25-Gauge vitrectomy for paediatric vitreoretinal conditions.

UNLABELLED: This is a retrospective study of 56 eyes of 49 children undergoing vitrectomy with 25-gauge instrumentation. There were no cases of endophthalmitis, wound leaks or hypotony requiring treatment. A modified approach in which the conjunctiva and sclera is sutured was used for young babies requiring a pars plicata approach. OBJECTIVE: To evaluate the feasibility and safety of 25-gauge vitrectomy for various vitreoretinal indications in the paediatric population. METHODS: Consecutive patients aged 18 years or less undergoing vitrectomy for various vitreoretinal indications over a 5-year period were studied retrospectively. Two different surgical techniques were used: a modified 25-gauge approach in which the sclerotomies and conjunctiva were sutured as described previously for most children under the age of 1 year, and a transconjunctival 25-gauge approach for older children RESULTS: 56 eyes in 49 children (16 girls and 33 boys) were included. Intraoperative unplanned events or complications included: conversion to 20-gauge vitrectomy (four), conversion of one port to a 20-gauge sclerotomy (two), suspected lens damage (one) and intraoperative bleeding from a vascular ridge (one). Postoperative complications included cataract (five), rhegmatogenous retinal detachment (four) and vitreous haemorrhage (three). The four retinal detachments were either recurrent or occurred in eyes with complex ocular pathology and were not felt to be related to the surgical technique. There were no cases of postoperative hypotony requiring intervention, choroidal detachment, endophthalmitis or sclerotomy-related retinal breaks. CONCLUSIONS: 25-gauge vitreoretinal techniques can be used in various paediatric vitreoretinal conditions and facilitate easy access to small spaces in the paediatric eye. To avoid postoperative hypotony, a modified technique is recommended for younger babies in which the conjunctiva and sclera is sutured.

Combined 25- and 23-gauge surgery: a new sutureless vitrectomy technique.

The 25- and 23-gauge sutureless vitrectomy techniques decrease the surgical trauma and improve patients' postoperative comfort. The disadvantages of the 25-gauge system include pliable instrument and slower gel removal. The 23-gauge system provides faster speed of vitrectomy and the instruments have stiffer shafts, but it requires a larger incision. To circumvent some of these limitations, a new sutureless transconjunctival vitrectomy technique that combines 23- and 25-gauge cannulas and instruments was studied. Fifty-three patients underwent vitreoretinal surgery using two 25-gauge ports for the infusion and light probe and one 23-gauge port for the vitreous cutter and various instruments. No intraoperative or postoperative complications were noted and no cases required conversion to another technique.

The fellow eye of patients with phakic rhegmatogenous retinal detachment from atrophic holes of lattice degeneration without posterior vitreous detachment.

BACKGROUND: Primary phakic rhegmatogenous retinal detachment (RRD) without posterior vitreous detachment (PVD) represents a unique clinical entity that behaves differently from RRD associated with PVD. While previous studies have reported the long term findings in the fellow eye of patients with RRD and PVD, the outcome of the fellow eye of patients with RRD without PVD is not known. METHODS: Consecutive patients with RRD not associated with PVD were studied retrospectively. The authors evaluated the fellow eye for retinal detachment or other vision threatening pathology. RESULTS: 27 patients (mean age 32 years) were studied with follow up of between 9 and 326 months (mean 111 months). 24 (89%) were myopic. Bilateral retinal detachment occurred in eight patients (30%). On initial examination, 17 patients (63%) had retinal findings (including lattice degeneration, atrophic holes, and/or cystic retinal tufts) in the fellow eye that might predispose them to retinal detachment. 14 vision threatening events or diagnoses occurred (nine of which were rhegmatogenous in nature) in the fellow eye including eight retinal detachments, one traumatic PVD without retinal tears, one retinal tear after PVD, one diagnosis of pigmentary glaucoma needing trabeculectomy, two visually significant cataracts, and one diagnosis of chorioretinitis. 23 patients (85%) maintained visual acuity better than 20/50, with most retaining 20/20 vision in the fellow eye. CONCLUSIONS: Patients who experience RRD without PVD are at risk of developing vision threatening events in the contralateral eye and, as such, the fellow eye should be followed carefully.

