Study on the mechanism of cerium nitrate effects on germination of aged rice seed

Attempts were made to promote germination of naturally and artificially aged rice seeds by treating them with cerium nitrate. The germination rate, germination index, and vigor index of aged rice seed were significantly increased by cerium. It was because the treatments of aged rice seed with cerium nitrate enhanced respiratory rate and activities of superoxide dismutase, catalase, and peroxidase, and decreased superoxide O₂ ⁻ and malondialdehyde contents that plasma membrane permeability was reduced. It was suggested that cerium be used for the seed treatment before sowing.     

The extracellular matrix of lip wounds in fetal, neonatal and adult mice.

Wound healing in the fetus occurs rapidly, by a regenerative process and without an inflammatory response, resulting in complete restitution of normal tissue function. By contrast, in the adult, wounds heal with scar formation, which may impair function and inhibit further growth. The cellular mechanisms underlying these differing forms of wound healing are unknown but the extracellular matrix (ECM), through its effects on cell function, may play a key role. We have studied the ECM in upper lip wounds of adult, neonatal and fetal mice at days 14, 16 and 18 of gestation. The spatial and temporal distribution of collagen types I, III, IV, V and VI, fibronectin, tenascin, laminin, chondroitin and heparan sulphates were examined immunohistochemically. Results from the fetal groups were essentially similar whilst there were distinct differences between fetus, neonate and adult. Fibronectin was present at the surface of the wound in all groups at 1 h post-wounding. Tenascin was also present at the wound surface but the time at which it was first present differed between fetus (1 h), neonate (12 h) and adult (24 h). The time of first appearance paralleled the rate of wound healing which was most rapid in the fetus and slowest in the adult. Tenascin inhibits the cell adhesion effect of fibronectin and during development the appearance of tenascin correlates with the initiation of cell migration. During wound healing the appearance of tenascin preceded cell migration and the rapid closure of fetal wounds may be due to the early appearance of tenascin in the wound. Collagen types I, III, IV, V and VI were present in all three wound groups but the timing and pattern of collagen deposition differed, with restoration of the normal collagen pattern in the fetus and a scar pattern in the adult. This confirms that lack of scarring in fetal wounds is due to the organisation of collagen within the wound and not simply lack of collagen formation. The distribution of chondroitin sulphate differed between normal fetal and adult tissues and between fetal and adult wounds. Its presence in the fetal wound may alter collagen fibril formation. No inflammatory response was seen in the fetal wounds. The differences in the ECM of fetal and adult wounds suggests that it may be possible to alter the adult wound so that it heals by a fetal-like process without scar formation, loss of tissue function or restriction of growth.     

Distribution, metabolism, and fetal uptake of pentavalent arsenic in pregnant mice following oral or intraperitoneal administration

Pregnant CD-1 mice were treated with 20 (i.p.) or 40 (p.o.) mg/kg sodium arsenate on gestation day 18 (plug = day 1). Individual fetuses, pooled placentas and maternal blood, urine, liver, and kidneys were obtained from three or more litters at intervals up to 24 hours following treatment. Acid-digested samples were analyzed for total arsenic by hydride generation atomic absorption spectrophotometry. The rate of arsenic elimination from maternal samples was not influenced by administration route. First-order elimination followed a brief period of distribution, and the biological half-life was approximately 10 hours. Arsenic was found in most samples, with mean peak concentrations expressed as micrograms As/gm (wet wt.) or /ml (values listed are post-treatment sampling times in minutes or hours and concentrations for i.p. and for p.o. treated groups, respectively) as follows: fetuses-2, 3.5; 6, 0.8, placentas-2, 9.3; 1, 2.3, blood-10 minutes, 6.9; 1, 2.0, urine-1, 712; 2, 342, kidney-20 minutes, 25.4; 1, 11.0, liver-0.5, 7.9; 1, 11.7. By 24 hours, arsenic levels in fetuses and placentas had declined to 0.22 microgram/gm and 0.74 microgram/gm for i.p. and 0.33 microgram/gm and 0.57 microgram/gm for p.o. treatments, respectively. Fetal arsenic uptake and loss were more rapid following i.p. than p.o. treatments, and although the i.p. dose was only half that used p.o., peak fetal As+5 was almost fivefold higher following i.p. treatment. These results agree with the finding that oral dosing of pregnant mice with arsenate has less effect on the conceptus than does treatment by injection.(ABSTRACT TRUNCATED AT 250 WORDS)     

Differential effects of sublethal irradiation on the humoral immune responses of adult and neonatal mice.

