HLA- and genotype-based risk assessment model to identify infantile onset pompe disease patients at high-risk of developing significant anti-drug antibodies (ADA).

In Pompe disease, anti-drug antibodies (ADA) to acid alpha-glucosidase (GAA) enzyme replacement therapy contribute to early mortality. Assessing individual risk for ADA development is notoriously difficult in (CRIM-positive) patients expressing endogenous GAA. The individualized T cell epitope measure (iTEM) scoring method predicts patient-specific risk of developing ADA against therapeutic recombinant human GAA (rhGAA) using individualized HLA-binding predictions and GAA genotype. CRIM-negative patients were six times more likely to develop high ADA titers than CRIM-positive patients in this retrospective study, whereas patients with high GAA-iTEM scores were 50 times more likely to develop high ADA titers than patients with low GAA-iTEM scores. This approach identifies high-risk IOPD patients requiring immune tolerance induction therapy to prevent significant ADA response to rhGAA leading to a poor clinical outcome and can assess ADA risk in patients receiving replacement therapy for other enzyme or blood factor deficiency disorders.

The efficiency of CO2 sequestration via carbonate mineralization with simulated wastewaters of high salinity.

Salinity generally strongly affects the solubility of carbon dioxide in aqueous solution. This would seem to involve a reduction of the efficiency of the carbonate mineralization process with the objective to sequester this greenhouse gas. On the contrary, we demonstrate here that with a more concentrated solution of magnesium chloride, the residence time of CO(2) is enhanced in the aqueous medium because of a reduced tendency to produce CO(2(g)). Experiments intended to simulate more closely the Mg-rich wastewaters that are industrially available have been carried out using solutions differing in Mg concentration (7, 16, 32 g L(-1) Mg). A comparison of the efficiency of the CO(2) mineralization process among sets of experiments shows that the reduction of the efficiency, to about 65%, was lower than that expected, as the low degree of CO(2) degassing results in the enhanced availability of carbonic ions to react with Mg ions to form stable carbonate minerals over a longer time.

Medium-dose UVA1 phototherapy in localized scleroderma and its effect in CD34-positive dendritic cells.

BACKGROUND: UVA1 radiation seems to be effective in morphea. CD34+ dendritic cells are significantly decreased in lesional skin of morphea patients. OBJECTIVE: We evaluated the therapeutic effectiveness of medium-dose UVA1 phototherapy in localized scleroderma and its effect in the number of dermal CD34+ dendritic cells in skin biopsy specimens of these patients. METHOD: Patients were irradiated with UVA1 (30 J/cm(2)) 30 times. Dermal CD34+ dendritic cells were counted before and after therapy. RESULTS: There was clinical improvement after UVA1 irradiation. Dermal CD34+ dendritic cells significantly increased after UVA1 irradiation. CONCLUSION: Medium-dose UVA1 therapy is effective in the treatment of localized morphea. Effectiveness is associated with an increase in the number of CD34+ dendritic cells in the dermis.

Simplified 13C-urea breath test for detection of Helicobacter pylori infection.

OBJECTIVE: The U.S. standard 13C-urea breath test (13C-UBT) has proven to be extremely reliable but entails several complicated performance requirements and a test period of approximately 1 h. The aim of this study was to compare the standard 13C-UBT with a simplified version embodying modifications of test meal, duration of fasting, amount of 13C-urea, method of breath collection, and duration of test. METHODS: This was a randomized, three-way, crossover study of the standard U.S. 13C-UBT, which contains 125 mg of 13C-urea and a pudding test meal. The final breath sample is taken 30 min after urea ingestion. This test was compared with a formulation containing 75 mg of 13C-urea, a 2.5-g citric acid test meal (UBT-Lite), and a final breath sample taken by direct exhalation into tubes 15 min after urea ingestion. We also compared the effect of prior meals versus fasting on the test outcome with the UBT-Lite. RESULTS: A total of 259 subjects were enrolled in the trial, and 249 completed all three urea breath tests. There was excellent agreement between the three versions of the UBT with >98% of subjects having concordant results. Using predetermined criteria, there was substantial equivalence between the tests. Neither solid and/or liquid food up to 1 h before performing the UBT-Lite affected outcome. CONCLUSION: The UBT-Lite formulation of the 13C-UBT proved to be an improved version of the U.S. standard 13C-UBT offering less expensive ingredients, shorter test duration, and a simplified breath test collection method, without sacrificing accuracy.

