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Biomedical subjects

R M Burton

Publications and source records attributed to R M Burton.

At least 19 recordsLinked to original sources
PubMed1992

Evaluation of high volume particle sampling and sample handling protocols for ambient urban air mutagenicity determinations.

An investigation of high volume particle sampling and sample handling procedures was undertaken to evaluate variations of protocols being used by the U.S. Environmental Protection Agency. These protocols are used in urban ambient air studies which collect ambient and source samples for subsequent mutagenicity analysis of the organic extracts of the aerosol fraction. Specific protocol issues investigated include: (a) duration of sampling period, (b) type of filter media used to collect air particles, (c) necessity for cryogenic field site storage and dry ice shipping of filter samples, and (d) sample handling at the receiving laboratory. Six PM10 Hi-Vol samplers were collocated at an urban site in downtown Durham, North Carolina and operated simultaneously to evaluate 12 h versus 24 h collection periods and filter media choices of glass fiber, Teflon impregnated glass fiber (TIGF), and quartz fiber. Filters from the samplers plus field blanks were collected during each of 25 sampling periods. TIGF filters from two samplers were immediately placed on dry ice in the field and transported directly to cryogenic storage. TIGF, quartz, and glass fiber filters from three samplers were transported at ambient and maintained at room temperature for three to six days prior to cryogenic storage. One TIGF sample, which was collected on a previously tared filter, was subjected to controlled environment equilibration (40 percent relative humidity, 22 degrees C) for 8 to 24 h and weighed prior to cryogenic storage. All filters were subsequently stored at -70 degrees C to -80 degrees C prior to a one-time extraction and Salmonella (Ames) mutagenicity bioassay of the entire sample set.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants↗
PubMed1991

Do patients presenting to accident and emergency departments have low serum anticonvulsant concentrations?

It is often felt that poorly controlled epileptic patients, who are taking anticonvulsant medication, are over represented in A&E departments compared to the general population. This A&E based study set out to determine whether such patients do have inadequate serum anticonvulsant levels, when they present following a seizure, to A&E departments. All epileptic patients, taking medication, who presented to the A&E departments of St. Bartholomew's and Hackney Hospitals, London, over a 4-month period were studied. Serum anticonvulsant concentrations were measured on their arrival in the departments. Forty-six patients were studied. Only 21% of anticonvulsant drug concentrations were within 'therapeutic' ranges. A total of 66% were below 'therapeutic' ranges and 13% were potentially toxic. The implication of these findings is discussed.

Adolescent↗
PubMed1979

Occurrence of a thermostable antigen of ovarian carcinoma in normal tissues and secretions.

Thermostable antigen (TA) occurs in ovarian carcinoma and in certain specialized tissues. High titers of TA were found in nineteen of twenty endocervical extracts but not in myometrium, endometrium, or exocervix. TA was present in all of sixteen cervical mucus samples. Antibodies to perchloric acid extract of bronchus showed cross-reaticity with TA from ovarian carcinoma and cervix. Immunofluorescence with frozen sections revealed TA to be present in the columnar epithelium of ovarian neoplasms, and endocervical glands, in bronchial seromucous glands and in hepatic bile canaliculi. Immunofluorescence and immunodiffusion were used to test for cancer patient antibodies against TA. All sera tested negative. An immunofluorescence inhibition test for circulating TA also tested negative in sera of ovarian and cervical cancer patients.

Adult↗
PubMed1979

Blood pressure in a high school population. II. Clinical profile of the juvenile hypertensive.

One-hundred-fourteen hypertensive high school students were evaluated to determine whether a distinctive clinical profile could be identified; 71 normotensive students served as controls. Selected blood chemistry determinations, urinalysis, and chest roentgenograms were done to help rule out secondary causes of hypertension. Left ventricular function was assessed by echocardiography and systolic time intervals. The hemodynamic response to exercise was also evaluated. A significant number of the subjects 14 to 18 years of age with persistent systolic and/or diastolic pressure 1.65 SD above the mean for age and sex showed the following: obesity; elevated serum triglyceride concentration; basilar hypertrophy by electrocardiogram/vectorcardiogram; electromechanical systole and pre-ejection period shorter, and the ratio of the pre-ejection period over the left ventricular ejection time lower, than mean for age and sex as determined by systolic time intervals; volume indices depressed and cardiac contractile functions elevated as determined by echocardiography; higher blood pressure at start of exercise stress test and higher peak systolic and diastolic pressures during test, and a slower return of heart rate to base line level after the test. The above findings should be useful in following the course of a young individual with essential hypertension and may provide a means of evaluating therapeutic intervention.

Adolescent↗
PubMed1979

Acute menopausal transition associated with clomiphene therapy: Two case reports.

Two patients presenting with anovulation and secondary infertility were treated with clomiphene citrate. Intermittent blood samples were obtained for the first three months of therapy in each case. One patient failed either to ovulate or menstruate in response to clomiphene and the other patient had only two episodes of cyclical bleeding before she too became amenorrhoeic. Hormonal analyses revealed that both women had undergone a rapid and precocious menopausal transition which has persisted throughout the subsequent three years.

