The reduction of inorganic sulphate to inorganic sulphite in the small intestine of the rat

1. Whole scrapings of rat intestinal mucosa were incubated with carrier-free sodium [³⁵S]sulphate. Radioactivity was found in S-sulphocysteine and to a small extent in S-sulphoglutathione. 2. Whole scrapings of rat intestinal mucosa incubated with carrier-free sodium [³⁵S]sulphate and oxidized glutathione formed S[³⁵S]-sulphoglutathione as the main radioactive product. The amount of S[³⁵S]-sulphocysteine formed was considerably lower than in a control that contained no oxidized glutathione. 3. The supernatant fraction of homogenates of rat intestinal mucosa catalyses the NADPH-dependent reduction of adenosine 3′-phosphate 5′-sulphatophosphate to inorganic sulphite. NADH or GSH fail to replace NADPH as reducing agents. 4. The formation of inorganic [³⁵S]sulphite from inorganic [³⁵S]-sulphate may account for the incorporation of [³⁵S]sulphate into S-sulphoglutathione by the small intestine of the rat in vivo and in vitro.     

Metabolic rate of neonate goannas (Squamata: Varanidae)

At 35°C, the standard and maximal metabolic rates for neonates of four species of goannas (Varanus brevicauda, V. eremius, V. tristis and V. gouldii) are consistently higher than predicted by intraspecific equations for adults. However, this is difficult to demonstrate statistically. The consequence of this is that the data for neonates probably should be excluded from the data used to establish intraspecific allometric regression equations for adults. From an interspecific perspective, neonate V. mertensi have a lower standard (0.16 ml O₂ g⁻¹ per h) and maximal (1.18 ml g⁻¹ per h) metabolic rate than neonate V. brevicauda (0.22 ml g⁻¹ per h), V. eremius (0.28 and 2.94 ml g⁻¹ per h, respectively), V. tristis (0.33 and 3.43 ml g⁻¹ per h) and V. gouldii (0.29 and 5.24 ml g⁻¹ per h) at 35°C. Such interspecies differences need to be accounted for in interspecific allometric analysis.     

Immunomodulatory Effects of Escherichia coli ATCC 25922 on Allergic Airway Inflammation in a Mouse Model

Background

Hygiene hypothesis demonstrates that the lack of microbial exposure would promote the development of allergic airway disease (AAD). Therefore, the gut microbiota, including Escherichia coli (E. coli), would probably offer a potential strategy for AAD.

Objective

To investigate whether E. coli infection is able to suppress the induction of AAD and to elucidate the underlying mechanisms.

Methods

Nonpathogenic E. coli ATCC 25922 was infected by gavage before AAD phase in three patterns: 10⁸ or 10⁶ CFU in neonates or 10⁸ CFU in adults. Then mice were sensitized and challenged with ovalbumin (OVA) to induce allergic inflammation in both the upper and lower airways. Hallmarks of AAD, in terms of eosinophil infiltration and goblet cell metaplasia in subepithelial mucosa, Th2 skewing of the immune response, and levels of T regulate cells (Tregs), were examined by histological analysis, ELISA, and flow cytometry, respectively.

Results

E. coli, especially neonatally infected with an optimal dose, attenuated allergic responses, including a decrease in nasal rubbing and sneezing, a reduction in eosinophil inflammation and goblet cell metaplasia in subepithelial mucosa, decreased serum levels of OVA-specific IgE, and reduced Th2 (IL-4) cytokines. In contrast, this effect came with an increase of Th1 (IFN-r and IL-2) cytokines, and an enhancement of IL-10-secreting Tregs in paratracheal lymph nodes (PTLN).

Conclusion

E. coli suppresses allergic responses in mice, probably via a shift from Th1 to Th2 and/or induction of Tregs. Moreover, this infection is age- and dose-dependent, which may open up novel possibilities for new therapeutic interventions.     

Distribution of Intravenously Administered Acetylcholinesterase Inhibitor and Acetylcholinesterase Activity in the Adrenal Gland: 11C-Donepezil PET Study in the Normal Rat

Purpose

Acetylcholinesterase (AChE) inhibitors have been used for patients with Alzheimer''s disease. However, its pharmacokinetics in non-target organs other than the brain has not been clarified yet. The purpose of this study was to evaluate the relationship between the whole-body distribution of intravenously administered ¹¹C-Donepezil (DNP) and the AChE activity in the normal rat, with special focus on the adrenal glands.

