Location of sialoglycoconjugates containing the Sia(alpha)2-3Gal and Sia(alpha)2-6Gal groups in the rat hippocampus and the effect of aging on their expression.

The histochemical distribution of sialoglycoconjugates in the CA1 region in the hippocampus formation of 9-week-old rats and 30-month-old rats was examined using electron microscopy in combination with two lectins, Maackia amurensis lectin, specific for Sia(alpha)2-3Gal, and Sambucus sieboldiana agglutinin, specific for Sia(alpha)2-6Gal. Each lectin stained the plasma membranes of pyramidal cells, indicating that the Sia(alpha)2-3Gal and Sia(alpha)2-6Gal groups were expressed on their plasma membranes. These lectins also bound to synapses in the stratum lacunosum molecular. The staining intensity of the lectins in the synapses in these layers was downregulated in the 30-month-old rats. These results indicated that both the Sia(alpha)2-3Gal and Sia(alpha)2-6Gal groups are expressed on these synapses and that the expression of these sialyl linkages decreases in the aged brain     

Effect of cadmium sulphate on the metabolism of carbohydrates in organism of rats of different ages

The influence of cadmium sulfate on concentration of glucose, lactate, piruvate, alpha-ketoglutarate, malate, oxaloacetate in blood of 3-, 6- and 18-month-old poisoned rats was established the results of our researches. It was found, that poisoning of rats by cadmium sulfate causes the rise of concentration of glucose, metabolites of citric acid cycle and glycolysis in blood of animals of all age groups explored. The research results prove that in blood of 3-month-old poisoned rats the level of glycolysis and citric acid cycle activation is considerably higher in comparison with that of 6- and 18-month-old animals. As a result, a comparison of age-specific dynamics of changes of carbohydrate metabolism indices in the blood of rats, poisoned by cadmium showed that the organism of 3-month-old rats is more sensitive to toxic influence of cadmium.     

The ISIAH rat locomotion in the open field test is under control of the genes on chromosome 2 and chromosome 16

The QTL analysis was performed in order to identify the genetic loci that contribute to the behavior in the open field tests in the ISIAH rat strain with inherited stress-induced arterial hypertension. Two F2 populations of 3-4-month-old (n = 106) and 6-month-old (n = 130) male rats derived from a cross between the normotensive Wistar albino Glaxo (WAG) and hypertensive ISIAH rats were used in the search for the QTL. In 3-4-month-old rats, QTL were found: a) for the rat locomotion at the periphery of the open field in the region of D2Rat157-D2Rat88 markers (logarithm of odds (LOD) score 4.83; p= 0.000058) on Chr. 2 and in the vicinity of the D16Rat32 marker (LOD score 3.71; p = 0.00023) on Chr. 16. These two QTL describe the 42.9% of the trait variability. b) for the rat locomotion during the first minute of the open field test on Chr.16 near the D16Rat58 marker (LOD score 3.78; p = 0.00028). The results provided support for the existence of the age-dependent differences in the genetic control of the traits analyzed.     

Meningeal calcification of the rat pineal organ. Finestructural localization of calcium-ions

The surface of the pineal organ of the rat is covered by a leptomeningeal tissue, the continuation of the corresponding meningeal layers of the diencephalon. The pineal leptomeninx consists of stratified arachnoid and of pia mater cells which follow the vessels into the pineal nervous tissue. The pineal arachnoid contains electron-lucent and electron dense cells differing from each other in their cytoplasmic components. Corpora arenacea of various size and density occur among these arachnoid cells and can grow into the pineal organ alongside pia mater tissue. Acervuli often form groups in circumscribed meningeal "calcification foci". Concrements are absent or rare in the 1- and 2-month-old animal, while they are usually present in the 4- and 6-month-old rats. The electronmicroscopic localization of Ca-ions was studied in 2- and 4-month-old rats by potassium pyroantimonate cytochemistry. In the 4-month-old animals, arachnoid cells containing a varying amount of Ca-pyroantimonate deposits were found first of all around corpora arenacea, but there were also cells free of deposits in the close vicinity of the acervuli. Deposits were preferentially localized to the cytoplasm of electron dense arachnoid cells and to the cell membrane of electron-lucent cells. Most of the precipitates occurred in locally enlarged intercellular spaces. Here, microacervuli were found in 4-month-old animals suggesting that a calcium-rich environment was responsible for the appearance of the concrements. Intermediate stages between the small acervuli and large concentric corpora arenacea may indicate an appositional growth of the acervuli in the calcification foci.(ABSTRACT TRUNCATED AT 250 WORDS)     

