Early expression of mature αß TCR in CD4-CD8- T cell progenitors enables MHC to drive development of T-ALL bearing NOTCH mutations.

During normal T cell development in mouse and human, a low-frequency population of immature CD4-CD8- double-negative (DN) thymocytes expresses early, mature αß T cell antigen receptor (TCR). We report that these early αß TCR+ DN (EADN) cells are DN3b-DN4 stage and require CD3δ but not major histocompatibility complex (MHC) for their generation/detection. When MHC - is present, however, EADN cells can respond to it, displaying a degree of coreceptor-independent MHC reactivity not typical of mature, conventional αß T cells. We found these data to be connected with observations that EADN cells were susceptible to T cell acute lymphoblastic leukemia (T-ALL) transformation in both humans and mice. Using the OT-1 TCR transgenic system to model EADN-stage αß TCR expression, we found that EADN leukemogenesis required MHC to induce development of T-ALL bearing NOTCH1 mutations. This leukemia-driving MHC requirement could be lost, however, upon passaging the tumors in vivo, even when matching MHC was continuously present in recipient animals and on the tumor cells themselves. These data demonstrate that MHC:TCR signaling can be required to initiate a cancer phenotype from an understudied developmental state that appears to be represented in the mouse and human disease spectrum.

Investigation of antibacterial phytochemicals in the bark and leaves of Ficus coronata by high-performance liquid chromatography-electrospray ionization-ion trap mass spectrometry (HPLC-ESI-MS(n) ) and ESI-MS(n).

The ethyl acetate extracts of the bark and leaves of Ficus coronata were separated by column chromatography and the resulting fractions tested for their bioactivity toward methicillin-resistant-Staphylococcus aureus (MRSA) and M. luteus. The bioactive column chromatography fractions were further separated by preparative thin layer chromatography (TLC) and the resulting bands investigated by high-performance liquid chromatography-electrospray ionization-ion trap mass spectrometry (HPLC-ESI-MS(n) ) and ESI-MS(n) . The resulting retention times, molecular masses, their fragmentation patterns, and the chemnet database (www.chemnetbase.com) were then used in the dereplication process by structural elucidation of some of the compounds when compared with known structures of natural origin. Some molecular masses and the corresponding fragmentations were found that did not correlate with any known compounds thus revealing potentially novel natural products that could be investigated on a larger scale and could ultimately find application as new drugs against MRSA and other multidrug-resistant microorganisms. Structures are also proposed for known compounds that have not been previously reported for F. coronata.

The characterisation of coumarins from selected structural classes by electrospray ionisation quadrupole time-of-flight tandem mass spectrometry.

Electrospray ionisation quadrupole time-of-flight tandem mass spectrometry (ESI-QTOF-MS/MS) has been used for characterisation of a selection of naturally occurring and synthetic coumarins from different structural classes. The product ions, suggested in earlier studies by electrospray ionisation ion trap mass spectrometry (ESI-MS(n)), are unequivocally established for the representative coumarins by virtue of accurate mass measurement. Synthetic coumarins that are unsubstituted in the heterocyclic ring give rise to a major product ion by loss of CO(2), whereas those substituted in the heterocyclic ring generally undergo alternative fragmentation releasing neutral species such as ketene or methyl ketene. Naturally occurring coumarins, unsubstituted in the heterocyclic ring and substituted in the benzene ring with chains or rings of hydrocarbons and oxygen, principally fragment at the side chain releasing unsaturated hydrocarbons. The ESI-QTOF-MS/MS behaviour of some naturally occurring and synthetic quinolines which are structurally similar or fragment similarly are included where appropriate.

Inguinal Hernia in Premature Infants.

Inguinal hernia is a common problem affecting infants in the NICU. As a group, preterm infants have the highest incidence of inguinal hernia and this risk increases as gestational age decreases. The etiopathologic factors leading to the development of an inguinal hernia are not clear and interventions to alter these factors have not been thoroughly investigated. Diagnosis of an inguinal hernia is often straightforward, but occasionally it may be difficult to determine if the hernia is strangulated or simply obstructed. Rarely, investigative modalities, such as ultrasonography, may be needed to rule out other potential causes. The ideal timing of surgical repair in this population is unknown and complicated by comorbid conditions and limited randomized controlled trials. During surgery, the choice of regional versus general anesthesia requires a team-based approach and studies have found that greater clinical experience is associated with lower morbidity. The techniques of hernia surgery range from open to laparoscopic repair and have been investigated in small prospective studies, while larger databases have been used to analyze outcomes retrospectively.

