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Biomedical subjects

H C Thompson

Publications and source records attributed to H C Thompson.

At least 37 records · Page 2Linked to original sources
PubMed1987

Can pediatrics meet the challenge of social ill health?

The American Academy of Pediatrics mission statement equates physical, mental, and social health--indeed a major challenge for the profession. This article outlines the magnitude and evolution of physical, mental, and social problems presented to pediatricians during this century. Included are manifestations, and some causes, of social ill health; the response of research and education to the problems; and future steps needed if the challenge is to be met. The unanswered and disturbing question presents itself: Can, or should, pediatrics seriously attempt to meet the challenge of social ill health?

Humans↗
PubMed1985

Analysis of D-penicillamine by gas chromatography utilizing nitrogen--phosphorus detection.

A method is presented for the analysis of the "orphan" drug D-penicillamine (D-Pa), which is used for the treatment of the inherited rare copper metabolism dysfunction known as Wilson's disease, by assaying a derivative of the compound by gas chromatography employing a rubidium sensitized nitrogen--phosphorus detector. Analytical procedures are described for the analyses of residues of D-Pa X HCl salt in animal feed and for the analyses of the salt or free base from aqueous solutions by utilizing a single-step double derivatization with diazomethane--acetone. Stability data for D-Pa X HCl in animal feed and for the free base in water are presented. An ancillary fluorescence derivatization procedure for the analysis of D-Pa in water is also reported.

Animal Feed↗
PubMed1985

Mass spectral characterization of doxylamine and its rhesus monkey urinary metabolites.

This study describes the use of mass spectrometry (MS), high-performance liquid chromatography (HPLC) and chemical derivatization techniques for the identification of doxylamine and five rhesus monkey urinary metabolites. The analyses were performed using chemical ionization mass spectrometry with either methane or ammonia as the reagent gas. The confirmation of the structures of two of these urinary metabolites was aided by the synthesis of doxylamine N-oxide and desmethyldoxylamine and by the use of methylation and acetylation derivatization techniques. Doxylamine N-oxide, desmethyldoxylamine, didesmethyldoxylamine, and two metabolites which resulted from the cleavage of the aliphatic tertiary nitrogen side chain to the subsequent 2-[1-phenyl-1-(2-pyridinyl)ethoxy]acetic acid or 2-[1-phenyl-1-(2-pyridinyl)ethoxy]methanol compounds were isolated and identified from rhesus monkey urine. Additional data concerning the mass spectral analysis of derivatization or reaction products from the three chloroformate reactions with doxylamine, and the synthesis and separation techniques which afforded mass spectral identification of the urinary metabolites are also presented.

Animals↗
PubMed1984

Trace analysis of the antihistamines methapyrilene hydrochloride, pyrilamine maleate and triprolidine hydrochloride monohydrate in animal feed, human urine and wastewater by high-performance liquid chromatography and gas chromatography with nitrogen-phosphorus detection.

Toxicological evaluation of the antihistamines methapyrilene hydrochloride, pyrilamine maleate, and triprolidine hydrochloride monohydrate using methapyrilene hydrochloride as the positive indicator was investigated as part of a structure-activity relationship study in rats and mice. Prerequisites for the toxicological tests were the development of analytical procedures to certify the dose, homogeneity and stability of the drugs in animal feed and to monitor human urine for possible exposure and to ensure removal of the test agents from wastewater prior to its discharge into the environment. A high-performance liquid chromatographic (HPLC) system was developed using a fluorescence detector for the determination of methapyrilene hydrochloride and pyrilamine maleate in feed at levels as low as 100 ng/g and in human urine as low as 1 ng/g. An HPLC-UV procedure was developed for the determination of triprolidine hydrochloride monohydrate in feed at levels as low as 10 micrograms/g. Data concerning p-values, extraction efficiencies from feed and stability experiments in feed are presented for these antihistamines. A gas chromatographic procedure using a nitrogen-phosphorus detector was also developed for determining the three antihistamines in admixture in wastewater at levels as low as 10 ng/g.

Animal Feed↗
PubMed1984

Determination of N-nitrosamines and N-nitrosamine precursors in rubber nipples from baby pacifiers by gas chromatography-thermal energy analysis.

