Improved Signal Processing for Mass Shifting Ions in Charge Detection Mass Spectrometry

The quality of data in charge detection mass spectrometry depends on accurate determination of ion charge. While the method of selective temporal overview of resonant ions (STORI) has proven to be highly enabling for determining the charge of ions that survive for variable amounts of time, it assumes that the ion frequency exactly matches the frequency being used in the calculation. Any mismatches result in low charge estimates. To address this, the misSTORI method was developed to correct these discrepancies. This can significantly reduce the charge measurement errors for samples with unstable masses. As an example, the misSTORI approach can eliminate a 5.7% charge determination error for a VP3-only AAV capsid that shifts 25 ppm in mass.

Dynamic Data-Independent Acquisition Mass Spectrometry with Real-Time Retrospective Alignment

Data-independent acquisition (DIA) mass spectrometry has grown in popularity in recent years, because of the reproducibility and quantitative rigor of a systematic tandem mass spectrometry (MS/MS) sampling method. However, traditional DIA methods may spend valuable instrument time acquiring MS/MS spectra with no usable information in them, affecting sensitivity and quantitative performance. We developed a DIA strategy that dynamically adjusts the MS/MS windows during the chromatographic separation. The method focuses MS/MS acquisition on the most relevant mass range at each point in time─increasing the quantitative sensitivity by increasing the time spent on each DIA window. We demonstrate an improved lower limit of quantification, on average, without sacrificing the number of peptides detected.

Alterations in the Stool Microbiome in Newborns undergoing Mild Therapeutic Hypothermia after Hypoxic-Ischemic Encephalopathy

BACKGROUND

Hypoxic-ischemic encephalopathy (HIE) is associated with brain injury in newborns, and may lead to disability or death. Mild therapeutic hypothermia (TH) is an effective neuroprotective intervention and an established standard of care in western countries. The gut microbiome, the genomic and physico-chemical contribution of the gut microbiota, serves important functions and is increasingly recognised as a major influencer on development. The impact of HIE and TH on the evolving gut microbiota of the newborn remains to be elucidated.

OBJECTIVE

To carry out an exploratory study on the effects of HIE and TH on the gut microbiome in term neonates.

METHODS AND RESULTS

Stool samples were obtained from 28 newborns with HIE (median age 68 h) undergoing TH on the neonatal unit (HIE TH group), with a follow-on stool sample available for 20 of these babies (median age 151 h). For comparison, a single stool specimen was obtained from 19 healthy newborns on the postnatal ward (median age 34 h). The microbiota composition was determined using established microbial DNA extraction and 16S rRNA gene sequencing methodology. There was no difference in the mode of delivery or the method of feeding the newborns, once established, between the two groups. All the infants in the HIE TH group had received antibiotics compared to only one of the controls. A lower -diversity, quantified by the Shannon diversity index, was noted in the microbiota of the HIE TH group in comparison to the control group. The HIE TH group had a higher mean relative abundance (MRA) of facultative anaerobes and aerobes such as Staphylococcus species and a lower MRA of strict anaerobes, such as members of the Bacteroides genus, compared to the control. Also, there was a significant reduction in the MRA of the genus Bifidobacterium in the HIE TH group. Although the mode of delivery exerts a profound influence on the gut microbiota of the newborn, distance-based redundancy analysis showed that TH may exert an independent influence. This study could not determine the independent contribution of the use of antibiotics or the NICU environment.

CONCLUSION

In this study we demonstrate an alteration in the microbiota composition in newborns undergoing TH for HIE. (359 words).

Highly Multiplex Targeted Proteomics Enabled by Real-Time Chromatographic Alignment

Targeted mass spectrometry methods produce high-quality quantitative data in terms of limits of detection and dynamic range, at the cost of a substantial compromise in throughput compared to methods such as data independent and data dependent acquisition. The logistical and experimental issues inherent to maintaining assays of even several hundred targets are significant. Prominent among these issues is the drift in analyte retention time as liquid chromatography (LC) columns wear, forcing targeted scheduling windows to be much larger than LC peak widths. If these problems could be solved, proteomics assays would be capable of targeting thousands of peptides in an hour-long experiment, enabling large cohort studies to be performed without sacrificing sensitivity and specificity. We describe a solution in the form of a new method for real-time chromatographic alignment and demonstrate its application to a 56 min LC-gradient HeLa digest assay with 1489 targets. The method is based on the periodic acquisition of untargeted survey scans in a reference experiment and alignment to those scans during subsequent experiments. We describe how the method enables narrower scheduled retention time windows to be used. The narrower scheduling windows enables more targets to be included in the assay or proportionally more time to be allocated to each target, improving the sensitivity. Finally, we point out how the procedure could be improved and how much additional target multiplexing could be gained in the future.

JUNO, the receptor of sperm IZUMO1, is expressed by the human oocyte and is essential for human fertilisation

STUDY QUESTION

Is JUNO protein present at the surface membrane of human oocytes and involved in the fertilisation process?

SUMMARY ANSWER

JUNO protein is expressed on the plasma membrane of human oocytes and its inhibition by a monoclonal antibody completely blocks gamete fusion.

WHAT IS KNOWN ALREADY

Fusion of gamete membranes is the culminating event of the fertilisation process, but its molecular mechanisms are poorly understood. Until now, three molecules have been shown to be essential: CD9 tetraspanin in the oocyte, Izumo1 protein on the sperm and Juno, its corresponding receptor on the oocyte. Oocyte CD9 and sperm IZUMO1 have been identified in human gametes and their interaction is also well-conserved among several mammalian species. The presence of JUNO on human oocytes, however, has not yet been reported, nor has its role in fertilisation been investigated.