Natural and anthropogenic processes that concentrate Mn in rural and urban environments of the lower Mississippi River delta.

This study evaluated natural processes and projected methylcyclopentadienyl manganese tricarbonyl fuel additives as sources of Mn accumulation in the environment. Data sets include fresh alluvium and sediments from the lower Mississippi River Delta and a soil metal survey of metropolitan New Orleans. The (1) railroad Mn, (2) industrial Mn, and (3) dynamic aquifer-stream transfer of Mn hypotheses were tested with the Mississippi River Delta data. Friction between Mn-rich steel wheels and rails contributes Mn (P = 0.017) to the environment, supporting (1). Sediment loads of Mn were similar (P = 0.77) upstream and downstream from the Louisiana industrial corridor, not supporting (2). The median Mn on the alluvium surface (59 mg/kg), in the aquifer (159 mg/kg), and in the riverbank aquifer discharge zone (513 mg/kg) support (3) as a mechanism for Mn enrichment of clay. The New Orleans soil metal survey data set shows a rural to urban increase of fourfold for Mn and three orders of magnitude for Pb. At 1999 U.S. highway fuel use, 8.3 mg of Mn per L would yield 5000 metric tons of Mn annually. If 13% of Mn were emitted, 650 tons of Mn would become aerosols annually, while 87% or 4350 tons would remain in engines. The 1999 toxic release inventory for Mn shows 370 tons as total emissions compared to the potential of 390 and 260 tons from vehicles, respectively, in urban and rural areas. A precautionary lesson from the use of Pb as a fuel additive is that the use of Mn as a fuel additive would be associated with an increased risk for neonates exceeding the estimated total tolerable daily intake of 2.1-16.5 micrograms Mn (especially in urban inner city environments) because neonates lack fully functional hepatic clearance for Mn.

Multiple metal contamination from house paints: consequences of power sanding and paint scraping in New Orleans.

Power sanding exterior paint is a common practice during repainting of old houses in New Orleans, Louisiana, that triggers lead poisoning and releases more than Pb. In this study we quantified the Pb, zinc, cadmium, manganese, nickel, copper, cobalt, chromium, and vanadium in exterior paint samples collected from New Orleans homes (n = 31). We used interior dust wipes to compare two exterior house-painting projects. House 1 was measured in response to the plight of a family after a paint contractor power sanded all exterior paint from the weatherboards. The Pb content (approximately 130,000 microg Pb/g) was first realized when the family pet died; the children were hospitalized, the family was displaced, and cleanup costs were high. To determine the quantity of dust generated by power sanding and the benefits of reducing Pb-contaminated dust, we tested a case study house (house 2) for Pb (approximately 90,000 microg/g) before the project was started; the house was then dry scraped and the paint chips were collected. Although the hazards of Pb-based paints are well known, there are other problems as well, because other toxic metals exist in old paints. If house 2 had been power sanded to bare wood like house 1, the repainting project would have released as dust about 7.4 kg Pb, 3.5 kg Zn, 9.7 g Cd, 14.8 g Cu, 8.8 g Mn, 1.5 g Ni, 5.4 g Co, 2.4 g Cr, and 0.3 g V. The total tolerable daily intake (TTDI) for a child under 6 years of age is 6 microg Pb from all sources. Converting 7.4 kg Pb to this scale is vexing--more than 1 billion (10(9)) times the TTDI. Also for perspective, the one-time release of 7.4 x 10(9) microg of Pb dust from sanding compares to 50 x 10(9) microg of Pb dust emitted annually per 0.1 mile (0.16 km) from street traffic during the peak use of leaded gasoline. In this paper, we broaden the discussion to include an array of metals in paint and underscore the need and possibilities for curtailing the release of metal dust.

PAH and metal mixtures in New Orleans soils and sediments.

