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Biomedical subjects

S C Tseng

Publications and source records attributed to S C Tseng.

At least 19 recordsLinked to original sources
PubMed2000

[Amniotic membrane transplantation with or without limbal allografts in corneal surface reconstruction in limbal deficiency].

PURPOSE: We examined whether amniotic membrane transplantation (AMT) is useful in preparing the perilimbal stroma to enhance the success of allograft limbal transplantation (ALT). METHODS: Forty-seven eyes of 42 consecutive patients with cytologically proven limbal deficiency (LD) were included in this prospective study. Based on the severity of LD, group A (mild) with 18 eyes received AMT alone, group B (moderate) with 13 eyes received AMT and ALT, and group C (severe) with 16 eyes received AMT, ALT and penetrating keratoplasty. All except for group A received continuous systemic cyclosporin A. RESULTS: Except for the two eyes with atopy, all amniotic membrane-covered surfaces showed rapid epithelialization in 2-4 weeks, reduced inflammation, vascularization and scarring, and became smooth. For the mean follow-up period of 23 months, 38 eyes (82.6%) showed visual improvement, consisting of > or = 6 lines (15 eyes), 4-5 lines (10 eyes), 1-3 lines (13 eyes). Visual improvement was noted in 16/18 eyes (88.9%) in group A, in 10/13 eyes (77%) in group B, and in 12/16 eyes (75%) in group C. In group C corneal graft rejection occurred in 12 of 16 eyes (75%). In group B and C, early reversible limbal allograft rejection was noted in 3 of 29 eyes (10.3%) and a recurrent limbal deficiency was observed in 8 of 29 eyes (27.6%). CONCLUSION: For partial LD with superficial involvement, AMT alone is sufficient and hence superior to ALT because of no need for using cyclosporin A. For total LD, additional ALT is needed and AMT helps reconstruct the perilimbal stroma with reduced inflammation and vascularization, which collectively may enhance ALT success.

Amnion↗
PubMed2000

Amniotic membrane transplantation for acute chemical or thermal burns.

PURPOSE: To determine whether preserved human amniotic membrane (AM) can be used to treat ocular burns in the acute stage. DESIGN: Prospective, noncomparative, interventional case series. PARTICIPANTS: Thirteen eyes from 11 patients with acute burns, 10 eyes with chemical burns and 3 with thermal burns of grades II-III (7 eyes) and grade IV (6 eyes), treated at 7 different facilities. METHODS: Patients received amniotic membrane transplantation (AMT) within 2 weeks after the injury. MAIN OUTCOME MEASURES: Integrity of ocular surface epithelium and visual acuity during 9 months of follow-up. RESULTS: Ten patients were male and one patient was female; most were young (38.2 +/- 10.6 years). For a follow-up of 8.8 + 4.7 months, 11 of 13 eyes (84.63%) showed epithelialization within 2 to 5 weeks (23.7 +/- 9.8 days), and final visual acuity improved > or = 6 lines (6 eyes), 4 to 5 lines (2 eyes), and 1 to 3 lines (2 eyes); only one eye experienced a symblepharon. Eyes with burns of grade II to III showed more visual improvement (7.3 +/- 3 lines) than those with burns of grade IV (2.3 +/- 3.0 lines; P < 0.05, unpaired t test). In the group with grade II or III burns, none had limbal stem cell deficiency. All eyes in the group with grade IV burns did experience limbal stem cell deficiency. CONCLUSIONS: Amniotic membrane transplantation is effective in promoting re-epithelialization and reducing inflammation, thus preventing scarring sequelae in the late stage. In mild to moderate burns, AMT alone rapidly restores both corneal and conjunctival surfaces. In severe burns, however, it restores the conjunctival ocular surface without debilitating symblepharon and reduces limbal stromal inflammation, but does not prevent limbal stem cell deficiency, which requires further limbal stem cell transplantation. These results underscore the importance of immediate intervention in the acute stage of eyes with severely damaged ocular surface. Further prospective randomized studies including a control group are required to determine the effectiveness of AMT in acute chemical and thermal burns of the eye.

