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PubMed2001

Modification of eating attitudes and behavior in adolescent girls: A controlled study.

OBJECTIVE: The aim of this study was to evaluate the effectiveness of a school-based eating disorder prevention program designed to reduce dietary restraint and concern about shape and weight among adolescent girls. METHOD: A total of 474 girls aged 13-14 years received the program as part of their normal school curriculum. An assessment-only control group included 386 pupils. Measures of eating disorder features, self-esteem, and knowledge were administered before and after the intervention and at 6-month follow-up. RESULTS: Immediately following the intervention, there was a small reduction in dietary restraint and attitudes to shape and weight in the index group, whereas there was no change in the control group. This reduction was not maintained at 6-month follow-up although the dietary restraint scores of the index group remained lower than those of the control group. DISCUSSION: This prevention program achieved change in eating attitudes and behavior, although the change was modest in size and not sustained. Focusing on a high-risk subgroup of dieters might be a more fruitful primary prevention strategy.

Adolescent↗
PubMed2003

Childhood vaccine development: an overview.

Vaccines against childhood diseases represent some of the most important applications of 20th-century pediatric research. This survey examines how the components of the current U.S. immunization schedule emerged in three phases during the course of the century. The first phase, after the development of bacterial culture techniques, witnessed numerous efforts in the early 1900s to develop bacterial vaccines. It proved most fruitful with respect to diphtheria, tetanus, and pertussis. The rise of viral tissue culture techniques in the 1950s brought about a second phase of innovation resulting in vaccines against polio, measles, mumps, rubella, and varicella. A third wave of innovation, still very much alive, has drawn on a variety of new technologies and led to vaccines against hepatitis B, Haemophilus influenzae type b, pneumococcus, and still other organisms. Although basic science research has thus been a primary factor shaping the history of vaccine development, the collaboration between the academic, private, and public sectors critical to its application has not always proceeded smoothly. The history of vaccine research and development has important implications for today, as a variety of factors threaten to fragment this network.

Bacterial Vaccines↗
PubMed2002

Shaping the vertebrate body plan by polarized embryonic cell movements.

Polarized cell movements shape the major features of the vertebrate body plan during development. The head-to-tail body axis of vertebrates is elongated in embryonic stages by "convergent extension" tissue movements. During these movements cells intercalate between one another transverse to the elongating body axis to form a narrower, longer array. Recent discoveries show that these polarized cell movements are controlled by homologs of genes that control the polarity of epithelial cells in the developing wing and eye of the fruit fly, Drosophila.

Animals↗
PubMed1995

Diurnal patterns of cocaine and heroin self-administration in rhesus monkeys responding under a schedule of multiple daily sessions.

A number of non-pharmacological factors have been shown to influence drug self-administration in experimental animals. This report examines diurnal changes in drug self-administration by rhesus monkeys trained to self-administer food (1gm fruit-flavored pellets) and cocaine (0.01 or 0.032mg/kg/injection) under a second order FR4 (VR16:S) schedule during four daily food and drug self-administration sessions. Saline, different unit doses of cocaine (0.001-0.1mg/kg/injection) or different unit doses of heroin (0.0001-0.01mg/kg/injection) were substituted for the maintenance dose of cocaine during drug sessions. Dose-effect curves relating unit dose of cocaine or heroin to the number of injections per session displayed an inverted U-shape during each of the four daily drug sessions. When 0.032mg/kg/injection cocaine or 0.0032mg/kg/injection heroin were available, monkeys usually self-administered the maximum number of injections during all four drug sessions. Substitution of saline or lower unit doses of cocaine (0.001-0.01mg/kg/injection) or heroin (0.0001-0.001mg/kg/injection) decreased the number of injections/session; however, these decreases were consistently greater during the evening (20.00-21.00h) and morning (07.00-08.00h) sessions than during the afternoon sessions (12.00-13.00h and 16.00-17.00h). As a result, the ascending limbs of the cocaine and heroin dose-effect curves for the evening and morning sessions were shifted to the right of the ascending limbs of the dose-effect curves for the afternoon sessions. Moreover, when saline was substituted for cocaine for only two sessions per day, drug self-administration decreased more during the evening and morning sessions even when the cocaine was available during those sessions. These findings suggest a diurnal variation in cocaine and heroin self-administration. Specifically, drug self-administration during the evening and morning sessions appears to be more sensitive to a decrease in reinforcer magnitude than responding during the afternoon sessions. These findings confirm and extend previous reports of the influence of non-pharmacological factors on drug self-administration.

