A rat model of neurobehavioral development.

The neurobehavioral evolution of the normally growing rat has been investigated by means of a series of reflex, motor and sensory tests from birth up to weaning. A sequential development of behavioral responses has been assessed over this 21-days period, and 2nd week following birth representing an important step in the neurobehavioral maturation of the rat. This rat model may be considered as an useful reference to evaluate changes that may be induced by pharmacological and toxicological agents in the developing exposed rat.     

Mental processes and disorders: A neurobehavioral perspective in human biometeorology

Summary Research concerning the complex relation between weather and psychological processes has emphasized three important issues: methodological problems, the determination of the major behavioral factors, and the isolation of neurobiological mechanisms. This paper reviews the current status of each issue. Weather changes are most frequently associated with behaviors that are the endpoints of inferred psychological processes that include mood, subclinical pain, anxiety, and the correlates of schedule shifts. Learning and conditioning appear to mediate a powerful influence over weather-related responses. This may explain the large individual variability in these behaviors. The most well-known group effects associated with weather changes involve psychiatric populations. Clinical subpopulations may respond in different ways to different aspects of the same weather system as well as to different types of air masses. Likely neurobiological mechanisms through which meteorogenic stimuli may mediate whole organismic effects include the locus coeruleal and limbic systems. Expected psychobiological consequences are examined in detail. The magnitude and temporal-spatial characteristics of weather effects indicate they are the subject matter of behavioral epidemiology.     

Abnormal development of cultured rat embryos in rat and human sera prepared after vitamin A ingestion

Summary Human and rat sera were assayed for teratogenic activity using a whole rat embryo culture technique. Sera prepared from blood withdrawn 1–5 h after the ingestion of vitamin A capsules caused developmental retardation and craniofacial abnormalities. Control sera permitted normal growth and differentiation.Financial support for this project was provided by Department of Energy contract EVO 3139 (Office of Health and Environmental Research), USA (Scientific contribution 940, Storrs Agricultural Experiment Station), and by the Medical Research Council, U.K.     

Gliogenesis during embryonic development in the rat

Summary With the aid of thymidine-H³ autoradiography gliogenesis in the rat brain was seen to start during embryonic stages, which might continue into the postnatal stages of development. Gliogenesis followed a caudo-rostral gradient closely following neurogenesis. Ependymogenesis was found to occur in parallel with gliogenesis.Supported by research grants NS-08817 and CA-14650 from N.I.H.     

Gliogenesis during embryonic development in the rat

With the aid of thymidine-H3 autoradiography gliogenesis in the rat brain was seen to start during embryonic stages, which might continue into the postnatal stages of development. Gliogenesis followed a caudo-rostral gradient closely following neurogenesis. Ependymogenesis was found to occur in parallel with gliogenesis.     

A relevant in vitro rat model for the evaluation of blood-brain barrier translocation of nanoparticles

Poly(MePEG₂₀₀₀cyanoacrylate-co-hexadecylcyanoacrylate) (PEG-PHDCA) nanoparticles have demonstrated their capacity to reach the rat central nervous system after intravenous injection. For insight into the transport of colloidal systems across the blood-brain barrier (BBB), we developed a relevant in vitro rat BBB model consisting of a coculture of rat brain endothelial cells (RBECs) and rat astrocytes. The RBECs used in our model displayed and retained structural characteristics of brain endothelial cells, such as expression of P-glycoprotein, occludin and ZO-1, and immunofluorescence studies showed the specific localization of occludin and ZO1. The high values of transendothelial electrical resistance and low permeability coefficients of marker molecules demonstrated the functionality of this model. The comparative passage of polyhexadecylcyanoacrylate and PEG-PHDCA nanoparticles through this model was investigated, showing a higher passage of PEGylated nanoparticles, presumably by endocytosis. This result was confirmed by confocal microscopy. Thanks to a good in vitro/in vivo correlation, this rat BBB model will help in understanding the mechanisms of nanoparticle translocation and in designing new types of colloidal carriers as brain delivery systems.Received 4 March 2005; accepted 14 April 2005     

Pulmonary di-and-triacylglycerols during the perinatal development of the rat

Summary Diacylglycerol (DG) and triacylglycerol (TG) levels in rat lung tissue were determined from day 17 of gestation to day 10 post partum and studied in parallel with ultrastructural differentiation. The DG level, although rather low at all measured stages, rose significantly between days 17 and 19 and at birth. TG level increased steadily during the whole studied period and especially between days 17 and 19 and at birth. In DG as well as in TG, saturated fatty acids were predominant. The rising of TG levels paralleled the appearance and accumulation of lipid vacuoles in mesodermal cells lying in contact with type II cells. The possible role of these cells is discussed.     

