Microbial ligand-independent regulation of lymphopoiesis by NOD1

Aberrant differentiation of progenitor cells in the hematopoietic system is known to severely impact host immune responsiveness. Here we demonstrate that NOD1, a cytosolic innate sensor of bacterial peptidoglycan, also functions in murine hematopoietic cells as a major regulator of both the generation and differentiation of lymphoid progenitors as well as peripheral T lymphocyte homeostasis. We further show that NOD1 mediates these functions by facilitating STAT5 signaling downstream of hematopoietic cytokines. In steady-state, loss of NOD1 resulted in a modest but significant decrease in numbers of mature T, B and natural killer cells. During systemic protozoan infection this defect was markedly enhanced, leading to host mortality. Lack of functional NOD1 also impaired T cell-dependent anti-tumor immunity while preventing colitis. These findings reveal that, in addition to its classical role as a bacterial ligand receptor, NOD1 plays an important function in regulating adaptive immunity through interaction with a major host cytokine signaling pathway.

IFNs Reset the Differential Capacity of Human Monocyte Subsets to Produce IL-12 in Response to Microbial Stimulation

Human primary monocytes are composed of a minor, more mature CD16+(CD14low/neg) population and a major CD16neg(CD14+) subset. The specific functions of CD16+ versus CD16neg monocytes in steady state or inflammation remain poorly understood. In previous work, we found that IL-12 is selectively produced by the CD16+ subset in response to the protozoan pathogen, Toxoplasma gondii In this study, we demonstrated that this differential responsiveness correlates with the presence of an IFN-induced transcriptional signature in CD16+ monocytes already at baseline. Consistent with this observation, we found that in vitro IFN-γ priming overcomes the defect in the IL-12 response of the CD16neg subset. In contrast, pretreatment with IFN-γ had only a minor effect on IL-12p40 secretion by the CD16+ population. Moreover, inhibition of the mTOR pathway also selectively increased the IL-12 response in CD16neg but not in CD16+ monocytes. We further demonstrate that in contrast to IFN-γ, IFN-α fails to promote IL-12 production by the CD16neg subset and blocks the effect of IFN-γ priming. Based on these observations, we propose that the acquisition of IL-12 responsiveness by peripheral blood monocyte subsets depends on extrinsic signals experienced during their developmental progression in vivo. This process can be overridden during inflammation by the opposing regulatory effects of type I and II IFN as well as the mTOR inhibition.

Source and fate of nitrate in contaminated groundwater systems: Assessing spatial and temporal variations by hydrogeochemistry and multiple stable isotope tools

Intensive farming usually imply a degradation of groundwater resources worldwide. In particular, nitrate concentrations exceeding the 50 mg L^-1 limit established for drinking water pose the human health at risk. Therefore, assessing the impact of farming on groundwater, in terms of space and time, is of fundamental importance for policy decision makers and land managers. This study was aimed at assessing the nitrate source and fate in groundwater by combining hydrogeochemical and isotopic tools. The study area is located in the coastal plain of Arborea (Italy), a nitrate vulnerable zone (NVZ) due to intensive farming and animal husbandry (28,000 bovine livestock units). This area represents Mediterranean environments where groundwater resources are of relevant importance. In order to assess the present level of groundwater contamination and evaluate temporal variations, 6 hydrogeochemical surveys were carried out bimonthly at 13 sampling sites located in an area of 6 km². Additional samples were collected in specific surveys (82 water samples in total). The physical-chemical parameters, nitrogen species concentrations, major and minor components were determined, together with the boron, hydrogen, oxygen, nitrogen, and sulfur isotopic delta values. Results showed that groundwater samples were of meteoric origin, as indicated by the δ²H and δ¹⁸O_H2O values. The groundwater showed near-neutral pH (6.8-7.9) and different values of redox potential (0.2 ÷ 0.5 V), dissolved oxygen (2 ÷ 6 mg L^-1), electrical conductivity (0.8 ÷ 2.1 mS cm^-1) and chemical composition (sodium-chloride ÷ calcium-bicarbonate). Nitrate was not homogeneously distributed in groundwater, being observed a large range of concentrations, from <1 up to 162 mg L^-1. The above differences reflected the variability of groundwater circulation at small scale, which in turn controlled the interaction of water with different sediments (sands and/or clays). The shallow wells (about 5 m depth), screened in groundwater interacting mainly with sands, showed marked variations under the monitoring period, with nitrate peaks reflecting high leaching of nitrate in correspondence of fertilization and irrigation periods. The deeper wells (15-37 m depth) showed high to moderate nitrate when screened in sandy aquifer, whereas they had very low nitrate and relatively high ammonium (up to 1.8 mg L^-1) when clay layers were intercepted. Trends of δ¹⁵N and δ¹⁸O_NO3 values in the nitrate of shallow groundwater were related to the nitrate concentration observed over the monitored period. This dual isotope systematic showed a likely source of nitrate in groundwater from either manure or sewage. The δ¹¹B signature coupled to δ¹⁵N values clearly identified the manure as the predominant source of nitrate in the shallow and deep groundwater at Arborea. Relative enrichments in heavy nitrogen coupled to high concentrations of nitrate in groundwater were mainly attributed to volatilization processes occurring during the storage of animal wastes prior to application on the soil. Mixing of groundwater with seawater was not recognized, whereas mixing between shallow and deep groundwater may have occurred locally. Natural attenuation of nitrate contamination was observed in the deep groundwater interacting with lagoon clays rich in organic matter. Heterotrophic denitrification processes were highlighted by relatively high δ¹⁵N, δ¹⁸O_NO3, δ³⁴S and δ¹⁸O_SO4 values in association with low SO₄^2-/Cl^- and high HCO₃^-/SO₄^2- molar ratios observed in the groundwater with low concentration of nitrate. Results of this study showed that site-specific investigations are required for designing the best practices aimed at preserving groundwater resources under Mediterranean conditions. The spreading of animal waste on soils affects groundwater systems and likely extends over long time, strongly depending on the time lag of nutrient transport from source areas to receptor wells. Therefore, adequate monitoring of groundwater quality is required in areas of intensive farming.

