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Biomedical subjects

D K Smith

Publications and source records attributed to D K Smith.

At least 127 records · Page 7Linked to original sources
PubMed1982

Antimicrobial resistance among Pasteurella spp recovered from Missouri and Iowa cattle with bovine respiratory disease complex.

A retrospective study was conducted to determine the prevalence of antimicrobial resistance among Pasteurella spp recovered from cattle with bovine respiratory disease complex. The study extended from January 1976 through May 1980, and included a review of the necropsy records of 386 beef cattle. Susceptibility or resistance of the Pasteurella isolants was determined by using the standard disk diffusion susceptibility test. Each isolant was tested for susceptibility with 15 different antimicrobial agents. A high prevalence of resistance (greater than 80%) was found when Pasteurella was tested with triple sulfonamides. For P haemolytica isolants, 57% to 70% were resistant to ampicillin (56/97), penicillin (58/101), and streptomycin (70/100); for unidentified Pasteurella spp isolants, 64% to 91% were resistant to ampicillin (83/129), penicillin (89/129), and streptomycin (118/129). For P haemolytica (21/100) and P multocida (34/146) isolants, 21% to 23% were resistant to tetracycline. Most of the P multocida isolants did not show marked antimicrobial resistance to 9 of the 15 drugs tested. However, 58% of the P multocida isolants (84/145) were resistant to streptomycin and 88% of them were resistant to three combined sulfonamides (126/144).

Animals↗
PubMed1981

Effects of activated carbon and bacteriostatic filters on microbiological quality of drinking water.

Three activated carbon filters for point-of-use water treatment were tested in laboratory and field studies for chemical removal and microbiological effects on water. All removed free available chlorine in municipally treated water to below the limit of detection, but removed only about 50 to 70% of the total available chlorine and 4 to 33% of the total organic carbon. Standard plate count bacteria in the effluent increased steadily with time for 3 weeks and remained elevated over the 8-week period of the study. Total coliform bacteria were found to persist and proliferate on the filters for several days after transient contamination of the influent water. Silver-containing activated carbon filters suppressed total coliform but not total bacterial growth. Pseudomonas aeruginosa was recovered from the effluents of all filters at some time during the tests.

Bacteria↗
PubMed1980

Clinical pharmacology of intermediate-dose oral methotrexate.

The clinical pharmacology of intermediate-dose oral methotrexate (MTX) was studied in nine patients receiving 18 courses of treatment. Serum and urine MTX concentrations were measured by means of a competitive protein binding assay after oral aqueous solution (3 courses), 50-mg tablets (13 courses) or IV drug (2 courses) had been administered in four doses of 100 mg/m2 at 6-h intervals or in four doses of 200 mg/m2 at 6-h intervals and followed by citrovorum factor rescue. Levels above 150 ng/ml (3.3 x 10(-7) M) were maintained throughout all treatment cycles, with rapid disappearance of drug after the last dose. A 100% increase in administered dose resulted in only a 42% increase in the concentration-time level. Methotrexate was absorbed well from both aqueous solutions and 50-mg tablets, but serum levels after 50-mg tablets were only 20% of those achieved after IV administration. We conclude that significant serum MTX concentrations can be achieved for prolonged periods of time after oral administration of intermediate doses, but that the proportion of drug absorbed is much less than is seen with lower doses.

Administration, Oral↗
PubMed1980

The occurrence of 1,2-propanediol oxidoreductase in micro-organisms and its use as a possible diagnostic marker for Neisseria gonorrhoeae.

The cervical microbial flora of 25 females and stock cultures of various micro-organisms which may be present in the human female cervix were examined using a fluorimetric assay for 1,2-propanediol oxidoreductase. Results indicated that only members of the genera Neisseria and Acinetobacter possess appreciable activities of the enzyme, whose physiological function is not yet known. The activity of this enzyme in N. gonorrhoeae appeared to be significantly higher than the activities observed in mot of the other Neisseria species and in the Acinetobacter species. These results indicated that it may be possible to utilize this enzyme as a presumptive diagnostic marker for N. gonorrhoeae in cervical secretions. 1,2-Propanediol oxidoreductase may also be of taxonomic significance for the classification of various bacterial species.