Increases in the basal secretion rate of follicle-stimulating hormone (FSH) accompany age-associated changes in serum FSH levels on estrus

This laboratory has recently reported that by 5-6 months of age, alterations in the secretion and production of follicle-stimulating hormone (FSH) occur in virgin female rats which precedes the age-related disruption of estrous cycles and attenuation of preovulatory gonadotropin surges. Specifically, circulating immunoreactive FSH levels are higher on estrus in rats 5 months and older compared to levels measured in 2- to 3-month-old rats. Therefore, the present study was conducted to explore a possible mechanism for this age-related increase in FSH levels. At 1400 hr on proestrus, estrus and diestrus-1, groups (n = 6-12 rats/group) of 3- and 7-month-old, cyclic rats were decapitated, trunk blood was collected, and anterior pituitary glands were bisected and placed in incubation flasks containing 1 ml media (medium 199). Following a 30-min preincubation period, hemipituitary fragments were incubated for an additional 2 hr. Media and serum FSH levels were quantified by RIA. Levels of FSH were twofold higher in the serum of 7-month-old rats than 3-month-old rats on estrus. Similarly, the basal secretion rate (BSR) of FSH (expressed as ng FSH/ml/2 hr) was significantly (P less than 0.05) higher from incubated hemipituitary fragments of 7-month-old estrous rats than from fragments obtained from younger estrous rats (7 month: 1637 ng/ml/2 hr vs 3 months: 1253 ng/ml/2 hr). Neither the serum FSH levels nor the BSR of FSH differed between age groups on proestrus or diestrus-1. These results show that age-associated increases in circulating FSH levels on estrus may be attributed to an enhanced basal secretion of FSH from the pituitary gland.     

Action of ACTH in the luteal ovary.

Oestrous rats and golden hamsters were anesthetized with pentobarbital, one of the femoral arteries and veins and one of the ovarian veins were cannulated. Blood fractions were collected from the ovary. After the first two fractions synthetic adrenocorticotropic hormone (ACTH) or human chorionic gonadotropin (hCG) was injected i.v. Blood pressures and ovarian blood flow were continuously recorded. Progesterone (P) and oestradiol-17 beta (E2) were determined from the ovarian venous blood by radioimmunoassay (RIA). ACTH induced a temporary elevation in the ovarian blood flow, P and E2 secretion both in rats and hamsters. In rats and hamsters hCG induced a continuous elevation in P secretion but the ovarian blood flow and E2 secretion remained unchanged. Luteal cells from pseudopregnant rats or oestrous hamsters were dispersed with collagenase and incubated with ACTH or hCG. A sample of the cells was preincubated with polymixin-B, indomethacin or ibuprofen. P and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) contents of the medium and cyclic 3,5 adenosine monophosphate (cAMP) content of the cells were determined by RIA. ACTH stimulated the release of 6-keto-PGF1 alpha and the secretion of P from the luteal cells of both species, which was inhibited by indomethacin or ibuprofen, but ACTH did not alter the cAMP content of luteal cells. The polymixin-B prevented ACTH to stimulate P secretion, but it did not elevate the 6-keto-PGF1 alpha release, while the cAMP content of the cells remained unchanged. It is supposed that the polyphosphoinositol-Ca(2+)-protein kinase-C second messenger system is involved in the ACTH induced stimulation of P secretion.     

