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The effect of dietary restriction of varying duration on survival, tumor patterns, immune function, and body temperature in B10C3F1 female mice.

Seven groups of mice were maintained on different dietary programs varying with respect to restriction at various stages of life. Restriction was associated with less age-related decline in T-dependent immunological function and a slight but significant lowering of body temperature. The best mean and maximum survival and the lowest late-life mortality rate was found in the group restricted throughout life, but restriction during any part of the lifespan enhanced survival to some degree. The mean life spans of tumor-bearing animals tended to be greater in restricted than in nonrestricted groups, corresponding to an age-decelerating effect. Tumor frequency varied with the period of life during which restriction took place and was not always decreased in restricted animals. These latter results suggest that the mechanisms whereby dietary restriction influences the aging rate and tumor susceptibility may not be entirely identical.

Animals↗

Spatial patterns in the fruiting bodies of the cellular slime mold Polysphondylium pallidum.

During morphogenesis in the slime mold Polysphondylium pallidum cell masses are periodically pinched off from the base of the developing sorogen. These masses round up and differentiate into secondary sorogens, which become radially ordered arrays of secondary fruiting bodies called whorls. Here we describe the morphogenesis of P. pallidum and characterize the spacing of whorls along the central stalk of the fruiting body and the spacing of sorocarps within whorls. We find both are highly regular. We propose that the linear spacing of whorls can be accounted for satisfactorily by a model that views the periodic release of cell masses from the base of the developing sorogen as the consequence of an imbalance between forces that orient amoebae toward the tip of the culminating sorogen, and cohesive forces between randomly moving cells in the basal region of the sorogen, which act as a retarding force. The orderly arrangement of fruiting bodies within whorls can be explained most easily by models that employ short-range activation and lateral inhibition.

Cell Differentiation↗

Different patterns of intraerythrocytic inclusion body distribution in the two types of haemoglobin H disease. An ultrastructural study.

Electron microscopic examination of intraerythrocytic inclusion bodies induced by methylene blue was carried out in 7 non-splenectomized patients with haemoglobin (Hb) H disease. In classical Hb H disease with the genotype of alpha-thalassaemia 1/alpha-thalassaemia 2 the inclusion bodies were mostly membrane-associated. In contrast, in Hb H disease of alpha-thalassaemia 1/Hb Constant Spring genotype the majority of inclusion bodies were in a floating stage. Possible mechanisms for the unexpected difference are discussed.

Erythrocyte Inclusions↗

Role of nitric oxide in the development of retinal projections.

Synthesis of nitric oxide (NO) occurs downstream from activation of NMDA receptors and NO acts as a retrograde messenger, influencing the refinement and stabilization of coactive afferent terminals. Cells and neuropil in the rat superior colliculus (SC) and lateral geniculate body (LGB) show intense, developmentally regulated activity for NO synthase (NOS). To study the role of NO in the development of retinogeniculate and retinotectal axon arbors, we examined primary visual projections of rats that had received daily i.p. injections of L-NoArg (an NOS inhibitor) for 4-6 weeks starting from postnatal day 0. Retinal fibers labeled by intraocular injection of the B subunit of cholera toxin were revealed immunohistochemically and the density of fibers in the superficial SC and in the dorsal LGB was measured by computerized image analysis. Single retinocollicular terminal arbors were reconstructed at the computer (Neurolucida). Treated rats showed significant alterations in ipsilateral retinotectal projections, in the mediolateral and anteroposterior axes: there was an increase in the density of fibers entering the SC, in branch length, and in numbers of boutons on retinotectal arbors in the treated group. Ipsilaterally projecting retinal axons also showed an increase in density and distribution in the dorsal nucleus of the LGB. If animals were allowed to survive for several months after stopping treatment, similar changes were also noted, but these were much less striking. Our results suggest that, in the mammalian visual system, NO released from target neurons in the SC and LGB serves as a retrograde signal which feeds back on retinal afferents, influencing their growth.

Aging↗

Hydrotechnical facilities within the Chernobyl nuclear power plant exclusion zone: impacts on hydrologic regime and plant growth patterns of floodplain water bodies of the Pripyat River.

