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PubMed2001

Growth tracks in early childhood.

AIM: Child growth is modulated by numerous factors and, particularly in infancy and early childhood, often tends to follow apparently irregular patterns, with many centiles crossed before the later growth channels are reached. The aim of this study was to visualize the diversity of individual growth. DESIGN: The study investigated 333 girls and 329 boys without chronic illnesses from four paediatric practices in Kiel, Germany. The children were measured on natural, i.e., on various occasions, when they were presented to their doctors for preventive care examinations and for minor illnesses, at the age of 0.25 (range +/- 0.08) y, 0.5 (range +/- 0.16) y, 0.75 (range +/- 0.16) y, 1.0 (range +/- 0.25) y, and at the ages of 1.5, 2, 3, 4 and 5 (range +/- 0.25) y. Each individual growth curve was converted into a series of height SDS (standard deviation scores) using one of the most reputable longitudinal German growth studies as background reference. Height SDS was then converted into residual height SDS (differences between height SDS of each measurement and average personal height SDS of the respective child). Cluster analysis was used to identify groups of children (clusters) with similarities in residual height SDS patterns (growth tracks). The clusters contained a minimum of at least 10 children. Single children or small sets of individuals below the minimum number were rejected from further analysis. RESULTS: In males, 10 growth tracks were identified, each consisting of 11 to 52 boys. Growth in 111 boys was so heterogeneous that they could not be assigned to growth tracks. In females, 11 growth tracks were identified, each consisting of 12 to 48 girls; 112 girls could not be assigned. Approximately 7% of boys and 15% of girls showed evidence of a mild intermittent growth spurt at the end of infancy. Some growth tracks were almost horizontal, or showed declining residual height SDS up to the age of 3 and 4 y, with no evidence of growth spurts during early childhood. Others showed sharply declining growth in early infancy, or irregular patterns. Similar results were obtained when using cross-sectional standards as background reference. CONCLUSION: Cluster analysis provides evidence that the substantial diversity in infant and early child growth, is limited to a small number of narrow but characteristic tracks of yet unknown biological significance.

Algorithms↗

PubMed1998

Developmental changes and variability in the early lexicon: a study of French children's naturalistic productions.

This paper investigates developmental changes, as well as inter-linguistic and inter-individual variations, in the expansion and composition of French children's early lexicons. Two studies were conducted using children's naturalistic productions: a longitudinal study of one child between 1;2 and 2;6, and a cross-sectional study of two groups (12 children each) aged 1;8 and 2;6. Analyses indicate that lexical productivity (measured in types, tokens, and new words) strongly increased with age, whereas lexical diversity showed almost no developmental progression. Nouns and para-lexical elements (including interjections, fillers or formulas) were predominant until 1;8 and decreased over time, while predicates and grammatical words increased. As compared to English, French development was characterized by less frequent nouns, initially more frequent predicates, and a remarkable expansion of grammatical words. Inter-individual variability in lexical productivity, in lexical diversity, and in the proportions of different categories was more marked at 1;8 than at 2;6. Lexical profiles found at 1;8 suggest the existence of more diversified organizational patterns than those captured in the referential-expressive distinction.

Age Factors↗

PubMed1985

Ultrastructural aspects of cryofixed nerves.

The ultrastructure of the optic and trigeminal nerves of the rat, cryofixed by use of a liquid nitrogen-propane jet, was examined, paying special attention to the myelin sheath and the cytoskeleton of the axoplasm. The cytoskeleton of the axoplasm is formed by a meshwork of neurofilaments and microtubules connected both to each other and also to the cell organelles and axolemma. These cross-linkers are fixed to the longitudinal neurofilaments in a helical arrangement, which could be a morphological substrate for the diverse axonal transport phenomena. The myelin sheath is formed by concentrically apposed membrane pairs, which are not fused together. The corresponding major and intraperiod lines seen using classical electron microscopy are in fact fissures that are obscured by the pattern of the selective deposition of osmium at certain sites and cannot be interpreted as specific structures. The cryofixed myelin membranes have the appearance of predominantly globular subunits arranged in an asymmetrical bilayer. The globular particles are of diverse diameter and occupy varying positions within the membrane. The tight junctions or zonulae occludentes of the myelin are formed by arrays of isolated particles, and consequently the fibril formation seems to be a result of the chemical fixation.

