Refractive errors in an urban population in Southern India: the Andhra Pradesh Eye Disease Study

PURPOSE

To assess the prevalence, distribution, and demographic associations of refractive error in an urban population in southern India.

METHODS

Two thousand five hundred twenty-two subjects of all ages, representative of the Hyderabad population, were examined in the population-based Andhra Pradesh Eye Disease Study. Objective and subjective refraction was attempted on subjects >15 years of age with presenting distance and/or near visual acuity worse than 20/20 in either eye. Refraction under cycloplegia was attempted on all subjects < or =15 years of age. Spherical equivalent >0.50 D in the worse eye was considered as refractive error. Data on objective refraction under cycloplegia were analyzed for subjects < or =15 years and on subjective refraction were analyzed for subjects >15 years of age.

RESULTS

Data on refractive error were available for 2,321 (92.0%) subjects. In subjects < or =15 years of age, age-gender-adjusted prevalence of myopia was 4.44% (95% confidence interval [CI], 2.14%-6.75%), which was higher in those 10 to 15 years of age (odds ratio, 2.75; 95% CI, 1.25-6.02), of hyperopia 59.37% (95% CI, 44.65%-74.09%), and of astigmatism 6.93% (95% CI, 4.90%-8.97%). In subjects >15 years of age, age-gender-adjusted prevalence of myopia was 19.39% (95% CI, 16.54%-22.24%), of hyperopia 9.83% (95% CI, 6.21%-13.45%), and of astigmatism 12.94% (95% CI, 10.80%-15.07%). With multivariate analysis, myopia was significantly higher in subjects with Lens Opacity Classification System HI nuclear cataract grade > or =3.5 (odds ratio, 9.10; 95% CI, 5.15-16.09), and in subjects with education of class 11 or higher (odds ratio, 1.80; 95% CI, 1.18-2.74); hyperopia was significantly higher in subjects > or =30 years of age compared with those 16 to 29 years of age (odds ratio, 37.26; 95% CI, 11.84-117.19), in females (odds ratio, 1.86; 95% CI, 1.33-2.61), and in subjects belonging to middle and upper socioeconomic strata (odds ratio, 2.10; 95% CI, 1.09-4.03); and astigmatism was significantly higher in subjects > or =40 years of age (odds ratio, 3.00; 95% CI, 2.23- 4.03) and in those with education of college level or higher (odds ratio, 1.73; 95% CI, 1.07-2.81).

CONCLUSIONS

These population-based data on distribution and demographic associations of refractive error could enable planning of eye-care services to reduce visual impairment caused by refractive error. If these data are extrapolated to the 255 million urban population of India, among those >15 years of age an estimated 30 million people would have myopia, 15.2 million hyperopia, and 4.1 million astigmatism not concurrent with myopia or hyperopia; in addition, based on refraction under cycloplegia, 4.4 million children would have myopia and 2.5 million astigmatism not concurrent with myopia or hyperopia.

Contact lens-induced peripheral ulcers with extended wear of disposable hydrogel lenses: histopathologic observations on the nature and type of corneal infiltrate

PURPOSE

Contact lens-induced peripheral ulcer (CLPU), a sudden-onset adverse event observed with extended wear of hydrogel lenses, is characterized by a single, small, circular, focal anterior stromal infiltrate in the corneal periphery or midperiphery. The condition is always associated with a significant overlying epithelial loss and resolves in a scar. The aim was to determine, by using histopathologic techniques, the nature and type of the corneal infiltrate of these events.

METHODS

Three CLPUs observed in three patients using disposable hydrogel lenses on an extended-wear schedule were examined. The eye was topically anesthetized, and a corneal section including all of the infiltrate was taken. A small triangular piece of conjunctiva immediately adjacent to the infiltrate was sectioned. The tissue was immediately fixed, processed, stained using hematoxylin and eosin and periodic acid-Schiff stains, and examined by using light microscopy.

RESULTS

The diameter of these three corneal infiltrates varied from 0.3 to 0.6 mm. Histopathology of the corneal sections revealed a focal epithelial loss corresponding to the infiltrated stroma in all three patients. The adjacent epithelium was thinned. Bowman's layer was intact in two patients and had a localized area of loss in the remaining patient. The anterior stroma was densely infiltrated with polymorphonuclear leukocytes and had focal areas of necrosis. The infiltration was most dense in the region immediately underlying Bowman's layer. No other infiltrative cell type was seen in any of the sections. Histopathology of the conjunctiva revealed features consistent with normal conjunctival tissue.

CONCLUSIONS

On histopathology of CLPU, distinctive features (i.e., focal corneal epithelial loss, an intact Bowman's membrane, and a localized infiltration of the anterior stroma with polymorphonuclear leukocytes) were seen. These features suggest that the event is an acute inflammatory process and probably noninfective in nature.

Adverse events with extended wear of disposable hydrogels: results for the first 13 months of lens wear

OBJECTIVE

To determine the type and incidence of adverse events seen in the first 13 months of extended wear from a prospective clinical trial involving the use of disposable hydrogels on a 6-night extended wear and replacement schedule.

DESIGN

A prospective, noncomparative clinical trial.

