Comparing approaches to screening for angle closure in older Chinese adults

AIMS

Primary angle-closure glaucoma is expected to account for nearly 50% of bilateral glaucoma blindness by 2020. This study was conducted to assess the performance of the scanning peripheral anterior chamber depth analyzer (SPAC) and limbal anterior chamber depth (LACD) as screening methods for angle closure.

METHODS

This study assessed two clinical populations to compare SPAC, LACD, and gonioscopy: the Zhongshan Angle-closure Prevention Trial, from which 370 patients were eligible as closed-angle participants and the Liwan Eye Study, from which 72 patients were selected as open-angle controls. Eligible participants were assessed by SPAC, LACD, and gonioscopy.

RESULTS

Angle status was defined by gonioscopy. Area under the receiver operating characteristic curve (AUROC) for SPAC was 0.92 (0.89-0.95) whereas AUROC for LACD was 0.94 (0.92-0.97). Using conventional cutoff points, sensitivity/specificity was 93.0%/70.8% for SPAC and 94.1%/87.5% for LACD. Sequential testing using both SPAC and LACD increased the specificity to 94.4% and decreased the sensitivity to 87.0%.

CONCLUSION

SPAC has significantly lower specificity than LACD measurement using conventional cutoffs but interpretation of the findings can be performed by modestly trained personnel.

Increased iris thickness and association with primary angle closure glaucoma

AIMS

To investigate the relationship between quantitative iris parameters and angle closure disease. methods: Participants with angle closure were recruited prospectively from glaucoma clinics. Anterior segment optical coherence tomography (AS-OCT) was performed under standardised dark conditions. Customised software was used on horizontal AS-OCT scans to measure iris thickness at 750 um (IT750) and 2000 um (IT2000) from the sclera spur, maximal iris thickness (ITM) and cross-sectional area of the iris (I-Area).

RESULTS

167 Angle closure (consisting of 50 primary angle-closure (PAC), 73 primary angle closure glaucoma (PACG) and 44 fellow eyes of acute PAC) and 1153 normal participants were examined. After adjusting for age, sex, pupil size and anterior chamber depth, mean IT750 (0.499 vs 0.451 mm, p<0.001), IT2000 (0.543 vs 0.479 mm, p<0.001), ITM (0.660 vs 0.602 mm, p<0.001) and I-Area (1.645 vs 1.570 mm(2), p=0.014) were significantly greater in angle closure (combined groups) versus normal eyes. Multivariate adjusted odd ratios (OR) of each parameter for the angle closure as compared with normal eyes were: IT750 OR1.7 (95% CI 1.1 to 2.7, p=0.032); IT2000 OR2.2 (95% CI 1.3 to 3.8, p=0.006) and ITM OR2.2 (95% CI 1.3 to 3.6, p=0.003), respectively, per 0.1 unit increase.

CONCLUSIONS

Increased iris thickness is associated with angle closure.

Degree of angle closure and extent of peripheral anterior synechiae: an anterior segment OCT study

AIMS

To evaluate the relationship between angle width as determined by anterior segment optical coherence tomography (AS-OCT) and the presence of peripheral anterior synechiae (PAS).

METHODS

This was a prospective observational case series in which 203 subjects with primary angle closure or open angles were recruited. Images of the nasal, temporal and inferior angles were obtained with AS-OCT in dark conditions. Subjects then underwent gonioscopy by an independent examiner who was masked to the AS-OCT findings. PAS were identified by gonioscopy and defined as abnormal adhesions of the iris to the angle that were at least half a clock hour in width and present to the level of the anterior trabecular meshwork or higher. The total clock hours of PAS were recorded.

RESULTS

Sixty-eight subjects (33.5%) were PACS, 76 subjects (37.4%) had PAC/PACG, 14 (6.9%) had primary open angle glaucoma, and 45 (22.2%) subjects were normal with open angles. There was a weak but significant correlation between the angle opening distance (AOD), trabecular iris space area (TISA) and angle recess area (ARA) with clock hours of PAS (Spearman's correlation coefficients = -0.30, -0.32 and -0.32, respectively, p<0.001). The mean values of the AOD, TISA and ARA in the nasal, temporal and inferior quadrants were significantly less in eyes with PAS compared with those without (p<0.001, Mann-Whitney U test). Analysis by quadrant showed that these parameters were smaller in the nasal and temporal quadrants in eyes with PAS (p<0.01).

