PubMed Health⌕ Search

Biomedical subjects

M Becker

Publications and source records attributed to M Becker.

At least 19 recordsLinked to original sources
PubMed1979

Spermine-DNA complexes build up metastable structures. Small-angle X-ray scattering and circular dichroism studies.

Spermine-DNA complexes have been examined by small-angle and wide-angle X-ray scattering as well as by circular dichroism studies. Condensed complexes are building up below a critical ionic strength. We have found that at one and the same ionic strength condensed complexes having two different supramolecular structures (Type I and Type II) can coexist. The structure of the condensates depends on the method of condensate formation. Phase transitions between these structures can be induced by thermal treatment. We conclude from these facts that with polyamine-DNA condensates metastable structures are of importance.

Animals↗
PubMed1979

Adenylate cyclase in human gastric mucosa: its activation by histamine in morphologically different biopsy specimens.

In morphologically different biopsy specimens from fundic, antral and duodenal mucosa of 134 persons, basal and histamine stimulated adenylate cyclase activity was studied: Basal and stimulated adenylate cyclase activities were log-normally distributed. Only in the fundic but not in the antral and duodenal mucosa adenylate cyclase was sensitive to histamine. The mean basal activity in the fundic gastric mucosa was 148, in response to 10(-5) mol/l histamine 292 pmol cAMP/mg protein/20 min. In human fundic biopsy specimens histologically identified as normal gastric mucosa, the stimulatory effect of histamine on adenylate cyclase decreased with the individual's age. In bioptic material from patients suffering from histologically proven chronic gastritis the histamine effect decreased with the degree of atrophy. A similar loss of histamine sensitivity was found in gastric mucosal biopsies of antrectomized individuals operated at least 5 years before by the Billroth I or II method, whereas in the mucosa of patients with gastric or duodenal ulcer no loss occurred. In contrast, the most pronounced stimulatory action of histamine was found in this latter group. Since a histamine sensitive adenylate cyclase is localized only in the glandular area of the fundic mucosa and the histamine sensitivity depends on a morphological intact structure of the mucosa, it can be concluded, that the effects of histamine on adenylate cyclase and on hydrochloric acid acid secretion have to be considered as a mechanism linked together.

Adenylyl Cyclases↗
PubMed1979

Pentagastrin activation of adenylate cyclase in human gastric biopsy specimens.

Adenylate cyclase activity of human fundic mucosa is log-normally distributed and equally stimulated by pentagastrin and histamine. Cimetidine inhibits the histamine, but not the pentagastrin effect, which is even intensified by H2-receptor blockade. The results indicate that pentagastrin and histamine activate adenylate cyclase via distinct receptors.

Adenylyl Cyclases↗
PubMed1979

[The Göttinger minipig as a laboratory animal. 5. Communication: cardiac output, its regional distribution and organ blood flow (author's transl)].

In 16 juvenile minipigs weighing 3.08 kg an average cardiac output of 23 ml/100 g body weight was measured with the dye-dilution method. The microsphere technique was used to assess distribution of cardiac output and organ blood flow. In 12 adult minipigs with a mean body weight of 21.5 kg the cardiac output of 14 ml/100 g body weight was measured with an electromagnetic flowmeter. The values of total systemic and organic blood flow correlated well with those of man and partly with those of other laboratory animals.

Animals↗
PubMed1979

[A contribution to the experimental procedure for testing anaesthetic drugs in the Göttinger minipig (author's transl)].

An experimental procedure is described for collecting base line data in awake, non-premedicated swine under standard conditions. We implanted catheters into the common carotid artery and in the external jugular vein, which were used either for taking blood samples or for access to the heart for a tip manometer and a flow-directed catheter. One week later we implanted an electromagnetic flow probe at the aortic root. With this preparation, the influence of one, two or several drugs on the heart, blood circulation and respiration can painlessly be demonstrated.

Anesthetics↗
PubMed1978

Transplantation of the small intestine. An experimental study in young minipigs.

An experimental study on small intestinal transplantation on 82 young minipigs is reported. The selected experimental model allows for early recognition of complications in the graft. A monitoring system, based on multiple sequential mucosal suction biopsies is presented, Transplanted segments up to 120 cm were rejected in similar way as are other organs. There was no evidence of a graft versus host reaction.