Animals↗

PubMed2001

Spatial population genetic structure in Trillium grandiflorum: the roles of dispersal, mating, history, and selection.

The roles of the various potential ecological and evolutionary causes of spatial population genetic structure (SPGS) cannot in general be inferred from the extant structure alone. However, a stage-specific analysis can provide clues as to the causes of SPGS. We conducted a stage-specific SPGS analysis of a mapped population of about 2000 Trillium grandiflorum (Liliaceae), a long-lived perennial herb. We compared SPGS for juvenile (J), nonreproductive (NR), and reproductive (R) stages. Fisher's exact test showed that genotypes had Hardy-Weinberg frequencies at all loci and stage classes. Allele frequencies did not differ between stages. Bootstrapped 99% confidence intervals (99%CI) indicate that F-statistic values are indistinguishable from zero, (except for a slightly negative FIT for the R stage). Spatial autocorrelation was used to calculate f the average kinship coefficient between individuals within distance intervals. Null hypothesis 99%CIs for f were constructed by repeatedly randomizing genotypic locations. Significant positive fine-scale genetic structure was detected in the R and NR stages, but not in the J stage. This structure was most pronounced in the R stage, and declined by about half in each remaining stage: near-neighbor f = 0.122, 0.065, 0.027, for R, NR, and J, respectively. For R and NR, the near-neighbor f lies outside the null hypothesis 99%CI, indicating kinship at approximately the level of half-sibs and first cousins, respectively. We also simulated the expected SPGS of juveniles post dispersal, based on measured R-stage SPGS, the mating system, and measured pollen and seed dispersal properties. This provides a null hypothesis expectation (as a 99%CI) for the J-stage correlogram, against which to test the likelihood that post-dispersal events have influenced J-stage SPGS. The actual J correlogram lies within the null hypothesis 99%CI for the shortest distance interval and nearly all other distance intervals indicating that the observed low recruitment, random mating and seed dispersal patterns are sufficient to account for the disappearance of SPSG between the R and the J stages. The observed increase in SPGS between J and R stages has two potential explanations: history and local selection. The observed low total allelic diversity is consistent with a past bottleneck: a possible historical explanation. Only a longitudinal stage-specific study of SPGS structure can distinguish between historical events and local selection as causes of increased structure with increasing life history stage.

Genetics, Population↗

PubMed2006

Sequence variation in the T-cell epitopes of the Plasmodium falciparum circumsporozoite protein among field isolates is temporally stable: a 5-year longitudinal study in southern Vietnam.

In an effort to decipher the nature and extent of antigen polymorphisms of malaria parasites in a setting where malaria is hypomesoendemic, we conducted a 5-year longitudinal study (1998 to 2003) by sequencing the Th2R and Th3R epitopes of the circumsporozoite protein (CSP) of 142 Plasmodium falciparum field isolates from Bao Loc, Vietnam. Samples were collected during the high-transmission season, September through December 1998 (n = 43), as well as from July 2000 to August 2001 (n = 34), September 2001 to July 2002 (n = 33), and August 2002 to July 2003 (n = 32). Marked sequence diversity was noted during the high-transmission season in 1998, but no significant variation in allele frequencies was observed over the years (chi(2) = 70.003, degrees of freedom = 57, P = 0.116). The apparent temporal stability in allele frequency observed in this Bao Loc malaria setting may suggest that polymorphism in the Th2R and Th3R epitopes is not maintained by frequency-dependent immune selection. By including 36 isolates from Flores Island, Indonesia, and 19 isolates from Thaton, Myanmar, we investigated geographical patterns of sequence polymorphism for these epitopes in Southeast Asia; among the characterized isolates, a globally distributed variant appears to be predominant in Vietnam (75 of 142 isolates, or 52.8%) as well as in Myanmar (15 of 19 isolates, or 78.9%) and Indonesia (31 of 36 isolates, or 86.1%). Further analyses involving worldwide CSP sequences revealed distinct regional patterns, a finding which, together with the unique mutations observed here, may suggest a possible role for host or local factors in the generation of sequence diversity in the T-cell epitopes of CSP.

