Prevalence of childhood asthma based on questionnaires and methacholine bronchial provocation test in Korea

BACKGROUND

In most epidemiological survey studies, only subjective symptoms and past medical history of asthma have been used as diagnostic criteria. Even though a questionnaire survey can be performed in a large population study at low cost, limitations such as lack of objectivity and poor predictability in non-specific bronchial hyperresponsiveness cannot be avoided.

OBJECTIVES

The purpose of this study was to elucidate the prevalence of current asthma based on questionnaires and methacholine bronchial provocation test, and the prevalence of atopy in Korea.

METHODS

We performed modified ATS respiratory questionnaires and allergen skin-prick test with 10 common inhalant allergens among 3219 subjects aged 7-19 years in Seoul and a rural part of a small city, Chungju in Korea. Methacholine bronchial provocation tests were also performed among those who had asthma symptoms according to the questionnaire. The criteria of asthma was presence of both asthma symptoms and non-specific bronchial hyperresponsiveness. Atopy was defined as when an allergen induced weal size is same or larger than that caused by histamine.

RESULTS

The prevalence of asthma based on questionnaires and methacholine bronchial provocation tests was 4.6%, while the prevalence of wheeze was 8.2% and 19.3% of total population complained of one or more respiratory symptoms related to asthma on the questionnaires. There was no significant difference according to age, sex and living area. The mean prevalence of atopy was 35.0% and the most common allergens were Dermatophagoides farinae (30.9%), Dermatophagoides pteronyssinus (27.5%), cat fur (20.4%) and cockroach (11.8%). The atopy prevalence in Chungju area was higher than that in Seoul and males showed a higher prevalence than females. The asthma prevalence was higher among atopics (6.8%) than among non-atopics (2.7%). None of questionnaire items were enough to predict the presence of bronchial hyperresponsiveness in terms of sensitivity, specificity and positive predictive value.

CONCLUSION

The prevalence rate of current asthma in Korea was 4.6% and the prevalence rate of atopy in Korea was 35.0%. Questionnaire-based surveys are not enough to predict the actual prevalence of asthma.

Outcome of pediatric patients with severe brain injury in Korea: a comparison with reports in the west

There have been relatively wide variations in the results of studies examining the outcomes of severe brain injury in children. Among the reasons for these variations in outcome, prehospital care can be considered as one of the factors. In Korea, major hospitals use an aggressive and sophisticated management policy very similar to that practiced in the West. However, effective prehospital management, such as emergency care at the scene of injury and during transport by paramedics, have not yet been established. In order to evaluate the influence of prehospital care on the outcome in severely brain-injured children, we report the outcome recorded in 73 pediatric patients treated in our hospital following severe brain injury and compare these results with those reported from centers in the western community, where well-trained paramedic care and an excellent transfer system are in operation. The overall mortality rate in our patients was 23%; 41% had a good recovery, 22% moderate disability, and 12% severe disability, and 1% remained in a vegetative state. In conclusion, we would like to suggest that prehospital care does not remarkably influence mortality rates in severely brain-injured children.

Focusing-grating-coupler arrays for uniform and efficient signal distribution in a backboard optical interconnect

Several one-dimensional arrays of focusing grating couplers are designed for uniform distribution of incident optical powers to several processing boards in a backboard interconnection scheme. As main design parameters, both the length and the duty cycle of each focusing grating coupler are determined on the bases of ray-optic propagation-mode analysis in a slab waveguide and of rigorous coupled-wave diffraction analysis for out-coupled radiation modes. The backboard interconnection scheme incorporating the one-dimensional focusing-grating-coupler arrays, when used to distribute a guided optical power of TE(0) mode to several converging waves radiated only toward a glass substrate, displayed a power uniformity of 5% and a total coupling efficiency of 99.1%, which can be highly acceptable in practical use.

Sulfonated polystyrene as a new gradient-index medium for light-focusing elements

We have discovered that the sulfonation of polystyrene can form a gradient-index medium useful for lightfocusing purposes. We found that the refractive index of sulfonated polystyrene varies with the degree of sulfonation and that the refractive index of the fully sulfonated polystyrene decreased by approximately 0.06 at 0.633 microm from that of pure polystyrene.

Planar optical configurations for crossover interconnects

Two planar optics configurations for crossover interconnects are described, and the interconnection capacity of each configuration is derived on the basis of Gaussian beams' being relayed by microlens arrays. To reduce the optical path differences between bypass- and exchange-connection routes in the crossover configurations, we propose the use of two different substrates.

