thrombocytopenia have a lower frequency of SOCS1-1478del compared with patients without thrombocytopenia.

Painful stimuli evoke potentials recorded from the medial temporal lobe in humans

The role of human medial temporal structures in fear conditioning has led to the suggestion that neurons in these structures might respond to painful stimuli. We have now tested the hypothesis that recordings from these structures will demonstrate potentials related to the selective activation of cutaneous nociceptors by a painful laser stimulus (laser evoked potential, LEP) (Kenton B, Coger R, Crue B, Pinsky J, Friedman Y, Carmon A (1980) Neurosci Lett 17:301-306). Recordings were carried out through electrodes implanted bilaterally in these structures for the investigation of intractable epilepsy. Reproducible LEPs were commonly recorded both bilaterally and unilaterally, while LEPs were recorded at contacts on the left (9/14, P=0.257) as commonly as on the right (5/14), independent of the hand stimulated. Along electrodes traversing the amygdala the majority of LEPs were recorded from dorsal contacts near the central nucleus of the amygdala and the nucleus basalis. Stimulus evoked changes in theta activity were observed at contacts on the right at which isolated early negative LEPs (N2*) responses could be recorded. Contacts at which LEPs could be recorded were as commonly located in medial temporal structures with evidence of seizure activity as on those without. These results demonstrate the presence of pain-related inputs to the medial temporal lobe where they may be involved in associative learning to produce anxiety and disability related to painful stimuli.

Rapid dose-dependent effect of clozapine on a schizophrenic patient's lipid profile

Clozapine is known to be associated with higher risk of metabolic syndrome, including dyslipidaemia, but the mechanisms of such a relationship are still under debate. The case we reported shows a seemingly dose-dependent effect of clozapine on a patient's lipid profiles with no influence on his blood sugar in a relatively short period of time. A direct effect of clozapine on lipid metabolism, independent of insulin or obesity-related metabolic changes, is suggested. The rapid effect of clozapine on lipid profile allows fine-tuning in dose adjustment while treating refractory schizophrenia complicated with drug-related dyslipidaemia but worrying about psychotic rebound during clozapine discontinuation.

Antidepressant-associated mania: soon after switch from fluoxetine to mirtazapine in an elderly woman with mixed depressive features

Mirtazapine augmentation to a serotonin-reuptake inhibitor has been proposed to boost antidepressant effects and more likely to induce manic switch. Such a combined antidepressant therapy strategy should be used carefully if the patient's refractoriness is attributable to mixed depressive features. Mixed depression is more difficult to be treated by antidepressant monotherapy and related to higher risk of manic switch during treatment. We report a case with no previous history of bipolar disorder, whereas developed full-blown psychotic manic symptoms soon after switch from fluoxetine to mirtazapine. The patient's premorbid characters and clinical presentations suggested an implicit bipolarity that predisposed her to a manic switch. Her manic switch was likely to be triggered by a simulated combined effect because of complex drug interactions during shifting from fluoxetine to mirtazapine. For patients in mixed depressive states, mood stabilizers are preferable to antidepressants.

A painful cutaneous laser stimulus evokes responses from single neurons in the human thalamic principal somatic sensory nucleus ventral caudal (Vc)

Cutaneous application of painful radiant heat laser pulses evokes potentials (laser-evoked potentials) that can be recorded from scalp or intracranial electrodes. We have now tested the hypothesis that the response of thalamic neurons to a cutaneous laser stimulus occurs at latencies predicted by the conduction delay between the periphery and the thalamus. We have carried out recordings from human thalamic neurons in the principal sensory nucleus (ventral caudal) in patients undergoing awake surgery for the treatment of tremor. The results demonstrate that many neurons respond to the laser with early and/or late latency peaks of activity, consistent with conduction of the response to the laser stimulus through pathways from Adelta and C fibers to the thalamus. These peaks were of short duration, perhaps due to the somatotopic- and modality-specific arrangements of afferent pathways to the thalamus. The responses of these thalamic neurons to the laser stimulus sometimes included low-threshold spike (LTS) bursts of action potentials, consistent with previous studies of different painful stimuli. A prior study has demonstrated that spike trains characterized by common LTS bursts such as the intermediate (I) category spontaneously change their category more commonly than do those without LTS bursts (NG: nongrouped category) during changes in the cognitive task. Spike trains of laser-responsive neurons were more common in the I category, whereas those of laser nonresponsive neurons were more common in the NG category. Therefore neuronal spike trains in the I category may mediate shifts in endogenous or cognitive pain-related behavior.

Effect of prolonged hypoxia on food consumption, respiration, growth and reproduction in marine scavenging gastropod Nassarius festivus

The effects of prolonged exposure to reduced oxygen levels (3.0 and 1.5 mg O(2)l(-1)) on marine scavenging gastropods Nassarius festivus were studied for 8 weeks. The percentages of individuals engaged in feeding and amount of food consumed were reduced as oxygen level decreased; absorption efficiency, however, did not vary significantly with oxygen level. Oxygen consumption rates and specific oxygen consumption rates were lower at reduced oxygen levels. Reproduction occurred at all oxygen levels with less egg capsules being produced at lower oxygen levels. Egg size and number of eggs per capsule, however, were not significantly affected by oxygen level. The increase in shell length was 12%, 6% and 5% at 6.0 mgO(2)l(-1) (normoxia), 3.0 mgO(2)l(-1) and 1.5 mgO(2)l(-1), respectively. At the end of the experiment, the amount of energy allocated to growth and reproduction decreased at reduced oxygen levels with values obtained at 3.0 mgO(2)l(-1) and 1.5 mgO(2)l(-1) being 48% and 70% lower than those at 6.0 mgO(2)l(-1). At all oxygen levels, most of the accumulated energy was allocated to shell growth and reproduction, and the amount allocated to somatic growth was relatively insignificant. The reduction in energy allocated to reproduction was greater than that to shell growth as the oxygen level was reduced, indicating a strategic energy allocation of marine scavengers under stressful conditions to enhance survival.

