• Title/Summary/Keyword: Detection Technique

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DISEASE DIAGNOSED AND DESCRIBED BY NIRS

  • Tsenkova, Roumiana N.
    • Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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    • 2001.06a
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    • pp.1031-1031
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    • 2001
  • The mammary gland is made up of remarkably sensitive tissue, which has the capability of producing a large volume of secretion, milk, under normal or healthy conditions. When bacteria enter the gland and establish an infection (mastitis), inflammation is initiated accompanied by an influx of white cells from the blood stream, by altered secretory function, and changes in the volume and composition of secretion. Cell numbers in milk are closely associated with inflammation and udder health. These somatic cell counts (SCC) are accepted as the international standard measurement of milk quality in dairy and for mastitis diagnosis. NIR Spectra of unhomogenized composite milk samples from 14 cows (healthy and mastitic), 7days after parturition and during the next 30 days of lactation were measured. Different multivariate analysis techniques were used to diagnose the disease at very early stage and determine how the spectral properties of milk vary with its composition and animal health. PLS model for prediction of somatic cell count (SCC) based on NIR milk spectra was made. The best accuracy of determination for the 1100-2500nm range was found using smoothed absorbance data and 10 PLS factors. The standard error of prediction for independent validation set of samples was 0.382, correlation coefficient 0.854 and the variation coefficient 7.63%. It has been found that SCC determination by NIR milk spectra was indirect and based on the related changes in milk composition. From the spectral changes, we learned that when mastitis occurred, the most significant factors that simultaneously influenced milk spectra were alteration of milk proteins and changes in ionic concentration of milk. It was consistent with the results we obtained further when applied 2DCOS. Two-dimensional correlation analysis of NIR milk spectra was done to assess the changes in milk composition, which occur when somatic cell count (SCC) levels vary. The synchronous correlation map revealed that when SCC increases, protein levels increase while water and lactose levels decrease. Results from the analysis of the asynchronous plot indicated that changes in water and fat absorptions occur before other milk components. In addition, the technique was used to assess the changes in milk during a period when SCC levels do not vary appreciably. Results indicated that milk components are in equilibrium and no appreciable change in a given component was seen with respect to another. This was found in both healthy and mastitic animals. However, milk components were found to vary with SCC content regardless of the range considered. This important finding demonstrates that 2-D correlation analysis may be used to track even subtle changes in milk composition in individual cows. To find out the right threshold for SCC when used for mastitis diagnosis at cow level, classification of milk samples was performed using soft independent modeling of class analogy (SIMCA) and different spectral data pretreatment. Two levels of SCC - 200 000 cells/$m\ell$ and 300 000 cells/$m\ell$, respectively, were set up and compared as thresholds to discriminate between healthy and mastitic cows. The best detection accuracy was found with 200 000 cells/$m\ell$ as threshold for mastitis and smoothed absorbance data: - 98% of the milk samples in the calibration set and 87% of the samples in the independent test set were correctly classified. When the spectral information was studied it was found that the successful mastitis diagnosis was based on reviling the spectral changes related to the corresponding changes in milk composition. NIRS combined with different ways of spectral data ruining can provide faster and nondestructive alternative to current methods for mastitis diagnosis and a new inside into disease understanding at molecular level.

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Survey of Beet Red Contents in Foods using TLC, HPLC (TLC, HPLC를 이용한 식품 중 비트레드 함량조사)

  • Jang, Yaung-Mi;Lee, Tal-Soo;Hong, Ki-Hyoung;Park, Sung-Kwan;Park, Sung-Kug;Kwon, Yong-Kwan;Park, Jae-Seok;Chang, Sun-Young;Hwang, Hye-Shin;Kim, Eun-Jeong;Han, Yeun-Jeong;Kim, Byung-Sub;Won, Hye-Jin
    • Journal of Food Hygiene and Safety
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    • v.20 no.4
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    • pp.244-252
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    • 2005
  • This study was performed far development of new analytical method of beet red in foods. In this study, analysis of beet red in foods has been carried out by detection of betanine and isobetanine, the main color component of beet red as indicator compounds. The qualitative analysis technique consisted of clean-up of the colors with a $C_{18}$ cartridge, separation of the colors by cellulose TLC plate using acetone:3-methyl-1-butanol:distilled water (7:7:6) as a solvent system. Also, the quantitative analysis was performed using X-terra RP at wavelength 538 nm and $0.1\%$ phosphoric acid : methanol (90:10) as a solvent. The quantitative results of beet .ed were as follows:900.22$\∼$27701.60 $\mu$g/g for 60 item in nutrient supplement food, $21.95\∼713.40{\mu}g/g$ for 30 items and N.D. for 18 items in cindy, and $155.85{\∼}505.37{\mu}g/g$ for 12 items in ice creams, $43.52\∼64.75{\mu}g/g$ for 18 items and N.D. for 54 item in sauce, N.D. for 12 items in retort food.

