Comparison of the characteristics of Mycobacterium tuberculosis isolates from sputum and lung lesions in chronic tuberculosis patients.

Mycobacterium tuberculosis (Mtb) in sputum originates from lung cavities in tuberculosis (TB) patients. But drug susceptibility testing (DST) of sputum Mtb can not be conducted the same as in the lung because mutagenesis of bacilli may be happening in the lung during treatment and result in the possibility of the presence of heterogeneous drug-resistant subpopulations in the different lung lesions. This could be one of the reasons for low cure rates for multi-drug resistant (MDR)-TB. We studied the resected lungs of nine surgery patients with chronic TB. The isolates isolated from the sputum and different lung lesions of each patient were tested for phenotypic DST and genotyped using restriction fragment length polymorphism (RFLP) typing method. Genetic analysis to resistance to first and second line drugs was also performed. Five of nine patients were MDR-TB and three XDR-TB. DST results for ten anti-TB drugs were in accordance among different lung lesions in eight patients. However, only three of these eight patients showed the concordance of DST with sputum. Even though the isolates were heteroresistant, genotyping them by RFLP showed the clonal population in each individual patient. Six of eight followed-up patients achieved successful cure. In conclusion, the heteroresistance between sputum and lung lesions and a clonal population without mixed infection might provide useful information in establishing treatment regimen and surgery decision for MDR- and XDR-TB.

High-quality cell block preparation from scraping of conventional cytology slide: a technical report on a modified cytoscrape cell block technique.

BACKGROUND: Immunocytochemistry (ICC) on formalin-fixed paraffin embedded cell blocks is an ancillary tool commonly recruited for differential diagnoses of fine needle aspiration cytology (FNAC) samples. However, the quality of conventional cell blocks in terms of adequate cellularity and evenness of distribution of cytologic material is not always satisfactory for ICC. We introduce a modified agarose-based cytoscrape cell block (CCB) technique that can be effectively used for the preparation of cell blocks from scrapings of conventional FNAC slides. METHODS: A decoverslipped FNAC slide was mounted with a small amount of water. The cytological material was scraped off the slide into a tissue mold by scraping with a cell scraper. The cytoscrape material was pelleted by centrifugation and pre-embedded in ultra-low gelling temperature agarose and then re-embedded in conventional agarose. The final agarose gel disk was processed and embedded in paraffin. RESULTS: The quality of the ICC on the CCB sections was identical to that of the immunohistochemical stains on histological sections. By scrapping and harvesting the entirety of the cytological material off the cytology slide into a compact agarose cell button, we could avoid the risk of losing diagnostic material during the CCB preparation. CONCLUSION: This modified CCB technique enables concentration and focusing of minute material while maintaining the entire amount of the cytoscrape material on the viewing spot of the CCB sections. We believe this technique can be effectively used to improve the level of confidence in diagnosis of FNAC especially when the FNAC slides are the only sample available.

Relationships between Single Nucleotide Polymorphism Markers and Meat Quality Traits of Duroc Breeding Stocks in Korea.

This study was conducted to determine the relationships of five intragenic single nucleotide polymorphism (SNP) markers (protein kinase adenosine monophosphate-activated γ3 subunit [PRKAG3], fatty acid synthase [FASN], calpastatin [CAST], high mobility group AT-hook 1 [HMGA1], and melanocortin-4 receptor [MC4R]) and meat quality traits of Duroc breeding stocks in Korea. A total of 200 purebred Duroc gilts from 8 sires and 40 dams at 4 pig breeding farms from 2010 to 2011 reaching market weight (110 kg) were slaughtered and their carcasses were chilled overnight. Longissimus dorsi muscles were removed from the carcass after 24 h of slaughter and used to determine pork properties including carcass weight, backfat thickness, moisture, intramuscular fat, pH24h, shear force, redness, texture, and fatty acid composition. The PRKAG3, FASN, CAST, and MC4R gene SNPs were significantly associated with the meat quality traits (p<0.003). The meats of PRKAG3 (A 0.024/G 0.976) AA genotype had higher pH, redness and texture than those from PRKAG3 GG genotype. Meats of FASN (C 0.301/A 0.699) AA genotype had higher backfat thickness, texture, stearic acid, oleic acid and polyunsaturated fatty acid than FASN CC genotype. While the carcasses of CAST (A 0.373/G 0.627) AA genotype had thicker backfat, and lower shear force, palmitoleic acid and oleic acid content, they had higher stearic acid content than those from the CAST GG genotype. The MC4R (G 0.208/A 0.792) AA genotype were involved in increasing backfat thickness, carcass weight, moisture and saturated fatty acid content, and decreasing unsaturated fatty acid content in Duroc meat. These results indicated that the five SNP markers tested can be a help to select Duroc breed to improve carcass and meat quality properties in crossbred pigs.