Three dimensional structures of pulmonary elastin; airway vs vascular elastin

Elastin is known to occur in the lung parenchyma and pleura as well as in the pulmonary vessels, but no detailed studies of this elastin's linkage between them have been done in three dimensions. For many years we have known that there is abundant elastin in the mammalian lungs, which may be associated with etiology of causing emphysema. We have developed selective casting methods to allow us to determine the location where elastin is found morphologically. The method involves casting either the vasculature via the right ventricle, or the airways via the trachea in the air sacs. Studies of the vasculature were done with the lung inflated to 80% of the vital capacity. The casted lungs were then put in 0.1 N NaOH at 75 degrees C for 48 hours, turning them frequently. THis method removed all non-elastin tissues. The scanning electron microscopy (SEM) was used to reveal the three dimensional pictures of elastin structures from both lung parenchyma and pulmonary vessels. Elastin was seen as fenestrated sheets and some fibers in both the vessels and the airways. Elastin in the two different locations was often interconnected. Studies on 6 dogs, 8 rabbits, and 2 pigs showed no significant species difference at the level of resolution of the SEM, which was used to study the specimens after they had been freeze-dried.

Variations in strength of the porcine aorta as a function of location

Dissecting aneurysms split the wall of the aorta and other large arteries to create a false lumen in parallel with the true lumen. Experiments were designed to determine the pressure required to tear the media and the work required per unit area to propagate the dissection once it started. India ink was injected into the media of 17 opened porcine aortas through a needle inserted parallel to the lumen of opened aortas placed in a saline bath. The ink was infused at 0.9 ml/min with a constant infusion pump as the pressure was monitored with a pressure transducer. The size of the bleb formed by the ink in the media was recorded with a video camera mounted perpendicular to the lumenal surface. All data were recorded on a computer. The pressure-volume curve was used to obtain the distensibility of the media (the upslope), the peak pressure, the tearing pressure, and the work of dissection (the area under the P-V curve once tearing occurred). The projected area of the bleb was calculated from the video images, and the work/area was calculated. The peak pressures were always extremely high, and ranged from 634 +/- 204 (SD) mmHg for the lower abdominal aorta to 816 +/- 145 mmHg for the lower thoracic aorta. The work/area ranged from 1.88 +/- 0.89 mJ/cm2 for the upper abdominal aorta to 11.34 +/- 4.05 mJ/cm2 for the lower abdominal aorta. An ANOVA showed that the lower abdominal aorta tore at lower pressures initially, but required much more energy to propagate the dissection. We believe that this is because of structural differences in the elastin pattern in the abdominal aorta.

Optical perfect-shuffle interconnection using a computer-generated hologram

We propose the use of a computer-generated hologram that combines a fanout and focusing element that can be used to perform an optical perfect-shuffle interconnection. The hologram is designed by calculation of the interference fringes between diverging waves from four point sources and a reference plane wave. With this element we show experimentally the resulting perfect-shuffle pattern. The use of the computer-generated hologram makes it easy to implement a planar optical perfect-shuffle interconnect, which is compact, has low aberration, and is easy to align. The planar optics configuration for a perfect-shuffle interconnection network is also discussed.

Development of elastin layers in the aortic wall of human fetuses

The presence of elastin layers in the aortic walls of twelve human fetuses was confirmed with scanning electron microscope pictures after hot alkali treatment and histochemical examination. In addition, the number of elastin layers in aortic walls of 5 different segments were compared in fetuses of varying ages. Aldehyde fuchsin stained slides of elastin ascending aortas showed a range between 27 and 55 layers of elastin in fetuses of 8 weeks to 32 weeks. However, in the lower abdominal aortas, elastin layers decreased from 28 to only 3 layers for fetuses of the same age. Furthermore, as elastin layers decreased from ascending aorta to abdominal aorta with the progression of fetal life, similar changes in the elastin lamellae were observed. These results suggest that while aortas grow rapidly in length, the medial elastin thickens slowly, perhaps due to slow development of hydrodynamic forces and pressures. Also the adventitial elastin appears to lose out gradually along the length from ascending aorta to abdominal aorta.