Animals↗

PubMed1993

Family functioning following adolescent substance abuse treatment.

Reciprocal influences of substance abuse and family functioning have been hypothesized from diverse theoretical perspectives. The longitudinal study presented here investigated the relationship between adolescent alcohol and drug use outcome and family functioning following adolescent substance abuse treatment. Consistent with predictions, long-term improving teens (n = 17) experienced better family relations, and less conflict-related behavior within the family, than did teens who returned to an abuse pattern of drug use (n = 37). Two years following treatment, families of improvers demonstrated greater cohesion and expressiveness, and less conflict, than did families of relapsers. Findings highlight a gradual process of adaptation in relations among families of teens treated for alcohol and drug abuse.

Adolescent↗

PubMed1999

Genetic diversity and mosaicism at the por locus of Neisseria gonorrhoeae.

The por genes of the predominant serovars of Neisseria gonorrhoeae circulating in a high-frequency transmitter core group located in Nairobi, Kenya, were examined for nucleotide sequence polymorphism. The level of por gene diversity did not differ significantly between core group-derived gonococcal strains and gonococcal strains originating elsewhere. However, por mosaicism appeared to be more frequent among core group-derived strains, suggesting that recombination of different por sequences may be a important strategy by which N. gonorrhoeae generates por gene diversity within core group populations. Despite extensive sequence variability, por expressed by gonococcal isolates of different geographic origin exhibited conserved patterns of nucleotide change, suggesting that diversity among por alleles may also be finite.

Base Sequence↗

PubMedDate not supplied

[Biographical factors and the experience of aging as perceived by single women and long-term widows].

The article deals with biographical factors of the perceived aging process in never-married women and long-time widows. A short survey is given on some aspects of these two forms of family status as it is reflected in the gerontological/social science literature. It is criticized that the situation of the married women was regarded as a taken-for-granted norm of female existence in old age for a long time while the majority of the so-called single women was looked upon as a deviant minority group. The need for a differenciated view of the single women's situation including biographical aspects is stressed. The empirically based analysis of the perceived life space of older women within the Bonn longitudinal study of aging proves the inadequacy of the label "single women" which seems to conceal the psychologically and sociologically interesting diversity within this social category: The perceived aging experience of the never-married women and the long-time widows of this sample is strongly influenced by biographical aspects and can be characterized by different patterns of aging representing distinct types of social categories.

Activities of Daily Living↗

PubMed2000

Cytoarchitectonic subdivisions in the subtectal midbrain of the lizard Gallotia galloti.

Contemporary study of molecular patterning in the vertebrate midbrain is handicapped by the lack of a complete topological map of the diverse neuronal complexes differentiated in this domain. The relatively less deformed reptilian midbrain was chosen for resolving this fundamental issue in a way that can be extrapolated to other tetrapods. The organization of midbrain centers was mapped topologically in terms of longitudinal columns and cellular strata on transverse, Nissl-stained sections in the lizard Gallotia galloti. Four columns extend along the whole length of the midbrain. In dorsoventral order: 1) the dorsal band contains the optic tectum, surrounded by three ventricularly prominent subdivisions, named griseum tectale, intermediate area and torus semicircularis, in rostrocaudal order; 2) a subjacent region is named here the lateral band, which forms the ventral margin of the alar plate and also shows three rostrocaudal divisions; 3) the basal band forms the basal plate or tegmentum proper; it appears subdivided into medial and lateral parts: the medial part contains the oculomotor and accessory efferent neurons and the medial basal part of the reticular formation, which includes the red nucleus rostrally; the lateral part contains the lateral basal reticular formation, and includes the substantia nigra caudally; 4) the median band contains the ventral tegmental area, representing the mesencephalic floor plate. The alar regions (dorsal and lateral) show an overall cellular stratification into periventricular, central and superficial strata, with characteristic cytoarchitecture for each part. The lateral band contains two well developed superficial nuclei, one of which is commonly misidentified as an isthmic formation. The basal longitudinal subdivisions are simpler and basically consist of periventricular and central strata.