Carcass Characteristics and Meat Quality of Korean Native Ducks and Commercial Meat-type Ducks Raised under Same Feeding and Rearing Conditions.

This study was conducted to compare carcass characteristics and physico-chemical meat quality in two different genotype ducks raised under identical feeding and rearing conditions. A total of ninety 1-d-old Korean native ducks (KND, n = 45) and commercial meat-type ducks (Grimaud, n = 45) were fed same experimental diets during 56 d and 42 d, respectively to obtain similar slaughter weights. The experimental diet for starter period contained 20% crude protein (CP) and 2,900 kcal nitrogen corrected true metabolizable energy (TMEn)/kg of diet and that for grower period contained 17% CP and 3,050 TMEn/kg of diet. Average daily gain and feed efficiency of KND were inferior to those of commercial meat-type ducks (p<0.05). Carcass weight was not different between two genetically different ducks, but carcass yield of KND was significantly higher (p<0.05) than that of commercial meat-type ducks. There were no significant differences in cooking loss and pH of breast meat between two genetically different ducks, but water holding capacity of KND was significantly higher than that of commercial meat-type ducks. The linoleic acid and total polyunsaturated fatty acid of breast meat from KND were significantly higher (p<0.05) than the corresponding part from commercial meat-type ducks. Significant differences were detected in water holding capacity and the content of linoleic acid and polyunsaturated fatty acid, which were significantly higher in KND, whereas growth performance tended to be superior in commercial ducks. At the market weight, the meat from KND was judged to have better qualities with regard to higher water holding capacity and greater content of polyunsaturated fatty acid compare with meat from commercial meat-type duck.

Evaluation of dietary multiple enzyme preparation (natuzyme) in laying hens.

The current experiment was designed to evaluate the efficacy of adding the multi-enzyme mixture (Natuzyme) into layers' diets with different levels of energy and available phosphorus in relation to laying performance, egg qualities, blood cholesterol level, microflora and intestinal viscosity. Two hundred and fifty 43-wk-old Hy-Line commercial layers were divided into five groups with five replicates per group (10 birds per replicate) and fed one of five experimental diets. A corn and soybean meal-based control diet was formulated and used as a control diet. Two experimental control diets were formulated to reduce energy and crude protein contents (rE) or energy, crude protein and phosphorus contents (rEP). In addition, Natuzyme was added into either rE (rE-Natu500) or rEP (rEP-Natu500) diet to reach a concentration of 500 mg per kg of diet. The experiment lasted 8 weeks. There were no significant differences in feed intake, egg production, egg weight, egg qualities such as eggshell color or Haugh unit, total cholesterol, relative organ weights and cecal microflora profiles between any dietary treatments. Natu500 supplementation into the rE diet, but not rEP diet significantly increased egg mass and eggshell qualities such as strength and thickness, but it decreased cecal ammonia concentration and intestinal viscosity in laying hens. In conclusion, the present study shows that adding multiple enzyme preparation could improve performance of laying hens fed energy and protein restricted diets.

Clinical outcomes of Pneumocystis carinii pneumonia in adult liver transplant recipients.

PURPOSE: Pneumocystis carinii pneumonia (PCP) is an opportunistic infection associated with morbidity and mortality in solid-organ transplant recipients. We retrospectively assessed the characteristics and outcomes of liver transplant (OLT) recipients with PCP compared with those of patients with severe non-P carinii pneumonia (non-PCP) who required intensive care with mechanical ventilation. METHODS: During the 2-year period between January 2008 and December 2009, 43 adult OLT recipients had severe pneumonia requiring mechanical ventilation; of these, 8 (19%) had PCP. During this period, routine antibiotic prophylaxis was administered for the first 6 months after OLT. RESULTS: The median period from OLT to development of PCP was 9.5 months (range, 1-67); the 1-year incidence was 0.9%. The 6 and 6 to 12-month incidences of non-PCP were 4.2% and 0.3%, respectively, and those of PCP were 0.3% and 0.6%, respectively. Four of 8 patients (50%) in the PCP group had a recent history of a rejection episode. PCP was associated with a higher incidence of prior antirejection treatment. There were no significant differences between PCP and non-PCP groups in age, gender, preoperative Model for End-stage Liver Disease score, primary diagnosis, graft type, and total number of rejection episodes. CONCLUSIONS: These results indicate that the risk of PCP in OLT recipients is closely related to strong immunosuppressive treatment for acute cellular rejection episodes, suggesting the importance of PCP prophylaxis in these patients. Because most patients developed PCP at around 1 year, it may be advisable to prolong routine post-OLT PCP prophylaxis for 12 months, especially among patients receiving antirejection treatment.