CONCLUSIONS

Angle width determined by AS-OCT and the extent of PAS were weakly correlated, and angle width was significantly smaller in eyes with PAS.

Lens extraction for chronic angle-closure glaucoma

BACKGROUND

Angle-closure glaucoma is characterized by obstruction to the outflow of aqueous humor and consequent rise in intraocular pressure. The obstruction may result from an anatomical predisposition of the eye or may be due to pathophysiologic processes in any part of the eye. The former is considered the primary form and the latter a secondary form of angle closure. Relative pupillary block obstructing free flow of aqueous from the posterior chamber of the eye to the anterior chamber is considered to be the most common mechanism of angle closure. Crowding of the angle is another mechanism, which often coexists with pupillary block. This can result from an anterior placement of the lens due to an increase in the thickness of the lens (as occurs with aging), anterior displacement by a posterior force (for example choroidal effusion), or laxity of the zonules.

OBJECTIVES

The objective of this review was to assess the effectiveness of lens extraction for chronic primary angle-closure glaucoma compared with other interventions for the condition in people without past history of acute-angle closure attacks.

SEARCH STRATEGY

We searched CENTRAL (2005, Issue 3), MEDLINE (1950 to April 2006), EMBASE (1980 to April 2006), and LILACS (to August 2005). We searched the reference lists of included studies and used the Science Citation Index database.

SELECTION CRITERIA

In the absence of any randomized trials we included non-randomized studies comparing lens extraction with other treatment modalities for chronic primary angle-closure glaucoma including, but not limited to, laser iridotomy, medications, and laser iridoplasty. We excluded studies with a case-series design.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data on methodological quality of the included studies, outcomes for the review, and study characteristics including participant characteristics, interventions, and sources of funding. Differences were resolved through discussion.

MAIN RESULTS

We found no randomized trials evaluating the effects of lens extraction as a treatment for chronic primary angle-closure glaucoma. Two non-randomized comparative studies included in the review have several methodological flaws including selection bias. While these studies and other non-comparative studies provide information on biological plausibility and treatment effect they do not provide proof of effectiveness. Also, they do not address the question of how primary lens extraction compares with other treatments for chronic primary angle-closure glaucoma.

AUTHORS' CONCLUSIONS

There is no evidence from good quality randomized trials or non-randomized studies of the effectiveness of lens extraction for chronic primary angle-closure glaucoma.

An outbreak of norovirus gastroenteritis associated with wedding cakes

We sought to determine the source of a norovirus outbreak among attendees of 46 weddings taking place during a single weekend. Norovirus-compatible illness was experienced by 332 (39%) of wedding guests surveyed; the outbreak affected up to 2700 persons. Illness was associated with eating wedding cake provided by a bakery common to the weddings (adjusted RR 4.5, P<0.001). A cake requiring direct hand contact during its preparation accounted for the majority of illness. At least two bakery employees experienced norovirus-compatible illness during the week preceding the weddings. Identical sequence types of norovirus were detected in stool specimens submitted by two wedding guests, a wedding hall employee, and one of the ill bakery employees. It is likely that one or more food workers at the bakery contaminated the wedding cakes through direct and indirect contact. These findings reinforce the necessity of proper food-handling practices and of policies that discourage food handlers from working while ill.

Patient preferences for anaesthesia management during cataract surgery

BACKGROUND/AIMS

To assess patient preferences for different anaesthesia management strategies during cataract surgery.

METHODS

Cross sectional clinic based study of patient preferences for anaesthesia management strategies. Patients rated their preferences using a linear rating scale from 0 to 100.

RESULTS

Subjects tended to prefer block to topical anaesthesia and oral to intravenous sedation. On a scale from 0 to 100, subjects preferred oral to intravenous sedation and block to topical anaesthesia by about 8 points.

CONCLUSIONS

When given the choice of four different anaesthesia management strategies, 72% of the study subjects preferred block anaesthesia to topical anaesthesia. More patients chose to have oral sedation than intravenous sedation. These findings indicate that patients may prefer anaesthesia management approaches other than the ones they are currently being offered.