Acids↗
PubMed2000

Amniotic membrane transplantation or conjunctival limbal autograft for limbal stem cell deficiency induced by 5-fluorouracil in glaucoma surgeries.

PURPOSE: To determine if human amniotic membrane transplantation or limbal stem cell transplantation is effective to restore the corneal surface with partial or total limbal stem cell deficiency, respectively, caused by 5-fluorouracil (5-FU) toxicity after glaucoma surgeries. METHODS: Partial and total limbal stem cell deficiency was confirmed by impression cytology as the cause of reduced vision and corneal surface breakdown in a 69-year-old man and a 67-year-old man, respectively, who both had received a total of 105 mg 5-FU injections. Amniotic membrane transplantation or conjunctival limbal autograft was performed for corneal surface reconstruction, respectively. RESULTS: For a period of 15 months of follow-up, the visual acuity improved, and their corneal surfaces remained avascular, smooth, and without recurrence of limbal stem cell deficiency. CONCLUSION: Limbal stem cell deficiency can occur as a late complication for patients receiving 5-FU after glaucoma filtering surgeries. Partial limbal stem cell deficiency can be treated with amniotic membrane transplantation alone, whereas limbal transplantation must be considered as an alternative for total limbal stem cell deficiency to restore the corneal surface integrity and vision.

Aged↗
PubMed2000

A spectral-discrimination method for tear-film lipid-layer thickness estimation from fringe pattern images.

Examination of the tear-film lipid layer is often helpful in the prognosis of prospective contact lens patients and contact lens related problems, and in the analysis of symptomatic noncontact lens-wearing patients. In particular, the thickness of the lipid layer is considered to be an informative cue in studying the tear-film stability and uncovering of certain disorders. We propose a method for the accurate estimation of the lipid-layer thickness, exploiting the intensity and color information in Fizeau fringe images. The technique is based on a quantitative measure for discriminating among the spectra associated with different thicknesses. We propose an optical system for imaging the interference patterns, develop a mathematical model based on the physics of the fringe formation and sensing, and describe the calibration of the optical system using this model. The thickness extraction is readily carried out utilizing a lookup table. The proposed method would enable objective evaluation of the lipid layer characteristics, and provide a means for examining the dynamic changes in its thickness and spatial distribution during inter-blink periods.

Algorithms↗
PubMed2000

Amniotic membrane transplantation for severe neurotrophic corneal ulcers.

AIMS: To evaluate whether amniotic membrane transplantation can be an effective alternative treatment for neurotrophic corneal ulcers. METHODS: Amniotic membrane transplantation was performed in 16 eyes of 15 patients with neurotrophic corneal ulcers and vision equal to or worse than 20/200. The neurotrophic state was developed following keratoplasty (four eyes), herpes zoster ophthalmicus (four eyes), diabetes mellitus (four eyes), radiation (two eyes), removal of acoustic neuroma with neuroparalysis (one eye), and herpes simplex keratitis (one eye). RESULTS: During a mean follow up period of 18.8 (SD 13.0) months, one to three layers of amniotic membrane with or without additional membrane as a patch were used for 17 procedures in 16 eyes for persistent neurotrophic corneal ulcers. All but four (76.4%) instances of amniotic membrane transplantation achieved rapid epithelialisation in 16.6 (9.0) days. Of the four eyes showing delayed healing, three eyes healed by tarsorrhaphy, and the remaining one eye with corneal perforation required penetrating keratoplasty and tarsorrhaphy. Two eyes gained vision better than 20/200. The healed corneal surface was accompanied by reduced inflammation. CONCLUSION: Amniotic membrane transplantation can be considered an effective alternative for treating severe neurotrophic corneal ulcers.

Adult↗
PubMed2000

Overexpression of MMP-1 and MMP-3 by cultured conjunctivochalasis fibroblasts.