GENETIC ALTERATIONS OF HUMAN ORAL CANCERS USING COMPARATIVE GENOMIC HYBRIDIZATION (Comparative genomic hybridization 기법을 이용한 인체 구강암의 유전자 변화에 대한 연구)

  • Lee, Myeong-Reoyl;Shim, Kwang-Sup;Lee, Young-Soo;Woo, Soon-Seop;Kong, Gu
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.26 no.3
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    • pp.245-253
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    • 2000
  • The development and progression of oral cancer is associated with an accumulation of multiple genetic alterations through the multistep processes. Comparative genomic hybridization(CGH), newly developed cytogenetic and molecular biologic technique, has been widely accepted as a useful method to allow the detection of genetic imbalance in solid tumors and the screening for chromosome sites frequently affected by gains or losses in DNA copy number. The authors examined 19 primary oral squamous cell carcinomas using CGH to identify altered chromosome regions that might contain novel oncogenes and tumor suppressor genes. Interrelationship between these genetic aberrations detected and major oncogenes and tumor suppressor genes previously recognized in carcinogenesis of oral cancers was studied. 1. Changes in DNA copy number were detected in 14 of 19 oral cancers (78.9%, mean: 5.58, range: $3{\sim}13$). High level amplification was present in 4 cases at 9p23, $12p21.1{\sim}q13.1$, 3q and $8q24{\sim}24.3$. Fourteen cases(78.9%, mean: 3.00, range: $1{\sim}8$) showed gains of DNA copy number and 12 cases(70.5%, mean: 2.58, range: $1{\sim}9$) revealed losses of DNA copy number. 2. The most common gains were detected on 3q(52.6%), 5p(21.0%), 8q(21.0%), 9p(21.0%), and 11q(21.0%). The losses of DNA copy number were frequently occurred at 9p(36.8%), 17q(36.8%), 13q(26.3%), 4p(21.0%) and 9p(21.0%). 3. The minimal common regions of gains were repeatedly observed at $3q24{\sim}26.7$, $3q27{\sim}29$, $1q22{\sim}31$, $5p12{\sim}13.3$, $8q23{\sim}24$, and 11q13.1-13.3. The minimal common regions of losses were detected at $9q11{\sim}21.3$, 17p31, $13q22{\sim}34$, and 14p16. 4. In comparison of CGH results with tumor stages, the lower stage group showed more frequent gain at 3q, 5q, 9p, and 14q, whereas gains at 1q($1q22{\sim}31$) and 11q($11q13.1{\sim}13.3$) were mainly detected in higher stage group. The loss at $13q22{\sim}34$ was exclusively detected in higher stage. The results indicate that the most frequent genetic alterations in the development of oral cancers were gains at $3q24{\sim}26.3$, $1q22{\sim}31$, and $5p12{\sim}13.3$ and losses at $9q11{\sim}21.3$, 17p31, and 13q. It is suggested that genetic alterations manifested as gains at $3q24{\sim}26.3$, $3q27{\sim}29$, $5p12{\sim}13.3$ and 5p are associated with the early progression of oral cancer. Gains at $1q22{\sim}31$ and $11q13.1{\sim}13.3$ and loss at 13q22-34 could be involved in the late progression of oral cancers.

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Effective Detective Quantum Efficiency (eDQE) Evaluation for the Influence of Focal Spot Size and Magnification on the Digital Radiography System (X-선관 초점 크기와 확대도에 따른 디지털 일반촬영 시스템의 유효검출양자효율 평가)

