Diagnostic Performance of Magnetic Resonance Cholangiopancreatography in Malignant Obstructive Jaundice

Malignant obstructive jaundice is caused by tumors arising from the head of the pancreas and biliary tree, or seen due to secondary metastases in the porta hepatis lymph nodes. Magnetic resonance cholangiopancreatography (MRCP) is a non-invasive diagnostic technique that can be used for imaging the entire biliary tree and pancreatic duct system. The objective of this study was to evaluate the accuracy of MRCP in the diagnosis of malignant obstructive jaundice. The methods used involved comparative review of the images obtained by using magnetic resonance imaging and MRCP as well as comparison between MRCP- and pathology-based diagnoses. The accuracy of MRCP-based diagnosis of malignant obstructive jaundice was analyzed. Our data show that the positive rate of anatomical diagnosis and the detection rate of bile ducts on the proximal side of obstruction are 100%. The diagnostic accuracy of malignant obstruction was 82.9%. MRCP was found to have high diagnostic specificity for determining the location and extent of obstruction. We, therefore, concluded that MRCP had significance for clinical diagnosis of malignant obstructive jaundice. The positive rate of localization diagnosis was 100%. Distinguishing the quality of obstruction was also important. The diagnostic accuracy of MRCP for malignant obstructive jaundice was remarkably higher.     

The Hidden Cost of Housing Practices: Using Noninvasive Imaging to Quantify the Metabolic Demands of Chronic Cold Stress of Laboratory Mice

Laboratory mice routinely are housed at 20 to 22 °C—well below the murine thermoneutral zone of 29 to 34 °C. Chronic cold stress requires greater energy expenditure to maintain core body temperature and can lead to the failure of mouse models to emulate human physiology. We hypothesized that mice housed at ambient temperatures of 20 to 22 °C are chronically cold-stressed, have greater energy expenditure, and have high glucose utilization in brown adipose tissue. To test our hypotheses, we used indirect calorimetry to measure energy expenditure and substrate utilization in C57BL/6J and Crl:NU-Foxn1^nu nude mice at routine vivarium (21 °C), intermediate (26 °C), and heated (31 °C) housing temperatures. We also examined the activation of interscapular brown adipose tissue, the primary site of nonshivering thermogenesis, via thermography and glucose uptake in this region by using positron emission tomography. Energy expenditure of mice was significantly higher at routine vivarium temperatures compared with intermediate and heated temperatures and was associated with a shift in metabolism toward glucose utilization. Brown adipose tissue showed significant activation at routine vivarium and intermediate temperatures in both hirsuite and nude mice. Crl:NU-Foxn1^nu mice experienced greater cold stress than did C57BL/6J mice. Our data indicate mice housed under routine vivarium conditions are chronically cold stress. This novel use of thermography can measure cold stress in laboratory mice housed in vivaria, a key advantage over classic metabolic measurement tools. Therefore, thermography is an ideal tool to evaluate novel husbandry practices designed to alleviate murine cold stress.Abbreviations: BAT, brown adipose tissue; EPR, entropy production rate; PET, positron emission tomography; ROI, region of interest; RQ, respiratory quotient; VCO₂, volume of carbon dioxide produced; VO₂, volume of oxygen consumedLaboratory mice routinely are housed at ‘room temperature,’ that is, 20 to 22 °C. Room temperature is within the recommendations of the Guide for the Care and Use of Laboratory Animals¹⁴ but is well below the murine thermoneutral zone of 29 to 34 °C.^3,17 Systemic physiologic cold stress creates a much greater energy demand on mice than humans due to the surface area to volume ratio. Mice housed at routine vivarium temperatures have greater oxygen consumption and feed intake than at thermoneutral temperatures (30 °C).^5,27 Ultimately, this difference may adversely affect translational research, sometimes in unpredictable ways.^11,17 For example, mice housed at temperatures below their thermoneutral zone have a blunted response to LPS-induced fever and lack the classic early-phase hypothermia, demonstrating impaired immune function.²² In another example, blood pressure and heart rate are significantly elevated at routine vivarium temperatures compared with thermoneutral temperatures,²³ again demonstrating that rodent physiology is perturbed under such housing conditions.Mammals defend their body temperature through a series of mechanisms that progressively increase in energy cost: behavior,¹⁰ insulative response,⁷ and thermogenesis.³ Behavioral thermoregulation is the principle mechanism that enables the survival of small rodents, however behavioral adaptations of laboratory rodents housed in barren cages are limited compared with those of their wild counterparts; wild rodents adapt to cold stress through techniques like seeking shelter, burrowing, and building nests.^9,10 The insulative response shunts blood from peripheral sites toward core organs to conserve heat.⁷ Once the low-energy cold-adaptive responses are overwhelmed, mammals maintain core body temperature by increasing energy expenditure via shivering and nonshivering thermogenesis.^9,19 Rodents, arctic mammals, and infant mammals primarily rely on nonshivering thermogenesis to preserve core body temperature.²Nonshivering thermogenesis is achieved through mitochondria-rich brown adipose tissue (BAT). The largest deposits of rodent BAT are located in the interscapular region. BAT produces heat rapidly via the oxidative combustion of glucose and triglycerides.^2,6 BAT is rich in β₃-adrenergic receptors, and its activation is mediated primarily by the sympathetic nervous system.² BAT responds within minutes to the sensation of cold. When active, rodent BAT is highly metabolic and can receive as much as 40% of the cardiac outflow.⁷Given our group''s experience with preclinical metabolic imaging,⁸ we hypothesized that the cold stress imposed by routine husbandry temperatures (21 °C) induces a global shift toward glucose-dependent metabolism that is driven by nonshivering thermogenesis. Moreover, we hypothesized that athymic nude (Crl:NU-Foxn1^nu) mice housed at room temperatures experience significantly greater energy expenditure and glucose-dependent metabolism than do hirsute (C57BL/6J) mice.To test our hypotheses, we measured energy expenditure (entropy production rate, EPR, cal/min) and metabolic substrate utilization via indirect calorimetry⁶ and interscapular BAT heat production via infrared thermography and BAT glucose utilization by fluorodeoxyglucose positron emission tomography (PET) at various environmental temperatures, ranging from routine vivarium temperature (21 °C) to heat-supported temperatures (31 °C). Briefly, indirect calorimetry measures O₂ consumption (VO₂) and CO₂ production (VCO₂) to enable the calculation of the energy expenditure of the organism according to the stoichiometric formulas of biologic combustion:With these formulas, indirect calorimetry can also be used to calculate global glucose and lipid utilization using the respiratory quotient (RQ), a unitless ratio between VCO₂:VO₂.⁵ An RQ of 0.7 is indicative of the use of lipid as the primary substrate of biologic combustion, whereas an RQ of 1.0 is indicative of the primary use of glucose (for additional information, see reference 6).     