Life-long Dietary Restriction Modulates the Expression of Collagens and Collagen-binding Heat Shock Protein 47 in Aged Fischer 344 Rat Kidney

It has been shown that the expression of HSP47 and collagens is substantially increased in the sclerotic/fibrotic process in various organs, including kidney. However, the factors regulating the increased expression of HSP47 are not yet clear. In this study, we examined the effect of dietary restriction for the expression of collagens and collagen-binding HSP47 in the kidneys of 6- and 24-month-old male Fischer 344 (F 344) rats fed ad libitum or 30% diet-restricted. No significant histological alteration was found in the kidneys of 6-month-old fed or diet-restricted rats. Kidneys obtained from 24-month-old freely fed rats showed glomerulosclerosis with marked tubulointerstitial damage including interstitial fibrosis, while in the kidneys of 24-month-old diet-restricted rats, renal damage was remarkably less than those noted in 24-month-old freely fed rat kidneys. Immunohistochemical analysis showed an increased accumulation of type I, type III and type IV collagens in areas of glomerulosclerosis and interstitial fibrosis in old rat kidneys. Dietary restriction significantly reduces renal accumulation of collagens in old age. Aging enhanced expression of HSP47 in 24-month-old freely fed rat kidneys whereas dietary restriction suppressed its expression in 24-month-old diet-restricted rat kidneys. Also, phenotypic alterations of mesangial cells and interstitial cells (immunopositive for -smooth muscle actin), glomerular epithelial cells (immunopositive for desmin) and tubular epithelial cells (immunopositive for vimentin) were seen in 24-month-old freely fed rat kidneys and found to express HSP47. Dietary restriction significantly diminished phenotypically altered renal cells in 24-month-old rat kidneys. Our results suggest that increased expression of HSP47 is associated with age-related renal damage and that diet-restricted alteration of its expression is associated with the modulation of age-associated renal sclerosis/fibrosis.     

Effects of dexamethasone on insulin receptor in aging

The aim of this study was to examine the effects of dexamethasone (Dex) on functional properties of the rat insulin receptor (IR). Male Mill Hill hooded rats, 3, 6, 12, 18 and 21 months old, were injected with Dex (4 mg/kg) and rat liver and erythrocytes were used for experiments 18 h after Dex administration. Treatment with Dex lowered the specific binding (SB) of insulin (INS) in the liver of 3- and 18-month-old rats and concentration of INS binding sites (N1, N2) and the dissociation constant of low-affinity binding sites (Kd2) in the liver of 6- and 18-month-old rats. In addition, Dex treatment lowered the liver IR protein level in all analyzed groups, except 21-month-old rats where it remained unchanged, but raised the IR mRNA level in 18-month-old rats. In erythrocytes, treatment with Dex decreased SB and Kd2 (in animals 3 and 6 months old) and N1 (in ones 3 and 18 months old). Following Dex treatment, the INS plasma level increased (in rats 3, 18 and 21 months old), while glucose (Glu) concentration increased in 3 and 12 months old, but decreased in 6- and 21-month-old rats. In summary, Dex exerts the strongest effect on the erythrocyte IR of 3- and 6-month-old rats and the hepatic IR of 18-month-old rats. IR in both tissues is almost insensitive to Dex in 12- and 21-month-old rats. The pattern of age-related changes of IR induced by Dex does not correlate with changes of plasma Glu and INS.     

