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41.
42.
Proximal tubular cells were loaded for 10 s with [3H]para-aminohippurate ([3H]PAH) by microperfusing the peritubular capillaries with Ringer solution containing 0.05 mmol/l PAH. Immediately thereafter
[3H]PAH influx from cells into a column of equilibrium solution injected into the oil-filled tubular lumen was measured by re-aspirating
the fluid after 1–10 s of contact time. The rise of luminal PAH concentration within 2 s of contact time was almost linear,
reaching a luminal / capillary concentation ratio of 1.6 after 2 s and of 3.2 after 5 s. The 2-s PAH concentration ratio was
not changed when different manoeuvres were applied to depolarize proximal tubular cells. Also, the 2-s PAH concentration ratio
was not influenced by varying the luminal pH from 6.0 to 8.0 or the luminal Cl–concentration from zero to 134 mmol/l or when either 5 mmol/l urate or 25 mmol/l lactate was in the luminal perfusate. A decrease
in the 2-s PAH concentration ratio, i.e. trans-inhibition, was observed when 25 or 50 mmol/l HCO3
–(–50%) was in the luminal perfusate. Trans-inhibition was also seen with 5 mmol/l of the following substituted benzoates:
2-hydroxy-benzoate (–58%), 2-methoxy-benzoate (–46%), 2-hydroxy-benzoate-acetyl ester (–36%), 2-hydroxy-3,5-dinitro-benzoate
(–48%), 3,5-dichloro-benzoate (–49%), and 2,3,5-trichloro-benzoate (–45%). No effect was seen with benzoate, 3-hydroxy-benzoate,
2-chloro-benzoate, 2-nitro-benzoate, 2,5-dinitro-benzoate, 3-sulfamoyl-benzoate and 4-sulfamoyl-benzoate. However, analogues
of the latter two compounds possessing two additional side groups, such as furosemide and piretanide, or a hydrophobic moiety,
such as probenecid, were inhibitory (by –62, –41 and –49% respectively). Phenoxyacetate had no effect; however, it inhibited
if in addition it had three chloro groups, as in 2,4,5-trichlorophenoxyacetate (–71%) or a hydrophobic carbamoyl side group,
as in mersalylic acid (salyrgan, –75%). Benzene-sulfonate trans-inhibited (–33%), as did phenolsulfonphthalein (phenol red,
–39%) and sulfofluorescein (–55%). However, the trans-inhibitory effect of the corresponding carboxy-compounds was absent
(phenolphthalein) or weaker (fluorescein, –42%). The trans-inhibitory effect of the uricosurics ethacrynic acid (–53%), tienilic
acid (–55%) indacrinone (–72%) and benzbromarone (–42%) could be attributed to two chloro or bromo side groups on the benzene
ring. Other trans-inhibiting uricosuric substances were indomethacin (–42%), sulfinpyrazone (–38%), losartan (–80%) its metabolite
EXP 3174 (–55%), and AA 193 (–65%). These organic acids, with pKa values between 2.8 and 4.9, possess chloro and sulfin groups, as well as heterocyclic 5-ring and hydrophobic ring or chain
areas. No significant effect was seen with 5 mmol/l PAH, 2-oxo-glutarate, DIDS, cGMP, prostaglandin E2, cortisol, benzylamiloride, pyrazinoic acid and 25 mmol/l lactate. Our data indicate that in situ the secretory luminal PAH
transport proceeds in a non-rheogenic fashion, per exclusionem by anion exchange. The observed trans-inhibition of PAH secretion seems to correlate with the affinity for the luminal PAH
transporter and, for uricosuric substances, with their uricosuric potency.
Received: 15 October 1996 / Received after revision: 17 December 1996 / Accepted: 18 December 1996 相似文献
43.
Sergey M. Kipriyanov Gerhard Moldenhauer Melvyn Little 《Journal of immunological methods》1997,200(1-2):69-77
We have investigated the effect of growth and induction conditions on the production of soluble single-chain Fv antibody fragments in Escherichia coli under the control of wt lac promoter. The scFv was directed into the periplasmic space by a pelB leader sequence. Addition of sucrose to the medium gave a 15–25-fold increase in the yield of soluble scFv-phOx (3.0 mg/l) for bacterial shake-tube cultures and an increase of 80–150-fold (16.5 mg/l) for shake-flask cultures. Using flask culture in the presence of 0.4 M sucrose, a significant amount of scFv was released into the medium. We found that the scFv could be made to accumulate in the periplasm or be secreted into the medium by simply changing the incubation conditions and the concentration of the inducer. The ratio between soluble antibody fragments and insoluble scFv aggregates proved to be dependent on the strength of the promoter. Lowering the incubation temperature below 20°C had no effect on the yield of soluble antibody fragments in the periplasm, but they were no longer secreted into the medium. An example of high level production in shake-flask cultures and one-step purification by immobilized metal affinity chromatography (IMAC) is described for a soluble scFv specific for the T cell surface antigen CD3. The biological activity of the purified anti-CD3 scFv was demonstrated by flow cytometry. This method should be especially useful for the functional screening of a large number of clones in small-scale cultures. 相似文献
44.
