Showing papers in "Texas reports on biology and medicine in 1975"

Electromyographic activity of intrinsic and extrinsic muscles of the human tongue.

Abstract: In healthy human subjects, electromyographic activities (EMG) were obtained from various tongue muscles. Main actions such as protrusion, retraction, and changing of the shape of the tongue can be correlated with the EMG activity of the respective muscles. Amongst all tongue muscles the paired genioglossus (protruder) is of greatest importance since it prevents a relapse of the tongue with occlusion of the airways and the attendant risk of suffocation. To counteract the relapse of the tongue, the tonic activity of the genioglossus is markedly increased in the supine position; this activity is further increased with cervical flexion. In addition, the genioglossi are activated during respiration, particularly during the inspiratory phase. These activity patterns reflect the important role the genioglossus plays in the mechanics of maintaining an open air passage to the lungs.

The role of heavy metals in human health.

Abstract: The article reviews the role of heavy metals in human health, including those which are biochemically essential as well as those which have no known role in the normal functioning of the organism but which are toxic. The metals discussed are: cobalt, copper, manganese, cadmium, lead, and mercury. Several are also of concern from the point of view of environmental contamination. The article describes the biochemical role for those metals that are essential, mechanisms of intoxication, intake routes and quantities, and environmental significance.

Antimetabolites of pantothenic acid, ureido- and carbamoyl-derivatives.

Abstract: Pantothenic acid analogs have been synthesized that contain alkyl and/or arylureido and carbamate functions in the beta-alanyl portion of the amide moiety of the vitamin. The analogs are inhibitory to growth of lactic acid bacteria at concentrations as low as 0.6 mug/ml, and the inhibitions are competitively reversed by supplements of pantothenic acid. The carbamate derivatives are more toxic to growth of Lactobacillus plantarum 8014 and Pediococcus cerevisiae 8042 than the ureido analogs, and chloro-substitutents on the aryl group significantly increase the toxicity of the analogs.

A review of the evidence in retrospect for a rickettsial etiology in Bullis fever.

Abstract: The authors have presented evidence through work done 25-30 years ago for the rickettsial etiology of Bullis fever, a forgotten epidemic which occurred with over a 1,000 cases among World War II troops in training at Camp Bullis, Texas. Rickettsiae were recovered from blood and lymph nodes of patients and from ticks, Amblyomma americanum, collected in the area. All patients gave a history of tick-bites. The human and tick strains of rickettsiae, carried in chick embryo culture and in animal passage, were found to produce the characteristic syndrome of Bullis fever in human volunteers inoculated with either strain, indicating identity and specificity of infection. Wildlife in the area was found to support the stages in the life cycle of A. americanum. Deer were implicated as supporting the most abundant adult tick population, the stage which attacks man. Serologic studies eliminated othe rickettsial diseases, Colorado tick fever, dengue and many other diseases. The name Rickettsia texiana is suggested for the hitherto un-named member of the rickettsia group of organisms.

Ergonomics of heat and cold.

Abstract: The biophysical, physiological and some of the psychological aspects of work under unfavorable man-made ambient conditions are presented in light of the need to prevent excessive strain. Work is treated in two ways: 1) in terms of the muscles O2 demand as a fraction of maximal aerobic capacity; and 2) in terms of metabolic heat source. Since maximal aerobic capacity depends on factors such as physical fitness, age and sex, these factors require consideration in estimating strain due to work. The absolute metabolic heat (M) produced during work is needed in the consideration of the total heat balance. Radiation (r), convection (C), and, under some circumstances, evaporation (Eev) are the main avenues of heat exchange between man and his immediate environment. Eev is primarily a function of the ambient potential for evaporation (Emax). Since the relation of the sum M+R+C to Emax determines heat balance when man in under a heat load, evaluation of the avenues of heat exchange, the sources of heat load, and the stressing effect of all these on the physiological responses are treated in some detail. Psychrometrically defined limits of exposure are also discussed. Subjective sensation and mental performance are discussed in light of their correlation with physiological responses to heat. Cold is treated mainly from the point of view of safety and protective clothing.

Anti-inflammatory activity of thiabendazole and its relation to parasitic disease.

Abstract: In 6 differnet animal assays in the laboratory, thiabendazole had clear anti-inflammatory effect, though it was less potent than aspirin in all assays These findings add support to clinical suggestions that the drug may have anti-inflammatory properties in man Such properties may contribute to the clinical response observed following the use of thiabendazole in cases of trichinosis, cutaneous larva migrans, visceral larva migrans, dracunculosis and scabies In parasitic infections in which corticosteroids are commonly used in clinical management, notably trichinosis, the fact that thiabendazole does not appear to have immunosuppressive activity may confer an added clinical advantage

Drug-induced handwriting changes: an empirical review.