Compartmental analysis of RBC circulation through the rabbit kidney

This experiment involved 12 rabbits of both sexes, weighing 2.1 kg. After anesthesia, the kidneys were exposed, isolated and cannulated in the renal artery, ureter and sometimes in the vein as well. The kidney were perfused through the renal artery with Krebs-Henseleit solution, which were then filtered to be free of particles, gased with 95% O2-5% CO2, and kept at 37 degrees C. We measured RBCs concentrations by means of Coulter Counter in the venous outflow collected, and plotted them against the volume perfused. Using 2 different flow rates, 9 ml/min (group I) and 19 ml/min (group II), we found that the RBCs decreased in a multiexponential decay fashion and a biophysical model for each flow rate was constructed. These models indicated that there were more cell stores (2.20 x 10(10)) in the fast compartment of group II than in group I (1.72 x 10(10)). This difference is not statistically significant, but certainly coincides with urine flow collected from ureter cannula during perfusion. Our present data clearly suggest that in order to clear 99% blood cells out of 10-12 gm rabbit kidneys, at least 3-6 ml of cell free perfusate is required while clearing the whole blood cells out of human kidneys (200-240 gm) may need 600 ml or more. Thus, we recommend that at least 600 ml of perfusate should be used to clear most of the blood cells in the renal vasculature before renal transplantation is performed.

Morphological evidence of pulmonary vascular leakage through gaps observed with casting methods and S.E.M

We have used selective casting methods to separate pulmonary elastin from vascular elastin in the lungs of rabbits, dogs and pigs. The lungs are digested with 0.1 N NaOH at 75 degrees C for 24 approximately 48 hours with frequent turning as the lungs are filled with air to about 80% of the vital capacity prior to the casting which is done at pressure of 20 approximately 50 mmHg. After vascular injections, we saw many small globular bits of casting material well separated from cast vessels and lying in the pulmonary elastin. Surface forces should make the casting material creep along the vessels even if they are not completely filled, so that the spherical shape is the one expected if the case is extruded into the parenchymal space and the air space. We conclude that this suggests that the pulmonary circulation is partially and temporarily 'open' as seen in the spleen and some other organs, rather than a completely 'closed' one as is generally accepted. At least some of these extravasations may be associated with lymphatics, although we have not proved this.

Planar optical implementation of crossover interconnects

We propose a planar optical configuration for implementation of crossover interconnects. The planar overlay allows two-dimensional pixel arrays located on a wafer-scale integrated circuit to be interconnected in a compact and vibrationally robust configuration. By using an acute-angle microprism array with apex angles of 70.52 deg fabricated on a silicon substrate, we show the experimental result of the crossover interconnections. Some practical limits of the planar optical crossover interconnections are also discussed.

Effect of peripheral nerve stimulation on the dorsal horn cell activity in cats with cutaneous inflammation

There are some reports showing that an experience of long-enduring pain causes a change in the pain transmission system, suggesting a plastic nature of the nociceptive system. However, most of the studies concerning the analgesic effect of peripheral nerve stimulation dealt with normal animal or human subjects. So, the present study was undertaken to investigate the effect of peripheral nerve stimulation on the dorsal horn cell activity using a tonic pain model, which was made by producing a cutaneous inflammation. The main results are summarized as follows. 1) The evoked activity by electrical or natural stimulation as well as spontaneous activity was enhanced, and the receptive field size was also expanded by the inflammation. 2) Peripheral nerve conditioning stimulation reduced the C-response of the dorsal horn cell in the normal and inflamed group, and the degree of inhibition between the two groups showed no significant difference. 3) Inhibition of the C-response of the dorsal horn cells by peripheral conditioning stimulation was completely reversed by naloxone in the inflamed group whereas there was a partial block in the normal group.

Modulation of acute morphine tolerance by corticotropin- releasing factor and dynorphin a in the mouse spinal cord