Inhibition of mTORC1 activity is required for the IL-12p40 response of classical CD16neg CD14+ primary human monocytes to Toxoplasma gondii

Primary human monocytes produce IL-12 and TNF in response to live Toxoplasma gondii tachyzoytes by a mechanism requiring parasite phagocytosis. Interestingly, in contrast to the patrolling CD16+ CD14+ subset, monocytes belonging to the major CD16neg CD14+ subset fail to secrete IL-12 and TNF following T. gondii exposure. Here we show that the CD16neg CD14+ subset, nevertheless, upregulates Il12b mRNA and thus is able to sense the parasite. In addition, we demonstrate that priming with IFNg, but not IFNa, enables CD16negCD14+ monocytes to produce IL-12 protein in response to T. gondii. This effect of IFNg priming was not due to augmented phagocytosis and was not associated with altered rates of glycolysis, oxygen consumption, or increased Il12b mRNA expression. To test the possible role of IFNγ on cytokine translation, we evaluated the requirement for mTOR (mTORC1/2) pathway, a key regulator of protein synthesis. The T. gondii-induced IL-12 response of IFNγ primed CD16neg monocytes was inhibited by Torin, an inhibitor of mTORC2, but surprisingly not by the classical mTORC1 inhibitor Rapamycin. Because mTORC2 has been shown to downregulate mTORC1 activity, we hypothesized that the priming effect of IFNg might result from the upregulation of mTORC2 resulting in suppressed mTORC1. Indeed, in the absence of IFNγ, suppression of mTORC1 in CD16neg monocytes with Rapamycin enhanced IL-12 secretion. Taken together, our results suggest that classical CD16neg CD14+ monocytes fail to secrete IL-12 in response to T. gondii due to increased mTORC1 activity, which can be reversed directly by Rapamycin or indirectly through stimulation of mTORC2 by IFNγ priming.

Prenatal diagnosis and outcome of fetal posterior fossa fluid collections

OBJECTIVE

To evaluate the accuracy of fetal imaging in differentiating between diagnoses involving posterior fossa fluid collections and to investigate the postnatal outcome of affected infants.

METHODS

This was a retrospective study of fetuses with posterior fossa fluid collections, carried out between 2001 and 2010 in two referral centers for prenatal diagnosis. All fetuses underwent multiplanar neurosonography. Parents were also offered fetal magnetic resonance imaging (MRI) and karyotyping. Prenatal diagnosis was compared with autopsy or postnatal MRI findings and detailed follow-up was attempted by consultation of medical records and interview with parents and pediatricians.

