In situ detection and analysis of laser-induced damage on a 1.5-m multilayer-dielectric grating compressor for high-energy, petawatt-class laser systems

A grating-inspection system and a damage-analysis method have been developed to measure in situ laser-induced damage on a 1.5-m tiled-grating assembly of the OMEGA EP pulse compressor during a 15-ps, 2.2-kJ energy ramp. The beam fluence at which significant damage growth occurred was determined. This is the first report on beam fluence versus laser-induced-damage growth of meter-sized multilayer-dielectric-diffraction gratings. This result was correlated to the damage-probability measurement conducted on a small grating sample and is consistent with the fluence, corresponding to 100% damage probability.

The role of neural activity in the migration and differentiation of enteric neuron precursors

BACKGROUND

As they migrate through the developing gut, a sub-population of enteric neural crest-derived cells (ENCCs) begins to differentiate into neurons. The early appearance of neurons raises the possibility that electrical activity and neurotransmitter release could influence the migration or differentiation of ENNCs.

METHODS

The appearance of neuronal sub-types in the gut of embryonic mice was examined using immunohistochemistry. The effects of blocking various forms of neural activity on ENCC migration and neuronal differentiation were examined using explants of cultured embryonic gut.

KEY RESULTS

Nerve fibers were present in close apposition to many ENCCs. Commencing at E11.5, neuronal nitric oxide synthase (nNOS), calbindin and IK(Ca) channel immunoreactivities were shown by sub-populations of enteric neurons. In cultured explants of embryonic gut, tetrodotoxin (TTX, an inhibitor of action potential generation), nitro-L-arginine (NOLA, an inhibitor of nitric oxide synthesis) and clotrimazole (an IK(Ca) channel blocker) did not affect the rate of ENCC migration, but tetanus toxin (an inhibitor of SNARE-mediated vesicle fusion) significantly impaired ENCC migration as previously reported. In explants of E11.5 and E12.5 hindgut grown in the presence of TTX or tetanus toxin there was a decrease in the number nNOS+ neurons close to the migratory wavefront, but no significant difference in the proportion of all ENCC that expressed the pan-neuronal marker, Hu.

CONCLUSIONS & INFERENCES

(i) Some enteric neuron sub-types are present very early during the development of the enteric nervous system. (ii) The rate of differentiation of some sub-types of enteric neurons appears to be influenced by TTX- and tetanus toxin-sensitive mechanisms.

Patterns of recurrence in patients with acute diverticulitis

Background

The natural history of acute diverticulitis remains unclear, with the role of prophylactic surgery following conservatively managed diverticulitis increasingly controversial. This study investigated recurrence rates, patterns and complications after conservatively managed diverticulitis.

Methods

This was a retrospective chart review of all patients admitted with diverticulitis between June 1997 and June 2002. Demographic data, management, recurrence rates, complications and subsequent surgery were recorded.

Results

Some 502 patients were identified, 337 with uncomplicated and 165 with complicated diverticulitis. Median follow-up was 101 (range 60–124) months. Of 320 patients with uncomplicated diverticulitis managed conservatively, 60 (18·8 per cent) had one episode of recurrence, whereas 15 (4·7 per cent) had two or more episodes. After an initial attack of uncomplicated diverticulitis, only 5·0 per cent developed complicated disease. Complicated disease recurred in 24 per cent, compared with a recurrence rate of 23·4 per cent in those with uncomplicated diverticulitis (P = 0·622). When recurrence occurred, it usually did so within 12 months of the initial episode.

Conclusion

Acute diverticulitis has a low recurrence rate and rarely progresses to complications. Any recurrence is usually early, in a pattern more consistent with failure of the index episode to settle. Subsequent elective surgery to prevent recurrence and the development of complications should be used sparingly.

[Impact of intrathecal morphine on the tolerance of early feeding after cesarean section]

INTRODUCTION

Early feeding is well tolerated in patients undergoing caesarean section under general or regional anaesthesia. Intrathecal morphine is effective for postoperative analgesia but can induce nausea and vomiting which may hamper feeding. This study assessed prospectively the effects of intrathecal morphine on early feeding in patients undergoing caesarean section.

