Epithelial-mesenchymal transition profiles in triple negative breast carcinoma may explain its aggressive nature.

Epithelial-mesenchymal transition (EMT) is increasingly explored in cancer progression. Considering that triple negative (TN) breast cancer has the poorest survival among molecular subtypes, we investigated 49 TN, 45 luminal and 25 HER2-enriched female breast carcinomas for EMT expression (using E-cadherin and vimentin immunohistochemistry) against lymphovascular and/or lymph node invasion. E-cadherin and vimentin expressions were semi-quantitated for positive- cancer cells (0=0-<1%, 1=1-10%, 2 =11-50%, 3=>50%) and staining intensity (0=negative, 1=weak, 2=moderate, 3=strong), with final score (low=0-4 and high=6-9) derived by multiplying percentage and intensity scores for each marker. Low E-cadherin and/or high vimentin scores defined EMT positivity. Low E-cadherin co-existing with high vimentin defined "complete" (EMT-CV), while low E-cadherin (EMT-C) or high vimentin (EMT-V) occurring independently defined "partial" subsets. 38 (31.9%) cancers expressed EMT, while 59.2 % TN, 13.3% luminal and 12% HER2-enriched cancers expressed EMT (p<0.05). Among the cancers with lymphovascular and/or lymph node invasion, EMT positivity by molecular types were 66.7% TN, 7.4% luminal and 11.8% HER2-enriched (p<0.05). Although EMT-V, associated with stem-cell properties was the dominant TN EMT profile, EMT-CV, a profile linked to vascular metastases, was encountered only in TN. EMT appears important in TN cancer and different EMT profiles may be associated with its aggressive nature.

[Retrospective analysis of curative effect of total pelvic organ resection and anal preservation in 20 patients with recurrence of cervical cancer after radical radiotherapy].

Objective: To explore the surgical method and effect of en bloc pelvic resection and anal preservation after radical radiotherapy for cervical cancer. Methods: Clinical data of 20 cervical cancer patients with central recurrence after radical radiotherapy underwent en bloc pelvic resection in the Tumor Hospital of Zhengzhou University and Hainan Provincial People's Hospital from January 2013 to December 2017 were retrospectively analyzed. The operative time, intraoperative blood loss, length of stay, postoperative anal function and postoperative complications were evaluated. Results: The median operation time of 20 patients with anal preservation after en bloc pelvic resection was 135.2 min, the median intraoperative blood loss was 680 ml, and the median hospitalization time was 16.5 days. Among them, 18 patients had good postoperative healing, and the anal function gradually returned to normal within 6 months after surgery, defecated 1~2 times per day.One patient showed incomplete adhesion between the external colon and the anus. One patient presented with pre-sacral infection. Postoperative pathology confirmed the recurrences in 20 patients, of which 11 cases were squamous cell carcinoma, 7 cases were adenocarcinoma, 2 cases were adenosquamous cell carcinoma. Conclusions: It is safe and reliable to preserve anus after en bloc pelvic resection for cervical cancer patients with radical radiotherapy. The anus function is good enough to improve the postoperative life quality of patients significantly.

A critical review on life cycle assessment and plant-wide models towards emission control strategies for greenhouse gas from wastewater treatment plants.

For decades, there has been a strong interest in mitigating greenhouse gas (GHG) emissions from wastewater treatment plants (WWTPs). Numerous models were developed to measure the emissions and propose the quantification. Existing studies looked at the relationship between GHG emissions and operational cost (OCI), which is one of the most important indicators for decision-makers. Other parameters that can influence the control strategies include the effluent quality (EQI) and total environmental impacts. Plant-wide models are reliable methods to examine the OCI, EQI and GHG emissions while Life cycle assessment (LCA) works to assess the potential environmental impacts. A combined LCA and plant-wide model proved to be a valuable tool evaluating and comparing strategies for the best performance of WWTPs. For this study involving a WWTP, the benchmark model is used while LCA is the decision tool to find the most suitable treatment strategy. LCA adds extra criteria that complement the existing criteria provided by such models. Complementing the cost/performance criteria is proposed for plant-wide models, including environmental evaluation, based on LCA, which provides an overall better assessment of WWTPs. It can capture both the dynamic effects and potential environmental impacts. This study provides an overview of the integration between plant-wide models and LCA.

Screening for microsatellite instability in colorectal carcinoma: Practical utility of immunohistochemistry and PCR with fragment analysis in a diagnostic histopathology setting.