  • Kim, Ye-Seul;Park, Hye-Suk;Park, Su-Jin;Kim, Hee-Joung
    • Progress in Medical Physics
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    • v.23 no.1
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    • pp.26-32
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    • 2012
  • The magnification technique has recently become popular in bone radiography, mammography and other diagnostic examination. However, because of the finite size of X-ray focal spot, the magnification influences various imaging properties with resolution, noise and contrast. The purpose of study is to investigate the influence of magnification and focal spot size on digital imaging system using eDQE (effective detective quantum efficiency). Effective DQE is a metric reflecting overall system response including focal spot blur, magnification, scatter and grid response. The adult chest phantom employed in the Food and Drug Administration (FDA) was used to derive eDQE from eMTF (effective modulation transfer function), eNPS (effective noise power spectrum), scatter fraction and transmission fraction. According to results, spatial frequencies that eMTF is 10% with the magnification factor of 1.2, 1.4, 1.6, 1.8 and 2.0 are 2.76, 2.21, 1.78, 1.49 and 1.26 lp/mm respectively using small focal spot. The spatial frequencies that eMTF is 10% with the magnification factor of 1.2, 1.4, 1.6, 1.8 and 2.0 are 2.21, 1.66, 1.25, 0.93 and 0.73 lp/mm respectively using large focal spot. The eMTFs and eDQEs decreases with increasing magnification factor. Although there are no significant differences with focal spot size on eDQE (0), the eDQEs drops more sharply with large focal spot than small focal spot. The magnification imaging can enlarge the small size lesion and improve the contrast due to decrease of effective noise and scatter with air-gap effect. The enlargement of the image size can be helpful for visual detection of small image. However, focal spot blurring caused by finite size of focal spot shows more significant impact on spatial resolution than the improvement of other metrics resulted by magnification effect. Based on these results, appropriate magnification factor and focal spot size should be established to perform magnification imaging with digital radiography system.

($P16^{ink4}$ Methylation in Squamous Cell Carcinoma of the Oral Cavity. (구강 편평세포암종에서 $P16^{ink4}$ 유전자의 Methylation에 대한 연구)

  • Kang, Gin-Won;Kim, Kyung-Wook;Lyu, Jin-Woo;Kim, Chang-Jin
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.22 no.2
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    • pp.164-173
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    • 2000
  • The p16 protein is a cyclin dependent kinase inhibitor that inhibits cell cycle progression from $G_1$ phase to S phase in cell cycle. Many p16 gene mutations have been noted in many cancer-cell lines and in some primary cancers, and alterations of p16 gene function by DNA methylation have been noticed in various kinds of cancer tissues and cell-lines. There have been a large body of literature has accumulated indicating that abnormal patterns of DNA methylation (both hypomethylation and hypermethylation) occur in a wide variety of human neoplasma and that these aberrations of DNA methylation may play an important epigenetic role in the development and progression of neoplasia. DNA methylation is a part of the inheritable epigenetic system that influences expression or silencing of genes necessary for normal differentiation and proliferation. Gene activity may be silenced by methylation of up steream regulatory regions. Reactivation is associated with demethylation. Although evidence or a high incidence of p16 alterations in a variety of cell lines and primary tumors has been reported, that has been contested by other investigators. The precise mechanisms by which abnormal methylation might contribute to carcinogenesis are still not fully elucidated, but conceivably could involve the modulation of oncogene and other important regulatory gene expression, in addition to creating areas of genetic instability, thus predisposing to mutational events causing neoplasia. There have been many variable results of studies of head and neck squamous cell carcinoma(HNSCC). This investigation was studied on 13 primary HNSCC for p16 gene status by protein expression in immunohistochemistry, and DNA genetic/epigenetic analyzed to determine the incidence, the mechanisms, and the potential biological significance of its Inactivation. As methylation detection method of p16 gene, the methylation specific PCR(MSP) is sensitive and specific for methylation of any block of CpG sites in a CpG islands using bisulfite-modified DNA. The genomic DNA is modified by treatment with sodium bisulfate, which converts all unmethylated cytosines to uracil(thymidine). The primers designed for MSP were chosen for regions containing frequent cytosines (to distinguish unmodified from modified DNA), and CpG pairs near the 5' end of the primers (to provide maximal discrimination in the PCR between methylated and unmethylated DNA). The two strands of DNA are no longer complementary after bisulfite treatment, primers can be designed for either modified strand. In this study, 13 paraffin embedded block tissues were used, so the fragment of DNA to be amplified was intentionally small, to allow the assessment of methylation pattern in a limited region and to facilitate the application of this technique to samlples. In this 13 primary HNSCC tissues, there was no methylation of p16 promoter gene (detected by MSP and automatic sequencing). The p16 protein-specific immunohistochemical staining was performed on 13 paraffin embedded primary HNSCC tissue samples. Twelve cases among the 13 showed altered expression of p16 proteins (negative expression). In this study, The author suggested that low expression of p16 protein may play an important role in human HNSCC, and this study suggested that many kinds of genetic mechanisms including DNA methylation may play the role in carcinogenesis.