METHODOLOGY

After ethical committee approval, 66 consenting women scheduled for caesarean section were randomized to receive intrathecal morphine 0.1 mg (group M, n=32) or not ("control group", group C, n=34) at the time of intrathecal anaesthesia performed with a 3 ml mixture containing 8.6 mg bupivacaine, 64 microg clonidine and 4.3 microg sufentanil. Standard antiemetic prophylaxis (5 mg dexamethasone + 2 mg tropisetron) was administered intravenously in all patients after umbilical cord clamping. Standardized multimodal analgesia was initiated postoperatively with 1 g of paracetamol and 30 mg of ketorolac given every 6 hours. Analgesia was evaluated by a numeric rating scale (NRS) at 4 hours intervals and 10 mg of oral morphine was administered if the NRS score exceeded 3. All patients received a protein enriched solution, 8 hours after caesarean section and were allowed to eat solid food on postoperative day 1. Nausea and vomiting episodes, gas and/or stools emission, itching, NRS score and morphine consumption were recorded on the first, second and fourth postoperative hour and then every 4 hours during 48 hours.

RESULTS

Nausea was significantly more frequent and persisted longer in group M. Vomiting occurred equally in both groups and stopped after feeding. Gas and/or stools emission appeared within 48 hours postoperatively in 72 and 77 % of patients in group M and group C respectively. Oral morphine consumption was significantly lower in group M (1.9+/-4 vs 6.5+/-7.3mg, p=0.006). When compared to group C, NRS were also lower in group M from the second to the 20th postoperative hour. Itching was observed more frequently and persisted longer in group M.

DISCUSSION AND CONCLUSION

A small dose of intrathecal morphine provided adequate and prolonged pain relief after caesarean section but increased the incidence of nausea and vomiting despite anti-emetic prophylaxis. Oral food intake was not hampered by intrathecal morphine.

Identification of key water quality characteristics affecting the filterability of biologically treated effluent in low-pressure membrane filtration

There are many water quality characteristics which could influence the filterability of biologically treated effluent from Melbourne's Western Treatment Plant (WTP). Statistical correlation was used to identify the key water characteristics affecting the microfiltration (MF) and ultrafiltration (UF) filterability in terms of permeate volume of the treated effluent. The models developed showed that turbidity, dissolved organic carbon (DOC) and total suspended solids (TSS) were the key factors which influenced the MF and UF filterability. Turbidity was the dominant factor affecting the accuracy of the model for MF filterability while DOC was the major factor affecting the accuracy of the model for UF filterability. A prediction accuracy of 85% was obtained for MF and 86% for UF filterability of the WTP effluent. The characteristics of the organic components of the wastewater were demonstrated by EEM spectra to have seasonal variation which would have reduced the prediction accuracy. As turbidity, DOC and TSS can be determined on-line, the models would be useful for rapid prediction of the filterability of WTP effluent and this may assist the control of low-pressure membrane filtration processes.

The role of intravascular ultrasound to guide drug-eluting stents implantation

Serial IVUS has demonstrated significant differences in intimal hyperplasia (IH) volume between drug-eluting stent (DES) and bare metal stents (BMS) in recent clinical trials. It has also been reported that IVUS is a useful tool in determining optimal DES implantation, especially for diabetes mellitus (DM) patients. Recent data have also suggested a critical role for, IVUS guidance in reduction of risk for DES thrombosis. IVUS has been invaluable in the elucidation of DES effects on the arterial wall, offering insight into the potential mechanisms of DES failure. Therefore, in this current manuscript, we review the potential benefits of intravascular ultrasound (IVUS) during drug eluting stent (DES) implantation.

A high affinity pyruvate decarboxylase is present in cottonwood leaf veins and petioles: a second source of leaf acetaldehyde emission?

