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PubMed1983

[Aging and development, growth and spreading of cancer].

In spite of steep elevation of cancer mortality in the aged, it has been believed that ageing reduces susceptibility to carcinogens. Ebbesen, however, presented contradictory result recently. We examined influences of ageing on chemical carcinogenesis using 6 different age groups of rats given N-bis (2-hydroxypropyl) nitrosamine (DHPN). The results suggested (1) susceptibility to initiating process did not differ much, but promoting process might be prolonged in aged rats, and (2) susceptibility difference was enlarged in aged individuals. These data were supported by doubling time of lung tumors. Another evidence suggesting retarded tumor growth in the aged was observed in frequency of organ metastasis of gastric cancer. The conspicuous finding was shown in the number of cases of gastric cancer without any organ metastasis, i.e. 42.3% in the aged male and 9.3% in the younger male. Occurrence of lymphangitis carcinomatosa in the lung also showed distinct difference between the aged and the younger groups. This type of metastasis mostly derived from gastric cancer, especially signet ring cell cancer. Degree of differentiation of developed tumor may be another point of consideration to estimate the age dependency of tumor metastasis. We also have to pay some attention to the cancers increasing with age.

Aged↗
PubMed1994

Changes in the microvascular network during cardiac growth, development, and aging.

Quantitative changes in the terminal vascular bed of the mammalian heart were assessed during postnatal development and aging. The most striking feature is a considerable formation of new capillaries in the early postnatal period, accompanied by a moderate formation of new arterioles. On the other hand, coronary arterioles seem to disappear at a higher rate than capillaries in the senescent heart. We proposed a three-dimensional structural model of tissue capillary supply, defined as capillary domain area times capillary segment length. This so called capillary supply unit increases as a function of age and body growth. It is very similar in size and shape (length to width ratio) to cardiac myocytes.

Adult↗
PubMed1999

Growth, development, and physical fitness of Flemish vegetarian children, adolescents, and young adults.

This study was designed to assess average daily dietary intakes of energy in 82 vegetarian children (group A: 6- 9-y-old girls and 6-11-y-old boys), adolescents (group B: 10- 15-y-old girls and 12-17-y-old boys), and young adults (group C: 16-30-y-old females and 18-30-y-old males) and included determination of height and weight; triceps, suprailiac, and calf skinfold thicknesses; puberty ratings; and physical fitness. Dietary energy intake was lower than recommended values in all 3 groups. Height and weight did not differ significantly from the reference data except in group B, which had significantly lower heights and weights and lower body mass indexes (P<0.05). Triceps and suprailiac skinfold thicknesses were lower in all age groups, whereas the calf skinfold thickness was only significantly lower in the 10-15-y-old girls (P<0.05). The vegetarian children were as physically fit as the reference group. The vegetarian adolescent boys and girls and the young adults scored significantly lower on the standing long jump and 30-s sit-up (P<0.05). The vegetarian subjects of groups B and C recovered significantly faster from the step test (P<0.05). Puberty ratings plotted on percentile graphs showed that all vegetarian subjects, except for 1 girl, were within the normal developmental range. We conclude that, within the limits of this study, vegetarian subjects have lower relative body weights and skinfold thicknesses in adolescence than do nonvegetarians. They scored lower on the strength tests and better on the cardiorespiratory test when compared with reference values. The growth and maturation status of the vegetarian population were within the normal range.

Adolescent↗
PubMed1967

The influence of simulated low-gravity environments on growth, development and metabolism of plants.