Prognostic Value of Components of Body Composition in Patients Treated with Targeted Therapy for Advanced Renal Cell Carcinoma: A Retrospective Case Series

BackgroundTo evaluate the association between various components of body composition and overall survival of patients treated with targeted therapies for advanced renal cell carcinoma.MethodsThis retrospective study included 124 Chinese patients with advanced renal cell carcinoma who had been treated with targeted therapy from 2008 to 2012 at Fudan University Cancer Center. The L3 plane from a computed tomography scan was analyzed. Area and density were recorded as quantitative and quality measures. Univariate and multivariate Cox proportion hazard regression models were constructed to calculate the crude and adjusted hazard ratio (HR) of various components of body composition for overall survival. X-tile software was used to search for optimal cutoffs for male and female patients and the concordance index evaluated incremental changes in prognostication.ResultsAfter adjusting for age, sex and Heng risk stratification, only visceral adipose tissue index (HR 0.981, p = 0.002) and subcutaneous adipose tissue index (HR 0.987, p = 0.048) were independently associated with overall survival. Visceral adipose tissue remained a significant prognostic factor (HR 0.997, p = 0.005) when the influence of body mass index was included. Using defined cutoffs, patients with low VAT had double the death rate (p = 0.007). Visceral adipose tissue also added significant benefit to Heng risk stratification. Further exploratory analysis revealed that visceral adipose tissue may be an indicator of nutritional status in patients with advanced renal cell carcinoma.ConclusionRadiologic measurement of VAT is an independent prognostic factor for Asian patients treated with targeted therapy for advanced renal cell carcinoma.     