Since 2014, the National Comprehensive Cancer Network (NCCN) has recommended that colorectal carcinoma (CRC) be universally tested for high microsatellite instability (MSI-H) which is present in 15% of such cancers. Fidelity of resultant microsatellites during DNA replication is contingent upon an intact mismatch repair (MMR) system and lack of fidelity can result in tumourigenesis. Prior to commencing routine screening for MSI-H, we assessed two commonly used methods, immunohistochemical (IHC) determination of loss of MMR gene products viz MLH1, MSH2, MSH6 and PMS2 against PCR amplification and subsequent fragment analysis of microsatellite markers, BAT25, BAT26, D2S123, D5S346 and D17S250 (Bethesda markers) in 73 unselected primary CRC. 15.1% (11/73) were categorized as MSI-H while deficient MMR (dMMR) was detected in 16.4% (12/73). Of the dMMR, 66.7% (8/12) were classified MSI-H, while 33.3% (4/12) were microsatellite stable/low microsatellite instability (MSS/MSI-L). Of the proficient MMR (pMMR), 95.1% (58/61) were MSS/MSI-L and 4.9% (3/61) were MSI-H. The κ value of 0.639 (standard error =0.125; p = 0.000) indicated substantial agreement between detection of loss of DNA mismatch repair using immunohistochemistry and the detection of downstream microsatellite instability using PCR. After consideration of advantages and shortcomings of both methods, it is our opinion that the choice of preferred technique for MSI analysis would depend on the type of laboratory carrying out the testing.

Can algae-based technologies be an affordable green process for biofuel production and wastewater remediation?

Algae is a well-known organism that its characteristic is prominent for biofuel production and wastewater remediation. This critical review aims to present the applicability of algae with in-depth discussion regarding three key aspects: (i) characterization of algae for its applications; (ii) the technical approaches and their strengths and drawbacks; and (iii) future perspectives of algae-based technologies. The process optimization and combinations with other chemical and biological processes have generated efficiency, in which bio-oil yield is up to 41.1%. Through life cycle assessment, algae bio-energy achieves high energy return than fossil fuel. Thus, the algae-based technologies can reasonably be considered as green approaches. Although selling price of algae bio-oil is still high (about $2 L-1) compared to fossil fuel's price of $1 L-1, it is expected that the algae bio-oil's price will become acceptable in the next coming decades and potentially dominate 75% of the market.

Tobacco smoke exposure and multiplexed immunoglobulin E sensitization in children: a population-based study.

BACKGROUND: Although there is evidence that exposure to tobacco smoke is harmful to children's respiratory health, the effects of tobacco smoke exposure on the regulation of immunoglobulin E (IgE)-mediated immune responses to specific allergens remain unclear. This study aimed to investigate the relationship between objectively assessed tobacco smoke exposure and specific IgE profiles for a broad spectrum of allergens in a population setting. METHODS: Children aged 5-18 years (N = 1315) were assessed using serum cotinine measurement and microarray-based multiplexed detection of specific IgE against 40 allergens. RESULTS: Serum cotinine levels were positively associated with sensitization to foods (adjusted odds ratio [AOR] = 4.95; 95% CI: 1.59-15.34), cockroaches (AOR = 3.77; 95% CI: 1.49-9.51), and pollen (AOR = 2.84; 95% CI: 1.20-6.73) while the association was borderline significant for animals (AOR = 2.53; 95% CI: 0.92-6.93). No associations were found for sensitization against mites, mold, and latex. When considering the degree of allergic sensitization, serum cotinine levels were positively correlated to the number of sensitization to cockroaches (P = 0.004), pollen (P = 0.006), and foods (P < 0.001), with statistically significant positive dose-response relationships (all P < 0.01). Similar results were observed when summing up specific IgE concentrations for the aforementioned allergen categories. CONCLUSIONS: The association between tobacco smoke exposure and IgE sensitization to environmental allergens varies for different allergens among children. This study demonstrates that elevated serum cotinine levels are significantly associated with IgE sensitization to cockroaches, grass pollen, and certain foods, with potential dose-dependent relationships.

Bcl-2 stabilization by paxillin confers 5-fluorouracil resistance in colorectal cancer.

