3D optical tomography in the presence of void regions

We present an investigation of the effect of a 3D non-scattering gap region on image reconstruction in diffuse optical tomography. The void gap is modelled by the Radiosity-Diffusion method and the inverse problem is solved using the adjoint field method. The case of a sphere with concentric spherical gap is used as an example.

Managed behavioral healthcare in the private sector

Employers, in their search for cost containment and quality improvement, have driven the development of the behavioral health managed care vendor. More specifically, the behavioral health carve-out is an innovation that was developed to respond to employer and, more recently, health plan needs. Now that the product has matured, it is increasingly being asked to justify its existence. Costs have certainly been maintained, but improvements in quality have not always been evident. The issues the authors address include, as cost pressures continue, can the industry deliver on its promise to improve care? Will it need to evolve to yet another level, with new or different features?

Aerobic intestinal flora of wild-caught African dwarf crocodiles Osteolaemus tetraspis

Intestinal contents were collected from wild-caught African dwarf crocodiles (Osteolaemus tetraspis) in 1993 and 1995 which were slaughtered at urban markets in the Congo Republic. The samples were kept frozen and brought back to Onderstepoort for aerobic culture. Out of 29 specimens, 33 species of bacteria and 20 species of fungi were isolated. The bacteria included three isolates of Salmonella and eight isolates of Escherichia coli, most of the latter being rough strains. The flora of individual specimens contained 1-5 bacterial and 0-5 fungal species. Neither Aeromonas hydrophila nor Edwardsiella tarda were isolated from any of the samples.

SNPing away at complex diseases: analysis of single-nucleotide polymorphisms around APOE in Alzheimer disease

There has been great interest in the prospects of using single-nucleotide polymorphisms (SNPs) in the search for complex disease genes, and several initiatives devoted to the identification and mapping of SNPs throughout the human genome are currently underway. However, actual data investigating the use of SNPs for identification of complex disease genes are scarce. To begin to look at issues surrounding the use of SNPs in complex disease studies, we have initiated a collaborative SNP mapping study around APOE, the well-established susceptibility gene for late-onset Alzheimer disease (AD). Sixty SNPs in a 1.5-Mb region surrounding APOE were genotyped in samples of unrelated cases of AD, in controls, and in families with AD. Standard tests were conducted to look for association of SNP alleles with AD, in cases and controls. We also used family-based association analyses, including recently developed methods to look for haplotype association. Evidence of association (P Collapse

Key Words Collapse

MESH Headings

• Age of Onset
• Alleles
• Alzheimer Disease/epidemiology
• Alzheimer Disease/genetics
• Apolipoproteins E/genetics
• Case-Control Studies
• Chromosome Mapping/methods
• Gene Frequency/genetics
• Genetic Predisposition to Disease/genetics
• Genotype
• Haplotypes/genetics
• Humans
• Linkage Disequilibrium/genetics
• Lod Score
• Middle Aged
• Models, Genetic
• Polymorphism, Single Nucleotide/genetics

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Grants

• 5 R01 NS31153-07 NINDS NIH HHS
• R01 NS031153 NINDS NIH HHS
• 2 P01 NS26630-11A1 NINDS NIH HHS
• 5 P50 AG05128-16 NIA NIH HHS
• Wellcome Trust
• P01 NS026630 NINDS NIH HHS
• P50 AG005128 NIA NIH HHS
• U24 AG021886 NIA NIH HHS

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Association of tamoxifen biliary excretion rate with prior tamoxifen exposure and increased mdr1b expression

ATPase transporter proteins are commonly found in the hepatocyte canalicular membrane. Some of these, in particular the multidrug resistance (mdr1b) gene, have been previously demonstrated to be inducible genes. In this study, we found that tamoxifen induced expression of the mdr1b gene in the liver up to 40-fold after 14 days' exposure to tamoxifen in the diet at a concentration of 420 ppm. As tamoxifen and its metabolites are primarily excreted into the bile, we investigated if the increased expression of mdr1b in the liver following tamoxifen exposure had any effect on its excretion in rats. We found that the excretion of tamoxifen and its metabolites into bile was increased from 8 +/- 1% to 51 +/- 18% (mean +/- SD) of an administered dose of 180 nmol/kg over a collection period of 3 hr in rats that had received tamoxifen (35 mg/kg) orally for 12 days (plus a 3-day rest) prior to the experiment. These data suggest that prolonged treatment with tamoxifen may result in lower serum and tumour concentrations, due to a self-mediated enhancement of excretion via mdr1b gene-encoded P-glycoprotein. This may have implications for other drugs sharing the same route of excretion and co-administered with tamoxifen.

