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Biomedical subjects

J P McDonnell

Publications and source records attributed to J P McDonnell.

15 recordsLinked to original sources
PubMed2001

The relationship between dental overbite and eustachian tube dysfunction.

OBJECTIVE: The purpose of this study was to investigate the association between deep dental overbite and eustachian tube dysfunction (ETD). DESIGN: Case-control study. SETTING: Tertiary care pediatric otolaryngology outpatient clinic at the Children's Hospital, Boston, Massachusetts. PATIENTS: 105 patients between the ages of 2 and 6 years. STUDY MEASUREMENTS: Dental overbite, overjet, and occlusal relationships were measured by an observer who was unaware of ETD status. ETD was defined as having ventilation tubes in place or having the recommendation for ventilation tube placement by an attending pediatric otolaryngologist. In addition, demographic information and medical and social histories were prospectively recorded. RESULTS: In a multivariate logistic regression model, children with deep bites were 2.8 times more likely to have ETD than those without deep bites (P = .03). Other independent risk factors for ETD identified in this model were family history of otitis media (OM) and age less than 3 years. CONCLUSIONS: Children with deep dental overbites are at a significantly increased risk for developing ETD.

Child↗
PubMed1982

Graphite furnace atomic absorption spectrophotometric determination of 4-hydroxy-3-nitrobenzenearsonic acid, other organic arsenicals, and inorganic arsenic in finished animal feed.

4-Hydroxy-3-nitrobenzenearsonic acid (roxarsone) is administered in animal feed as a growth stimulant over a concentration range of 25-50 ppm. The drug is extracted from 5 g feed with 200 mL aqueous 1.0% ammonium carbonate solution and 5 min of mechanical shaking. Undissolved feed particles are allowed to settle and 1.0 mL aliquot of extract is diluted with 9.0 mL 15% methanol solution. This solution is subjected to sample atomization by a graphite furnace and arsenic detection by atomic absorption spectrophotometry (AAS). Roxarsone recovery from nonmedicated commercial feed fortified at 25 ppm was 103.6% with a relative standard deviation (RSD) of 4.0%. Recovery for 50 ppm fortification was 104.5% (RSD 4.3%). Roxarsone assay results by furnace AAS were compared with results by the current AOAC spectrophotometric method and the AOAC total arsenic method. Results by the 3 methods compare well. The procedure was also used to determine other organic arsenicals and inorganic arsenic in laboratory-fortified feed samples; these recoveries were essentially theoretical.

Animal Feed↗
PubMed1981

High pressure liquid chromatographic determination of nifursol in finished feeds.

Nifursol is extracted from feed with acetonitrile, and then washed with carbon disulfide to remove feed interferences. An aliquot is concentrated, diluted with 5% NaCl solution, filtered, and then subjected to high pressure liquid chromatography on a strong anion exchange column, using 365 nm photometric detection. The average recovery of nifursol from fortified feed samples was 100.6% with an average coefficient of variation of 3.5%. The nifursol determination is not subject to interference from the other commonly used nitrofurans.

Animal Feed↗
PubMed1977

Advancement genioplasty: a retrospective cephalometric analysis of osseous and soft tissue changes.

Serial cephalometric evaluations were made of 15 patients a year after advancement genioplasty to assess skeletal changes, to relate these changes to net soft tissue profile change, and to develop predictive criteria for treatment planning. Coefficients of variance of regression equations, which incorporated selected independent variables, indicated that the variables, interval of time until follow-up records, and the extent of postsurgical horizontal resorption contributed only slightly to the observed variance in prominence of the soft tissue chin. For purposes of prediction, a ratio of 4:3 is recommended for the surgical horizontal advancement of the symphysis versus the net horizontal change in soft tissue chin point.

Bone Resorption↗
PubMed1977

Atomic absorption spectrophotometric determination of dibutyltin dilaurate in finished feeds: collaborative study.

Dibutyltin dilaurate is administered in the feed as an active drug for the removal of large roundworms, cecal worms, and several species of tapeworms from chickens and turkeys. The drug is extracted from finished feed with warm CHCl3, the CHCl3 extract is filtered, and a 25 ml aliquot is concentrated in the presence of methanol until all traces of CHCl3 are removed. The methanol solution is diluted and filtered to remove feed interferences, and then aspirated into an atomic absorption spectrophotometer with a triple-slot burner head, using an air/acetylene flame. The instrument response to tin at 286.3 nm is recorded. Recoveries of 100.5-101.9% tin were obtained for laboratory-prepared feeds. This method was collaboratively studied. The average recovery for dibutyltin dilaurate from 3 feed samples for 8 collaborators was 98.3% with an average coefficient of variation of 5.83%. The method has been adopted as official first action.

Animal Feed↗
PubMed1975

Translation of poly(riboadenylic acid)-enriched messenger RNAs from the yeast, Saccharomyces cerevisiae, in heterologous cell-free systems.