Increased Cyclooxygenase-2-Derived Prostanoids Contributes to the Hyperreactivity to Noradrenaline in Mesenteric Resistance Arteries from Offspring of Diabetic Rats

This study analyzed the effect of in utero exposure to maternal diabetes on contraction to noradrenaline in mesenteric resistance arteries (MRA) from adult offspring, focusing on the role of cyclooxygenase (COX)-derived prostanoids. Diabetes in the maternal rat was induced by a single injection of streptozotocin (50 mg/kg body weight) on day 7 of pregnancy. Contraction to noradrenaline was analyzed in isolated MRA from offspring of diabetic (O-DR) and non-diabetic (O-CR) rats at 3, 6 and 12 months of age. Release of thromboxane A₂ (TxA₂) and prostaglandins E₂ (PGE₂) and F_2α (PGF_2α), was measured by specific enzyme immunoassay kits. O-DR developed hypertension from 6 months of age compared with O-CR. Arteries from O-DR were hyperactive to noradrenaline only at 6 and 12 months of age. Endothelial removal abolished this hyperreactivity to noradrenaline between O-CR and O-DR. Preincubation with either the COX-1/2 (indomethacin) or COX-2 inhibitor (NS-398) decreased noradrenaline contraction only in 6- and 12-month-old O-DR, while it remained unmodified by COX-1 inhibitor SC-560. In vessels from 6-month-old O-DR, a similar reduction in the contraction to noradrenaline produced by NS-398 was observed when TP and EP receptors were blocked (SQ29548+AH6809). In 12-month-old O-DR, this effect was only achieved when TP, EP and FP were blocked (SQ29548+AH6809+AL8810). Noradrenaline-stimulated TxB₂ and PGE₂ release was higher in 6- and 12-month-old O-DR, whereas PGF_2α was increased only in 12-month-old O-DR. Our results demonstrated that in utero exposure to maternal hyperglycaemia in rats increases the participation of COX-2-derived prostanoids on contraction to noradrenaline, which might help to explain the greater response to this agonist in MRA from 6- and 12-month-old offspring. As increased contractile response in resistance vessels may contribute to hypertension, our results suggest a role for these COX-2-derived prostanoids in elevating vascular resistance and blood pressure in offspring of diabetic rats.     

Gender differences in the attenuation of salt-induced hypertension by angiotensin (1-7)

Chronic infusion of angiotensin (1-7) [Ang-(1-7)] lowers blood pressure in spontaneously hypertensive rats (SHR). To assess the role of Ang-(1-7) in salt-induced hypertension, Ang-(1-7) (24 microg/kg/hr) or saline was administered chronically via osmotic minipump into the jugular vein of 5-6 wk-old male (M) and female (F) Dahl salt-sensitive rats placed on a high-salt (8% NaCl) diet for 2 weeks. Blood pressure (BP) and heart rate were measured prior to the start of the diet and weekly thereafter. Ang-(1-7) significantly attenuated the BP increase after 1 wk on the diet in both M and F rats, but after 2 weeks only in F rats. Enhanced release of prostacyclin, (6-keto PGF1 alpha), following Ang-(1-7) treatment was observed in both M and F rats. In addition, significant increases in aortic blood flow and plasma levels of nitric oxide were observed in the F rats following Ang-(1-7) treatment. These findings demonstrate that the reduction in BP is due to both prostacyclin and NO and that there is a gender difference in the attenuation of salt-induced hypertension by Ang-(1-7).     

Host age and the growth and fecundity of Hymenolepis diminuta in the rat

Five, 20, and 80 cysticercoid infections of Hymenolepis diminuta were established in 1-, 2- and 5-month-old male Wistar rats. Worm numbers, dry weights and egg outputs were determined on day 28 post infection. Worm recovery was found to be independent of cysticercoid dose in 1-month-old rats, but density-dependent in older rats. Density dependence affected both worm dry weight and egg production in all 3 age classes of host studied. However, at the highest dose both dry weight and egg production were significantly decreased in 2- and 5-month-old rats compared with 1-month-old rats. The results cannot be explained solely in terms of competition for a resource, and suggest that immunological mechanisms may have an important role in the "crowding effect".     

