High Suppression Research Articles

Synthesis, Stability, and Antimalarial Activity of New Hydrolytically Stable and Water-Soluble (+)-Deoxoartelinic Acid

(+)-Deoxoartelinic acid (13), a new hydrolytically stable, water-soluble, and potent non-acetal-type antimalarial drug candidate, was successfully prepared from artemisinic acid by using sulfur ylide and photooxygenative cyclization in seven steps. This compound showed superior in vitro antimalarial activity against the chloroquine-resistant K1 strain of Plasmodium falciparum and higher suppression (98.7%) than arteether in vivo against Plasmodium chabaudi infected mice. (+)-Deoxoartelinic acid also showed remarkable stability with a half-life of 258.66 h, 23 times more stable than clinically useful arteether in simulated stomach acid, and improved solubility, 4 times more soluble than artemisinin in water.

Antimicrobial Activities of Pseudomonads against Plant Pathogenic Organisms and Efficacy of Pseudomonas aeruginosa ATCC7700 against Bacterial Wilt of Tomato.

Numerous strains of pseudomonads formed growth inhibition zones around their colonies which had been placed on lawns of phytopathogenic bacteria and fungi used as indicators. The antimicrobial activity spectra against the indicator bacteria and fungi varied greatly with the species and strain of the pseudomonads, suggesting that various antimicrobial substances participated in the antagonism. Strain ATCC7700 of Pseudomonas aeruginosa was highly antagonistic in vitro to various plant pathogenic bacteria and fungi, especially to Ralstonia solanacearum. Treating of tomato roots with P. aeruginosa at the time of transplanting in R. solanacearum-infested soil increased the percentage of seedling survival. Soaking the root systems of tomato seedlings in a bacterial suspension of ca. 1010 cfu/ml resulted in the highest suppressiveness. Pretreating tomato roots with killed cells of P. aeruginosa also gave protection, suggesting that mechanisms other than antibiotic production, such as induced resistance and infection sites competition were involved in suppression of the disease.

The in vivo Response of J Chain-Positive Cells to B and T Cell Mitogens in Chickens.

Influence of in vivo administration of mitogen, anti-μ or PHA, was examined on the frequencies of J chain-positive cells (JPC) in chicken bursa of Fabricius and spleen. There were increases of cellular size in the bursa and the spleen after the anti-μ injection. This finding suggests the stimulation effect of anti-μ on chicken lymphocytes.The number of bursal JPC decreased on day 2 and then recovered gradually to the control level. Such suppressive effect was again detected in the spleen treated with anti-μ and higher suppression was apparent in the splenic JPC than the bursal one. Therefore, the anti-μ treatment showed suppressive effect on the JPC number of bursa and spleen. After the PHA stimulation, the number of bursal JPC increased on days 2 to 3, then decreased on days 4 and 7. Similar finding was apparent in the splenic JPC. These results suggested the possible participation of T cells in the JPC response after the PHA stimulation.

Postantibiotic Effect and Virulence Factors Depression Induced by Ciprofloxacin and by Aminoglycosides in a Clinical Isolate of Pseudomonas aeruginosa

The postantibiotic effect (PAE) was induced in Pseudomonas aeruginosa by ciprofloxacin, tobramycin and netilmicin (2x or 4x MIC). A longer PAE was evoked by a higher concentration of antibiotics. The evaluation of Pseudomonas aeruginosa virulence factors after treatment with suprainhibitory concentrations of the antibiotics tested showed that a higher suppression of elastase activity was associated with a longer PAE. Elastase was suppressed more effectively than proteinase. The highest reduction of elastase and proteinase activity (to 24.9% and 76.4% of the control values) was observed after treatment with ciprofloxacin.

Recovery functions of early cortical median nerve SSEP components: normative data

The recovery functions of parietal P14-N20, N20-P27 and frontal P22-N30 amplitudes were assessed in 17 healthy controls aged 20–50 years by means of the paired stimulus technique. One unpaired and 4 paired stimuli with interstimulus intervals (ISIs) of 25, 50, 75 and 100 msec were cyclically presented in a single run. Responses to the unpaired stimulus were subtracted off-line from paired stimulus responses. The highest suppression was reached at shorter ISIs for components with shorter latencies. The mean suppression of P22-N30 was influenced by the subject's age, being greater in younger subjects. Normative data are reported.

