A platform for experimental precision medicine: The extended BXD mouse family

The challenge of precision medicine is to model complex interactions among DNA variants, phenotypes, development, environments, and treatments. We address this challenge by expanding the BXD family of mice to 140 fully isogenic strains, creating a uniquely powerful model for precision medicine. This family segregates for 6 million common DNA variants-a level that exceeds many human populations. Because each member can be replicated, heritable traits can be mapped with high power and precision. Current BXD phenomes are unsurpassed in coverage and include much omics data and thousands of quantitative traits. BXDs can be extended by a single-generation cross to as many as 19,460 isogenic F1 progeny, and this extended BXD family is an effective platform for testing causal modeling and for predictive validation. BXDs are a unique core resource for the field of experimental precision medicine.

Testing a Paul trap through determining the evaporation rate of levitated single semi-volatile organic droplets

Rigorous knowledge of the optical fingerprint of droplets is imperative for the understanding of complex aerosol processes. Here, a Paul trap is operated to store single semi-volatile organic droplets in air. The droplets are illuminated with a green laser and the elastic scattering is collected on a CMOS camera. The setup provides excellent performance in terms of confinement and stability, allowing us to detect size changes of the order of few nanometres. The stability also allows us to measure vapour pressures with remarkable reproducibility. This approach supplies a robust method for the optical interrogation in the sub-micron range.

Full path single-shot imaging of femtosecond pulse collapse in air turbulence

In a single shot, we measure the full propagation path, including the evolution to pulse collapse, of a high power femtosecond laser pulse propagating in air. Our technique enables examination of the effect of parameters that fluctuate on a shot-to-shot basis, such as pulse energy, pulse duration, and air turbulence-induced refractive index perturbations. We find that even in lab air over relatively short propagation distances, turbulence plays a significant role in determining the location of pulse collapse.

Mouse Models for Immunology Research available from The Jackson Laboratory Repository

The Jackson Laboratory Repository (JAX) serves as a centralized facility for the development, distribution and cryopreservation of mouse models of human biology and disease. JAX distributes more than 10,500 strains to the scientific community, many with applications in immunology research, including mouse models for autoimmune disease, infectious disease, immunodeficient platforms for PDX studies, and multi-purpose “tool strains” (such as CRISPR cas9-expressing lines), recombinase expressing strains, as well as conditional and inducible expression lines.

One of our newest strains is a conditional knock-out (KO) of STING/MYPS, a pathogen sensor involved in the activation of IL6 and IFNb. Additions to our extensive set of interleukin alleles include a SMART-17A knock-in (KI) expressing human NGFR on IL17A expressing cells and a KI/KO of Il9-expressing iCre/EYFP. The latest reporter and cre-expressing strains include an inducible cre KO/KI to Lyz2, and a KI/KO strain with dual reporters of chemokine Ccr2RFP and Cx3cr1GFPactivity, and two strains expressing the INDIA apoptosis reporter, one with widespread conditional expression and the other with expression in germinal center B cells. KOMP mice, offered via the MMRRC portion of the JAX Mouse Repository, provide a growing number of targeted immunological mutations.

Donating a strain to the Repository fulfills NIH’s requirements for sharing mice. Researchers wishing to have mice considered for inclusion in the Repository are encouraged to submit strains: www.jax.org/donate-a-mouse.

This work is supported by NIH, HHMI and private foundations.

Mouse Models for Immunology Research available from The Jackson Laboratory Repository

The mouse continues to provide researchers a means by which to address complicated immunological questions. The emergence of disruptive genetic engineering technologies have proven to be very applicable to the mouse, spawning a new generation of promising preclinical models. To facilitate access to this flourishing resource, The Jackson Laboratory (JAX) Mouse Repository offers one of the largest sets of well-characterized, genetically engineered mutant mice. Hundreds of new strains are added annually to the collection.

Our newest strains include conditionally targeted interleukins, often combined with Cre recombinase and/or reporters. The conditional Il33 knock-out/in (KO/KI) carries an EGFP reporter, a KO/KI to the Il5 gene results in Il15-specific expression of tdTomato and humanized cre, a similar KO/KI to the Il22 gene results in tdTomato/cre expression in intestinal lymphoid tissues, and a KI to Il21 results in expression of Verde green (VFP). Another new strain expresses cre and GFP within peripheral CD8+ T cells.

