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Biomedical subjects

F Peters

Publications and source records attributed to F Peters.

At least 55 records · Page 3Linked to original sources
PubMed1988

[Self-inflicted necroses (mastitis factitia) as an unusual course of non-puerperal mastitis].

The present paper reports of a long lasting necrotising mastitis which, regarding the psychiatric aspect of the patient as well, has to be interpreted as artefactual mastitis. The uncommon localisation, the unusual history and histology as well as the hardly accessible personality may be indicative of a self inflicted injury with subsequent inflammation. Additional to the local therapy, these patients need a psychological guidance, avoiding direct confrontation with the suspected pathogenesis.

Abscess↗
PubMed1988

[Gonadotropin resistance in Rothmund-Thomson syndrome].

A case of Rothmund-Thomson syndrome of a 24-year old woman with primary amenorrhoea is presented. This autosomal recessive disorder is characterised by atrophy, hyperpigmentation and teleangiectasiae of the skin, furthermore by juvenile cataracts and congenital bone defects as saddle nose. Endocrinologic and morphologic parameters suggest a resistant ovary syndrome as cause of this hypergonadotropic hypogonadism.

Adult↗
PubMed1987

The role of translocation in ribosomal accuracy. Translocation rates for cognate and noncognate aminoacyl- and peptidyl-tRNAs on Escherichia coli ribosomes.

The ribosomal translocation, as measured in vitro by peptide formation on poly(U)-programmed Escherichia coli ribosomes in the presence of ternary complex, deacylated tRNA or N-acetyl-Phe-tRNA, and elongation factor G, is the rate-limiting step of protein synthesis. Elongation factor G stimulates the spontaneous translocation by a factor of about 500. N-Acetyl-Phe-Phe-tRNA(Phe E. coli) is translocated with a rate constant of 1-2 s-1 at 25 degrees C. Translocation of N-acetyl-Phe-Phe-tRNA(Phe yeast) and N-acetyl-Phe-Leu-tRNA(Leu E. coli) under identical conditions proceeds with a rate by about a factor of 2 and 10, respectively, more slowly. The translocation rate, therefore, is influenced by the nature of the tRNAs in the A-site. We can show, furthermore, that also the tRNA in the P-site, and presumably in the E-site as well, influences the rate of translocation. Reduced rates of translocation of noncognate peptidyl-tRNAs are accompanied by preferential dissociation of these tRNAs at the beginning of the translation of a mRNA.

Escherichia coli↗
PubMed1986

Inhibition of lactation by a long-acting bromocriptine.

A long-acting form of bromocriptine, a prolactin (PRL) secretion inhibitor, was administered to 122 postpartum women in single intramuscular injections of 20 (N = 24), 30 (N = 22), 40 (N = 46), and 50 mg (N = 30). In 91 women the substance was administered immediately after delivery to prevent galactopoiesis and in the remaining 31 women to inhibit established lactation. Effectiveness was estimated by the absence of breast engorgement and of milk secretion. Successful prevention or inhibition of lactation was highest among women receiving 50 mg bromocriptine (97%), and comparison between dosages revealed a close linear dose-response relationship (r = 0.98). Persistent and significant (P less than .001) PRL inhibition could be recorded for up to 22 days in successfully treated puerperas in comparison with 12 normally breast-feeding women who served as control subjects. No significant side effects or local reactions were recorded. Eleven of 46 postpartum women receiving 20 or 30 mg bromocriptine experienced onset of milk secretion or lactation rebound, and responded to oral administration of the drug. The presence of milk was associated with plasma PRL concentrations persistently above 25 ng/mL in all of them, whereas nine women in the same dosage range in whom lactation suppression was effective exhibited values below this limit. Dose-response data allow the establishment of a putative PRL threshold for induction of milk secretion of about 25 ng/mL. Maintenance of plasma PRL values below this limit prevents lactogenesis and inhibits lactopoiesis.

Bromocriptine↗
PubMed1985

Thyroid hormones in benign breast disease. Normalization of exaggerated prolactin responsiveness to thyrotropin-releasing hormone.