Anterior Vertebral Body Tethering for Adolescent Scoliosis with Growth Remaining: A Retrospective Review of 2 to 5-Year Postoperative Results.

BACKGROUND: Anterior vertebral body tethering (VBT) is an early treatment option for progressive scoliosis in pediatric patients, allowing for continued deformity correction during normal growth. We report postoperative radiographic and clinical outcomes for patients treated with VBT. METHODS: This clinical and radiographic retrospective review of 31 consecutive patients included an analysis of preoperative, perioperative, and postoperative details, including the Lenke classification; Cobb angle measurements of the proximal thoracic, main thoracic, and lumbar curves; the sagittal profile; and skeletal maturity. Successful outcomes were defined by a residual curve of ≤30° in skeletally mature patients who did not undergo a posterior spinal fusion (PSF). RESULTS: Of the 31 patients treated, 29 met the inclusion criteria, and 2 were lost to follow-up. The mean patient age (and standard deviation) at the time of the surgical procedure was 12.7 ± 1.5 years (range, 10.2 to 16.7 years), with most patients classified as Risser grade 0 or 1 (52%) and Sanders stage 3 (32%). A mean of 7.2 ± 1.4 vertebral levels were instrumented, with a minimum preoperative Cobb angle of 42°. At the latest follow-up, 27 patients had reached skeletal maturity (Sanders stage ≥7) and 20 patients exhibited a curve magnitude ≤30°, for a success rate of 74%. A suspected broken tether occurred at ≥1 level in 14 patients (48%). Two patients underwent PSF and 4 had tether revision. The overall revision rate was 21% (6 of 29). CONCLUSIONS: This study shows the success and revision rates as well as the impact of a suspected broken tether on the procedural success of VBT. Despite our patient population being slightly more mature at the time of the surgical procedure compared with previous studies, we had a higher success rate and a lower revision rate. A PSF was avoided in 93% of patients, indicating that VBT may be a reliable treatment option for adolescent scoliosis in skeletally immature individuals. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Perioperative care of a child with Ullrich congenital muscular dystrophy.

Ullrich congential muscular dystrophy (UCMD) is a severe form of congenital muscular dystrophy manifesting axial muscle contractures and distal joint hyperlaxity. Severe hypotonia and associated respiratory failure may occur early in the disease process. Given the various associated orthopedic conditions, anesthetic management may be required during surgical interventions to correct skeletal deformities or these patients may present with surgical conditions unrelated to their primary illness. We present a 4-year-old with UCMD who required operative intervention for a ruptured appendix. Anesthetic care implications included the need for a rapid airway control to limit the risks of aspiration due to the intra-abdominal process, choice of neuromuscular blocking agent for rapid sequence intubation, associated airway issues related to micrognathia and limited mouth opening, and the potential for involvement of the cardiovascular and respiratory systems. The perioperative management of patients with UCMD is discussed including the use of propofol and remifentanil for rapid sequence intubation to avoid the need for neuromuscular blocking agents.

Short course induction immunosuppression with thymoglobulin for renal transplant recipients.

BACKGROUND: The aim of this study was to demonstrate that 3-days of induction immunosuppression with thymoglobulin was as effective and safe as a 7-day course and reduced initial hospitalization after transplantation. METHODS: This was a prospective, nonrandomized trial of 40 consecutive patients receiving thymoglobulin induction for 3 days and followed for 1 year. An historical group of 48 patients that received 7 days of thymoglobulin served as controls. RESULTS: At 1 year, acute rejection (5 vs. 4%), graft survival (95 vs. 98%) and patient survival were similar; a composite end point of freedom from death, rejection, or graft loss, the event-free graft survival, was similar as was the safety profile. In the 3-day group, lymphocyte depletion was more sustained and initial hospitalization was significantly shorter (6 vs. 8 days). CONCLUSION: Three-day induction with thymoglobulin is as effective and safe as seven days, decreases initial hospitalization and causes more sustained lymphocyte depletion.

Aortic hiatus gastric hernia.

Congenital diaphragmatic hernias are a relatively common anomaly that can present with significant respiratory morbidity and mortality. We report on a case of an aortic-hiatal gastric hernia that initially presented with repeated episodes of respiratory distress, which was diagnosed as asthma. The diagnosis of a diaphragmatic hernia was made at 18 months of age. In the operating room, it was noted that it was an aortic hiatal hernia, which was surgically repaired. Subsequently, there has been improvement in daily respiratory symptoms.

The characterisation of selected drugs with amine-containing side chains using electrospray ionisation and ion trap mass spectrometry and their determination by HPLC-ESI-MS.