PARTICIPANTS

Three hundred thirty subjects were enrolled in the study from March 1993 to August 1996 and commenced in extended wear. The subjects were new contact lens users with ages ranging from 16 to 39 years and refractive errors from -1.00 to -6.50-diopter (D) sphere with cylindrical component less than 1.0 D.

INTERVENTION

Disposable hydrogel lenses on a 6-night extended wear and replacement schedule.

MAIN OUTCOME MEASURES

To determine the incidence of adverse events in the first 13 months of lens wear with the use of disposable hydrogels on an extended wear schedule. In addition, corneal infiltrative events observed with lens wear were classified based on their presenting signs and symptoms.

RESULTS

A total of 137 adverse events were seen in 102 subjects in the first 13 months of extended wear. The type of adverse events and the incidence per 100 patients per year of lens wear were as follows: corneal infiltrative events (44.4 events), contact lens papillary conjunctivitis (6.4 events), neovascularization and corneal wrinkling (1.7 events each), corneal striae and superior epithelial arcuate lesions (1.3 events each), and blepharokeratoconjunctivitis (0.4 event). Viral keratoconjunctivitis was also observed (0.8 event). The corneal infiltrative events were further subclassified as follows: contact lens-induced peripheral ulcers (13.6 events), contact lens-induced acute red eyes (12.3 events), infiltrative keratitis (9.7 events), and asymptomatic infiltrative events (8.9 events). There were no events of infectious keratitis. Except for all events of contact lens-induced peripheral ulcers and two isolated events of infiltrative keratitis that resulted in scarring, all of the corneal infiltrative events resolved without sequelae. None of the events caused any loss of best-corrected visual acuity.

CONCLUSIONS

Based on the observations from the first 13 months of extended wear in the trial, the majority of the complications associated with extended wear of disposable hydrogels are corneal infiltrative events. No events of microbial keratitis were seen in the first 13 months of extended wear. None of the events were associated with loss in best-corrected visual acuity. Clearly, frequent and regular disposing of lenses does not eliminate adverse effects, and better materials and designs are required for extended wear to be a successful method.

Population based assessment of diabetic retinopathy in an urban population in southern India

AIM

To assess the prevalence of diabetic retinopathy and the visual impairment caused by it in an urban population in southern India in order to determine its public health significance.

METHODS

2522 subjects (85.4% of those eligible), a representative sample of the population of Hyderabad city in southern India, underwent interview and detailed dilated eye examination during 1996-7 as part of the Andhra Pradesh Eye Disease Study.

RESULTS

124 subjects, all >/=30 years old, reported that they had diabetes, an age-sex adjusted prevalence of 7.82% (95% confidence interval (CI) 5.76-9.88%) in this age group. Diabetes was diagnosed at age >/=30 years in all but two subjects. The duration since diagnosis of diabetes was <10 years in 75.6% and >/=15 years in 6.7%. Diabetic retinopathy was present in 28 subjects, 1.78% (95% CI 1.09-2.48%) of those >/=30 years old. Most of the diabetic retinopathy was of the mild (50%) or moderate (39.3%) non-proliferative type; one subject (3.6%) had proliferative retinopathy. Multiple logistic regression revealed that the odds of having diabetic retinopathy were significantly higher in those >/=50 years than in those 30-49 years old (odds ratio 7.78, 95% CI 2.92-20. 73). Three subjects had visual impairment between 6/12 and 6/38 in either eye due to diabetic retinopathy, 0.19% (95% CI 0-0.41%) of those >/=30 years old.

CONCLUSION

Visual impairment due to diabetic retinopathy was relatively uncommon in this urban Indian population in 1996-7. However, this could change in the near future with an increase in duration of diabetes because of the anticipated aging of India's population and the recent suggestion of increase in diabetes prevalence in urban India, and therefore should be monitored.

Ciprofloxacin-resistant Pseudomonas keratitis

OBJECTIVE

To determine ciprofloxacin resistance of corneal isolates of Pseudomonas and to review the clinical response to topical therapy in cases of ciprofloxacin-resistant Pseudomonas keratitis, where medical therapy was begun with 0.3% ciprofloxacin.

DESIGN

Retrospective noncomparative case series.

PARTICIPANTS

Medical and microbiology records of 141 culture-proven cases of Pseudomonas keratitis, examined between January 1991 and June 1998, were reviewed retrospectively.

METHODS

All isolates of the Pseudomonas species from corneal scrapings were tested for their susceptibility to routinely used antibiotics by the Kirby-Bauer disc-diffusion method. The minimum inhibitory concentration of ciprofloxacin was determined by the agar-dilution method for most of the isolates found resistant to ciprofloxacin. Clinical response to initial therapy with 0.3% ciprofloxacin was determined in cases of keratitis caused by ciprofloxacin-resistant Pseudomonas.

MAIN OUTCOME MEASURES

Resistance of Pseudomonas isolates to ciprofloxacin and clinical response to initial therapy with 0.3% ciprofloxacin.