An integrated map of human 6q22.3-q24 including a 3-Mb high-resolution BAC/PAC contig encompassing a QTL for fetal hemoglobin

Genetic studies have previously assigned a quantitative trait locus (QTL) for hemoglobin F and F cells to a region of approximately 4 Mb between the markers D6S408 and D6S292 on chromosome 6q23. An initial yeast artificial chromosome contig of 13 clones spanning this region was generated. Further linkage analysis of an extended kindred refined the candidate interval to 1-2 cM, and key recombination events now place the QTL within a region of <800 kb. We describe a high-resolution bacterial clone contig spanning 3 Mb covering this critical region. The map consists of 223 bacterial artificial chromosome (BAC) and 100 P1 artificial chromosome (PAC) clones ordered by sequence-tagged site (STS) content and restriction fragment fingerprinting with a minimum tiling path of 22 BACs and 1 PAC. A total of 194 STSs map to this interval of 3 Mb, giving an average marker resolution of approximately one per 15 kb. About half of the markers were novel and were isolated in the present study, including three CA repeats and 13 single nucleotide polymorphisms. Altogether 24 expressed sequence tags, 6 of which are unique genes, have been mapped to the contig.

Pentastomiasis in Bosc's monitor lizards (Varanus exanthematicus) caused by an undescribed Sambonia species

Two wild-caught Bosc's monitor lizards (Varanus exanthematicus) developed clinical signs of pentasomiasis approximately 3 yr after arrival in the United Kingdom. One died of chronic parasitic pneumonia associated with adult pentastomids of an undescribed Sambonia species. Eggs and immature pentastomids were also seen in histologic sections of the lungs and liver. The other animal was treated for pneumonia and for nodular inflammation of the larynx that restricted the diameter of the glottis. Fragments of pentastomid larvae were seen in a laryngeal biopsy, and the animal recovered after treatment with ivermectin and supportive therapy.

Analysis of association at single nucleotide polymorphisms in the APOE region

The discussion of the prospects of using a dense map of single nucleotide polymorphisms (SNPs) to identify disease genes with association analysis has been extensive. However, there is little empiric evidence to support this strategy. To begin to examine the practical issues surrounding this methodology, we identified 10 SNPs in the region immediately surrounding the apolipoprotein E locus (APOE), an established susceptibility gene for Alzheimer disease. Our goal was to examine patterns of allelic association to begin to investigate the question of whether APOE could have been identified using SNPs. Our strongest evidence of association was at the 2 SNPs immediately flanking APOE.

Psoriasis susceptibility locus in chromosome region 3q21 identified in patients from southwest Sweden

We have performed a pair-wise linkage study in the search for psoriasis susceptibility regions. A preliminary scan was performed on 20 families. In this set we obtained indications of linkage on chromosome 3q21. This region was further investigated using material from a total of 104 families (set 1B) resulting in a non-parametric linkage (NPL) of 1.77. The material was stratified in families whose parental origin is in southwest Sweden (set 1C). A maximum NPL value of 2.77 was obtained in this group. A transmission disequilibrium test (TDT) was performed on the stratified material (set 1C) and a significant P value of 0.005 was obtained, at marker D3S1269. The locus was confirmed with TDT in replicate material consisting of 148 families in which a single member was affected (P value 0.0007) at marker D3S1551. Thus, we have observed a significant P value using TDT in the vicinity of markers D3S1269/D3S1551, suggesting a novel psoriasis susceptibility region.

