[Single non-blood-related umbilical cord blood transplantation using a reduced-intensity conditioning regimen for the treatment of severe aplastic anemia]

Objective: To evaluated the clinical efficacy of a reduced-intensity preconditioning regimen for single non-blood-related umbilical cord blood transplantation (sUCBT) in the treatment of severe aplastic anemia (SAA) . Methods: The clinical data of 63 patients with SAA who underwent sUCBT from January 2021 to July 2023 at the Department of Hematology of the First Affiliated Hospital of USTC were retrospectively analyzed. Fifty-two patients received total body irradiation/total bone marrow irradiation (TMI) combined with fludarabine or a cyclophosphamide- conditioning regimen (non-rATG group) , while 11 patients received rabbit anti-human thymocyte immunoglobulin (rATG) combined with TMI, fludarabine, or the cyclophosphamide-conditioning regimen (rATG group) . All patients received cyclosporine A and mycophenolate mofetil for graft-versus-host disease (GVHD) prophylaxis. Complications post-transplantation and long-term survival were compared between the two groups. Results: The baseline parameters were balanced between the two groups (P>0.05) . In the rATG group, all patients achieved stem cell engraftment, and in the non-rATG group, five patients had primary graft failure. There was no significant difference in the cumulative incidence of neutrophil engraftment at 42 days after transplantation or platelet engraftment at 60 days between the two groups. The incidence of grade Ⅱ-Ⅳ acute GVHD in the rATG group was significantly lower than in the non-rATG group (10.0% vs. 46.2% , P=0.032) , and the differences in the cumulative incidences of grade Ⅲ/Ⅳ acute GVHD and 1-year chronic GVHD were not statistically significant (P=0.367 and P=0.053, respectively) . There were no significant differences in the incidences of pre-engraftment syndrome, bacterial bloodstream infections, cytomegalovirus viremia, or hemorrhagic cystitis between the two groups (P>0.05 for all) . The median follow-up time for surviving patients was 536 (61-993) days, and the 1-year transplantation related mortality (TRM) of all patients after transplantation was 13.0% (95% CI 6.7% -24.3% ) . Among the patients in the non-rATG and rATG groups, 15.5% (95% CI 8.1% -28.6% ) and 0% (P=0.189) , respectively, had mutations. The 1-year overall survival (OS) rate of all patients after transplantation was 87.0% (95% CI 75.7% -93.3% ) . The 1-year OS rates in the rATG group and non-rATG group after transplantation were 100% and 84.5% , respectively (95% CI 71.4% -91.9% ) (P=0.198) . Conclusion: The preliminary results of sUCBT with a low-dose irradiation-based reduced-intensity conditioning regimen with fludarabine/cyclophosphamide for the treatment of patients with SAA showed good efficacy. Early application of low-dose rATG can reduce the incidence of acute GVHD after transplantation without increasing the risk of implantation failure or infection.

[Clinical characteristics and survival analysis of 15 cases of HIV-negative plasmablastic lymphoma]

目的

分析HIV阴性的浆母细胞淋巴瘤（PBL）患者的临床病理特征及转归。

方法

回顾性分析海军军医大学附属长海医院2013年1月至2019年8月诊断及治疗的15例HIV阴性PBL患者的临床病理资料及随访结果。

结果

15例HIV阴性PBL患者中男8例，女7例，中位年龄59（17~69）岁，均无明确的免疫抑制状态。所有患者均出现结外受累，Ann Arbor-Cotswolds分期Ⅰ、Ⅱ、Ⅲ、Ⅳ期分别为1例（6.7%）、2例（13.3%）、3例（20.0%）、9例（60.0%）。病理形态表现为类似免疫母细胞的大肿瘤细胞弥漫性增生，免疫组化示肿瘤细胞主要表达浆细胞标志CD38、CD138、Mum-1，B细胞标志CD20、CD10、PAX-5、BCL-6少见，Ki-67中位数为80%（70%~90%）。3例患者行EBER原位杂交检测，1例阳性。15例患者均接受化疗，80%（12/15）联合硼替佐米作为一线治疗。最佳疗效6例完全缓解（其中2例分别于治疗后4.9和26.1个月疾病进展），2例部分缓解（分别于治疗后3.0和6.8个月疾病进展），4例疾病进展，3例无法评估。中位随访时间30.3（4.8~61.1）个月，11例患者中位无进展生存（PFS）期6.8（95%CI 2.5~11.1）个月，预计3年PFS率为21.2%（95%CI 1.4%~56.8%）。所有患者中位总生存（OS）期为17.9（95%CI 5.6~30.2）个月，预计3年OS率为38.5%（95%CI 12.0%~65.0%）。

结论

HIV阴性PBL侵袭性强，结外受累常见，多数患者诊断时分期较晚。通过以硼替佐米为基础的强化疗方案序贯自体造血干细胞移植可望获得长期生存。

[Prognostic value of donor chimerism at +90 days after allogeneic hematopoietic stem cell transplantation in young patients with intermediate-risk acute myeloid leukemia]

Objective: To investigate the relationship between donor chimerism and relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT) . Methods: The clinical data of 105 patients with acute myeloid leukemia (AML) who underwent allo-HSCT and recurrence-free survival>90 days from January 2010 to January 2019 were retrospectively analyzed. The bone marrow samples were collected at 15, 30, 60, 90, 180, 270, 360 days after transplantation. Donor chimerism was detected by single nucleotide polymorphism (SNP) -PCR. Results: Of the 105 patients, 43 cases were male and 62 cases were female, with a median age of 38 (16-60) years. Till April 2019, the median follow-up was 843 (94-3 261) days. Ninety days after transplantation, 18 cases relapsed, 33 cases died, and 72 cases survived. The 3-year overall survival (OS) rate was (66.8±5.1) %, and the recurrence-free survival (RFS) rate was (65.1±5.0) %. Pre-transplant disease status, pre-transplant minimal residual disease (MRD) , and 90 day post-transplantation chimerism were independent risk factors related to RFS. The risk of recurrence was significantly increased in patients with a donor chimerism rate ≤97.24% at 90 days after transplantation[HR=6.921 (95%CI 2.669-17.950) , P<0.001], which was considered as a sign of early relapse. Conclusion: SNP-PCR is an applicable method for detecting donor chimerism in patients after allo-HSCT. Chimerism rate equal or less than 97.24% at 90 days after transplantation predicts a higher risk of relapse.