PURPOSE: To determine whether conjunctivochalasis, denoting redundant, loose, nonedematous inferior bulbar conjunctiva, is associated with increased expression and activity of matrix metalloproteinases (MMPS) over their tissue inhibitors (TIMPs). METHODS: Expression of transcripts and proteins of MMPs, TIMPs, and urokinase plasminogen activator (uPA) by cultured normal human conjunctival and conjunctivochalasis fibroblasts was determined by Northern hybridization, enzyme-linked immunosorbent assay (ELISA), and Western blot analysis, respectively. Gelatin and casein zymography and quantitative collagenase activity assay were performed in the serum-free conditioned media. RESULTS: Compared with normal conjunctival fibroblasts from six subjects, conjunctivochalasis fibroblasts from eight patients showed markedly increased transcript expression of MMP-1 (5- to 32-fold) and MMP-3 (4 to 30-fold), whereas that of MMP-2, TIMP-1, TIMP-2, and uPA was similar between the two groups. Protein levels were increased in the serum-free conditioned media of conjunctivochalasis fibroblasts for MMP-1 (3.5- to 7.6-fold) and MMP-3 (2.3- to 13-fold), determined by ELISA and Western blot analysis. There was increased caseinolytic activity of MMP-3 and collagenolytic activity of MMP-1 (2.2-fold) by conjunctivochalasis fibroblasts, whereas no difference was noted between these two types of fibroblasts in the protein and gelatinolytic activity of MMP-2 or expression of TIMP-1 and TIMP-2 proteins, although that of TIMP-1 transcript was slightly higher in some conjunctivochalasis fibroblasts. No expression of MMP-9 was detected. CONCLUSIONS: Overexpression of MMP-1 and MMP-3 mRNA by conjunctivochalasis fibroblasts is correlated with their increased protein levels and proteolytic activities. Collectively, these data help explain how conjunctivochalasis manifests excessive degradation of the conjunctival matrix and Tenon's capsule.

Blotting, Northern↗
PubMed2000

Suppression of TGF-beta signaling in both normal conjunctival fibroblasts and pterygial body fibroblasts by amniotic membrane.

PURPOSE: When used as an alternative substrate following bare sclera removal of pterygium and other ocular surface diseases, amniotic membrane transplantation can reduce scarring on the reconstructed conjunctival surface. This study was carried out to determine if the amniotic membrane (AM) suppresses the expression of the TGFb signaling system in cultured normal conjunctival (HCF) and pterygial body fibroblasts (PBF). METHODS: HCF and PBF were cultured on AM and plastic wells in serum-containing and serum-free DMEM with or without TGF-beta1. Total RNA was extracted and subjected to Northern hybridization with probes of TGF-beta1, b2 and b3; TGF-beta receptors (TGF- beta R) type I, II and III; a-smooth muscle actin (alpha-SM), b1-integrin, CD44, fibroblast growth factor receptor 1 (FGF-R1/ flg) and platelet-derived growth factor receptor b (PDGFR-beta); and GAPDH as a loading control. MTT assay was used for cell proliferation. RESULTS: Amniotic membrane markedly suppressed the transcript expression of TGF-beta2, b3 and all three types of TGF-beta receptors by both fibroblasts as compared to their cultures on plastic surface. In addition, expression of CD44 transcript was also markedly suppressed while that of b1 integrin, a-SM actin, and FGFR1/flg was mildly suppressed. In contrast, expression of TGF-beta1 and PDGFR-beta remained largely unchanged. The cell proliferation of HCF and PBF grown on AM was also significantly suppressed. CONCLUSIONS: Amniotic membrane matrix uniquely suppresses TGF- beta signaling in both types of fibroblasts. It may also suppress signaling via CD44, b1 integrin and FGFR1/flg. As a result, the phenotype may become less mitogenic, contractile and fibrogenic. These data support in part why amniotic membrane transplantation has an anti-scarring effect for conjunctival surface reconstruction.

Actins↗
PubMed2000

Regulation of collagenase, stromelysin, and urokinase-type plasminogen activator in primary pterygium body fibroblasts by inflammatory cytokines.