Nutritional and Hormonal Induction of Fatty Liver Syndrome and Effects of Dietary Lipotropic Factors in Egg-type Male Chicks.

This experiment was conducted with male chicks to investigate the influence of hormones and nutrients on the development of fatty liver syndrome (FLS) as well as the effects of dietary lipotropic factors on hepatic fat accumulation and lipogenic enzyme gene expression. A total of two-hundred sixteen 4-wk-old Hy-Line male chicks were divided into six groups and fed an experimental diet (T1, low-energy diet with low levels of lipotropic factors; T2, high-energy diet with low levels of lipotropic factors; T3 and T5, low-energy diet with high levels of lipotropic factors; T4 and T6, high-energy diet with high levels of lipotropic factors) for six weeks. The chicks in T5 and T6 groups were treated with intramuscular injections of estradiol benzoate for three days prior to biopsy and clinical analysis of FLS. Chicks treated with estrogen had significantly greater liver weights than untreated chicks. The abdominal fat contents were increased in chicks consuming high-energy diets as compared to those consuming low-energy diets. Treatment with estrogen significantly increased the concentrations of serum cholesterol, triacylglycerol and phospholipid (p<0.05). The hepatic triacylglycerol levels were tenfold higher in the estrogen treated chicks than in the untreated chicks. There were no significant differences in malondialdehyde levels between the treatment groups. Estrogen treatment dramatically increased the levels of fatty acid synthetase, acetyl-CoA carboxylase and ApoB mRNA. The results indicated that treatment with exogenous estrogen in growing male chicks induced hepatic fat accumulation, which might be partially due to increased lipogenic enzyme gene expression.

Safety of ultra-rapid intravenous infusion of hepatitis B immunoglobulin in liver transplant recipients.

PURPOSE: To evaluate the safety of institutional protocol for ultra-rapid hepatitis B immunoglobulin (HBIG) infusion (10,000 IU in 30 minutes) for hepatitis B virus prophylaxis in adult liver transplant recipients. METHODS: In this case-controlled study, prospectively recruited liver transplant recipients received ultra-rapid infusions of HBIG (10,000 units in 30 minutes) for 6 months. The historical control group consisted of patients who had received 1-hour HBIG infusions (conventional rapid infusion) for the precedent 6 months. RESULTS: We found that 1472 patients had received 5744 ultra-rapid HBIG infusions, whereas 1343 patients had received 5200 conventional rapid HBIG infusions. Adverse side-effects were observed after 7 (0.13%) and 9 (0.16%) infusions, respectively (P = .763). The number of infusions per month increased significantly, from 878 ± 34 before the introduction of ultra-rapid infusion to 957 ± 29 afterwards (P < .001), an increase of 10.5%. The maximal capacity of HBIG infusions per day in the outpatient clinic increased from 53 for conventional rapid infusion to 65 for ultra-rapid infusion, without expansion of the outpatient facility or equipment. CONCLUSIONS: Nearly all adult liver recipients able to tolerate 1-hour infusions of HBIG can also tolerate ultra-rapid infusions well. Thus, it seems to be reasonable to perform ultra-rapid infusion protocol widely for patient convenience.

Intractable recurrent hepatitis A virus infection requiring repeated liver transplantation: a case report.

