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Biomedical subjects

L L Barton

Publications and source records attributed to L L Barton.

At least 109 records · Page 6Linked to original sources
PubMed1988

Intussusception associated with transient hypertension.

A three-month-old infant presented with vomiting, lethargy, and hypertension. Abdominal ultrasound suggested the diagnosis of intussusception, which was confirmed by barium enema. Hypertension, previously unreported with intussusception, only resolved after surgical resection of the lesion.

Barium Sulfate↗
PubMed1988

Influence of oxygen tension on the respiratory activity of Mycobacterium phlei.

Growth of Mycobacterium phlei under low oxygen tension resulted in specific activities two to twenty times lower for formate dehydrogenase, malate dehydrogenase, beta-hydroxybutyrate dehydrogenase, lactate oxidase and NADH dehydrogenase than when cultures were grown under high aeration. An increase in fumarate reductase and succinate dehydrogenase occurred with M. phlei grown under low oxygen tension. Malate: vitamin K dehydrogenase and glucose-6-phosphate dehydrogenase activity were not significantly affected by the oxygen tension used to grow the bacteria, and neither culture contained a lactate dehydrogenase. With growth of M. phlei in conditions of low oxygen tension, cytochrome a was not detected, but cytochrome b was prominent in membranes and cytochrome c was present in the soluble fraction.

Aerobiosis↗
PubMed1988

Impetigo contagiosa: a comparison of erythromycin and dicloxacillin therapy.

One hundred patients with impetigo were prospectively enrolled in a study to determine the current etiology and comparative therapeutic efficacy of two oral antimicrobial agents active against both group A beta-hemolytic streptococci (GABS) and Staphylococcus aureus. After obtaining a bacterial culture from a representative impetiginous lesion, the children were randomized to receive 10 days of either erythromycin (40 mg/kg/day) or dicloxacillin (25 mg/kg/day). S. aureus alone was isolated from 46 children, and in association with GABS from 25 children. GABS alone was isolated from nine patients. Of the 59 evaluable children with S. aureus isolates, 28 of 29 treated with erythromycin and 29 of 30 treated with dicloxacillin were cured or improved on follow-up examination. Thus, we conclude that erythromycin is the drug of choice for impetigo in our midwestern locale because of its high efficacy and relatively low cost.

Adolescent↗
PubMed1988

Fluorescein Isothiocyanate-Labeled Lectin Analysis of the Surface of the Nitrogen-Fixing Bacterium Azospirillum brasilense by Flow Cytometry.

The cell surface of Azospirillum brasilense was probed by using fluorescein isothiocyanate (FITC)-labeled lectins, with binding determined by fluorescence-activated flow cytometry. Cells from nitrogen-fixing or ammonium-assimilating cultures reacted similarly to FITC-labeled lectins, with lectin binding in the following order: Griffonia simplicifolia II agglutinin > Griffonia simplicifolia I agglutinin > Triticum vulgaris agglutinin > Glycine max agglutinin > Canavalia ensiformis agglutinin > Limax flavus agglutinin > Lotus tetragonolobus agglutinin. The fluorescence intensity of cells labeled with FITC-labeled G. simplicifolia I, C. ensiformis, T. vulgaris, and G. max agglutinins was influenced by lectin concentration. Flow cytometry measurements of lectin binding to cells was consistent with measurements of agglutination resulting from lectin-cell interaction. Capsules surrounding nitrogen-fixing and ammonium-assimilating cells were readily demonstrated by light and transmission electron microscopies.

Journal Article↗
PubMed1987

Septic arthritis in childhood. A 13-year review.

Medical records of 111 children discharged with the diagnosis of septic arthritis from 1973 through 1985 were examined; 122 infected joints were identified. Bacteria were isolated from joint fluid of 75 patients and from blood, cerebrospinal fluid, cervix, bone, or wounds of 16. No agent was isolated from 20 patients, of whom eight had been pretreated with antibiotics. The knee and hip were most often affected overall (73/122), although the ankle was as frequently involved with Haemophilus influenzae type b (6/20). Eighty patients' condition resolved with no sequelae; 18 were unavailable for follow-up. Of the 13 patients with permanent sequelae, ten had had hip joint infections. Although Staphylococcus aureus was isolated from patients of all ages, H influenzae type b was the most frequent pathogen in children 6 through 59 months of age.

Adolescent↗
PubMed1987

Impetigo: a reassessment of etiology and therapy.

Traditional concepts regarding the bacteriology and therapy of nonbullous impetigo have been reexamined. Although in the United States the disease is considered primarily of streptococcal origin and amenable to penicillin therapy, we found that Staphylococcus aureus was the most common isolate in 71 patients studied. Only two patients yielded pure cultures of group A beta-hemolytic streptococci. All but two isolates of S. aureus were resistant to penicillin; one of these two isolates was also resistant to erythromycin. Erythromycin appeared to be more efficacious than penicillin for the treatment of impetigo.

