Induction of increased antibody responses to pneumococcal type 19F polysaccharide by Klebsiella polysaccharide

The level of antibody to pneumococcal 19F polysaccharide (PS) was studied in the serum of mice inoculated with klebsiella K2 PS or pneumococcal 19F PS or both. The serum antibody levels and the IgM plaque-forming-cell (PFC) response after immunization were higher in mice given both K2 PS and 19F PS than in mice of a control group given 19F PS alone. This immune response was also higher than the sum of PFC production in mice given 19F PS or K2 PS separately. Thus, K2 PS produced the cross-reactive antibody to 19F PS and also enhanced the magnitude of the antibody response to 19F PS. This response appeared to be specific for the 19F PS. The resulting high levels of antibody to pneumococcal 19F persisted for eight weeks after the administration of K2 PS and 19F PS. Animals immunized with both type 3 PS and K2 PS did not show an increased antibody response to pneumococcal type 3 PS. Klebsiella K-O3 antigen also stimulated the immune response to 19F PS. Higher immunologic responses to 19F PS were also induced in nude mice injected with the cross-reacting K2 PS or K47 PS and 19F PS. The ability to stimulate an antibody response to 19F PS by administering both K2 PS and 19F PS could not be transferred with spleen cells obtained from mice given both K2 PS and 19F PS.

Escherichia coli 6S RNA gene is part of a dual-function transcription unit

The gene coding for the metabolically stable 6S RNA of Escherichia coli has been cloned, sequenced, and partially characterized in expression analyses. The DNA sequence results confirm the accuracy of the previously established RNA sequence and, with genomic hybridization data, reveal that there is only one copy of the 6S DNA in the chromosome. Consistent with its relaxed mode of expression, the promoter region of the 6S RNA gene was found to lack the hypothetical GC-rich discriminator domain common to other stable RNA genes under stringent control. The sequence results also revealed the occurrence of a 540-base-pair open reading frame immediately downstream from the 6S RNA coding region. Results from the expression analyses show that the protein and RNA coding regions are cotranscribed in vitro and that the open reading frame is translated in vivo.

Nickel inhibition of calcium release from subsarcolemmal calcium stores of molluscan smooth muscle

Replacement of calcium in artificial sea water (ASW) by nickel causes a loss of calcium at a single exponential rate (tau = 23.2 min) and the loss of contracture response to acetylcholine (ACh) in the anterior byssus retractor muscle of Mytilus edulis L. The ACh contracture response is lost at two rates; 93% of the ACh contracture response is lost rapidly (tau = 7.43 min) and the remaining 7% of ACh contracture response is lost slowly (tau = 66.6 min). The rapid phase of loss of ACh contracture corresponds to the rapid exponential uptake of nickel (tau = 6.5 min). The loss of ACh contracture response is attributed to the displacement of calcium from membrane release sites by nickel. In O-Ca-Mg ASW, the ACh contracture responses are well maintained over a 35-min period when stimulated by ACh every 5 min. Stimulation by ACh after 1, 20 and 40 min in O-Ca-Mg ASW results in a reduction of ACh contracture response to 15% of the response in Ca ASW. Similar treatment in O-Ca-Ni ASW reduces the ACh contracture response to 4%. Potassium and caffeine contracture responses at 1, 20 and 40 min in O-Ca-Mg ASW are reduced to 25 and 28%. Similar treatment in O-Ca-Ni ASW produces a block of potassium contracture response and reduces caffeine contracture response to 3%. Our 45Ca uptake data demonstrate that calcium influx is not required for the ACh contracture responses of anterior byssus retractor muscle.

The effect of a medicinal Chinese herb on platelet function

We investigated the effect of the Chinese herb Injectio Salvia Miltiorrhizae (ISM) on human platelet function in vitro. ISM inhibited platelet aggregation and serotonin release induced by either ADP or epinephrine in a dose dependent manner. This effect of ISM was observed with both gel-filtered platelets (ID50 = 8-30 micrograms ISM/ml gel-filtered platelets) and platelets in plasma (ID50 = 400-900 micrograms ISM/ml of platelet-rich plasma). The active molecule(s) in ISM was heat stable, resistant to acid, base and proteolysis and fractionated on Sephadex 6-25 at MW approximately 280. ISM did not interact with the platelet alpha-adrenergic receptor, but increased cAMP in intact platelets. The results are consistent with the concept that ISM inhibition of platelet aggregation and release is mediated by an increase in platelet cAMP. The exact mechanism whereby ISM increases platelet cAMP appears to be that of inhibition of cyclic AMP phosphodiesterase. The effect of ISM on platelet function is one mechanism which might explain the therapeutic effect of ISM in experimental and clinical coronary artery disease.

The Effect of a Medicinal Chinese Herb on Platelet Function

We investigated the effect of the Chinese herb Injectio Salvia Miltiorrhizae (ISM) on human platelet function in vitro. ISM inhibited platelet aggregation and serotonin release induced by either ADP or epinephrine in a dose dependent manner. This effect of ISM was observed with both gel-filtered platelets (ID50 = 8–30 μg ISM/ml gel-filtered platelets) and platelets in plasma (ID50 = 400–900 μg ISM/ml of platelet-rich plasma). The active molecule(s) in ISM was heat stable, resistant to acid, base and proteolysis and fractionated on Sephadex 6-25 at MW ~ 280. ISM did not interact with the platelet α-adrenergic receptor, but increased cAMP in intact platelets. The results are consistent with the concept that ISM inhibition of platelet aggregation and release is mediated by an increase in platelet cAMP. The exact mechanism whereby ISM increases platelet cAMP appears to be that of inhibition of cyclic AMP phosphodiesterase. The effect of ISM on platelet function is one mechanism which might explain the therapeutic effect of ISM in experimental and clinical coronary artery disease.