Immunoglobulins associated with elevated riboflavin binding by plasma from cancer patients

Plasma from 182 patients with different malignant diseases was tested for riboflavin binding by immunoglobulins, which have been recently identified as major carriers of this micronutrient. A wide range of binding (5.9 to 130 pmole/ml plasma) was observed, and significant elevations were found for patients having breast cancer (21.2 +/- 1.9, P less than 0.05) and melanoma (25.7 +/- 1.9, P less than 0.001) compared to controls (15.5 +/- 1.9). The proteins responsible for a majority of the higher binding were identified as immunoglobulins, based on their elution from gel filtration columns and the removal of 57-88% of the non-albumin binding by treating of plasma with Protein A-agarose. The binding was only weakly related to the total concentration of immunoglobulins (r = 0.11 by linear regression analysis), however, and is apparently due to a subclass that is elevated in some types of cancer. Elevated levels of these immunoglobulins may contribute to the lower urinary levels and clearance of riboflavin in cancer.     

Comparison of Woodland Caribou Calving Areas Determined by Movement Patterns Across Northern Ontario

Adult female survival and calf recruitment influence population dynamics, but there is limited information on calving and neonatal mortality of boreal woodland caribou (Rangifer tarandus caribou; caribou) in Ontario, Canada. We identified calf parturition sites and 5-week neonatal mortality using a movement-based approach across 3 northern Ontario study regions (Pickle Lake, Nakina, and Cochrane) that vary in their capacity to support caribou populations. In comparing 22 caribou-years of video-collar footage during 2010–2013 to predictions of the movement-based approach, we found live parturition events were 100% correctly classified, date of parturition was within 1.08 ± 0.28 ( ± SE) days, and mortality events up to 5 weeks postpartum were 88% correctly classified. Across study regions, 87% of 186 caribou were pregnant and 76% of 107 caribou-years indicated birth events with median parturition dates a week later in Cochrane (23 May) than in Pickle Lake (17 May) and Nakina (16 May). Based on selection ratios of caribou-years with calves-at-heel (n = 80), caribou consistently selected for lowlands and closed-canopied forests and mostly against early-seral stands (<20 yrs old) and areas near linear features during the neonatal and the post-neonatal period (up to 35 days postpartum). Based on the video footage and movement models, 30% of 81 caribou-years that indicated live births also showed females lost their calf within the first 5 weeks postpartum, with higher risk of neonatal mortality associated with increased use of lowlands and greater postpartum movement rates. This study provides informative metrics of caribou reproduction across northern Ontario that will contribute to future population modeling and identifies important landscape features to be considered in future industrial development and land use planning for caribou conservation. © 2020 The Wildlife Society.     

Sensitive high-performance liquid chromatographic assay for motexafin gadolinium and motexafin lutetium in human plasma

We present new HPLC methods for the quantitation in human plasma of two investigative metallotexaphyrin agents, motexafin gadolinium (Gd-Tex) and motexafin lutetium (Lu-Tex). Each assay uses: the other texaphyrin analogue as an internal standard; protein precipitation with acetonitrile:methanol (50:50, v/v); an ODS reversed-phase column; an isocratic mobile phase of 100 mM ammonium acetate, pH 4.3:acetonitrile:methanol (59:21:20, v/v/v); and absorbance detection at 470 nm. The Gd-Tex assay has a lower limit of quantitation (LLOQ) of 0.01 μM and is linear between 0.01and 30 μM. The Lu-Tex assay has an LLOQ of 0.1 μM and is linear between 0.1 and 30 μM. The assays are suited for in vivo preclinical studies and clinical trials because they require minimal amounts of plasma, are sensitive, and involve a 30-min run time. These assays are important tools for evaluating the potential of Gd-Tex and Lu-Tex as a radiation enhancer and photosensitizer, respectively.     

Modification of responses of newly hatched snails by exposure to odors during development

Predatory marine snail larvae and embryos were exposed to preyodors (oyster, mussel and barnacle) during development. Whenjuvenile snails hatched they were tested by bioassay to determineeffects of this prior odor exposure. Juvenile snails were testedwith oyster, mussel and barnacle odors and with partially purifiedbarnacle odor of known attractiveness. Independent of priorodor exposure, only solutions containing barnacle odor wereattractive. Snails exposed during development to prey odorsnot in themselves attractive were more responsive to barnacleodors than snails that developed in barnacle odors. Snails notexposed to prey odors during development were intermediate intheir responsiveness. Field bioassays showed detectable attractantlevels in an environment containing barnacles. Attractant activitywas not detected in an environment where barnacles were absent.Responses of snails that developed in field odor conditionswere similar to those of snails that developed in the presenceof barnacles. Odor exposure during development is importantin determining future responses of these predatory snails toprey odors. ¹Duke University Marine Laboratory, Pivers Island, Beaufort,NC 28516, USA ²University of Miami RSMAS/MAC 4600 Rickenbacker Causeway, Miami,FL 33149, USA ³Suffolk University, Department of Biology, Beacon Hill, Boston,MA 02114, USA     

