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Biomedical subjects

A Sebastiani

Publications and source records attributed to A Sebastiani.

At least 37 records · Page 2Linked to original sources
PubMed1997

Non-contact tonometry in patients that underwent photorefractive keratectomy.

To determine the accuracy of non-contact tonometry in patients with corneas thinned by photorefractive keratectomy, the authors measured the intraocular pressure with a non-contact tonometer and the corneal thickness with an ultrasonic pachymeter in 47 patients before and 9 months after photorefractive keratectomy. The patients were divided into three groups according to the degree of treatment: group I between 1 and 5 diopters (14 eyes), group II between 6 and 10 diopters (18 eyes), group III between 11 and 15 diopters (15 eyes). In the first group of patients mean intraocular pressure was 16.1 (+/-3.85) mm Hg before surgery, and 13.2 (+/-3.14) mm Hg after surgery with a significant difference (p = 0.0027). In the second group of patients mean intraocular pressure was 16.0 (+/-4.13) mm Hg before surgery and 13.0 (+/-3.0) mm Hg after surgery with a significant difference (p = 0.0045). In the third group of patients mean intraocular pressure was 17.7 (+/-3.8) mm Hg before surgery and 12.4 (+/-2.6) mm Hg after surgery, with a significant difference (p = 0.0005). In conclusion, according to our results, non-contact tonometry needs a correcting factor for measuring the intraocular pressure in patients that underwent photorefractive keratectomy, related to the degree of refractive treatment.

Adult↗
PubMed1997

Endothelial cells evaluation two years after photorefractive keratectomy.

To evaluate long-term corneal endothelium damages after myopic photorefractive keratectomy (PRK) a morphometric analysis of corneal endothelial cells was performed in 41 patients before and at least 24 months after photorefractive keratectomy. These patients underwent a treatment ranging from -2.5 to -14 dpt with a mean of 8.9 +/- 2.8 dpt at the corneal apex, with an estimated corneal thinning ranging from 23 to 123 microns with a mean of 78 +/- 24.4 microns. Our results showed that the density of endothelial cells ranged from 2,334 to 3,554/mm2 with a mean of 2,819 +/- 351/mm2 before surgery, and from 2,051 to 3,461/mm2 with a mean of 2,774 +/- 330/mm2 after surgery without any significant changes (p = 0.16). The polymorphic index ranged from 58 to 84 with a mean of 77 +/- 5.7 before PRK and from 57 to 89 with mean of 77.7 +/- 7.2 after treatment without any significant changes (p = 0.61). In conclusion, we can state that there is no long-term corneal endothelial damage after PRK even in highly myopic eyes.

Adolescent↗
PubMed1996

Refractive outcome and corneal topographic studies after photorefractive keratectomy with different-sized ablation zones.

BACKGROUND: Discrepancies may still occur between planned and actual refractive correction in eyes undergoing photorefractive keratectomy (PRK). The authors have evaluated the use of an enlarged ablation zone. METHOD: A computerized corneal analysis system has been used to compare the changes of the anterior surface of the cornea and the refractive changes before and 1, 6, and 12 months after PRK in 113 patients (119 eyes) treated with an excimer laser. The patients were divided into two groups: those treated with a mask with a 5-mm window (59 eyes), and those with a new mask with different window openings according to the degree of refraction at the corneal apex, starting from 5 mm in diameter for treatments less than 6.5 diopters (D) and from 7 mm in diameter for higher treatments (60 eyes). In the first group, treatment ranged from -2.5 to -16 D (mean +/- standard deviation. -8.5 +/- 3.24 D); in the second group, it ranged from -1 to -14 D (-7.8 +/- 3.06 D). Treatments were evaluated with a chi-square test. RESULTS: In the first group of eyes, 46% were within +/-1 D at 1 month, 37% at 6 months, and 39% at 12 months. In the second group of eyes, 73% were within +/-1 D at 1 month, 60% at 6 months, and 58% at 12 months. The comparison between these data and corneal topographic changes shows that both are more stable and predictable with the new mask compared with the 5-mm mask (P = 0.002, 0.02, 0.04, at 1, 6, and 12 months, respectively). CONCLUSIONS: The use of larger ablation zones improves the predictability and stability of refractive changes.

Adult↗
PubMed1995

Effects on the corneal endothelium six months following photorefractive keratectomy.