The purpose of this study is to determine the degree of PAH contamination and the association of PAHs with inorganic substances in soils and sediments of New Orleans. Bonnet Carré Spillway (BCS) (n = 5) provides modern baseline data, while urban soil samples (CTY) (n = 27) and sediment samples from Bayou St. John (BSJ) (n = 11) provide experimental data for New Orleans. Soil samples were collected from the top 2.5 cm of the surface, air-dried, and sieved (2 mm). Sediments samples were collected with a Wildco-Ekman bottom dredge, air-dried and finely ground. Accelerated solvent extraction (ASE) was used to release PAHs from the samples and analysis was conducted with gas chromatography-mass spectrometry (GC-MS). Metals were extracted using a 5:1 ratio of 1 mol/L nitric acid (room temperature) for soil and sediment samples, shaken for 2 h, centrifuged (1000 x g for 15 min) and filtered. Metal analysis was done by inductively coupled plasma-atomic emission spectrometry (ICP-AES). Mann-Whitney tests show PAH differences (P < 0.001). Ranking of total PAHs is, BSJ sediments (10.3 mg/kg) > CTY soils (3.7 mg/kg) > BCS alluvium (0.28 mg/kg). The sum of the metals are similar for BSJ sediments (698 mg/kg) and CTY soils (679 mg/kg) and significantly lower for BCS (189 mg/kg). Manganese of these samples is similar for each site. For paired samples, Pearson Product Moment Correlation tests reveal that many PAHs are strongly associated with each other at all locations. For BCS alluvium and BSJ sediments, total PAHs are not significantly associated with total metals. For CTY, most pairs of metals are significantly associated, and total soil PAHs are strongly associated with total soil metals (correlation 0.78, P = 4.9 x 10(-4)). The linear model, total soil PAH = 136.3 + 6.25 (total soil metals) forms the basis for a predicted PAH map of New Orleans. Previous empirical research demonstrates an association between soil lead and children's lead exposure. This study indicates that PAHs are part of the soil mixture of accumulated substances and by-products of industrial society that presents exposure potential in cities.

Quantities and associations of lead, zinc, cadmium, manganese, chromium, nickel, vanadium, and copper in fresh Mississippi delta alluvium and New Orleans alluvial soils.

The topic of this study is the effect of anthropogenic metals on the geochemical quality of urban soils. This is accomplished by comparing the metal contents and associations between two alluvial soils of the lower Mississippi River Delta, freshly deposited alluvial parent materials and alluvial soils collected from a nearby urban environment. Fresh alluvium samples (n = 97) were collected from the Bonnet Carré Spillway. The urban alluvial soil samples (n = 4026) were collected from New Orleans and stratified by census tracts (n = 286). The Spillway samples tend to have less Pb and Zn than generally noted for the baseline of natural soils. Except for Mn and V, Spillway alluvium contains significantly less metal than urban soils. For Spillway samples, the median metal content (in microg g(-1)) is 4.7 Pb, 11.1 Zn, 0.7 Cd, 164 Mn, 0.8 Cr, 3.9 Ni, 3.2 V, and 3.9 Cu. For urban soils, the median metal content (in microg g(-1)) is 120 Pb, 130 Zn, 3.2 Cd, 138 Mn, 2.1 Cr, 9.8 Ni, 3.8 V, and 12.7 Cu. Metal associations also differ between Spillway alluvium and urban alluvial soils. Fresh alluvium correlation coefficients between individual metals vary from 0.87 to 0.99 (P < 10(-13)) except for Cr which ranges from 0.57 to 0.68 (P < 10(-7)). The urban soil correlation coefficients for metals and the index value are 0.40-0.98. In urban soils, Pb, Zn, Cr, and Cu are dominant metals and highly associated, with a correlation coefficient ranging from 0.83 to 0.98 (P < 10(-25)). Their strong association justifies the use of GIS to map the integrated soil metal index (sum of the medians of metals by census tract) of New Orleans. Although also positively correlated (0.40-0.68, P < 10(-10)), Cd, Mn, Ni and V differ in their distribution in the city compared to Pb, Zn, Cr and Cu. Overall, significantly higher metal values occur in the inner city and lower values occur in outlying areas. The human health impact of the mixture of metals is not well understood. This study provides empirical data about the mixture and distribution of metals in New Orleans alluvial soils. Given common technical development, especially of traffic flows in cities, similar patterns of soil metals are expected for all US cities and probably international cities as well. Primary prevention of urban metal accumulations is necessary to enhance and sustain the development of urban culture.