Low-gravity environments may be simulated through appropriate horizontal clinostat rotation. This simulation is accomplished through a biological nullification of the directional component of gravitational force. Measuring biologically effective gravity force by organ response, it is readily demonstrated that biologically active gravitational force may be treated as a two-dimensional vector. Though the magnitude dimension of this vector remains virtually constant anywhere on earth, the biologically effective direction dimension may be quantitatively altered by clinostat rotation, provided appropriate angular velocities and angles of inclination of clinostat axes are employed. Using oat seedlings, a rotation rate of 2 rpm, and a horizontal axis clinostat, a 'zero g' environment may be simulated. This simulated 'zero g' condition is attested by the inability of plants to perceive unidirectional gravitational force of sufficient magnitude to elicit directional growth. Under such conditions, plants will grow in the direction imparted by the initial orientation of the plants in the system. Geotropic curvature responses to subsequent geostimulation are, however, greater in seedlings grown under these conditions, nullifying the direction dimension of gravitational force, than in seedlings grown with rotation but with normal unidirectional gravity loads. Root growth under simulated 'zero' gravity conditions is likewise enhanced as compared to plants grown with rotation but normal unidirectional gravity. These differences in magnitude of growth and response to subsequent geostimulation are inexplicable on bases of modified auxin economy or production. Respiration rates are, however, materially enhanced by the simulated 'zero g' environments. This enhancement of respiration, as well as growth, quantitatively diminishes as the unidirectional gravity load is increased. These results imply that the primary effect of low-gravity environments is likely that of modifying the magnitude of respiratory metabolism. Such a modification is partly or wholly explicable on a basis of a modified distribution pattern of metabolically active particulate cell inclusions.

Avena↗
PubMed2006

Growth, development, and failure to thrive: factors that underlie the availability of pediatric critical care facilities in the United States.

OBJECTIVE: Pediatric intensive care units (PICUs) have grown in number and size over time in aggregate across the United States, but the factors promoting such changes have not been well characterized. This study was conducted to explore the establishment, expansion, and closure of PICUs. DESIGN: A cross-sectional in-depth telephone interview survey of executive hospital administrators. SETTING: Fourteen institutions representing four newly established PICUs, two PICU expansions, and eight PICU closures. MEASUREMENTS AND MAIN RESULTS: Officials' comments indicate that the establishment of PICUs is driven primarily by the need to care for patients requiring intensive cardiorespiratory monitoring and/or postoperative surgical care and to respond to the needs of outlying community hospitals. The main factors that drive PICU expansion are institutional growth in pediatric subspecialist medical and surgical support for critically ill patients and the need to match increases in demand and patient volume experienced by existing PICUs. With regard to PICU closures, competition from other institutions within the same market for patients and subspecialty care providers, lower-than-expected volumes of patients, and/or negative financial margins were cited as key factors. CONCLUSIONS: This study provides new insight into decision-making that influences the availability of critical care services for children. The establishment, expansion, and closure of PICUs are driven predominantly by local demand for pediatric critical care services, whereas availability of subspecialists as well as competition between PICUs within the same market affect the long-term sustainability of such services.

Child↗
PubMed1982

Neuroendocrine pacemaker for growth, development and ageing.

The hypothesis is formulated that ageing is mediated through alteration in a pacemaker system located in the hypothalamus and dependent on serotonin-thyroid hormone interactions. Data in support of this hypothesis include: imbalance in central nervous system (CNS) neurotransmitters with ageing, with serotonin dominance; impairment of hypothalamic neurosecretion; increased heterogeneity of thyrotropin forms secreted from the aged pituitary; and drug and dietary manipulation of CNS serotonin with consequent effects on endocrine function and homeostasis.

Aging↗
PubMed1999

The sucrose-cleaving enzymes of plants are crucial for development, growth and carbon partitioning.

Sink organs of most plant species are supplied with carbon and energy in the form of sucrose. The channeling of sucrose into sink metabolism requires its cleavage by several isoforms of invertase and sucrose synthase, which are localized in different subcellular compartments. These activities regulate the entry of sucrose into distinct biochemical pathways, such as respiration or biosynthesis of cell wall polysaccharides and storage reserves. Other vital roles for the sucrose-cleaving enzymes include invertase activity at the site of phloem unloading and vacuolar invertase and sucrose synthase in sink organs, which drives the long-distance transport of sucrose. In addition, invertases have been implicated in the defense response and in turgor-driven cell expansion, and sucrose synthase expression is associated with low temperature and anaerobiosis responses. Finally, because sugars also regulate gene expression, the sucrose-cleaving enzymes play a fundamental role in controlling cell differentiation and development.