5-Fluorouracil (5-FU) is chemotherapeutic agent widely used for the treatment of colorectal cancer. Unfortunately, advanced colorectal cancer is often resistance to such chemotherapy and poor outcome. An adaptor protein paxillin (PXN) is phosphorylated at Y31/Y118 (pPXN-Y31/Y118) by Src contributes to cell mobility and Ser (S)272 of PXN in LD4 domain is important to the interaction between PXN and Bcl-2. We thus hypothesized that pPXN-Y31/Y118 may be required for Bcl-2 protein stability via PXN interacting with Bcl-2 to confer 5-FU resistance in colorectal cancer. Mechanistically, pPXN-S272 is phosphorylated through pPXN-Y31/Y118-mediated p21 protein-activated kinase 1 (PAK1) activation and pPXN-S272 is required for PXN to interact with Bcl-2. The interaction between PXN and Bcl-2 is essential for Bcl-2 protein stability through phosphorylation of Bcl-2 at S87 (pBcl-2-S87) by pPXN-Y31/Y118-mediated ERK activation. An increase in Bcl-2 expression by PXN is responsible for resistance to 5-FU. The resistance to 5-FU can be abolished by inhibitor of Src and PAK1 or Bcl-2 antagonist in cell and animal models. Among patients, Bcl-2 expression is positively correlated with expression of PXN and pPXN-S272, respectively. Patients with high PXN/high Bcl-2 or high pPXN-S272/high Bcl-2 tumors are commonly to have an unfavorable response to 5-FU-based chemotherapy, compared with patients who have high PXN, high pPXN-S272 or high Bcl-2 tumors alone. Therefore, we suggest that Src, PAK1 or Bcl-2 inhibitor may potentially overcome the resistance of 5-FU-based chemotherapy and consequently to improve outcomes in patients with PXN/Bcl-2 and pPXN-S272/Bcl-2-positive tumors.

Deferoxamine promotes osteoblastic differentiation in human periodontal ligament cells via the nuclear factor erythroid 2-related factor-mediated antioxidant signaling pathway.

BACKGROUND AND OBJECTIVE: Recently it was reported that deferoxamine (DFO), an iron chelator, stimulates bone formation from MG63 and mesenchymal stem cells, but inhibits differentiation in rat calvarial cells; however, the effect of DFO on osteoblastic differentiation in human periodontal ligament cells (hPDLCs) has not been reported. The aim of this study was to investigate the effects and the possible underlying mechanism of DFO on osteoblastic differentiation of hPDLCs. MATERIAL AND METHODS: The effect of DFO on osteoblast differentiation was determined by the staining intensity of calcium deposits with Alizarin red and by RT-PCR analysis of the expression of osteoblastic markers. Signal transduction pathways were analyzed by western blotting. RESULTS: DFO increased osteogenic differentiation in a concentration-dependent manner by expression of the mRNA for differentiation markers and calcium nodule formation. Exposure of hPDLCs to DFO resulted in increases in the production of reactive oxygen species and in the levels of nuclear factor erythroid 2-related factor (Nrf2) protein in nuclear extractions, as well as a dose-dependent increase in the expression of Nrf2 target genes, including glutathione (GSH), glutathione S-transferase, γ-glutamylcysteine lygase, glutathione reductase and glutathione peroxidase. Pretreatment with Nrf2 small interfering RNA, GSH depletion by buthionine sulfoximine and diethyl maleate, and with antioxidants by N-acetylcysteine and vitamin E, blocked DFO-stimulated osteoblastic differentiation. Furthermore, pretreatment with GSH depletion and antioxidants blocked DFO-induced p38 MAPK, ERK, JNK and nuclear factor-kappaB pathways. CONCLUSION: These data indicate, for the first time, that nontoxic DFO promotes osteoblastic differentiation of hPDLCs via modulation of the Nrf2-mediated antioxidant pathway.

Autotransplantation of mesiodens for missing maxillary lateral incisor with cone-beam CT-fabricated model and orthodontics.

AIM: Autotransplantation is a viable treatment option for a missing tooth when there is a suitable donor, especially in adolescents with remaining facial growth. This report presents the aesthetic restoration of a missing maxillary lateral incisor through orthodontic treatment and autotransplantation of a mesiodens using a CBCT-fabricated rapid-prototyping model. SUMMARY: A 14-year-old male patient with a congenitally missing maxillary lateral incisor was referred from the Department of Orthodontics. The teeth were moved orthodontically to regain space for the missing lateral incisor and to close the space of the mesiodens after transplantation. A replica of the donor tooth was fabricated from a cone-beam computed tomography scan through a rapid-prototyping machine before autotransplantation surgery. The model was used to create a socket for the graft tooth, thereby shortening the extra-oral time and minimizing the damage to the root surface. After transplantation and orthodontic tooth movement, the mesiodens was finally restored with an aesthetic laminate restoration. Over 3 years, the aesthetics remained excellent, and the transplant functioned normally without any signs or symptoms of root resorption. KEY LEARNING POINT: Missing anterior teeth may be replaced through a combination of orthodontics, autotransplantation with a rapid-prototyping model and prosthodontic restoration, in growing patients.