MMRRC program mice include a suite of strains expressing and responding to influenza virus hemagglutinin (HA) neo-self antigen for the study of immune regulation, tolerance and autoimmunity. A Pad4 KO, exhibits absent histone deimination in neutrophils and a defective response to acute infection. KOMP mice, also offered via the MMRRC portion of the JAX Mouse Repository, provide a growing number of targeted immunological mutations. Donating a strain to the Repository fulfills NIH’s requirements for sharing mice. Researchers wishing to have mice considered for inclusion in the Repository are encouraged to submit strains: www.jax.org/donate-a-mouse.

This work is supported by NIH, HHMI and private foundations.

Mouse Models for Immunology Research available from The Jackson Laboratory Repository

The Jackson Laboratory Repository serves as a centralized facility for the development, distribution and cryopreservation of mouse models of human biology and disease. Hundreds of new strains are added annually to one of the largest collections of characterized mouse strains available.

Our newest strains carry genes associated with T lymphocyte regulation and development. T cells from the Fyb (ADAP) knockout (KO) exhibit impaired proliferation and TCR-mediated adhesion. T cells from the Cd27 KO have a diminished viral response and a delayed memory cell response. A conditional KO of Kdm6b (Jmjd3), a histone demethylase, results in altered T cell differentiation. Finally, conditional expression of an HA-tagged mutant human transcription factor, FOXO, is associated with regulatory T cell function.

Mice carrying the Ifnar1 (interferon αβ receptor 1) KO allele have a reduced immune response and increased susceptibility to viral infection. The Ifnar1 KO, combined with the Ifngr1 (interferon γ receptor 1) KO allele provide a model for Zika virus (and other viruses) pathogenesis.

New tool strains include two conditional GFP knockin reporters, one in Spic, a transcription factor expressed in macrophages, and the second in Ebf1, a transcription factor involved in B cell development. A knockin to Zbtb46, a zinc finger transcription factor, expresses Cre recombinase in classical dendritic cells.

Donating a strain to the Repository fulfills the NIH’s requirements for sharing mice. Researchers wishing to have strains considered for inclusion in the Repository are encouraged to submit their strains: www.jax.org/donate-a-mouse.

This work is supported by NIH, HHMI, and several private charitable foundations.

Mouse models for immunology research available from The Jackson Laboratory Repository

The Jackson Laboratory Repository serves as a centralized facility for the development, distribution and cryopreservation of mouse models of human biology and disease. Hundreds of new strains are added annually to one of the largest collections of characterized mouse strains available.

This poster presents our newest strains involving genes associated with adaptive immunity. The Pdcdl (programmed cell death 1 - PD1) knockout (KO) mice allow increased infiltration of inflammatory cells in several disease models. CC10-OVA transgenic mice direct OVA expression to lung epithelium; and a KO/KI mouse expresses tamoxifen-inducible cre under the control of the Cd19 promoter in B lymphocytes.

New mouse models with mutations in genes involved in the innate immune response include: Dectin-1 (Clec7a) KO mice, which exhibit increased sensitivity to fungal infection and a dysregulated chemokine response; GM-CSF (Csf2) KO mice with impaired phagocytosis, a lupus-like disorder and glomerulonephritis; mice with a KO in MPYS (Tmem173), a pattern recognition receptor that activates type 1 interferon; Ccr2gfp KI/KO mice used in tracking monocyte chemotaxis; a transgenic mouse model of hyperimmunoglobulin E syndrome that expresses modified Stat3; and a new addition to our extensive collection of interleukin mutants, Il1a, a new conditional KO/reporter allele that is produced by monocytes and macrophages.

Additionally, several Cas9-expressing lines, requiring only a specific single guide RNA to generate single or multiple simultaneous mutations, are available. These lines overcome the burden of packaging size limits.

Researchers are encouraged to deposit mice to the Repository: www.jax.org/donate-a-mouse.

Mouse models for immunology research available from the Jackson Laboratory Repository (HUM1P.318)