More evidence supports the association of PPP3CC with schizophrenia

Calcineurin is a calcium/calmodulin-dependent protein phosphatase composed of two subunits, a regulatory subunit of calcineurin B (CNB) and a catalytic subunit of calcineurin A (CNA). PPP3CC is the gamma isoform of CNA located at the chromosome 8p21.3 region. To evaluate the association between PPP3CC and schizophrenia in the Taiwanese population, 10 single nucleotide polymorphism (SNP) markers across the gene were genotyped by the method of MALDI-TOF in 218 schizophrenia families with at least two affected siblings. One SNP (rs2272080) located around the exon 1 untranslated region was nominally associated with schizophrenia (P=0.024) and significantly associated with the expression of PPP3CC in lymphoblast cell line; the TT and TG genotype had significantly higher relative expression levels than the GG genotype (P=0.0012 and 0.015, respectively). In further endophenotype stratification, the single locus of rs2272080 and the haplotypes of both two-SNP haplotype (rs7833266-rs2272080) and seven-SNP haplotype (rs2461491-rs2469758-rs2461489-rs2469770-rs2449340-rs1482337-rs2252471) showed significant associations with the subgroup of schizophrenia with deficits of the sustained attention as tested by the continuous performance test (CPT, P<0.05) and the executive functioning as tested by the Wisconsin Card Sorting Test (WCST, P<0.05). The results suggest that PPP3CC gene may be a true susceptibility gene for schizophrenia.

Occurrence of organic chemicals in two rivers inhabited by Ozark hellbenders (Cryptobranchus alleganiensis bishopi)

Ozark Hellbender (Cryptobranchus alleganiensis bishopi) populations are in decrease throughout their native range with rare recruitment of young. Increased estrogenic chemical levels and alterations of physicochemical properties in their habitat may play a significant role in this phenomenon. We report here the first systematic, comprehensive study of organic chemical concentrations and physical and nutrient parameters in two rivers containing Ozark hellbender populations. Water samples were collected monthly from August 2003 to November 2004. Concentrations of 21 organic chemicals were determined using gas chromatography-mass spectrometry. Nine organic chemicals were detected. Benzyl butyl phthalate, dibutyl phthalate, bisphenol A, and beta-sitosterol were all detected >85% of the time, with median concentrations of 18 to 234 ng/L and maximum concentrations of 198 to 4141 ng/L. Individually, concentrations of nutrients and organic chemicals were much lower than those shown previously in laboratory and field experiments to have reproductive effects on amphibians. Nevertheless, hellbenders are exposed to a variety of chemicals with potential estrogenic effects. Our study establishes the basis to examine the specific effects of the detected concentrations, alone and in combination, on the Ozark hellbenders.

Generation of two-dimensional chaotic vector fields from a surface-emitting semiconductor laser: analysis of vector singularities

We demonstrate experimental generation of two-dimensional (2D) chaotic vector fields from a surface-emitting microcavity laser with precisely control of the operating temperature and the operating current. The 2D optical vector field is found to be formed by frequency locking of two linearly polarized laser modes with different chaotic spatial structures. The eigenfunction expansion method is used to reconstruct the experimental wave function for analyzing the properties of the vector singularities. It is shown that the distribution of vector singularities obeys the sign rule of nearest-neighbor singularities in the phase space of the vector field.

Statistical properties of experimental coherent waves in microcavity lasers: analogous study of quantum billiard wave functions

We use a microcavity laser to explore the properties of experimental coherent waves as an analogous study of the chaotic wave functions in quantum billiards. With the eigenstate expansion method, the experimental high-order chaotic coherent waves are well reconstructed. The reconstructed wave functions are employed to calculate the field and intensity correlations. It is found that the spreading of k-space (momentum space) distribution leads to not only wave localization in coordinate space but also enhancement of long-range correlations.

Wave functions with localizations on classical periodic orbits in weakly perturbed quantum billiards

We analytically investigate quantum wave functions with localizations on classical periodic orbits (POs) in the circular billiards. We construct the coherent states which are the coherent superpositions of nearly degenerate eigenstates and found to be localized around single classical POs. With the constructed coherent states, we can analytically express the mesoscopic eigenstates in the weakly perturbed systems, which are found to be localized on the ensemble of classical POs. Furthermore, these coherent states can be utilized to study the quantum vortex structures in quantum billiards.