The prognostic significance of APC gene mutation and miR-21 expression in advanced-stage colorectal cancer.

AIM: Colorectal cancer (CRC) is the second commonest cause of cancer death in Taiwan. Although numerous genes have been associated with tumorigenesis in colorectal cancer, only a few have been validated and used as biomarkers for predicting clinical outcome. The aim of this study was to analyse the association of APC gene mutation and miR-21 expression with clinical outcome in CRC patients. METHOD: In total, 195 colorectal cancer patients were enrolled in a single medical centre between 2003 and 2007. APC gene mutation and expression of APC and miR-21 were analysed by direct DNA sequencing and real-time reverse transcription polymerase chain reaction. The primary outcome included 5-year overall survival and univariate (Kaplan-Meier) and multivariate (Cox regression) analyses of prognostic factors. RESULTS: The results showed that 66 (33.8%) of 195 tumour tissues contained an APC mutation. The predominant APC gene variations were deletion mutations (50.0%). APC gene expression was low in CRC and negatively correlated with miR-21 expression and gene mutation. In advanced-stage cancer, patients with APC mutation/high miR-21 had poorer overall survival rates than those with APC mutation/low miR-21, APC wild-type/high miR-21 and APC wild-type/low miR-21. CONCLUSION: In Taiwan, downregulation of the APC gene in CRC correlated with gene mutation and miR-21 upregulation. APC mutation and miR-21 expression could be used to predict the clinical outcome of CRC, especially in patients with advanced disease.

Moxifloxacin modifies corneal fibroblast-to-myofibroblast differentiation.

BACKGROUND AND PURPOSE: Fibroblast-to-myofibroblast differentiation is associated with scarring, an important issue in corneal surgery. Moxifloxacin (MOX), commonly applied to prevent post-operative infection, would benefit more if it modifies fibroblast-to-myofibroblast differentiation other than antimicrobial activity. Our purpose was to explore whether MOX has anti-fibrotic effect in human corneal fibroblasts (HCFs). EXPERIMENTAL APPROACH: HCFs were incubated in MOX-containing medium concurrently with TGF-ß1 (co-treatment), before (pretreatment) or after (post-treatment) adding TGF-ß1. HCF contractility was evaluated with a type I collagen gel contraction assay. Expression of α-smooth muscle actin (α-SMA), Smad2, phospho-Smad2-Ser467, Smad4 and Smad7 was determined by immunoblotting. Formation of α-SMA-positive filaments and distribution of active Smad2 were observed under confocal microscopy. Expression of TGF-ß receptor types I (TGFBR1) and II (TGFBR2) was assessed with flow cytometry. KEY RESULTS: MOX did not affect gel contractility or α-SMA filament formation in HCFs without TGF-ß1 stimulation. MOX did, however, retard HCF-containing gel contractility and α-SMA filament formation following TGF-ß1 stimulation in the pretreatment and co-treatment groups but not in the post-treatment group. MOX blocked the expression of Smad2, phospho-Smad2-Ser467 and TGFBR1 under TGF-ß1 incubation. Additionally, MOX enhanced Smad7 expression in TGF-ß1-incubated HCFs, but did not interfere with TGF-ß-triggered Smad2 nuclear translocation or Smad4 expression. CONCLUSIONS AND IMPLICATIONS: MOX inhibited TGF-ß-induced fibroblast-to-myofibroblast differentiation via blocking TGFBR1 and enhancing Smad7 expression. MOX should be used before or during surgery to achieve these effects. These results suggest a de novo mechanism by which MOX participates in corneal wound healing.

Minimum-intensity projection for in-depth morphology study of mesiobuccal root.

OBJECTIVE: This micro-computed tomography (MCT) study investigated the utility of thin-slab minimum-intensity projection (TS-MinIP) technique as an adjunct to 3-dimensional (3D) modeling for in-depth morphology study. STUDY DESIGN: One hundred one extracted maxillary first molars were scanned for microtomographic analysis (SkyScan). Two-dimensional TS-MinIP and 3D images of mesiobuccal (MB) roots were produced and analyzed to record the number and configurations of the canals, the incidence and location of accessory canals, loop, and intercanal connections, and number of foramina. RESULTS: Multiple-canal MB roots were present in 76.2%, and all of the roots had intercanal communications. Weine type III configuration was the most common in the multiple-canal roots. Accessory canals were found in 78.2% of the roots. Configurations that were nonclassifiable were found in 10.9% of the MB roots. CONCLUSIONS: MB root canal anatomy was complex, and MinIP may serve as an adjunct to 3D modeling for in-depth morphology study.