Photorefractive keratectomy (PRK) with a 193-nm excimer laser has been shown not to destroy endothelial cells in vivo. However, this laser could damage endothelial cell metabolism, and result in damage over a longer term. In this paper, a comparison between the number and shape of corneal endothelial cells has been performed in 25 patients before and 6 months after PRK. These patients underwent treatment with myopic correction ranging from 2.5 to 17 dpt and with an estimated corneal thinning ranging from 25 to 170 microns. No significant changes in the number (p = 0.167) and shape (p = 0.075) of endothelial cells have been found. These results show that there are no long-term damages after PRK even in severely myopic eyes.

Adult↗
PubMed1994

ArF 193 nm excimer laser corneal surgery as a possible risk factor in cataractogenesis.

It was evaluated whether ArF 193 nm excimer laser corneal surgery represents a risk factor in cataractogenesis. For this purpose, 20 male albino rabbits underwent a photorefractive keratectomy and biochemical analyses on aqueous humour (hydrogen peroxide, ascorbic acid, and reduced and oxidized glutathione) and on lens (malondialdehyde, reduced and oxidized glutathione) were performed. In the aqueous humour of all treated animals a significant increase in hydrogen peroxide and in oxidized glutathione and a concomitant decrease in ascorbic acid and reduced glutathione concentration were observed. Moreover, all these variations were significantly correlated with the cumulative UV dose used. In the lens, after excimer laser corneal surgery, there was a dramatic loss of reduced glutathione and a parallel increase in oxidized glutathione levels. Malondialdehyde concentration was also increased, but only at the highest UV exposure. Moreover, all these variations were significantly correlated with the cumulative UV dose used. These findings demonstrate that the exposure of aqueous humour and lens to the secondary radiation generated after ArF 193 nm excimer laser corneal photoablative keratectomy induces biochemical modifications which are known to be markers of cataractogenesis.

Animals↗
PubMed1994

Local specific immunotherapy in allergic conjunctivitis.

We evaluated the effect of local specific immunotherapy in 40 patients suffering from seasonal allergic conjunctivitis. Twenty patients received saline solution in both eyes; and 20 others received local specific immunotherapy in both eyes. Sodium cromoglycate drops were instilled in both eyes in all patients. Subjective and objective symptoms, and cytological findings had significantly improved after 1 year in the group treated with local specific immunotherapy plus sodium cromoglycate compared to the group treated with sodium cromoglycate and saline solution.

Adolescent↗
PubMed1994

Phototherapeutic keratectomy in the treatment of Avellino dystrophy.

Avellino corneal dystrophy has rarely been reported in literature. It consists of a combination of granular and lattice dystrophy. Patients may complain of glare and decreased night vision with or without decreased visual acuity, depending on the degree of corneal involvement. Current treatment for this dystrophy includes bandage contact lenses for the erosions or corneal transplant in the case of decreased visual acuity. We describe the first patient with Avellino corneal dystrophy to have been treated with phototherapeutic keratectomy.

Aged↗
PubMed1994

Direct immunofluorescence and scraping conjunctival cytology in the study of 912 patients affected by microfollicular conjunctivitis.

912 patients affected by microfollicular conjunctivitis were submitted to a scraping conjunctival cytology before taking specimens for direct immunofluorescence. 264 patients proved to be positive to the direct immunofluorescence test for Chlamydia trachomatis (CT). In all cases the infection turned out to be bilateral with different degrees of positivity between one eye and the other. In 43 patients out of the 264 positive ones, the cytological examination showed the presence of eosinophils in both eyes. The presence of eosinophils poses the problem of a certain allergizing power of Chlamydia and of the possibility that the CT infection might easily develop in subjects with a preexistent allergic conjunctivitis.

Adolescent↗
PubMed1994

Fungal keratitis due to Scopulariopsis brevicaulis in an eye previously suffering from herpetic keratitis.

In the case reported, herpes virus I after having caused relapsing keratitis in an eye promoted the formation of a severe corneal ulcer caused by Scopulariopsis brevicaulis, a saprophytic mycete found in soil, which only once has been described as the cause of keratitis in man. Scopulariopsis was identified microscopically after culturing the conjunctival secretion on Sabouraud dextrose agar medium, while DNA probe tests confirmed the absence of herpes virus I. Topical and oral administration of miconazole and scraping of the corneal infiltrate dispersed the infection. Subsequently local steroids were given to reduce the neovascularization, and a therapeutic contact lens was applied because of intercurrent corneal thinning. Three months after beginning antifungal therapy, the visual acuity had increased from 1/120 to 1/10. The case described confirms that S. brevicaulis can cause opportunist infections in a cornea previously damaged by a different agent.

Conjunctiva↗
PubMed1993

Phenotypic variation in combined granular-lattice (Avellino) corneal dystrophy.