Indicator quality for multidisciplinary systems

In January 1998, a project studying the Unification of Indicator Quality for Assessment of Impact of Multidisciplinary Systems (UNIQUAIMS) began at IACR-Rothamsted. This three year European Union-funded project will examine the choice of indicators for the assessment of the sustainability and impact of multidisciplinary systems. The project links 27 developing country and European partners to clarify methods and rationalize indicators for assessing impact and sustainability in three priority areas: farming systems, ecosystems converted to agricultural use and degraded ecosystems. The results will be disseminated to national and regional agricultural research institutes, extension agents, research planners and policymakers to promote improved interdisciplinary, multidisciplinary and cross-sectorial management of natural resources. A strong socioeconomic component is involved. This paper describes the scientific and policy issues which led to the project and focuses upon the need to: clarify current methods of impact and sustainability assessment; identify key qualitative and quantitative indicators for both baseline and on-going studies and their relevance at different scales, allowing for the balance between standardization and responsiveness to local conditions; and establish sound guidelines for indicator collection procedures at all stages of research, from project conception through to impact and sustainability assessment.

Tricorrectional bunionectomy for hallux abducto valgus. A comprehensive outcome study

A longitudinal outcome study of the tricorrectional bunionectomy with AO screw fixation for the correction of hallux abducto valgus was undertaken involving 84 consecutive patients (121 feet) with a mean age of 48.4 years who underwent the procedure over a 6-month period. Preoperative and postoperative measurements of forefoot angles were calculated, with the following mean results obtained: intermetatarsal angle of 14.46 degrees corrected to 5.72 degrees, hallux abductus angle of 26.38 degrees corrected to 11.65 degrees, proximal articular set angle of 19.85 degrees corrected to 6.06 degrees, and tibial sesamoid position of 4.75 corrected to 1.87. The average time to return to athletic shoes was 12.63 days. Postoperative complications were minor, with no delayed unions, malunions, hematomas, bone infections, or hallux varus. Long-term follow-up (mean, 21.33 months) using the American Orthopaedic Foot and Ankle Society's objective Hallux Metatarsophalangeal-Interphalangeal Scale revealed an overall mean score of 88.94 points out of a possible 100. An excellent mean result of 95 points out of a possible 100 on the subjective patient rating scale was also reported.

Mutations associated with in vivo aflatoxin B1-induced carcinogenesis need not be present in the in vitro transformations by this toxin

Ingestion of aflatoxin B1 is implicated in the high incidence of human liver cancers in several developing countries. An association has been detected between human exposure to aflatoxins, and mutations in the third base of codon 249 of the p53 gene in hepatomas. In vitro experiments using human cell line cells and aflatoxin B1 have demonstrated the induction of p53 mutations in codon 249 and adjacent codons. It was therefore of interest to see if this correlation between the in vivo and in vitro situations held for other species. The present study examined a rat liver-derived cell line, transformed in vitro with aflatoxin B1, for the presence of mutations associated with in vivo aflatoxin-induced hepatocarcinogenesis. In an in vivo rodent model systems using the aflatoxin B1-sensitive male F344 rat, previous studies have shown that hepatocarcinogenesis is accompanied by significant incidences of codon 12 mutations in K-ras and codon 13 mutations in N-ras genes, but in contrast to the human, apparently not by mutations in codon 243 of the p53 gene (which corresponds to codon 249 in the human gene). In contrast to the situation in humans, mutation in the third base of codon 243 in the rat would not result in any changes in amino acid sequence, but mutations in codon 250, as seen in in vitro human systems, would be expressed in the rat p53 protein. In the present study, an immortalised, non-transformed liver epithelial cell line derived from a male F344 rat was transformed in vitro by aflatoxin B1 as demonstrated by tumour formation in nude mice. The transformation was dependent on metabolic activation of the aflatoxin B1. Transfection of DNA, extracted from these tumours, into NIH 3T3 fibroblasts conferred a stable, malignant transforming capacity. However, no mutations in codon 12 of the K-ras or codon 13 of the N-ras genes were detected in any of these tumours. These results indicate that in vitro transformation does not necessarily involve the same mutations, as those observed in vivo. Also, no mutations in codon 243 or adjacent codons of the p53 gene, paralleling those observed in the human cell line treated with aflatoxin B1, were detected. The results serve to emphasise the in vivo and in vitro variation in the oncogene activation in the same target organ or cell lines derived from that organ, even when using a single carcinogen activated by a known metabolic pathway.

WEBMAP: radiation hybrid mapping on the WWW

SUMMARY

A Java interface to radiation hybrid (RH) mapping software is described which enables users to build and interactively refine RH maps over the web.

AVAILABILITY

The Java applets described here are available on the internet at http://www.oxmol.com/biolib/webmap/.