VF-14 item specific responses in patients undergoing first eye cataract surgery: can the length of the VF-14 be reduced?

AIMS

To report the item specific responses of the VF-14 in a population of patients undergoing cataract surgery in their first eye and to determine whether or not the VF-14 can be reduced without compromising its performance as an index of cataract related visual impairment.

METHODS

The item specific responses to the VF-14 were analysed before (771 patients) and 4 months after (552 patients) cataract surgery in one eye to determine if the VF-14 index can be reduced without compromising its performance. Patients studied were selected from a cross sectional longitudinal study of patients undergoing cataract surgery in 72 ophthalmologist's offices located in three metropolitan regions of the United States.

RESULTS

Pairwise correlations between items in the VF-14 were all less than 0.6, indicating that no items could be removed solely on the basis of redundancy. 10 items correlated moderately with change in trouble, and 11 correlated moderately with change in satisfaction (r >0.15) at 4 months after cataract extraction. Eleven items demonstrated an effect size >0.4 at 4 months. These 11 items were either important for detecting cataract related functional disability or for quantifying the extent to which cataract impaired function. Additionally, 11 items were needed to detect adequately individuals with functional impairment. Three items (recognising people, cooking, and reading large print) were less responsive to cataract extraction and were more strongly associated with ocular comorbidities.

CONCLUSIONS

While previous reports indicate that the VF-14 can be significantly shortened, our analysis only justifies removing three items. While the resulting VF-11 has properties similar to the VF-14, the limited time savings do not justify altering this already validated instrument.

A decision analysis of anesthesia management for cataract surgery

PURPOSE

To compare the trade-offs in cost and preference of various anesthesia management strategies for cataract surgery.

METHODS

Six strategies, differing in sedation, local anesthetic, and monitoring approach, were chosen for comparison. For each strategy, potential complications, and conversions to different anesthesia approaches were modeled. A panel of physicians and anesthetists, well versed in the literature and practice of the anesthesia management of cataract surgery, assigned preference values to the strategies and potential outcomes (0 to 1 scale). Probability estimates were obtained from a study of 19,557 cataract surgeries and from the panel. Cost estimates were derived from several sources. The model was analyzed to determine the strategies associated with the highest expected preference and lowest expected cost.

RESULTS

The strategy associated with the highest net preference was intravenous sedation with block anesthesia and an anesthesiologist present throughout the case. The expected net preference for this strategy was 19% greater than the net preference for the next most preferred strategy, oral sedation with block anesthesia and an anesthesiologist on call (0.88 versus 0.74), but the expected anesthesia costs per case were much greater ($324 versus $42). Results were sensitive to plausible variation in the preference values assigned to the six initial management strategies and to the cost of topical versus block anesthesia.

CONCLUSION

This analysis emphasizes that cost and preference are important considerations when choosing an anesthesia management strategy for cataract surgery. For some surgeries, substantial cost savings may be available for a small change in preference.

Activity restrictions as part of the discharge management for children with a traumatic head injury

This article describes a proactive management strategy that is currently part of the discharge protocol for children seeking care for a head injury (HI) at a pediatric and adolescent trauma center. The strategy consists of setting activity restrictions for children hospitalized and those seen in the emergency department after a HI that may or not have been sports related. It was developed based on extensive clinical experience with families of children with a HI and existing guidelines for returning athletes to sports. Possible merits and pitfalls of the strategy are discussed.

The methodologic quality of clinical trials on regional anesthesia for cataract surgery

OBJECTIVE

To assess the methodologic quality of published randomized trials of regional anesthesia management strategies for cataract surgery.

DESIGN

Literature review and analysis.

METHOD

We performed a systematic search of the literature to identify all articles pertaining to regional anesthesia for cataract surgery on adults. Overall quality scores and scores for individual methodologic domains were based on the evaluations of two investigators experienced in methodologic research who independently reviewed all relevant articles using a quality abstraction form.

MAIN OUTCOME MEASURES

Study quality in each of five domains: representativeness, bias and confounding, intervention description, outcomes and follow-up, and statistical quality and interpretation.

