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Gian Marco Tosi

Publications and source records attributed to Gian Marco Tosi.

18 recordsLinked to original sources
PubMed2006

Measurement of the actual dose of triamcinolone acetonide delivered by common techniques of intravitreal injection.

PURPOSE: To measure the actual dose of triamcinolone acetonide (TA) delivered during intravitreal injection performed by several common techniques. DESIGN: Experimental study. METHODS: A 0.1-ml, 40-mg vial of TA (Kenalog-40; Bristol-Myers-Squibb, Peapack, New Jersey, USA) was prepared according to one of four protocols and the mass determined after drying overnight on waxed paper. In group 1, a 0.1-ml aliquot of TA was dispensed with a 30-gauge needle after shaking the vial 10 or 30 times. Group 2 used a 27-gauge needle. In group 3, the supernatant was removed from the crystals. Group 4 passed the suspension through a 0.2-microm micropore filter and rinsed the crystals with saline. RESULTS: There was no statistically significant difference between 30- or 27-gauge needles (P = 0.83, t test) or between shaking the vial 10 or 30 times before withdrawing the drug (P = 0.99). A statistically significant difference (t test, P = 0.001) was found between TA delivered from the initial 60% of each syringe (mean +/- SD, 2.7 +/- 1.0 mg) to that drawn from the last 40% of each syringe (7.8 +/- 3.6 mg). Group 3 had a mean weight of 32.1 +/- 7.0 mg and group 4, 10.6 +/- 2.1 mg. CONCLUSIONS: Efforts to achieve a 4.0-mg dose of TA, regardless of method used, are variable and inconsistent. Injecting through a small-gauge needle appears to concentrate the remaining suspension. Techniques to concentrate TA or remove aqueous preservatives by filtering effectively increase the concentration, but these results are variable.

Filtration↗
PubMed2006

In vivo confocal microscopy in recurrent granular dystrophy in corneal graft after penetrating keratoplasty.

Two case reports of recurrent granular dystrophy in corneal grafts after penetrating keratoplasty are presented. Slit-lamp examination and confocal microscopy (HRT II) were performed in two patients with recurrent granular dystrophy. All confocal microscopic findings of granular dystrophy were evaluated in the graft. Dystrophic lesions of the donor cornea presented the same confocal microscopic aspects in both eyes, and were similar to granular dystrophy lesions. Confocal microscopy is an imaging method that may provide new information on corneal microanatomy in dystrophies. It may be particularly useful in improving the early diagnosis of dystrophic lesions in corneal grafts.

Cornea↗
PubMed2005

Genetic and epigenetic alterations of RB2/p130 tumor suppressor gene in human sporadic retinoblastoma: implications for pathogenesis and therapeutic approach.

Human retinoblastoma occurs in two forms (familial and sporadic) both due to biallelic mutation of the RB1/p105 gene even if its loss is insufficient for malignancy. We have recently reported that loss of expression of the retinoblastoma-related protein pRb2/p130 correlates with low apoptotic index, suggesting that RB2/p130 gene could be involved in retinoblastoma. Mutational analysis of RB2/p130 in primary tumors showed a tight correlation between Exon 1 mutations and pRb2/p130 expression level in sporadic retinoblastoma. These mutations are located within a CpG-enriched region prone to de novo methylation. Analysis of RB2/p130 methylation status revealed that epigenetic events, most probably consequent to the Exon 1 mutations, determined the observed phenotype. Treatment of Weri-Rb1 cell line by 5-Aza-dC induced an increase in expression level of pRb2/p130, E2F1, p73 and p53. Overall, our results highlight a crucial role of epigenetic events in sporadic retinoblastoma, which opens a perspective for new therapeutic approaches.

Azacitidine↗
PubMed2005

Amniotic membrane graft: histopathological findings in five cases.

