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Biomedical subjects

A C Anderson

Publications and source records attributed to A C Anderson.

At least 37 records · Page 2Linked to original sources
PubMed1999

Intravenous catheter blood cultures: utility and contamination.

OBJECTIVE: In pediatrics, blood cultures (BCs) are often drawn as intravenous (IV) catheters are placed. This routine minimizes the number of painful and often difficult punctures a child must undergo but results in the discarding of multiple BC bottles when these cultures are later determined to be unnecessary. If the contamination rate of BCs drawn through an indwelling IV did not exceed the contamination rate of BCs drawn at the time of IV placement, BCs could be drawn from the IV without subjecting the patient to another venipuncture. This study was done to compare the contamination rates of BCs drawn by these two methods. Additionally, we sought to determine if the collection of two BCs enhances pathogen recovery. METHODS: Prospective comparison of contamination and bacteremia rates of BCs drawn by two different methods: the first BC was drawn at the time of IV line placement and the second BC was drawn from the previously placed IV at a later time. Setting. Urban pediatric emergency department with an annual census of 40 000. PARTICIPANTS: One thousand five hundred sixty-four patients between the ages of 3 days and 22.1 years. The median age was 2.2 years. Sixty-four patients were excluded because we were unable to draw the second BC. Forty-six percent of eligible patients (n = 690) were girls. RESULTS: Fifty-seven (1.9%) of 3000 grew contaminants: 27 in the first and 30 in the second BC for contamination rates of 1.8% and 2.0%. Thirty-eight (1.3%) of 3000 BCs grew pathogens: 24 represent 12 patients with growth in two out of two cultures and 14 represent 14 patients with growth in one out of two cultures. Pathogen rates were 1.1% (16/1500) with one BC per patient and 1.7% (22/1500) with two BCs per patient. CONCLUSIONS: There is no difference in the contamination rates of two BCs drawn from the same site at two different times. The collection of two BCs per patient may enhance pathogen recovery.

Adolescent↗
PubMed1998

Frozen oral hydration as an alternative to conventional enteral fluids.

BACKGROUND: Oral hydration therapy is effective in dehydration, but is often bypassed or may fail. OBJECTIVE: To compare the tolerance (amount accepted minus amount vomited) of a frozen solution (FS) (Revital-ICE, PTS Labs, Deerfield, Ill) with the conventional glucose electrolyte solution (CS). DESIGN: Prospective, controlled crossover trial. SETTING: Pediatric emergency department. PARTICIPANTS: A convenience sample of 91 children with enteritis, 6 months to 13 years of age, with mild or moderate dehydration. INTERVENTION: Children were offered either FS or CS. Each group was offered 10 mL/kg of either product during a 90-minute trial period, in 3 equal aliquots, and was monitored for the quantities consumed and vomited. Complete treatment failures (absolute refusal) were crossed over to the alternate product and intake was recorded. MAIN OUTCOME MEASURES: Tolerance of the full 10 mL/kg of the original product offered and, for treatment failures, the percentage who tolerated the alternate product. RESULTS: Of the patients who initially received FS, 23 (55%) tolerated the full amount offered, compared with 5 (11%) in the CS group (P < .001). Of the 57% who completely refused CS, after crossover, 20% tolerated the full amount of FS and 33% tolerated between 5 and 9 mL/kg of FS and were discharged from the hospital. The original treatment failures for FS (12%) were crossed over to CS; none tolerated more than 5 mL/kg CONCLUSIONS: Children with mild or moderate dehydration are more likely to tolerate FS than CS. Conventional solution failures crossed over to FS had a greater tolerance rate than the reverse.

Adolescent↗
PubMed1997

The Master of Public Health program for Arkansas.

A unique Master of Public Health (MPH) program has been operating in Arkansas for the past two years. Developed by the faculty of the School of Public Health and Tropical Medicine at Tulane University Medical Center, it offers health professionals the opportunity to earn the MPH degree over a two-year period while remaining in their positions and communities. Most classes are taught on the campus of the University of Arkansas for Medical Sciences (UAMS) in Little Rock. Several courses have been offered by the faculty of the Health Services Administration program and Department of Biology at the University of Arkansas at Little Rock (UALR).

