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Biomedical subjects

J Zimmermann

Publications and source records attributed to J Zimmermann.

At least 109 records · Page 6Linked to original sources
PubMed1989

Direct genomic fluorescent on-line sequencing and analysis using in vitro amplification of DNA.

In vitro amplification of genomic DNA and total RNA, as well as recombinant DNA, using one fluorescently labelled and one unlabelled primer during amplification, together with on-line analysis of the products on the EMBL fluorescent DNA sequencer, is described. Further is reported direct sequencing of fluorescently labelled amplified probes by solid-phase chemical degradation, without subcloning and purification steps involved. At present up to 350 bases in 4 hours are determined with this technique. The fluorescent dye and its bond to the oligonucleotide are stable during the amplification cycles, and do not interfere with the enzymatic polymerization. High sensitivity of the detection device, down to 10(-18) moles, corresponding to less than 10(6) molecules makes possible analyses of the non-radioactive amplified probes after only 10 amplification cycles, starting with about 5 x 10(4) copies of recombinant DNA.

Autoanalysis↗
PubMed1989

Automated Sanger DNA sequencing with one label in less than four lanes on gel.

Novel Sanger dideoxy sequencing with only one fluorescent dye label for the four bases of one clone and sequence determination in two lanes on polyacrylamide gel is presented, loading A greater than G in one lane and T greater than C in the other. Sequencing reactions for the two bases in each lane are carried out in one tube. At present the ratio of ddATP:ddGTP and ddTTP:ddCPT is set to 5:1 in the two tubes. Distinction between the two bases in one lane is done by comparing the different magnitudes of the peaks. This method increases the capacity since more clones may be run simultaneously on one gel, while keeping the reliability and simplicity that comes with the use of only one fluorescent dye for the four bases of one clone. At present about 200 bases are determined with the one-dye two-lane method on the EMBL's automated fluorescent DNA sequencer, using T7 DNA polymerase. The error rate in the deduced sequence is about 1%. The technique is used for the determination of overlaps in mapping projects. In principle, it is possible to determine the sequence with one dye in only one lane on the gel by choosing the proper ddNTP ratios for all four bases, carrying out reactions in one tube and applying the product in one lane, but the error rate for this one-lane method seems too high at present and further improvements in the uniformity of peaks obtainable with the T7 DNA polymerase or other enzymes are required.

Base Sequence↗
PubMed1988

Automated Sanger dideoxy sequencing reaction protocol.

The protocol for Sanger dideoxy chain termination reactions in DNA sequencing is tedious and prone to errors due to the repetitive character of the pipetting steps. An industrial robot, with the addition of a few simple parts, was programmed to automate the dideoxy sequencing reactions. The system is set up in a short time for routine operation and it is faster and more reliable than a human operator. It is flexible and allows variations and optimization of the standard procedure. Disposable microtiter plates at a controlled temperature are used. In one reaction cycle (about 50 min) up to 48 templates are processed. Up to 450 bases were resolved in automated DNA sequencing on samples prepared by the robot. The protocol is applicable to fluorescent as well as to radioactive labeling.

Autoanalysis↗
PubMed1988

Oligoclonal bands in serum and cerebrospinal fluid of patients with HIV infection.

Matched samples of serum and cerebrospinal fluid (CSF) from 15 human immunodeficiency virus (HIV)-infected patients were examined after isoelectric focusing. The appearance of oligoclonal bands only in the CSF could indicate the primary HIV infection of CNS in early stages of the disease. Later, the increasing number of autochthonous oligoclonal bands in the CSF suggested locally synthesized IgG against opportunistic infections. Because of the immunodeficiency, T cell independent polyclonal B cell stimulation might mask the oligoclonal pattern.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Characteristics of cellular immune responses to collagen type I or collagen type II.

We have examined the murine cell-mediated immune (CMI) response to collagens type I (CI) and type II (CII) as measured by in vivo delayed-type hypersensitivity responses. We have verified the histopathology and kinetics of the cell-mediated immune responses. Predominant cell-mediated responses were obtained 7, 10, or 14 days following immunization. A presumed antibody-mediated reaction was observed at later times (e.g., greater than 21 days following immunization). The CMI responses to the collagens show a strain-dependent relationship. For CI, the CMI response profile shows H-2b greater than or equal to H-2k = H-2q much greater than H-2d. For bovine CII, the response profile is H-2d greater than H-2b = H-2k = H-2q; the chick CII response profile is H-2q = H-2k greater than H-2b = H-2d, and in limited testing, only the H-2q strain could generate murine CII-specific cell-mediated immune responses. The CII-specific CMI response is cross-reactive with CII from several species of animals, but not with CI. Further, the collagen-specific CMI response can be elicited with certain cyanogen-bromide fragments of bovine CII. Finally, our study also demonstrates that there is a non-H-2-linked locus(i) involved in the development of CII-induced arthritis.