The urban environment and children's health: soils as an integrator of lead, zinc, and cadmium in New Orleans, louisiana, U.S.A.

Soils are evaluated as a diagnostic tool of environmental conditions that influence health. The samples for this study are urban topsoil (0-2.5 cm depth) samples (n=4026) analyzed for Pb, Zn, and Cd by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The parent materials for New Orleans soils are derived from the Mississippi River, and alluvium from the Bonnet Carré Spillway (n=31) serve as control samples for this study. The urban samples were stratified by census tract (n=286). Blood Pb (BL) levels of children /=310 microgram g(-1) and <310 microgram g(-1)) for higher metal census tracts (HMCTs) and lower metal census tracts (LMCTs), respectively, represents median BL exposures above and below 9 microgram dL(-1). HMCTs and LMCTs were characterized by demographic and socioeconomic data. HMCTs are more likely (P=4. 5x10(-6)) inhabited by Blacks than by Whites. Of 13,803 children

Associations between soil lead and childhood blood lead in urban New Orleans and rural Lafourche Parish of Louisiana.

This study evaluates associations between soil lead concentrations (SPb), age of housing, and blood lead levels (BPb) of children in metropolitan New Orleans and Lafourche Parish, Louisiana. The database includes over 2,600 SPb and 6,000 BPb samples paired by their median values and pre-1940 housing percentages for 172 census tracts. Associations were evaluated with Fisher's exact test and Spearman's rho test and modeled with the least sum of absolute deviations regression. Census tracts with low SPb are associated with new housing, but census tracts with high SPb are evenly split between old and new housing [Fisher's exact test, p = 8.60 X 10(-13) for the percentage of housing built before 1940 (percent pre-1940 housing) versus SPb]. The p-value for SPb versus BPb is 12 orders of magnitude stronger than the p-value for percent pre-1940 housing versus BPb. Census tracts with low BPb are associated with new housing, but census tracts with high BPb are split evenly between old and new housing (Fisher's exact test, p = 1. 67 X 10(-12) for percent pre-1940 housing versus BPb). Census tracts with high SPb are associated with high BPb and census tracts with low SPb are associated with low BPb (Fisher's exact test, p = 3.18 X 10(-24) for BPb versus SPb). The Spearman's rho test of the association of SPb and BPb in Orleans and Lafourche Parishes yielded a p-value of 6.12 X 10(-24). The least sum of absolute deviations regression model of the data is BPb = 1. 845 + 0.7215 (SPb)0.4. A comparison of the modeled BPb versus observed BPb has an r(2) of 0.552 and a p-value of 2.83 X 10(-23) that this relation was due to chance. If blood lead in children is more closely associated to soil lead than to the age of housing, then primary lead prevention should also include soil lead.

Blend uniformity analysis: validation and in-process testing. Technical Report No. 25. PDA (Parenteral Drug association).

One of the most challenging problems confronting oral solid dosage form manufacturers today is the difficulty in applying scientifically valid methods to blend uniformity validation. The Wolin decision in U.S. v. Barr Laboratories caused the FDA to reexamine and modify its policies on blend uniformity and sampling techniques. The resulting policies are predicated on the assumption that current technology provides a means to consistently collect minute representative samples from much larger static powder blends. A comprehensive review of the scientific literature indicates that current sampling technology is plagued by a propensity for sampling bias. This limitation is particularly troublesome to the pharmaceutical industry which must then hold these samples to very high standards. In response to these concerns the PDA Solid Dosage Process Validation Committee has reviewed approaches to blend uniformity analysis. This technical report provides: a method to determine the appropriate sample size for each product, a holistic approach for establishing meaningful acceptance criteria, a discussion on the use of proper analytical techniques and recommendations for conducting investigations for out-of-specification results.

Automated lamellar keratomileusis in situ for myopia.

