Biomedical subjects
Publications and source records attributed to A Möller.
The technique of percutaneous nephropyelostomy with specially prepared tubes is described. The advantages are secure positioning and good drainage. The splint allows diagnostic and therapeutic intervention. With certain indications the percutaneous renal fistula represents a great therapeutic advance.
The authors report on 34 successfully applied nephropyelostomies in 30 patients. The most frequent indication was obstruction of the uterus with retention of substances usually eliminated in the urine. The operation was carried out under local local anesthetic using a monitor. The rate of complication was very low. No deaths resulted. In the authors' opinion puncture nephrostomy is the best method of drainage in causes of obstruction with benign genesis. For carcinoma patients it must be individually decided whether this operation is indicated.
Antibodies which are specific to the Z-DNA conformation have been purified and characterized on the basis of their binding to three different DNA polymers which can form this left-handed helix. These antibodies bind specifically to polytene chromosomes of Drosophila melanogaster as visualized by fluorescent staining. The staining is found in the interband regions and its intensity varies among different interbands in a reproducible manner. This is the first identification of the Z-DNA conformation in material of biological origin.
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We prepared a brominated poly(dG-dC).poly(dG-dC) which forms a stable Z-DNA helix under physiological salt conditions. Rabbits and mice were immunized with brominated and unbrominated poly(dG-dC).poly(dG-dC) complexed with methylated bovine serum albumin. Antibodies specific for Z-DNA were produced. These antibodies were found not only in the sera of animals immunized with the low-salt stabilized Z-DNA [Br-poly(dG-dC).poly(dG-dC)] but also in sera from animals immunized with the unbrominated B-DNA form of the polymer. From this it is inferred that the unbrominated poly(dG-dC).poly(dG-dC) was partially converted to Z-DNA by its combination with the basic protein methylated bovine serum albumin. In addition to specific anti-Z-DNA antibody populations, two other interesting types of antibody populations were found. One of these reacted with both the Z and B forms of poly(dG-dC).poly(dG-dC). This antibody may be converting the polymer from the B-DNA to the Z-DNA form. The other type of antibody was specific for a B form of poly(dG-dC).poly(dG-dC) and did not react at all with the Z form. The antibodies raised to Z-DNA were shown to be highly specific for Z-DNA and did not react with B-DNA, RNA, DNA.RNA hybrids, or a number of other polynucleotides. This specificity for Z-DNA will make possible their use as reagents for determining the presence of Z-DNA in biological systems. Sera of autoimmune lupus mice were also shown to have a considerable amount of naturally occurring anti-Z-DNA antibody activity.
Poly(dG-dC).poly(dG-dC) was methylated at the N-7 position of guanine through the use of dimethyl sulfate. The conversion of poly(dG-dC).poly(dG-dC) from B-DNA to the Z-DNA form was followed by measuring both the circular dichroic spectra and changes in the absorbance ratio A295/A260. Increasing methylation steadily decreases the amount of NaCl or MgCl2 that is required to convert the polymer from B-DNA to Z-DNA. At 100% methylation of the guanine residues, the modified polymer is fully converted to Z-DNA in a physiological salt solution. Kinetic experiments show that methylation markedly accelerates the speed of the conversion from B-DNA to Z-DNA in the presence of added salt. These effects may be partly due to the positive charge on guanine that accompanies N-7 methylation.
We followed the binding of initiator and elongator tRNA to 70-S ribosomes and its subunits by velocity sedimentation in the analytical ultracentrifuge. This technique shows the advantage over the previously used methods (adsorption of the complexes to nitrocellulose filters or fluorescence titrations) in that no kinetic effects obscure the equilibrium data and that none of the components has to be chemically modified. The concentrations of the macromolecular compounds are kept constant and the binding equilibria are shifted by varying the Mg2+ concentration in a range which is accessible to experimental analysis. Free 30-S ribosomes bind no tRNA, whereas one tRNA molecule is bound to 50-S ribosomal subunits. In the presence of the cognate codon one tRNA can be associated with the small subunit. Free, programmed, or misprogrammed 70-S ribosomes bind exactly two elongator tRNAs. Only the initiator tRNA does discriminate significantly between the two ribosomal sites when bound to a ribosome . A-U-G complex.
A valve in distal direction was formed by means of invaginationion without opening the urinary tract in 15 undilated ureters in dog. After 3 months their function as an antireflux valve was checked. The result was good in 9 cases, a stenosis of the invaginat appeared in 4 cases and no antireflux effect was existing owing to the dislocation of the invagination in 2 cases. Details of the operative technique, causes of the failure, and the employment of the method in the human medicine were discussed.