Although hepatitis A virus (HAV) infection is usually self-limited, it may induce fulminant hepatitis. We present an unusual case of a 40-year-old, otherwise healthy man with intractable recurrent HAV infection requiring retransplantation after primary liver transplantation for HAV-associated fulminant liver failure. After the first living-donor liver transplantation, allograft function recovered uneventfully; however, beginning at 35 days, his serum total bilirubin concentration increased, reaching 40 mg/dL, with a slight increase in liver enzymes. Detection of genomic HAV RNA in serum at the time of graft dysfunction led to a diagnosis of recurrent HAV infection. Fifty-one days after the first transplant, he underwent a deceased donor retransplantation. His allograft function recovered; the patient was discharged from the hospital. Sixty-five days later, however, he was readmitted for colitis-like symptoms and was again treated for acute rejection, but died owing to overwhelming sepsis and persistence of HAV infection. These findings indicate that patients who undergo liver transplantation for HAV-associated liver disease may be at risk of HAV reinfection, particularly if they require anti-rejection therapy. Routine measurements of anti-HAV immunoglobulin M and HAV RNA during the early posttransplant period in HAV-associated liver transplant recipients may differentiate reinfection from an acute cellular rejection episode.

Peritransplant monitoring of immune cell function in adult living donor liver transplantation.

PURPOSE: We evaluated the clinical utility of peritransplant in vitro assays of immune cell function in adult living donor liver transplant (LDLT) recipients. METHODS: In particular, we measured immune cell function, using the ImmuKnow assay, in 107 adult LDLT recipients and 200 potential living liver donors (control group) admitted to our center between July 2008 and January 2009. RESULTS: In the control group, the mean proportion of T-helper/inducer cells was 36.8% ± 8.2%. The degree of immune response was strong in 12%, moderate in 77%, and low in 11%. In the study group, the degree of immune response within the first month was strong in 4.6%, moderate in 38.2%, and low in 57.2%, thus significantly lower than in the control group (P < .001). ImmuKnow results and tacrolimus levels did not show a significant correlation (r(2) = .002, P = .392). Although six patients showed biopsy-proven acute cellular rejection, none showed a strong immune response. Patients with overt infection showed a lower immune response. CONCLUSIONS: These results indicate that peritransplant assessment of immune response using the ImmuKnow assay does not reliably predict the occurrence of acute rejection. Additional studies are necessary to accurately assess the clinical utility of immune response monitoring.

An increase in deceased donor incidence alleviated the need for urgent adult living donor liver transplantation in a Korean high-volume center.

PURPOSE: This study analyzed the effects of a recent increase in deceased donors on the pattern of adult liver transplantation (OLT) in a high-volume center in Korea. METHODS: OLT patterns relative to pretransplant recipient status were analyzed for 112 deceased donor LTs (DDLT) and 743 living donor OLT (LDLT) in a single center as compared to nationwide Korean data over 3 years from 2006 to 2008. RESULTS: During the study period, the annual proportion of institutional urgent OLT was relatively invariable (20% to 25.2%), but the annual proportion of DDLTs to all OLT increased from 8.9% to 19.9%, as did the annual rate of DDLTs among those undergoing urgent OLT, from 18.6% to 65.8%, with a reciprocal decrease in the proportion of urgent LDLTs. Korean nationwide data also showed a noticeable increase in deceased liver graft allocation for urgency from 39.8% to 62.2% over the same time period. CONCLUSION: An increase in deceased donors up to 5 per million enabled an increase in urgent adult DDLTs, alleviating the need for urgent adult LDLTs in Korea.

Bioelectrical impedance analysis for evaluation of donor hepatic steatosis in living-donor liver transplantation.

OBJECTIVE: To assess whether bioelectrical impedance analysis (BIA) can be used to evaluate the degree of hepatic steatosis in potential living liver donors. MATERIAL AND METHODS: From May 2008 to April 2009, BIA was measured in 302 living donor candidates. Correlations among body mass index (BMI; calculated as weight in kilograms divided by height in meters squared), total fatty changes at percutaneous needle liver biopsy, and BIA-derived fat composition were assessed. RESULTS: The median (range) BIA-derived fat proportion was 19.4% (4.8%-35.3%), BMI was 24 (17-39), and hepatic steatosis at liver biopsy was 2% (0%-75%). Crude correlations were observed between BIA-derived fat proportion and hepatic steatosis (r(2) = 0.14; P = .000), between BMI and hepatic steatosis (r(2) = 0.27; P = .000), and between BMI and BIA-derived fat proportion (r(2) = .25; P = .000). Receiver operating characteristic curve analysis revealed that the area under the curve of BIA-derived fat proportion was smaller than that of BMI, and no significant cutoff value was identified. CONCLUSIONS: These results suggest that BIA-derived fat composition alone cannot be used to accurately determine the degree of hepatic steatosis. However, a combination of BMI and BIA-derived fat composition may increase clinical ability to assess hepatic steatosis.