A 4-Mb high-density single nucleotide polymorphism-based map around human APOE

Whole-genome association studies using single-nucleotide polymorphisms (SNPs) are the proposed method of choice for the identification of loci associated with complex diseases. In this report, we address the feasibility of generating high-density SNP maps (with <100-kb spacing). As a pilot study, we concentrated on a 4-Mb region around the human APOE locus on chromosome 19. We compared the efficiency of SNP detection using YAC-based versus BAC/PAC-based maps, sequencing individual DNAs versus a pooled DNA sample, and we evaluated three different software applications for polymorphism detection. A total of 121 SNPs (25 in coding regions) were identified. The frequency of SNP detection was 1 SNP/1.1 kb of genomic sequence. From APOE to CALM3 (approximately 2 Mb), the average marker spacing was approximately 30 kb. Fifty-one SNPs were genotyped in five populations, and 10 SNPs showed an allele frequency differential greater than 0.5 between populations. Our results demonstrated that high-density SNP maps can be efficiently generated using existing technologies and that a genome-wide map with 60,000-100,000 SNPs is achievable in a reasonable time frame.

Use of the BacT/Alert blood culture system for culture of sterile body fluids other than blood

Studies have demonstrated that large-volume culture methods for sterile body fluids other than blood increase recovery compared to traditional plated-medium methods. BacT/Alert is a fully automated blood culture system for detecting bacteremia and fungemia. In this study, we compared culture in BacT/Alert standard aerobic and anaerobic bottles, BacT/Alert FAN aerobic and FAN anaerobic bottles, and culture on routine media for six specimen types, i.e., continuous ambulatory peritoneal dialysate (CAPD), peritoneal, amniotic, pericardial, synovial, and pleural fluids. Specimen volumes were divided equally among the three arms of the study. A total of 1,157 specimens were tested, with 227 significant isolates recovered from 193 specimens. Recovery by method was as follows: standard bottles, 186 of 227 (82%); FAN bottles, 217 of 227 (96%); and routine culture, 184 of 227 (81%). The FAN bottles recovered significantly more gram-positive cocci (P < 0.001), Staphylococcus aureus (P = 0.003), coagulase-negative staphylococci (P = 0.008), gram-negative bacilli (P < 0.001), Enterobacteriaceae (P = 0.005), and total organisms (P < 0.001) than the routine culture. There were no significant differences in recovery between the standard bottles and the routine culture. The FAN aerobic bottle recovered significantly more gram-positive cocci (P < 0.001), S. aureus isolates (P < 0.001), coagulase-negative staphyococci (P = 0.003), and total organisms (P < 0.001) than the standard aerobic bottle, while the FAN anaerobic bottle recovered significantly more gram-positive cocci (P < 0.001), S. aureus isolates (P < 0.001), Enterobacteriaceae (P = 0.03), and total organisms (P < 0.001) than the standard anaerobic bottle. For specific specimen types, significantly more isolates were recovered from the FAN bottles compared to the routine culture for synovial (P < 0.001) and CAPD (P = 0.004) fluids. Overall, the FAN bottles were superior in performance to both the standard bottles and the routine culture for detection of microorganisms from the types of sterile body fluids included in this study.

The in vitro development of the pentastomid Porocephalus crotali from the infective instar to the adult stage

The in vitro development of the pentastomid Porocephalus crotali from the infective, seventh (VII) instar, dissected from the tissues of rat intermediate hosts, to the adult male (X) and female (XI) instars, normally resident in the lung of rattlesnake definitive hosts, is described. The culture medium comprised washed human blood cells, resuspended in bovine serum (50:50, v/v), with 20% minimum essential medium and antibiotics. Two batches of approximately 100 pentastomids, maintained at a density of 2 worms/ml, were cultured in 500 ml bottles in an atmosphere of 5% CO2 in air at 28 degrees C. Culture bottles were rotated slowly on a Rollacell system and the medium was replenished every 2-3 days. Growth was monitored at various intervals by weighing worms, measuring cast cuticles with attached moulted hooks recovered from the medium, and by dissecting worms for measurements of various organ systems. Three moults separated the infective and adult male instar, whereas 4 moults were necessary in the case of females. In both cultures natural mortality was about 10% over a 160-day period, by which time 33-51% of females and 62-70% of males had reached the terminal instar. Some males attained full sexual maturity with seminal vesicles loaded with viable sperm: such males were indistinguishable from males recovered from naturally infected rattlesnakes. However, females never achieved full size, even after 200 days, and although copulation did not occur in vitro, some females became patent.

