Continuous measurements of methane mixing ratios from ice cores

This work presents a new, field-deployable technique for continuous, high-resolution measurements of methane mixing ratios from ice cores. The technique is based on a continuous flow analysis system, where ice core samples cut along the long axis of an ice core are melted continuously. The past atmospheric air contained in the ice is separated from the melt water stream via a system for continuous gas extraction. The extracted gas is dehumidified and then analyzed by a Wavelength Scanned-Cavity Ring Down Spectrometer for methane mixing ratios. We assess the performance of the new measurement technique in terms of precision (±0.8 ppbv, 1σ), accuracy (±8 ppbv), temporal (ca. 100 s), and spatial resolution (ca. 5 cm). Using a firn air transport model, we compare the resolution of the measurement technique to the resolution of the atmospheric methane signal as preserved in ice cores in Greenland. We conclude that our measurement technique can resolve all climatically relevant variations as preserved in the ice down to an ice depth of at least 1980 m (66 000 yr before present) in the North Greenland Eemian Ice Drilling ice core. Furthermore, we describe the modifications, which are necessary to make a commercially available spectrometer suitable for continuous methane mixing ratio measurements from ice cores.

Centennial mineral dust variability in high-resolution ice core data from Dome C, Antarctica

Ice core data from Antarctica provide detailed insights into the characteristics of past climate, atmospheric circulation, as well as changes in the aerosol load of the atmosphere. We present high-resolution records of soluble calcium (Ca2+), non-sea-salt soluble calcium (nssCa2+), and particulate mineral dust aerosol from the East Antarctic Plateau at a depth resolution of 1 cm, spanning the past 800 000 years. Despite the fact that all three parameters are largely dust-derived, the ratio of nssCa2+ to particulate dust is dependent on the particulate dust concentration itself. We used principal component analysis to extract the joint climatic signal and produce a common high-resolution record of dust flux. This new record is used to identify Antarctic warming events during the past eight glacial periods. The phasing of dust flux and CO2 changes during glacial-interglacial transitions reveals that iron fertilization of the Southern Ocean during the past nine glacial terminations was not the dominant factor in the deglacial rise of CO2 concentrations. Rapid changes in dust flux during glacial terminations and Antarctic warming events point to a rapid response of the southern westerly wind belt in the region of southern South American dust sources on changing climate conditions. The clear lead of these dust changes on temperature rise suggests that an atmospheric reorganization occurred in the Southern Hemisphere before the Southern Ocean warmed significantly.

Eosinophilic esophagitis in adults--no clinical relevance of wheat and rye sensitizations

BACKGROUND: Eosinophilic esophagitis (EE) is often associated with concomitant atopic diseases. In children with EE in whom food allergens have been identified as causative factors, elemental and elimination diets result in an improvement or resolution of symptoms. Most adult EE patients are sensitized to aeroallergens, which cross-react with plant-derived food allergens, most commonly to grass pollen and cereals. AIMS OF THE STUDY: To investigate the clinical relevance of the sensitization to wheat and rye, and the efficacy of an allergen-specific elimination diet in adult EE patients. METHODS: Six patients (five men, one women) with permanently active EE sensitized to grass pollen and the cereals wheat and rye underwent a double-blind placebo-controlled food challenge and were kept on an elimination diet avoiding wheat and rye for 6 weeks. RESULTS: The challenge tests with wheat and rye did not provoke any EE symptoms in all patients. The elimination diet failed in reducing disease activity. Although one patient noticed an improvement of symptoms, endoscopic and histopathologic findings remained unchanged. CONCLUSIONS: In adult EE patients, sensitization to wheat and rye does not seem causative for EE. Elimination diet is not a reliable and efficient therapeutic measure in EE patients sensitized to wheat and rye. Low specific immunoglobulin-E levels to wheat and rye may be a consequence of the underlying grass pollen allergy.

