Stimulation of sodium transport by antidiuretic hormone in bullfrog intestine.

Antidiuretic hormone (ADH) increased the potential difference (PD) and shortcircuit current (SCC) across the small intestine of the bullfrog. This effect was independent of those produced by amiloride or high calcium but was masked by a theophylline-induced effect. Net active sodium (Na+) absorption accounted for the observed electrical changes.     

Presumptive identification of aminoglycoside antibiotics by the pH susceptibility disc agar-diffusion method.

Using the pH (buffered) sensitivity discs for the agar-diffusion bioassay of aminoglycoside antibiotics, characteristic response curves were obtained. Since the nature of the activities observed are structure-related, this method can serve as a useful aid for primary identification of members of this class of antibiotics.     

Haemoglobin Bohr effect and lactic acid content of the blood of 2 water-snakes with different degrees of aquatic adaptation.

H. modestus, a water-snake with morphological respiratory adaptation to its habitat, presents haemoglobins with a lower Bohr effect than those of L. miliaris, an aquatic snake without such respiratory adaptations. The difference in blood lactic acid content of the 2 snakes submitted to mechanical stimuli appears to be compatible with the properties of their haemoglobins.     

An adrenergic participation subserving a positive inotropism and chonotropism of prostacyclin on isolated rat atria.

The effects of prostacyclin (PGI2) on the contractile frequency and on the isometric developed tension of spontaneously beating or paced isolated rat atria were explored. PGI2 enhanced frequency and contractile tension, both effects being blocked by the presence of propranolol, or following a pretreatment with 6-OHDopamine.     

Somatostatin content and release of isolated pancreatic islets from obese-hyperglycemic mice.

The somatostatin content in pancreatic islets of obese-hyperglycemic mice was much lower than in the islets of normal mice. Also the release of somatostatin was decreased from the islets obtained from the obese-hyperglycemic mice. Tissue culture for 1 week changed neither the content of, nor the amount of somatostatin released from, the pancreatic islets.     

Complexed rheumatoid factor measurements in sera, synovial fluids and in immune complex fractions.

Mild acidic treatment increases the rheumatoid factor titre of some sera and synovial fluids (SF) in rheumatoid arthritis (RA), juvenile RA (JRA) and most frequently in rheumatoid vasculitis. This unmasking of 'hidden' RF in serum and SF samples correlated with the RF-immune complexes (RF-IC) and complexed C4 present in the 3% polyethylene glycol (PEG) precipitates, indicating that by means of 'hidden' RF measurements RF-ICs are possibly detected. This method seems to provide a diagnostic tool for detecting RF-ICs in RA and other related diseases.     

Influences of temperature change on the relaxation and amplitude inhibition by noradrenaline in the rabbit jejunum.

In the rabbit jejunum, the elevation of temperature within the range of 25-37 degrees C diminished the sensitivity to noradrenaline (NA) for both the relaxation and amplitude inhibition. The relaxation by NA was mainly mediated via adrenergic beta-receptors at 25, 30 or 37 degrees C. The amplitude inhibition was mediated via alpha-receptors at 37 degrees C, and both alpha- and beta-receptors at 30 or 25 degrees C.     

Control of the hypothalamus-pituitary-adrenal axis in young and older rats injected with thyroxine.

Administration of T4 on alternate weeks for 30 weeks at a dosage which does not alter body weight depresses basal serum corticosterone levels in older rats (575 days), but not in young animals (260 days). Similar serum corticosterone response to HPA axis stimulation occurs regardless of age or T4 injection.     

Role of ACTH on the cytomorphology of testes of the immature rat.

The male gametogenic development of the immature rat shows inhibitory effect by the exogenous infusion of ACTH (0.25 IU and 0.50 IU; i.p.). Seminiferous tubular degeneration, Leydig cell atrophy and Sertoli cell regression are very conspicuous in the dosage of 0.50 IU ACTH (i.p.). Cytometrical and histological evidence confirms that ACTH could be inhibited by FSH during male gametogenic development which leads to cellular degeneration of testes in the immature rat.     

Tangential flow filtration of Bordetella pertussis submerse cultures.

A procedure is reported for the large scale separation of Bordetella pertussis microorganisms from liquid culture media by tangential flow filtration (cross flow filtration) using anisotropic membranes with a cut-off limit of 1 x 10(6) daltons, and microporous membranes with a pore size of 0.22 micrometer.