RESULTS

During the study period, 105 fetuses were examined, at a mean gestational age of 24 (range, 17-28) weeks. Sonographic diagnoses (Blake's pouch cyst, n = 32; megacisterna magna, n = 27; Dandy-Walker malformation, n = 26; vermian hypoplasia, n = 17; cerebellar hypoplasia, n = 2; arachnoid cyst, n = 1) were accurate in 88% of the 65 cases in which confirmation was possible. MRI proved more informative than ultrasound in only 1/51 cases. Anatomic anomalies and/or chromosomal aberrations were found in 43% of cases. Blake's pouch cysts and megacisterna magna underwent spontaneous resolution in utero in one third of cases and over 90% of survivors without associated anomalies had normal developmental outcome at 1-5 years. Isolated Dandy-Walker malformation and vermian hypoplasia were associated with normal developmental outcome in only 50% of cases.

CONCLUSION

Prenatal neurosonography and MRI are similarly accurate in the categorization of posterior fossa fluid collections from mid gestation. Blake's pouch cyst and megacisterna magna are risk factors for associated anomalies but when isolated have an excellent prognosis, with a high probability of intrauterine resolution and normal intellectual development in almost all cases. Conversely, Dandy-Walker malformation and vermian hypoplasia, even when they appear isolated antenatally, are associated with an abnormal outcome in half of cases.

Prenatal diagnosis and outcome of partial agenesis and hypoplasia of the corpus callosum

OBJECTIVE

To present antenatal sonographic findings and outcome of fetuses with hypoplasia or partial agenesis of the corpus callosum.

METHODS

The database of our ultrasound laboratory was searched retrospectively for cases of hypoplasia or partial agenesis of the corpus callosum suspected at antenatal neurosonography between 1998 and 2008 and confirmed by pathology or postnatal neuroimaging. In surviving infants, clinical follow-up had been arranged to assess neurodevelopmental outcome.

RESULTS

Nineteen fetuses with callosal underdevelopment were identified at a median gestational age of 22 (range, 21-33) weeks and confirmed at follow-up, including 14 with partial agenesis and five with hypoplasia. Among the 14 fetuses with partial agenesis, there were additional brain findings in 10, including two with absent cavum septi pellucidi, four with mild isolated ventriculomegaly and four with cerebellar abnormalities, two of which also had ventriculomegaly. Pregnancy was terminated electively in seven of the cases with partial agenesis and there was one neonatal death. Among the six surviving infants, neurodevelopmental outcome was appropriate for age in three at follow up, including two cases with isolated partial agenesis of the corpus callosum. Among the five fetuses with prenatally diagnosed callosal hypoplasia, additional anomalies were present in four. Two cases were terminated electively and three were alive at the time of writing, with a median age of 3 years. Among them, apparently normal neurological development was observed in only one case.

CONCLUSIONS

An antenatal diagnosis of callosal underdevelopment is possible by expert sonography. There is often association with other major anomalies. However, even in fetuses with apparently isolated findings, the prognosis is uncertain.

Prenatal diagnosis of open and closed spina bifida

OBJECTIVE

To identify criteria useful for differentiating closed from open spina bifida antenatally.

PATIENTS AND METHODS

A retrospective study of cases of spina bifida diagnosed in a referral center between 1997 and 2004.

RESULTS

Of 66 cases of fetal spina bifida diagnosed at a median gestational age of 21 (range, 16-34) weeks, detailed follow-up was available for 57. Of these, open defects were found in 53 (93.0%) and closed defects in four (7.0%). Closed spina bifida was associated in two cases with a posterior cystic mass with thick walls and a complex appearance, while in two cases the spinal lesion could not be clearly differentiated from an open defect, particularly at mid-gestation. Open spina bifida was always associated with typical alterations of cranial anatomy, including the so-called 'banana' and 'lemon' signs, while in closed spina bifida the cranium was unremarkable. When the data were available, levels of amniotic fluid alpha-fetoprotein were always abnormally elevated with open spina bifida and within normal limits with closed forms.

CONCLUSION

In this study 7% of cases of spina bifida diagnosed in utero were closed. The differentiation between open and closed forms is best shown by the sonographic demonstration of abnormal or normal cranial anatomy.

Diagnosis of midline anomalies of the fetal brain with the three-dimensional median view

OBJECTIVE

To investigate the effectiveness of a simplified approach to the evaluation of the midline structures of the fetal brain using three-dimensional (3D) ultrasound.

