Showing papers by "Chonbuk National University published in 1995"

Intrinsic epileptogenicity of human dysplastic cortex as suggested by corticography and surgical results

Abstract: Cortical dysplastic lesions (CDyLs) are often associated with severe partial epilepsies. We describe the electrographic counterpart of this high degree of epileptogenicity, manifested by continuous or frequent rhythmic epileptogenic discharges recorded directly from CDyLs during intraoperative electrocorticography (ECoG). These ictal or continuous epileptogenic discharges (I/CEDs) assumed one of the following three patterns: (1) repetitive electrographic seizures, (2) repetitive bursting discharges, or (3) continuous or quasicontinuous rhythmic spiking. One or more of these patterns were present in 23 of 34 patients (67%) with intractable partial epilepsy associated with CDyLs, and in only 1 of 40 patients (2.5%) with intractable partial epilepsy associated with other types of structural lesions. I/CEDs were usually spatially restricted, thus contrasting with the more widespread interictal ECoG epileptic activity, and tended to colocalize with the magnetic resonance imaging-defined lesion. Completeness of excision of cortical tissue displaying I/CEDs correlated positively with surgical outcome in patients with medically intractable seizures; i.e., three-fourths of the patients in whom it was entirely excised had favorable surgical outcome; in contrast, uniformly poor outcome was observed in those patients in whom areas containing I/CEDs remained in situ. We conclude that CDyLs are highly and intrinsically epileptogenic, and that intraoperative ECoG identification of this intrinsically epileptogenic dysplastic cortical tissue is crucial to decide the extent of excision for best seizure control.

Improvement in hydrogen storage characteristics of magnesium by mechanical alloying with nickel

Abstract: The hydriding and dehydriding kinetics of Mg are reviewed. It is reported that the hydriding and dehydriding reactions of Mg are nucleation-controlled under certain conditions and progress by a mechanism of nucleation and growth, and that the hydriding rates of Mg are controlled by the diffusion of hydrogen through a growing Mg hydride layer.

Nitric oxide synthesis contributes to il-2-induced antitumor responses against intraperitoneal meth a tumor

Abstract: IL-2 therapy is a potent inductive stimulus for nitric oxide (NO.) synthesis in mice and humans. It is not yet clear whether NO. can contribute to IL-2-induced therapeutic responses. The murine skin cancer Meth A is relatively resistant to lymphokine-activated killer (LAK) cell killing, allowing evaluation of the role of IL-2-induced NO. synthesis in vivo, without contribution by LAK cells. Subcutaneous IL-2 treatment of mice bearing i.p. Meth A tumor increased nitrite production by cells derived from ascites (63 +/- 14 microM vs 3.2 +/- 1.5 microM in untreated controls). N omega-monomethyl-L-arginine (MLA), NO. synthase inhibitor, prevented this increase. NO. production correlated in an inverse fashion with tumor cell proliferation in vitro. Evidence for IL-2-induced heme nitrosylation was demonstrated in tumor cells by electron paramagnetic resonance spectroscopy. By immunomagnetic depletion experiments, macrophages were implicated as a major source of NO. synthesis. Cytologic and flow-cytometric evaluation revealed that IL-2 treatment resulted in enhanced lymphocyte and macrophage recruitment into malignant ascites, and decreases in tumor cell recovery. MLA administration further increased host cell recovery. Subcutaneous IL-2 therapy increased urinary nitrate excretion up to eightfold in mice, and appeared to produce a significant survival advantage that was prevented by MLA administration.

High speed pattern matching for a fast Huffman decoder

Abstract: The fast Huffman decoding algorithm has been used in JPEG, MPEG and image data compression standards, etc. And code compression is a key element in high speed digital data transport. A major compression is performed by converting the fixed-length codes to variable-length codes through an entropy coding scheme. Huffman coding combined with run-length coding is shown to be a very efficient coding scheme. To speed up the process of search for a symbol in a Huffman tree and to reduce the memory size we have proposed a tree clustering and a pattern matching algorithm to avoid high sparsity of the tree. The method is shown to be very efficient in memory size and fast searching for the symbol. For an experimental video data with Huffman codes extended up to 16 bits in length, i.e. it is used for the standard JPEG, the result of experiments show that the proposed algorithm has a very high speed and performance. The design of the decoder is carried out using silicon-gate CMOS process. >

Surfactant treatment at birth reduces lung vascular injury and edema in preterm lambs.

