Phyllotaxis, pushed pattern-forming fronts, and optimal packing.

We demonstrate that the pattern forming partial differential equation derived from the auxin distribution model proposed by Meyerowitz, Traas, and others gives rise to all spiral phyllotaxis properties observed on plants. We show how the advancing pushed pattern front chooses spiral families enumerated by Fibonacci sequences with all attendant self-similar properties, a new amplitude invariant curve, and connect the results with the optimal packing based algorithms previously used to explain phyllotaxis. Our results allow us to make experimentally testable predictions.

Comparison of farmers in the agricultural health study to the 1992 and the 1997 censuses of agriculture.

Context: The Agricultural Health Study (AHS) is a large, prospective cohort study in the states of Iowa and North Carolina that has been developed to better understand how pesticides and other agricultural exposures relate to the occurrence of cancer and other diseases.

Purpose: This report compares the characteristics of AHS farmers to the Census of Agriculture to evaluate the generalizability of AHS findings.

Methods: We restricted the AHS to private pesticide applicators who enrolled in Iowa (n = 31,065) and in North Carolina (n = 17,239) between 1993 and 1997, and who identified themselves as living or working on a farm.

Clinical heterogeneity in mitochondrial DNA deletion disorders: a diagnostic challenge of Pearson syndrome.

The clinical presentation of mitochondrial DNA (mtDNA) disorders is quite diverse. Very often, the initial symptoms do not fit a specific disease, and diagnosis is difficult to make. We describe a patient who presented with macrocytic anemia.

Characteristics of pesticide use in a pesticide applicator cohort: the Agricultural Health Study.

Data on recent and historic pesticide use, pesticide application methods, and farm characteristics were collected from 35,879 restricted-use pesticide applicators in the first 2 years of the Agricultural Health Study, a prospective study of a large cohort of private and commercial licensed pesticide applicators that is being conducted in Iowa and North Carolina. (In Iowa, applicators are actually "certified," while in North Carolina they are "licensed"; for ease of reference the term license will be used for both states in this paper.) Commercial applicators (studied in Iowa only) apply pesticides more days per year than private applicators in either state.

Factors associated with self-reported, pesticide-related visits to health care providers in the agricultural health study.

To investigate factors associated with pesticide-related visits to health care providers (i.e., doctor or hospital visits), responses to self-administered questionnaires received from 35,879 licensed restricted-use pesticide applicators participating in the Agricultural Health Study were analyzed.

Molecular cloning of acid alpha-glucosidase cDNA of Japanese quail (Coturnix coturnix japonica) and the lack of its mRNA in acid maltase deficient quails.

Acid alpha-glucosidase (GAA) hydrolyzes alpha-1, 4 and alpha-1, 6 glucosidic linkages of oligosaccharides and degrades glycogen in the lysosomes. The full-length GAA I cDNA, pQAM8, was isolated from a cDNA library derived from Japanese quail liver. The cDNA is 3569 base pairs long and has an open reading frame capable of coding 932 amino acids.

Clinical and metabolic correction of pompe disease by enzyme therapy in acid maltase-deficient quail.

Pompe disease is a fatal genetic muscle disorder caused by a deficiency of acid alpha-glucosidase (GAA), a glycogen degrading lysosomal enzyme. GAA-deficient (AMD) Japanese quails exhibit progressive myopathy and cannot lift their wings, fly, or right themselves from the supine position (flip test). Six 4-wk-old acid maltase-deficient quails, with the clinical symptoms listed, were intravenously injected with 14 or 4.

Purification of recombinant human precursor acid alpha-glucosidase.

Large quantities of recombinant acid alpha-glucosidase are needed for in vivo experimentation of enzyme replacement therapy in Pompe disease. We describe a new purification method for the purification of this recombinant enzyme from tissue culture medium consisting of concanavalin A affinity chromatography, hydrophobic interaction chromatography, affinity chromatography on Superdex, and anion exchange chromatography. The new method is amenable to scale up, and has increased speed, and improved reproducibility with similar high yield and purification efficiency when compared to previous methods.

Evidence for the involvement of Glu-355 in the catalytic action of human beta-hexosaminidase B.

In a previous study the photoactivable affinity probe, 3-azi-1-[([6-3H]2-acetamido-2-deoxy-1-beta-D-galactopyranosyl)thio ]-b utane, was used to identify the active site of beta-hexosaminidase B, a beta-subunit dimer (Liessem, B., Glombitza, G. J.

Molecular basis of heat labile hexosaminidase B among Jews and Arabs.

