study on the postnatal development and aging changes of the neurosecretory nuclei of the hypothalamus [supraoptic and paraventricular nuclei] in the albino rat

The hypothalamus is a distinct neurological entity concerned with a variety of regulatory processes. Recently, the prescence of variations in the level of neurosecretions wth the progress of age was reported. To study the changes in the structure of magnocellular neurons in the paraventricular and supraoptic nuclei during the period of postnatal development. Furthermore, to study the changes which occurred in the structure of these neurons in the old age had been studied. A total of 52 albino rats were used. The age groups of the animals include: one day, 10 days, 20 days, 2 months and 2 years old animals. Brains were processed to be studied with Einarson's gallocyanin-chrome alum stain, Golgi- Cox method and transmission electron microscope. In addition, the number of cells in the magnocellular part of the paraventricular and supraoptic nuclei were measured in all studied age groups and statistically analyzed. In the newly born rats, the paraventricular and supraoptic nuclei were composed of small rounded condensed cells. At the age of 10 days old rats, the paraventricular nucleus appeared to be well differentiated into ventromedial [parvocellular] and dorsolateral [magnocellular] parts. With the progress of age from 10 days up to the adult stage, the cells of the supraoptic nucleus and the magnocellular part of the paraventricular nucleus appeared to be densely stained which indicated increase in the Nissl granules. Ultrastructural study showed that the cells had abundant amount of free ribosomes, rough endoplasmic reticulum and mitochondria. The nucleus had fine dispersed chromatin. Golgi-Cox study showed marked increase in extension and branching of dendrites with the progress of age during the developmental period. Morphometric study showed significant increase in the number of cells from the new born up to the adult stage. In old aged rats, the cells of the paraventricular nucleus and the supraoptic nucleus appeared to be faintly stained. Some cells had vacuolated cytoplasm. Ultrastructural study showed marked decrease in the free ribosomes and the presence of many lipofuscin pigment in the cytoplasm of cells. The nucleus showed chromatin condensation and irregularity of the nuclear membrane. In addition, there was apparent decrease in the amount of the synaptic vesicles in the presynaptic terminals making contacts with the magnocellular neurons. Golgi-Cox study revealed marked decrease in the extension and branching of dentrites. Morphometric analysis showed significant decrease in the number of cells. This study demonstrated in the presence of structural changes in the magnocellular part of the paraventricular nucleus and supraoptic nucleus during the period of development. In old age, the presence of many degenerative changes was observed. This cytoarchitectonic analysis and morphological study could help in the explanation of the functional differences in the various ages

Histological and immunohistochemical changes in placental chorionic villi of patients with poorly controlled gestational diabetes

Normal placental development is essential for normal fetal development. The placenta is a complex fetal organ that plays pleiotropic roles during fetal growth. It separates the maternal and the fetal circulation. The placenta is exposed to the regulatory influence of the hormones, cytokines, growth factors, and substrates present in the circulation, and thus may be affected by changes in any of these. Gestational diabetes is one of the most prevalent medical complications of pregnancy and may cause increased fetal wastage. To study the structural changes in the placental chorionic villi of women with poorly controlled gestational diabetes in comparison with metabolically normal pregnant women. The study was carried out on placentas from 22 full-term pregnant women. All the women delivered at 38-40 weeks of gestation. Ten placentas were from normal uncomplicated pregnancies [control group] and the other 12 were from gestational diabetic pregnancies [diabetic group]. The placentas were processed and examined using light and electron microscopy. An immunohistochemical study using S100 protein antibody was carried out. In comparison with the control group, the placentas of poorly controlled gestational diabetic mothers showed an increase in syncytial knots, partial shedding of trophoblastic microvilli, and thickening of the basement membrane of the trophoblast. Fibrinoid necrosis, villous fibrosis, and dilated congested fetal blood vessels were also observed. The frequent appearance of Hofbauer cells [placental macrophages] was observed in the diabetic placenta in comparison with the control placenta. Positive diabetic trophoblastic and stromal cells for S100 protein antibodies were observed. It is concluded that poor control of diabetes during gestation may result in structural changes in the placentas, which may contribute toward fetal complications. Further research in this field may help in finding a solution for the evaluation of the destructive changes in diabetic placenta in the initial stages of pregnancy