PURPOSE: To examine the expression patterns of extracellular matrix degrading enzymes in cultured primary pterygium body fibroblasts activated by cytokines and growth factors potentially derived from ocular surface epithelial cells and tears. METHODS: EGF, TGF-alpha, PDGF-BB, IL-1beta, bFGF, TGF-beta1, TNF-alpha, or IL-6 were added at 10 ng/ml to early passaged primary pterygium body fibroblasts (PBF) or normal human conjunctival fibroblasts (HJF) in a serum-free medium. Expression of transcripts and proteins of MMP-1, MMP-2, MMP-3, MMP-9, TIMP-1, TIMP-2, and uPA was determined by Northern hybridization, ELISA, and Western blotting, respectively. Gelatin and casein zymographies were performed in their serum-free conditioned media with or without enzyme inhibitors to determine the activity of MMP-2 and -3, respectively. RESULTS: IL-1beta and TNF-alpha dramatically increased the mRNA and protein expression of MMP-1 and MMP-3 in cultured PBF when compared to normal HJF and to their nonstimulated counterparts cultured in a serum-free medium. EGF and TGF-alpha also upregulated MMP-3 in PBF when compared to HJF. The transcript levels of MMP-2 were high but stable for the two cell types regardless of the cytokine treatment. Both TIMP-1 and TIMP-2 expressions were not influenced by the cell type or the cytokine treatment. MMP-9 was not expressed in either of these two types of fibroblasts. Both IL-1beta and TNF-alpha induced a significant decrease in uPA expression in PBF, whereas bFGF induced a slight increase in both HJF and PBF. CONCLUSIONS: Chronic inflammatory stimulation by IL-1beta and TNF-alpha, which potentially can be derived from the ocular surface and tears, may be responsible for increased expression of MMPs in cultured PBF. These data have clinical implications on progression of pterygium and recurrence associated with incomplete excision of primary PBF under the influence of ocular surface inflammation. Suppression of intraoperative and postoperative inflammation may be a new strategy to prevent pterygium recurrence.

Blotting, Northern↗
PubMed2000

Modulation of acute inflammation and keratocyte death by suturing, blood, and amniotic membrane in PRK.

PURPOSE: To investigate the role of acute inflammation in keratocyte death, which may influence corneal haze after photorefractive keratectomy (PRK). METHODS: Transepithelial PRK was performed on both eyes of 30 rabbits. Twenty-six rabbits were divided into 4 groups receiving autologous blood, suturing alone, suturing with amniotic membrane graft, or no treatment as the control. Twenty-four hours later, the ablated zone was analyzed for keratocyte death by TdT-dUTP terminal nick-end label (TUNEL) staining and transmission electron microscopy, for polymorphonuclear cell (PMN) infiltration by hematoxylin-eosin staining, and for oxygen radical-induced lipid peroxidation by malondialdehyde immunohistochemistry. The remaining four rabbits were subjected to PRK or mechanical scraping and analyzed immediately or after culturing for 24 hours. RESULTS: Compared with the control group where TUNEL-positive keratocytes were found only in the superficial ablated stroma, blood application or suturing caused more and deeper keratocyte death and PMN infiltration (P: < 0.05). The amniotic membrane graft group had less keratocyte death and PMN than the control or the suture group (P: < 0.05 and P: < 0.01, respectively). There was a strong correlation between keratocyte death and PMN infiltration (P: < 0.01, correlation factor = 0.786). Transmission electron microscopy revealed that the majority of keratocyte death was due to necrosis. Amniotic membrane stroma trapped and prevented PMN infiltration into the stroma. Malondialdehyde-modified antigen was found on the ablated surface and around infiltrated PMN. CONCLUSIONS: Transepithelial PRK causes oxygen radical-mediated lipid peroxidation on the superficial stroma and may contribute to superficial keratocyte death even in the absence of inflammation. Mechanical scraping leads to apoptosis without the participation of inflammation. Keratocyte death by necrosis spreads to the deeper part of the stroma and correlates with additional acute inflammation. Amniotic membrane precludes PMN infiltration and decreases lipid peroxidation and keratocyte death. Future studies are needed to discern whether prevention of inflammation-mediated keratocyte necrosis can reduce unwanted scarring caused by PRK.

Amnion↗
PubMed2000

Regulation of collagenase, stromelysin, and gelatinase B in human conjunctival and conjunctivochalasis fibroblasts by interleukin-1beta and tumor necrosis factor-alpha.