Amniotic membrane transplantation (AMT) is an effective treatment for ocular surface reconstruction; however, the mechanisms through which amniotic membrane (AM) exerts its effects as well as its fate after transplantation have not been entirely elucidated and have been investigated only in part. We evaluate the integration of AM in the host cornea in five patients who underwent AMT as the result of Bowen's disease, band keratopathy, radio- or cryotherapy-induced keratopathy, chemical burn or post-herpetic deep corneal ulcer with descemetocele. Due to persistent opacification in four cases and a progressing tumor in one case, penetrating keratoplasty (PK) and enucleation were performed as early as 2 months and up to 20 months after AMT. The corneas were analyzed histopathologically. To evaluate AM remnants, corneas were stained with periodic acid Schiff's reaction (PAS), Alcian blue, and Gomory and Masson trichrome; immunostaining including collagens III and IV antibodies was also performed. None of the corneas showed remnants of AM. In all cases, we observed discontinuity of Bowman's membrane. In three cases, the corneal epithelium was completely restored, ranging from three to six cell layers. In the other two cases, we detected an intense inflammatory reaction with rich neovascularization; the epithelial surface of the central cornea was completely restored, while at the periphery of the cornea goblet mucus-producing cells were present. Although clinically useful in all cases, restoration of a stable corneal epithelium through AMT is limited by the extent and severity of limbal stem cell deficiency (LSCD). The lack of histologically documented AM remnants in our cases seems to explain the efficacy of AMT more through its biological properties than through its mechanical properties.

Aged↗
PubMed2005

Amniotic membrane transplantation in ocular surface disorders.

Chronic ocular surface disorders, which can result in severe functional impairment, have been viewed for decades as untreatable diseases. In 1995, the reintroduction of amniotic membrane transplantation (AMT), either alone or associated with limbal stem cell transplantation, has offered new hope of using tissue and cell therapy strategies to repair ocular surface disorders. Amniotic membrane (AM) has been found to exert its effects by acting as a substrate for the growth of ocular surface epithelia, by suppressing inflammation and scarring and by serving as an anti-microbial barrier. Moreover, AM has recently been used as a substrate for ex vivo expansion of corneal epithelial cells for ocular surface reconstruction. Notwithstanding the substantial agreement among Authors regarding its clinical efficacy, there are still many uncertainties regarding the fate of grafted AM and consequently the mechanisms through which it exerts its long-term effects. Further studies including controlled clinical trials with numerous cases are required to understand which ocular surface conditions are certain to benefit from AM transplantation and how its mechanical properties interact with the mediators produced to favor ocular surface reconstruction.

Amnion↗
PubMed2005

Management of severe hypotony with intravitreal injection of viscoelastic.

PURPOSE: To investigate the effect of an intravitreal injection of sodium hyaluronate 1.4% and 2.3% in the treatment of hypotony. DESIGN: Interventional case series. METHODS: Intravitreal injection of sodium hyaluronate 1.4% was performed to treat persistent hypotony in three eyes after the successful repair of retinal detachment and in one eye with uveitis. Injection of sodium hyaluronate 2.3% was performed in one eye after the successful repair of retinal detachment with removal of silicone oil. RESULTS: At the last follow-up examination (2-16 months), intraocular pressure increased to at least 5 mm Hg (5-14 mm Hg) in all eyes that had been injected with sodium hyaluronate. Intraocular pressure increased to 38 mm Hg in the eye that had been injected with sodium hyaluronate 2.3% on postoperative day 1 and was 10 mm Hg at three months. Vision improved in all patients. CONCLUSION: Intraocular injection of sodium hyaluronate 1.4 and 2.3% appears to be efficacious in reversing hypotony in some eyes. Functional and structural findings can also improve.

Aged↗
PubMed2005

Glare disability and spherical aberration with five foldable intraocular lenses: a prospective randomized study.

