Photoastigmatic refractive keratectomy--the cure for astigmatism?
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Biomedical subjects
Publications and source records attributed to S Shah.
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OBJECTIVE: To assess whether central corneal thickness (CCT) is a confounding factor in the classification of patients attending for glaucoma assessment in a district general hospital. DESIGN: Cross-sectional study by a single observer. PARTICIPANTS: Patients attending a general ophthalmic clinic: 235 clinically normal eyes, 52 eyes with normal-tension glaucoma (NTG), 335 eyes with primary open-angle glaucoma (POAG), 12 eyes with pseudoexfoliative glaucoma (PXE), 42 eyes with chronic angle closure glaucoma (CACG), and 232 glaucoma suspect (GS) eyes. INTERVENTION: Central corneal thickness was measured using ultrasonic pachymetry. MAIN OUTCOME MEASURE: Correlation of CCT and diagnosis. RESULTS: Mean CCT was 553.9 microm (95% confidence intervals [CI] for the mean, 549.0-558.8 microm) in the clinically normal eyes, 550.1 microm (95% CI, 546.6-553.7 microm) in the POAG eyes, 514.0 microm (95% CI, 504.8-523.3 microm) in the NTG eyes, 530.7 microm (95% CI, 511.2-550.1 microm) in the PXE eyes, 559.9 microm (95% CI, 546.8-573.0 microm) in the CACG eyes, and 579.5 microm (95% CI, 574.8-584.1 microm) in the GS eyes. The differences of mean CCT between the groups were highly significant (P< 0.001 analysis of variance). Eighty-five percent of eyes with NTG and only 36% of eyes with POAG had a mean CCT of 540 microm or less. Thirteen percent of eyes with POAG and 42% of GS eyes had a mean CCT greater than 585 microm. CONCLUSIONS: The CCT measurement is desirable in patients attending for glaucoma assessment in a district general hospital to avoid misclassification resulting from the relationship between CCT and tonometric pressure. Central corneal thickness alone is not an accurate predictor for the clinical diagnosis in this group of eyes. However, many eyes diagnosed as having NTG have thin corneas, which would tend to lower the tonometrically recorded intraocular pressure (IOP), so the finding of a less-than-normal thickness cornea introduces some doubt as to the diagnosis of NTG. For the GS eyes, most eyes had thick corneas, which would tend to increase the tonometrically recorded IOP. Thus, GS eyes with modest elevation of IOP and a thick cornea may be at low risk of progressing to POAG. Thus, many patients with "high IOPs" and a thick CCT do not necessarily have high IOPs and may not need to be followed as GS eyes.
OBJECTIVE: To evaluate the safety and efficacy of retreatment after myopic laser in situ keratomileusis (LASIK). DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: A total of 962 eyes of 566 patients underwent LASIK for up to -20.0 diopters (D) of myopia, of which 53 eyes (5.5%) were retreated. INTERVENTION: Retreatments were performed by lifting the original flap and using the Nidek EC-5000 excimer laser (Nidek Inc., Tokyo, Japan). MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BCVA), fogged manifest refraction, and complications were evaluated 6 months after retreatment. RESULTS: Overall, 53 (5.5%) of 962 eyes underwent LASIK retreatment. Before retreatment, the mean spherical equivalent (MSE) was -1.7 +/- 1.1 D (range, +0.3 to -5.0 D), UCVA ranged from 20/25 to 20/400, and BCVA ranged from 20/20 to 20/50. Six months after retreatment, the MSE was -0.09 +/- 0.29 D, 48 (90.6%) eyes were within +/-0.5 D, and all eyes were within +/-1.0 D of the attempted correction. The UCVA improved to 20/20 or better in 21 (39.6%) eyes and 20/40 or better in 51 (96.2%) eyes. The BCVA was maintained in 33 eyes (62.3%), 15 eyes (28.3%) gained 1 line or more of vision, whereas 5 eyes (9.4%) lost 1 line. All eyes had a BCVA of 20/50 or better. No retreated eye lost two or more lines of BCVA. No complications were observed. CONCLUSION: Retreatment for low amounts of residual myopia performed by lifting the original flap within the first year after surgery after myopic LASIK is safe, effective, and predictable.
The orientation of the acetabular cup and position of lip augmentation (if present) may improve postoperative total hip replacement stability by decreasing dislocation caused by hip prosthesis impingement during rotation. To determine how these cup parameters affect dislocation, the range and amount of rotation for two standard femoral components was determined in a Sawbones hemipelvis model. The parameters that allowed for maximal range of rotation were a cup angle of inclination between 35 degrees and 45 degrees and cup anteversion between 0 degrees and 10 degrees. Cup anteversion angles greater than 20 degrees and cup angles of inclination greater than 45 degrees significantly limited internal and external rotation, particularly for hip flexion greater than 60 degrees. The position of the cup lip augmentation did not affect the amount of rotation except when the hip was flexed and the lip superiorly oriented. Although there are currently devices to facilitate a particular cup position, hip stem type and orientation are other important factors affecting range of rotation that must be considered.
