492 research outputs found
Avenues of future research in homotransplantation of the liver with particular reference to hepatic supportive procedures, antilymphocyte serum, and tissue typing
Three general areas of research which bear on the developing field of liver transplantation are reviewed. These are: (1) the prospects of obtaining better immunosuppression with particular reference to heterologous antilymphocyte serum; (2) the possible use of antigen matching technics as an advanced indicator of donorrecipient histocompatibility; (3) a simlified system of extracorporeal transplntation designed to provide teporary hepatic support. © 1966
DESCRIPTION OF THE LARVAE OF TWO SPECIES OF \u3ci\u3eHEMIPEPLUS LATREILLE\u3c/i\u3e (COLEOPTERA:MYCTERIDAE)
The key description and illustrations of mouthparts, ocelli, and terminal abdominal segments by Bovinq & Craighead (1931) have been the only information on the larval stages of the genus Hemipeplus Latreille, except for the observation by van Emden (1942) that individuals of the genus would not key properly in Boving & Craighead\u27s key. Their example was of an undescribed species from Cuba. The semidiagrammatic illustrations make it difficult to identify the species illustrated, although it may be H. marginipennis (LeConte). This paper is based on larvae collected by the authors, in each case associated with adults. From the family diagnosis of larval Mycteridae (Crowson & Viedma 1964). Hemipeplus larvae differ noticeably in the form of the sensorium, which Crowson & Viedma describe as “very short, dome-shaped”; in Hemipeplus it is elongate and conical. From the larva of Mycterus (described by Crowson & Viedma 1964) those of Hemipeplus also differ in having five ocelli on each side (cf. two), mala with an uncus and medial pit (cf. without uncus or medial pit), mola ridged (cf. not ridged), cardines not divided (cf. distinctly divided, labial palpi with only one distinct palpomere (cf. with two palpomeres), abdominal asperities absent (cf. asperities present), and different form of spiracle (compare fig. 13 with fig. 4 in Crowson & Viedma 1964). Larvae of Hemipeplus are more similar to that of Eurypus muelleri Seldlitz (described by Costa & Vanin 1977) than to that of Mycterus. As in Hemipeplus, Eurypus larvae possess five ocelli arranged in rows of three and two on each side; two pairs of tubercles at posterior margin of abdominal sternite IX; mala with an uncus, and cardines divided. Hemipeplus larvae differ from those of Mycterus most notably in the form of abdominal tergite IX (see Costa & Vanin 1977:fig. 2 ) . The uncus is located on the mesal margin of the mala in Hemipeplus, whereas it is located on the ventral aspect of the mala in Eurypus
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Leveraging Epidemiology to Improve Risk Assessment.
The field of environmental public health is at an important crossroad. Our current biomonitoring efforts document widespread exposure to a host of chemicals for which toxicity information is lacking. At the same time, advances in the fields of genomics, proteomics, metabolomics, genetics and epigenetics are yielding volumes of data at a rapid pace. Our ability to detect chemicals in biological and environmental media has far outpaced our ability to interpret their health relevance, and as a result, the environmental risk paradigm, in its current state, is antiquated and ill-equipped to make the best use of these new data. In light of new scientific developments and the pressing need to characterize the public health burdens of chemicals, it is imperative to reinvigorate the use of environmental epidemiology in chemical risk assessment. Two case studies of chemical assessments from the Environmental Protection Agency Integrated Risk Information System database are presented to illustrate opportunities where epidemiologic data could have been used in place of experimental animal data in dose-response assessment, or where different approaches, techniques, or studies could have been employed to better utilize existing epidemiologic evidence. Based on the case studies and what can be learned from recent scientific advances and improved approaches to utilizing human data for dose-response estimation, recommendations are provided for the disciplines of epidemiology and risk assessment for enhancing the role of epidemiologic data in hazard identification and dose-response assessment
Description of the larvae of two species of Hemipeplus Latreille (Coleoptera: Mycteridae)
The key description and illustrations of mouthparts, ocelli, and terminal abdominal segments by Bovinq & Craighead (1931) have been the only information on the larval stages of the genus Hemipeplus Latreille, except for the observation by van Emden (1942) that individuals of the genus would not key properly in Boving & Craighead's key. Their example was of an undescribed species from Cuba. The semidiagrammatic illustrations make it difficult to identify the species illustrated, although it may be H. marginipennis (LeConte). This paper is based on larvae collected by the authors, in each case associated with adults. From the family diagnosis of larval Mycteridae (Crowson & Viedma 1964). Hemipeplus larvae differ noticeably in the form of the sensorium, which Crowson & Viedma describe as “very short, dome-shaped”; in Hemipeplus it is elongate and conical. From the larva of Mycterus (described by Crowson & Viedma 1964) those of Hemipeplus also differ in having five ocelli on each side (cf. two), mala with an uncus and medial pit (cf. without uncus or medial pit), mola ridged (cf. not ridged), cardines not divided (cf. distinctly divided, labial palpi with only one distinct palpomere (cf. with two palpomeres), abdominal asperities absent (cf. asperities present), and different form of spiracle (compare fig. 13 with fig. 4 in Crowson & Viedma 1964). Larvae of Hemipeplus are more similar to that of Eurypus muelleri Seldlitz (described by Costa & Vanin 1977) than to that of Mycterus. As in Hemipeplus, Eurypus larvae possess five ocelli arranged in rows of three and two on each side; two pairs of tubercles at posterior margin of abdominal sternite IX; mala with an uncus, and cardines divided. Hemipeplus larvae differ from those of Mycterus most notably in the form of abdominal tergite IX (see Costa & Vanin 1977:fig. 2 ) . The uncus is located on the mesal margin of the mala in Hemipeplus, whereas it is located on the ventral aspect of the mala in Eurypus
Rational Design, Synthesis, and Biological Evaluation of Progesterone-Modified MRI Contrast Agents
SummaryA series of contrast agents for magnetic resonance imaging (MRI) aimed at noninvasively determining the hormone receptor status of cancer in vitro was developed. These MRI contrast agents were prepared by conjugating progesterone to clinically used Gd(III) chelates. These agents exhibited higher progesterone receptor binding affinities in the nanomolar range and intracellular accumulation. High logP values of the modified compounds suggested that the lipophilicity of the steroid conjugates may have contributed to membrane permeability. Synchrotron radiation X-ray fluorescence microscopy and magnetic resonance images revealed that the synthesized conjugates showed the greatest cellular accumulation and significant increase in relaxivity in vitro compared to the previously developed steroid-modified agent. Transcriptional assays using the progesterone response element linked to luciferase indicated that the contrast agents entered the cell, interacted with the biological target, and drove specific progesterone-mediated transcription
A Steroid-Conjugated Contrast Agent for Magnetic Resonance Imaging of Cell Signaling
We have synthesized the first steroid hormone−MR contrast agent conjugate designed to track the cell signaling process upon binding to a gene switch system. The derivative has a high relaxivity and when tested in vitro is active as a progesterone antagonist (RU-486). By combining a transcriptional system and a noninvasive imaging technology, such as MRI, it would be a powerful tool to research the cell signaling pathway in vivo
Cosmogenic \u3csup\u3e26\u3c/sup\u3eAl/\u3csup\u3e10\u3c/sup\u3eBe surface production ratio in Greenland
The assumed value for the cosmogenic 26Al/10Be surface production rate ratio in quartz is an important parameter for studies investigating the burial or subaerial erosion of long-lived surfaces and sediments. Recent models and data suggest that the production ratio is spatially variable and may be greater than originally thought. Here we present measured 26Al/10Be ratios for 24 continuously exposed bedrock and boulder surfaces spanning ~61–77°N in Greenland. Empirical measurements, such as ours, include nuclides produced predominately by neutron-induced spallation with percent-level contributions by muon interactions. The slope of a York regression line fit to our data is 7.3 ± 0.3 (1σ), suggesting that the 26Al/10Be surface production ratio exceeds the commonly used value of 6.75, at least in the Arctic. A higher 26Al/10Be production ratio has implications for multinuclide cosmogenic isotope studies because it results in greater modeled burial durations and erosion rates
Speaking out about gender imbalance in invited speakers improves diversity.
Omissions of qualified women scientists from major meeting programs continue to occur despite a surge in articles indicating persistent gender-discriminatory practices in hiring and promotion, and calls for gender balance in conference organizing committees
The transplantation of gastrointestinal organs
Over a period of 33 years, it has become possible to successfully transplant individual intra-abdominal viscera or combinations of these organs. The consequences have been, first, new information about the metabolic interrelations that the visceral organs have in disease or health; second, the addition of several procedures to the treatment armamentarium of gastrointestinal diseases; and third, a more profound understanding of the means by which all whole organ grafts are accepted. © 1993
The "privileged" liver and hepatic tolerogenicity.
The mechanism underlying the immunological advantage of hepatic allografts relative to other organs is incompletely understood. We used molecular probes for the repetitive units on the Y chromosome, to identify an increasing number of male liver venous endothelial cells in needle biopsy samples of men who received female donor liver grafts. We have also shown repopulation of liver endothelium by bone marrow derived cells in a male to female mouse bone marrow transplant model. We conclude that the liver has unique venous endothelium characterized by turnover and replacement by bone marrow derived cells
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