PURPOSE: Overexpression and increased activities of matrix metalloproteinases (MMPs) have recently been reported in cultured conjunctival fibroblasts from patients with conjunctivochalasis. The role of inflammatory cytokines in modulating expression of MMPs, their tissue inhibitors (TIMPs), and urokinase plasminogen activator (uPA) as potential contributors to the pathogenesis of conjunctivochalasis was investigated. METHODS: Interleukin-1beta (IL-1beta) or tumor necrosis factor-alpha (TNF-alpha) was added at 10 ng/ml to a serum-free medium. Expression of transcripts and proteins of MMPs, TIMPs, and uPA by cultured normal human conjunctival and conjunctivochalasis fibroblasts was determined by Northern hybridization, enzyme-linked immunosorbent assay (ELISA) and Western blot analysis, respectively. Gelatin and casein zymographies were performed in serum-free conditioned media with and without the respective enzyme inhibitors. RESULTS: Without challenging the cells, conjunctivochalasis fibroblasts showed mRNA and protein overexpression of MMP-1 and MMP-3 compared with normal conjunctival fibroblasts, which showed minor or no expression of these enzymes. IL-1beta markedly and TNF-alpha to lesser extent increased mRNA and protein expression of MMP-1 and MMP-3 in conjunctivochalasis fibroblasts from 2 subjects when compared with normal conjunctival fibroblasts from 2 subjects and with their nonstimulated counterparts. In conjunctivochalasis fibroblasts and normal conjunctival fibroblasts, TNF-alpha, but not IL-1beta, induced a gelatinolytic activity of MMP-9, which was further confirmed by Western blot analysis and ELISA. Expression of MMP-2, TIMP-1, and TIMP-2 mRNA and protein was not influenced by IL-1beta or TNF-alpha, and no difference was found in the gelatinolytic activity of MMP-2 between both cell types. CONCLUSIONS: Inflammatory cytokines such as IL-1beta and TNF-alpha, which can potentially be derived from the ocular surface and tears, may be responsible for increased expression of MMPs in cultured conjunctivochalasis fibroblasts. Ocular inflammation might be one important denominator in the pathogenesis of conjunctivochalasis.

Blotting, Northern↗
PubMed2000

Choroidal retinal anastomosis in age-related macular degeneration as demonstrated by fluorescein angiography--a case report.

Pathological choroidal retinal anastomosis is relatively rare. It has been described in age-related macular degeneration (AMD) with fibrous scarring or occult pigment epithelial detachment or actively proliferating classic choroidal neovascular membrane (CNV). We report a case of disciform macular scar with the occurrence of a choroidal retinal anastomosis, which directed blood flow from an occult choroidal neovascular membrane into a retinal vein through the fovea in a 52-year-old female with unilateral AMD. Fluorescein angiography (FA) clearly demonstrated the anastomosis.

Choroidal Neovascularization↗
PubMed1999

Amniotic membrane transplantation for symptomatic bullous keratopathy.

OBJECTIVE: To determine whether amniotic membrane transplantation can be used to treat symptomatic bullous keratopathy displaying poor visual potential. METHODS: Amniotic membrane transplantation was performed at 5 centers on 50 consecutive eyes (50 patients) with symptomatic bullous keratopathy and poor visual potential. The underlying causes of bullous keratopathy included aphakia (9 eyes), pseudophakia (19 eyes), failed grafts (9 eyes), and others (13 eyes). RESULTS: During the follow-up period of 33.8 weeks (3-96 weeks) after amniotic membrane transplantation, 43 (90%) of 48 eyes with intolerable pain preoperatively became pain free postoperatively. Among the 5 eyes with residual pain, 3 received repeated amniotic membrane transplantation, 1 required a conjunctival flap for pain relief, and 1 had reduced pain. Epithelial defects in 45 (90%) of 50 eyes created and covered by amniotic membrane healed rapidly within 3 weeks. Only 4 eyes (8%) showed recurrent surface breakdown. Epithelial edema or bullae recurred in a smaller area in 5 eyes (10%) and pseudopterygium developed in 1 eye. CONCLUSION: Amniotic membrane transplantation can be considered as an alternative to conjunctival flaps in alleviating pain, promoting epithelial healing, and preserving cosmetic appearance in patients with symptomatic bullous keratopathy and poor visual potential.

