National Institutes of Health support for research and training: future of pediatrician scientists

Agrobacterium tumefaciens transfers part of its Ti plasmid, the T-DNA, to plant cells during tumorigenesis. It is routinely used for the genetic modification of a wide range of plant species. We report that A. tumefaciens can also transfer its T-DNA efficiently to the filamentous fungus Aspergillus awamori, demonstrating DNA transfer between a prokaryote and a filamentous fungus. We transformed both protoplasts and conidia with frequencies that were improved up to 600-fold as compared with conventional techniques for transformation of A. awamori protoplasts. The majority of the A. awamori transformants contained a single T-DNA copy randomly integrated at a chromosomal locus. The T-DNA integrated into the A. awamori genome in a manner similar to that described for plants. We also transformed a variety of other filamentous fungi, including Aspergillus niger, Fusarium venenatum, Trichoderma reesei, Colletotrichum gloeosporioides, Neurospora crassa, and the mushroom Agaricus bisporus, demonstrating that transformation using A. tumefaciens is generally applicable to filamentous fungi.     

Illness attributions and hopelessness depression: The role of hopelessness expectancy.

According to hopelessness theory, hopelessness expectancy is the proximal, sufficient cause of hopelessness depression. Consequently, hopelessness expectancy is viewed as mediating the influence of all other factors on hopelessness depression. Using a longitudinal research design, hopelessness expectancy was examined as a mediator of the relation between illness attributions and hopelessness depression in a sample of 57 adults with rheumatoid arthritis. Although hopelessness expectancy was a strong predictor of hopelessness depression, it moderated rather than mediated the relation between attributions and depression. Finding support for a moderating rather than a mediating model is inconsistent with theory but is consistent with the findings of J. H. Riskind et al (1987). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In vitro toothbrush-dentifrice abrasion of resin-modified glass ionomers

OBJECTIVES: The three purposes of this study are to: (1) describe the relationship between the prevalence of coronal caries and root caries; (2) describe the relationship between the three-year incidence of coronal caries and root caries; and (3) if the two conditions are associated, develop a multiple regression model that identifies characteristics distinguishing people who had increments of both root caries and coronal caries from people who had increments of either coronal caries or root caries, or who had no new caries. METHODS: Dental examinations and interviews were conducted in the homes of a randomly selected, stratified sample of people over the age of 65 years in five North Carolina counties. The relationships between coronal and root D and DF were analyzed through contingency table analyses, and ordinal logistic regression was used to identify characteristics that differentiated people who had both coronal and root D over the three years from people who had either coronal or root D and people who had no new disease. RESULTS: Evidence of root and coronal caries in whites was much more likely to be in the form of fillings, while for blacks, it was more likely to be in the form of untreated decay. Prevalence rates of coronal and root D and DF were significantly associated for both blacks and whites. Incidence rates based on DF indicated that root and coronal caries were not associated in whites, but were associated in blacks. People more likely to experience both types of caries had more gingival recession at baseline, greater average attachment loss over the three years, and lactobacilli at baseline. In addition, the presence of Porphymonas gingivalis at three years was important for whites. CONCLUSIONS: It appears that coronal and root caries do tend to appear together in the same individuals, but fillings attenuate that relationship. The impact of dental treatment on the epidemiology of dental caries appears to be considerable and calls into question whether the F component of the caries index is related to disease as defined by epidemiologic criteria.     

Determination of chromium valence over the range Cr(0)–Cr(VI) by electron energy loss spectroscopy

Chromium is a redox active 3d transition metal with a wide range of valences (−2 to +6) that control the geochemistry and toxicity of the element. Therefore, techniques that measure Cr valence are important bio/geochemical tools. Until now, all established methods to determine Cr valence were bulk techniques with many specific to a single, or at best, only a few oxidation state(s). We report an electron energy loss spectroscopy (EELS) technique along with an extensive suite of affined reference spectra that together, unlike other methods, can determine Cr valence (or at least constrain the possible valences) at high-spatial resolution (tens-of-nanometer scale) across a wide valence range, Cr(0)–Cr(VI). Fine structure of Cr-L_2,3 edges was parametrized by measurement of the chemical shift of the L₃ edge and the ratio of integrated intensity under the L₃ and L₂ edges. These two parameterizations were correlated to Cr valence and also the dⁿ orbital configuration which has a large influence on L-edge fine structure. We demonstrate that it is not possible to unambiguously determine Cr valence from only one fine-structure parameterization which is the method employed to determine metal valence by nearly all previous EELS studies. Rather, multiple fine-structure parameterizations must be used together if the full range of possible Cr valences is considered. However even with two parameterizations, there are limitations. For example, distinguishing Cr(IV) from Cr(III) is problematic and it may be difficult to distinguish low-spin Cr(II) from Cr(III). Nevertheless, when Cr is known to be divalent, low- and high-spin dⁿ orbital configurations can be readily distinguished.     