Effects of the electrode arrangements on reductive dechlorination of trichloroethylene in an electro-enhanced iron wall

This study examined the factors that influence the reductive dechlorination of trichloroethylene (TCE) when direct current is externally supplied to a laboratory scale iron wall. Experimental results indicated that an anode electrode was placed in contact with the iron filling near the inlet of the column, and then a cathode was located on the top of the column. Excellent TCE degradation efficiency was displayed. The surface of the iron particles was acid-washed by H+, owing to water oxidation around the anode, and large quantities of Fe2+ were produced as a reductant which enhanced the TCE degradation, due to iron corrosion caused by the supply of external electrons. The cathode should be placed in sand fill atop the iron filling in order to avoid the formation of iron (hydr) oxide precipitates on the surface of the iron particles when the pH increases as a result of the release of OH+ around the cathode. Due to more H+ being released, which benefited the acid-washing of the iron filling, the TCE removal efficiency increased from 32% to 100% when the electric potential increased to 60V. However, black precipitates of iron (hydr) oxide were observed coated on the iron surface, causing the blocking of pores in the iron wall with the increase in the electric potential application. The efficiency of TCE degradation was almost equal regardless of groundwater velocity when direct current was applied to the iron wall. Based on observations of TCE degradation during long-term operations, the TCE removal efficiency in the effluent reached 100% after seven days of operation and maintained this high level after 25 days of operation. Thus, iron wall by electroremediation displayed excellent potential for development in long-term operations.

Impact of an outbreak of severe acute respiratory syndrome on a hospital in Taiwan, ROC

STUDY OBJECTIVE

To estimate the impact of the severe acute respiratory syndrome (SARS) outbreak in early 2003 on a tertiary care hospital in Taiwan, ROC.

METHODS

The study estimated the utilisation of resources related to infection control, SARS related medical services, and routine medical services, and SARS related medical outcomes at National Cheng Kung University Hospital (NCKUH) from 25 March to 16 June 2003 through a cross sectional survey of hospital records.

RESULTS

A mean of 5100 persons per day (95%CI 4580 to 5610) underwent fever screening at the outpatient and emergency department (ED) entrances to the hospital, of which 35 per day (95% CI 30 to 40) were referred for further evaluation for suspected or probable SARS. ED isolation surge capacity was created via 12 new beds outside the ED: eight for SARS assessment, three for patients awaiting in hospital bed assignment, and one for resuscitation. A total of 382 patients were fully evaluated for suspected or probable SARS outside the ED, of which 27 were admitted. The mean numbers of outpatient clinic patient visits, ED visits, ED trauma patient visits, ED admissions, hospital admissions, and operative procedures decreased during the outbreak. Thirty eight patients were hospitalised with suspected SARS, of which three received the final diagnosis of probable SARS. Two patients with probable SARS died. No cases of nosocomial SARS transmission occurred.

CONCLUSIONS

This SARS outbreak was associated with substantial use of hospital and ED resources aimed at infection control, comparatively less use of resources related to the medical care of patients with suspected or probable SARS, and decreased use of routine medical services.

Antibody-mediated endothelial cell damage via nitric oxide

Vascular disorders, resulting from endothelial cell dysfunction, may be caused by various stimuli, including infectious pathogens, cytotoxic reagents, and pathophysiological mechanisms mediated by immune responses. Endothelial cell dysfunction characterized by apoptosis and abnormal immune activation is, at least in part, induced by anti-endothelial cell antibody (AECA) in some cases of autoimmune disease. However, the molecular mechanisms of AECA-mediated pathogenetic damage to host vascular system remain unclear. The dual role of nitric oxide (NO) both in endothelial cell apoptosis and survival has been described. In this paper, endothelial cell apoptosis caused by the presence of cross-reactive AECA via a NO-mediated mechanism is demonstrated in dengue virus infection. Endothelial cells undergo apoptosis via the mitochondria-dependent pathway that is regulated by NO production. NO-regulated endothelial cell injury thus may play a role in the disruption of vessel endothelium and contribute to the AECA-induced pathogenesis of vasculopathy. The modulation of NO may provide the therapeutic strategies for autoimmune diseases by preventing the AECA-mediated endothelial cell damage.

Effects of estrogen on gender-related autonomic differences in humans

Our previous studies demonstrated that premenopausal women have dominant vagal and subordinate sympathetic activity compared with age-matched men. This study was designed to investigate the role of estrogen in gender-related autonomic differences. We evaluated the heart rate variability of four healthy groups: age-matched postmenopausal women without hormone replacement therapy (PM), postmenopausal women on conjugated estrogen replacement therapy (PME), men, and non-age-matched premenopausal women (PreM). Frequency-domain analysis of short-term and stationary R-R intervals was performed to evaluate low-frequency power (LF; 0.04-0.15 Hz), high-frequency power (HF; 0.15-0.40 Hz), the ratio of LF to HF (LF/HF), and LF in normalized units (LF%). No gender-related autonomic differences existed between the PM and men groups, but they did exist between the PME and men group. Compared with the PreM group, the PM group had a lower HF and higher LF% and LF/HF. Compared with the PM group, the PME group had a higher HF but lower LF% and LF/HF. These results suggest that conjugated estrogen replacement therapy may facilitate vagal and attenuate sympathetic regulation of heart rate in postmenopausal women. In addition, estrogen may play an important role in gender-related autonomic differences.

