PubMed Health⌕ Search

Biomedical subjects

M A Latina

Publications and source records attributed to M A Latina.

At least 19 recordsLinked to original sources
PubMed2000

Complications of glaucoma drainage implant surgery.

Glaucoma drainage implants play an important role in the management of refractory glaucoma. It may be considered as a primary procedure in eyes with severe scarring of the conjunctiva and the limbus, neovascularization, multiple previous, failed filtering procedures, and severely glaucomatous eyes for which corneal graft is planned. Recommendations have been made regarding improving the biocompatibility of the materials used in the manufacture of these implants. The current state of development of glaucoma drainage implants is likened to that of intraocular lenses in the 1970s. Further development of devices and techniques will only serve to improve our armamentarium and success against glaucoma, specifically refractory glaucoma. Glaucoma posterior tube shunts have proved to be safe, with the majority of complications either nonsight-threatening, spontaneously resolving, or reversible. Considered primarily in the most severe cases of refractory glaucoma, it has otherwise changed the outlook for such patients.

Filtering Surgery↗
PubMed1998

Apoptosis and morphologic changes in drug-treated trabecular meshwork cells in vitro.

Using an in vitro culture system, we investigated whether bovine trabecular meshwork cells undergo apoptosis (programmed cell death) following exposure to anti-glaucoma medications (timolol, pilocarpine and epinephrine) and known inducers of apoptosis (5-fluorouracil, mitomycin-C and dexamethasone). Third to fifth passage bovine trabecular meshwork cells were grown to confluence and incubated for 1-12 days in growth media with timolol (1-1000 microM), pilocarpine (15-15,000 microM), epinephrine (5-5000 microM), 5-fluorouracil (10-100 micrograms ml-1), mitomycin-C (0.01-100 micrograms ml-1) and dexamethasone (0.01-100 microM). The cultures were evaluated for apoptosis by phase-contrast microscopy, transmission electron microscopy and in situ apoptosis labeling. 5-Fluorouracil (10-100 micrograms ml-1), mitomycin-C (0.1-100 micrograms ml-1) and epinephrine (500-5000 microM) induced apoptosis in a dose and time-dependent manner. Timolol, pilocarpine, and dexamethasone-treated specimens did not show evidence of apoptosis at any of the concentrations tested. Trabecular meshwork cells incubated in timolol (100-1000 microM) developed cytoplasmic granules, and specimens treated with pilocarpine (15,000 microM) developed cytoplasmic vacuoles. These granules and vacuoles have the appearance of secondary lysosomes. Dexamethasone-treated cells developed an increased number of mitochondria. This study suggests that the trabecular meshwork may undergo apoptosis following exposure to 5-fluorouracil, mitomycin-C and epinephrine. Timolol, pilocarpine and dexamethasone did not induce apoptosis. However, these drugs can incite characteristic morphologic changes in cultured trabecular meshwork cells.

Animals↗
PubMed1998

Q-switched 532-nm Nd:YAG laser trabeculoplasty (selective laser trabeculoplasty): a multicenter, pilot, clinical study.

OBJECTIVE: To investigate the safety and efficacy of a new laser procedure using a q-switched 532-nm neodymium (Nd):YAG laser, also called "selective laser trabeculoplasty," to lower intraocular pressure (IOP) in patients with open-angle glaucoma (OAG). The laser parameters were set to selectively target pigmented trabecular meshwork (TM) cells without coagulative damage to the TM structure or nonpigmented cells. DESIGN: Nonrandomized, prospective, clinical trial. PARTICIPANTS: Thirty eyes of 30 patients with uncontrolled OAG (OAG group) and 23 eyes of 23 patients with uncontrolled OAG treated previously with argon laser trabeculoplasty (ALT group) were observed for 4 to 26 weeks. Forty-four of the 53 eyes were observed for 26 weeks. INTERVENTION: Patients were treated with the Coherent Selecta 7000 (Coherent, Inc, Palo Alto, CA) frequency-doubled q-switched Nd:YAG laser (532 nm). A total of approximately 50 nonoverlapping spots were placed over 180 degrees of the TM at energy levels ranging from 0.6 to 1.2 mJ per pulse. After surgery, patients were maintained with the identical drug regimen as that before treatment. RESULTS: Both the OAG and ALT groups showed similar IOP reductions over time. Seventy percent of patients in each group responded to treatment with an IOP reduction of least 3 mmHg. At 26 weeks of follow-up, mean IOP reduction was 5.8 mmHg (23.5%, P < 0.001) for the OAG group and 6.0 mmHg (24.2%, P < 0.001) for the ALT group. The untreated eye showed a 9.7% (P < 0.001) reduction of IOP at 26 weeks. However, the IOP difference between the treated and untreated eyes was statistically significant at P < 0.003. Transient IOP elevation of 5 mmHg or greater was seen in 24% of patients. CONCLUSION: The selective laser trabeculoplasty appears to be a safe and effective method to lower IOP in patients with OAG and patients treated previously with ALT. A reduction of IOP can be achieved without coagulation of the TM.

