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Biomedical subjects

R W Sanders

Publications and source records attributed to R W Sanders.

31 records · Page 2Linked to original sources
PubMed1986

Use of metabolic inhibitors to estimate protozooplankton grazing and bacterial production in a monomictic eutrophic lake with an anaerobic hypolimnion.

Inhibitors of eucaryotes (cycloheximide and amphotericin B) and procaryotes (penicillin and chloramphenicol) were used to estimate bacterivory and bacterial production in a eutrophic lake. Bacterial production appeared to be slightly greater than protozoan grazing in the aerobic waters of Lake Oglethorpe. Use of penicillin and cycloheximide yielded inconsistent results in anaerobic water and in aerobic water when bacterial production was low. Production measured by inhibiting eucaryotes with cycloheximide did not always agree with [H]thymidine estimates or differential filtration methods. Laboratory experiments showed that several common freshwater protozoans continued to swim and ingest bacterium-size latex beads in the presence of the eucaryote inhibitor. Penicillin also affected grazing rates of some ciliates. We recommend that caution and a corroborating method be used when estimating ecologically important parameters with specific inhibitors.

Journal Article↗
PubMed1986

Depth distribution of bacterial production in a stratified lake with an anoxic hypolimnion.

The purpose of this study was to determine the depth distribution of bacterial biomass and production in a stratified lake and to test techniques to measure bacterial production in anaerobic waters. Bacterial abundance and incorporation of both [H]thymidine and [H]leucine into protein were highest in the metalimnion, at the depth at which oxygen first became unmeasurable. In contrast, [H]thymidine incorporation into DNA was highest in the epilimnion. The ratios of incorporation into DNA/protein averaged 2.2, 0.49, and 0.95 for the epilimnion, metalimnion, and hypolimnion, respectively. Low incorporation into DNA was not due to artifacts associated with the DNA isolation procedure. Recovery of added [H]DNA was about 90% in waters in which the portion of [H]thymidine incorporation into DNA was about 40%. At least some obligate anaerobic bacteria were capable of assimilating thymidine since aeration of anaerobic hypolimnion waters substantially inhibited thymidine incorporation. The depth profile of bacterial production estimated from total thymidine and leucine incorporation and the frequency of dividing cells were all similar, with maximal rates in the metalimnion. However, estimates of bacterial production based on frequency of dividing cells and leucine incorporation were usually significantly higher than estimates based on thymidine incorporation (using conversion factors from the literature), especially in anaerobic hypolimnion waters. These data indicate that the thymidine approach must be examined carefully if it is to be applied to aquatic systems with low oxygen concentrations. Our results also indicate that the interface between the aerobic epilimnion and anaerobic hypolimnion is the site of intense bacterial mineralization and biomass production which deserves further study.

Journal Article↗
PubMed1985

The donor profile survey--a way to determine priorities.

Community size, educational background, reading habits, church membership, civic clubs and marital status are just as much a part of why and how much a donor contributes as are his annuity or stock and bond holdings. Learning to profile donors can help set priorities.

Communication↗
PubMedDate not supplied

Radial head fractures associated with elbow dislocations treated by immediate stabilization and early motion.

Twenty-one elbow dislocations with an associated radial head fracture were treated with immediate joint reduction, stabilization, and early range-of-motion exercises. In all cases initial treatment involved closed reduction of the ulnohumeral joint. For those cases involving minimally displaced and a few moderately displaced radial head fractures, treatment consisted of benign neglect (4 of 21). Of the more severely displaced fractures (17 of 21), 9 were treated with open-reduction internal fixation and 8 with immediate silicone head replacement. Despite radial head treatment, 6 of these cases remained unstable, prompting primary repair of collateral ligaments; 3 eventually required application of a hinged fixator as a salvage option. Results confirmed that initial radial head displacement predicts functional outcome. Our study demonstrates that fracture dislocations of the elbow demand a broad consideration of treatment options and that reconstruction of elbow stability requires either primary repair of collateral ligaments or the possible use of a hinged fixator device.

Adolescent↗
PubMedDate not supplied

Characterization of patients with high-energy lower extremity trauma.

PURPOSE: (a) to report the demographic, socioeconomic, behavioral, social, and vocational characteristics of patients enrolled in a study to examine outcomes after high-energy lower extremity trauma (HELET) and to compare them with the general population; (b) to determine whether characteristics of patients undergoing limb salvage versus amputation after HELET are significantly different from each other. DESIGN AND STUDY POPULATION: A prospective study of 601 patients admitted with high-energy lower extremity trauma to eight Level I trauma centers. PROCEDURES: Patients were evaluated during the initial hospitalization. They are being followed up for 24 months postinjury. Study patients are compared with the general population by using census information, population survey data, and published norms. Characteristics of patients undergoing limb salvage versus amputation are also compared. RESULTS: Most patients were male (77 percent), white (72 percent), and between the ages of twenty and forty-five years (71 percent). Seventy percent graduated from high school (compared with 86 percent nationally) (p < 0.05). One fourth lived in households with incomes below the federal poverty line, compared with 16 percent nationally (p < 0.05). The percentage with no health insurance (38 percent) was also higher than in the general population (20 percent) (p < .05). The percentage of heavy drinkers was over two times higher than reported nationally (p < 0.01). Study patients were slightly more neurotic and extroverted and less open to new experiences. When patient characteristics were compared for those undergoing amputation versus limb salvage, no significant differences were found among any of the variables (p > 0.05). CONCLUSION: In conclusion, LEAP patients differ in important ways from the general population. However, the decision to amputate verus reconstruct does not appear to be significantly influenced by patient characteristics.

Adolescent↗
PubMedDate not supplied

Percutaneous plating in the lower extremity.

Since the late 1950s, open reduction and internal fixation has been advocated to restore bone anatomy and enable early mobilization. This approach often necessitated extensive dissection and tissue devitalization, creating an environment less favorable for fracture union and more prone to bone infection. As a result, other methods, such as intramedullary nailing, have become the standard treatment for most diaphyseal fractures of the femur and tibia. However, internal fixation with plates and screws remains the treatment of choice for most periarticular fractures and other complex fractures inadequately stabilized by intramedullary nailing. Recently, more "biologic" methods of reduction involving the use of indirect techniques and new plate designs have been developed in an attempt to preserve the blood supply to the injured bone, improve the rate of fracture healing, decrease the need for bone grafting, and lower the incidence of infection and other complications. Percutaneous plating appears to be the next step in the evolution of biologic plating. With these techniques, the fracture is reduced indirectly, and plates are placed into submuscular or subcutaneous tunnels through limited skin incisions. This may result in less surgical trauma to tissues and further improvements in clinical results compared with current methods of plate insertion.

Bone Plates↗