Adult↗
PubMed1999

Suppression of transforming growth factor-beta isoforms, TGF-beta receptor type II, and myofibroblast differentiation in cultured human corneal and limbal fibroblasts by amniotic membrane matrix.

Down-regulation of the transforming growth factor-beta (TGF-beta) signaling system is a strategy for preventing scarring during wound healing. Human corneal and limbal fibroblasts were cultured on the stromal matrix side of preserved human amniotic membrane. The levels of TGF-beta1, beta2, and beta3 and TGF-beta type II receptor transcripts and TGF-beta1 and beta2 proteins were suppressed as early as 8 hr and more dramatically at 24 hr after contact with an amniotic membrane. This suppressive effect was accompanied by down-regulation of alpha-smooth muscle actin, EDA spliced form of fibronectin, and integrin alpha5. It persisted even when challenged by 10 ng/ml TGF-beta1. In contrast with their counterparts grown on plastic or in collagen gel, such suppression in amniotic membrane cultures remained complete after 1 week of culturing. Cells cultured on amniotic membrane showed significantly reduced [3H]-thymidine incorporation compared to cells cultured on plastic and displayed no DNA fragmentation. These results reveal a novel mechanism by which the TGF-beta signaling system, DNA synthesis, and subsequent myofibroblast differentiation can be suppressed by an amnionic membrane matrix. This action explains in part the antiscarring results of amniotic membrane transplantation used for ocular surface reconstruction, a surgical technique applicable to other subspecialties. It may also explain in part why fetal wound healing is scarless.

Adult↗
PubMed1999

Correlation of tear fluorescein clearance and Schirmer test scores with ocular irritation symptoms.

OBJECTIVE: To correlate and compare the Schirmer 1 test and a new method of measuring tear fluorescein clearance with the CytoFluor II fluorometer with the severity of ocular irritation symptoms, clinical signs of meibomian gland disease, corneal fluorescein staining scores, and corneal and conjunctival sensitivity. DESIGN: Case-control study. PARTICIPANTS: Forty patients presenting with a chief complaint of ocular irritation, and 40 asymptomatic control subjects of similar age distribution. INTERVENTION: All subjects completed a symptom questionnaire, a baseline ocular examination, fluorescein clearance test (FCT), and Schirmer 1 test. MAIN OUTCOME MEASURES: The FCT was performed with a CytoFluor II fluorophotometer by measuring the fluorescein concentration in minimally stimulated tear samples collected from the inferior tear meniscus 15 minutes after instillation of 5 microl of 2% sodium fluorescein. Severity of ocular irritation was assessed with a symptom questionnaire. Schirmer 1 test, biomicroscopic meibomian gland evaluation, corneal fluorescein staining score, and corneal and conjunctival sensation scores were assessed with the Cachet-Bonnet anesthesiometer in all subjects. RESULTS: Irritation symptoms correlated with higher log tear fluorescein concentration (symptomatic 3.08 +/- 0.62 units/,microl, normal control 1.89 +/- 0.7 units/microl, P < 0.005) and lower Schirmer 1 test scores (symptomatic 12.6 mm, normal control 22.3 mm, P < 0.005). The FCT showed greater predictive value for identifying ocular irritation than the Schirmer 1 test. A fluorescein concentration of 274 units//microl eliminated 80% of the normal subjects (specificity) and identified 85% of the abnormal subjects (sensitivity). Log of tear fluorescein concentration and the Schirmer 1 test correlated with meibomian gland orifice metaplasia (2.81 +/- 0.78 units/microl and 14.47 +/- 9.53 mm in those with metaplasia vs. 1.83 +/- 0.71 units/microl and 23.14 +/- 7.67 mm in those without metaplasia, P < 0.001) and with the percentage of acinar dropout. Both log of tear fluorescein concentration and the Schirmer 1 test correlated with corneal fluorescein staining (Pearson correlation of 0.394 P < 0.0001 for Schirmer 1 test and 0.312 P < 0.005 for log of tear fluorescein). In addition, log of tear fluorescein and Schirmer 1 test scores correlated with corneal and conjunctival sensation scores (Spearman's rho for corneal sensation: log of tear fluorescein -0.38, P < 0.003, Schirmer 1 test -0.39, P < 0.002, and for conjunctival sensation: log of tear fluorescein -0.391, P < 0.001, Schirmer 1 test -0.23, P < 0.061). CONCLUSIONS: The FCT shows a greater predictive value for ocular irritation than the Schirmer 1 test. It correlates better with age, meibomian gland dysfunction, and decreased corneal and conjunctival sensation. Decreased tear clearance was identified as a risk factor for ocular irritation, even in subjects with normal Schirmer scores. This simple technique may provide new clues into the mechanism and therapy of ocular irritation.

