Ropivacaine has the potential to relieve PM2.5‑induced acute lung injury

Ropivacaine is a commonly used local anesthetic in the clinic due to its low toxicity to the cardiovascular system or central nervous system, good tolerance and high clearance rate. The present study intended to investigate the effect of ropivacaine on PM2.5-induced acute lung injury (ALI) and reveal the underlying mechanism. After ropivacaine exposure, cell viability, oxidative stress and inflammation in PM2.5-induced BEAS-2B cells were assessed by Cell Counting Kit-8 and DCFH-DA staining, corresponding commercial kits and ELISA, respectively. The effects of ropivacaine on the expression of MMP9 and MMP12 and the proteins related to NLRP3/Caspase-1 signaling were then determined by western blot and reverse transcription-quantitative PCR analyses. In addition, NLR family pyrin domain containing 3 (NLRP3) agonist monosodium urate (MSU) was used to treat BEAS-2B cells followed by ropivacaine treatment and the effects on the above-mentioned cellular behaviors were determined again. The results indicated that the viability of BEAS-2B cells was decreased after PM2.5 induction, accompanied by aggravated oxidative stress and inflammation. However, ropivacaine alleviated oxidative stress and inflammation in PM2.5-induced BEAS-2B cells in a dose-dependent manner. Ropivacaine was also indicated to decrease the expression levels of NLRP3/Caspase-1 signaling-related proteins in PM2.5-induced BEAS-2B cells. Furthermore, cell viability was decreased, while oxidative stress and inflammatory response were aggravated, in PM2.5-induced BEAS-2B cells treated with MSU. In summary, the present results implied that ropivacaine exerted protective effects on PM2.5-induced ALI, and this effect may be related to NLRP3/Caspase-1 signaling.

Hydronephrosis caused by intrauterine contraceptive device migration: three case reports with literature review

Translocation of intrauterine contraceptive device (IUD) from the uterus rarely occurs, which can lead to serious complications. Here the authors reported three cases of IUD migration from into the ureter, bladder, and peritoneal cavity that caused hydronephrosis, respectively. All the three patients received minimally invasive surgeries and recovered.

[A preliminary evaluation and discussion on the significance of the medical bamboo slips Ci shu (Needling Methods) unearthed from a Han tomb in the Mount. Laoguan, Chengdu]

The compilation of medical bamboo slips, Ci shu(Needling Methods), which was unearthed from a Han tomb in Mt. Laoguan, is a monograph dealing exclusively with the principles of clinical acupuncture manipulations with 40 acupuncture prescriptions, being the earliest unearthed work with documented standard methods of acupuncture manipulations and acupuncture prescriptions in China. The chapter Zhen fang (Acupuncture Prescriptions) is the earliest summary of standardized acupoint prescriptions up to now in China, which is of great significance to clinical practice directly derived from ancient clinical performance of acupuncture. The chapter Zhen fang of the book Ci shu is also one of the earliest ancient clinical reports archiving the acupoint. This may provide invaluable perspectives to the study of the conceptualization, origination, development, formation of theoretical system, and clinical application of acupoints.

Electromagnetic interference reduction design of alternating integrator for EAST

An alternating integrator has been designed for the Experimental Advanced Superconducting Tokamak that is intended for long pulse operation of up to 1000 s. The electromagnetic operating environment for the device is so complex that it could affect the performance of the integrator. The new integrator system is carefully designed and actualized based on specific reduced electromagnetic interference requirements, which were formulated based on consideration of processing of the input signals, the isolation properties, and the circuit board layout and grounding. The developed integrator shows excellent electromagnetic compatibility and low-drift properties.

Three branches of phospholipase C signaling pathway promote hepatocyte growth in rat liver regeneration

In general, the phospholipase C (PLC) signaling pathway is involved in many physiological activities, including cell growth. However, little is known regarding how the PLC signaling pathway participates in regulating hepatocyte (HC) growth during liver regeneration (LR). To further explore the influence of the PLC signaling pathway on HCs at the cellular level, HCs of high purity and vitality were isolated using Percoll density-gradient centrifugation after partial hepatectomy. The genes of the PLC signaling pathway and target genes of transcription factors in the pathway were obtained by searching the pathways and transcription factor databases, and changes in gene expression of isolated HCs were examined using the Rat Genome 230 2.0 Microarray. The results suggested that various genes involved in the pathway (including 151 known genes and 39 homologous genes) and cell growth (including 262 known genes and 37 homologous genes) were associated with LR. Subsequently, the synergetic effect of these genes in LR was analyzed using a mathematical model (Et) according to their expression profiles. The results showed that the Et values of G protein-coupled receptor/PLC, integrin/PLC, and growth factor receptor/PLC branches of the PLC pathway were all significantly strengthened during the progression and termination phases of LR. The synergetic effect of target genes, in parallel with target gene-related cell growth, was also enhanced during whole rat LR, suggesting the potential positive effect of PLC on HC growth. The present data indicate that the PLC signaling pathway may promote HC growth through 3 mechanisms during rat LR after partial hepatectomy.

Development of an alternating integrator for magnetic measurements for experimental advanced superconducting tokamak

A high-performance integrator is one of the key electronic devices for reliably controlling plasma in the experimental advanced superconducting tokamak for long pulse operation. We once designed an integrator system of real-time drift compensation, which has a low integration drift. However, it is not feasible for really continuous operations due to capacitive leakage error and nonlinearity error. To solve the above-mentioned problems, this paper presents a new alternating integrator. In the new integrator, the integrator system of real-time drift compensation is adopted as one integral cell while two such integral cells work alternately. To achieve the alternate function, a Field Programmable Gate Array built in the digitizer is utilized. The performance test shows that the developed integrator with the integration time constant of 20 ms has a low integration drift (<15 mV) for 1000 s.