Genotyping individuals for Tay-Sachs disease (TSD) is mainly based on the heat lability of beta-hexosaminidase (Hex) A (alphabeta) and the heat stability of Hex B (betabeta). Mutations in the HEXB gene encoding the beta-subunits of Hex that result in heat-labile Hex B thus may lead to erroneous enzymatic genotyping regarding TSD. Utilizing single strand conformation polymorphism (SSCP) analysis for all 14 exons of HEXB followed by direct sequencing of aberrant fragments, we screened individuals whose Hex B was heat labile.

Identification of domains in human beta-hexosaminidase that determine substrate specificity.

The lysosomal beta-hexosaminidases are dimers composed of alpha and beta subunits. beta-Hexosaminidase A (alphabeta) is a heterodimer, whereas hexosaminidase B (betabeta) and S (alphaalpha) are homodimers. Although containing a high degree of amino acid identity, each subunit expresses a unique active site that can be distinguished by a differential ability to hydrolyze charged substrates.

The Agricultural Health Study.

The Agricultural Health Study, a large prospective cohort study has been initiated in North Carolina and Iowa. The objectives of this study are to: 1) identify and quantify cancer risks among men, women, whites, and minorities associated with direct exposure to pesticides and other agricultural agents; 2) evaluate noncancer health risks including neurotoxicity reproductive effects, immunologic effects, nonmalignant respiratory disease, kidney disease, and growth and development among children; 3) evaluate disease risks among spouses and children of farmers that may arise from direct contact with pesticides and agricultural chemicals used in the home lawns and gardens, and from indirect contact, such as spray drift, laundering work clothes, or contaminated food or water; 4) assess current and past occupational and nonoccupational agricultural exposures using periodic interviews and environmental and biologic monitoring; 5) study the relationship between agricultural exposures, biomarkers of exposure, biologic effect, and genetic susceptibility factors relevant to carcinogenesis; and 6) identify and quantify cancer and other disease risks associated with lifestyle factors such as diet, cooking practices, physical activity, smoking and alcohol consumption, and hair dye use. In the first year of a 3-year enrollment period, 26,235 people have been enrolled in the study, including 19,776 registered pesticide applicators and 6,459 spouses of registered farmer applicators.

Transforming growth factor-beta (TGF-b) induced phosphorylation of the myristoylated alanine rich C kinase substrate (MARCKS) protein in ovarian granulosa cells is modulated by follicle stimulating hormone (FSH).

The mechanism by which TGF-b1 affects granulosa cell physiology as well as the modulation of TGF-b1 activity by FSH are not understood. We tested the hypothesis that TGF-b1 exerts its effects on granulosa cells via activation of protein kinase C (PKC). Immunoprecipitation of the MARCKS protein from 32P labeled rat granulosa cells was used to assay PKC activation.

Follicle-stimulating hormone increases c-fos mRNA levels in rat granulosa cells via a protein kinase C-dependent mechanism.

Recent evidence has been presented that follicle-stimulating hormone (FSH) stimulates the induction of granulosa cell c-fos protooncogene mRNA in vivo (Pennybacker and Herman (1989) J. Cell Biol. 109, 151A; Delidow et al.

Alterations in cell surface galactosyltransferase activity during limb chondrogenesis in brachypod mutant mouse embryos.

The autosomal mutation brachypod (bpH/bpH) in the mouse affects the development of precartilage mesenchymal condensation in the limb-bud. We have previously shown that this defect is localized to the expression of terminal N-acetylglucosamine (GlcNAc) glycoproteins in the plasma membrane (Elmer and Wright, '83). The present study is focused on cell surface galactosyltransferase (GalTase), an ectoenzyme that transfers galactose to its GlcNAc substrate.

Psychiatric disorders. A rural/urban comparison.

We studied rural/urban differences in the prevalence of nine psychiatric disorders from a community survey (part of the Epidemiologic Catchment Area Program) of 3,921 adults living in the Piedmont of North Carolina. Crude comparisons disclosed that major depressive episodes and drug abuse and/or dependence were more common in the urban area, whereas alcohol abuse/dependence was more common in the rural area. When prevalence for these disorders was stratified for age, sex, race, and education (factors that may confound urban/rural comparisons), a number of significant differences were identified, such as higher prevalence of major depression in female and white subjects and higher prevalence of alcohol abuse/dependence in the less educated subjects.

The meaning and measurement of age identity.

Lack of a broader theoretical framework and a relative neglect of measurement issues have hindered many previous studies of age identity. In this paper, a case is made for viewing age identity as a dimension of self-concept and two measurement techniques are empirically compared. The first is a single-item measure in which the individual chooses the age category which best suits him.