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Biomedical subjects

E M Smith

Publications and source records attributed to E M Smith.

At least 235 records · Page 13Linked to original sources
PubMed1981

Human lymphocyte production of corticotropin and endorphin-like substances: association with leukocyte interferon.

Human leukocyte interferon (hIFN-alpha) preparations contain immunologically and biologically recognizable endorphin and corticotropin-like (ACTH-like) activities. The ACTH bioactivity was demonstrable only after pepsin or acid treatment. Highly purified hIFN-alpha was composed of two molecular species of interferon (18,500 and 23,000 daltons). Endorphin activity was associated with both of these molecules. Pepsin treatment of the 23,000-dalton but not the 18,500-dalton hIFN-alpha generated ACTH activity. In acid, the 23,000-dalton hIFN-alpha broke down into the 18,500-dalton form and ACTH (4500 daltons). The ACTH derived from hIFN-alpha by pepsin digestion comigrated with a purified ACTH standard in NaDodSO4/polyacrylamide gel electrophoresis. hIFN-alpha-producing lymphocytes showed positive immunofluorescence after staining with highly specific antisera to ACTH alpha-(1-13) and gamma-endorphin. Essentially 100% of the human peripheral lymphocytes were capable of producing both ACTH and gamma-endorphin-related substances, presumably associated with hIFN-alpha. These results strongly suggest a circuit between the immune and neuroendocrine systems which involves neuroendocrine hormone-like substances, some of which are associated with hIFN-alpha

Adrenocorticotropic Hormone↗
PubMed1981

Human B lymphocytes produce leukocyte interferon after interaction with foreign cells.

Enriched human B-cell populations cocultivated with xenogeneic or allogeneic tumor cells produced 1,000 to 10,000 U of leukocyte interferon per ml. In contrast, cocultivation of enriched plastic-adherent or T-cell populations with xenogeneic or allogeneic cells produced only 10 to 30 U of interferon. The population of cells producing the interferon absorbed to nylon wool and not sheep erythrocytes. They showed a strong mitogenic response to the B-cell mitogen Escherichia coli lipopolysaccharide but not the T-cell mitogen staphylococcal enterotoxin A. In addition, treatment of this cell population with goat anti-human immunoglobulin M and complement depleted the cell population synthesizing the interferon. Together, these in vitro findings strongly suggest that the cells producing most of the interferon after interacting with foreign cells belong to the B-cell population. These results also suggest that the cells that produce most of the leukocyte interferon after interacting in vivo with tumors or other cells made foreign to the body by certain viruses most likely belong to the B-lymphocyte population.

Animals↗
PubMed1981

Use of active patient follow-up in cancer registries for designing epidemiologic studies.

The two primary functions of a population-based cancer registry are to collect incidence data and survival data, often obtained by active contact methods. Because of the expense and complexities of epidemiological research in determining carcinogenic risk, existing aggregate data collection systems need to be utilized for generating hypotheses. Direct follow-up contact with a patient by mail provides a mechanism for identifying potential risk factors at low cost. This method is being used to solicit information concerning environmental exposure. In addition, analysis of preliminary data on education and occupation collected by the mechanism indicated that staying patterns of cancer differ between rural and urban areas in the state of Iowa. The difference appears to be explained by education and not by occupation.

Follow-Up Studies↗
PubMed1980

Human leukocyte interferon: structural and biological relatedness to adrenocorticotropic hormone and endorphins.

Anti-alpha-corticotropin [anti-ACTH alpha (1-13)](also alpha-melanotropin) and anti-gamma-endorphin antisera neutralized human leukocyte interferon activity but not fibroblast interferon activity. Human leukocyte interferon was not neutralized by anti-human lutenizing hormone (lutropin) or follicle-stimulating hormone (follitropin) antisra. Conversely, antisera to human leukocyte interferon neutralized ACTH activity. The neturalization of human leukocyte interferon by anti-human leukocyte interferon serum was partially blocked by ACTH. These studies show strong antigenic relatedness among human leukocyte interferon, ACTH, and endorphins, implying that there are underlying structural similarities. Structural relatedness is shown by pepsin cleavage of ACTH activity from human leukocyte interferon. The implication for the natural functions of human leukocyte interferon are discussed.

Adrenocorticotropic Hormone↗
PubMed1980

A coupled-enzyme equilibrium method for measuring urea in serum: optimization and evaluation of the AACC study group on urea candidate reference method.

We describe a coupled-enzyme equilibrium method for measuring urea in serum, which is performed on supernates prepared by treating each specimen with Ba(OH)2 and ZnSO4 (Somogyi reagent). Analytical recovery of [14C]urea added to a variety of matrices was essentially complete (mean, 100.6%) for the supernates after precipitation. Nine variables were univariately examined in arriving at the reaction conditions for the method: glutamate dehydrogenase, urease, 2-oxoglutarate, ADP, Tris . HCI, NADH, EDTA, pH, and temperature. The reagent is stable for at least 48 days at--20 degrees C and for 23 days at 4 degrees C. Mean analytical recovery of urea (14 mmol/L) added to seven different specimens (three different matrices) was 100.8%. The analytical linear range of the method extends to 30 mmol of urea per liter. Of 22 potential interferents, only bilirubin at 1 mmol/L (580 mg/L), hemoglobin at 10 g/L, and hydroxyurea at 6 mmol/L showed more than 2% interference. We discuss precision and effects of specimen dilution, and compare results for 100 human serum specimens with those measured for the same specimens with four other urea methods. We examined the effects of measuring a blank, consisting of sample and reagent without urease, with each specimen.

Animals↗
PubMed1979

Rotavirus stability and inactivation.