Molecules involved in the regulation of eosinophil apoptosis

Apoptosis is the most common form of physiological cell death and a necessary process to maintain cell numbers in multicellular organisms. Eosinophils are constantly produced in the bone marrow and the same numbers die, under normal circumstances, within a relatively short time period. In many eosinophilic inflammatory diseases, reduced eosinophil apoptosis has been described. This mechanism may contribute to increased eosinophil numbers, a phenomenon called eosinophilia. Overexpression of interleukin-5 appears to be crucial for delaying eosinophil apoptosis in many allergic disorders. Survival factor withdrawal leads to the induction of apoptosis. Besides survival cytokines, eosinophil apoptosis is also regulated by death factors. Recent observations suggest a role for mitochondria in conducting eosinophil apoptosis, although the mechanisms that trigger mitochondria to release proapoptotic factors remain less clear. Drugs that specifically induce eosinophil apoptosis might be useful for triggering the resolution of unwanted eosinophilic inflammatory responses.

Quantification of central motor conduction deficits in multiple sclerosis patients before and after treatment of acute exacerbation by methylprednisolone

OBJECTIVE: To compare the effects of intravenous methylprednisolone (IVMP) in patients with relapsing-remitting (RR-MS), secondary progressive (SP-MS), and primary progressive multiple sclerosis (PP-MS). METHODS: Clinical and neurophysiological follow up was undertaken in 24 RR-MS, eight SP-MS, and nine PP-MS patients receiving Solu-Medrol 500 mg/d over five days for exacerbations involving the motor system. Motor evoked potentials (MEPs) were used to measure central motor conduction time (CMCT) and the triple stimulation technique (TST) was applied to assess conduction deficits. The TST allows accurate quantification of the number of conducting central motor neurones, expressed by the TST amplitude ratio. RESULTS: There was a significant increase in TST amplitude ratio in RR-MS (p<0.001) and SP-MS patients (p<0.02) at day 5, paralleling an increase in muscle force. TST amplitude ratio and muscle force remained stable at two months. In PP-MS, TST amplitude ratio and muscle force did not change. CMCT did not change significantly in any of the three groups. CONCLUSIONS: In RR-MS and SP-MS, IVMP is followed by a prompt increase in conducting central motor neurones paralleled by improvement in muscle force, which most probably reflects partial resolution of central conduction block. The lack of similar clinical and neurophysiological changes in PP-MS corroborates previous clinical reports on limited IVMP efficacy in this patient group and points to pathophysiological differences underlying exacerbations in PP-MS.

The quantitative genetic basis of offspring solicitation and parental response in a passerine bird with biparental care

The coevolution of parental investment and offspring solicitation is driven by partly different evolutionary interests of genes expressed in parents and their offspring. In species with biparental care, the outcome of this conflict ma!: be influenced by the sexual conflict over parental investment, Models for the resolution of such family conflicts have made so far untested assumptions about genetic variation and covariation in the parental resource provisioning response and the level of offspring solicitation. Using a combination of cross-fostering and begging playback experiments, we show that, in the great tit (Parus major), (i) the begging call intensity of nestlings depends on their common origin, suggesting genetic variation for this begging display, (ii) only mothers respond to begging calls by increased food provisioning, and (iii! the size of the parental response is positively related to the begging call intensity of nestlings in the maternal but not paternal line. This study indicates that genetic covariation, its differential expression in the maternal and paternal lines and/or early environmental and parental effects need to be taken into account when predicting the phenotypic outcome of the conflict over investment between genes expressed in each parent and the offspring. [References: 36]

The effect of cementing technique on structural fixation of pegged glenoid components in total shoulder arthroplasty

Although loosening of cemented glenoid components is one of the major complications of total shoulder arthroplasty, there is little information about factors affecting initial fixation of these components in the scapular neck. This study was performed to assess the characteristics of structural fixation of pegged glenoid components, if inserted with two different recommended cementing techniques. Six fresh-frozen shoulder specimens and two types of glenoid components were used. The glenoids were prepared according to the instructions and with the instrumentation of the manufacturer. In 3 specimens, the bone cement was inserted into the peg receiving holes (n = 12) and applied to the back surface of the glenoid component with a syringe. In the other 3 specimens, the cement was inserted into the holes (n = 15) by use of pure finger pressure: no cement was applied on the backside of the component. Micro-computed tomography scans with a resolution of 36 microm showed an intact cement mantle around all 12 pegs (100%) when a syringe was used. An incomplete cement plug was found in 7 of 15 pegs (47%) when the finger-pressure technique was used. Cement penetration into the cancellous bone was deeper in osteopenic bone. Application of bone cement on the backside of the glenoid prosthesis improved seating by filling out small spaces between bone and polyethylene resulting from irregularities after reaming or local cement extrusion from a drill hole. The fixation of a pegged glenoid component is better if the holes are filled with cement under pressure by use of a syringe and if cement is applied to the back of the glenoid component than if cement is inserted with pure finger pressure and no cement is applied to the back surface of the component.