Adult↗
PubMed1978

Immunochemical detection of human blood in feces.

Current methods for testing stool samples for hemoglobin utilize peroxidase oxidation of chemical indicators such as guaiac or benzidine. These tests have frequent false-positive and false-negative results, complicating random screening for occult gastrointestinal bleeding. The authors have developed an immunochemical test for human blood in feces using goat antibodies to hemoglobin. When employed in radial immunoassay the test is uncomplicated by cross-reaction with common human foods or other nonhemorrhagic fecal fecal constitutents. The lower limit of sensitivity for hemoglobin in stool samples is 10 mg/dl, compared with a commonly reported threshold of 100 mg/dl for peroxidase tests. The test accurately detects hemoglobin in mixtures of human blood and feces. Immunochemical identification of human blood in stool offers improved detection of lower gastrointestinal bleeding.

Animals↗
PubMed1978

[Tissue antigens in ovarian carcinoma].

Five tissue antigens have been identified which appear in carcinoma arising in the ovary. Antisera to a variety of human tissues were absorbed with a saline extract of normal ovary as well as plasma; five distinct antigens (A1-A4, TA) were detected in ovarian tumor extracts as well as in normal tissues. A1, A2, and A3 were widely distributed in normal tissues while A4 was found principally in buffy coat blood cells and spleen, and TA was mainly associated with normal cervix but was variably detected in liver and lung. Heating the tumor extract to 56 degrees resulted in inactivation of A1, A2, and A3. A4 was inactivated at 80 degrees, whereas TA was stable at 100 degrees. Pronase treatment readily abolished A3 activity, more slowly inactivated A1, A2, and A4, and only very slowly destroyed TA. Partial separation of the antigens was obtained by Sephadex G-200 chromatography. TA from individual benign and malignant tumors as well as normal cervix appears to be the same molecule by criteria of immunodiffusion, immunoelectrophoresis, and gel filtration. The potential use of these antigens as tracers of ovarian carcinoma is indicated.

Antigens↗
PubMed1978

Exploratory monitoring of air pollutants for mutagenicity activity with the Tradescantia stamen hair system.

The Tradescantia genetic system developed by the late Dr. Arnold H. Sparrow for the study of effects of ionizing radiation is applicable to chemical mutagen detection. Early radiobiological data demonstrated that the stamen hairs were sensitive to as little as 0.25 rad of x-rays and that the number of cells showing a phenotypic change in pigmentation from blue to pink plateaus after approximately 21 days of chronic, low-level irradiation. Exposures to the air pollutants SO(2), NO(2), and O(3) and to vapors of mutagens such as 1,2-dibromoethane (DBE) and ethyl methanesulfonate (EMS) demonstrated the usefulness of the system as a detector of chemical mutagens. A significant number of phenotypic changes was observed following exposures to as little as 0.14 ppm of DBE. The maximum sensitivity of the system is obtained with long-term or chronic exposures because the response increases linearly in proportion to the duration of exposure up to 21 days. To monitor industrial sites for atmospheric mutagens a mobile laboratory was designed to support plant culture in the field. Environment-controlled growth chambers were installed in a trailer so that both ambient air fumigations and concurrent clean-air control exposures could be made. Sites monitored by the mobile laboratory were: Elizabeth, N. J.; Charleston, W. Va.; Birmingham, Ala.; Baton Rouge, La.; Houston, Tex.; Upland, Calif.; Magna, Utah; and Grand Canyon, Ariz. The latter site at Grand Canyon served as a clean air control study. Atmospheric contaminants from petroleum and chemical processing plants generated a significant number of phenotypic pigment changes that were 17 to 31% above the control levels; contaminants from steel and copper smelters, automotive combustion products and photochemical compounds were negative. Chemical analyses are underway to identify the atmospheric mutagens at the sites that showed a positive response.

Air Pollutants↗
PubMed1977

Reaction of selenium with immunoglobulin molecules.

Radioactive selenite reacts with purified human and goat immunoglobulins at acidic and neutral pH. The antigenic properties of the immunoglobulins are retained during the selenium labelling as shown by immunoelectrophoresis and autoradiography. Pepsin digests of 75Se-labelled IgG possess 75Se both in the (Fab')2 fraction and in the low molecular weight peptides derived from the Fc domains. Alpha-1-acid glycoprotein, ribonuclease, and lysozyme are also labelled by this procedure. Enhancement of 75Se incorporation by urea, guanidinium chloride, mercaptoethanol, sodium sulfite and carrier selenite is interpreted as an effect of destabilization of IgG disulfide bonds. Up to 1.4 g atoms Se per mol IgG have been incorporated. We assume that selenite is cleaving disulfides by a process akin to sulfitolysis. The lability of the isolated 75Se-labelled IgG to high concentrations of mercaptans and sulfite is consistent with this idea. These 75Se-labelled proteins may be useful in structure studies and radioimmunoassay.

Animals↗
PubMed1977

Tissue antigens in ovarian carcinoma.