Journal Article↗
PubMed1997

Inhibitory effects of persimmon (Diospyros kaki) extract and related polyphenol compounds on growth of human lymphoid leukemia cells.

We have investigated the effects of persimmon (Diospyros kaki) extract (PS) and related polyphenol compounds such as catechin (C), epicatechin (EC), epicatechingallate (ECG), epigallocatechin (EGC), and epigallocatechingallate (EGCG) on the growth of human lymphoid leukemia Molt 4B cells. We found that PS, ECG, EGC, and EGCG strongly inhibited the growth of the cells in a dose-dependent manner, while C and EC inhibited the growth of the cells only moderately. Ornithine decarboxylase (ODC), a rate-limiting enzyme of polyamine biosynthesis, was inhibited by 10-20% by these polyphenol compounds. The morphology of the Molt 4B cells indicated severe damage 3 days after treatment with PS, ECG, EGC, and EGCG. Irregular shape of the cells and DNA fragmentation were observed in PS, ECG, EGC, or EGCG-treated cells. These results suggest that PS, ECG, EGC, and EGCG induce apoptosis (programmed cell death) of Molt 4B cells.

Antineoplastic Agents↗
PubMedDate not supplied

Nursing-bottle syndrome caused by prolonged drinking from vessels with bill-shaped extensions.

Our investigating 186 infants between the ages of one and six with carious destruction of the maxillary primary incisors, it was learned which risk factors were responsible for the condition known as nursing bottle syndrome. One hundred and twenty-eight infants (68.8 percent) were given a nursing bottle, twelve (6.5 percent) a feeding cup or other bottles with bill- shaped extensions, and forty-one (22.0 percent) both a nursing bottle and vessels with bill-shaped extensions; in all cases the feeding was excessive and prolonged beyond the first year of life. An additional five infants (2.7 percent) were breast-fed excessively beyond the first year. The results confirm the risk of tooth destruction, typical of nursing bottle syndrome, by prolonged and frequent consumption of cariogenic beverages from vessels with bill-shaped extensions. It is important, therefore, that a warning regarding dental health hazards of such feeding methods be issued.

Age Factors↗
PubMed2003

Modelling of Dictyostelium discoideum slug migration.

The development of most multicellular organisms involves differential movement of cells resulting in the formation of tissues. The principles governing these movements are poorly understood. One exception is the formation of the slug in the social amoebae Dictyostelium discoideum. The slug forms by the chemotactic aggregation of up to 10(5) starving cells, it is motile and migrates in response to light and temperature gradients to the surface of the soil to form a fruiting body consisting of a stalk supporting a spore head. Slug migration and behaviour result from coordinated chemotactic movement of the individual cells in the slug. Waves of a chemoattractant, most likely cAMP, are periodically initiated in the tip of the slug and propagate towards the back of the slug resulting in periodic forward movement of individual cells as well as the whole slug. Here we develop a model to investigate how wave propagation and cell movement interacts to result in migration and shape changes of the slug. The slug tissue is modelled as an incompressible liquid, in which waves of chemoattractant are generated in an excitable manner. The liquid is "active", i.e. it is able to generate body forces in response to the gradients of the chemoattractant. These forces lead to the formation of flows (representing chemotactically moving cells) and result in slug movement and shape changes. The model provides a theoretical framework for the understanding of the interactions between cell-cell signalling and cell movement, which govern slug behaviour and tissue morphogenesis.

Animals↗
PubMed1999

Developmental and cell biological functions of the Drosophila DEAD-box protein abstrakt.

BACKGROUND: DEAD-box proteins are a large family of proteins found in bacteria, plants and animals, but only few have been analysed functionally. They are involved in the regulation of various aspects of RNA processing and metabolism, including splicing, transport and translation. The study of their function in multicellular organisms has been restricted to a few special cases, such as the Vasa protein in the fruit fly Drosophila. RESULTS: We show that abstrakt, a gene originally identified genetically by its effect on axon outgrowth and fasciculation of the Bolwig nerve, encodes a new Drosophila DEAD-box protein of which the closest homologue is a human gene of unknown function. Using temperature-sensitive alleles to assay its function, we found that abstrakt is essential for survival at all stages throughout the life cycle of the fly. Mutants show specific defects in many developmental processes, including cell-shape changes, localisation of RNA and apoptosis. CONCLUSIONS: Abstrakt is not globally required for RNA splicing, transport, subcellular localisation or translation. Nevertheless, there is a widespread requirement for Abstrakt during post-transcriptional gene expression. Abstrakt must affect processing of specific subsets of RNAs, suggesting that differential post-translational control during development is more common than previously suspected.

