PubMed Health⌕ Search

Biomedical subjects

S J Charles

Publications and source records attributed to S J Charles.

At least 19 recordsLinked to original sources
PubMed2005

The effect of lens design on dysphotopsia in different acrylic IOLs.

PURPOSE: To compare the incidence and severity of all grades of dysphotopsia in three types of acrylic intraocular lenses: the Acrysof MA30 BA and MA60 BM IOLs (Alcon) and the Akreos Fit one-piece IOL (Bausch and Lomb). METHODS: In all 111 patients were prospectively recruited who had undergone uncomplicated cataract surgery in the previous 12 months. Patients were assessed using a combination of a questionnaire and standardised provocation test, and were scored on a grading scale of 0-6 (0 indicating no glare and 6 indicating the most severe symptoms). RESULTS: The overall incidence of dysphotopsia was 77.7%. Patients with absent or mild symptoms (scoring 2 or less on the grading scale) were greater in the group implanted with the Akreos IOLs (49/65 eyes, 75%) as opposed to (44/92 eyes, 48%) of the eyes implanted with Acrysof lenses. Patients with more marked symptoms of glare as judged by scores of 5-6 were uncommon, but more prevalent in the Acrysof lenses (12/92 eyes, 13%) compared to the Akreos lenses (3/65 eyes, 4.6%) respectively. Statistically the Mann-Whitney test showed that there was significantly less dysphotopsia with the Akreos lens when compared to the Acrysof MA30 (P=0.005) and MA60 lenses (P=0.002). CONCLUSION: This study demonstrates that dysphotopsia symptoms are commonly seen in certain brands of Acrylic IOLs. However, differences in design (not only related to the edge) significantly reduce the incidence of moderate and severe grades of dysphotopic symptoms.

Acrylic Resins↗
PubMed2003

Roth's spots: an unusual presentation of HIV.

A 46 year old Nigerian man presented with a four week history of progressive bilateral visual loss. He had been unwell, with weight loss, fever, and night sweats for six months. Dilated fundoscopy revealed macular haemorrhages and diffuse Roth's spots. The patient was found to be severely anaemic and a bone marrow aspirate revealed a T cell lymphoma with a decreased CD4+ T cell count. The patient consented for testing for HIV which proved positive.

Anemia↗
PubMed2001

Diverse prevalence of large deletions within the OA1 gene in ocular albinism type 1 patients from Europe and North America.

Ocular albinism type 1 (OA1) is an X-linked disorder mainly characterized by congenital nystagmus and photodysphoria, moderate to severe reduction of visual acuity, hypopigmentation of the retina, and the presence of macromelanosomes in the skin and eyes. We have previously isolated the gene for OA1 and characterized its protein product as melanosomal membrane glycoprotein displaying structural and functional features of G protein-coupled receptors. We and others have identified mutations of various types within the OA1 gene in patients with this disorder, including deletions and splice site, frameshift, nonsense, and missense mutations. However, different prevalences of large intragenic deletions have been reported, ranging from 10% to 50% in independent studies. To determine whether these differences might be related to the geographic origin of the OA1 families tested, we performed a further extensive mutation analysis study leading to the identification of pathogenic mutations in 30 unrelated OA1 patients mainly from Europe and North America. These results, together with our earlier mutation reports on OA1, allow us to resolve the apparent discrepancies between previous studies and point to a substantial difference in the frequency of large intragenic deletions in European (<10%) compared with North American (>50%) OA1 families. These observations and our overall refinement of point mutation distribution within the OA1 gene have important implications for the molecular diagnosis of OA1 and for the establishment of any mutation detection program for this disorder.

Albinism, Ocular↗
PubMed2001

Candida endophthalmitis: an unusual complication of prolonged intravenous access.

A 16 year old boy awaiting a defunctioning colostomy for Crohn's disease complained of reduced vision in his left eye. Four weeks previously candida had been isolated from his central line used for parenteral feeds. Fundal examination of the left eye revealed a macular abscess with a classic "string of pearls" appearance of multiple vitreous abscesses. This was treated with pars plana vitrectomy and intravitreal antifungal therapy. Microbiological studies confirmed a diagnosis of candida endophthalmitis.