Clonal derivation of a rat muscle cell strain that forms contraction-competent myotubes

Summary A muscle cell strain capable of forming contracting myotubes was isolated from an established rat embryo cell line. The myogenic cells, termed rat myoblast omega or RMo cells, have a diploid complement of chromosomes (n=42). In the presence of mitogen-containing growth medium, RMo cells proliferated with a cell generation time of about 12 hours. In mitogen-depleted medium, RMo cells withdrew from the cell cycle and formed myotubes that spontaneously contracted. Differentiated RMo cells produced creatine kinase isozymes in a ratio characteristic of skeletal muscle cells. RMo cells were easy to cultivate. Cells proliferated and differentiated equally well on gelatin-coated or noncoated culture dishes, at clonal or mass culture densities, and in all basal media tested. In most experiments, growth medium consisted of horse serum-containing medium supplemented with either chicken embryo extract or FGF activity; cells proliferated equally well in medium containing unsupplemented calf serum. RMo cells differentiated if growth medium was not replenished regularly. Alternatively, differentiation was induceable by incubation in mitogen-depleted medium consisting of basal medium supplemented either with 10⁻⁶ M insulin, 0.5% serum, or 50% conditioned growth medium. RMo cells were competently transformed with cloned exogenous genes. Because it forms functional myofibrils, the RMo cell line constitutes a useful model system for studying the cell biology and biochemistry of proteins involved in contractile apparatus assembly and muscle disease. This work was supported by NIH research grant GM34432 and Research Career Development Award AG00334. Editor's Statement This report documents the characterization of a differentiating rat cell line that does not show the karyotypic shift toward polyploidy usually observed in rodent cell lines. Investigators already are finding this line valuable in studies of regulation of growth and differentiation.     

Intercellular signaling in glial cells: calcium waves and oscillations in response to mechanical stimulation and glutamate.

Intercellular Ca2+ signaling in primary cultures of glial cells was investigated with digital fluorescence video imaging. Mechanical stimulation of a single cell induced a wave of increased [Ca2+]i that was communicated to surrounding cells. This was followed by asynchronous Ca2+ oscillations in some cells. Similar communicated Ca2+ responses occurred in the absence of extracellular Ca2+, despite an initial decrease in [Ca2+]i in the stimulated cell. Mechanical stimulation in the presence of glutamate induced a typical communicated Ca2+ wave through cells undergoing asynchronous Ca2+ oscillations in response to glutamate. The coexistence of communicated Ca2+ waves and asynchronous Ca2+ oscillations suggests distinct mechanisms for intra- and intercellular Ca2+ signaling. This intercellular signaling may coordinate cooperative glial function.     

Coronary vasodilation caused by intravenous cocaine in the anesthetized beagle

The aim of this study was to determine the effect of intravenous cocaine on the coronary circulation in the dog. Sixteen beagles separated into three groups were administered either cocaine (n = 8) or lidocaine (n = 4) at doses of 0.4, 2.0, and 10.0 mg/kg under conditions of constant coronary blood flow. A third group of beagles (n = 4) was administered cocaine under conditions of natural coronary blood flow. In the first group, the lowest dose of cocaine had no significant effect on coronary perfusion pressure, even though it increased mean systemic arterial pressure by 10% (p less than 0.05). The second two doses decreased coronary perfusion pressure by 13 (p less than 0.05) and 68% (p less than 0.05), respectively. In the second group, the lowest dose of lidocaine did not significantly affect coronary perfusion pressure. However, the second two doses significantly decreased coronary perfusion pressure by 22 (p less than 0.05) and 45% (p less than 0.05), respectively. Under conditions of natural coronary blood flow and coronary perfusion pressure, these same doses of cocaine increased coronary blood flow by 25, 63, and 175%, respectively. All coronary vascular responses occurred 60 s after administration of cocaine or lidocaine. We conclude that cocaine causes rapid, dose-dependent coronary vasodilation in the anesthetized beagle. The coronary vasodilation appears to be related to cocaine's known, local anesthetic properties.     

Statistical Tools and Status Symbols

This paper sets the stage for a series of edited papers which follow. It is argued that obvious statistical blunders (mortal sins) have not dissappeared entirely from the aging literature, but that the most frequent error now is that of choosing a less powerful analytic solution when a more powerful (and equally applicable) one is at hand (a venial sin). Clearly, it is argued, power must be considered in relationship to the theoretical model, the condition of the data set, and the research question. Editors and reviewers, it is argued, must cut through the “glitter” of new fads and the security of tradition in order to objectively consider the merits of new statistical applications. More importantly, without knowledge of the issues, limitations, and advantages of contemporary and emerging analytic techniques, authors cannot make good analytic choices and defend them effectively. The time between presentation of innovative approaches in the quantitative journals and application in the aging literature contributes to traditionalism in data analysis. Overzealousness by advocates of new approaches often contributes to premature embracing of them. Thus the papers that follow were designed to bring new methods to the “working-researcher” with a frank appraisal of assumptions, proper and improper applications, and limitations. Authors of these papers were challenged to communicate in plain and understandable terms and to provide practical examples.