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Biomedical subjects

M Lowes

Publications and source records attributed to M Lowes.

12 recordsLinked to original sources
PubMed1998

Retinal detachment after cataract extraction in myopic eyes.

PURPOSE: To determine the incidence of retinal detachment (RD) after cataract extraction in people 40 years of age or older with axial myopia (i.e., axial length > or = 25.5 mm). SETTING: Fifteen Danish eye clinics. METHODS: Two hundred forty-five eyes had cataract extraction performed at 15 eye clinics; 237 eyes had extracapsular cataract extraction (ECCE) and 8 eyes, intracapsular cataract extraction (ICCE). Postoperative data were reported by the practicing ophthalmologists. Mean follow-up was 27 months (range 14 to 32 months). RESULTS: Five RDs occurred in the 245 eyes (2.0%). Excluding the ICCE cases and the two cases of combined cornea transplantation and ECCE, RD occurred in 4 of the 235 eyes that had ECCE (1.7%). The incidence after ECCE with posterior chamber lens implantation was 1.4%. Complete postoperative status was reported on 158 eyes. Forty-eight eyes (30.4%) had a neodymium:YAG capsulotomy and 3 (6.0%) developed an RD 1, 3.5, and 21 months after the capsulotomy. CONCLUSION: The RD incidence after ECCE with posterior chamber lens implantation was low but higher than that in unselected populations. The incidence increased after laser capsulotomy.

Adult↗
PubMed1998

Technical hints for high dose rate interstitial tongue brachytherapy.

High dose rate (HDR) interstitial tongue brachytherapy is a new treatment modality. This study describes important technical details required for its successful use. Thirteen patients with carcinoma of the oral tongue were treated solely with interstitial brachytherapy using HDR remote afterloading techniques during the years 1994-1997. The afterloading catheters were positioned by the submandibular approach with the assistance of a template set. Custom-made mandibular lead shields were inserted prior to treatment. Special reusable Tuen Mun Hospital (TMH) lead buttons were made for improved radiation protection. The median dose given was 55 Gy in ten fractions over 6 days. The interfraction interval was 7 hours for the first seven patients treated and was extended to 8 hours for the other six. Shrinking field techniques were employed and the treatment length of the last fraction was reduced by 5 mm. Commencing with the second patient treated with double planar implants, the medial plane was treated with eight fractions while the lateral plane received ten fractions. To reduce further the potential risk of tract seeding, additional coverage to the implantation tracts was given for the last four patients, with the resultant isodose curves resembling a 'comb rake/brush'. The mean and median measured doses on the inner face of the mandibular shields were 113% and 93% of the reference dose respectively (range 77-247). The dose to the corresponding sites on the gingival surface can be reduced by 75% if the 3 mm thick lead shield is placed successfully. With the use of the TMH button, the transmitted dose to the tissue in direct contact can be reduced by one-third. With the 'comb rake/brush' dose distribution, the high dose volume of the single planar implants could be reduced by 44%, compared with the low dose rate technique, if loading to just 5 mm short of the submandibular skin was required. The mean doses for the combination of eight double planar plus two single planar implants, and ten double planar implants, are on average 29% and 37% greater than the reference dose respectively. An 8% reduction in absolute dose in the region between the planes of the catheters would lead to an even greater magnitude of reduction in morbidity to late responding tissue. The prerequisite for the success of HDR interstitial implants is to develop a good technique in positioning the afterloading catheters and protection of the normal tissue. Its importance merits special attention if HDR remote afterloading interstitial tongue brachytherapy is to realize its full potential.

Brachytherapy↗
PubMed1997

Quantitative reverse transcriptase-PCR amplification of cytokine mRNA in liver biopsy specimens using a non-competitive method.

Reverse transcriptase-PCR (RT-PCR) amplification of mRNA is often the only technique able to detect expression of cytokine mRNA in small samples. The aim of this work was to investigate the utility of a non-competitive RT-PCR which used external standards to quantitate TNF-alpha mRNA in liver biopsy specimens from liver transplant patients. It involved removal of aliquots from the PCR reaction at successive cycles, followed by dot-blotting of the samples onto nylon membrane and hybridization with a radioactively-labelled internal probe. Phosphorimage analysis of the labelled membranes allowed quantitation of the relative amount of PCR product at successive cycles. Plots of log(counts) versus cycle number showed straight lines in the exponential phase of amplification. The slopes of these lines showed the efficiency of amplification, which ranged from 76 to 87% for liver biopsy samples. Estimation of liver biopsy levels of TNF-alpha in two separate PCR amplifications showed low inter-assay variability (r2 = 0.98). Comparison of two separate cDNA syntheses also showed good correlation (r2 = 0.81, P < 0.0001), although not as good as for the PCR alone. This shows that variation in efficiency of cDNA synthesis is likely to contribute as much or more to variability of the analysis as variations in PCR amplification.