The effect of obturator bulb height on speech in maxillectomy patients.

The purpose of this study was to compare the speech function of low height bulb obturators with that of high height bulb obturators. Thirteen maxillectomy patients, who underwent post-operative prosthodontic rehabilitations, were included. Two obturators of the same design except for different bulb heights were fabricated for each maxillectomy patient. One of the two obturators had high bulb design and the other had low bulb design. After one of the obturators was used for a period of 3 weeks, the patient's speaking functions were evaluated by measuring nasalance scores, formant frequencies, and vowel working space areas. The same procedures were repeated with the second obturator following another 3-week period of usage. In addition, the effect of delivery sequence and anatomic conditions related to maxillectomy were analysed. The results demonstrated that the nasalance scores with the low bulb obturators were significantly higher than those with the high bulb obturators. There were no significant differences in formant frequencies based on the bulb height of the obturators. The vowel working spaces for the two obturators were similar in shape and there were no significant differences between the vowel working space areas created by the two obturators. The delivery sequence affected the results. However, there were no significant differences related to the other anatomical variables. Although low bulb obturators might function similarly with high bulb obturators in terms of the articulation of speech, they would exhibit a difficulty in controlling hypernasality in maxillectomy patients.

Microbial degradation of benzene, toluene, ethylbenzene and xylene isomers (BTEX) contaminated groundwater in Korea.

A mixed culture derived from a gasoline-contaminated aquifer in Korea was enriched on toluene at 25 degrees C. A study was conducted to characterize the substrate interaction of BTEX by toluene-enriched consortia and determine the effects of initial BTEX concentration on BTEX degradation. Substrate degradation patterns in individual aromatics were found to differ significantly from patterns for aromatics in mixtures. In the experiment of a single substrate, toluene was degraded fastest, followed by benzene, ethylbenzene, and the xylenes. In BTEX mixtures, degradation followed the order of toluene, ethylbenzene, benzene, and the xylenes. The studies conducting with toluene-enriched consortia evaluated substrate interactions by the concurrent presence of multiple BTEX compounds and revealed a range of substrate interaction patterns including no interaction, stimulation, inhibition, and cometabolism. The simultaneous presence of benzene and toluene were degraded with a slight inhibitory effect on each other. Ethylbenzene was shown to be the most potent inhibitor of BTEX degradation. p-xylene also inhibited the degradation of benzene, toluene, and ethylbenzene, whereas the presence of either benzene or toluene enhanced the degradation of ethylbenzene and the xylenes.

The cornea in young myopic adults.

AIMS: To further understand the effect of refractive error on the corneal dimensions and function. METHODS: Corneal curvature, corneal thickness, and axial length measurements were performed, as well as specular microscopy and fluorophotometry, on patients with various refractive statuses. 216 subjects, mean age 22.2 (SD 4.2) years, were examined. Patients with previous contact lens wear history, external eye diseases, as well as previous ocular surgeries, were excluded. RESULTS: The corneas were flatter in eyes with longer axial length (r = -0.22, p = 0.003). Eyes with more myopic spherical equivalent had longer axial length (r = -0.90, p <0.001) as well as less corneal endothelial density (r = 0.20, p = 0.037). Corneal endothelial density decreased in eyes with longer axial length (r = 0.24, p = 0.019); however, it correlated neither with corneal thickness (r = -0.06, p = 0.59) nor with corneal curvature (r = -0.07, p = 0.52). The corneas had a mean corneal thickness of 533 (SD 29) microm and were thinner in more myopic eyes (r = 0.16, p = 0.021). The corneas tended to be thinner in eyes with longer axial length. However, the correlation did not reach statistical significance (r = -0.11, p = 0.14). Besides, there was no significant correlation between the corneal thickness and the corneal curvature (r = -0.13, p = 0.093) and the endothelial permeability (r = 0.042, p = 0.69). The corneas with higher endothelial density had larger corneal transfer coefficient (r = 0.26, p = 0.024) and higher permeability to fluorescein molecules (r = 0.28, p = 0.014). Nevertheless, the corneal endothelial permeability did not correlate significantly with either the axial length (r = -0.18, p = 0.11) or the degree of myopia (r = 0.12, p = 0.26). CONCLUSION: Changes in the anterior segments as the eyeball elongates in myopia progression included flatter corneal curvature, decreased corneal thickness, as well as decreased endothelial density. These factors should be considered in refractive surgery.