Adult↗
PubMed1998

Chorioretinal folds following glaucoma valve implantation.

Glaucoma valve implants have been observed to cause scleral indentation and flattening. The authors report the case of a 79-year-old woman who had previously undergone glaucoma valve implantation, and who subsequently developed chorioretinal folds that corresponded to the implant in location and configuration. Accumulation of fluid behind the implant, as documented by B-scan ultrasonography, appeared to result in the observed scleral and chorioretinal changes. The authors conclude that chorioretinal folds can result following glaucoma valve implantation.

Aged↗
PubMed1997

The use of processed pericardium in the repair of corneo-scleral fistulas.

Explantation of glaucoma valve implants may be complicated by wound closure problems. Prolonged implantation of these valves can lead to development of corneo-scleral fistulas that may not be adequately sealed with the use of sutures alone. The authors report the use of processed pericardium as tissue replacement material for the repair of such fistulas. A 45-year-old woman underwent explantation of a Baerveldt glaucoma valve implant, resulting in the development of a corneo-scleral fistula. To repair the fistula, processed pericardium was inserted into it and secured with 10-0 nylon sutures. Postoperatively, a good wound seal was achieved with no leakage of aqueous humor from the anterior chamber, nor any inflammation. Processed pericardium appears to be an effective tissue replacement material for sealing corneo-scleral fistulas.

Corneal Diseases↗
PubMed1995

Selective targeting of trabecular meshwork cells: in vitro studies of pulsed and CW laser interactions.

The purpose of the present study was to selectively target pigmented trabecular meshwork cells without producing collateral damage to adjacent non-pigmented cells or structures. The ability to selectively target trabecular meshwork cells without coagulation, while preserving the structural integrity of the meshwork, could be a useful approach to study whether the biological response of non-coagulative damage to the trabecular meshwork and trabecular meshwork cells is similar to that seen with coagulative damage to the trabecular meshwork which occurs with argon laser trabeculoplasty. This approach also may be useful to non-invasively deplete trabecular meshwork cells while preserving the structural integrity of the trabecular meshwork in an animal model. A mixed cell culture of pigmented and non-pigmented trabecular meshwork cells were irradiated with Q-switched Nd-YAG and frequency-doubled Nd-YAG lasers, microsound pulsed dye-lasers, and an argon ion laser in order to define a regime where laser absorption would be confined to pigmented trabecular meshwork cells, thereby permitting selective targeting of these cells without producing collateral thermal damage to adjacent non-pigmented cells. Pulse durations ranged from 10 nsec to 0.1 sec. A fluorescent viability/cytotoxicity assay was used to evaluate laser effects and threshold energies, and cells were examined morphologically by light and TEM. Selective targeting of pigmented trabecular meshwork cells was achieved with pulse durations between 10 nsec and 1 microsec and 1 microsec without producing collateral thermal or structural damage to adjacent non-pigmented trabecular meshworks cells when examined by light and transmission electron microscopy. Pulse durations greater than 1 microsec resulted in non-selective killing of non-pigmented trabecular meshwork cells. Threshold radiant exposures were as low as 18 mJ cm-2, and increased at longer wavelengths, longer pulse durations and lower melanin contents within the cells. It is concluded that selective targeting of pigmented trabecular meshwork cells can be achieved using pulsed lasers with low threshold radiant exposures avoiding collateral thermal damage to adjacent non-pigmented trabecular meshwork cells. This approach can be readily applied in vivo.

Cell Survival↗
PubMed1995

Clinical experience with the Baerveldt glaucoma drainage implant.