Methods

The distribution of ¹¹C-DNP was investigated by PET/CT in 6 normal male Wistar rats (8 weeks old, body weight  = 220±8.9 g). A 30-min dynamic scan was started simultaneously with an intravenous bolus injection of ¹¹C-DNP (45.0±10.7 MBq). The whole-body distribution of the ¹¹C-DNP PET was evaluated based on the Vt (total distribution volume) by Logan-plot analysis. A fluorometric assay was performed to quantify the AChE activity in homogenized tissue solutions of the major organs.

Results

The PET analysis using Vt showed that the adrenal glands had the 2nd highest level of ¹¹C-DNP in the body (following the liver) (13.33±1.08 and 19.43±1.29 ml/cm³, respectively), indicating that the distribution of ¹¹C-DNP was the highest in the adrenal glands, except for that in the excretory organs. The AChE activity was the third highest in the adrenal glands (following the small intestine and the stomach) (24.9±1.6, 83.1±3.0, and 38.5±8.1 mU/mg, respectively), indicating high activity of AChE in the adrenal glands.

Conclusions

We demonstrated the whole-body distribution of ¹¹C-DNP by PET and the AChE activity in the major organs by fluorometric assay in the normal rat. High accumulation of ¹¹C-DNP was observed in the adrenal glands, which suggested the risk of enhanced cholinergic synaptic transmission by the use of AChE inhibitors.     

Studies on the mode of action of calciferol: Subcellular localization of 1,25-dihydroxyvitamin D3 in chicken parathyroid glands

As a further means of evaluating 1,25-dihydroxyvitamin D₃-parathyroid gland interaction and its relation to calcium homeostasis, a comparative study of the subcellular localization of 1,25-dihydroxyvitamin D₃ [1,25(OH)₂D₃]in the parathyroid glands, intestinal mucosa, kidney, and liver of rachitic chickens has been carried out. Only in the chromatin fraction from parathyroids and intestinal mucosa could there be demonstrated selective and specific localization of the 1,25(OH)₂D₃. The chromatin-bound picomoles of 1,25(OH)₂D₃ (per gram of tissue) was in the ratio (mucosa:parathyroids:kidney:liver) of 1.0:0.23:0.11:0.17 2 h after an intracardial injection of 290 pmol of [³H]1,25(OH)₂D₃. This same ratio after a 30-min (23 °C) homogenate incubation with 1 × 10^?8m [³H]1,25(OH)₂D₃ was 1.0:1.0:0.10:0.03. Analogous results were obtained when reconstituted chromatin and cytosol fractions from the different tissues were compared for chromatin localization efficiency. This chromatin localization of 1,25(OH)₂D₃ in the parathyroid glands was temperature dependent. In addition, parathyroid glands were found to contain 3.0–3.5 S cytoplasmic and KCl-extractable chromatin receptors specific for 1,25(OH)₂D₃.     

Localization of histamine and histamine H2-receptor antagonists in the gastric mucosa.

Synopsis Histamine stimulates acid secretion by the parietal cell and this secretion is inhibited by the histamine H₂-receptor antagonists. Whole body autoradiography showed that radioactivity from¹⁴C-histamine was localized in the artery walls of the stomach and in the muscularis mucosae, but that the level in the fundic mucosa was the same as the blood.When the H₂-receptor antagonists burimamide, metiamide and cimetidine were labelled with³⁵S,¹⁴C or³H and dosed to rats, whole body autoradiography showed that the stomach was predominantly labelled in the glandular mucosa from 5 to 120 min after administration. Microautoradiography in the rat and dog after intravenous injection of [³H] metiamide or [³H] cimetidine demonstrated an uptake of tritium in the parietal cell cytoplasm that was 3- to 4-times greater than that found in adjacent peptic cells or areas of muscularis mucosa. The preferential labelling persisted at a low level up to 6 h after injection in the rat. The localization of radioactivity from the H₂-antagonists in the parietal cell cytoplasm correlates well with their pharmacological activity in preventing acid secretion from this cell.     