Adolescent↗
PubMed2000

Extended and Point Defects in Diamond Studied with the Aid of Various Forms of Microscopy.

It is shown that star disclinations can be a significant source of stress in chemical vapor deposited (CVD) diamond. This purely geometrical origin contrasts with other sources of stress that have been proposed previously. The effectiveness is demonstrated of the use of electron irradiation using a transmission electron microscope (TEM) to displace atoms from their equilibrium sites to investigate intrinsic defects and impurities in CVD diamond. After irradiation, the samples are studied by low temperature photoluminescence microscopy using UV or blue laser illumination. Results are given that are interpreted as arising from isolated <100> split self-interstitials and positively charged single vacancies. Negatively charged single vacancies can also be revealed by this technique. Nitrogen and boron impurities may also be studied similarly. In addition, a newly developed liquid gallium source scanned ion beam mass spectrometry (SIMS) instrument has been used to map out the B distribution in B doped CVD diamond specimens. The results are supported by micro-Raman spectroscopy.

Journal Article↗
PubMed2000

The changing pattern of cytomegalovirus retinitis in human immunodeficiency virus disease.

There have been profound changes in the pattern of cytomegalovirus (CMV) retinitis over the last two decades. The epidemiology and behaviour of CMV retinitis has been significantly altered by Acquired Immune Deficiency Syndrome (AIDS). It was uncommon prior to the AIDS epidemic, but soon became the most common retinal infection in AIDS patients. In the past several years, highly active anti-retroviral treatment (HAART) has achieved a dramatic improvement in the prognosis for patients infected with human immunodeficiency virus (HIV). As a result, HIV patients are living longer and have a reduced risk of CMV retinitis. Some patients with CMV retinitis who respond to HAART develop a transient symptomatic vitritis while others undergo no reactivation of their retinitis despite having no specific anti-CMV therapy. This pattern is likely to undergo further change as the treatment of HIV and CMV disease continues to improve.

AIDS-Related Opportunistic Infections↗
PubMed1999

Carcinoma of the ovary with primary presentation in the choroid.

PURPOSE: An unusual case of choroidal metastases from an ovarian adenocarcinoma is described, and a brief review of the literature is presented. METHODS: Clinical and autopsy findings are presented. RESULTS: After having diagnosed bilateral choroidal metastatic lesions, a clinical investigation and a subsequent laparotomy disclosed bilateral ovarian tumors with histopathological features of mucinous adenocarcinoma. At autopsy the tumor was confirmed to be a primary ovarian mucinous adenocarcinoma with choroidal metastases. CONCLUSION: This article describes what is believed to be the first case report of a primary epithelial carcinoma of the ovary with histopathologically documented metastases to the choroid. Metastatic disease must be considered in the evaluation of patients with choroidal lesions of unknown etiology.

Adenocarcinoma, Mucinous↗
PubMed1999

Cytomegalovirus retinitis in patients with acquired immune deficiency syndrome.

Cytomegalovirus (CMV) retinitis is the most common intra-ocular infection in patients with acquired immune deficiency syndrome (AIDS), and a leading cause of AIDS-related morbidity. Untreated CMV retinitis in AIDS patients is a progressive and potentially blinding disorder. The diagnosis of CMV retinitis is a clinical one and it is important for physicians to be familiar with the clinical features of the disease. Ophthalmic screening of AIDS sufferers should be undertaken at regular intervals, and this is dictated, in part, by the patient's CD4+ T-lymphocyte (CD4) counts. CMV retinitis may be treated with systemic ganciclovir, foscarnet or cidofovir, or with local (intravitreal) therpy. CMV-related retinal detachment is treated surgically. In some patients with quiescent CMV retinitis receiving highly active anti-retroviral therapy, anti-CMV maintenance therapy may be discontinued in favour of close ophthalmologic observation and CD4 count monitoring.

Anti-HIV Agents↗
PubMed1997

Objective morphological assessment of macular hole surgery by scanning laser tomography.