METHODS

Sonographic examinations were performed in normal fetuses and in cases with anomalies involving the midline cerebral structures. Two-dimensional (2D) median planes were obtained by aligning the transducer with the anterior fontanelle and midline sutures by either transabdominal or transvaginal scans. Median planes were also reconstructed using 3D ultrasonography from volumes acquired from transabdominal axial planes of the fetal head (3D median planes), by either multiplanar analysis of static volumes or volume contrast imaging in the coronal plane (VCI-C). 2D and 3D median planes were compared qualitatively and quantitatively by measuring the corpus callosum and cerebellar vermis.

RESULTS

2D median planes could be visualized in 54/56 normal fetuses. 3D median planes were obtained in all, usually more easily and rapidly. There was a good correlation between 2D and 3D images. Measurements of the corpus callosum and cerebellar vermis were highly correlated, with mean variations of 6% and 14%, respectively. The abnormal group included 13 fetuses (five with partial or complete agenesis of the corpus callosum, six with posterior fossa malformations, two with a combination of these two anomalies). In all cases the diagnosis could be made by both 2D and 3D views and was always confirmed by postnatal investigation. Although 2D median views were of better quality, 3D images were always adequate for diagnosis, both in normal and abnormal fetuses.

CONCLUSIONS

3D median planes are obtained more easily than 2D ones, and allow an accurate diagnosis of normal cerebral anatomy and anomalies. The 3D approach may be valuable particularly for rapid assessment of fetal cerebral anatomy in standard examinations.

Difficult early sonographic diagnosis of absence of the fetal septum pellucidum

Standard sonographic views of the brain obtained along the axial planes at mid-gestation failed to identify absence of the septum pellucidum in two consecutive fetuses. It was presumably the close proximity of the walls of the lateral ventricles that generated an artifact resembling a normal cavum septi pellucidi. In one of these fetuses, septo-optic dysplasia was confirmed by magnetic resonance demonstration of hypoplastic optic tracts. In the other fetus, isolated absence of the septum pellucidum was the final diagnosis. Standard axial scans are unreliable in predicting absence of the septum pellucidum in the mid-trimester fetus when the lateral ventricles are normal in size.

Asthma-like symptoms, atopy, and bronchial responsiveness in furniture workers

OBJECTIVES

To study the role of individual and occupational risk factors for asthma in furniture workers.

METHODS

296 workers were examined (258 men, 38 women) with a questionnaire of respiratory symptoms and diseases, baseline spirometry, bronchial provocative test with methacholine, and skin prick tests. Non-specific bronchial hyperreactivity was defined as when a provocative dose with a fall of 20% in forced expiratory volume in 1 second (PD20FEV1) was < 0.8 mg and atopy in the presence of at least one positive response to skin prick tests. Workers were subdivided into spray painters (exposed to low concentrations of diisocyanates and solvents), woodworkers (exposed to wood dusts), and assemblers (control group).

RESULTS

The prevalences of attacks of shortness of breath with wheezing and dyspnoea were higher in spray painters (13.5% and 11.5% respectively) than in woodworkers (7.7% and 6.3%) or in assemblers (1.6% and 1.6%); prevalences of chronic cough, asthma, and rhinitis were also slightly but not significantly higher in spray painters and in woodworkers than in assemblers. The difference in the prevalence of respiratory symptoms among the job titles was due to the atopic subjects, who showed a higher prevalence of chronic cough, wheeze, shortness of breath with wheeze, dyspnoea, and asthma in spray painters than in the other groups. The prevalence of non-specific bronchial hyperreactivity in subjects who performed bronchial provocative tests was 17.7%, with no significant difference among groups. Asthma symptoms were significantly associated with non-specific bronchial hyperreactivity. Asthma-like symptoms plus non-specific bronchial hyperreactivity was found in 4% of assemblers, 10% of woodworkers, and 13.3% of spray painters (chi 2 = 2.6, NS). Multiple logistic analysis taking into account individual (smoke, atopy, age) and occupational (job titles) risk factors confirmed that spray painters had higher prevalence of chronic cough than assemblers, and a trend in increasing the prevalence of shortness of breath with wheeze, dyspnoea, and asthma.

CONCLUSIONS

Painters in the furniture industry, particularly atopic subjects, are at higher risk of asthma-like symptoms than other job titles. In these workers asthma-like symptoms are more sensitive than non-specific bronchial hyperreactivity in detecting a negative effect of the occupational exposure.

Venobronchial fistula: an unusual early complication after central venous catheterization

Venobronchial fistula is a rare complication of long-term central venous catheterization. We present the uncommon occurrence of a venobronchial fistula as an acute complication of central venous catheterization during open heart surgery. The factors responsible for this unusual complication and the methods to prevent it are discussed.