Notch1 confers thymocytes a resistance to GC-induced apoptosis through Deltex1 by blocking the recruitment of p300 to the SRG3 promoter.

One notable phenotypic change during the differentiation of immature thymocytes into either mature CD4 or CD8 single-positive lineages is the acquisition of a resistance to glucocorticoid (GC)-induced apoptosis. We have previously reported that SRG3 is critical in determining the sensitivity for the GC-induced apoptosis in developing thymocytes. We report here that Notch signaling downregulates the transcriptional activation of SRG3 through N-box and/or E-box elements on its promoter. RBP-J represses SRG3 transcription through the N-box motif. On the other hand, Deltex1 competitively inhibits the binding of p300 to E2A/HEB protein bound to the E-box elements and represses the SRG3 promoter activity. Moreover, enforced expression of Deltex1 restored double-positive (DP) thymocyte survival from the GC-induced apoptosis. Our results suggest that Notch signaling confers differentiating DP thymocytes resistance to GCs by regulating the SRG3 expression through Deltex1, and that Deltex1 and SRG3 may play a significant role during DP thymocyte maturation.

A research note on predicting the carcass yield of Korean native cattle (Hanwoo).

This study developed a new equation to predict the carcass yield of Hanwoo cattle, as well as re-evaluating a previous prediction equation. Experimental animals comprised 79 cows, 79 steers, and 79 bulls. A stepwise model selection was performed to determine the most practical carcass traits for predicting the yield. Cold carcass weight (CW), backfat thickness (BFT), and ribeye area (REA) accounted for 52% variation in yield, and these were determined as the final parameters. When the kidney, pelvic, and heart fat were included in the model, this increased the percentage variation explained (R(2)) by 4%. To compare the newly developed equation (Yield=64.65-0.0198×CW-5.2264×BFT+0.1339×REA) and the previously used one, carcass yields of 377,048 industrial animals (145,695 cows, 225,926 bulls, and 5427 steers) were assessed. For the newly developed equation, the mean difference between experimental animals industrial animals differed only by 1.99-2.68% for all sex groups. In the case of the previous prediction equation, the mean difference ranged from 6.06% for bulls to 11.05% for steers. The results demonstrated that the prediction equation should use a mixture of sex and market weight groups. The results also support our decision to use the newly developed model in predicting the yield of Hanwoo.

Notch1 confers a resistance to glucocorticoid-induced apoptosis on developing thymocytes by down-regulating SRG3 expression.

We previously have reported that SRG3 is required for glucocorticoid (GC)-induced apoptosis in the S49.1 thymoma cell line. Activation of Notch1 was shown to induce GC resistance in thymocytes. However, the specific downstream target of Notch1 that confers GC resistance on thymocytes is currently unknown. We found that the expression level of SRG3 was critical in determining GC sensitivity in developing thymocytes. The expression of SRG3 also was down-regulated by the activated form of Notch1 (NotchIC). The promoter activity of the SRG3 gene also was down-regulated by NotchIC. Expression of transgenic SRG3 resulted in the restoration of GC sensitivity in thymocytes expressing transgenic Notch1. These results suggest that SRG3 is the downstream target of Notch1 in regulating GC sensitivity of thymocytes.

Peripheral T cells become sensitive to glucocorticoid- and stress-induced apoptosis in transgenic mice overexpressing SRG3.

Immature double-positive thymocytes are sensitive to glucocorticoid (GC)-induced apoptosis, whereas mature single-positive T cells are relatively resistant. Thymocytes seem to acquire resistance to GCs during differentiation into mature single-positive thymocytes. However, detailed knowledge concerning what determines the sensitivity of thymocytes to GCs and how GC sensitivity is regulated in thymocytes during development is lacking. We have previously reported that the murine SRG3 gene (for SWI3-related gene) is required for GC-induced apoptosis in a thymoma cell line. Herein, we provide results suggesting that the expression level of SRG3 protein determines the GC sensitivity of T cells in mice. SRG3 associates with the GC receptor in the thymus, but rarely in the periphery. Transgenic overexpression of the SRG3 protein in peripheral T cells induces the formation of the complex and renders the cells sensitive to GC-induced apoptosis. Our results also show that blocking the formation of the SRG3-GC receptor complex with a dominant negative mutant form of SRG3 decreases GC sensitivity in thymoma cells. In addition, mice overexpressing the SRG3 protein appear to be much more susceptible to stress-induced deletion of peripheral T cells than normal mice, which may result in an immunosuppressive state in an animal.