In vivo radioprotection of mouse brain endothelial cells by Hoechst 33342.

Radiation-induced loss of mouse brain endothelial cells has been examined in mice given an intravenous injection of the DNA-binding radioprotector Hoechst 33342 (80 mg kg-1). At the time of irradiation, 10 min after injection, Hoechst fluorescence in the brain was confined to the endothelial cells. Endothelial cell density was measured using a histochemical fluorescence technique that had been used previously to monitor post-irradiation changes in endothelial cell density in rat brain, in which it was shown that a sensitive subpopulation comprising about 15% of the endothelial cells was lost within 24 h of radiation exposure. The present study shows a similar dose-response for the control mice, with depletion of the sensitive subpopulation to 85% being almost complete after a dose of 2.5 Gy gamma-rays. However, in mice irradiated 10 min after Hoechst 33342 administration, doses between 12 Gy and 20 Gy were required to ablate these cells. The kinetics of cell loss and the rather large dose modification factor suggests that Hoechst 33342 may be suppressing an apoptotic response in this subpopulation. Whatever the mechanism involved, Hoechst 33342 clearly provides substantial protection against early radiation-induced endothelial cell loss. Further studies are necessary to determine the extent to which this initial protection translates into an improved long-term survival of the "protected" cells and, especially, to see whether this endothelial cell protection can ameliorate the later consequences of central nervous system irradiation, namely necrosis and paralysis.

Foundational model of neuroanatomy: implications for the Human Brain Project.

In order to meet the need for a controlled terminology in neuroinformatics, we have integrated the extensive terminology of NeuroNames into the Foundational Model of anatomy. We illustrate the application of foundational principles for the establishment of an inheritance hierarchy, which accommodates anatomical attributes of neuroanatomical concepts and provides the foundation to which other information may be linked.

Server-based approach to web visualization of integrated 3-D medical image data.

Although computer processing power and network bandwidth are rapidly increasing, the average desktop is still not able to rapidly process large datasets such as 3-D medical image volumes. We have therefore developed a server side approach to this problem, in which a high performance graphics server accepts commands from web clients to load, process and render 3-D image volumes and models. The renderings are saved as 2-D snapshots on the server, where they are uploaded and displayed on the client. User interactions with the graphic interface on the client side are translated into additional commands to manipulate the 3-D scene, after which the server re-renders the scene and sends a new image to the client. Example forms-based and Java-based clients are described for a brain mapping application, but the techniques should be applicable to multiple domains where 3-D medical image visualization is of interest.

Cytotoxicity of an 125I-labelled DNA ligand.

The subcellular distribution and cytotoxicity of a DNA-binding ligand [125I]-Hoechst 33258 following incubation of K562 cells with the drug was investigated. The ability of a radical scavenger, dimethyl sulphoxide, to protect cells from the 125I-decay induced cell death was also studied. Three different concentrations and specific activities of the drug were used to provide different ligand : DNA binding ratios. The results demonstrated a trend toward improved delivery of the ligand to the nucleus and to chromatin at higher ligand concentrations, with concomitant increased sensitivity to 125I-decay induced cytotoxicity and decreased protection by dimethyl sulphoxide. This correlation of radiobiological parameters with subcellular drug distribution is consistent with the classical dogma that attributes cytotoxicity to DNA double-stranded breakage in the vicinity of the site of decay, where the high LET nature of the damage confers minimal sensitivity to radical scavenging.