Amino Acid Sequence↗
PubMed2000

Morphological variation and female reproductive success in two sympatric Trillium species: evidence for phenotypic selection in Trillium erectum and Trillium grandiflorum (Liliaceae).

I investigated the mating systems and phenotypic variation of two sympatric spring ephemerals, Trillium erectum and T. grandiflorum (Liliaceae), and phenotypic selection acting through female reproductive success for 11 morphological characters in five sympatric populations of the two species. I examined the degree of self-compatibility, pollinator-visitation rates, and pollen limitation of fruit and seed production in both species. Both Trillium species were self-compatible, but outcrossed flowers produced more successful fruits and seeds than self-pollinated flowers. Pollinator-visitation rates to the two species were low compared to other insect-pollinated spring ephemerals. In addition, both T. erectum and T. grandiflorum experienced pollen limitation in fruit and/or seed production; however, levels of fecundity in both species may be influenced by resource availability as well. I found significant phenotypic variation in 11 morphological characters within and among the five study populations. The sizes of all morphological characters were positively correlated. In general, larger T. erectum and T. grandiflorum produced more seeds. Phenotypic selection analysis revealed that direct and indirect selection acted on the size of morphological characters for both species. But there was no detectable selection acting on plant shape. This study reveals that variation in plant size exists within and among populations of both species, and this variation is associated with variance in female reproductive success. Spatial and temporal variation in pollinator and/or resource abundance may play a role in the phenotypic variation exhibited by both Trillium species.

Journal Article↗
PubMed2005

Carotenoid availability affects the development of a colour-based mate preference and the sensory bias to which it is genetically linked.

Regardless of their origins, mate preferences should, in theory, be shaped by their benefits in a mating context. Here we show that the female preference for carotenoid colouration in guppies (Poecilia reticulata) exhibits a phenotypically plastic response to carotenoid availability, confirming a key prediction of sexual selection theory. Earlier work indicated that this mate preference is genetically linked to, and may be derived from, a sensory bias that occurs in both sexes: attraction to orange objects. The original function of this sensory bias is unknown, but it may help guppies find orange-coloured fruits in the rainforest streams of Trinidad. We show that the sensory bias also exhibits a phenotypically plastic response to carotenoid availability, but only in females. The sex-specificity of this reaction norm argues against the hypothesis that it evolved in a foraging context. We infer instead that the sensory bias has been modified as a correlated effect of selection on the mate preference. These results provide a new type of support for the hypothesis that mate preferences for sexual characters evolve in response to the benefits of mate choice--the alternatives being that such preferences evolve entirely in a non-mating context or in response to the costs of mating.

Analysis of Variance↗
PubMed1997

["Associative" visual agnosia for objects, pictures, faces and letters with altitudinal hemianopia].

We report a 63-year-old right-handed man with the associative visual agnosia and bilateral altitudinal hemianopia. Neurological examination revealed fair visual acuity and normal ocular movement. Other cranial-nerve, motor, sensory, and autonomic functions were normal. The brain MRI showed multiple infarction involving the right fusiform and lingual gyri extending to the adjacent white matter of the occipito-temporal lobes and posterior part of the parahippocampus, the left fusiform and lingual gyri, and multiple lacunae in bilateral basal ganglia. Cerebral angiography demonstrated occlusion at the P1 portions of bilateral posterior cerebral arteries. 123I IMP-SPECT revealed decreased perfusion in bilateral occipital lobes, worse on the right. Visual evoked fields showed normal pattern of P100 m on bilateral occipital lobes. Neuropsychologically he was alert and oriented in place. In WAIS-R, he could not perform any of performance subtests, while his VIQ was 72. His verbal and visual memory was impaired. His visual perception of forms seemed to be almost preserved. He could copy simple drawing precisely, although he could not recognize the drawing just copied. He could match pictures, letters and photographs of faces. His visual identification of forms, on the other hand, was severely disturbed. He could identify only simple geometrical figures, but not simple drawings such as an apple or the face of his daughter. Reading Kanji was impaired and he read Kana in letter-by-letter manner. Tactile identification of objects was much better than visual one. Naming objects from verbal description was well preserved. Drawing fruits or cars from memory was intact. These data suggests that the present case had fairly good visual perception as was demonstrated by good copying and matching performance, and the case could be classified into the associative type of visual agnosia if the dichotomized classification of apperceptive and associative type is employed. However, closer look at his way of copying clearly showed that he copied in piecemeal fashion, suggesting difficulty in seeing a figure as a dynamic whole. It is possible that fine and precise discrimination of shape and pattern is subserved by the bilateral ventral or occipito-temporal visual system which was compromized in the present case.