PURPOSE: To assess clinical outcomes in patients who were treated with the Baerveldt glaucoma drainage implant. METHODS: The authors performed a retrospective multicenter study of 100 patients (103 eyes) with medically uncontrollable glaucomas who underwent a one-stage implantation with either the 200-, 250-, 350-, or 500-mm2 Baerveldt implant. The authors defined surgical success as 5 mmHg less than intraocular pressure less than 22 mmHg without additional glaucoma surgery and without loss of light perception. RESULTS: With a mean follow-up of 13.6 +/- 0.9 months (range, 4-37 months), 74 eyes (71.8%) had successful outcomes. Cumulative life-table success rates were 90.3% at 3 months (n = 103), 72.6% at 6 months (n = 84), and 60.3% at 24 months (n = 34). Intraocular pressure (IOP) was reduced from a mean of 38.5 +/- 1.4 mmHg with 2.2 +/- 0.1 antiglaucoma medications to 15.1 +/- 0.8 mmHg (P < 0.0005) with 0.5 +/- 0.1 antiglaucoma medications (P < 0.0005). Visual acuity was improved or remained within one line of the preoperative visual acuity in 90 eyes (87.4%). Complications occurred in 74 eyes (71.8%). A significant portion of these complications (45%) was transient, resolving without any intervention. Only 8% were serious sight-threatening complications. The most common complications included shallow anterior chamber or hypotony (32%), choroidal effusion or hemorrhage (20.4%), corneal decompensation or edema (17.5%), hyphema (14.1%), and tube obstruction (12.6%). CONCLUSION: The Baerveldt implant is effective in lowering the IOP in patients with intractable glaucomas. Hypotony and other complications are common, which also have been reported in other nonvalved glaucoma drainage implants. However, the majority of these complications did not affect surgical outcome.

Adolescent↗
PubMed1993

Effects of gamma-interferon on human trabecular meshwork cell phagocytosis.

PURPOSE: Gamma-interferon (G-IFN) regulates a variety of immune responses including the modulation of the phagocytic response and induction of class II major histocompatibility complex antigens. Because human trabecular meshwork (HTM) cells in culture are known to be actively phagocytic and have been shown to express class II major histocompatibility complex antigens, the effects of G-IFN on HTM cells were examined. METHODS: Confluent HTM cells were incubated in media (Dulbecco's modified Eagle's medium +10% fetal bovine serum) containing 0, 10, 50, 100, 500, 1000, or 5000 units/ml of recombinant human G-IFN for 72 hr. After incubation, the cultured HTM cells were challenged with 5 ml of media containing 1 x 10(8) fluorescein labeled microspheres/ml. Phagocytic uptake was determined by flow cytometry. RESULTS: Flow cytometric analysis of microsphere uptake shows that G-IFN inhibited HTM cell phagocytosis of microspheres in a dose-dependent fashion. At 5000 units/ml of G-IFN, phagocytosis of microspheres was inhibited by 64.5 +/- 2.4% compared to control (P < 0.007). The half maximal dose of phagocytic inhibition is < 10 units/ml. Increasing the time of G-IFN exposure from 24 to 72 hr at 10 units/ml increased the level of phagocytic inhibition from 39 to 49%, respectively. The rate of microsphere uptake was also reduced in a dose-dependent fashion. Morphologic examination after G-IFN incubation showed that HTM cells became enlarged and flattened compared to the control. Actin cytoskeletal immunofluorescence staining showed that parallel actin beams of the control cells were changed to a radical, spokelike arrangement when incubated in G-IFN. CONCLUSIONS: G-IFN is a potent inhibitor of HTM cell phagocytosis in vitro. G-IFN's effect on the actin cytoskeleton suggests that G-IFN may be disturbing the cytoskeletal organization necessary for phagocytosis.

Actins↗
PubMed1992

Gonioscopic ab interno laser sclerostomy. A pilot study in glaucoma patients.

PURPOSE: The purpose of this study is to evaluate the safety and efficacy of gonioscopic ab interno laser sclerostomy (GLS) in patients with glaucoma. METHODS: The technique of GLS involves iontophoresis of methylene blue dye (1%) at the limbus to focally dye the sclera and to provide subsequent delivery of 10-microsecond pulsed laser energy to the dyed area through a goniolens. The laser emits at 660 nm, a wavelength that is maximally absorbed by the methylene blue dye. Patients were evaluated for fistula formation, intraocular pressure (IOP) reduction, and adverse sequelae. Thirty-eight treatments were performed in 35 eyes. RESULTS: Successful complete sclerostomies were achieved in 21 eyes (55%), which was associated with an acute mean reduction in IOP of 23 mmHg. Mean preoperative IOP for all patients was 35 mmHg, and 1 hour after treatment it was reduced to 18.5 mmHg. In 4 of the 38 treatments, there was no acute IOP reduction, and these eyes were judged as failures. The mean follow-up time was 8.2 months with a maximum follow-up of 15 months. By 9 months, 50% of patients had an IOP of 22 mmHg or lower. The number of antiglaucoma medications decreased from 3.1 to 1.7 for all eyes over the 15-month follow-up period. Hyphemas (13%) were the only major complication, and these resolved spontaneously. In only one case did the IOP increase after the procedure. CONCLUSION: The results of this trial indicate that GLS is technically feasible, and preliminary results of IOP control are promising.