Adult↗
PubMed1996

Sequence variation as a strategy for crystallizing RNA motifs.

The determination of RNA structures by X-ray crystallography is an exciting and developing field. At present, the crystallographic characterization of RNA is limited by the difficulty in obtaining large, high quality crystals. This paper outlines several techniques for improving the likelihood of obtaining RNA crystals, for improving the size of those crystals, and for extending the limit of the diffraction maxima. Sequence variations have proven to be more effective in changing the quality of the crystals than variations in crystallization conditions, often making the difference between obtaining true single crystals and multiply twinned crystalline material.

Base Sequence↗
PubMed1996

HPLC purification of RNA for crystallography and NMR.

Homogeneous preparations of milligram quantities of RNA are a prerequisite for their characterization by biophysical methods such as crystallography or NMR spectroscopy. Methods for obtaining milligram quantities of pure synthetic RNA are described in this paper. These methods employ anion exchange HPLC for purifying full-length sequence from failure sequences and incompletely deprotected material. RNA molecules with little or extensive amounts of secondary structure could be purified. In cases where the RNA molecule was tightly folded, the cation in the eluent buffer influenced both the distinction of the peaks during chromatography and the final folded conformation. Finally, two RNA sequences were chemically synthesized, deprotected, purified, and crystallized using this methodology.

Base Sequence↗
PubMed1996

The expression of human endogenous retrovirus-3 in fetal cardiac tissue and antibodies in congenital heart block.

Endogenous retrovirus-3 (ERV-3) is an endogenous retrovirus encoding an open reading frame for an envelope protein expressed in placenta. In this study we also found high levels of expression in fetal heart, with peak expression occurring between 11 and 17 weeks of gestation. Antibodies to a peptide corresponding to a predicted epitope of ERV-3 were studied by ELISA in sera from 32 healthy women, 47 women during pregnancy, 19 post-partum, 34 with Sjogren's syndrome (SS), 28 with systemic lupus erythematosus (SLE) and 48 mothers of babies with congenital heart block (CHB). Elevated levels of antibodies to ERV-3 were found in normal pregnancy and in patients with SS or SLE. Compared with normal sera the highest levels occurred in mothers of CHB babies (P < 0.001). Antibodies from sera from three CHB mothers bound to recombinant transmembrane protein of ERV-3 on immunoblots, and to sections of fetal cardiac tissue and placenta. This study has shown evidence of autoimmunization to ERV-3 during pregnancy, with particularly high levels of antibodies in mothers of CHB babies. The expression of ERV-3 in fetal heart and the presence of antibodies in maternal sera suggest a possible role in the pathogenesis of CHB.

Adult↗
PubMed1994

Iron poisoning in children.

Iron overdose is the most common cause of poisoning death in children. Accidental ingestion is common because iron-containing compounds are readily available, brightly colored, often sugar coated, and frequently considered "harmless vitamins" by parents. The management of iron intoxication is controversial. This article describes the clinical presentation of iron overdose and addresses some of the most recent controversies in management.

Adolescent↗
PubMed1993

Inhibition of mitochondrial and Paracoccus denitrificans NADH-ubiquinone reductase by oxacarbocyanine dyes. A structure-activity study.

