Histamine contraction of isolated human airway muscle preparations: role of prostaglandins.

Histamine concentration-effect curves were obtained using either an individual or cumulative dosing method. The maximal response to histamine in bronchial preparations using the individual dosing protocol was 0.25 +/- 0.

[Synthesis of paf-acether by E. coli K12].

Paf-acether (platelet-activating factor) is one of the most potent mediator of inflammation released from and acting on most cells that participate in inflammatory diseases. Its molecular structure is 1-O-alkyl-2-O-acetyl-sn-glycero-3-phosphocholine. Two metabolic steps are involved in its biosynthesis: the action of a phospholipase A2 on choline-containing membrane alkyl-ether lipids results in the production of lyso paf-acether and acetylation of the lyso compound by an acetyltransferase yields the biologically active molecule.

Response and sensitivity of isolated human pulmonary muscle preparations to pharmacological agents.

The responsiveness (grams per millimeter squared) and sensitivity (pD2 value) of various agonists were examined in isolated stored human bronchial and pulmonary arterial and venous preparations. In isolated bronchial muscles, large preparations (internal diameter about 6 mm) were less responsive (grams per millimeter squared) to contractile agents than smaller preparations (internal diameter approximately 2 mm). Noncumulative concentration-effect curves were produced in bronchial preparations using histamine, acetylcholine, carbachol and barium chloride.

Chlamydia psittaci experimental abortion in goats.

To study abortive chlamydiosis in goats, 11 pregnant goats were inoculated intradermally at the 3rd month of pregnancy with 2 X 10(7) or 2 X 10(6) plaque-forming units of a strain of Chlamydia psittaci isolated from naturally occurring abortions in goats. The 11 inoculated does aborted 24 to 56 days after they were inoculated and shed Chlamydia. This shedding began at least 9 days before abortion (1 goat) and persisted 12 days after abortion (1 goat).

The actions of Paf-acether (platelet-activating factor) on guinea-pig isolated heart preparations.

Paf-acether (platelet-activating factor) is a phospholipid capable of stimulating platelets to release their granular contents and cause platelet aggregation. When Paf-acether was administered to isolated heart preparations from normal guinea-pigs there was a significant concentration-dependent reduction in coronary flow and contractile force. The high concentration of Paf-acether was equally effective in reducing these cardiac parameters in the presence of atropine.