To investigate the exaggerated prolactin (PRL) responsiveness to thyrotropin-releasing hormone (TRH) in patients with benign breast disease (BBD), 18 patients and 13 healthy controls underwent an 8-week-long thyroid hormone treatment. The clinical effect of thyroid hormones on cyclical mastodynia and concomitant galactorrhea was evaluated. TRH-stimulated PRL and thyroid-stimulating hormone (TSH) responses and thyroxine, triiodothyronine, thyroxine-binding globulin, as well as serum estradiol and progesterone levels, were measured before and during hormone treatment. Thirteen of the patients and one of the controls had euthyroid diffuse goiter. Patients and controls had normal thyroid function parameters. During thyroid hormone treatment, significantly elevated TRH-induced PRL responses of the patients decreased by 50% and reached levels of the controls, whereas responses of the controls decreased insignificantly. Patients exhibited significantly lower serum progesterone levels than the controls; the estradiol levels were not different. Thyroid hormone treatment had no significant influence on luteal function of patients or controls. In 16 of 18 patients thyroid hormones were of benefit to mastodynia, whereas galactorrhea remained unaffected.

Adolescent↗
PubMed1985

[Non-puerperal mastitis. Etiology, clinical aspects and therapy].

Non-puerperal mastitis was diagnosed in 79 patients (aged 12-77 years) over the years 1974-1984. Malignant neoplasm was not present. Bacterial infection in the region of the areola was the most frequent finding (40%), followed by abacterial inflammation without involvement of the nipples (29%). The other cases, bacterial or nonbacterial, occurred at different sites. The histological picture or clinical features of an increased secretory activity of the mammary gland (galactorrhoea, mastodynia) in addition to the mastitis was noted in 54 women. Causative organisms were proven in 53% of cases: Staph. aureus (41%) and coagulase-negative staphylococcus (41%), or anaerobic organisms (11%). Physical measures, antibiotics and bromocriptine were used as treatment. At the onset of treatment abscesses were already present or developed in 34 instances. In 28 cases one to six recurrences set in after the end of the treatment period. In 22 patients treated with bromocriptine prophylactically there were only two recurrences. In the majority of patients an increased alveolar secretion was important in the pathogenesis of the bacterial or abacterial inflammation. Prolactin-lowering treatment seems reasonable by itself in cases of abacterial mastitis, or in combination with antibiotics in bacterial mastitis. Recurrences can be prevented by long-term lowering of the peripheral prolactin level.

Adolescent↗
PubMed1985

Ovarian hyperstimulation due to long-term pulsatile intravenous GnRH treatment.

Pulsatile long-term gonadotropin releasing hormone (GnRH) therapy with an average dosage of 8 micrograms/pulse i.v. in intervals of 90 min induced in a patient with hypothalamic amenorrhea the development of multiple ovarian cysts as visualized by ultrasonography. Estradiol (E2) plasma concentration reached values of 5000 pg/ml. These findings indicate that pulsatile GnRH application can induce ovarian hyperstimulation.

Adult↗
PubMed1985

Serum prolactin levels in women with excessive milk production. Normalization by transitory prolactin inhibition.

Serum prolactin levels and milk yield were studied in 27 puerperae with excessive milk production (polygalactia) and compared with 30 normally lactating puerperae. In order to normalize polygalactia, 14 of these women were treated with 2.5 mg bromocriptine per day for 3 days starting on post-partum day 5, 13 women received placebo. Milk flow in polygalactic women started significantly earlier than in puerperae with normal milk yield and developed mean milk volumes of 816 g per day on post-partum day 4. Serum prolactin levels did not differ from levels of puerperae with normal milk yield. There was no correlation between serum prolactin and milk yield. Bromocriptine treatment resulted in a sharp but reversible decline of serum prolactin levels followed by a significant reduction of milk production. Bromocriptine could not be detected in milk specimens, while serum levels showed significant amounts. In placebo treated women prolactin levels and milk yield remained unaffected. These data indicate that serum prolactin concentrations of puerperae with polygalactia are within the normal post-partum range. Short term prolactin suppression by bromocriptine can reduce milk yield, without complete ablactation.

Bromocriptine↗
PubMed1984

The influence of sequences adjacent to the recognition site on the cleavage of oligodeoxynucleotides by the EcoRI endonuclease.