OBJECTIVE: To describe the phenotypic variation exhibited by members of families with combined granular-lattice (Avellino) corneal dystrophy. SETTING: We examined 40 patients (age range, 12 to 85 years) from six unrelated families with Avellino corneal dystrophy. This included the first individuals to ever be examined near the presumed site of origin in Italy. In addition, one family was the first to trace its origins to Germany rather than to Italy. We studied the phenotypic expression of the disease in the cornea, visual acuities, subjective complaints, complications, treatment, and histologic condition of these individuals. RESULTS: The granular stromal lesions reach their mature quantity and size early in life, and appear as either gray and crumb-shaped deposits or superficial with an annular and planar distribution. The lattice component appears gradually, beginning and maturing later in life. The phenotypic variation within families was found to be substantial. Widely variable proportions of lattice and granular changes were found within single sibships. Visual acuities ranged from 20/20 to 20/400. Recurrent corneal erosions were present but infrequent. Subjective complaints included glare and decreased night vision. Penetrating keratoplasty was required in one individual to restore vision. Histopathologic examination revealed typical amyloid and granular deposits. Granular deposits were found replacing Bowman's membrane and extending to the corneal surface. These deposits probably represent the cause of recurrent erosions. CONCLUSIONS: Combined granular and lattice corneal dystrophy may present with substantial phenotypic variation. The disease can be found in individuals who trace their ancestry to both Italy and Germany, a wider geographic distribution than previously proposed.

Adolescent↗
PubMed1993

Hepatitis C virus infection in chronic liver disease in Somalia.

To assess the role of hepatitis C virus (HCV) in liver disease in Somalia, antibody to HCV (anti-HCV) was studied by enzyme-linked immunosorbent assay (ELISA) and recombinant immunoblot assay (RIBA) in 110 patients with chronic liver diseases, in 309 healthy adults, in 179 institutionalized subjects with a high prevalence of intestinal parasites and Schistosoma haematobium, and in 287 children with diseases other than hepatitis. According to the RIBA test, anti-HCV was present in three healthy adults (0.97%), in four institutionalized individuals (2.2%), but in none of the children. The prevalence of anti-HCV was 4.8% in patients with hepatitis B surface antigen (HBsAg)-positive chronic liver diseases and 20.6% in patients with HBsAg-negative chronic liver diseases. Thus, HCV infection appears to play a minor role in HBsAg-positive liver disease in Somalia but may be an important factor in HBsAg-negative chronic liver disease. The low anti-HCV prevalence in individuals with no hepatic disorders is consistent with the fact that HCV does not spread by nonpercutaneous transfer. We found also a large proportion of both patients with hepatic disease and institutionalized individuals who tested positive by ELISA but not confirmed by RIBA. However, the likelihood of a true positive result increases proportionally with the ELISA value; thus, in most cases a low ELISA value probably represents a false-positive reaction, while a high ELISA value probably represents a true positive reaction.

Adult↗
PubMed1991

The serological diagnosis of human hydatid disease by time-resolved fluoroimmunoassay.

The use of a new immunoassay, time-resolved fluoroimmunoassay (TR-FIA), in the diagnosis of human hydatid disease has been evaluated. This technique, which is based on the labelling of antibodies with europium (Eu), was compared with a well-established method, the enzyme linked immunosorbent assay (ELISA). Of 102 patients with hydatid disease, 97 (95.1%) were positive according to TR-FIA and 83 (81.4%) according to ELISA. The rate of non-specificity for other parasitic infections (n = 206) was 8.7% for TR-FIA and 17.5% for ELISA. It is concluded that TR-FIA is more sensitive and more specific than ELISA in the diagnosis of human hydatid disease.

Animals↗
PubMed1990

Experimental keratitis in rabbits by human HSV-1 variants: prevention and treatment.

The efficacy of different therapies and vaccine preparations was assessed for treating or preventing herpetic ocular keratitis induced by experimental inoculation in rabbits with two HSV-1 variants that display different pathogenetic potential. Early administration of acyclovir (ACV) promoted fast healing and prevented neurologic involvements: alpha-interferon (alpha-IFN) was less efficient than ACV; combined therapy with both drugs increased the antiviral effects. In an attempt to prevent the disease, rabbits were vaccinated with a slightly pathogenic HSV-1 variant or with a secreted form of an engineered HSV-1 glycoprotein gB (gB-1s) and were subsequently challenged with a highly pathogenic HSV-1 variant. Immunization of rabbits with gB-1s was much more efficient than immunization with live virus in reducing the severity of herpetic keratitis and in preventing CNS disease.

Acyclovir↗