Biomedical subjects
Publications and source records attributed to J Schmidt.
Flavonoids activate nod gene expression in Rhizobium resulting in the synthesis of Nod signals which trigger organogenesis in the host plant. This paper shows that nod-inducers also stimulate the production of the phytohormone IAA (indole-3-acetic acid).
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Murine peritoneal macrophages activated with interferon (IFN)-gamma and lipopolysaccharide (LPS) produce high levels of nitric oxide (NO) and are efficient in killing the intracellular protozoan parasites Leishmania major in vitro. Earlier studies have shown that NO, whose synthesis in murine macrophages is catalyzed by an inducible enzyme NO synthase, plays a major effector role in the host resistance against microbial infection. We now shown that both the NO synthesis and the leishmanicidal activity can be inhibited by prior treatment of the cells with recombinant interleukin 4 (IL4). IL4 treatment had no effect on the binding of IFN-gamma to macrophages but prevented the induction of NO synthase in these cells activated with IFN-gamma and LPS. Since IFN-gamma is produced by murine T helper type-1 (Th1) cells, whereas IL4 is secreted by Th2 cells, these results suggest a novel pathway by which Th2 cells regulate an activity of Th1 cells, namely by inhibiting the induction of NO synthase. These results may also account for the mechanism by which the disease-promoting Th2 cells counteract the host-protective effect of Th1 cells in leishmaniasis and other intracellular parasitic diseases.
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The effects of the novel antiasthmatic/antiallergic compound azelastine on IL-1 beta were investigated in vitro and in vivo. In leukocytes both, intra- and extracellular IL-1 generation stimulated by LPS was inhibited dose dependently. In contrast azelastine did not prevent IL-1 beta-induced immigration of PMNs into the mouse ear. These findings suggest that azelastine is not an IL-1 antagonist but inhibits IL-1 synthesis and/or release in leukocytes.
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Jejunal perfusion was performed in 12 healthy volunteers to evaluate the dose dependent effects of loperamide on intestinal absorption, stimulated secretion and transit. In 6 volunteers intestinal perfusion of the jejunal segment with isotonic NaCl solution was followed by addition of loperamide in increasing doses (2-8 mg.l-1). The volunteers were pretreated with 1 mg.l-1 prostaglandin E2 (PgE2) in the perfusate before addition of 4 mg.l-1 loperamide. Phenolsulphonphtalein (PSP) boluses (2 ml) were given to measure mean transit time (MTT). Loperamide 2 mg.l-1 converted the minor secretion after perfusion with the standard solution (water -145 ml.min-1, Na -0.09 and Cl -0.04 mmol.min-1) to absorption (water 0.93 ml.min-1, Na 0.23, Cl 0.25 mmol.min-1) within 15 min. Higher doses of loperamide did not increase absorption. The addition of PgE2 induced net secretion of water (-4.48 ml.min-1) and electrolytes (Na -0.57, Cl -0.51 mmol.min-1). Loperamide 4 mg.l-1 significantly diminished the PgE2-induced net secretion by approximately 50%. Loperamide dose dependently increased the MTT from 6 (2 mg.l-1) to 13.3 min (8 mg.l-1). MTT was still delayed 60 min after a wash out period (10.5 min). It is concluded that loperamide had a dual effect or intestinal activities stimulating absorption and prolonging intestinal transit time with rising doses.
Employing a simple sawing gauge system in intertrochanteric osteotomies, it is possible to effect "functional pre-bending" of the angled blade plate osteosynthesis in order to achieve better interfragmentary compression and further improve the precision of the standardized AO technique. This new technique may lead to a further reduction of intraoperative and post-operative failures.
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Temporally-limited internal irradiation after incorporation of short-lived bone-seeking radionuclides is a useful experimental tool for the investigation of extrinsic and intrinsic factors which modify the dose dependence of bone tumor risk. Here we describe some of the results obtained in experiments with female mice (mainly NMRI). The future aim of such experiments should be the prediction of risk of late effects using early molecular-biological changes. Molecular-biological descriptions in our model are at present very limited.
Songarosaponin A, B and C isolated from the aerial parts of Verbascum songaricum were shown to be 3-O-[alpha-L-rhamnopyranosyl-(1----4)-beta-D-glucopyranosyl-(1----3)]-[b eta-D-glucopyranosyl-(1----2)-beta-D-fucopyranosyl]-olea-11,13-die ne-3 beta-23,28-triol, 3-0-[alpha-L-rhamnopyranosyl-(1----4)-beta-D-glucopyranosyl-(1----3)]-[b eta-D-glucopyranosyl-(1----2)]-beta-D-fucopyranosyl]-olea-1 1-ene-3 beta-13,23,28-tetrol and 3-O-[beta-D-glucopyranosyl-(1----4)]-[beta-D-glucopyranosyl-(1----3)]-[b eta-D-glucopyranosyl-(1----2)]-beta-D-fucopyranosyl]-13 beta,28-epoxyolea-11-ene-3 beta,23-diol.