As result of the Chernobyl nuclear power plant accident the territory of the left-bank flood-lands of the Pripyat River have undergone intensive radionuclide contamination. With the purpose of preventing the washing away of radioactive substances, a complex of flood protection dams was constructed. This construction changed the hydrological regime of these territories and caused overgrowth by higher aquatic plants. Absence of a flowing mode of reservoirs, the stagnant phenomena during spring and seasonal high waters on the embank site have caused amplification of eutrophication processes, swamping and, connected with it, increase of water-marsh floristic complex in the structure of the vegetative cover.

Ecosystem↗

Chronic-persistent hepatitis and pregnancy.

The course and possible risks of pregnancy in 7 women between the ages of 20 and 30 yr with chronic-persistent hepatitis (CPH) were evaluated. Ten pregnancies occurred in these women during the follow-up period which ranged from 3 to 8 yr. Four of the fetuses were aborted electively for nonmedical reasons. The other six pregnancies resulted in normal spontaneous vaginal deliveries at term. Each of the women experienced uneventful pre- and postnatal courses, and the neonates were all healthy and developmentally normal at birth. There was no biochemical or clinical evidence to suggest worsening liver disease during pregnancy. Normal menstrual patterns when not pregnant and normal biphasic basal body temperature patterns in 4 women suggested that ovulation and fertility were not impaired significantly. Pregnancy in women with CPH appears safe to both mother and fetus alike. This finding contrasts with the morbidity and mortality some authors have found to be associated with cirrhosis and with portal hypertension. We speculate that our findings may be relevant to women with other portal lesions resembling CPH such as resolving acute hepatitis and chronic active hepatitis in sustained remission.

Chronic Disease↗

Q-wave infarction: pathophysiology of body surface potential map and ventriculographic patterns in anterior and inferior groups.

To define and relate the body surface electrocardiographic and left ventricular wall motion patterns in the acute phase of Q-wave infarction, we recorded 120-lead body surface potential maps and radionuclear angiograms in 29 patients on the fifth day of their first infarction. By standard 12-lead electrocardiographic criteria, 17 patients were designated as anterior infarction and 12 as inferior infarction. Body surface map infarct patterns in the anterior group were characterized primarily by abnormal Q-wave, negative Q-zone and positive ST-segment integral patterns over the anterior torso and little reciprocal change. The maps of the inferior patient group were characterized primarily by depolarization and repolarization infarct patterns over the inferior torso and marked reciprocal changes in all integral patterns over the anterior torso. Both groups displayed infarct patterns over a common area of the right anterior-inferior torso. In the anterior group depolarization minima and repolarization maxima were clustered in a small precordial area; in the inferior group the same extrema were widely scattered over the inferior torso, both anteriorly and posteriorly. Segmental left ventricular wall motion analysis revealed that the 3 most commonly and most severely involved segments were the same in both infarct groups--apical, infero-apical and antero-lateral. Basal septum and antero-basal segmental dysfunction were exclusive to the anterior group; postero-lateral and infero-basal involvement, to the inferior group.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗

Body mass index and fat patterning as correlates of lipids and hypertension in an elderly, biracial population.

BACKGROUND: Associations between anthropometric measurements of fat patterning and risk factors for cardiovascular disease have been demonstrated in several populations composed predominantly of White, young or middle-aged adults. Fat pattern changes with aging and older adults tend to have a more central or abdominal fat distribution. Few investigators have focused on relationships of fat patterning with plasma lipids or blood pressure in older adults or in Blacks. METHODS: Body mass index (BMI), fat patterning, plasma lipids, and blood pressure were examined in participants of the Charleston Heart Study. Subjects included 216 White men, 95 Black men, 320 White women, and 155 Black women with a mean age of 72.7 years (range 61-106). RESULTS: In each of the four race and gender groups, BMI was inversely correlated with HDL cholesterol and positively correlated with hypertension. BMI tended to be positively associated with total cholesterol, although the relationships were not statistically significant. After controlling for the effects of BMI, age, smoking, and alcohol intake (using regression analysis), waist to hip ratio was associated with cholesterol levels in the White men and women and the Black men. In similar models, waist circumference in Black women was inversely associated with HDL. There were no significant relationships between waist to hip ratio and hypertension in any of the groups after controlling for BMI. CONCLUSION: In an elderly cohort, waist to hip ratio was associated with plasma lipids, but not with hypertension, when the effects of BMI were held constant.

Adipose Tissue↗

Vertebral-body collapse in focal and diffuse disease: patterns of pathologic processes.