Adult↗
PubMed1999

Vertical root fracture in endodontically versus nonendodontically treated teeth: a survey of 315 cases in Chinese patients.

OBJECTIVE: The purpose of this study was to compare endodontically versus nonendodontically treated teeth with respect to clinical features, including patient age and gender and tooth types of vertical root fractures. STUDY DESIGN: A total of 315 consecutive cases of vertical root fracture occurring in 274 Chinese patients during a 1 3-year period were reviewed. Age and gender, as well as tooth type and root distribution of vertical root fractures, were presented and compared in endodontically versus nonendodontically treated teeth. RESULTS: Most patients (87%) had 1 fractured tooth; the others had 2 or 3 fractured teeth. Of all vertical root fractures, 40% occurred in nonendodontically treated teeth. In comparison with those in endodontically treated teeth, vertical root fractures in nonendodontically treated teeth tended to occur in patients with a higher mean age (55 years vs. 51 years) and were more frequent in male patients (78% vs. 58%). Vertical root fractures occurred in nonendodontically treated teeth more often in molars (84% vs. 53%), less often in premolars (16% vs. 33%), and seldom in anteriors (1 tooth vs. 27 teeth). CONCLUSIONS: Vertical root fractures in nonendodontically treated teeth are not uncommon and comprise a large proportion of such fractures in Chinese patients. Differences between endodontically and nonendodontically treated teeth in patient age and gender, as well as in tooth types of vertical root fractures, were demonstrated.

Adult↗
PubMed1999

Differential expression and regulation of TGF-beta1, TGF-beta2, TGF-beta3, TGF-betaRI, TGF-betaRII and TGF-betaRIII in cultured human corneal, limbal, and conjunctival fibroblasts.

PURPOSE: We have reported that three patterns of cytokine expression are potentially involved between epithelia and fibroblasts of the human ocular surface. The TGF-beta family is a prototypical fibrogenic cytokine responsible for fibroblast activation in wound healing. We investigated how the TGF-beta family is differentially expressed and regulated in cultured human corneal, limbal and conjunctival fibroblasts. METHODS: Human corneal (HCF), limbal (HLF) and conjunctival fibroblast (HJF) were cultured in DMEM-10% FBS until confluence and switched to serum-free DMEM-ITS for 48 h before adding 10 ng/ml of each of eight cytokines for 4 h in three separate experiments. Total RNA was isolated and subjected to Northern hybridization with GAPDH as a control. ELISA was used to determine TGF-beta1 and TGF-beta2 proteins in the media. RESULTS: All three isoforms of TGF-beta and three types of TGF-betaR were expressed by HCF, HLF and HJF. Expression of TGF-beta1 mRNA was strongest and upregulated by the three TGF-betas in all three types of fibroblast. PDGF-BB and TGF-alpha slightly increased TGF-beta1 mRNA. TGF-betas also upregulated TGF-beta3 mRNA in HJF. TGF-betaRI mRNA was the only receptor upregulated by TGF-betas. TGF-betaRII and TGF-betaRIII mRNA were not regulated by all cytokines tested. CONCLUSIONS: TGF-betas auto-induction is the major mechanism upregulating TGF-beta1 expression. Promotion of TGF-beta3 by the TGF-betas may have a special role in HJF. Differential expression and regulation of TGF-betas and TGF-betaRs suggest that each TGF-beta isoform may have specific functions in different ocular surface fibroblasts. No cytokine tested can downregulate TGF-beta1 and the TGF-betaRs.

Adult↗