PURPOSE: To compare differences in subjective glare and spherical aberration between five foldable intraocular lenses (IOLs) made of different materials and to different designs. METHODS: This prospective study comprised 175 cataract patients who underwent phacoemulsification and were randomized to receive one of five types of foldable IOL (AcrySof MA30BA, Alcon; Sensar AR40, AMO; AcrySof SA30AL, Alcon; Sensar AR40e, AMO, and Tecnis Z9000, Pharmacia & Upjohn). All patients received a questionnaire investigating the incidence of subjective photic phenomena. Two months postoperatively, we collected data regarding subjective glare and evaluated pupil size, visual acuity and wavefront aberration of the cornea and eye. RESULTS: With regard to difficulty in performing ordinary activities under different light conditions and light and dark adaptation, the difference between the groups was not significant (p > 0.05, chi-squared test). With respect to difficulty in driving at night, the MA30BA group had a significant higher incidence of photic phenomena than the SA30AL, AR40e and Z9000 groups (p < 0.05, chi-squared test). Wavefront measurements revealed a significant difference between the Z9000, AR40e and SA30AL groups, which showed the lowest values, and the MA30BA group, which showed the highest value (p < 0.05, anova with Tamhane posthoc test). CONCLUSIONS: New generation IOLs such as the Pharmacia Z9000, AMO AR40e and AcrySof SA30AL have a lower incidence of glare and spherical aberrations; however, their impact on future IOL design should be conditioned by further data, especially regarding posterior capsule opacification.

Acrylic Resins↗
PubMed2004

Late corneal scarring after retinal detachment surgery 42 months after photorefractive keratectomy.

A 42-year-old man had uneventful bilateral nonsimultaneous photorefractive keratectomy (PRK) for severe myopia. Thirty-nine months after the procedure, the patient presented with a retinal detachment (RD) in the right eye. Cerclage, vitrectomy, endolaser, and intravitreal silicone oil tamponade were performed, and the RD was successfully repaired. Three months after vitrectomy and 42 months after PRK, the patient complained of visual impairment in the right eye and photophobia. On slitlamp examination, marked reticular scarring of the central anterior cornea was observed. The occurrence of late-onset corneal haze highlights the need for special attention to patients who have vitrectomy after PRK.

Adult↗
PubMed2004

Digital surface microscopy analysis of conjunctival pigmented lesions: a preliminary study.

The objective of this study was to investigate whether digital surface microscopy (DSM) could be used for the follow-up and comparison of malignant and benign conjunctival pigmented lesions (CPLs). Thirty-nine CPLs [16 de novo malignant melanomas (MMs), one MM arising from primary acquired melanosis (PAM), six PAMs and 16 naevi] were digitally analysed and biopsied. All of the PAMs and 10 naevi, which had not been surgically excised, were followed up using DSM. Thirty parameters were evaluated grouped into four categories: geometry, colour, texture and islands of colour. None of the CPLs that were followed up, which comprised 10 naevocytic naevi and seven PAMs, showed any morphological change at DSM analysis, except for one PAM which developed an MM 1 year later. Of the geometric variables examined, the area, maximum diameter and minimum diameter showed significantly higher values in MMs compared with benign CPLs. With regard to the colour of CPLs, MMs were significantly darker and bluer than naevi. In the texture group, contrast was significantly higher in MMs. In the islands-of-colour group, the imbalance of blue-grey regions and the presence of dark areas were significantly higher in MMs. DSM greatly simplified the follow-up of CPLs, such as PAMs with atypia, by providing satisfactory quality images with high reproducibility; this technique is also easy to use and well accepted by patients. Moreover, this preliminary study allowed us to determine which objective variables could be important for distinguishing between benign CPLs and conjunctival MMs.

Adolescent↗
PubMed2003

Phacoemulsification without intraocular lens implantation in patients with high myopia: long-term results.