RESULTS

By use of the in vitro antimicrobial susceptibility test, 22 cases of keratitis caused by ciprofloxacin-resistant Pseudomonas were identified. The minimum inhibitory concentration of ciprofloxacin for these isolates was > or =16 microg/ml (mean = 43 microg/ml). Gentamicin resistance occurred in 63.6% of isolates also, but 90.9% ciprofloxacin-resistant isolates were susceptible to amikacin. Fifteen (76.7%) of 19 patients who initially received ciprofloxacin did not show any clinical improvement even after 3 days of intensive medical therapy. The infiltrate resolved in all 8 cases where the antibiotic therapy was modified on the basis of susceptibility test. Four eyes were subjected to penetrating keratoplasty, and three were eviscerated following failure of treatment with ciprofloxacin.

CONCLUSION

True resistance to ciprofloxacin is emerging in ophthalmology even among Pseudomonas isolates; therefore, the empiric treatment of infectious keratitis with ciprofloxacin monotherapy must be critically reviewed at this time.

Awareness of eye donation in an urban population in India

PURPOSE

Awareness of eye donation and willingness to pledge eyes for donation was assessed in the urban population of Hyderabad, India, where corneal blindness is a significant problem.

METHODS

A total of 2522 subjects of all ages, representative of the Hyderabad population, participated in the Andhra Pradesh Eye Disease Study. Subjects >15 years old were interviewed regarding awareness of eye donation and willingness to pledge eyes for donation.

RESULTS

Age-gender-adjusted prevalence of awareness of eye donation was 73.8% (95% CI: 66.5-81.0%) but only 1.9% (95% CI: 0.16-3.66%) had pledged eyes. With multivariate analysis, significantly less awareness of eye donation was found in illiterate subjects (OR 0.1; 95% CI: 0.1-0.14), subjects > or =70 years old (OR 0.3; 95% CI: 0.2-0.6), subjects of lower socio-economic status (OR 0.4; 95% CI: 0.3-0.6), females (OR 0.6; 95% CI: 0.5-0.8) and Muslims (OR 0.7; 95% CI: 0.6-0.9). Media was the major source of information about eye donation. Of those aware of eye donation, 44.9% were willing to pledge eyes. Willingness to pledge eyes for donation was significantly lower in Muslims (OR 0.18; 95% CI: 0.13-0.24) than in Hindus and in subjects > or =60years old (OR 0.3; 95% CI: 0.2-0.5).

CONCLUSIONS

These data show that although only a few had pledged eyes there is enough potential in this population for obtaining many more corneas for transplantation. The information about distribution and demographic associations of awareness and willingness for eye donation could help in developing strategies to increase procurement of corneas for dealing with corneal blindness.

Population-based assessment of the outcome of cataract surgery in an urban population in southern India

PURPOSE

To assess the outcome of cataract surgery in an urban population in southern India.

METHODS

As part of a population-based cross-sectional epidemiologic study, the Andhra Pradesh Eye Disease Study, 2,522 people of all ages, including 1,399 individuals 30 years of age or older, from 24 clusters representative of the population of Hyderabad in southern India underwent a detailed interview and ocular evaluation including logarithm of minimal angle of resolution (logMAR) visual acuity, refraction, slit-lamp biomicroscopy, applanation tonometry, gonioscopy, dilation, cataract grading, aphakia/pseudophakia status, and stereoscopic fundus evaluation. Automated threshold visual fields and slit-lamp and fundus photography were performed when indicated by standardized criteria. Very poor outcome in an eye that had undergone cataract surgery was defined as presenting distance visual acuity worse than 20/200, and poor outcome was defined as visual acuity worse than 20/60 to 20/200.

RESULTS

In subjects 50 years of age or older, after adjustment for age and sex distribution, the rate of having had cataract surgery in one or both eyes was 14.6% (95% confidence interval [CI], 11.4% to 17.8%). Of 131 eyes (91 subjects) that had undergone cataract surgery, 28 (21.4%; 95% CI, 14.4% to 28.4%) had very poor outcome and another 40 (30.5%; 95% CI, 22.6% to 38.4%) had poor outcome. The very poor outcome in 20 (71.4%) of 28 eyes and poor outcome in 23 (57.5%) of 40 eyes could be attributed to surgery-related causes or inadequate refractive correction. With multivariate analysis, very poor outcome as a result of surgery-related causes or inadequate refractive correction was more likely to be associated with intracapsular cataract extraction than with extracapsular cataract extraction (odds ratio, 9.34; 95% CI, 2.49 to 35.06) in subjects belonging to the lowest socioeconomic status (odds ratio, 4.92; 95% CI, 1.16 to 20.93) and with date of surgery 3 or fewer years before the survey than with more than 3 years (odds ratio, 4.52; 95% CI, 1.33 to 15.39). Also, very poor or poor outcome as a result of surgery-related causes or inadequate refractive correction was associated with women (odds ratio, 2.55; 95% CI, 1.06 to 6.16).

CONCLUSIONS

The very high rate of very poor and poor visual outcome, predominantly as a result of surgery-related causes and inadequate refractive correction, in this urban population of India suggests that more attention is needed to improve the visual outcome of cataract surgery. In order to deal with cataract-related visual impairment in India, as much emphasis on surgical quality, refractive correction, and follow-up care is necessary as on the number of surgeries.