STUDY DESIGN, SIZE, DURATION

We selected an anti-human JUNO antibody in order to investigate the presence of JUNO on the oocyte membrane surface and studied its potential involvement in gamete membrane interaction during fertilisation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Monoclonal antibodies against human JUNO (anti-hJUNO mAb) were produced by immunisation of mice with HEK cells transfected with the putative human JUNO sequence (HEK-hJUNO). These antibodies were used for immunostaining experiments and in vitro fertilisation assays with human gametes (GERMETHEQUE Biobank).

MAIN RESULTS AND THE ROLE OF CHANCE

Three hybridoma supernatants, verified by immunostaining, revealed specifically HEK-hJUNO cells. The three purified monoclonal antibodies, FJ2E4 (IgG1), FJ8E8 (IgG1) and FJ4F5 (IgG2a), recognised the soluble recombinant human JUNO protein and, in a western blot of HEK-hJUNO extracts, a protein with an expected MW of 25 kDa. In addition, soluble recombinant human IZUMO protein inhibited the binding of anti-hJUNO mAbs to cells expressing hJUNO. Using these anti-hJUNO mAbs in immunostaining, we identified the presence of JUNO protein at the plasma membrane of human oocytes. Furthermore, we revealed a progressive expression of JUNO according to oocyte maturity. Finally, we showed that human zona-free oocytes, inseminated in the presence of anti-hJUNO mAb, were not fertilised by human sperm. These results suggest that, as seen in the mouse, JUNO is indeed involved in human gamete membrane fusion during fertilisation.

LARGE-SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

In accordance with French bioethics laws, functional tests were performed using zona-free oocytes, which of course does not fully encompass all normal in vivo physiological conditions. However, these in vitro tests do provide direct information regarding sperm-oocyte membrane interactions.

WIDER IMPLICATIONS OF THE FINDINGS

Mechanisms of gamete fusion appear to be homologous between mice and humans. However, some differences do exist and analysing the human mechanisms is essential. In fact, this is the first report describing the presence of JUNO on human oocytes and its involvement in human fertilisation. This discovery allows further examination of the understanding of molecular mechanisms that drive gamete fusion: a crucial challenge at a time when infertility affects 16% of reproductively active couples.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the Agence Nationale pour la Recherche, Grant no. ANR-13-BVS5-0004, and by Association Institut du Cancer et d'Immunogénétique (ICIG). There are no competing interests.

Comparison of Forced-air Warming and Radiant Heating during Transurethral Prostatic Resection under Spinal Anaesthesia

Forced-air warming is commonly used to warm patients intraoperatively, but may not achieve normothermia during a short procedure. Comparative trials of a new radiant warming device in general anaesthesia (Suntouch™, Fisher and Paykel, Auckland, New Zealand) have had conflicting results. We conducted a randomized controlled trial to compare the efficacy and thermal comfort of the Suntouch™ radiant warmer and forced-air warming in patients at high risk of hypothermia during neuraxial blockade. With ethics committee approval, 60 patients having transurethral resection of the prostate under spinal were randomized to either radiant warming or forced-air warming. All intravenous and irrigation fluids were warmed but pre-warming was not used. The final intraoperative rectal temperatures for the radiant warming and forced-air warming groups were 36.1°C and 36.4°C respectively (P=0.03). A large proportion of patients in both groups (46% and 33% respectively, P=0.3) were hypothermic (<36°C) on arrival in the post-anaesthesia care unit. No other patient variables were significantly different. Neither warming device reliably prevented hypothermia, although forced-air warming was slightly superior.

Tissue-enhanced plasma proteomic analysis for disease stratification in amyotrophic lateral sclerosis

Background

It is unclear to what extent pre-clinical studies in genetically homogeneous animal models of amyotrophic lateral sclerosis (ALS), an invariably fatal neurodegenerative disorder, can be informative of human pathology. The disease modifying effects in animal models of most therapeutic compounds have not been reproduced in patients. To advance therapeutics in ALS, we need easily accessible disease biomarkers which can discriminate across the phenotypic variants observed in ALS patients and can bridge animal and human pathology. Peripheral blood mononuclear cells alterations reflect the rate of progression of the disease representing an ideal biological substrate for biomarkers discovery.

Methods

We have applied TMTcalibrator™, a novel tissue-enhanced bio fluid mass spectrometry technique, to study the plasma proteome in ALS, using peripheral blood mononuclear cells as tissue calibrator. We have tested slow and fast progressing SOD1G93A mouse models of ALS at a pre-symptomatic and symptomatic stage in parallel with fast and slow progressing ALS patients at an early and late stage of the disease. Immunoassays were used to retest the expression of relevant protein candidates.

Results

The biological features differentiating fast from slow progressing mouse model plasma proteomes were different from those identified in human pathology, with only processes encompassing membrane trafficking with translocation of GLUT4, innate immunity, acute phase response and cytoskeleton organization showing enrichment in both species. Biological processes associated with senescence, RNA processing, cell stress and metabolism, major histocompatibility complex-II linked immune-reactivity and apoptosis (early stage) were enriched specifically in fast progressing ALS patients. Immunodetection confirmed regulation of the immunosenescence markers Galectin-3, Integrin beta 3 and Transforming growth factor beta-1 in plasma from pre-symptomatic and symptomatic transgenic animals while Apolipoprotein E differential plasma expression provided a good separation between fast and slow progressing ALS patients.

Conclusions

These findings implicate immunosenescence and metabolism as novel targets for biomarkers and therapeutic discovery and suggest immunomodulation as an early intervention. The variance observed in the plasma proteomes may depend on different biological patterns of disease progression in human and animal model.