Poly(riboadenylic acid) [poly(A)] enriched messenger RNAs from yeast have been used to direct the synthesis of yeast polypeptides in mouse Krebs II ascites and wheat embryo extracts. Both cell-free systems, synthesize polypeptides over a molecular weight range of 10,000-100,000. Autoradiograms of sodium dodecyl sulfate-polyacrylamide slab gels used to fractionate [35S]methionine-labeled in vitro products reveal that about 25 major bands (each of them possibly representing multiple polypeptides) are produced by each cell-free system. Each of these coelectrophoreses with a major polypeptide labeled in vivo or in a yeast lysate. These results suggest that cell-free translational machinery from eukaryotes is not able to discriminate in an all or none fashion against messenger RNAs which are available to it. While yeast poly(A)-enriched messenger RNA directs the synthesis polypeptides over approximately the same molecular weight range in both cell-free systems, the wheat germ system directs the incorporation of 45 times the amount of [3H]serine into Cl3CCOOH-precipitable polypeptides. This is in contrast to the 2.5-fold more efficient translation of hemoglobin mRNA in the wheat embryo extract. Thus, the extract from mammalian cells is able to translate mRNA from a lower plant with a much lower efficiency than it translates hemoglobin mRNA, and at a lower efficiency than is observed using a cell-free system from wheat embryos. This indicates that the wheat embryo system is the one of choice for translation of yeast messenger RNA.

Adenine Nucleotides↗
PubMed1975

High-speed liquid chromatographic analysis of sulfasalazine (salicylazosulfapyridine).

A high-speed liquid chromatographic method for analysis of sulfasalazine (salicylazosulfapyridine) in bulk powder and tablet dosage form is presented. Analysis is accomplished with a reverse-phase partition column and 10% 2-propanol in pH 7.7 phosphate buffer as the mobile phase. The method of analysis utilizes a simple, one-step, solubilization procedure with dimethylformamide, addition of an internal standard, and chromatography. The method is specific for sulfasalazine in the presence of starting materials, degradation products, or by-products from its manufacture.

Chromatography, High Pressure Liquid↗
PubMed1975

Gas-liquid chromatographic determination of nifursol in frozen turkey tissues to ten parts per billion.

Nifursol (3,5-dinitrosalicylic acid (5-nitrofurfurylidene) hydrazide) is extracted into ethyl acetate from 10 g tissue in the presence of sodium sulfate. Tissue interferences are removed from the tissue extract by washing with petroleum ether after the extract has been transferred into an aqueous solution by evaporation of ethyl acetate. The drug is hydrolyzed under acid conditions to form 5-nitro-2-furaldehyde (5NF). After partition of 5NF from the aqueous phase into benzene the extract is further cleaned up on a Florisil column. The 5NF is eluted from the Florisil column with benzeneethyl acetate. Electron capture gas-liquid chromatography of a 10 mul injection of the concentrated column eluate is the determinative step. Quantitation is accomplished by comparison of the peak height of the sample to the peak height of the standard which is carried through the method simultaneously. Studies of method performance on turkey muscle, liver, kidney, and skin tissues fortified to contain 10 ppb nifursol show a recovery range of 87.4-95.0% and a coefficent of variation range of 5.7-11.2%.

Animals↗
PubMed1975

Atomic absorption spectrophotometric determination of 4-hydroxy-3-nitrobenzenearsonic acid (roxarsone) in premixes.

Roxarsone (4-hydroxy-3-nitrobenzenearsonic acid) is extracted from the premix with aqueous 1% ammonium carbonate. The extract is filtered, diluted, and analyzed by atomic absorption spectrophotometry, using an air-acetylene flame and an arsenic electrodeless discharge lamp. The instrument response of the sample is compared to that of a standard solution of arsenic trioxide. Recoveries range from 99.7. to 100.4% and coefficients of variation range from 0.35 to 0.63%.

Animal Feed↗
PubMed1970

Deoxyribonucleic acid polymerase associated with Rous sarcoma virus and avian myeloblastosis virus: properties of the enzyme and its product.

Deoxyribonucleic acid (DNA) polymerase activity can be elicited in purified preparations of avian myeloblastosis virus and Rous sarcoma virus (Schmidt-Ruppin strain) by treatment with nonionic detergent. The enzyme(s) and its synthetic products appear to be virion-associated. Enzymatic activity can be inhibited by pretreatment with either ribonuclease (8- to 10-fold inhibition) or actinomycin D (twofold inhibition). By contrast, rifampin has little, if any effect. The enzyme(s) synthesizes two primary products, a ribonucleic acid (RNA):DNA hybrid and DNA which is free of RNA. The results of both zonal and equilibrium centrifugation indicate that nascent chains of DNA are associated with the 70S viral RNA. It is concluded that at least two enzymatic activities are under study: transcription of DNA from viral RNA, and subsequent, additional synthesis of DNA, utilizing product of the initial reaction as template.

Avian Leukosis Virus↗