Abstract: To study the effect of surfactant administration on fluid balance in the premature lung, we measured pulmonary vascular pressures, lung lymph and pleural liquid flow, and concentrations of protein in lymph, pleural liquid, and plasma before and after birth in 12 chronically catheterized preterm lambs (127-128 d gestation) treated with either placebo or surfactant just before surgical delivery. Eight lambs received intrapulmonary saline (placebo), and four lambs received surfactant; all lambs were mechanically ventilated with O2 for 8 h after birth. In control lambs, lung lymph and pleural liquid flow increased from 2.7 +/- 0.4 mL/h during the 2-4 h before birth to 9.2 +/- 2.1 mL/h by 6-8 h after birth; lymph and pleural space protein drainage increased from 58 +/- 7 mg/h during the 2-4 h before birth to 134 +/- 25 mg/h by 6-8 h after birth. In lambs treated with surfactant, there was no significant increase in lymph and pleural liquid flow after birth (before birth, 2.3 +/- 0.3 mL/h; 6-8 h after birth, 3.4 +/- 0.9 mL/h); likewise, lymph and pleural space protein drainage did not change after birth (before birth, 54 +/- 6 mg/h; 6-8 h after birth, 50 +/- 8 mg/h). Postmortem extravascular lung water was significantly less in lambs treated with surfactant compared with control lambs (control, 6.5 +/- 0.3 g/g dry lung; surfactant-treated, 5.0 +/- 0.2 g/g dry lung).(ABSTRACT TRUNCATED AT 250 WORDS)

Renal Function and Hemodynamic Study in Obese Zucker Rats

Abstract: OBJECTIVES To investigate the renal function and hemodynamic changes in obesity and hyperinsulinemia which are characteristics of type II diabetes. METHODS Studies were carried out in two groups of female Zucker rats. Group 1 rats were obese Zucker rats with hereditary insulin resistance. Group 2 rats were lean Zucker rats and served as controls. In comparison with lean Zucker rats, obese Zucker rats exhibited hyperinsulinemia but normoglycemia. Micropuncture studies and morphologic studies were performed in these rats. RESULTS Functional studies showed that obese Zucker rats exhibited increases in kidney weight and GFR(obese Zucker, 1.23 +/- .07)ml/min; lean Zucker, 0.93 +/- .03ml/min). Micropuncture studies revealed that the increase in GFR in obese Zucker rats was attributable to the increases in the single nephron plasma flow rate and glomerular transcapillary hydraulic pressure. The glomerular ultrafiltration coefficient was the same in both groups. Morphologic studies revealed that the increase in GFR in obese Zucker rats was associated with an increase in glomerular volume. CONCLUSIONS These results suggest that obesity and hyperinsulinemia, which are the characteristics of type II diabetes, can be associated with glomerular hyperfiltration and glomerular capillary hypertension.

A high speed Reed-Solomon decoder

Abstract: The Reed Solomon code (RS code) has been widely employed in digital audio/video equipment owing to its excellent capability for correcting burst errors and relatively easy implementation. The authors propose an architecture for an error correction circuit suitable for high-rate data decoding of the Reed-Solomon code. The circuit has encoder and decoder functions by 2 symbol random error correction as well as 4 symbol erasure correction. 23 Mbyte/s rate of data decoding is sufficient for compressed video signals of high-definition as well as those of standard-definition TVs.

Ca2+-dependent and -independent mechanisms of ischaemia-evoked release of 3h-dopamine from rat striatal slices

Abstract: 1. Ischaemia was induced by 5 min of deprivation of glucose and an additional 5 min of deprivation of glucose and oxygen from Mg(2+)-free artificial cerebrospinal fluid in vitro. 2. During the ischaemic period, 11 +/- 1.5% of the total [3H]-dopamine ([3H]-DA) was released into the incubation medium. 3. Ischaemia-evoked release of [3H]-DA from striatal slices was attenuated by tetrodotoxin (TTX), MgSO4, dizocilpine, ketamine, 6,7-dinitroquinoxaline-2,3-dione (DNQX) or carbetapentane. 4. Release of [3H]-DA was attenuated by verapamil, omega-conotoxin GVIA and dantrolene. 5. Nomifensin inhibited the ischaemia-induced release of [3H]-DA. 6. Omission of Ca(2+) from incubation media potentiated ischaemia-evoked [3H]-DA release. The inhibitory effect of nomifensin was potentiated in Ca(2+)-free incubation media. 7. These results suggest that ischaemia induces release of [3H]-DA by dual mechanisms; one is Ca(2+)-dependent exocytosis and the other is reversal of transporter.