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PCA­based Waveform Classification of Rabbit Retinal Ganglion Cell Activity (주성분분석을 이용한 토끼 망막 신경절세포의 활동전위 파형 분류)

  • 진계환;조현숙;이태수;구용숙
    • Progress in Medical Physics
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    • v.14 no.4
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    • pp.211-217
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    • 2003
  • The Principal component analysis (PCA) is a well-known data analysis method that is useful in linear feature extraction and data compression. The PCA is a linear transformation that applies an orthogonal rotation to the original data, so as to maximize the retained variance. PCA is a classical technique for obtaining an optimal overall mapping of linearly dependent patterns of correlation between variables (e.g. neurons). PCA provides, in the mean-squared error sense, an optimal linear mapping of the signals which are spread across a group of variables. These signals are concentrated into the first few components, while the noise, i.e. variance which is uncorrelated across variables, is sequestered in the remaining components. PCA has been used extensively to resolve temporal patterns in neurophysiological recordings. Because the retinal signal is stochastic process, PCA can be used to identify the retinal spikes. With excised rabbit eye, retina was isolated. A piece of retina was attached with the ganglion cell side to the surface of the microelectrode array (MEA). The MEA consisted of glass plate with 60 substrate integrated and insulated golden connection lanes terminating in an 8${\times}$8 array (spacing 200 $\mu$m, electrode diameter 30 $\mu$m) in the center of the plate. The MEA 60 system was used for the recording of retinal ganglion cell activity. The action potentials of each channel were sorted by off­line analysis tool. Spikes were detected with a threshold criterion and sorted according to their principal component composition. The first (PC1) and second principal component values (PC2) were calculated using all the waveforms of the each channel and all n time points in the waveform, where several clusters could be separated clearly in two dimension. We verified that PCA-based waveform detection was effective as an initial approach for spike sorting method.

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Immunization Effect on Naegleria fowleyi Infection in Splenectomized Mice (비장절제 마우스에서 Naegleria fowleri 감염에 대한 면역효과)

  • Han, Gwang-Hyeop;An, Myeong-Hui;Min, Deuk-Yeong
    • Parasites, Hosts and Diseases
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    • v.26 no.1
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    • pp.39-44
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    • 1988
  • A pathogenic free-living amoeba, Naegleria fowleri, is a causative protozoan parasite of primary amebic meningoencephalitis in human and experimental animals. It is known that humoral and cellular immunity contribute as the defence mechanism of host against this organism. Recently splenectomy has been argued on its effect on host defence mechanisms. The present study was aimed to observe the enact of immunization in splenectomized mice. For immunization, $5~10{\times}10^5$ trophozoites of Naegleria fewleri o 359 were intraperitoneally inoculated once a week for two weeks to BALB/c mice, and $5~10{\times}10^4$ of ameba trophozoites were intranasally inoculated for infection after splenectomy and/or immunization. ELISA technique was applied for the detection of seum IgG antibody levels. Experimental animals were divided into 4 groups; I. splenectomized and immuniEed; ll. splenectomized only; III. immunized only; IV. not splenectomized nor immunized. The results obtained were as follows: 1. Mortality rates of splenectomized and immunized mice in group I (38.1%) and immunized only in group III (25.0%) were lower than those of not immunized mice in group II (50%) and control group, IV (46.4%). 2. Survival times of mice in group I, II, III and IV were $20.1{\pm}3.6$, $17.3{\pm}4.5$, $20.4{\pm}7.0$ and $19.6{\pm}7.6$ days respectively, and there were no significant differences between them. 3. ELISA values (absorbance at 492nm) of group I (1, $10{\pm}0.29$) and group III ($1.31{\pm}0.28$) were significantly higher than that of group IV($0.24{\pm}0.37$) at day 31 of infection (p<0.05). Conclusively, it is presumed that humoral immunity against N. fowleri may operate as ever, after immunization, even though the mouse was splenectomized.