[Efficacy of Hyper-CVAD/MA and CHALL-01 regimens in the treatment of Philadelphia chromosome-positive adult acute lymphoblastic leukemia patients under 60 years old]

Objective: To compare the difference of efficacy between traditional Hyper-CVAD/MA regimen and the adolescents inspired chemotherapy regimen, CH ALL-01, in treatment of adult Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph(+) ALL) . Methods: In this study we retrospectively analyzed 158 Ph(+) ALL patients receiving Hyper-CVAD/MA regimen (n=63) or CHALL-01 regimen (n=95) in our center and Changzheng hospital from January 2007 to December 2017, excluding patients with chronic myeloid leukemia in blast crisis. Tyrosine kinase inhibitor (TKI) was administered during induction and consolidation chemotherapy. Patients who underwent hematopoietic stem cell transplantation received TKI as maintenance therapy. Results: Of them, 91.1% (144/158) patients achieved complete remission (CR) after 1-2 courses of induction. CR rate was 90.5% (57/63) for patients in Hyper-CVAD/MA group and 91.6% (87/95) for patients in CHALL-01 group. There was no difference in CR rates between the two groups (χ(2)=0.057, P=0.811) . The last follow-up was June 2018. A cohort of 134 CR patients could be used for further analysis, among them, 53 patients received Hyper-CVAD/MA regimen and other 81 patients received CHALL-01 regimen. The molecular remission rates were significantly higher in CHALL-01 group (complete molecular response: 44.4%vs 22.6%; major molecular response: 9.9% vs 18.9%) (χ(2)=7.216, P=0.027) . For the patients in Hyper-CVAD/MA group, the 4-year overall survival (OS) was 44.81% (95%CI: 30.80%-57.86%) and the 4-year disease free survival (DFS) was 37.95% (95%CI: 24.87%-50.93%) . For patients received CHALL-01 regimen, the 4-year OS was 55.63% (95%CI: 39.07%-69.36%) (P=0.037) and 4 year DFS was 49.06% (95%CI: 34.24%-62.29%) (P=0.015) , while there was no significant difference in 4 year cumulative incidence of relapse (CIR) (P=0.328) or cumulative incidence of nonrelapse mortality (CI-NRM) (P=0.138) . The rate of pulmonary infection was lower in patients received CHALL-01 regimen compared with patients received Hyper-CVAD regimen (43.4% vs 67.9%, χ(2)=7.908, P=0.005) . Conclusions: Outcome with CHALL-01 regimen appeared better than that with the Hyper-CVAD/MA regimen in Ph(+) ALL, which has lower incidence of pulmonary infection, higher molecular remission rate and better OS and DFS.

Corneal Toxicity Associated With Aquarium Coral Palytoxin

PURPOSE

To report a series of patients who developed corneal toxicity after exposure to aquarium coral palytoxin.

DESIGN

Multicenter retrospective case series.

METHODS

Retrospective review.

RESULTS

Seven patients presented with corneal findings ranging from superficial punctate epitheliopathy to bilateral corneal melt with subsequent perforation. Among those with mild corneal findings, resolution was achieved with topical steroids and lubrication, whereas some patients who developed progressive corneal melt required therapeutic penetrating keratoplasty. The history in all patients revealed exposure to aquarium zoanthid corals shortly before disease onset. A review of the literature revealed that there are few prior reports of coral-associated corneal toxicity and that some species of coral secrete a substance known as palytoxin, a potent vasoconstrictor that inhibits the membranous sodium-potassium ATPase pump across cell types and can cause rapid death if inhaled or ingested.

CONCLUSIONS

This is the largest case series to date demonstrating patients with aquarium coral palytoxin-associated corneal toxicity, and is the first to provide details of related histopathologic findings. Similar to other forms of toxic keratoconjunctivitis, a detailed history and careful clinical assessment are required, as well as timely removal of the offending agent from the patients' ocular milieu and environment. Mild ocular surface and corneal disease may be treated effectively with aggressive topical steroid therapy and lubrication. Given the potential severity of ocular as well as systemic adverse effects, there should be increased awareness of this entity among eye care professionals, aquarium enthusiasts, and the general public.

Mitochondrial oxygen metabolism in primary human lens epithelial cells: Association with age, diabetes and glaucoma

PURPOSE

The hypoxic environment around the lens is important for maintaining lens transparency. Lens epithelial cells (LECs) play a key role in lens metabolism. We measured oxygen consumption to assess the role of human LECs in maintaining hypoxia around the lens, as well as the impact of systemic and ocular diagnosis on these cells.

METHODS

Baseline cellular respiration was measured in rabbit LECs (NN1003A), canine kidney epithelial cells (MDCK), trabecular meshwork cells (TM-5), and bovine corneal endothelial cells (CCEE) using a XF96 Extracellular Flux Analyzer (Seahorse Bioscience, North Billerica, MA), which measures oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) in vitro. Following informed written consent, lens capsule epithelial cells were obtained from patients during cataract surgery and were divided into small explants in 96-well plates. Capsules were removed when LECs became confluent. OCR was normalized to the number of cells per well using rabbit LECs as a standard. The effect of patient age, sex, race, and presence of diabetes or glaucoma on oxygen consumption was assessed by using the Mann-Whitney U test and multivariate regression analysis.

RESULTS

Primary LECs were obtained from 69 patients. The OCR from donors aged 70 and over was lower than that of those under 70 years (2.21±1.037 vs. 2.86±1.383 fmol/min/cell; p<0.05). Diabetic patients had lower OCR than non-diabetic patients (2.02±0.911 vs. 2.79±1.332fmol/min/cell; p<0.05), and glaucoma patients had lower OCR than non-glaucoma patients (2.27±1.19 vs. 2.83±1.286 fmol/min/cell; p<0.05). Multivariate regression analysis confirmed that donors aged 70 and over (p<0.05), diabetic patients (p<0.01), and glaucoma patients (p<0.05) had significantly lower OCR, independent of other variables. Gender and race had no significant effect on OCR.

CONCLUSIONS

The lower oxygen consumption rate of human LECs in older donors and patients with diabetes or glaucoma could contribute to cataract development. Diabetes and glaucoma are particularly important factors associated with decreased OCR, independent of age. Ongoing studies are examining pO2 at the anterior surface of the lens in vivo and oxygen consumption in the patient's LECs.

Novel CHST6 gene mutations in 2 unrelated cases of macular corneal dystrophy

PURPOSE

To investigate the possible mutations in the carbohydrate sulfotransferase 6 (CHST6) gene of 2 unrelated cases of macular corneal dystrophy (MCD) and to report atypical stromal deposits in one of them.

METHODS

Corneal tissues were stained with antisulfated keratan sulfate (KS), antitransforming growth factor beta 1-induced protein (TGFBIp), thioflavin-T, alcian blue, and Masson trichrome. Sequencing was performed to identify potential mutations in the CHST6 gene and the fourth and twelfth exons of the TGFBI gene.