Adult↗
PubMed1992

Contact transscleral Nd:YAG laser cyclophotocoagulation. Midterm results.

BACKGROUND: Early reports of both contact and noncontact transscleral Nd:YAG laser cyclophotocoagulation have been encouraging; however, recent evidence indicates a significant incidence of hypotony, visual loss, and phthisis with the noncontact technique with more than 6 months of follow-up. The authors sought to determine the intermediate term effects of contact transscleral Nd:YAG laser cyclophotocoagulation (CYC). METHODS: The authors followed 116 eyes of 114 patients for a minimum of 1 year after treatment of advanced glaucoma with CYC. RESULTS: The mean preoperative intraocular pressure (IOP) of 35.0 +/- 1.0 mmHg decreased to 18.6 +/- 1.1 mmHg (P less than 0.0001) during the average follow-up of 19.0 +/- 0.6 months (range, 12 to 36 months). Intraocular pressure control of 3 to 25 mmHg was achieved in 72%, 3 to 22 mmHg in 65%, and 3 to 19 mmHg in 56% of eyes. Retreatment was required in 31 of the 116 eyes (27%). Intraocular pressure decreased to less than 3 mmHg in 9 eyes and to 0 mmHg in 6 of these 9 eyes. Nineteen eyes, all with initial visual acuity of counting fingers or worse, progressed to no light perception; 17 of 36 eyes (47%) with visual acuity of 20/200 or better lost 2 or more Snellen lines. CONCLUSION: Midterm results of CYC continue to be encouraging but are tempered by a nearly 10% incidence of hypotony or phthisis and the progression of visual loss.

Adolescent↗
PubMed1992

The use of tissue plasminogen activator in experimental filtration surgery.

Tissue plasminogen activator (tPA), a clot-specific fibrinolytic agent, was used as an adjunct to filtration surgery in Dutch belted rabbits to determine its effects on the outcome of filtration surgery. Thirty-eight animals that underwent a standardized posterior-lip sclerectomy in both eyes were divided into five postoperative protocol groups. In masked fashion, experimental eyes received 25 micrograms of tPA in 100 microL of diluent. Fellow eyes received 100 microL of diluent and served as controls. Group 1 received daily subconjunctival tPA. Group 2 received intracameral, followed by daily subconjunctival, tPA. Groups 3, 4, and 5 received intracameral tPA on postoperative days 1 and 2;2 and 3; and 3, 4, and 5, respectively. Intraocular pressure (IOP), quality of bleb, number of days to bleb failure, and incidence of intraocular bleeding were determined in each group. No significant tPA effect was seen in groups 1 or 2. In groups 3, 4, and 5, the tPA-treated eyes demonstrated marked reduction of IOP and improvement in the quality of the blebs lasting between 6 to 24 hours.

Animals↗
PubMed1991

Internal and transconjunctival neodymium:YAG laser revision of late failing filters.

Seven cases of hypofunctioning trabeculectomies or full-thickness filters were treated using the Q-switched neodymium:YAG (Nd:YAG) laser delivered either transconjunctivally, gonioscopically, or by a combination approach. In four eyes, internal laser revision was attempted initially. Internal revision was successful in one case, where the sclerostomy had become occluded by a fibrous membrane. The Nd:YAG laser was then focused transconjunctivally onto the episcleral fibrous tissue within the bleb in the three eyes treated unsuccessfully by the internal approach and used as a primary treatment in three additional cases. Transconjunctival laser treatment was successful in producing an immediate and substantial decrease in intraocular pressure (IOP) (mean IOP reduction of 12 mmHg at 2 hours posttreatment) in all cases. In six of seven cases, there was a persistent reduction of intraocular pressure with an average of 5.7 months of follow-up. Transconjunctival Nd:YAG laser revision of hypofunctioning filters may be effective in restoring filtration in selected cases.

Aged↗
PubMed1991

Gamma-interferon effects on human fibroblasts from Tenon's capsule.

Gamma-interferon (G-IFN) exhibits antiproliferative effects, inhibits collagen synthesis by fibroblasts, and may help to regulate the turnover of fibrous tissue. Fibroblasts from Tenon's capsule are cellular components that contribute to unsuccessful glaucoma filtration surgery. Therefore, the authors studied the effects of G-IFN on growth, wound closure, collagen synthesis, and extracellular matrix in cultured human Tenon's capsule fibroblasts (HTCF). HTCF incubated with G-IFN at doses of 1 to 1000 U/ml showed cellular heterogeneity, with some cells showing morphologic changes characteristic of senescence, and a dose-dependent inhibition of wound closure. At 1000 U/ml, G-IFN reduced collagen synthesis by 57%, reduced immunofluorescent staining of collagen type I and fibronectin network, and altered the organization of actin microfilaments into large cable-like structures. Cell proliferation and viability were not affected at any concentration of G-IFN. These results suggest that G-IFN may be useful to modulate wound healing after filtration surgery.