AIM: To assess the morphological change in retinal topography using a scanning laser tomographer following macular hole surgery. To compare the results of scanning laser tomography with clinical evaluation and visual function assessment. METHODS: The sample for this pilot study comprised four eyes exhibiting different stages of macular hole formation preoperatively. Subjects were assessed preoperatively and at 1 and 3 months postoperatively. Each assessment included visual acuity, letter contrast sensitivity, clinical examination (including automated static perimetry), and scanning laser tomography. The Heidelberg retina tomograph (HRT) was used to acquire digitised scanning laser tomography images of the macula (10 degrees and 20 degrees fields). Surgery essentially comprised vitrectomy, peeling of the posterior hyaloid face, if still attached, and intraocular gas tamponade. The magnitude and significance of topographic change were determined postoperatively using the HRT topographic difference facility. RESULTS: Topographic difference analysis of the right and left eyes of case 1 showed a significant reduction in the height of the retina postoperatively. Topographic difference analysis of case 2 showed no significant change in topography. Topographic difference analysis of case 3 showed a significant increase in the height of the retina postoperatively. Scanning laser tomography agreed with clinical assessment based upon fundus biomicroscopy in three of the four eyes studied; the postoperative closure of the stage 2 macular hole (as noted by clinical assessment) proved to be too small to reach statistical significance. Scanning laser tomography agreed with the assessment of visual function in two eyes; the agreement between scanning laser tomography and visual function depends, in part, on the stage of development of the macular hole. CONCLUSION: Scanning laser tomography provides an objective evaluation of the outcome of macular hole surgery. Studies employing larger sample sizes are required to fully determine the clinical worth of the technique.

Adult↗
PubMed1995

Analysis of the OA1 gene reveals mutations in only one-third of patients with X-linked ocular albinism.

The locus for ocular albinism type 1 (OA1) has been assigned to the Xp22.3 region through both linkage and deletion mapping. The disorder was found to be genetically homogeneous, as all informative families showed convincing linkage data with markers on Xp22.3 and all identified deletions involved in the same region. The OA1 gene recently was cloned and several intragenic deletions were identified in affected individuals. We have characterized the genomic structure of the OA1 gene, which spans approximately 40 kb of genomic DNA and contains nine exons. A highly polymorphic dinucleotide repeat was identified in intron 1, that provides a useful tool for molecular diagnosis. Knowledge of the intron/exon boundaries allowed us to search for point mutations in patients' genomic DNA. All nine exons of the OA1 gene, as well as the 5' and 3' untranslated regions, were scanned for point mutations in PCR-amplified DNA from 60 OA1 patients. The mutations identified include: two frameshifts and a splice site mutation leading to truncated OA1 proteins; a deletion of a threonine codon at position 290; and four missense mutations,two of which involve amino acids located within putative transmembrane domains. Two of the mutations each occur in three apparently unrelated families, consistent with previous observations of a founder effect in OA1. Surprisingly, mutations were detected in only one-third of the patients (21 of 60) ascertained. We postulate that mutations not yet identified in either regulatory elements of the OA1 gene, or in other gene(s) located within the same chromosomal region, may be common cause of X-linked ocular albinism.

Albinism, Ocular↗
PubMed1995

Marfan syndrome: fibrillin expression and microfibrillar abnormalities in a family with predominant ocular defects.

We have found abnormal fibrillin microfibrils isolated from tissues and cell cultures from two cousins with Marfan syndrome whose major clinical abnormality is bilateral ectopia lentis, but who also have skeletal involvement but no cardiovascular defects. Ultrastructural analysis of ciliary zonules showed the presence of abundant loose microfibril bundles which in many places appeared disorganised. Microfibrils isolated from ciliary zonules and vitreous were highly fragmented when examined by rotary shadowing electron microscopy. Investigation of microfibrils elaborated by patient dermal fibroblasts showed remarkable variations in periodicity and packing. The synthesis and secretion of fibrillin by these cells was confirmed electrophoretically with the identification of metabolically labelled immunoprecipitated fibrillin (M(r) 300,000) in medium and cell layer compartments. These data show that fibrillin expression is normal but that assembled microfibrils are manifestly abnormal both morphologically and functionally. The occurrence of microfibrils with variable periodicities and susceptibility to fragmentation suggests that structural weakness is probably the primary cause of lens dislocation in these patients.