St?le Nordg?rd Gerhard Hein Brit Kari Stene Ketil Wichman Skj?stad Joachim T Maurer 《Otolaryngology--head and neck surgery》2007,136(5):818-822
OBJECTIVE: To evaluate long-term effectiveness of palatal implants for treatment of mild to moderate obstructive sleep apnea (OSA). STUDY DESIGN: A prospective study of 26 referred patients with a pretreatment apnea-hypopnea index (AHI) of 10 to 30 and a body mass index of < or =30, representing an extended follow-up of a subset of 41 patients enrolled in previous short-term trials. RESULTS: Twenty-one of 26 patients (80.8%) experienced a decrease in AHI. Fifteen of 26 patients (57.7%) had a follow-up AHI <10 at 1 year, whereas 13 patients (50%) had a 50% or greater reduction to an AHI <10 at 1 year. Mean AHI was reduced from 16.5 +/- 4.5 at baseline to 12.5 +/- 10.5 at 3 months (P < 0.014) and to 12.3 +/- 12.7 at 1 year (P < 0.019). CONCLUSIONS: Patients initially responding to palatal implants with improved AHI maintained improvement through long-term follow-up at 1 year. 相似文献
45.
Phenytoin–lipid conjugates obtained by covalent binding of hydroxymethylphenytoin to diacylglycerides and to 3-acyloxy-2-acyl-oxymethylpropionic acids formed dispersions with a particle size of 10–200 µm when briefly sonicated in a sodium taurodeoxycholate-containing ethanol–water mixture. In contrast to the corresponding bis-deacyl derivatives, the lipids were not significantly hydrolyzed in aqueous buffers and in plasma. Incubation with pancreatic lipase yielded primarily the bis-deacyl compounds, which are comparable to monoglycerides, and subsequently liberated phenytoin. The glyceride-derived prodrugs were better substrates for the enzyme than the 3-acyloxy-2-acyloxymethyl-propionic acid derivatives. It is concluded that the phenytoin lipid conjugates are hydrolyzed by pancreatic lipase in a similar manner as natural triglycerides. 相似文献
46.
47.
48.
Claudia Ladner Gerhard Ehninger K. Fred Gey Michael R. Clemens 《Cancer chemotherapy and pharmacology》1989,25(3):210-212
Summary A total of 13 patients receiving bone marrow transplants (BMT) for treatment of different haematological diseases were investigated. Conditioning therapy preceding BMT consisted of fractionated total-body irradiation (12 Gy) and high-dose chemotherapy with cyclophosphamide (2±60 mg/kg). Patients stratified to be at high risk for relapse (6/13) were additionally treated with etoposide (30 mg/kg). Plasma concentrations of absolute and lipid-standardized antioxidants (-tocopherol and -carotene) decreased following conditioning therapy, presumably as the result of an enhanced breakdown of these antioxidants. Etoposide treatment did not amplify the loss of essential anti-oxidants but significantly increased lipid hydroperoxide concentrations in serum. We suggest that the abnormal generation of lipid hydroperoxides is the result of free radical formation. 相似文献
49.
Functional analysis of the cag pathogenicity island in Helicobacter pylori isolates from patients with gastritis, peptic ulcer, and gastric cancer 总被引:9,自引:0,他引:9 下载免费PDF全文
Backert S Schwarz T Miehlke S Kirsch C Sommer C Kwok T Gerhard M Goebel UB Lehn N Koenig W Meyer TF 《Infection and immunity》2004,72(2):1043-1056
Helicobacter pylori is the causative agent of a variety of gastric diseases, but the clinical relevance of bacterial virulence factors is still controversial. Virulent strains carrying the cag pathogenicity island (cagPAI) are thought to be key players in disease development. Here, we have compared cagPAI-dependent in vitro responses in H. pylori isolates obtained from 75 patients with gastritis, peptic ulcer, and gastric cancer (n = 25 in each group). AGS gastric epithelial cells were infected with each strain and assayed for (i) CagA expression, (ii) translocation and tyrosine phosphorylation of CagA, (iii) c-Src inactivation, (iv) cortactin dephosphorylation, (v) induction of actin cytoskeletal rearrangements associated with cell elongation, (vi) induction of cellular motility, and (vii) secretion of interleukin-8. Interestingly, we found high but similar prevalences of all of these cagPAI-dependent host cell responses (ranging from 56 to 80%) among the various groups of patients. This study revealed CagA proteins with unique features, CagA subspecies of various sizes, and new functional properties for the phenotypic outcomes. We further showed that induction of AGS cell motility and elongation are two independent processes. Our data corroborate epidemiological studies, which indicate a significant association of cagPAI presence and functionality with histopathological findings in gastritis, peptic ulcer, and gastric cancer patients, thus emphasizing the importance of the cagPAI for the pathogenicity of H. pylori. Nevertheless, we found no significant association of the specific H. pylori-induced responses with any particular patient group. This may indicate that the determination of disease development is highly complex and involves multiple bacterial and/or host factors. 相似文献
50.