Cell Division↗
PubMed1990

Laser sclerostomy by pulsed-dye laser and goniolens.

We describe an ab-interno laser sclerostomy procedure using the method termed dye-enhanced ablation with a slit-lamp delivery system and special goniolens such that only the laser light beam penetrates the anterior chamber. The procedure uses a microsecond-pulsed-dye laser emitting at 666 nm and iontophoresis of methylene blue dye (absorption of 668 nm) into the sclera at the limbus to enhance the absorption of the laser light. We compared the number of pulses needed to perforate excised human sclera at pulse durations of 1.5, 20, and 300 microseconds. Pulse durations of 1.5 and 20 microseconds required 20 pulses or fewer to perforate excised human sclera with pulse energies of 75 to 100 mJ. The ab-interno laser sclerostomy procedure was performed in 54 eyes of Dutch-belted rabbits with pulse durations of 1.5 or 20 microseconds and a 100- or 200-microns incident spot diameter delivered using a CGF goniolens. Full-thickness fistulas were successfully created at both pulse durations in approximately 80% of eyes treated. A range of three to 25 pulses was required to perforate sclera with slightly fewer pulses and lower pulse energies at 1.5 microseconds compared with 20 microseconds. There were no significant complications from the procedure. This technique could permit filtration surgery to be performed on an outpatient basis.

Animals↗
PubMed1990

Contact transscleral continuous wave neodymium:YAG laser cyclophotocoagulation.

Advanced glaucoma in 140 eyes of 136 patients was treated with contact transscleral continuous wave neodymium:YAG (Nd:YAG) laser cyclophotocoagulation (CYC) with a sapphire-tipped probe. The anterior edge of the probe was placed 0.5 to 1.5 mm posterior to the limbus, using 7 to 9 W of power for 0.7 seconds with 32 to 40 applications, sparing the 3 and 9 o'clock meridians. Patients were studied prospectively. The mean preoperative intraocular pressure (IOP) of 36.7 +/- 0.97 mmHg decreased to 21.2 +/- 0.99 mmHg (P = 0.004) after treatment (mean follow-up, 3.2 +/- 0.35 months) for a mean decrease in IOP of 15.5 +/- 1.21 mmHg and a mean percent decrease of 39%. Forty-one eyes were followed 6 or more months (mean, 6.7 +/- 0.25 months). The CYC reduced IOP to 25 mmHg or less in 71% of eyes, to 22 mmHg or less in 62% of eyes, and to 19 mmHg or less in 49% of eyes. Maximum lowering of IOP occurred 1 week to 1 month after treatment and remained at that level through 6 months of follow-up. Retreatment was required in 11% of patients; only one patient was retreated more than once. Four patients treated with 9 W of power developed IOPs below 5 mmHg; two of these patients had an IOP of 0 mmHg. Other complications of therapy were minimal, and patients had little pain. There was no significant change in visual acuity. Early results of this newly available therapy are encouraging.

Adolescent↗
PubMed1990

The dural shunt syndrome. I. Management of glaucoma.

The authors present four cases of the dural shunt syndrome in which shallowing of the anterior chamber or rubeosis developed. All patients were female, ranging in age from 66 to 79 years, exhibiting elevated intraocular pressure (IOP), decreased extraocular movements, injected tortuous episcleral vessels, and proptosis. The authors managed these four cases with laser iridotomy, gonioplasty, panretinal photocoagulation, or medical treatment. It is important to recognize associated findings in patients with shallow anterior chambers and elevated IOPs so that a diagnosis of a dural shunt is considered and appropriately treated. Theories on the mechanisms of increased IOP in the dural shunt syndrome and the management of various types of glaucoma in four different cases are reviewed.

Aged↗
PubMed1990

Single stage Molteno implant with combination internal occlusion and external ligature.

A variety of techniques have been devised to reduce postoperative hypotony following a single-stage Molteno implant procedure. Although they effectively reduce hypotony, these techniques may result in a prolonged increase of intraocular pressure (IOP). I present a technique, consisting of placement of a 5-0 nylon internal occlusion suture combined with an external polyglactin (Vicryl) ligature around the Molteno tube, to prevent both hypotony and elevated IOP after implantation.

Humans↗