PURPOSE: To estimate the cumulative incidence of postoperative retinal detachment (RD), rhegmatogenous retinal lesions requiring argon laser treatments, anterior (ACO) and posterior (PCO) capsule opacification, and neodymium:YAG (Nd:YAG) laser capsulotomy in patients with high myopia who had phacoemulsification without intraocular lens (IOL) implantation. SETTING: Department of Ophthalmology and Neurosurgery, University of Siena, Siena, Italy. METHODS: Seventy-three eyes of 57 patients with high myopia who had phacoemulsification without IOL implantation from 1993 to 1996 were retrospectively reviewed. The mean postoperative follow-up was 62.3 months and the mean axial length, 30.22 mm (range 29.10 to 33.70 mm). The incidence of RD and preoperative and postoperative prophylactic argon laser photocoagulation for rhegmatogenous retinal lesions were assessed. Between 1997 and 2000, ACO was evaluated subjectively and PCO was evaluated using the EPCO photographic image-analysis system. The incidence of Nd:YAG laser capsulotomy was noted. RESULTS: Argon laser photocoagulation was performed in 8 eyes (10.9%) preoperatively and 3 eyes (4.1%) postoperatively. One RD (1.3%) was observed 26 months after surgery; no preoperative or postoperative prophylactic argon laser photocoagulation or Nd:YAG laser capsulotomy was performed in this eye. At 1 year, 49 eyes (67.1%) had mild ACO and 24 (32.8%) had anterior capsule fibrosis. The data did not change during subsequent follow-up visits. At 6 years, the mean PCO grade was 1.109 (range 0.972 to 2.931); an Nd:YAG laser capsulotomy was performed in 12 eyes (16.4%). CONCLUSIONS: Compared with other studies that evaluated the outcomes of highly myopic patients who had cataract surgery with posterior chamber IOL implantation, our patients, who did not have IOL implantation, had a lower incidence of postoperative rhegmatogenous retinal lesions requiring argon laser treatments and a similar incidence of postoperative RD and visually significant PCO.

Aged↗
PubMed2002

Orbital solitary fibrous tumor with aggressive behaviorThree cases and review of the literature.

BACKGROUND: Solitary fibrous tumor (SFT) is a rare spindle cell tumor that arises most often in the visceral pleura; however, a review of the literature shows at least 31 cases occurring in the orbit. METHODS: A retrospective case series of three patients with orbital SFT: a 50-year-old man, observed in 1997, with an angioma-like lesion in the upper half of the orbit causing osteolysis of the orbital roof; a 24-year-old man, observed in 1992, with a superotemporal mass in the right orbit occupying the lacrimal gland region, firstly diagnosed as schwannoma, recurring 4 years after dacryoadenectomy; a 70-year-old man, with a retrobulbar mass diagnosed on a biopsy as hemangiopericytoma, recurring and infiltrating the orbital roof 4 years after surgery. RESULTS: A review of the literature and presentation of three cases of SFT which showed infiltration of the orbital roof and/or recurrence. CONCLUSIONS: Our cases provide evidence of how orbital SFT can behave aggressively and mimic other orbital tumors, thus making mandatory the consideration of this relatively new entity in common clinical practice as well as careful follow-up. Their aggressive growth is unusual, described in only 6 of the 31 cases so far reported in the literature. Immunohistochemistry is of importance for the diagnosis, since CD34 immunoreactivity is peculiar to SFT.

Adult↗
PubMed2002

CD-34 stromal expression pattern in normal and altered human corneas.

OBJECTIVE: To test CD-34 immunoreactivity in stromal cornea cells in normal and pathologic samples obtained from penetrating keratoplasty. DESIGN: Prospective, consecutive histopathologic human tissue study. PARTICIPANTS AND CONTROLS: One hundred two cornea buttons from patients with different diseases, submitted for cornea transplant, were examined. Controls were expired corneas from healthy donor patients who died (n = 4), and globes enucleated for primitive intraocular neoplasias, that is, retinoblastomas (n = 8), and malignant choroidal melanomas (n = 2). METHODS: The expression of CD-34 in stromal cornea cells was examined by immunohistochemistry analysis. Other immunohistochemical stains included an endothelial cell marker (CD-31), common leukocyte antigen, and alpha-smooth muscle actin. MAIN OUTCOME MEASURES: Different diseases that may cause blindness and require penetrating keratoplasty have been tested for CD-34 immunoreactivity. RESULTS: In control corneas, keratocytes present strong and consistent CD-34 immunoreactivity. Diseases leading to the loss of transparency and penetrating keratoplasty, such as keratoconus, herpes keratitis, trauma, and heredofamilial dystrophies, are associated with focal or diffuse loss of CD-34 expression, whereas pseudophakic bullous keratopathy and Fuchs' endothelial dystrophy show normal CD-34 immunoreactivity in most cases and patchy unstained stromal areas in a few cases. CONCLUSIONS: Scar tissue formation in the cornea, as in herpes keratitis and trauma, is always associated with loss of CD-34 immunoreactivity, which may otherwise be a primary event in keratoconus and heredofamilial dystrophies. Both in the pseudophakic bullous keratopathy and Fuchs' endothelial dystrophy, CD-34 immunoreactivity may be normal or lost, hence these two diseases may be considered as one and part of the same group with regard to CD-34 expression, as revealed by immunohistochemistry analysis.