Acinetobacter↗
PubMed1980

Radioiodination of an outer membrane protein in intact Rickettsia prowazekii.

Intact Rickettsia prowazekii was radiolabeled with the glucose oxidase-lactoperoxidase method of iodination. Separation of the rickettsial extract into cytoplasmic, outer and inner membrane fractions demonstrated that the outer membrane was preferentially labeled. Analysis of the polypeptides of these fractions on high-resolution slab polyacrylamide gels showed that most of the 125I was in polypeptide T49, an outer membrane constituent. Additional outer membrane polypeptides were iodinated in broken envelope preparations, demonstrating that T49 is uniquely accessible to the external environment and the asymmetric polypeptide organization of the outer membrane.

Autoradiography↗
PubMed1980

Enzymatic detection of Neisseria gonorrhoeae.

In a study using a non-serological enzymatic approach for the detection of Neisseria gonorrhoeae in cervical and urethral swabs, the technique was shown to be technically feasible. The enzyme, 1, 2-propanediol oxidoreductase, was used as a presumptive diagnostic marker for N gonorrhoeae. Enzymatic activity was measured with a fluorometer. Two assay procedures were performed: (a) enzyme detection (two-tube and three-tube assays) requiring 60 minutes; and (b) enzyme inhibition (EI) (90-minute and modified 20-minute assays). Sensitivities of the two-tube, three-tube, and the 90-minute EI assays with male urethral specimens from a high-prevalence population were 80%, 84%, and 91% respectively. The specificities of these assays in a low-prevalence male population were not determined. Sensitivity of the 90-minute EI assay in a high-prevalence female group was 77% and specificity in a low-prevalence female group was 75%. The modified EI assay was tested only in a low-prevalence female group and had 87% specificity. Although the specificity of the assays needs improvement, several advantages--including early case detection, rapid availability of results, detection of current active infections, and the possibility of automation--are intrinsic in this enzymatic approach.

Alcohol Oxidoreductases↗
PubMed1979

Inflammatory fibrous histiocytoma: response to non-surgical therapy: a case report.

A case of inflammatory fibrous histiocytoma arising in soft tissue near the sacrum is presented. The patient's mode of presentation, clinical course, and tumor histology were typical of this disease. The tumor was inoperable, and radiotherapy combined with doxorubicin, cyclophosphamide, and intermediate-dose oral methotrexate produced a dramatic complete response lasting over 27 months. Favorable results with nonsurgical therapy have not previously been reported for this disease. The gratifying result obtained, although of relatively short duration to date, indicates that combined modality therapy may provide significant back-up to aggressive surgery. The use of these agents in an adjuvant setting merits study.

Adult↗
PubMed1979

Separation of inner and outer membranes of Rickettsia prowazeki and characterization of their polypeptide compositions.

Rickettsia prowazeki were disrupted in a French pressure cell and fractionated into soluble (cytoplasm) and envelope fractions. The envelope contained 25% of the cell protein, with the cytoplasm containing 75%. Upon density gradient centrifugation, the envelope fraction separated into a heavy band (1.23 g/cm3) and a lighter band (1.19 g/cm3). The heavy band had a high content of 2-keto-3-deoxyoctulosonic acid, a marker for bacterial lipopolysaccharide, but had no succinic dehydrogenase, a marker for cytoplasmic membrane activity, and therefore represented outer membrane. The lighter band exhibited a high succinate dehydrogenase activity, and thus contained inner (cytoplasmic) membrane. Outer membrane purified by this method was less than 5% contaiminated by cytoplasmic membrane; however, inner membrane from the gradient was as much as 30% contaminated by outer membrane. The protein composition of each cellular fraction was characterized by sodium dodecyl sulfate--polyacrylamide gel electrophoresis. The outer membrane contained four major proteins, which were also major proteins of the whole cell. The cytoplasmic membrane and soluble cytoplasm exhibited a more complex pattern on gels.

