Saline and hydrocarbon-bearing fluids detected in shallow aquifers of southern New Brunswick, Canada: Natural occurrence, or deep migration along faults and industrial wellbores?

Unconventional hydrocarbon production has sparked public concerns for several years, especially regarding potential potable groundwater contamination by hydrocarbons, brines, and various chemicals related to hydraulic fracturing operations. One possible contamination mechanism is upward migration of deep-seated contaminants over large vertical distances, through preferential pathways such as leaky well casings or permeable geological faults. In New Brunswick (Canada), thermogenic hydrocarbons and brackish water were previously reported in shallow water wells, some of them located close to unconventional gas wells or to major faults, but the exact origin of these fluids remained uncertain. The objective of this paper is to determine whether the presence of these fluids is the result of migration from the deep (>1 km) hydrocarbon bearing units (via natural or anthropogenic migration pathways), or whether they rather originate within the shallow aquifer (<100 m) or from intermediate zone. Tracking fluid origin was achieved by fingerprinting compositional and isotopic values of three indicators: 1) water isotopic signature (including tritium (3H), radiocarbon (14CDIC), δ18OH2O, δ2HH2O), 2) salinity (including Na, Ca, K, SO4, Cl, Br, 87Sr/86Sr), and 3) hydrocarbons (compositional data and δ13CCH4). These various analyses were conducted, when relevant, on samples of different matrices composing the hydrogeological system, namely shallow groundwater (12-90 m depth), shallow bedrock gas (8-131 m), and intermediate zone evaporitic rocks (173-332 m); they were compared with previously published values for deep basin brines and gases (1940-3168 m) from the hydrocarbon bearing Carboniferous Albert Formation. This unique suite of indicators, analytes and matrices allowed drawing the conclusion that thermogenic gas and high salinities present in the sampled wells were naturally occurring and originating from shallow and intermediate-zone bedrock units. Results obtained through this approach did not provide any evidence that hydrocarbon wells in this area have acted as preferential migration pathways for deep-seated fluids towards shallow aquifers.

Magnetic Resonance Elastography and Diffusion Weighted Imaging in the Evaluation of Hepatic Fibrosis in Chronic Hepatitis B

BACKGROUND/AIMS: Comparison of the accuracy of magnetic resonance elastography (MRE) and diffusion weighted imaging (DWI) for the diagnosis of liver fibrosis in patients with chronic hepatitis B (CHB). METHODS: In this retrospective analysis, we investigated 63 patients with CHB and liver fibrosis. DWI was performed with both breath-hold (DWI-BH) and free-breathing (DWI-FB) sequences (b=0, 500). The mean liver stiffness and apparent diffusion coefficient (ADC) were calculated by drawing regions of interest maps. Fibrosis staging according to the METAVIR system was independently performed by an experienced pathologist. A receiver operating curve (ROC) analysis was conducted to determine the accuracy of MRE, DWI-BH and DWI-FB in the detection and stratification of liver fibrosis. The performance of the detection of significant fibrosis (≥F2), advanced fibrosis (≥F3), and cirrhosis (F4) was also evaluated by comparing areas under the ROC. RESULTS: There was a moderate and significantly negative correlation between the ADC values and liver stiffness. The accuracies for the detection of ≥F2/≥F3/F4 stage fibrosis with DWI-FB, DWI-BH and MRE were 0.84/0.76/0.72, 0.72/0.83/0.79 and 0.99/0.99/0.98, respectively. The performance of MRE was significantly better than DWI-FB and DWI-BH. There were no significant differences between the performance of DWI-FB and DWI-BH. CONCLUSIONS: MRE is more accurate than DWI for the detection and stratification of liver fibrosis in CHB.

Financial returns on R&D: looking back at history, looking forward to adaptive licensing.

Investment in R&D for drugs launched in the late 1970s to early 1990s generated good returns for investors. R&D was inexpensive. Clinical trial success rates were high. Consumption was increasing. Drug prices were outstripping inflation, which raised profit margins. Tax rates were falling. However, returns on R&D have been falling since the early 1990s given rising clinical trial costs, rising trial failure rates, and lower consumption growth in developed markets. Many investors believe that average financial returns on today's R&D will be below the cost of capital, particularly if US drug price inflation moderates. Thus R&D investment by major drug companies is flat or perhaps falling in real terms. Various regulatory initiatives have tried to streamline clinical development and approval. The latest is Adaptive Licensing (AL). The near-term effect of AL on industry-level financial returns will be modest. AL will, however, be salient for decisions to invest in specific trials and may make it easier for smaller companies to fund development. AL could become more important in the long run if it helps shift industry, regulators, and payers from what has been an increasingly linear model of innovation; predicated on the ideas that basic science predicts, trials test predictions, and trial results form a complete description of a drug's attributes. History shows that many drugs become important because doctors and patients discover utility that was not initially apparent to regulators, payers, or investors. One hope for AL, therefore, is that it will bring more acceptably safe chemical diversity into real world use at lower R&D cost.