Intestinal CD103+ Dendritic Cells Are Key Players in the Innate Immune Control of Cryptosporidium parvum Infection in Neonatal Mice

Cryptosporidium parvum is a zoonotic protozoan parasite found worldwide, that develops only in the gastrointestinal epithelium and causes profuse diarrhea. Using a mouse model of C. parvum infection, we demonstrated by conditional depletion of CD11c+ cells that these cells are essential for the control of the infection both in neonates and adults. Neonates are highly susceptible to C. parvum but the infection is self-limited, whereas adults are resistant unless immunocompromised. We investigated the contribution of DC to the age-dependent susceptibility to infection. We found that neonates presented a marked deficit in intestinal CD103+ DC during the first weeks of life, before weaning, due to weak production of chemokines by neonatal intestinal epithelial cells (IEC). Increasing the number of intestinal CD103+ DC in neonates by administering FLT3-L significantly reduced susceptibility to the infection. During infections in neonates, the clearance of the parasite was preceded by a rapid recruitment of CD103+ DC mediated by CXCR3-binding chemokines produced by IEC in response to IFNγ. In addition to this key role in CD103+ DC recruitment, IFNγ is known to inhibit intracellular parasite development. We demonstrated that during neonatal infection CD103+ DC produce IL-12 and IFNγ in the lamina propria and the draining lymph nodes. Thus, CD103+DC are key players in the innate immune control of C. parvum infection in the intestinal epithelium. The relative paucity of CD103+ DC in the neonatal intestine contributes to the high susceptibility to intestinal infection.

Authors Summary

Dendritic cells are central to the defense against mucosal pathogens. They are numerous and form a uniform network in the intestinal mucosa of adults, but are poorly characterized in the intestine of neonates. Young animals are more susceptible than adults to intestinal pathogens, such as Cryptosporidium parvum, a zoonotic agent distributed worldwide that develops in the epithelium of the small intestine causing profuse diarrhea. We show that dendritic cells are scarce in the small intestine of neonates until weaning and that increasing their numbers in vivo results in increased resistance to infection. Using a conditional depletion model we demonstrate that the presence of dendritic cells is necessary for the control of the infection in both neonates and adults. During infection in neonates, dendritic cells are rapidly recruited into the intestine by chemokines produced by the epithelium and produce interferon gamma, a cytokine that inhibits parasite development in epithelial cells. Thus, the low number of dendritic cells in the intestinal mucosa of neonates is responsible for their sensitivity to cryptosporidiosis, and probably contributes to the general susceptibility of neonates to intestinal diseases.     

Salivary gland branching morphogenesis: a quantitative systems analysis of the Eda/Edar/NFκB paradigm

Background  

Ectodysplasin-A appears to be a critical component of branching morphogenesis. Mutations in mouse Eda or human EDA are associated with absent or hypoplastic sweat glands, sebaceous glands, lacrimal glands, salivary glands (SMGs), mammary glands and/or nipples, and mucous glands of the bronchial, esophageal and colonic mucosa. In this study, we utilized Eda ^Ta (Tabby) mutant mice to investigate how a marked reduction in functional Eda propagates with time through a defined genetic subcircuit and to test the proposition that canonical NFκB signaling is sufficient to account for the differential expression of developmentally regulated genes in the context of Eda polymorphism.     

Cellular and molecular mechanisms underlying the strong neonatal IL-12 response of lamb mesenteric lymph node cells to R-848

Background

Comparative studies on the response of neonates and adults to TLR stimulation have been almost exclusively limited to comparisons of human neonatal cord blood cells with peripheral blood from adults, and analyses of spleen cell responses in mice. We need to extend these studies and gain further information regarding such responses at mucosal sites.

Methodology/Principal Findings

We used sheep as a large animal model to study TLR agonist responses in the lymph nodes draining the intestine, an organ that must adapt to profound changes after birth. In response to the imidazoquinoline compound R-848, neonatal mesenteric lymph node (MLN) and spleen cells produced more IL-12 and, consequently, more IFNγ than their adult counterparts. This difference was age-related for both organs, but the preferential IL-12 response decreased more rapidly in the MLN, with young animals producing similar amounts of this cytokine to adults, from the age of 20 days onwards. Intracellular assays and depletion experiments identified CD14⁺CD11b⁺CD40⁺ cells as the main producer of IL-12. These cells accounted for a greater proportion of neonatal than of adult MLN cells, and also produced, in direct response to R-848, more IL-12 after isolation. This strong IL-12 response in neonates occurred despite the production of larger amounts of the regulatory cytokine IL-10 and the stronger upregulation of SOCS-1 and SOCS-3 mRNA levels than in adult cells, and was correlated with an increase in p38/MAPK phosphorylation.