Colonization of hydrogel lenses with Streptococcus pneumoniae: risk of development of corneal infiltrates

PURPOSE

To report the association between colonization of contact lenses with Streptococcus pneumoniae and the observation of corneal infiltrative events in a group of patients wearing disposable hydrogel lenses on an extended-wear schedule.

METHODS

In a prospective clinical trial, 330 patients wore disposable hydrogels on a 6-night extended-wear and replacement schedule. The contact lens, lid, and conjunctival microbiota of these subjects was analyzed at frequent intervals and at the time of an adverse event.

RESULTS

Streptococcus pneumoniae was an uncommon isolate and was recovered from only one of the 3,763 conjunctival samples, five (0.1%) of the 3,764 lid samples, and 33 (0.8%) of the 4,315 contact lens samples. Of the 33 lens samples, 10 (30%) were associated with corneal infiltrative events. Many of the events were mild inflammatory responses and resolved rapidly on discontinuation of lens wear. The presence of S. pneumoniae on the contact lens was associated with a significant risk of development of corneal infiltrates (odds ratio, 3.0; p = 0.0227, logistic-regression analysis).

CONCLUSIONS

Presence of S. pneumoniae on hydrogel lenses is a significant risk factor for the development of corneal infiltrates.

The transplantation of human fetal neuroretinal cells in advanced retinitis pigmentosa patients: results of a long-term safety study

The purpose of this study was to determine the long-term safety of transplanting human fetal neuroretinal cells (14 to 18 week gestational age) into a series of patients with advanced retinitis pigmentosa (RP). After obtaining informed consent, both hosts and mothers of donors were screened for transmissible diseases. Pre- and postoperative clinical exams, visual acuity, electroretinograms, and fluorescein angiograms were performed and visual field testing was attempted in each case. Surgically, an anterior approach through pars plana ciliaris was used. A retinotomy was performed in the paramacular area and a two-function cannula was introduced into the subretinal space to deliver a suspension of donor cells. The cell suspension carried approximately 4000 cells/microl; the volume injected did not exceed 150 microl. The patients were examined for periods ranging from 12 to 40 months posttransplantation. To date, no evidence of inflammation, infection, or overt rejection of the graft was noted in the host eye, neither was any change observed in the contralateral, unoperated eye. In conclusion, neuroretinal cells were injected into the subretinal space of 14 patients with advanced RP with no clinical appearance of detrimental effects at the time of surgery or up to 40 months postinjection except in 1 patient who developed retinal detachment. This sets the stage for a phase II clinical trial to determine the possible beneficial effects of this procedure in patients blinded by degenerative retinal disease.

Co-occurrence of pneumococcal keratitis and dacryocystitis

PURPOSE

To evaluate the specific risk factors responsible for the development of pneumococcal keratitis.

METHODS

In a retrospective analysis of 383 patients of culture-proven bacterial keratitis, seen between 1991 and 1995, 139 had monobacterial isolates on culture. We analyzed the various predisposing factors in these patients, with special emphasis on the patency of nasolacrimal drainage system.

RESULTS

Of the 139 patients with monobacterial keratitis, 48 (group 1) grew Streptococcus pneumoniae in culture. In the remaining 91 patients (group 2), Pseudomonas (18), coagulase-negative Staphylococci (15), Staphylococcus epidermidis (23), Staphylococcus aureus (16), Corynebacterium species (12), and others (seven) were isolated. Trauma was found to be a predisposing factor in 12 patients of group 1 and 27 patients of group 2 (p = 0.5601). Twelve (25%) patients of group 1 revealed chronic dacryocystitis, and nine of them underwent sac excision. On the contrary, only three patients of group 2 demonstrated dacryocystitis (p = 0.0003).

CONCLUSION

These results underscore the importance of assessing the patency of lacrimal drainage system in patients with infectious keratitis, especially of pneumococcal origin.

A potential role for extracellular signal-regulated kinases in prostaglandin F2alpha-induced protein synthesis in smooth muscle cells

To understand the mechanisms of prostaglandin F2alpha (PGF2alpha)-induced protein synthesis in vascular smooth muscle cells (VSMC), we have studied its effect on two major signal transduction pathways: mitogen-activated protein kinases and phosphatidylinositol 3-kinase (PI3-kinase) and their downstream targets ribosomal protein S6 kinase (p70(S6k)) and eukaryotic initiation factor eIF4E and its regulator 4E-BP1. PGF2alpha induced the activities of extracellular signal-regulated kinase 2 (ERK2) and Jun N-terminal kinase 1 (JNK1) groups of mitogen-activated protein kinases, PI3-kinase, and p70(S6k) in a time-dependent manner in growth-arrested VSMC. PGF2alpha also induced eIF4E and 4E-BP1 phosphorylation, global protein synthesis, and basic fibroblast growth factor-2 (bFGF-2) expression in VSMC. Whereas inhibition of PI3-kinase by wortmannin completely blocked the p70(S6k) activation, it only partially decreased the ERK2 activity, and had no significant effect on global protein synthesis and bFGF-2 expression induced by PGF2alpha. Rapamycin, a potent inhibitor of p70(S6k), also failed to prevent PGF2alpha-induced global protein synthesis and bFGF-2 expression, although it partially decreased ERK2 activity. In contrast, inhibition of ERK2 activity by PD 098059 led to a significant loss of PGF2alpha-induced eIF4E and 4E-BP1 phosphorylation, global protein synthesis, and bFGF-2 expression. PGF2alpha-induced phosphorylation of eIF4E and 4E-BP1 was also found to be sensitive to inhibition by both wortmannin and rapamycin. These findings demonstrate that 1) PI3-kinase-dependent and independent mechanisms appear to be involved in PGF2alpha-induced activation of ERK2; 2) PGF2alpha-induced eIF4E and 4E-BP1 phosphorylation appear to be mediated by both ERK-dependent and PI3-kinase-dependent rapamycin-sensitive mechanisms; and 3) ERK-dependent eIF4E phosphorylation but not PI3-kinase-dependent p70(S6k) activation correlates with PGF2alpha-induced global protein synthesis and bFGF-2 expression in VSMC.