RESULTS

Alcian blue staining revealed the presence of multiple subepithelial and intrastromal mucopolysaccharide deposits, confirming the diagnosis of MCD in both cases. Immunofluorescence staining in case 1 revealed the presence of sulfated KS only in the keratocytes and select endothelial cells, consistent with MCD type IA. Preferential expression of sulfated KS was observed in keratocytes and extracellular stromal matrix in case 2, consistent with MCD type II. Atypical subepithelial and superficial stromal deposits were observed in case 1, which stained positively with alcian blue, eosin, Masson trichrome, and thioflavin-T indicating the presence of hyaline and amyloid materials. CHST6 gene sequencing revealed 2 heterozygous mutations in case 1 (a p.Arg211Gln and a novel mutation of p.Arg177Gly) and a novel homozygous mutation of p.Pro186Arg in case 2. No mutations were found in exons 4 or 12 of the TGFBI gene in case 1.

CONCLUSIONS

Secondary hyalinosis and amyloidosis occur in a case of MCD type IA with a novel p.Arg177Gly mutation in CHST6. A novel p.Pro186Arg mutation in CHST6 is associated with MCD type II in an African American.

Denaturation and solvent effect on the conformation and fibril formation of TGFBIp

PURPOSE

Transforming growth factor beta-induced protein (TGFBIp) aggregates into the phenotypic amyloid fibrils and/or non-amyloid deposits in corneal dystrophies and other disorders. While significant progress has been made in molecular genetics to successfully establish the link between the missense mutations of TGFBI and TGFBIp-related corneal dystrophies, the underlying mechanism for the abnormal aggregation remains elusive due to the lack of insights into the conformational perturbations induced by mutations. In the present study, we examined the effects of denaturants and a co-solvent on recombinant TGFBIp, with a focus on protein conformational changes and amyloid fibril formation.

METHODS

Recombinant TGFBIp was subjected to various spectroscopic studies, such as far-ultraviolet circular dichroism (far-UV CD), intrinsic tryptophan fluorescence and quenching, and 1-anilinonaphthalene-8-sulfonic acid (ANS) fluorescence, under various denaturing conditions (urea and guanidine hydrochloride [GndHCl], acidic pH, and trifluoroethanol [TFE, co-solvent]). A thioflavin T (ThT) fluorescence assay was used to determine the fibril formation of TGFBIp. In addition, a rabbit polyclonal antibody against the oligomer precursors that initiate the formation of amyloid fibrils was also used in dot blot experiments to detect the formation of prefibrillar precursors.

RESULTS

The purified recombinant TGFBIp is in the folded state according to its intrinsic tryptophan fluorescence analyses. A single-step unfolding process was observed in the GndHCl denaturation experiment. Results from far-UV CD, intrinsic tryptophan fluorescence, and ANS fluorescence experiments showed that TFE exerted its solvent effects by initially unfolding and transforming TGFBIp to a beta-sheet-enriched conformer at 20%. When increased to 40%, TFE changed TGFBIp into a non-native alpha-helix conformer. Although GndHCl and TFE led to protein unfolding, enhanced fibril formation could only be observed in the presence of TFE and at acidic pH, according to the ThT fluorescence assays. The paradigmatic protofibrillar TGFBIp oligomers were also detected during the fibril formation by the dot blot experiment.

CONCLUSIONS

Our results suggest that protein unfolding may serve as the prerequisite but is not sufficient for the fibrillogenesis. Other factors, such as the solvent used, fragmentation, or pH, may also be crucial for the formation of TGFBIp fibrils.

Urinary incontinence and pelvic floor dysfunction in Asian-American women

OBJECTIVE

The objective of the study was to describe the prevalence, risk factors, and impact of urinary incontinence and other pelvic floor disorders among Asian-American women.

STUDY DESIGN

This was a population-based cohort study of older women randomly selected from age and race strata.

RESULTS

Weekly urinary incontinence was reported by 65 of 345 Asian women (18%), with stress and urge incontinence being approximately equally common. In multivariate analysis, higher body mass index (greater than 25 kg/m2) was associated with both stress incontinence (odds ratio 4.90, 95% confidence interval 1.76 to 13.68) and urge incontinence (odds ratio 2.49, 95% confidence interval 1.01 to 6.16) in Asians. Hysterectomy was a significant risk factor for stress incontinence (odds ratio 2.79, 95% confidence interval 1.03 to 7.54). Only 34% of Asian women with weekly urinary incontinence reported ever having sought treatment. Pelvic floor exercises were the most common form of treatment, being used by 29% of Asian women with weekly incontinence. Asians were less likely then white women to report anal incontinence (21% versus 29%, P = .007), although this difference became nonsignificant after adjusting for differences in risk factors.

CONCLUSION

Asian women share some risk factors for stress and urge urinary incontinence with white women. Urinary incontinence is associated with anal incontinence among Asian women.

Single breath-holdT1 measurement using low flip angle TrueFISP

A method for estimating T1 using a single breath-hold, segmented, inversion recovery prepared, true fast imaging with steady-state precession (sIR-TrueFISP) acquisition at low flip angle (FA) was implemented in this study. T1 values measured by sIR-TrueFISP technique in a Gd-DTPA-doped water phantom and the human brain and abdomen of healthy volunteers were compared with the results of the standard IR fast spin echo (FSE) technique. A good correlation between the two methods was observed (R2=0.999 in the phantom, and R2=0.943 in the brain and abdominal tissues). The T1 values of the tissues agreed well with published results. sIR-TrueFISP enables fast measurements of T1 to be obtained within a single breath-hold with good accuracy, which is particularly important for chest and abdominal imaging.

Mycobacterium interface keratitis after laser in situ keratomileusis

PURPOSE

To report the clinical course, management, and outcome of infectious interface keratitis caused by mycobacterium species after laser in situ keratomileusis (LASIK).

DESIGN

A small noncomparative interventional case series.

PARTICIPANTS

Five eyes in four patients who underwent LASIK in different locations around the world and had culture-positive mycobacterium keratitis develop.

INTERVENTION

The LASIK flap was lifted or amputated, samples were submitted for Ziehl-Neelsen acid-fast stain and Lowenstein-Jensen's agar cultures for diagnosis; topical treatment with fortified clarithromycin and amikacin was administered until clinical resolution.

MAIN OUTCOME MEASURES

Time periods from onset to diagnosis and from diagnosis to clinical resolution, and the final visual acuity.

RESULTS

Onset of symptoms of infection occurred after a mean of 20 days (range, 11 days-6 weeks) after LASIK or an enhancement procedure. Definitive diagnosis was obtained after a mean period of 4.5 weeks (range, 12 days-8 weeks) from onset. Keratitis resolved within 8.4 weeks (range, 1-18 weeks) of treatment with fortified clarithromycin and amikacin. Corticosteroids were found to worsen and prolong the course of disease. In four of five eyes the LASIK flap was amputated.

CONCLUSIONS

Mycobacterial keratitis is a potentially vision-threatening complication after LASIK, characterized by a long latent period, delayed diagnosis, and a protracted course even under intensive specific antibiotic therapy. Inclusion of specific culture media and staining protocols for mycobacteria, along with aggressive treatment on diagnosis, including lifting or amputating the LASIK flap, culturing, topical fortified clarithromycin and amikacin, while avoiding corticosteroids, may significantly improve resolution of the infection and potentially improve the visual outcome.