RESULTS

Eighty-two randomized clinical trials were identified with a mean overall quality score of 44%. The mean domain scores ranged from 37% for representativeness to 58% for outcomes and follow-up. Forty percent or fewer studies received the maximum score for reporting the setting, the population, and the start and end dates; describing the inclusion and exclusion criteria; adequately randomizing subjects; and adequately masking individuals participating in the study. Key outcomes were often inadequately reported, including the distribution of patient-reported pain scores and the mean surgical time.

CONCLUSIONS

Greater attention to methodologic quality and detailed reporting of study results will improve the ability of readers to interpret the results of clinical trials assessing regional anesthesia for cataract surgery.

Synthesis of the literature on the effectiveness of regional anesthesia for cataract surgery

OBJECTIVE

To synthesize the findings of the randomized trials of regional anesthesia management strategies for cataract surgery.

DESIGN

Literature review and analysis.

METHOD

The authors performed a systematic search of the literature to identify all articles pertaining to regional anesthesia during cataract surgery on adults. One investigator abstracted the content of each article onto a custom-designed form. A second investigator corroborated the findings. The evidence supporting the anesthesia approaches was graded by consensus as good, fair, poor, or insufficient.

MAIN OUTCOME MEASURES

Evidence supporting the effectiveness of different forms of regional anesthesia.

RESULTS

There was good evidence that retrobulbar and peribulbar blocks provide equivalent akinesia and pain control during cataract surgery. Additionally, sub-Tenon's blocks were at least as effective as retrobulbar and peribulbar blocks. There was good evidence that retrobulbar block provides better pain control during surgery than topical anesthesia, and there was fair evidence that peribulbar block provides better pain control than topical anesthesia.

CONCLUSIONS

This synthesis of the literature demonstrates that currently used approaches to anesthesia management provide adequate pain control for successful cataract surgery, but there is some variation in the effectiveness of the most commonly used techniques. Data are needed on patient preferences to determine the optimal strategies for anesthesia management during cataract surgery.

Diagnostic capabilities of frequency-doubling technology, scanning laser polarimetry, and nerve fiber layer photographs to distinguish glaucomatous damage

PURPOSE

To investigate the ability of three diagnostic tests: frequency-doubling technology (FDT), scanning laser polarimetry (GDx), and nerve fiber layer (NFL) photographs to distinguish normal from glaucomatous eyes.

METHODS

Data were obtained in a cross-sectional, hospital clinic-based study, including one eye from each of 253 persons older than 40 years (68 normal, 94 glaucoma suspects and 91 glaucoma patients). We performed a comprehensive ocular examination, as well as static automated perimetry (Humphrey 24-2), screening FDT, GDx, optic nerve stereoscopic photographs and high-contrast NFL photographs.

RESULTS

The following were significantly different for glaucomatous patients compared with suspects and normals: mean values of mean deviation (MD, Humphrey 24-2) and corrected pattern standard deviation (CPSD), 11 GDx indices, mean FDT testing time and missed points, and NFL graded defects (ANOVA, Mantel-Haenszel test; p = 0.0001). Using Humphrey 24-2 test results and clinical assessment as the defining features of glaucoma, we found that the optimal mix of sensitivity and specificity values were 84% and 100% for FDT (presence of any defect); 62% and 96% for GDx (The Number, cut-off value of 27); and, 95% and 82% for NFL photographs (presence of any abnormality). FDT testing took the least time to be administered.

CONCLUSIONS

The FDT had the best diagnostic performance. Neural network analysis of GDx data outperformed other elements of its software.

Effectiveness of a head injury program for children: a preliminary investigation

OBJECTIVE

The purpose of this study was to investigate whether a more coordinated, comprehensive head injury rehabilitation program provided at a children's trauma center yielded better outcomes than a less coordinated, less comprehensive program.

DESIGN

Using a quasi-experimental design, 64 children with head injury admitted to the center and who received rehabilitation services in either 1995 or 1993 were evaluated by using the Functional Independence Measure for children (WeeFIM)/The Functional Independence Measure (FIM) (e.g., primary outcome measure). Secondary outcomes included "psychosocial adjustment," "return to regular school," and "current problems related to the head injury."