[Cloning and analysis of a novel gene encoding N-terminal acetyltransferase subunit]

N-terminal acetylation is the most common modification in eukaryotic proteins, affecting stability and activity of proteins. NatA is one of the N-terminal acetytransferases in yeast. It is composed of two subunits, NAT1 and ARD1. Defect in one of them leads to loss of activity of NatA. Null mutant of NAT1 in yeast exhibits a variety of phenotypes, including depression of a silent mating type locus (HML), failing to enter G(0) in poor nutrient situations and chromosomes instability. Based on homology of NAT1 between yeast and other organisms, the full-length CDS (coding sequence) of HNAT1 was cloned and sequenced. Result of in situ hybridization in testis of rat showed that expression of NAT1 was high and its expression was different in different phases of spermatogenesis. The gene may play an important role in spermatogenesis.

Proinflammatory chemokine induction in keratocytes and inflammatory cell infiltration into the cornea

PURPOSE

To determine the effect of interleukin (IL)-1alpha and tumor necrosis factor (TNF)-alpha on cytokine, chemokine, and receptor expression in corneal stromal cells; the effect of corneal scrape injury on monocyte chemotactic and activating factor (MCAF) expression and monocyte-macrophage influx into the stroma; and the effect of MCAF and granulocyte colony-stimulating factor (G-CSF) microinjection on inflammatory cell infiltration into the stroma.

METHODS

Gene array technology was used to evaluate changes in cytokine, chemokine, and receptor gene expression in stromal fibroblasts in response to IL-1alpha and TNFalpha. Expression of MCAF mRNA and protein was monitored with an RNase protection assay and Western blot analysis, respectively. Keratocyte MCAF protein expression in the rabbit cornea was detected with immunocytochemistry. After epithelial scrape injury, monocytes-macrophages were detected in rabbit corneas, by immunocytochemistry for monocyte-macrophage antigen. Inflammatory cell infiltration after MCAF and G-CSF microinjection into the stroma of mouse corneas was monitored with hematoxylin and eosin staining.

RESULTS

IL-1alpha or TNFalpha upregulated the expression of several proinflammatory chemokines in stromal fibroblasts in culture. These included G-CSF, MCAF, neutrophil-activating peptide (ENA-78), and monocyte-derived neutrophil chemotactic factor (MDNCF). MCAF mRNA upregulation was confirmed by RNase protection assay, and MCAF protein was detected by Western blot analysis. MCAF protein was detected in keratocytes at 4 hours and 24 hours after epithelial injury, but not in keratocytes in the unwounded cornea. Corneal epithelial injury triggered the influx of monocytes-macrophages into the corneal stroma in the rabbit. Microinjection of MCAF and G-CSF into mouse cornea resulted in the influx of monocytes-macrophages and granulocytes, respectively, into the stroma.

CONCLUSIONS

Proinflammatory chemokine induction in keratocytes is mediated by IL-1alpha and TNFalpha. The proinflammatory chemokines produced by the keratocytes probably trigger the influx of inflammatory cells into the stroma after epithelial injury associated with corneal surgery, contact lenses, or trauma.

Rapid restoration of visual pigment and function with oral retinoid in a mouse model of childhood blindness

Mutations in the retinal pigment epithelium gene encoding RPE65 are a cause of the incurable early-onset recessive human retinal degenerations known as Leber congenital amaurosis. Rpe65-deficient mice, a model of Leber congenital amaurosis, have no rod photopigment and severely impaired rod physiology. We analyzed retinoid flow in this model and then intervened by using oral 9-cis-retinal, attempting to bypass the biochemical block caused by the genetic abnormality. Within 48 h, there was formation of rod photopigment and dramatic improvement in rod physiology, thus demonstrating that mechanism-based pharmacological intervention has the potential to restore vision in otherwise incurable genetic retinal degenerations.

Identification of a locus for disseminated superficial actinic porokeratosis at chromosome 12q23.2-24.1

Disseminated superficial actinic porokeratosis is an autosomal dominant cutaneous disorder characterized by many uniformly small, minimal, annular, anhidrotic, and keratotic lesions. The genetic basis for this disease is unknown. Using a genomewide search in a large Chinese family, we identified a locus at chromosome 12q23.2-24. 1 responsible for disseminated superficial actinic porokeratosis. The fine mapping study indicates that the disseminated superficial actinic porokeratosis gene is located within a 9.6 cM region between markers D12S1727 and D12S1605, with a maximum two-point LOD score of 20.53 (theta = 0.00) at D12S78. This is the first locus identified for a genetic disease where the major phenotype is porokeratosis. The study provides a map location for isolation of a gene causing disseminated superficial actinic porokeratosis.

Experimental transplantation of cultured human limbal and amniotic epithelial cells onto the corneal surface

PURPOSE

Tissue-cultured corneal epithelial transplantation is a novel procedure that uses tissue-cultured epithelial cells to restore severely damaged ocular surfaces. In this study, we used tissue-cultured human limbal and amniotic epithelial cells as donor cells to investigate the feasibility of this procedure for reestablishment of a damaged ocular surface in experimental conditions.

METHODS

Primary human limbal epithelial cultures were established from banked limbal tissue. Amniotic epithelial cells were isolated from serologically screened human placenta and maintained in a specialized nutrient medium. Suspended cells (5 x 10(5)/ml) were seeded onto the concave surface of collagen corneal shields and incubated at 37 degrees C for 2-3 days. These cell-covered shields were then placed on a denuded stromal surface in organ culture and on New Zealand albino rabbit ocular surfaces that had the native epithelium previously removed. Specimens were collected 24, 48, 72, and 96 h later from organ-cultured corneal buttons and recipient animals, processed, and evaluated histologically.

RESULTS

The cells grown on the collagen shield were spread uniformly and unpolarized after 48 h in culture. They were repolarized and tightly adhered to the recipient corneal stroma 24 h after transplantation, as demonstrated by formation of cell-substrate hemidesmosomes (HDs) and donor-specific antigen immunostaining. The donor cells were retained in six of 15 rabbits receiving limbal cells and four of 12 rabbits receiving amniotic cells for as long as 10 days after surgery.