Analgesic domains of interferon-alpha

Interferon-alpha (IFNalpha) is not only an immunoregulatory factor, but is also an analgesic molecule. We ever reported that there exist distinct domains in IFNalpha molecule that mediate immune and analgesic effects respectively and inferred that the analgesic domain locates around the 122nd Tyr residue of IFNalpha molecule in the tertiary structure. After the 36th Phe residue, which was located closely to the 122nd Tyr residue in the tertiary structure, was mutated to Ser using site-directed mutagenesis, the analgesic activity of this mutant lost completely, but the antiviral activity of IFNalpha still maintained 40.5% of wild type IFNalpha. The results suggest that the 36th Phe residue is one of the constituent for the analgesic domain of IFNalpha and inferred that the analgesic domain of IFNalpha consists of the 122nd Tyr and the residues around the 122nd in the tertiary structure, which include the 36th Phe.

[Effects of GDNF on primary culture of spinal cord neurons]

The effect of GDNF on long-term cultured spinal cord neurons was studied. GDNF could promote spinal cord neurons survival after 7 d or 14 d culture by MTT assay. The effect of GDNF on growth cones, neuron soma magnitude, neurite length and spines formulation of spinal cord neurons in cell culture was observed by phase microscopy, Nissl stain and NSE immunocytochemistry stain. The results indicated that GDNF had significant trophic effects on long-term cultured spinal cord neurons.

[Expression of human GDNF in methyltrophic yeast Pichia pastoris and silkworm larvae]

The cDNA encoding glial cell derived neurotrophic factor (GDNF) was cloned into the Pichia expression vector pPIC9K and then transformed into his4 mutant yeast GS115 by electroporation. Multicopy transformants were screened by various G418 concentrations and induced by methanol. The human GDNF gene was cloned into the baculovirus transfer vector pBacPAK8. The recombinant transfer vector pBacPAK-GDNF was coinfected with linear Bm-BacPAK6 DNA into BmN cells. The recombinant virus was screened and plaque-purified. The silkworm larvae were infected with the recombinant virus and collected 5 days later. SDS-PAGE and Western blot confirmed that GDNF was expressed in Pichia culture medium and silkworm larvae hemolymph. The GDNF protein expressed in Pichia and silkworm larvae could significantly promote the survival and neurite outgrowth of dopaminergic neurons.

[Distinct structural bases of the immunoregulatory and central analgesic effects of IFNalpha]

Interferon-alpha (IFNalpha), a cytokine, is also an analgesic molecule. There is significant cross reactivity between IFNalpha and anti-opioid sera, suggesting a strong antigenic relatedness between human IFNalpha molecules and opioid peptides. Different structural basis of the immunoactivity and analgesic effect of IFNalpha can be demonstrated by different reactivities of the two reactions towards different mutants of IFNalpha obtained by using the site-directed mutagenesis. When the 129th Tyr residue of human IFNalpha was mutated to Ser, the immunoactivity of the mutant almost disappeared, while the strong analgesic activity still persisted, which could be blocked by naloxone. These results indicate that there exist distinct domains in the IFNalpha molecule, which mediate immune and analgesic effects differentially, and that the receptor mechanism underlying immune and analgesic effects of IFNalpha may be different.

[Purity analysis of cephalosporins with capillary zone electrophoresis]

A capillary zone electrophoresis method is proposed for the purity determination of nine cephalosporin drugs. A background electrolyte comprising of either 20 mmol/L pH 9.20 borate buffer or 20 mmol/L pH 6.86 phosphate buffer was used for most drugs studied except for cefaloridine which formed neutral molecules at these pH values. For it 50 mmol/L pH 2.05 phosphate buffer was used instead. Internal normalization method was employed for quantitation. The method is simple, rapid and versatile. Analysis was completed within 8 min. The merits and limitations of the method were also discussed.

Evaluation of corneal thickness and topography in normal eyes using the Orbscan corneal topography system

AIMS

To map the thickness, elevation (anterior and posterior corneal surface), and axial curvature of the cornea in normal eyes with the Orbscan corneal topography system.

METHODS

94 eyes of 51 normal subjects were investigated using the Orbscan corneal topography system. The anterior and posterior corneal elevation maps were classified into regular ridge, irregular ridge, incomplete ridge, island, and unclassified patterns, and the axial power maps were grouped into round, oval, symmetric bow tie, asymmetric bow tie, and irregular patterns. The pachymetry patterns were designated as round, oval, decentred round, and decentred oval.

RESULTS

The thinnest point on the cornea was located at an average of 0.90 (SD 0. 51) mm from visual axis and had an average thickness of 0.55 (0.03) mm. In 69.57% of eyes, this point was located in the inferotemporal quadrant, followed by the superotemporal quadrant in 23.91%, the inferonasal quadrant in 4.35%, and the superonasal quadrant in 2.17%. Among the nine regions of the cornea evaluated (central, superotemporal, temporal, inferotemporal, inferior, inferonasal, nasal, superonasal, and superior) the central cornea had the lowest average thickness (0.56 (0.03) mm) and the superior cornea had the greatest average thickness (0.64 (0.03) mm). The mean simulated keratometry (SimK) was 44.24 (1.61)/43.31 (1.66) dioptres (D) and the mean astigmatism was 0.90 (0.41) D. Island (71.74%) was the most common elevation pattern observed in the anterior corneal surface, followed by incomplete ridge (19.57%), regular ridge (4.34%), irregular ridge (2.17%), and unclassified (2.17%). Island (32.61%) was the most common topographic pattern in the posterior corneal surface, following by regular ridge (30.43%), incomplete ridge (23. 91%), and irregular ridge (13.04%) patterns. Symmetric bow tie was the most common axial power pattern in the anterior cornea (39.13%), followed by oval (26.07%), asymmetric bow tie (23.91%), round (6. 52%), and irregular (4.53%) patterns. In the pachymetry maps, 47.83% of eyes had an oval pattern, and round, decentred oval, and decentred round were observed in 41.30%, 8.70%, and 2.18% of eyes, respectively.

CONCLUSION

The information on regional corneal thickness, corneal elevation and axial corneal curvature obtained with the Orbscan corneal topography system from normal eyes provides a reference for comparison with diseased corneas. The Orbscan corneal topography system is a useful tool to evaluate both corneal topography and corneal thickness.