Adult and 13 day old neonatal mice were given 500 r total body irradiation and immediately immunized with T independent antigens. Whereas 500 r sublethal irradiation markedly depressed the adult plaque forming cell response, exposure to 500 r only marginally reduced the response of neonates. When antigen was delayed 2 days after 500 r, the response of the exposed neonates was equivalent to the unirradiated controls. In a study of the kinetics of the neonatal response, it was seen that irradiation resulted in an early depressed number of plaque forming cells; however, 6 days after challenge the irradiated neonates were fully recovered. These experiments characterize a sub-population of B lymphocytes by its ability to quickly recover from the effects of irradiation. This subpopulation is restricted to the neonatal period of life, and it may have important consequences in the regulation of the immune response.     

Kinetic characteristics and toxic effects of benzalkonium chloride following intravascular and oral administration in rats

Kinetic characteristics and toxic effects of benzalkonium chloride (BZK) following injection via jugular vein (JV), femoral artery (FA) and oral administration (PO) were experimentally investigated using rats. The BZK concentrations in blood and tissues (lung, liver and kidney) were determined by high-performance liquid chromatography with solid phase extraction. Toxic doses of 15 and 250 mg/kg of BZK were used for intravascular (JV and FA) and PO administration, respectively. The fatal effects appeared soon after the dose in JV-rats, while delayed in FA- or PO-rats. The blood BZK concentrations and the elimination half-lives were similar between JV- and FA-rats, while the distribution of BZK in tissues was slightly different. In PO administration, the rats that aspirated BZK into their lungs had some symptoms, while the rats that did not aspirate BZK appeared to be normal. The BZK concentrations in blood and tissues were significantly higher in the aspirated PO-rats. The toxic degree of BZK was correlated with the BZK concentration in orally dosed rats. Lung and kidney had higher BZK concentrations compared to blood or liver, and they could be the target organs of BZK.Keyword: Benzalkonium chloride     

The fine structure of the thymus of the fetal and neonatal monkey (Macaca mulatta)

Summary The morphologic features of the fetal and neonatal thymus were investigated by light and electron microscopy to determine developmental changes. Primitive epithelial cells differentiate into reticular epithelial cells, medullary epithelial cells, elongated epithelial cells, Hassall's corpuscles and cysts. Thymocytes first appear at 50 days fetal age and the number of thymocytes is amplified from 75–150 days fetal age. Minor differences between the fetal thymus of the monkey and that of other species were observed. Possible functions for the various cellular components of the fetal monkey thymus are discussed.This research was supported in part by grants 5-F3-CA-28, 793-02 and FR-0167 from the National Institutes of Health.     

Engrafting fetal liver cells into multiple tissues of healthy adult mice without the use of immunosuppressants

We have shown the fetal liver cell engraftments into multiple tissues of adult healthy mice, achieved without suppressing the animals’ immune systems. Fetal cells from the livers of male C57Bl/6J Black lineage mice at day 13 to 15 of gestation were injected intravenously into female adult CC57W/MY White mice. The grafting was evaluated by Y-chromosome-specific PCR, cytometric analysis of fluorescently stained donor cells, and histological analysis. All the methods consistently showed the presence of multiple engraftments randomly distributed through the various organs of the recipients. After 60 days, the grafts still constituted 0.1 to 2.75% of the tissues. The grafted cells did not change their appearance in any of the organs except the brain, where they became enlarged. Inflammatory reactions were not detected in any of the histological preparations. The frequency of engraftments was higher in the liver, indicating that similarity between the donor and recipient cells facilitates engraftment. The high inherent plasticity of fetal liver cells underlies their ability to integrate into healthy recipient organs, which can be governed by environmental conditions and connections with neighboring cells rather than by the initial cellular developmental programs. The fact that fetal liver cells can be grafted into multiple tissues of healthy animals indicates that they can be used to replace the natural loss of cells in adult organisms.     