Considerable evidence indicates that acetaldehyde is released from the leaves of a variety of plants. The conventional explanation for this is that ethanol formed in the roots is transported to the leaves where it is converted to acetaldehyde by the alcohol dehydrogenase (ADH) found in the leaves. It is possible that acetaldehyde could also be formed in leaves by action of pyruvate decarboxylase (PDC), an enzyme with an uncertain metabolic role, which has been detected, but not characterized, in cottonwood leaves. We have found that leaf PDC is present in leaf veins and petioles, as well as in non-vein tissues. Veins and petioles contained measurable pyruvate concentrations in the range of 2mM. The leaf vein form of the enzyme was purified approximately 143-fold, and, at the optimum pH of 5.6, the K(m) value for pyruvate was 42 microM. This K(m) is lower than the typical millimolar range seen for PDCs from other sources. The purified leaf PDC also decarboxylates 2-ketobutyric acid (K(m)=2.2mM). We conclude that there are several possible sources of acetaldehyde production in cottonwood leaves: the well-characterized root-derived ethanol oxidation by ADH in leaves, and the decarboxylation of pyruvate by PDC in leaf veins, petioles, and other leaf tissues. Significantly, the leaf vein form of PDC with its high affinity for pyruvate, could function to shunt pyruvate carbon to the pyruvate dehydrogenase by-pass and thus protect the metabolically active vascular bundle cells from the effects of oxygen deprivation.

Meta-analysis and imputation identifies a 109 kb risk haplotype spanning TNFAIP3 associated with lupus nephritis and hematologic manifestations

TNFAIP3 encodes the ubiquitin-modifying enzyme, A20, a key regulator of inflammatory signaling pathways. We previously reported association between TNFAIP3 variants and systemic lupus erythematosus (SLE). To further localize the risk variant(s), we performed a meta-analysis using genetic data available from two Caucasian case-control datasets (1453 total cases, 3381 total control subjects) and 713 SLE trio families. The best result was found at rs5029939 (P=1.67 x 10(-14), odds ratio=2.09, 95% confidence interval 1.68-2.60). We then imputed single nucleotide polymorphisms (SNPs) from the CEU Phase II HapMap using genotypes from 431 SLE cases and 2155 control subjects. Imputation identified 11 SNPs in addition to three observed SNPs, which together, defined a 109 kb SLE risk segment surrounding TNFAIP3. When evaluating whether the rs5029939 risk allele was associated with SLE clinical manifestations, we observed that heterozygous carriers of the TNFAIP3 risk allele at rs5029939 have a twofold increased risk of developing renal or hematologic manifestations compared to homozygous non-risk subjects. In summary, our study strengthens the genetic evidence that variants in the region of TNFAIP3 influence risk for SLE, particularly in patients with renal and hematologic manifestations, and narrows the risk effect to a 109 kb DNA segment that spans the TNFAIP3 gene.

Fellow eye changes in optic neuritis correlate with the risk of multiple sclerosis

BACKGROUND

Recent studies demonstrate early diffuse central nervous system (CNS) inflammation in patients with multiple sclerosis (MS). The clinically unaffected (fellow) eye of patients with unilateral optic neuritis (ON) may reflect the status of normal-appearing white matter in the CNS, which can be assessed electrophysiologically.

OBJECTIVE

To study the relationship between electrophysiological parameters in the fellow eye of ON patients, and risk of conversion to MS.

METHODS

Forty-eight consecutive patients with acute unilateral ON were examined 12 months after ON of which 14 had MS, 19 remained high risk (HR) for MS, and 15 had low risk (LR) for MS according to McDonald's criteria. Twenty-five age-matched controls were also tested. Amplitude and latency of multifocal visual evoked potential (mfVEP) in the fellow eyes of patients at 12 months were analyzed and compared with controls.

RESULTS

Average mfVEP amplitude was 240 +/- 35, 232 +/- 36, 181 +/- 38, and 169 +/- 48 nV for controls, LR, HR, and MS groups respectively. Average mfVEP latency for controls, LR, HR, and MS patients was 139.7 +/- 5.5, 141.7 +/- 3.6, 145.9 +/- 8.9, and 152.0 +/- 9.9 ms respectively.

CONCLUSIONS

The magnitude of latency prolongation and amplitude decline 12 months after the initial episode was proportional to the risk of MS. The prognostic significance of these changes as predictors of subsequent MS should be investigated longitudinally.