Five tissue antigens have been identified which appear in carcinoma arising in the ovary. Antisera to a variety of human tissues were absorbed with a saline extract of normal ovary as well as plasma; five distinct antigens (A1-A4, TA) were detected in ovarian tumor extracts as well as in normal tissues. A1, A2, and A3 were widely distributed in normal tissues while A4 was found principally in buffy coat blood cells and spleen, and Ta was mainly associated with normal cervix but was variably detected in liver and lung. Heating the tumor extract to 56 degrees resulted in inactivation of A1, A2, and A3. A4 was inactivated at 80 degrees, whereas TA was stable at 100 degrees. Pronase treatment readily abolished A3 activity, more slowly inactivated A1, A2, and A4, and only very slowly destroyed TA. Partial separation of the antigens was obtained by Sephadex G-200 chromatography. TA from individual benign and malignant tumors as well as normal cervix appears to be the same molecule by criteria of immunodiffusion, immunoelectrophoresis, and gel filtration. The potential use of these antigens as tracers of ovarian carcinoma is indicated.

Antigens, Neoplasm↗
PubMed1976

A thermostable antigen associated with ovarian cancer.

Ovarian carcinoma contains an antigen (TA) which is stable at 100 degrees. Rabbit antisera to glycoprotein-rich extracts of tumors detect TA in 70 per cent of ovarian malignancies, in some benign ovarian cysts, certain normal lung preparations, normal cervix, and squamous-cell carcinoma of the cervix. Highest levels may be associated with mucin secretion. No detectible antigen was present in normal ovary, plasma, A, B, and O erythrocytes, leukocytes, placenta, brain, heart, liver, corpus uteri, spleen, skeletal muscle, or kidney. Prolonged digestion of boiled tumor extracts with papain, trypsin, chymotrypsin, on Sephadex G-150 corresponding to a globular protein of 27,000 to 36,000 molecular weight. A beta-globulin mobility is seen in immunoelectrophoresis. It appears that TA differs in tissue specificity and molecular size from other known ovarian cancer associated antigens.

Antigens, Neoplasm↗
PubMed1976

Morphological and biochemical characterization of light and heavy myelin isolated from developing rat brain.

Myelin from developing rat brains was separated on a discontinuous sucrose gradient into subfractions of two different densities, i.e. light and heavy myelin. Electron photomicrographs showed that heavy myelin consisted primarily of large compacted multilamellar structures with a distinct intraperiod line characteristic of myelin in situ. Light myelin, on the other hand, was composed of small vesicles having a unilamellar structure. Similar to whole myelin, both membrane subfractions were highly enriched in 2',3'-cyclic nucleotide-3'-phosphohydrolase. The specific activity of the enzyme, however, showed no developmental trend. Both subfractions contained all the four major proteins characteristic of the whole myelin membrane. There were, however, quantitative differences in the relative distribution of these proteins between light and heavy myelin. Basic protein accounted for 55% and proteolipid protein for 46% of the total myelin proteins of light and heavy myelin, respectively. DM-20 (Agrawal, H.C., Burton, R. M., Fishman, M.A., Mitchell, R.F. and Prensky, A.L. (1972) J. Neurochem. 19, 2083-2089) exhibited a developmental "switch" between light and heavy myelin. Light myelin appeared to contain more DM-20 in 15- to 20-day-old rat brain, whereas the concentration of this protein was higher in heavy myelin at subsequent ages studied.

Aging↗
PubMed1976

Accumulation and turnover of the classical Folch-Lees proteolipid proteins in developing and adult rat brain.

The turnover of classical Folch-Lees proteolipid proteins was studied after administration of [2,3-3H]tryptophan to both developing and adult rat brain. The animals were killed from 2h to 250 days after subcutaneous injections of [3H]tryptophan. The measured specific radioactivity in developing brain attained maximum value 24h after the administration of label, whereas the total radioactivity per brain reached a maximum 21 days after injection. The half-life of proteolipid protein from the measured specific radioactivity was 7-20 days, depending on the time-points used for the calculation, whereas calculation from total radioactivity between 28-77 and 91-257 days gave half-lives of 35-40 and 188 days respectively. In contrast, in animals injected at 40 days of age, the half-life from the whole-brain-radioactivity data was 188 days. The problem of the recycling of radioactivity for the synthesis of myelin proteins from either a general or a discrete amino acid pool is discussed.

Age Factors↗
PubMed1976

Estimating the impact of health services in a community.

The advantages of clinical and mechanical combination of observations for prediction are mutually reinforced by an application of Bayesian statistics. The technique is shown to be particularly advantageous in a situation which is characterized by a paucity of observations available to suppliment a prior expert judgment. The approach also presents a basis for evaluating relative expertise and tracing the learning experience of experts. Taking the community as the organizational level of analysis, data on the classification of aged persons in Durham County, North Carolina, and data on the changes in classification of these individuals within the population over time are gathered and studied. These data are combined with clinical judgments of changes as a demonstration of the merits of the technique developed in this paper.

Aged↗