Expression and characterization of a DNase I-Fc fusion enzyme

Recombinant human deoxyribonuclease I (DNase I) is an important clinical agent that is inhaled into the airways where it degrades DNA to lower molecular weight fragments, thus reducing the viscoelasticity of sputum and improving the lung function of cystic fibrosis patients. To investigate DNases with potentially improved properties, we constructed a molecular fusion of human DNase I with the hinge and Fc region of human IgG1 heavy chain, creating a DNase I-Fc fusion protein. Infection of Sf9 insect cells with recombinant baculovirus resulted in the expression and secretion of the DNase I-Fc fusion protein. The fusion protein was purified from the culture medium using protein A affinity chromatography followed by desalting by gel filtration and was characterized by amino-terminal sequence, amino acid composition, and a variety of enzyme-linked immunosorbent assays (ELISA) and activity assays. The purified fusion contains DNase I, as determined by a DNase I ELISA and an actin-binding ELISA, and an intact antibody Fc region, which was quantified by an Fc ELISA, in a 2:1 stoichiometric ratio, respectively. The dimeric DNase I-Fc fusion was functionally active in enzymatic DNA digestion assays, albeit about 10-fold less than monomeric DNase I. Cleavage of the DNase I-Fc fusion by papain resulted in a specific activity comparable to the monomeric enzyme. Salt was inhibitory for wild type monomeric DNase I but actually enhanced the activity of the dimeric DNase I-Fc fusion. The DNase I-Fc fusion protein was also less Ca2+-dependent than DNase I itself. These results are consistent with a higher affinity of the dimeric fusion protein to DNA than monomeric DNase I. The engineered DNase I-Fc fusion protein described herein has properties that may have clinical benefits.

Nontuberculous mycobacterial keratitis in south Florida

OBJECTIVE

This study aimed to review the clinical features, therapeutic response, and histopathology of cases of nontuberculous mycobacterial keratitis at the Bascom Palmer Eye Institute.

DESIGN AND PARTICIPANTS

Retrospective review of medical records, clinical photographs, histopathology, and microbiology of 24 cases of nontuberculous acid-fast keratitis over the past 15 years.

RESULTS

Causal organisms included Mycobacterium chelonae (16), M. fortuitum (3), M. avium-intracellulare (2), M. nonchromogenicum (1), M. triviale (1), and M. asiaticum (1). Clinically, the keratitis had a superficial location except in those patients with a history of surgery. Amikacin was the most commonly used antibiotic (63%). Three patients were treated with Clarithromycin. In one patient, it was stopped because of toxicity; the other two had resolution of their infiltrates. Fifty-five percent did not respond to topical antimicrobial therapy. The organisms as a group were sensitive to amikacin and Clarithromycin and resistant to the fluoroquinolones. Sixty-four percent of the group that failed to respond to medical treatment were treated with steroids after the diagnosis was known, in comparison to 44% of the group treated successfully with medications. The histopathology of the patients treated with steroids showed minimal inflammation despite a large number of organisms, in contrast to the dense infiltrates seen in the specimens from patients not treated with topical steroids.

CONCLUSION

Nontuberculous mycobacterial keratitis is a chronic insidious infection that is often unresponsive to medical therapy. The authors recommend that steroids be withheld. Based on the authors' experience of three patients, topical Clarithromycin may hold promise as a therapeutic agent. Lamellar keratectomy or penetrating keratoplasty should be considered in those patients who do not respond to medical therapy or those who have recurrent exacerbations on attempted weaning of topical antibiotic therapy.

Glucocorticoids stimulate p21 gene expression by targeting multiple transcriptional elements within a steroid responsive region of the p21waf1/cip1 promoter in rat hepatoma cells

Glucocorticoids can induce a G1 arrest in the cell cycle progression of BDS1 rat hepatoma cells. In these cells, dexamethasone, a synthetic glucocorticoid, stimulated a rapid and selective increase in expression of the p21 cyclin-dependent kinase (CDK) inhibitor mRNA and protein and virtually abolished CDK2 phosphorylation of the retinoblastoma protein. Expression of the p27 CDK inhibitor, and other G1-acting cell cycle proteins, remained unaffected. Dexamethasone stimulated p21 promoter activity in a p53-independent manner that required functional glucocorticoid receptors. Transforming growth factor-beta, which also induced a G1 cell cycle arrest of the hepatoma cells, failed to elicit this response. Analysis of 5' deletions of the p21 promoter uncovered a glucocorticoid responsive region between nucleotides -1481 and -1184, which does not contain a canonical glucocorticoid response element but which can confer dexamethasone responsiveness to a heterologous promoter. Fine mapping of this region uncovered three distinct 50-60-base pair transcriptional elements that likely function as targets of glucocorticoid receptor signaling. Finally, ectopic expression of p21 had no effect on hepatoma cell growth in the absence of glucocorticoids but facilitated the ability of dexamethasone to inhibit cell proliferation. Thus, our results have established a direct transcriptional link between glucocorticoid receptor signaling and the regulated promoter activity of a CDK inhibitor gene that is involved in the cell cycle arrest of hepatoma cells.

Stimulated neutrophils induce myosin light chain phosphorylation and isometric tension in endothelial cells

The mechanism or mechanisms by which polymorphonuclear leukocytes (PMN) penetrate junctions between neighboring endothelial cells (EC) to traverse endothelial barriers remain unresolved. We report that chemoattractant-stimulated PMN induce a coordinate increase in both phosphorylation of serine 19 and threonine 18 of EC myosin regulatory light chains and isometric tension generation by EC monolayers. Unstimulated PMN had no effect on either parameter. These findings, coupled with our previous report (Huang et al., J. Cell Biol. 120: 1371-1380, 1993) that chemoattractant-stimulated PMN cause a rise in EC cytosolic free Ca2+, provide strong presumptive evidence that myosin light chain kinase is the EC enzyme responsible for initiating myosin light chain phosphorylation, EC contraction, and isometric tension generation in response to chemoattractant-stimulated PMN. We suggest that, by inducing phosphorylation of EC cytoskeletal proteins, chemoattractant-stimulated PMN induce EC to open their intercellular junctions, thereby facilitating transendothelial movement of these leukocytes.

Repression of glucocorticoid receptor transactivation and DNA binding of a glucocorticoid response element within the serum/glucocorticoid-inducible protein kinase (sgk) gene promoter by the p53 tumor suppressor protein

sgk is a novel member of the serine/threonine protein kinase family that is transcriptionally regulated by serum and glucocorticoids in Rat2 fibroblasts and in mammary epithelial cells. 5'-Deletion analysis of the sgk promoter, using a series of sgk-CAT. (chloramphenicol acetyltransferase) chimeric reporter gene plasmids, defined a glucocorticoid-responsive region that contains a glucocorticoid response element (sgkGRE) between -1000 and -975 bp. The sgkGRE is specifically bound by glucocorticoid receptors and is sufficient to confer glucocorticoid responsiveness to a heterologous promoter in several cell lines. Strikingly, cotransfection of either the murine or human wild type p53, but not a mutant p53, repressed the dexamethasone-stimulated transactivation of reporter plasmids containing either the sgkGRE or a consensus GRE. Gel shift analysis revealed that in vitro synthesized p53 prevented binding of the glucocorticoid receptor both to the sgkGRE as well as to a consensus GRE. The p53-mediated repression of dexamethasone-induced sgkGRE activity required both the DNA binding and transactivation functions of the p53 protein. Activation of endogenous p53, by exposure to UV light, repressed the glucocorticoid receptor transactivation of a consensus GRE-CAT reporter plasmid in transfected cells. Conversely, activated glucocorticoid receptors suppressed the transactivation function of p53, while transrepression by p53 was largely unaffected. The presented data demonstrate that sgk is a primary glucocorticoid-responsive protein kinase gene that implicates a new pathway of cross-talk between steroid receptor signaling and cellular phosphorylation cascades. In addition, our study provides the first evidence of mutual interference of transactivation functions of p53 and the glucocorticoid receptor, possibly through their direct interaction.