Abstract: Since handwriting is a highly complex, coordinated motor activity, handwrits of pharmacological agents. Its potential has been most evident in research involving therapeutic administrations of anti-psychotic an anti-Parkinsonian drugs, from which consistent and systematic handwriting changes have been observed. This relationship has been found to be particularly significant among the anti-psychotics, since the onset of these graphomotor alterations appear to mark the optmal dose of the drug. Consistent and systematic handwriting changes have not been as evident in inivestigations of drugs used in a nontherapeutic atmosphere. Psychiatric assessments of subjects in ths type of research provided data which indicated that psychological stability may be a factor influencing the susceptibility of one's handwriting to drug induced changes.

Genetic influence on saline consumption and salt hypertension as exhibited by the response of various rat strains and sub-strains.

Abstract: Female rats of 2 Sprague-Dawley sub-strains and of the Wistar and Fischer 344 strains were sensitized to the hypertensogenic effect of excess salt by removal of 1 kidney and by being given 1% NaCl solution as their sole drinking fluid. One of the Sprague-Dawley sub-strains (SPD) and the Wistar (CFEP) rats developed progressive saline polydipsia of equivalent degree, blood pressure rose, and about half of the members became hypertensive during treatment. Rats of the other Sprague-Dawley strain (CFNP) also showed a progressive saline intake; but although they drank substantially less saline, the incidence of hypertension among them was increased by 50%. Animals of the Fischer 344 strain displayed neither saline polydipsia--the intake remaining relatively constant at a very low level throughout the experiment--nor hypertension. Salt hypertension appears to be affected by genetic factors in at least 2 ways, one of which regulates the quantity of salt ingested (salt appetite), while the other controls the susceptibility to salt excess or perhaps to hypertension per se. Fischer 344 rats have the ability to restrict the volume consumption of saline; their resistance to enforced high salt intake has yet to be established.

Growth of permanent lymphoid cell cultures from human source: tenth anniversary.

Abstract: The authors developed 52 permanent lymphoid cell cultures from various human sources, mainly from neoplastic lymphoproliferative disease. These cultures are reviewed against the background of similar cultures obtained in several other laboratories. The peculiar features of these cultures are: 1) the phenomenon of lymphoblastoid transformation; 2) the production of both globulins and mediators of delayed hypersensitivity; 3) the presence of herpes type virus as related to etiology or autoimmunity; and 4) cytotoxicity and other assays for the demonstration of tumor-specific antigens.

Age-dependent changes in the morphology of brown adipose tissue in mice.

Abstract: The multocular fat cells of brown adipose tissue of the mouse show an age-dependent change to the unilocular fat cell type. This change starts immediately after birth and continues throughout life. This morphological change can be correlated with the animal's age-dependent decrease in tolerance to a cold environment.

Excretion of HCO3- by the urinary bladder of Bufo marinus in metabolic alkalosis.

Abstract: We studied the role of the urinary bladder of Bufo marinus in the excretion of bicarbonate into the urine. The toads were in metabolic alkalosis, produced by administering 120 mM NaHCO3 by stomach tube or by soaking the toads in 120 mM NaHCO3 solution for 48 to 72 hr. In vitro 10 cannulated whole bladders from toads in alkalosis transported bicarbonate from the serosal to mucosal medium. The average gradient created by this transport was 5.7 meq/1. In 15 whole bladders from toads in metabolic acidosis studied under identical conditions, there was no transport of bicarbonate into mucosal medium.

Serum parathyroid hormone: a double antibody radioimmunoassay.

Abstract: A radioimmunoassay for parathyroid hormone (PTH) using a double antibody system is described. Because of the immunological heterogeneity of the hormone in human serum, the standard used has been serum from a patient with parathyroid carcinoma. With the use of the synthetic 34 amino acid N-terminal fragment of PTH, the anti-PTH antiserum was determined to react primarily with the N-terminal end of the molecule. PTH was detectable in the sera of 25 percent of normal subjects and elevated in 18 of 19 patients with parathyroid adenoma and carcinoma. Serum PTH levels were elevated in 3 of 5 patients with parathyroid hyperplasia.

Uptake of colloidal thorium dioxide by the mouse connective tissue mast cell.

Abstract: The ability of the mouse mast cell to phagocytize colloidal thorium dioxide, Thorotrast, was investigated employing the mouse connective tissue air pouch. The connective tissue mast cell of mouse was found to have limited capability to ingest the particulate Thorotrast in comparison to the rat peritoneal mast cell which ingested this material readily. Fibroblasts and macrophages in the connective tissue removed injected Thorotrast very rapidly in contrast to mast cells that demonstrated limited phagocytic capabilities. The tissue mast cell of the mouse, therefore, should not be considered a part of the reticuloendothelial system.

Air pollution and health.

Abstract: The effects of air pollution on human health are reviewed. Data from toxicology, epidemiology, clinical and laboratory exposures are presented as a basis for an emerging etiology. Sulfur dioxide, suspended particulates, nitrogen dioxide, photochemical oxidants, and carbon monoxide are examined as stress agents to the cardio-pulmonary system.