Attenuation profiles across the petrous bone covering the whole internal auditory meatus (IAM) were constructed from the printouts obtained by computed tomography (CT) with narrow collimation performed on 12 patients with 13 acoustic neuromas. In healthy patients the attenuation profiles of right and left petrous bone were very similar in shape. The attenuation values of the individual pixels in the pixel columns of the printout located at the site of the porus and the IAM reflected the demineralization of the petrous bone and the widening of the porus and the IAM caused by the acoustic neuroma. A widening deep in the meatus was demonstrated in a patient with an intracanalicular tumor, and therefore it seems possible to make this diagnosis by CT scanning combined with the construction of attenuation profiles across the petrous bone. In the presence of unilateral acoustic neuroma there was a significant and characteristic difference in shape between the attenuation profiles of the two sides with generally lower attenuation values on the tumor side together with signs of widening of the porus and the IAM. In cases of bilateral acoustic neuroma comparison of the attenuation profiles can be made with mean attenuation curves obtained from scanning normal petrous bones. The prevailing physical limitations for demonstrating a narrow bony canal like the IAM with CT was experimentally analyzed using bone-simulating plastic material.
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Included in experiments with 185 sows with synchronised oestrus and ovulation were 52 untreated animals (K), while the others received intramuscular injections of daily doses of 75 mg of dexamethasone (DXMS), between the 109th and 111th days of pregnancy (V1) or 200 mg on the 110th day (V2) or on the 111th day (V3). While DXMS failed to have any substantive effect on mean pregnancy time or duration of labour, the variance of farrowing dates was reduced with significance. The average intervals which passed from the injections to delivery were 58.8 hours (V1), 82.2 hours (V2) or 54.8 hours (V3). No major difference was found to exist between K, V1, V2, and V3 regarding stillbirths or piglets with underweight, weights at birth and on the 21st day of age, loss in the course of raising, and percentual frequency of sows with normal or increased rectal temperature during the first three days after farrowing.
Forty-seven patients with 48 unoperated acoustic neuromas have been studied by computed tomography (CT) with respect to bone changes. CT and conventional X-ray examination of the skull were compared. The importance of using a small collimator, proper selection of the plane of the CT section and changing of the window level is stressed. CT detects porus changes as accurately as conventional X-ray methods.
From experiments with equilibrium dialysis it was concluded earlier that formation of the codon-anticodon complex triggers a conformational change in the tertiary structure of tRNAPhe from Escherichia coli. A similar conformational transition is demonstrated here in the poly(A)/tRNALys system. C-G-A or C-G-A-A was used as a probe for the conformational transition in tRNA. These probes bound to tRNAPhe and tRNALys more strongly in the presence of the corresponding codons than in the absence. In order to verify these data by an independent method, the decrease in absorbance at 300 nm that occurs on formation of the codon-anticodon complex in tRNALys (which contains 2-thio-5-methylaminomethyluridine, s2mam5U) was used. The binding constants for formation of A3 . tRNALys (Ka = 2.4 . 10(4) M-1) and A4 . tRNALys (Ka = 2.5 . 10(5) M-1) are very close to those obtained by equilibrium dialysis. In the presence of C-G-A the apparent binding constant of A3 to tRNA was raised 10-fold to 2.5 . 10(-5) M-1. It was calculated that the constant for the binding of C-G-A to the binary complex A3 . tRNALys is approximately 2 . 10(4) M-1, whereas binding to the free tRNA is lower than 10(3) M-1. Under appropriate conditions binding of A3 to tRNALys can be induced directly by the addition of C-G-A. These data demonstrate that codon-anticodon complex formation induces a conformational change in the tRNA that as a consequence allows the binding of a trinucleoside diphosphate, presumably to the T-psi-G region.
CT scans of 87 patients with subdural hematoma were compared to those of 393 patients with midline shift caused by other intracranial lesions with regard to attenuation changes in the lesion and the character of the ventricular deformity. Isoattenuating was exhibited by 25% of the subdural hematomas and 5% of the other lesions. In 70 to 80% of the isoattenuating hematomas, the diagnosis could be made on the basis of the characteristic ventricular deformity. Other diagnostic procedures are not necessary in these cases.
Forty patients with recurrent follicular pustules of the scalp but without obvious necrosis or residual scarring were re-examined (mean 8.3 years after onset of lesions). The most common age at onset was 20-40 years. The sex ratio (M/F) was 3 : 1. Only 7 of 40 patients had concomitant acne vulgaris on the face. All patients still had active, recurring scalp lesions, although 7 out of 40 had had temporary remissions. Post-lesional scarring was not observed. Oral low-dose tetracyclines had a symptomatic effect in 7 of 11 patients. Most of the patients treated topically with steroids and alcoholic lotions experienced little or no effect. Histopathology disclosed a neutrophilic folliculitis. Bacteriological examinations showed only the usual resident microflora of the scalp with P. acnes being the most frequent species. In 3 cases (5 examined pustules), P acnes was isolated from the content of the pustules without being found on the skin surface over the pustule. Chronic non-scarring folliculitis of the scalp probably constitutes a disease entity.
Seven pontine angle meningiomas were examined with computed tomography (CT). The result was compared with that of a study of 61 acoustic neuromas. These two tumor types differ in manner of growth, volume, shape, attenuation, attachment to bone, cisternal deformation, frequency of calcification, peripheral edema, and bone changes.
Sixty-one acoustic neuromas were examined with computed tomography (CT). For differential diagnosis the tumors were thoroughly analyzed for manner of growth, shape, volume, calcification, attenuation pattern, constrast enhancement, presence of peripheral edema, and cisternal deformation.