Treatment outcome of Moraxella keratitis: our experience with 18 cases--a retrospective review

PURPOSE

To analyze the clinical presentation, predisposing risk factors, in vitro antimicrobial susceptibility, and especially the outcome of therapy of Moraxella keratitis.

METHODS

Retrospective review of 18 culture-proven cases of Morarella keratitis.

RESULTS

Morarella keratitis was associated with Hansen's disease, uncontrolled diabetes mellitus, herpes zoster ophthalmicus, and chickenpox of the recent past and severe protein energy malnutrition. Other associated ocular conditions included lagophthalmos, blepharitis, steroid therapy, corneal degeneration, and scleritis. In four patients, no systemic or ocular predisposing factors could be identified. Three patients presented with an indolent peripheral, anterior stromal infiltrate while the remaining patients showed a central or paracentral ulceration with or without hypopyon. Moraxella species was the only pathogen isolated in 11 cases, whereas mixed infection was seen in seven cases. All isolates were sensitive to ciprofloxacin. Eight of 18 strains of Moraxella were resistant to cefazolin. All 14 eyes for which the follow-up data were available responded to medical treatment alone.

CONCLUSIONS

Although considered to be associated with poor outcome, our experience suggests that a favorable outcome can be expected in Moraxella keratitis. Cefazolin resistance (as seen in our series) may pose a problem and, hence, monitoring of antimicrobial susceptibility would be beneficial. In view of cefazolin resistance, ciprofloxacin monotherapy appears to be an effective method in the medical management of these cases.

Burden of moderate visual impairment in an urban population in southern India

OBJECTIVE

To assess the prevalence and causes of moderate visual impairment in an urban population in southern India.

DESIGN

Population-based, cross-sectional study.

PARTICIPANTS

A total of 2522 (85.4% of the eligible) persons of all ages, including 1399 persons 30 years of age or older, from 24 clusters representative of the population of Hyderabad city.

TESTING

The eligible subjects underwent a detailed ocular evaluation, including logarithm of the minimum angle of resolution (logMAR) visual acuity, refraction, slit-lamp biomicroscopy, applanation tonometry, gonioscopy, cataract grading, and stereoscopic dilated fundus evaluation. Automated threshold visual fields and slit-lamp and fundus photography were done when indicated by standardized criteria.

MAIN OUTCOME MEASURE

Moderate visual impairment was defined as presenting distance visual acuity less than 20/40 to 20/200 or visual field loss by predefined standardized conservative criteria in the better eye.

RESULTS

In addition to the 1% prevalence of blindness in this sample reported earlier, moderate visual impairment was present in 303 subjects, an age-gender-adjusted prevalence of 7.2% (95% confidence interval [CI], 4.5%-9.9%; design effect, 2.7). The major cause of moderate visual impairment was refractive error (59.4%, 95% CI, 52.3%-66.5%) followed by cataract (25.3%, 95% CI, 19%-31.6%). Multivariate analysis showed that the prevalence of moderate visual impairment was significantly higher in those 40 years of age or older (odds ratio, 10.9; 95% CI, 8-15) and females (odds ratio, 1.89; 95% CI, 1.41-2.53) and lower in those belonging to the highest socioeconomic status (odds ratio, 0.27; 95% CI, 0.14-0.51). However, because of the pyramidal age distribution of the population, 38.1% of the total moderate visual impairment was present in those younger than 40 years of age. The proportion of moderate visual impairment caused by refractive error was higher in the younger than in the older age groups (P < 0.0001).

CONCLUSIONS

Projecting the results to the 26.5% urban population of India, there would be 18.4 million (95% CI, 11.5-25.2 million) persons with moderate visual impairment in urban India alone. Refractive error was the major cause of moderate visual impairment in the population studied. The absolute proportion of moderate visual impairment in those younger than 40 years of age was considerable. The eyecare policy of India, apart from dealing with blindness, should address the issue of the relatively easily treatable uncorrected refractive error as the cause of moderate visual impairment in an estimated 10.9 million persons in urban India.