Biomarkers↗
PubMed1979

Vitreous cutter in anterior segment surgery.

Experience has been gained in operating upon a variety of anterior segment disorders using a Grieshaber vitreous cutter. The results and complications are briefly discussed.

Anterior Chamber↗
PubMed1978

An evaluation of gliomas of the anterior visual pathways. A 10-year survey.

Thirteen cases of the childhood type of optic glioma from a 10-year period were studied. Particular attention was paid to the pre-operative neuro-ophthalmological and radiological findings. The patients all underwent explorative craniotomy when biopsy specimens were removed for histopathological study. Post-operative radiotherapy was given in 12 cases. In the follow-up period five patients showed deterioration of visual function, three patients showed unchanged visual function, and one patient showed improved visual function. In the remaining four patients, visual function could not be adequately determined. Three patients died in the course of the follow-up period. Retrospectively it was possible, on a histopathological basis, to divide the patients into three groups. It is suggested that the future management of these patients should consist of explorative craniotomy with diagnostic biopsy. Radiotherapy should be confined to selected cases, as only a minority of optic gliomas are radiosensitive.

Adolescent↗
PubMed1977

Placoid pigment epitheliopathy presenting as an anterior uveitis. A case report.

A young woman with acute posterior multifocal placoid epitheliopathy originally presented with signs and symptoms of an anterior uveitis. Prior to the eye condition the patient had experienced headaches and malaise with some muscle and joint tenderness, and had been treated with penicillin because of a dental infection. The clinical and fluorescein angiographic findings are presented. The evidence supports the concept of a primary vascular disturbance of the choriocapillaris with secondary involvement of the retinal pigment epithelium.

Adrenal Cortex Hormones↗
PubMed1976

Visual functions after perinatal macular haemorrhage.

Perinatal macular haemorrhage has been suggested as being a cause of amblyopia and strabismus. 39 of 48 children with macular haemorrhage after birth were examined at the age of 5 years. The study comprised visual acuity with E-test types and cycloplegic refraction. Binocular function was evaluated by cover test, and 4d-prism test. Fixation was studied by an ophthalmoscope with a central dark star. Sensory function was estimated by Schober test and Worth 4-dot-test. The observations gave no support to the existence of organic amblyopia or strabismus following perinatal macular haemmorrhage.

Amblyopia↗
PubMed1976

Progressive external ophthalmoplegia. Evidence for a generalised mitochondrial disease with a defect in pyruvate metabolism.

Muscle biopsies from four patients with chronic progressive external ophthalmoplegia and pigmentary retinopathy with symptoms and signs from other organs were studied by means of light and electron microscopy. Examination revealed a marked proliferation of abnormal mitochondria with a degeneration of both muscle and nerve tissue. Blood levels of lactate and pyruvate were measured and abnormal values of these metabolites were found in the three patients with the most pronounced ultrastructural changes. On the basis of these findings it is suggested that there is a biochemical defect in pyruvate-lactate metabolism which could be responsible for the marked proliferation of the abnormal mitochondria.

Adolescent↗
PubMed1976

Peripheral visual field restriction in chloroquine retinopathy. Report of a case.

Chloroquine compounds are known to cause a retinopathy which typically begins in the central fundus giving rise to a "bull's eye" macula. Ultimately peripheral changes may become apparent. In the routine eye examination of such patients emphasis has been laid on the central area of the fundus. A case is presented where the retinopathy was not diagnosed until marked peripheral changes had occurred with peripheral pigment changes, attenuated retinal vessels, slight optic atrophy, peripheral visual field restriction and a subnormal electroretinogram. The typical "bull's eye" changes were not apparent. Routine examination of the peripheral fundus by means of ophthalmoscopy and perimetry is necessary to avoid missing any such retinopathy.

Adult↗
PubMed1975

Chronic progressive external ophthalmoplegia, pigmentary retinopathy, and heart block (Kearns-Sayre syndrome). Report of a case.

Chronic progressive external ophthalmoplegia associated with a pigmentary retinopathy and heart block was described by Kearns & Sayre in 1958. They suggested that the triad represented a syndrome. The cases recorded since then are reviewed and summarised, and several common features are noted. Little attention has previously been paid to the retinopathy. A similar case is presented, and the pigment changes, retinal function, annd fluorescein angiography are examined. There is no clinical evidence for the diagnosis of classical retinitis pigmentosa. The prognosis and aetiology of the condition are discussed.

Adolescent↗