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Articles 151 - 163 of 163

Full-Text Articles in Life Sciences

Recombinant Human Bone Morphogenetic Protein-2 And Collagen For Bone Regeneration, Jeffrey O. Hollinger, John M. Schmitt, David C. Buck, Robert Shannon, Seong-Pil Joh, H Daniel Zegzula, John Wozney Jan 1998

Recombinant Human Bone Morphogenetic Protein-2 And Collagen For Bone Regeneration, Jeffrey O. Hollinger, John M. Schmitt, David C. Buck, Robert Shannon, Seong-Pil Joh, H Daniel Zegzula, John Wozney

Faculty Publications - Department of Biological & Molecular Science

The study reported describes a combination of recombinant human bone morphogenetic protein-2 (rhBMP-2) and collagen (C) to regenerate bone. Unilateral critical-sized defects (CSDs) were prepared in radii of 32 skeletally mature New Zealand white rabbits. Rabbits were divided evenly among four treatments: autograft, absorbable C (Helistatt), 35 mg of rhBMP-2 combined with absorbable C (rhBMP-2/C), and untreated CSDs. The two euthanasia periods were 4 and 8 weeks. Radiographs were taken the day of surgery, every 2 weeks, and at term and the percent of radiopacity was measured. Data analysis revealed a time-dependent increase in the percent radiopacity with rhBMP-2/C. Histological …


Charged Beads Enhance Cutaneous Wound Healing In Rhesus Non-Human Primates, Elisa Burgess, Jeffrey Hollinger, Steven Bennett, John M. Schmitt, Dave Buck, Robert Shannon, Seong-Pill Joh, Jaghu Choi, Thomas Mustoe, Xuanhan Lin, Walter Skalla, Dave Connors, Chris Chrisoforou, Elliott Gruskin Jan 1998

Charged Beads Enhance Cutaneous Wound Healing In Rhesus Non-Human Primates, Elisa Burgess, Jeffrey Hollinger, Steven Bennett, John M. Schmitt, Dave Buck, Robert Shannon, Seong-Pill Joh, Jaghu Choi, Thomas Mustoe, Xuanhan Lin, Walter Skalla, Dave Connors, Chris Chrisoforou, Elliott Gruskin

Faculty Publications - Department of Biological & Molecular Science

Enhanced cutaneous wound healing by positively charged cross-linked diethylaminoethyl dextran beads (CLOD) was studied in a standardized incisional wound model in 20 adult and 20 geriatric 111acaca mulatta (rhesus) partitioned equally over five time periods. Physiologic saline served as a control. Soft-tissue linear incisions were prepared between and l cm inferior to the scapulae. There were four incisions per rhesus; each incision was 1.5 cm long with 1 cm of undisturbed tissue between incisions, and both the experimental CLDD and physiologic saline treatments were administered to each rhesus. The incision treatments were either CLDD and soft-tissue closure with 4-0 BioSyn …


Characterization Of A Basolateral Electroneutral Na+/H+ Antiporter In Atlantic Lobster (Homarus Americanus) Hepatopancreatic Epithelial Vesicles, Jeff Duerr, Gregory A. Ahearn Jan 1996

Characterization Of A Basolateral Electroneutral Na+/H+ Antiporter In Atlantic Lobster (Homarus Americanus) Hepatopancreatic Epithelial Vesicles, Jeff Duerr, Gregory A. Ahearn

Faculty Publications - Department of Biological & Molecular Science

Purified basolateral membrane vesicles (BLMVs) were prepared from Atlantic lobster (Homarus americanus) hepatopancreas using a Percoll density gradient technique. Enrichments of the Na+/K+-ATPase and alkaline phosphatase activities of these vesicles were 15.4- and 1.2- fold, respectively. The presence of amiloride-sensitive Na+/H+ exchange was demonstrated. Contrary to electrogenic 2Na+/1H+ exchange on apical membranes from the same tissue, kinetic studies of Na+ transport by these basolateral membranes indicate an electroneutral antiport with a Km of 28±1.7 mmol l21 and a Jmax of 1.74±0.13 mmol mg21 min21. Amiloride interacted at a single binding site (Ki=39mmol l21) and external Li+ was shown to be …


Ca2+ And Zn2+ Are Transported By The Electrogenic 2na+/1h+ Antiporter In Echinoderm Gastrointestinal Epithelium, Zhenpeng Zhuang, Jeff Duerr, Gregory A. Ahearn Jan 1995

Ca2+ And Zn2+ Are Transported By The Electrogenic 2na+/1h+ Antiporter In Echinoderm Gastrointestinal Epithelium, Zhenpeng Zhuang, Jeff Duerr, Gregory A. Ahearn