CONCLUSION

Cultured human limbal and amniotic epithelial cells can be successfully transplanted onto a denuded corneal surface where they adhere tightly to underlying stroma by hemidesmosomes.

Epithelial injury induces keratocyte apoptosis: hypothesized role for the interleukin-1 system in the modulation of corneal tissue organization and wound healing

The purpose of this study was to determine the role of programmed cell death (apoptosis) in the disappearance of keratocytes beneath an epithelial debridement wound in the cornea and to investigate a potential role of interleukin-1 (IL-1) in induction of apoptosis in stromal fibroblasts in vitro and keratocytes in vivo. Keratocyte and stromal fibroblast cell morphology was examined in wounded and unwounded mouse corneas using transmission electron microscopy. Nuclear DNA fragmentation was detected with the TUNEL assay for 3'-hydroxyl DNA ends. The effect of IL-1 on keratocytes in vivo was determined by microinjection of IL-1 alpha into the central corneal stroma via a limbal entry site. The in vitro effects of interleukin-1 alpha (IL-1 alpha) and interleukin-1 beta (IL-1 beta) were determined with primary cultures of human corneal stromal and dermal fibroblasts. Cell shrinkage, blebbing with formation of membrane bound bodies, condensation and fragmentation of the chromatin, and DNA fragmentation, consistent with apoptosis were detected in anterior stromal keratocytes after epithelial scrape wounds. Thus, disappearance of keratocytes from the underlying stroma following epithelial debridement is mediated by apoptosis. Microinjection of IL-1 alpha into the central stroma of the mouse cornea caused a redistribution of keratocytes in the stroma via apoptosis and, possibly, negative chemotaxis. IL-1 alpha and IL-1 beta induced apoptosis in corneal stromal and dermal fibroblasts in vitro. The epithelial/endothelial-stromal IL-1 system may mediate corneal tissue organization and responses to mechanical- and pathogen-induced injury through induction of keratocyte apoptosis. Keratocyte apoptosis is likely an initiating event in wound healing following corneal surgery. We hypothesize that derangement's in this system may have a role in the pathogenesis of keratoconus and other diseases of the cornea.

The effect of oral immunization on corneal allograft survival

The present study examined the potential of orally induced tolerance for preventing immunological rejection of corneal allografts. Orthotopic corneal allografts were transplanted from either C3H (MHC + multiple minor H-mismatched) or NZB (multiple minor H-mismatched only) donors to CB6F1 recipients on day 0. Tissue cultured corneal epithelial and endothelial cells from relevant donor strains were administered orally from day -14 to day -4 on a daily basis, The incidence of graft rejection, graft mean survival time (MST), and alloimmune responses, and the antigen specificity of induced tolerance were studied. Oral immunization induced a remarkable tolerance such that only 55% of the orally immunized hosts rejected their fully allogeneic corneal grafts (MST = 43 days) compared with 100% rejection (MST = 18 days) in normal controls. Likewise, rejection of MHC-matched, multiple minor H-mismatched corneal grafts fell from 80% in untreated controls to 36% in orally immunized hosts. Oral immunization was effective in desensitizing previously immunized hosts. Rejection of MHC-matched, multiple H minor-mismatched corneal allografts fell from 93% in preimmune, unfed hosts to 36% in preimmune, orally tolerized mice. Thus, oral immunization is a safe and effective method for desensitizing high-risk, preimmune hosts and promoting corneal allograft survival.

Depletion of donor-derived Langerhans cells promotes corneal allograft survival

A mouse model of penetrating keratoplasty was used to evaluate the efficacy of ultraviolet radiation (UVR) and hyperbaric oxygen (HBO) treatments in depleting corneal Langerhans cells (LC) and promoting corneal allograft survival. The presence of donor-derived LC dramatically increased the immunogenicity and rejection rate of corneal allografts. Rejection increased from 40% in LC- corneal grafts to 80% in grafts containing donor-derived LC. Pretreatment with either HBO or UVR resulted in a sharp decrease in both the incidence and tempo of rejection for grafts containing donor LC, but neither procedure affected the fate of LC- corneal allografts. UVR-treatment abolished the immunogenicity of LC+ grafts. UVR-treated orthotopic grafts failed to elicit either cytotoxic T lymphocyte (CTL) or delayed-type hypersensitivity (DTH) responses that were any greater than naive control mice. The results suggest that purging corneal allografts of stray donor-derived LC might improve corneal allograft survival in high-risk patients without jeopardizing the functional integrity of the graft.

Expression of E6/E7 or SV40 large T antigen-coding oncogenes in human corneal endothelial cells indicates regulated high-proliferative capacity

PURPOSE

Human corneal endothelial cells are thought to have limited capacity for proliferation. Little is known about the mechanisms that regulate the proliferation of these cells. The authors introduced oncogenes into human corneal endothelial cells to modulate proliferation. In addition, they sought to establish cell lines to facilitate study of human corneal endothelial cells.

METHODS

Early-passage human corneal endothelial cells were transduced with disabled retrovirus (pLXSN16E6/E7) coding for the human papilloma virus type 16 transforming oncoproteins E6 and E7. Early-passage cells were also stably transfected by electroporation with the pMTV-D305 plasmid vector, in which SV40 large T antigen (SV40 LTAg) mRNA expression is positively regulated by the mouse mammary tumor virus promoter. Expression of E6/E7 mRNA or SV40 LTAg mRNA in cell lines was monitored with the polymerase chain reaction. SV40 LTAg protein expression was detected by immunocytology and Western blot analysis.

