PubMed Health⌕ Search

Biomedical subjects

R Frezzotti

Publications and source records attributed to R Frezzotti.

51 records · Page 3Linked to original sources
PubMedDate not supplied

The polymerase chain reaction (PCR) in the routine genetic characterization of retinoblastoma: a tool for the clinical laboratory.

The Polymerase Chain Reaction (PCR) is a highly innovative technique which allows for the generation of large amounts of DNA starting from minute quantities obtained from the blood or tissue of a patient. With the increasing knowledge concerning the structure of the human genome and the potential to amplify specific segments of DNA by the PCR technique, the molecular genetic characterization of many ocular disorders has been greatly facilitated. This is particularly true of retinoblastoma (RB) where the causative gene, RB1, gene has been identified and characterized. Using PCR technique, specific sequences of the RB1 gene can be amplified and analyzed to precisely define the genetic mutation in an affected individual. In addition, this technique can also be applied in order to characterize the genetic defect within the tumor itself. In this report we illustrate the use of the PCR technique in the genetic characterization of the RB1 gene and its application to the study of RB. These techniques are applicable even in a small clinical laboratory and can be extended to a number of ophthalmic disorders.

Chromosome Mapping↗
PubMedDate not supplied

Metachronous tumor development in unilateral retinoblastoma.

PURPOSE: A series of 205 retinoblastoma (RB) patients referred to the Department of Ophthalmology at the University of Siena (Italy) was evaluated in order to assess the proportion of unilateral cases later developing tumors in the companion eye ("metachronous" bilateral retinobastoma) (MBRB). METHODS: The total number of unilaterally affected patients developing tumors in the fellow eye was recorded and the risk factors assessed for the development of asynchronous bilateral retinoblastoma, i.e., family history, tumor multifocality and early age at diagnosis. RESULTS: Only two out of 133 (1.5%) unilateral retinoblastoma patients in our series could be considered affected by MBRB. CONCLUSIONS: The incidence of MBRB in our series was negligible (1.5% of all unilateral cases) compared to other reports. None of the reported risk factors for the development of tumors in the fellow eye was relevant in the present series. Although close follow-up of some unilateral cases is still recommended, thorough examination of the fellow eye, to search for lesions in the peripheral retina, is essential in all cases of unilateral RB. MBRB may be a distinctive clinical entity with specific clinical, genetic and prognostic features. However, all these aspects need to be better investigated in larger series.

Follow-Up Studies↗
PubMedDate not supplied

Adult-onset primary glaucoma and molecular genetics: a review.

PURPOSE: To evaluate recent molecular genetic studies focused on localizing and identifying the genes involved in adult-onset primary glaucoma, characterizing the gene products, and investigating the molecular mechanisms implicated in the pathophysiology of the disease. METHODS: Several studies have aimed at understanding gene expression and protein processing and attempting to correlate the mutations identified in the involved genes, particularly the TIGR/MYOC gene, with the overall spectrum of the disease, ranging from juvenile glaucoma to typical late-onset primary open-angle glaucoma. Genetic research remains essential until highly specific and sensitive tests have been developed (plausible disease-causing sequence variations, polymorphisms). RESULTS: The most effective method for detecting glaucoma clinically is the study of optic nerve and visual field damage, as well as intraocular pressure. In subjects at high risk, in members of families with a strong history of inherited glaucoma, and in families with a MYOC-positive test, the result may represent a marker to assess presymptomatic diagnosis and may be useful as a prognostic marker. CONCLUSIONS: OPTN seems to have a role confined to the pathogenesis of normotensive glaucoma with a few exceptions. Presently, the introduction of the expensive and time-consuming OPTN gene test in the current diagnosis of familial glaucoma is not justified.

Adult↗
PubMedDate not supplied

Primary open angle glaucoma in a case of mitochondrial encephalomyopathy (Kearns-Sayre syndrome).

PURPOSE: Kearns-Sayre syndrome is characterized by chronic progressive external ophthalmoplegia, tapetoretinal degeneration and severe generalized myopathy. METHODS AND RESULTS: We report on a 82-year-old male patient with Kearns-Sayre syndrome with open angle glaucoma. DISCUSSION: Reports of primary open angle glaucoma with Kearns-Sayre syndrome are very rare, but it is difficult to believe that this association is merely coincidental.

Aged, 80 and over↗
PubMedDate not supplied

The ophthalmologist's approach to orbital surgery.

In orbital surgery the question arises whether to use the neurosurgical approach or the approaches open to the oculist. Circumscribed and targeted ophthalmological surgery demands a better knowledge of the preoperative anatomical status, CAT study. A-scan, B-scan and M-scan ultrasound studies. The stages common to and distinctive of orbital surgery are: (a) destructive, (b) repair and (c) reconstructive. The importance of orbital microsurgery is stressed, and the choice of approach is discussed.

Cranial Nerve Neoplasms↗
PubMedDate not supplied

[Study on 190 strains of "staphylococcus aureus" isolated in a department of ophthalmology (author's transl)].

Biochemical features and sensitivity to chemotherapeutic agents of 190 strains of Staphylococcus isolated from pharinx and conjunctiva of ophtalmological patients and staff were studied. Each strain was investigated for: pigment, coagulase, hemolysis (alpha-toxin), phosphatase and penicillinase production and mannite fermentation. Twentyfour chemotherapeutic angents were used for sensitivity tests. The Authors emphasize that a positive coagulase test is the best laboratory evidence for pathogenicity of a given strain of Staphylococcus, and that the site of isolation of the examined strains is not related with their biochemical features and sensitivity to chemotherapeutic agents.

Anti-Bacterial Agents↗