Elasticity of alveolar bone near dental implant-bone interfaces after one month's healing

Information is scarce about Young's modulus of healing bone surrounding an implant. The purpose of this preliminary study is to quantify elastic properties of pig alveolar bone that has healed for 1 month around titanium threaded dental implants, using the nanoindentation method. Two 2-year-old Sinclair miniswine were used for the study. Nanoindentation tests perpendicular to the bucco-lingual cross section were performed on harvested implant-bone blocks using the Hysitron TriboScope III. Nomarski differential interference contrast microscopy was used to identify pyramidal indentation measurements that were from bone. Reduced moduli, averaged for all anatomical regions, were found to start low (6.17 GPa) at the interface and gradually increase (slope=0.014) to a distance of 150 microm (7.89 GPa) from the implant surface, and then flatten to a slope of 0.001 from 150 to 1500 microm (10.13 GPa). Mean reduced modulus and its relationship to distance did not differ significantly by anatomic location (e.g., coronal, middle, and apical third; P>/=0.28 for all relevant tests) at 1 month after implantation.

Hierarchical rule-based monitoring and fuzzy logic control for neuromuscular block

OBJECTIVE

The important task for anaesthetists is to provide an adequate degree of neuromuscular block during surgical operations, so that it should not be difficult to antagonize at the end of surgery. Therefore, this study examined the application of a simple technique (i.e., fuzzy logic) to an almost ideal muscle relaxant (i.e., rocuronium) at general anaesthesia in order to control the system more easily, efficiently, intelligently and safely during an operation.

METHODS

The characteristics of neuromuscular blockade induced by rocuronium were studied in 10 ASA I or II adult patients anaesthetized with inhalational (i.e., isoflurane) anaesthesia. A Datex Relaxograph was used to monitor neuromuscular block. And, ulnar nerve was stimulated supramaximally with repeated train-of-four via surface electrodes at the wrist. Initially a notebook personal computer was linked to a Datex Relaxograph to monitor electromyogram (EMG) signals which had been pruned by a three-level hierarchical structure of filters in order to design a controller for administering muscle relaxants. Furthermore, a four-level hierarchical fuzzy logic controller using the fuzzy logic and rule of thumb concept has been incorporated into the system. The Student's test was used to compare the variance between the groups. p < 0.05 was considered significant.

RESULTS

The system achieved stable control of muscle relaxation with a mean T1% error of -0.19 (SD 0.66) % accommodating a range in mean infusion rate (MIR) of 0.21-0.49 mg x kg(-1) x h(-1). When these results were compared with our previous ones using the same hierarchical structure applied to mivacurium, less variation in the T1% error (p < 0.05) but the same variation in infusion rate were observed. The controller activity of these two drugs showed no significant difference (p > 0.5). However, the consistent medium coefficient variance (CV) of the MIR of both rocuronium (i.e., 36.13 (SD 9.35) %) and mivacurium (i.e., 34.03 (SD 10.76) %) indicated a good controller activity.

CONCLUSIONS

The results showed that a hierarchical rule-based monitoring and fuzzy logic control architecture can provide stable control of neuromuscular block despite the considerable individual variation in neuromuscular block required among patients. Also, there was less variation in T1% error compared with that of previous study on mivacurium. Meanwhile, the consistent medium CV of the MIR of both rocuronium and mivacurium indicated a good controller activity which is able to withstand noise, diathermy effect, artifacts and surgical disturbances.

Adaptive phase field simulation of dendritic growth in a forced flow at various supercoolings

An efficient finite volume method is developed for the phase-field simulation of two-dimensional dendritic growth in a forced flow at various supercoolings. The adaptive nature of the method allows the dendrite in a large domain to evolve secondary structures, even at low supercoolings. In addition to good agreement with previous calculations on the tip shape and speed, the effects of forced flow at various supercoolings are investigated and compared with the Oseen-Ivantsov solution and good agreement is found. The steady dendrite shape in all cases continues to have a self-affine nature and the invariant scaling parameters are in good agreement with the estimation.

Development of hematogenous pneumococcal meningitis in adult mice: the role of TNF-alpha

Bacterial penetration across the blood-brain barrier (BBB) into the central nervous system is the first step in development of meningitis. The role of tumor necrosis factor-alpha (TNF-alpha) in the penetration process was examined with peripheral infection of Streptococcus pneumoniae type 6. After intraperitoneal infection of S. pneumoniae type 6, the BBB opening was increased continuously from 6 h and the mice died of septic shock within 36 h due to bacterial overgrowth. The bacteria crossed the BBB and began to deposit in brain at 6 h post infection. There was strong staining of TNF-alpha on blood vessels of brain from 6 h to 24 h post infection. Anti-TNF-alpha antibody blocked both the BBB opening and the entrance of circulatory S. pneumoniae type 6 into brain, indicating that TNF-alpha played an important role in controlling the opening of BBB. Furthermore, an adult murine model of hematogenous pneumococcal meningitis was developed that is based on opening of the BBB by TNF-alpha and controlling the degree of bacteremia by cefazolin antibiotic. In conclusion, hematogenous meningitis developed as TNF-alpha initiated BBB opening, peripheral bacteria entered into the brain and formed bacterial emboli, and then progressed to meningitis.

Catalytic nucleophilic acyl substitution of anhydrides by amphoteric vanadyl triflate

[reaction--see text] Among four vanadyl species examined, vanadyl triflate was the most efficient catalyst to facilitate nucleophilic acyl substitution of anhydrides with a myriad array of alcohols, amines, and thiols in high yields and high chemoselectivity. By using mixed-anhydride technique, one can achieve oleate and peptide syntheses. In marked contrast to common metal triflates, the amphoteric character of the V=O unit in vanadyl species was proven to be responsible for the catalytic profile in this process.