The Jackson Laboratory Repository serves as a centralized facility for the development, distribution and cryopreservation of mouse models of human biology and disease. Hundreds of new strains are added annually to one of the largest collections of characterized mouse strains available. This poster presents our newest knockout (KO) strains involving genes associated with cell-mediated and humoral immunity. Lag3 (lymphocyte activation 3) KO mice allow further characterization of Treg suppressive function. Pvr (CD155)-null mice carry a lacZ reporter and exhibit inefficient IgA/IgE responses in response to challenge. The loxP-flanked Bcl6 mice carry a conditional allele involved in the differentiation of CD4 T cells into follicular Th cells. Two strains provide reporter/KO mutants of genes involved in the complement pathway, C1qa and Cfb. In addition, the hematopoietic cytokine, Il3, joins our extensive collection of interleukin mutants. New research tools include the following: a strain with EGFP and cre expression from the Zbtb16 (PLZF) promoter, in which expression is directed to the NKT cell lineage; a cre knockin (KI) into the Cx3cr1 promoter region for fate-mapping studies of the monocyte/macrophage compartment; and a ROSA26 KI that features a two-color fluorescent Cre reporter (widespread red fluorescence prior to cre exposure and localized green fluorescence following cre exposure). Researchers are encouraged to deposit mice to the Repository: www.jax.org/donate-a-mouse.

Abstract B43: Mouse models for cancer research available from The Jackson Laboratory Repository

The Jackson Laboratory Repository serves as a centralized facility for the development, rederivation, distribution and cryopreservation of mouse models of human biology and disease. Hundreds of new strains are added annually to one of the largest collections of characterized mouse strains available to the international biomedical research community. This poster features a wide range of models ideally suited to studies related to cellular cancers, solid tumors, and conditional/inducible cancer-associated gene expression.

To highlight transplantation/engraftment and “humanized” mouse research, several mouse lines with improved engraftment and specialized human cell colonization are described. Such animals complement our NSG (NOD.Cg-Prkdcscid Il2rgtm1Wjl) and NRG (NOD.Cg-Rag1tm1Mom Il2rgtm1Wjl) mice as ideal tools for engraftment with a wide range of malignant or non-malignant human or mouse tissues or cell lines. Several of the NSG or NRG models are combined with human HLA genes, including: Tg(HLA-DRB1)31Dmz, Tg(HLA-DRA,HLA-DRB1*0401)39-2Kito, Tg(HLA-DRA*0101,HLA-DRB1*0101)1Dmz, Tg(HLA-A/H2-D/B2M)1Dvs and Tg(HLA-A2.1)1Enge. NSG is also combined with transgenes expressing human cytokines such as Tg(CMV-IL3,CSF2,KITLG)1Eav and Tg(PGK1-KITLG*220)441Daw.

Several new knockout and floxed strains carry genes associated with tumor suppression. Septin 4 (Sept4)-null mice exhibit an increased incidence of hematopoietic malignancies. Tip30 (or Htatip2) knockout mice develop carcinoma and/or sarcoma in a variety of tissues. Floxed genes associated with tumor suppression include Ets2 and Fbxw7. Ets2 (E26 avian leukemia oncogene 2) functions in tumor repressive and tumor supportive roles in different types of cancer and epithelial tumor microenvironments. The ubiquitin ligase, Fbwx7, is involved in targeting the cell cycle regulators c-Myc and NOTCH1 for proteasomal degradation.

Other recent additions include the Cre/Tet-Off microRNA (Mir21 and Mir155) strains under the control of the widely expressed ROSA26 promoter. In this Cre/Tet-Off system, combination with a tissue-specific Cre expressing strain removes a STOP cassette allowing overexpression of the microRNA; doxycycline (dox) administration turns off expression. Overexpression of either mir-21LSL-Tetoff or mir-155LSltTa results in lymphomas, inhibition of expression results in tumor regression. Also notable are two transgenes expressing a tetO-MYC (myelocytomatosis oncogene) and a tetO-Tag (SV40 large T antigen). In double transgenic mice, TetO-MYC; Cebpb-tTA (liver-specific), withdrawal from dox results in invasive metastatic liver tumors. The c-Myc-EFGP mice have a fluorescent reporter knocked into the Myc oncogene; PRCre knockin mice express Cre recombinase in progesterone expressing cells and may be useful for studying progesterone-responsive cells/tissues. The Tet2f/f mouse provides a conditional (floxed) allele of the Tet2 oncogene for the creation of tissue-specific mutants. TET2 is associated with myeloid malignancies in humans.

The Jackson Laboratory Repository maintains a searchable online resource to find mice (JAX® Mice database: www.jaxmice.jax.org/query). Anyone wishing to donate their mouse strains for cryopreservation/distribution may submit them using our online submission form (www.jax.org/donate-a-mouse). The Jackson Laboratory Repository is supported through our NCI designated Cancer Center and other NIH mechanisms, The Howard Hughes Medical Institute, The Ellison Medical Foundation and several private charitable foundations.