Regulation of rabbit fetal glycogen: effect of in utero fetal decapitation on the metabolism of glycogen in fetal heart, lung, and liver

To understand the control mechanisms involved in the regulation of fetal glycogen, we have studied the effect of in utero fetal decapitations on glycogen metabolism in rabbit fetal heart, lung, and liver. In utero fetal decapitations were performed between days 18 and 21 of gestation. Two to four fetuses on one side of the horn were decapitated. Fetuses were delivered between days 23 and 26 or between days 28 and 30 of gestation. Fetal heart, lungs, and liver were analyzed for DNA, protein, glycogen, glycogen synthase (I and D forms), glycogen phosphorylase (a and b forms), phosphofructokinase, pyruvate kinase, and lactic dehydrogenase. In fetal heart and lung, no difference was observed in any of the above measurements in the intact and decapitated fetuses. In contrast, fetal liver does not appear to develop the glycogen system as indicated by the very low levels of glycogen (0.02 mg/mg DNA) in decapitated fetuses as compared with intact fetuses (0.4 mg/mg DNA). Similarly the levels of glycogen synthase and phosphorylase were two to three times lower in livers from decapitated fetuses as compared with the livers from intact fetuses. The three enzymes phosphofructokinase, pyruvate kinase, and lactic dehydrogenase were not affected by fetal decapitation in all three tissues. These results indicate that the fetal hypothalamic-pituitary-adrenal (thyroid) axis is not required at least after day 18 of gestation for the normal accumulation and subsequent utilization of glycogen in fetal heart and lungs, while it is an absolute requirement for the development of the fetal liver glycogen system.(ABSTRACT TRUNCATED AT 250 WORDS)     

Development, maturation and subsequent activation of follicular dendritic cells (FDC): immunohistochemical observation of human fetal and adult lymph nodes

To elucidate the processes involved in development and activation of human follicular dendritic cells (FDC), immunohistochemistry was performed on paraffin sections of fetal lymph nodes (FLN) obtained from archived autopsy material, and of adult reactive lymph nodes (ARLNs) excised for diagnostic purpose, using a panel of antibodies. Our study showed that tiny clusters of CNA.42⁺ KiM4p⁺ cells, surrounded by some B-lymphocytes, initially arose in the cortical area of underdeveloped FLN around the 20th gestational week. No co-expression of CD21 and CD35 was found. In the relatively developed FLN of the same gestational age, small eddies of immature FDC, which expressed CD21, CD35, and nerve growth factor receptor (NGFR), as well as CNA.42 and KiM4p, were observed within ill-defined aggregations of B-lymphocytes. As gestation progressed, more B-lymphocytes assembled in a compact manner and formed primary lymphoid follicles containing an extending web of mature FDC, which expressed CNA.42, KiM4p, CD21, CD35, NGFR, and sometimes CD23 and X-11. In well-developed secondary follicles of ARLNs, activated FDC expressed additional molecules such as CD55, CD106, and S100α. Our observations identified the processes of phenotypic alteration of human FDC and established practical indicators determining their developmental stage and functional phase.     

Immunolocalization of steroidogenic enzymes in the fetal, neonatal and adult testis of the shiba goat.

The localizations of steroidogenic enzymes (P450scc, 3betaHSD, P450c17 and P450arom) in testes of Shiba goats were investigated by immunohistochemistry. P450scc, 3betaHSD, P450c17 and P450arom were detected in all Leydig cells of adults. P450scc and P450c17 were observed in most Leydig cells in the fetus (90 days) and neonate (15 days). 3betaHSD and P450arom were found in some Leydig cells of the fetus with weak immunostaining but the numbers of immunopositive Leydig cells and intense immunostaining were increased in Leydig cells of the neonate. These results suggest that Shiba goat testes have the ability to synthesize progestin, androgen and estrogen in the fetus, neonate and adult, and synthesis of these steroid hormones showed an age-related rise.     