Electronic supplementary material

The online version of this article (10.1186/s13024-018-0292-2) contains supplementary material, which is available to authorized users.

Pre-operative anaemia, intra-operative hepcidin concentration and acute kidney injury after cardiac surgery: a retrospective observational study

Acute kidney after cardiac surgery is more common in anaemic patients, whereas haemolysis during cardiopulmonary bypass may lead to iron-induced renal injury. Hepcidin promotes iron sequestration by macrophages: hepcidin concentration is reduced by anaemia and increased by inflammation. We analysed the associations in 525 patients between pre-operative anaemia (haemoglobin < 130 g.l^-1 in men and < 120 g.l^-1 in women), intra-operative hepcidin concentration and acute kidney injury (dialysis or > 26.4 μmol.l^-1 or > 50% creatinine increase during the first two days after cardiac surgery. Rates of pre-operative anaemia and postoperative kidney injury were 109/525 (21%) and 36/525 (7%), respectively. The median (IQR [range]) intra-operative hepcidin concentration was 20 (10-33 [0-125]) μg.l^-1 and was lower in anaemic patients than those who were not: 15 (4-28 [0-125]) μg.l^-1 vs. 21 (12-33 [0-125]) μg.l^-1 , respectively, p = 0.002. Four variables were independently associated with postoperative kidney injury, for which the beta-coefficients (SE) were: minutes on cardiopulmonary bypass, 0.016 (0.004), p < 0.001; intra-operative hepcidin concentration, 0.032 (0.008), p < 0.001; pre-operative anaemia, 1.97 (0.56), p < 0.001; and Cleveland clinic risk score, 0.88 (0.35), p = 0.005. Contrary to generally increased rates of kidney injury in patients with higher hepcidin concentrations, rates of kidney injury in anaemic patients were lower in patients with higher hepcidin concentrations, beta-coefficient (SE) -0.037 (0.01), p = 0.007. In cardiac surgical patients the rate of postoperative acute kidney injury predicted by the Cleveland risk score might be adjusted for pre-operative anaemia and intra-operative cardiopulmonary bypass time and hepcidin concentration. Pre-operative correction of anaemia, reduction in intra-operative bypass time and modification of iron homeostasis and hepcidin concentration might reduce acute kidney injury.

Normothermic Ex Vivo Kidney Perfusion Following Static Cold Storage-Brief, Intermediate, or Prolonged Perfusion for Optimal Renal Graft Reconditioning?

Normothermic ex vivo kidney perfusion (NEVKP) demonstrated superior results compared to hypothermic storage in donation after circulatory death (DCD) kidney transplantation. It is unknown whether an optimal perfusion time exists following hypothermic storage to allow for the recovery of renal grafts from cold ischemic injury. In a porcine model of DCD kidney autotransplantation, the impact of initial static cold storage (SCS) (8 h) followed by various periods of NEVKP recovery was investigated: group A, 8 hSCS only (control); group B, 8 hSCS + 1 hNEVKP (brief NEVKP); group C, 8 hSCS + 8 hNEVKP (intermediate NEVKP); and group D, 8 hSCS + 16 hNEVKP (prolonged NEVKP). All grafts were preserved and transplanted successfully. One animal in group D was sacrificed and excluded by postoperative day 3 due to hind limb paralysis, but demonstrated good renal function. Postoperative graft assessment during 8 days' follow-up demonstrated lowest levels of peak serum creatinine for intermediate (C) and prolonged (D) NEVKP (p = 0.027). Histological assessment on day 8 demonstrated a significant difference in tubular injury (p = 0.001), with highest values for group B. These results suggest that longer periods of NEVKP following SCS are feasible and safe for postponing surgical transplant procedure and superior to brief NEVKP, reducing the damage caused during cold ischemic storage of renal grafts.

Continuous Normothermic Ex Vivo Kidney Perfusion Is Superior to Brief Normothermic Perfusion Following Static Cold Storage in Donation After Circulatory Death Pig Kidney Transplantation

Hypothermic preservation is known to cause renal graft injury, especially in donation after circulatory death (DCD) kidney transplantation. We investigated the impact of cold storage (SCS) versus short periods of normothermic ex vivo kidney perfusion (NEVKP) after SCS versus prolonged, continuous NEVKP with near avoidance of SCS on kidney function after transplantation. Following 30 min of warm ischemia, kidneys were removed from 30-kg Yorkshire pigs and preserved for 16 h with (A) 16 h SCS, (B) 15 h SCS + 1 h NEVKP, (C) 8 h SCS + 8 h NEVKP, and (D) 16 h NEVKP. After contralateral kidney resection, grafts were autotransplanted and pigs followed up for 8 days. Perfusate injury markers such as aspartate aminotransferase and lactate dehydrogenase remained low; lactate decreased significantly until end of perfusion in groups C and D (p < 0.001 and p = 0.002). Grafts in group D demonstrated significantly lower serum creatinine peak when compared to all other groups (p < 0.001) and 24-h creatinine clearance at day 3 after surgery was significantly higher (63.4 ± 19.0 mL/min) versus all other groups (p < 0.001). Histological assessment on day 8 demonstrated fewer apoptotic cells in group D (p = 0.008). In conclusion, prolonged, continuous NEVKP provides superior short-term outcomes following DCD kidney transplantation versus SCS or short additional NEVKP following SCS.

