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Biomedical subjects

L Orr

Publications and source records attributed to L Orr.

12 recordsLinked to original sources
PubMed2001

Photosynthesis and the web: 2001.

First, a brief history of the Internet and the World Wide Web is presented. This is followed by relevant information on photosynthesis-related web sites grouped into several categories: (1) large group sites, (2) comprehensive overview sites, (3) specific subject sites, (4) individual researcher sites, (5) kindergarten through high school (K-12) educational sites, (6) books and journals, and, 7) other useful sites. A section on searching the Web is also included. Finally, we have included an appendix with all of the web sites discussed herein as well as other web sites that space did not allow. Readers are requested to send comments, corrections and additions to gov@uiuc.edu.

Journal Article↗
PubMed2001

Use of the skeletal survey in the evaluation of child maltreatment.

The radiologic skeletal survey is an important tool for evaluating occult trauma in suspected child abuse. The purposes of this study were: (1) to determine the incidence of clinically unsuspected fractures detected by skeletal survey, and (2) to identify high-risk groups of children who would benefit from skeletal surveys. We retrospectively reviewed the medical records of 203 children admitted over a 30-month period to Children's National Medical Center for alleged physical abuse. Skeletal surveys were ordered based on the treating physicians' clinical suspicions. Patients in whom skeletal surveys were positive for an occult fracture were studied in more detail. There were 96 skeletal surveys performed; of these, 25 were positive for at least 1 clinically unsuspected fracture. Eighty percent of occult fractures were found in children younger than 1 year old. Presenting with a new fracture or an intracranial injury placed the child at higher risk of occult fracture. In contrast, patients with burn injuries had a very low yield of occult fractures. The patient's age and type of suspicious injury can help guide the physician as to when to obtain a skeletal survey.

Adolescent↗
PubMed1988

Hispanic and black American adolescents' beliefs relating to sexuality and contraception.

Popular beliefs and level of scientific knowledge regarding sexuality and contraception were elicited from black and Hispanic inner-city adolescents. Significant differences were found: Hispanic males were the most knowledgeable, Hispanic females the least, and black males and females were intermediate. A cultural basis for the dramatic difference between Hispanic male and female scores is suggested and the need to design culturally appropriate sexuality education classes is discussed. In addition, the data depicted two conflicting beliefs that were held simultaneously by many of the adolescents: Contraception is "good" because it prevents pregnancy, and it is "bad" because the various birth control methods carry serious health hazards for users.

Adolescent↗
PubMed1987

Vesicle formation during reticulocyte maturation. Association of plasma membrane activities with released vesicles (exosomes).

Vesicles are released during the in vitro culture of sheep reticulocytes which can be harvested by centrifugation at 100,000 X g for 90 min. These vesicles contain a number of activities, characteristic of the reticulocyte plasma membrane, which are known to diminish or disappear upon reticulocyte maturation. The activities include acetylcholinesterase, cytochalasin B binding (glucose transporter) nucleoside binding (i.e. nucleoside transporter), Na+-independent amino acid transport, and the transferrin receptor. Enzymes of cytosolic origin are not detectable or are present at low activity in the vesicles. Cultures of whole blood, mature red cells, or white cells do not yield comparable levels of these activities, supporting the conclusion that the activities arise from the reticulocytes. In addition, the lipid composition of the vesicles shows the high sphingomyelin content characteristic of sheep red cell plasma membranes, but not white cell or platelet membranes, also consistent with the conclusion that the vesicles are of reticulocyte origin. It is suggested that vesicle externalization may be a mechanism for shedding of specific membrane functions which are known to diminish during maturation of reticulocytes to erythrocytes.

Acetylcholinesterase↗
PubMed1987

Externalization of membrane-bound activities during sheep reticulocyte maturation is temperature and ATP dependent.

During the maturation of sheep reticulocytes in vitro, there is release of material that can be pelleted from the cell-free incubation medium by centrifugation at 100,000 X g. This pellet contains activities that are derived from both the plasma membrane and lysosomes. No evidence was obtained for the presence of mitochondrial activities or cytosolic enzyme activities. The release of these activities is ATP and temperature dependent, since reduction of either results in a greater retention of the activities by the cells and a lesser amount in the 100,000 X g pellet. The pelleted material is vesicular in nature, and the production and (or) release of the material are reduced upon ATP depletion or lowering of the temperature. It is concluded that the externalization of specific membrane components is a normal metabolic process that occurs during reticulocyte maturation and represents a means by which reticulocytes shed specific types of membrane-associated functions that are known to decrease during reticulocytes maturation.

Adenosine Triphosphate↗