Journal Article↗
PubMed1988

Effects of postnatal DES treatment on uterine growth, development, and estrogen receptor levels.

The neonatal rodent appears to be an appropriate animal model for estrogen toxicity in the developing reproductive tract. Newborn rats were treated with diethylstilbestrol (DES) at human therapeutic doses (approx 1 mg/kg) during two ontogenetic periods (postnatal days 1-5 and 1-25). Treatment on days 1-5 doubled uterine wt by day 5; however, these uteri failed to grow after discontinuation of DES treatment. In contrast, uterine wt was 4-fold higher and DNA content was 2-fold higher than controls on days 10-25 with continued DES treatment. Total uterine estrogen receptor levels, depressed 60% by day 5 of DES treatment, partially recovered after discontinuation of DES treatment but remained 25% below controls on day 25. Receptor levels following DES on days 1-25 decreased to about 15% of the controls by day 15. Short-term DES treatment approximately halved uterine gland content while continued treatment almost completely inhibited gland appearance. DES effects on glands appear related to continued hypertrophy of the luminal epithelium, from which uterine glands are derived. Subsequent failure of uterine growth caused by DES treatment on days 1-5 is similar to clinical findings of hypoplastic uteri in DES-treated patients. Disruption of the normal ontogenetic patterns of estrogen receptor by DES may be involved. These data demonstrate abnormal patterns of growth, estrogen receptor levels and morphogenesis in uteri of rats treated postnatally with DES.

Age Factors↗
PubMed1996

[Influence of growth development inhibitors on the reproduction of Musca domestica (Diptera: Muscidae)].

An experiment with a strain of Musca domestica susceptible to insecticides and treated with different doses of 2 insects' development inhibitors: Juvenon and S-31183, was carried out. These compounds were added to food supplied to third-stage larvae. On calculating dosage-mortality lines, it was found a greater biological activity in S-31183. Those surviving DL90 were selected for fecundity and fertility studies. The following crossings were carried out: treated females x treated males, treated females x untreated males, untreated females x treated males, untreated females x untreated males (control group). In both compounds it was observed a remarkable reduction in the production and eclosion of eggs, on comparing the first three crossings with the control group. As regards fecundity, sex influences were not observed, whereas fertility was more affected by treated females. No differences were found in connection with the survival of all types of crossings. Morphological affectations are reported in pupae and adults.

Animals↗
PubMed1976

Growth, development and activity in rat offspring following maternal drug exposure.

Seventy-nine Sprague-Dawley derived primimparous rats were injected subcutaneously throughout pregnancy and the nursing period with either (1) 30 mg/kg of pure nicotine, (2) 5.0 mg/kg methamphetamine HCL, (3) saline vehicle, or, (4) non-injected. Vital and developmental measures were taken on the offspring throughout the nursing period and for one additional week. Metamphetamine-injected females had a shorter, and nicotine-injected females a longer gestational period, and both gained less weight over the 21-day period than the control groups. The pups of methamphetamine and nicotine dams were significantly underweight at birth and the 28 day postnatal period and exhibited developmental delay. Male offspring were divided into behavioral, aging, and autopsy on Day 28. Male offspring of methamphetamine-injected dams remained significantly lighter in weight for the first 15 months of life (aging groups). Their counterparts in the behavioral groups and the offspring of non-injected dams exhibited significantly greater activity for eight of the first twelve monthly assessments which began at 90 days of age. Additional vital, performance, and sensory measures will continue throughout the lifespan of the animals.

Aging↗
PubMed1999

Longitudinal assessment of adaptive and maladaptive behaviors in fragile X males: growth, development, and profiles.