Effect of mechanical and antiseptic therapy on peri-implant mucositis: an experimental study in monkeys

OBJECTIVES: This experiment was performed to evaluate clinically and histologically the effect of mechanical therapy with or without antiseptic therapy on peri-implant mucositis lesions in nine cynomolgus monkeys. MATERIAL AND METHODS: Two ITI titanium implants were inserted into each side of the mandibles. After 90 days of plaque control and soft tissue healing, a baseline clinical examination was completed. Peri-implant lesions were induced by placing silk ligatures and allowing plaque to accumulate for 6 weeks. The clinical examination was then repeated, and the monkeys were randomly assigned to three treatment groups: group A, mechanical cleansing only; group B, mechanical cleansing and local irrigation with 0.12% chlorhexidine (CHX) and application of 0.2% CHX gel; and group C, control, no treatment. The implants in treatment groups A and B were treated and maintained according to the assigned treatment for two additional months. At the end of the maintenance period, a final clinical examination was performed and the animals were sacrificed for biopsies. RESULTS: The mean probing depths (PD) values at mucositis were: 3.5, 3.7, and 3.4 mm, and clinical attachment level (CAL) = 3.8, 4.1, and 3.9 mm for treatment groups A, B and C, respectively. The corresponding values after treatment were: PD = 1.7, 2.1, and 2.5 mm, and CAL=2.6, 2.6, and 3.1 mm. ANOVA of mean changes (Delta) in PD and CAL after treatment showed no statistical difference between the treatment groups. Comparison of the mean changes in PD and CAL after treatment yielded statistical differences between the control and treatment groups P < 0.01. According to the t-test, no statistical difference was found between treatment groups A and B for the PD reduction but there was a significant difference for the CAL change, P < 0.03. Group A had significantly more recession and less CAL gain than group B. Non-parametric tests yielded no significant differences in modified plaque index (mPlI) and gingival index (GI) after treatment between both treatment groups. Frequencies and percent distributions of the mPlI and GI scores changed considerably for both treatment groups when compared with the changes in the control group after treatment. With regard to the histological evaluation, no statistical differences existed between the treatments for any linear measurement. The proportion of inflammation found in the mucosal tissues of the control implants was greater than the one found for both treatment groups, P < 0.01. More importantly, both treatment groups showed a similar low proportion of inflammation after 2 months of treatment. CONCLUSIONS: Within the limitations of this experiment, and considering the supportive plaque control rendered, it can be concluded that for pockets of 3-4 mm: (1) mechanical therapy alone or combined with CHX results in the clinical resolution of peri-implant mucositis lesions, (2) histologically, both treatments result in minimal inflammation compatible with health, and (3) the mechanical effect alone is sufficient to achieve clinical and histologic resolution of mucositis lesions.

Guided tissue regeneration/deproteinized bovine bone mineral or papilla preservation flaps alone for treatment of intrabony defects. II: radiographic predictors and outcomes