N-Nitrosamines and precursors are present in rubber products in which the accelerators and stabilizers used in the vulcanization process were derived from dialkylamines. Research was performed to develop data concerning the presence of N-nitrosamines and precursors so that the health significance of the exposure problem related to infant ingestion of these chemicals could be properly assessed. Volatile N-nitrosamines were determined in cut-up pacifier nipples by extraction with dichloromethane followed by concentration in a Kuderna-Danish evaporator, high-temperature mineral oil purge and trap, and analysis by gas chromatography--thermal energy analysis (GC-TEA). N-nitrosodibutylamine (NDBA) was the principal N-nitrosamine found, with concentrations up to 427 ppb. N-Nitrosamines and precursors in cut-up and intact nipples were determined by GC-TEA after a single extraction with artificial saliva. NDBA was the principal nitrosamine found, at levels up to 1040 ppb, while dibutylamine (DBA) was the principal precursor found, at levels up to 3890 ppb. The persistence of these compounds in intact nipples was determined by multiple artificial saliva extractions. Amounts of NDBA and DBA found after 15 artificial saliva extractions of intact pacifier nipples totalled 824 ppb and 15.6 ppm, respectively. N-Nitrosamine levels generally showed a gradual decrease in concentration with each extraction, whereas no consistent trend could be determined for concentrations of precursors.

Bottle Feeding↗
PubMed1982

A "marker" technique to monitor treated industrial wastewater effluents.

In toxicological research with hazardous substances (e.g. carcinogens), wastewater effluent from the test facility must be free of such substances before discharge into the environment. An industrial wastewater processing employing adsorbers of carbon and XAD-2 resin is described; however, chemical assays of each batch of treated effluent must certify the absence of all test agents. Elution profiles and adsorption isotherm tests with the test agents vs. the two adsorbents provided the basis for a "marker" technique which should eliminate the necessity to assay for all test agents in each batch of processed effluent. A radionale is presented for periodic introduction of a "marker" (gentian violet) into the primary adsorbers. If detected in the effluent, the "marker", which elutes from the adsorbers before most of the test agents would signal impending depletion of the adsorbent which could then be replaced. Recommendations to modify the industrial wastewater treatment plant and to implement the "marker" technique are presented as cost-effective alternatives to extensive and laborious chemical assays.

Carcinogens↗
PubMed1982

Trace analysis of doxylamine succinate in animal feed, human, urine, and wastewater by GC using a rubidium-sensitized nitrogen detector.

Doxylamine succinate, a drug used as a sleep-inducing agent, an antihistamine, and in a therapeutic formulation taken by pregnant women as an antinauseant, was scheduled for toxicological evaluation as part of a structure activity relationship study, with rats and mice, because a deficiency of such data exists with regard to many antihistamines. Analytical chemical procedures that ensure proper concentration, homogeneity, and stability of the drug in dosed feed, as well as the safety of personnel and the environment, were prerequisites for the toxicological tests. GC methods using a rubidium-sensitized nitrogen detector were developed for analysis of doxylamine succinate in animal feed, human urine, and wastewater at levels as low as 1 ppm, 100 ppb, and 100 ppb, respectively. Sample extracts were cleaned up by liquid-liquid partitioning, followed by additional cleanup on a column of silica gel. Data are presented concerning the stability of the drug in animal feed, extraction efficiencies, and the use of the silica gel cleanup column to separate the caffeine interference from doxylamine in extracts of human urine. Partition values and ancillary data concerning analysis of the drug in feed, by HPLC at levels as low as 10 ppm, are also reported.

Animal Feed↗
PubMed1981

Subjective psychological symptoms in outpatient asthmatic adolescents.

Outpatient adolescent asthmatics were studied using the Asthma Symptom Checklist (ASC) of Kinsman et al. The study showed that outpatient asthmatic adolescents are similar in many respects to older institutionalized asthmatics, except that in the former, psychological symptoms are more diffuse and recognition of respiratory symptoms is less severe. Further studies are needed to determine which psychological symptoms are most important in predicting prognosis in affected asthmatics or the development of "psychosomatic" asthma.

Adolescent↗
PubMed1981

Trace analysis of sulfamethazine in animal feed, human urine, and wastewater by electron capture gas chromatography.