Interaction of fluorescent dyes with DNA and spermine using fluorescence spectroscopy

Oligonucleotides labelled with fluorescent dyes are widely used as probes for the identification of DNA sequences in detection methods using optical spectroscopies such as fluorescence and surface enhanced Raman scattering (SERS). Spermine is widely used in surface enhanced based assays as a charge reduction and aggregating agent as it interacts strongly with the phosphate backbone and has shown to enhance the signal of a labelled oligonucleotide. The fluorescence intensity of two commonly used labels, FAM and TAMRA, were compared when spermine was added under different experimental conditions. There was a marked difference upon conjugating the free dye to an oligonucleotide, when FAM was conjugated to an oligonucleotide there was around a six fold decrease in emission, compared to a six fold increase when TAMRA was conjugated to an oligonucleotide. Dye labelled single and double stranded DNA also behaved differently with double stranded DNA labelled with FAM being a much more efficient emitter in the mid pH range, however TAMRA becomes increasingly less efficient as the pH rises. Upon addition of the base spermine, signal enhancement from the FAM labelled oligonucleotide is observed. Increasing probe concentrations of TAMRA oligonucleotide above 0.5 μM led to signal reduction most likely through quenching, either by an interaction with guanine, or through self-quenching. By using different bases for comparison, spermine and triethylamine (TEA), different affects were observed in the measured fluorescence signals. When TEA was added to FAM, a reduction in the pH dependence of fluorescence was observed, which may be useful for mid pH range assays. With the drive to increase information content and decrease time and complexity of DNA assays it is likely that more assays will be carried out in complex media such as extracted DNA fragments and PCR product. This model study indicates that dye DNA and dye spermine interactions are dye specific and that extreme care with conditions is necessary particularly if it is intended to determine the concentrations of multiple analytes using probes labelled with different dyes.

Glomerular haemodynamic profile of patients with Type 1 diabetes compared with healthy control subjects

AIMS

To evaluate the glomerular haemodynamic profile of patients with Type 1 diabetes with either renal hyperfiltration (GFR ≥ 135 ml/min/1.73 m2 ) or renal normofiltration (GFR 90-134 ml/min/1.73 m2 ) during euglycaemic and hyperglycaemic conditions, and to compare this profile with that of a similar group of healthy control subjects.

METHODS

Gomez's equations were used to derive afferent and efferent arteriolar resistances, glomerular hydrostatic pressure and filtration pressure.

RESULTS

At baseline, during clamped euglycaemia, patients with Type 1 diabetes and hyperfiltration had lower mean ± sd afferent arteriolar resistance than both those with Type 1 diabetes and normofiltration (914 ± 494 vs. 2065 ± 597 dyne/s/cm5 ; P < 0.001) and healthy control subjects (1676 ± 707 dyne/s/cm(5) ; p < 0.001). By contrast, efferent arteriolar resistance was similar in the three groups. Patients with Type 1 diabetes and hyperfiltration also had higher mean ± sd glomerular hydrostatic pressure than both healthy control subjects and patients with Type 1 diabetes and normofiltration (66 ± 6 vs. 60 ± 3 vs. 55 ± 3 mmHg; P < 0.05). Similar findings for afferent arteriolar resistance, efferent arteriolar resistance, glomerular hydrostatic pressure and filtration pressure were observed during clamped hyperglycaemia.

CONCLUSION

Hyperfiltration in Type 1 diabetes is primarily driven by alterations in afferent arteriolar resistance rather than efferent arteriolar resistance. Renal protective therapies should focus on afferent renal arteriolar mechanisms through the use of pharmacological agents that target tubuloglomerular feedback, including sodium-glucose cotransporter 2 inhibitors and incretins.

High Quality Hydrothermal ZnO Crystals

Zinc Oxide crystals have historically been grown in hydrothermal autoclaves with a basic mineralizer; however, doubts have been raised about the quality of such crystals because they have often exhibited large x-ray rocking curve widths and low photoluminescence (PL) yield with large linewidths. Several ZnO crystals were grown hydrothermally and sliced parallel to the c-plane. This resulted in opposite surfaces (the C+ and C−) exhibiting pronounced chemical and mechanical differences. Different surface treatments were investigated and compared by PL both at room temperature and liquid helium temperatures, and by double axis X-ray rocking curve measurements. The high quality of hydrothermally-grown ZnO is substantiated by the narrow rocking curve widths and sharp PL peaks obtained. A critical factor in obtaining these results was found to be surface preparation.

Docosahexaenoic acid attenuates the early inflammatory response following spinal cord injury in mice: in-vivo and in-vitro studies

Background

Two families of polyunsaturated fatty acid (PUFA), omega-3 (ω-3) and omega-6 (ω-6), are required for physiological functions. The long chain ω-3 PUFAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have significant biological effects. In particular, DHA is a major component of cell membranes in the brain. It is also involved in neurotransmission. Spinal cord injury (SCI) is a highly devastating pathology that can lead to catastrophic dysfunction, with a significant reduction in the quality of life. Previous studies have shown that EPA and DHA can exert neuroprotective effects in SCI in mice and rats. The aim of this study was to analyze the mechanism of action of ω-3 PUFAs, such as DHA, in a mouse model of SCI, with a focus on the early pathophysiological processes.

Methods

In this study, SCI was induced in mice by the application of an aneurysm clip onto the dura mater via a four-level T5 to T8 laminectomy. Thirty minutes after compression, animals received a tail vein injection of DHA at a dose of 250 nmol/kg. All animals were killed at 24 h after SCI, to evaluate various parameters implicated in the spread of the injury.

Results

Our results in this in-vivo study clearly demonstrate that DHA treatment reduces key factors associated with spinal cord trauma. Treatment with DHA significantly reduced: (1) the degree of spinal cord inflammation and tissue injury, (2) pro-inflammatory cytokine expression (TNF-α), (3) nitrotyrosine formation, (4) glial fibrillary acidic protein (GFAP) expression, and (5) apoptosis (Fas-L, Bax, and Bcl-2 expression). Moreover, DHA significantly improved the recovery of limb function.