The radiographic patterns of vertebral-body collapse and/or endplate deformity were examined in 99 autopsy specimens of the thoracolumbar spine with benign and malignant disease. Angling of endplates was found to be highly predictive of underlying malignancy, whereas concavity was more suggestive of benign disease, for both individual vertebral bodies and intact spines (P less than .001). Diffuse-concave, diffuse-angled, and focal-angled patterns were more useful (P less than .001) than the focal-concave pattern (P = .07) in distinguishing between benign and malignant disease for superior endplates, whereas all were equally useful (P less than .025) in inferior endplates. Condition of the adjacent disks, location within the spine, and position of the apex of collapse were not predictive. Although these results and subsequent blinded testing suggest that reliable distinction between benign and malignant vertebral collapse is possible, extrapolation to clinical practice may be inappropriate because of population bias in the study and differences in radiographic quality between autopsy specimens and live subjects.

Adult↗

Melatonin implants disrupt developmental synchrony regulated by flexible interval timers.

Siberian hamsters born into short daylengths near the end of the breeding season are reproductively inhibited from birth and delay gonadal maturation until the following spring. This vernal transition to a reproductive phenotype coincides with an abrupt increase in body weight, and both processes are triggered by an interval timing mechanism that becomes insensitive, or refractory, to short-day inhibition. It was previously demonstrated that hamsters born into simulated natural photoperiods in early August became photorefractory at later ages than hamsters born into September photoperiods. As a consequence of flexibility in the duration programmed by the interval timer, development of seasonal birth cohorts was synchronous with respect to the calendar date simulated by laboratory photoperiod. In the present study, hamsters were born into simulated August or September photoperiods. Hamsters from each cohort were given removable constant release melatonin implants to reversibly obscure the neuroendocrine representation of daylength between 3 and 9 weeks or 9-15 weeks of age. When control hamsters were given beeswax capsules throughout, August-born males were approximately 6 weeks older than September males at the onset of photorefractoriness as assessed by accelerated increases in body weight and testicular size. Females exhibited the same pattern in body weight. These measures were synchronized with respect to calendar date. Synchronization of cohorts was disrupted by melatonin capsules from 3-9 weeks of age but not by later implants. Melatonin implants altered synchronization by influencing the developmental trajectory of September-born hamsters without influencing the August cohort. These results demonstrate that the function of the interval timer underlying photorefractoriness is influenced by photoperiod and by melatonin. The endogenous pattern of melatonin signals adjusts the duration measured by the interval timer to insure that developmental milestones of seasonal cohorts are synchronized with environmental conditions.

Animals↗

Asymmetric expression of the BMP antagonists chordin and gremlin in the sea anemone Nematostella vectensis: implications for the evolution of axial patterning.

The evolutionary origin of the anterior-posterior and the dorsoventral body axes of Bilateria is a long-standing question. It is unclear how the main body axis of Cnidaria, the sister group to the Bilateria, is related to the two body axes of Bilateria. The conserved antagonism between two secreted factors, BMP2/4 (Dpp in Drosophila) and its antagonist Chordin (Short gastrulation in Drosophila) is a crucial component in the establishment of the dorsoventral body axis of Bilateria and could therefore provide important insight into the evolutionary origin of bilaterian axes. Here, we cloned and characterized two BMP ligands, dpp and GDF5-like as well as two secreted antagonists, chordin and gremlin, from the basal cnidarian Nematostella vectensis. Injection experiments in zebrafish show that the ventralizing activity of NvDpp mRNA is counteracted by NvGremlin and NvChordin, suggesting that Gremlin and Chordin proteins can function as endogenous antagonists of NvDpp. Expression analysis during embryonic and larval development of Nematostella reveals asymmetric expression of all four genes along both the oral-aboral body axis and along an axis perpendicular to this one, the directive axis. Unexpectedly, NvDpp and NvChordin show complex and overlapping expression on the same side of the embryo, whereas NvGDF5-like and NvGremlin are both expressed on the opposite side. Yet, the two pairs of ligands and antagonists only partially overlap, suggesting complex gradients of BMP activity along the directive axis but also along the oral-aboral axis. We conclude that a molecular interaction between BMP-like molecules and their secreted antagonists was already employed in the common ancestor of Cnidaria and Bilateria to create axial asymmetries, but that there is no simple relationship between the oral-aboral body axis of Nematostella and one particular body axis of Bilateria.

Amino Acid Sequence↗