Sulfamethazine, a widely used antibacterial drug additive in feeds for swine, chickens, and cattle, was scheduled for toxicological evaluation because of potential human health hazards associated with its residues in edible animal tissues. Analytical chemical procedures that would ensure proper concentration, homogeneity, and stability of the drug in dosed feed and its safe usage during the animal studies were prerequisites for such toxicological tests. Electron capture gas chromatographic (EC/GC) methods were therefore devised for the analysis of sulfamethazine residues in animal feed, human urine, and wastewater at levels as low as 100, 10, and 10 ppb, respectively. Sample extracts were cleaned up by using liquid/liquid partitioning, and the extracts were subjected to two derivatizations followed by cleanup on a silica gel column. The derivatizations of sulfamethazine consisted of methylation followed by trifluoroacetylation of the primary amine function. Ancillary data concerning stability of the compound in animal feed, water, and as a dry residue on glass, extraction efficiencies, partition values with various solvents, and the analysis of residues in feed by high pressure liquid chromatography (HPLC) at levels as low as 1.0 ppm are presented.

Animal Feed↗
PubMed1978

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Child↗
PubMed1977

Management criteria, recording of performance, and peer review of tonsillopharyngitis.

As part of a national study to formulate criteria for chart audit of quality assurance of child health care, criteria were developed for diagnosis and management of tonsillopharyngitis. These criteria were validated by pediatricians and family physicians in academic medicine and in practice. They were judged relevant to the medical care process and patient outcome by both. The selected criteria were also recommended by the majority of two large physician groups for use in peer review. In the first three phases of the study most of these criteria were said to be performed and recorded by a majority of physicians. However, in the fourth (community) phase, when charts of 166 primary-care physicians were actually audited, documentation was so poor that peer review by chart audit would be impractical at present.

Child↗
PubMed1977

Harvester ant sensitivity: in vitro and in vivo studies using whole body extracts and venom.

Harvester ant stings by Pogonomyrmex maricopa (Pm) or Pogonomyrmex rugosus (Pr) resulted in serious reactions in 8 patients, 4 with generalized reactions and 1 with large local reactions. Exposure to one species in the genus Pogonomyrmex (P) appeared to cross-sensitize ant-sensitive patients to other species in the same genus as evidenced by skin testing and leukocyte histamine release, but these patients were less sensitive to extracts from other stinging Hymenoptera, including bee, wasp, yellow jacket, hornet, and Formica ant. Pr ant venom was obtained by electrical stimulation of live ants for leukocyte histamine release studies. The venom preparation was considerably more effective in inducing histamine release than a body extract derived from gasters, the posterior abdominal segments. Rabbits immunized with an extract from one species produced precipitating antibodies against the injected extract withich cross-reacted with extracts from other species of harvester ant, but not with other stinging Hymenoptera. Humans and rabbits appear to react to certain genus-specific antigens present in Pogonomyrmex whole body extracts. Proper identification of the offending ant is crucial for proper testing and treatment of ant-sensitive patients.

Animals↗
PubMed1976

Quality assurance of ambulatory child health care opinions of practicing physicians about proposed criteria.

This paper reports the opinions of a representative sample of 1,329 physicians providing primary care regarding criteria developed by the Joint Committee on Quality Assurance for evaluation of ambulatory child health care. Areas of care were health supervision (in four age ranges), tonsillopharyngitis, bronchial asthma, and urinary infection. The criteria had been previously appraised by 452 "experts"--academicians and practitioners. Physicians rated criteria for relevance to health outcome, and desirability for use in peer review. They also stated whether they usually performed and recorded each item and gave reasons for not recording. Agreement between the pediatricians and other physicians of the sample and the "experts" was close regarding relevance to health outcome, but many fewer criteria were recommended for peer review by the sample. A significant number of respondents said they performed but did not record many of the criteria. Documentation of only abnormal findings was the main reason given for not recording. Criteria dealing with developmental or behavioral assessment or with counseling were rated lower in all categories than more easily measured items.

Adolescent↗
PubMed1976

Office records in the evaluation of quality of care.

Trained reviewers audited 10,500 charts in the offices of 166 pediatricians and family physicians. Criteria for child health supervision and three diseases had been previously validated for relevance to health outcome and suitability for peer review. Overall documentation of criteria was approximately 50 per cent. Measurements and laboratory data were recorded frequently; counseling items infrequently. Pediatricians documented health supervision items more often than family physicians. Members of large groups recorded more than those in solo practice or small groups. The presence of equipment considered important for health care did not correlate with percentage of recording. The method of review was judged accurate and acceptable by physicians, but only 50 per cent said the results accurately portrayed their performance. Lack of accurate recording may make it impossible to achieve valid peer review of ambulatory child care.

Adolescent↗