Klebsiella pneumoniae renal abscess.

BACKGROUND: The clinical characteristics of renal abscess caused by Klebsiella pneumoniae have not been previously reported in case-series studies. The purpose of this study is to demonstrate the clinical characteristics of K pneumoniae renal abscess for early diagnosis and to identify the clinical risk factors associating with poor prognosis. METHODS: We retrospectively reviewed the medical records of 24 patients with K pneumoniae renal abscess, from April, 1982 through February, 1998. The clinical presentations, including the demographic characteristics, predisposing disorders, initial signs and symptoms, laboratory test results, diagnostic radiology studies, therapeutic modalities and risk factors associated with mortality were studied. RESULTS: The mean age was 58.7 years and the male to female ratio was 10:14. The most common predisposing factors were diabetes mellitus (58%), urolithiasis (25%) and immunosuppression (17%). Fever, chills and flank pain were the most common symptoms and signs, whereas pyuria, elevation of leukocyte count, glucose, blood urea nitrogen and creatinine were the common laboratory features. The distinct complications of K pneumoniae renal abscess were bacteremia in 13 (54%), emphysematous pyelonephritis in five (21%), and metastatic septic infection in three (12.5%). The cure rate was 52% (11/21) in patients treated with a combination of antibiotics and percutaneous drainage; however, six (35%) patients who survived required another surgical procedure for complete recovery. The overall mortality rate was 25%. The clinical factors of elderly age (>65 years) at presentation, lethargy, elevation of serum blood urea nitrogen and pulmonary complications were associated with poor prognoses. CONCLUSIONS: Focusing on the early diagnosis of K pneumoniae renal abscess and recognition of the prognostic factors for a poor prognosis, we highlight the specific clinical characteristics that include elderly age, lethargy, impairment of renal function, metastatic septic lesions and pulmonary complications. All patients with K pneumoniae renal abscesses should receive empiric antibiotics and percutaneous drainage or aspiration, and surgical intervention as necessary for patients with intractable disease.

Wound healing patterns following perforation sustained during laser in situ keratomileusis.

BACKGROUND AND PURPOSE: Corneal perforation during laser in situ keratomileusis (LASIK) may interfere with flap adhesion and wound healing. The purpose of this study was to investigate wound healing patterns following corneal perforation sustained during LASIK in rabbits. METHODS: Forty-two pigmented rabbit eyes underwent LASIK surgery with 5.0-mm excimer laser treatment under the corneal flap. Animals were divided into two groups: group I (n = 19) underwent the regular LASIK procedure with -10.0 D treatment, without perforation; in group II (n = 23), the cornea was perforated with the excimer laser. Treatment was discontinued once perforation was observed, and the corneal flap was replaced without sutures. Slit-lamp biomicroscopy, photography, and scatterometry were performed preoperatively and at 1 and 2 days, 1 week, and weekly up to 1 month, 2 months, and 3 months postoperatively. Animals were killed at 1 day, 1 week, 1 month, and 3 months postoperatively and processed for light microscopic, electron microscopic, and immunohistochemical examinations. RESULTS: In group I, the corneas remained clear throughout the experiment. In all eyes, the interface was not readily discernable clinically or histologically. Corneal wound healing was accompanied by minimal cell infiltration. Epithelial hyperplasia at the flap edge was noted at 1 week. Myofibroblast activation was found at the epithelial wedge where there was an epithelial basement membrane break. In group II, the anterior chamber was shallow with no iris incarceration at the end of surgery. The corneas were clear (n = 6) or showed mild to moderate edema (n = 12). Corneal edema peaked at 3.6 +/- 5.0 days and subsided thereafter. Corneal wounds healed similarly to those in group I except at the perforation site. The break in Descemet's membrane and endothelium was covered with a fibrin plug on day 1, which resolved thereafter. There was no statistically significant difference in the incidence of postoperative infection (p = 1.0) or flap displacement (p = 0.69) rates between the two treatment groups. The scatterometry index peaked at 2 to 3 weeks postoperatively and was significantly higher in group II than in group I (p < 0.001). CONCLUSIONS: Although corneal perforation during LASIK surgery may interfere with immediate postoperative flap adhesion, corneal wound healing following LASIK perforation may be similar to that after an uncomplicated LASIK procedure.