We have investigated the influence of the nucleotide sequence adjacent to the recognition site on the rate of cleavage of DNA by the restriction endonuclease EcoRI. For this purpose two decadeoxynucleotides, d(G-G-G-A-A-T-T-C-T-T) (Ia) and d(A-A-G-A-A-T-T-C-C-C) (Ib) were synthesized. The duplex Ia X Ib is cleaved by EcoRI preferentially in the dA-rich strand (approximately 10 times over the dG-rich strand). The individual nucleotides Ia and Ib are also cleaved by EcoRI, Ib at a higher rate than Ia and both at a lower rate than Ia X Ib. The temperature dependence of the reaction rate shows that only double-stranded oligodeoxynucleotides are substrates for the EcoRI endonuclease. We have, furthermore, synthesized oligomers of d(G-G-A-A-T-T-C-C), which contain two, three and four EcoRI sites, respectively. These oligodeoxynucleotides are preferentially cleaved at the sites next to the 5' end, where the recognition site is only flanked by one dG X dC base pair, in contrast to the other sites which are flanked by three such pairs. These data indicate that sequences adjacent to the recognition site influence the rate of cleavage: dA X dT base pairs enhance and dG X dC base pairs slow down the hydrolytic activity of the EcoRI endonuclease.

Base Composition↗
PubMed1984

Serum prolactin levels in patients with fibrocystic breast disease.

In 193 patients suffering from fibrocystic breast disease, basal serum prolactin concentrations were determined and compared to serum prolactin levels in 193 healthy women. In 45 additional patients and 23 healthy control subjects, a thyrotropin-releasing hormone (TRH) stimulation test was performed. The response to TRH in seven healthy female volunteers and in one patient with fibrocystic breast disease, was correlated with the mean serum prolactin levels over 24 hours. Serum prolactin levels were above normal in 45.6% of the patients and in 21.2% of the control subjects. Mean values of the two groups were significantly different (P less than .001). The maximum prolactin response to TRH stimulation was significantly higher in the study patients than in the control subjects (P less than .001). The TRH-stimulated prolactin response correlated positively with the mean 24-hour level (P less than .01, r = 0.8705). These results indicate that a high proportion of patients with fibrocystic breast disease exhibit increased daily prolactin secretion.

Adolescent↗
PubMed1983

The elongation factor Tu from Escherichia coli, aminoacyl-tRNA, and guanosine tetraphosphate form a ternary complex which is bound by programmed ribosomes.

The interaction of the Escherichia coli elongation factor Tu guanosine tetraphosphate complex (EF-Tu ppGpp) with aminoacyl-tRNAs(aa-tRNA) was reinvestigated by gel filtration and hydrolysis protection experiments. These experiments show that EF-Tu X ppGpp like EF-Tu X GDP (Pingoud, A., Block, W., Wittinghofer, A., Wolf, H. & Fischer, E. (1982) J. Biol. Chem. 257, 11261-11267) forms a fairly stable complex with Phe-tRNAPhe, KAss being 0.6 X 10(5) M-1 at 25 degrees C. The binding of the EF-Tu X ppGpp X aa-tRNA complex to programmed ribosomes was investigated by a centrifugation technique. It is shown that this complex is bound codon-specific with KAss = 3 X 10(7) M-1 at 0 degrees C and that it stimulates peptidyl transfer. A numerical estimation of the intracellular concentration of EF-Tu X GTP X aa-tRNA and EF-Tu X ppGpp X aa-tRNA during normal growth and under the stringent response indicates that ppGpp accumulation does affect the EF-Tu X GTP X aa-tRNA concentration but does not lead to major depletion of this pool. Furthermore, due to the higher affinity of EF-Tu X GTP to aa-tRNA and of the ternary complex EF-Tu X GTP X aa-tRNA to the ribosome, EF-Tu X ppGpp X aa-tRNA binding to the ribosome is not significant. According to our measurements and calculations, therefore, a direct participation of EF-Tu in slowing down the rate of protein biosynthesis and improving its accuracy during amino acid starvation is not obvious.

Escherichia coli↗