Multidisciplinary considerations for patients with cancer of the pancreas or biliary tract.

The past century has been nearly all of the growth in knowledge about the anatomy and pathophysiology associated with cancers of the pancreas and surrounding biliary structures. Through advances in imaging technology, endoscopic practice, improvement in surgical technique and perioperative care, anesthesia advances, and a better appreciation for the usefulness of adjuvant chemotherapy and radiation therapy, physicians can offer patients some hope for long-term survival and a better quality of life when they are faced with these devastating tumors. Although surgical intervention is the "last best hope" for these patients, advances in the nonoperative disciplines will be required for substantial further improvement in patient outcomes.

Iodine-125 decay in a synthetic oligodeoxynucleotide. I. Fragment size distribution and evaluation of breakage probability.

Lobachevsky, P. N. and Martin, R. F. Iodine-125 Decay in a Synthetic Oligodeoxynucleotide. I. Fragment Size Distribution and Evaluation of Breakage Probability. Incorporation of (125)I-dC into a defined location of a double-stranded oligodeoxynucleotide was used to investigate DNA breaks arising from decay of the Auger electron-emitting isotope. Samples of the oligodeoxynucleotide were also labeled with (32)P at either the 5' or 3' end of either the (125)I-dC-containing (so-called top) or opposite (bottom) strand and incubated in 20 mM phosphate buffer or the same buffer plus 2 M dimethylsulfoxide at 4 degrees C during 18-20 days. The (32)P-end-labeled fragments produced by (125)I decays were separated on denaturing polyacrylamide gels, and the (32)P activity in each fragment was determined by scintillation counting after elution of fragments from the gel. The relative fragment size distributions were then normalized on a per decay basis and converted to a distribution of single-strand break probabilities as a function of distance from the (125)I-dC. The results of three to five experiments for each of eight possible combinations of labels and incubation conditions are presented as a table showing the relative numbers of (32)P counts in different fragments as well as graphs of normalized fragment size distributions and probabilities of breakage. The average numbers of single-strand breaks per (125)I decay are 3. 3 and 3.7 in the top strand and 1.3 and 1.5 in the bottom strand with and without dimethylsulfoxide, respectively. Every (125)I decay event produces a break in the top strand, and breakage of the bottom strand occurs in 75-80% of the events. Thus a double-strand break is produced by (125)I decay with a probability of approximately 0.8.

Iodine-125 decay in a synthetic oligodeoxynucleotide. II. The role of auger electron irradiation compared to charge neutralization in DNA breakage.

Lobachevsky, P. N. and Martin, R. F. Iodine-125 Decay in a Synthetic Oligodeoxynucleotide. II. The Role of Auger Electron Irradiation Compared to Charge Neutralization in DNA Breakage. The dramatic chemical and biological effects of the decay of DNA-incorporated (125)I stem from two consequences of the Auger electron cascades associated with the decay of the isotope: high local deposition of radiation energy from short-range Auger electrons, and neutralization of the multiply charged tellurium atom. We have analyzed the extensive data reported in the companion paper (Radiat. Res. 153, 000-000, 2000), in which DNA breakage was measured after (125)I decay in a 41-bp oligoDNA. The experimental data collected under scavenging conditions (2 M dimethylsulfoxide) were deconvoluted into two components denoted as radiation and nonradiation, the former being attributed to energy deposition by Auger electrons. The contribution of the components was estimated by adopting various assumptions, the principal one being that DNA breakage due to the radiation mechanism is dependent on the distance between the decaying (125)I atom and the cleaved deoxyribosyl unit, while the nonradiation mechanism, associated with neutralization of the multiply charged tellurium atom, contributes equally at corresponding nucleotides starting from the (125)I-incorporating nucleotide. Comparison of the experimental data sets collected under scavenging and nonscavenging (without dimethylsulfoxide) conditions was used to estimate the radiation-scavengeable component. Our analysis showed that the nonradiation component plays the major role in causing breakage within 4-5 nucleotides from the site of (125)I incorporation and produces about 50% of all single-stranded breaks. This overall result is consistent with the relative amounts of energy associated with Auger electrons and the charged tellurium atom. However, the nonradiation component accounts for almost four times more breaks in the top strand, to which the (125)I is bound covalently, than in the bottom strand, thus suggesting an important role of covalent bonds in the energy transfer from the charged tellurium atom. The radiation component dominates at the distances beyond 8-9 nucleotides, and 36% of the radiation-induced breaks are scavengeable.