p53 stimulates promoter activity of the sgk. serum/glucocorticoid-inducible serine/threonine protein kinase gene in rodent mammary epithelial cells

sgk is a novel member of the serine/threonine protein kinase gene family that is transcriptionally regulated by serum and glucocorticoids in mammary epithelial cells. To functionally determine if the sgk promoter is regulated by the p53 tumor suppressor protein in mammary cells, a series of sgk promoter fragments with 5'-deletions were linked to the bacterial chloramphenicol acetyltransferase gene (sgk-CAT) and transiently co-transfected into nontumorigenic NMuMG or transformed Con8Hd6 mammary epithelial cells with p53 expression plasmids. Wild-type p53, but not mutant p53, strongly stimulated sgk promoter activity in both mammary epithelial cell lines. These effects were mediated by specific regions within the sgk promoter containing p53 DNA-binding sites. The sgk p53 sequence at-1380 to-1345 (site IV) was sufficient to confer p53-dependent transactivation to a heterologous promoter, and p53 was capable of binding to this sequence in vitro as assessed by gel shift analysis. In the nontumorigenic NMuMG epithelial cell line, cotransfection of wild-type p53 strongly stimulated the activities of both the sgk promoter and the well characterized p53-responsive p21/Waf1 promoter, whereas in Rat-2 fibroblasts, wild-type p53 repressed the basal activities of both promoters, revealing that sgk and p21/Waf1 are similarly regulated in a cell type-specific manner. Taken together, these results demonstrate that sgk is a new transcriptional target of p53 in mammary epithelial cells and represent the first example of a hormone-regulated protein kinase gene with a functionally defined p53 promoter recognition element.

[Role of locus coeruleus in analgesia caused by stimulation of supraoptic nucleus]

The effects of stimulation of supraoptic nucleus (SON) on the changes of oxytocin (OT), arginine vasopressin (AVP), norepinephrine (NE) and serotonin (5-HT) in the perfusate of locus coeruleus (LC) and changes of pain threshild (PT) were studied by methods of microinjection, radioimmunoassay (RIA) and high pressure liquid chromatography (HPLC) technique. The results showed that the OT contents at 30, 60 and 90 min after stimulation, that of AVP at 30 min and 5-HT at 60 min were increased significantly, while the NE contents at 30 and 60 min were decreased markedly. Injection of V1 antagonist into LC did not affect the analgesic effect caused by administration of L-glutamic acid (L-Glu) into SON, which, however, could be partially inhibited by V2 antagonist or even reversed by OT antagonist. The above results suggested that the analgesic effect due to stimulation of SON is caused by increase of 5-HT and decreases of NE in the LC though the action of OT released by SON on OT and V2 receptor in LC.

Aspergillus niger as an unusual cause of scleritis and endophthalmitis

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Efficacy of lodoxamide 0.1% ophthalmic solution in resolving corneal epitheliopathy associated with vernal keratoconjunctivitis

A multicenter, randomized, double-masked, parallel-group study compared the long-term efficacy and safety of lodoxamide 0.1% ophthalmic solution and placebo in 118 patients with vernal keratoconjunctivitis. The test drugs were instilled four times daily for 90 days. Lodoxamide 0.1% ophthalmic solution was significantly (P < .05) more effective than placebo in lowering severity scores for epithelial disease and corneal staining, evidence of the superior efficacy of lodoxamide 0.1% ophthalmic solution in reversing the corneal complications commonly associated with moderate to severe vernal keratoconjunctivitis. Additionally, lodoxamide 0.1% ophthalmic solution ameliorated the other key signs of vernal keratoconjunctivitis, including upper tarsal papillae, limbal signs (papillae, hyperemia, and Trantas' dots), and conjunctival discharge. The between-group differences in the relief of symptoms (itching, tearing, and photophobia) were clinically significant but not always statistically significant. Treatment-related adverse events were reported with similar frequency in both treatment groups, and none were serious.

Association of herpes zoster ophthalmicus with acquired immunodeficiency syndrome and acute retinal necrosis

We conducted a review to investigate the prevalence of human immunodeficiency virus (HIV), or acquired immunodeficiency syndrome (AIDS), in patients with herpes zoster ophthalmicus, as well as the incidence of acute retinal necrosis after herpes zoster ophthalmicus. All charts of patients seen at our institution between 1987 and 1992 with a primary diagnosis of herpes zoster ophthalmicus were reviewed. Of 112 patients with herpes zoster ophthalmicus, 29 (26%) had HIV or AIDS. All these patients were younger than 50 years at the time of diagnosis. Five of 29 (17%) immunocompromised patients had acute retinal necrosis after herpes zoster ophthalmicus. No acute retinal necrosis was identified in the nonimmunocompromised patients after herpes zoster ophthalmicus. We recommend that all patients younger than 50 years who have herpes zoster ophthalmicus at initial examination be tested for HIV. Additionally, HIV-infected patients should be monitored closely after herpes zoster ophthalmicus for development of acute retinal necrosis. Long-term oral prophylactic as well as initial high-dose intravenous acyclovir may be appropriate in HIV-infected individuals with herpes zoster.

Effective treatment of phlyctenular keratoconjunctivitis with oral tetracycline

PURPOSE

To determine the clinical characteristics, possible etiologic agents, and response to oral antibiotic therapy in patients with phlyctenular keratoconjunctivitis.

METHODS

The authors reviewed the medical records of the 17 patients with phlyctenular keratoconjunctivitis who were seen and treated at the Bascom Palmer Eye Institute between 1981 and 1991.

RESULTS

All 17 patients were younger than 18 years of age at the onset of their disease. Girls (n = 14) outnumbered boys (n = 3) 4:1. Significant incapacitating symptoms and ocular morbidity occurred frequently, including three perforated corneas. Five of ten patients who were tested for Chlamydia infection had positive test results and five patients possibly had early rosacea dermatitis. All patients experienced long-term remission of their ocular disease after a course of oral tetracycline or erythromycin. Two patients demonstrated unique linear (fascicular) corneal phlyctenules.

CONCLUSION

Oral tetracycline or erythromycin treatment produces long-lasting remission of phlyctenular keratoconjunctivitis in affected children.