Please stop by for a detailed list of recently added mouse strains for cancer research. Also visit our cancer research resources website at: www.jaxmice.jax.org/cancer.

Citation Format: Alicia Valenzuela, Cathleen M. Lutz, Stephen F. Rockwood, Michael Sasner, Leah Rae Donahue. Mouse models for cancer research available from The Jackson Laboratory Repository. [abstract]. In: Proceedings of the AACR Special Conference: The Translational Impact of Model Organisms in Cancer; Nov 5-8, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(11 Suppl):Abstract nr B43.

Mouse models for immunology research available from the Jackson Laboratory repository. (IRM9P.718)

The Jackson Laboratory Repository serves as a centralized facility for the development, rederivation, distribution and cryopreservation of mouse models of human biology and disease. Hundreds of strains are added annually to one of the largest collections of characterized mouse strains available to the biomedical research community. This poster presents new knockout (KO) strains carrying genes associated with T cells and antigen (Ag) presentation. Lcp2 (SLP-76)-null mice lack T cells and γδ-TCR+ cells. Psmb8 (LMP-7) KO mice exhibit impaired Ag presentation and reduced T cells. In Clec9a (DNGR-1) KO/GFP knock-in (KI) mice, cross-priming of CD8+ T cells against dead-cell-associated antigens is altered. Nlrp3-/- (cryopyrin) mice are useful for studying role of the inflammasome in immune responses. New floxed strains include Cxcl12, Csf1r and a floxed-stop ubiquitous Myc-driven human CD2 KI. Cxcl12 functions in lymphoid progenitor and hematopoietic SC maintenance. The cytokine, Csf1r, is associated with macrophage function. Other additions include: a tamoxifen-inducible KI of EGFP/cre/ERT into the Foxp3 locus, a transcription factor required for development and function of Treg cells; a Notch reporter with GFP expression directed to the Notch pathway; an RORgamma-driven cre transgene that directs expression to αβ T cells, immature thymocytes and lymphoid tissue inducer cells. To have your strain considered for inclusion in the Repository please visit www.jax.org/donate-a-mouse.

A major fish stranding caused by a natural hypoxic event in a shallow bay of the eastern South Pacific Ocean

A massive beaching and mortality of fishes occurred in Coliumo Bay, a shallow bay located along the coast of the eastern South Pacific Ocean on 3 January 2008. This stranding was a consequence of an abrupt decrease in the dissolved oxygen concentration throughout the whole water column, due to the effect of intense upwelling along the coast off central-southern Chile. The main objectives of this study were: (1) to characterize taxonomically and biologically the fish species assemblage present in this beaching; (2) to evaluate several physiological indicators for the condition of the beached species at the time of their death; and (3) to assess the possible cause-effect mechanisms involved in the fishes death and the changes that took place in the fish community throughout the time. In this beaching, 26 fish species were identified: 23 teleosts, one myxiniform and two elasmobranchs. Most beached specimens were juveniles. Haematological and histological evidence indicate that severe hypoxia that lasted for at least 48 h was the most plausible cause of death. The main conclusion of this study is that the presence of oxygen-poor equatorial sub-surface water in the shallow coastal zone due to intense regional-scale upwelling caused the fish stranding. Although the effect of the hypoxic event was severe for the fish assemblage of Coliumo Bay, the rapid recuperation observed suggests that hypoxic events at the local spatial scale can be buffered by migration processes from the fish community inhabiting close by areas non-affected by low oxygen conditions. The effect that severe hypoxic events may have on larger spatial scales remains unknown.

Abstract 4205: The Jackson Laboratory Repository: new mouse models of cancer

The Jackson Laboratory Repository serves as a centralized facility to import, develop, preserve, and distribute mouse models to the scientific community. More than 400 strains are added annually to one of the largest collection of characterized mouse strains available.

New models of increased tumor incidence at the Repository include three transgenic strains for studies of prostate tumorogenesis that use the rat probasin promoter, (Pbsn-ERG*) develops prostate neoplasia resulting from the expression of the ERG oncogene in prostate epithelial cells; a companion strain that expresses hepsin and GFP in prostate epithelial cells (Pbsn-Hpn,-GFP); a transgenic (Pbsn-IGF1*) that develops prostate hyperplasia; a B cell lymphoma transgenic model expressing the human T-cell leukemia/lymphoma 1 gene (Cd79b-TCL1A); a mouse with a targeted mutation in the kinase Plk3 that develops spontaneous tumors in multiple organs (lung, kidney, liver); a mouse with a targeted mutation in Xpc that exhibits increased susceptibility to radiation induced skin cancer and acetylaminofluorene-induced lung and liver cancers; and a targeted mutation in the tumor suppressor, Tnk1, that develops high rates of spontaneous tumors (lymphomas and carcinomas).