Structures of m-iodo Hoechst-DNA complexes in crystals with reduced solvent content: implications for minor groove binder drug design.

The DNA photosensitisers m-iodo Hoechst and m-iodo, p-methoxy Hoechst have been co-crystallised with the oligonucleotide d(CGCGAATTCGCG)(2)and their crystal structures determined. The crystals were then subjected to slow dehydration, which reduced their solvent contents from 40 (normal) to 30 (partially dehydrated) and then 20% (fully dehydrated) and caused a reduction in cell volume from 68,000 to 60,000 then 51,000 A(3). The dehydration resulted in a dramatic enhancement of diffraction resolution from approximately 2.6 to beyond 1.5 A. Crystal structures have also been determined for the partially and fully dehydrated states. The fully dehydrated crystals consist of an infinite polymeric network, in which neighbouring dodecamer duplexes are crosslinked through phosphate oxygens via direct bonding to bridging magnesium cations. This unique three-dimensional structure for DNA is described in detail in the following companion paper. The present paper details evidence from the sequence of crystal structures that the DNA is able to breathe locally, allowing the ligand to leave the minor groove, re-orient in the surrounding solvent medium and then re-enter the groove in a different orientation and location. The rearrangement of the minor groove binding ligands during the dehydration process mimics the binding behaviour of these ligands in solution and in vivo. We also present details of the DNA-ligand interactions that are consistent with a hydrogen atom ion mechanism for photocleavage of DNA.

Intermolecular interactions and water structure in a condensed phase B-DNA crystal.

By controlled dehydration, the unit cells of dodecamer DNA-drug crystals have been shrunk from 68,000 (normal state) to 60,000 (partially dehydrated intermediate state) to 51,000 A(3) (fully dehydrated state), beyond which no further solvent loss occurs. The total solvent content in the normal crystals is approximately 40% by volume, reducing to approximately 20% in the fully dehydrated phase. The 25% reduction in cell volume induced a dramatic enhancement in the resolution of the X-ray diffraction data (from 2. 6 to beyond 1.5 A). We have determined the structures of the normal, partially dehydrated and fully dehydrated crystals. Details of the ligand binding have been presented in the preceding article. The present paper describes the unique features of the structure of the fully dehydrated phase. This structure was refined with 9,015 unique observed reflections to R = 14.9%, making it one of the most reliable models of B -form DNA available. The crystals exist as infinite polymeric networks, in which neighbouring dodecamer duplexes are crosslinked through phosphate oxygens via direct bonding to magnesium cations. The DNA is packed so tightly that there is essentially only a single layer of solvent between adjacent molecules. The details of the crystal packing, magnesium bridging, DNA hydration and DNA conformation are described and compared with other experimental evidence related to DNA condensation.

General deming regression for estimating systematic bias and its confidence interval in method-comparison studies.