RESULTS

No statistically significant differences were found between the groups with respect to mean WeeFIM/FIM scores after controlling for age and injury severity. The 1993 group had poorer scores on the withdrawal subscale of the psychosocial measure (P = 0.02), yet a smaller proportion of these children were enrolled in a special education class (P = 0.02).

CONCLUSIONS

This study serves as a model for a larger, definitive study of the effectiveness of rehabilitation for children with head injury. The trends suggest that more comprehensive care may lead to better outcomes.

Algorithm for interpreting the results of frequency doubling perimetry

PURPOSE

To evaluate an algorithm for the identification of glaucomatous visual field defects with the screening mode of frequency doubling technology.

METHODS

Screening-mode frequency doubling technology and Swedish interactive threshold algorithm perimetry were performed on 137 of 150 consecutive patients referred to a glaucoma specialist. We created an algorithm for the frequency doubling technology that gave increased importance to both more severe defects and defects closer to fixation. These values were then compared with the results of the Swedish interactive threshold algorithm visual fields evaluated by the glaucoma hemifield test, two masked glaucoma specialists, and a published definition of glaucomatous damage to determine sensitivity and specificity of the frequency doubling technology screening mode for detecting glaucoma.

Single-molecule analysis of kinesin motility reveals regulation by the cargo-binding tail domain

Conventional kinesin transports membranes along microtubules in vivo, but the majority of cellular kinesin is unattached to cargo. The motility of non-cargo-bound, soluble kinesin may be repressed by an interaction between the amino-terminal motor and carboxy-terminal cargo-binding tail domains, but neither bead nor microtubule-gliding assays have shown such inhibition. Here we use a single-molecule assay that measures the motility of kinesin unattached to a surface. We show that full-length kinesin binds microtubules and moves about ten times less frequently and exhibits discontinuous motion compared with a truncated kinesin lacking a tail. Mutation of either the stalk hinge or neck coiled-coil domain activates motility of full-length kinesin, indicating that these regions are important for tail-mediated repression. Our results suggest that the motility of soluble kinesin in the cell is inhibited and that the motor becomes activated by cargo binding.

Methodological variations in estimating apparent progressive visual field loss in clinical trials of glaucoma treatment

OBJECTIVES

To compare methods to estimate the incidence of visual field progression used by 3 large randomized trials of glaucoma treatment by applying these methods to a common data set of annually obtained visual field measurements of patients with glaucoma followed up for an average of 6 years.

METHODS

The methods used by the Advanced Glaucoma Intervention Study (AGIS), the Collaborative Initial Glaucoma Treatment Study (CIGTS), and the Early Manifest Glaucoma Treatment study (EMGT) were applied to 67 eyes of 56 patients with glaucoma enrolled in a 10-year natural history study of glaucoma using Program 30-2 of the Humphrey Field Analyzer (Humphrey Instruments, San Leandro, Calif). The incidence of apparent visual field progression was estimated for each method. Extent of agreement between the methods was calculated, and time to apparent progression was compared.

RESULTS

The proportion of patients progressing was 11%, 22%, and 23% with AGIS, CIGTS, and EMGT methods, respectively. Clinical assessment identified 23% of patients who progressed, but only half of these were also identified by CIGTS or EMGT methods. The CIGTS and the EMGT had comparable incidence rates, but only half of those identified by 1 method were also identified by the other.

CONCLUSIONS

The EMGT and CIGTS methods produced rates of apparent progression that were twice those of the AGIS method. Although EMGT, CIGTS, and clinical assessment rates were comparable, they did not identify the same patients as having had field progression.

Digital image capture and automated analysis of posterior capsular opacification

PURPOSE

To develop and validate a digital imaging and analysis technique for assessing the extent of posterior capsular opacification after cataract surgery.

METHODS

Retroillumination images of the posterior capsule were obtained by using a digital camera mounted on a slit lamp. The images were analyzed using an available image analysis software program. The image acquisition and analysis techniques were tested for face validity, reproducibility, and the ability to detect progression of capsular opacity over time.