In this study, we determined that three structurally related oxacarbocyanine dyes, 3,3'-diethyloxacarbocyanine (DiOC2(3)), 3,3'-dipentyloxacarbocyanine (DiOC5(3)), and 3,3'-dihexyloxacarbocyanine (DiOC6(3)), and one oxadicarbocyanine, 3,3'-diethyloxadicarbocyanine (DiOC2(4)), inhibit bovine heart mitochondrial NADH oxidase activity and one of them, DiOC6(3), inhibits Paracoccus denitrificans NADH oxidase activity. The mitochondrial I50 values were 9 microM (DiOC2(3)), approximately 1 microM (DiOC5(3)) and DiOC6(3)), and approximately 3 microM (DiOC2(4)), whereas the I50 value for P. denitrificans was approximately 2 microM (DiOC6(3)). Neither succinate nor cytochrome oxidase (EC 1.9.3.1) activity was inhibited significantly by any of the compounds in either electron transport chain, localizing the inhibitory site of the oxacarbocyanine dyes to the respiratory chain segment between NADH and ubiquinone. With submitochondrial particles (SMP), NADH-dependent reduction of duroquinone and coenzyme Q1 was inhibited markedly by all four compounds with DiOC6(3) being the most potent inhibitor, and the reduction of menadione was inhibited substantially by DiOC6(3). When purified complex I was used, NADH-dependent reduction of ferricyanide was inhibited by DiOC5(3) and coenzyme Q1 reduction was inhibited by all oxacarbocyanines. With P. denitrificans membrane vesicles, DiOC6(3) substantially inhibited NADH-dependent reduction of coenzyme Q1. All the oxacarbocyanines were more effective inhibitors with membrane preparations than with complex I, suggesting that membrane interactions play a role in inhibition. The mechanism of inhibition of the oxacarbocyanines appears to be similar to that of rotenone since (a) essentially only electron acceptors affected by rotenone were affected by the compounds, (b) inhibition of menadione reduction was diminished drastically with rotenone-saturated SMP, and (c) inhibition of coenzyme Q1 was largely eliminated with rotenone-insensitive complex I, and P. denitrificans membrane vesicles.

Animals↗
PubMed1992

In vivo kindling does not alter afterhyperpolarizations (AHPs) following action potential firing in vitro in basolateral amygdala neurons.

Kindling in vivo results in enhanced glutamatergic synaptic transmission and epileptiform bursting in vitro in neurons of the basolateral amygdala (BLA). We tested the hypothesis that reduction of intrinsic inhibitory mechanisms, such as the slow- and medium-afterhyperpolarizations (s-AHPs, m-AHPs), contributes to the enhanced neuronal excitability observed in kindling-induced epileptogenesis using intracellular recording methodology. In these studies, neurons were recorded from the BLA contralateral to the kindling site. AHPs following depolarizing current-induced (100 ms, 1 nA) action potentials were recorded from BLA neurons of control and kindled animals. We found no difference in the amplitude of the s-AHP and m-AHP, or the duration of the s-AHP between control and kindled neurons. In addition, kindling did not alter the distribution of accommodating/non-accommodating BLA neurons (as assessed from neuronal responses during long (500 ms) depolarizing current injection). It is concluded that an alteration in the neuronal network within the BLA rather than a blockade of an intrinsic inhibitory mechanism underlies the enhanced excitability recorded in BLA neurons following kindling.

Action Potentials↗
PubMed1992

Potential of a recombinant antigen as a prophylactic vaccine for day-old broiler chickens against Eimeria acervulina and Eimeria tenella infections.

A genetically engineered Eimeria tenella antigen (GX3262), produced as a fusion protein with beta-galactosidase and identified with a monoclonal antibody, induced partial but significant protection in young broiler chickens against experimental E. tenella and Eimeria acervulina infections. The antigen appears to share a T-helper cell epitope with the parasite as evidenced by (a) booster inoculation with either the recombinant antigen or with a small number of live oocysts enhanced the protective immunity in GX3262 primed chickens, and (b) ability of the antigen to induce in vitro stimulation of T-cells from chickens immunized with antigen or parasite. These observations suggest the feasibility of a single vaccination of 1 or 2-day-old broilers with GX3262 to induce an acceptable degree of protective immunity. The implications of the observations reported here are far reaching in terms of a practical coccidiosis vaccine for poultry, and show for the first time that 1-day-old broiler chickens can be efficiently vaccinated with a recombinant antigen against one or more species of Eimeria.

Amino Acid Sequence↗
PubMed1991

The effects of bayluscide and malathion on the survival of Schistosoma mansoni miracidia.