Animals↗

PubMed2005

Menopause, physical activity, and body composition/fat distribution in midlife women.

PURPOSE: Hormonal changes associated with menopause, chronological aging, and lifestyle, specifically physical activity, may all influence the changes in body composition and fat distribution experienced by midlife women. This cross-sectional study examined those relations in a representative sample of 248 white and Chinese women, ages 47-57, participating in an ancillary study to the Study of Women's Health Across the Nation (SWAN), a multi-center, longitudinal investigation of the natural history of the menopause in a racially/ethnically diverse cohort. METHODS: Body composition (lean mass, percent body fat) was assessed with dual energy x-ray absorptiometry, and central adiposity was determined by waist circumference. Physical activity was assessed from 7 d of accelerometer recordings. Menopausal status was based on self-reported bleeding patterns. RESULTS: Higher levels of physical activity, particularly vigorous-intensity activity, were generally independently associated with decreased percent body fat and smaller waist circumference, although these findings were not statistically significant in the Chinese women. Among the white women, every half a standard deviation increase in total activity was associated with a 1.6-point decrease in percent body fat (P = 0.002). Waist circumference decreased from 96.2 cm (SE = 1.04) in those doing no vigorous-intensity activity to 81.4 cm (SE = 1.05) in those doing 10 min or more a day (P for trend = 0.05). For both the whites and the Chinese, late peri- and postmenopausal status was associated with lower lean mass, and among the Chinese, tended to be associated with higher percent body fat. CONCLUSION: These findings suggest that regular physical activity may help to mitigate the tendency for weight gain and adverse changes in body composition and fat distribution that accompany aging and the menopausal transition.

Body Composition↗

PubMed2006

EphA7 receptor is expressed differentially at chicken prosomeric boundaries.

We reexamined tyrosine-kinase receptor EphA7 RNA signal in embryonic chicken forebrain, to clarify its topographic relationships with early regionalization processes, such as establishment of prosomeric boundaries. After neurulation, uniform alar expression appears across prospective prosomeres prosomere 1, prosomere 2 and prosomere 3 (prethalamus, thalamus and pretectum). This pattern soon changes by differential downregulation at or in between some of the prosomeric boundaries in an individual pattern for each limit, and by expansion of expression into the rostral midbrain. The secondary distribution highlights various transversal and longitudinal domains, notably the zona limitans intrathalamica and the pretectum limits, as well as two longitudinal bands in the basal plate, termed paramedian and parabasal. Strong expression of EphA7 appears at the mammillary pouch and a supramammillary tegmental arch from stage Hamburger and Hamilton stages 14-15 onwards. At the end of the developmental period examined, expression of EphA7 in the ventricular zone decreases generally (with some exceptions) and novel expression domains start to appear in the mantle layer, initiating a third phase of differential expression. Thus, while the expression of EphA7 does not show a fixed functional or topographic relationship to prosomeric boundaries, sequential transcription changes during chicken development are consistent with a differential involvement of the diverse interprosomeric boundaries, as well as dorsoventral patterning organizers, in the regulation of EphA7 expression.

Animals↗

PubMed2000

The longitudinal course of bipolar disorder.

Course of illness is central to our focus on bipolar disorder due to the lifelong nature of this illness in the majority of patients. In this overview, we highlight areas of consensus and debate on factors that impact course of illness. Findings on age at onset, psychiatric comorbidity, frequency of episodes, cycle pattern, rapid cycling, mixed symptoms, and precipitants of episodes including use of substances and antidepressants and lithium discontinuation are discussed. The diversity and range of presentation and even course of illness become quickly apparent in this review. Highlighting these factors rather than seeking a unifying theory should be a productive way to refine our ability to identify additive factors contributing to course of illness for patients with bipolar disorder.

Age of Onset↗

PubMed2005

Temporal and spatial variation in age-specific net migration in the United States.