Testosterone-induced development of the rat levator ani muscle

The perinatal development of the levator ani (LA) muscle in male and female rats was investigated by measuring the total number of muscle units (MU) (i.e., mononucleate cells, clustered or independent myotubes, and muscle fibers) in transverse semithin sections of the entire muscle and the MU cross-sectional area in 22-day-old fetuses (F22), 1-day-old (D1 = day of birth), 3-day-old (D3), and 6-day-old (D6) newborns. Male muscle contained 350 +/- 64 MU on F22, twice that of the female. The number of MU increased markedly in males from F22, but changed little in females; the number of MU in males was 760% that of females on D6. The MU cross-sectional area was greater in males on F22 (120.8 micron(s)2 +/- 7.5) and D1 (155.2 micron(s)2 +/- 64.8) than in females (F22: 89.2 micron(s) +/- 14.2, D1: 64.1 micron(s)2 +/- 19.7) and dropped to about 30 X micron(s)2 in both sexes on D6. Female rats given a single injection of testosterone propionate (TP) before D7 showed a significant increase in the number of fibers, but no increase in cross-sectional area. TP given after D7 had no effect on the fiber number, but increased the average cross-sectional area. The increase in fiber number induced by postnatal TP treatment was a permanent effect, still quantifiable in 15-month-old females. We conclude that the sexual dimorphism of the rat LA muscle is principally due to a dramatic increase in the MU number in male muscles during the perinatal period, rather than to involution of the fibers in female muscles as it is widely accepted. This increase seems to be, at least partly, under the control of testosterone.     

Development of the vasculature of the pars distalis in a tumor-susceptible strain of rat (Fischer 344) differs from vascular development in a non-tumor-susceptible strain (Lewis)

The development of the vasculature of the pars distalis of two strains of rat, Fischer 344 (F344) and Lewis (LEW), was followed in 16-day (16d) and 20-day (20d) fetuses, and in 1-day (1d), 5d, 20d, 50d, and 6-month-old females. No differences in the two strains were apparent in 16d fetuses; and the capillaries that were present were immature, i.e., tall, non-fenestrated endothelial cells, and were surrounded by poorly delineated pericapillary spaces. Immature capillaries also were predominant in 20d fetuses of both strains. Agranular folliculo-stellate cells were identifiable, projecting endfeet to the parenchymal basal lamina in 20d F344 fetuses, but not in LEW fetuses. Postnatally, the capillaries of LEW rats became progressively more thin-walled and fenestrated, and were surrounded by a pericapillary space that was well delimited by basal laminae at 20d. In 50d and 6-month LEW rats, capillaries were intact and surrounded by well-defined pericapillary spaces. By comparison in F344 rats, the capillaries remained more immature even in 50d rats and older. In addition, in F344 rats focal disruptions in endothelial cells and disruptions in parenchymal and capillary basal laminae were present in all postnatal stages, and a dramatic accumulation of plasma was evident within the pericapillary spaces at 20d. Endfeet processes of folliculo-stellate cells were abundant at the parenchymal basal lamina of 1d and 5d F344 neonates, but only rarely were identified in LEW neonates. Some activation of folliculo-stellate cells, i.e., increased numbers of lysosomes and dilated endoplasmic reticulum, was present in 50d F344 rats. Connective-tissue cells within the pericapillary space also were numerous and activated in F344 rats. Discrete gaps in the parenchymal basal lamina were evident subjacent to the folliculo-stellate cell endfeet in F344 rats but not in LEW rats. The vascular bed of F344 rats differs in its development from that of LEW rats. Characteristic of the F344 strain is a persistence of more immature capillaries, an inherent vascular fragility, and an activated state of folliculo-stellate cells.     