Conclusions/Significance

This is the first attempt to decipher the mechanism by which neonatal MLN cells produce more IL-12 than adult cells in response to the TLR8 agonist R-848. CD14⁺CD11b⁺CD40⁺ IL-12-producing cells were more numerous in neonate than in adult MLN cells and displayed higher intracellular responsiveness upon R-848 stimulation. This work provides relevant information for future vaccination or immunostimulation strategies targeting neonates.     

Metabolism of the plant sulfolipid—Sulfoquinovosyldiacylglycerol: Degradation in animal tissues

Metabolism of the plant sulfolipid—sulfoquinovosyldiacylglycerol (SQDG)—was studied in animal tissues. In vivo experiments with [³⁵S]SQDG in guinea pigs showed that this lipid is not absorbed intact in the gastrointestinal tract. In these experiments, 3 h after administration of [³⁵S]SQDG, the intestinal mucosa contained 1 to 5% of the radioactivity as SQDG, while the remainder was in a water-soluble form. Analysis of the water-soluble components showed that about 60% of the radioactivity was present as sulfoquinovosylglycerol (SQG) and the remainder was present as free SO²⁻₄. In the blood, 99% of the radioactivity was present as SO²⁻₄, SQG was not observed. In liver, only very little radioactivity was observed and appeared to be mainly in the form of SO²⁻₄. Experiments with everted intestinal sacs of guinea pigs confirmed the formation of SQG, SO²⁻₄, and, in addition, sulfoquinovosylmonoacylglycerol (SQMG) in this tissue. In vitro experiments with saline extracts of acetone powders of pancreas and intestinal mucosa of guinea pig, sheep, and rat showed that [³⁵S]SQDG was deacylated to SQMG (sulfolipase A activity) and SQG (sulfolipase B activity). It is concluded that animal tissues deacylate SQDG in a stepwise manner to SQG. It is further metabolized to yield free SO²⁻₄ by cleavage of the C-S bond which appears to be brought about by the intestinal microflora. Sheep pancreatic sulfolipases were characterized. Bile salts, sodium dodecyl sulfate, and Triton X-100 inhibited the pancreatic sulfolipases, while CaCl₂ activated them. Substrate competition experiments and investigations on substrate specificity with a partially purified preparation indicated that relatively specific sulfolipase(s) may exist in pancreas. Among the species tested, guinea pig tissues showed the highest sulfolipase A and B activities followed sheep and rat tissues. Pancreatic enzymes were 18 to 60 times more active than intestinal enzymes.     

Effects of prostaglandin E1 on the metabolism in rat parathyroid gland in vitro

We investigated some effects of prostaglandin E₁ on the metabolism of rat parathyroid glands using a culture system containing basal Eagle's medium supplemented with 5–10% heat-inactivated rat serum. Rat parathyroid glands incorporate [³H]fucose and ¹⁴C-labeled amino acids into cellular glycoproteins and secrete some of these into the culture medium. Gel filtration chromatography separates these glycoproteins into three classes, the smallest of which (peak 3) is secreted with immunoreactive parathyroid hormone. In cultures of 48 h, prostaglandin E₁ (1 μg/ml) specifically inhibits the secretion of peak 3 and of parathyroid hormone but has no effect on the incorporation of [³H]-fucose, ¹⁴C-labeled amino acids, or [³H]uridine into parathyroid glands. Cytochalasin B inhibits the secretion of parathyroid hormone and the incroporation of isotopic fucose and amino acids. Cortisol stimulates incorporation of [³H]fucose and the secretion of parathyroid hormone even in the presence of inhibitory doses of prostaglandin E₁. It is concluded that, in organ culture, prostaglandin E₁ inhibits the secretion of parathyroid hormone and of a specific glycoprotein the function of which may be related to the secretion of the hormone.     

Radioprotective Effect of Lidocaine on Neurotransmitter Agonist-Induced Secretion in Irradiated Salivary Glands

Background

Previously we verified the radioprotective effect of lidocaine on the function and ultrastructure of salivary glands in rabbits. However, the underlying mechanism of lidocaine''s radioprotective effect is unknown. We hypothesized that lidocaine, as a membrane stabilization agent, has a protective effect on intracellular neuroreceptor-mediated signaling and hence can help preserve the secretory function of salivary glands during radiotherapy.

