Chemical development of intracellular protein heterodimerizers

Cell activation initiated by receptor ligands or oncogenes triggers complex and convoluted intracellular signaling. Techniques initiating signals at defined starting points and cellular locations are attractive to elucidate the output of selected pathways. Here, we present the development and validation of a protein heterodimerization system based on small molecules cross-linking fusion proteins derived from HaloTags and SNAP-tags. Chemical dimerizers of HaloTag and SNAP-tag (HaXS) show excellent selectivity and have been optimized for intracellular reactivity. HaXS force protein-protein interactions and can translocate proteins to various cellular compartments. Due to the covalent nature of the HaloTag-HaXS-SNAP-tag complex, intracellular dimerization can be easily monitored. First applications include protein targeting to cytoskeleton, to the plasma membrane, to lysosomes, the initiation of the PI3K/mTOR pathway, and multiplexed protein complex formation in combination with the rapamycin dimerization system.

The cumulative effect of small dietary changes may significantly improve nutritional intakes in free-living children and adults

BACKGROUND/OBJECTIVES

The ELPAS (Etude Longitudinale Prospective Alimentation et Santé) study was an 8-month randomized controlled dietary modification trial designed to test the hypothesis that family dietary coaching would improve nutritional intakes and weight control in 2026 free-living children and parents. It resulted in significant nutritional changes, with beneficial effects on body mass index in adults. In these ancillary analyses, we investigated dietary changes throughout the intervention.

SUBJECTS/METHODS

Before the study, modeling analyses were carried out on the French Association Sucre Produits Sucrés Consommation et Communication (ASPCC) food-consumption database to identify the most efficient dietary intervention strategy. During the study, all participants performed monthly three nonconsecutive 24-h dietary recalls: this allowed for measuring changes in the number of servings per day and serving size for each targeted food category throughout the intervention.

RESULTS

Modeling analyses showed that targeting only the 10 main foods contributing to fat and carbohydrate intakes did not allow for reaching the ELPAS nutritional goals. As a result, it was decided to target more foods and to propose several types of dietary advice (such as change in serving size, change in cooking method, food substitution). This strategy led to many appropriate dietary changes during the intervention, but only a few of them reached significance. The mean number of servings per day was indeed significantly modified for only 7% of the targeted food categories in children and 17% in parents. The mean serving size was modified for only 12% of targeted food categories in children and 9% in parents.

CONCLUSIONS

The cumulative effect of small dietary changes may induce significant nutritional improvements, with limited burden for populations.

Thiophenol-Mediated 1,5-Hydrogen Transfer for the Preparation of Pyrrolizidines, Indolizidines, and Related Compounds

The efficient preparation of 1-azabicyclic alkanes is described. Highly functionalized skeletons are prepared in a concise manner using a radical tin-free 1,5-hydrogen transfer-cyclization process. The precursors for the radical reactions are readily assembled either from pyrrolidine/piperidine/hexahydro-1H-azepine or via condensation of a properly designed N-alkylimine with an allenylzinc species.

A concise synthesis of the Pennsylvania Green fluorophore and labeling of intracellular targets with O6-benzylguanine derivatives

We report improved syntheses of the Pennsylvania Green and 4-carboxy-Pennsylvania Green fluorophores; the latter compound was prepared from methyl 4-iodo-3-methylbenzoate in a three-pot process (32% overall yield). Chinese hamster ovary cells expressing O6-alkylguanine-DNA alkyltransferase fusion proteins were treated with Pennsylvania Green and Oregon Green linked to O6-benzylguanine (SNAP-Tag substrates). Analysis of living cells by confocal microscopy revealed that Pennsylvania Green derivatives exhibit substantially higher cell permeability than analogous Oregon Green-derived molecular probes.

Gastroschisis and omphalocele: retrospective study of initial postoperative management in the ICU

AIM OF THE STUDY

The purpose of this study is to describe the management of infants with gastroschisis (G) and omphalocele (O) during the first 7 days after surgery.

METHODS

A retrospective review of all cases of O or G managed at the ICU of the Robert Debré Teaching Hospital between January 1993 and July 2000 was carried out.

PATIENTS

29 infants with G, 15 with O (12 unruptured O [UO] and 3 ruptured O [RO]).

RESULTS

Ventilatory support consisted of conventional mechanical ventilation (46 %) and/or in high-frequency oscillatory ventilation (61 %). After day 4, ventilatory requirements evaluated by mean airway pressure (MAP) differed significantly between G (n = 10/29) and O (n = 7/15; group vs. day of life, p = 0.04). The average of MAP measured on days 5, 6, and 7 was significantly higher in O than in G (14.7 +/- 3.0 versus 10.9 +/- 2.8, p < 0.01, respectively). Volume expansion was required at least once in 90 % of patients. Mean fluid requirements were significantly lower in UO than in G and in RO (41 +/- 31 ml/kg, 91 +/- 73 ml/kg, and 137 +/- 25 ml/kg, respectively; p = 0.02 for each comparison). Patients with G were significantly more likely to receive norepinephrine (59 % vs. 20 %, p = 0.027) than patients with O. Twenty-six infants with G (90 %) and 11 with O (73 %) were discharged alive from ICU.