Furthermore, in this study we evaluated the effect of oxidative stress on dorsal root ganglion (DRG) cells using a well-characterized in-vitro model. Treatment with DHA ameliorated the effects of oxidative stress on neurite length and branching.

Conclusions

Our results, in vivo and in vitro, clearly demonstrate that DHA treatment reduces the development of inflammation and tissue injury associated with spinal cord trauma.

Comprehensive serum profiling for the discovery of epithelial ovarian cancer biomarkers

FDA-cleared ovarian cancer biomarkers are limited to CA-125 and HE4 for monitoring and recurrence and OVA1, a multivariate panel consisting of CA-125 and four additional biomarkers, for referring patients to a specialist. Due to relatively poor performance of these tests, more accurate and broadly applicable biomarkers are needed. We evaluated the dysregulation of 259 candidate cancer markers in serum samples from 499 patients. Sera were collected prospectively at 11 monitored sites under a single well-defined protocol. All stages of ovarian cancer and common benign gynecological conditions were represented. To ensure consistency and comparability of biomarker comparisons, all measurements were performed on a single platform, at a single site, using a panel of rigorously calibrated, qualified, high-throughput, multiplexed immunoassays and all analyses were conducted using the same software. Each marker was evaluated independently for its ability to differentiate ovarian cancer from benign conditions. A total of 175 markers were dysregulated in the cancer samples. HE4 (AUC = 0.933) and CA-125 (AUC = 0.907) were the most informative biomarkers, followed by IL-2 receptor α, α1-antitrypsin, C-reactive protein, YKL-40, cellular fibronectin, CA-72-4 and prostasin (AUC>0.800). To improve the discrimination between cancer and benign conditions, a simple multivariate combination of markers was explored using logistic regression. When combined into a single panel, the nine most informative individual biomarkers yielded an AUC value of 0.950, significantly higher than obtained when combining the markers in the OVA1 panel (AUC 0.912). Additionally, at a threshold sensitivity of 90%, the combination of the top 9 markers gave 88.9% specificity compared to 63.4% specificity for the OVA1 markers. Although a blinded validation study has not yet been performed, these results indicate that alternative biomarker combinations might lead to significant improvements in the detection of ovarian cancer.

The COX-2 inhibitors, meloxicam and nimesulide, suppress neurogenesis in the adult mouse brain

BACKGROUND AND PURPOSE

In adults, neurogenesis persists in the hippocampus and the subventricular zone (SVZ), and this is important for learning and memory. Inhibitors of COX-2 suppress ischaemia-induced neurogenesis in the hippocampus. Here, we have determined the effects of COX-2 inhibitors on neurogenesis throughout the normal adult mouse brain.

EXPERIMENTAL APPROACH

Young adult mice were treated with COX-2 inhibitors, and the proliferation of neural progenitor cells was measured in the SVZ and hippocampus. In addition, the local uptake of lentiviral vectors in the rostral migratory stream enabled the formation of new neurons in the olfactory bulb (OB) to be assessed.

KEY RESULTS

The COX-2 inhibitor meloxicam suppressed progenitor cell proliferation in the SVZ and hippocampus. A significant decrease in the appearance of new neurons in the OB was also observed. Similar effects on progenitor proliferation in the SVZ were seen with nimesulide. The absence of COX-2 expression in the proliferating progenitors in vivo, and the lack of effect of the COX-2 inhibitors on the growth rate of a cultured progenitor cell line, suggest that the effect is indirect. The specific expression of COX-2 in resting microglia that closely associate with the proliferating progenitor cells provides for a possible site of action.

CONCLUSIONS AND IMPLICATIONS

Treatment with a COX-2 inhibitor results in a substantial inhibition of adult neurogenesis. Studies on human tissues are warranted in order to determine if this effect extends to humans, and whether inhibition of neurogenesis should be considered as an adverse effect of these drugs.

Sustained sensorimotor impairments after endothelin-1 induced focal cerebral ischemia (stroke) in aged rats

Despite recent advances, stroke remains a leading cause of neurological disability with the vast majority of victims being the elderly, who exhibit more severe neurological deficits and a reduced capacity to recover from these disabilities in comparison to young stroke survivors. The objective of the present study was to develop a model of focal ischemic stroke in aged rats using endothelin-1 (ET-1) to produce low mortality rates as well as reliable, robust sensorimotor deficits that resemble functional impairments associated with stroke in humans. Here, we studied the functional and histological outcome following unilateral ET-1 infusions into the sensorimotor cortex of aged rats (20-23 months old). This procedure resulted in low mortality rates (13.3%) and no loss in body weight one week following surgery. Functional assessment was performed using a number of reliable behavioural tests: staircase test (fine motor function), horizontal ladder (skilled locomotion), bilateral tactile stimulation test (somatosensory function) and cylinder test (postural weight support). Following ET-1 induced stroke, all tests demonstrated large and sustained sensorimotor deficits in both forelimb and hindlimb function that failed to improve over the 28-day testing period. In addition, histological assessment revealed a substantial loss of retrogradely labelled corticospinal neurons in the ipsilesional hemisphere following stroke. Our results establish a model for the use of aged rats in future preclinical studies, which will enhance assessment of the long-term benefit of potential neural repair and regenerative strategies.

