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G Petersen

Publications and source records attributed to G Petersen.

90 records · Page 5Linked to original sources
PubMed1981

Distribution of spacer length classes and the intervening sequence among different nucleolus organizers in Drosophila hydei.

Drosophila hydei rRNA genes from different chromosomes and from different stocks have been studied by restriction enzyme analysis. In DNA from wild-type females, about half of the X chromosomal rRNA genes are interrupted by an intervening sequence within the 28S coding region. In contrast to D. melanogaster, the intervening sequences belong to a single size class of 6.0 kb. Although there are two nucleolus organizers on the Y chromosome, genes containing the intervening sequence seem to be restricted to the X chromosome. -- As shown in four cloned rDNA fragments, the nontranscribed spacers differ in length by having varying numbers of a 242 base pair sequence located in tandem in the right section of the spacer. In genomic rDNA, the spacers also differ in length by a regular 0.25 kb interval. Spacers with between 5 and 15 subrepeats occur frequently within the X and Y chromosomal nucleolus organizers in different D. hydei stocks; shorter and longer spacers are also present but are relatively rare. -- Although each genotype is characterized by different frequencies of some spacer classes, the prominent spacer length heterogeneity pattern is similar among the different nucleolus organizers and, therefore, seems to be conserved during evolution.

Animals↗
PubMed1979

Genetic heterogeneity of hyperpepsinogenemic I and normopepsinogenemic I duodenal ulcer disease.

In a search for a genetic marker of duodenal ulcer, we measured serum pepsinogen I levels in 168 ulcer patients and 151 of their clinically normal siblings. The ulcer patients tended to have either hyperpepsinogenemia I (pepsinogen I, greater than or equal to 100 ng/mL) or a normal level on a familial basis. Further evidence supporting this separation was the finding that the mean serum pepsinogen I level in the clinically normal siblings of the hyperpepsinogenemic patients was 91.2 ng/mL, significantly higher than the mean level (63.1 ng/mL) in the normal siblings of the normopepsinogenemic I patients. In the hyperpepsinogenemic I families the results of segregation analysis of an elevated pepsinogen I were consistent with autosomal-dominant inheritance of this trait. The genetic basis of normopepsinogenemic I duodenal ulcer was also shown by the familial aggregation of this disorder. These data provide direct evidence for genetic heterogeneity of duodenal ulcer disease.

ABO Blood-Group System↗
PubMed1977

Field estimation of VO2 max in children eight years of age.

The purpose of the investigation was to explore the validity of using timed distance runs as predictorr of cardiorespiratory fitness in young untrained children. Maximal oxygen consumption and performance in runs of 549, 1207, and 1609 meters (600 yards, 3/4 mile, and 1 mile) were compared in 38 children eight years of age. Males were found to exceed females on Vo2max and possessed significantly faster times in the 1207 and 1609 meter runs. The females exhibited greater six-site skinfold totals. The 1609 meter run proved to be the best predictor of Vo2max (ml/kg) in males. However, none of the three distances was acceptable for females.

Adolescent↗
PubMed1977

Complement as an essential factor for indirect immunofluorescence in cases of pemphigoid.

Hitherto in the literature no proof has been published of a complement activation on the basement membrane in cases of pemphigoid. In this paper, for the first time, it is demonstrated, even if only in vitro, that complement, whose presence in the region of the basement membrane has long been known, plays an active role in a reaction. Through the action of the haemolytic system (amboceptor and sheep erythrocytes) and of anti C3 on reaction specimens for indirect immunofluorescence in pemphigoid, it is shown that the indicator reaction of the fluorescein-labelled anti-IgG with the immune complex attached to the basement membrane is markedly dependent on complement. Free, dissolved IgG is precipitated by appropriate anti-serum, even without complement.

Antigen-Antibody Complex↗
PubMed1977

Investigations on the binding sites of the basement membrane zone for pemphigoid antibodies in vitro. II. Immunohistochemical reactions of the reactive groups.