Tricorrectional osteotomy for the correction of late-stage hallux limitus/rigidus

The authors propose the use of the tricorrectional osteotomy for treatment of severe hallux limitus/rigidus as an alternative to joint-destructive procedures. A study of 19 patients with follow-up treatment ranges of 10 months to 6 years postoperatively was performed. Data were collected on preoperative and long-term postoperative x-rays, range of motion assessment, F-scan studies, and subjective patient questionnaires. High patient satisfaction along with increased range of motion, minimal complications, and an early return to activities make this an ideal procedure for grades II, III, and IV hallux limitus/rigidus.

In vitro activation of the human Harvey-ras proto-oncogene by aflatoxin B1

Activation of ras proto-oncogenes occurs frequently in vivo in chemically induced rodent tumours, including rat hepatomas induced by aflatoxin B1. This study examines the in vitro activation of a human ras gene by this mycotoxin. A plasmid containing the human Ha-ras proto-oncogene, together with a neomycin resistance gene (pECneo), was incubated in vitro with a microsomal system generating aflatoxin B1 8,9-epoxide. Subsequent transfection of the plasmid into mouse NIH 3T3 fibroblasts, followed by G418 selection and s.c. injection of surviving cells into immunodeficient mice demonstrated that the proto-oncogene had acquired transforming capacity. Although a single tumour resulted from similar treatment of incubated unconjugated plasmid, no tumours were produced by a secondary round of transfections using DNA from this tumour. Selective PCR amplification of the human Ha-ras gene in extracted tumour DNA followed by sequencing demonstrated the presence of G-->T transversions either at the first or middle base of codon 12 in tumours resulting from transfection with the aflatoxin-B1-modified pECneo plasmid, but this was not detected in the single tumour resulting from transfection with the unmodified plasmid. Thus, although a mutation in the Ha-ras gene has not been reported for human primary hepatomas occurring in aflatoxin-exposed populations, metabolically activated aflatoxin B1 is capable of mutating this proto-oncogene to its oncogenic form in vitro. No mutations were observed in codon 61. It appears that, in contrast to the frequently reported G-->T transversions in codon 249 of the p53 gene in primary hepatomas in aflatoxin-exposed humans, the failure to detect Ha-ras mutations in these tumours is not due to an inability of aflatoxin B1 to activate this proto-oncogene. The G-->T transversions observed in this study contrast with the most frequent aflatoxin B1 in vivo induced mutations, G-->A transitions in the rat Ki-ras gene. Possible mechanisms for these differences are discussed.

Intrinsic multidrug class 1 and 2 gene expression and localization in rat and human mammary tumors

P-glycoproteins (P-gp), the protein products of the multidrug resistant (mdr) genes, are often overexpressed in tumors that are resistant to chemotherapy. In this study, we measured intrinsic (preexisting) mdr1a, -1b, and -2 gene expression in N-nitroso-N-methylurea-induced rat mammary tumors. Using immunohistochemistry and in situ hybridization, we determined the localization of mdr1b mRNA and P-gp. We compared these results with a similar morphologic analysis of untreated human breast carcinomas. The predominantly expressed member of the mdr gene family in normal rat mammary tissue was mdr2. In rat mammary tumors, mdr2 expression was only inconsistently and slightly increased (1.4-fold on average). In contrast, expression of the class 1 genes (mdr1a and mdr1b) were consistently increased to a much greater extent. The average increase of mdr1b gene expression was greater than that of mdr1a (on average, 12.9 compared with 2.4, respectively). This indicated a differential regulation of these two closely related genes in these tumors. Immunostaining and in situ analysis showed that mdr mRNA and P-gp were expressed in a minority of neoplastic epithelial cells located in defined areas of the tumor, often on the interface of the neoplastic epithelium and stroma. Single epithelial cells that had invaded the stroma also expressed P-gp. In human breast carcinomas, the patterns of mdr mRNA and P-gp expression were similar to those in rat N-nitroso-N-methylurea-induced mammary tumors.