A retinoic acid receptor beta agonist (CD2019) overcomes inhibition of axonal outgrowth via phosphoinositide 3-kinase signalling in the injured adult spinal cord

After spinal cord injury in the adult mammal, axons do not normally regrow and this commonly leads to paralysis. Retinoic acid (RA) can stimulate neurite outgrowth in vitro of both the embryonic central and peripheral nervous system, via activation of the retinoic acid receptor (RAR) β2. We show here that regions of the adult CNS, including the cerebellum and cerebral cortex, express RARβ2. We show that when cerebellar neurons are grown in the presence of myelin-associated glycoprotein (MAG) which inhibits neurite outgrowth, RARβ can be activated in a dose dependent manner by a RARβ agonist (CD2019) and neurite outgrowth can occur via phosphoinositide 3-kinase (PI3K) signalling. In a model of spinal cord injury CD2019 also acts through PI3K signalling to induce axonal outgrowth of descending corticospinal fibres and promote functional recovery. Our data suggest that RARβ agonists may be of therapeutic potential for human spinal cord injuries.

Neural progenitors promote axon growth in vitro and ex vivo but not following injury

Following an injury to the dorsal roots primary sensory afferents fail to regenerate past the hostile dorsal root entry zone (DREZ), the interface between the peripheral and central nervous system. Neural progenitor cells have previously been utilised as a cellular replacement therapy in a variety of CNS injury models. Here we show for the first time that NPCs are capable of promoting neurite outgrowth from adult sensory neurons in vitro and ex vivo cryo-cultures. The effectiveness of NPCs as a potential means of promoting regeneration of primary afferents across the DREZ was assessed following rhizotomy at the cervical level in the adult rat. Adult rats were subjected to rhizotomy of the dorsal roots between C(5)-T(1) which were then reanastamosed. In conjunction with the rhizotomy NPCs were delivered at the DREZ. NPCs survived transplantation and were observed to differentiate predominantly into glia. Regeneration of the dorsal root fibers was assessed with immunhistochemical analysis of the large and small diameter peptidergic and non-peptidergic afferents. Although afferents appeared near to the DREZ there was little regeneration beyond the DREZ. Furthermore, no significant improvement was observed in behavioural tasks.

Multianalyte Profiling of Serum Antigens and Autoimmune and Infectious Disease Molecules to Identify Biomarkers Dysregulated in Epithelial Ovarian Cancer

Ovarian cancer is the deadliest gynecologic cancer in the United States. When detected early, the 5-year survival rate is 92%, although most cases remain undetected until the late stages where 5-year survival rates are 30%. Serum biomarkers may hold promise. Although many markers have been proposed and multivariate diagnostic models were built to fit the data on small, disparate sample sets, there has been no systematic evaluation of these markers on a single, large, well-defined sample set. To address this, we evaluated the dysregulation of 204 molecules in a sample set consisting of serum from 294 patients, collected from multiple collection sites, under a well-defined Gynecologic Oncology Group protocol. The population, weighted with early-stage cancers to assess biomarker value for early detection, contained all stages of ovarian cancer and common benign gynecologic conditions. The panel of serum molecules was assayed using rigorously qualified, high-throughput, multiplexed immunoassays and evaluated for their independent ovarian cancer diagnostic potential. Seventy-seven biomarkers were dysregulated in the ovarian cancer samples, although cancer antigen 125, C-reactive protein, epidermal growth factor receptor, interleukin 10, interleukin 8, connective tissue growth factor, haptoglobin, and tissue inhibitor of metalloproteinase 1 stood out as the most informative. When analyzed by cancer subtype and stage, there were differences in the relative value of biomarkers. In this study, using a large sample cohort, we show that some of the reported ovarian cancer biomarkers are more robust than others, and we identify additional informative candidates. These findings may guide the development of multivariate diagnostic models, which should be tested on additional, prospectively collected samples. (Cancer Epidemiol Biomarkers Prev 2008;17(10):2872–81)

A diacylglycerol lipase-CB2 cannabinoid pathway regulates adult subventricular zone neurogenesis in an age-dependent manner

The subventricular zone (SVZ) is a major site of neurogenesis in the adult. We now show that ependymal and proliferating cells in the adult mouse SVZ express diacylglycerol lipases (DAGLs), enzymes that synthesise a CB1/CB2 cannabinoid receptor ligand. DAGL and CB2 antagonists inhibit the proliferation of cultured neural stem cells, and the proliferation of progenitor cells in young animals. Furthermore, CB2 agonists stimulate progenitor cell proliferation in vivo, with this effect being more pronounced in older animals. A similar response was seen with a fatty acid amide hydrolase (FAAH) inhibitor that limits degradation of endocannabinoids. The effects on proliferation were mirrored in changes in the number of neuroblasts migrating from the SVZ to the olfactory bulb (OB). In this context, CB2 antagonists reduced the number of newborn neurons appearing in the OB in the young adult animals while CB2 agonists stimulated this in older animals. These data identify CB2 receptor agonists and FAAH inhibitors as agents that can counteract the naturally observed decline in adult neurogenesis that is associated with ageing.

Capture compound mass spectrometry: a technology for the investigation of small molecule protein interactions

One of the major hurdles in the post-genomic era is to understand the function of genes and the interplay of many different cellular proteins. This is especially important for drug development. Capture compound mass spectrometry (CCMS) addresses this challenge by selectively reducing the complexity of the proteome. Capture compounds are trifunctional molecules: a selectivity function reversibly interacts via affinity with proteins; a reactivity function irreversibly forms a covalent bond outside the affinity binding site; and a sorting/pullout function allows the captured protein(s) to be isolated from cellular lysate for mass spectrometric analysis and characterization by database queries. In the present study, we demonstrate the use of a CCMS capture compound with a sulfonamide drug analog as its selectivity function, isolating an expected target protein from cell lysates containing a large excess of other "non-target" proteins. A future application of CCMS is to define or confirm drug target proteins and their mechanisms of drug action, or to discover off-target proteins that cause side effects, enabling subsequent drug structure optimization.