Endothelial cell cytosolic free calcium regulates neutrophil migration across monolayers of endothelial cells

Polymorphonuclear leukocytes (PMN) traverse an endothelial cell (EC) barrier by crawling between neighboring EC. Whether EC regulate the integrity of their intercellular adhesive and junctional contacts in response to chemotaxing PMN is unresolved. EC respond to the binding of soluble mediators such as histamine by increasing their cytosolic free calcium concentration ([Ca++]i) (Rotrosen, D., and J.I. Gallin. 1986. J. Cell Biol. 103:2379-2387) and undergoing shape changes (Majno, G., S. M. Shea, and M. Leventhal. 1969. J. Cell Biol. 42:617-672). Substances such as leukotriene C4 (LTC4) and thrombin, which increased the permeability of EC monolayers to ions, as measured by the electrical resistance of the monolayers, transiently increased EC [Ca++]i. To determine whether chemotaxing PMN cause similar changes in EC [Ca++]i, human umbilical vein endothelial cells (HUVEC) maintained as monolayers were loaded with fura-2. [Ca++]i was measured in single EC during PMN adhesion to and migration across these monolayers. PMN-EC adhesion and transendothelial PMN migration in response to formyl-methionyl-leucyl-phenylalanine (fMLP) as well as to interleukin 1 (IL-1) treated EC induced a transient increase in EC [Ca++]i which temporally corresponded with the time course of PMN-EC interactions. When EC [Ca++]i was clamped at resting levels with a cell permeant calcium buffer, PMN migration across EC monolayers and PMN induced changes in EC monolayer permeability were inhibited. However, clamping of EC [Ca++]i did not inhibit PMN-EC adhesion. These studies provide evidence that EC respond to stimulated PMN by increasing their [Ca++]i and that this increase in [Ca++]i causes an increase in EC monolayer permeability. Such [Ca++]i increases are required for PMN transit across an EC barrier. We suggest EC [Ca++]i regulates transendothelial migration of PMN by participating in a signal cascade which stimulates EC to open their intercellular junctions to allow transendothelial passage of leukocytes.

The role of protected extracellular compartments in interactions between leukocytes, and platelets, and fibrin/fibrinogen matrices

Polymorphonuclear leukocytes express multiple surface receptors that mediate their adhesion to extracellular matrices and to other cells. These receptors also play roles in cell migration and phagocytosis. We have studied the role of one class of polymorphonuclear leukocytes surface receptors, the beta 2 integrins, in the interactions of these cells with fibrinogen. We have found that the beta 2 integrins, CD11b/CD18 (complement receptor three) and CD11c/CD18 mediate attachment of polymorphonuclear leukocytes to fibrinogen-coated surfaces. Polymorphonuclear leukocytes must be stimulated with chemoattractants, such as fMLP, or with cytokines, such as tumor necrosis factor to bind to fibrinogen via these integrins. Moreover, each of these integrins interacts with a different segment of the fibrinogen molecule. PMN adherence to fibrinogen via CD11b/CD18 depends on the carboxy terminus of fibrinogen, whereas adherence via CD11c/CD18 depends on the amino terminus of fibrinogen's alpha-chain. One of the physiological consequences of these interactions is that polymorphonuclear leukocytes stimulated with either chemoattractants or TNF form protected compartments at their interface with fibrinogen-coated surfaces and that elastase released into these compartments is inaccessible to protease inhibitors present in the plasma. These protected compartments exclude plasma proteins of > 40,000 daltons such as alpha 1 anti-proteinase, thereby allowing polymorphonuclear leukocyte proteases to degrade matrix proteins within this compartment without interference by plasma anti-proteinases.

Comparison of immunocytology to tissue culture for diagnosis of presumed herpesvirus dendritic epithelial keratitis

OBJECTIVE

The objective of this study is to prospectively compare the sensitivity and specificity of immunodetection of herpes simplex virus (HSV) in impression cytology specimens obtained directly from presumed herpesvirus dendritic epithelial keratitis with virus isolation by tissue culture of cells scraped from the same lesion.

METHODS

Corneal impression cytology and tissue culture were performed on 29 consecutive patients presenting with presumed herpesvirus dendritic epithelial keratitis during a 6-month period. Impression cytology of dendritic epithelial keratitis lesions with Millipore Biopore membranes were evaluated for the presence of antigens specific to HSV type I (HSV-1), HSV-2, and varicella-zoster virus (VZV) using monoclonal antibodies specific to these herpesviruses and immunofluorescent staining techniques.

RESULTS

Tissue culture was positive for HSV-1 in 52% (13 of 25) of dendritic epithelial keratitis patients without skin lesions, and was negative for VZV in 4 patients with dendritic epithelial keratitis and skin lesions in the distribution of the first division of the trigeminal nerve. The remaining 12 tissue cultures showed no cytopathic effect. Compared with tissue culture, impression cytology was 100% sensitive (13 of 13) and 92% specific (11 of 12) for the diagnosis of HSV-1 dendritic epithelial keratitis (Kappa coefficient of agreement 0.92). Although our sample size for VZV dendritic epithelial keratitis was small, the impression cytology findings correlated with our clinical diagnosis more often than tissue culture (2 of 4 versus 0 of 4).

CONCLUSION

Impression cytology allows simultaneous debridement of dendritic epithelial keratitis and, when combined with immunocytologic staining procedures, provides a simpler, more rapid, and less expensive alternative to tissue culture for the diagnosis of dendritic epithelial keratitis caused by HSV or VZV.

Cryopreserved cytoplasts from human neutrophils migrate across monolayers of human endothelial cells in response to a chemoattractant gradient

We have measured the capacity of two types of granule-poor anucleate cytoplasmic fragments (cytoplasts) from human polymorphonuclear leukocytes (PMN) to migrate across the barrier imposed by monolayers of human umbilical vein endothelial cells (EC) with and without chemotactic stimulation by fMLP. Cytoplasts were made by brief heating of PMN attached to surfaces (CKP) or by discontinuous gradient centrifugation (U-CYT). In the absence of chemoattractant, both types of cytoplast adhered poorly to endothelial cell monolayers, as did unstimulated intact PMN from which the cytoplasts were derived. In the presence of a transendothelial chemoattractant gradient both types of cytoplast exhibited a marked increase in adherence to, and migration across, endothelial monolayers; CKP did so to the same extent as chemoattractant-stimulated intact PMN. Since these motile cytoplasts are markedly deficient in most cytoplasmic organelles they may serve as useful tools for the dissection of cellular mechanisms that mediate PMN migration across endothelia.