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Developmental Genetic Analysis of Avian Primordial Germ Cells and the Application to Poultry Biotechnology

  • Kagami, H.
    • Korean Journal of Poultry Science
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    • v.28 no.2
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    • pp.135-142
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    • 2001
  • A novel sterategy has been established to determine the origin of the Primordial Germ Cells (PGCs) in avian embryos directly and the developmental fate of the PGCs for the application to Poultry biotechnology. Cells were removed from 1) the centre of area pellucida, 2) the outer of area pellucida and 3) the area opaca of the stage X blastoderm (Eyal-Giladi & Kochav, 1976). When the cells were removed from the centre of area pellucida, the mean number of circulating PGCs in blood was significantly decreased in the embryo at stage 15 (Hamburger & Hamilton, 1951) as compared to intact embryos. When the cells were replenished with donor cells, no reduction in the PGCs number was observed. The removal of cells at the outer of area pellucida or at the area opaca had no effect on the number of PGCs. In case, another set of the manipulated embryos were cultured ex vivo to the hatching and reared to the sexual maturity, the absence of germ cells and degeneration of seminiferous tubules was observed in resulting chickens derived from the blastoderm in which the cells were removed from the centre of the area pellucida. It was concluded that the avian Primordial Germ cells are originated at the center of area pellucida. Developmental ability of the cells to differentiate into somatic cells and germ cells in chimeras were analyzed. Somatic chimerism was detected as black feather attributed from donor cells. Molecular identification by use of female - specific DNA was performed. It was confirmed that the donor cells could be differentiated into chimeric body and erythrocytes. Donor cells retained the ability to differentiate into germline in chimeric gonads. More than 70% of the generated chimeras transmitted donor derived gametes to their offspring indicating that the cells at the center of area pellucida had the high ability to differentiate into germ cells. A molecular technique to identify germline chimerism has been developed by use of gene scan analysis. Strain specific DNA fragments were amplified by the method. It would be greatly contributed for the detection of germline chimerism. Mixed- sex chimeras which contained both male and female cells were produced to investigate the developmental fate of male and female cells in ovary and testes. The sex combinations of donor and recipient of the resulting chimeras were following 4 pairs; (1) chimeras (ZZ/ZZ) produced by a male donor (ZZ) and a male recipient (ZZ), (2) chimeras (ZW/ZW) produced by a female donor (ZW) and a female recipient (ZW), (3) chimeras (ZZ/ZW) Produce by a male donor (ZZ) and a female recipient (ZW), (4) chimeras (ZW/ZZ) produced by a female donor (ZW) and a male recipient (ZZ). It was found that genetically male avian germ cells could differentiate into functional ova and that genetically female germ cells can differentiate into functional spermatozoa in the gonad of the mixed- sex chimeras. An ability for introduction of exogenous DNA into the PGCs from stage X blastoderms were analyzed. Two reporter genes, SV-$\beta$gal and RSV-GFP, were introduced into the PGCs. Expression of bacterial/gal was improved by complexing DNA with liposome detectedcc in 75% of embryos at 3 days embryos. At the embryos incubated for 1 day, expression of the GFP was observed all the embryos. At day 3 of incubation, GFP was detected in about 70% of the manipulated embryos. In case of GFP, expression of the transgene was detected in 30 %e of the manipulated embryos. These results suggested that the cells is one of the most promising vectors for transgenesis. The established strategy should be very powerfull for application to poultry biotechnology.

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Camparison between the 1 Day and the 2 Day Protocols of Lymphoscintigraphy and Sentinel Node Biopsy using Subareolar Injection in Breast Cancer Patients: A Retrospective Study (유륜하 주사에 의한 유방암 환자의 전초림프절 스캔과 전초림프절 생검에 있어서 당일검사와 전날검사의 비교: 후향적 연구)