Decidual-trophoblast interactions: decidual lymphoid cell function in normal, anembryonic, missed abortion and ectopic human pregnancy

This study was designed to investigate the consequences of decidua-trophoblast interactions on the phenotype, spontaneous and induced proliferation and immunoregulatory potential of decidual leukocytes in normal pregnancies (NP), anembryonic pregnancies (AP), missed abortions (MA) and ectopic pregnancies (EP). Spontaneous proliferation of decidual non-adherent cells (NAD) from pregnancies with viable trophoblast inside the uterus is significantly higher than proliferation of peripheral blood lymphocytes (PBL) from the same groups ( P < 0.001 for NP; P < 0.05 for AP). Spontaneous proliferation of decidual NAD cells from NP was higher ( P < 0.001) when compared with AP and EP. The induced (PHA and Con A) responses of PBL from women with normal and pathological pregnancies were significantly higher than that of decidual NAD cells ( P < 0.001). Higher proliferation of NAD decidual cells was obtained when Con A-stimulated NP were compared with MA and EP ( P < 0.01). The interaction of viable trophoblast with intrauterine decidua appears to be a prerequisite for the activation of NAD suppressor cells, since NAD cells from MA produced stimulation instead of suppression, and NAD cells from EP had no suppressive effect. On the contrary, both NAD and adherent (AD) decidual leukocytes from NP and AP produced very strong suppression of PHA or alloantigen-induced PBL proliferation. The contact between trophoblast and AD decidual leukocytes is not necessary for their suppressive function, since even higher suppression is obtained with the cells from ectopic pregnancies.

Effect of dopamine, l-dopa, carbidopa and l-dopa/carbidopa on arthus and delayed hypersensitivity skin reactions in the rat

This study deals with the effects of dopamine (DA), L-dopa, carbidopa and L-dopa/carbidopa on immuno-inflammatory skin reactions in the rat. For this purpose, male Wistar rats immunized with bovine serum albumin in Freund's adjuvant were treated subcutaneously with different doses of DA, L-dopa, carbidopa and L-dopa/carbidopa, for a period of 14 consecutive days or 3 days before skin-testing with BSA. An additional group of rats received 1 injection of a dopamine-related drug 4 hours before and 1 injection 4 hours after skin-testing. Corresponding controls were treated with saline. Arthus and delayed hypersensitivity skin reactions were read at 4 and 24 hours respectively. The results showed that repeated injections of DA, L-dopa and L-dopa/carbidopa significantly suppressed Arthus and delayed reactions. The highest suppression was recorded in rats treated with L-dopa plus carbidopa. Concerning the dose required for immunosuppression it appears that DA was the most effective. Carbidopa did not affect hypersensitivity skin reactions. These results suggest the in vivo relationship between dopamine-related compounds (L-dopa and DA) and immuno-inflammatory reactions. Most probably, L-dopa when is given alone converts into DA and this increase of DA content in periphery depresses immune reactions. However, L-dopa given together with carbidopa (an enzyme which prevents decarboxylation of L-dopa into DA, and enables the penetration of L-dopa into CNS) augments the content of DA in the brain and thus affects immune responses. It appears, therefore, that L-dopa and DA act both peripherally and centrally on immune responsiveness.

Suppression of autoimmune thyroiditis by phytohemagglutinin

The effect of high doses of PHA in autoimmune thyroiditis was studied. The autoimmune response was elicited by the injection of syngeneic thyroglobulin (Tg) followed 3 hr later by LPS on days 0 and 7. PHA was injected 48 and 24 hr before the first antigen administration. The antibody titer to thyroglobulin and the degree of cellular infiltration in the thyroid were determined thereafter. It was found that PHA reduces the humoral response to Tg and completely suppresses the infiltration in the thyroid. However, this suppression is no longer observed 7 weeks later. By testing this effect with CFA instead of LPS, no PHA-induced suppressive effect was seen. The highest suppression is found when PHA is given close to the antigen injection.