Mechanism of growth inhibitory effect of Mitomycin-C on cultured human retinal pigment epithelial cells: apoptosis and cell cycle arrest.

PURPOSE: To investigate the therapeutic potential of Mitomycin-C (MMC) in the management of proliferative vitreoretinopathy, the antiproliferative effect of MMC on cultured human retinal pigment epithelial (RPE) cells were investigated in vitro. METHODS: Drug sensitivities of cultured human RPE cells to MMC were determined using the tetrazolium dye assay. In order to detect the presence of apoptosis, DNA fragmentation was assessed by DAPI staining, and TdT-dUTP nick-end labeling (TUNEL) assay. The relative amount of DNA fragmentation was quantified by flow cytometric analysis. To analyze the cell cycle response of RPE cells to MMC, flow cytometric analysis of propidium iodide stained nuclei was performed. The levels of proteins related to DNA damage in the RPE cells were then determined by Western blot analysis. RESULTS: MMC inhibited cell proliferation in a dose-dependent manner. The majority of RPE cells following treatment with 10 microg/ml of MMC exhibited fragmented nuclei as observed by DAPI staining and TUNEL assay. Cell cycle analysis demonstrated an accumulation of cells arrested in S and G2/M phase following treatment with 1 microg/ml of MMC. At 10 microg/ml of MMC, a dramatic increase of the cell population in the sub G1 peak, which can be considered a marker of cell death by apoptosis, was observed by flow cytometry. Western blot analysis of p53 and p21 revealed a gradual increase in the level of these proteins when RPE cells were exposed to increasing concentrations of MMC. CONCLUSIONS: This study demonstrated that the response of RPE cells to MMC was bi-directional: 1) partial arrest of the cell cycle at S, G2/M phase, and 2) induction of apoptotic cell death.

Corneal flap dimensions in laser in situ keratomileusis using the Innovatome automatic microkeratome.

To evaluate the thickness and size consistency of the corneal flap created with the Innovatome automatic microkeratome and to determine any correlation between preoperative variables and these corneal flap dimensions, we performed a prospective study comprising of 268 eyes of 143 patients having laser in situ keratomileusis. Either No. 170 or No. 190 blade was used, and preoperative variables including the central corneal thickness, keratometry (K) reading, spherical equivalent, and the blade type were measured. The mean central corneal flap thickness was 138.8 +/- 23.5 microns (range, 71.6-193.7 microns) in blade 170 group, and 148.3 +/- 25.4 microns (range, 80.3-211.7 microns) in blade 190 group. No relationship was found between the corneal flap thickness and the preoperative K reading or the spherical equivalent, but the corneal flap thickness increased with the preoperative central corneal thickness. The mean vertical flap diameter was 9.18 +/- 0.25 mm (range, 8.50-9.75 mm) in blade 170 group, and 9.50 +/- 0.31 mm (range, 8.75-10.00 mm) in blade 190 group. No relationship was found between the corneal flap diameter and the preoperative central corneal thickness or the spherical equivalent, but the corneal flap size increased with the preoperative K reading.

Excimer laser photorefractive keratectomy for astigmatism.

The effectiveness of excimer laser photorefractive keratectomy (PRK) for astigmatism was evaluated. We treated 136 eyes of naturally occurring myopic astigmatism using the 193-nm excimer laser with an expanding slit and an iris diaphragm, and followed for a minimum of 6 months. At 6 months after operation, the mean refractive cylinder decreased from 1.62 +/- 0.88 D preoperatively to 0.48 +/- 0.48 D. For detailed analysis of the results, the surgically induced refractive change (SIRC) was determined from the preoperative and postoperative refractions by vector analysis of astigmatism. When we compared the cylinder of the SIRC with the preoperative refractive cylinder, the effect of the cylindrical ablation was 93.9 +/- 36.7% at 6 months. The axial error of the cylinder of the SIRC to the preoperative cylindrical axis was 5.9 +/- 10.2 degrees at 6 months. These results suggest that excimer laser PRK with an expanding slit appears to have a significant effect for the correction of astigmatism.