Physiological reactivity to stress and parental support: comparison of clinical and non‐clinical adolescents

An Alarm Stress Task was developed to study affect regulation in the context of parent–child interactions in adolescents (mean age = 12.72, standard deviation = 2.06) with (n = 20) and without (n = 20) mental health problems. Changes in heart rate (HR), preejection period (PEP) and respiratory sinus arrhythmia (RSA) were used as indicators of affect regulation. HR increased, and PEP and RSA decreased significantly in reaction to a suggested failure on a simple task, indicating that this procedure induced affective arousal in adolescents. During reunion with the parent, RSA increased significantly. Support seeking on reunion was associated with stronger parasympathetic reactivity during stress and reunion, consistent with the model that the parasympathetic system is involved when affect is regulated by social engagement. Quality of parent–adolescent interactive behaviour was overall lower in the clinical sample. Individual and relationship‐based processes of affect regulation may be simultaneously assessed, highlighting the continuing importance of the parent–child relationship in adolescence for affect regulation and mental health. Copyright © 2008 John Wiley & Sons, Ltd.     

Pneumolysin released during Streptococcus pneumoniae autolysis is a potent activator of intracellular oxygen radical production in neutrophils

Streptococcus pneumoniae is a major cause of otitis media, pneumonia, meningitis, and septicemia in humans. The host defense against this pathogen largely depends on bacterial killing by neutrophils. A peculiar property of pneumococci is their tendency to undergo autolysis, i.e., autoinduced disruption of the bacterial cell wall mediated by activation of the enzyme LytA, under stationary growth conditions. LytA is a virulence factor, but the molecular background for this has not been fully clarified. Here we examine how bacterial compounds released upon autolysis affect the production of reactive oxygen species (ROS) in neutrophils. We found that the S. pneumoniae strains A17 and D39 induced activation of the NADPH oxidase and the production of ROS in human neutrophils and that this activation was blocked when LytA was inactivated. The ROS-inducing bacterial substance released from autolyzed bacteria was identified as the cytoplasmic toxin pneumolysin. Further screening of clinical pneumococcal strains of various sero- and genotypes revealed that selected strains expressing toxins with reduced pneumolysin-dependent hemolytic activity had decreased abilities to induce ROS in neutrophils. Furthermore, a mutated form of purified pneumolysin lacking hemolytic and complement binding functions (PdT) did not induce any oxygen radical production. The ROS produced in response to pneumolysin formed mainly intracellularly, which may explain why this production was not detected previously. ROS released intracellularly may function as signaling molecules, modifying the function of neutrophils in bacterial defense.     

Clinical and molecular genetics of patients with the Carney-Stratakis syndrome and germline mutations of the genes coding for the succinate dehydrogenase subunits SDHB, SDHC, and SDHD

Gastrointestinal stromal tumors (GISTs) may be caused by germline mutations of the KIT and platelet-derived growth factor receptor-alpha (PDGFRA) genes and treated by Imatinib mesylate (STI571) or other protein tyrosine kinase inhibitors. However, not all GISTs harbor these genetic defects and several do not respond to STI571 suggesting that other molecular mechanisms may be implicated in GIST pathogenesis. In a subset of patients with GISTs, the lesions are associated with paragangliomas; the condition is familial and transmitted as an autosomal-dominant trait. We investigated 11 patients with the dyad of 'paraganglioma and gastric stromal sarcoma'; in eight (from seven unrelated families), the GISTs were caused by germline mutations of the genes encoding subunits B, C, or D (the SDHB, SDHC and SDHD genes, respectively). In this report, we present the molecular effects of these mutations on these genes and the clinical information on the patients. We conclude that succinate dehydrogenase deficiency may be the cause of a subgroup of GISTs and this offers a therapeutic target for GISTs that may not respond to STI571 and its analogs.     