Change of paracellular permeability of ocular surface epithelium by vitamin A deficiency

Dietary vitamin A deficiency in young rabbits caused advanced squamous metaplasia with keratinization of conjunctival epithelium and concomitant reduced paracellular permeability to 3H-mannitol. Both morphologic and permeability changes were reversed with systemic administration of vitamin A. In adult rabbits, vitamin A deficiency caused milder changes of goblet cell loss and increased cellular stratification in conjunction with reduced permeability in the conjunctiva-like epithelium that covers the vascularized cornea after chemical injury with n-heptanol. Topically applied retinoid (tretinoin 0.1%) did not affect the morphology and permeability of the normal corneal or conjunctival epithelium of rabbits that were not vitamin A deficient. These studies showed that altered permeability is associated with the epithelial abnormality during vitamin A deficiency and helped clarify the physiologic function of retinoids in the ocular surface epithelia in the nondeficient state.

Corneal epithelial wound healing in the absence of limbal epithelium

Corneal epithelial stem cells are thought to be at the limbus. The limbal epithelium was surgically removed in 12 New Zealand white rabbits. After 6 months, four showed mild vascularization. To challenge the remaining proliferative reserve, two consecutive 7.5-mm epithelial woundings were created 3 weeks apart in 11 limbal-deficient corneas and 11 controls. After the first wounding, five of the limbal-deficient corneas showed delayed healing, and seven became moderately vascularized; the controls healed normally. After the second wounding, eight experimental corneas showed intense vascularization; the controls did not. Recurrent erosions with delays in healing were noted in nine experimental animals but not in controls. Flat-mount preparation and impression cytology revealed centripetal migration of conjunctival epithelium with goblet cells onto the experimental corneas. These results indicate that only limited proliferative capacity of corneal epithelium remains in the absence of limbus. The constellation of delayed healing with recurrent erosion, corneal vascularization, and conjunctival epithelial ingrowth can be considered possible signs of limbal stem cell dysfunction.

Conjunctival cytologic features of primary Sjögren's syndrome

To determine whether there are specific cytologic features associated with primary Sjögren's syndrome (SS), the authors evaluated impression cytology specimens from three conjunctival sites (temporal bulbar [TB], inferior bulbar [IB], and inferior tarsal [IT]) from 38 SS eyes, 34 eyes of aqueous tear-deficient patients without SS, 35 eyes of seborrheic blepharitis patients, and 17 eyes of normal controls in a masked fashion. The following features were observed more frequently in SS eyes than in the eyes of the other groups: squamous metaplasia of the TB and IB (P less than 0.05), extensive (greater than 75%) goblet cell loss of the TB (P less than 0.05), mucous aggregates of the bulbar conjunctiva (P less than 0.05), and inflammatory cells intercalated with epithelial cells on the IT conjunctiva (P less than 0.06). The conjunctival inflammatory cell infiltrate correlated with the presence of extensive squamous metaplasia (P less than 0.01) in SS specimens. The inflammatory cells on the IT conjunctival epithelium were found to consist predominantly of T-lymphocytes by immunofluorescent staining of cytologic specimens from six eyes. Based on these findings, the authors speculated that conjunctival squamous metaplasia, in addition to aqueous tear deficiency, may be due to primary involvement of the dysfunctional immune system of SS.

Alteration of epithelial paracellular permeability during corneal epithelial wound healing

We studied the paracellular permeability to mannitol of corneas with epithelium of corneal, limbal, or conjunctival origin. Corneas with epithelial defects reepithelialized by corneal or limbal epithelium were nonvascularized; the corneal permeability was initially increased and returned to normal 3 days later. When epithelial defects extended beyond the limbus, they were healed by conjunctival epithelium. If corneas remained avascular or minimally vascularized, the conjunctiva-derived epithelium underwent a transdifferentiation process into a cornealike morphology in which the corneal permeability was initially increased upon complete reepithelialization, and gradually decreased to a level similar to that of normal cornea, 4 weeks after healing. However, when corneas became vascularized, the conjunctiva-derived epithelium retained its original phenotype, and corneal permeability remained increased throughout the 8-month period of study. The deranged barrier functions noted in the above vascularized cornea were demonstrated further by horseradish peroxidase tracer, which was found in the intercellular spaces of conjunctiva-derived epithelium of vascularized corneas but not in the avascular corneas with epithelia of corneal or limbal origin, or transdifferentiated conjunctival epithelium. To study further the effect of subsequent ocular surface trauma, conjunctival biopsy was performed on transdifferentiated avascular corneas 3 months after initial wounding. The biopsy resulted in extensive vascularization in three of eight previously nonvascularized corneas. Two weeks later, the corneal permeability was increased to a level similar to that of conjunctiva. These results indicate that corneal epithelial paracellular permeability correlates well with the status of the epithelial phenotype.

Paracellular permeability of corneal and conjunctival epithelia

The paracellular permeability of normal rabbit cornea and conjunctiva was studied in vivo and in vitro. After intravenous administration, horseradish peroxidase was found to percolate to the intercellular space of conjunctival epithelia and was restricted by the tight junctions of the superficial epithelium. Only minimal tracer was present in the limbus and cornea. The difference between corneal and conjunctival paracellular pathways was further compared in vitro by tissue perfusion studies using various tracers from subepithelial space to apical surface. The intact full-thickness cornea was permeable to mannitol (MW 182) but not to inulin or dextran. The conjunctiva was permeable to mannitol, inulin and FITC-dextran (MW 20,000). The quantitative permeability to 3H-mannitol (X10(-8) cm/sec) of adult rabbit cornea was 0.12 +/- 0.02, which is about 55-fold and 50-fold lower than that of conjunctiva (6.78 +/- 0.21) and peritoneum (6.12 +/- 0.63), respectively. Removal of the corneal epithelium increased the permeability 40-fold; however, removal of the endothelium had little effect on the solute permeation. When both corneal epithelium and endothelium were debrided, the bare stroma became edematous and the permeability increased 70-fold. The permeability of 1-week-old rabbit cornea was 1.32 +/- 0.18, which decreased to 0.46 +/- 0.06 in 2-week-old rabbits, and became similar to the adult level at 4 weeks of age. When Tenon's capsule was included in the perfusion, the conjunctival permeability decreased 2.5-fold. With the apposition of bare corneal stroma to the conjunctiva and Tenon's capsule, the permeability decreased further (4-fold).(ABSTRACT TRUNCATED AT 250 WORDS)

Open-label crossover study of vitamin A ointment as a treatment for keratoconjunctivitis sicca

The authors evaluated the efficacy of all-trans retinoic acid (vitamin A) ointment as a treatment for keratoconjunctivitis sicca (KCS) in a group of 11 patients selected on the basis of clinical history, slit-lamp examination results, rose Bengal staining, and tear film osmolarity. In this open-label crossover study, vitamin A ointment was no more effective than placebo in increasing tear secretion, as indicated by Schirmer test with proparacaine or tear film osmolarity, or in decreasing ocular surface disease, as indicated by rose Bengal staining. Seven patients stated some preference for the placebo ointment, two patients for the vitamin A ointment, and two patients had no preference.