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OBJECTIVE: To assess the accuracy and helpfulness of labelling on products containing probiotic bacteria. DESIGN AND SETTING: 52 such products - 44 from the UK (21 supplements, 15 fermented functional foods, eight 'health-care' products) and eight from continental Europe - have been tested for microbiological content, and results compared to the information available on their labels. Products were stored in the dark at 4 degrees C and analysed before their expiry or sell-by date. Careful note was taken of wording on labels, package inserts, packaging, promotional literature and catalogue descriptions, as applicable. Products were cultured on appropriate bacteriological media, and organisms grown were counted and identified. RESULTS: Bioyoghurts gave no indication of numbers, and only five accurately described their bacterial content; results of culture were usually satisfactory. 'Healthcare' products (mostly intended for the bowel) usually indicated the presence of bacteria, but the numerical content was hard to ascertain, and cultural results fell short of label claims. Supplements were sometimes incorrectly labelled in bacteriological terms, and often contained markedly reduced numbers and/or had extraneous strains and/or strains specified on the label were missing. Products from continental Europe (that were sold for specific medical indications) seemed of a higher microbiological standard. The potential pathogen Enterococcus faecium was found in nine products. The most successful of the new functional foods in Britain now contain probiotics, and probiotic preparations are prominent among the expanding range of nutritional supplements presently available to consumers. CONCLUSIONS: Our findings have public health implications, and suggest that improvements are needed in labelling and quality assurance procedures for products containing probiotic organisms. The presence of the potential pathogen Enterococcus faecium (intentionally or as a contaminant) in some products calls for a review of the value of this species as a probiotic.
PURPOSE: Cytomegalovirus retinitis (CMVR) has been the most common cause of visual loss in AIDS patients. We investigate whether the pattern of disease has changed since the introduction of triple therapy. METHODS: We reviewed the records of all patients with CMVR in one teaching hospital HIV unit over a 2 year period (n = 24). This included the opthalmic and systemic findings, HIV and CMV treatment, survival after diagnosis and CD4 results. RESULTS: There has been a marked decrease in the number of patients developing new CMVR: from 21 eyes (15 patients) to 4 eyes (4 patients) in two consecutive 12 month periods between January 1996 and December 1997, coinciding with the introduction of triple therapy in October 1996. Median survival has increased from 376 days in the deceased patients to 598 days in the survivors on triple therapy. Median time to CMVR relapse has lengthened from 79 to 179 days in the triple therapy cohort. The pattern of ocular morbidity in the 11 eyes of the 7 surviving patients is also changing, with no new zone 1 disease, and a marked rise in the incidence of uveitis, maculopathy and cataracts. CONCLUSION: Results suggest that triple therapy is associated with an increase in survival, a decrease in CMVR relapse and changes in ocular features. This transition has implications for current screening and treatment protocols.
BACKGROUND: Post-enucleation socket syndrome (PESS: deep upper lid sulcus, ptosis or upper lid retraction, enophthalmos and lower lid laxity) is a well-recognised complication of a volume-deficient anophthalmic socket. A patient requiring enucleation following severe ocular trauma may have an underlying orbital wall blow-out fracture which if overlooked can cause severe volume deficit with poor cosmesis and limited prosthesis motility. PURPOSE: To establish the prevalence of an undiagnosed blow-out fracture in patients with PESS and a history of relevant trauma. METHODS: Medical records and orbital computed tomography (CT) scans were reviewed for all patients presenting with PESS and a history of relevant trauma. RESULTS: Undiagnosed blow-out fractures were found in 15 (33%) of 45 patients presenting between August 1993 and December 1996. These were significant enough to warrant surgical repair in 13 (29%) patients. CONCLUSIONS: We suggest that any patient presenting with PESS and a history of relevant trauma should be considered to have an orbital wall blow-out fracture until proven otherwise by CT scanning of the orbit. Similarly any patient requiring enucleation following severe ocular trauma should undergo CT scanning to rule out a coexisting blow-out fracture which could be repaired at the time of enucleation.