Actins↗
PubMed2002

Preliminary results of cataract extraction with implantation of a single-piece AcrySof intraocular lens.

PURPOSE: To evaluate the intraoperative and postoperative performance of the single-piece AcrySof SA30AL intraocular lens (IOL) in a series of patients after cataract surgery and IOL implantation. SETTING: Department of Ophthalmology and Neurosurgery, University of Siena, Siena, Italy. METHODS: In this prospective study, 20 patients who had phacoemulsification and implantation of a single-piece AcrySof SA30AL lens from March to April 2000 were evaluated. Assessed were control of IOL folding, ease of IOL implantation, IOL centration, intraoperative and postoperative complications, visual acuity, and anterior (ACO) and posterior (PCO) capsule opacification. RESULTS: In all cases, the IOL was easily folded, inserted, and unfolded. It remained well centered in the capsular bag, and there were no intraoperative or postoperative complications. The best corrected visual acuity after surgery was 20/40 or better in all patients. No eye developed ACO or phimosis. One eye had a well-demarcated, oval area of lens epithelial cell proliferation on the posterior capsule that did not impair visual acuity. CONCLUSIONS: Initial results indicate that the single-piece AcrySof SA30AL IOL has good biocompatibility, haptic flexibility and resistance, and stability in the capsular bag. The incidence of PCO in 1 eye could have been the result of several factors and requires further evaluation. An area of future study is the wide haptic of the lens, which may create a path for cells to proliferate as they travel from the equatorial capsule.

Acrylic Resins↗
PubMed2002

Comparison of AcrySof MA30BA and Sensar AR40 acrylic intraocular lenses.

PURPOSE: To compare differences in anterior (ACO) and posterior (PCO) capsule opacification and subjective glare between 2 acrylic intraocular lenses (IOLs): AcrySof MA30BA (Alcon) and Sensar AR40 (Allergan). SETTING: Department of Ophthalmology and Neurosurgery, University of Siena, Siena, Italy. METHODS: This retrospective study comprised 100 cataract patients who had phacoemulsification and IOL implantation. Fifty eyes of 50 patients received an MA30BA and 50 eyes of 50 patients, an AR40. The mean postoperative follow-up was 25 months (range 20 to 31 months) and 22 months (range 19 to 29 months), respectively. Examiners subjectively evaluated ACO, and a photographic image-analysis system was used to assess PCO. All patients received a questionnaire to evaluate the incidence of subjective photic phenomena. RESULTS: In the MA30BA group, 60% had no ACO, 19% had mild ACO, and 21% had anterior capsule fibrosis. In the AR40 group, 55% had no ACO, 27% had mild ACO, and 18% had anterior capsule fibrosis. In the MA30BA group, the mean PCO score measured by image-analysis was 0.043 (range 0.000 to 0.084) at 1 year and 0.125 (range 0.000 to 0.197) at 2 years and in the AR40 group, 0.071 (range 0.000 to 0.157) and 0.230 (range 0.091 to 0.628), respectively. Although the ACO percentages and the PCO scores at 1 year were not statistically different between the 2 groups (P >.05), the MA30BA group had statistically less PCO at 2 years (P <.05). In the MA30BA group, 36 patients had trouble reading in a dim environment, 25 had difficulty driving at night, 25 were mildly bothered by the lights of other vehicles, and 17 saw halos when looking at the lights of other vehicles and 17, when looking at lights at night. In the AR40 group, 7 patients had trouble reading in a dim environment and 11 had difficulty driving at night. At 6 months, the AR40 group had a statistically significantly lower incidence of photic phenomena than the MA30BA group (P <.05). In the MA30BA group 1 year after surgery, 13 patients had trouble reading in a dim environment and 12 had difficulty driving at night. In the AR40 group, 5 patients had trouble reading in a dim environment and 8 had difficulty driving at night. One year after surgery, the difference between the 2 groups in photic phenomena was not statistically significant (P >.05). CONCLUSIONS: The findings indicate that the AcrySof MA30BA has a lower incidence of PCO than the Sensar AR40. The AR40 IOL induced less glare; however, the glare phenomena did not disturb those with an MA30BA lens and the symptoms decreased by 1 year after surgery. These results suggest that both optic design and haptic material influence postoperative clinical results.