JunB forms the majority of the AP-1 complex and is a target for redox regulation by receptor tyrosine kinase and G protein-coupled receptor agonists in smooth muscle cells

To understand the role of redox-sensitive mechanisms in vascular smooth muscle cell (VSMC) growth, we have studied the effect of N-acetylcysteine (NAC), a thiol antioxidant, and diphenyleneiodonium (DPI), a potent NADH/NADPH oxidase inhibitor, on serum-, platelet-derived growth factor BB-, and thrombin-induced ERK2, JNK1, and p38 mitogen-activated protein (MAP) kinase activation; c-Fos, c-Jun, and JunB expression; and DNA synthesis. Both NAC and DPI completely inhibited agonist-induced AP-1 activity and DNA synthesis in VSMC. On the contrary, these compounds had differential effects on agonist-induced ERK2, JNK1, and p38 MAP kinase activation and c-Fos, c-Jun, and JunB expression. NAC inhibited agonist-induced ERK2, JNK1, and p38 MAP kinase activation and c-Fos, c-Jun, and JunB expression except for platelet-derived growth factor BB-induced ERK2 activation. In contrast, DPI only inhibited agonist-induced p38 MAP kinase activation and c-Fos and JunB expression. Antibody supershift assays indicated the presence of c-Fos and JunB in the AP-1 complex formed in response to all three agonists. In addition, cotransfection of VSMC with expression plasmids for c-Fos and members of the Jun family along with the AP-1-dependent reporter gene revealed that AP-1 with c-Fos and JunB composition exhibited a higher transactivating activity than AP-1 with other compositions tested. All three agonists significantly stimulated reactive oxygen species production, and this effect was inhibited by both NAC and DPI. Together, these results strongly suggest a role for redox-sensitive mechanisms in agonist-induced ERK2, JNK1, and p38 MAP kinase activation; c-Fos, c-Jun, and JunB expression; AP-1 activity; and DNA synthesis in VSMC. These results also suggest a role for NADH/NADPH oxidase activity in some subset of early signaling events such as p38 MAP kinase activation and c-Fos and JunB induction, which appear to be important in agonist-induced AP-1 activity and DNA synthesis in VSMC.

Differential regulation of p27kip1 levels and CDK activities by hypertrophic and hyperplastic agents in vascular smooth muscle cells

To understand the molecular mechanisms that determine the fate of a cell to undergo either hypertrophy or hyperplasia, we studied the effects of angiotensin II (Ang II) and platelet-derived growth factor (PDGF)-BB, hypertrophic and hyperplastic agents, respectively, on the modulation of G1/S transition molecules in smooth muscle cells. Ang II increased protein synthesis while PDGF-BB induced both DNA and protein synthesis. Ang II had no significant effect on the steady-state levels of cyclin-dependent kinase (CDK) inhibitor (CDKI), p27kip1, and on the activities of CDK2 and CDK4, although it caused a modest increase in cyclin E levels. In contrast, PDGF-BB induced depletion of p27kip1 and increased cyclins D1 and E levels and CDK2 and CDK4 activities. Reflecting its lack of effect on CDK activities, Ang II failed to phosphorylate tumor suppressor retinoblastoma protein, Rb. PDGF-BB, on the other hand, induced phosphorylation of Rb, consistent with its ability to activate CDKs. Together, these findings suggest that Ang II-induced hypertrophy may be due to its failure to activate cellular signaling events required for G1/S transition.

Whole body bone mass and body composition in a girl with achondroplasia, at ages 9 through 12

A 9-yr-old white female with achondroplasia was one of a group of 773 children who were recruited for a study of the accumulation of whole body skeletal mass during four annual measurements. Measurements of bone, fat, and lean mass were obtained with a Hologic 1000W instrument. The following variables are used to compare the subject with the 130 healthy white girls who participated in the study: bone mineral content (BMC), bone mineral density (BMD), and bone mineral apparent density (BMAD). Ratios of BMC to weight or BMC to height, and BMD to weight or height, were also calculated. We found that the BMC of the subject was lower when compared to the reference group, but the ratios of BMC to weight or BMC to height were similar in both. BMD was also lower in the patient, but, when expressed in relation to height and weight, the ratios were similar or slightly higher in the case. BMAD was higher in the subject with achondroplasia at all ages. The subject had a lower percentage fat and higher percentage lean mass than the reference children. We conclude that the accumulation of bone mass in this subject with achondroplasia is appropriate for her reduced body size.

Adherence of Acanthamoeba to human corneal epithelial cells recovered from normal non-lens wearers and asymptomatic contact lens wearers

To increase our knowledge of factors leading to Acanthamoeba keratitis in contact lens wearers, we determined the ability of this organism to adhere to corneal epithelial cells (EC) recovered from non-lens wearers (NL) and from subjects using hydrogel contact lenses on a daily (DW) and extended wear (EW) schedule. ECs were incubated with trophozoites of Acanthamoeba and, after 3 h, the median per cent of cells exhibiting adherence was 24, 23 and 23 for NL, DW and EW groups respectively (P=0.552, Kruskal-Wallis Test). There were no differences between the groups for the number of adherent amoebae and a significant majority had only one adherent trophozoite per EC. No difference in adherence was seen with increasing exposure time. Factors other than amoebic adherence to superficial corneal EC are responsible for the increased incidence of Acanthamoeba keratitis in lens wearers.