Effect of experimentally induced hypothyroidism during pregnancy and lactation on the retina of juvenile and adult albino rats and the possible role of thyroid hormone supplementation

Nervous system growth and differentiation are closely correlated with the presence of thyroid hormones in initial development stages. Hypothyroidism during the fetal and postnatal life results in an irreversible mental retardation syndrome. At the cellular level, T3 is known to act on neuronal, neuroretinogenesis, and glial lineages. In this study, we aimed to study the influence of hypothyroidism on retinal development in juvenile and adult rats and the effects of thyroid hormone supplementation on both periods of development. This study was conducted using 56 male albino rats. They were divided into three groups: group 1 [control group] included 24 animals, group 2 [juvenile group] included 16 animals whose mother received carbimazole [NeoMercazol] antithyroid drug at a dose of 0.02 mg/day/pregnant female during gestation and lactation, this group was further subdivided into subgroup 2a [hypothyroid juvenile animals] and subgroup 2b [thyroid hormone-supplemented juvenile animals], and group 3 [adult group] included 16 animals, this group was also further subdivided into subgroup 3a [hypothyroid adult animals] and subgroup 3b [thyroid hormone-supplemented adult animals]. At the end of the experiment, the animals were killed. Retinal specimens from all groups were processed for light and electron microscopic studies. Biochemical analysis was carried out to measure the serum levels of triiodothyronine, T4, growth hormone, and insulin growth factor-1. In addition, estimations of lipid peroxidation, catalase activity, and antioxidant enzymes were made. Statistical analysis was carried out to measure the retinal thickness. Light and electron microscopic studies showed that thyroid hormone deprivation altered the organization of the retina in juvenile and adult rats. These changes were apparent in the form of significant reduction in the retinal layer thickness. In addition, degenerative changes in some layers were observed. The group with thyroid hormone supplementation showed recovery of both structural changes and retinal thickness, this recovery was apparent in the juvenile group. Adult animals showed minimal recovery. Biochemical analysis of the serum of hypothyroid animals showed a significant increase in lipid peroxidation products and decease in the serum levels of antioxidants, growth hormone, and insulin growth factor-1, comparable with the controls. Administration of thyroid hormone significantly restored their levels especially in the juvenile group. Gestational and lactational hypothyroidism induced marked changes in the developing retina in juvenile and adult rats. These changes were mostly normalized by thyroid hormone administration especially in the juvenile group

Effect of caffeine administration on the development of skeleton of albino rat

Caffeine, a naturally occurring central nervous system stimulant, is found in coffee and coca-based foods. Although caffeine passes readily through the placenta to the fetus, caffeine-containing products are still widely consumed during pregnancy. The present work was conducted to evaluate the effects of dietary caffeine intake during pregnancy and lactation on the skeleton of the developing rat. A total number of 20 pregnant albino rats were randomly chosen and divided into 2 groups: control group: 10 dams were given saline daily from the 10[th] day of gestation until delivery through a gastric tube, and an experimental group: 10 dams were given caffeine at a dose of 100 mg /kg/day dissolved in distilled water through a gastric tube for the same period of gestation. After normal delivery, some litters from both groups were sacrificed at postnatal day 1, and others were left for lactation and sacrificed at postnatal day 30. Samples from the lumbar region of the vertebral column, upper end of ulna and upper and lower ends of radius were taken from all groups, prepared for light microscopic examination and stained with haematoxylin and eosin and toluidine blue stains. Other samples from all groups were taken randomly and stained with alizarin red stain for gross skeletal examination. Caffeine treated groups showed delayed ossification in the developing bones including the skull, forelimb, hind limb and caudal vertebrae. Histological study of the growing ends of the long bones and vertebral bodies revealed cellular disorganization of chondrocytes especially in the hypertrophic zone, delayed ossification in between degenerating chondrocytes and less developed 2ry centers of ossification in treated animals. Also, degenerative changes were observed in the histological structure of the inter-vertebral disc in both newborn and one month old treated animals in the form of shrunken nucleus pulposus and disturbed lamellar arrangement of annulus fibrosus. These observed changes could be attributed to the direct effect of caffeine on the developing skeleton or due to some of its derivatives; theobromine or methylxanthine. The delay in the endochondral ossification may be attributed to zinc deficiency produced by the administration of caffeine

study on postnatal development and ageing changes of red nucleus in the albino rat

