PubMed Health⌕ Search

Biomedical subjects

H Körner

Publications and source records attributed to H Körner.

At least 91 records · Page 5Linked to original sources
PubMed1987

Immunochemical patterns of distribution of nitrous oxide reductase and nitrite reductase (cytochrome cd1) among denitrifying pseudomonads.

The novel multicopper enzyme nitrous oxide reductase from Pseudomonas perfectomarina was purified to homogeneity to study its properties and distribution in various pseudomonads and other selected denitrifying genera by immunochemical techniques. Quantitation of immunochemical crossreactivity by micro-complement fixation within the denitrifying pseudomonads of Palleroni's ribosomal ribonucleic acid group I corresponded to the taxonomic positions established by nucleic acid hybridization. The assignment of P. perfectomarina to the stutzerigroup (as strain ZoBell) was consolidated by immunochemical crossreactivity based on nitrous oxide reductase. Crossreactivity of nitrite reductase (cytochrome cd1) with a respective P. perfectomarina rabbit antiserum was limited to strain DSM 50227 of P. stutzeri; although it could not contribute information towards broader relationships within rRNA group I, it lent further prove to the unity of these two species.

Complement Fixation Tests↗
PubMed1986

Maternal serum alpha-fetoprotein screening for neural tube defects and other disorders using an ultramicro-ELISA. Collaborative study in Cuba and in the German Democratic Republic.

In Cuba and in the German Democratic Republic (GDR) a total of 24,412 pregnant women were tested for maternal serum alpha-fetoprotein (MSAFP) at the 16th to 20th week of gestation. An inexpensive and partly automated ultramicroliter enzyme immunoassay (ELISA) with final volumes of 10 microliter was used to analyze simultaneously 50 samples. The intraassay coefficient of variation (CV) of 5-8% and day/day CVs of 6-10.5% were obtained with a test frequency of 320 assays/day. A cut-off level of twice the median value (MoM) was chosen. An amniocentesis was done in a total of 0.5% (in the GDR) and 0.7% (in Cuba) of the screened women. The prevalence of open neural tube defects (ONTD) was calculated from the present study and was 1.43% in Cuba and 1.34% in the GDR. Through MSAFP screening 88.2% ONTD were detected. There was no therapeutic abortion of a normal fetus. The approximate cost for this program was about 2.36 marks-GDR per patient screened, or about 2,048 marks per ONTD detected.

Abortion, Spontaneous↗
PubMed1986

The follicular phase stimulated by human pituitary gonadotropin and the luteal phase following in vitro fertilization.

The pattern of follicular and luteal phase levels of serum estradiol-17 beta (E2) and progesterone (P) are compared between 5 conception (group P) and 27 nonconception (group N) cycles of patients undergoing in vitro fertilization and embryo transfer. Follicle growth was induced with human pituitary gonadotropin and controlled by daily ovarian ultrasonography measuring the follicular diameters. Group N has significantly (p less than 0.025) higher E2 levels from day -10 up to d-6 as compared with the group P. The day of laparoscopy is designated day 0. In group N the length of E2 phase with E2 levels, exceeding 1.84 nmol/l (500 pg/ml) serum, is greater (p less than 0.001) than in group P 6.9 and 5.6 days, respectively. It is suggested that modifications occur in the endometrium caused by high E2 levels acting for a long time, which disturb the implantation of transferred embryos. No significant differences exist between group N and P, if the diameters of the largest follicle or the mean diameters of the secondary follicles or the number of follicles with a diameter greater than 14 mm are compared. No significant correlations were found between these variables and the E2 levels. A significant correlation (r = 0.85, 14 patients) exists between the E2 rise and the increase of follicular diameters.

Adult↗
PubMed1985

Nitrous oxide reductase from denitrifying Pseudomonas perfectomarina. Purification and properties of a novel multicopper enzyme.

Nitrous oxide reductase from the denitrifying bacterium Pseudomonas perfectomarina has been isolated and purified to homogeneity. The enzyme contained about eight copper atoms/120 kDa and was composed of two presumably identical subunits. The isoelectric point was 5.1. Several spectroscopically distinct forms of the enzyme were identified. A 'pink' form of the enzyme was obtained when the purification was done aerobically. The specific activity of this species was around 30 nkat/mg protein as measured by the nitrous-oxide-dependent oxidation of photochemically reduced benzyl viologen. A 'purple' form of the enzyme, whose catalytic activity was 2-5-fold higher, was obtained when the purification was done anaerobically. The activity of both forms of the enzyme was substantially increased by dialyzing the protein against 2-(N-cyclohexylamino)ethanesulfonate buffer at pH approximately equal to 10. A maximal activity of 1000 nkat/mg protein has been obtained for the purple form using this procedure. A 'blue', enzymatically inactive form of the enzyme resulted when either the pink or the purple species was exposed to excess dithionite or ascorbate. Anaerobic, potentiometric titrations of both the purple and the pink form of the enzyme gave a Nernst factor, n540, of 0.95 and a midpoint potential, E'0,540 of +260 mV (vs SHE, 25 degrees C, Tris/HCl buffer, pH 7.5). Electron paramagnetic resonance (EPR) and optical spectra of N2O reductase suggested the presence of an unusual type 1 copper center. Type 2 copper was absent. The hyperfine splitting in the g parallel region consisted of a seven-line pattern. In the presence of excess of reductant, a broad EPR signal with g values at 2.18 and 2.06 was observed. The EPR spectra of the pink and purple forms of the enzyme were similar; however, the spectrum of the purple form was better resolved with g parallel = 2.18 (A parallel = 3.83 mT) and g perpendicular = 2.03 (A perpendicular = 2.8 mT). Most of the copper in N2O reductase was removed by anaerobic dialysis against KCN. Reaction of the apoprotein with Cu(en)2SO4 partially regenerated the optical and EPR spectra of the holoprotein; the resulting protein was enzymatically inactive. Monospecific antibodies against the copper protein strongly inhibited the N2O reductase activity of purified samples and cell-free extracts.