RESULTS

Human corneal endothelial cells were efficiently infected with disabled retrovirus coding for E6/E7, and seven strains of cells have continued active proliferation for more than 50 population doublings (PD) (< 8 control PD). E6/E7 mRNA was expressed by each cell strain. E6/E7 transformed cells proliferate rapidly and form a monolayer of cells with a high degree of contact inhibition. Transfection with pMTV-D305 is less efficient, and only a single strain was developed. pMTV-D305-transfected endothelial cells (dexamethasone induced) proliferated at a lower rate than E6/E7-transduced cells or cells transfected with a vector (pSV3neo) in which SV40 LTAg is constitutively regulated. In the absence of dexamethasone, the proliferation of pMTV-D305-transfected cells was even slower, but cells continued to produce SV40 LTAg mRNA and protein. The latter results indicated that SV40 LTAg mRNA continued to be synthesized at significant levels in pMTV-D305-transfected cells in the absence of the inducer dexamethasone.

CONCLUSIONS

This study suggests that human corneal endothelial cells have a high capacity for proliferation. Thus, cell division is normally controlled in human corneal endothelial cells by poorly characterized, but efficient, mechanisms. Because the E6 and E7 proteins, as well as the SV40 large T antigen, specifically bind to and interfere with the activity of the retinoblastoma (RB) and p53 tumor suppressor proteins, our results suggest that these proteins have critical roles in regulating the proliferation of human corneal endothelial cells.

Effect of epidermal growth factor, hepatocyte growth factor, and keratinocyte growth factor, on proliferation, motility and differentiation of human corneal epithelial cells

We sought to determine the effects of exogenous epidermal growth factor (EGF), heparin-binding EGF (HB-EGF), transforming growth factor alpha (TGF-alpha), single-chain precursor hepatocyte growth factor (SC-HGF), double-chain mature HGF (DC-HGF), and keratinocyte growth factor (KGF) on proliferation, motility, and differentiation of first passage cultures of human corneal epithelial cells in serum-free chemically defined medium. The effect of EGF, HB-EGF, TGF-alpha, SC-HGF, DC-HGF, KGF or combinations of the growth factors on proliferation was measured by counting cells present after 3 weeks of culture and by immunostaining for the cell-cycle-specific nuclear proliferation antigen Ki-67. The effect of the factors on epithelial cell motility was assessed by morphometric analysis of photographs of cells migrating from confluent islands of cells. The effect of growth factors on differentiation of epithelial cells were determined by immunostaining epithelial cell islands for the keratin K3 and by Western blotting for keratin K3. EGF, alone or in combination with KGF and SC-HGF, significantly stimulated motility of epithelial cells at the periphery of confluent islands of cells and induced an elongated cell morphology. TGF-alpha, HB-EGF and DC-HGF produced motility effects similar to EGF. There was diminished proliferation of the migrating cells in response to EGF, HB-EGF, TGF-alpha or DC-HGF, while non-migrating epithelial cells in the center of confluent islands continued to proliferate in response to the growth factors. EGF, HB-EGF, TGF alpha or DC-HGF inhibited expression of the differentiation-related marker keratin K3 in epithelial cells, both at the edge and at the center of the islands. KGF stimulated proliferation of corneal epithelial cells at low density and in confluent islands of cells. KGF did not affect expression of keratin K3 or migration of epithelial cells. SC-HGF had no effect on corneal epithelial cells. These results indicate that the effects of EGF, HB-EGF, TGF-alpha and DC-HGF on corneal epithelial cell proliferation, motility and differentiation vary from those of KGF and SC-HGF. EGF, HB-EGF, TGF-alpha and DC-HGF induced changes in epithelial cell morphology and motility in cells plated at low cell density or in cells located at the edge of a confluent island. Thus, these effects appear to be dependent on the extent of cell-cell contact. The inhibitory effect of EGF, HB-EGF, TGF-alpha or DC-HGF on corneal epithelial cell differentiation, however, is independent of cell density.(ABSTRACT TRUNCATED AT 400 WORDS)

Epidermal growth factor, transforming growth factor alpha, transforming growth factor beta, acidic fibroblast growth factor, basic fibroblast growth factor, and interleukin-1 proteins in the cornea

The purpose of this study was to determine whether epidermal growth factor (EGF), EGF receptor, transforming growth factor alpha (TGF-alpha), transforming growth factor beta (TGF-beta), acidic fibroblast growth factor (acidic-FGF), basic fibroblast growth factor (basic-FGF), and interleukin-1-alpha (IL-1-alpha) proteins were present in cultures of human corneal cells and/or in sections of human corneal tissue. Immunohistochemistry was performed on human corneal sections. Immunofluorescent cell staining was used to evaluate corneal epithelial, stromal fibroblast, and endothelial cells in primary culture. Basic-FGF production was evaluated in culture cells using immunoprecipitation. EGF, TGF-alpha, TGF-beta-1, and IL-1-alpha were detected by immunohistochemistry in cells in all three layers of the cornea. EGF receptor and acidic FGF were detected by immunohistochemistry in epithelial and endothelial cells, but not in stromal fibroblast cells. Differences in distribution of the growth factors were noted within individual layers of the cornea. EGF and basic-FGF proteins were detected in all three predominant cell types of the cornea using immunocytology. IL-1-alpha protein was detected by immunocytology in corneal epithelial and endothelial cells, but not stromal fibroblasts. Immunoprecipitation confirmed the production of basic-FGF in all three cell types. IL-1-alpha protein detection in the corneal stroma by immunohistology, but not by immunocytology in first passage stromal fibroblasts, suggests that IL-1-alpha may localize to the corneal stroma after production by corneal epithelial and/or endothelial cells.

Glucocorticoid receptor and interleukin-1 receptor messenger RNA expression in corneal cells

Interleukin-1 receptor and glucocorticoid receptor messenger ribonucleic acid (RNA) sequences coding for the corresponding proteins were detected in corneal epithelium, stromal fibroblast, and endothelial cells using the polymerase chain reaction and hot blotting. Identification of interleukin-1 receptor mRNA in each of the three major cell types of the cornea suggests that interleukin-1 alpha has autocrine and/or paracrine roles in the cornea, since previous studies have found that interleukin-1 alpha mRNA is produced in corneal epithelial, stromal fibroblast, and endothelial cells. Further investigation is needed to determine the functions regulated by the interleukin-1 receptor and glucocorticoid receptor in the cornea and the role of each in corneal wound healing.

