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Biomedical subjects

F Schmidt

Publications and source records attributed to F Schmidt.

At least 163 records · Page 9Linked to original sources
PubMed1985

[Compression/flexion fractures of the radius base (Smith fractures)].

Out of 416 Colles-fractures we observed 18 of the Smith-type. The Smith fracture is a rare injury, it will generally occur in consequence of a fall on the supinated hand which is forced in pronation. The dislocation of the carpus and peripheral fragment is in the volar and proximal direction. It should be treated operatively, especially in intraarticular fractures. Surgical treatment of patients will result in better movability of he wrist and intact distal joint surfaces.

Adult↗
PubMed1984

Evolutionary relationship between Tn21-like elements and pBP201, a plasmid from Klebsiella pneumoniae mediating resistance to gentamicin and eight other drugs.

We have characterized pBP201 one of the plasmids from a collection of 46 strains producing adenylyltransferase ANT(2") (Schmidt 1984). It confers resistance to sulphonamides and produces aminoglycoside adenylyltransferases AAD(3") and ANT(2") and beta-lactamase TEM-1. Plasmid pBP201 has a size of 24.8 kilobases (kb) and contains TnA and a Tn21-related element, Tn4000 delta, with deletions in mer and the termini and a substitution at tnpR. In complementation assays with transposition-deficient mutants of Tn21 the element in pBP201 appears to be TnpA+ but TnpR-. It represents a naturally occurring defective transposon. The sequence organization of pBP201 has been compared with that of Tn21-related elements such as Tn2410, Tn2603, Tn2424, Tn1696, and Tn4000. In these transposons the integration sites of resistance genes cat, bla, aacA, aacC or aadB have been identified at two preferential locations; these are at the termini of the streptomycin resistance gene aadA. Two additional sites have been localized in the Tn21 backbone to the right of the mer operon and at res (internal resolution site) and are probably involved in the evolution of these elements. Based on these results a model for the possible genealogy of class II transposons is presented.

Aminoglycosides↗
PubMed1984

The role of insertions, deletions, and substitutions in the evolution of R6 related plasmids encoding aminoglycoside transferase ANT-(2").

In 7% of gram-negative bacteria resistance to gentamicin is mainly mediated by plasmid-encoded aminoglycoside transferase ANT-(2"). The genome organization of 15 aadB plasmids (42-110 kb) was analyzed by restriction and hybridization techniques. They appeared to be IncFII-like replicons but were distinct from R6 by virtue of small substitutions in the transfer region. Aminoglycoside resistance genes aadB and aadA were located on Tn21 related elements. Only one of them was able to transpose its resistance genes mer sul aadA and aadB ( Tn4000 ), the other elements were naturally occurring defective transposons. In some of these structures deletions were identified at the termini, at sul, aadA , mer or transposition function--insertions adjacent to aadA or mer. The mode of these rearrangements and their site-specificity were considered with respect to the evolution of the Tn21 transposon family.

Aminoglycosides↗
PubMed1984

Species differences in the sensitivity to the antitesticular effects of [Ac-D-NAL(2)1, 4FD-Phe2, D-Trp3,D-Arg6]-LHRH, a potent LHRH antagonist.

The antigonadal effects of [Ac-D-NAL(2)1, 4FD-Phe2, D-TRP3, D-Arg6]-LHRH (LHRH-A), a potent antagonist of LHRH, were investigated in rats and rabbits. Rats and rabbits were given LHRH-A (1250 micrograms/kg) daily for 15 days. Some animals were killed on day 16 (24 h after the last treatment) while others were mated. In the male rats serum LH and testosterone levels as well as the weights of sexual organs were significantly reduced. Mating behavior and fertility that were suppressed by the end of treatment returned to normal by 7 weeks after last treatment. In contrast to rats, the testicular function and fertility of rabbits appeared unaffected by LHRH-A treatment. The difference in the response between rats and rabbits led us to compare the response of rats and mice. Male rats and mice were given LHRH-A (1450 micrograms/kg) daily for 5 days and killed on day 6. In rats LHRH-A caused a 93% decrease in serum T and 88% decrease in in vitro testicular T production. In mice, however, the Leydig cell function remained unaffected when examined 24 h after the last dose of LHRH-A. To explain the differences between the effects of LHRH-A on rats, rabbits and mice, the acute effect of this peptide on serum T levels was investigated in these species. Administration of a single dose of LHRH-A (1250 micrograms/kg) led to a rapid decrease in serum T that was sustained for 24 h in rats. In rabbits and mice, however, the same dose of LHRH-A caused only a transient decrease in serum T. Male rhesus monkeys treated with LHRH-A (1000 micrograms/kg) also showed a transient decrease in serum T concentrations. It is concluded that there are considerable species differences in the sensitivity to the antigonadal effects of LHRH-A.

Animals↗
PubMed1984

[Ac-D-NAL(2)1,4FD-Phe2,D-Trp3,D-Arg6]-LHRH, a potent antagonist of LHRH, produces transient edema and behavioral changes in rats.