RESULTS

Digital retroillumination images were obtained without patient discomfort. Automated analysis of images correlated well with clinical grading both at slit lamp examination and when looking at the images themselves (Spearman's correlation coefficient >0.7). Analysis of images taken at different times showed high reproducibility (intraclass correlation >0.9), and the system was able to identify progression of capsular opacity over a 2-year period with a mean increase of 15.8% in progressors versus an increase of 0.6% in nonprogressors (P < 0.05).

CONCLUSIONS

Digital retroillumination images of the posterior capsule can be obtained reliably, and automated analyses correlate well with clinical assessment. The system presented here uses commercially available instruments and software, and it is practical for use in longitudinal studies of posterior capsule opacification. It is reliable, easy to use, and can detect small changes in the percentage area covered by posterior capsule opacification over time.

Using the measure of processes of care with parents of children hospitalized for head injury

Despite recommendations that rehabilitation programs adopt family/patient satisfaction as an outcome measure, few studies have addressed satisfaction with services for children with head injury. This report describes our use of the Measure of Processes of Care (MPOC) to document the perceptions of care of parents whose children were hospitalized with a head injury and to compare parental perceptions of care with those of the service providers (n = 16). The MPOC is a self-administered questionnaire consisting of 56 items, each of which is included in one of five care-giving scales: (1) enabling and partnership; (2) providing general information; (3) providing specific information about the child; (4) coordinated and comprehensive care; (5) respectful and supportive care. The MPOC was mailed to parents of children with a head injury who were consecutively admitted to a pediatric trauma center during a 5-mo period. The results, based on the responses of 73 parents (response rate, 59.3%), revealed that the needs of these parents are being met to varying degrees. Mean scores for the five scales ranged from 4.6 to 6.4 and from 5.9 to 6.6 for parents and providers, respectively. Significant differences between the groups were found for two scales: providing general and specific information. Because of the low percentage of valid responses for three of the five scales, the MPOC appears to be an inappropriate tool for use with parents of children with mild head injury (89%) in the acute care setting. The MPOC, however, is applicable for parents of children who are more severely injured (e.g., average hospital stay, 9 days) and is informative for rehabilitation service providers.

Racial differences in the prevalence of age-related macular degeneration: the Baltimore Eye Survey

OBJECTIVE

To determine the prevalence of age-related macular degeneration (AMD) and signs of age-related maculopathy in a population-based sample of blacks and whites 40 years of age or older from East Baltimore.

DESIGN

Cross-sectional population-based study.

PARTICIPANTS

A total of 5308 black and white subjects received a screening eye examination that included fundus photography.

MAIN OUTCOME MEASURES

Stereoscopic color fundus photographs were graded for the presence and severity of drusen, pigmentary abnormalities, geographic atrophy, and choroidal neovascularization in the macula.

RESULTS

Drusen > or = 64 microm were identified in about 20% of individuals in both groups, but large drusen (>125 microm) were more common among older whites (15% for whites versus 9% for blacks over 70). Pigmentary abnormalities were also more common among older whites (7.9% for whites versus 0.4% for blacks over 70). Age-related macular degeneration was more prevalent among whites than blacks. The prevalence of AMD was 2.1 % among whites over 70 years of age. No cases of AMD were detected among 243 black subjects in this age group. Logistic regression adjusting for age, sex and smoking (current, former, or never) detected an odds ratio of 4.4 (95% confidence interval: 1.5-12.4) for whites with AMD compared with blacks.

CONCLUSION

Although drusen are common in both blacks and whites over the age of 40, more severe forms of age-related maculopathy and late AMD are more prevalent in older whites.

Two kinesin light chain genes in mice. Identification and characterization of the encoded proteins

Native kinesin consists of two light chains and two heavy chains in a 1:1 stoichiometric ratio. To date, only one gene for kinesin light chain has been characterized, while a second gene was identified in a genomic sequencing study but not analyzed biochemically. Here we describe new genes encoding kinesin light chains in mouse. One of these light chains is neuronally enriched, while another shows ubiquitous expression. The presence of multiple kinesin light chain genes in mice is especially interesting, since there are two kinesin heavy chain genes in humans (Niclas, J., Navone, F., Hom-Booher, N., and Vale, R. D. (1994) Neuron 12, 1059-1072). To assess the selectivity of kinesin light chain interaction with the heavy chains, we performed immunoprecipitation experiments. The data suggested that the light chains form homodimers with no specificity in their interaction with the two heavy chains. Immunofluorescence and biochemical subfractionation suggested differences in the subcellular localization of the two kinesin light chain gene products. Although both kinesin light chains are distributed throughout the central and peripheral nervous systems, there is enrichment of one in sciatic nerve axons, while the other shows elevated levels in olfactory bulb glomeruli. These results indicate that the mammalian nervous system contains multiple kinesin light chain gene products with potentially distinct functions.