A study of joining Ag/BSCCO superconducting tapes

Abstract: A superconducting joint between Ag/BSCCO tapes has been fabricated by using a combination of etching, pressing and annealing techniques. The joined area, fabricated with a load of 10 ton, showed 80% current carrying capacity of the tapes without join-interface. I c of the joined area in the low-field region drops more quickly with magnetic field than the unjoined area. It is considered that the lower magnetic resistivity of I c and I c degradation in the joined area resulted from the heterogeneous deformation in the joined area. The joined area was mechanically weak.

Self-expandable metallic stents in high-risk patients with benign prostatic hyperplasia: Long-term follow-up

Abstract: PURPOSE: To evaluate the long-term clinical utility of self-expandable metallic Z stents in benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: Under fluoroscopic guidance, 14 multiple-connected Z stents (10 mm in diameter fully expanded, 30-60 mm in length) were placed in 13 patients with bladder obstruction from BPH and high operative risks. The stents were placed in the prostatic urethra with 2-20-mm protrusion into the urinary bladder in six patients (group A) and entirely within the prostatic urethra in seven patients (group B). RESULTS: Eleven of 13 patients could void immediately, and the other two patients with atonic bladder voided within 8 weeks. Maximum urine flow rates just after stent placement were 8-27 mL/sec. Two patients died of unrelated causes within 2 months. During the follow-up period (mean, 37 months) in the other 11 patients, all patients in group A but none in group B underwent surgery owing to stone formation where the stent protruded into the bladder. CONCLUSION: Expandab...

Nucleotide sequence of genomic DNA encoding the potato beta-1,3-glucanase.

Abstract: Molecular and biochemical studies of plant defense responses have identified severa1 molecules such as salicylic acid, systemin, jasmonate, and ethylene as potential systemic signals involved in systemic acquired resistance to pathogens and pests. Among them, ethylene is known to be associated with induction of chitinase and P-1,3-glucanase, which are present in many higher plants (Boller et al., 1983). Both enzymes have been implicated in defense reactions of plants against potential pathogens (Abeles et al., 1971; Boller et al., 1983). In many plants, chitinase and p-1, 3-glucanase rapidly accumulate following pathogen attack, after elicitor treatment, and in response to the plant stress hormone ethylene (Boller, 1985). The substrates for chitinase and P-1,3-glucanase, chitin and /3-1,3-glucan, respectively, are major components of the cell walls of many fungi (Wessels and Sietsma, 1981). It has been shown that chitinase and /3-1,3-glucanase can degrade isolated fungal cell walls (Mauch et al., 1988). In addition, physiological concentrations of chitinase and P-1,3-glucanase effectively inhibit growth of many potentially pathogenic fungi (Schlumbaum et al., 1986; Mauch et al., 1988). As a result, chitinase and P-1,3-glucanase appear to be a part of the inducible defense response of higher plants (Mauch and Staehelin, 1989). A genomic clone for potato /3-1,3-glucanase was isolated to study the regulatory expression mechanism of the plant gene. A genomic DNA library was constructed with total DNA isolated from potato (Solanum tuberosum L. cv Sumi) leaves. A genomic DNA clone ( AGlcl) for P-13-glucanase was isolated by plaque hybridization of the library using a cDNA clone for tobacco P-1,3-glucanase as a probe. Southern blot analysis showed that a genomic fragment of 1.6 kb harbored the P-l,3glucanase gene of potato. The structure of the genomic clone was determined by nucleotide sequencing, which, together with the result of RNA mapping with nuclease S1, shows that the P-l,3-glucanase gene of potato consists of two exons and one intron, 1269 bp, and encodes 193 amino acids (Table I).

Electronic structure of vacancies in amorphous silicon.

Abstract: The electronic structures of vacancies in amorphous silicon are studied by a tight-binding total-energy-minimization scheme. The most salient feature in the electronic structure is that deep gap states originating from the vacancies disappear in amorphous silicon while sustaining the vacant volume in most cases, unlike the vacancies in crystalline silicon. The origin of the disappearance of the deep gap states is explained by the relaxation of the neighboring atoms near the vacancy to enhance the strong ${\mathit{p}}_{\mathrm{\ensuremath{\pi}}}$ bonding character which gives large bonding-antibonding splitting, and ${\mathit{sp}}^{2}$+p bonding character where p states mostly contribute to the conduction bands.