Proliferation characteristics of canine transmissible venereal tumor

Canine transmissible venereal tumor (CTVT) grows progressively (P-phase) in the host and then spontaneously regresses (R-phase). The mechanisms behind the transition from the P-to R-phases are not well understood. In this study, in order to determine the proliferation characteristics of CTVT, we evaluated telomerase activity and enumerated nuclear organizing regions (AgNOR) and proliferating cell nuclear antigen (PCNA). It was found that CTVT cells from the P-and R-phases were both positive for telomerase activity, although it was lower in the R-phase. Evaluations of telomerase activity should take into account the stage of mitosis. Although, in the majority of cases, telomerase activity can be used to differentiate between benign and malignant tumors in dogs, other factors or markers should also be used to obtain accurate diagnoses. The PCNA-positive rate and the number and area of AgNOR per cell increased much more in the P-phase than the R-phase. However, the AgNOR values were always higher. Thus, the AgNOR count can be used to distinguish the P-and R-phases of CTVT. In addition, mitotic figures were much higher in number in the P-phase as compared to the R-phase. We believe that, during spontaneous regression of CTVT cells, slow tumor cell proliferation must contribute to the decrease in tumor size. However, shortening of tumor cell telomeres is not directly involved in this process. Other factors, such as expression of MHC antigens on CTVT cells, humoral immunity, cytokines released by the inflammatory cells and, especially, tumor infiltrating lymphocytes may contribute to CTVT regression.

Complete genome analysis of enterovirus 71 isolated from an outbreak in Taiwan and rapid identification of enterovirus 71 and coxsackievirus A16 by RT-PCR

Hand, foot, and mouth disease (HFMD) and encephalomyelitis were two major clinical manifestations during the 1998 enterovirus 71 (EV71) epidemic in Taiwan. To investigate whether different clinical patterns were caused by alterations in EV71 genomes, the complete nucleotide sequences of four EV71 strains associated with HFMD or encephalomyelitis were compared. Among these viral strains, two or three nucleotide differences were found within the 5'-noncoding region, and two or four amino acid differences were found within the regions encoding viral polyproteins; however, none of these differences were correlated with either clinical manifestation. Because coxsackievirus A16 was another major causative agent of HFMD, a reverse transcription-polymerase chain reaction assay, with high sensitivity and specificity for identification of EV71 (both 100%) and coxsackievirus A16 (100 and 98.8%), was developed for the rapid differential identification of these two viruses in HFMD patients.

Tumour necrosis factor-alpha causes an increase in blood-brain barrier permeability during sepsis

Blood-brain barrier (BBB) permeability during sepsis with Escherichia coli or Streptococcus pneumoniae was examined in a mouse model and measured by a circulating beta-galactosidase tracer. The leakage of brain microvascular vessels during sepsis was confirmed by transmission electron microscopic examination of brain tissues stained with horseradish peroxidase. The increase of BBB permeability induced by E. coli and S. pneumoniae, which was maximal at 3 h and 12 h after injection, respectively, was transient because of rapid clearance of the bacteria from the blood. Tumour necrosis factor-alpha (TNF-alpha) was stained on microvascular vessels of the brain during sepsis and intravenous injection of recombinant TNF-alpha also increased the BBB permeability. The increase in BBB permeability induced by either E. coli or S. pneumoniae could be inhibited by anti-TNF-alpha antibody. It was concluded that circulating TNF-alpha generated during sepsis induced the increase in BBB permeability.

Immunopathogenesis of dengue virus infection

Dengue virus infection causes dengue fever (DF), dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS), whose pathogeneses are not clearly understood. Current hypotheses of antibody-dependent enhancement, virus virulence, and IFN-gamma/TNFalpha-mediated immunopathogenesis are insufficient to explain clinical manifestations of DHF/DSS such as thrombocytopenia and hemoconcentration. Dengue virus infection induces transient immune aberrant activation of CD4/CD8 ratio inversion and cytokine overproduction, and infection of endothelial cells and hepatocytes causes apoptosis and dysfunction of these cells. The coagulation and fibrinolysis systems are also activated after dengue virus infection. We propose a new hypothesis for the immunopathogenesis for dengue virus infection. The aberrant immune responses not only impair the immune response to clear the virus, but also result in overproduction of cytokines that affect monocytes, endothelial cells, and hepatocytes. Platelets are destroyed by crossreactive anti-platelet autoantibodies. Dengue-virus-induced vasculopathy and coagulopathy must be involved in the pathogenesis of hemorrhage, and the unbalance between coagulation and fibrinolysis activation increases the likelihood of severe hemorrhage in DHF/DSS. Hemostasis is maintained unless the dysregulation of coagulation and fibrinolysis persists. The overproduced IL-6 might play a crucial role in the enhanced production of anti-platelet or anti-endothelial cell autoantibodies, elevated levels of tPA, as well as a deficiency in coagulation. Capillary leakage is triggered by the dengue virus itself or by antibodies to its antigens. This immunopathogenesis of DHF/DSS can account for specific characteristics of clinical, pathologic, and epidemiological observations in dengue virus infection.