The red nucleus is one of the most important structures in the midbrain tegmentum. It plays an important role in the control of motor activities. The aim of the present work is to demonstrate the structure of the red nucleus and the characteristics of its constituent neurons during the various stages of postnatal development, it also includes the study of the ageing effect on the features of its cells. In this work, a total number of 40 albino rats was used. The following postnatal age groups of animals were studied; newly born, seven days, fifteen days and three months old [adult rats] in addition to the aged group of animals [two years old rats]. Animals were sacrificed and the midbrain region was dissected. In each age group, three midbrain specimens were processed to be studied by Einarson's Gallocyanin stain and another three specimens were processed to be studied by Golgicox method. The ultrastructural study for the cells of the red nucleus was done by transmission electron microscope. By using Gallocyanin stain, the red nucleus appeared as a circumscribed mass of cells. The caudal magnocellular part was composed mainly of large neurons and few medium and small sized neurons. The rostral parvocellular part consisted mainly of medium and small sized neurons. The cellular content of Nissl granules increased gradually from the newly born age up to the adult stage. In the aged group of animals, the cells of the red nucleus appeared to be lightly stained as compared to the adult animals indicating loss of Nissl granules. Golgi stain revealed that the caudal magnocellular part of the red nucleus was formed of different types of cells [multipolar, pyramidal and fusiform cells]. Their nerve processes showed gradual increase in the length and branching with the progress of age up to the adult stage. In the aged group of animals, these neurons showed a decrease in the extension of the nerve processes as compared to the adult group. The ultrastructural study of the caudal magnocellular part of the red nucleus in the adult animals revealed that the large neurons were characterized by the presence of rounded nucleus while the medium sized neurons had an invaginated nucleus. The cytoplasm of these cells was rich with ribosomes, rough endoplasmic reticulum and mitochondria. Several types of axosomatic synaptic terminals appeared to be present. In the aged animals, the ultrastructural study of these cells showed marked decrease in the amount of ribosomes and rough endoplasmic reticulum as compared to the adult animals. There was also accumulation of lipofuscin granules in their cytoplasm. It was concluded from this study that during the development of the red nucleus, its constituent neurons showed a progressive increase in their content of Nissil granules from the newly born age up to the adult stage. Their nerve processes also showed increase in the extension and branching. The wide variety of synaptic terminals with rubral neurons indicated the presence of several sources involved in the integration of descending motor information. In the aged animals, the rubral neurons showed several degenerative changes that could lead to impairment of motor activities

Effects of pre-and postnatal lead toxicity on cerebellar development in rabbit offsprings

The aim of this study was to investigate the effect of lead on the postnatal development of cerebellum in rabbit off springs. Pregnant rabbits were divided into a control group and an experimental group. The experimental group received lead acetate in a dose of 15 mg /kg B.W. by intragastric intubation. Lead administration was continued to the rabbit offspring. Exposure to lead resulted in an increase in the thickness of the external granular layer in comparison to control group. This layer disappeared at 3 months control rabbits while it was still present in exposed animals of the same age. Also the molecular layer of exposed animals was affected where it became decreased in thickness. Moreover administration of lead affected the Purkinje cells where they became decreased in size with indistinct Nissl granules, marked shortening of dendrites and focal loss of them. Lead, also, resulted in decreased thickness and density of the internal granular layer. Moreover, there were oedema, cavitations and foci of calcification. From the previous findings, it could be concluded that lead has degenerative changes on the cerebellar development