Pipelined lattice WDF design for wideband filters

Abstract: Wideband highpass filters are widely used in applications such as wireless codec design or ECG signal processing. It is well-known that wideband digital filters suffer from large sensitivity and roundoff noise. In this letter, an efficient pipelined WDF (Wave Digital Filter) design method for wideband filters is proposed. Using one design example, it is shown that the hardware cost can be reduced by 45% by using the proposed approach instead of conventional approaches. >

Charge distributions in PC/SAN/PCL polymer blends

Abstract: The formation of space charge in polycarbonate (PC)/poly (styrene-co-acrylonitrile) (SAN) blends containing poly (/spl epsiv/-caprolactone) (PCL) as a compatibilizer for improving the miscibility, has been studied by measuring spatial charge distributions. It is found that the miscibility of PC/SAN blends is improved as the PCL content increases. The amount of charge accumulated in the blends decreases when the PCL content increases to 15% by weight and then increases when the PCL content is >15% wt. The decrease of charge at the PCL content 15% wt was attributed to the trapping of charge at the amorphous and crystalline phases of PC and PCL. >

Oocyst production and immunogenicity of Cryptosporidium baileyi in chickens and mallards.

Abstract: Two-day-old chickens and mallards were orally inoculated with one of 5 doses varying from 2 x 10(2) to 2 x 10(6) of C. baileyi oocysts per individual. Generally, the more oocysts inoculated were, the longer the patent periods were, and the more oocysts shedding were. Meanwhile increasing the inoculative dose, the prepatent periods were shortened except that mallards inoculated with 2 x 10(2) and 2 x 10(3) oocysts failed to produce the oocysts. The more parasites involving oocysts appeared from the chicken in comparison to the mallard. In the chickens challenged with a single dose of 2 x 10(6) oocysts, a small number of oocysts were detected from feces on days 4-14 after challenge infection (ACI) in all of carrageenan administered groups and in the control groups inoculated with 2 x 10(2) and 2 x 10(3) oocysts. In the mallards, a few oocysts were also recognized on days 5-15 ACI in all of carrageenan treated groups and in the control groups inoculated with 2 x 10(2), 2 x 10(3) and 2 x 10(4) oocysts. Just prior to challenge infection, phagocytic activity of peritoneal macrophages (Mo) and the number of peripheral Mo in both birds were significantly decreased in the carrageenan treated groups as compared to the control groups. Mild challenge infection in both birds denoted that the immunogenicity of C. baileyi to the birds was very strong, despite Mo blocker carrageenan administration.

Oocyst production and immunogenicity of Cryptosporidium muris (strain MCR) in mice

Abstract: Three-week-old ICR SPF mice were orally inoculated with one of 5 doses ranging from 2 x 10(2) to 2 x 10(6) oocysts of Cryptosporidium muris (strain MCR) per mouse. Oocyst inoculation was directly proportional to the amount of oocysts shed and was inversely proportional to the period required for peak oocyst production and to the prepatent period. Peak oocyst production occurred between fifteen and thirty-one days with a patent period from 61 to 64 days. Three days after all mice stopped shedding oocysts, they were orally challenged with a single dose of 2 x 10(6) oocysts of the same species. Marked seroconversion for IgG antibody accompanied recovery from mice inoculated with 5 x 10(5) oocysts. Mice administered with carrageenan excreted a small number of oocysts for 49.0 days on the average after challenge inoculation (ACI) and control mice for 14.2 days in a dose-independent fashion. Just before challenge infection, phagocytic activity of peritoneal macrophages (M phi) and the number of peripheral M phi were dramatically decreased. Mild challenge infection implies that the immunogenicity of C. muris (strain MCR) is very strong, despite M phi blocker carrageenan administration.

KR-30450, a newly synthesized benzopyran derivative, activates the cardiac ATP-sensitive K+ channel.