The stability of the infectivity of Simian rotavirus, SA11, has been analysed and compared to the stability of reovirus type 1. SA11 infectivity was stable to freeze-thawing, sonication, incubation at 25 degrees C overnight or at 37 degrees C for 1 h and to treatment with acid, ether, chloroform and Genetron. In contrast to reovirus, the infectivity of SA11 was more rapidly inactivated by heating at 50 degrees C. SA11 infectivity was inactivated above pH 10.0 and by heating at 50 degrees C in 2 M-MgCl2, but was stabilized by heating in 2 m-MgSO4; reovirus 1 infectivity was enhanced by heating in MgCl2. Both SA11 and reovirus 1 were inactivated by freezing in MgCl2. These results show that rotaviruses and reoviruses can be distinguished by their patterns of inactivation by physical and chemical agents.

Animals↗
PubMed1979

A plaque assay for the simian rotavirus SAII.

A sensitive, quantitative and reproducible plaque assay for the measurement of the simian rotavirus SAII is described. Plaque formation required the presence of the facilitators pancreatin or trypsin and diethylaminoethyl-dextran in the agar overlay. SAII produced plaques in three continuous primate cell lines: MA-104, CV-1 and LLC-MK2. MA-104 cells were the most sensitive.

Animals↗
PubMed1979

Simian rotavirus SA11 replication in cell cultures.

Understanding the basic virology of rotavirus infections has been hampered by the fastidiousness of most isolates and by the lack of a rapid quantitative assay method. The growth characteristics of the simian rotavirus SA11 were studied because it grows to high titers in tissue culture and infectivity can be quantitated by plaque assay. SA11 replication was analyzed in a variety of primary cell cultures or continuous cell lines derived from both homologous and heterologous hosts. Viral replication was observed in each of the cell cultured examined. The individual cell cultures demonstrated marked variability in their susceptibility to rotavirus infection. The highest titers were obtained with MA104, BSC-1, CV-1, and BGM cells. Observable cytopathic effect was found to correlate with the percentage of infected cells in the culture. This study presents growth curves of the simian rotavirus in a variety of cell cultures.

Animals↗
PubMed1979

Single-photon transaxial emission computed tomography of the heart in normal subjects and in patients with infarction.

Resting computerized transaxial tomography was performed after the i.v. injection of thallium-201 in six normal subjects and in five patients who had had myocardial infarctions 3 mo to 4 yr before scintigraphy. Decreased myocardial activity corresponded to the site of previous infarction in all cases and was clearly separated from adjacent myocardium with normal activity. With tomography, the left ventricle was clearly separated from surrounding structures such as the left-ventricular cavity, the lungs, and the liver. This study demonstrates the feasibility for the assessment of myocardial perfusion using single-photon transaxial emmission computed tomography.

Heart↗
PubMed1979

Epidemiology of oral and pharyngeal cancers in the United States: review of recent literature.

Recent literature on morbidity and mortality patterns, known risk factors, and related sociobehavioral characteristics of oral cancer have been examined. Despite variation in populations and methodologies, alcohol and tobacco were seen as the major independent etiologic agents; these effects were associated with age, sex, and religion-ethnicity. Other factors were suggested, but their correlation was less consistent: geographic location, race, socioeconomic status, nutrition, dental conditions, and concurrent diseases. Social and behavioral components may alter risk, stage of disease at diagnosis, treatment or survival from oral cancer. The impact of sociobehavioral elements on the reduction of the incidence of and the mortality from the disease is an important area needing further investigation.

Alcohol Drinking↗
PubMed1979

Biological distribution and excretion of DTPA labeled with Tc-99m and In-111.

For the purpose of radiation dose estimates, organ assays and excretion measurements of the Tc-99m and In-111 complexes with DTPA were conducted in dogs at various time intervals up to 24 hr, and the results compared with available human data. The peak concentration of the Tc-99m complex, at 3 min after injection, was 5% of the administered dose for one kidney, 3.5% for the liver, and 3.5% for the small bowel. No organ system except the urinary tract reached a concentration higher than that in blood for several hours after the injection. The biliary excretion of these agents was extremely low, and their elimination in the feces was negligible. In man, it appears that the residual 4-5% of an administered dose not eliminated in the urine by 24 hr is widely distributed in various tissues. The distribution of the In-111 complex is similar but not identical to that of the Tc-99m complex.

Animals↗
PubMed1978

Comparison between adsorption of poliovirus and rotavirus by aluminum hydroxide and activated sludge flocs.

Adsorption of poliovirus and rotavirus by aluminum hydroxide and activated sludge flocs was studied. Both aluminum hydroxide and activated sludge flocs adsorbed greater amounts of poliovirus than rotavirus. Aluminum hydroxide flocs reduced the titer of poliovirus in tap water by 3 log10, but they only reduced the titer of a simian rotovirus (SA-11) in tap water by 1 log10 or less and did not noticeably reduce the number of human rotavirus particles present in a dilute stool suspension. Activated sludge flocs reduced the titer of added poliovirus by 0.7 to 1.8 log10 and reduced the titer of SA-11 by 0.5 log10 or less. These studies indicate that a basic difference in the adsorptive behavior of enteroviruses and rotaviruses exists and that water and wastewater treatment processes that are highly effective in removal of enteroviruses may not be as effective in removing other viral groups such as rotaviruses.

Adsorption↗
PubMed1978

Role of sediment in the persistence of enteroviruses in the estuarine environment.

The survival of four enteroviruses commonly found in sewage effluents was examined when the viruses were adsorped to marine sediments in estuarine water and compared with virus survival in estuarine water alone. Echovirus 1, coxsackieviruses B3 and A9, and poliovirus 1 survived longer when associated with marine sediment. When the estuarine water was polluted with secondarily treated sewage effluent, virus survived for prolonged periods in sediments, but not in the overlaying estuarine water.

Enterovirus↗