BACKGROUND: Keratomileusis in situ, particularly automated lamellar keratoplasty, is a commonly performed technique of keratomileusis in the United States. METHODS: A single center consecutive series of 152 eyes undergoing keratomileusis in situ for myopia was analyzed. Spherical equivalent refractions were compared before and after surgery. The standard nomogram supplied with the automatic corneal shaper (Chiron Vision Corp, Irvine, Calif) was used. The mean of preoperative myopia treated was -9.30 +/- 3.10 diopters (D) (range, -5.12 to -22.75 D). RESULTS: Of the 144 eyes with 1 month follow up, 30 (21%) were within 0.50 D of the planned correction at 1 month, 54 (38%) were within 1.00 D, and 97 (67%) were within 2.00 D. At 6 or more months follow up, 51 of 68 eyes (75%) achieved uncorrected visual acuity of 20/40 or better and 13 of 68 (19%) 20/20 or better when eyes with macular degeneration and amblyopia were removed. Forty-six of 78 eyes (59%) with 6 months or greater follow up required retreatment procedures to correct residual myopia or astigmatism. Multiple regression analysis explained 40% of the variation between attempted correction and postoperative results. An overall 5% shift of refraction in the myopic direction occurred between 1 and 6 months. Of the 110 eyes with both 1- and 3-month examinations, the spherical equivalent refraction changed between these time intervals by 1.00 D or more in 54 (49%) eyes; and 11 (31%) eyes changed by 1.00 D or more between the 3- and 6-month examinations. Although 6% of eyes lost 2 or more lines of spectacle-corrected visual acuity, 11% gained 2 or more lines. CONCLUSION: Myopic keratomileusis in situ using the automated lamellar keratoplasty technique appears to be a safe and most effective procedure to reduce moderate to high myopia. However, the predictability of the procedure needs improvement.

Diisopropylfluorophosphate binding proteins (serine hydrolases) from normal and leukemic hematopoietic cells.

Normal and leukemic hematopoietic cell lysates were labeled with [3H]-diisopropylfluorosorophosphate ([3H]-DFP), an active site inhibitor of serine hydrolases. The labeled proteins in the lysates were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by counting of gel segments for radioactivity. The results indicate the presence of distinct [3H]-DFP binding patterns for different normal and leukemic hematopoietic cells; significantly lower labeling in normal or leukemic lymphoid cells compared to myeloid or monocytoid cells; lower labeling in acute myeloblastic leukemia (FAB-M1) as compared to acute myelomonocytic leukemia (FAB-M4), chronic myelomonocytic leukemia or monocytes and an increase in [3H]-DFP binding with cell maturation along granulocytic series. Thus, these patterns could be useful in discriminating acute lymphoblastic leukemia from myeloid/monocytoid types of leukemia and for following maturation of myeloid cells, and perhaps for studying functional or maturation defects in hematopoietic cells in other pathological conditions.

Indecainide: effects on arrhythmias, electrophysiology, and cardiovascular dynamics.

The cardiovascular pharmacology of indecainide, a new class I antiarrhythmic agent, was studied in intact animals. Arrhythmias produced by ouabain were converted to sinus rhythm by indecainide (100 micrograms/kg/min, i.v.) at 0.7 +/- 0.1 mg/kg and a corresponding plasma concentration of 1.7 +/- 0.2 micrograms/ml at the time of conversion. Infusion at a slower rate (20 micrograms/kg/min) converted to sinus rhythm at 0.4 +/- 0.1 mg/kg and 0.4 +/- 0.2 micrograms/ml plasma. Arrhythmias produced by prior (24 h) coronary artery occlusion were converted to 50% sinus rhythm by indecainide (100 micrograms/kg/min, i.v.) at 1.3 mg/kg. In conscious dogs, 6 mg/kg indecainide p.o. prolonged the PR and QRS intervals by 31 +/- 5 and 13 +/- 3%, respectively, at a corresponding plasma concentration of 2.8 +/- 0.5 micrograms/ml. His bundle studies revealed that the PR interval prolongation was due to an increase in both A-H and H-V intervals. In anesthetized dogs, indecainide (1-5 mg/kg, i.v.) decreased cardiac contractility, however, this effect was comparable to or less than that produced by other class I agents and was likely due to the Na+-channel-blocking activity of the drug. The autonomic effects of indecainide were slight and no effects were produced on peripheral hemodynamics, the QTc interval, or the central nervous system. It was concluded that indecainide is a potent class I antiarrhythmic agent that would appear to have only minimal propensity for producing adverse side effects in humans.