Agnosia↗
PubMed2002

Separating the apples and oranges in the fruit cocktail: the mixed results of psychosocial interventions on cancer survival.

In past reviews of the literature on psychosocial interventions for cancer patients, different reviewers have reached disparate conclusions about the ability of a psychosocial intervention to have an impact on cancer survival. This article highlights some of the basis for differences of opinion, including the range of psychosocial interventions provided to patients and the challenges inherent in conducting research studies of this type. Social workers who work with cancer patients at vulnerable times need to understand what the current evidence shows can be gained from participation in a psychosocial intervention. Several key questions have been identified that can provide the basis for future rigorous studies. The role of the social worker in participating and shaping research on the relationship of psychosocial intervention and cancer survival is also discussed.

Humans↗
PubMed1985

Ultrastructural observations on the cytoarchitecture of axons processed by rapid-freezing and freeze-substitution.

The structure and organization of axons in the cervical connective of wild-type Drosophila fruit flies were examined in anticipation of studies of various neurological mutants. Dissected flies were rapid-frozen from the living state against a copper block cooled with liquid helium, freeze-substituted, and prepared for electron microscopic examination of thin sections. These cryotechniques showed new details of the structure of cell organelles and cytoplasm in Drosophila axons. The cytoplasmic matrix of axons and glia consists of a material with a fine granular texture enmeshed in a three-dimensional meshwork of short, fine filaments which vary in shape, size and electron density. No neurofilaments are present, but bundles of microtubules are interwoven into the filamentous matrix of the axoplasm. The round wall of microtubules (27 nm overall diameter) is composed of twelve cylindrical protofilaments with a typical substructural periodicity. Mitochondria frequently make contact with microtubules in both axons and glial processes. A thin layer of electron-dense filamentous matrix, which appears to be an axonal basal lamina, contacts most of the axonal exoplasmic surface, especially that of axons where they are surrounded by processes of glial cells, but is scant wherever single axons are contiguous. Thus, an axonal basal lamina occupies the constricted spaces around axons, where extracellular K+ accumulates during neural activity.

Animals↗
PubMed2006

Ubc9 regulates mitosis and cell survival during zebrafish development.

Many proteins are modified by conjugation with Sumo, a gene-encoded, ubiquitin-related peptide, which is transferred to its target proteins via an enzymatic cascade. A central component of this cascade is the E2-conjugating enzyme Ubc9, which is highly conserved across species. Loss-of-function studies in yeast, nematode, fruit fly, and mouse blastocystes point to multiple roles of Ubc9 during cell cycle regulation, maintenance of nuclear architecture, chromosome segregation, and viability. Here we show that in zebrafish embryos, reduction of Ubc9 activity by expression of a dominant negative version causes widespread apoptosis, similar to the effect described in Ubc9-deficient mice. However, antisense-based knock down of zygotic ubc9 leads to much more specific defects in late proliferating tissues, such as cranial cartilage and eyes. Affected cartilaginous elements are of relatively normal size and shape, but consist of fewer and larger cells. Stainings with mitotic markers and 5-Bromo-2'-deoxyuridine incorporation studies indicate that fewer chondrocyte precursors are in mitosis, whereas the proportion of cells in S-phase is unaltered. Consistently, FACS analyses reveal an increase in the number of cells with a DNA content of 4n or even 8n. Our data indicate an in vivo requirement of Ubc9 for G2/M transition and/or progression through mitosis during vertebrate organogenesis. Failed mitosis in the absence of Ubc9 is not necessarily coupled with cell death. Rather, cells can continue to replicate their DNA, grow to a larger size, and finish their normal developmental program.

Animals↗
PubMed2004

Identification of biomechanical factors involved in stem shape variability between apricot tree varieties.