Bacterial Proteins↗
PubMed1977

Characterization of a lysine-specific active transport system in Rickettsia prowazeki.

Rickettsia prowazeki possesses an active transport system for lysine with a Kt of influx of 1 muM. Extraction and chromatographic analysis of the accumulated labeled material show the material to be lysine rather than a derivative. This intracellular lysine pool can be exchanged with external unlabeled substrates for at least 10 min; The lysine analogues L-aminoethyl cysteine, N-methyl lysine, hydroxylysine, and D-lysine competitively inhibit uptake of L-lysine, but cadaverine, diaminopimelate, arginine, ornithine, and epsilon-aminocaproate do not. Accumulation of lysine can be inhibited by the energy poisons potassium cyanide, triphenylmethyl phosphonium bromide, and 2,4-dinitrophenol. The effect of potassium cyanide, but not 2,4-dinitrophenol or triphenylmethyl phosphonium bromide, can be overcome by adenosine 5'-triphosphate. Both energy-dependent influx and energy-independent efflux are inhibited by the sulfhydryl reagents N-ethyl maleimide and p-chloromercuriphenyl sulfonic acid.

Adenosine Triphosphate↗
PubMed1974

Bacterial culture longevity: control by inorganic phosphate and temperature.

Death of cells in cultures of six species of gram-negative bacteria was accelerated by incorporation in the medium of 10-fold more inorganic phosphate than was needed for growth. Death induced by inorganic phosphate was independent of the carbohydrate employed and was enhanced by warm temperatures.

Bacteria↗
PubMedDate not supplied

Superior cantholysis for zygomatic fracture repair.

OBJECTIVE: To determine if performing a superior cantholysis eases the surgical exposure, reduction, and rigid fixation of the zygomaticofrontal suture in the open repair of zygomatic complex (ZMC) fractures. PATIENTS AND METHODS: Fifteen superior cantholysis procedures were used in 14 patients who presented with ZMC fractures requiring open reduction and internal fixation. Follow-up ranged from 6 to 18 months. Collected data included patient demographics, cause of fracture, fracture classification, associated facial injuries, methods of fracture exposure and reduction, type and location of fixation, procedure-related complications, and postoperative outcome, including adequacy of fracture reduction. RESULTS: Superior cantholysis opens a direct surgical route to the zygomaticofrontal suture for exposure, reduction, and rigid fixation. It also expedites exposure and assessment of the sphenozygomatic suture. No postreduction ZMC malunions or malpositions occurred during the study. There were 4 complications, none of which could be attributed to superior cantholysis. The complications related primarily to the transconjunctival and lateral canthotomy incisions. CONCLUSIONS: Superior cantholysis eases the surgical exposure, reduction, and rigid fixation of the zygomaticofrontal suture in the open repair of ZMC fractures. The superior cantholysis added no morbidity in open ZMC fracture repair, and it simplified exposure of the lateral orbital rim, without the need for overzealous tissue retraction.

Adolescent↗
PubMedDate not supplied

Radiographic features of hand and wrist arthroplasties.

The normal and abnormal radiographic appearances of various arthroplasties of the hand and wrist have been presented. It is hoped that increased familiarity with these procedures and their radiographic features will lead to more meaningful radiographic interpretations by consulting radiologists.

Finger Joint↗
PubMedDate not supplied

Radiographic features of hand and wrist surgery excluding arthroplasties.

The normal and abnormal radiographic appearances of various hand and wrist surgical procedures have been presented. It is hoped that increased familiarity with these procedures and their radiographic features will lead to more meaningful radiographic interpretations by consulting radiologists.

Arthrodesis↗