Acute toxicity studies of [Ac-D-NAL(2)1,4FD-Phe2,D-Trp3,D-Arg6]-LHRH (LHRH-A), a potent antagonist of LHRH were performed. Subcutaneous administration of this peptide to rats induced transient edema of the face and extremities. This effect was maximal 3-5 h after peptide administration and subsided by 24 h. These effects were not seen with an LHRH agonist or two other antagonists. This side effects of LHRH-A was peculiar to rats and not observed in mice, rabbits and rhesus monkeys. Intravenous administration led within minutes to depression of spontaneous activity in rats and monkeys. We conclude that some LHRH antagonists produce species specific effects on vascular permeability and spontaneous activity.

Animals↗
PubMed1984

Ovulation inhibition in the pregnant mare's serum gonadotropin-treated immature rat: a bioassay for luteinizing hormone-releasing hormone antagonists.

A convenient method for evaluating the biological activity of luteinizing hormone-releasing hormone (LHRH) antagonists was devised. Pregnant mare's serum gonadotropin (PMSG) treatment of immature rats is known to stimulate follicular growth and estrogen production, that in turn stimulates the release of LHRH which triggers an ovulatory discharge of luteinizing hormone (LH) from the pituitary. The present bioassay of the antagonists is based on the inhibition of ovulation in the PMSG-treated rats. Twenty-eight-day-old Sprague Dawley rats maintained under a light period of 12 h/day (lights on at 0630 h) were given 10 IU of PMSG s.c. at 0930 h. On Day 30 of age the antagonist was given s.c. at 1430 h. The rats were killed on the following morning and the oviducts examined for the presence of ova. In addition, the antagonists were compared in their ability to inhibit serum testosterone levels in adult male rats. In the PMSG-treated rats the order of ovulation-inhibiting potency of the following antagonists was: [Ac-D-NAL(2)1,4FD-Phe2,D-Trp3,D-Arg6]-LHRH (LHRH-1) greater than [Ac-delta 3 Pro1,4FD-Phe2,D-NAL(2)3.6]-LHRH (LHRH-2) greater than [Ac-delta 3 Pro1,4FD-Phe2,D-Trp3,6]-LHRH (LHRH-3). The order of potency was confirmed by their antitesticular effects in adult male rats.

Animals↗
PubMed1983

Identification of Tn2401, a transposon encoding multiresistance to aminoglycosides.

A transposable element, Tn2401, was found in a clinical isolate of Pseudomonas aeruginosa. Tn2401 had a size of 7190 nucleotides and encoded aminoglycoside 3'-phosphotransferase and aminoglycoside 6'-N-acetyltransferase. The sequence encoding the former enzyme was homologous with that of Tn903. Pseudomonas aeruginosa strains harbouring this transposon were resistant to kanamycin, neomycin, lividomycin, ribostamycin, paromomycin, netilmycin, tobramycin, dibekacin, gentamicin, sisomicin, and butirosin.

Acetyltransferases↗
PubMed1983

Transposition of a gene encoding OXA-2 beta-lactamase.

A bla gene encoding OXA-2 beta-lactamase has been transposed from the Salmonella typhimurium R plasmid R1767. This transposable element which was designated Tn2410 encoded sulphonamide and mercury resistance in addition to the bla gene. It had a size of 18.5 kb and appeared to be flanked by small inverted repeats. Restriction enzyme analysis resulted in a detailed map of Tn2410, which showed a high degree of similarity with the published map of Tn2603, a transposon encoding OXA-1 beta-lactamase. The ampicillin and sulphonamide resistance genes on Tn2410 were mapped in a cluster on the region between the centre and the righ end of the map.

Ampicillin↗
PubMed1983

Characterization of Tn2411 and Tn2410, two transposons derived from R-plasmid R1767 and related to Tn2603 and Tn21.

Two transposable elements, Tn2410 and Tn2411, were isolated from Salmonella typhimurium R-factor R1767. They have sizes of 18.5 and 18.0 kilobases, respectively. Tn2411 mediates resistance to streptomycin, sulfonamides, and mercury. In Tn2410, the streptomycin resistance gene was replaced by a gene coding for the production of the beta-lactamase OXA-2, which is responsible for ampicillin resistance. Physical and functional maps of both transposons were compared with those of Tn21, Tn4, and Tn2603. From these data it appeared that Tn21 could be an ancestral transposon from which Tn2411, Tn2410, Tn2603, and Tn4 were evolved by the addition or deletion of small DNA segments.

Ampicillin↗
PubMed1983

[Value of computer tomography in the diagnosis of the extent of tumors of the female genitals and the bladder].

The particular benefit of computed tomography (CT) is diagnosis of tumours exceeding organ boundaries and producing regional metastases. CT contributes to precise pretherapeutic staging, however, its value depends on tumour type, localization and stage. The main application of CT is the diagnosis of recurrencies of malignant tumours of rectum, uterus and ovary. The wide range of diagnostic application also in diagnosis of distant metastases makes CT superior to all other radiological methods.--In primary diagnosis of tumours of the female genital organs and urinary bladder CT is of minor importance. It has a limited value in ovarian tumours.

Female↗