Clinical and diagnostic use of in vivo confocal microscopy in patients with corneal disease

BACKGROUND

The purpose of this article is to introduce the practicing ophthalmologist to the optical principles and images produced by a tandem scanning confocal microscope (recently approved by the Food and Drug Administration for general clinical use). The tandem scanning confocal microscope allows real-time viewing of structures in the living cornea at the cellular level in four dimensions (x, y, z, and time).

METHODS

Nine patients (2 males, 7 females), ranging in age from 7 to 52 years, were examined. Images were recorded on super VHS videotape, digitized and processed on a computer workstation, and photographed for presentation.

RESULTS

Two-dimensional (x, y) 400 x 400-microns images (9-microns z-axis thickness) are presented for normal corneal structures and for the clinical conditions of herpetic keratitis, wound healing after myopic excimer ablation, Acanthamoeba infection, corneal dystrophies (granular, Reis-Buckler), contact lens abrasion, and the irido-corneal endothelial syndrome.

CONCLUSION

Clinical confocal microscopy has the unique potential of providing noninvasive assessment of corneal injury and disease at the cellular level that is not available currently from other technologies.

Hepatocyte growth factor, keratinocyte growth factor, their receptors, fibroblast growth factor receptor-2, and the cells of the cornea

PURPOSE

The purpose of this study was to determine whether messenger RNA coding for hepatocyte growth factor (HGF), HGF receptor (MET), keratinocyte growth factor (KGF), KGF receptor, and fibroblast growth factor (FGF) receptor-2 were produced in primary cultures of human corneal epithelial, stromal fibroblast, and endothelial cells, as well as ex vivo corneal epithelium, endothelial cells transfected with the SV40 large T antigen, and control embryonic lung fibroblasts. The effects of exogenous HGF and KGF, compared to epidermal growth factor, on the proliferation of first passage corneal cells were also examined.

METHODS

Polymerase chain reaction was used to amplify complementary DNA for each modulator from each cell type. Hot blotting was used to demonstrate the specificity of amplification products. Proliferation of first passage corneal epithelial, stromal fibroblast, and endothelial cells in response to varying concentrations of HGF, KGF, and epidermal growth factor was measured.

RESULTS

Specific amplification products for messenger RNA coding for each modulator were detected in each corneal cell type, although very low levels of HGF and KGF messenger RNA appeared to be present in corneal epithelial cells relative to stromal fibroblasts and corneal endothelial cells. Amplification products that may have been derived from alternative transcripts were detected for several of the modulators. HGF and KGF stimulated proliferation in a dose-response manner in first passage corneal epithelial and endothelial cells, but not stromal fibroblast cells.

CONCLUSIONS

Human corneal epithelial, stromal fibroblasts, and endothelial cells produce messenger RNA coding for HGF and KGF, although low levels appear to be present in the epithelial cells. All three major cell types of the cornea produce messenger RNA coding for HGF receptor, KGF receptor, and FGF receptor-2. The proliferation of human corneal epithelial and endothelial cells, but not stromal fibroblasts, was stimulated by exogenous HGF and KGF. HGF and KGF likely have intracrine, autocrine, and/or paracrine functions in the cornea. Exogenous HGF and KGF may be useful in corneal preservation and for regulating corneal wound healing.

Extended life of human corneal endothelial cells transfected with the SV40 large T antigen

PURPOSE

To transfect human corneal endothelial cells with a plasmid vector coding for the SV40 large T antigen to extend the life of the cells in culture.

METHODS

Human corneal endothelial cells were transfected with the SV40 large T antigen-coding plasmid pSV3neo using the electroporation method. Transfected and control cells were propagated in culture until senescence. Polymerase chain reaction and immunofluorescence were used to demonstrate messenger RNA and protein, respectively, for the Simian virus 40 large T antigen in the transfected cells. Polymerase chain reaction and hot blotting were used to demonstrate messenger RNA coding for several growth factors and receptors in transfected and control cells.

RESULTS

The transfected cells continued to proliferate to 38 passages (more than 120 population doublings) in culture (control cells, 8 population doublings). Transfected cells, but not control cells, expressed messenger RNA coding for the Simian virus 40 large T antigen. Similarly, immunofluorescent staining with monoclonal antibodies demonstrated that the Simian virus 40 large T antigen protein was present in the nucleus of the transfected cells. Transfected cells were shown to produce messenger RNA coding for epidermal growth factor, epidermal growth factor receptor, basic fibroblast growth factor, fibroblast growth factor receptor-1, interleukin-1 alpha, the interleukin-1 receptor, transforming growth factor beta-1, and the glucocorticoid receptor. Qualitative expression of the messenger RNA coding for each of these modulators was similar in proliferating primary corneal endothelial cells and proliferating or confluent transfected corneal endothelial cells.

CONCLUSIONS

In culture, the life of human corneal endothelial cells transfected with a plasmid vector coding for the Simian virus 40 large T antigen is extended. This study suggests that human corneal endothelial cells have the capacity for extensive proliferation, but the proliferation of untransfected cells is regulated through mechanisms that have not yet been characterized.