Cutis laxa,exocrine pancreatic insufficiency and altered cellular metabolomics as additional symptoms in a new patient with ATP6AP1-CDG

Congenital disorders of glycosylation (CDG) are genetic defects in the glycoconjugate biosynthesis. > 100 types of CDG are known, most of them cause multi-organ diseases. Here we describe a boy whose leading symptoms comprise cutis laxa, pancreatic insufficiency and hepatosplenomegaly. Whole exome sequencing identified the novel hemizygous mutation c.542 T > G (p.L181R) in the X-linked ATP6AP1, an accessory protein of the mammalian vacuolar H⁺-ATPase, which led to a general N-glycosylation deficiency. Studies of serum N-glycans revealed reduction of complex sialylated and appearance of truncated diantennary structures. Proliferation of the patient's fibroblasts was significantly reduced and doubling time prolonged. Additionally, there were alterations in the fibroblasts' amino acid levels and the acylcarnitine composition. Especially, short-chain species were reduced, whereas several medium- to long-chain acylcarnitines (C14-OH to C18) were elevated. Investigation of the main lipid classes revealed that total cholesterol was significantly enriched in the patient's fibroblasts at the expense of phophatidylcholine and phosphatidylethanolamine. Within the minor lipid species, hexosylceramide was reduced, while its immediate precursor ceramide was increased. Since catalase activity and ACOX3 expression in peroxisomes were reduced, we assume an ATP6AP1-dependent impact on the β-oxidation of fatty acids. These results help to understand the complex clinical characteristics of this new patient.     

Anandamide produced by Ca2+-insensitive enzymes induces excitation in primary sensory neurons

The endogenous lipid agent N-arachidonoylethanolamine (anandamide), among other effects, has been shown to be involved in nociceptive processing both in the central and peripheral nervous systems. Anandamide is thought to be synthesised by several enzymatic pathways both in a Ca²⁺-sensitive and Ca²⁺-insensitive manner, and rat primary sensory neurons produce anandamide. Here, we show for the first time, that cultured rat primary sensory neurons express at least four of the five known Ca²⁺-insensitive enzymes implicated in the synthesis of anandamide, and that application of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-arachidonoyl, the common substrate of the anandamide-synthesising pathways, results in anandamide production which is not changed by the removal of extracellular Ca²⁺. We also show that anandamide, which has been synthesised in primary sensory neurons following the application of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-arachidonoyl induces a transient receptor potential vanilloid type 1 ion channel-mediated excitatory effect that is not inhibited by concomitant activation of the cannabinoid type 1 receptor. Finally, we show that sub-populations of transient receptor potential vanilloid type 1 ion channel-expressing primary sensory neurons also express some of the putative Ca²⁺-insensitive anandamide-synthesising enzymes. Together, these findings indicate that anandamide synthesised by primary sensory neuron via a Ca²⁺-insensitive manner has an excitatory rather than an inhibitory role in primary sensory neurons and that excitation is mediated predominantly through autocrine signalling. Regulation of the activity of the Ca²⁺-insensitive anandamide-synthesising enzymes in these neurons may be capable of regulating the activity of these cells, with potential relevance to controlling nociceptive processing.     

Novel Real-Time PCR Assays Using TaqMan Minor Groove Binder Probes for Identification of Fecal Carriage of Streptococcus bovis/Streptococcus equinus Complex from Rectal Swab Specimens

Real-time PCR based on the recN and gyrB genes was developed to detect four Streptococcus bovis/Streptococcus equinus complex (SBEC) subspecies from rectal swab specimens. The overall prevalence was 35.2%: Streptococcus gallolyticus subsp. gallolyticus (11.1%), S. gallolyticus subsp. pasteurianus (13%), Streptococcus infantarius subsp. coli (20.4%), and S. infantarius subsp. infantarius (11.1%). To conclude, these real-time PCR assays provide a reliable molecular method to detect SBEC pathogenic subspecies from rectal swab specimens.     

Mouse models of asthma: a comparison between C57BL/6 and BALB/c strains regarding bronchial responsiveness, inflammation, and cytokine production

Objective

Animal models of asthma mimic major features of human disease. Since the genetic background of experimental animals might affect hyperresponsiveness and inflammation, we studied its potential influence and the mechanisms leading to differences in strains.

Methods

We applied a mouse model of allergic asthma to BALB/c and C57BL/6 mice.