Actin Cytoskeleton↗
PubMed1994

Carrier detection in X linked ocular albinism using linked DNA polymorphisms.

Sixty two females at 50% carrier risk were assessed from 19 families affected by X linked ocular albinism (OA1). Twenty nine (47%) had definite fundus changes of the carrier state with a mud splattered fundus appearance and 23 (37%) had a normal ophthalmic examination. Ten (16%) had mild peripheral retinal pigmentary changes so that it was difficult to exclude the carrier state; six of these females were shown to be at low risk and only one at high risk of being a carrier by DNA analysis using linked DNA polymorphisms, including a highly informative dinucleotide repeat at the Kallmann locus. Mild peripheral retinal pigmentary changes are not a definite indication of carrier status and in 45 age matched female controls five (11%) had similar changes. No female with a clinically normal fundus was found to be at high risk by DNA analysis. Molecular genetic analysis improves the accuracy of carrier detection in OA1 families and should be considered if the clinical findings are equivocal.

Albinism, Ocular↗
PubMed1994

Cocaine hepatotoxicity: a study on the pathogenesis of periportal necrosis.

Cocaine is reported to produce either periportal or mid-zonal necrosis in mice pretreated with the enzyme inducer phenobarbitone (James et al. 1987; Powell et al. 1991; Charles & Powell 1992). Dose-response and time course experiments were performed in phenobarbitone treated male DBA/2Ha mice to study the pathogenesis of this unusual cocaine induced lesion. An increase in the dose of cocaine from 60 to 90 or 120 mg/kg produced more extensive and severe periportal and linking portal damage and elevated plasma aspartate (AST) and alanine (ALT) aminotransferases in a dose dependent manner. Scattered hepatocyte degeneration began at the edge of the periportal region and was detectable by electron microscopy within 30 minutes of administration of 60 mg/kg of cocaine, with conspicuous disorganization of the endoplasmic reticulum being one of the earliest changes. Significant elevations of plasma AST and ALT were observed 3 hours after cocaine administration and were sustained for 12 hours, at which time progressive hepatocyte damage had developed into a network of confluent necrosis at the periphery of the periportal region. The rapidity of organelle derangement and subsequent cell death, and absence of any effect on total cytochrome P-450 or FAD-mono-oxygenase levels, appear to distinguish this periportal lesion from previous reports of cocaine induced centrilobular necrosis in non-enzyme induced mice, suggesting that the two types of damage may develop by different mechanisms. The observation that periportal lesions commence at the periphery of the periportal area, progressing portalwards with increasing dose and time, offers an explanation for the previously conflicting reports of cocaine induced mid-zonal and/or periportal lesions in phenobarbitone treated mice.

Alanine Transaminase↗
PubMed1993

Genetic mapping of X-linked ocular albinism: linkage analysis in a large Newfoundland kindred.

Genetic linkage studies in a large Newfoundland family affected by X-linked ocular albinism (OA1) showed linkage to markers from Xp22.3. One recombinant mapped the disease proximal to DXS143 (dic56) and two recombinants mapped the disease distal to DXS85 (782). Combining the data with that from 16 British families previously published confirmed close linkage between OA1 and DXS143 (dic56; Zmax = 21.96 at theta = 0.01, confidence interval (CI) 0.0005-0.05) and linkage to DXS85 (782; Zmax = 17.60 at theta = 0.07, CI = 0.03-0.13) and DXS237 (GMGX9; Zmax = 15.20 at theta = 0.08, CI = 0.03-0.15). Multipoint analysis (LINKMAP) gave the most likely order as Xpter-XG-DXS237-DXS 143-OA1-DXS85, with odds of 48:1 over the order Xpter-XG-DXS237-OA1-DXS143-DXS85, and odds exceeding 10(10):1 over other locations for the disease locus.

Albinism, Ocular↗