Methods and Materials

Rabbits were irradiated with or without pretreatment with lidocaine before receiving fractionated radiation to a total dose of 35 Gy. Sialoscintigraphy and saliva total protein assay were performed before radiation and 1 week after the last radiation fraction. Isolated salivary gland acini were stimulated with either carbachol or adrenaline. Ca²⁺ influx in response to the stimulation with these agonists was measured using laser scanning confocal microscopy.

Results

The uptake of activity and the excretion fraction of the parotid glands were significantly reduced after radiation, but lidocaine had a protective effect. Saliva total protein concentration was not altered after radiation. For isolated acini, Ca²⁺ influx in response to stimulation with carbachol, but not adrenaline, was impaired after irradiation; lidocaine pretreatment attenuated this effect.

Conclusions

Lidocaine has a radioprotective effect on the capacity of muscarinic agonist-induced water secretion in irradiated salivary glands.     

First Outbreak with MRSA in a Danish Neonatal Intensive Care Unit: Risk Factors and Control Procedures

Introduction

The purpose of the study was to describe demographic and clinical characteristics and outbreak handling of a large methicillin-resistant Staphylococcus aureus (MRSA) outbreak in a neonatal intensive care unit (NICU) in Denmark June 25^th–August 8^th 2008, and to identify risk factors for MRSA transmission.

Methods

Data were collected retrospectively from medical records and the Danish Neobase database. All MRSA isolates obtained from neonates, relatives and NICU health care workers (HCW) as well as environmental cultures were typed.

Results

During the 46 day outbreak period, 102 neonates were admitted to the two neonatal wards. Ninety-nine neonates were subsequently sampled, and 32 neonates (32%) from 25 families were colonized with MRSA (spa-type t127, SCCmec V, PVL negative). Thirteen family members from 11 of those families (44%) and two of 161 HCWs (1%) were colonized with the same MRSA. No one was infected. Five environmental cultures were MRSA positive. In a multiple logistic regression analysis, nasal Continuous Positive Airway Pressure (nCPAP) treatment (p = 0.006) and Caesarean section (p = 0.016) were independent risk factors for MRSA acquisition, whereas days of exposure to MRSA was a risk factors in the unadjusted analysis (p = 0.04).

Conclusions

MRSA transmission occurs with high frequency in the NICU during hospitalization with unidentified MRSA neonates. Caesarean section and nCPAP treatment were identified as risk factors for MRSA colonization. The MRSA outbreak was controlled through infection control procedures.     

Immunomodulation of tahneeq method in IL-12 and CD8+ T-Lymphocyte,an in-vivo study in neonatal rats

Stimulation of the neonatal immune system is quite important for the proliferation and differentiation of antigen-presenting cells (APCs) and T cells. Tahneeq is a traditional method to manually rub the palatal mucosa of newborn babies with premasticated Ajwa palm dates. The present study was to investigate the tahneeq effects on IL-12 expression of dendritic cells (DCs) and blood T lymphocytes expressing CD8⁺ in neonatal Wistar rats. The number of 90 healthy neonatal Wistar rats have randomly divided into three groups: control group received breastmilk only, treatment group (T1) receiving breast milk + mild-scratched intensity of tahneeq, and T2 group received breastmilk + strong-scratched intensity of tahneeq on the palatal and gingival mucosa immediately after birth.  Seven neonatal Wistar rats in all groups were then sacrificed in three hours after birth and days 1, 5, 7, 13, and 30 treatment. IL-12 expression in the palatal and gingival mucosa was determined using immunohistochemical staining, and blood CD8⁺ T-lymphocytes were quantified using a flow cytometer. One way ANOVA was used to analyze the percentage of IL-12 and CD8⁺ T-lymphocytes among neonatal Wistar rat groups.  The T1 and T2 newborn rat groups had significantly higher IL-12 expression than the control group (p<0.001). The increased IL-12 expression in T2 groups significantly increased (p<0.001) compared to the IL-12 expression in the T1 and control groups. The percentage of  CD8⁺ T lymphocytes in all neonatal rat groups increased on three hours after birth and day 30 treatment but remained constant on days 5 and 7 treatment and decreased on day 13 treatment. At 5, 13, and 30^th days treatment,  the percentage of CD8⁺ T lymphocytes in T1 and T2 neonatal rat groups was significantly higher (p<0.05) than that in the control group. In conclusion, the impact on systemic CD8⁺ T cells did not influence by the depth of the scratch. Both mild and strong tahneeq increased the systemic CD8⁺ T-lymphocytes in neonatal Wistar rats. The roles of anti-inflammatory cytokines and Treg cells should be further investigated to unravel those different results for the development of mucosal immunity in neonates.     