As young fully mutated fragile X [fra(X)] males age, cognitive levels (IQ scores) and adaptive behavior levels (DQ scores) decline. Given the variable behavioral profiles reported previously, we wondered whether changes in specific attributes of adaptive behavior are related to declines in composite adaptive behavior levels. We also examined maladaptive behavior to determine if changes are related to age. Therefore, we evaluated three areas of adaptive behavior, as well as maladaptive behavior, in 28 fully mutated fra(X) males, ages 4-14 years. To develop a profile of adaptive behavior, we analyzed nine subscale scores from the Vine-land Adaptive Behavior Scale (VABS). To assess maladaptive behavior, we graded part I of the VABS Maladaptive Behavior Scale. Subjects were sorted into three age cohorts, according to their initial test age: younger than 6 years; 6 to 9 years; older than 9 years. Results indicate that, in all age groups, the communications domain is the most severely impacted compared with either the socialization domain or daily living skills and that, in all age groups, the socialization domain is a relative strength compared with either the communications domain or daily living skills. The youngest cohort manifested significant increases in age-equivalent community living skills. Significant differences in age-equivalent scores between cohorts were observed in written language and play skills. Maladaptive behavior scores were available from cross-sectional data only. Twenty males (74%) showed significantly higher maladaptive scores than expected from other children their age. Our data analysis also revealed a moderate and significant negative correlation between maladaptive behavior levels and age (r = -0.54; P < 0.01). Curiously, adaptive and maladaptive behaviors did not correlate with each other.

Adaptation, Psychological↗
PubMed2002

Regulation of cell size in growth, development and human disease: PI3K, PKB and S6K.

It has generally been observed that cells grow to a certain size before they divide. In the last few years, the PI3K signal transduction pathway has emerged as one of the main signaling routes utilized by cells to control their increase in size. Here we focus on two components of this pathway, PKB and S6K, and briefly review the experiments that initially uncovered their roles in cell size control. In addition, we discuss a number of recent observations suggesting that the generic models used to describe this pathway to date may have been oversimplified. Indeed, recent observations in Drosophila and mouse support a more complex interaction between these signaling components in development. Finally, we have utilized two contemporary studies involving PKB- and S6K-deficient mice as a paradigm to underscore the importance of cell size and to accurately delineate the connections between signaling pathways for human disease, such as diabetes mellitus.

Animals↗
PubMed1985

Measures of growth, development, and sexual maturation in mongolian gerbils (Meriones unguiculatus): effects of photic period during ontogeny.

We examined, in Mongolian gerbils, the adequacy of two commonly used indices of rate of development, age at eye-opening and age at vaginal introitus, as predictors of biologically important events: initiation of feeding on solid food and age at first parturition. We then enquired as to the interrelationships among body weight, eye-opening, and vaginal introitus in Mongolian gerbils whose rates of development were manipulated by altering the extent of their exposure to illumination during ontogeny. We found that (1) age at vaginal introitus was significantly, but weakly, correlated with age at first parturition (Experiment I); (2) age at eye-opening strongly predicted age of initiation of gnawing on solid food (Experiment II); (3) eye-opening occurred at markedly different ages, but at the same body weight in gerbils reared under 0/24-, 6/18-, 12/12-, and 24/0-hr day-night cycles (Experiment III); and (4) vaginal introitus occurred at both different ages and different body weights in females reared under different day-night cycles (Experiment III).

Animals↗
PubMed1989

Infectivity, growth, development and pathology of Echinostoma caproni (Trematoda) in the golden hamster.

Laboratory hamsters (Mesocricetus auratus) were experimentally infected with 75 +/- 15 metacercarial cysts of Echinostoma caproni. Worms were recovered from days 7 to 89 post-infection with eight to 90 (average 37) parasites in the small intestine. Worm wet weights averaged 0.85 mg at 10 days, 1.8 mg at 17 days, 3.4 mg at 45 days, and 7.7 mg at 89 days; average dry weights for the identical days were, 0.15, 0.30, 0.70 and 2.2 mg, respectively. The average body area of worms fixed in hot (80 degrees C) alcohol-formalin-acetic acid was 0.21 mm2 on day 3, 4.9 mm2 on day 10, and 17.7 mm2 on day 42. Clinical signs in some hamsters included progressive unthriftiness and watery diarrhea. Gross examination revealed enlarged lymphatic nodules along the length of the small intestine. The histopathological responses of hamsters to the parasite showed erosion of the intestinal villi with lymphocytic infiltration being the primary response; hemorrhagic areas were also observed in the villi.

Animals↗