Faculty Publications - Department of Biological & Molecular Science

45Ca2+ uptake by purified brush-border membrane vesicles of starfish (Pycnopodia helianthoides) pyloric ceca was stimulated by an outwardly directed H+ gradient and this stimulation was enhanced by the simultaneous presence of an induced membrane potential (inside negative; K+/valinomycin). External amiloride (competitive inhibitor; Ki=660mmol l21) and a monoclonal antibody raised against proteins associated with the lobster (Homarus americanus) electrogenic 2Na+/1H+ antiporter both inhibited approximately half of the proton-gradient stimulated 45Ca2+ uptake. These results suggested that Ca2+ might be transported by the electrogenic antiporter and that the crustacean antibody was inhibitory to the exchange function in echinoderms, as was recently shown in …


Role Of The Invertebrate Electrogenic 2na+/H+ Antiporter In Monovalent And Divalent Cation Transport, Gregory A. Ahearn, Jeff Duerr, V. Pennington Jan 1994

Role Of The Invertebrate Electrogenic 2na+/H+ Antiporter In Monovalent And Divalent Cation Transport, Gregory A. Ahearn, Jeff Duerr, V. Pennington

Faculty Publications - Department of Biological & Molecular Science

In recent years, an electrogenic 2Na+/1H+ antiporter has been identified in a variety of invertebrate epithelial brush-border membranes of gut, kidney and gill tissues. The antiporter differs significantly in its physiological properties from the electroneutral 1Na+/1H+ antiporter proposed for vertebrate cells. In all invertebrate cells examined, the antiporter displayed a 2:1 transport stoichiometry, responded to an induced transmembrane potential and exhibited a high binding affinity for the divalent cation Ca2+, which acted as a competitive inhibitor of Na+ transport. A monoclonal antibody specific for the crustacean electrogenic antiporter inhibited 2Na+/1H+ exchange, but was without effect on Na+-dependent D-glucose transport. Immunoreactivity …


The Effect Of Food Availability On Time And Energy Expenditures Of Territorial And Non-Territorial Hummingbirds, Donald R. Powers, Todd Mckee Jan 1994

The Effect Of Food Availability On Time And Energy Expenditures Of Territorial And Non-Territorial Hummingbirds, Donald R. Powers, Todd Mckee

Faculty Publications - Department of Biological & Molecular Science

We studied the time and energy allocations related to territorial behavior in male Blue-throated Hummingbirds (Lampornis clemenciae; about 8.3 g) under conditions of unlimited and restricted food availability. When food was unlimited. territorial males avoided inter-specific aggression, chasing only 11% of the inter-specific intruders (Black-chinned Hummingbirds, Archilochus alexandri; about 3.5 g). Thus, when food was unlimited, inter-specific intruders were able to forage efficiently, meeting their estimated daily energy requirement with ease (27 kJ/day). Conversely, 81% of intraspecific intruders were chased, and intra-specific intruders were able to feed at territorial feeders only when the territorial male was away. Chases of …


Field Metabolic Rate And Food Consumption Of Two Sympatric Hummingbird Species In Southeastern Arizona, Donald R. Powers, Timothy M. Conley Jan 1994

Field Metabolic Rate And Food Consumption Of Two Sympatric Hummingbird Species In Southeastern Arizona, Donald R. Powers, Timothy M. Conley

Faculty Publications - Department of Biological & Molecular Science

We compared the field metabolic rate (FMR) and behavior around sugar-water feeders of sympatric territorial and non-territorial hummingbirds in the Chiricahua Mountains of southeastern Arizona during July 1987 and 1989. The territorial species was the Blue-throated Hummingbird (Lampornis clemenciae; mean mass 8.77 g) and the non-territorial species the Black-chinned Hummingbird( Archilochusa lexandri; mean mass 3.67 g). FMR (CO2p roduction)a nd watert urnoverw erem easuredu singt he doublyl abeledw ater technique. FMR averaged 81.7 kJ/day (n = 4) in L. clemenciae and 29.1 kJ/day (n = 4) in A. alexandri. Mean mass-specific FMR was higher in L. clemenciae (18.36 ml CO2 …


Synthesis, Structure, And Properties Of The Organic Conductor (Bedt-Ttf)2br2secn, Urs Geiser, H. Hau Wang, John A. Schlueter, Jack M. Williams, James L. Smart, Alan C. Cooper, S. Kalyan Kumar, Maria Caleca, James D. Dudek, K. Douglas Carlson, J. Ren, M. H. Whangbo, J. E. Schirber, W. R. Bayless Jan 1994

Synthesis, Structure, And Properties Of The Organic Conductor (Bedt-Ttf)2br2secn, Urs Geiser, H. Hau Wang, John A. Schlueter, Jack M. Williams, James L. Smart, Alan C. Cooper, S. Kalyan Kumar, Maria Caleca, James D. Dudek, K. Douglas Carlson, J. Ren, M. H. Whangbo, J. E. Schirber, W. R. Bayless

Faculty Publications - Department of Biological & Molecular Science

No abstract provided.