The organic precursors affecting the formation of disinfection by-products with chlorine dioxide

The object of this research was to study the formation of disinfection by-products by using chlorine dioxide (ClO2) as a disinfectant reacting with different properties of organic substance in natural aquatic environment. The adsorbent resin (XAD-4, XAD-7) was used to divide the organic matters in raw water into three groups. The influence of the function groups on structure, reaction tendency, and formation of disinfection by-products generated by the reaction of these organic substances with chlorine dioxide was explored. The experimental results show that the three different organic groups formed using adsorbent resin were hydrophobic substance, hydrophilic acid, and non-acid hydrophilics in proportions of 43%, 41%, and 16%, respectively. Within the raw water in our study, the hydrophilic substance had a higher distribution proportion than that described in general articles and journals, which indicates that this water was contaminated with pollution from human beings. The exploration of the reactivity of the three different organic substances with chlorine dioxide shows that the unit consumption of disinfection agent per unit organic matters (represented by ClO2/DOC) is in the following sequence hydrophobic substance > hydrophilic substance > non-acid hydrophilics. It indicated that larger molecular organic precursors had larger consumption of disinfectant. We also discovered that after the reaction of the three different organic substances with chlorine dioxide, the largest amount of disinfection by-products were generated by the non-acid hydrophilics.

Choroidal masses: a fourteen-year analysis

BACKGROUND

Choroidal masses present much diversification in clinical features and incidence. The purpose of this study is to investigate the epidemiological and clinicopathological manifestations of different choroidal tumors in order to tabulate appropriate diagnostic approaches.

METHODS

A retrospective analysis of patients with choroidal masses was conducted, the analysis being based upon the review of our medical records from January 1986 to December 1999 inclusively. A definite diagnosis of choroidal mass was confirmed by at least two experienced ophthalmologists. For patients who were enrolled in this study, an ophthalmic examination was conducted and medical history was recorded. Some ancillary tests, such as indirect ophthalmoscopy, ultrasonography, fluorescein angiography, computed tomography, and magnetic resonance imaging, were used to support the accuracy of our diagnoses.

RESULTS

A total of 149 patients were enrolled in this study, of which 103 cases were excluded due to a loss of follow-up or incomplete medical records. Forty-six patients (51 eyes) included 12 cases (26%) of malignant metastases, 10 cases (22%) of hemangiomas, 2 cases (4%) of osteomas, 5 cases (11%) of melanocytomas, 8 cases (17%) of melanomas, and 9 cases (20%) of other melanocytic lesions. The male to female ratio was 21:25. The average length of follow-up was 20.5 months, and the average age of these patients was 42.8 years. Presenting with varied clinical incidence and pictures, each category of choroidal mass was investigated thoroughly.

CONCLUSION

With more clinical experience and a better understanding of choroidal masses, we are able to propose an early differential diagnosis and therapeutic approach to the effective management of them in order to minimize ocular morbidity and improve patients' survival and quality of life.

Apoptosis of skeletal muscle cells and the pathogenesis of myositis: a perspective

Apoptosis is a genetically controlled form of cell death that occurs in many biologic processes including embryogenesis, immune cell development, and maintenance of peripheral immune tolerance. Recent studies have yielded evidence suggesting that apoptosis of parenchymal cells may play a role in providing self-antigens to initiate autoimmune reactions. Skeletal muscle cells are fully differentiated and multinucleated. Apoptosis has been described in developing myoblasts and, recently, in mature myotubes. However, the involvement of apoptosis in skeletal muscle pathologies is unclear. This article reviews the available data concerning the occurrence of skeletal muscle cell apoptosis in selected muscle diseases. It also discusses the potential role of muscle cell apoptosis in the development of autoimmune diseases such as idiopathic inflammatory myopathies.

A comparison of clinical use of fluticasone propionate and beclomethasone dipropionate in pediatric asthma

Inhaled steroids play a very important role in the prevention and treatment of asthma. Previous studies indicated that fluticasone propionate (FP) had low bioavailability and high local potency. However, the laboratory data in these studies were not obtained among Taiwan population. It is very important that native data should be established. Thus a 12-week research program was designed, involving 77 patients, 51 for FP group and 26 for beclomethasone dipropionate (BD) group. The objects were victims of moderate to severe asthma and their age ranged from 4 to 14 years old. An open, comparative and randomized method was adopted. Except for the 4-week-later daytime symptom score(P = 0.033, BD group was better), no other significant differences were found between the two groups in the symptom score improvement(P > 0.05). All the P-values for the daytime & night-time scores were lower than 0.001, which means obvious improvement after treatment in both groups. P-value for PEF improvement was 0.003 after 4 weeks (BD group was better) and 0.943 after 8 weeks; for FEV1 improvement, it was 0.005 after 4 weeks(BD group was better) and 0.252 after 8 weeks; and for FEV1/FVC improvements, it was 0.067 after 4 weeks and 0.097 after 8 weeks. There was no statistic significance in total eosinophil count (TEC), IgE, eosinophil cationic protein (ECP) serum level changes after 4 or 8 weeks. Adverse effects were all anticipated and no statistic significance showed up, either, between the two groups or in the cortisol levels (P > 0.05). In conclusion, native data indicated that the potency of 100 micrograms of FP was equal to that of 200 micrograms of BD and that few side effects were noted in FP group. It is recommended that this drug be introduced for clinical use.