The electrospray ionisation-ion-trap mass spectrometry (ESI-MS(n)) of selected drug compounds with amine-containing side chains has been investigated. Certain characteristic in-source fragmentations have been observed for these molecules. Sequential product ion fragmentation experiments (MS(n)) have been performed in order to elucidate the degradation pathways for the [M + H](+) ions and their predominant fragment ions. These MS(n) experiments also show certain characteristic fragmentations with respect to the amine-containing side chains. QTOF-MS/MS has been used to support the identity of the proposed fragments. The data presented in this paper therefore provides useful information on the structure of these compounds with amine-containing side chains and can be used in the characterisation of such drugs, their structurally related metabolites and unknown molecules of pharmaceutical significance extracted from animal and plant sources, for example. Amphetamine, clenbuterol, flurazepam and methadone can be identified and determined in mixtures at low ng/ml concentrations by the application of HPLC-ESI-MS which can also be used for their analysis in saliva samples.

Intraoperative diagnosis of unsuspected methemoglobinemia due to low pulse oximetry values.

Methemoglobinemia results from the oxidation of the iron in the hemoglobin molecule from the ferrous to the ferric state. Methemoglobinemia may result from congenital deficiencies of enzymes that normally convert methemoglobin (metHb) to hemoglobin, alterations in the hemoglobin molecule itself or, most commonly, from medications or toxins. As metHb cannot carry oxygen, clinical sequelae result when the concentration of metHb is high enough to compromise oxygen delivery to the tissues. With low levels, the patient may be asymptomatic or only symptomatic during periods of increased tissue oxygen demands such as exercise. With higher levels, symptoms may occur at rest. We describe an adolescent with acute leukemia who presented to the operating room for placement of a Broviac catheter for permanent central venous access. Given a persistently low oxygen saturation as measured by pulse oximetry (92% to 94%) with no response to changes in the inspired oxygen concentration and the lack of physical findings on auscultation to explain the low oxygen saturation, the diagnosis of metHb was entertained and confirmed by laboratory analysis.

Clevidipine controls intraoperative blood pressure in an adolescent with renal failure.

In pediatric-aged patients, various factors may result in perioperative hypertension including renal failure or insufficiency, volume overload, or other factors that activate the sympathetic nervous system including pain and agitation. Perioperative blood pressure control may be even more difficult to achieve and maintain in patients with pre-existing hypertension. We present a 16-year-old adolescent with renal failure and hypertension who presented for anesthetic care during placement of a peritoneal dialysis catheter. Perioperative blood pressure control was achieved with the administration of clevidipine, an ultra-short acting calcium channel antagonist of the dihydropyridine class. Its role in the perioperative control of blood pressure is discussed.

A study of the analytical behaviour of selected psycho-active drugs using liquid chromatography, ion trap mass spectrometry, gas chromatography and polarography and the construction of an appropriate database for drug characterisation.

This paper provides analytical chemical information on a range of psycho-active drugs. This analytical chemical information on liquid chromatography-electrospray ionisation-mass spectrometry (HPLC-ESI-MS), ion trap mass spectrometry (ESI-MS(n)), gas chromatography-flame ionisation detection (GLC-FID) and polarographic behaviour is then incorporated into a database which is of use in drug characterisation. Application is found in the determination of selected drug compounds in hair samples.

Characterisation of selected drugs with nitrogen-containing saturated ring structures by use of electrospray ionisation with ion-trap mass spectrometry.

The electrospray ionisation-ion-trap mass spectrometry (ESI-MS(n)) of selected drugs with nitrogen-containing saturated ring structures has been investigated. Sequential product-ion fragmentation experiments (MS(n)) have been performed to elucidate degradation pathways for the [M+H](+) ions and their predominant fragment ions. These MS(n) experiments result in characteristic fragmentations in which functional groups are generally cleaved from the ring systems as neutral molecules such as H(2)O, amines, alkenes, esters, carboxylic acids, etc. When such a nitrogen-containing drug molecule also contains a functional group, such as an ester, that on liberation as a neutral molecule has a significantly lower -Delta H(f) degrees value than that of the corresponding amine then the former is preferentially liberated. Furthermore, when an aromatic entity is present in these drug molecules together with the nitrogen-containing saturated ring structure fragmentation of the latter ring occurs with the former, predictably, being resistant to fragmentation. The structures of fragment ions proposed for ESI-MS(n) can be supported by electrospray ionisation-quadrupole time-of-flight mass spectrometry (ESI-QTOFMS). The data presented in this paper therefore provide useful information on the structure of these heterocyclic compounds which could be used to characterise unknown drug compounds isolated from natural sources, for example.