OBJECTIVES: This study reports the secondary analysis of a randomized-controlled clinical trial designed to assess the efficacy of deproteinized bovine mineral and a collagen membrane in the treatment of intrabony defects. The specific aims of this report are (1) to analyse the radiographic bone changes 1 year after therapy and (2) to assess the association between radiographic defect angle and treatment outcomes. MATERIALS AND METHODS: Baseline and 12-month radiographs were collected from 120 patients with advanced chronic periodontitis from 10 centres in seven countries as part of a multi-centre clinical trial. All patients had at least one intrabony defect > or =3 mm in depth. The treatment consisted of simplified or modified papilla preservation flaps to access the defect. After debridement of the area, a deproteinized bovine mineral and a collagen membrane were applied in the test subjects, and omitted in the controls. Main outcome measures were radiographic bone fill and defect resolution 1 year after surgery. RESULTS: One hundred and twenty pairs of radiographs were obtained, of which 110 pairs were measurable (57 tests and 53 controls). One year after treatment, radiographic resolution of the intrabony component was significantly higher in the test group (3.2+/-1.7 mm) when compared with the controls (1.7+/-1.9 mm). Multivariate analysis indicated that the treatment and the baseline radiographic depth of the intrabony defect significantly influenced the radiographic bone fill of the intrabony defect 1 year following treatment. The percentage of resolution of the defect was influenced by the treatment provided and the baseline plaque score. The baseline radiographic defect angle did not show a significant impact on the clinical and radiographic outcomes. CONCLUSIONS: Regenerative periodontal surgery with a deproteinized bovine bone mineral and a collagen membrane offered additional benefits in terms of radiographic resolution of the intrabony defect and predictability of outcomes with respect to papilla preservation flaps alone.

Influence of various surface treatments on reosseointegration around contaminated implants

The similarity of periodontitis and peri-implantitis demands for the utilization of similar principles for the treatment. Different decontamination methods were available cleaning of implant surfaces contaminated with bacteria. The aim of the present study was to evaluate the effects of various decontamination methods on reosseointegration on contaminated implants. Six mongrel dogs were used. The mandibular 1st molars and all premolars were removed bilaterally. Three months later, experi- mental implants with different surface characters were installed in each sides of the mandible. The implant consisted of two parts; the implant body and an exchangeable intraosseous implant cylinder. After osseointegration, experimental peri-implantitis was induced by cotton ligatures until the bone loss reached the junction of the two segments of the implant. After debridement of the bone defects, three treatment models were performed; (i) contaminated cylinders were removed, pristine cylinders were placed; (ii) contaminated cylinders were cleaned in situ with saline and (iii) contaminated cylinders was removed, cleaned with saline, sterilized by autoclaving. All implants were covered with membranes. After 3 months, histological evaluations were accomplished. The results indicated that in situ saline therapy demonstrated a significant difference at SLA surfaces in bone-implant-contact. Treatment of contaminated implants in situ with saline resulted in resolution of peri-implantitis and bone fill in defects.

Copper induction of lactate oxidase of Lactococcus lactis: a novel metal stress response

Lactococcus lactis IL1403, a lactic acid bacterium widely used for food fermentation, is often exposed to stress conditions. One such condition is exposure to copper, such as in cheese making in copper vats. Copper is an essential micronutrient in prokaryotes and eukaryotes but can be toxic if in excess. Thus, copper homeostatic mechanisms, consisting chiefly of copper transporters and their regulators, have evolved in all organisms to control cytoplasmic copper levels. Using proteomics to identify novel proteins involved in the response of L. lactis IL1403 to copper, cells were exposed to 200 muM copper sulfate for 45 min, followed by resolution of the cytoplasmic fraction by two-dimensional gel electrophoresis. One protein strongly induced by copper was LctO, which was shown to be a NAD-independent lactate oxidase. It catalyzed the conversion of lactate to pyruvate in vivo and in vitro. Copper, cadmium, and silver induced LctO, as shown by real-time quantitative PCR. A copper-regulatory element was identified in the 5' region of the lctO gene and shown to interact with the CopR regulator, encoded by the unlinked copRZA operon. Induction of LctO by copper represents a novel copper stress response, and we suggest that it serves in the scavenging of molecular oxygen.

Intentional replantation for the management of maxillary sinusitis

AIM: To present a case that emphasizes the importance of the use of intentional replantation as a technique to successfully treat a periapical lesion and an odontogenic maxillary sinusitis through the alveolus at the same time. SUMMARY: This case report presents a patient with odontogenic maxillary sinusitis secondary to periapical disease of a maxillary molar that had previously received root canal treatment. The molar was extracted, with drainage and rinsing of the maxillary sinus. The apices were resected extra-orally, the retrograde cavities prepared with ultrasound and retrograde fillings of silver amalgam placed. The tooth was then replanted. After 2 years, the patient was asymptomatic, periapical radiography showed no evidence of root resorption and computed tomography scanning demonstrated the resolution of maxillary sinusitis. Key learning points: *When root canal treatment or periapical surgery cannot be undertaken or has failed, intentional replantation may be considered. *This alternative treatment may be predictable in certain cases.