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Ketolides represent a new generation of macrolide antibiotics. In order to identify the ketolide-binding site on the ribosome, a library of Escherichia coli clones, transformed with a plasmid carrying randomly mutagenized rRNA operon, was screened for mutants exhibiting resistance to the ketolide HMR3647. Sequencing of the plasmid isolated from one of the resistant clones and fragment exchange demonstrated that a single U754A mutation in hairpin 35 of domain II of the E. coli 23S rRNA was sufficient to confer resistance to low concentrations of the ketolide. The same mutation also conferred erythromycin resistance. Both the ketolide and erythromycin protected A2058 and A2059 in domain V of 23S rRNA from modification with dimethyl sulphate, whereas, in domain II, the ketolide protected, while erythromycin enhanced, modification of A752 in the loop of the hairpin 35. Thus, mutational and footprinting results strongly suggest that the hairpin 35 constitutes part of the macrolide binding site on the ribosome. Strong interaction of ketolides with the hairpin 35 in 23S rRNA may account for the high activity of ketolides against erythromycin-resistant strains containing rRNA methylated at A2058. The existence of macrolide resistance mutations in the central loop of domain V and in hairpin 35 in domain II together with antibiotic footprinting data suggest that these rRNA segments may be in close proximity in the ribosome and that hairpin 35 may be a constituent part of the ribosomal peptidyl transferase centre.
This study examined the effect of energy healing on in vitro tumor cell growth using the cell culture model similar to that embraced by oncologists to assess the effect of chemotherapeutic agents. After selecting an energy healer based on his ability to influence this model, we assessed the effects of energy treatment compared to cells left at ambient temperature and to a control treatment consisting of a medical student mimicking the healer. A chi-square test comparing a medical student's and the practitioner's ability to inhibit tumor cell growth by 15% associates our practitioner with inhibition of tumor cell proliferation (p = 0.02). We also found that the magnitude of change was too close to the assay's intrinsic margin of error, thus making our quantitative data difficult to interpret. Although energy healing appears to influence several indices of growth in in vitro tumor cell proliferation, these assays are limited in their ability to define and prove the existence of this phenomenon. More sensitive biological assays are needed for further study in this field.
The fundamental process of nucleocytoplasmic transport takes place through the nuclear pore. Peripheral pore structures are presumably poised to interact with transport receptors and their cargo as these receptor complexes first encounter the pore. One such peripheral structure likely to play an important role in nuclear export is the basket structure located on the nuclear side of the pore. At present, Nup153 is the only nucleoporin known to localize to the surface of this basket, suggesting that Nup153 is potentially one of the first pore components an RNA or protein encounters during export. In this study, anti-Nup153 antibodies were used to probe the role of Nup153 in nuclear export in Xenopus oocytes. We found that Nup153 antibodies block three major classes of RNA export, that of snRNA, mRNA, and 5S rRNA. Nup153 antibodies also block the NES protein export pathway, specifically the export of the HIV Rev protein, as well as Rev-dependent RNA export. Not all export was blocked; Nup153 antibodies did not impede the export of tRNA or the recycling of importin beta to the cytoplasm. The specific antibodies used here also did not affect nuclear import, whether mediated by importin alpha/beta or by transportin. Overall, the results indicate that Nup153 is crucial to multiple classes of RNA and protein export, being involved at a vital juncture point in their export pathways. This juncture point appears to be one that is bypassed by tRNA during its export. We asked whether a physical interaction between RNA and Nup153 could be observed, using homoribopolymers as sequence-independent probes for interaction. Nup153, unlike four other nucleoporins including Nup98, associated strongly with poly(G) and significantly with poly(U). Thus, Nup153 is unique among the nucleoporins tested in its ability to interact with RNA and must do so either directly or indirectly through an adaptor protein. These results suggest a unique mechanistic role for Nup153 in the export of multiple cargos.