Chondroitinase ABC promotes sprouting of intact and injured spinal systems after spinal cord injury

Chondroitin sulfate proteoglycans (CSPGs) are inhibitory extracellular matrix molecules that are upregulated after CNS injury. Degradation of CSPGs using the enzyme chondroitinase ABC (ChABC) can promote functional recovery after spinal cord injury. However, the mechanisms underlying this recovery are not clear. Here we investigated the effects of ChABC treatment on promoting plasticity within the spinal cord. We found robust sprouting of both injured (corticospinal) and intact (serotonergic) descending projections as well as uninjured primary afferents after a cervical dorsal column injury and ChABC treatment. Sprouting fibers were observed in aberrant locations in degenerating white matter proximal to the injury in regions where CSPGs had been degraded. Corticospinal and serotonergic sprouting fibers were also observed in spinal gray matter at and below the level of the lesion, indicating increased innervation in the terminal regions of descending projections important for locomotion. Spinal-injured animals treated with a vehicle solution showed no significant sprouting. Interestingly, ChABC treatment in uninjured animals did not induce sprouting in any system. Thus, both denervation and CSPG degradation were required to promote sprouting within the spinal cord. We also examined potential detrimental effects of ChABC-induced plasticity. However, although primary afferent sprouting was observed after lumbar dorsal column lesions and ChABC treatment, there was no increased connectivity of nociceptive neurons or development of mechanical allodynia or thermal hyperalgesia. Thus, CSPG digestion promotes robust sprouting of spinal projections in degenerating and denervated areas of the spinal cord; compensatory sprouting of descending systems could be a key mechanism underlying functional recovery.

Novel technology for rapid species-specific detection of Bacillus spores

There is an urgent need for a small, inexpensive sensor that can rapidly detect bio-warfare agents with high specificity. Bacillus anthracis, the causative agent of anthrax, would be a perilous disease-causing organism in the event of a release. Currently, most anthrax detection research is based on nucleic acid detection, immunoassays and mass spectrometry, with few detection levels reported below 10(5) spores. Here, we show the ability to distinguish Bacillus spores to a level approaching 10(3) spores, below the reported median infectious dose of B. anthracis, using pyrolysis--micromachined differential mobility spectrometry and novel pattern recognition algorithms that combine lead cluster mapping with genetic algorithms.

P2X2 knockout mice and P2X2/P2X3 double knockout mice reveal a role for the P2X2 receptor subunit in mediating multiple sensory effects of ATP

Extracellular ATP plays a role in nociceptive signalling and sensory regulation of visceral function through ionotropic receptors variably composed of P2X2 and P2X3 subunits. P2X2 and P2X3 subunits can form homomultimeric P2X2, homomultimeric P2X3, or heteromultimeric P2X2/3 receptors. However, the relative contribution of these receptor subtypes to afferent functions of ATP in vivo is poorly understood. Here we describe null mutant mice lacking the P2X2 receptor subunit (P2X2-/-) and double mutant mice lacking both P2X2 and P2X3 subunits (P2X2/P2X3(Dbl-/-)), and compare these with previously characterized P2X3-/- mice. In patch-clamp studies, nodose, coeliac and superior cervical ganglia (SCG) neurones from wild-type mice responded to ATP with sustained inward currents, while dorsal root ganglia (DRG) neurones gave predominantly transient currents. Sensory neurones from P2X2-/- mice responded to ATP with only transient inward currents, while sympathetic neurones had barely detectable responses. Neurones from P2X2/P2X3(Dbl-/-) mice had minimal to no response to ATP. These data indicate that P2X receptors on sensory and sympathetic ganglion neurones involve almost exclusively P2X2 and P2X3 subunits. P2X2-/- and P2X2/P2X3(Dbl-/-) mice had reduced pain-related behaviours in response to intraplantar injection of formalin. Significantly, P2X3-/-, P2X2-/-, and P2X2/P2X3(Dbl-/-) mice had reduced urinary bladder reflexes and decreased pelvic afferent nerve activity in response to bladder distension. No deficits in a wide variety of CNS behavioural tests were observed in P2X2-/- mice. Taken together, these data extend our findings for P2X3-/- mice, and reveal an important contribution of heteromeric P2X2/3 receptors to nociceptive responses and mechanosensory transduction within the urinary bladder.

Species-Specific Bacteria Identification Using Differential Mobility Spectrometry and Bioinformatics Pattern Recognition

As bacteria grow and proliferate, they release a variety of volatile compounds that can be profiled and used for speciation, providing an approach amenable to disease diagnosis through quick analysis of clinical cultures as well as patient breath analysis. As a practical alternative to mass spectrometry detection and whole cell pyrolysis approaches, we have developed methodology that involves detection via a sensitive, micromachined differential mobility spectrometer (microDMx), for sampling headspace gases produced by bacteria growing in liquid culture. We have applied pattern discovery/recognition algorithms (ProteomeQuest) to analyze headspace gas spectra generated by microDMx to reliably discern multiple species of bacteria in vitro: Escherichia coli, Bacillus subtilis, Bacillus thuringiensis, and Mycobacterium smegmatis. The overall accuracy for identifying volatile profiles of a species within the 95% confidence interval for the two highest accuracy models evolved was between 70.4 and 89.3% based upon the coordinated expression of between 5 and 11 features. These encouraging in vitro results suggest that the microDMx technology, coupled with bioinformatics data analysis, has potential for diagnosis of bacterial infections.