BACKGROUND AND AIMS: Stem shape in angiosperms depends on several growth traits such as elongation direction, amount and position of axillary loads, stem dimensions, wood elasticity, radial growth dynamics and active re-orientation due to tension wood. This paper analyses the relationship between these biomechanical factors and stem shape variability. METHODS: Three apricot tree varieties with contrasting stem shape were studied. Growth and bending dynamics, mechanical properties and amount of tension wood were measured on 40 1-year-old stems of each variety during one growth season. Formulae derived from simple biomechanical models are proposed to quantify the relationship between biomechanical factors and re-orientation of the stems. The effect of biomechanical factors is quantified combining their mechanical sensitivity and their actual variability. RESULTS: Re-orientations happened in three main periods, involving distinct biomechanical phenomena: (a) passive bending due to the increase of shoot and fruit load at the start of the season; (b) passive uprighting at the fall of fruits; (c) active uprighting due tension wood production at the end of the season. Differences between varieties mainly happened during periods (a) and (b). CONCLUSIONS: The main factors causing differences between varieties are the length/diameter and the load/cross-sectional area ratios during period (a). Wood elasticity does not play an important role because of its low inter-variety variability. Differences during period (b) are related to the dynamics of radial growth: varieties with early radial growth bend weakly upward because the new wood layers tend to set them in a bent position. The action of tension wood during period (c) is low when compared with passive phenomena involved in periods (a) and (b).

Biomechanical Phenomena↗
PubMed2005

Survivors of childhood cancer and their guardians.

BACKGROUND: Survivors of childhood cancer are at increased risk for osteoporosis, cardiovascular disease, and second malignancies-conditions for which modifiable risk factors are recognized and lifestyle interventions have shown benefit. Although some data regarding health behaviors of this population exist, receptivity to health promotion is largely unknown. METHODS: A survey was mailed to 380 survivors (age range, 11-33 years) of childhood leukemia, lymphoma, or central nervous system carcinomas (and guardians of survivors < 18 years old) to elicit data on exercise, dietary intake of calcium, fat, and fruits and vegetables, smoking status, readiness to pursue lifestyle change, quality of life, and interest in various health interventions. RESULTS: Responses from 209 survivors (a 55% response rate) suggested that most did not meet guidelines for fruit and vegetable consumption (79%), calcium intake (68%), or exercise (52%), 42% were overweight/obese, and 84% consumed > 30% of calories from fat. Older (> 18 years) compared with younger (< 18 years) survivors were more likely to smoke (17% vs. 1%), to be obese (21.6% vs. 14.6%), and to have suboptimal calcium intakes (75.6% vs. 57.6%). No differences in lifestyle behaviors were observed between cancer groups. Compared with interventions aimed at weight control, improving self-esteem, or smoking cessation, the highest levels of interest were found consistently for interventions aimed at getting in shape and eating healthy. Survivors preferred mailed interventions to those delivered in-person, by telephone counselors, or via computers. CONCLUSIONS: Survivors of childhood cancer practiced several suboptimal health behaviors. Health promotion interventions aimed at areas of interest and delivered through acceptable channels have the potential to improve long-term health and function of this vulnerable population.

Adolescent↗
PubMed2005

Biodemography of a long-lived tephritid: reproduction and longevity in a large cohort of female Mexican fruit flies, Anastrepha ludens.

Age of sexual maturity, daily and lifetime reproductive rates, and life span were recorded in a laboratory cohort of Mexican fruit flies consisting of over 1100 females maintained individually. The results revealed that, relative to the medfly, the Mexfly is slower maturing (14 vs 17 days), more fecund (1400 vs 650-1100 eggs/female), and longer lived (50 vs 35 days). The results reinforced the generality of several earlier findings on the medfly including the deceleration of mortality at older ages and the weakness of the correlation between the rate of egg laying at early ages and both subsequent reproduction and remaining longevity. Discussion includes perspectives on the role of artificial selection in shaping the demographic traits of the mass-reared strain of Mexfly used in this study, as well as the overall significance of large scale biodemographic studies in understanding aging and longevity.

Aging↗
PubMed2004

Brefeldin A production by Phoma medicaginis in dead pre-colonized plant tissue: a strategy for habitat conquest?

Phoma medicaginis was isolated as the dominant endophyte from surface-sterilized shoots of Medicago sativa and M. lupulina growing outdoors. Plants were either symptomless or showed signs of infection in the shape of limited lesions which sometimes contained melanized pycnidial initials. Rapid colonization of host tissue and sporulation were observed within 9 d on dead plant material upon incubation in a moist chamber. Such colonized material, but not freshly harvested living tissue, contained brefeldin A (1.7 microg g(-1) D.W.). This toxin was also produced in pure culture (20 mg l(-1)) and in artificially inoculated autoclaved M. sativa stems (3 mg g(-1) D.W. =920 microg ml(-1)). The latter concentration of brefeldin A should be similar to that produced within a fruiting lesion of P. medicaginis and suppressed spore germination and growth of nine of 11 common phylloplane fungi tested. This metabolite may thus have a function in substrate defence after the switch from the endophytic to the saprotrophic period in the life-cycle of P. medicaginis following the death of infected host tissue.

Ascomycota↗