Previously, we have demonstrated that intrathecally (i.t.) administered corticotropin-releasing factor (CRF) in mice produces stimulus-specific antinociception and modulation of morphine-induced antinociception by mechanisms involving spinal kappa opioid receptors. Recently, we also have found that CRF releases immunoreactive dynorphin A, a putative endogenous kappa opioid receptor agonist, from superfused mice spinal cords in vitro. Dynorphin A administered intracerebroventricularlly (i.c.v.) to mice has been shown to modulate the expression of morphine tolerance. In the present study, the possible modulatory effects of i.t. administered CRF as well as dynorphin A on morphine tolerance were studied in an acute tolerance model. Subcutaneous administration of 100 mg/kg of morphine sulfate (MS) to mice caused an acute tolerance to morphine-induced antinociception. The antinociceptive ED50 of MS was increased from 4.4 mg/kg (naive mice) to 17.9 mg/kg (4 hours after the injection of 100 mg/kg MS). To study the modulatory effects of spinally administered CRF and dynorphin A on the expression of morphine tolerance, CRF and dynorphin A were injected i.t. at 15 min and 5 min, respectively, before testing the tolerant mice by the tail-flick assay. The antinociceptive ED50 of MS in tolerant mice was decreased to 8.8 mg/kg and 7.1 mg/kg, respectively, after i.t. administration of CRF (0.1 nmol) and dynorphin A (0.2 nmol). In contrast, 0.5 nmol of alpha-helical CRF (9-41), a CRF antagonist and 0.4 nmol of norbinaltorphimine, a highly selective kappa opioid receptor antagonist, when administered i.t. at 15 min before the tail-flick test in tolerant mice, increased the antinociceptive ED50 of MS to 56.6 mg/kg and 88.8 mg/kg, respectively. These data confirmed the modulatory effect of dynorphin A on morphine tolerance and suggested that CRF, which releases dynorphin A in several central nervous system regions, also plays a modulatory role in the expression of morphine tolerance.

Use of a persistent photoconductive array in the learning of an optoelectronic neural processor

Persistent photoconductors of npnp doping-modulated amorphous silicon multilayers are investigated for the implementation of variable analog and nonvolatile synaptic weights of an optoelectronic neural processor. The time dependence of the persistent photoconductance of the amorphous silicon multilayers is characterized in experiments. The learning performance of an optical pattern classifier with the persistent photoconductive array is analyzed by computer simulations.

Internal intensity standards for heme protein UV resonance Raman studies: excitation profiles of cacodylic acid and sodium selenate

We examine the utility of SO4(2-), ClO4-, cacodylic acid, and SeO4(2-) as internal intensity standards for Raman spectral measurements of protein structure. We find that 0.1 M SO4(2-) and ClO4- perturb the protein tertiary structure of aquomethemoglobin (met-Hb) and its fluoride (met-HbF) and azide (met-HbN3) complexes. Changes occur for the tryptophan near-UV absorption bands, the iron spin state is altered, and the fluoride ligand affinity decreases. Concentrations of ClO4- and SO4(2-) as low as 0.1 M suppress the met-HbF quaternary R----T transition induced by the allosteric effector inositol hexaphosphate (IHP). In contrast, similar concentrations of cacodylic acid and SeO4(2-) show little effect on the hemoglobin tertiary or quaternary protein structures or upon the R----T transition induced by IHP. We measure the Raman cross sections of cacodylic acid and SeO4(2-) between 218 and 514.5 nm and find that for UV excitation they are ca. 5-fold larger than ClO4- or SO4(2-). Thus, cacodylic acid and selenate can be used at lower concentrations. Cacodylic acid and SeO4(2-) are superior Raman internal intensity standards for protein structural studies.

Optical implementation of a quadratic associative memory by using the polarization-encoding process

As a higher-order associative memory of a neural network, the quadratic associative memory is implemented holographically by using the polarization-encoding process. The use of polarization encoding to represent sign in the quadratic associative memory tensor is made by twisted nematic liquid-crystal light modulators. Experimental results of retrieving the stored objects from an incomplete input are presented.

Heterogeneous electron transfer of cytochrome c facilitated by polypyrrole and methylene blue polypyrrole film modified electrodes

Polypyrrole and methylene blue incorporated polypyrrole thin-film modified electrodes were prepared by the electrochemical polymerization method. These modified electrodes may facilitate heterogeneous electron transfer of cytochrome c with high electrocatalytic activity and good stability. Optical thin-layer spectroelectrochemical techniques were used to determine the characteristics of these electrochemical processes such as formal redox potential (E0), electron transfer number (n), and the apparent rate constant (ks.h0).

A comparison of the size of fenestrations in the internal elastic lamina of young and old porcine aortas as seen with the scanning electron microscope

The size of the fenestrations (windows) in the internal elastic lamina (IEL) of arteries may be important in the functioning of the blood vessel wall. The fenestrations are filled with collagen, muscle, and (or) ground substance, which must be removed to make the fenestration visible with the scanning electron microscope. All of the nonelastic components are removed with a hot alkali solution. Our experiments were designed to compare the fenestration size in the IEL of the thoracic aorta of young (6-8 weeks) and old (6-9 months) pigs. A protocol for digestion of young pig tissue was developed and showed that fresh young aortas should be digested in 0.1 M NaOH at 75 degrees C for 2 h and fixed tissue should be digested for 5 h. The average area of the fenestrations for young pig thoracic aortas digested for 2 h was 1.8 +/- 0.29 (SE) microns 2 and for the old pig aortas digested for 2 h was 1.7 +/- 0.11 (SE) microns 2. These values were not significantly different (p greater than 0.05), but the IEL from young pigs appeared rougher than the previously reported smooth IEL of the adult pigs.

