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I Franke

Publications and source records attributed to I Franke.

35 records · Page 2Linked to original sources
PubMed1997

Purification of a head-activator receptor from hydra.

Head activator (HA) is a neuropeptide conserved from hydra to humans. It acts in the development of neuronal cells and is, in hydra, an important factor in head regeneration. Here we report the solubilization and purification of one head activator receptor (Kd approximately 1 nM) from a multiheaded mutant of Chlorohydra viridissima using HA affinity chromatography. Functional solubilization of the HA receptor from hydra membranes was best performed with Triton X-100 or Chaps. The addition of salt or urea and the protein concentration were important parameters in determining the yield of solubilized receptor. For affinity chromatography HA was coupled to Sepharose. The length of the spacer was optimized with respect to binding of the solubilized HA receptor. After rigorous washing a 200-kDa protein was eluted from HA Sepharose but not from control Sepharoses coupled to bradykinin or without peptide. Ligand binding was preserved in the eluate from the HA Sepharose, and a 200-kDa protein could be photoaffinity labeled. The 200-kDa protein was shown to be glycosylated mainly of the N-linked type. By Edman degradation of the purified protein sequence information was obtained for the N-terminus and after protease digestion for several internal peptides.

Amino Acid Sequence↗
PubMed1997

[Multiple sleep latency test in patients with obstructive snoring].

The objective of our study was to examine the effect of the n-CPAP on day tiredness of patients suffering from obstructive snoring. This effect was objectified by means of the Multiple Sleep Latency Test (MSLT). The MSLT was performed with optimal pressure at 8.00, 10.00, 12.00 and 14.00 hrs. subsequent to the control night and the third CPAP night. The latencies of falling asleep and the sleep stages were determined in accordance with the criteria of Rechtschaffen and Kales. The average latency of falling asleep before therapy was: at 8.00 hrs 9.0 +/- 14.2 min, at 14.00 hrs. 7.2 +/- 6.3 min. The following latencies of falling asleep were observed after the third CPAP night: 8.00 hrs. 14.2 +/- 6.3, 10.00 hrs. 13.4 +/- 6.4, 12.00 hrs. 13.7 +/- 6.4 hrs. 13.7 +/- 6.0 min. This means that after the therapy there was a marked tendency to longer latencies at all 4 points of measurement with significant differences at 12.00 and 14.00 hrs. A comparison of the quality of sleep before and after the therapy yielded an increase in deep sleep and a significant increase in REM density during dream sleep. MSLT enabled objectivation of improved sleep quality and of subjective decrease in day tiredness after CPAP therapy in patients with obstructive snoring. The latency in falling asleep increased at all the points of measurement. Nevertheless, interindividual differences are great, compared with the uniform subjective success of CPAP therapy achieved with these patients.

Adult↗
PubMed1996

Analysis of the reaction mechanism of the non-specific endonuclease of Serratia marcescens using an artificial minimal substrate.

We have studied the mechanism of action of the Serratia nuclease using deoxythymidine 3',5'-bis-(p-nitrophenyl-phosphate) as a substrate. A comparison of the activity with which the wild-type enzyme and several mutant enzymes attack this artificial substrate and herring sperm DNA, respectively, supports the suggestion that His89 is the general base and a Mg2+ ion bound to Glu127 the general acid in the mechanism of phosphodiester bond hydrolysis by the Serratia nuclease, and that Asn119 directly participates in catalysis, for example by transition state stabilisation. Arg57, Arg87 and Arg131, essential for nuclease activity, are not needed for cleavage of the artificial substrate, suggesting that they are involved in binding and positioning of nucleic acid substrates.

DNA↗
PubMed1994

[Topical therapy of extramammary Paget's disease].

A case of locally extensive perigenital Paget's disease in an 84-year-old man is presented. Topical application of 5-fluorouracil emerged as the safest and most effective treatment because of the patient's poor general condition and the extensive involvement of the pubic and genital skin.

Administration, Topical↗
PubMed1985

N-Ethyl-17(R,S)-methyl-(6aR,10aR)-delta 8-tetrahydrocannabinol-18-oic amide. Brain pharmacokinetics in mice, triglyceride/phospholipid partitioning and generalization to the discriminative stimulus properties of delta 9-THC in rats.

The title compound, designed as a model for the affinity moiety of a cannabinoid affinity gel was synthesized in tritiated form (sp. act. 7.27 mCi/mmole). To validate the affinity approach to isolate the putative THC receptor, the properties of the amide were studied. Upon i.p. injection in mice the amide reaches peak brain levels of 0.13% of the total dose after 15 min. Following i.v. injection, maximal brain concentrations of 1.9% are observed at 5 min. Compared to delta 9-THC, which distributes almost equally between triglyceride and phospholipid phases (51:49) the amide exhibits a strong preference for phospholipids (5:95) that can be interpreted as high relative membrane affinity. In rats trained in a water maze to discriminate between i.p. injections of 3 mg/kg delta 9-THC (ED50 = 1.8 mg/kg) and its vehicle, the amide was generalized to the training drug, being five times less potent (ED50 = 8.7 mg/kg) than delta 9-THC. This demonstration of cannabis-like activity indicates that the amide retains affinity to the postulated receptor and justifies the choice for the affinity ligand.

Animals↗
PubMed1985

[Postoperative complications following gynecologic operations in elderly females with benign and malignant changes of the genitals].

The retrospective study reported here, which covered 2116 patients operated on, indicates that postoperative complications are more likely to occur in women aged over 60 than in younger patients. There is also a connection between the patient's age and previous internal disease, the surgical approach, and the severity of the change requiring surgery. The connection between age and postoperative complications is principally explained by previous internal disease. Patients with malignant tumors are at greater risk than women with benign genital changes. Carcinoma cases apart, these patients are older and have suffered more from previous internal disease. While postoperative morbidity and mortality rates are higher among older patients, the percentage of complications occurring is so low that age does not represent a contraindication to gynecological surgery.

Adolescent↗
PubMed1978

Morphometric investigations on endocrine glands. IV. The rat thyroid during liver regeneration after partial hepatectomy with and without application of carcinogenic substances.

Morphometric studies and counting of mitoses in thyroids during regeneration after partial hepatectomy had the following results: 1. During the first days after surgical operation laparotomy caused only a slight reduction of the thyroid function. 2. Up to the 3rd day and especially on the 10th day after partial hepatectomy there is a higher relative percentage of the epithelium in the thyroid, but the mitoses are diminished. 3. Prefeeding with methylnitrosourea and acetylaminofluorene before the surgical 2/3 removal of the liver was answered with subactive thyroids on the 3rd day.

2-Acetylaminofluorene↗