Laboratory experiments were conducted to assess the toxic effects of bayluscide and malathion against Schistosoma mansoni miracidia. The results indicate that survival of miracidia varied with times of exposure and concentrations of tested chemicals. Statistical analyses reveal that LC5, LC50 and LC95 for bayluscide were 0.04 ppm, 0.06 ppm and 0.12 ppm after 2 hours of exposure; 0.02 ppm, 0.03 ppm and 0.06 ppm after 4 hours of exposure; and 0.01 ppm, 0.02 ppm and 0.04 ppm after 6 hours of exposure respectively. These data indicate that bayluscide is much more toxic to the first stage larvae of schistosomes than to snail intermediate hosts cited in the literature. Application of lower concentrations of molluscicide in the transmission sites is thus expected to curtail the survival of miracidia; therefore controlling schistosomiasis at relatively low costs. Such applications also reduce the risk of toxicity to non target organisms present in the aquatic environment. Statistical analysis of the results of tests using malathion gave LC5, LC50 and LC95 values of 83.38 ppm, 153.11 ppm and 245.85 ppm after 2 hours of exposure; and 76.86 ppm, 116.48 ppm and 172.04 ppm after 4 hours of exposure respectively. These data indicate that the use of malathion as an insecticide in tropical ecosystems may also affect the survival and viability of schistosome miracidia. Such uses could help reducing the risk of schistosomiasis transmission in these particular locations.

Animals↗
PubMed1991

The effects of ammonium sulphate and urea upon egg hatching and miracidial survival of Schistosoma mansoni.

The effects of various concentrations of ammonium sulphate and urea on egg hatching and miracidial survival of S. mansoni were tested in order to determine if the use of these fertilizers in the ricelands of the Republic of Cameroon could affect the transmission of schistosomiasis. Results indicate that hatching of eggs and survival of miracidia varied with concentrations of tested chemicals and times of exposure. Exposure of S. mansoni eggs to 0.20%-1.00% ammonium sulphate or to 0.50%-4.00% urea reduced their ability to hatch and produce miracidia. A chemical concentration of 1.00% ammonium sulphate or 4.00% urea was found to be sufficient to produce complete inhibition of hatching. High concentrations of both chemicals not only inhibited miracidial emergence but also may be ovocidal. Results obtained from miracidial survival tests indicated that LC5, LC50 and LC95 values for ammonium sulphate were 0.07%, 0.80% and 10.61% after 2 hours of exposure; 0.03%, 0.16% and 0.90% after 4 hours of exposure; and 0.30%, 0.20% and 0.40% after 6 hours of exposure respectively. Similar statistical analyses revealed that the LC5, LC50 and LC95 values for urea were 0.22%, 1.90% and 16.25% after 2 hours of exposure; 0.28%, 0.57% and 1.14% after 4 hours of exposure; and 0.13%, 0.27% and 0.57% after 6 hours of exposure respectively. Although the two fertilizers exerted some adverse effects on S. mansoni eggs and miracidia at relatively high concentrations, neither of them was found to be of practical value. Ammonium sulphate and urea concentrations effective in killing S. mansoni eggs and miracidia were about one to two orders of magnitude greater than the actual field application rates.

Ammonium Sulfate↗
PubMed1991

Effects of perfluorodecalin and perfluorooctylbromide emulsions on peak contractile force and ATP levels in the guinea pig left atrium.

The isolated, electrically-driven, guinea pig left atrium was used to study the ability of two perfluorocarbon emulsions to prevent anaerobic hypofunction in the myocardium. A 20% perfluorodecalin (PFD) emulsion maintained peak tension at 80% of aerated levels for more than 20 minutes. Emulsions of perfluorooctylbromide (PFOB) ranging from 25 to 100% produced a similar result, except that the 25% emulsion could not maintain contractions for the entire time period. Peak tension of atria bathed in K-H solution decreased to less than 50% over the same time period. Both 20% PFD and 100% PFOB maintained myocardial ATP levels at pre-hypoxic levels for at least twenty minutes after aeration was terminated. Unaerated atria, bathed in Krebs-Henseleit solution only, exhibited a significant decline in tissue ATP levels at this time. It appears that perfluorocarbon emulsions may delay oxygen desaturation and thereby protect cardiac tissue from ATP depletion and impaired cardiac function associated with hypoxia. This tissue preparation was found to be very useful for determining the efficacy of potential oxygen carriers.

Adenosine Triphosphate↗