Animals↗
PubMed1983

Adrenergic regulation of sodium and chloride transport in the isolated cornea of rabbit and man.

Isolated corneas were mounted in Ussing-Zerahn-type chambers and short circuit current (SCC) was measured before and after application of drugs (5 X 10(-5) mol X 1(-1)) interfering with adrenergic receptors. Epinephrine increased SCC in the rabbit cornea and decreased SCC in the human cornea. alpha-Adrenergic stimulation or inhibition did not affect SCC. The increase in SCC observed after terbutaline (beta 2-agonist) was similar to the increase after isoproterenol (beta 1- and beta 2-agonist). SCC was not influenced by the beta 1-antagonist atenolol but was modified, although differently in rabbit and man, by the beta 1- and beta 2-antagonist propranolol. Thus, the catecholamine response of the rabbit and human cornea is mainly mediated by beta 2-adrenergic receptors. However, species differences were observed when testing the effect of propranolol on the transcorneal flux of 22Na and 36Cl. In the rabbit cornea the net Cl flux (directed from the aqueous to the tear side) was inhibited by propranolol, whereas net Na flux (from the tear to the aqueous side) was not influenced by the drug. In the human cornea propranolol reduced unidirectional Na flux from the aqueous to the tear side. Thus, the regulatory effect of propranolol on corneal transparency is different in man and the rabbit.

Adrenergic beta-Agonists↗
PubMed1982

Ribosomal recessive suppressors cause a respiratory deficiency in yeast Saccharomyces cerevisiae.

Recessive suppressor mutations in yeast Saccharomyces cerevisiae alter a component of the cytoplasmic ribosomes, relaxing the control of translational fidelity. As a consequence ribosomes can misread nonsense codons as amino acids (Surguchov et al. 1980a). The suppressor mutants are often respiratory deficient, being unable to grow on non-fermentable substrates. The study of the cytochrome spectra has revealed that the cytochrome b and aa3 contents were lower in the mutants than in the parent strains. Furthermore, the suppressor mutations often cause hypersensitivity to paromomycin and neomycin on media with a non-fermentable source of carbon. Some of the suppressor mutants exhibited both erythromycin and chloramphenicol-dependent growth on media containing ethanol or glycerol as a sole carbon source. These results suggest that the mutations altering cytoplasmic ribosomes may simultaneously impair the mitochondrial translation. A coupling of cytoplasmic and mitochondrial protein synthesis in yeast cells is proposed. The existence of a common protein component participating both in mitochondrial and cytoplasmic protein synthesis apparatus is discussed.

Cytochromes↗
PubMed1981

[Chemotherapy of transplanted neurogenic tumors in the rat (author's transl)].

1. After s.c. and intracerebral (i.c.) inoculation, 4 neurogenic tumors of the rat (3 malignant neurinomas, 1 polymorphcellular glioma) revealed an altogether weak response towards a monotherapy with 1,3-bis(2-chloroethyl)-1-nitrosourea(BCNU), 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), 1-(2-chloroethyl)-3-(4-Methylcyclohexyl)-1-nitro sourea (MeCCNU), 1-(2-hydroxyethyl)-3-(2-chloroethyl)-3-nitrosourea (OH-ethyl-CCNU), 2-[3-(2-chloroethyl)-3-nitrosoureidol]-D-glucopyranose (chlorozotocin), 5-(3,3-dimethyl-1-triazeno)-imidazol-4-carboxamide (DTIC). Cyclophosphamide (CPA) which was investigated for comparison showed the greatest therapeutic activity; in an equitoxic dosage (less than or equal to LD10), in all 4 s.c. tumors, partial or complete regression were effected only by CPA. 2. If the passage number increases, the response of transplanted neurogenic rat tumors to monochemotherapy can both increase and decrease. 3. In the monotherapy of 3 malignant neurinomas we were unable, on the whole, to observe a higher sensitivity after s.c. inoculation as compared with an i.c. inoculation of the tumor, despite a varying effectiveness of the single substances. 4. In the monotherapy of the polymorphcellular glioma a better response of the i.c. inoculated tumor was recognizable compared to the s.c. inoculated tumor. 5. A combination chemotherapy of a malignant neurinoma after s.c. and i.c. inoculation with vincristine, CPA, OH-ethyl-CNU and MeCcNU yielded a significant increase in life-span of animals with i.c. tumor, whereas s.c. tumors showed no significant growth inhibition. y. Transplanted neurogenic tumors of the rat could serve at less sensitive models for the investigation of new nitrosoureas.