Other recently added mutants allow cancer research in different areas ranging from an amino acid substitution (S10A) in Cdkn1b (p27) that reduces susceptibility to induced lung tumors to new research tools, which include a tetracycline (tetO) regulated Erbb2 (TRE-Neu) transgenic strain that develops hyperplasia in tissues where Erbb2 is expressed when combined with a tTA/rtTA strain, and a transgenic mouse, which expresses human ERBB2 (HER2) in mammary gland and brain, displays tolerance to ERBB2 antigen and may be useful in testing ERBB2-based vaccines and immunotherapies.

Equally important are the Cre recombinase-expressing strains used in conjunction with these mutants. Most of the existing Cre strains have not been fully characterized and ‘ectopic’ expression of Cre recombinase can confound analysis of experimental results. The Repository has undertaken a project to comprehensively characterize Cre recombinase activity in embryonic and adult mouse tissues. Annotated images are being published on a dedicated website and submitted to MGI as part of a collaboration to develop a Cre stain database (http://www.creportal.org/). This information will allow users to make informed judgments about the suitability of a particular line for their experiments.

The Repository maintains a searchable on-line resource (www.jaxmice.jax.org/query). Researchers wishing to have strains considered for inclusion in the Repository are encouraged to submit their strains at: www.jax.org/grc/.

The Jackson Laboratory Repository is supported by the NCRR, The Howard Hughes Medical Institute, The Ellison Medical Foundation and donations from private charitable foundations.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4205.

Hemopoietic stem cell transplantation in refractory rheumatoid arthritis is not a contraindication for reconstructive surgery

Hemopoietic stem cell transplantation (HCST) is an experimental therapy that may produce prolonged remissions in patients with rheumatoid arthritis (RA) resistant to other treatments. Prosthetic articular replacement is often required in severe long-lasting disease. There is a well-founded concern regarding the feasibility and safety of reconstructive surgery after HSCT and as yet no published data on the subject. We report a patient with RA of 9 years' duration resistant to conventional treatments plus femoral head necrosis, who underwent prosthetic hip replacement with no post-surgical complications one year after HSCT, with a sustained response.

Association of NRAMP1 promoter gene polymorphism with the susceptibility and radiological severity of rheumatoid arthritis

The natural resistant-associated macrophage protein 1 (NRAMP1) has been proposed as a candidate gene for the susceptibility to autoimmune diseases. In this study, the possible role of the functional polymorphism located at the promoter region of NRAMP1 gene in the susceptibility and clinical outcome of rheumatoid arthritis (RA) was investigated. A total of 141 Spanish RA patients and 194 controls previously typed for HLA-DRB1* were genotyped for the NRAMP1 polymorphism. No significant differences in the distribution of frequencies among RA patients and controls were observed. Nevertheless, when patients and controls were stratified according to their HLA shared epitope (SE) status, an increase of 2/2 genotype among SE-negative (SE-) patients with respect to SE- controls was observed (23% vs 7%, OR = 3.74, 95% CI 1.31-10.72). In addition, the possible role of this polymorphism in the clinical course of RA was investigated in a subgroup of 82 patients who were prospectively followed during a mean of 9 years. After follow-up, an increase of patients with the homozygous 2/2 genotype was detected among those with severe small joint radiological involvement: 73% of patients 2/2 had a severe form in contrast to 37% of patients with the genotype 2/3 and 30% of patients bearing 3/3 OR = 5.45, 95% CI 1.14-34.24). In conclusion, NRAMP1 gene promoter polymorphism could influence the radiological severity of rheumatoid arthritis and disease susceptibility, particularly in individuals lacking HLA-linked risk factors.