As fertility differences in the United States diminish, population redistribution trends are increasingly dependent on migration. This research used newly developed county-level age-specific net migration estimates for the 1990s, supplemented with longitudinal age-specific migration data spanning the prior 40 years, to ascertain whether there are clear longitudinal trends in age-specific net migration and to determine if there is spatial clustering in the migration patterns. The analysis confirmed the continuation into the 1990s of distinct net migration "signature patterns" for most types of counties, although there was temporal variation in the overall volume of migration across the five decades. A spatial autocorrelation analysis revealed large, geographically contiguous regions of net in-migration (in particular, Florida and the Southwest) and geographically contiguous regions of net out-migration (the Great Plains, in particular) that persisted over time. Yet the patterns of spatial concentration and fragmentation over time in these migration data demonstrate the relevance of this "neighborhood" approach to understanding spatiotemporal change in migration.

Adolescent↗

PubMed2001

Regional-scale assembly rules and biodiversity of coral reefs.

Tropical reef fishes and corals exhibit highly predictable patterns of taxonomic composition across the Indian and Pacific Oceans. Despite steep longitudinal and latitudinal gradients in total species richness, the composition of these key taxa is constrained within a remarkably narrow range of values. Regional-scale variation in reef biodiversity is best explained by large-scale patterns in the availability of shallow-water habitat. Once habitat area is accounted for, there is surprisingly little residual effect of latitude or longitude. Low-diversity regions are most vulnerable to human impacts such as global warming, underscoring the urgent need for integrated management at multinational scales.

Animals↗

PubMed2003

The burden and patterns of disability in activities of daily living among community-living older persons.

BACKGROUND: The onset of disability in activities of daily living (ADLs) is considered a sentinel event in the life of an older person, but recent evidence suggests that newly disabled elders have high rates of recovery. We performed a longitudinal study to determine the burden and patterns of ADL disability among previously nondisabled, community-living older persons. METHODS: We studied 754 community-living persons, aged 70 years or older, who were categorized into three groups according to their risk for disability (low, intermediate, high). Participants were interviewed each month for 2 years to determine the presence and severity of disability in four key ADLs: bathing, dressing, walking, or transferring. RESULTS: Among the 690 nondecedents, the rates of any disability were 17.7%, 48.7%, and 65.2%, respectively, for the low-, intermediate-, and high-risk groups. Whereas only 6.9% of nondecedents in the low-risk group had more than 1 month of disability, 38.2% and 50.6% of nondecedents in the intermediate- and high-risk groups (i.e., physically frail), respectively, had multiple months and/or episodes of disability. The patterns of disability were quite diverse, with no single pattern representing the disability experience of more than half the decedents or nondecedents in any of the risk groups. CONCLUSIONS: Disability among community-living older persons, particularly those who are physically frail, is a highly dynamic process with considerable diversity. Our results provide strong evidence to support an emerging paradigm of disability as a reversible, and often recurrent, event.

Activities of Daily Living↗

PubMed2026

Oral bacteriome in pediatric patients with malignancies prior to chemotherapy: a pilot study using full-length 16S rRNA sequencing.

OBJECTIVE: To characterize the composition, diversity, and ecological features of the oral bacteriome in pediatric patients with malignancies prior to chemotherapy initiation. METHODS: In this prospective pilot study,supragingival plaque samples were collected from 10 pediatric cancer patients prior to the initiation of chemotherapy. Bacterial genomic DNA was extracted from each sample, and the full-length 16S rRNA gene was amplified and sequenced on the PacBio Sequel II platform using circular consensus sequencing (CCS). Raw CCS reads were quality-filtered and denoised into amplicon sequence variants (ASVs) using DADA2, and taxonomic assignment was performed against the SILVA 138 reference database. Alpha diversity was assessed using the Chao1, Shannon, Simpson, and Faith's phylogenetic diversity (PD whole tree) indices, while beta diversity was evaluated through principal coordinate analysis (PCoA), and non-metric multidimensional scaling (NMDS). Microbial co-occurrence networks were constructed to characterize bacterial interactions, and functional potential was predicted using PICRUSt2, and BugBase. RESULTS: A total of 614,473 high-quality CCS reads were generated, yielding 1,697 ASVs. Alpha diversity analysis revealed substantial inter-individual variation in microbial richness and diversity among the pediatric cancer patients. The bacterial community was dominated by the phyla Firmicutes, Proteobacteria, Bacteroidota, Actinobacteriota. At the genus level, Streptococcus, Prevotella, Neisseria, and Haemophilus were the most abundant taxa. Beta diversity analysis revealed distinct clustering patterns, indicating highly individualized microbial profiles. Co-occurrence network analysis identified several keystone taxa and potential pathogenic associations within the supragingival plaque community. Functional prediction indicated that the dominant metabolic pathways were related to amino acid metabolism, carbohydrate metabolism, and membrane transport. CONCLUSION: These preliminary findings reveal a taxonomically diverse, highly individualized pre-chemotherapy oral bacteriome, providing foundational baseline profiles to guide future longitudinal investigations of chemotherapy-induced dysbiosis and personalized interventions.