Respiratory and cardiovascular effects of doxapram and theophylline for the treatment of asphyxia in neonatal calves

Respiratory stimulants are widely used in asphyxic neonatal calves despite a lack of data about their effectiveness and indications of possible side effects. The effect of doxapram and theophylline on respiratory, cardiovascular, and acid-base variables was investigated in 10 healthy neonatal calves (Bos Taurus). A venous, a peripheral arterial, and a pulmonary arterial catheter were placed, and central venous, pulmonary, and systemic blood pressures and cardiac output were measured using thermodilution technique. Doxapram, but not theophylline, led to an immediate increase in respiratory rate (P ≤ 0.01). The arterial pCO₂ decreased to 27.1 ± 4.7 mm Hg within 30 sec after doxapram administration and to 46.3 ± 5.8 mm Hg within 120 min after theophylline administration (P < 0.0001). The systolic pulmonary pressure increased from 70 ± 8 mm Hg (mean ± SD) to 93 ± 19 mm Hg within 30 sec after doxapram, but decreased after theophylline. The pulmonary vascular resistance also increased after doxapram and decreased after theophylline (P < 0.01). Doxapram had a more pronounced and faster effect on respiratory rate and elimination of CO₂ than theophylline. Doxapram, but not theophylline, is indicated for treatment of postnatal asphyxia in calves, but there are potential cardiovascular side effects.     

Acute effects of drug administration and withdrawal on the benzodiazepine receptor

Effects of one week of benzodiazepine drug administration on central benzodiazepine receptor binding characteristics were evaluated in a series of experiments in male Sprague-Dawley rats. Administration of short- and intermediate-acting benzodiazepines was observed to increase the number of available receptor binding sites (B_max) without changing affinity of drug for receptor. Furthermore, these changes did not occur after administration and withdrawal of long-acting benzodiazepines. In addition, there appeared to be a relationship between the affinity of the different benzodiazepines for the receptor and the degree of increase in the number of receptor binding sites. The results may help to explain the relationship between withdrawal of certain benzodiazepine drugs and the occurrence of rebound phenomena in clinical situations.     

Persistent effects of prenatal, neonatal, or adult treatment with flutamide on the hypothalamic-pituitary-adrenal stress response of adult male rats

To explore the role of androgens in early development on adult hypothalamic-pituitary-adrenal (HPA) function in males, we administered flutamide or vehicle injections: (1) to pregnant dams on embryonic days 15-20; (2) to neonatal pups on days 0-5; or (3) to adults on days 55-60. At approximately 70 days of age, trunk blood was collected to determine corticosterone levels (1) upon removal from the home cage, (2) immediately after 30 min of restraint stress, or (3) 60 min after return to home cage following the stressor. Flutamide treatment resulted in higher basal levels of testosterone and stress levels of corticosterone compared to vehicle treatment, and there was no interaction of treatment with age at time of treatment. This suggests that testosterone is less effective at inhibiting HPA function in flutamide-treated males. In addition, prenatally treated males had higher stress levels of corticosterone than neonatally and adult-treated males, regardless of the type of treatment. There were no differences in CBG levels among the groups. The results suggest that, in males, flutamide treatment has a long-lasting effect on HPA function. These results are consistent with our previous research on neonatally gonadectomized males and the hypothesis of organizational effects of sex hormones on HPA function.     