Fibroblast growth factor-1 receptor messenger RNA expression in corneal cells

The polymerase chain reaction (PCR) and hot-blotting methods were used to identify fibroblast growth factor (FGF) receptor-1-specific messenger ribonucleic acid (mRNA) sequences in cDNA samples prepared from human corneal endothelial cell cultures with proliferative and senescent morphology, an ex vivo corneal epithelium sample, two primary corneal epithelial cell cultures, two third-passage corneal epithelial cell cultures, and two stromal fibroblast cultures. The PCR primers used in this study distinguished mRNAs coding for three aminoterminal motifs (alpha, beta, and gamma) of the FGF receptor-1 that are derived by alternative splicing from a single genomic sequence. Messenger RNA molecules coding for FGF receptor-1 amino-terminal motif were detected in corneal endothelial and epithelial cells. The alpha and beta amino-terminal motif, but not the gamma amino-terminal motif, mRNAs were detected in stromal fibroblasts. The gamma motif lacks a known signal sequence for membrane translocation and is thought to represent an intracellular form of the FGF receptor-1. Identification of mRNA coding for FGF receptor-1 along with the previous identification of basic FGF mRNA and protein in corneal endothelial, epithelial, and stromal fibroblast cells suggests an autocrine and/or paracrine role for basic FGF in the physiology of the cornea.

EGF, basic FGF, and TGF beta-1 messenger RNA production in rabbit corneal epithelial cells

The polymerase chain reaction (PCR) was used to demonstrate that rabbit corneal epithelial cells produce messenger RNAs coding for epidermal growth factor (EGF), basic fibroblast growth factor (FGFb), and transforming growth factor beta-1 (TGF beta 1) ex vivo and in primary culture. EGF, FGFb, and TGF beta 1 mRNAs were detected in central and peripheral ex vivo epithelial tissue in wounded and unwounded rabbit corneas. Southern blots of the PCR products were probed with oligonucleotides to demonstrate that the appropriately sized amplification products were specific. These results suggest that corneal epithelial cells produce growth factors that may have autocrine or paracrine effects on epithelial cells, and possibly other cells of the cornea. The functions, if any, performed by these growth factors in corneal epithelial wound healing are yet to be elucidated.

EGF, EGF receptor, basic FGF, TGF beta-1, and IL-1 alpha mRNA in human corneal epithelial cells and stromal fibroblasts

We sought to determine whether human corneal epithelial cells and stromal fibroblasts synthesize messenger RNAs (mRNA) coding for epidermal growth factor (EGF), EGF receptor, basic fibroblast growth factor (basic FGF), transforming growth factor-beta 1 (TGF-beta 1), and interleukin-1 alpha (IL-1 alpha). Total cellular RNA was extracted from cultured stromal fibroblasts and ex vivo and cultured corneal epithelial cells. Oligo dt-primed complementary DNA (cDNA) was synthesized from each RNA sample. The polymerase chain reaction (PCR) was used to amplify sequences for EGF, EGF receptor, basic FGF, TGF-beta 1, IL-1 alpha, and beta actin from cDNA samples from each cell type. Southern blots of the PCR products were probed with oligonucleotides complementary to internal sequences within each of the amplified products. The amplification products were shown to be specific. For each modulator, the amplification product of the expected size was identified with at least one specific, alternative amplification product. The alternative splicing products suggest that there may be alternative mRNA splicing for each of the modulators studied. Differences were noted in the IL-1 alpha specific amplification products in stromal fibroblasts compared to corneal epithelial cells. EGF and EGF receptor mRNA production in human corneal epithelial cells and stromal fibroblasts suggest an autocrine role for EGF in the physiology of each of these cell types.

A pig model of Acanthamoeba keratitis: transmission via contaminated contact lenses

A model of contact lens-induced Acanthamoeba keratitis was developed in Yucatan micropigs. Pigs fitted with parasite-laden soft contact lenses developed corneal infections that clinically and histopathologically mimicked the human counterpart. Three distinct stages of disease became apparent and were categorized as: acute, condensed infiltrate, and resolution stages. Viable parasites were isolated from corneal scrapings and smears were taken during the acute and condensed infiltrate stages. In addition, cysts could be identified deep within the stroma of histological specimens taken during the resolution stages. The characteristic dense, white ring-like infiltrates, stroma edema, keratic precipitates, and the chronic nature of the infections were similar to those observed in human Acanthamoeba keratitis. Histopathological examination of infected corneas revealed extensive neutrophilic infiltrates, stromal necrosis, and disorganization of the collagen lamellae. The strong correlation between the clinical and histopathologic features of contact lens-induced Acanthamoeba keratitis in the pig as well as the anatomical similarity of the pig eye with the human eye make the porcine model a valuable tool for investigations of the immunology, cell biology, and therapy for Acanthamoeba keratitis.

Susceptibility of corneas from various animal species to in vitro binding and invasion by Acanthamoeba castellanii [corrected]

A crucial requirement for establishing corneal infection by the extracellular protozoal parasite, Acanthamoeba, is the ability of the parasite to bind to the corneal surface. In a series of in vitro studies, we examined the ability of Acanthamoeba castellanii [corrected] to adhere, invade, and damage normal, intact corneas of 11 mammalian and one avian species. A. castellanii [corrected] (80-90% trophozoites and 10-20% cysts) were incubated with corneas for 24 hours in vitro and examined by scanning electron microscopy (SEM). Results of several independent SEM experiments revealed that parasites not only failed to produce cytopathic effects but did not even bind to the corneal epithelium of mice, rats, cotton rats, horses, guinea pigs, cows, chickens, dogs, and rabbits. However, parasites adhered, invaded, and produced severe damage to human, pig, and Chinese hamster corneas during the 24-hour in vitro incubation period. Additional in vitro experiments quantified the binding of A. castellanii [corrected] to the corneas of selected susceptible and nonsusceptible species. In vitro binding assays revealed scant binding of parasites to mouse, rat, and rabbit (range = 5-20 parasites/7.07 mm2 corneal button). In contrast, extensive binding was observed on Chinese hamster, pig, and human corneas (range = 100-200 parasites/7.07 mm2 button). The results indicate that A. castellanii [corrected] exercises rigid host specificity at the host cell surface.