Adult-like anti-mycobacterial T cell and in vivo dendritic cell responses following neonatal immunization with Ag85B-ESAT-6 in the IC31 adjuvant

Background

With the exception of some live vaccines, e.g. BCG, subunit vaccines formulated with “classical” adjuvants do not induce similar responses in neonates as in adults. The usual neonatal profile is characterized by lower levels of TH1-associated biomarkers. This has hampered the development of new neonatal vaccines for diseases that require early protection. Tuberculosis is one of the major targets for neonatal immunization. In this study, we assessed the immunogenicity of a novel candidate vaccine comprising a mycobacterial fusion protein, Ag85B-ESAT-6, in a neonatal murine immunization model.

Methods/Findings

The Ag85B-ESAT-6 fusion protein was formulated either with a classical alum based adjuvant or with the novel IC31® adjuvant. Following neonatal or adult immunization, 3 parameters were studied in vivo: (1) CD4⁺ T cell responses, (2) vaccine targeting/activation of dendritic cells (DC) and (3) protection in a surrogate mycobacterial challenge model. Conversely to Alum, IC31® induced in both age groups strong Th1 and Th17 responses, characterized by multifunctional T cells expressing IL-2 and TNF-α with or without IFN-γ. In the draining lymph nodes, a similarly small number of DC contained the adjuvant and/or the antigen following neonatal or adult immunization. Expression of CD40, CD80, CD86 and IL-12p40 production was focused on the minute adjuvant-bearing DC population. Again, DC targeting/activation was similar in adults and neonates. These DC/T cell responses resulted in an equivalent reduction of bacterial growth following infection with M. bovis BCG, whereas no protection was observed when Alum was used as adjuvant.

Conclusion

Neonatal immunization with the IC31®- adjuvanted Ag85B-ESAT-6 subunit vaccine elicited adult-like multifunctional protective anti-mycobacterial T cell responses through the induction of an adult pattern of in vivo DC activation.     

Estradiol distribution and penetration in rat skin after topical application,studied by high resolution autoradiography

Summary Transdermal pathways and targets in the skin for estradiol were investigated using dry-mount autoradiography.³H-estradiol-17 was applied at doses of 30.1 pmol, 120.4 pmol and 301 pmol/cm² to shaved rat skin in the dorsal neck region. Vehicles were DMSO, ethylene glycol or sesame oil. After 2 h of topical treatment with 30.1 pmol³H-estradiol×cm^–2 dissolved in DMSO a distinct cellular distribution was apparent. Target cells with concentrations of radioactivity were found in epidermis, sebaceous glands, dermal papillae of hair and fibroblasts. After treatment with 120.4 and 301 pmol/cm², a penetration gradient of radioactivity was recognizable however it masked specific cellular and subcellular uptake. The stratum corneum accumulated and retained radioactivity, apparently forming a depot for the hormone. Strong concentration and retention of the hormone was conspicious in sebaceous glands for more than 24 h, suggesting that sebaceous glands serve as a second storage site for the hormone. In all autoradiograms two penetration pathways to the dermis were visible: one through the stratum corneum and epidermis, the other through the hair canals and hair sheaths.This work was supported by US PHS grant NS09914     

Selective beta-adrenoceptor antagonism of induced formation of 14C-N-acetylserotonin in rat pineal glands in organ culture.

Stimulation of β-adrenoceptors in cultured rat pineal glands increased the formation of (¹⁴C)-N-acetylserotonin (NAcS) from (¹⁴C)-serotonin. The non-selective β-adrenoceptor antagonist dl-propranolol and the selective β₁-adrenoceptor antagonist practolol both decreased the response to the directly acting β-agonist terbutaline 2×10^?4 M, when measured as the amount of (¹⁴C)-NAcS released into culture medium during a 24 h period. A 1,000 times higher concentration was required in the medium using practolol than propranolol to decrease (¹⁴C)-NAcS formation 50% as compared to the level reached using terbutaline 2×10^?4 M by itself.Two different selective β₂-adrenoceptor antagonists were tried: butoxamine (0.05 mM–0.10 mM) and H 35/25 (0.01 mM–0.25 mM). Butoxamine was without effect in the concentrations tested and H 35/25 either did not affect or in the lowest concentration potentiated terbutaline induced (¹⁴C)-NAcS formation. The results indicate that the rat pineal gland β-adrenoceptors studied in organ culture respond similar to the β₁-adrenoceptor subgroup.     