Molecular epidemiology of a multiresistant Pseudomonas aeruginosa outbreak in a paediatric intensive care unit

After isolation of multiresistant (MR) Pseudomonas aeruginosa from 3 hospitalized patients in a paediatric intensive care unit (PICU), a prospective surveillance programme was established to detect infected and/or colonized patients in the hospital. Isolates were examined by means of outer membrane protein (OMP) profiles, serotyping and DNA genomic analysis using pulsed-field gel electrophoresis (PFGE). Fifty-five P. aeruginosa strains were isolated from 23 hospitalized patients during September and October 1997. The median hospital stay before isolation of P. aeruginosa was 8 d. PFGE demonstrated that the same clone infected 14 patients, 4 of whom were not hospitalized in the PICU. Susceptibility patterns and OMP profiles correlated with PFGE results in 37.8% and 36.4% of cases, respectively. Serotype O11 correlated with pattern A in 77% of cases and serotype O4 correlated with unrelated strains in 75% of cases but did not discriminate between outbreak and unrelated isolates. Extensive investigation of cultures failed to identify a reservoir of P. aeruginosa. PFGE was superior to OMP analysis and serotyping for discriminating between strains. The possible mode of acquisition for most of the patients infected with the same clone was cross-contamination.

Association of the CTLA4 3' untranslated region polymorphism with the susceptibility to rheumatoid arthritis

Cytotoxic T-lymphocyte antigen 4 (CTLA4) gene polymorphism located in the 3' untranslated region (UTR) was investigated in 141 Spanish patients (38 men and 103 women) with rheumatoid arthritis (RA) and in 194 ethnically-matched healthy controls. Twenty alleles having different numbers of (AT) repeats (from 7 to 32) were found in this population. (AT)7 and (AT)16 were the most frequent alleles, and accounted for almost two-thirds of the allelic frequency in the control population. Consequently, alleles were assigned as L (large: 16 or more AT repeats) or S (short: less than 16 AT repeats). When the L/S distribution in patients and controls were compared, an increase of L alleles was observed among patients (49.9% vs. 39.7%; p = 0.02; p(c) = 0.04, odds ratio [OR] = 1.46; 95% confidence interval [CI], 1.06-2.01). Hence, the frequency of S alleles was decreased among patients (51.1% vs. 60.3%; p = 0.02; p(c) = 0.04; OR = 0.69; 95%CI, 0.50-0.95). Moreover, a statistically significant decrease in the frequency of S/S individuals was observed among RA patients (27.7% versus 40.7%; p = 0.01; p(c) = 0.03; OR = 0.56; 95%CI, 0.34-0.91). These differences were irrespective of the HLA "shared epitope" (SE) status, and were observed similarly among SE+ as well as among SE- patients. After combining these data with other reported previously by us, from studies of CTLA4 49 (A/G) and -318 (C/T) polymorphisms, we conclude that the strongest association between CTLA4 gene polymorphisms and RA susceptibility occurs with the 3' UTR polymorphism.

[Docosahexaenoic acid (DHA) in fetal development and in infant nutrition]

Docosahexanoic acid (C22:6, DHA) is a highly unsaturated omega-3 fatty acid that forms part of the central nervous and visual system structures. DHA is synthesized from its precursor, alfa-linolenic acid, that is also a omega-3 fatty acid and can be obtained from vegetable oils. Marine organisms, specially fish, are good nutritional sources of DHA and eicosapentanoic acid (EPA), another omega-3 fatty acid that has a role in vascular homeostasis. DHA increases membrane fluidity, improving neurogenesis, synaptogenesis and the activity of retinal photoreceptors. The fetus, specially during the last trimester of pregnancy, has high DHA requirements. It is provided by the mother, since fetal DHA synthesis is negligible in this stage of development. Breast feeding provides DHA to the child, but most replacement artificial formulas do not provide this fatty acid. At the present moment, many products for infant nutrition contain DHA.

Differences in morphological age-related dental changes depending on postmortem interval

Morphological methods for age estimation from teeth have been developed and applied to samples without taking the postmortem interval into consideration. We studied differences in morphological age-related changes between fresh extracted teeth and teeth from human skeletal remains in order to develop appropriate dental age estimation methods according to the time after death. Forty-three permanent teeth from dental patients were compared to 37 teeth obtained from human skeletal remains with a postmortem interval from 21 to 37 years. Morphological age-related changes were investigated by measuring variables on intact and half-sectioned teeth. A new computer assisted image analysis procedure to avoid subjectivity was developed to measure variables in sectioned specimens. Dental color, translucency length, attrition, cementum apposition, and secondary dentin showed higher values in teeth from human skeletal remains than in fresh extracted teeth. Variables obtained by morphometric analysis of computer-generated images (tooth length, tooth width, root length, and root area) showed higher values in fresh extracted teeth than in teeth from skeletal remains. The postmortem interval affects age-related morphological changes, and therefore different methods should be used for teeth of unknown postmortem interval.