Calmodulin in epithelial intestinal cells during rat development

Summary Calmodulin was immunocytochemically localized in the brush borders of rat intestinal epithelial cells from the tip to the base of the villi, from day 18 of fetal life up to the adult stage. The early (14th day) fetal cells, like the adult crypt cells, were not immunoreactive, although their calmodulin content was equal to that of the mature cells from the tips of the villi.     

Calmodulin in epithelial intestinal cells during rat development

Calmodulin was immunocytochemically localized in the brush borders of rat intestinal epithelial cells from the tip to the base of the villi, from day 18 of fetal life up to the adult stage. The early (14th day) fetal cells, like the adult crypt cells, were not immunoreactive, although their calmodulin content was equal to that of the mature cells from the tips of the villi.     

A model for testing the effect of drugs on the regeneration of spermatogenesis in the rat

Zusammenfassung Methode als Modell zur Prüfung der Wirkung von Pharmaka auf die Regeneration der Spermatogenese bei der Ratte.     

The effect of methaqualone on prenatal development in the rat

Methaqualone treatment of pregnant rats in doses of 100-200 mg/kg day produces resorption and a series of anomalies whose incidence increases with the dose-level employed.     

The effect of methaqualone on prenatal development in the rat

Summary Methaqualone treatment of pregnant rats in doses of 100–200 mg/kg day produces resorption and a series of anomalies whose incidence increases with the dose-level employed.Acknowledgment. Supported by the National Research Council of Canada, grant No. A0292. Methaqualone was generously supplied by W. H. Rorer, Canada, Ltd.     

Water intake: Influence on development of rat saline hypertension

Résumé Après 7 semaines de surcharge saline administrée par gavage, l'augmentation de tension artérielle systolique de 3 groupes de rats uninephrectomisés soumis à différents régimes d'hydratation s'avéra être en meilleure corrélation avec le rapport NaCl/H20 ingéré qu'avec la quantité absolue de sodium ingéré. La soif pourrait possiblement potentialiser d'autres formes d'hypertension expérimentale.     

In vitro development of rat embryos obtained from diabetic mothers

Rat embryos of 9.5 or 10 days of gestation were removed from control or streptozotocin-diabetic mothers and cultured in normal rat serum (180 mg% glucose) or in diabetic serum (600 mg% glucose). The development of control embryos in normal serum was adequate. Embryos from normal mothers cultured in diabetic serum showed signs of developmental retardation. The development of embryos obtained from diabetic mothers was severely impaired, regardless of the gestational age or the culture medium. These results suggest that a diabetic maternal milieu produces irreversible effects in the embryo very early in gestation.     

Mental processes and disorders: a neurobehavioral perspective in human biometeorology

Research concerning the complex relation between weather and psychological processes has emphasized three important issues: methodological problems, the determination of the major behavioral factors, and the isolation of neurobiological mechanisms. This paper reviews the current status of each issue. Weather changes are most frequently associated with behaviors that are the endpoints of inferred psychological processes that include mood, subclinical pain, anxiety, and the correlates of schedule shifts. Learning and conditioning appear to mediate a powerful influence over weather-related responses. This may explain the large individual variability in these behaviors. The most well-known group effects associated with weather changes involve psychiatric populations. Clinical subpopulations may respond in different ways to different aspects of the same weather system as well as to different types of air masses. Likely neurobiological mechanisms through which meteorogenic stimuli may mediate whole organismic effects include the locus coeruleal and limbic systems. Expected psychobiological consequences are examined in detail. The magnitude and temporal-spatial characteristics of weather effects indicate they are the subject matter of behavioral epidemiology.     

Course of development of isolated rat embryonic ectoderm as renal homograft

Summary When the isolated head-fold stage rat embryonic ectoderm is grafted under the kidney capsule, it gives rise to a new mesenchyme with the capacity to differentiate into mesodermal tissues.This investigation was supported by grant No. V-10/78 from the SIZ-V of S. R. Croatia.     

Course of development of isolated rat embryonic ectoderm as renal homograft.

When the isolated head-fold stage rat embryonic ectoderm is grafted under the kidney capsule, it gives rise to a new mesenchyme with the capacity to differentiate into mesodermal tissues.     

Autoradiographic studies with S35 on the development of the rat embryo

Zusammenfassung Es wurde die S³⁵-Fixation bei Embryonen von etwa 30 graviden Ratten untersucht. Bindegewebe, Knorpel und gewisse rasch wachsende Gewebe wiesen hohe Sulphataufnahmen auf, vermutlich auf Grund des Einbaues von radioaktivem Schwefel in die Sulfomukopolysachariden.