Circulating Endothelial Progenitor Cells Decrease in Infants with Bronchopulmonary Dysplasia and Increase after Inhaled Nitric Oxide

Background

Impairment of endothelial progenitor cells (EPCs) has been shown to contribute to the development of bronchopulmonary dysplasia (BPD). In the current study, the relationship between EPC changes of after birth and the development of BPD was investigated, and the effects of inhaled nitric oxide (iNO) on EPCs were evaluated.

Methods

Sixty infants with a gestational age of less than 32 weeks and a birth weight of less than 1500 g were studied. NO was administered to infants who were receiving mechanical ventilation or CPAP for at least 2 days between the ages of 7 and 21 days. EPC level was determined by flow cytometry at birth, 7, 21 and 28 days of age and 36 weeks’ postmenstrual age (PMA), before and after the iNO treatment. Plasma concentrations of vascular endothelial growth factor (VEGF), stromal cell-derived factor-1 and granulocyte-macrophage colony-stimulating factor were determined via immunochemical assay.

Results

Twenty-five neonates developed BPD, 35 neonates survived and did not develop BPD. EPC level was decreased on day 7 and 21 in infants who later developed BPD compared with infants that did not develop BPD. From birth to 21 days of age, BPD infants had a persistently lower VEGF concentration compared with non-BPD infants. No difference was found between the two groups at day 28 or 36 weeks PMA. In infants that later developed BPD, iNO raised the KDR⁺CD133⁺ and CD34⁺KDR⁺CD133⁺ EPC numbers along with increasing the level of plasma VEGF.

Conclusion

EPC level was reduced at 7 days of age in infants with BPD, and iNO increased the EPC number along with increasing the level of VEGF. Further studies are needed to elucidate the mechanism leading to the decrease of EPCs in infants with BPD and to investigate the role of iNO treatment in the prevention of BPD.     

Cytokine and chemokine responses to helminth and protozoan parasites and to fungus and mite allergens in neonates,children, adults,and the elderly

Background

In rural sub-Saharan Africa, endemic populations are often infected concurrently with several intestinal and intravascular helminth and protozoan parasites. A specific, balanced and, to an extent, protective immunity will develop over time in response to repeated parasite encounters, with immune responses initially being poorly adapted and non-protective. The cellular production of pro-inflammatory and regulatory cytokines and chemokines in response to helminth, protozoan antigens and ubiquitous allergens were studied in neonates, children, adults and the elderly.

Results

In children schistosomiasis prevailed (33%) while hookworm and Entamoeba histolytica/E. dispar was found in up to half of adults and the elderly. Mansonella perstans filariasis was only present in adults (24%) and the elderly (25%). Two or more parasite infections were diagnosed in 41% of children, while such polyparasitism was present in 34% and 38% of adults and the elderly. Cytokine and chemokine production was distinctively inducible by parasite antigens; pro-inflammatory Th2-type cytokine IL-19 was activated by Entamoeba and Ascaris antigens, being low in neonates and children while IL-19 production enhanced “stepwise” in adults and elderly. In contrast, highest production of MIP-1delta/CCL15 was present in neonates and children and inducible by Entamoeba-specific antigens only. Adults and the elderly had enhanced regulatory IL-27 cytokine responses, with Th2-type chemokines (MCP-4/CCL13, Eotaxin-2/CCL24) and cytokines (IL-33) being notably inducible by helminth- and Entamoeba-specific antigens and fungus-derived allergens. The lower cellular responsiveness in neonates and children highlighted the development of a parasite-specific cellular response profile in response to repeated episodes of exposure and re-infection.

Conclusions

Following repeated exposure to parasites, and as a consequence of host inability to prevent or eliminate intestinal helminth or protozoa infections, a repertoire of immune responses will evolve with lessened pro-inflammatory and pronounced regulatory cytokines and chemokines; this is required for partial parasite control as well as for preventing inadequate and excessive host tissue and organ damage.