Chromatography, Gel↗
PubMed1985

Isolation and characterization of transposon Tn5-induced mutants of Pseudomonas perfectomarina defective in nitrous oxide respiration.

Transposon (Tn5) mutagenesis of Pseudomonas perfectomarina with the plasmid pSUP2021 [(pBR325-Mob(RP4))::Tn5] and the chromosomally integrated RP4 plasmid in Escherichia coli as the donor, produced three distinct groups of mutants that were defective in nitrous oxide respiration. One group of mutants lacked the structural protein of N2O reductase, the second synthesized a copper-free apoprotein; and a third group expressed a low level of intact enzyme. The mutants provided evidence for N2O being the immediate precursor of dinitrogen in denitrification and documented the essentiality of the copper enzyme. Synthesis of N2O reductase depended strongly on the growth conditions, with N2O-grown cells expressing the lowest level of enzyme. Regulatory responses of mutants elicited by nitrate or oxygen were unaltered when compared with wild-type behavior.

DNA Transposable Elements↗
PubMed1984

[Pregnancies caused by in vitro fertilization in cycles, stimulated with human hypophyseal gonadotropin and chorionic gonadotropin].

In a program of in vitro fertilization, laparoscopies for oocyte aspiration were performed on 35 patients receiving human pituitary gonadotropin (hPG) and human chorionic gonadotropin (hCG). Of the 122 preovulatory oocytes which were recovered from these patients, 44 (36%) were fertilized and cleaved, and were transferred. 144 immature oocytes were collected, and attempts were made to mature these in vitro. 40 oocytes (28%) could be fertilized and cleaved, and were transferred. Eight pregnancies resulted from 32 embryo transfers (25%), and 22,9% from laparoscopies, respectively. Of the eight pregnancies, there were three preclinical abortions and two clinical abortions, and three patients are well along in the pregnancy. Among the three patients there is one twin pregnancy.

Adult↗
PubMed1983

[Prenatal diagnoses in a family with pericentric inversion of chromosome no. 5].

A hereditary pericentric inversion of chromosome 5(p13 leads to q35) was detected in a family after the birth of a child with Cri-du-Chat-syndrome [46,XY,del(5)(p13)]. Prenatal diagnoses were carried out in three pregnancies in this family. The following results were found in the amniotic fluid cells: first pregnancy 46,XX; second 46,XY, inv(5)(p13 leads to q35) and the third 46,XX,der (5)(pter leads to q35::p13 leads to pter). The first two pregnancies ended with the birth of phenotypically normal children; the third one however was interrupted. Fetal kidney tissue cultures confirmed the result of the amniotic fluid cell culture.

Adult↗
PubMed1982

[Familial balanced chromosome translocation t(12;13) in a family with several deformed stillbirths].

Reported in this paper is a family which was cytogenetically examined for several stillbirths with severe neural tube defects and other malformations. Balanced translocation between chromosomes 12 and 13 [t (12; 13) (q24; q22)] was recorded from five members of that family. Partial trisomy 13 or partial monosomy 13 is discussed as the cause of the malformations. Prenatal cytogenetic diagnosis had been undertaken in two cases.

Adult↗
PubMed1982

[Radio-immune assay for determination of testosterone and representation of Y-bodies - sufficiently dependable methods for prenatal diagnosis of sex (author's transl)].

Results obtained from prenatal diagnosis of sex by radio-immunological determination of testosterone in amniotic fluid are compared with findings recorded by representation of Y-bodies and with results of chromosomal analysis. In no single case was a false result obtained from the two former methods, when used together. Hence, chromosomal analysis proved to be necessary only in something between five and eight per cent of all examinations.

Amniotic Fluid↗
PubMed1982

[Current determination of ovulation time. 2. Optimization of timing for oocyte recovery].

Knowledge of probable ovulation date is essential to the recovery of pre-ovulatory oocytes for in vitro fertilisation. The authors used a commercially available LH-RIA kit for blood and urine samples together with the HI-Gonavis test for urine assay for high-accuracy determination of luteinising hormone (LH) in the peri-ovulatory cycle phase. Follicle status and oocyte quality were laparoscopically described of seven patients, between the eleventh and 16th days p.m. Optimum timing for oocyte recovery has not even become known by knowledge of LH rise. Different recommendations by other authors are discussed, and reference is made to unanswered problems.

Body Temperature↗
PubMed1981

[Methods for collection of human oocytes from ovary (author's transl)].

Collection and investigation of human oocytes are essential to the solution of certain medical problems. A total of 265 oocytes was obtained in the authors' own experiments from 34 surgical specimens, seven ovarian wedges, and 46 follicular punctates, all collected during operations. Oocytes may differ greatly in quantity and quality, depending on the original material or, more specifically, physiological condition of the ovaries, technique of collection, case history, and age of patient.

Adult↗
PubMed1979

Comparison of the immunologic reactions of arterial transplants in the arterial system and of venous transplants in the venous system using inbred strains of rats.

(1) Arterial transplants used as arterial replacements induce sensitization of the recipient in the weakly as well as in the strongly allogeneic systems (afferent limb). (2) Venous transplants used as venous replacements induce sensitization of the recipient (afferent limb). (3) Arterial transplants show increasingly severe rejection reactions paralleling the degree of immunogenetic difference (efferent limb). (4) Veins transplanted as venous replacements are tolerated even in the strongly allogeneic systems (efferent limb).

Animals↗