BACKGROUND: Various forms of least-squares regression analyses are used to estimate average systematic error (bias) and its confidence interval in method-comparison studies. When assumptions that underlie a particular regression method are inappropriate for the data, errors in estimated statistics result. In this report, I present an improved method for regression analysis that is free from the usual simplifying assumptions and is generally applicable to linearly related method-comparison data. METHODS: Theoretical equations based on the Deming approach, further developed by physicists and extended herein, were applied to method-comparison data analysis. Monte Carlo simulations were used to demonstrate the validity of the new procedure and to compare its performance to ordinary linear regression (OLR) and simple Deming regression (SDR) procedures. RESULTS: Simulation studies included three types of data commonly encountered in method-comparison studies: (a) constant within-method SDs for both methods, (b) constant within-method CVs for both methods, and (c) neither SDs nor CVs constant for both methods. For all cases examined, OLR produced unreliable confidence intervals of the estimated bias. However, OLR point estimates of systematic bias were reliable when the correlation coefficient was >0.975. SDR produced reliable estimates of systematic bias for all cases studied, but the confidence intervals of systematic bias were unreliable when SDs of methods varied as a function of analyte concentration. CONCLUSION: Only iteratively reweighted general Deming regression produced statistically unbiased estimates of systematic bias and reliable confidence intervals of bias for all cases.

The IHS dental program--a historical perspective.

The federal government provides health services for American Indians and Alaska Natives based on treaties with tribes, legislation, and executive orders. These services began in the late 1700s, when they were the responsibility of the Department of War. This responsibility was later transferred to the Bureau of Indian Affairs and in 1955 the Indian Health Service was established within the United States Public Health Service. This paper describes the development and mission of the Indian Health Service dental program. During the 1950s, Public Health Service officers were assigned to the dental program, dental assistant training centers were established, and clinical prevention programs were implemented. Increased dentist recruitment, the implementation of four-handed dentistry, and the development of an automated information system were the highlights of the 1960s. Considerable effort was placed on work force development during the 1970s, while expansions of both treatment and prevention services were the highlights of the 1980s. Unfortunately, decreases in administrative staffing and a decline in clinical services have been noted during the last decade. The main reasons for the decline were initiatives to reduce the size of federal government and inability to recruit and retain dentists in clinical positions. Also, many tribes have elected to manage their own programs and have requested and received their share of IHS administrative funds to use in their programs. Recent pay and budget legislation along with changes in program management should reverse this trend.

Tooth loss and need for extractions in American Indian and Alaska Native dental patients.

OBJECTIVE: This article reports results of the 1991 Indian Health Service Patient Oral Health Survey in the areas of tooth loss and need for tooth extraction. METHODS: The survey examined a sample of American Indian and Alaska Native dental patients. Tooth loss and need for tooth extraction are explored for a total of 12,349 individuals aged 18 years and older. RESULTS: Complete tooth loss in patients aged 35 years and older was 11 percent; in patients aged 65 years and older, it was 42 percent. The mean number of remaining teeth in dentate patients aged 35 years and older was 20.7; the mean number of remaining teeth decreased in each older age group. Partial and complete tooth loss were more severe in diabetic patients. In 35- to 44-year-old patients, only 20 percent had not lost at least one permanent tooth. The prevalence of tooth loss differs by geographic region. The percentage of dental patients with 20 or more teeth increased between 1984 and 1991. CONCLUSION: Tooth loss remains a substantial problem in American Indian and Alaska Native adult dental patients. This article presents results of an Indian Health Service (IHS) oral health survey conducted in 1991 of the American Indian and Alaska Native (Native American) population with respect to tooth loss. Limited comparisons of tooth loss observed in the 1991 patient survey are made to the 1984 patient survey.

Normalizing results of 13C-urea breath testing for CO2 production rates in children.