Abstract: KR-30450 (2-(2"(1",3"-dioxolone)-2-methyl-4-(2'-oxo-1'-pyrrollidinyl) -6- nitro-2H-1-benzopyren) is a newly synthesized benzopyran derivative. We examined the effect of KR-30450 on the action potential duration of isolated rat papillary muscle and on the ATP-sensitive K+ channel (KATP) activity in single rat ventricular myocytes with 3 M KCl-filled conventional microelectrode and patch clamp techniques. KR-30450 (10(-7) approximately 10(-5) M) reduced the action potential duration in a concentration-dependent manner and this was inhibited by 3 microM glibenclamide, suggesting that KATP was involved. In cell-attached patches, KR-30450 (10(-5) M) in the pipette activated the KATP which was closed by 3 microM glibenclamide. In inside-out patches, the effects of KR-30450 on KATP activity were examined before and after run-down of the channel. Before run-down, KR-30450 increased the KATP activity only in the presence of ATP and shifted the [ATP]i-KATP activity relationship to the right. After run-down, KR-30450 did not affect the KATP activity either in the presence or absence of 3 mM UDP, but increased the UDP-induced KATP activity in the presence of 1 mM ATP-gamma-S. From these results, we conclude that KR-30450 antagonizes the inhibitory effect of ATP on the KATP in a competitive manner. These effects of KR-30450 are similar to those of ER-001533 and HOE-234, but different from those of pinacidil and lemakalim.

Immunohistochemical localization of NAD glycohydrolase in human and rabbit tissues

Abstract: NAD glycohydrolase (NADase) is present in many organisms from bacteria to mammals. In any given organism, this enzyme is ubiquitous in many tissues. However, its precise localization and its physiological significance have not been defined. We have determined the distribution of NADase in normal human and rabbit tissues by immunoblotting and immunohistochemistry, using a polyclonal antibody raised in goats. Immunoblot analyses revealed that NADase was highly expressed in the heart, lung, stomach, and liver tissues of the rabbit. From immunohistochemical studies of NADase, high concentrations in both human and rabbit tissues were found in hepatocytes and sinusoidal lining cells, sinus histiocytes of the lymph node, spleen and thymus, glomerular capillary endothelial cells of the kidney, cardiac muscle, endothelium of blood vessles, and erythrocytes.

Assessing quality of life for the measurement of outcome after epilepsy surgery.

Abstract: Epilepsy impacts on a person's life in various aspects not only physical but also psychological and social. Quality of life in patients with epilepsy may be impaired by seizures, side effects of medications and psychological problems.' Traditionally the outcome after epilepsy surgery has focused on changes in seizure frequency from presurgical measures. However, the reduction of seizure frequency itself cannot reflect the improvement of emotional and social well-being in epileptic patients. The ultimate goal of surgery is to improve the quality of life. Measurement of outcome should be, therefore, comprehensive, including all dimensions of health, such as mental, social and physical.* We evaluated the quality of life in patients with epilepsy and compared the results with normal subjects to investigate the functional problems of patients with epilepsy, and we also assessed the status of preand post-surgical quality of life to define the outcome of surgical treatment.

Mechanism of silicon etching in HF-KMnO4-H2O solution

Abstract: The etching reaction of silicon in HF-KMnO4-H2O mixed solution has been studied under various experimental conditions. The etch rates were measured as a function of agitation speed, HF and KMnO4 concentrations, and etching temperature and time. A comprehensive mechanism for the silicon etching and insoluble solid-phase film (K2SiF6) formation has been proposed. The holes formed at silicon surface accelerated not only the etch rate of silicon but also the formation rate of K2SiF6. With the increase of hole concentration at lower HF concentrations the etch rates decreased because of the deposition of K2SiF6 on etched silicon surface. Under the condition of sufficiently high HF concentration, the rate increased with the increase of hole formation and the formation of holes at silicon surface was the rate limiting step of the silicon etching reaction in HF-KMnO4-H2O solution. High HF concentration enough for dissolving K2SiF6 was apparently essential to obtain high etch rate in the silicon etching reaction.

Taxonomical approach to scabies mites of human and animals and their prevalence in Korea

Abstract: Three types, hitherto commonly known as varieties of Sarcoptes scabiei (Linnaeus, 1758) were collected from scabietic patients, pigs and dogs to confirm their taxonomic status. As a result, we consider that the mites of human and pig scabies are different subspecies [S. scabiei scabiei (Linnaeus, 1758) and S. scabiei suis Megnin, 1880, respectively], and that of dog scabies is a different species, S. canis Gerlach, 1857. Infestation rate of human scabies in Korea peaked in 1981-1982 and showed nearly 10% of prevalence rate among outpatients of the dermatology clinic, but decreased dramatically during the past ten years and now lowered below 1% since 1990. On the other hand, dog scabies seems to be increasing recently.