In vitro susceptibility of bacterial keratitis pathogens to ciprofloxacin. Emerging resistance

OBJECTIVE

To examine in vitro susceptibility of bacterial keratitis pathogens to ciprofloxacin.

DESIGN

Retrospective review.

PARTICIPANTS

The authors examined in vitro susceptibility of 1558 corneal isolates from 1303 patients with culture-proven bacterial keratitis seen at the LV Prasad Eye Institute in Hyderabad, India, during the 6-year period between March 1, 1991, and June 30, 1997.

RESULTS

Of 1558 corneal isolates, 478 (30.7%) were not sensitive to ciprofloxacin. Among the isolates, 355 (32.5%) of the 1091 gram-positive cocci were not sensitive to ciprofloxacin, and 2 (10%) of the 20 gram-positive bacilli, 22 (13.3%) of the 165 gram-negative organisms, and 99 (35.1%) of the 282 Actinomycetes and related organisms were not sensitive to ciprofloxacin. Results from chi-square for trends analysis showed a trend of significantly increasing ciprofloxacin insensitivity in bacteria between 1992 and 1997 (P = 0.011).

CONCLUSION

This is the first report of significantly increasing ciprofloxacin insensitivity among corneal pathogens. Although the lowered cost and convenience of dispensing a single, commercially available antibiotic such as ciprofloxacin in the initial treatment of bacterial keratitis is desirable, the emergence of ciprofloxacin resistance is a significant finding in this series, and the clinician should proceed with caution in the initial empiric treatment of bacterial keratitis with ciprofloxacin.

Developing a model to reduce blindness in India: The International Centre for Advancement of Rural Eye Care

With the continuing high magnitude of blindness in India, fresh approaches are needed to effectively deal with this burden on society. The International Centre for Advancement of Rural Eye Care (ICARE) has been established at the L.V. Prasad Eye Institute in Hyderabad to develop such an approach. This paper describes how ICARE functions to meet its objective. The three major functions of ICARE are design and implementation of rural eye-care centres, human resource development for eye care, and community eye-health planning. ICARE works with existing eye-care centres, as well as those being planned, in underserved areas of India and other parts of the developing world. The approach being developed by ICARE, along with its partners, to reduce blindness is that of comprehensive eye care with due emphasis on preventive, curative and rehabilitative aspects. This approach involves the community in which blindness is sought to be reduced by understanding how the people perceive eye health and the barriers to eye care, thereby enabling development of strategies to prevent blindness. Emphasis is placed on providing good-quality eye care with attention to reasonable infrastructure and equipment, developing a resource of adequately trained eye-care professionals of all cadres, developing a professional environment satisfactory for patients as well as eye-care providers, and the concept of good management and financial self-sustainability. Community-based rehabilitation of those with incurable blindness is also part of this approach. ICARE plans to work intensively with its partners and develop these concepts further, thereby effectively bringing into practice the concept of comprehensive eye care for the community in underserved parts of India, and later in other parts of the developing world. In addition, ICARE is involved in assessing the current situation regarding the various aspects of blindness through well-designed epidemiologic studies, and projecting the eye-care needs for the future with the help of reliable information. With balanced attention to infrastructure, manpower, financial self-sustenance, and future planning, ICARE intends to develop a practical model to effectively reduce blindness in India on a long-term basis.

HPLC analysis of closed, open, and reflex eye tear proteins

Changes in the closed, open and reflex eye tear proteins of normal subjects were compared and analysed. Tear proteins were resolved by high-performance liquid chromatography (HPLC) utilising both gel filtration (P-300 SW) and reverse-phase (C-18) columns and the HPLC fractions were further analysed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) under reducing and non-reducing conditions. The protein composition of the closed-eye tear was significantly different from that of the open and reflex-eye tear. Secretory IgA (sIgA) was the predominant protein in closed eye tears constituting 49% of the total protein compared to 11% in reflex tears, whereas lysozyme was the predominant protein (53%) in reflex tears. Levels of lactoferrin, lipocalin and lysozyme were relatively constant in both open and reflex tears. HPLC profiles of the closed-eye tears, upon continuous stimulation of lacrimal glands indicated that sIgA was significantly reduced whereas lactoferrin, lipocalin, and lysozyme were significantly increased. These results indicate that the tear composition upon waking attains that of the open eye within 4 to 5 minutes, and upon continuous stimulation this reflects the reflex-eye tear composition. It also indicates that mechanisms responsible for changes in concentration of constitutive and regulated tear protein with stimulus can be studied successfully using non-invasive methods to collect human tears.

Prospective evaluation of corneal endothelial cell loss after pediatric cataract surgery

PURPOSE

To study the alterations in endothelial cell count and morphology after pediatric cataract surgery using currently practiced techniques.

SETTING

L.V. Prasad Eye Institute, Hyderabad, India.