BACKGROUND: The 13C-urea breath test detects the presence of Helicobacter pylori from an enrichment of breath 13CO2, which, in turn, is critically dependent on the amount of dilution by endogenous CO2 production. The production of CO2 differs according to age (adults > children), sex (male > female) weight, and height. The cutoff value of 2.4 delta%(delta over baseline, DOB) for the 13C-urea breath test, defined in adults, does not take into account actual CO2 production. Therefore, this cutoff value (2.4 delta%) may or may not be appropriate for children. The purpose of this study was to determine a cutoff value that would provide accurate results in pediatric patients, independent of their differences in anthropometric parameters. METHODS: Estimates of CO2 production were combined with DOB values to calculate the host-dependent urea hydrolysis rate. RESULTS: Calculated as urea hydrolysis rate, the cutoff range for adults was 10.4 to 10.9 microg/min. Individual ranges were concentric (men, 9.6-10.9 microg/min; women, 8.5-12.2 microg/min). Results in studies of 312 children show that a urea hydrolysis rate of more than 10 m microg/min may also be appropriate to predict H. pylori infection. CONCLUSION: Calculating 13C-urea breath test values as urea hydrolysis rate removes the effect of individual anthropometric differences on test outcome and provides a single cutoff value for pediatric patients of all ages.

Pulse radiolysis studies indicate that electron transfer is involved in radioprotection by Hoechst 33342 and methylproamine.

PURPOSE: The aim of the study was to obtain evidence to support the hypothesis that the radioprotection by DNA-binding bibenzimidazoles is due to reduction by the DNA-bound ligand of transient radiation-induced oxidizing species on DNA, by following oxidation of the ligand after pulse radiolysis. A second aim was to compare the activities of methylproamine and Hoechst 33342 in the pulse radiolysis system, with the view to seeking a correlation with radioprotective activity. METHODS: Solutions of deoxyguanosine or DNA, with or without Hoechst 33342 or methylproamine, and containing sodium selenate and tert-butanol were subjected to pulse radiolysis, and the oxidation of the ligand followed by time-resolved spectrophotometry. RESULTS: The initial pulse radiolysis experiments using deoxyguanosine (dG) established that pulse radiolysis of sodium selenate produces a transient oxidant SeO3*-, which oxidizes dG to a species (presumably dG*+), with spectral characteristics indistinguishable from those described in previous pulse radiolysis studies using Br2*- as the oxidant. The estimate obtained for the bimolecular rate constant (k2) for the reaction of the selenite radical with dG, was 1.2 x 10(9) M(-1) s(-1). The corresponding reaction of SeO3*- with DNA is much slower (k2 3 x 10(7) M(-1) s(-1)). Although unbound Hoechst 33342 is oxidized directly by SeO3*- (k2 2.3 x 10(9) M(-1) s(-1)), experiments with mixtures of Hoechst 33342 with an excess of dG (or DNA) indicated that ligand oxidation was mediated by dG*+ (or DNAoxid). For example, successive dilution of a DNA-Hoechst solution had little impact on the rate of ligand oxidation, consistent with an intramolecular rate-determining step. When the concentration of DNA was maintained at 1.0 mM DNA bp, increasing the concentration of the ligand resulted in a linear increase in the rate of oxidation; the increase being steeper for methylproamine than for Hoechst 33342. Investigation of the dependence of yield of oxidized ligand on ligand occupancy also indicated that the methylproamine was more active than Hoechst 33342, with the estimates for the range of electron transfer from the ligand to DNAoxid being 14 and 31 bp for Hoechst 33342 and methylproamine, respectively. CONCLUSIONS: At this stage we conclude that radioprotection by these DNA-binding ligands is mediated by electron transfer, and that the improved radioprotective activity of methylproamine may be attributable to the observed kinetic differences. However, further studies are required to confirm the correlation, and if it is sustained, pulse radiolysis could be useful in evaluating new analogues in an attempt to further improve the radioprotective properties of methylproamine, which already has considerable clinical potential.

Options and strategies for the management of choledocholithiasis.

The introduction of laparoscopic techniques for the management of biliary stone disease has expanded the therapeutic choices for surgeons confronted with choledocholithiasis. As new strategies emerge, the treatment of cholelithiasis and choledocholithiasis remains controversial. This paper discusses the options available for the treatment of common bile duct stones. Diagnostic and therapeutic algorithms are proposed. The treatment of these patients must be individualized, taking into consideration the condition of the patient, associated diseases, secondary complications of the gallstones, and the surgical expertise and resources of the institution.