Sulfazecin and isosulfazecin, novel beta-lactam antibiotics of bacterial origin.

In the long history of screening for antibiotics, fungi and actinomycetes have been the only producers of beta-lactam antibiotics although several phytopathogenic bacteria have been reported to produce toxins with a beta-lactam structure. We report here the first evidence that novel monocyclic beta-lactam antibiotics, sulfazecin and isosulfazecin, are produced by new species of Pseudomonas.

Amygdaloid kindling enhances the enkephalin content in the rat brain.

Established amygdaloid kindling causes an increase in the immunoassayable content of both Leuenkephalin and Met-enkephalin in the rat brain. Control and sham-operated (electrode implanted but not stimulated) rats do not show statistically significant differences in brain enkephalin content, while kindled rats show a 40% enkephalin increase in both hemispheres. The present finding is in agreement with several lines of evidence and suggest that enkephalins may play a role in epileptic seizures.

Dnacins, new antibiotics II. Isolation and characterization.

Dnacins A1 and B1, new basic antibiotics with strong and broad antibacterial activities, were isolated as dark red or reddish brown needles from the culture broth of Nocardia sp. No. C-14482.

C-19393 S2 and H2, new carbapenem antibiotics. II. isolation and structures.

Two new beta-lactam antibiotics, C-19393 S2 (1) and H2 (2), were isolated from the culture filtrate of Streptomyces griseus subsp. cryophilus nov. subsp.

Macbecins I and II, new antitumor antibiotics. II. Isolation and characterization.

New antitumor antibiotics, macbecins I and II, were isolated from the culture broth of Nocardia sp. No. C-14919.

In vivo interaction between steroidal alkylating agents and oestrogen receptors in rabbit uteri.

The binding of steroidal alkylating agents to specific tissue component is necessary for the selective distribution of these compounds to their target tissues. The in vivo interaction of Estracyt or NSC-112259 with oestrogen receptors may play an important role in their action mechanism. Both Estracyt and NSC-112259 which were administered in vivo, gradually reduced the binding of [3H] oestradiol to cytoplasmic oestrogen receptor in rabbit uteri.

A new assay method for the determination of oestrogen receptors.

A new assay method was developed to determine the quantity of oestrogen cytoplasmic receptors which are capable of associating with acceptor sites on chromatin. The quantity of oestrogen receptor complexes associated with chromatin is of paramount importance in the mechanism of action of oestrogen. This method is based on the specific binding properties of oestrogen to the receptor and on the binding of the complex to chromatin.

Effects of halothane on coronary and systemic circulations, myocardial metabolism and blood flow distribution within the canine heart.

Myocardial metabolism, blood flow distribution within the heart, and coronary and systemic circulations were observed during halothane anesthesia using 15 mongrel dogs. Pao2 and Paco2 were maintained near 100 and 40 torr respectively throughout the study. As arterial halothane content increased, most parameters of systemic circulation were depressed significantly.

Enzymatic hydrolysis of ATP and e-ATP by F-actin.

Enzymatic hydrolysis of e-ATP by F-actin with and without application of sonic vibration at various pHs was investigated and compared with that of ATP. There was no significant difference on enzymatic activity between F-actin-bound e-ADP and F-actin-bound ADP. The hydrolysis rate of e-ATP under sonic vibration decreases monotonically with decreasing pH, similar to that of ATP.