METHODS

In a prospective nonrandomized series comprising 20 eyes of 14 children with congenital or developmental cataract, endothelial cell loss from cataract surgery was evaluated. Mean patient age was 9.3 years (range 5 to 15 years). Extracapsular cataract extraction (ECCE) with intraocular lens (IOL) implantation was performed in 11 eyes (Group 1). Primary posterior capsulotomy and anterior vitrectomy were performed with ECCE and IOL implantation in 9 eyes (Group 2). Noncontact specular microscopy was done preoperatively and 6 to 8 and 24 to 36 weeks postoperatively. Endothelial cell loss, alteration in the coefficient of variation, and the change in the number of hexagonal cells were determined by semiautomated analysis of endothelial pictures.

RESULTS

Mean endothelial cell loss was 198.39 cells/mm2 (5.28%) in Group 1 and 295.17 cells/mm2 (7.50%) in Group 2 at 24 to 36 weeks. There was no statistically significant difference in alteration in endothelial cell count and morphology between the 2 groups.

CONCLUSIONS

The results suggest that endothelial cell loss with currently practiced techniques of pediatric cataract surgery is within acceptable limits.

Autosomal dominant zonular cataract with sutural opacities is associated with a splice mutation in the betaA3/A1-crystallin gene

PURPOSE

Congenital cataracts constitute a morphologically and genetically heterogeneous group of diseases that are a major cause of childhood blindness. Autosomal Dominant Zonular Cataracts with Sutural Opacities (CCZS) have been mapped to chromosome 17q11-q12 near the betaA3A1-crystallin gene (CRYBA1). The betaA3A1-crystallin gene was investigated as the causative gene for the cataracts.

METHODS

The betaA3/A1-crystallin gene was sequenced in affected and control individuals. Base changes were confirmed and assayed in additional family members and controls using NlaIII restriction digestion of PCR amplified DNA sequences. Base changes were assessed for their effects on splicing by information analysis.

RESULTS

The cataracts are associated with a sequence change in the 5' (donor) splice site of intron 3: GC(g->a)tgagt. The sequence change also creates a new NlaIII site. This base change cosegregates with the cataracts in this family, being present in every affected individual. Conversely, this base change was not seen in 140 chromosomes examined in 70 unaffected and unrelated individuals. Information theory mutational analysis shows that the base change lowers the information content of the splice site from 6.0 to -6.8 bits, so that splicing would not be expected to occur at the altered site.

CONCLUSIONS

Taken together, these observations suggest that the observed mutation might be causally related to the cataracts in this family.

cAMP inhibits linoleic acid-induced growth by antagonizing p27(kip1) depletion, but not interfering with the extracellular signal-regulated kinase or AP-1 activities

To understand the underlying signaling events of polyunsaturated fatty acid-induced growth, we studied the effect of cAMP on early and delayed growth response events induced by linoleic acid in smooth muscle cells (SMC). cAMP significantly inhibited both basal and linoleic acid-induced DNA synthesis. Linoleic acid-induced early growth response events, such as activation of ERKs, induction of expression of c-fos and jun-B and stimulation of AP-1 activity, however, were not affected by cAMP. In contrast, linoleic acid-induced c-jun expression was blocked by cAMP. cAMP alone stimulated ERKs activation, c-fos and jun-B expression and increased AP-1 activity. Linoleic acid induced depletion of p27kip1 and increased CDK2 activity, events required for G1/S transition. In contrast to early growth response events, linoleic acid-induced G1/S transition signals were significantly inhibited by cAMP. These findings suggest that in addition to inducing immediate early growth response events, linoleic acid mimics growth factors in activating cell cycle events that are associated with G1/S transition in SMC and the negative regulation of linoleic acid-induced growth by cAMP is apparently due to its antagonism with linoleic acid-induced p27kip1 depletion and CDK2 activation.

Effect of storage on protein concentration of tear samples

PURPOSE

To determine the effect of storage on protein concentration of tear samples stored at room temperature (RT), 4 degrees C, -20 degrees C and -70 degrees C.

METHODS

Total protein concentration of closed, open (basal tears) and reflex tears (stimulated tears) was measured by modified Bradford's method. SDS-PAGE gel electrophoresis was used to determine the intensity of protein bands. Quantity of various tear proteins was determined by HPLC analysis.

RESULTS

Compared to control samples (0 h) protein concentrations decreased significantly in tear samples stored beyond 4 h (for closed) and 8 h (for open and reflex) at RT. However, no significant change in protein concentrations was observed in closed and reflex tears when stored up to 1 week at 4 degrees C, up to 2 months at -20 degrees C; and up to 4 months at -70 degrees C. Multiple freeze-thaw procedures (6 x per day at 2 h intervals) resulted in 8% decrease (at -20 degrees C) and 10% decrease (at -70 degrees C) of protein concentrations in closed eye tears. SDS-PAGE analysis of tear samples stored at -20 degrees C and -70 degrees C for 4 months greatly affected the intensity of the protein bands. HPLC analysis of tear samples stored at these conditions showed the significant reduction in the peak corresponding to secretory IgA in closed eye tears and a split in the peak corresponding to lysozyme in case of reflex tears.

CONCLUSIONS

Reduction in the total protein concentration, intensity of the protein bands as well as changes in the quantity of tear proteins were observed in the tear samples stored for longer duration of time at various temperatures.