Community control of Strongyloides stercoralis by thiabendazole.

Abstract: Mass treatment of a community in Costa Rica with thiabendazole in 1965 reduced the prevalence of S. sterocoralis from 19.2% to 0.3%, and the rates remained low 2 years thereafter. Re-examination of the treated population 7 years after initial treatment showed S. stercoralis prevalence still at a 0.5% level.

Morphological changes induced during fixation of Mycoplasma mycoides for electron microscopy.

Abstract: Only spherical mycoplasmas 0.6-0.9 mum diam were observed by darkfield microscopy in single cell suspensions prepared from exponential broth cultures of Mycoplasma mycoides var mycoides and Mycoplasma mycoides var capri. Similar cells were seen in pseudoreplicas by electron microscopy and they are considered characteristic of the morphology of M. mycoides. When the mycoplasmas were fixed by the addition of 10% formalin to the suspensions or washed, centrifuged cells were fixed by glutaraldehyde, filamentous and ring forms were observed in electron micrographs. These are not considered typical of the morphology of M. mycoides but are artifacts produced during the preparation of the mycoplasmas for electron microscopy.

A rapid method for preparing tissue culture clones for light and electron microscopy.

Abstract: Fixation and epoxy-embedment of tissue culture clones in situ were carried out in Falcon tissue culture plates. The clone of cells, retained at one end of the casting, was stained with azure II-methylene blue and then studied with the oil immersion objective. The dimensions of the epoxy casting were ideal for mouting as a block in conventional ultramicrotone chucks. The use of one epoxy casting permits a single preparation of tissue culture clones for direct light microscopic observations and subsequently for ultramicrotomy.

Aflatoxin effects with liquid crystalline cholesteryl esters of duckling sera.

Abstract: An objective of this study was to determine indicator parameters of blood sera that are symptomatic for degenerative hepatic cholesterogenesis and lipid transformations induced with carcinogenic mycotoxins. A technique was developed for electrophoretic separation of liquid crystalline cholesteryl esters within beta lipoprotein fractions of duckling sera. These birefringent moieties decreased to 110 mug/mg low-density lipoprotein during 10-day bioassay periods for normal, nontoxin fed ducklings, but remained unchanged--179-189 mug/mg-for toxin-fed principals ingesting 0.988 mug aflatoxin/g feed throughout the bioassays. Their composition was principally cholesteryl esters with liquid crystalline characteristics determined by the oleate and linoleate content. Increased cholesterol levels--11.4% to 17.1% within sera of the nontoxin group--resulted in more frequent spherulitic mesoforms. The 0.9% to 1.8% taurochenodesoxycholate content within all sera samples induced stable cubic liquid crystalline forms. With polarized microscopy, cholesteric anisotrophs of sera were unique in composition and iridescent visage for each aflatoxin level regime. This specific dicroism was correlated with the corresponding hepatic histology.

Preliminary studies on the metabolism of 3,2'-dimethyl-4-aminobiphenyl in the rat.

Abstract: Distribution of 3,2-dimethyl-4-aminobiphenyl (DMAB) and its metabolites in vivo and the metabolism of DMAB by liver in vitro have been studied in the Wistar rat. DMAB-HCI purified by recrystallization and dissolved in ethanol was injected subcutaneously and extractions made from liver, feces, and urine. Similar technical procedures were used to study in vitro metabolism in rat liver homogenates. Two components were isolated from urine and liver having Rf values (thin-layer chromatography) of 0.13 and 0.59, respectively. Three additional metabolites were found in the hydrolyzed fecal fraction. Rechromatography of the major fecal component yielded 6 fluorescent compounds. Gas-liquid chromatography of the most highly fluorescent of these indicated at least 3 additional metabolites. The evidence presented indicates that the liver transforms DMAB to several metabolites which are rapidly transferred in conjugated form to the intestine via the bile. The urine does not appear to be the major excretory route. We have examined the purity of commercially available DMAB free base and DMAB-HCL and found an impurity that comprises approximately 10-24% of the total samle upon GLC analysis, depending upon the supplier. This contaminant was completely removed by recrystallization of the hydrochloride and the chemical identity of purified compound as DMAB confirmed. Recommendations are presented for the use of this purified compound in a biological system.

Contemporary work-related environmental diseases.

Abstract: This paper is a general review of occupational diseases with particular emphasis on contemporary work-related diseases. Reasons for the difficulties in diagnosis and treatment of industrial disease are given. The basic principles of occupational health are reviewed. The particular occupational diseases discussed in detail are the clinical pneumoconioses, and the contemporary diseases: angiosarcoma from exposure to vinyl chloride and respiratory carcinoma from bichloromethyl ether exposure. Numerous other environmental hazards are mentioned. The role of the Occupational Safety and thealth Administration (OSHA) is discussed, as is the role of the physician from the point of view of taking an appropriate medical history from an occupational vantage and medical diagnosis of occupational disease. Attitudinal aspects are emphasized.