Structural dynamics of oligodendrocyte lysis by perforin in culture: relevance to multiple sclerosis

The mechanism by which oligodendrocytes are depleted from active lesions in multiple sclerosis (MS) is not clear but many reports implicate a cytolytic process. The most applied animal model for MS, chronic relapsing experimental autoimmune encephalomyelitis (EAE), has been established in inbred strains of mice, especially SJL and PL. Studies on oligodendrocytes from these strains in vitro have been hampered to date by an inability to grow these cells from mouse CNS tissue. We report here a successful method to culture SJL mouse oligodendrocytes and have analyzed lysis of these cells in vitro mediated by the pore-forming protein, perforin, a candidate effector molecule in inflammatory demyelination. Cultures were exposed to murine perforin, 36-72 hemolytic U, for up to 2.5 hr and examined using the oligodendrocyte phenotypic markers O4, galactocerebroside and myelin basic protein (MBP), in addition to a membrane dye (DiI) and a marker of necrosis, propidium iodide, (PI). Cultures were imaged chronologically by phase contrast, immunofluorescence, digital, light and electron microscopy. Findings showed that the majority of oligodendrocytes were killed within 60-90 min via pore expansion and ultimately, membrane disruption. The structural features of the cellular damage comprised swelling of the cell body, fenestration and fragmentation of membranes and processes, cytoplasmic vacuolation and breakdown of the nuclear envelope. Astrocytes in the same system were relatively resistant to cell lysis. The above patterns of oligodendrocyte damage in SJL oligodendrocytes were reminiscent of patterns in the MS lesion, leaving us to conclude that perforin may play an important role in the human disease.

Parental concerns for the child with febrile convulsion: long-term effects of educational interventions

OBJECTIVE

To evaluate long-term effects of educational interventions on parental concerns for children with febrile convulsions (FC).

SUBJECTS AND METHODS

209 FC parents were recruited from southern Taiwan, and assigned into program or pamphlet groups by their choices. A questionnaire was used to examine the parental concerns at 4 time points: prior to the interventions, 3 months, 1 year, and 2 years after the interventions.

RESULTS

The concern scores were high before the interventions. Parents concerned that their child is apt to get a fever, has further seizures in the night, that FC results in potential brain damage and is life threatening. After interventions the concern scores were significantly lower for the program group than for the pamphlet group. The educational program was the most significant factor that influenced the change in parental concerns. The recurrence of FC did not significantly influence the change in the concern trajectory in the program group but showed a significant difference in the pamphlet group.

CONCLUSION

FC parental concerns decreased as time passed particularly in the program group. The educational program was the significant factor that influenced the change of concern trajectories, and the recurrent/non-recurrent factor influenced the change of concern only in pamphlet group. FC parental concerns should be assessed, and information given combined with emotional support.

Bladder wall calcification after intravesical chemotherapy with mitomycin C--a case report

Bladder wall calcification has relatively few etiologies. We present such a case and review the literature to discuss it and the method for management. This case suffered from bladder wall calcification about 3 years after intravesical chemotherapy of mitomycin C. It was found accidentally during the transurethral resection of recurrent bladder tumor. The pathology confirmed the recurrence of transitional cell carcinoma combined with marked calcification. A repeat cystoscopy was done 3 months later. Massive calcified deposits in bladder wall especially in lesion of previous transurethral resection were still noted. Randomized biopsy showed dystrophic calcification without evidence of malignancy. We suggest that biopsy and/or resection (if possible) is a reasonable approach to eliminate the possibility of invasive bladder cancer.

Cloning and characterization of a novel variant of rat GABA(B)R1 with a truncated C-terminus

The gamma-aminobutyric acid B receptor (GABA(B)R) belong to the G-protein-coupled receptor superfamily and has been identified as a mediator in the transmission of slow inhibitory neurotransmission in the mammalian central nervous system. Two types of GABA(B)R have been cloned, GABA(B)R1 and R2. GABA(B)R2 is co-expressed with GABA(B)R1 in many brain regions and inwardly rectifying potassium channels are activated by GABA(B)R agonists only upon co-expression of GABA(B)R1 with GABA(B)R2. Several splice variants of GABA(B)R1 receptors have been cloned from rat brain library. Using a rat hippocampal cDNA library, we have isolated a novel cDNA clone of GABA(B) receptor containing an insert of 124 bp between exon 3 and exon 4. This insert occurred between the regions encoding the Sushi domain and leucine binding protein (LBP)-like domain. The insert and subsequent frame shift generated a cDNA that codes for a truncated polypeptide of 239 amino acids lacking the C-terminus. Analysis of the deduced amino acid sequence of the new cDNA clone, termed GABA(B)R1g, showed that it was identical to the first 157 amino acids of GABA(B)R1a, but diverged thereafter. The C-terminal region of GABA(B)R1g contained two cysteine residues. GABA(B)R1g was expressed in both brain and peripheral tissues. Northern blot analysis demonstrated that two transcripts (4.5 kb and 4.0 kb) exist in hippocampus. In addition, studies of hippocampus in developing animals indicated that the expression of GABA(B)R1g is maximal at postnatal day four. GABA(B)R1g could be generated by alternative splicing of the GABA(B)R1 gene.