Percutaneous transcatheteral biliary biopsy (PTBB)--a report of two cases

In two patients with obstructive jaundice, percutaneous transhepatic cholangiography (PTC) and percutaneous transhepatic biliary drainage (PTBD) were performed. During PTBD, the percutaneous transcatheteral biliary biopsy (PTBB) with the biopsy forceps of the gastrofiberscope was performed through the biliary stent catheter. Biopsy specimens were successfully obtained and histopathologic findings were satisfactory in both cases.

Properties of holographic associative memory prepared by the polarization encoding process

A new holographic associative memory (HAM) using optical polarization is proposed. Picture elements (pixels) of binary objects are encoded with two mutually perpendicular states of linear polarization, and they are stored in the HAM using a lensless diffuser system. Experimental results of recognizing various inputs are presented. Analytical expressions about the present HAM are derived, and results of computer simulation are also presented.

Arterial elastin as seen with scanning electron microscopy: a review

All large arteries contain elastin, collagen, and muscle which can be seen with light microscopy and transmission electron microscopy. Elastin forms an internal elastic lamina (IEL) in all arteries, but also forms multiple fenestrated sheets in the media of the aorta and other large arteries. The fenestrations in the media are larger than those in the IEL. The adventitial elastin is more fibrous and often contains tubular elastin surrounding vasa vasorum when prepared by removing all non-elastin by placing the aorta in 0.1 N NaOH at 70-75 degrees C for five hours. The fenestrations are larger near branches and in an experimentally created poststenotic dilatation. Atherosclerosis appears associated with both new elastin formation in early atherosclerosis and elastolysis in late disease.

Brain iron in patients with Parkinson disease: MR visualization using gradient modification

In patients with Parkinson disease, improved visualization of brain iron on a mid-field-strength magnet can be obtained with T2-weighted images and elimination of phase-encoding artifacts. A long echo delay time accentuates the loss of signal from brain iron. However, the long pulse sequence creates phase-encoding artifacts from CSF pulsations at the level of the basal ganglia. These artifacts are eliminated and resolving power increased with additional pulsing in the slice-selective and read gradients. Elimination of motion artifacts enhances visualization of brain iron in three ways: (1) extrapyramidal nuclei containing iron have better definition, (2) abnormalities are better identified, and (3) pseudolesions disappear. Our findings suggest there is significant improvement in the resolving power of brain iron on MR scans made with a mid-field-strength scanner when gradient modification is used.

Trial of specific antigen-mediated leukocyte adherence inhibition test in patients with chronic active hepatitis and hepatitis B carrier

In the pathogenesis of chronic active hepatitis, the importance of cell mediated immunity (CMI) has been emphasized. Leukocyte adherence inhibition (LAI) assay, which is one of the methods for analysis of the reaction of CMI, has been used to analysie the CMI of cancer patients.

The authors tried the specific antigen-mediated LAI assay in 40 patients with chronic active hepatitis, 19 patients carriers of hepatitis B virus, and in the 5 persons who have no anti-HBs in spite of receiving vaccination against HBV, and these were compared with 7 normal control subjects who had been exposed to hepatitis B virus previously.

The results were as follows: The NAI was 52.4±14 (mean ± standard deviation) in 7 normal control subjects who had been exposed to hepatitis B virus previously. The NAI was 20.6 ± 11 (mean ± standard deviation) in 40 patients with chronic active hepatitis. The value was significantly lower than that of the normal control group (P<0.001). The NAI was 49.7±17.8 (mean ± standard deviation) in 19 patients carriers of hepatitis B virus. The value was not significantly different from that of the normal control group (P>0.05). The NAI was 25.1±11 (mean ± standard deviation) in 5 persons who have no anti-HBs in spite of receiving vaccination against HBV. The value was significantly lower than that of the normal control group (P<0.05). In patients with chronic active hepatitis and hepatitis B virus carriers, we checked the LAI assay serially. The value of NAI was increased according to the improvement of clinical symptoms and normalization of transaminase, but the value of NAI was decreased according to the worsening of clinical symptoms and elevation of transaminase.