Exaggerated pulmonary hypertension with monocrotaline in rats susceptible to chronic mountain sickness

Colice, Gene L., Nicholas Hill, Yan-Jie Lee, Hongkai Du,James Klinger, James C. Leiter, and Lo-Chang Ou. Exaggerated pulmonary hypertension with monocrotaline in rats susceptible tochronic mountain sickness. J. Appl.Physiol. 83(1): 25-31, 1997.Hilltop (H) strainSprague-Dawley rats are more susceptible to chronic mountain sicknessthan are the Madison (M) strain rats. It is unclear what role pulmonaryvascular remodeling, polycythemia, and hypoxia-induced vasoconstrictionplay in mediating the more severe pulmonary hypertension that developsin the H rats during chronic hypoxia. It is also unclear whether theincreased sensitivity of the H rats to chronic mountain sickness isspecific for a hypoxia effect or, instead, reflects a generalpropensity toward the development of pulmonary hypertension.Monocrotaline (MCT) causes pulmonary vascular remodeling and pulmonaryhypertension. We hypothesized that the difference in the pulmonaryvascular response to chronic hypoxia between H and M rats reflects anincreased sensitivity of the H rats to any pulmonary hypertensivestimuli. Consequently, we expected the two strains to also differ intheir susceptibility to MCT-induced pulmonary hypertension. Pulmonaryarterial pressures in conscious H and M rats were measured 3 wk after asingle dose of MCT, exposure to a simulated high altitude of 18,000 ft(barometric pressure = 380 mmHg), and administration of a single doseof saline as a placebo. The H rats had significantlyhigher pulmonary arterial pressures and right ventricular weights afterMCT and chronic hypoxia than did the M rats. The H rats also had morepulmonary vascular remodeling, i.e., greater wall thickness as apercentage of vessel diameter, after MCT and chronic hypoxia than didthe M rats. The H rats had significantly lower arterialPO₂ than did the M rats after MCT,but the degree of hypoxemia was mild [arterialPO₂ of 72.5 ± 0.8 (SE) Torr for Hrats vs. 77.4 ± 0.8 Torr for M rats after MCT]. The H ratshad lower arterial PCO₂ and largerminute ventilation values than did the M rats after MCT. Theseventilatory differences suggest that MCT caused more severe pulmonaryvascular damage in the H rats than in the M rats. These data supportthe hypothesis that the H rats have a general propensity to developpulmonary hypertension and suggest that differences in pulmonaryvascular remodeling account for the increased susceptibility of H rats,compared with M rats, to both MCT and chronic hypoxia-induced pulmonaryhypertension.

     

Turning publicly available gene expression data into discoveries using gene set context analysis

Gene Set Context Analysis (GSCA) is an open source software package to help researchers use massive amounts of publicly available gene expression data (PED) to make discoveries. Users can interactively visualize and explore gene and gene set activities in 25,000+ consistently normalized human and mouse gene expression samples representing diverse biological contexts (e.g. different cells, tissues and disease types, etc.). By providing one or multiple genes or gene sets as input and specifying a gene set activity pattern of interest, users can query the expression compendium to systematically identify biological contexts associated with the specified gene set activity pattern. In this way, researchers with new gene sets from their own experiments may discover previously unknown contexts of gene set functions and hence increase the value of their experiments. GSCA has a graphical user interface (GUI). The GUI makes the analysis convenient and customizable. Analysis results can be conveniently exported as publication quality figures and tables. GSCA is available at https://github.com/zji90/GSCA. This software significantly lowers the bar for biomedical investigators to use PED in their daily research for generating and screening hypotheses, which was previously difficult because of the complexity, heterogeneity and size of the data.     

<Emphasis Type="Italic">Agrobacterium tumefaciens</Emphasis>-mediated transformation of <Emphasis Type="Italic">Botryosphaeria dothidea</Emphasis>

Botryosphaeria dothidea is a severe causal agent of die-back and cankers of many woody plants and causes great losses in many regions. The pathogenic mechanism of this pathogen has not been well explored due to lack of mutants and genetic information. In this study, we developed an Agrobacterium tumefaciens-mediated transformation (ATMT) protocol for B. dothidea protoplasts using vector pBHt2 containing the hph gene as a selection marker under the control of trp C promoter. Using this protocol we successfully generated the B. dothidea transformants with efficiency about 23 transformants per 10⁵ protoplasts. This is the first report of genetic transformation of B. dothidea via ATMT and this protocol provides an effective tool for B. dothidea genome manipulation, gene identification and functional analysis.