Age-related changes of antioxidant enzyme activities, glutathione status and lipid peroxidation in rat erythrocytes after heat stress

The aim of this study was to determine whether exposure to heat stress would lead to oxidative stress and whether this effect varied with different exposure periods. We kept 1-, 6- and 12-month-old male Wistar rats at an ambient temperature of either 22 degrees C or 40 degrees C for 3 and 7 days and measured glucose-6-phosphate dehydrogenase (G-6-PD), Cu,Zn-superoxide dismutase (Cu,Zn-SOD), catalase (CAT), selenium-dependent glutathione peroxidase (Se-GSH-Px) and glutathione-S-transferase (GST) activities and levels of thiobarbituric acid-reactive substances (TBARS), reduced glutathione (GSH) and oxidized glutathione (GSSG) in erythrocytes and determined GSH/GSSG ratio, total glutathione and the redox index. G-6-PD and CAT activities were found to be significantly increased in 1- and 6-month-old rats after 3 and 7 days of heat stress, but G-6-PD activities decreased in 12-month-old rats. Cu, Zn-SOD activity decreased in 1-month-old rats after heat stress, whereas it increased in 6- and 12-month-old rats. GST activity increased in all groups. GSH and total GSH levels and GSH/GSSG ratios decreased in 1- and 6-month-old rats but they increased in 12-month-old rats after heat stress. GSSG levels increased in 1- and 6-month-old rats but decreased in 12-month-old rats after heat stress. TBARS levels increased in all groups. Seven days of stress is more effective in altering enzyme activities and levels of GSH, GSSG and TBARS. When the effects of both heat stress and aging were examined together, it was interesting to note that they mostly influenced G-6-PD activity.     

Morphofunctional characteristics of the thyroid gland in intact and partially sympathectomized rats of different age groups

The morphological and functional age-dependent changes have been studied in the thyroid gland of infantile (1-month-old), immature (2- and 3-month-old) and sexually mature (6-month-old) male rats. The decrease in thyroid functional activity with ageing was proved. Chemical sympathectomy (guanethidine at a dose of 15 mg/kg intramuscularly for 14 days after birth) was accompanied not only by morphological reconstruction of the thyroid tissue, but also (especially in 1-month-old rats) by a delay in transport-organic phase of iodine metabolism and a decline in thyroid hormone serum level. Later on, the compensatory hormonogenesis reinforcement occurs as a result of partial adrenergic innervation recovery.     

Manifestation of the neurotoxic effect of the organochlorine pesticide hexachlorobutadiene in the postnatal period of ontogeny in the rat

Daily peroral administration of chlororganic pesticide hexachlorobutadiene in doses 8.1 mg/kg (1/20 LD50) to pregnant rats results in certain ultrastructural changes of neurocytes and myelin fibers of the spinal cord both in the animals and their offspring (newborns and 1-2-month-old rats). By means of electron paramagnetic resonance (EPR) method, changes in intensity of the EPR-signals of free radicals in the spinal cord, ceruloplasmin of blood serum have been revealed in the experimental pregnant animals, as well as in 1-month-old rats (in the latter--in the brain, too). Gas-liquid chromatography reveals the preparation contents in the adrenals, heart, brain and spinal cord, in the uterus of the pregnant animals, as well as in corresponding organs of their offspring. Certain retardation in growth and decrease in body mass are noted in the offspring.     

Preparation of (125I)-dCTP and its use as a substrate for RNA- and DNA-directed DNA synthesis.

Viable isolated parenchymal cells were incubated in a modified Waymouth medium under an oxygen tension of 30×10³ Pa at pH 7.8. Under these conditions, hepatocytes from 3-month-old rats synthesized 5.8 μg albumin/h/10⁶ cells. This value nearly equals the synthesizing capacity of intact liver tissue and is the highest activity reported so far for isolated hepatocytes. Parenchymal cells isolated from 36-month-old rats synthesized more albumin as compared to cells from 3-month-old rats. The albumin synthesizing capacity of cells isolated from 12-month-old rats was less than that of cells from 3-month-old rats.     