Ahch, the mouse homologue of DAX1: cloning, characterization and synteny with GyK, the glycerol kinase locus

We cloned the murine full-length cDNA encoding Ahch, the mouse homologue of DAX1 (DSS-AHC Region on Human X Chromosome, Gene1) which is the gene responsible for human X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism (HH). Sequence analysis revealed that the murine and human cDNAs have 65% aa identity and 75% aa similarity overall. The cysteine residues in the putative DNA binding domain, which may interact with Zn2+ ions to form zinc fingers, are 100% conserved between the two species, indicating that the novel zinc-finger structures in DAX1 may be functional. In addition, mouse interspecific backcrosses show that the Ahch gene is closely linked to the glycerol kinase locus, GyK, on the mouse X chromosome, indicating that the order of the loci is conserved in this syntenic region between mouse and human.     

Rehabilitation planned in accordance with the Luria neuropsychological investigation: A case history of a patient with left sided aneurysm.

After suffering a rupture of a left-sided aneurysm on the middle cerebral artery with prolonged arterial spasms, the prognosis for recovery of speech and motor functions of a 27-yr-old male patient was considered to be poor. Based on a Luria neuropsychological investigation that revealed many areas of preserved brain functions, rehabilitation efforts were directed toward training of specific abilities as well as compensatory skills using intact functions. This case demonstrates the interaction between the training program and the levels of motivation and persistence of the S and his family necessary to produce optimal rehabilitation outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hemi- and Homozygous Loss-of-Function Mutations in DSG2 (Desmoglein-2) Cause Recessive Arrhythmogenic Cardiomyopathy with an Early Onset

About 50% of patients with arrhythmogenic cardiomyopathy (ACM) carry a pathogenic or likely pathogenic mutation in the desmosomal genes. However, there is a significant number of patients without positive familial anamnesis. Therefore, the molecular reasons for ACM in these patients are frequently unknown and a genetic contribution might be underestimated. Here, we used a next-generation sequencing (NGS) approach and in addition single nucleotide polymor-phism (SNP) arrays for the genetic analysis of two independent index patients without familial medical history. Of note, this genetic strategy revealed a homozygous splice site mutation (DSG2–c.378+1G>T) in the first patient and a nonsense mutation (DSG2–p.L772X) in combination with a large deletion in DSG2 in the second one. In conclusion, a recessive inheritance pattern is likely for both cases, which might contribute to the hidden medical history in both families. This is the first report about these novel loss-of-function mutations in DSG2 that have not been previously identi-fied. Therefore, we suggest performing deep genetic analyses using NGS in combination with SNP arrays also for ACM index patients without obvious familial medical history. In the future, this finding might has relevance for the genetic counseling of similar cases.     

Patterns in the crustacean zooplankton community in Lake Winnipeg,Manitoba: Response to long-term environmental change

Changes in the crustacean zooplankton community composition and abundance in Lake Winnipeg (1969–2006) provide a rare opportunity to examine their response to environmental changes in the largest naturally eutrophic lake on the Canadian prairies. Since 1929, zooplankton species composition in Lake Winnipeg has changed little except for the addition of the invasive cladoceran, Eubosmina coregoni in 1994. The dominant taxa in the lake in summer include: Leptodiaptomus ashlandi, Acanthocyclops vernalis, Diacyclops thomasi, Daphnia retrocurva, Daphnia mendotae, Diaphanosoma birgei, Eubosmina coregoni, and Bosmina longirostris. Climate-accelerated nutrient loading to southern Lake Winnipeg over the last two decades has led to increased phytoplankton abundance and higher frequency of cyanobacterial blooms especially in its northern basin. Crustacean zooplankton have likewise increased especially in the North Basin, but less so in the more nutrient rich South Basin, possibly as a consequence of higher densities of pelagic planktivorous fish and light-limited primary production compared with the more transparent North basin (Brunskill et al., 1979, 1980). Calanoid copepods play a larger role in the South basin food web in contrast to cyclopoid copepods and Cladocera in the North basin. The study begins to fill the recognized gap in understanding of Lake Winnipeg's food web structure and provides a baseline for evaluating ongoing changes in the zooplankton community with the arrival of new non-indigenous taxa, e.g. Bythotrephes longimanus and Dreissena polymorpha. It reinforces previous work demonstrating that zooplankton provide valuable indices toward evaluating the health of an ecosystem.