口服活性AdipoRon对2型糖尿病小鼠肝脏氧化应激的干预作用

目的：研究口服活性AdipoRon对2型糖尿病小鼠肝脏氧化应激是否有干预作用,为临床应用提供基础资料。方法：将健康雄性C57BL/6小鼠分为正常组（n=8）,糖尿病组（n=8）,AdipoRon高剂量治疗组（n=8）,Adi-poRon低剂量治疗组（n=8）,以高脂饲料喂养6周后腹腔注射40 mg/kg链脲佐菌素（STZ）诱导2型糖尿病模型,用高、低剂量的口服活性AdipoRon分别对治疗组灌胃治疗10 d后,检测相关生化指标,Western-blot法检测肝脏组织中IRS-1蛋白的表达;实时荧光定量PCR检测胰腺组织中PDX-1 mRNA的表达。结果：DM组小鼠血糖值明显高于NC组（P < 0.05）,DM+L组和DM+H组小鼠血糖值显著低于DM组。DM组小鼠肝脏组织中超氧化物歧化酶（SOD）、过氧化氢酶（CAT）活性显著低于NC组（P < 0.05）,丙二醛（MDA）及一氧化氮合酶（NOS）活性显著高于NC组（P <0.05）;DM+L组和DM+H组SOD、CAT活性明显高于DM组（P < 0.05）,MDA及NOS活性显著低于DM组（P <0.05）。肝脏组织中IRS-1的蛋白表达及胰腺PDX-1 mRNA表达显著升高,存在统计学意义（P < 0.05）。结论：口服活性AdipoRon对糖尿病小鼠肝脏组织氧化应激有一定的干预作用,能降低小鼠的血糖水平。     

Subacute toxic effects of silver nanoparticles oral administration and withdrawal on the structure and function of adult Albino Rats’ hepatic tissue

Products containing Silver nanoparticles (Ag NPs) are becoming vastly used in our daily life. The widespread increased introduction of Ag NPs in many aspects of life has raised researchers' concerns regarding their safety and toxicity for biological and environmental life in the past few years. The current study aimed to explore the subsequent effects of Ag NPs withdrawal, following short-term oral administration. Eighteen rats were assigned randomly into three groups (control group "1" and AG NPs treated groups "2" and "3"; 6 animals each). The control group received normal food and tap water while groups 2 & 3 received 0.5 ml of a solution containing 25 ppm Ag NPs for 14 days. Group 2 rats were sacrificed on day 14 whereas group 3 was left for another 14 days of particle cessation followed by euthanasia on day 28. Functional assessment was done by liver enzyme assays, hydrogen peroxide activity, hepatic Bdnf expression, and P53 immunoreactivity. Hepatic tissue structural assessment was done via hematoxylin and eosin, periodic acid-Schiff as well as Masson's trichrome stains. The results revealed a significant elevation of Hydrogen peroxide in group 2 only compared to the control group. Hepatic Bdnf and liver enzymes were both insignificantly affected. Structural abnormalities and enhanced apoptosis in hepatic tissue were found 14 days after ceasing the nanoparticles. In conclusion: Structural and functional insults following Ag NPs oral administration continues after particle withdrawal, and interestingly they do not necessitate apparent reflection on liver enzyme assays.     

Hormonal factors in the control of heart rate in normoxaemic and hypoxaemic fetal, neonatal and adult sheep

The relationship of plasma levels of adrenaline, noradrenaline, arginine vasopressin (AVP) and plasma renin activity (PRA) to heart rate were studied in normoxaemic and hypoxaemic fetal, neonatal and adult sheep. The mean heart rate response of fetuses at the end of a 30 minute period of 10% oxygen delivery to the maternal ewe was tachycardia. However bradycardia, usually of a transient nature, was observed in 9 of the 12 fetuses (P less than 0.05). Multiple regression analysis was used to determine the contribution of blood gas, blood pressure and plasma hormone levels to the variance in heart rate in the perinatal sheep. 22% of the variance in fetal heart rate was provided by PRA and age from conception (P less than 0.001). Tachycardia was the invariable heart rate response of the neonates and adults to hypoxaemia. 61% of the variance in neonatal heart rate was contributed by PaO2, PaCO2, AVP, PRA and systolic blood pressure (SBP, P less than 0.001). PaO2 and plasma levels of adrenaline were significantly related to adult heart rate (P less than 0.001). Those fetuses which developed bradycardia had lower PaO2 but higher AVP and PRA during hypoxaemia than those which did not develop bradycardia. The major determinant of the area of the fetal bradycardia response was found, by multiple regression analysis, to be plasma adrenaline concentration (P less than 0.05). Thus different hormonal factors may play a role in the regulation of heart rate in normoxaemic and hypoxaemic fetal, neonatal and adult sheep.