Modification of the process of resorption of alpha-emitting nuclides from the gastrointestinal tract depending upon the properties of administered compounds and the physiological state of rats

In experiments on rats a study was made of resorption from the gastrointestinal tract of simple salts, complex compounds and "biologically incorporated" forms of transuranium nuclides, the influence of age, pregnancy and chemically active substances (for instance, trivalent iron and ethyl alcohol) on this process.     

Modification of the radiosensitivity of E. coli cells by factors affecting the yield of photoreactivated damage

A study was made of the influence of irradiation conditions on the yield of the photoreactivable damages in radiosensitive mutants of E. coli cells (E. coli WP2). Pyrimidine dimers were shown to occur in exrA- and recA- mutants irradiated under anoxic conditions, the survival of these mutants being modified depending on cell genotype. The processes of direct excitation of the molecules were involved in the formation of the damages observed. It can be assumed that the lesser oxygen effect observed in exrA- and partially in recA- mutants of E. coli WP2 cells is associated with a contribution of the photoreactivable damages to a lethal effect of ionizing radiation.     

Effect of radioprotective agents on the epithelium of small intestine mucosa in irradiated animals

In experiments on irradiated (10 Gy) mice a study was made of the morphological changes in the small intestine mucosa and in its functional status estimated by absorption of stain uranine. It was shown that the preventive administration of cystamine and S-(omega)-aminopropyl-beta-aminoethylthiophosphoric acid to the exposed mice increased the proliferation processes in the crypt and the cell movement per villus providing a favourable effect of the radioprotective agents on the absorption function.     

Purification and properties of a coagulant proteinase isolated from bushmaster (Lachesis muta) venom (Serpentes: Viperidae)

The venom of Lachesis muta is a rich source of a thrombin-like enzyme. Its coagulant proteinase was purified by DEAE -Sephadex A -50 followed by agmatine CH -Sepharose and gel filtration on Sephadex G-100. On polyacrylamide gel electrophoresis at pH 8.4 a single band was observed. Its molecular weight by gel filtration was 49,000. The coagulant and esterolytic activities toward human fibrinogen and Tame of the inudasa were 662 NIH units/mg of protein and 4.37 delta OD225/min x 10(-3)/micrograms/ml, respectively. These values represent 23 and 5.7 fold increase over the crude venom. The enzyme mudasa, was evaluated with serum from human patients at Hospital Nacional de Ni?os Dr. Carlos Sáenz Herrera and found to be a valuable reagent for the quantification of fibrinogen on heparinized plasma.     

Seasonal variation of neural tube defects in Newfoundland and elsewhere

In Newfoundland, babies with anencephaly are conceived most often in January, and those with spina bifida in August. These and previous observations suggest that (1) seasonal fluctuations are greatest when the population frequency is neither very high nor very low, and that (2) the peak season for conception of anencephalic babies may occur in any season except August-November in various populations, whereas for spina bifida seasonal peaks are confined almost exclusively to May-August.     

Radioimmunoassay of urinary 3 beta-hydroxy-5-cholenoyl glycine in hepatobiliary disease

A radioimmunoassay for 3 beta-hydroxy-5-cholenoyl glycine in human urine has been developed. The antiserum was elicited with the antigen in which the steroid hapten is linked to a bovine serum albumin through the C-19 position. The [125I]-tyrosine derivative of the hapten was used as radioligand. The standard curves were linear ranging from 10 to 320 ng/mL. The cross-reactivities with other bile acids were not detectable and below 0.3% with cholesterol. Sample preparation includes extraction of 3 beta-hydroxy-5-cholenoyl glycine from urine and solvolysis of the sulfates--main form present in urine. Urinary excretion of 3 beta-hydroxy-5-cholenoyl glycine was 0.373 +/- 0.133 mumol/day in healthy adults. Urinary excretion of 3 beta-hydroxy-5-cholenoyl glycine increased in chronic liver dysfunction, hepatoma and obstructive jaundice in this order.     

Influence of carbohydrate side chains on activity of tissue-type plasminogen activator

When messenger RNA (mRNA) from both untreated and phorbol ester-treated melanoma cells is translated in simple reticulocyte lysates, tissue-type plasminogen activator can be immunoprecipitated by an affinity-purified antibody as a approximately 52,000 mol wt protein, with no detectable biological (plasminogen activating) activity. When the reticulocyte lysate system is supplemented with a preparation of microsomal membranes, biological activity becomes detectable and a 63,000 mol wt protein can be immunoprecipitated with the same antibody. Furthermore, when natural tissue-type plasminogen activator (mol wt approximately equal to 70,000) is incubated with different glycosidases, distinct alterations in the electrophoretic mobility of the molecules are observed, together with alterations in the level of biological activity. While treatment with neuraminidase and beta-galactosidase caused decreases in activity, alpha-mannosidase caused an increase. These results suggest that the carbohydrate part of the molecule can influence its biological behavior.     

Segregation function of the cell and its molecular mechanisms

Current literature on the cell segregation function is reviewed. The modern data on the role of coated pits, coated vesicles and endosomes in receptor-mediated and fluid endocytosis are regarded. Mechanisms of segregation both of inorganic and organic substances in lysosomes are considered. A special attention is paid to the selective accumulation in lysosomes of substances penetrating through plasma membrane. Some modern considerations concerning the role of the ATP-dependent proton pump in maintaining low intralysosomal pH and accumulation of weak bases in lysosomes by means of protonation are given. A great attention is paid to the effect of accumulated foreign substances in lysosomes on lysosomal apparatus functions and some metabolic disorders as consequences of it. The importance of the cell segregation functions and of lysosomotropic compounds for cytopharmacology and cytopathology is emphasized.     

Effect of the segregation of neutral red, acridine orange and ammonium chloride by L cells (subline LSM) on lysosomal hydrolase activity

Kinetics of Neutral red (NR) and Acridine orange (AO) uptake by cultured L cells (subline LSM) has been studied. It was found that the uptake of both NR and AO, with their constant concentrations in the medium was characterized as a two-phase process. During 2 hours, these cells concentrated as much as 90% of the total amount of NR and AO taken up during the whole incubation period. The segregation and accumulation of NR, AO as well as NH4Cl took place in lysosomes. NR and AO concentrations within the cells exceed by 600 and 400 times, respectively, those in the medium. NR, AO and NH4+ accumulation in cells resulted in inhibition of the activity of the following lysosomal hydrolases: cathepsins B and D, acid lipase, N-acetyl-beta,D-glucosaminidase, beta-galactosidase, acid phosphatase and galactosyltransferase, the latter being a marker of Golgi apparatus. The effect of lysosomal enzyme activity inhibition on the cell economy, and a possible role of lysosomotropic agents as regulators of the lysosomal apparatus functional activity are discussed.     

Bronchiectasis revisited

The writer of this retrospective essay witnessed his first open chest operation during the academic year 1928-29 while an intern in general surgery at Lakeside Hospital, Cleveland, Ohio. The operative procedure was probably the first of its kind to be performed at that teaching hospital, and it involved the excision of a mediastinal tumefaction through a median sternotomy. Now, more than fifty-five years and several thousand thoracic operations later, the author recounts the evolution of pulmonary resection, particularly in relation to the therapy of bronchiectasis. The technical obstacles which delayed too long the achievement of reasonably safe and anatomically complete resections of lung are discussed, and the circuitous route trod by pioneering surgeons in their struggle toward that desired goal is described. In addition, some contributions made along the way by members of the faculty at the Yale University School of Medicine to our present knowledge of bronchiectasis--its pathologic anatomy, pathophysiology, and surgical therapy--are summarized briefly.