CONCLUSIONS

Haemodynamic instability can be expected in patients with G or RO, and ventilatory requirements were higher in infants with O than in infants with G during the first week after surgery.

Highly Diastereoselective Formation of Spirocyclic Compounds via 1,5-Hydrogen Transfer: A Total Synthesis of (−)-Erythrodiene

[reaction: see text] A highly stereoselective synthesis of (-)-erythrodiene starting from 4-isopropylcyclohexanone is described. The key reactions are an asymmetric methoxycarbonylation of the starting ketone and a highly diastereoselective radical cascade involving addition of a phenylthiyl radical to a terminal alkyne followed by a 1,5-hydrogen transfer and a 5-exo-cyclization.

[Antenatal corticosteroids: benefits and risks]

A favorable benefit-to-risk ratio is well established for a single dose of antenatal corticosteroids in women at risk of preterm delivery. The efficacy is real with an important decrease of mortality and morbidity. No adverse effects were described after one course. Possible beneficial effects of repeated courses include lower rates of RDS and a decrease in oxygen use, whereas an increasing body of evidence raises the concern of multiple short and long term adverse consequences, principally neurological. It seems rational to prescribe one course of corticosteroids. The indication for a second course should be discussed but multiples courses of this treatment should not be prescribed. We prefer betamethasone over dexamethasone because of the better side profile. Further work is needed to understand the long-term effects of this treatment.

Outbreak of Burkholderia cepacia bacteremia in a pediatric hospital due to contamination of lipid emulsion stoppers

We describe a 7-month outbreak of nosocomial Burkholderia cepacia bacteremia involving eight children in a pediatric hospital and the results of epidemiological investigations. A B. cepacia strain genotypically identical to the blood isolates was recovered from the upper surface of capped rubber stoppers of bottles of a commercial lipid emulsion used for parenteral nutrition.

[Treatment in 2003 of septic shock in children in the first two hours (excluding newborns)]

Despite new understandings in pathophysiology, sepsis mortality remains high in children. Recently, it has been demonstrated that early goal directed therapy may decrease septic shock mortality. The aim of this paper is to propose practical clinical guidelines based on earlier consensus recommendations. Septic shock must be rapidly suspected and early recognized. Bases of treatment are maintenance of adequate oxygenation with use of artificial ventilation if necessary, larger and faster volume resuscitation than recommended before, empiric antibiotherapy and early use of vasopressive agents associated with corticosteroids in particular situations. Treatment efficacy must be regularly assessed during first hours of resuscitation. Taking into account pediatric particularities and results of adult studies, pediatricians who take care of children at beginning of septic shock may reasonably hope to decrease mortality if they keep in mind specific therapeutic goals.

Thiophenol-Mediated Hydrogen Atom Abstraction: An Efficient Tin-Free Procedure for the Preparation of Cyclopentane Derivatives

[reaction: see text] An efficient procedure for running a cascade reaction involving 1,5-abstraction of a hydrogen atom followed by a radical cyclization is reported. Alkenyl radicals are generated from easily available terminal alkynes and thiophenol. This procedure eliminates the need of using the toxic tributyltin hydride and gives a greater amount of radical translocation products.

Un cas de syndrome de Lemierre avec thrombose veineuse jugulaire bilatérale

An adolescent presented with a rhinosinusitis complicated with bilateral jugular veins and left superior ophthalmic vein thrombosis and respiratory distress with pulmonary hypertension. Blood culture was positive for Haemophilus influenzae and sinus puncture for Streptococcus constellatus. Evolution was under control after 1 week of appropriate antibiotherapy, antithrombotic and anti-inflammatory treatment. He had no neurologic, respiratory or ophthalmologic sequelae 6 months later. Despite lack of pharyngitis or isolation of anaerobic species on blood cultures, the picture was considered compatible with Lemierre syndrome. The risk for such a complication should be considered in cases of severe otorhinolaryngologic infection in young adults.

[Severe acute White-Spirit poisoning with pulmonary hypertension]

The Authors report a case of acute White-Spirit poisoning with pulmonary hypertension associated to respiratory distress syndrome.

CASE REPORT

A 14-month-old infant drank an unknown quantity of White-Spirit while his parents were painting. After he spontaneously vomited, he presented a seizure at the emergency department. After a 36 h stay in Pediatric Intensive Care Unit (PICU), acute lung injury required mechanical ventilation and vasoactive support. Cardiac ultrasounds showed pulmonary hypertension, which rapidly resolved with inhaled nitric oxide. The child was discharged of PICU after five days. Respiratory follow-up two months after poisoning was normal.

CONCLUSION

Pulmonary hypertension should be checked for in case of White-Spirit ingestion complicated with severe acute lung injury.