In continuing our studies on the characteristics of the antigenic structures of the basement membrane, procedures used in histochemistry for the identification and blocking of reactive groups have been adapted in this present work to the pretreatment of cryostat sections of guinea-pig tongue. These sections have then been studied by the indirect immunofluorescence method. By means or reagents, which produce a reversible extinction of the basement membrane fluorescence produced with pemphigoid sera, it proved possible to determine the existence of certain chemical groupings which bind the anti-basement membrane antibodies, namely: free carboxyl groups deriving from amino acids, hydrogen bridges in which the hydroxyl groups from the carbohydrates in the antigen are probably involved, bonds involving the free aldehydes of the antigen (either cross-links from aldehydes, or formation of Schiff's bases with amino groups of the antibodies), and lastly, to a lesser extent, disulphide bonds. The antigen/antibody reaction probably occurs in the neighbourhood of the alpha-glucosido-beta-galactosido-hydroxylysine. A reaction model has been developed from these findings. There were also some indications that the antigenic structures of the intercellular substance are chemically related to those of the basement membrane. The cell nucleus antigens, on the other hand, appear to possess different chemical properties.

Animals↗
PubMed1976

The activation of antigens of the basement membrane zone by proteolytic enzymes in vitro.

Following brief exposure of cryostat sections of human skin to the action of proteolytic enzymes (papain or trypsin), there was a pronounced increase in the antibody binding sites of the basement membrane zone, shown in indirect immunofluorescence by an increased intensity in fluorescence of the basement membrane zone as compared with preparations which had not previously undergone incubation, and by an increase of 5-6 (papain) or 4-5 (trypsin) titre dilution steps. This effect was practically absent when guinea-pig tongue was used as the antigenic substrate. In conjunction with findings published in the literature, our results can be interpreted as indicating that the activation of the basement membrane zone antigens by proteolytic enzymes is associated with an increase in antigenicity which results in the formation of "auto-antibodies" of the basement membrane zone antibody type.

Antibody-Producing Cells↗
PubMed1975

[The mechanism of antigen-antibody reaction at the basement membrane zone in bullous pemphigoid. The question of interaction of complement factors and bivalent cations (author's transl)].

1. In a medium poorly cationic indirect immunfluorescence of the basement membrane zone normally observed with preparations of sera from patients with pemphigoid has not be seen. 2. The fluorescence of basement membrane zone takes place if Fe2+ ions are added together with the antibasement zone antibodies. Evidently Fe2+ ions are essential for fixing antibodies. 3. With the method of indirect fluorescence the C3 component of complement could be observed after fixation of pemphigoid antibodies to the basement membrane zone. 4. EDTA prevents binding C3 too. Only after adding Fe2+ (not with Ca2+ or Mg2+) complement IF staining is demonstrable. Apparently EDTA causes the loss of fixing antibasement zone antibodies at first. Thereafter complement staining reaction is negative. 5. Participation of C1 could not be demonstrated using indirect IF staining. The alternate pathway to activation of C3 is discussed.

Antigen-Antibody Reactions↗
PubMedDate not supplied

Bioequivalence of two commercially available tamoxifen tablet formulations in healthy male volunteers.

Tamoxifen, a non-steroidal antiestrogen, is used in the palliative treatment of advanced breast cancer and as an adjuvant therapy after mastectomy. The bioequivalence of tamoxifen following single oral doses of Zemide 20 and a commercially available tablet formulation (reference formulation), each containing 30.4 mg tamoxifen dihydrogencitrate corresponding to 20 mg tamoxifen was investigated in 12 healthy male subjects. In a randomized, crossover study with a washout period of 13 weeks the volunteers received one pharmaceutical unit of both formulations after an overnight fast on an empty stomach. Plasma concentrations of tamoxifen were determined at predose and predetermined time points up to 20 days after administration using a validated HPLC method. The two tamoxifen formulations were proven to be bioequivalent for tamoxifen regarding rate and extent of absorption. The bioequivalence decision was based on Cmax, tmax and AUC0-t.

Administration, Oral↗