Humans↗

PubMed2026

Pregnancy diet based on ancestral patterns increases growth in subcortical fetal brain regions.

Evidence on the biological basis for maternal nutrition effects on fetal and newborn neurodevelopment remains limited. This randomized controlled trial in Ecuador tested a maternal dietary pattern-derived from empirical studies of nutrition in human evolution and adapted locally-on offspring growth and brain development. Pregnant women (n = 215) in their first trimester were randomized to: 1) control (n = 104); or 2) Mikhuna ("nourish" in Kichwa) intervention (n = 111). The intervention, from 12 wk gestation to birth, consisted of a weekly food delivery (8 eggs, 500 g fish, and a variety of sustainably sourced fruits and vegetables) and a behavior change communication strategy encouraging diet diversity and limiting highly processed foods. Longitudinal data collection occurred at 12 wk, 21 wk, 35 wk gestation, and 2 wk postpartum, and included ultrasound imaging of fetal bone and brain parameters, maternal dietary intakes, anthropometry, socioeconomic and demographic variables, and other biomarkers. At close of intervention, a significantly higher percentage of women met the minimum dietary diversity threshold in Mikhuna (74.5%) vs. control groups (55.8%) (P = 0.004). Generalized linear regression models showed significant differences in Mikhuna compared to control for: corpus callosum length 0.19 cm (95% CI [0.02, 0.35]), gangliothalamic ovoid height 0.15 cm (95% CI [0.03 to 0.26]), and femur length -0.10 cm (95% CI [-0.19, -0.02]) from 21 wk to 35 wk; and corpus callosum Z 0.56 (95% CI [0.03, 1.09]) and femur length Z -0.21 (95% CI [-0.42, 0.00]) at 35 wk. The Mikhuna intervention increased the growth of subcortical fetal brain structures, which have established roles in motor control, cognition, and signal transmission.

Female↗

PubMed2004

HCV quasispecies evolution: association with progression to end-stage liver disease in hemophiliacs infected with HCV or HCV/HIV.

Patients with inherited bleeding disorders who received clotting factor concentrates before 1987 have high rates of hepatitis C virus (HCV) or HCV/HIV infection. We evaluated HCV quasispecies evolution in longitudinally collected specimens comparing those from patients with progression to end-stage liver disease (ESLD; cases) to those with compensated chronic hepatitis (controls). Plasma samples were obtained from the National Cancer Institute Multicenter Hemophilia Cohort Study. Controls were matched for age, sex, infection duration, and presence/absence of HIV. Samples from early infection were compared to those obtained after onset of ESLD in the cases. The first hypervariable (HVR1) and core proteincoding regions were amplified, subcloned, and sequenced. Complexity and diversity were determined. More than 700 sub-clones from 10 pairs of patients (8 with HIV) followed over approximately 9.3 years were evaluated. HVR1 complexity narrowed over time in the cases, whereas it increased in controls (P = .01). Similar trends were observed for diversity within HVR1 and the core region (P = .04). HCV-infected patients with inherited bleeding disorders undergo quasispecies evolution over time. Evolution patterns differ for progressors and nonprogressors. Further understanding of these mechanisms may help identify factors related to progression rate and treatment response.

Amino Acid Sequence↗