Assessing disability in the patient with cataract

Significant progress has been made over the past decade in assessing the functional impact of cataract on patients. Several questionnaires have been shown to predict well the outcomes of cataract surgery. The following article highlights the most recent research in this area and reviews the progress that has been made in the past several years.

Holmium laser sclerostomy in glaucomatous eyes with prior surgery: 24-month results

BACKGROUND AND OBJECTIVE

To evaluate the effectiveness of holmium laser sclerostomy in glaucoma patients who have had prior intraocular surgery.

PATIENTS AND METHODS

The authors conducted a retrospective analysis of outcomes for 25 patients who underwent holmium laser sclerostomy from 1991 to 1993.

RESULTS

Postoperative success (defined as a drop in intraocular pressure of 30% and a final intraocular pressure of less than 22 mm Hg) at 24 months ranged from 36% to 52%, depending on criteria chosen for success. There were no major complications from the procedure.

CONCLUSIONS

Holmium laser sclerostomy can be successful in a highly select group of patients undergoing filtration procedures who have had prior intraocular surgery.

A 210-mumol dose of vitamin A provides more prolonged impact on vitamin A status than 105 mumol among preschool children

A randomized controlled clinical trial was conducted to determine the relative protection afforded by two large doses of vitamin A against subclinical vitamin A deficiency among 345 preschool children. At baseline, children either had or were at high risk of developing non-corneal xerophthalmia. Vitamin A status was assessed by the relative dose response (RDR) test, serum retinol concentration, and ocular examination before and 3 and 6 mo following one oral dose of 105 mumol or 210 mumol of vitamin A. At 3 and 6 mo, mean serum retinol concentration was significantly higher in the 210-mumol group than in the 105-mumol group. The proportion of children with a positive RDR did not differ between groups at 3 mo, but by 6 mo there were three times more children positive in the 105-mumol group. Most of the observed difference was confined to children with xerophthalmia at baseline. The relative benefit of the 210-mumol dose was related to baseline vitamin A status. The current World Health Organization recommended prophylactic dose of 210 mumol seems appropriate.

Safety of one 52-mumol (50,000 IU) oral dose of vitamin A administered to neonates

A placebo-controlled trial was carried out among 2067 Indonesian neonates to assess the safety of administering one oral 52-mumol (50,000 IU) dose of vitamin A. Infants were assessed for potential acute side-effects before and throughout 48 hours after the dose. The first 965 infants were examined by cranial ultrasound before and at 24 hours after dosing to rule out intracranial haemorrhage and determine the resistive index (RI) of the anterior cerebral artery using duplex Doppler. Groups were comparable at the baseline. A bulging fontanelle occurred in the control and vitamin A groups, respectively, among 2.7% and 4.6% of the infants at 24 hours, and 2.4% and 4.5% of the infants at 48 hours. The groups did not differ in any other sign or symptom assessed. No infant developed intracranial haemorrhage. Mean RI values were normal and not different between groups at baseline or at 24 hours. Mean RI fell during the 24 hours, as normally occurs; the mean decrease was nearly identical in the two groups. A bulging fontanelle was not associated with increased rates of any sign or symptom or with an increase in RI. The 52-mumol dose of oral vitamin A may cause a small increase in intracranial volume in a small proportion of infants, but no increase in intracranial pressure. Acute side-effects following this intervention were rare and mild.

