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Biomedical subjects

L L Barton

Publications and source records attributed to L L Barton.

At least 73 records · Page 4Linked to original sources
PubMed1993

Environmental scanning electron microscope (ESEM) evaluation of crystal and plaque formation associated with biocorrosion.

The biofilm attributed to Desulfovibrio vulgaris growing in the presence of ferrous metals was examined with an environmental scanning electron microscope. This novel microscope produced images of iron sulfide colloids and other iron containing structures that had not been reported previously. A plaque composed of iron sulfide enveloped the surface of the corroding metal while crystals containing magnesium, iron, sulfur, and phosphorus were present in the culture where corrosion was in progress. A structure resembling the tubercule found in aerobic corrosion was observed on stainless steel undergoing biocorrosion and the elements present in this structure included sulfur, iron, chloride, calcium, potassium, and chromium.

Biodegradation, Environmental↗
PubMed1993

Neonatal group B streptococcal cellulitis-adenitis.

A 38-day-old prematurely born infant developed rapidly progressive facial cellulitis in association with ipsilateral submandibular lymphadenopathy and pulmonary consolidation. Group B streptococci (GBS) were isolated from blood, endotracheal, and lesion cultures. Prompt recognition of GBS cellulitis-adenitis and institution of parenteral, synergistic antibiotic therapy are important.

Ampicillin↗
PubMed1993

Ehrlichia chaffeensis and Rochalimaea antibodies in Kawasaki disease.

Sera from 38 patients with Kawasaki disease were tested for immunofluorescent antibodies to Ehrlichia chaffeensis, Rochalimaea henselae, and R. quintana Oklahoma. Only 2.5% of the patients tested positive for E. chaffeensis, and 5% were positive for R. henselae and R. quintana Oklahoma. Our data suggest that Ehrlichia and Rochalimaea spp. do not play a unique role in the etiology of Kawasaki disease.

Antibodies, Bacterial↗
PubMed1993

Respiratory syncytial virus-associated lower respiratory illnesses: possible influence of other agents. The Group Health Medical Associates.

Acute lower respiratory illnesses were prospectively investigated in a cohort of 1246 healthy infants who were enrolled at birth in the Tucson Children's Respiratory Study and followed through the first 3 years of life. Respiratory syncytial virus (RSV) infection was documented by culture, antigen detection or both in 276 episodes. In 21 (7.6%) of these 276, other viruses were simultaneously detected. Further serologic studies of 50 episodes in which RSV had been found increased the apparent viral codetection rate to 24%. When culture results for Chlamydia trachomatis and Mycoplasma pneumoniae were also considered, the rate of codetection was found to be 10.9% (30 of 276); this increased to 28% for the subgroup of episodes (14 of 50) that was further studied serologically. Illnesses associated with more than one agent were not significantly different from those involving RSV alone, with respect to month of onset, age at illness, illness type or duration of illness. We conclude that when RSV has been detected in previously healthy infants, routine searches for the concomitant presence of other viruses are usually not warranted.

Child, Preschool↗
PubMed1992

Suppurative group A beta-hemolytic streptococcal infections in children.

Group A beta-hemolytic streptococci (GABHS) have once again become an important cause of serious suppurative disease in children. A 100% increase in the rate of GABHS bacteremia and an increased frequency in GABHS bacteremia in previously healthy children were observed in 1989 through 1990 compared with 1984 to 1988. Streptococcal isolates were characterized and patient demographic data were tabulated from children hospitalized with GABHS suppurative infections in 1989 through 1990. The differences in clinical manifestations and strains of GABHS were examined in patients with bacteremia, with or without focal site of infection, and in those with focal infections without bacteremia. Bacteremic children were significantly younger and had higher white blood cell counts at admission. No patient had a toxic shock-like syndrome. Although no specific strain was associated with suppurative infections, serum opacity reaction-negative organisms were more frequently associated with focal infections without bacteremia. The data suggest that GABHS may have become more virulent. Physicians should consider GABHS as an important cause of serious suppurative infection in children.

Age Factors↗
PubMed1991

Effects of iron(III) analogs on growth and pseudobactin synthesis in a chromiumtolerant Pseudomonas isolate.

The growth and siderophore production of a fluorescent Pseudomonas species isolated from soil contaminated with chromium was found to be influenced by the presence of trivalent cations. Overproduction of pseudobactin occurred when the isolate was grown in media containing 1 mM Cr(III) under iron-limited conditions but not when Fe(III) was added at 10 microM. Pseudobactin synthesis was derepressed in iron-limited cultures containing 1 mM Sc(III) or Y(III), examples of group III-B elements. We found that Al(III), Ga(III) or In(III), representative metals from group III-A, repressed synthesis of pseudobactin under iron-deficient conditions. Analogs of Fe(III) were found to inhibit growth of the Pseudomonas isolate in iron-limited media and the trivalent metals listed in order of decreasing toxicity were as follows: Ga greater than In greater than Sc greater than Cr greater than Y greater than Al. The inhibition of growth by 1 mM In(III), Sc(III) and Ga(III) was greater during iron-limited growth than in media containing 10 microM Fe(III). These data show that, although the metal analogs of Fe(III) have similar chemical and physical characteristics, the physiological response of the fluorescent pseudomonad when grown in the presence of these metals varied markedly.

Chromium↗
PubMed1991

The influence of preschool pertussis immunization on an epidemic of pertussis.

Between 1988 and 1989 there were 896 reported cases of pertussis in Arizona. Of the 781 investigated cases 55 were identified in children younger than 5 years of age. Thirty-five percent of children between 6 months and 5 years of age were not fully immunized; 3 infants died. Approximately 50% of infected children between 5 and 14 years of age had not received 5 doses of pertussis vaccine. Of the 413 physician respondents to a questionnaire, fully 10% do not administer pertussis vaccine to preschool children because of parental, personal or other reasons. We hypothesize that the reservoir of pertussis-susceptible older children and young adults is augmented by this omission of the fifth diphtheria-tetanus toxoids-pertussis vaccine. Newer educational and vaccine strategies are necessary to prevent epidemics of pertussis.

Adolescent↗