Child, Preschool↗
PubMed1987

Purification and properties of protoporphyrinogen oxidase from an anaerobic bacterium, Desulfovibrio gigas.

Protoporphyrinogen oxidase has been solubilized from plasma membranes of Desulfovibrio gigas. The enzyme was purified to apparent homogeneity with single silver-stained protein bands on isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gels. This protoporphyrinogen oxidase has a molecular weight (Mr) of 148,000 and is composed of three dissimilar subunits of Mrs 12,000, 18,500, and 57,000, which are held together by sulfhydryl bonds. Unlike other protoporphyrinogen oxidases, which use molecular oxygen as an electron acceptor, this enzyme does not couple to oxygen. The protoporphyrinogen oxidase donates electrons to 2,6-dichlorophenol-indophenol but not to NAD+, NADP+, flavin adenine dinucleotide, or flavin mononucleotide. The natural physiological electron acceptor of the protoporphyrinogen oxidase from D. gigas is unknown. By using 2,6-dichlorophenol-indophenol as the electron acceptor, the Km and Vmax values for oxidation of protoporphyrinogen were determined to be 21 microM and 8.38 nmol/min per 70 micrograms of protein, respectively. The catalytic rate constant, Kcat, was calculated to be 17.7 mol of protoporphyrin formed per mole of enzyme per min of incubation, and the Kcat/Km was 0.84. Energies of activation were calculated from Arrhenius plots with 7,429 cal (ca. 31,080 J)/mol per degree below 10 degrees C and 1,455 cal (ca. 6,088, J)/mol per degree above 10 degrees C. Optimum enzyme activity was at 23 degrees C, and inhibition was observed with both N-ethylmaleimide and iodoacetamide.

Anaerobiosis↗
PubMed1986

Phenotypic changes in mycobacteria grown in oxygen-limited conditions.

Laboratory strains of Mycobacterium phlei, M. smegmatis, M. fortuitum, M. gordonae, M. kansasi, M. bovis, M. tuberculosis and M. intracellulare were adapted to grow in an anaerobic environment. Concomitant with the transition to anaerobic growth was loss of acid-fastness, loss or modification of colonial pigmentation, and loss of ability to grow on a malachite green-containing medium. The mycobacteria grown anaerobically produced acid from a greater range of carbohydrates than aerobically grown cultures, lost iron-uptake activity, and showed a reduction of urease, catalase and nitratase activity. Back adaption of mycobacteria from an anaerobic to an aerobic environment resulted in the acquisition of acid-fastness, pigmentation, and other characteristics used in the taxonomy of mycobacteria. These results suggest that mycobacterial cultures, if grown in an anaerobic environment, may be erroneously identified in clinical laboratories.

Adaptation, Physiological↗
PubMed1986

Discoid lupus erythematosus and X-linked chronic granulomatous disease.

X-linked chronic granulomatous disease (CGD), a defect of leukocyte bactericidal capacity, was seen in three generations of a large kindred. The association of discoid lupus erythematosus (DLE) with CGD was noted. Recurrent antigenic stimulation leading to autoantibody formation may explain the apparently increased frequency of DLE in female carriers of CGD. A screen for CGD, the nitroblue tetrazolium test, is suggested for females with DLE who have experienced suppurative infections or who have a family history of early childhood deaths or recurrent infections.

Adult↗
PubMed1986

Neonatal septicemia due to Pseudomonas aeruginosa.

Group B streptococci and Escherichia coli are the most frequently isolated etiologic agents in neonatal septicemia. Neonatal infection that is caused by Pseudomonas aeruginosa is usually late in onset, nosocomial in origin and epidemic in pattern. However, P. aeruginosa must be considered in all neonatal infections, regardless of the age of onset, so that early, appropriate and often lifesaving antibiotic therapy may be instituted.

Adult↗
PubMed1985

Oxidation of protoporphyrinogen in the obligate anaerobe Desulfovibrio gigas.

The anaerobic oxidation of protoporphyrinogen to protoporphyrin was demonstrated in extracts of Desulfovibrio gigas. Protoporphyrin formation occurred in the presence of nitrite, hydroxylamine, sulfite, thiosulfate, ATP plus sulfate, NAD+, NADP+, flavin adenine dinucleotide, flavin mononucleotide, fumarate, 2,6-dichlorophenol-indophenol, methyl viologen, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. With dialyzed cell extracts, highest activities were observed with sulfite, NAD+, and NADP+ as electron acceptors. The enzyme for protoporphyrinogen oxidation was localized in the membrane of D. gigas and displayed optimal activity at pH 7.3 and 28 degrees C.

Desulfovibrio↗