An active tissue-specific enhancer and bound transcription factors existing in a precisely positioned nucleosomal array

Nucleosomes positioned over promoters are usually inhibitory to protein binding and activity. We analyzed at the nucleotide level of resolution the nucleosomal organization of a distal, liver-specific enhancer in various mouse tissues and found that the enhancer exists in an array of three precisely positioned nucleosomes only in liver chromatin, where the enhancer is active. In vivo footprinting reveals that essential transcription factor-binding sites are occupied on apparent nucleosome surfaces, in one case leading to a perturbed nucleosomal structure. A similar nucleosomal array is generated with an in vitro chromatin assembly system in which nucleosome positioning is dependent upon binding to the enhancer of proteins related to hepatocyte nuclear factor 3. We suggest that certain transcription factors can organize nucleosomal structures that define an active enhancer element.

Biomedical applications of NASA technology

Through the active transfer of technology, the Technology Utilization (TU) Program of the National Aeronautics and Space Administration (NASA) assists private companies, associations, and government agencies in using NASA's technological resources effectively to improve U.S. economic competitiveness and to provide societal benefit. This article discusses several examples of how aerospace technology has been adapted to solve health care problems.

Pseudallescheria boydii keratomycosis in a horse

The fungal organism Pseudallescheria boydii was isolated from the cornea of a Quarter Horse with ulcerative keratitis. Despite aggressive hourly medication through a subpalpebral lavage system, with drugs including miconazole and natamycin, the cornea developed a stromal abscess. Orbital exenteration was performed after 3 weeks. The fungal isolate was later determined to be resistant to all 8 antifungal drugs tested. Microscopic examination of the cornea revealed fungal hyphae throughout the corneal stroma and penetrating the Descemet membrane. Pseudallescheria boydii has not been implicated previously as a cause of keratomycosis in horses or in other domestic animals, although cases in human beings have been described.

The value of serum antimicrosomal antibody testing in screening for symptomatic postpartum thyroid dysfunction

We investigated the value of a screening program for postpartum thyroiditis in a heterogeneous American population and used serum antithyroid antibodies to identify postpartum women at risk. Blood was drawn from 1034 consecutive women on their second postpartum day and tested for antimicrosomal and antithyroglobulin antibodies by hemagglutination. Seventy-two women (7.0%) were seropositive for antimicrosomal antibodies, but only seven (0.7%) had antithyroglobulin antibodies. There was a significant difference in the racial prevalence of antimicrosomal antibodies, with seropositivity in 52 of 588 white women (8.8%) versus nine of 367 black women (2.5%; p less than 0.001). Thirty-four of 51 (67%) antimicrosomal seropositive women followed at least 6 months post partum developed biochemical thyroid dysfunction and 20 of these patients required treatment for hypothyroidism. The mean (+/- SEM) serum thyroxine and thyrotropin levels in these patients before treatment were 3.0 +/- 0.3 micrograms/dl (normal 6.1 to 12.3 micrograms/dl) and 77 +/- 17 mU/L (normal 0.3 to 4.0 mU/L), respectively. Psychologic interviews revealed a significant increase in impaired concentration, carelessness, depression, and total complaints when patients with postpartum hypothyroidism were compared with postpartum euthyroid women. Medical evidence now suggests that postpartum thyroiditis is a common event and causes significant symptoms in women who develop hypothyroidism. Therefore, we propose that serum antimicrosomal antibody testing of postpartum women provides a feasible cost-effective screening method of identifying women likely to suffer from this disease.

Age-related alterations in trimethoprim-sulfadiazine disposition following oral or parenteral administration in calves

Age-related changes in the absorption and distribution patterns of trimethoprim/sulfadiazine were studied following oral or subcutaneous administration of 15 mg/kg of the drug combination in calves. Following oral administration, the time course of trimethoprim/sulfadiazine appearance and dissipation in serum, synovial fluid and urine was followed for periods up to 48 hours in calves one day, one week and six weeks of age. The profiles of drug appearance-disappearance in these body fluids were also determined after subcutaneous administration in seven week old calves. The peak serum and synovial fluid levels of trimethoprim/sulfadiazine achieved following oral administration were substantially lower with increasing maturation. In ruminating (six and seven week old) calves, subcutaneous or oral administration of the combination led to high serum levels of sulfadiazine but little or no serum trimethoprim was detected in animals at this age. The data indicate that, while therapeutic concentrations and optimum ratios of the drugs may be achieved for extended time periods in neonatal life, this dosage is unable to produce optimum serum and synovial fluid concentrations as the calves mature.