Anesthetic and pathological changes following high doses of ketamine and xylazine in Sprague Dawley rats

The main objective of this study was to compare the effects of ketamine and xylazine in aging rats when coadministered intraperitoneally at high anesthetic doses. Three groups (n=6 rats/group) consisting of rats at 3, 6 and 12 months of age were used. During anesthesia, animals were monitored for heart rate, respiratory frequency, blood oxygen saturation, and rectal temperature. The corneal and paw withdrawal reflex were also examined during anesthesia. During anesthesia, withdrawal and corneal reflexes were absent for progressively longer durations with increasing age. Significant decreases in cardiac and respiratory frequency and, blood oxygen saturation occurred for the 6- and 12-month-old animals. Respiratory frequency and blood oxygen saturation returned to normal at the end of the anesthesia; however, the significant decrease in cardiac frequency persisted in the 6- and 12-month-old animals. Rectal temperature was decreased significantly only in the 3-month-old animals. Pulmonary edema and effusion occurred in 50% of the 12-month-old animals. In conclusion, if ketamine-xylazine are used for anesthesia, the doses should be optimized for the age of the subjects prior to initiation of the research project.     

Meningeal calcification of the rat pineal organ

Summary The surface of the pineal organ of the rat is covered by a leptomeningeal tissue, the continuation of the corresponding meningeal layers of the diencephalon. The pineal leptomeninx consists of stratified arachnoid and of pia mater cells which follow the vessels into the pineal nervous tissue. The pineal arachnoid contains electron-lucent and electron dense cells differing from each other in their cytoplasmic components. Corpora arenacea of various size and density occur among these arachnoid cells and can grow into the pineal organ alongside pia mater tissue. Acervuli often form groups in circumscribed meningeal calcification foci. Concrements are absent or rare in the 1- and 2-month-old animal, while they are usually present in the 4- and 6-month-old rats.The electronmicroscopic localization of Ca-ions was studied in 2- and 4-month-old rats by potassium pyroantimonate cytochemistry. In the 4-month-old animals, arachnoid cells containing a varying amount of Ca-pyroantimonate deposits were found first of all around corpora arenacea, but there were also cells free of deposits in the close vicinity of the acervuli. Deposits were preferentially localized to the cytoplasm of electron dense arachnoid cells and to the cell membrane of electron-lucent cells. Most of the precipitates occurred in locally enlarged intercellular spaces. Here, microacervuli were found in 4-month-old animals suggesting that a calcium-rich environment was responsible for the appearance of the concrements. Intermediate stages between the small acervuli and large concentric corpora arenacea may indicate an appositional growth of the acervuli in the calcification foci. Occasionally, acervuli were also located inside meningeal cells.There was no sign of the formation of acervuli in the pinealocytes or elsewhere in the pineal nervous tissue proper, in the age interval (1- to 6-month-old animals) studied. These findings confirm the view that corpora arenacea can be produced in the rat by the pineal leptomeninx. The laboratory rat seems to be usefull in studying pineal calcification of the meningeal type.Supported by the Hungarian OTKA grant Nr. 1619 to B.V.     

Evaluation of a technic for the isolation of mammotropic cells using dopamine as a ligand

Pituitary cell suspension from female Wistar rats were allowed to enter the 6MB sepharose gel with added dopamine, which acts ligand attaching the mammotrophs to the gel grains. After eluting the column with 3 different dopamine buffer concentration, 3 different cellular fractions were obtained. Fraction F1 contains 5% of mammotroph cells, fraction F2 2-4% and fraction F3 90%, as determined by immunocytochemistry. The absolute amount of mammotroph cells contained in F3 fraction increases by gradually warming up the column from room temperature to 37 degrees C. The eluted F3 fraction mammotroph cells from female lactating rats is observed to be twice the amount eluted in experiments performed with virgin rats. No ultrastructural differences between fraction F1 and fraction F3 mammotroph cells have been found.