Effect Of Temperature And Humidity On Evaporative Water Loss In Anna's Hummingbird (Calypte Anna), Donald R. Powers Jan 1992

Effect Of Temperature And Humidity On Evaporative Water Loss In Anna's Hummingbird (Calypte Anna), Donald R. Powers

Faculty Publications - Department of Biological & Molecular Science

Evaporative water loss (EWL), oxygen concumption (V0 ), and body temperature (Tb) of Anna's 2 Hummingbirds (Calypte anna; ca. 4.5 g) were measured at combinations of ambient temperature (T J and water vapor density (Qva) ranging from 20 to 37 °C and 2 to 27 g · m-3 , respectively. The EWL decreased linearly with increasing eva at all temperatures. The slopes ofleast squares regression lines relating EWL to Qva at different temperatures were not significantly different and averaged -0.50mg H20·m-3 ·g-2 ·h-1 (range: -0.39 to -0.61). Increased Qva restricted EWL in C. anna more than has been reported for …


Diurnal Variation In Mass, Metabolic Rate, And Respiratory Quotient In Anna's And Costa's Hummingbirds, Donald R. Powers Jan 1991

Diurnal Variation In Mass, Metabolic Rate, And Respiratory Quotient In Anna's And Costa's Hummingbirds, Donald R. Powers

Faculty Publications - Department of Biological & Molecular Science

To examine how hummingbirds that do not enter torpor at night store and utilize energy, open-circuit respirometry and a strain gauge were used to measure daily variation in 0 2 consumption (Vo2 ), C02 production, respiratory quotient (RQ), and body mass in Anna's hummingbird, Calypte anna, and Costa's hummingbird, Calypte costae. During the day, Vo2 was highly variable primarily because of dif ferences in activity among individuals. At night Vo2 varied little between individuals, but mean Vo2 was more than two times that predicted from body mass for resting, postabsorptive birds. F0.85), indicating the use of carbohydrate as a …


Osmotic Effects On Mitochondria From Two Species Of Amphibian, Bufo Marinus And Rana Catesbeiana, Jeff Duerr Jan 1991

Osmotic Effects On Mitochondria From Two Species Of Amphibian, Bufo Marinus And Rana Catesbeiana, Jeff Duerr

Faculty Publications - Department of Biological & Molecular Science

The effects ql ionic and/or osmotic change on skeletal muscle mitochondrial performance were investigated. Two substrates, pyruvate and glutamate, and variation in osmotic pressure from 205 to 360 mosm in KCl or mannitol/sucrose media had no effect on maximal respiratory rate (state 3) or coupling (respiratory control ratio) in either species. Over an equivalent range of osmolalities associated with dehydration, organismic maximal 02-consumption rates are severely diminished with increasing osmolalities. The data do not support a mitochondria/limit to organismic 02 consumption under dehydration. There were interspecies differences in state 3 respiration and coupling that were similar to differences noted in …


Field Metabolic Rate And Food Consumption By Free-Living Anna's Hummingbirds (Calypte Anna), Donald R. Powers, Kenneth A. Nagy Jan 1988

Field Metabolic Rate And Food Consumption By Free-Living Anna's Hummingbirds (Calypte Anna), Donald R. Powers, Kenneth A. Nagy

Faculty Publications - Department of Biological & Molecular Science

We measured C02 production and water flux using doubly labeled water in wild Anna's hummingbirds living in the Santa Ana Mountains of Southern California during autumn (September) of 1981. The estimated field metabolic rate (FMR) of a hummingbird maintaining a constant body mass (mean 4.48 g) is about 32 kl/day, which is 5.2 times basal metabolic rate (BMR). Metabolic rates during daylight hours were about 6.8 X BMR, less than one-half that expected for an Anna's hummingbird in continuous hovering flight. We estimated nighttime metabolism to be near 2.1 X BMR, which is about what would be expected for a …


Effects Of Variation In Food Quality On The Breeding Territoriality Of The Male Anna's Hummindbird, Donald R. Powers Jan 1987

Effects Of Variation In Food Quality On The Breeding Territoriality Of The Male Anna's Hummindbird, Donald R. Powers

Faculty Publications - Department of Biological & Molecular Science

Thirteen territorial male Anna’s Hummingbirds, Calypte anna, were observed during the 1981 and 1982 breeding seasons. Breeding territories were large, but size was not determined by energy availability. When a food source (sucrose solution in feeders) was present, the degree to which it was defended was a function of food quality. If a high-quality food source was absent, males did not exhibit the behaviors associated with defending a food source, but breeding territoriality remained intact. Territories were maintained for the entire breeding season even when food quality was varied. The lack of a relationship between the number of chases involving …