Late presentation of HIV-infected individuals

Late presentation remains a major concern despite the dramatically improved prognosis realized by ART. We define a first presentation for HIV care during the course of HIV infection as 'late' if an AIDS-defining opportunistic disease is apparent, or if CD4+ T-cells are <200/microl. In the Western world, approximately 10 and 30% of HIV-infected individuals still present with CD4+ T-cells <50 and <200/microl, respectively; estimates are substantially higher for developing countries. Diagnosis and treatment of opportunistic diseases and intense supportive in-hospital care take precedence over ART. Benefits of starting ART without delay, that is, when opportunistic diseases are still active, include faster resolution of opportunistic diseases and a decreased risk of recurrence. The downside of starting ART without delay could include toxicity, drug interactions and immune reconstitution inflammatory syndrome (IRIS). Among asymptomatic or oligosymptomatic individuals presenting late, where ART and primary prophylaxis are initiated, approximately 10-20% will become symptomatic from drug toxicity or undiagnosed opportunistic complications, including IRIS, which require appropriate therapies. In this review we describe late presentation to HIV care, the scale of the problem, the evaluation of a late-presenting patient and challenges associated with initiation of potent antiretroviral therapy (ART) in the setting of acute opportunistic infections and other comorbidities.

Finite element 3D reconstruction of the pulmonary acinus imaged by synchrotron X-ray tomography

The alveolated structure of the pulmonary acinus plays a vital role in gas exchange function. Three-dimensional (3D) analysis of the parenchymal region is fundamental to understanding this structure-function relationship, but only a limited number of attempts have been conducted in the past because of technical limitations. In this study, we developed a new image processing methodology based on finite element (FE) analysis for accurate 3D structural reconstruction of the gas exchange regions of the lung. Stereologically well characterized rat lung samples (Pediatr Res 53: 72-80, 2003) were imaged using high-resolution synchrotron radiation-based X-ray tomographic microscopy. A stack of 1,024 images (each slice: 1024 x 1024 pixels) with resolution of 1.4 mum(3) per voxel were generated. For the development of FE algorithm, regions of interest (ROI), containing approximately 7.5 million voxels, were further extracted as a working subunit. 3D FEs were created overlaying the voxel map using a grid-based hexahedral algorithm. A proper threshold value for appropriate segmentation was iteratively determined to match the calculated volume density of tissue to the stereologically determined value (Pediatr Res 53: 72-80, 2003). The resulting 3D FEs are ready to be used for 3D structural analysis as well as for subsequent FE computational analyses like fluid dynamics and skeletonization.

Induction of Bim limits cytokine-mediated prolonged survival of neutrophils

Under inflammatory conditions, neutrophil apoptosis is delayed due to survival-factor exposure, a mechanism that prevents the resolution of inflammation. One important proinflammatory cytokine involved in the regulation of neutrophil survival/activation is granulocyte-macrophage colony-stimulating factor (GM-CSF). Although GM-CSF mediates antiapoptotic effects in neutrophils, it does not prevent apoptosis, and the survival effect is both time dependent and limited. Here, we identified the proapoptotic Bcl-2 family member Bim as an important lifespan limiting molecule in neutrophils, particularly under conditions of survival factor exposure. Strikingly, GM-CSF induced Bim expression in both human and mouse neutrophils that was blocked by pharmacological inhibition of phosphatidylinositol-3 kinase (PI3K). Increased Bim expression was also seen in human immature bone marrow neutrophils as well as in blood neutrophils from septic shock patients; both cell populations are known to be exposed to GM-CSF under in vivo conditions. The functional role of Bim was investigated using Bim-deficient mouse neutrophils in the presence and absence of the survival cytokines interleukin (IL)-3 and GM-CSF. Lack of Bim expression resulted in a much higher efficacy of the survival cytokines to block neutrophil apoptosis. Taken together, these data demonstrate a functional role for Bim in the regulation of neutrophil apoptosis and suggest that GM-CSF and other neutrophil hematopoietins initiate a proapoptotic counterregulation that involves upregulation of Bim.