Animals↗
PubMed1978

Xenogenic response of human peripheral blood lymphocytes against murine cells in vitro.

Human peripheral blood lymphocytes (HPBL) were sensitized to mitomycin-treated murine spleen cells and mitomycin-treated mastocytoma P-815. A DNA proliferative response occurred to both cell types. The sensitized HPBL lysed chromium-51-labelled mastocytoma P-815 cells in a cell-mediated cytotoxicity assay (CMC). Evidence is presented that this human-murine xenogeneic system involves T cell response with specificity in CMC mainly toward H-2 antigens. DBA/2 splenocytes were superior to mastocytoma cells as sensitizers in the xenogeneic DNA proliferative assay.

Animals↗
PubMed1978

The risks of small intestinal transplantation for the recipient: experimental results in young minipigs.

In a previous series of 36 small intestinal transplants in young minipigs, a monitoring system, based on a special transplantation model, clinical and histologic criteria has been worked out. The spontaneous evolution was observed and no attempt was made to save the animal when complications on the graft occurred. Most of the animals died. In the present series of 32 small intestinal transplants the monitoring system and explanation criteria are now tested. Twenty-three primarily successfully transplanted animals had complications of the graft, i.e., hemorrhagic infarction, deficient arterial circulation, or rejection. Only 1 of the 23 died before explanation could be done. Twenty-two were explanted according to the previously established criteria. Two died of complications not directly related to the graft, the other 20 animals survived for 1-5 mo. All 22 explanted grafts showed irreversible damages both macroscopically and on histologic examination. The present series confirms that early recognition of complications of the graft and timely removal with survival of the recipient animal is possible. This could be an important step forward to the clinical application of small intestinal transplantation in man.

Animals↗
PubMed1978

Study of DNA-spermine interactions by use of small-angle and wide-angle X-ray scattering and circular dichroism.

Circular dichroism measurements with DNA-spermine complexes at 0.075 M NaCl and at 0.15 M NaCl reveal +psi (type I) and -psi (type II) CD spectra respectively. From small-angle X-ray scattering studies it could be shown that type I has a long-range order, short-range order supramolecular structure, while type II is of long-range disorder, short-range disorder structure. The secondary structure of the DNA in both types of condensates is B-like as concluded from wide-angle X-ray scattering diagrams of the condensates and from a comparison with the wide-angle X-ray curves of DNA and RNA in solution.

Animals↗
PubMed1978

Brain-typical creatinekinase in the serum of newborn infants with perinatal brain damage.

The normal values of serum-CK-activity in healthy newborns varied greatly (95% range: 4--165 U/l; 257 probands) and the borderline to pathological values was not sharp. Brain-typical CK-isoenzyme (CK-BB) could be detected in serum of 6 of 8 infants with perinatal brain damage by means of agar gel electrophoresis. The combination of neuropathological symptoms, increased total-serum-CK-activity, and significant amount of CK-BB in serum seemed to be a sure sign of severe CNS-damage in newborns.

Brain Diseases↗
PubMed1978

Rheumatoid arthritis and its variants: analysis of scintiphotographic, radiographic, and clinical examinations.

99mTc pyrophosphate radionuclide scans of the axial and appendicular skeletons in 23 patients with rheumatoid arthritis and 15 patients with systemic arthritic conditions were compared to clinical and radiographic examinations. The nuclear scan was the most sensitive indicator of active disease and correlated extremely well with the other methods. A pattern of abnormal radionuclide activity in rheumatoid arthritis consisting of a symmetric peripheral joint process can be distinguished from that of the rheumatoid variants which tend to have more central skeletal involvement and asymmetric peripheral articular involvement. The nuclear scan is less specific than the radiograph in its ability to distinguish among the clinical entities. However, documentation of scintigraphic activity often antedated radiographic or clinical abnormalities.

Adult↗
PubMed1978

[Technique of the introduction of duodenal sounds in children (author's transl)].

Duodenal Sounds, provided they are sufficiently rigid, can be introduced actively with simultaneous x-ray control. Good sedation promotes rapid passage; further important aids are: appropriate positioning of the patient, instillation of air, and palpation. In recent years, intravenous administration of diazepam and metoclopramid has proved successful as premedication. The described procedure reduces the strain on the children and the amount of time required by the medical staff.

Child↗