Results

BALB/c mice displayed greater levels of airway reactivity to methacholine than C57BL/6 mice. Moreover, BALB/c mice exhibited higher numbers of mast cells in lung tissue when compared to C57BL/6. On the contrary, eosinophil and neutrophil counts in bronchoalveolar lavage fluid (BALF) as well as peribronchial eosinophilia were greater in C57BL/6. IL (Interleukin)-4, IL-5, IL-13, and CCL11 levels measured in whole-lung extracts were higher in BALB/c, while, in sharp contrast, CCL11 and CCL5 levels were higher in BALF of C57BL/6 mice.

Conclusions

We observed phenotypic differences between C57BL/6 and BALB/c mice in an asthma model with different distributions of pro-inflammatory cytokines and inflammatory cells.     

Interactions of Serotoninergic,Cholinergic, and Tachykinin‐Containing Nerve Elements in the Rabbit Small Intestine

This report presents novel results on the effects of serotonin (5‐HT) on longitudinal muscle contractions in the rabbit ileum and the interactions of serotonin with some neuronal elements of the myenteric plexus. We showed previously that serotonin‐triggered contractions involved two mechanisms in the rabbit ileum: neuronal excitation (via 5‐HT₂ receptors in the neurons) and direct muscular stimulation (via 5‐HT₄ receptors in the muscle). Here, we focus on the neuronal 5‐HT₂ receptor pathway and report further pharmacological and immunocytochemical data clarifying the details of the mechanisms. We observed that antagonists for neurokinin (NK1 and NK2) receptors partially blocked the serotonin response, but NK3 receptor antagonists had no effect. Pretreatment by atropine (ATR) eliminated the NK1 receptor antagonist resistant contractions. In contrast, the NK1 antagonist did not depress the ATR‐resistant contraction when ATR was added first. 5‐HT₂ receptor agonist‐induced contractions were partially suppressed by ATR, hexamethonium, and NK1 or NK2 receptor antagonists. In conclusion, serotonin acting through 5‐HT₂ receptors could stimulate interneurons and excitatory motor neurons. Immunocytochemical staining revealed an extensive tachykinin‐immunoreactive (IR) network in the myenteric plexus. Approximately 52% of all myenteric neurons were labeled. 5‐HT‐IR fibers could be detected around both choline acetyltransferase‐ and tachykinin‐IR cells, suggesting functional relationships between them. Consistent with our pharmacological observations, we found that immunopositive nerve elements for 5‐HT_2A receptor and double‐labeled immunostaining revealed a remarkable overlap between tachykinin‐IR neurons and 5‐HT_2A‐IR elements. Anat Rec, 2009. © 2009 Wiley‐Liss, Inc.     

Association between maternal weight gain and birth weight

OBJECTIVE: To investigate the association between maternal weight gain and birth weight less than 3,000 g and greater than or equal to 4,000 g in underweight (body mass index [BMI] less than 19.8 kg/m(2)), normal weight (BMI 19.8-26.0 kg/m(2)), overweight (BMI 26.1-29.0 kg/m(2)), and obese (BMI greater than 29.0 kg/m(2)) women, with emphasis on the use of the American Institute of Medicine (IOM) recommendations in Denmark. METHODS: We analyzed data from 2,248 women with singleton, term pregnancies. The relationship between weight gain and risk of birth weight less than 3,000 g and greater than or equal to 4,000 g was examined in the four BMI groups, and use of IOM recommendations was tested by logistic regression analyses. RESULTS: We found an inverse relationship between maternal weight gain and the proportion of infants with a birth weight less than 3,000 g. Birth weight greater than or equal to 4,000 g increased with an increasing weight gain in underweight and normal-weight women, but the association was less apparent in overweight and obese women. Underweight women seemed to benefit from gaining more weight than recommended by the IOM, because the odds ratio (OR) of birth weight less than 3,000 g was 0.3 (95% confidence interval [CI] 0.1-0.9) and the OR was 1.7 for birthweight greater than or equal to 4,000 g (95% CI 0.8-3.6). The normal-weight women had an increased risk of birth weight less than 3,000 g (OR 2.4, 95% CI 1.5-3.7) if weight gain was below the recommended range, and the OR of birth weight greater than or equal to 4,000 g was 1.9 (95% CI 1.5-2.5) when the women gained more than recommended. CONCLUSION: The IOM recommendations may provide a basis for Danish recommendations to pregnant women, although the upper recommended limit for underweight women may have to be increased.