The majority of chloroplast ribosomal proteins are encoded in the nuclear genome. In order to characterize these proteins through their mRNA, we have previously constructed a spinach cDNA expression library and raised antisera to several spinach chloroplast ribosomal proteins. Here we describe the immuno isolation of cDNA clones encoding protein L11 and its chloroplast-targeting presequence. The cytoplasmic precursor form of L11 is 224 amino acid residues long (Mr 23,662); the mature L11 and the transit sequence are predicted to be of approximately 159 and approximately 65 residues, respectively. The predicted chloroplast L11 is significantly longer than the E coli L11, but similar (in size) to archaebacterial and yeast cytoplasmic L11. In sequence it is closer to E coli L11 (54% identity) than to the archaebacterial (32%) or yeast (23%) proteins. These results and the conservation of the contexts of the 3 methyl modified residues found in E coli L11 are discussed in the light of the endosymbiont theory and nuclear relocation of the rp/KAJL gene cluster.
Levels of the acetylcholine receptor (AChR) alpha-subunit mRNA were quantified in chick leg muscle, both after section of the sciatic nerve and following electrical stimulation of the denervated leg musculature. Whereas a lag period of approximately 17 h intervenes between the nerve section and the increase in message level, electrical stimulation leads to an immediate decline, which proceeds with a half-life of 3-4 h, similar to the decay induced by treatment with actinomycin D. The asymmetry in the kinetics of activation and repression can be accommodated by several regulatory schemes of which the simplest contains an autocatalytic loop as recently proposed by Changeux (The New Biologist 3: 413-429, 1991).
The transcriptional enhancers of retroviruses that lack an oncogene are important determinants of their oncogenicity. However, no specific cellular transcriptional activator has yet been found to determine the oncogenicity for any of these viruses. The SL3-3 enhancer factor 1 (SEF1) cellular transcriptional activators are expressed preferentially in T lymphocytes. In the SL3-3 murine leukemia virus enhancer, two different sequences can bind SEF1 activators. We show that mutation of the SEF1 binding sites disrupts the disease potential of SL3-3 murine leukemia virus, implying that SEF1 transcriptional activators are required for tumor induction by SL3-3. The SEF1 site mutations did not appear to affect the pathogenicity of SL3-3 by impairment of virus multiplication, but rather by a specific defect in the ability of neoplastic transformation.
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A newly developed 90 degrees angled blade plate that permits high interfragmentary compression with a potential sliding way of 9 mm, is described. In the majority of intertrochanteric osteotomies, and especially when applying "functional pre-bending", the use of an external compression device is not necessary with this plate. The plate consists of 2 modules which permit a temporary thickening of the plate up to 10 mm, and the principle of dynamic compression can be performed with a 45 degree screw hole for the sliding way of 9 mm. The results of testing showed that a compression force of up to 1200 N was possible. The resulting interfragmentary compression could not be increased even with the aid of an external compression device or by idealized experimental conditions. Whenever dynamic compression is necessary for fixation, the modular compression principle described here can be used with any other plate system.
Aflatoxin B1 is suspected as an etiologic factor in the increased risk for primary liver cancer among workers in animal-feed processing plants in Denmark. Aflatoxin bound to serum albumin was therefore measured for feed-processing workers. Blood samples were collected immediately after vacation and after four weeks of work, and aflatoxin was quantified by competitive enzyme-linked immunosorbant assay. Seven of 45 individuals with an estimated exposure of 64 ng aflatoxin B1.d-1.kg-1 body weight were positive. Three positive workers had been unloading a cargo with an aflatoxin B1 level of 26 micrograms.kg-1 raw material. The exposure level correlated well with the job titles. Dust samples collected at different sites showed considerable variation in the amount of aflatoxin B1 (nondetectable to 8 micrograms.kg-1 dust). The exposure to aflatoxin B1 may only partially explain the increased risk of liver cancer.
We describe a novel technique for complete and continuous bladder urine collection in conscious unrestrained rats. After urethral ligation, a silastic catheter is placed through a flexible steel tether, tunneled subcutaneously from the posterior neck area to a suprapubic incision, and inserted and fixed into the exposed urinary bladder. The catheter drains by gravity into a dependent collecting vessel protected from contamination by feces or food.