  • Seok, Ju-Won;Jun, Sung-Min;Nam, Hyun-Yeol;Kim, In-Ju
    • Nuclear Medicine and Molecular Imaging
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    • v.43 no.1
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    • pp.55-59
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    • 2009
  • Purpose: Lymphoscintigraphy and sentinel node biopsy are used in detection of axillary lymph node metastasis in breast cancer patients, but standardized technique is not established. We compared the results of the injection the morning of surgery (1 day protocol) with the subareolar injection the day before surgery (2 day protocol) with the subareolar injection in patients with breast cancer having lymphoscintigraphy and sentinel node biopsy. Materials and Methods: This study included 349 patients who underwent the breast cancer operation during 2001-2004. One hundred seventy one patients (1 day protocol, 1 hour) was injected 0.8ml of Tc-99m Tin-Colloid (37 MBq) by subareolar injection on the morning of surgery. One hundred seventy eight patients (2 day protocol, 16 hour) was injected 0.8 ml of T c-99m Tin-Colloid (185 MBq) on the afternoon before surgery. Lymphoscintigraphy was performed in sitting position and sentinel node localization was performed by hand-held gamma probe during operation. Result: In the 1 day protocol, 153 cases (89.5%) of the sentinel node were localized by lymphoscintigraphy and 150 cases (87.7%) were localized by gamma probe. In the 2 day protocol, 159 cases (89.3%) were localized by lymphoscintigraphy and 154 cases (86.5%) were localized by gamma probe. There was no significant difference in localization of sentinel node between the 1 day and the 2 day protocol by lymphoscintigraphy and gamma probe (p>0.05, p>0.05). Conclusion: There was no difference the result of localization of sentinel node with subareolar injection between the 1 day and the 2 day protocol in breast cancer patients. Because the 2 day protocol allows the enough time of performing lymphoscintigraphy, it is more useful in localization of sentinel node in breast cancer patients.

Epidemiological Studies on Giardia Infection Associated with environmental Pollution (Giardia에 의한 환경오염(環境汚染)과 감염(感染)에 관한 역학적(疫學的) 연구(硏究))

  • Lee, Keun-Tae;Kim, Seok-Chan;Song, Jong-Sool;Chung, Pyung-Rim
    • Journal of agricultural medicine and community health
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    • v.9 no.1
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    • pp.56-66
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    • 1984
  • Giardia lamblia is a pathogenic flagellate causing intestinal disorders such as diarrhea, abdominal pain and malabsorption of nutrients. Giardia is mainly infected by the ingestion of contaminated foods per os. Craun (1979) has recently reported that mass infection of this flagellate through the contaminated water supply systems is one of public health hazards. Also, so-called traveller's diarrhea is sometimes caused by Giardia infection (CDC, U.S.A., 1971). However, a few epidemiological studies figuring out the mode of infection or control measures of Giardia infection has been done so far in Korea. The present study was aimed to know the prevalence of Giardia infection in several Korean populations, detectability of this flagellate in water systems and the viability of the cysts against sewages and disinfectants applying to drinking water. In the present study, 388 stool specimens from orphanage children in Chun-joo, Chung-joo, On-yang and Chun-an areas and 538 stool specimens from inhabitants in Woo-do, In-chon, and Chun-joo were examined by formalin-ether concentration technique to detect out Giardia cysts. On the other hand, water samples from 14 sites of Han River and its tributaries were collected in May through July, 1984. Fifty liter of water sample in each sampling site was then filtered through water filtering system deviced by U.S. Environmental Proutection Agency and the sediments rinsed out from the thread rolls, a part of water filtering system, were examined to detect out the Giardia cysts. In order to observe the viability of Giardia cysts in the sewage samples, the cysts were treated in it at $4^{\circ}C$ or $25^{\circ}C$ for 7 through 28 days. For this purpose, the cysts were also exposed to various concentrations of disinfectants such as chlorine, iodine and ozone gas for proper time intervals. After treatment, the viability test of the Giardia cysts were carried out by method of Rice and Schaefer (1981) with minor modification. The results obtained in this study were as follows : 1) The detection rates of G lamblia cysts in the stool specimens were 18.3% in orphans and 4.3% in general examinees. 2) The prevalences of Giardia Infection were higher in the young age groups than in-adults. The highest positive rate was 18.4% in the age group less than 10. 3) Of 14 water specimens sampled from Han River system and its tributaries around the Seoul area, the Giardia cysts were detected from 4 samples, and no cyst was found in the water supply systems. 4) The cysts treated in the sewage survived for 28 days at $4^{\circ}C$ and for 13 days at $25^{\circ}C$. 5) The cysts were completely destroyed within 60 minutes by exposure to 8 mg/l of residual chlorine at 4g and within 30 minutes by exposure to the same concentration of chlorine at $25^{\circ}C$. 6) The cysts were all dead when exposed to 1 mg/1 of iodine for 60 minutes at $4^{\circ}C$ or $25^{\circ}C$. 7) The cysts were destroyed after 10 minute exposure in 0.15 mg to 0.25mg of residual ozone gas per liter. Summarizing the above results, it is considered that Giardia infection is regarded as water-borne disease and the cysts are able to be controlled by the application with the disinfectants in the water supply systems.

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