The differential effects of donor versus host Langerhans cells in the rejection of MHC-matched corneal allografts

The fate of MHC-identical, multiple minor H-disparate corneal grafts was examined in the rat. Although skin grafts exchanged between LEW and F344 rats were invariably rejected, only 26% of the corresponding corneal grafts underwent rejection. The immunologic privilege of the minor H-disparate corneal grafts was due, at least in part, to the absence of donor-derived Langerhans cells. Corneal grafts were normally devoid of donor-derived Langerhans cells; however, grafts pretreated with latex beads became infiltrated with donor-derived Langerhans cells and were rejected by 59% of the naive minor H--compatible recipients. By contrast, untreated LEW corneal grafts underwent rejection in 26% of the naive F344 hosts even though the grafts became heavily infiltrated with host-derived Langerhans cells. The immunologic privilege of minor H-disparate corneal grafts was not the result of efferent blockade or suppression of the immune response. F344 hosts bearing long-term surviving LEW corneal allografts were challenged with LEW skin grafts. In all cases, orthotopic skin grafts were rejected acutely. Moreover, all previously clear corneal grafts underwent rejection following skin graft rejection. Thus, the unique absence of donor-derived Ia+ passenger cells and the avascular graft bed conspire to provide the primary minor H-disparate corneal graft with an immunologic privilege not shared by other organ grafts.

In vitro transfer of rabbit corneal epithelium from carriers to denuded corneas or cryolathed lenticules

Rabbit corneal basal epithelial cells seeded onto fixed gelatin membranes or commercial collagen shields formed 3 to 5 cell layers after 1 to 3 weeks of culture at 35 degrees C in nutrient medium. The cells grew better, by comparison, in the collagen shields and eventually formed a multilayered tissue that resembled the stratified morphology of native epithelium. Transfer of multilayered cultures (prior to stratification) from these carriers in vitro to denuded corneal buttons or cryolathed lenticules resulted in complete adhesion of the grafted tissue to the underlying recipient buttons after 24- to 48-h incubations. After mechanically removing the carriers, most of the epithelial cells remained attached to the stromal surface. Our experimental findings indicated that both kinds of carriers may be suitable for epithelial transplantation, although the collagen shield is probably superior because of its better biocompatibility and physical characteristics.

Promotion of murine orthotopic corneal allograft survival by systemic administration of anti-CD4 monoclonal antibody

A mouse model of orthotopic corneal allograft rejection was used to examine the efficacy of anti-CD4 and anti-CD8 monoclonal antibodies in preventing immunologic rejection of corneal allografts. Although it is believed by many that corneal graft rejection is mediated, at least in part, by CD8-positive cytotoxic T-lymphocytes, systemic administration of anti-CD8 antibody did not reduce the rejection rate of corneal allografts that differed from the host at the entire major histocompatibility complex. By contrast, systemic administration of anti-CD4 monoclonal antibody reduced the rejection rate from 83% (untreated controls) to 33%. Fluorocytometric analysis of residual lymphoid populations showed that neither monoclonal antibody eliminated the inappropriate subset of T-cells in antibody-treated animals. In vitro cell-mediated cytotoxicity assays showed that both antibodies eliminated allospecific cytotoxic T-lymphocyte populations; however, only anti-CD4 antibody promoted graft survival. Thus, these results indicate that anti-CD4 monoclonal antibody is a powerful immunosuppressive agent for promoting corneal graft survival and that CD8-positive T-cells alone do not cause rejection of corneal allografts.

Class I disparate corneal grafts enjoy afferent but not efferent blockade of the immune response

Class I antigens are normally expressed on cells in all three layers of the cornea. In congenic rats that differ only at the single Class I locus RT1 A, central orthotopic corneal grafts were rejected 18% of the time with a mean survival time (MST) of 11.5 days. Pre-immunized recipients always rejected Class I disparate corneal grafts (100%, MST = 13.3 days). Surprisingly, the presence of donor Langerhans cells in the cornea at the time of grafting did not increase the rejection of grafts (20%, MST = 14.0 days). To determine if long term surviving grafts enjoyed immune priviledged in the form of efferent blockade, the recipients were challenged with skin grafts 4 to 6 weeks following corneal transplantation. All of the corneal grafts underwent rejection (100%, MST = 14.7 days). A number of important conclusions may be drawn from these studies. A single Class I mismatch is a weak barrier to successful engraftment of corneal grafts. However if the recipient has previously been exposed to donor antigens, a single Class I disparity is sufficient to provoke rejection of all subsequent corneal grafts. The susceptibility of long term surviving grafts to rejection induced by skin grafts indicates the orthotopic corneal grafts are antigenic but not immunogenic.

Growing human corneal epithelium on collagen shield and subsequent transfer to denuded cornea in vitro

Three fundamental in vitro experiments have been done in the present report: 1) comparison of three different nutrient media on their abilities to culture and passage the human corneal epithelial cells; 2) evaluation of the ability of extracellular matrix material to promote the growth of cultured human corneal epithelium on collagen corneal shields; and 3) determination of the feasibility of the shield to serve as a carrier for the transfer of cultured cells to allogeneic, denuded corneal surface in vitro. Primary cultures of human corneal epithelium were established from explants which were obtained from limbal and peripheral corneal tissue by three different nutrient media respectively: KGM (Keratinocyte Growth Medium), SHEM (Supplemental Hormonal Epithelial Medium), and one combination of the two media (KGM/SHEM). We found the KGM/SHEM combination to be more favorable because morphology was better preserved, the proliferation rate increased five-fold over the 14 days observed time course, and we were able to subculture the tissue for at least three passages. With this combined medium, a suspension of cultured corneal epithelial cells (5 x 10(5)/ml) was seeded onto either the concave surface of collagen corneal shields or onto shields which had been coated with extracellular matrix materials (Matrigel or type IV collagen). The cells attached readily to all the coated shields (20/20) but to only a few of the uncoated shields (3/10), and formed a stratified tissue (2 to 3 layers) within seven days once the cells attached. However, the cells on the shields coated with Matrigel failed to become confluent under these conditions. The stratified tissue on type IV collagen coated shields could then be subsequently transferred to denuded human corneal stroma in organ culture by placing them together and incubating for 2-7 days. After that, histologic examinations showed that the epithelial cells had attached tightly to the recipient stromal surface, even after the removal of the collagen shield.