Acrylic Resins↗
PubMed2002

Expression of RB2/p130 tumor-suppressor gene in AIDS-related non-Hodgkin's lymphomas: implications for disease pathogenesis.

In this study we examined 21 cases of AIDS-related lymphomas for genomic organization and expression of RB2/p130 oncosuppressor gene and compared the results with the proliferative features of these neoplasms. We found no mutations in the RB2/p130 gene and unusually high percentages of cells expressing nuclear pRb2/p130 in tumors with a high proliferative activity, such as AIDS-related lymphomas. These findings might suggest that a molecular mechanism usually observed in viral-linked oncogenesis could be involved. We performed in vitro and in vivo binding assays to investigate whether the human immunodeficiency virus (HIV) gene product Tat and Rb2/p130 could interact. The results of these assays revealed that the HIV-1 Tat protein binds specifically to pRb2/p130. This may result in the inactivation of its oncosuppressive properties and the induction of genes needed to proceed through the cell cycle including p107, cyclin A, and cyclin B. Using single-cell polymerase chain reaction (PCR) assay, we found HIV-1 DNA in the neoplastic cells of only 2 of the 21 cases examined, whereas PCR on whole tissue revealed HIV-1 DNA in all of the cases. Furthermore, a diffuse and nuclear stain was observed in tissue sections with anti-Tat monoclonal antibody. These findings are in accordance with the notion that soluble Tat protein could function as a biologically active extracellular protein released by infected cells and taken up readily by uninfected B cells. In conclusion, our results seem to suggest that pRb2/p130 oncosuppressor protein may be a target in the interaction between the HIV-1 gene products and host proteins.

Adult↗
PubMed2002

Missing expression of pRb2/p130 in human retinoblastomas is associated with reduced apoptosis and lesser differentiation.

PURPOSE: Although the retinoblastoma gene (RB/p105) has been intensely investigated as a prototype suppressor gene in humans, mutational data on the Rb family member pRb2/p130 (p130) has only recently been reported. A protective role against apoptosis has been suggested for pRb/p105, both in vitro and in vivo. However, only limited information is available on the role of pRb2/p130 in controlling apoptosis. The purpose of this study was to determine the extent of a role of this gene in the neoplasms that give the Rb family its name. METHODS: Forty-two human retinoblastomas were retrospectively examined by immunohistochemical labeling of the Rb-related proteins and the results compared with cellular kinetic characteristics: the apoptotic index (AI) and the mitotic index (MI). RESULTS: The retinoblastomas that did not express p130 showed a significantly lower AI than those that expressed p130. This result was also supported by flow cytometry on a human Saos-2 cell line that was transiently transfected with RB2/p130. The p130(-) tumors displayed a lesser degree of differentiation than the p130(+) ones. CONCLUSIONS: These observations give evidence that expression of p130 is inversely correlated with higher rates of apoptosis in human retinoblastomas and give an additional example of this regulator's role in cellular differentiation.

Apoptosis↗