[Acute iatrogenic myopathy during treatment of status asthmaticus. Our experience and review of the literature]

CASE REPORT

A young man was admitted to the ICU for acute asthmatic respiratory failure. He was sedated with propofol, curarized with pancuronium and put on mechanical ventilation for 15 day because of the persistent asthmatics crisis. Drug therapy for asthma included high-dose corticosteroids. When sedation and paralysis were stopped, the patient, that was fully conscious, showed flaccid quadriplegia. A muscular biopsy showed elective loss of the myosin thick filaments. Electrophysiologic evaluation was compatible with both neurologic or muscular pathology. The evolution of the disease was good; a drop-out performed 5 months later showed a complete motor recovery.

DISCUSSION

This case report confirms that in some patients, intensive treatment of status asthmaticus may cause myopathy. Only recently this myopathy has been correlated to an interaction between steroids and neuromuscular blockers. Many experimental and clinical observations suggest a negative interaction between steroids and non-depolarizing curare derivatives. In the case reported here, diagnosis was based on electrophysiologic examination and above all on muscular biopsy.

CONCLUSION

The occurrence of an acute toxic myopathy should always be taken into account, considering the high number of patients admitted with respiratory failure requiring steroid treatment and curare administrative for mechanical ventilation. It therefore seems reasonable to reduce steroid therapy as soon as possible with a periodic suspension of curare administration. Curare usage should be critically evaluated. Some basic examination such as serum CPK monitoring should allow early detection of muscular damage.

Blood markers of early and late airway responses to allergen in asthmatic subjects. Relationship with functional findings

We evaluated the relationship between blood markers of mast-cell (plasma histamine and serum level of heat-stable neutrophil chemotactic activity [NCA]) and eosinophil (serum eosinophil cationic protein [ECP]) activation during early airway response (EAR) and late airway response (LAR) to allergen inhalation in 24 asthmatic subjects. After EAR, 14 subjects showed significant LAR (FEV1 fall: > or = 25%), while 10 subjects showed equivocal LAR (FEV1 fall: 15-20%). A significant increase from baseline value was observed in plasma histamine and in serum NCA during both EAR and LAR, while serum ECP significantly increased only during LAR. The sensitivity of different markers to detect significant FEV1 fall during EAR and LAR was low, except for NCA. Changes in blood mediators were similar in both groups with significant and equivocal LAR. There was a significant relationship between the increase in NCA during EAR and the severity of LAR. Stepwise regression between changes in different blood markers showed a significant relationship between histamine increase during EAR and ECP increase during LAR. Thus, serum NCA is a more sensitive marker of EAR and LAR than plasma histamine and serum ECP, and its increase during EAR seems predictive of the severity of the subsequent LAR.

Tolerance to the protective effect of salmeterol on allergen challenge

Long-term treatment with inhaled beta 2-agonists may be associated with a deterioration in asthma control, potentially due to tolerance. Regular use of short-acting beta 2-agonists has been shown to induce tolerance to allergen or adenosine 5'-monophosphate challenge. The aim of the study was to detect the efficacy of a single dose and a short-term treatment with salmeterol, a long-acting beta 2-agonist, to protect against early asthmatic reaction (EAR) to allergen. Eight subjects with mild allergic asthma underwent two treatment periods in which subjects performed an allergen challenge (specific bronchial provocation test) protected by a single dose (50 micrograms) of salmeterol (Salm-1) followed by a second specific bronchial provocation test after regular treatment with salmeterol for 1 week (Salm-2), or a single dose of placebo (Plac-1) and regular treatment (1 week) with placebo (Plac-2). Each subject performed both treatments in a randomized order. Each time allergen challenge was performed 1 h after last drug inhalation and it was stopped when the same provocative dose of allergen of a previous screening allergen challenge was achieved. The maximum decrease in FEV1 and area under curve in the first hour after allergen inhalation were significantly lower in Salm-1 (max delta FEV1 %, median [range]: 4%[0 to 9]) with respect to Salm-2, Plac-1, Plac-2 (24%[13 to 38], 31%[19 to 50], 30%[6 to 44], respectively, p < 0.001); there was no difference among Salm-2, Plac-1 and Plac-2. In Salm-1, all subjects were protected against EAR, whereas in Salm-2 only 2 subjects showed a partial protection. In conclusion the protective effect of a single dose of salmeterol against allergen-induced EAR was lost after regular treatment with salmeterol for 1 week. The clinical relevance of this mechanism remains to be elucidated.