Acceptance of H-Y-disparate corneal grafts despite concomitant immunization of the recipient

Male-specific, H-Y antigen is a widely utilized antigen system for analyzing the role of non-MHC transplantation antigens in graft rejection. In this study, we examined the role of H-Y antigen in corneal graft rejection. Orthotopic corneal grafts from male LBNF1 rats were transplanted to syngeneic female LBNF1 recipients. The male corneal grafts survived beyond 100 days on naive female recipients. In other experiments, hosts bearing clear male corneal grafts and systemically immunized with subcutaneous inoculations of male splenocytes followed by full-thickness male skin grafts failed to reject their corneal grafts, even though the male skin grafts were swiftly rejected. The inability of female hosts to reject existing male corneal grafts suggested that the cornea failed to express H-Y transplantation antigen. Further experiments, however, revealed that male-specific antigen was expressed on corneal grafts. Hosts bearing clear male grafts in the left eye rejected subsequent male skin grafts and promptly rejected male corneal grafts transplanted to the contralateral eye. Interestingly, the original male corneal grafts remained clear during the rejection of both the skin graft and the second corneal graft. The results indicate that corneal grafts representing minor histocompatibility disparities enjoy immunologic privilege in the naive host, even if the host is subsequently immunized systemically.

Post-transcriptional and transcriptional control of collagen gene expression in normal and modulated rabbit corneal endothelial cells

In a previous report, collagen synthesis did not correlate with steady-state collagen RNA levels; substantial amounts of type I collagen RNAs in endothelial cells were not translated into the respective protein. The current investigation was extended to study the level of the control mechanism in collagen gene expression in normal corneal endothelial cells or those modulated by corneal endothelium modulation factor released by polymorphonuclear leukocytes. Northern-blot analysis using cloned rabbit types I and IV cDNA probes (same species as RNA sources) demonstrated specific mRNA transcripts for collagen types I and IV in the endothelial cells, although the steady-state level of these mRNAs in modulated endothelial cells was low. The turnover rate of collagen RNAs was determined; normal cells contain very stable alpha 2(I) and alpha 2(IV) mRNAs whose half-lives exceed 24 hr. The same messages decayed rapidly in the modulated cells, where they had an apparent half-life of approximately 8 hr. Using nuclear run-off transcription, the rate of transcription in normal cells was found to be slightly lower than that in modulated cells. When the relative rate of collagen gene transcription was compared, that of alpha 2(I) was the lowest and of alpha 2(IV), the highest in both cells. The relative transcriptional rates of individual collagen chains did not account for the steady-state levels, suggesting that transcriptional regulation in corneal endothelial cells was less than was translational regulation. On the other hand, during early stages of corneal endothelial cell modulation induced by factors released by polymorphonuclear leukocytes there was a differential effect on both transcriptional rate and the steady-state level of collagen RNAs.(ABSTRACT TRUNCATED AT 250 WORDS)

In vivo and in vitro collagenolytic activity of Acanthamoeba castellanii

Axenic cultures of Acanthamoeba castellanii contained a collagenolytic enzyme that digested collagen shields and purified collagen in vitro. Specificity of biologic activity was determined by the addition of selected enzyme inhibitors to the assays and revealed that the parasite-conditioned medium contained both collagenase and lower concentrations of other proteolytic enzymes. However, most of the collagenolytic and pathogenic activity was directly attributable to specific collagenase. Intrastromal injection of sterile, Acanthamoeba-conditioned culture medium into naive Lewis rats produced corneal lesions clinically similar to and closely resembling those found in biopsy specimens of human patients diagnosed with acanthamoebic keratitis. Histopathologic analysis revealed moderate-to-severe neutrophil infiltration, disruption of stromal lamellae, and edema. Identical pathologic sequelae were produced by intrastromal injection of purified collagenase (25 units/ml). The pathogenicity of the soluble parasite-derived product was removed by passage over affinity columns armed with antibody specific for collagenase. These results indicated that soluble parasite-derived factors were capable of producing lesions characteristic of acanthamoebic keratitis and that the pathogenicity of these factors was either directly or indirectly attributable to specific collagenase activity.

Corneal endothelium modulation factor released by polymorphonuclear leukocytes. Partial purification and initial characterization

Polymorphonuclear leukocytes produce a polypeptide factor that is released into the medium. This factor is partially purified 83-fold by ammonium sulfate precipitation followed by chromatography on a DEAE-Sephadex or heparin-Sepharose column. The partially purified factor is trypsin-sensitive. This factor affects a population of rabbit corneal endothelial cells by modulating them to fibroblastlike cells and by further stimulating their growth, leading to the formation of colonies of multilayered modulated cells. There is a dose-dependent phenotypic modulation of corneal endothelial cells by the partially purified corneal endothelium modulation factor (CEMF); cell shape is changed and type I collagen synthesis is increased with greater concentrations of CEMF. Since the fully modulated endothelial cells have collagen phenotypes distinct from those of normal cells, collagen synthesized by the first-passaged cells (a mixture of normal and modulated cells) was determined by immunoblot analysis with antibodies specific against types I and IV collagens. The first-passaged cells, in the presence of CEMF, contained a large amount of type I collagen (modulated phenotype) and a dramatically reduced amount of type IV collagen (physiologic type), whereas the normal endothelial cells demonstrated strongly positive staining only with antibodies to type IV collagen. Using cloned cDNA probes, the relative quantities of the transcripts of these collagens were determined by slot-blot hybridization; the first-passaged cells contained type IV collagen RNA in an amount similar to the normal cells, but a slightly larger amount of type I mRNA. These results demonstrate a functional involvement of a protein factor released by polymorphonuclear leukocytes in modulating cell shape and collagen gene expression in corneal endothelial cells.