RINT-1, a novel Rad50-interacting protein, participates in radiation-induced G(2)/M checkpoint control

Rad50, an structural maintenance of chromosomes (SMC) protein family member, participates in a variety of cellular processes, including DNA double-strand break repair, cell cycle checkpoint activation, telomere maintenance, and meiosis. Disruption of Rad50 in mice leads to lethality during early embryogenesis, indicating its essential function in normal proliferating cells. In addition to its ability to form a complex with the DNA double-strand break repair proteins Mre11 and NBS1, Rad50 may interact with other cellular proteins to execute its full range of biological activities. A novel 87-kDa protein named RINT-1 was identified using the C-terminal region of human Rad50 as the bait in a yeast two-hybrid screen. Human RINT-1 shares sequence homology with a novel protein identified in Drosophila melanogaster, including a coiled-coil domain within its N-terminal 150 amino acids, a conserved central domain of about 350 amino acids, and a C-terminal region of 90 amino acids exhibiting 35--38% identity. The conserved central and C-terminal regions of RINT-1 are required for its interaction with Rad50. While Rad50 and RINT-1 are both expressed throughout the cell cycle, RINT-1 specifically binds to Rad50 only during late S and G(2)/M phases, suggesting that RINT-1 may be involved in cell cycle regulation. Consistent with this possibility, MCF-7 cells expressing an N-terminally truncated RINT-1 protein displayed a defective radiation-induced G(2)/M checkpoint. These results suggest that RINT-1 may play a role in the regulation of cell cycle control after DNA damage.

Activation of coagulation and fibrinolysis during dengue virus infection

Dengue virus infection can induce mild dengue fever (DF) or severe dengue hemorrhagic fever and dengue shock syndrome (DHF/DSS) in human. The pathogenesis of hemorrhage in dengue virus infection is not fully understood. Since hemostasis depends on the balance between coagulation and fibrinolysis, alternation of some coagulation parameters (platelet count and activated partial thromoboplastin time, APTT) as well as fibrinolytic parameters (tissue plasminogen activator, tPA and plasminogen activator inhibitor-1, PAI-1) were compared in 8 DHF/DSS and 17 DF patients. Patients showed thrombocytopenia, APTT prolongation, and tPA increase in the acute stage of disease, indicating activation of coagulation and fibrinolysis. The activation of coagulation and fibrinolysis in DHF/DSS patients was much more severe than DF patients. In the convalescent stage, a rise of PAI-1 level and platelet count with concomitant decline of tPA level and APTT returned to normal in both DHF/DSS and DF patients. Therefore, the activation of coagulation and fibrinolysis during the acute stage of dengue virus infection is offset by the increase of platelet and PAI-1 during convalescent stage. Taken together, these results suggest that the degree of coagulation and fibrinolysis activation induced by dengue virus infection is associated with the disease severity.

Surgery for lung abscess in immunocompetent and immunocompromised children

PURPOSE

The aim of this study was to evaluate the surgical management results of lung abscess in immunocompetent and immunocompromised children.

METHODS

Surgery was performed on 30 children with lung abscess or necrotizing pneumonia refractory to medical treatment in a 12-year period. Of them, 23 were immunocompetent, and 7 were immunocompromised. Pulmonary resection was performed including unilateral lung in 28, bilateral in 2, and 2 lobes in 6. Concomitant decortication was performed in 18 (78.2%) immunocompetent patients.

RESULTS

Increased incidence of surgery for lung abscess was caused mainly by drug-resistant and fungal infection. Surgery was performed commonly for bacterial lung abscess on patients less than 5 years old and fungal lung abscess on adolescence. A multiple small abscess was the predominant type of abscess in immunocompetent patients, whereas 2-lobe involvement tended to occur in immunocompromised patients. Fungal lung abscess tended to occur on left lung and in female patients. Left lower lobe was involved most commonly in both groups of patients in which majority need lobectomy. Immunocompromised patients required a more extensive pulmonary resection. There were 3 postoperative complications (morbidity of 10.2%) with no postoperative mortality. Length of postoperative hospital stay ranged from 6 to 85 days with average of 18.4 days.

CONCLUSIONS

The incidence and pattern of lung abscess that required surgery between immunocompetent and immunocompromised children were different. A more aggressive, extensive surgical procedure is preferable for immunocompromised patients, and the surgical results were comparatively excellent to immunocompetent patients. However, the prognosis of immunocompromised children depends on their underlying disease process.

Diagnosis of appendicitis in the ED: comparison of surgical and nonsurgical residents

The purpose of this study was to evaluate the impact of a surgery-based (SB) versus nonsurgery-based (NSB) training background of residents on the diagnosis of acute appendicitis in the emergency department (ED). The medical records of 641 adult patients who had undergone an appendectomy during a 3-year period (July 1996 to June 1999) were reviewed. All the patients were divided into NSB-in charge (n = 367) and SB-in charge (n = 274) groups, and demographic and clinical data recorded. Both groups' patients showed no differences in either negative appendectomy or perforation rates. However, NSB group patients had longer in-hospital delays in comparison with SB group patients (12.0 +/- 0.7 versus 9.6 +/- 0.4 hours, P <.05). This longer stay time mainly occurred in the patients with negative exploration and uncomplicated appendicitis P <.05). In both groups, patients with complicated appendicitis had longer prehospital delay of presentation than those with uncomplicated appendicitis. (2.0 +/- 0.2 versus 1.2 +/- 0.1 days in NSB group; 2.5 +/- 0.5 versus 1.3 +/- 0.2 days in SB group, P <.01). The NSB residents tended to order more computed tomography (CT) scans than SB residents (12% versus 5.1%, P <.05). With the application of a CT scan, the negative appendectomy rate was reduced significantly from 23% to 12%. We concluded that under the supervision of board-certified emergency physicians, the NSB residents had capabilities similar to SB residents in making correct diagnoses of acute appendicitis. In addition, close observation of equivocal cases in the ED did not necessarily increase the perforation rate.