First outbreak of PVL-positive nonmultiresistant MRSA in a neonatal ICU in Australia: comparison of MALDI-TOF and SNP-plus-binary gene typing.

The purpose of this brief report is to describe the first outbreak of a community-associated nonmultiresistant and PVL-positive MRSA strain (CC30) in a neonatal intensive care unit in Australia. The utility of matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) for microbial typing is compared with single nucleotide polymorphism (SNP) plus binary gene analysis. The composite correlation index analysis of the MALDI-TOF-MS data demonstrated the similar inter-strain relatedness found with the SNP-plus-binary gene typing used to confirm the outbreak. The evolving spread of MRSA emphasizes the importance of surveillance, infection control vigilance and the ongoing investigation of rapid typing methods for MRSA.

A probable new Helicobacter species isolated from a patient with bacteremia.

A probable new Helicobacter species was isolated from the blood of a 14-month-old aboriginal child who presented with vomiting, diarrhea, fever, and dry cough. The most similar 16S rRNA gene sequence was that of Helicobacter fennelliae CCUG 18820(T) but the new sequence differed from it by at least 32 base substitutions and by the presence of a large (353-nucleotide) intervening sequence.

Intracranial fibromuscular dysplasia in a six-year-old child: a rare cause of childhood stroke.

Intracranial fibromuscular dysplasia is a nonatheromatous angiopathy that most commonly affects adult women and is rarely recognized in children. Symptoms include stroke and headache, although the vasculopathy may be asymptomatic. Diagnosis is based on angiographic appearance, commonly described as a "string of beads." The etiology of intracranial fibromuscular dysplasia is not known, although possible causes include genetic predisposition, trauma, and underlying connective tissue disease. Treatment of intracranial fibromuscular dysplasia is largely supportive once symptoms become manifest. We report a 6-year-old girl who presented to our center for further evaluation of a large left middle cerebral artery distribution infarction. The patient was previously healthy, without known risk factors for stroke. Initial symptoms consisted of a dense global aphasia and a right hemiparesis. On arrival, the patient's aphasia had improved but she continued to have significant deficits in both receptive and expressive language as well as residual right hemiparesis. Magnetic resonance imaging and conventional angiographic studies demonstrated characteristic beading of the distal portion of the left internal carotid artery, as well as the proximal middle cerebral artery. Laboratory evaluation, echocardiogram, and renal ultrasound were normal. The renal vasculature did not demonstrate evidence of intracranial fibromuscular dysplasia. In conclusion, intracranial fibromuscular dysplasia should be considered in the differential diagnosis of childhood stroke. When recognized, other sites of vascular involvement should be sought, and consideration of underlying disorders is important, as connective tissue disorders have been associated with a propensity to develop this vascular abnormality. Careful follow-up is warranted, due to possible progression of disease.

Normal brain development and aging: quantitative analysis at in vivo MR imaging in healthy volunteers.

PURPOSE: To quantitate neuroanatomic parameters in healthy volunteers and to compare the values with normative values from postmortem studies. MATERIALS AND METHODS: Magnetic resonance (MR) images of 116 volunteers aged 19 months to 80 years were analyzed with semiautomated procedures validated by means of comparison with manual tracings. Volumes measured included intracranial space, whole brain, gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF). Results were compared with values from previous postmortem studies. RESULTS: Whole brain and intracranial space grew by 25%-27% between early childhood (mean age, 26 months; age range, 19-33 months) and adolescence (mean age, 14 years; age range, 12-15 years); thereafter, whole-brain volume decreased such that volunteers (age range, 71-80 years) had volumes similar to those of young children. GM increased 13% from early to later (6-9 years) childhood. Thereafter, GM increased more slowly and reached a plateau in the 4th decade; it decreased by 13% in the oldest volunteers. The GM-WM ratio decreased exponentially from early childhood through the 4th decade; thereafter, it gradually declined. In vivo patterns of change in the intracranial space, whole brain, and GM-WM ratio agreed with published postmortem data. CONCLUSION: MR images accurately depict normal patterns of age-related change in intracranial space, whole brain, GM, WM, and CSF. These quantitative MR imaging data can be used in research studies and clinical settings for the detection of abnormalities in fundamental neuroanatomic parameters.

Nurses can impact the effects of Alzheimer's disease.

Nurses should be leaders in the effort to improve a health care crisis such as AD. By uniting, nurses have the ability to impact the effects of AD. Nurses can best do this by belonging to and supporting their professional organization, ANA/NCNA. Nurses should feel morally obligated to promote any action that improves public health and quality of life. In the role of clinician, nurses can benefit clients, caregivers, and society by promoting the client's optimal function. This can be done by involving them in therapeutic mental and/or physical exercises. Coordinating and collaborating with other disciplines, such as physical therapy can also be beneficial. In conclusion, with appropriate action, the nursing profession has the ability to impact the effects of AD on our society.