Animals↗
PubMed1978

Identification of Escherichia coli and Bacillus stearothermophilus ribosomal protein binding sites on Escherichia coli 5S RNA.

E coli [32P]-labelled 5S RNA was complexed with E. coli and B. stearothermophilus 50S ribosomal proteins. Limited T1 Rnase digestion of each complex yielded three major fragments which were analysed for their sequences and rebinding of proteins. The primary binding sites for the E. coli binding proteins were determined to be sequences 18 to 57 for E-L5, 58 to 100 for E-L18 and 101 to 116 for E-L25. Rebinding experiments of purified E. coli proteins to the 5S RNA fragments led to the conclusion that E-L5 and E-L25 have secondary binding sites in the section 58 to 100, the primary binding site for E-L18. Since B. stearothermophilus proteins B-L5 and BL22 were found to interact with sequences 18 to 57 to 100 it was established that the thermophile proteins recognize and interact with RNA sequences similar to those of E. coli. Comparison of the E. coli 5S RNA sequence with those of other prokaryotic 5S RNAs reveals that the ribosomal proteins interact with the most conserved sections of the RNA.

Base Sequence↗
PubMed1978

Binding sites of E. coli and B. stearothermophilus ribosomal proteins on B stearothermophilus 5S RNA.

The primary binding sites for Bacillus stearothermophilus proteins B-L5 and B-L22 and the Escherichia coli proteins E-L5, E-L18 and E-L25 on B. stearothermophilus 5S RNA were determined by limited ribonuclease digestion of the corresponding 5S RNA-protein complexes. The results obtained in this study are in agreement with our previous experiments in which the binding sites of E. coli and B. stearothermophilus proteins were determined for E. coli 5S RNA and lead to the conclusion that the proteins interact with the most conserved regions of 5S RNA. A comparison of the results obtained in this study with those of other published experiments suggest that the proposed interaction of nucleotides 16-21 with those of 58-63 is facilitated by protein binding to 5S RNA.

Bacterial Proteins↗
PubMed1977

Adrenoleukodystrophy (Siemerling-creutzfeldt disease): Heterozygote with two clonal fibroblast populations.

On the fifth day after subcultivation,, fibroblasts of two unrelated patients with adrenoleukodystrophy (Siemerling-Creutzfeldt disease (SCD)) developed typical morphologic anomalies which could be seen by light microscopy. From skin biopsy material of an obligatorily heterozygous womam, both normal and morphologically defective colonies could be isolated. These findings suggest that the morphologic alterations are an expression of the defect in Siemerling-Creutzfeldt disease. Futhermore, they suggest that the SCD locus is subject to lyonization.

Adrenal Cortex Diseases↗
PubMed1977

Sodium etidronate in the treatment of Paget's disease of bone. A study of long-term results.

Subjects (109) with symptomatic Paget's disease of bone were treated with 5, 10, or 20 mg of sodium etidronate (EHDP)/kg body weight - day for 6 to 24 months. Significant decreases in serum alkaline phosphatase and urinary hydroxyproline were noted after 6 months of therapy; no significant further improvement resulted after prolonged therapy. Some patients maintained biochemical remission after withdrawal of EHDP but others showed a relapse, related primarily to the pretreatment severity. Clinical improvement was noted in 61% of the patients. Similar findings were seen after a second course of EHDP. No side-effects were noted in patients treated with 5 mg of EHDP/kg body weight - day. In patients treated with 10 or 20 mg of EHDP/kg body weight - day, severe diarrhea, bone pain, and nontraumatic fractures were noted in 3, 13, and 12 patients respectively. Quantitative histomorphometry showed mineralization delay in patients receiving 10 or 20 mg of EHDP/kg body weight - day but not in those receiving 5 mg/kg body weight - day. Five milligrams of EHDP/kg body weight - day was effective and appears to be safer than the higher doses.

Adult↗