Mechanisms for intragenic complementation at the human argininosuccinate lyase locus

Argininosuccinate lyase (ASL) is a homotetrameric enzyme that catalyzes the reversible cleavage of argininosuccinate to arginine and fumarate. Deficiencies in the enzyme result in the autosomal, recessive disorder argininosuccinic aciduria. Considerable clinical and genetic heterogeneity is associated with this disorder, which is thought to be a consequence of the extensive intragenic complementation identified in patient strains. Our ability to predict genotype-phenotype relationships is hampered by the current lack of understanding of the mechanisms by which complementation can occur. The 3-dimensional structure of wild-type ASL has enabled us to propose that the complementation between two ASL active site mutant subunits, Q286R and D87G, occurs through a regeneration of functional active sites in the heteromutant protein. We have reconstructed this complementation event, both in vivo and in vitro, using recombinant proteins and have confirmed this hypothesis. The complementation events between Q286R and two nonactive site mutants, M360T and A398D, have also been characterized. The M360T and A398D substitutions have adverse effects on the thermodynamic stability of the protein. Complementation between either the M360T or the A398D mutant and the stable Q286R mutant occurs through the formation of a more stable heteromeric protein with partial recovery of catalytic activity. The detection and characterization of a novel complementation event between the A398D and D87G mutants has shown how complementation in patients with argininosuccinic aciduria may correlate with the clinical phenotype.

High-throughput development and characterization of a genomewide collection of gene-based single nucleotide polymorphism markers by chip-based matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

We describe here a system for the rapid identification, assay development, and characterization of gene-based single nucleotide polymorphisms (SNPs). This system couples informatics tools that mine candidate SNPs from public expressed sequence tag resources and automatically designs assay reagents with detection by a chip-based matrix-assisted laser desorption/ionization time-of-flight mass spectrometry platform. As a proof of concept of this system, a genomewide collection of reagents for 9,115 gene-based SNP genetic markers was rapidly developed and validated. These data provide preliminary insights into patterns of polymorphism in a genomewide collection of gene-based polymorphisms.

Mortality of twins and singletons by gestational age: a varying-coefficient approach

This study used data from the Swedish Medical Birth Registry between 1982 and 1995 to address the question of whether there is higher mortality in twins in relation to singletons of the same gestational age and to examine the optimal gestational age range for twins. A "varying-coefficient approach" was adopted to estimate the gestational age-specific relative and absolute risks of mortality in twins and singletons, adjusting for size at birth and risk factors of short gestational duration. The models showed that twins born between 29 and 37 weeks of gestation had lower mortality than did singletons of the same gestational age. Twins born at older gestational age had higher mortality than did their singleton counterparts, because longer gestational duration was more advantageous to singletons than to twins. Without adjustment for size at birth, there was an upturn of mortality in twins born after 38 weeks. It is postulated that twins have better health than singletons initially, but they could not enjoy the benefit of a longer gestational duration as much as singletons could. The optimal gestational age for twins appeared to be 37-39 weeks according to neonatal and infant mortality.

Mass spectrometry of single-stranded restriction fragments captured by an undigested complementary sequence

In this report, we describe a simple and accurate method to analyze restriction fragments using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The two complementary strands of restriction fragments are separated through hybridization to a capture probe, which is a single-stranded undigested fragment. Using the biotin-streptavidin linkage, the hybrid is immobilized on streptavidin-coated magnetic beads. After conditioning the captured restriction fragments, they are eluted from the probe and their molecular weights are determined. The proposed method greatly improves the quality, and reduces the complexity of the mass spectrum by analyzing only one of the complementary strands of restriction fragments.

Crystal structure of a class I alpha1,2-mannosidase involved in N-glycan processing and endoplasmic reticulum quality control

Mannose trimming is not only essential for N-glycan maturation in mammalian cells but also triggers degradation of misfolded glycoproteins. The crystal structure of the class I alpha1, 2-mannosidase that trims Man(9)GlcNAc(2) to Man(8)GlcNAc(2 )isomer B in the endoplasmic reticulum of Saccharomyces cerevisiae reveals a novel (alphaalpha)(7)-barrel in which an N-glycan from one molecule extends into the barrel of an adjacent molecule, interacting with the essential acidic residues and calcium ion. The observed protein-carbohydrate interactions provide the first insight into the catalytic mechanism and specificity of this eukaryotic enzyme family and may be used to design inhibitors that prevent degradation of misfolded glycoproteins in genetic diseases.

Spontaneous epidural haematoma associated with radiation-induced malignant fibrous histiocytoma

We report a case of spontaneous epidural haemorrhage associated with metastatic radiation-induced malignant fibrous histiocytoma of the dural meninges in a patient who had been previously treated for nasopharyngeal carcinoma with radiotherapy.

Anticonvulsant activity of a metabotropic glutamate receptor 8 preferential agonist, (R,S)-4-phosphonophenylglycine

Agonists at group III glutamate metabotropic receptors, such as L-serine-O-phosphate, have pro- and anti-convulsant activities in rodent models. We have used intracerebroventricular administration to test a novel group III agonist, (R,S)-4-phosphonophenylglycine (PPG), that is preferential for mglu(8), against sound-induced seizures in DBA/2 mice. Tonic and clonic seizures are abolished at 15 min (ED(50s) 0.14 [0.04-0.4] nmol, and 3.4 [2.1-5.6] nmol, respectively). The protection against tonic and clonic seizures by 20 nmol PPG is complete for 4 h, diminished by 6 h, and absent by 10 h. In contrast, L-Serine-O-phosphate gives only partial protection against sound-induced clonic seizures for 15-30 min (ED(50) 79 [45-139] nmol) in DBA/2 mice. In genetically epilepsy prone rats sound-induced seizures were blocked 5-60 min after the bilateral administration of PPG, 5-10 nmol, into the inferior colliculus. These data suggest that the mglu(8) receptor is a potential target for novel antiepileptic drugs.