The lymphocytosis-promoting agent pertussis toxin affects virus burden and lymphocyte distribution in the SIV-infected rhesus macaque.

Pertussis toxin from the gram-negative bacterium Bordetella pertussis is an ADP-ribosylase that modifies Gi proteins in mammalian lymphocytes and inhibits their capacity to traffic from blood into lymphoid tissues. We used this compound to induce lymphocytosis in rhesus macaques and to study its effects on SIV infection. Pertussis toxin injected at 25 micrograms/kg induced a transient lymphocytosis that peaked 3-8 days after administration and caused a rapid, transient decrease in the frequency of infectious cells in blood as judged by in vitro virus isolation assays. Lymphocyte subsets were altered during the lymphocytosis interval and sustained changes in CD8+ T cell levels were noted as long as 53 days after pertussis toxin injection. In situ hybridization studies showed that pertussis toxin altered the distribution of viral RNA in lymph nodes during the interval of lymphocytosis, and caused long-term changes with decreased virus replication in some tissue specimens.

Intrarectal transmission of simian immunodeficiency virus in rhesus macaques: selective amplification and host responses to transient or persistent viremia.

Intrarectal simian immunodeficiency virus (SIV) infection in rhesus macaques is a model for sexual transmission of primate retroviruses. Phylogenetic studies on envelope gene sequences that were present in blood following intrarectal SIV inoculation provided evidence for selective amplification of a subset of viruses present in the inoculum and defined one amino acid sequence uniquely associated with intrarectal infection. Both persistent and transient viremia states were observed after intrarectal infection. Immune responses in persistently infected animals accounted for slower rates of disease progression despite the presence of highly pathogenic viruses that were documented by transfusion studies. Transient viremia elicited protective immunity against subsequent intrarectal virus challenge but did not protect against intravenous virus challenge. Transient viremia usually but not always led to self-limiting infection. In one animal, we documented a relapse to active viremia long after the initial transient viremia. SIV transmission across mucosal barriers affects pathogenesis in the short term by limiting the types of viruses established in the host and in the longer term by establishing host responses that slow disease progression despite the presence of highly pathogenic viruses in blood.

Diagnosis of pericardial abnormalities by 2D-echo: a pathology-echocardiography correlation in 85 patients.

A blinded pericardial echocardiography-pathology correlation was performed using 85 pericardiectomy or autopsy patients. All patients had two-dimensional (2D)-echocardiography performed within 6 months of autopsy or surgery. 2D-echocardiography was able to detect pericardial abnormalities in 35% of patients with a pathologic pericardium. Obliterative processes, such as fibrosis after open-heart surgery, were particularly not well detected echocardiographically. A specificity of 90% to detect pericardial abnormalities is reported. Acute fibrin strands, malignancies, and chronic fibrous connective tissue involving the pericardium were recognized as abnormal. Interobserver variability does exist, but overall reporting was similar. Specific 2D-echocardiographic signs of pericardial disease require prospective validation including direct pathologic correlation.

Identification of false positive exercise tests with use of electrocardiographic criteria: a possible role for atrial repolarization waves.

Atrial repolarization waves are opposite in direction to P waves, may have a magnitude of 100 to 200 mu V and may extend into the ST segment and T wave. It was postulated that exaggerated atrial repolarization waves during exercise could produce ST segment depression mimicking myocardial ischemia. The P waves, PR segments and ST segments were studied in leads II, III, aVF and V4 to V6 in 69 patients whose exercise electrocardiogram (ECG) suggested ischemia (100 mu V horizontal or 150 mu V upsloping ST depression 80 ms after the J point). All had a normal ECG at rest. The exercise test in 25 patients (52% male, mean age 53 years) was deemed false positive because of normal coronary arteriograms and left ventricular function (5 patients) or normal stress single photon emission computed tomographic thallium or gated blood pool scans (16 patients), or both (4 patients). Forty-four patients with a similar age and gender distribution, anginal chest pain and at least one coronary stenosis greater than or equal to 80% served as a true positive control group. The false positive group was characterized by 1) markedly downsloping PR segments at peak exercise, 2) longer exercise time and more rapid peak exercise heart rate than those of the true positive group, and 3) absence of exercise-induced chest pain. The false positive group also displayed significantly greater absolute P wave amplitudes at peak exercise and greater augmentation of P wave amplitude by exercise in all six ECG leads than were observed in the true positive group.(ABSTRACT TRUNCATED AT 250 WORDS)

Chylothorax: a complication of the nephrotic syndrome.

A 50-yr-old man with the nephrotic syndrome developed a chylothorax that was shown to be due to transdiaphragmatic movement of chylous ascites. Because a significant number of patients with nephrotic syndrome have been reported to have chylous ascites, the possibility that chylothorax is due to movement of chylous ascites into the pleural space should be considered prior to surgical intervention directed toward repair of the thoracic duct.