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BACKGROUND: Enteroviruses are common causes of aseptic meningitis and nonspecific febrile illnesses in young children. During the summer-fall months, enterovirus-infected children are frequently evaluated in emergency room settings to rule out bacterial sepsis and/or meningitis. OBJECTIVES: We sought to determine the clinical significance of enterovirus infections in children evaluated for serious febrile illnesses in pediatric emergency rooms during the summer-fall season. METHODS: Children admitted to emergency rooms at four university teaching hospitals during a single summer-fall season who required blood culture and/or lumbar puncture to rule out bacterial sepsis/meningitis were prospectively studied. An extensive questionnaire was administered, and specimens of cerebrospinal fluid, serum, urine and throat were tested for enteroviruses by viral culture and PCR. Patients were followed to determine the duration, management and outcome of their illnesses. RESULTS: Of 203 patients studied 173 had no apparent explanation for their illness (e.g. bacterial sepsis, bacterial urinary tract infection, etc.). Of those 173 patients 79 (46%) were infected with enteroviruses, including 33 of 47 (70%) patients with aseptic meningitis, 13 of 25 (52%) patients with nonspecific febrile episodes and 33 of 101 (33%) patients with fever and focal findings (P < 0.0001 for aseptic meningitis vs. fever and focal findings; P = 0.0001 for aseptic meningitis vs. combined nonspecific febrile episodes and fever/focal patients). Among 119 hospitalized patients 65 (55%) were enterovirus-infected. Children < or =90 days of age were more likely to be enterovirus-infected (66 of 122; 54%) than children older than 90 days (13 of 51; 25%) (P = 0.0001). Enterovirus-infected children were more likely to be hospitalized as a result of the current emergency room visit (65 of 79 vs. 54 of 94; P = 0.0005) and were more likely to have had an additional hospitalization for the same illness (10 of 79 vs. 1 of 94; P = 0.003). Enterovirus-infected patients also had a shorter period from illness onset to presentation. Enterovirus-infected children were indistinguishable from those without enterovirus infection in their symptoms at onset, signs at presentation and total duration of illness (>7 days in both groups). Enterovirus-infected children were almost all treated with antibiotics (78 of 79; 99%), with 74 of 79 (94%) receiving parenteral antibiotics for a mean of 3.6 days. CONCLUSIONS: During the summer-fall months, 39% (79 of 203) of children for whom blood cultures and/or lumbar punctures were performed for suspected bacterial infection had enterovirus infection identified as the only explanation for their illness. Of those patients with no alternative diagnosis, enterovirus infection was confirmed in 46% (79 of 179). The majority of those patients requiring hospitalization were infected with enteroviruses. The use of PCR increases the number of children for whom a specific etiology of illness can be determined and may in the future reduce the hospitalization and use of unnecessary antibiotics in patients with enterovirus infections.
Twenty-eight phenotypically separate strains of clinically isolated vancomycin-resistant enterococci have been investigated with two API identification kit systems (20 Strep and Rapid ID 32 Strep) and two BBL Crystal kits (Gram Positive and Rapid Gram Positive). All strains were identified as Enterococcus faecium by a reference laboratory. The Rapid ID 32 kit positively identified 15 of 28 strains (54%), but only two (7%) were identified correctly: 11 were identified as 'doubtful' or 'to genus level' and two gave 'unacceptable' profiles. The API 20 Strep kit identified 27 strains (96%), but only 16 (57%) were identified correctly as E. faecium. The Rapid ID 32 kit erred by either positively misidentifying vancomycin-resistant E. faecium as E. casseliflavus or E. gallinarum, or indicated that this was the most likely identification, while the API 20 Strep kit more commonly produced a misidentification as E. casseliflavus. The Crystal Gram Positive and Rapid Gram Positive kits correctly identified 26 (93%) and 27 (96%) of the strains, respectively.
BACKGROUND: In July 1996, the National Health and Medical Research Council (NHMRC) published clinical practice guidelines for 'The Procedural and Surgical Management of Coronary Heart Disease'. Despite increasing interest in dissemination and implementation of guidelines, initial reactions to these specific Guidelines and factors critical to their successful implementation had not been determined until our study. AIMS: To determine views of New South Wales (NSW) clinicians towards these NHMRC Guidelines; to identify perceptions about local relevance, usefulness and likely impact and to elicit preferred implementation strategies. METHODS: A postal survey in November 1997 of all cardiologists and cardiothoracic surgeons in NSW. RESULTS: One hundred and ten of 174 clinicians returned the questionnaire (63% response rate). Forty-eight per cent indicated that they were aware of the Guidelines before receiving a copy with the questionnaire while 26% had commented on the draft version of the Guidelines when distributed in November 1995. More than half of respondents 'agreed' or 'strongly agreed' with six of nine statements about potential strengths of the Guidelines. While at least 25% 'disagreed' or 'strongly disagreed' on 11 out of the 13 statements about potential criticisms of the Guidelines, more than half agreed or 'strongly' agreed that the Guidelines did not tell them 'anything they didn't already know'. Fifty-two per cent 'agreed' or 'strongly agreed' that guidelines will be misinterpreted by lawyers. At least 30% rated nine out of 11 implementation strategies as important. Local audits of care and regular feedback, reports from colleagues at conferences and hospital workshops outranked other implementation strategies in encouraging uptake of the Guidelines. CONCLUSIONS: Clinicians in NSW have generally positive views about the Guidelines, however, medicolegal concerns are apparent. To strengthen evidence-based decision-making as exemplified by the Guidelines, audits, presentations by opinion leaders and hospital-based workshops are recommended.